The present invention is directed to a system and method for efficiently and cost effectively determining an accurate depth of interaction for a crystal that may be used for correcting parallax error and repositioning LORs for more clear and accurate imaging. The present invention is directed to a detector assembly having a thin sensor (e.g., APD) deployed in front of the detector (the side where the radioactive source is located and the photon is arriving to hit the detector) and a second sensor (APD or photomultiplier) on the opposite side of the detector. The light captured by the two interior and exterior sensors which is proportional to the energy of the incident photon and to the distance where the photon was absorbed by the detector with respect to the location of the two sensors, is converted into an electrical signal and interpolated for finding the distance from the two sensors which is proportional to the location where the photon hit the detector.

1. Field of the Invention
The present invention relates to radiation detectors. More particularly, the present invention relates to a system and method for correcting parallax error in a detector resulting from inaccurately assessing where the photon interacted with the detector, and thereby increasing efficiencies of traditional Positron Emission Tomography (PET) devices on a photons per unit of radiation basis.
2. Description of Related Art
These devices (detectors) are about 200 times smaller than the large detectors for high-energy physics and require identification of only one particle, the photon. The task to be solved of capturing and identifying the particles is relatively easier than before: one particle instead of five on a detector 200 times smaller.
The use of positron emissions for medical imaging has been well document from the early 1950's, see "A History of Positron Imagining," Brownell, Gordon, presented on Oct. 15, 1999, Massachusetts General Hospital, which is incorporated herein by reference in its entity. PET imaging has advantages over other types of imaging procedures. Generally, PET scanning provides a procedure for imaging the chemical functionality of bodily organs rather than imaging only their physical structure, as is commonly available with other types of imaging procedures such as X-ray, Computerized Tomography (CT), or Magnetic resonance imaging (MRI). PET scanned images allow a physician to examine the functionality heart, brain, and other organs as well as diagnosing disease groups which cause changes in the cells of a body organ or in the manner they grow, change, and/or multiply out of control, such as cancers.
Positron Emission Tomography (PET) is a medical imaging technique that involves injecting a natural compound, such as sugar or water, labeled with a radioactive isotope into a patient's body to reveal internal biological processes. As the isotope (positron) circulates within the patient's body. The positron annihilates with and electron and emits pairs of photons in diametrically opposed directions (back-to-back). A PET device is made of a set of detectors coupled to thousands of sensors that surround the human body. These detectors (crystals) capture the photons emitted by the isotope from within the patient's body at a total rate of up to hundreds of millions per second, while the sensors (transducers such as PMTs) convert them to electrical signals, and send the signals to the electronics.
Other applications for detecting particles (photons, electrons, hadron, muon and jets) are well known, such as with regard to experiments in high energy physics. While particle detection in high energy physics and medical imaging have some common ground, differences between the disciplines exist. One distinction between the usages is that the detectors used in medical imaging are approximately 200 times smaller than the larger detectors employed in high-energy physics applications. Moreover medical imaging PET applications require the identification of only a single type of particle, the photon.
Typically, prior art Positron Emission Tomography (PET) devices require the injection into the patient's body of a radiation dose that is 10 to 20 times the maximum radiation dose recommended by the International Commission on Radiological Protection (ICRP). This amount is necessary because, at best, prior art PET devices only detect 2 photons out of 10,000 emitted in the patients' body. Currently the largest manufacturers of PET (General Electric Company and Siemens AG (ADR)) which command in excess of 90% of the world market, are manufacturing two different PET (PET/CT) systems with very similar performance and are selling them at very similar prices. However, although the price and performance of the systems from the different manufactures are comparable, one manufacturer's system (Siemens) uses nearly ideal crystal detectors, while contrastingly, the other manufacturer's system (General Electric) uses cheaper, lower quality crystal detectors with slower decay time. Consequently, the manufacturer using the cheaper, lower cost detectors, expend on the order of only 10% the price of the ideal crystals used in their competitor's systems. Thus, the question arises: how it could be that even though one manufacturer uses crystals detectors that are ten times more expensive that the other manufacturer, the price and performance of the two PET systems from the different manufacturers are very comparable.
Anecdotally, the present inventor has analyzed the progress of the most significant PET improvements made in the most recent 17 years, see "400+ times improved PET efficiency for lower-dose radiation, lower-cost cancer screening," 3D-Computing, Jun. 30, 20010, ISBN: 0970289707, which is incorporated herein by reference in its entity. During that time period the efficiency of PET improved at a rate of between two and three times every five years. The analysis included technical literature, patents (including those assigned to GE and Siemens) and also PETs that were built as prototypes at several universities but were never commercialized. At the current improvement rate of PET advancement, conservatively it would take several decades of improvements for the radiation dose necessary for a PET procedure to come within the maximum radiation dose recommended by the ICRP.
What is needed is a means for increasing the accuracy and efficiencies of PET devices, enabling caregivers to more accurately diagnose ailments related to the functionality of body organs and not just inferences from the structure of the organs. Additionally, what is needed is a quantum advance forward in PET devices and procedures wherein patients can receive the benefits of PET imaging without the associative risks from the radioactive doses necessary for the procedures. Finally, what is needed is a means for reducing the associated risks and increasing detection efficiencies associated with PET imaging procedures to such an extent that the benefits of PET imaging can be applied in well body care and preventative medicine strategies for apparently healthy individuals; as a standard health assessment and diagnostic tool for regular, periodic checkups.

Method and apparatus for determining depth of interactions in a detector for three-dimensional complete body screening


An electronic circuit includes a primary wide bandgap bipolar power switching device configured to supply a load current in response to a control signal applied to a control terminal thereof, and a driver device configured to generate the control signal. At least one of the primary switching device or the driver device may include an optically triggered switching device. A discrete wide bandgap semiconductor device includes a primary bipolar device stage configured to switch between a conducting state and a nonconducting state upon application of a control current, and a bipolar driver stage configured to generate the control current and to supply the control current to the primary bipolar device stage. At least one of the primary bipolar device stage and the bipolar driver stage may include an optically triggered wide bandgap switching device.

Silicon carbide thyristors are described, for example, in U.S. Pat. No. 5,539,217 (the '217 patent) the disclosure of which is incorporated herein by reference as if set forth fully. The thyristors described in the '217 patent are three terminal devices having a gate and one of an anode or a cathode on a first side of the device and the other of the anode and the cathode on the opposite side of the device. Such silicon carbide thyristors may exhibit improved power handling capabilities over similar silicon thyristors.
Light-activated thyristors having an integrated light source and a silicon carbide active layer have been described in U.S. Pat. No. 5,663,580. Such devices may include four terminal devices including anode and cathode terminals for a light emitting diode which acts to trigger a thyristor having its own anode and cathode terminals.
Light activated silicon thyristors have been utilized in high power applications. For example, optically triggered parallel lateral thyristors are described in U.S. Pat. No. 4,779,126.
While silicon carbide thyristors may provide improved power handling capabilities over comparably sized silicon devices, it may be difficult to form large scale thyristors in silicon carbide. For example, in silicon, a single thyristor may be made on a wafer such that the thyristor is substantially the same size as the wafer. However, manufacturing defect-free silicon carbide wafers may be difficult. Thus, a device which consumes an entire silicon carbide wafer may have defects incorporated into the device which may limit its performance.
Moreover, the large size of silicon thyristors makes the design of an optical driver for such devices a challenge, since it is desirable to apply a uniform light to a large surface area of the device.

Optically triggered wide bandgap bipolar power switching devices and circuits


In order to allow a bag to be easily unsealed by sliding both sides of the bag in a longitudinal direction of a zipper tape irrespective of the rigidity of the zipper tape, a zipper-tape bag according to an aspect of the invention includes: a bag body including at least a pair of facing surfaces; and an elongated zipper tape whose cross sectional profile includes first and second bases each bonded to corresponding one of facing surfaces, and mutually engageable first and second engagement portion respectively protruded from the first and second bases, the zipper tape including an intermediate hinge at at least one point in the longitudinal direction.

Zipper-tape bags have been widely used for packaging various goods such as medicines and foods. One of the advantages of the zipper-tape bags is that the zipper-tape bags are easily unsealable and resealable. The bag can be unsealed by a user's operation of pulling both sides of the bag, onto which the zipper tape is bonded, in a direction away from each other to disengage the zipper tape. In contrast, the user can engage the zipper tape to reseal the bag by pressing the both sides of the bag so that the sides move toward each other.
The both sides of the bag are typically pinched by fingers and pulled in a direction perpendicular to a longitudinal direction of the zipper tape in unsealing the zipper-tape bag. In this case, both hands of a user are required for the unsealing. In contrast, Patent Literature 1 discloses a bag capable of being unsealed by a user's operation of mutually oppositely sliding both sides of the bag along a longitudinal direction of the zipper tape. In this case, the user can disengage the zipper tape to unseal the bag by pinching and twisting the both sides of the bag by fingers (specifically, a thumb and an index finger) of one hand.

Bag with attached zipper tape, manufacturing method of bag with attached zipper tape


The target according to the present disclosure is configured to indicate to the shooter whether the shot hit or missed the target. The target also provides the shooter feedback as to shot placement relative to particular locations on the target. This configuration is advantageous for many types of shooting and is especially advantageous in situations where immediate and consistent shot placement feedback is desire.

