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We do not, of course, generally neglect the question if and how the choice of an adequate frequency model is modified depending on these pre-conditions — it is simply not pursued in this paper which has a different accent. At Travelers, we stay ahead of the curve on emerging risks and evolving threats by tracking developments in the field and monitoring expert opinions on the consequences to our customers. Examples include hypodermic needles, syringes, applicators, bandages and wraps, drug tests, exam gowns, face masks, gloves, suction catheters, and surgical sponges. What are tubing connectors? This contrasts to subtractive processes, such as the NC machining of traditional manufacturing, in which material is removed rather than being added. Seiten 2 – 1 2. What is prototyping? Japanese Reinforced tubing is typically used to support access devices or as a delivery method for another device.❿
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Windows 10 1703 download iso itar regulations governing – windows 10 1703 download iso itar regulati.Medical Design & Outsourcing – MEDICAL DEVICE HANDBOOK – Dec. 2015
This program is ideal for smaller volume purchases with quick turnaround needs, in addition to standard accessories including covers, sensors, sensor rails and brackets. To download your free reference guide and linear actuator catalog, visit thinknsk. THK offers consistent ultra-precision linear motion components and systems that deliver tight tolerances for our medical, lab automation and equipment manufacturing customers.
The confidence our customers have in the reliability and quality offered by THK makes us work even harder to innovate and achieve the ultimate in precision and quality. From the operating room to the manufacturing floor, Bimba offers a variety of pneumatic, electric and fluid control solutions to help you tackle your medical device applications. Whether you are designing a new system or improving an existing one, learn more about how our investment in medical device components can support your medical device needs at bimba.
Multiple connection manifolds provide a convenient junction point for the distribution of fluids or gases. Single or double solenoid operations internally piloted for high flow and lower power consumption.
FITTINGS Corrosion resistant stainless steel barbed and pushto-connect style fittings available in a wide variety of shapes and sizes for virtually any application. Managing Editor Nic Abraham nabraham wtwhmedia. Art Director Matthew Claney mclaney wtwhmedia.
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We offer more than 4, stock sizes in carbon and stainless steel. The medical device category covers a wide range of products, from 3D printing to design services, such as product development.
We especially appreciate feedback from our audience and always welcome more. Do you want more detail, or less? Also follow us on twitter at MedTechDaily. Clippard Clippar can provide just what you ar re looking for.
TTell us your needs. Clippard Instrument Laboratory, Inc. What is 3D printing? This contrasts to subtractive processes, such as the NC machining of traditional manufacturing, in which material is removed rather than being added.
An object is made in an additive manner by depositing successive layers of material until the entire object is built. Each layer can be visualized as a thinly sliced horizontal cross-section of the eventual object. It all starts with a digital or virtual design of the object you want to create, made with a 3D modeling program or by using a 3D scanner to copy an existing, usually hand-sculpted object.
The 3D scanner makes a 3D digital copy of the object that is used as the template for 3D printing. Hospitals and researchers are experimenting with 3D printers in hopes of printing human tissue and organs. What is automation? Automation is the use of equipment in a system of manufacturing or other production process that needs minimal human intervention. Automation can also be the use of a machine designed to follow a predetermined sequence of individual operations.
We make quick-turn prototypes and production parts including device handles, housings, strain reliefs and other components used in the medical industry. Got a project? What is prototyping? Prototyping is the process of building a model or early working version of a product.
A prototype is an original type, form, or instance of something serving as an example, basis or standard for other things of the same category. With over 40 years experience, superior capabilities. Call today for more information. Or visit us online at www. All rights reserved. Every day at Minnesota Rubber and Plastics we produce high tolerance medical components and assemblies for the most demanding applications. Our over 60 year history in the design and manufacture Precision Molded Medical Components and Assemblies.
Block 10, Unit A No. For a project evaluation call : Email requests to medical2 mnrubber. What is metalizing? Metalizing is a process that deposits a thin metallic film on the surface of a non-metallic object. Metalizing is a common coating process used to improve resistance to corrosion, wear, and fatigue.
What is nitinol and where is it used? That means nitinol can remember its original shape and return to it when heated. It also shows great elasticity under stress. What are high-performance polymers? Advanced Aluminum Solutions for Medical Device Development Building a better future means innovation and finding new ways to solve product design challenges. Extruded aluminum is already a part of many of the most exciting advances in healthcare.
With complete engineering and design assistance plus full fabrication capabilities at multiple locations across North America and the globe, Sapa can provide finished components for all of your needs. Contact us for more about Sapa and designing with aluminum!
Lamination is the technique of manufacturing a material in multiple layers, so that the composite material is stronger, more stable, and has sound insulation from the use of different materials. A laminate is often permanently assembled by heat, pressure, welding, or adhesives. When an item is given a plastic coating, it becomes tear-proof and waterproof because the laminating film encapsulates the item completely.
Polytetrafluoroethylene PTFE is a synthetic fluoropolymer of tetrafluoroethylene with numerous applications. It is a strong, tough, waxy, and nonflammable synthetic resin produced by the polymerization of tetrafluoroethylene.
PTFE is distinguished by its slippery surface, high melting point, and resistance to attack by almost all chemicals. It is used in a variety of products, including vascular grafts used to bypass obstructed blood vessels and grafts used for dialysis access. What is plating? Plating is a manufacturing process in which a thin layer of metal coats a substrate.
This is done through electroplating, which requires an electric current, or through electroless plating, an autocatalytic chemical process. Winco, Inc. Pictured is just a sampling of our products. Explore our full line at www.
What are adhesives? A brief classification of adhesives Adhesives are materials used to hold two surfaces together. An adhesive must wet the surfaces, adhere to the surfaces, develop strength after it has been applied, and remain stable.
The accompanying table classifies adhesives several ways. Paste, liquid, film, pellets, tape, and more Hot melt, reactive hot melt, thermosetting, pressure sensitive, contact, and more. The right partner can take you from concept to market faster. Meet Scapa Healthcare.
Our dedicated teams work with you every step of the way, from your earliest concept and product design through manufacturing and delivery. We design for manufacturing, building in process and product validations early on, so we can deliver high-quality products and rapid speed to market.
Device hacking — a new risk for medical device companies From the moment medical devices went wireless, the risk of cyber attacks became possible, theoretically. But when a diabetic stood on stage at a conference and hacked into his own insulin pump to change its settings, the medical device industry saw the risk become reality. Though the U. Food and Drug Administration has yet to see any reports of patient safety problems from hacked medical devices, a recent Information Week article notes that a U.
Department of Veteran Affairs study found incidents of medical devices being infected with malware over a two-year period. Moreover, the U. Department of Homeland Security has issued a warning that wireless networked medical devices are vulnerable to malicious intrusion and patient data theft. Data theft: Private health information, including medical identification numbers, can be stolen and misused.
The incentive is huge. However, devices with wireless capabilities to download patient data and upload software updates are vulnerable to hackers with malicious intent. At Travelers, we stay ahead of the curve on emerging risks and evolving threats by tracking developments in the field and monitoring expert opinions on the consequences to our customers. This information helps us shape products — like MedFirstSM — that are designed to protect medical device companies long before they face a claim for damages.
Medical device companies have a vital interest in protecting patients — but they also need to protect themselves. With MedFirst, companies can be confident that they have the right coverage, even in a wireless world.
The potential for medical device hacking makes building effective wireless security measures a high priority. It also means that companies need to be concerned about their own potential exposure to liability.
One Tower Square, Hartford, CT This material does not amend, or otherwise affect, the provisions or coverages of any insurance policy or bond issued by Travelers. It is not a representation that coverage does or does not exist for any particular claim or loss under any such policy or bond. Coverage depends on the facts and circumstances involved in the claim or loss, all applicable policy or bond provisions and any applicable law. Availability of coverage referenced in this document can depend on underwriting qualifications and state regulations.
CP Rev. What is a catheter? Medical catheters are tubes used in healthcare to deliver medications, fluids, or gases to patients, or to drain bodily fluids such as urine. Examples include vascular access devices or intravenous catheters, urinary catheters, and chest drainage tubes.
Catheters are generally inserted into a body cavity, duct, or blood vessel. They may be thin, flexible tubes called soft catheters or thicker and more inflexible catheters called hard catheters. A catheter that may be left in the body, whether temporarily or permanently, is referred to as an indwelling catheter. What is a balloon catheter? A balloon catheter incorporates a small balloon that may be introduced into a canal, duct, or blood vessel and then inflated to clear an obstruction or dilate a narrowed region to drain body fluids.
Drug-coated catheters, a more recent innovation, are designed to deliver anti-restenosis compounds like those used in drug-eluting stents. Merit Medical OEM offers thousands of quality components and innovative devices to meet your needs.
What is a stent? A stent is a wire mesh tube intended to prop open an artery. When made from stainless steel or nickel-titanium nitinol , stents are intended to be permanent. More recent stents are made of polymers designed to dissolve over a period of months.
