This invention relates to the chemical design and production of peptides, peptide structure and three dimensional conformation was assessed using NMR, circular dichroisin and pulsed field gradient NMR. In addition, this invention relates to peptides produced by these methods and to methods for using the peptides.

This invention relates to the fields of chemical design and to methods for selecting, modifying, and creating synthetic chemical structures and to their methods of use.
A critical feature of a polypeptide is its ability to fold into a three dimensional conformation or structure. Polypeptides usually have a unique conformation which, in turn, determines their function. The conformation of a polypeptide has several levels of structure. The primary structure is a linear sequence of a series of amino acids linked into a polypeptide chain. The secondary structure describes the path that the polypeptide backbone of the polypeptide follows in space, and the tertiary structure describes the three dimensional organization of all the atoms in the polypeptide chain, including the side groups as well as the polypeptide backbone.
Covalent and noncovalent interactions between amino acids determine the conformation of a polypeptide. The most common covalent bond used in establishing the secondary and tertiary structure of a polypeptide is the formation of disulfide bridges between two cysteine residues (forming cysteine). The formation of noncovalent bonds is influenced by the aqueous environment such as water. A large number of noncovalent interactions, such as van der Waals, ionic, hydrophobic and hydrogen-bonded interactions, contribute to the way in which a polypeptide folds. Hydrophobic interactions, which occur between amino acids with nonpolar side chains, are particularly important because they associate to exclude water. These side chains generally form the core of the polypeptide, where they are mostly inaccessible to water.
The secondary structure of polypeptides can be divided into two general classes: xcex1-helix and xcex2-sheet. An xcex1-helix is stabilized by hydrogen bonding and side chain interactions between amino acids three and four residues apart in the same polypeptide chain, whereas a xcex2-sheet is stabilized by hydrogen bonding and side chain interactions between amino acids more distant in a polypeptide chain and in different polypeptide chains. A complete understanding of the construction of xcex1 helices and xcex2 sheets is important for the manipulation of the structure and function of polypeptides.
A major challenge in de novo polypeptide design (more often referred to as de novo peptide design), which is the design of polypeptides (or peptides) from scratch, is the engineering of a polypeptide having the folding stability of the native structure of a natural polypeptide. Several polypeptides have been designed with the xcex1 helix as the major structural element. Few polypeptides have been designed with the xcex2 sheet as the major structural element. Unlike xcex1 helices where there is a regular succession of hydrogen bonds between amides three and four residues apart in the sequence, xcex2 sheets are formed by residues at variable and often distant positions in the sequence. In addition, they tend to form aggregates in solution and precipitate under physiological conditions. A major difficulty in designing a structurally stable xcex2 polypeptide is dealing with the interactions between xcex2 sheets.
Designing a polypeptide to form a xcex2-sheet has in the past usually been based on one of a number of structural propensity scales known in the art. These scales are derived either statistically from structural databases of known folded polypeptides or by making single or minimal site-specific changes in a fully folded polypeptide. See, for example, C. A. Kim, et al., Nature, 362, 267 (1993); D. L. Minor, et al., Nature, 371, 264 (1994); D. L. Minor, et al., Nature, 367, 660 (1994); and C. K. Smith, et al., Biochemistry, 33, 5510 (1994). However, such scales are generally less useful when designing de novo xcex2-sheet folds in short peptides where considerably more xcex2-sheet and/or side-chain surface (particularly hydrophobic surface) will be exposed to water. D. E. Otzen, et al., Biochemistry, 34, 5718 (1995).
Betabellin was one of the first de novo designed class of xcex2-sheet peptides. J. Richardson, et al., Biophys. J., 63, 1186 (1992). It was intended to fold into a sandwich of two identical four-stranded, antiparallel xcex2 sheets. A more recent version of betabellin, betabellin 14D, was designed by Yan, et al., Protein Science, 3, 1069, (1994). Quinn, et al. designed betadoublet, which is similar to betabellin but contains only naturally encoded amino acids. T. P. Quinn, et al., Proc. Natl. Acad. Sci. U.S.A., 91, 8747 (1994).
However, peptides in the betabellin and betadoublet series show limited solubility in water and minimal, highly transient xcex2-sheet structure, i.e., nonstable structures. The best betabellin made thus far, Betabellin peptide 14D, for example, becomes less soluble at pH values above 5.5 making it impractical for use at a physiological pH. Moreover the xcex2-sheet structure formed by peptide 14D relies on the presence of an intermolecular disulfide bridge to yield a dimeric species. The peptides of the present invention do not have these limitations. Betadoublet, which has the same predicted antiparallel xcex2-sheet motif as betabellin, is even less water soluble, and only at a lower pH of about 4, and fails to show any compact, stable folding, i.e., structure.
Water solubility and pH ranges are important to peptide function. A polypeptide that is not soluble under physiological conditions (i.e., in water at a pH of about 7.0-7.4 and in about 150 mM NaCl or an equivalent physiological salt) is not functional and is therefore not useful. Neither the betabellin nor the betadoublet strategies for peptide design achieved sufficient solubility, peptide compactness, or peptide self-association under physiological conditions.
Hence, there remains a need for xcex2-sheet forming peptides that are not only water soluble, but soluble at physiological conditions, and self associate.
Sepsis syndrome continues to be one of the leading causes of mortality in critically ill patients and gram-negative bacterial pathogens cause about ⅓ of these cases. Despite intensive laboratory and clinical investigation, the mortality associated with gram-negative bacterial sepsis and shock remains at about 40%, a statistic that has changed little over time. Lipopolysaccharide (LPS, or endotoxin) is an integral component of the outer membrane of gram-negative bacteria and triggers activation of macrophages that, in turn synthesize and secrete cytokines within the endogenous tissue milieu and systemic circulation. The resultant release of tumor necrosis factor-xcex1 (TNF-xcex1) and other cytokines by macrophages is causally linked to the host inflammatory response and the subsequent development of septic shock. Unfortunately, standard inflammatory response and the subsequent development of sepsis and shock, including administration of potent antibiotics, aggressive fluid resuscitation, hemodynamic monitoring, and metabolic support, has not been associated with a significant reduction in mortality.
A 27 amino acid synthetic peptide based on amino acids 82-108 of BPI significantly inhibited TNF-xcex1 secretion in vitro and administration of the peptide in animal models diminished endotoxin levels, although abrogation of TNF-xcex1 secretion was incomplete (Battafarano et al. Surgery 118:318-324, 1995 and Dahlberg, et al. J. Surg. Res. 63:44-48, 1996). The effect of anti-endotoxin monoclonal antibodies HA-1A and E5 on mortality during sepsis syndrome has been studied by phase III clinical trial. In these studies, mortality rates were not reduced as compared to placebo treatments (The CHESS trial study group, Ann. Int. Med. 121:1-5, 1994; Bone et al. Crit. Care Med. 23:994-1005, 1995). Accordingly, novel reagents are needed to treat gram-negative bacterial infections.
Tumor growth can be controlled by deprivation of vascularization (see Folkman, Natl. Cancer. Inst. 82:, 4-6, 1990 and Folkman et al. J. Biol. Chem. 267:10931-10934, 1992). A growing number of endogenous inhibitors of angiogenesis include platelet factor-4 (PF4, Gupta et al. Proc. Natl. Acad. Sci. USA 92:7799-7803, 1995), interferon-xcex3 inducible protein-10 (IP-10, Luster, et al. J. Exp. Med. 182:219-231, 1995), as well as synthetic agents including thalidomide, metalloproteinase inhibitors, and the like. There is a need for reagents to inhibit angiogenesis including agents that inhibit endothelial cell proliferation for a variety of applications, including, but not limited to tumorigenesis.