Shooting targets are most commonly paper images that include a bullseye in the center of concentric rings. Paper based targets are generally not configured to move or make noise when impacted by the bullet. To determine the point of impact on the target, the shooter typically either walks up to the target to examine the target or the shooter examines the target from a distance with the aid of a spotting scope. The feedback regarding shot placement on such targets is therefore not immediate.
Reactive shooting targets provide the shooter immediate visual and/or audio indication of whether the shot hit or missed the target. An example reactive target is a hanging steel plate. When the bullet impacts the steel plate, the plate will swing and the impact can also be heard. These reactive targets provide advantages over passive targets as the shooter can immediately know if the target was hit. The present disclosure provides an improved reactive type shooting target.

Reactive target with point of impact feedback


A system and method are disclosed for training a system or a model to allow estimation of the value of livestock that is farmed for monetary gain. The various aspects of the invention include generation of data that is used to supplement or augment capture or real data, wherein the subject of the data is an animal. Labels or attributes are generated and validated.

Artificial Intelligent System (AIS) are trained system that perform a specific task. For example, an AIS can be used to recognize a subject when the AIS is trained to recognize the subject using training data. Currently, known methods of training AIS include using captured data that is labeled or tagged. However, using data to train an AIS or any similar system can take a long time, especially when it comes to animals. Furthermore, there currently is no efficient method for controlling or generating the training data needed to train an AIS for recognition of animals that are farmed for financial gain. Therefore, what is needed is a system and method that allows generation of training data that can be used to train a system in a short period of time and with a high degree of control over variations in the training data.

System and method to analyse an animal's image for market value determination


A drape according to the present invention is constructed of or includes conductive and insulating drape segments and is disposed over a top surface of a thermal treatment system having a basin recessed therein. A portion of the drape is pushed down into, and conforms to, the basin to form a drape container or receptacle within the basin for collecting a sterile medium. The conductive segments provide a signal indicating the presence of liquid and/or leaks within the drape container to the system to facilitate control of system operation. In addition, a drape utilized for a plural basin thermal treatment system may form a drape receptacle within each basin. Each drape receptacle includes conductive and insulating drape segments to detect the presence of liquid and/or a leak within that drape receptacle. The conductive segments of the drape receptacles provide signals to the system to facilitate control of system operation.

1. Technical Field
The present invention pertains to surgical drapes. In particular, the present invention pertains to a surgical drape to contain a sterile surgical solution and facilitate detection of the presence of solution and/or leaks within a thermal treatment system basin. The surgical drape is preferably utilized with thermal treatment systems that thermally treat a sterile surgical liquid, such as the types disclosed in U.S. Pat. No. 4,393,659 (Keyes et al.), U.S. Pat. No. 4,934,152 (Templeton), U.S. Pat. No. 5,163,299 (Faries, Jr. et al.), U.S. Pat. No. 5,331,820 (Faries, Jr. et al.), U.S. Pat. No. 5,333,326 (Faries, Jr. et al.), U.S. Pat. No. 5,400,616 (Faries, Jr. et al.), U.S. Pat. No. 5,402,644 (Faries, Jr. et al.), U.S. Pat. No. 5,429,801 (Faries Jr. et al.), U.S. Pat. No. 5,457,962 (Faries, Jr. et al.), U.S. Pat. No. 5,502,980 (Faries, Jr. et al.), U.S. Pat. No. 5,522,095 (Faries, Jr. et al.), U.S. Pat. No. 5,524,643 (Faries, Jr. et al.), U.S. Pat. No. 5,551,240 (Faries, Jr. et al.), U.S. Pat. No. 5,615,423 (Faries, Jr. et al.), U.S. Pat. No. 5,653,938 (Faries, Jr. et al.), U.S. Pat. No. 5,809,788 (Faries, Jr. et al.), U.S. Pat. No. 5,816,252 (Faries, Jr. et al.), U.S. Pat. No. 5,857,467 (Faries, Jr. et al.), U.S. Pat. No. 5,862,672 (Faries, Jr. et al.), U.S. Pat. No. 5,879,621 (Faries, Jr. et al.), U.S. Pat. No. 5,950,438 (Faries, Jr. et al.), U.S. Pat. No. 6,003,328 (Faries, Jr. et al.), U.S. Pat. No. 6,035,855 (Faries, Jr. et al.), U.S. Pat. No. 6,087,636 (Faries, Jr. et al.), U.S. Pat. No. 6,091,058 (Faries, Jr. et al.), U.S. Pat. No. 6,255,627 (Faries, Jr. et al.) and U.S. Pat. No. 6,371,121 (Faries, Jr. et al.) and U.S. patent application Publication No. 2003/0231990 (Faries, Jr. et al.). The disclosures in the above-mentioned patents and patent application publication are incorporated herein by reference in their entireties.
2. Discussion of the Related Art
The above-referenced Keyes et al. U.S. Pat. No. 4,393,659 discloses a surgical slush producing system having a cabinet with a heat transfer basin at its top surface. A refrigeration mechanism in the cabinet takes the form of a closed refrigeration loop including: an evaporator in heat exchange relation to the outside surface of the heat transfer basin; a compressor; a condenser; and a refrigeration expansion control, all located within the cabinet. A separate product basin is configured to be removably received in the heat transfer basin. Spacers, in the form of short cylindrical stubs or buttons, are arranged in three groups spaced about the heat transfer basin and projecting into the heat transfer basin interior to maintain a prescribed space between the two basins. During use, that space contains a thermal transfer liquid, such as alcohol or glycol, serving as a thermal transfer medium between the two basins. A sterile drape, impervious to the thermal transfer medium, is disposed between the product basin exterior and the liquid thermal transfer medium to preserve the sterile nature of the product basin. Surgically sterile liquid, such as sodium chloride solution, is placed in the product basin and congeals on the side of that basin when the refrigeration unit is activated. A scraping tool is utilized to remove congealed sterile material from the product basin side to thereby form a slush of desired consistency within the product basin. Some users of the system employ the scraping tool to chip the solid pieces from the basin side.
As noted in the above-referenced Templeton U.S. Pat. No. 4,934,152, the Keyes et al. system has a number of disadvantages. In particular, the separate product basin must be removed and re-sterilized after each use. Additionally, the glycol or other thermal transfer medium is highly flammable or toxic and, in any event, complicates the procedure. The Templeton U.S. Pat. No. 4,934,152 discloses a solution to these problems by constructing an entirely new apparatus whereby the product basin is eliminated in favor of a sterile drape impervious to the sterile surgical liquid, the drape being made to conform to the basin and directly receive the sterile liquid. Congealed liquid is scraped or chipped from the sides of the conformed drape receptacle to form the desired surgical slush.
The Faries, Jr. et al. U.S. Pat. No. 5,163,299 notes that scraping congealed liquid from the drape is undesirable in view of the potential for damage to the drape, resulting in a compromise of sterile conditions. As a solution to the problem, the Faries, Jr. et al. U.S. Pat. No. 5,163,299 proposes that the drape be lifted or otherwise manipulated by hand to break up the congealed liquid adhering to the drape. Although this hand manipulation is somewhat effective, it is not optimal, and often is inconvenient and constitutes an additional chore for operating room personnel. Accordingly, several of the Faries, Jr. et al. (e.g., U.S. Pat. Nos. 5,331,820; 5,400,616; 5,457,962; 5,502,980; 5,653,938; 5,809,788; 5,857,467; 5,950,438; 6,003,328; and 6,035,855) resolve the problem of manual drape manipulation by disclosing various techniques and/or dislodgment mechanisms to automatically remove the congealed liquid adhering to the drape without endangering the integrity of the drape.
The Templeton U.S. Pat. No. 4,934,152 further discloses an electrical heater disposed at the bottom of the basin to convert the sterile slush to warmed liquid, or to heat additional sterile liquid added to the basin. Templeton describes the need for such warm sterile liquid as occurring after a surgical procedure is completed to facilitate raising the body cavity of the surgery patient back to its normal temperature by contact with the warmed liquid. However, there are a number of instances during a surgical procedure when it is desirable to have simultaneous access to both warmed sterile liquid and sterile surgical slush. Accordingly, several of the Faries, Jr. et al. (e.g., U.S. Pat. Nos. 5,333,326; 5,429,801; 5,522,095; 5,524,643; 5,615,423; 5,653,938; 5,816,252; 5,862,672; 5,857,467; 5,879,621; 6,091,058; and 6,255,627) disclose a manner in which to simultaneously provide both surgical slush and warmed surgical liquid during a surgical procedure by utilizing a machine having plural basins with each basin either producing surgical slush or heating a sterile liquid. This machine typically utilizes a single surgical drape that forms a drape receptacle within each basin to collect sterile slush and heated sterile liquid produced by the machine in the respective basins.
In addition, several of the drapes and thermal treatment systems disclosed in the above-mentioned patents include specialized features to enhance various aspects of thermal treatment system operation. For example, some of the specialized features may include: bladder drapes (e.g., as disclosed in U.S. Pat. Nos. 5,809,788; 5,950,438; and 6,003,328); drapes having plates or disks (e.g., as disclosed in U.S. Pat. Nos. 5,457,962 and 5,502,980); reinforced drapes (e.g., as disclosed in U.S. Pat. No. 5,857,467); drape indicators and corresponding thermal treatment system detection devices to ensure sterility by enabling system operation in response to detecting a sterile drape placed on the system (e.g., as disclosed in U.S. Pat. Nos. 5,653,938 and 5,879,621); drapes having indicia to direct placement of the drapes on thermal treatment systems (e.g., as disclosed in U.S. Pat. No. 5,615,423); surgical drapes constructed of materials having a coefficient of friction in a particular range and/or drapes including attachment mechanisms such that a drape may withstand being drawn under a dislodgment mechanism (e.g., as disclosed in U.S. Pat. No. 6,035,855); a stand to elevate objects within a heated basin above the basin floor (e.g., as disclosed in U.S. Pat. No. 6,087,636) and/or a heater configured to cover a portion of the basin (e.g., as disclosed in U.S. Pat. Nos. 6,091,058 and 6,255,627) to prevent the drape from overheating and puncturing when objects are placed within the basin; and remote control of a thermal treatment system (e.g., as disclosed in U.S. Pat. No. 6,371,121).
However, when insignificant amounts of liquid are present within a thermal treatment system basin, the system heating and cooling mechanisms operate with minimal thermal resistance, thereby enabling the mechanisms to become damaged. Further, the drapes employed by the system may be damaged by being disposed proximate the heating or cooling mechanism without having the liquid to absorb the thermal energy. Since only sterile drapes are to be used during surgical procedures, a leak in a surgical drape compromises sterility and contaminates the entire surgical procedure, thereby increasing the risk of injury to a patient.
The related art has attempted to overcome this problem by employing sensing devices with surgical drapes. For example, U.S. Pat. No. 5,524,643 (Faries, Jr. et al.) discloses a surgical drape combined with a sensor, preferably attached to the drape, to detect the presence of liquid within a drape container conforming to a heating/cooling thermal treatment system basin. An alternative embodiment employs sensors at opposite surfaces of the drape to measure conductance and, thereby, leakage through the drape. A microprocessor of each embodiment receives a signal representing, for example, an electrical conductance measurement and determines the presence of liquid and/or a leak. If liquid is not present or a leak is determined to exist, the microprocessor disables a temperature controller for the basin to prevent damage to the drape and heating and cooling mechanisms.
U.S. Pat. No. 5,816,252 (Faries, Jr. et al.) discloses a drape for use with a system for thermally treating a sterile medium. The drape includes liquid sensitive material that changes color upon contact with liquid to indicate the presence of a leak. The liquid sensitive material may be placed between the drape and a receiving basin or affixed to the drape in the form of indicia symbolically directing placement of the drape over the system. The system may include a single basin and be of the type that either thermally cools or heats the sterile medium, or the system may include a plurality of basins with each basin either thermally cooling or heating the sterile medium. The liquid sensitive material detects leaks within the drape while assisting the operator in properly aligning and placing the drape over the system.
U.S. Pat. No. 6,102,044 (Naidyhorski) discloses an electrode carrying surgical drape including a polymeric film having opposing surfaces and an electrode receiving aperture therethrough. An electrode is disposed through the aperture, while patches sealingly affix electrode portions to each of the opposing surfaces of the polymeric film in the vicinity of the aperture to form a reinforced laminated structure capable of maintaining the sterility of an established sterile field.
The above-described systems can stand some improvement. In particular, the Faries, Jr. et al. sensor drape (U.S. Pat. No. 5,524,643) employs a plug connector disposed through the drape to facilitate connections between the drape sensor and the thermal treatment system, thereby complicating the process of effectively sealing the drape to prevent contamination of the sterile field. Further, the drape is required to be placed on the system with the plug aligned with a corresponding plug receptacle for system operation, thereby restricting the manners in which the drape may be positioned on the system to form the drape container. The Faries, Jr. et al. system employing liquid sensitive material with a drape (U.S. Pat. No. 5,816,252) indicates the presence of a leak within the drape container. However, this system relies on operating room personnel to respond to the leak indication and perform appropriate actions with respect to system operation. Thus, the system may continually operate in the presence of a drape container leak until personnel notice and respond to the leak indication, thereby increasing the risk of contamination of a surgical procedure and damage to the system heating or cooling mechanism when a drape leak occurs. Since the Naidyhorski drape includes an electrode disposed therethrough, the drape utilizes additional materials (i.e., a plurality of patches) to seal the electrode through the drape, thereby increasing system materials, complexity and costs.