Fatty deposits called plaque can build up in an artery and reduce the flow of blood. A complete blockages of blood flow to a part of the heart muscle results in a heart attack. Stents help keep coronary arteries open, reducing the chance of a heart attack. To open a narrowed artery, percutaneous coronary intervention or angioplasty may be used.
A balloon-tipped catheter is inserted into an artery and moved to the point of blockage. The balloon is inflated, compressing the plaque to restore flow. When the opening in the vessel has been widened, the balloon is deflated and the catheter withdrawn. During manufacturing, stents are collapsed over a balloon catheter. In a placement procedure, the balloon catheter-stent is moved into the area of blockage.
When the balloon is inflated, the stent expands and stays in place when the ballon is deflated and withdrawn, providing a scaffold to hold the artery open.
What is a guidewire catheter? A guidewire is a wire or spring that provides extra strength and stability during catheter placement and exchange during contralateral access the opposite side of the body on which a particular condition exists and in carotid procedures involving the two main arteries that carry blood to the head and neck. A guidewire also aids in catheter delivery. The finest miniature encoders for the most demanding spaces. Renishaw offers class-leading position encoders for precision motion control the world over.
With their exceedingly small dimensions and lightweight design this family of high performance sensors are ideal for applications with tight spaces and even tighter tolerances. Powerful magnetic and optical scale technology for uncompromising accuracy Exceptional dirt immunity and the highest signal stability. How are lasers used in medical manufacturing?
Medtech manufacturing has become more challenging as more functions and features are added to medical devices. There is a growing need for smaller devices with precise, high-quality, small features made with techniques beyond those found in traditional manufacturing.
Laser processing has been filling this need. Today, lasers routinely mark, cut, and drill various materials for the production of medical devices. As with most things related to human health, there are stringent requirements for materials and the methods used to process them.
Materials for which laser tools are selected tend to be of high strength, purity, and chemical resistance, often making them difficult to fabricate and process by other means.
Such materials must be extremely pure. In addition, their manufacturing processes, such as drilling and cutting, must be as clean as possible, leaving behind minimal debris and residue to cut down on costly and time-consuming postprocessing.
Laser tools in medtech manufacturing are dominated by high-averagepower CO2 and high-pulse-energy excimer designs. But as medical devices continue to shrink and become increasingly specialized, leading to lower production volumes, these lasers are proving unsuitable in some cases.
What is grinding? Grinding, a material removal and surface generation process, shapes and smooths finished components made of metal or other materials. Grinding employs an abrasive product, usually a rotating wheel, brought into controlled contact with a work surface. The grinding wheel is composed of abrasive grains held together in a binder. These abrasive grains act as cutting tools, removing tiny chips of material from the work piece. Ultrasonic welding is an industrial technique in which high-frequency acoustic vibrations are applied to workpieces held together under pressure to create a solid-state weld.
It is mostly used for plastics, and for joining dissimilar materials. High-frequency vibrations are applied to two parts or layers of material by a vibrating tool, such as a sonotrode or horn. Welding occurs as the result of heat generated at the interface between the parts or surfaces.
This technique is fast, efficient, non-contaminating, and requires no consumables. In addition to welding, ultrasonic processes can be used to insert, stake, stud-weld, degate, and spot-weld thermoplastics as well as seal, slit, and laminate thermoplastic films and fabrics. Ultrasonic components can be easily integrated into automated systems. What is stamping? Stamping, or pressing or sheet metal fabrication, is the process of placing flat sheet metal in either blank or coil form into a stamping press, where tool and die surfaces form the metal into a net shape.
Stamping includes a variety of manufacturing processes, such as punching, using a machine press or stamping press, blanking, embossing, bending, flanging, and coining. Sheet metal is metal formed into thin and flat pieces.
It is one of the main materials used in metalworking, and can be cut and bent into many different shapes. What is subtractive manufacturing?
Subtractive manufacturing, such as CNC milling and turning, removes material from a block or stock until only the required shape remains. Computer Numerical Controlled CNC or just NC for short machining describes end-toend component manufacturing that is highly automated, thanks to computer-aided design and manufacturing programs. A part starts as a digital CAD file, which is converted into the commands and toolpaths needed to produce the part in a particular machining center.
These commands dictate what tools to use and when to use them to cut the features of the required part. What is EDM? Electric Discharge Machining EDM , a metal-removal method, works when an electrical spark is created between an electrode and a workpiece. The spark is carefully controlled and localized so that it only affects the surface of the material. The EDM process does not usually affect the heat treatment below the surface. With wire EDM, the spark always takes place in a dielectric of deionized water.
The conductivity of the water is carefully controlled, making it an excellent environment for the EDM process. The flow of water also acts as a coolant and flushes away eroded metal particles. EDM wire cutting uses a metallic wire to cut a programmed and complex contour in a workpiece. Extrusion dies and blanking punches are often machined by wire cutting. Cutting is always through the entire work piece.
To start machining, it is first necessary to drill a hole in the workpiece or start from an edge. On the machined area, each discharge creates a small crater in the workpiece and an impact on the tool. The wire.
There is never a mechanical contact between the electrode and workpiece. The wire is usually made of brass or stratified copper, and is between 0. Depending on the needed accuracy and surface finish, a part will either be cut once or roughed and skimmed. On a one-cut, the wire ideally passes through a solid part and drops a slug or scrap piece when it is done. This gives adequate accuracy for some jobs, but most of the time, skimming is necessary.
A skim cut passes the wire back over the roughed surface with a lower power setting and low-pressure flush. There can be from one to nine skim passes, depending on the required accuracy and surface finish. Usually two skim passes are needed. A skim pass can remove as much as 0.
During roughing, the first cut, water is forced into the cut at high pressure to provide cooling and flush eroded particles as quickly as possible. During skimming, water is gently flowed over the burn so as not to deflect the wire. When it comes to reliability, nothing protects like Parylene.
Parylene is the ideal conformal coating for medical devices, implants and surgical tools. SCS Parylenes can be applied to virtually any material to create an ultra-thin, uniform, pinhole-free conformal coating with superior moisture, chemical and dielectric barrier properties. These coatings also provide a low coefficient of friction for applications where lubricity is a concern and they are biocompatible, biostable and sterilizable.
Contact SCS today for more information on using Parylene to assure the reliable performance of your medical products. What is injection molding? Injection molding makes parts by injecting heated and nearly liquid material usually plastic into a mold where it cools and holds a required shape. Plastic injection molding is a manufacturing process for producing thermoplastic and thermosetting polymer materials. It can be used to produce a variety of parts, from micro-sized components to complete medical devices.
Simple molds can be one-part devices in which a two-part material is poured. Parts required in high quantities and at tight tolerances are made in molds cut from tool steel and polished so that parts can be removed easily. Prototypes or noncritical parts may be formed in molds cut in aluminum to save time and test ideas.
A mold may have several cavities along with slides and screws that produce relatively complex parts. How are high-performance plastics used in medical devices? Prior to the development of high-performance plastics, many medical devices were heavier, more expensive, and ultimately less efficient than the equipment used today. Recent plastics and polymers have improved existing technologies, helped create new medical solutions, and are on the cutting edge of future devices.
So common are plastics in the medical industry that their presence in almost every facet of healthcare can easily go unnoticed. Child-proof locking systems for prescription pill bottles, tamper-evident seals, prosthetic limbs, surgical gloves, MRI and X-ray machines, all rely on plastics. Depending on the specific application, there are many different types of plastics created for medical needs. The basic composition for these materials begins with polymers.
Polymers are large macromolecules comprised of repeated subunits called monomers. Monomers chemically bind to each other to create polymer chains that are either linear, branched or cross-linked.
In linear polymers, such as polyvinyl chloride PVC , the molecular structure is a single, extended chain. Branched polymer materials tend to be stiffer than linear polymers. Cross-linked polymers, or network polymers, also have extensions; the difference is that these branches bond to other polymer chains. Thermoset plastics are an example of a cross-linked polymer. These materials are the building blocks of high-performance plastics. Thermal and radiation stabilizers, tougheners, plasticizers, antistats, and catalysts are just few additives used to optimize plastics for specific uses.
We specialize in permanent and bioresorbable materials. Our technology and innovation help customers achieve new product breakthroughs. I need a functional seal for a PCR tube with a ventilation channel in medical grade PVC and it must be produced in a clean room.
The parts you need. Caplugs engineers work with you to design a solution and ensure all your specs are met. Our comprehensive ISO quality management system offers the traceability, record retention and strict process controls needed to support your audit requirements. For more than 65 years, Caplugs has been the ideal choice for medical device protection and molded components. Twenty-five of the top 30 medical device manufacturers trust us with their critical projects.
Synthetic lubricants are artificially created compounds used primarily for reducing friction. In medical device applications, this friction reduction increases mechanical component life, reduces noise, and protects from dust and other external elements. Beyond this, synthetic lubricants can also act as a crucial component of the precision of a device.