The present invention provides a method for synthesizing a water-soluble peptide having at least about 35% amino acids having hydrophobic side chains, the method comprising combining amino acids having charged side chains and amino acids having noncharged polar side chains with amino acids having hydrophobic side chains, wherein the amino acids having charged side chains are provided in a ratio of at least about 2:1 amino acids having positively charged side chains to amino acids having negatively charged side chains.
The present invention also provides a method for synthesizing a water-soluble peptide having at least about 35% amino acids having hydrophobic side chains, the method comprising combining amino acids having charged side chains and less than about 20% amino acids having noncharged polar side chains with amino acids having hydrophobic side chains, wherein: the amino acids having charged side chains are provided in a ratio of at least about 2:1 amino acids having positively charged side chains to amino acids having negatively charged side chains; the water-soluble peptide has about 35% to about 55% amino acids having hydrophobic side chains; and at least two of the amino acids having hydrophobic side chains are positioned in the peptide with an intervening turn sequence in a manner such that the two amino acids having hydrophobic side chains are capable of aligning in a pairwise fashion to form a xcex2-sheet structure; and the turn sequence is LXXGR, wherein each X is independently selected from the group consisting of K, N, S, and D. Herein, percentages are reported as the number of specified amino acids relative to the total number of amino acids in the peptide chain.
This invention also relates to a series of xcex2pep peptides prepared using the methods of this invention. These peptides are provided as xcex2pep-1 through xcex2pep-30 and correspond to SEQ ID NO:1 through SEQ ID NO:30. This invention also relates to a method for treating a bacterial infection or endotoxic shock comprising administering an amount of a pharmaceutical composition effective to inhibit the bacterial infection or neutralize endotoxin to a mammal, wherein the pharmacutical composition comprises (a) a peptide demonstrating bactericidal activity or endotoxin neutralizing activity selected from the group consisting of xcex2pep-1 through xcex2pep30 (SEQ ID NO: 1 through SEQ ID NO:30); and (b) a pharmaceutically acceptible carrier.
In one embodiment, the peptide neutralizes endotoxin, in another the peptide is bactericidal and in another the peptide is both bactericidal and neutralizes endotoxin. In a preferred embodiment, the peptide has endotoxin neutralizing acitivity and is selected from the group consisting of xcex2pep-8 and xcex2pep-23. In another preferred embodiment, the peptide has bactericidal activity and is selected from the group consisting of xcex2pep-19, xcex2pep-7, xcex2pep-4, xcex2pep-22 and xcex2pep-1.
This invention also relates to a method for inhibiting TNF-xcex1 levels in a mammal comprising the step of administering a therapeutically effective amount of a pharmaceutical composition comprising: (a) a peptide demonstrating bactericidal activity or endotoxin neutralizing activity selected from the group consisting of xcex2pep-1 through xcex2pep30 (SEQ ID NO: 1 through SEQ ID NO:30); and (b) a pharmaceutically acceptible carrier. In a preferred embodiment the peptide is xcex2pep-3.
This invention also relates to a method for inhibiting endothelial cell proliferation comprising the step of administering an effective amount of a composition comprising: a peptide demonstrating endothelial cell proliferation inhibition selected from the group consisting of xcex2pep-1 through xcex2pep-30 (SEQ ID NO: 1 through SEQ ID NO:30). In one embodiment, the composition is a therapeutically effective amount of a pharmaceutical composition comprising: a peptide selected from the group consisting of xcex2pep-14 or xcex2pep-16; and a pharmaceutically acceptible carrier.
The invention also relates to a method for promoting inter-cellular adhesion molecule (ICAM) expression comprising the step of administering an effective amount of a composition comprising: a peptide promoting inter-cellular adhesion molecule expression selected from the group consisting of xcex2pep-1 through xcex2pep-30 (SEQ ID NO:1 through SEQ ID NO:30).
xe2x80x9cAmino acidxe2x80x9d is used herein to refer to a chemical compound with the general formula: NH2xe2x80x94CRHxe2x80x94COOH, where R, the side chain, is H or an organic group. Where R is organic, R can vary and is either polar or nonpolar (i.e., hydrophobic). The amino acids of this invention can be naturally occurring or synthetic (often referred to as nonproteinogenic). As used herein, an organic group is a hydrocarbon group that is classified as an aliphatic group, a cyclic group or combination of aliphatic and cyclic groups. The term xe2x80x9caliphatic groupxe2x80x9d means a saturated or unsaturated linear or branched hydrocarbon group. This term is used to encompass alkyl, alkenyl, and alkynyl groups, for example. The term xe2x80x9ccyclic groupxe2x80x9d means a closed ring hydrocarbon group that is classified as an alicyclic group, aromatic group, or heterocyclic group. The term xe2x80x9calicyclic groupxe2x80x9d means a cyclic hydrocarbon group having properties resembling those of aliphatic groups. The term xe2x80x9caromatic groupxe2x80x9d refers to mono- or polycyclic aromatic hydrocarbon groups. As used herein, an organic group can be substituted or unsubstituted. One letter and three letter symbols are used herein to designate the naturally occurring amino acids. Such designations including R or Arg, for Arginine, K or Lys, for Lysine, G or Gly, for Glycine, and X for an undetermined amino acid, and the like, are well known to those skilled in the art.
The term xe2x80x9cpeptidexe2x80x9d or xe2x80x9cpolypeptidexe2x80x9d is used herein to refer to an amino acid polymer. A single peptide of this invention preferably has at least 20 amino acids. Preferably the peptides of this invention are no greater than 50 amino acids in length, and more preferably about 28 to about 33 amino acids in length.
The term xe2x80x9cwater-solublexe2x80x9d is used herein to refer to compounds, molecules, and the like, including the peptides of this invention, that are preferably readily dissolved in water. The compounds of this invention are readily dissolved in water if about 1 mg of the compound dissolves in 1 ml of water having a temperature of about 35-45xc2x0 C. More preferably, the peptides of this invention will have a water solubility of at least about 10 mg/ml and often of at least about 20 mg/ml. Even more preferably, the peptides are soluble at these concentrations under physiological conditions, including a pH of about 7.0-7.4 and a salt concentration of about 150 mM NaCl.
The term xe2x80x9chydrophobic amino acid side chainxe2x80x9d or xe2x80x9cnonpolar amino acid side chain,xe2x80x9d is used herein to refer to amino acid side chains having properties similar to oil or wax in that they repel water. In water, these amino acid side chains interact with one another to generate a nonaqueous environment. Examples of amino acids with hydrophobic side chains include, but are not limited to, valine, leucine, isoleucine, phenylalanine, and tyrosine.
The term xe2x80x9cpolar amino acid side chainxe2x80x9d is used herein to refer to groups that attract water or are readily soluble in water or form hydrogen bonds in water. Examples of polar amino acid side chains include hydroxyl, amine, guanidinium, amide, and carboxylate groups. Polar amino acid side chains can be charged or noncharged.
The term xe2x80x9cnoncharged polar amino acid side chainxe2x80x9d or xe2x80x9cneutral polar amino acid side chainxe2x80x9d is used herein to refer to amino acid side chains that are not ionizable or do not carry an overall positive or negative charge. Examples of amino acids with noncharged polar or neutral polar side chains includes serine, threonine, glutamine, and the like.
The term xe2x80x9cpositively charged amino acid side chainxe2x80x9d refers to amino acid side chains that are able to carry a full or positive charge and the term xe2x80x9cnegatively charged amino acid side chainxe2x80x9d refers to amino acid side chains that are able to carry a negative charge. Examples of amino acids with positively charged side chains include arginine, histadine, lysine, and the like. Examples of amino acids with negatively charged side chains include aspartic acid and glutamic acid, and the like.
The term xe2x80x9cself-associationxe2x80x9d refers to the spontaneous association of two or more individual peptide chains or molecules irrespective of whether or not the peptide chains are identical.