This patent is subject to a terminal disclaimer.

Surgical drape and method of detecting fluid and leaks in thermal treatment system basins


A computer system includes physical memory devices of different types that store randomly-accessible data in a main memory of the computer system. In one approach, an operating system allocates memory from a namespace for use by an application. The namespace is a logical reference to physical memory devices in which physical addresses are defined. The namespace is bound to a memory type. In response to binding the namespace to the memory type, the operating system adjusts a page table to map a logical memory address in the namespace to a memory device of the memory type.

Various types of memory devices can be used to store data in the main memory of a computer system. One type of volatile memory device is a dynamic random access memory (DRAM) device. Various types of non-volatile memory device can include a NAND flash memory device or a non-volatile random access memory (NVRAM) device.
In an operating system, memory management is responsible for managing the main memory of the computer system. The memory management tracks the status of memory locations in the main memory (e.g., a memory status of either allocated or free). Memory management further determines the allocation of memory among various processes running on the operating system. When memory is allocated to a process, the operating system determines the memory locations that will be assigned to the process.
In one approach, an operating system uses paged allocation to divide the main memory into fixed-sized units called page frames. A virtual address space of a software program is divided into pages having the same size. A hardware memory management unit maps pages to frames in physical memory. In a paged memory management approach, each process typically runs in its own address space.
In some cases, the memory management unit (MMU) is called a paged memory management unit (PMMU). The MMU manages all memory references used by the operating system and performs the translation of virtual memory addresses to physical addresses. The MMU typically divides a virtual address space, which is the range of addresses used by the processor, into pages.
In some approaches, the MMU uses a page table containing page table entries to map virtual page numbers to physical page numbers in the main memory. In some cases, a cache of page table entries called a translation lookaside buffer (TLB) is used to avoid the need to access a page table stored in the main memory when a virtual address is mapped. When using virtual memory, a contiguous range of virtual addresses can be mapped to several non-contiguous blocks of physical memory.
In some cases, a page table entry can include information about page usage. Various examples include information regarding whether data has been written to the page, when the page was last used, the types of processes (e.g., user mode or supervisor mode) that may read and write the page, and whether the page should be cached.
In one approach, the TLB is implemented as content-addressable memory (CAM). The search key is the virtual address, and the search result is a physical address. If the requested address is in the TLB, the physical address retrieved from the search is used to access a physical memory device. If the requested address is not in the TLB, the page table is accessed in main memory.
In some cases, a virtual memory management system uses process identifiers to associate each page to a process. The association of process identifiers with virtual pages can be helpful for selecting pages to page out. For example, if the main code page of a process has been paged out, there is a reduced likelihood of immediate need for other pages belonging to that process.
More generally, a computer system can have one or more memory sub-systems. A memory sub-system can be a memory module, such as a dual in-line memory module (DIMM), a small outline DIMM (SO-DIMM), or a non-volatile dual in-line memory module (NVDIMM). A memory sub-system can include one or more memory components that store data. The memory components can be, for example, non-volatile memory components and volatile memory components. Examples of memory components include memory integrated circuits. Some memory integrated circuits are volatile and require power to maintain stored data. Some memory integrated circuits are non-volatile and can retain stored data even when not powered. Examples of non-volatile memory include flash memory, Read-Only Memory (ROM), Programmable Read-Only Memory (PROM), Erasable Programmable Read-Only Memory (EPROM) and Electronically Erasable Programmable Read-Only Memory (EEPROM) memory, etc. Examples of volatile memory include Dynamic Random-Access Memory (DRAM) and Static Random-Access Memory (SRAM). In general, a computer system can utilize a memory sub-system to store data at the memory components and to retrieve data from the memory components.
For example, a computer system can include one or more memory sub-systems attached to the computer system. The computer system can have a central processing unit (CPU) in communication with the one or more memory sub-systems to store and/or retrieve data and instructions. Instructions for a computer can include operating systems, device drivers, and application programs. An operating system manages resources in the computer and provides common services for application programs, such as memory allocation and time sharing of the resources. A device driver operates or controls a particular type of device in the computer; and the operating system uses the device driver to offer resources and/or services provided by the type of device. A central processing unit (CPU) of a computer system can run an operating system and device drivers to provide the services and/or resources to application programs. The central processing unit (CPU) can run an application program that uses the services and/or resources. For example, an application program implementing a type of application can instruct the central processing unit (CPU) to store data in the memory components of a memory sub-system and retrieve data from the memory components.
An operating system of a computer system can allow an application program to use virtual addresses of memory to store data in, or retrieve data from, memory components of one or more memory sub-systems of the computer system. The operating system maps the virtual addresses to physical addresses of one or more memory sub-systems connected to the central processing unit (CPU) of the computer system. The operating system translates the memory accesses specified at virtual addresses to the physical addresses of the memory sub-systems.
A virtual address space can be divided into pages. A page of virtual memory can be mapped to a page of physical memory in the memory sub-systems. The operating system can use a paging technique to access a page of memory in a storage device via a page of memory in a memory module. At different time instances, the same virtual page of memory in a memory module can be used as proxy to access different physical pages of memory in the storage device or another storage device in the computer system.
A computer system can include a hypervisor (or virtual machine monitor) to create or provision virtual machines. A virtual machine is a computing device that is virtually implemented using the resources and services available in the computer system. The hypervisor presents the virtual machine to an operating system as if the components of virtual machine were dedicated physical components. A guest operating system runs in the virtual machine to manage resources and services available in the virtual machine, in a way similar to the host operating system running in the computer system. The hypervisor allows multiple virtual machines to share the resources of the computer system and allows the virtual machines to operate on the computer substantially independently from each other.