Temperature range is also an important consideration for synthetic lubricants. While this holds true for the focusing mechanisms mentioned above, high-speed applications such as drills require the most attention to temperature ranges. Dental handpieces, for example, rotate at upwards of , rpm when polishing or drilling teeth.
The turbine that accelerates the rotating element contains a bearing that requires synthetic hydrocarbon oil lubrication. In addition to preventing contaminant damage at the micron level, the oil must also stand up to reuse protocol.
Dental handpieces are washed with cleanser, dried, relubricated and then sterilized in an autoclave. The high-temperature, high-pressure environment in an autoclave demands specialized oil. Synthetic lubricants are a broad category.
Different lubricants may have some overlap in performance characteristics, but correct lubrication is largely application-specific. Other medical applications for synthetic lubricants including laser controls, small motors, insulin pens and more. What is silicone molding? Injection molding with liquid silicone rubber LSR is a process capable of producing durable parts in high volume.
LSR molding is a thermoset process that mixes two components that are heat-cured in the mold using a platinum catalyst. An injection-molding process is used similar to conventional plastic injection molding, but the material delivery system is cooled while the mold is heated. LSR parts are considered strong and elastic with exceptional thermal, chemical, and electrical resistance.
Their physical properties also maintain at severe temperatures and withstand sterilization. Additionally, the parts are biocompatible and work well for products that come in contact with human tissue. Rubber molding is a process that creates a useable rubber part.
Rubber products are typically made from elastomers or uncured rubber. An elastomer is any material with sufficient resilience or memory for returning to its original shape in response to pressure or distortions. A wide variety of elastomers and rubber can be derived from natural sources, but are usually synthetic, produced through highly controlled chemical processes. In tasks that require materials to stretch and revert to their original shape, rubber work is about the best.
As another molding method, rubber molding injects a block of rubber into a metal cavity to create parts. The mold is then heated to activate a chemical reaction that will retain the shape of the mold. While there are method variations, the majority of rubber manufacturers use three types of heat and pressure for rubber molding. Those molding methods include rubber injection, compression, and transfer. What is dip molding?
Dip molding is any process in which a mold is dipped into a polymer for the purpose of molding a part. This process is ideal for caps, grips, formed parts, and more.
The rack is ideal for dipping in a mold-release agent to help remove a part, prior to preheating. The mandrels are then dipped into a plastisol material for a predetermined time.
Ready parts are cured, dip-quenched, and stripped off the mandrels. Providing High Speed Solutions In this industry, the demand for new products can rise in a heartbeat.
We specialize in complex, low volume plastic injection molding. We can design, engineer and manufacture any part to your specifications and deliver it in record time — without ever missing a beat. To learn more, call What are disposable devices?
A disposable device is any medical apparatus intended for one-time or temporary use. Medical and surgical device manufacturers worldwide produce many types of disposable devices. Examples include hypodermic needles, syringes, applicators, bandages and wraps, drug tests, exam gowns, face masks, gloves, suction catheters, and surgical sponges.
The primary reason for creating disposable devices is infection control. When an item is used only once, it cannot transmit infectious agents to subsequent patients. One might think the most important factor in the design of single-use products is cost, but disposable medical devices require a careful balance between performance, cost, reliability, materials, and shelf life.
Plastics are often used in the manufacturing of disposables because they are relatively inexpensive and there are many different types. In a device such as a syringe that must undergo extreme pressure, polycarbonates are used because of their strength. PVC can also. Reusable devices, on the other hand, are typically made of more costly, sturdier materials such as ceramics or steel. Disposable-device assembly depends primarily on injection-molded plastic, assembled by bonding, gluing, ultrasonic welding or radio-frequency welding.
The high production volume of single-use devices calls for an automated assembly in clean rooms to minimize human contact. Unlike reusable devices, which are often sterilized at the healthcare facility, disposable devices are sterilized before leaving the manufacturing site. The device and packaging must be designed to accommodate sterilization.
But before medical devices can be reprocessed and reused, a third-party or hospital reprocessor must comply with the same requirements that apply to original equipment manufacturers, according to FDA regulations.
So when we bring your medical device to life, we infuse stringent quality standards into every step. Our arsenal of quality tools includes ISO certifications,. Making quality a priority is just one of the hallmarks of Tegra Medical, along with providing solutions, speed and service for our customers.
Boston — Memphis — Costa Rica www. What is heat treating? A heat treatment process heats and cools metals to alter their physical and mechanical properties without changing their shape.
The process uses extreme temperatures to achieve the required results. Heat treatment is typically a method for strengthening materials, but it can also change some mechanical properties, such as improved formability and machining. The process is most commonly used in metallurgy, but heat treatment is also used in the manufacture of glass, aluminum, and steel. Web Industries takes the mystery out of commercializing your medical devices.
Our automated high-volume IVD and LFI manufacturing, assembly, and packaging solutions make the pain of bringing your tests to market disappear. We understand the unique challenges of being a medical CMO, and we know what it takes to get medical devices right every time. Contact us to make your next product launch a success.
Electropolishing is an electrochemical process similar to electroplating, but in reverse. Electropolishing smooths and streamlines the microscopic surface of a metal object, such as , or series stainless steel. The resulting surface is microscopically featureless, with no torn surface remaining. In electropolishing, material is removed ion by ion from the surface of the metal being polished.
The fundamental principles of electrolysis and electrochemistry replace traditional mechanical finishing techniques, including grinding, milling, blasting, and buffing as the final finish. In basic terms, the metal object to be electropolished is immersed in an electrolyte and subjected to a direct electrical current. The metal object is maintained anodic, with the cathodic connection being made to a nearby metal conductor. In addition, the polarized surface film is exposed to the combined effects of oxygen gassing.
This occurs with the removal of electrochemical metal, saturation of the surface with dissolved metal, and the agitation and temperature of the electrolyte. What are minimally invasive devices?
Minimally invasive surgery refers to surgical techniques that limit the size of incisions needed, or has a short recovery time. When a medical device is placed within a patient during such a surgery, it is a minimally invasive device.
Many procedures involve the use of arthroscopic or laparoscopic devices, and remotecontrol manipulation of instruments with indirect observation through an endoscope or large display panel.
The surgery is usually carried out through the skin or through a small body cavity or anatomical opening and can involve a robot-assisted system. What is single-use manufacturing? Single-use manufacturing, or more clearly manufacturing single-use devices, emerged about the mids and stemmed from single-use systems which were gaining wider use in the pharmaceuticals industry, in particular for the production of specialized drugs.
Single-use manufacturing now involves the production of relatively complex disposable devices used in surgical procedures such as electrosurgery. Razor blades and their holders are another example. Such devices are usually complex items intended for a single use, as opposed to simple disposables. They are examples of relatively simple singleuse products. At first, the bags replaced glass bottles and soon became available with a plastic tube or two, connectors, valves, and vials for taking samples.
More complex disposable products are used in systems for specialized or boutique drug production and may include disposable filters, electronics, and sensors. The alternative to single-use systems, to follow the drug example, would be processes made of relatively inflexible stainless-steel vessels and reactors, hard piping, valves, and so on.
Such a fixed system must be cleaned and sterilized, a relatively labor- and energy-intensive operation. Single-use devices, by one calculation, are more cost-effective and faster to implement. Other advantages of single-use systems include: www.
They reduce capital expenditures and require less facility space. Single-use systems are adaptable to patient-proximity manufacturing, a consideration for epidemic and bioterrorism vaccine deployment.
Single-use systems reduce the need for the steam, hot water, ultra-pure water, and chemicals used to clean stainless steel components, and eliminate the need to revalidate conventional equipment.
Single-use systems reduce the possibility of cross contamination while improving sterility assurance. More qualified vendors are ready to provide timely supply and service of components and systems. Less time is spent in changeovers for batch-to-batch and product-to-product.
In addition, some single-use systems are delivered gamma-sterilized and pre-qualified by the supplier. What do ratcheting devices do on surgical tools? A ratchet mechanism on a medical tool is a step-locking device. In one application, as the handles of a clamping mechanism are closed, its jaws also close and the ratchet holds them in a locked position.
The ratchet consists of a notched bar on each handle, the notches facing and overriding when the handles are closed. What methods are used to join materials? The joining of materials is an important technology in many manufacturing industries. Most products, machines or structures are assembled and fastened from parts, and the joining of these parts may be achieved through rivets, seaming, clamping, soldering, brazing, welding and the use of adhesives.
With continuing advances in the medical industry, medical devices are becoming increasingly complicated. Such devices are usually comprised of components and materials that must be joined in some way, whether used outside the body, in the case of instruments and surgical tools, or inside the body, for diagnostic or therapeutic purposes. To create highly reliable devices, one must choose which joining process is appropriate at every step. Many factors influence those choices, from production economics, to mechanical properties such as strength, vibration damping and durability, corrosion or erosion resistance, as well as the ability to correct defects.