Synthesis of soluble xcex2-sheet forming peptides


Write transactions with large amounts of data using a typical cache may consume over half of the available backing store bandwidth because of the way traditional caching algorithms fill lines during a write-invoked eviction. Relaxing the traditional constraint of cache coherency improves write performance by eliminating unneeded cache line fills. This technique conserves backing store bandwidth during many write operations while having negligible impact on the cache's read performance.

Computers utilize processors to access and manipulate stored data. The limiting factor on an application's performance is typically the rate at which the processor can be provided with data. This rate is referred to as the "bandwidth" between the processor and the backing store (i.e., the memory) containing the data. A backing store fashioned from a persistent storage device, such as a hard disk, can cheaply store large quantities of data. However, the bandwidth between the processor and the persistent memory may be significantly less than the rate at which the processor can actually process the data. The processor idles while it waits to receive data for processing, hindering the application's performance.
One solution to this problem uses high-bandwidth memories having significantly higher bandwidth to store data that is frequently accessed by the processor. This technique is referred to as caching. Using a high-bandwidth memory as a cache reduces the amount of time that a processor waits to receive data for processing, improving the processor's performance.
The difference in bandwidth between persistent and volatile memories is generally due to their different underlying technologies. An exemplary persistent storage device uses Winchester-style magnetic platters, while an exemplary high-speed memory uses static random-access memory (SRAM). The difference in underlying technology and resulting difference in bandwidth typically make volatile memories more expensive and smaller in capacity than persistent memories. As a result, a cache memory using volatile memory will be smaller in size than an associated backing store; otherwise, the backing store would be implemented using the cache memory technology.
The difference in capacity between the backing store and the cache memory requires that the data passing between the processor and the backing store be selectively cached in any cache memory. This requirement of selectivity has led to development of caching algorithms, i.e., methods for determining which data is to be stored in the cache. Some cache algorithms focus on improving the performance of processor reads from slower backing store memory subsystems. However, certain applications, such as saving the state of a routing table in a network router device, would benefit from improved performance in a processor's ability to write data to a backing store.
A need therefore exists for caching methods that enhance the write performance between a processor and a backing store.


A floating chamber set may include a plurality of containers coupled to a frame such that each container translates vertically within a limited vertical range independent of the other containers. Each container may be perforated to allow liquid penetration.