Memory system for binding data to a memory namespace


A blood-pressure monitoring apparatus including a measuring device which includes an inflatable cuff adapted to apply a pressing pressure to a first body portion of a living subject and which measures a blood-pressure value of the living subject by changing the pressing pressure of the inflatable cuff, a blood-pressure-relating-information obtaining device which iteratively obtains a piece of blood-pressure-relating information which changes in relation to a change of the blood pressure of the living subject, a starting device for starting, when the obtained blood-pressure-relating information satisfies a predetermined condition with respect to at least one reference value, a blood-pressure measurement of the measuring device, and a display device which displays a first graphical representation of the obtained blood-pressure-relating information, and a second graphical representation of the reference value, so that the first graphical representation can be compared with the second graphical representation by the living subject such as a patient or a different person such as a doctor or nurse.

1. Field of the Invention
The present invention relates to a blood-pressure monitoring apparatus which monitors a blood pressure of a living subject based on information which changes in relation to the change of blood pressure of the subject.
2. Related Art Statement
As information relating to a pulse wave which propagates through an arterial vessel of a living subject, there are known a pulse-wave-propagation time DT and a pulse-wave-propagation velocity V.sub.M (m/s). The pulse-wave-propagation time DT is a time which is needed by the pulse wave to propagate between two different positions of the arterial vessel. Additionally, it is known that the above pulse-wave-propagation-relating information is, within a predetermined range, substantially proportional to the blood pressure ("BP", mmHg) of the living subject. Hence, there has been proposed a BP monitoring apparatus which determines, in advance, coefficients .alpha., .beta. in the following expression: EBP=.alpha.(DT)+.beta. (where a is a negative constant and .beta. is a positive constant), or EBP=.alpha.(V.sub.M)+.beta. (where .alpha. and .beta. are positive constants), based on two measured BP values of the subject and two measured pulse-wave-propagation time values (DT) or two measured pulse-wave-propagation velocity values (V.sub.M), iteratively determines an estimated BP value EBP of the subject, based on each piece of subsequently obtained pulse-wave-propagation-relating information, according to the above-indicated first or second expression, and starts a BP measurement using an inflatable cuff when an estimated BP value EBP has changed by not less than a predetermined amount or proportion from a prior value EBP determined at the time of the last BP measuring operation.
A relationship between pulse-wave-propagation-relating information and estimated BP value BP, represented by the above-indicated first or second expression, changes depending upon the condition of a central organ of the living subject (e.g., the condition of cardiac muscle) and/or the condition of a peripheral organ of the subject (e.g., the hardness of peripheral blood vessels, or the resistance of those vessels to the blood flow). Thus, there has been proposed a BP monitoring apparatus which obtains hertbeat-relating information (e.g., heart rate or pulse period) as central-organ-relating information, and peripheral-pulse-wave-area-relating information as peripheral-organ-relating information and which starts a BP measurement using an inflatable cuff when the pulse-wave-propagation-relating information (or the estimated BP value EBP calculated based on the pulse-wave-propagation-relating information) has changed by not less than a predetermined amount or proportion from the time of the last BP measuring operation and simultaneously when at least one of the hertbeat-relating information and the peripheral-pulse-wave-area-relating information has changed by not less than a predetermined amount or proportion from the time of the last BP measuring operation. An example of this BP monitoring apparatus is disclosed in U.S. Pat. No. 5,752,920.
However, the prior BP monitoring apparatuses as described above display only a digital value indicative of each piece of BP-relating information which is used in judging whether or not to start a BP measurement using the cuff, or a trend graph representing a timewise change of a plurality of pieces of BP-relating information. From only those items, however, the subject or a medical person who attends to the subject cannot judge whether the BP of the subject is near to, or is changing toward, a state in which a BP measurement using the cuff is started. Accordingly, the medical person can not give any treatments to the subject before a BP measurement using the cuff is actually started.


An agricultural machine is disclosed. The agricultural machine includes a frame including a first axle on a first side of the frame and a second axle on a second side of the frame; and a bogie axle pivotably mounted on each of the first and second axles of the frame. Each bogie axle includes a body with a front axle disposed at a front end of the body and a rear axle disposed at a rear end of the body. A front tire is mounted on the front axle of each bogie axle and a rear tire is mounted on the rear axle of each bogie axle. The front tire is a different size than the rear tire.

1. Field of the Invention
This invention relates to a bogie axle for a machine, in particular an agricultural machine.
2. Description of the Related Art
Agricultural machines are used to perform various agricultural functions. Typically, the agricultural machine operates on a field. These agricultural machines may include hay rakes, shredders, spreaders, plows, and wrappers.
One example of an agricultural machine is a hay rake apparatus 200 shown in FIG. 8. The hay rake 200 includes a wheeled cart 212, which includes a frame 214 and a tongue hitch 216 for attachment to a tractor or towing means (not shown), and a rake arm assembly 218. The wheeled cart 212 further includes one axle on each side thereof. A single tire 220 is mounted on each axle via a plurality of holes 221. The single tire 220 may be mounted on each axle via a hub provided on the axle.
The environment in which the agricultural machine operates over includes obstacles, such as holes, ruts, mounds, and foreign objects. These obstacles may not be visible to the operator of the agricultural machine. In addition, it may be difficult to avoid these obstacles during operation of the vehicle. Thus, the agricultural machine must deal with operating in an environment with such obstacles. During travel, the agricultural machine has to travel over and/or through the obstacles.
These obstacles are especially problematic for an agricultural machine with a single axle tire, as shown in FIG. 8. The agricultural machine with a single axle tire may not be able to roll over and/or through the obstacles. Even if the agricultural machine with a single axle tire is able to pass over or through the obstacle, this may cause damage to the agricultural machine. Difficulty in traveling over and through the obstacles may also reduce the efficiency of the function of the agricultural machine.


The present invention relates to a method and a device for small scale reactions, such as sample preparation of a desired substance in a sample. In the method using the device samples mixed with functionalized magnetic particles are magnetically transferred between different working stations on the device. The method uses a hydrophobic surface, such as a Petri dish, provided with hydrophilic spots of, for example, agarose beads located on said hydrophobic surface and provided with buffers, reactants or ligands.

There are many sample preparation methods used today. For example, electrophoresis is a widely used method for sample preparation of proteins and peptides. The sample may be separated in 1 dimensional or 2 dimensional electrophoresis, wherein 1D electrophoresis separates molecules on the basis of e.g. pI-value and 2D electrophoresis includes an additional separation according to size and possibly charge. For sample preparation, electrophoresis is cumbersome and time consuming. Another drawback is that the sample has to be eluted from the gel if it is desired to use or analyse the sample further.
Another example of sample preparation is liquid chromatography which may be used as 1D, 2D or MDLC (multi dimensional liquid chromatography) separation. The liquid chromatography may be sieving chromatography, ion exchange chromatography, hydrophobic interaction chromatography, affinity chromatography etc. The drawback with liquid chromatography is that it is less suited for handling very small amounts of sample. The limitation in handling small amounts of sample with chromatographic methods is in part overcome by using so called micro spin columns.
Other techniques that are currently in use for sample preparation of very small sample amounts make use of pre-coated microtiter plates. These plates can be prepared with ligands that can remove bulk impurities as well as be used for specific isolation of target components.
Yet another sample preparation approach is based on the use of magnetic beads. Magnetic beads are also available with ligands suited for removal of bulk proteins or isolation of specific target components. These materials are commonly handled in test tubes in combination with a manual pipetting procedure.
Various types of microfluidic systems have also been described for sample preparation and other manipulations (see e.g. P E Andersson: PharmaGenomics (2), 38-44 (2003)). A drawback in many of these is that the macro/micro interface becomes inconvenient, i.e. the transfer of a macroscopic (microliter/milliliter) sample into channels of nano/picoliter dimensions is a weak spot in the system. Further, they are often not well suited for handling small amounts of particulate materials.

Method and device for small scale reactions


Disclosed is a method and device adapter for managing devices in a data processing system that includes a plurality of device adapters connected for independent communication with at least one shared device (e.g. disk data storage device). The method comprises the steps of: issuing a command from a first of the plurality of adapters to the at least one shared device; setting, in the first adapter, first and second timeouts associated with the command; on expiration of the first timeout value, issuing a message from said first adapter to other(s) of the plurality of adapters to request the other adapter(s) to notify the first adapter of any work requested of the shared device by the other adapter(s); and on expiration of the second timeout value, initiating a recovery operation in the data processing system.