Joining processes are typically divided into three categories: Mechanical joining, welding, and adhesive bonding. Medical devices are manufactured using a variety of materials, from metals to polymers to ceramics, and can be joined using all three methods. Mechanical joining is a process for joining parts through clamping or fastening using screws, bolts or rivets. Advantages of mechanical joining include versatility, ease of use, and the option to dismantle the product in cases where regular maintenance requires it.
The ability to join dissimilar materials is another benefit. A drawback of using mechanical joining is the lack of a continuous connection between parts, because the joint is achieved through discrete points. Also, holes created for joining are vulnerable to fractures and corrosion. Welding includes fusion welding, brazing and soldering, and solid-state welding.
In fusion welding, melting and solidification occur in the zone being joined. For metals and plastics, both the work pieces and the filler material experience melting.
Brazing and soldering join materials by adding a melted filler material between the joined surfaces. Solid-state welding requires no melting of base of filler materials, because it only involves plastic deformation and diffusion. Adhesive bonding joins parts using bonding chemicals. This process may be used to join polymers and polymermatrix composites, as well as polymer-to-metal, metal-to-metal, and ceramic-to-metal.
In this method of joining, joints can withstand shear, tensile and compressive stresses, but do not have good resistance to peeling. What is contract manufacturing? Contract manufacturing is a process that establishes a working agreement between two companies. As part of the agreement, one company custom-produces parts or other materials on behalf of the client. In most cases, the manufacturer also handles ordering and shipment schedules.
As a result, the client does not have to maintain manufacturing facilities, purchase raw materials, or hire labor to produce the finished products. The basic working model used by contract manufacturers translates well into many different industries. There are many contract manufacturers in pharmaceuticals, as well as food production, and the creation of computer components and other forms of electronics.
Even industries such as personal care and hygiene products, automotive parts, and medical supplies are often produced under the terms of a contract-manufacturing agreement. What are electromechanical devices? Almost any single device with an electrical and mechanical component can be referred to as electromechanical EM. You might even call an electric motor an electromechanical device, because it turns electricity into rotary mechanical motion.
Also, a controller somewhere in the design governs the functions of the EM device. A brief Controller section accompanies this discussion. Presently, few EM devices, other than mechanical hearts or cardiac assist devices, are implantable, but that will change.
A trend in the design of a few EM devices is toward miniaturization, to make them as unobtrusive as possible, either for healthcare setting or as wearable units. Exploring a few examples of EM devices can sketch the landscape of the variations available.
Consider a particular AC-powered electric actuator that operates from to Vac. It comes with positioning electronics to define the limits of the motion that are UL Listed, which means that device meets UL safety standards.
The actuators combine a brushless servomotor with either rotary or linear output actuation and digital position control. Electromechanical cylinders although they are not cylindrical give users control over positioning accuracy, axial thrust, torque, and speed, providing more flexibility to applications that traditionally use hydraulic or pneumatic cylinders.
The devices use a precision-rolled, ball-screw actuator that ensures high positioning accuracy and repeatability, and eliminates the stick-slip effect. To give an idea of what is available from such cylinders, the units from one manufacturer come in six sizes with stroke lengths to 2,mm and speeds to 1. Each unit is rated to an IP65 level of protection. As you can imagine, the quality of EM devices spans a range. Those with a rating of IP65 International Protection are protected against solids, objects, and water.
The 6 indicates protection against dust, while the 5 indicates protection against liquids and low-pressure jets of water from all directions. A second example of an EM device is a linearactuator line that includes explosion-proof devices. The linear actuator meets ATEX EU directives for explosion-proof equipment requirements for use in potentially explosive atmospheres, such as high-oxygen areas. These servo-electromechanical systems are said to offer a clean, fast, simple, and cost-effective alternative to hydraulics and longer life compared to pneumatics.
For a third example, consider the gripper, a device often used with pick-and-place robotic systems. Fingered tooling, or jaws, attach to the grippers to hold an object. They come in a variety of styles and powered designs.
Three common types are parallel two-fingered , three-fingered, and angled designs. The most common are parallel designs, with two fingers that close on a workpiece to grip it, or open out to create contact friction on an inside surface.
Three-finger designs hold the workpiece in the center. What is product development? Product development is the process of designing, creating, and marketing a product. The procedure mainly focuses on developing systematic methods for guiding all the processes involved in getting a cutting-edge product to market.
The product development process can involve improving an existing. Continual product development is necessary for companies striving to keep up with innovation and technology to ensure future profitability and success.
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A motion controller governs the motion and position of an object on a machine axis. A properly functioning machine also requires motors or fluid-power cylinders for motive power, sensors for judging position and speed, a computer to store and execute rules that govern the motion and other conditions, and a network for taking in sensor signals and outputting command signals.
For further discussion of linear guides, motors, and sensors, see the accompanying sections. Motion controllers are often implemented using computers, but it is also possible to control motion with analog devices.
Most medical applications for motion controllers are on manufacturing equipment and patient-assist devices. A simple and inexpensive controller might be a single-chip microcontroller running a real-time operating system. Windows-based application development software may provide a setup wizard to shorten installation and evaluation time.
This could be appropriate for a simple one- or two-axis medical device. A large manufacturing machine, however, would require something that can handle more inputs, make decisions quickly, and provide appropriate outputs, such as alarms when something goes wrong. The variety of available controllers is considerable. At the physical level, most motion controllers are stand-alone versions based on PCs, or are microcontrollers built into equipment.
Stand-alone controllers are complete systems that include all electronics, power supplies, and external connections which all mount in a physical enclosure. PC-based controllers can resemble the motherboard of a basic personal computer or a ruggedized industrial PC,. In addition, the controller interfaces with lab and clean-room devices, and other equipment. One big plus for PC-based controllers is that they provide a readymade graphical user interface for easier programming and tuning.
In fact, work on the Poisson distribution is by no means a matter of the past. Discussing and testing various distribution models, Rothschild did not find any one of the models he tested to be adequate. As was said above, Michel first found the lognormal distribution to be a completely inadequate model. He then tested the 1-displaced Poisson distribution and obtained negative results as well: although fitting the Poisson distribution led to better results as compared to the lognormal distribution, word length in his data turned out not to be Poisson distributed, either Michel f.
Finally, Grotjahn whose work will be discussed in more detail below cf. In doing so, let us first direct our attention to the 2-parameter model suggested by him, and then to his 3-parameter model. In a similar way, two related 2-parameter distributions can be derived from the general model 2.
It is exactly the latter distribution 2. Fucks has not systematically studied its relevance; still, it might be tempting to see what kind of results are yielded by this distribution for the data already analyzed above cf. As in the case of the 1-displaced Poisson distribution, one has thus to ac- knowledge that the Fucks 2-parameter 1-displaced Dacey-Poisson distribution is an adequate theoretical model only for a specific type of empirical distribu- tions.
This leads to the question whether the Fucks 3-parameter distribution is more adequate as an overall model. It would lead too far, here, to go into details, as far as their derivation is concerned. Consequently, three solutions are obtained, not all of which must necessarily be real solutions. With this in mind, let us once again analyze the data of Table 2. The results obtained can be seen in Table 2. It can clearly be seen that in some cases, quite reasonably, the results for the 3-parameter model are better, as compared to those of the two models discussed above.
From the results represented in Table 2. These violations can be of two kinds: a. However, some of the problems met might be related to the specific way of estimating the parameters suggested by him, and this might be the reason why other authors following him tried to find alternative ways. Cercvadze, G. As opposed to most of his German papers, Fucks had discussed his generalization at some length in this English synopsis of his work, and this is likely to be the reason why his approach received much more attention among Russian-speaking scholars.
We need not go into details, here, as far as the derivation of the Fucks dis- tribution and its generating function is concerned cf. Unfortunately, Piotrovskij et al. Based on the standard Poisson distribution, as represented in 2. Based on these assumptions, the following special cases are obtained for 2. These analyses comprised nine Polish literary texts, or segments of them, and the results of these analyses indeed proved their approach to be successful.
For the sake of comparison, Table 2. A closer look at these data shows that the Polish text samples are relatively homogeneous: for all texts, the dispersion quotient is in the interval 0.
The authors analyzed Croatian data from two corpora, each consisting of several literary works and a number of news- paper articles. The data of one of the two samples are represented in Table 2. Frequency observed Poisson 0 1 2 3 4 5 6 7 8 Syllables per word Figure 2. Rather, it is of methodological interest to see how the authors dealt with the data. Guided by the conclusion supported by the graphical representation of Figure 2.