Trays with multiple wells can be used for simultaneously exposing multiple tissue samples to liquids. A sample may be held in a perforated container which is then mated with a well in order to expose the tissue to the liquid. In order to facilitate exposure of multiple (6, 12, 24, 96, etc.) samples simultaneously, multiple containers may be attached to one another. Enough liquid must be present in each well to treat each sample. When such containers are rigidly attached, variations on in the depth of the well or the depth of the containers may prevent the very bottom of the container from seating in the very bottom of the well. If the sample happens to come to rest at the very bottom of the well, then only a minimum of liquid is needed to fully immerse the sample. But if the sample comes to rest anywhere above the bottom of the well, additional liquid will be required to fully immerse the sample.


The present invention allows for the pack clearance of a clutch pack to be adjusted during the manufacturing process to the proper amount, even if there are variations in friction disc thickness and steel disc thickness. The present invention is an electromagnetic clutch having an adjustable pack clearance arrangement, comprising an output shaft, a pressure plate, and a clutch pack actuated by the pressure plate. The pressure plate and the clutch pack are splined to the output shaft. There is also a clutch housing splined to the clutch pack, which also receives force from the clutch pack when the pressure plate is applied. The pressure plate defines a pack clearance for the clutch pack, and the pack clearance is adjustable by a pack clearance adjusting arrangement.

Wet clutch friction systems are widely used in the field of automatic transmissions and transfer cases. Most clutches use several friction discs interleaved with several steel discs to provide torque transfer upon frictional engagement. This type of configuration is also used in braking applications. The frictional engagement is achieved through a piston disposed in a housing to enforce the frictional engagement between the friction discs and steel discs. The piston travels linearly in a cavity in a housing between an engaged (e.g. when pressure is applied) and a disengaged position (e.g. when the pressure is released and the return springs move the piston back). The amount of travel between the engaged and disengaged positions is often termed the pack clearance or "running" clearance.
When the pack is not engaged, the clearance allows for spacing between the friction disc elements interleaved with the steel disc elements. This serves two purposes, the first is to allow the friction disc elements to rotate independently from the steel disc elements, and the second is for the reduction of spin losses within the transmission. When there is not enough clearance between the separate elements, spin losses can result in drag torque. This reduces the efficiency of the transmission (or transfer case), and can also affect fuel economy. The pack clearance also has an effect on engagement time; the piston must travel the length of the pack clearance before the pack is fully engaged and full torque transfer occurs. A large pack clearance will lead to a longer engagement time, which can also affect the performance of the transmission or transfer case, depending on where the clutch is used. As transmissions and transfer cases improve in technology, reduced shift times are considered desirable.
One problem that occurs often in the manufacturing process is the variability of the thickness that can occur in the friction discs and steel discs that are used in a clutch pack. These variations in thickness in both of these elements can cause variations in running clearance once the clutch pack is assembled, affecting shift time, and spin loss characteristics. Typically, pack clearance adjustment is achieved through the use of shims. The shims take up extra space in the clutch pack so the apply piston travels a controlled distance to engage the pack.


A rectangular structure on wheels has a first and second slab. The first slab supports the patient's washing apparatus including heated water tank, an air blower and waste water tank. The second or top slab spaced apart above the first slab has an attached hinged back rest and is covered with a message pad and a disposable washing liner. The top slab is configured to have waste water flow into a drain which leads to the waste water tank.

1. Field of the Invention
The present invention relates to a patient bathing apparatus. More particularly, it refers to a movable self contained apparatus for bathing immobilized patients.
2. Description of the Prior Art
Immobile patients in hospitals and nursing homes need to be bathed at regular intervals. An apparatus for bathing such patients is described in U.S. Pat. No. 4,055,863. Although this apparatus is useful for its intended purposes, the employment of a water-tight chamber prevents nursing care personnel from attending to the patient. A patient bathing apparatus is needed which allows care personnel to directly assist in the bathing process.


There is provided an imaging apparatus including an A/D converting unit, wherein reset periods for a plurality of pixels are differentiated.

Field of the Invention
One disclosed aspect of the embodiments relates to an imaging apparatus and an imaging system including pixels each having a converting unit configured to generate a signal based on an incident electromagnetic wave and an analog/digital converting unit configured to convert a signal generated by the converting unit to a digital signal.
Description of the Related Art
An imaging apparatus has been known which includes pixels each having a converting unit configured to generate a signal based on an incident electromagnetic wave and an analog/digital converting unit (hereinafter, called an A/D converting unit) configured to convert a signal generated by the converting unit to a digital signal, as disclosed in Japanese Patent Laid-Open No. 2006-203736.

Driving method for imaging apparatus, imaging apparatus, and imaging system


A pleated blind 20 is disclosed including a head rail 22, a bottom rail 24 and an expandable and collapsible shade 28 extending between them and divided up into a plurality of pleats 30 by fold lines 32. A row of apertures 42 passes through each pleat 30 to permit passage of a supporting cord 10. The supporting cord 10 consists of a central yarn 12 and a series of equally spaced polymeric rungs 14. The rungs 14 are spaced at equal intervals along the cord 10, the spacing between the rungs 14 being substantially equal to the maximum distance between the head rail 22 and the bottom rail 24 divided by the number of pleats 30 in the shade 28. In this way, the rungs 14, which are of sufficient length to span the sides of the apertures 42, will support their respective pleats 30 and prevent the pleats from opening up too widely, thus ensuring that the pleat spacing remains substantially even.