The present invention relates generally to the management of shared devices in a data processing system.
In data processing systems, device adapters are used to control attached devices for use by a host computer. Such device adapters may be incorporated into the host computer (internal) or embodied as external device adapters. An example of a device adapter incorporated into a host computer is a device adapter board that may have associated device driver software. An example of a device adapter embodied as an external device adapter is an external device controller unit that is connected by a communication link to the host computer.
Device adapters are typically used to control storage and other peripheral devices, to interpret requests from the computer into a form suitable for use by the devices, and to interpret responses from the devices into a form suitable for use by the computer. Typically, devices such as disk are connected to a single adapter and are used by a single host computer. More recently, multi-adapter environments have been developed in which devices are connected to multiple adapters that, in the case of internal adapters, may exist in one or more host computers. In one known arrangement, one of the device adapters is nominated as a master adapter and all I/O operations to the devices are coordinated by the master adapter. This arrangement has the disadvantage of high workload at the master adapter. An alternative arrangement may therefore be used in ,which the multiple adapters are able to independently initiate I/O operations to the shared devices. For some types of I/O operations, for example, RAID 5 writes, this second arrangement requires the use of a locking technique to prevent corruption of data on the shared device.
In a multi-adapter environment where each adapter can independently initiate I/O operations to the shared devices, the adapters may place differing workloads upon the devices and knowledge regarding the sizes of the workloads may not be shared between the adapters. In this case, when one adapter sends work to a device, it has no knowledge of the amount of work other adapters may also have sent to the device. Hence it can be difficult to predict how long it will be until the work is actually dequeued by thee device and executed. Consequently, in this environment, it is difficult to handle timeouts effectively. If an adapter does not receive timely notification from a device that the work has been completed, it may assume that the device is dead and initiate a system reset. This assumption may however be erroneous as the delay may be due for example to the device processing work from another adapter. Thus command time-out values are difficult to set accurately. One solution to this problem would be to set long time-outs. However, this would delay recovery to an unacceptable degree when there is a genuine malfunction.
Another solution to this problem might involve each adapter being informed by the other adapters of all the commands they have sent to the shared device. Each adapter could use this information to build up an overall picture of activity at the shared device and set the timeouts accordingly. However such a solution will generally not be practicable due to the unacceptable overhead caused by the inter-adapter communication.
It is therefore an object of the invention to provide a time-out management technique which overcomes the disadvantages of the prior art.
According to one aspect of the present invention therefore, there is provided a method for managing devices in a data processing system that includes a plurality of device adapters connected for independent communication with at least one shared device. The method comprises the steps of: issuing a command from a first of the plurality of adapters to the at least one shared device; setting, in the first adapter, first and second timeouts associated with the command; on expiration of the first timeout, issuing a message from said first adapter to other(s) of the plurality of adapters to request the other adapter(s) to notify the first adapter of any work requested of the shared device by the other adapter(s); and on expiration of the second timeout, initiating a recovery operation in the data processing system.
In this way, the problem of erroneous resets described above is avoided by the use of first and second timeouts. On expiry of a first timeout, the system enters a Device Suspicious mode and a message is broadcast to the other adapters connected the shared device to cause each of the other adapter(s) to provide a notification of any work that it (they) initiated at the shared device. If the second timeout expires at the first adapter before receiving any such notification then the first adapter assumes that the device is dead and initiates a recovery action. As will be described below in relation to the preferred embodiment, if notification is received before expiry of the second timeout then the second timeout value is extended. The second timeout may be extended multiple times in response to multiple completion notifications. However an upper limit to the second timeout value will generally be employed in order not to significantly delay a device reset in the event of a device malfunction. As an alternative to extending the second timeout, a third timeout could be set on receipt of each notification.
In the preferred embodiment, the first and second timeouts are set on issuance of the command by the first adapter to the shared device. In an alternative arrangement, the second timeout could be set on expiry of the first timeout.
In the preferred embodiment, the message from the first adapter requests the other adapter(s) to notify the first adapter of the completion of every command that the other adapter(s) have outstanding at the shared device. Thus when the first adapter receives notification from another adapter, it knows that the shared device is still completing work for the other adapter and can therefore extend the second time value in the expectation that the device will subsequently execute the command issued by the first adapter.
In accordance with the preferred embodiment, when the system enters the Device Suspicious mode, the message sent from the first adapter to the other adapter(s) also requests the other adapter(s) to halt sending work to the shared device. The first adapter itself also halts sending work to the shared device. On receipt of the message at each of the other adapter(s), the adapter(s) each issue a Ordered Test Unit Ready command to the shared device. This command joins the command queue at the shared device awaiting execution. When the Ordered Test Unit Ready command reaches the head of the queue, it is executed by the shared device and a completion message is sent to the issuing adapter. Receipt the completion message therefore provides an indication as to when all the outstanding work initiated by the adapter has been completed. At this point, the adapter can restart sending work to the device. Use of the Ordered Test Unit Ready command provides an additional benefit: if the adapter believes that it has work outstanding when it receives a completion message, then it knows that there is a problem with the device itself, with the adapter or with the connecting link. In this case, an appropriate system reset is performed.
In accordance with the preferred embodiment, the values of the first and second timeouts set by the first adapter will vary according to the type of command issued by the first adapter. Thus for a command which normally takes only a few seconds to complete, for example a Disk read command, the first and second timeouts will be relatively short. For a command that normally takes many seconds to complete, for example a device microcode download command, the first and second timeouts will be relatively large.
A preferred feature of the present invention provides additional benefits in the case where the shared device is executing a command from a second adapter that takes a prolonged period to complete, for example a device microcode download. In this scenario, if the first adapter issues a command to the shared device during this prolonged period, then it is possible that the first and second timeouts at the first adapter will expire before the second adapter can provide a notification that its command is complete. To overcome this, when a command is issued from one of the plurality of adapters to the shared device that will cause an operation that takes longer than a predetermined value, the issuing adapter periodically sends false completion notifications to each of the other adapter(s) to prevent expiry of any second timeout value(s) at the other adapter(s).
Viewed from another aspect, the present invention provides a method and apparatus for managing devices in a data processing system that includes a plurality of controllers connected for independent communication with at least one shared device, the at least one shared device maintaining a set, for example a command queue, of commands issued to it by the controllers. In response to a trigger event at a first of the controllers, the first controller sends a request to the other controller(s) to request the other controllers) to provide information regarding work requested of the shared device by the other controllers). The requesting controller employs the received information to build up a picture of the state of the command set at the shared device. This trigger event may be a notification from the shared device that the command queue is full in which case it is advantageous for the controller to acquire information regarding the commands on the queue. The trigger event may instead be the expiration of a timeout (corresponding to the first timeout of the first aspect of the invention) that was set on issuance of an I/O command from the first controller to the shared device.
A preferred embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings.

Managing shared devices in a data processing system

International Business Machines Corporation


An integrated circuit package separator method for separating integrated circuit packages from a board having a plurality of integrated circuits. The method includes providing a base having a plurality of pins, providing a support over the base and having a plurality of holes extending therethrough, the plurality of pins extending through the plurality of holes, vertically displacing the support off the pins using a pair of pneumatic actuators such that each of the pneumatic actuators lift respective opposing ends of the support substantially simultaneously and in unison, providing each of the pneumatic actuators with release valves to equilibrate a back-pressure to ambient during lifting of the support, and separating the integrated circuit packages from one another when the board is over the upper surface of the support.

Circuit constructions having integrated circuit (IC) chips bonded to circuit boards (such as SIMMs and DIMMs) can be fabricated by joining IC chips on a single large circuit board comprising a plurality of the constructions. The circuit board can be subsequently cut to separate discrete constructions from one another. The discrete constructions are referred to herein as integrated circuit packages. The smaller the individual circuit packages, the more likely it is for industry processing to utilize the above-described method of forming the packages on a single large board and subsequently cutting individual packages from the board.
An exemplary prior art process of separating integrated circuit packages is described with reference to FIG. 1. FIG. 1 illustrates a board assembly 10 having a plurality of IC chips 12 (only some of which are labeled) bonded thereto. Chips 12 are aligned into individual IC package configurations 14 (only some of which are labeled) to form a repeating pattern of integrated circuit packages 14 across the board assembly 10. Dashed lines 16 are shown to illustrate the boundaries between individual IC packages 14. In the shown exemplary embodiment, assembly 10 comprises three separate circuit boards 11, 13 and 15. The number and size of individual circuit boards can vary depending on the number and size of IC packages that are ultimately to be formed.
Each of boards 11, 13 and 15 comprises a pair of lateral waste sections 21, 23 and 25, respectively. The lateral waste sections 21, 23 and 25 are separated from the remainder of boards 11, 13 and 15, respectively, by imaginary dashed lines 20, 22 and 24. In further processing, the individual IC packages 14 are separated from one another by cutting through boards 11, 13 and 15 along the regions illustrated by dashed lines 16. During the cutting to separate IC packages 14 from one another, boards 11, 13 and 15 are also cut along regions illustrated by dashed lines 20, 22 and 24 to remove waste portions 21, 23 and 25 from the lateral sides of the boards, and accordingly from lateral edges of the ultimately formed IC packages.
Orifices 19 (only some of which are labeled) are provided throughout circuit boards 11, 13 and 15. Specifically, pairs of orifices 19 are provided in each IC package 14, and at least two orifices 19 are provided in each of waste portions 21, 23 and 25.
FIG. 1 further illustrates an IC package separator 40 comprising a cutting mechanism 42 (shown schematically as a cutting wheel, although other cutting mechanisms, such as, for example, router bits or linear blades, are known to persons of ordinary skill in the art), a retaining table 44, and a control mechanism 45 configured to control orientation of cutting wheel 42 relative to table 44. Retaining table 44 can comprise, for example, an x-y table (i.e., a table horizontally adjustable in x and y directions; an "X", "Y" and "Z" axis system is illustrated in a lower corner of FIG. 1). Control mechanism 45 can control the x and y orientation of table 44 and the z (i.e., vertical) orientation of cutting mechanism 42 to precisely cut a board retained on table 44. Table 44, cutting mechanism 42, and control mechanism 45 can be comprised by commercially available cutting systems, such as, for example, Advanced Technology Incorporated's CM101 single spindle router (or, more generally, a circuit board depanelization router).
FIG. 1 also illustrates that table 44 comprises an upper platform 46. A subplate 48 is provided over platform 46, and a stripper plate 50 is provided over subplate 48. Subplate 48 comprises a plurality of upwardly extending pins 60 (only some of which are labeled), and stripper plate 50 comprises a number of orifices 62 configured to slide over pins 60. Subplate 48 is retained on table 44 by downwardly extending pins (not shown) which are aligned with and precisely received within orifices (not shown) extending within platform 46 of table 44.
Orifices 19 of boards 11, 13 and 15 align with pins 60. In operation, boards 11, 13 and 15 are slid over pins 60 until the pins protrude through orifices 19. Typically, orifices 19 are only about 0.003 inches wider than pins 60 to insure tight alignment of boards 11, 13 and 15 with subplate 48. After boards 11, 13 and 15 are retained on table 44 by pins 60, cutting mechanism 42 is utilized to cut along the regions illustrated by dashed lines 16, 20, 22 and 24. Such cutting separates discrete integrated circuit packages 14 from one another, as well as from waste regions 21, 23 and 25. The separated circuit packages are retained on table 44 by pins 60 extending through the packages. Specifically, each of individual packages 14 comprises a pair of orifices 19 and is thereby retained on table 44 by a pair of pins 60.
After the IC packages are separated from one another, stripper plate 50 is manually lifted off of subplate 48 to lift the IC packages 14 from pins 60. Once stripper plate 50 is lifted off from pins 60, the individual IC packages can be separated from stripper plate 50. An exemplary method of removing the IC packages from stripper plate 50 is to tilt plate 50 and allow the packages to slide off plate 50. After the packages 14 are removed, plate 50 can be returned to over 48 and used again for separating IC packages.
Difficulties can occur in utilizing the assembly of FIG. 1 for separating IC packages. For instance, separated IC packages can be broken as stripper plate 50 is lifted from subplate 48. It would be desirable to reduce or eliminate such problems.