Still, there remain at least two major theoretical problems: 1. No interpretation is given as to why the weighting modification is necessary: is this a matter of the specific data structure, is this specific for Croatian language products? As the re-analyses presented in the preceding chap- ters have shown, neither the standard Poisson distribution nor any of its straight forward modifications can be considered to be an adequate model. Grotjahn, in his attempt, opened the way for new perspectives: he not only showed that the Poisson model per se might not be an adequate model; fur- thermore, he initiated a discussion concentrating on the question whether one overall model could be sufficient when dealing with word length frequencies of different origin.
As a starting point, Grotjahn analyzed seven letters by Goethe, written in , and tested in how far the 1-displaced Poisson distribution would prove to be an adequate model. As was pointed out above cf. However, of the concrete data analyzed by Grotjahn, only some satisfied this condition; others clearly did not, the value of d ranging from 1. In a way, this conclusion paved the way for a new line of research.
After decades of concentration on the Poisson distribution, Grotjahn was able to prove that this model alone cannot be adequate for a general theory of word length distribution. On the basis of this insight, Grotjahn further elaborated his ruminations. Although every single word thus may well follow a Poisson distribution, this assumption does not necessarily imply the premise that the probability is one and the same for all words; rather, it depends on factors such as linguistic context, theme, etc.
Grotjahn 56ff. Thus, the so-called negative binomial distribution 2. Therefore, as Grotjahn 71f. With his approach, Grotjahn thus additionally succeeded in integrating earlier research, both on the geometric and the Poisson distributions, which had failed to be adequate as an overall valid model.
The data are reproduced in Table 2. Poisson d. The results are graphically repre- sented in Figure 2. History and Methodology of Word Length Studies 65 f x neg. Poisson 0 1 2 3 4 5 6 7 8 9 Figure 2. Still, it is tempting to see in how far the negative binomial distribution is able to model the data of nine languages, given by Fucks cf.
Their discussion is of unchanged importance, still today, since many more recent studies in this field do not seem to pay sufficient attention to the ideas expressed almost a decade ago. Before discussing these important reflections, one more model should be discussed, however, to which attention has recently been directed by Kromer a,b,c; In this case, we are concerned with the Poisson-uniform distribution, also called Poisson-rectangular distribution cf.
In his approach, Kromer a derived the Poisson-uniform distribution along a different theoretical way, which need not be discussed here in detail.
With regard to formula 2. It would be too much, here, to completely derive the two relevant equa- tions anew. It may suffice therefore to say that the first equation can easily be derived from 2. Best, in turn, had argued in favor of the negative binomial distribution discussed above, as an adequate model. The results obtained for these data need not be presented here, since they can easily be taken from the table given by Kromer a: These data have been repeatedly analyzed above, among others with regard to the negative binomial distribution cf.
Using the method of moments, it turns out that in four of the nine cases Esperanto, Arabic, Latin, and Turkish , no acceptable solutions are obtained. Now, what is the reason for no satisfying results being obtained, according to the method of moments? Empirically, this is proven by the results represented in Table 2. History and Methodology of Word Length Studies 71 Poisson-uniform distribution suggested by Kromer personal communication shall be demonstrated here; it is relevant for those cases when parameter a con- verges with parameter b in equation 2.
Parameter I, according to him, expresses something like the specifics of a given language i. Unfortunately, most of the above-mentioned papers Kromer b,c; have the status of abstracts, rather than of complete papers; as a consequence, only scarce empirical data are presented which might prove the claims brought forth on a broader empirical basis. If his assumption should bear closer examination on a broader empirical basis, this might as well explain why we are concerned here with a mixture of two distributions.
However, one must ask the question, why it is only the rectangular distribution which comes into play here, as one of two components. Strangely enough, it is just the Poisson-uniform distribution, which converges to almost no other distribution, not even to the Poisson distribution, as can be seen above for details, cf. This discussion was initiated by Grotjahn and Altmann as early as in , and it seems impor- tant to call to mind the most important arguments brought forth some ten years ago.
Yet, only recently systematic studies have been un- dertaken to solve just the methodological problems by way of empirical studies. Nevertheless, most of the ideas discussed — Grotjahn and Alt- mann combined them in six groups of practical and theoretical problems — are of unchanged importance for contemporary word length studies, which makes it reasonable to summarize at least the most important points, and comment on them from a contemporary point of view.
The problem of the unit of measurement. In other words: There can be no a priori decision as to what a word is, or in what units word length can be measured. Meanwhile, in contemporary theories of science, linguistics is no exception to the rule: there is hardly any science which would not acknowledge, to one degree or another, that it has to define its object, first, and that constructive processes are at work in doing so.
The relevant thing here is that measuring is made possible, as an important thing in the construction of theory. What has not yet been studied is whether there are particular dependencies between the results obtained on the basis of different measurement units; it goes without saying that, if they exist, they are highly likely to be language- specific.
Also, it should be noted that this problem does not only concern the unit of measurement, but also the object under study: the word. It is not even the problem of compound words, abbreviation and acronyms, or numbers and digits, which comes into play here, or the distinction between word forms and lexemes lemmas — rather it is the decision whether a word is to be defined on a graphemic, orthographic-graphemic, or phonological level.
The population problem. Again, as to these questions, there are hardly any systematic studies which would aim at a comparison of results obtained on an empirical basis. However, there are some dozens of different types of letters, which can be proven to follow different rules, and which even more clearly differ from other text types.
The goodness-of-fit problem. Rather, the question is, what is a small text, and where does a large text start? History and Methodology of Word Length Studies 75 d. The problem of the interrelationship of linguistic properties. What they have in mind are in- tralinguistic factors which concern the synergetic organization of language, and thus the interrelationship between word length factors such as size of the dictionary, or the phoneme inventory of the given language, word frequency, or sentence length in a given text to name but a few examples.
As soon as the interest shifts from language, as a more or less abstract system, to the object of some real, fictitious, imagined, or even virtual communicative act, between some producer and some recipient, we are not concerned with language, any more, but with text. Consequently, there are more factors to be taken into account forming the boundary conditions, factors such as author- specific, or genre-dependent conditions.
Ultimately, we are on the borderline here, between quantitative linguistics and quantitative text analysis, and the additional factors are, indeed, more language-related than intralinguistic in the strict sense of the word. It should be mentioned, however, that very little is known about such factors, and systematic work on this problem has only just begun.
The modelling problem. As can be seen, the aim may be different with regard to the particular research object, and it may change from case to case; what is of crucial relevance, then, is rather the question of interpretability and explanation of data and their theoretical modelling.
The problem of explanation. Consequently, in order to obtain an explanation of the nature of word length, one must discover the mechanism generating it, hereby taking into account the necessary boundary conditions. Thus far, we cannot directly concentrate on the study of particular boundary conditions, since we do not know enough about the general system mechanism at work. Consequently, contemporary research involves three different kinds of orientation: first, we have many bottom-up oriented, partly in the form of ad-hoc solutions for particular problems, partly in the form of inductive research; second, we have top-down oriented, deductive research, aiming at the formulation of general laws and models; and finally, we have much exploratory work, which may be called abductive by nature, since it is characterized by constant hypothesis testing, possibly resulting in a modification of higher-level hypotheses.
In this framework, it is not necessary to know the probabilities of all individual frequency classes; rather, it is sufficient to know the relative difference between two neighboring classes, e. Ultimately, this line of research has in fact provided the most important research impulses in the s, which shall be discussed in detail below. In their search for relevant regularities in the organization of word length, Wimmer et al.
Wimmer et al. This model was already discussed above, in its 1-displaced form 2. It has also been found to be an adequate model for word length frequencies from a Slovenian frequency dictionary Grzybek After corresponding re-parametrizations, these modifications result in well-known distribution models. In , Wimmer et al. The set of word length classes is organized as a whole, i.
Now, different distributions may be inserted for j. Thus, inserting the Borel distribution cf. The parameters a and b of the GPD are independent of each other; there are a number of theoretical restrictions for them, which need not be discussed here in detail cf.
Irrespective of these restrictions, already Wimmer et al. These observations are supported by recent studies in which Stadlober analyzed this distribution in detail and tested its adequacy for linguistic data. Stadlober As can be seen, the results are good or even excellent in all cases; in fact, as opposed to all other distributions discussed above, the Consul-Jain GPD is able to model all data samples given by Fucks.
It can also be seen from Table 2. In this respect, i. As to this problem, it seems however important to state that this is not a problem specifically related to the GPD; rather, any mixture of distributions will cause the very same problems. In this respect, it is important that other distributions which imply no mixtures can also be derived from 2. It would go beyond the frame of the present article to discuss the various extensions and modifications in detail here.
As a result, there seems to be increasing reason to assume that there is in- deed no unique overall distribution which might cover all linguistic phenom- ena; rather, different distributions may be adequate with regard to the material studied. This assumption has been corroborated by a lot of empirical work on word length studies from the second half of the s onwards. Best More often than not, the relevant analyses have been made with specialized software, usually the Altmann Fitter.