Pleated blinds usually consist of a head rail and a bottom rail and one or more cords which are used to raise or lower the bottom rail with respect to the head rail. An expandable and collapsible pleated shade is arranged between the head rail and the bottom rail so as to expand or collapse along predetermined fold lines when the bottom rail is raised or lowered. The predetermined fold lines usually lie parallel to the head rail and bottom rail. The pleats of the shade are usually manufactured to be equal size within normal manufacturing tolerances.
During normal use of the blind, each pleat carries the cumulative weight of every pleat beneath it, other than those which are resting on the bottom rail. The greater the vertical dimension of the blind, the greater the weight that the higher pleats carry. A consequence of this is that the uniform appearance of equally spaced pleats is lost, because the load on each pleat causes the pleat to creep and open up the angle of its fold. Eventually, the apparent distance between pleats is noticeably greater at the top of the blind than it is at the bottom. The blind can be described as "sagging". For free hanging blinds installed vertically to rectangular windows, this sagging effect does little more than alter the appearance of the blind as described. However, an increasingly popular use for pleated blinds is in conservatory roofs, many of the window shapes of which are not rectangular. The problem of sagging of, for example, a triangular blind manifests itself as a progressively curving and tapering gap between the edge of the blind and the window frame. In these circumstances, the blind is no longer covering the whole of the window area and this is clearly undesirable.
The problem of blind sagging has been addressed and it is known to take remedial steps by mechanically fixing the pleats in their desired position. This is often done by supporting them from above. The simplest way of achieving this is to sew a very fine thread or monofilament from pleat to pleat, ensuring that the length of thread of monofilament between adjacent pleats is uniform. However, this method is a very slow and labour intensive one.
Another method which has been proposed involves attaching a light ribbon to the back of equally spaced pleats, pleat by pleat, by use of what is known as a "Kimble tag" and gun. Kimble tags are commonly used to attach labels to clothes. The disadvantage of this method is that the entire blind has to be spread out on a rigid corrugated former made, for example, from 90.degree. angle aluminium. This pre-spaces the pleats before the ribbon is attached. This is both space and time consuming.
A third method involves passing a cord from the head rail to the bottom rail through apertures in each of the pleats--this being done commonly to maintain the blind in the desired vertical plane--and then to provide a second cord running down the back of the shade and provided with loops at regular intervals. The cord which passes through apertures in the pleats also passes through the loops of the second cord and these loops prevent their respective pleats from sagging beyond a pre-determined position. Again, the manufacture of this type of blind is time consuming and costly in terms of labour.


A die-casting machine using an electric servo motor as a driving source for injecting/filling molten metal into a cavity of a mold through an injection sleeve. The molten metal in the injection sleeve is injected/filled into the cavity by an injection member. During the course between the stage when the molten metal has not reached a gate of the mold yet and the stage when the molten metal begins to pass the gate of the mold, the speed of the injection member is controlled to be accelerated in a smooth speed characteristic curve which does not have a broken-line characteristic. Thus, rising to a high injection speed can be attained rapidly and smoothly.

A cold chamber type disc-casting machine in which a molten metal material is injected/filled into a cavity of a mold through an injection sleeve so as to obtain a product has been known well. In the die-casting machine, a metal material (for example, an Al alloy, an Mg alloy, etc.) melted in a melting furnace is measured and scoped by ladle every one shot. The scooped molten metal (molten metal material) is supplied into the injection sleeve. The supplied molten metal is injected/filled into the cavity of the mold by the forward movement of an injection plunger.
A process of casting with a die-casting machine generally includes an injection/filling step and a pressure intensifying step following the injection/filling step. The injection/filling step has a low-speed injection step and a high-speed injection step. A higher injection speed than that in plastic injection molding is required in the high-speed injection step. Generally in the background art, a hydraulic driving source has been used as a driving source for injection/pressure intensifying. Performance of rapid rising to a high speed is required in die-casting machines. When a small-size electric servo motor is used as a driving source for injection/pressure intensifying, the accelerating performance of the small-size electric servo motor cannot satisfy the required performance. However, when a large-size and high-power electric servo motor is used, the cost increases on a large scale.
However, hydraulic die-casting machines may cause a taint damage. Recently there is a growing demand for a clean electric die-casting machine. Such an electric die-casting machine is being developed. A die-casting machine disclosed in Japanese Patent No. 3247086 (Patent Document 1) is an example of a background-art die-casting machine using an electric servo motor as a driving source for injection/pressure intensifying. In the die-casting machine according to Patent Document 1, a fly-wheel unit for accumulating rotational energy is provided. The fly-wheel unit is driven to rotate by an injection electric servo motor before the operation of injection/pressure intensifying. Thus, the rotational energy is accumulated in the fly-wheel unit, and the power from the fly-wheel unit is supplied (added) to the driving power of the injection electric servo motor at an early stage of a high-speed injection step of an injection/filling step and at an early stage of a pressure intensifying step (pressure intensifying/holding step).
FIG. 11 is a chart showing the state of the injection/filling step and the pressure intensifying step (pressure intensifying/holding step) in the die-casting machine disclosed in Patent Document 1. In FIG. 11, the abscissa designates time, and the ordinate designates speed and pressure. As shown in FIG. 11, time of adding power from the fly-wheel unit is provided at an early stage of the high-speed injection step and at an early stage of the pressure intensifying step. Thus, the time of rising to a high injection speed is shortened, and the time of rising to intensified pressure is shortened.
In the background art, as shown in FIG. 11, the injection/filling step is definitely separated into a low-speed injection step and a high-speed injection step, and a speed in a boundary M between the low-speed injection step and the high-speed injection step is set as a broken-line characteristic. The boundary M (timing of termination of the low-speed injection step) between the low-speed injection step and the high-speed injection step corresponds to the timing when degassing has been completed and the head of molten metal has just reached a gate of a mold. The speed (injection plunger speed) is designed to rise rapidly on and after this timing.
Patent Document 1: Japanese Patent No. 3247086
In the background art, as described above, the injection/filling step is definitely separated into a low-speed injection step and a high-speed injection step, and the speed in the boundary M between the low-speed injection step and the high-speed injection step is set as a broken-line characteristic. In order to shorten the time of rising to a high injection speed, the technique disclosed in Patent Document 1 uses the rotational energy accumulated in the fly-wheel unit. However, an ON-OFF controllable clutch is required to use the rotational energy accumulated in the fly-wheel unit. Thus, the transient response in rising to the high speed is slowed by the time of ON operation of the clutch (the response delay time of the clutch). In addition, first of all, there is an obvious limit in improvement of the transient response of servo control because the speed is made to rise suddenly from a constant low speed to a high speed. That is, when the electric servo motor is controlled to be accelerated in the stage where molten metal begins to be injected/filled into the cavity of the mold, there is an obvious limit in shortening the time to reach the high speed. Further, the speed in the boundary M (the timing of termination of the low-speed injection step) between the low-speed injection step and the high-speed injection step is set at a value about 0.7 m/sec or lower in the background art. A specified time is required to rise from such a speed to a high speed.
Of die-casting machines using a hydraulic driving source as a driving source for injection/pressure intensifying, as shown in FIG. 12, there has been known a machine in which constant acceleration control is applied to a low-speed injection step of an injection/filling step by use of a hydraulic servo valve having a high-speed response so that the speed in the low-speed injection step can be increased gradually. Even in the control shown in FIG. 12, the speed in a boundary N between the low-speed injection step and a high-speed injection step is set as a broken-line characteristic. In addition, the boundary N (the timing of termination of the low-speed injection step) between the low-speed injection step and the high-speed injection step is set at a value about 0.7 m/sec or lower. Even in the hydraulic die-casting machine, it cannot be denied that there may be a problem similar to the aforementioned one though there is a difference in degrees.