Integrated circuit package separator methods


A method for rendering hair particles includes determining a grid with vertices and voxels bounding the hair particles, determining hair densities for the vertices, smoothing the hair densities, solving a distance function to form a distance field in response to the smooth hair densities, wherein a distance function returns zero at a pre-determined hair particle density, determining a surface normal direction for a hair particle in response to the distance field values, determining a hair illumination value in response to a first illumination source, and determining a shading value for the hair particle using the hair illumination value and the surface normal direction for the hair particle.

The present invention relates to computer animation. More particularly, the present invention relates to techniques and apparatus for efficient rendering of hair on objects.
Throughout the years, movie makers have often tried to tell stories involving make-believe creatures, far away places, and fantastic things. To do so, they have often relied on animation techniques to bring the make-believe to "life." Two of the major paths in animation have traditionally included, drawing-based animation techniques and physical animation techniques.
Drawing-based animation techniques were refined in the twentieth century, by movie makers such as Walt Disney and used in movies such as "Snow White and the Seven Dwarfs" (1937) and "Fantasia" (1940). This animation technique typically required artists to hand-draw (or paint) animated images onto a transparent media or cels. After painting, each cel would then be captured or recorded onto film as one or more frames in a movie.
Physical-based animation techniques typically required the construction of miniature sets, props, and characters. The filmmakers would construct the sets, add props, and position the miniature characters in a pose. After the animator was happy with how everything was arranged, one or more frames of film would be taken of that specific arrangement. Physical animation techniques were developed by movie makers such as Willis O'Brien for movies such as "King Kong" (1933). Subsequently, these techniques were refined by animators such as Ray Harryhausen for movies including "The Mighty Joe Young" (1948) and Clash Of The Titans (1981).
With the wide-spread availability of computers in the later part of the twentieth century, animators began to rely upon computers to assist in the animation process. This included using computers to facilitate drawing-based animation, for example, by painting images, by generating in-between images ("tweening"), and the like. This also included using computers to augment physical animation techniques. For example, physical models could be represented by virtual models in computer memory, and manipulated.
One of the pioneering companies in the computer aided animation (CA) industry was Pixar. Pixar developed both computing platforms specially designed for, computer animation and animation software now known as RenderMan®. RenderMan® was particularly well received in the animation industry and recognized with two Academy Awards®.
RenderMan® software is used to convert graphical specifications of objects and convert them into one or more images. This technique is known in the industry as rendering. One specific portion of the rendering process is known as surface shading. In the surface shading process, the surface shader software determines how much light is directed towards the viewer from the surface of objects in an image in response to the applied light sources. Two specific parameters that are used for shading calculations includes a surface normal and a surface illumination.
The surface shading process is quite effective for coherent surfaces where there are smoothly varying surface properties. However, this process is not effective for shading hair, because hair is typically a large collection of infinitely thin curves (one-dimensional) that have little physical relation to neighboring hairs. Further, this process is not effective because unlike standard surfaces, hair does not have a well-defined surface normal.
Hair illumination processes have been proposed to solve the problem of illuminating a one dimensional hair in a three dimensional world. One such process has included the use of tangent-based lighting response to determine hair illumination, and the use of deep shadows for self-shadowing.
Drawbacks to tangent-based illumination solutions include that this method often leads to visually distracting artifacts. That is, viewers typically expect hair to have smooth illumination across neighboring hairs, but with this method, there is no hair to hair lighting coherency, thus hair will "sparkle" or "pop" to a viewer. Another drawback is that unrelated hairs that are spatially far apart may erroneously have the same lighting response. For example, in the case of back-lit head, if a hair on the front of a head and a hair on back of the head have the same tangent, they will have the same illumination. As a result, even though the head is supposed to be silhouetted, hairs on the front the head will be still be illuminated.
Drawbacks to the use of deep shadows for hair self-shadowing include that they are computationally intensive, and they are inflexible. As is known, deep shadows maps are computed separately for each illumination source, and for a specific illumination position. If an animator decides to change the position of the camera, the entire deep shadow map for that illumination source will need to be recomputed. Yet another drawback is that because hair is computationally expensive to shade, a hair model having fewer hairs may used. However, if the hair is back-lit, the thinness of the hair model will be apparent to a viewer.
In light of the above, what is needed are improved techniques to render hair without the visual problems described above.


The object of the invention is to provide an equalizer capable of generating an equalized output compensated in the non-linearity of the signal reproduced by an MR head and a reliable high-density magnetically recorded-signal reproducer. An equalizer of an FIR-type filter structure comprises a plurality of delay elements for delaying input signals by a certain period, a plurality of coefficient processing units provided to input or output taps of the delay elements, and an adder for obtaining the sum of the outputs of the coefficient processing units, in which the distortion of the reproduced waveform can be corrected by a relatively simple circuit structure by comparing the signal value inputted to the coefficient processing unit from each tap with a predetermined threshold level and changing the signal value and a coefficient value to be multiplied in accordance with the comparison result. Therefore, any one of various existing signal processing systems can be applied to the decoding of reproduced signals of an MR head having the non-linear characteristic.

The present invention relates to an equalizer and a magnetically recorded-signal reproducer, more particularly to an equalizer suitable for the processing of a reproduced signal by an MR-type read head and a magnetically recorded-signal reproducer using the MR-type read head.
In a magnetic disk drive, the sensitivity of a read head has been improved to increase the density and a read head (hereafter referred to as MR head) using the magnetoresistance effect has been developed instead of conventional inductive heads.
The flux-to-reproduced voltage conversion characteristic of the MR head is shown by the curve 76 of FIG. 11. The operating area of the MR head 74 is set to the linear portion of the characteristic 76 by superposing a bias field 73 on an input field 71 sent from a magnetic recording medium with information recorded. In this case, non-linearity represented by amplitude asymmetry appears on the reproduced waveform 72 due to the deviation of the bias field or the variation of the magnetic characteristics. In general, the circuits of the signal processing system of a magnetic disk drive is designed assuming that a magnetically recorded-signal reproducing system including a write head and a read head Ls linear. Therefore, the non-linearity which appears in the operating area of the MR head causes the performance of the magnetic disk drive to greatly deteriorate.
In a conventional disk drive, the non-linearity of the MR head is linearly equalized by the FIR-type equalizer shown in FIG. 2.
The FIR-type equalizer comprises a plurality of delay elements 1 (1-1 to 1-n) multistagea-connected to delay the input signal by one bit in time, a plurality of coefficient processing units (2-0 to 2-n) connected to the input signal tap at the first stage and the output signal tap at each stage, and an adder 10 for adding the outputs of the coefficient processing units. The coefficient processing unit 2-i multiplies the tap output 11-i by a predetermined tap coefficient. When the input signal waveform of a tap output has a distortion, each coefficient processing unit performs a linear operation of the distorted signal and therefore, it is difficult to completely compensate the above non-linearity. Therefore, to prevent performance deterioration, an idea for correcting the non-linearity of a reproduced signal before the signal is input to an equalizer has been proposed.
In U.S. Pat. No. 5,418,660, for example, a system is proposed which corrects the amplitude asymmetry of the reproduced waveform supplied to an equalizer by setting an A-D conversion scale to a different value in accordance with the polarity (positive or negative) of the input signal in an A-D converter for supplying the input to the equalizer.
In Japanese Patent Laid-Open No. 441510/1994, a method is proposed according to which the amplitude value is corrected (converted) by converting the reproduced signal output from an MR head from analog to digital values and thereafter using a look-up table. In the above proposals, the conversion characteristic of the amplitude value to be set in the look-up table is obtained by measuring the characteristics of each MR head while previously changing the bias field of the MR head. When the characteristic of an MR head is changed, fitting is performed in accordance with the data stored in the table.
Moreover, in Japanese Patent Laid-Open No. 266403/1993, a method is proposed which reduces the deterioration due to non-linearity by optimizing the equalization target of an FIR filter.
Furthermore, there is an idea of improving non-linearity including non-linear transition shift by using an equalizer constituted by incorporating a RAM into a decision feedback equalizer.
However, according to the conventional system for correcting MR non-linearity before the input of an equalizer, complicated characteristic are necessary for a canceler in order to completely remove non-linearity and therefore, a problem arises that the circuit is increased in size and the fabrication cost rises because the structure of the arithmetic circuit is complicated and the memory capacity is increased. Moreover, according to the conventional system, the circuit delay of an additional circuit provided in the reproduced signal path adversely affects the feed loop system for phase locked loop (PLL) and automatic gain control (AGC). Furthermore, according to a system of correcting MR non-linearity by an A-D converter, it is difficult to accurately fabricate an LSI because the applied voltages and loads of circuit elements constituting the A-D converter change when the reference voltage is changed to change the scaling. Moreover, to change the scaling by the reference voltage of the A-D converter, the correction coefficient becomes an analog value and thereby, accurate correction is difficult due to variations in circuit elements.