This is an interactive computer pro- gram for fitting theoretical univariate discrete probability functions to empirical frequency distributions; fitting starts with the common point estimates and is optimized by way of iterative procedures.
There can be no doubt about the merits of such a program. Now, the door is open for inductive research, too, and the danger of arriving at ad-hoc solutions is more virulent than ever before. What is important, therefore, at present, is an abductive approach which, on the one hand, has theory-driven hypotheses at its background, but which is open for empirical findings which might make it necessary to modify the theoretical assumptions.
In addition to the C values of the discrepancy coefficient, the values for parameters a and b as a result of the fitting are given. As can be seen, fitting results are really good in all cases. As to the data analyzed, at least, the hyper-Poisson distribution should be taken into account as an alternative model, in addition to the GDP, suggested by Stadlober Comparing these two models, a great advantage of the GPD is the fact that its reference value can be very easily calculated — this is not so convenient in the case of the hyper-Poisson distribution.
On the other hand, the generation of the hyper-Poisson distribution does not involve any secondary distribution to come into play; rather, it can be directly derived from equation 2. In its 1-displaced form, equation 2. To summarize, we can thus state that the synergetic approach as developed by Wimmer et al.
Generally speaking, the authors understand their contribution to be a logical extension of their synergetic approach, unifying previous assumptions and empirical findings. The individual hypotheses belonging to the proposed system have been set up earlier; they are well-known from empirical research of the last decades, and they are partly derived from different approaches.
Specifically, Wimmer et al. History and Methodology of Word Length Studies 85 it is confined to the first four terms of formula 2. Many distributions can be derived from 2. It can thus be said that the general theoretical assumptions implied in the synergetic approach has experienced strong empirical support. One may object that this is only one of possible alternative models, only one theory among others.
However, thus far, we do not have any other, which is as theoretically sound, and as empirically supported, as the one presented.
On the other hand, hardly any systematic studies have been undertaken to empirically study pos- sible influencing factors, neither as to the data basis in general i. Ultimately, the question, what may influence word length frequencies, may be a bottomless pit — after all, any text production is an historically unique event, the boundary conditions of which may never be reproduced, at least not completely. Still, the question remains open if particular factors may be detected, the relevance of which for the distribution of word length frequencies may be proven.
This point definitely goes beyond a historical survey of word length studies; rather, it directs our attention to research desires, as a result of the methodolog- ical discussion above. A, ; — Best, Karl-Heinz ed. Brainerd, Barron Weighing evidence in language and literature: A statistical approach. Chebanow Chebanow, S. Dewey, G. Cambridge; Mass.
Elderton, William P. London, Fucks, Wilhelm Nach allen Regeln der Kunst. Leningrad, Nauka: — Dordrecht, NL. Grzybek, Peter ed. Ljubljana etc. The Impact of Word Length. Kromer, Victor V. Materialy konferencii. Ma- terialy konferencii. Markov, Andrej A. Mendenhall, Thomas C. Studien zum 1. Internationalen Bulgaristikkongress Sofia Piotrovskij, Rajmond G.
Williams, Carrington B. Wimmer, Gejza; Altmann, Gabriel Thesaurus of univariate discrete probability distributions. Zerzwadse, G. In: Grundlagenstudien aus Kybernetik und Geisteswissenschaft 4, — The idea is derived from the Fitts—Garner controversy in mathematical psychology cf. Fitts et al. Obviously, the problem is quite old but has not penetrated into linguistics as yet. A word in a text can be thought of as a realization of a number of different alternative possibilities, see Fig.
They can even be understood in different ways, e. What is neglected when correlating the lengths and the frequencies of words in real texts is the fact that for the text producer there is not at all free choice of all existing words at every moment. Trying to fill in the blank is a model for determining the uncertainty of the missing word. It must be noted that SIC or HIC are associated not only with words but also with whole phrases or clauses, so that they represent rather polystratic structures and sequences.
The present approach is the first approximation at the word level. Preparation In order to illustrate the variables which will be treated later on, let us first define some quantities.
The cardinality of the set X will be symbolized as X. P the set of positions in a text, whatever the counting unit. The elements of this set are tokens tijk , i.
If the type and its token are known, the indices i and j can be left out. The elements of this set, aij , are not necessarily synonyms but in the given context they are admissible alternatives of the given token.
The index k can be omitted Aij the number of elements in the set Aij , i. This entity can be called tokeme. By defining Mij , we are able to distinguish between tokens of the same type but with different alternatives and different number ai — so they are different tokemes. Example Using Table 9 cf. The text is reproduced word for word in the second column of Table 9 p.
The length is measured in terms of the number of syllables of the word. Thus, e. We can define it for types too: then it is the mean of all LLs of all tokens of this type in the text. LL is usually a positive real number. The errors compensate each other in the long run, so the distribution of L equals that of LL.
It can be ascertained for any text. We can set up the hypothesis that Hypothesis 1 The longer the token, the longer the tokeme at the given position. This hypothesis can be tested in different ways. As an empirical consequence of hypothesis 1 it can be expected that the distribution of L and LL is approximately equal.
A token of length L has alternatives which are on average the same length, i. Since LL is a positive real number it is an average we divide the range of lengths in the text in continuous intervals and ascertain the number of cases the frequency in the particular intervals.
This can easily be made using the third and the sixth column of Table 9 p. The result is presented in Table 3. It can easily be shown that the frequencies differ non-significantly. Since the distributions are equal, they must abide by the same theoretical distribution.
Using the well corroborated theory of word length cf. Wim- mer et al. As a matter of fact, for the distribution of LL we take the middles of the intervals as variable. It would, perhaps, be more correct to use for both data the continuous equivalent of the geometric distribution, namely the exponential distribution — however, again not quite correct. Thus we adhere to discreteness without loss of validity. The result of fitting the geometric distribution to the data from Table 3.
Length range in tokemes In each tokeme the lengths of words local latent lengths are distributed them- selves in a special way. It is not fertile to study them individually since the majority of them is deterministic i. It is more prolific to consider the ranges of latent lengths for the whole text. For this phenomenon we set up the hypothesis Hypothesis 2 The range of latent lengths within the tokemes is geometric-Poisson. Since the latent length distribution LLx is geometric and each LLx is al- most identical on average with that of Lx the alternatives tend to keep the length of the token , the range of the latent lengths in the tokeme is very restricted.
The deviations seem to be distributed at random, i. Evidently, the fitting is very good and corroborates in addition hypothesis 1, too. Thus latent length is a kind of latent mechanism controlling the token length at the given position. Latent length is not directly measurable, it is an invisible result of the complex flow of information. Nevertheless, it can be made visible — as we tried to do above — or it can be approximately deduced on the basis of token lengths.
Information Content of Words in Texts 99 Table 3. Stable latent length Consider the deviations of the individual token lengths from those of the re- spective tokeme lengths as shown in Table 9 p.
This encourages us to set up the hypothesis that Hypothesis 3 There is no tendency to choose the smallest possible alternative at the given position in text. The hypothesis can easily be tested.
SIC of the text Above, we defined SIC of a type as the dual logarithm of the mean size of all tokeme sizes of the given type, as shown in formula 3. Two possibilities can be proposed. We shall use here 3. For the given text it can be computed directly using the fifth column of Table 9 p. We suppose that it is the smaller the more formal the text.
We can build about it a confidence interval. Here the tokeme sizes build a sequence of a 1, 16, 3, 2, 1, 8, 2, 1,. Taking the dual logarithms we obtain a new sequence b 0, 4, 1. In order to control the information flow and at the same time to allow licentia poetica, zeros and non-zeroes must display some pattern which is characteristic of different text types. Thus we obtain the two state sequence c 0, 1, 1, 1, 0, 1, 1, 0,.
We begin with the examination of runs of 0 and 1 and set up the hypothesis that Hypothesis 4 The building of text blocks with zero uncertainty 0 and those with selection possibilities 1 is random i.
In practice it means that the runs of zeroes and ones are distributed at random. In our text see Table 9 , p. Another possibility is to consider sequence c as a two-state Markov chain or sequences a and b as multi-state Markov chains.
In the first approx- imation we consider case c as a dynamical system and compute the transition matrix between zeroes and ones. Taking the powers of the above matrix we can easily see that the probabilities are stable to four decimal places with P 4 yielding a matrix with equal rows [0. Since P n represents the n-step transition prob- ability matrix, the exponent n is also a characteristic of the text. Alternatives, length and frequency Since SIC has not been imbedded in the network of synergetic linguistics as yet, it is quite natural to ask whether it is somehow associated with basic language properties such as length and frequency.
In the present paper all other properties e. The data for testing can easily be prepared using Table 9 p. Below we show merely lengths 4 and 5 because the full Table is very extensive cf. Table 3. This results in Table 3. In such cases they must be taken into account explicitly. In our case this leads to partial differential equations.