A cup holding device includes a storage case having a front opening; a tray for placing a container movable between a drawn position where the tray is drawn forward from the storage case and a storage position where the tray is stored in the storage case; a holding member attached to the tray for holding the container and movable between a non-usable position where the holding member is retained in the tray and a usable position where the holding member rises above the tray; and a supporting rib. The rib is disposed at a forward end of the tray for supporting a forward end of the holding member when the tray moves forward to the drawn position and the holding member moves to the usable position, and is situated in a space formed in the holding member when the holding member is at the non-usable position.

The present invention relates to a cup holder or cup holding device disposed in a compartment of an automobile or the like and suitable for holding a cup or the like.
FIG. 7 shows a conventional cup holding device disclosed in Japanese Patent No. 2794389. The cup holding device includes a case (retainer) 50 with a front opening; a tray 51 movable between a drawn position and a storage position with respect to the case 50; and a holding member 52 movable between a non-usable position overlapped with the tray 51 and stored in the case 50 and a usable position extending upwardly through a forward movement of the tray 51.
The holding member 52 holds a periphery of a container K placed on the tray 51 through a hole of a holding portion 52a at the usable position. The tray 51 includes a pair of attaching pieces 51a projecting from a bottom surface thereof, and moves with both sides thereof sliding along guiding rails disposed on both inner sides of the case 50. The holding member 52 includes a pair of supporting pieces 52b connected to the holding portion 52a, pins 53 projecting from the supporting pieces 52b, stopping surfaces 52c provided on a lower side of a base end of the supporting pieces 52b, and upper locking portions 52d provided on an upper side of the base ends of the supporting pieces 52b. The holding member 52 is rotatably assembled to the attaching pieces 51a of the tray 51 through the pins 53 and is urged upwardly by a spring member (not shown).
The holding member 52 rotates around the pins 53 and rises obliquely with the urging force when the tray 51 is drawn out from the storage position to the drawn position. In this state, the stopping surfaces 52c abut against the bottom plate of the tray 51 to restrict the excessive rotation of the holding member 52. The locking portions 52d abut against the upper plate of the case 50, so that the holding member 52 does not rotate to the non-usable position even if an improper downward load F is applied to the holding member 52. Incidentally, reference numeral 54 represents a sub-holding member, and when a container has a diameter smaller than that of the hole of the holding portion 52a, the sub-holding member pushes the outer periphery of the container to absorb wobbling.
In the cup holding device as described above, there are the following problems. First, in the device shown in FIG. 7, when the holding member 52 receives the downward load F, the locking portions 52d apply a load to the upper plate of the case 50, so that the device might be damaged. The holding member 52 rotates with respect to the tray 51 around the pins 53 as supporting points, and has the base end side shorter than the holding portion 52a side with the pin 53 as the center. Accordingly, when an article or hand advertently pushes the holding portion 52a from above, due to the action of leverage, an excessive load is applied to the corresponding case portion contacting the locking portion 52d.
Second, in general, a cup holding device preferably has a simple structure and operates smoothly. However, the holding member 52 is urged upwardly with a spring member with the pins 53 as supporting points, and it is necessary to provide the spring member with a considerably large urging force, thereby making it difficult to move smoothly. When the tray 51 moves to the storage portion, the case 50 pushes the holding member 52 to overlap with the tray 51. When the spring member has the large urging force, a large load needs to be applied to the holding member 52 to overlap with the tray 51. Accordingly, it is preferred that the spring member for urging the holding member upwards be omitted, or, at least, have a small urging force. Further, the tray 51 and the holding member 52 are fixed to the tray 51 through the pins 53, thereby restricting the design flexibility.
Third, in the structure, the holding member 52 is lifted upwardly, and the container K is inserted into the hole of the holding portion 52a with the periphery thereof held. It is preferred that the holding member 52 is lifted parallel to the tray 51 as much as possible in view of a stable holding, an appearance or the like. When the device has a structure in which the holding member is vertically moved with respect to the tray through a parallel link, it is difficult to take a countermeasure for the load F described above, and the tray becomes large.
In view of the above problems, it is an object of the invention to provide a cup holding device, wherein even if the downward load is applied to a holding member, the holding member is not improperly shifted to a non-usable position, thereby preventing damage.
Further objects and advantages of the invention will be apparent from the following description of the invention.


Techniques are disclosed for providing system manageability for computing systems operating under OS-absent conditions. In particular, techniques are disclosed for providing fully functional system management capabilities even when the primary power source for the computing system is disabled. One aspect of the invention relates to a power supply control that facilitates the realization of low power consumption integrated circuit systems. Another aspect of the invention relates to providing fully functional ASF support when operating on auxiliary power. In one embodiment, this is implemented in a local bus adapter/controller that integrates network communication, management, and support features.