Equalizer having a processing unit for selecting a coefficient out of a coefficient table


A system for collecting and analyzing equipment telematic data typically includes a processor, a memory, and an analysis module stored in the memory. The analysis module is typically configured for: receiving telematic data from a piece of equipment; parsing the telematic data to identify (i) location information and (ii) usage information for one or more tools; analyzing the telematic data to determine whether a job site condition has been satisfied; in response to determining that the job site condition has been satisfied, identifying a first job site location based on the location information of the telematic data; determining that the first job site location is not within an existing job site; and updating a job site database to include the first job site location.

In many fields, such as electrical line work, construction, mining, oil or gas drilling, farming, fishing, and the like, it may be desirable to track the time equipment and personnel are performing work at a job site, as opposed to time spent performing other activities, such as traveling, collecting materials at a yard, and taking meal breaks. Accordingly, a need exists for an improved way of tracking the time equipment and personnel are performing work at a job site.

System for collecting and analyzing equipment telematic data


A beacon light optic, comprising a reflective surface having an optical axis wherein the reflective surface is composed of surface parts of at least two at least partly overlapping at least segments of rotation symmetrical surfaces, an entrance area comprising an entrance surface for allowing light to enter the beacon light optic, an exit area through which light exits the beacon light optic, a light emitting element disposed in front of the entrance surface such that light emitting from the light emitting element enters the beacon light optic through the entrance area.

Beacon lights are known and one of the typical requirements is to transmit a bundle of light over a relatively wide angle, typically 360 degrees, in a horizontal plane over a relatively small vertical angle, i.e. with a limited beam spread, to provide an obstruction warning in all directions. The definition of beam spread depends on the regulations to be applied. A common rule is to consider the beam spread at full width half maximum (FWHM). The beam spread is then considered to be the angle of the full width of the beam at half the maximum of the peak intensity. Typically the beam spread is the angle of the beam measured in a vertical plane over which the intensity of the emitted light is greater than e.g. 50%—depending on the regulations this may be 10%—of the peak intensity of the emitted light. The beam spread may typically be on the order of several degrees, e.g. 5 degrees or 2.5 degrees. For certain applications such as offshore obstruction lights or aviation obstruction lights, the desired pattern of emitted light is defined by rules and/or regulations.
A typical beacon light comprises a plurality of beacon light optics arranged in juxtaposition such that the optical axes of the beacon light optics are angled relative to each other and the exit areas of the beacon light optics face outwards. The beacon light optic usually is of a rotation symmetrical type, e.g. a paraboloid and may be a massive optic or an air-filled optic. A massive optic can be a massive plastic optic or a massive glass optic. Each optic typically comprises a single light emitting element, preferably an LED-element.
A drawback of the known beacon light is that a lot of optics are needed to form a beacon light with a 360 degrees angular distribution. Since an individual beacon light optic is relatively expensive, and relatively heavy, the beacon light may become relatively large, expensive and/or difficult to install.
Therefore, there is a need for a beacon light that can be more cost effective and/or more compact.
Furthermore, each light emitting element consumes energy, and, in particular for systems operating on batteries in case of emergency, energy consumption of the beacon light is preferably as low as possible, because less energy consumption also means a smaller battery pack. Since the batteries used for these emergency purposes are relatively expensive, there is a wish to minimize the battery pack required.
Thereto, an embodiment provides a beacon light optic according to claim 1.

Beacon light optic, beacon light, method for obtaining a beacon light optic


A fuel injection control device for an internal combustion engine, includes a rotational speed sensor for detecting rotational speed of the internal combustion engine, intake air quantity sensor for detecting an air quantity taken into the internal combustion engine, atmospheric pressure sensor for detecting atmospheric pressure, and an engine control unit for estimating an inlet pipe pressure of the internal combustion engine from the detected rotational speed and intake air quantity, computing a fuel injection quantity fuel pressure correction coefficient according to a difference between the estimated inlet pipe pressure and the detected atmospheric pressure, and correcting a fuel injection quantity based on the computed fuel injection quantity fuel pressure correction coefficient.

This application is based on Application No. 2002-005911, filed in Japan on Jan. 15, 2002, the contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a fuel injection control device for an internal combustion engine, and particularly to a fuel injection control device for an internal combustion engine in a fuel returnless system.
2. Description of the Related Art
FIG. 9 is a block diagram showing a conventional fuel injection control device for an internal combustion engine in a fuel returnless system.
In the figure, reference numeral 1 denotes an internal combustion engine, reference numeral 2 denotes a cylinder, reference numeral 3 denotes a piston, reference numeral 4 denotes a cylinder head, reference numeral 5 denotes a combustion chamber, reference numeral 6 denotes an engine control unit, reference numeral 7 denotes an inlet port, reference numeral 8 denotes an inlet valve, reference numeral 9 denotes an exhaust port, reference numeral 10 denotes an exhaust valve, reference numeral 11 denoted an injector (fuel injection valve), reference numeral 12 denotes a sparking plug, reference numerals 13 and 14 denote actuators, reference numeral 15 denotes a fuel tank, reference numeral 16 denotes a fuel pressure regulator, reference numeral 17 denotes a fuel pipe, reference numeral 18 denotes an inlet manifold, reference numeral 19 denotes an inlet pipe pressure sensor, reference numeral 20 denotes an atmospheric pressure sensor, reference numeral 21 denotes a fuel pump, and reference numeral 22 denotes a delivery pipe.
The engine control unit 6 includes correction coefficient computation means for computing a fuel injection quantity correction coefficient according to a difference between an inlet pipe pressure and an atmospheric pressure detected by the inlet pipe pressure sensor 19 and the atmospheric sensor 20, and fuel injection amount correction means for correcting a fuel injection quantity according to the fuel injection quantity correction coefficient, and it drives the injector 11 in the corrected fuel injection quantity.
In the above-described conventional controller, a volume intake air quantity equivalent value is obtained by an inlet pipe pressure detected by the inlet pipe pressure sensor, but an error from an actual mass intake air quantity sometimes occurs due to influences of intake air temperature, exhaust recirculation gas (EGR) and the like, and when an accurate intake air quantity is to be measured, it is necessary to provide an intake air quantity sensor. However, in this case, if conventional correction of fuel pressure is to be carried out based on the inlet pipe pressure and the atmospheric pressure detected by the inlet pipe pressure sensor and the atmospheric sensor, the inlet pipe pressure sensor, which becomes unnecessary as a result that air quantity measurement with high accuracy is performed, is needed again, whereby the system becomes expensive.
If the correction of the fuel injection quantity based on fuel pressure according to the difference between the inlet pipe pressure and the atmospheric pressure is not carried out in the fuel injection control device using the intake air quantity sensor to measure the above-described intake air quantity with high accuracy, accuracy of the fuel injection quantity reduces sharply.
When exhaust gas recirculation equipment, a variable valve timing mechanism and the like are provided in a fuel injection control device using the intake air quantity sensor as described above, even if the same quantity of mass intake air is detected in the intake air quantity sensor, the inlet pipe pressure changes according to the quantities of an outer exhaust recirculation gas by the exhaust gas recirculation equipment and an inner exhaust recirculation gas by the variable valve timing mechanism. In this case, accuracy of a fuel injection quantity reduces sharply, if the correction of the inlet pipe pressure estimated with rotational speed and filling efficiency, which is used for fuel pressure correction, by exhaust gas recirculation control quantity and variable valve timing control quantity is not carried out and the correction of the fuel injection quantity by fuel pressure using the corrected inlet pipe pressure is not carried out.
The present invention is made to eliminate the above-described disadvantage, and its object is to provide a fuel injection control device for an internal combustion engine that is less expensive with high accuracy.
The fuel injection control device for the internal combustion engine according to the invention is a fuel injection control device for an internal combustion engine for supplying fuel at a constant pressure to an injector of each cylinder via a fuel pipe and a delivery pipe by a fuel pump and a fuel pressure regulator disposed in a fuel tank of the internal combustion engine, and includes rotational speed detection means for detecting rotational speed of the aforesaid internal combustion engine, intake air quantity detection means for detecting an air quantity taken into the aforesaid internal combustion engine, atmospheric pressure detection means for detecting atmospheric pressure; and correction means for estimating an inlet pipe pressure of the internal combustion engine from the detected rotational speed and intake air quantity, computing a fuel injection quantity fuel pressure correction coefficient according to a difference between the estimated inlet pipe pressure and the aforementioned detected atmospheric pressure, and correcting a fuel injection quantity based on the computed fuel injection quantity fuel pressure correction coefficient.
The fuel injection control device for the internal combustion engine according to the invention includes control means for controlling a recirculation quantity of exhaust gas recirculation equipment, and the aforesaid correction means corrects the inlet pipe pressure estimated from the detected rotational speed and intake air quantity according to the aforementioned recirculation quantity, computes the fuel injection quantity fuel pressure correction coefficient according to the difference between the corrected inlet pipe pressure and the detected atmospheric pressure, and corrects the fuel injection quantity according to the computed fuel injection quantity fuel pressure correction coefficient.
The fuel injection control device for the internal combustion engine according to the invention includes control means for controlling a variable valve timing of a variable valve timing mechanism, and the aforesaid correction means corrects the inlet pipe pressure estimated from the aforementioned detected rotational speed and intake air quantity according to the aforementioned variable valve timing, computes the fuel injection quantity fuel pressure correction coefficient according to the difference between the corrected inlet pipe pressure and the aforementioned detected atmospheric pressure, and corrects the fuel injection quantity according to the computed fuel injection quantity fuel pressure correction coefficient.
The fuel injection control device for the internal combustion engine according to the invention is a fuel injection control device for an internal combustion engine for supplying fuel at a constant pressure to an injector of each cylinder via a fuel pipe and a delivery pipe by a fuel pump and a fuel pressure regulator disposed in a fuel tank of the internal combustion engine, and includes rotational speed detection means for detecting rotational speed of the aforesaid internal combustion engine, intake air quantity detection means for detecting an air quantity taken into the aforesaid internal combustion engine, throttle valve travel detection means for detecting an valve travel of a throttle valve of the aforesaid internal combustion engine, inlet pipe pressure detection means for detecting an inlet pipe pressure of the aforesaid internal combustion engine, and correction means for estimating atmospheric pressure from the detected inlet pipe pressure, rotational speed, throttle valve travel and intake air quantity, computing a fuel injection quantity fuel pressure correction coefficient according to a difference between the estimated atmospheric pressure and the aforesaid detected inlet pipe pressure, and correcting a fuel injection quantity according to the computed fuel injection quantity fuel pressure correction coefficient.
The fuel injection control device for the internal combustion engine according to the invention is a fuel injection control device for an internal combustion engine for supplying fuel at a constant pressure to an injector of each cylinder via a fuel pipe and a delivery pipe by a fuel pump and a fuel pressure regulator disposed in a fuel tank of the internal combustion engine, and includes rotational speed detection means for detecting rotational speed of the aforesaid internal combustion engine, intake air quantity detection means for detecting an air quantity taken into the aforesaid internal combustion engine, throttle valve travel detection means for detecting an valve travel of a throttle valve of the aforesaid internal combustion engine, and correction means for estimating atmospheric pressure from the detected rotational speed, throttle valve travel and intake air quantity and estimating an inlet pipe pressure of the internal combustion engine from the aforementioned detected rotational speed and intake air quantity, computing a fuel injection quantity fuel pressure correction coefficient according to a difference between the estimated atmospheric pressure and inlet pipe pressure, and correcting a fuel injection quantity according to the computed fuel injection quantity fuel pressure correction coefficient.