Let us assume that length has a constant effect, i. Fitting this curve to the data in Table 3. This is, of course, merely the first approximation using data smoothing because the text was rather a short one. Interpretation and outlook Looking at Tables 3. But we recognize that the influence of frequency is considerably weaker than that of length. If we regard 3. The direction of this influence is even more astonishing: with increasing length the number of alternatives is increasing too, longer words are more often freely chosen, while one perhaps would expect a preference for choosing shorter words.
Since the e-function plays an important role in psychology, for example in cognitive tasks like decision making, we suppose that word length is a variable which is connected with some basic cognitive psychological processes. Andersen, S. Attneave, F. New York. Berlyne, D. Coombs, C. Englewood Cliffs, N. Evans, T. Fitts, P. Garner, W. Hartley, R. Piotrowski, R.
Wimmer, G. June 21—23, , Graz University. Bahnhof 2 – 1 2. Altona 3 – 1 3. Kinderbuch 3 – 1 3. Stiftung 2 – 1 2. Deutschland 2 – 1 2. Kinder- 2 – 1 2. Krimi 2 Kriminalroman, Thriller 3 3. Kinderbuchautor 5 Autor, Schriftsteller, Kinderbuchschriftsteller 4 4. Andreas 3 – 1 3. Anfang 2 Beginn, Start 3 1. Jungen 2 – 1 2. Weltuhr 2 Uhr 2 1. Seiten 2 – 1 2. Aktion 3 Leistung, Tat, Sache 4 2. Guinness 2 – 1 2. Rekorde 3 – 1 3. Altona 3 Hamburg 2 2. Bahnhofshalle 4 Halle, Vorhalle, Wandelhalle 4 3.
Szenen 2 Bilder, Teile, Partien 4 2. Detektive 4 – 1 4. Introduction This paper concentrates on the question of zero-syllable words i. As an essential result of these studies it turned out that, due to the specific structure of syllable and word in Slavic languages a several probability distribution models have to be taken into account, and this depends b on the fact if zero-syllable words are considered as a separate word class in its own right or not.
Predominantly putting a particular accent on zero-syllable words, we examine if and how the major statistical measures are influenced by the theoretical definition of the above- mentioned units.
We do not, of course, generally neglect the question if and how the choice of an adequate frequency model is modified depending on these pre-conditions — it is simply not pursued in this paper which has a different accent. Basing our analysis on Slovenian texts, we are mainly concerned with the following two questions: a How can word length reasonably be defined for automatical analyses, and b what influence has the determination of the measure unit i.
Thus, subsequent to the discussion of a , it will be necessary to test how the decision to consider zero-syllable words as a specific word length class in its own right influences the major statistical measures. Any answer to the problem outlined should lead to the solution of specific prob- lems: among others, it should be possible to see to what extent the proportion of x-syllable words can be interpreted as a discriminating factor in text typology — to give but one example.
In a way, the scope of this study may be understood to be more far-reaching, however, insofar as it focuses relevant pre-conditions which are of general methodological importance. For these ends, we will empirically test, on a basis of Slovenian texts, which effects can be observed in dependence of diverging definitions of these units.
Word Definition Without a doubt, a consistent definition of the basic linguistic units is of utmost importance for the study of word length. Zero-syllable Words in Determining Word Length Irrespective of the theoretical problems of defining the word, there can be no doubt that the latter is one of the main formal textual and perceptive units in linguistics, which has to be determined in one way or another.
Knowing that there is no uniquely accepted, general definition, which we can accept as a standardized definition and use for our purposes, it seems reasonable to discuss relevant available definitions. As a result, we should then choose one intersubjectively acceptable definition, adequate for dealing with the concrete questions we are pursuing.
Taking into consideration syntactic qualities, and differentiating autosemantic vs. Subsequent to this discussion of three different theoretical definitions, we will try to work with one of these definitions, of which we demand that it is acceptable on an intersubjective level.
The decisive criterium in this next step will be a sufficient degree of formalization, allowing for an automatic text processing and analysis. Rather, what can be realized, is an attempt to show which consequences arise if one makes a decision in favor of one of the described options. Since this, too, cannot be done in detail for all of the above-mentioned alternatives, within the framework of this article, there remains only one reasonable way to go: We will tentatively make a decision for one of the options, and then, in a number of comparative studies, empirically test which consequences result from this decision as compared to the theoretical alternatives.
This will be briefly analyzed in the following work and only in the Slovenian language, but under special circumstances, and with specific modifications. In the previous discussion, we already pointed out the weaknesses of this defini- tion; therefore, we will now have to explain that we regard it to be reasonable to take just the graphematic-orthographic definition as a starting point.
It can therefore be expected that the results allow for some intersubjective comparability, at least to a particular degree. Zero-syllable Words in Determining Word Length b Second, since the definition of the units involves complex problems of quantifying linguistic data, this question can be solved only by way of the assumption that any quantification is some kind of a process which needs to be operationally defined. The word thus being defined according to purely formal criteria — i.
This, in turn, can serve as a guarantee that an analysis on all other levels of language i. The definition chosen above is, of course, of relevance for the automatic pro- cessing and quantitative analysis of text s. In detail, a number of concrete textual modifications result from the above-mentioned definition. In case of single elements, they are processed according to their syllabic structure. Particularly with regard to foreign language elements and passages, attention must be paid to syllabic and non-syllabic elements which, for the two languages under consideration, differ in func- tion: cf.
It should be noted here that irrespective of these secondary manipulations the original text structure remains fully recognizable to a researcher; in other words, the text remains open for further examinations e.
Altmann et al. Unuk 3. In order to automatically measure word length it is therefore not primarily necessary to define the syllable boundaries; rather, it is sufficient to determine all those units phonemes which are characterized by an increased sonority and thus have syllabic function.
On the other hand, empirical sonographic studies show that there are no bilabial fricatives in Slovenian standard language cf. Srebot-Rejec Of course, 2 For further discussions on this topic see: Tivadar , Srebot Rejec , Slovenski pravopis ; cf. On the Question of zero-syllabic Words The question whether there is a class of zero-syllabic words in its own right, is of utmost importance for any quantitative study on word length.
With regard to this question, two different approaches can be found in the research on the frequency of x-syllabic words. In this context, it will be important to see if consideration or neglect of this special word class results in statistical differences, and how much information consideration of them offers for quantitative studies.
As can be seen, we are concerned with two zero-syllable prepositions and with corresponding orthographical-graphematic variants for their phonetic realiza- tions. As opposed to this, these prepositions are treated as zero-syllable words in modern Slovenian; they thus exemplify the following general trend: original one-syllable words have been transformed into zero-syllable words.
Obviously, there are economic reasons for this reduction tendency. From a phonematic point of view, one might add the argument that these prepositions do not display any suprasegmental properties, i. Following this diachronic line of thinking might lead one to assume that zero-syllable words should or need not be considered as a specific class in linguo-statistic studies.
Incidently, the depicted trend i. Yet, as was said above, it is not our aim to provide a theo- retical solution to this open question. Nor do we have to make a decision, here, whether zero-syllable words should or should not be treated as a specific class, i.
Rather, we will leave this question open and shift our attention to the empirical part of our study, testing what importance such a decision might have for particular statistical models. Descriptive Statistics The statistical analyses are based on Slovenian texts, which are considered to represent the text corpus of the present study.
The whole number of texts is divided into the following groups4 : literary prose, poetry, journalism. The detailed reference for the prose and poetic texts are given in Tables 4. Table 4. Based on these considerations, and taking into account that the text data basis is heterogeneous both with regard to content and text types, statistical measures, such as mean, standard deviation, skewness, kurtosis, etc. Level I The whole corpus is analyzed under two conditions, once considering zero- syllable words to be a separate class in their own right, and once not doing so.
One can thus, for example, calculate relevant statistical measures or analyze the distribution of word length within one of the two corpora. Level II Corresponding groups of texts in each of the two corpora can be compared to each other: one can, for example, compare the poetic texts, taken as a group, in the corpus with zero-syllable words, with the corresponding text group in corpus without zero-syllable words.
Level III Individual texts are compared to each other. Here, one has to distinguish different possibilities: the two texts under consideration may be from one and the same text group, or from different text groups; additionally, they may be part of the corpus with zero-syllable words or the corpus without zero-syllable words.
Level IV An individual text is studied without comparison to any other text. A larger positive skewness implies a right skewed distribution. In the next step, we analyze which percentage of the whole text corpus is represented by x-syllable words.
Text no. Three Text Types Figure 4. It should be noted that many poetic texts do not contain any 0-syllable words at all. Of the 51 poetic texts, only 26 contain such words.
Analysis of Mean Word Length in Texts The statistical analysis is carried out twice, once considering the class of zero- syllable words as a separate category, and once considering them to be proclitics. Our aim is to answer the question, whether the influence of the zero-syllable words on the mean word length is significant. In the next step concentrating on the mean word length value of all texts Level I , two vector variables are introduced, each of them with components: W C 0 and W C.