1. Field of the Invention
The present invention relates to integrated circuits and, more specifically, to power management systems and methods.
2. Background of the Invention
To reduce the total cost of ownership of computing systems such as personal computers, a number of technologies have been developed to provide more cost effective system maintenance and to maximize system "up-time". For example, some of these technologies give IT administrators more visibility and control over remote systems. Traditionally, these technologies require that the "managed" system is an operational state with the Operating System (e.g., Microsoft Windows®) of the computing system loaded. Examples of technologies that require the operating system ("OS") to be loaded are Desktop Management Interface ("DMI") and Common Information Model ("CIM").
In general, however, technologies that require the OS to be loaded do not allow an administrator to have remote visibility or access to systems that have serious hardware or software problems that prevent the OS from loading or working correctly. In addition, these technologies do not allow for a system to be remotely managed while in a low power mode. For these scenarios, there is a need for a standardized low-level technology that gives administrators remote access to and control over the managed system.
Several vendors have developed proprietary technologies in this area. Intel and IBM created Alert on LAN (AoL) technology. AoL provided remote notification of local system states and various hardware or software failures in an OS absent environment. In addition, Intel and others developed the Platform Event Trap ("PET") format, to describe how alerts were formatted over the network.
As the number of these technologies increased, computing system vendors were faced with the possibility of having to support several different alerting standards. As a result, the Distributed Management Task Force ("DMTF") developed an open remote control and alerting standard: the Alert Standard Format ("ASF").
ASF is a specification that defines methods for alerting and remote system control. ASF is specifically targeted at OS-absent environments. As used herein, the term "OS-absent" refers to a computer system that is in a state including, without limitation, a no active OS state, an inoperable OS state, a low-power state, and/or a system-sleep state.
The remote control and alerting system defined by ASF includes a remote management console that communicates with one or more clients. Here, the term "client" refers to a managed computing system. Typically, the remote management console is located remotely from the computing systems and communicates with the clients via a network. An alert sending device ("ASD"), which is a component in each client, interfaces with other components in the computing system to respond to remote control requests from the remote management console. Such requests include, for example, power-up, power-down and maintenance requests. The ASD also interfaces with sensors in the client computing system. When a sensor detects an "alert event," the ASD in the client sends a corresponding alerting message to the remote management console. To this end, the ASF specification defines interfaces for sensors, alert sending devices (which may include, for example, network interface cards or Modems), remote management console software, and system firmware in order to allow system vendors (and system component vendors) to develop ASF compliant products.
In summary, the above technologies, collectively referred to as "system manageability" technologies, enable remote system access and control in both OS-present and OS-absent environments. These technologies are primarily focused on minimizing on-site maintenance; maximizing system availability and performance to the local user; maximizing remote visibility of (and access to) local systems by network administrators; and minimizing the system power consumption required to keep this remote connection intact.
While the ASF standard specifies protocols that may be used to address problems associated with "system manageability," the ASF standard falls short of addressing many issues involved in providing a robust remote control and alerting system implementation. Accordingly, there is a need for improvements in ASF implementation in the art.
In addition, there is a need for improved power management capabilities in computing systems. Conventional power supply architectures in computing systems involve generating one or more voltage levels and providing these supply voltages to integrated circuits in the computing system. Typically, several different supply voltages are required to power different components of an integrated circuit. For example, the input-output circuits in some integrated circuits are powered off of a 3.3V supply while the digital circuits are powered off of a 1.8V supply. In addition, the analog circuits may be powered off of 1.3V, 1.8V and 2.5V supplies.
In some systems, a main power supply provides one or more voltage levels and other devices such as DC-to-DC converters convert these voltage levels to other voltage levels. For example, the PCI bus in personal computers provides two primary supply voltages of 5V and 3.3V for supplying power to devices connected to the bus. In addition, the specification defines an auxiliary 3.3V supply, named Vaux power. Vaux power is designed to provide limited power to the PCI bus devices in the event the primary supply is off. Thus, in many systems, DC-to-DC converters are used to provide a 3.3V supply and a 1.8V supply by converting the 5V level to a 3.3V level and a 1.8V level, respectively. Alternatively, a DC-to-DC converter may be used to provide a 1.8V supply from the 3.3V supply.
Many conventional DC-to-DC converters consist of standalone integrated circuits that include circuitry for converting the DC voltage level and compensation circuits for ensuring that the output level remains relatively constant under varying load conditions. Two common types of DC-to-DC converters are switching regulators and linear regulators. These converters, however, may be relatively expensive and may dissipate a significant amount of power.

System and method for managing power in an ASF system


A digital radio communications receiver for predicting correctly a frame structure and assuring correct synchronization. The digital radio communications receiver for use in a digital communications system having two or more frame structures on a single channel, comprises a unique word detector module for detecting a unique word from a received bit string, a receive timing controller for timing controlling a received frame based on the unique word detection information from the unique word detector module, a frame structure determining module for determining the frame structure based on the unique word detection information from the unique word detector module and the frame structure determining guard level, and a frame structure determining guard level setting module for setting the frame structure determining guard level that is the number of consecutive detections of the frame structure in frame structure determination conditions and outputting the resulting guard level to the frame structure determining module, whereby the probability of erroneous detection of the frame structure is lowered by recognizing a change in the frame structure and by outputting the information about the new frame structure.