Fuel injection control device for internal combustion engine


The present invention concerns a process and an apparatus for continuous polymerisation of olefin monomers. In particular, the present invention concerns a process and an apparatus for continuous polymerisation olefin monomers like ethylene and other monomers, wherein an olefin monomer is polymerised in slurry phase in an inert hydrocarbon diluent in at least one loop reactor. According to the invention, a polymer slurry is continuously withdrawn from the loop reactor and concentrated. The concentrated slurry is conducted to a flash unit in order to remove the remaining fluid phase, and gas obtained is compressed in a flash gas compressor before it is being fed to a distillation section. By means of the present invention it is possible reduce the size of the flash gas compressor and the capacity of the distillation sections. This significantly reduces investment cost for a continuously operated polymerization apparatus.

1. Field of the Invention
The present invention relates to olefin polymerisation. In particular, the present invention concerns a process and an apparatus for continuous polymerisation olefin monomers like ethylene and other monomers, wherein an olefin monomer is polymerised in slurry phase in an inert hydrocarbon diluent in at least one loop reactor.
2. Description of Related Art
The loop reactor was developed in the 1950's. It is now widely used for the production of polyethylene and other olefin polymers. In a loop reactor, ethylene is polymerised in the presence of a hydrocarbon diluent in slurry phase at elevated pressure and temperature. The slurry is withdrawn from the reactor and concentrated so that the solids content at the reactor outlet is higher than the solids content in the reactor. Traditionally, this has been done by using settling legs. However, present methods for concentrating the polymer slurry of a loop reactor have been unsatisfactory. This is true, in particular, for the production of bimodal polyethylene in cascaded reactors.
The use of hydrocyclones for concentrating the outlet slurry of a loop reactor is known since the 1960's. Loop reactors equipped with a hydrocyclone are disclosed in, e.g., U.S. Pat. No. 3,816,383, where a part of the underflow from the hydrocyclone is taken to product recovery, while the residual part is combined with the overflow and returned to the loop reactor.
Another document relating to the above-mentioned topic is U.S. Pat. No. 4,395,523, which discloses a method of making and recovering polymer particles. The known method comprises polymerising in a loop reactor, directing a portion of the recirculating polymer slurry into a hydrocyclone, returning the overflow from the hydrocyclone into the reactor and withdrawing the underflow from the hydrocyclone and conducting it to product recovery.
Further, EP 1 118 624, EP 1 118 625 and EP 1 118 626 disclose a process for polymerising olefins, where the polymer slurry is directed from a loop reactor into a hydrocyclone. The underflow from the hydrocyclone is directed either to a subsequent polymerisation stage or to product recovery.
EP 891 990 discloses an ethylene polymerisation process comprising a continuous take-off of polymer slurry. The polymer slurry is continuously withdrawn from the loop reactor and fed to a high-pressure flash. From the high-pressure flash, the polymer is transferred into a low-pressure flash and from there to product recovery.
Even if the above documents describe different methods of withdrawing the slurry from the loop reactor, none of them discloses or suggests a polymerization method or apparatus, where the size of the separation units can be kept small compared to the product flows.

Process and apparatus for producing olefin polymers


A variable damper assembly 10 is provided for use with a vehicle power steering system and includes a variable orifice valve 20 which controls the flow of fluid between one chamber side 30 of the damper assembly to another chamber side 32 of the damper assembly. Variable orifice valve 20 is communicatively coupled to a source of pressurized fluid 110 by use of a conduit 112 and an electronically controlled valve assembly 114. The pressurized fluid received through conduit 112 controls the operation of valve 20. Based upon the pressure of the received fluid, valve 20 selectively increases and reduces the fluid flow rate between chamber sides 30 and 32, thereby causing the damper assembly 10 to have enhanced damping characteristics during certain vehicle operating conditions (e.g., during relatively high vehicle speed operating conditions).

This invention relates to a variable damper assembly and more particularly, to a variable damper assembly for use with a vehicle steering system and which includes an electronically controlled variable orifice valve which allows the damping characteristics of the damper assembly to be selectively and controllably altered based upon the speed and steering wheel angle of the vehicle.
Damper assemblies are typically used within a vehicle steering assembly to reduce the forces that are transmitted to the steering wheel that may result from irregularities in the road surface. In this manner, damper assemblies improve impact feel and reduce steering xe2x80x9cshimmyxe2x80x9d and xe2x80x9cnibblexe2x80x9d.
Damper assemblies provide a damping force which varies based upon the velocity of the damper according to a certain function, relationship or curve. Conventional damper assemblies typically have a single force versus velocity function or curve which does not vary based upon vehicle speed or other parameters. As a result, conventional damper assemblies have either a relatively high force/velocity curve which provides high damping of impacts while compromising steering effort, or have a relatively low force/velocity curve which maintains power steering effort at a desirable level, but does not substantially reduce steering shimmy and nibble.
There is therefore a need for a variable damper assembly which provides maximum impact resistance and shimmy and nibble reduction at relatively high vehicle speeds and neutral steering positions, while providing sufficient power steering capabilities at relatively low speeds and during parking maneuvers.
A first advantage of the invention is that it provides a variable damper assembly for use with a vehicle steering system which overcomes some or all of the previously delineated drawbacks of prior damper systems and assemblies.
A second advantage of the invention is that it provides a variable damper assembly for use with a vehicle steering system which includes an electronically controlled variable orifice valve which provides for force-velocity relationships which are selectively variable based upon vehicle speed and steering wheel angle data.
A third advantage of the present invention is that it provides a variable damper assembly for a vehicle steering system which allows the damping characteristics of the damper assembly to be selectively and controllably altered based upon the speed and steering wheel angle of the vehicle.
A fourth advantage of the present invention is that it provides a variable damper assembly for a vehicle steering system which provides relatively high damping at high vehicle speeds and relatively high power steering effort at low vehicle speeds and during parking maneuvers.
According to a first aspect of the present invention, a variable damper assembly is provided and includes a cylinder which forms a chamber containing an amount of fluid; a piston which is slidably disposed within the chamber and which is effective to divide the chamber into a first side and a second side; and a variable orifice valve which is fluidly coupled to the first the and the second side of the chamber and which allows a certain amount of pressurized fluid to flow between the first and the second side of the chamber, the variable orifice valve having a variable volume fluid flow path which is effective to selectively increase and decrease the fluid flow rate between the first and second sides of the chamber, thereby selectively altering the damping characteristics of the damper assembly.
These and other objects, aspects, features, and advantages of the present invention will become apparent from a consideration of the following specification and the attached drawings.