The i-th component of the vector variable W C 0 defines the mean word length of the i-th text including zero-syllable words. In analogy to this, the i-th com- ponent of the vector variable W C gives the mean word length of the i-th text excluding zero-syllable words see Table 4. In order to obtain a more precise structure of the word length mean values, the analyses will be run both over all texts of the whole corpus Level I , and over the given number of texts belonging to one of the following three text types, only Level II : i literary prose L , ii poetry P , iii journalistic prose J.
A scatterplot is a graph which uses a coordinate plane to show the relation correlation between two variables X and Y.
Each point in the scatterplot represents one case of the data set. In such a graph, one can see if the data follow a particular trend: If both variables tend in the same direction that is, if one variable increases as the other increases, or if one variable decreases as the other decreases , the relation is positive. There is a negative relationship, if one variable increases, whereas the other decreases.
The more tightly data points are arranged around a negatively or positively sloped line, the stronger is the relation. If the data points appear to be a cloud, there is no relation between the two variables. In the following graphical representations of Figure 4. In our case, the scatterplot shows a clear positive, linear dependence between mean word length in the texts both with and without zero-syllable words , for each pair of variables.
This result is corroborated by a correlation analysis. W C 0 b Scatterplot W L vs. W P 0 d Scatterplot W J vs. W J 0 Figure 4.
As to our data, a strong dependence at the 0. Let us therefore take a look at the histograms of each of the eight new variables. The first pair of histograms cf. Figure 4. Still, we have to test these assumptions. Usually, either the Kolmogorov-Smirnov test or the Shapiro-Wilk test are ap- plied in order to test if the data follow the normal distribution. Since, in our case, the parameters of the distribution must be estimated from the sample data, we use the Shapiro-Wilk test, instead. This test is specifically designed to detect deviations from normality, without requiring that the mean or variance of the hypothesized normal distribution are specified in advance.
To determine whether the null hypothesis of normality has to be rejected, the prob- ability associated with the test statistic i. If this value is less than the chosen level of significance such as 0.
The obtained p-values support our assumptions, i. In the following analyses, we shall focus on the second analytical level, i. In order to test this, we can apply the t-test for paired samples.
This test compares the means of two variables; it computes the difference between the two vari- ables for each case, and tests if the average difference is significantly different from zero. This means that we test the following hypothesis: H0 : There is no significant difference between the theoretical means i.
Before applying the t-test, we have to test if the variables d L , dP , dJ are also normally distributed. As they are linear combinations of normally dis- tributed variables, there is sound reason to assume that this is the case.
The Shapiro-Wilk test yields the p-values given in Table 4. The histogram of the variable dP shows the same result cf. In spite of the result of the Shapiro- Wilk test, we therefore apply a one sample t-test assuming that d P is normally distributed.
Two distribution functions for variables which denote mean word length of texts with and without zero-syllable words have the same shape, but they are shifted, since their expected values differ. The following Figures 4. It should be noted that this conclusion can not be generalized. As long as the variables dL , dP , dJ are normally distributed, our statement is true. Yet, normality has to be tested in advance and we can not generally assume normally distributed variables.
In the next step we show the box plots and error bars of the variables d L , dP , dJ. A box plot is a graphical display which shows a measure of location the median-center of the data , a measure of dispersion the interquartile range, i. Horizontal lines are drawn both at the median — the 50th percentile q0. The horizontal lines are joined by vertical lines to produce the box. A vertical line is drawn up from the upper quartile to the most extreme data point i.
The most extreme data point thus is min x n , q0. Short horizontal lines are added in order to mark the ends of these vertical lines. The difference in the mean values of the three samples is obvious; also it can clearly be seen that all three samples produce symmetric distributions, variable dJ displaying the largest variability.
As can be seen, the confidence intervals do not overlap; we can therefore conclude that the percentage of zero-syllable words possibly may allow for a distinction between different text types. It turns out that the number of sylla- bles per word i. This class of words may either be considered to be a separate word-length class in its own right, or as clitics.
Without making an a priori decision as to this question, the mean word length of Slovenian texts is analyzed in the present study, under these two conditions, in order to test the statistical effect of the theoretical decision. In the present study, the material is analyzed from two perspectives, only: mean word length is calculated both in the whole text corpus Level I , and in three different groups of text types, representing Level II: literary, journalistic, poetic.
These empirical analyses are run under two conditions, either including the zero-syllable words as a separate word length class in its own right, or not doing so. Zero-syllable Words in Determining Word Length Based on these definitions and conditions, the major results of the present study may be summarized as follows: 1 As a first result, the proportion of zero-syllable words turned out to be relatively small i.
Furthermore, it can be shown that the mean word length in texts under both conditions are highly correlated with each other; the positive linear trend, which is statistically tested in the form of a correlation analysis and graphically represented in Figure 4. As a result, it turns out that mean word length is normally distributed in the three text groups analyzed Level II , but, interestingly enough, not in the whole corpus Level II. Based on this finding, further analyses concentrate on Level II, only.
Therefore, t-tests are run, in order to compare the mean lengths between the three groups of texts on the basis of the differences between the mean lengths under both conditions. As a result, the expected values of mean word length significantly differ between all three groups.
To summarize, we thus obtain a further hint at the well-organized structure of word length in texts. Altmann, G. Figge zum Stutt- gart. Bajec, A. Predlogi in predpone. Best, K. Genzor; S. Wimmer; G.
Altmann; R. Girzig, P. Grotjahn, R. Grzybek, P. Jachnow, H. Lehfeldt, W. Jachnow ed. Lekomceva, M. Tom 1. Rottmann, Otto A. Royston, P. Schaeder, B. Srebot-Rejec, T. Tivadar, H. Unuk, D. Doktorska disertacija. Figure 5. Many of the relevant psychological findings seem to be interesting for linguistics as well: the results reported e.
Of particular linguistic interest is the question whether the serial position effects shown in the recall of lists of unconnected words show in the recall of real sentences as well. Are the underlying processes also efficient in real sentence processing and in connected discourse? Having failed to disprove the charges, Taylor was later fired by the president\” p. The serial position curve reported by Fenk 25 shows a marked recency effect only in auditory presentation of the sentence.
But these results originate from only two different sentences presented simultaneously in two different sense modalities. Subjects were instructed to write down as much as they could remember from the last sentence before the test pause. Nevertheless the family of curves shows a rather weak primacy effect and a marked recency effect.
Data from this experiment were re-analyzed in order to investigate further questions. Wordclass-specific effects on the serial position curve?
In brief: The relevant division here is between context-specific content words and rather context-independent function words. Ad b : A widely accepted model concerning our memory says: After having ex- tracted the meaning of an actual clause, its verbatim form words and syntax is rapidly lost from memory, while the meaning is preserved and affects e.
This conception is strongly influ- enced by Sachs On the other hand, recall of previous sentences indicates that they had received a relatively thorough semantic interpretation. The first quarter I was defined as the primacy part of the sentence, II and III taken together as the medium part, and the last 25 percent of the words IV as the recency part. But the alternative — to define the primacy part and the recency part in terms of a fixed number of words — would again be arbitrary: How many words should be fixed?
Our operationalization, however, offers a wide range of applications and es- tablishes a firm proportion between, on the one hand, the primacy and recency part, and, on the other hand, the part in between and the sentence as a whole. And it has proved to bring about significant results. Thus, a quantification in absolute terms did not make much sense, and the recall scores had to be related to the number of words presented.
Table 5. Actually there is, as can be seen from the values in Table 5. But in both cases this convergence is far from significant. Three more or less hypothetical regularities The formulation of the first of the following assumptions is motivated by the occasional observation that our test sentences taken from a Glasersfeld text showed a tendency of an increase of content words and a decrease of function words during a sentence.
Results strongly indicate that this is a general tendency at least in German texts. And if our tentative explanation section 4 of this regularity holds, its scope should not be restricted to German texts. Regularities 3. Regularity 3. This statistical regular- ity has proven to be the most powerful one in the explanation of word order in frozen conjoined expressions Fenk-Oczlon , and it seems that its range of validity can be extended on clauses in general. In this present paper we will state this generalized rule mainly as an inferential step to our third regularity 3.
Despite the small sample of only ten sentences, the relevant differences proved to be significant in the Wilcoxon test Table 5. These differences in the distribution of the instances of the two word classes were, as already mentioned in section 2. A pilot study was conducted in order to find some indications of possible generalizations of this tendency.
The sample of authors was increased — nine more German text passages, four of them from scientific books, five from literary books. Taken to- gether with the already analysed text passages from Glasersfeld this is a sample of ten five scientific, five literary text passages, and a sample of ten sentences from each of these passages, i. Source texts are listed at the end of the paper. She was instructed not to collect ten successive sentences from each passage into the sample, but — where possible — each third sentence.
Sometimes she had to overleap more than two sentences, e.