1. Field of the Invention
The present invention relates to a digital radio communications receiver that predicts the structure of a received frame based on the phase and intervals of sync words picked up.
2. Description of the Related Art
In digital radio communications, correctly received information is extracted by detecting a received signal to extract received bit string and picking up a frame timing in the received bit string.
Typically, the detection of the frame timing and frame synchronization are performed by detecting a bit string that exhibits an outstanding autocorrelation in a predetermined position in frames, namely, by detecting a sync word.
A sync word is also referred to as a unique word, and the unique word is abbreviated UW in the drawings and the discussion that follows.
A unique word is detected by comparing a received bit string with the unique word bit string prepared at a receiver end. An unmatched bit count between both strings equal to or smaller than a predetermined threshold (hereinafter referred to as correlation threshold) determines that a unique word is detected.
On the other hand, an unmatched bit count at the timing of the unique word exceeds the correlation threshold determines that a unique word is missed.
When a frame synchronization is established, the receiver is capable of approximately predicting the position of the unique word. When the frame synchronization is established, a gate called an aperture is set up, and the probability of erroneous detection of the unique word is kept lowered by performing the valid detection of the unique word on or in the vicinity of the position of the unique word.
The frame synchronization is established by detecting the unique word at the predetermined positions for the specified number of consecutive frames. This operation is called backward guard and the specified number of frames is called the backward guard level. As the backward guard level is increased, the erroneous frame synchronization is less likely to take place, making higher the reliability of frame synchronization, but the time required to establish the frame synchronization gets longer. Conversely, as the guard level is decreased, the time required to establish the frame synchronization gets shorter but the erroneous frame synchronization is more likely to take place.
The detection of a frame missynchronzation is performed by verifying that the unique word is consecutively missed for the specified number of frames at the position where the unique word is supposed to appear. This operation is called forward guard, and the specified number of frames is called the forward guard level. As the forward guard level is increased, the probability of frame missynchronization due to degradation of channel quality or the like is reduced, but the time required to detect the frame missynchronization, when it actually takes place, is prolonged. Conversely, as the forward guard level is decreased, the time required to detect the frame missynchronization is shortened while the probability of the determination that a missynchronization is erroneously detected is heightened even in the situation where the frame synchronization needs to be maintained.
Some digital radio communications systems change the frame structure depending on communications conditions.
For example, in the system employing a voice activation technique, frames are transmitted only when voice remains significant, and no frames are in principle transmitted when no voice is recognized. In such a case, however, to maintain frame synchronization, a short burst containing a unique word is transmitted at regular intervals. Typically, this interval is different from the frame length.
When the frame structure changes depending on communications conditions as described above, a transmitter end is required to notify of the change in the frame structure. Available as methods of notifying of frame structure changes are one in which a predetermined bit string is set up for notifying of the frame structure in a frame and another method in which a bit string (hereinafter referred to as a frame structure flag) for notifying a change, when it takes place, is inserted.
FIG. 12 is a block diagram showing the configuration of a privately known but unpublished art digital radio communications receiver which performs frame synchronization and frame structure prediction.
Referring to FIG. 12, a unique word detector module 1 detects a unique word from a received bit string, based on the timing information from an aperture control module to be described later and the correlation threshold from a correlation threshold setting module to be described later. The radiowave received by a receiving antenna 100 is fed to a down-converter 101 which outputs a signal in an intermediate frequency bandwidth. A detector 102 detects the intermediate frequency signal and then outputs the received bit string to the unique word detector module 1. The aperture control module 2 outputs the timing information that controls the timing at which the unique word detector module 1 attempts to detect the unique word. In response to the aperture width from an aperture width setting module to be described later and the received timing information from a timing control module to be described later, the aperture control module 2 generates the timing information that is output to the unique word detector module 1.
There are further shown in FIG. 12 the timing control module 3 that outputs the receive timing information of the received signal in response to the unique word detection information from the unique word detector module 1, a frame synchronization guard level setting module 4 that sets frame synchronization determination conditions, namely, the backward guard level that is the number of consecutive detections of unique word and the forward guard level that is the number of consecutively misses of unique word (both levels are hereinafter collectively referred as the guard level), and a frame synchronization determining module 5 that results in the frame synchronization information, based on the unique word detection information from the unique word detector module 1 and the guard level from the frame synchronization guard level setting module 4.
There are yet further shown in FIG. 12 an aperture width setting module 6 that sets an aperture width as a time width within which the unique word detector module 1 attempts to detect a unique word, based on the unique word detection information from the unique word detector module 1 and the frame synchronization information from the frame synchronization determining module 5, a correlation threshold setting module 7 that sets the correlation threshold of unique word detection conditions, based on the unique word detection information from the unique word detector module 1 and the frame synchronization information from the frame synchronization determining module 5, a received signal extractor module 8 that extracts the received signal from the received bit string output by the detector 102 at the timing designated by the timing control module 3, and a frame structure determining module 9 for detecting the frame structure flag of the received signal to determine whether or not the frame structure changes.
The operation of the known digital radio communications receiver thus constructed is now discussed.
The radiowave received at the receiving antenna 100 is converted into an intermediate frequency signal, which is then fed, as a received signal by the down converter 101, to the detector 102. The detector 102 demodulates the received signal and outputs the received bit string.
The unique word detector module 1 receives the received bit string, correlates the received bit string with the unique word at the timing set by the aperture control module 2, detects the unique word and determines the phase of the unique word from the number of erratic bits and their correlation threshold, and then outputs the determination results as the unique word detection information.
The timing control module 3 controls the receive timing based on the unique word detection information.
The frame synchronization determining module 5 determines the frame synchronization state using the number of consecutive detections/misses of the unique word of the unique word detection information designated by the guard level setting module 4, and outputs the determination results as the frame synchronization information.
Referring to the unique word detection information and the frame synchronization information, the aperture width setting module 6 sets and outputs the aperture width that is used at the next attempt to detect the unique word.
Referring to the unique word detection information and the frame synchronization information, the correlation threshold setting module 7 sets and outputs the correlation threshold that is used at the next attempt to detect the unique word.
To determine whether the frame structure changes, the frame structure determining module 9 detects the frame structure flag indicative of the frame structure of the received signal that is extracted by the received signal extractor module 8 from the received bit string output by the detector 102 at the timing designated by the timing control module 3.
Discussed next is how the frame structure is recognized when the known art digital radio communications receiver performs frame synchronization control.
FIG. 13 shows an example of the change in the frame structure depending on communications conditions. Part of FIG. 13 herein shows a simplified version of FIG. 2 that is presented in a paper entitled "RADIO TRANSMISSION IN THE AMERICAN MOBILE SATELLITE SYSTEM" (A COLLECTION OF TECHNICAL PAPERS, AIAA-94-0945-CP, pp 280-294, 1994).
FIG. 13 shows a unique word 17, a frame structure flag 18-a indicative of a frame structure 1 and inserted at the change from a frame structure 2 to the frame structure 1, and a frame structure flag 18-b indicative of the frame structure 2 and inserted at the change from the frame structure 1 to the frame structure 2.
In the frame structure in FIG. 13, a unit or interval of the frame structure 1 delimited by unique words is called a subframe, and four subframes make up a frame. The interval between unique words in the frame structure 2 is identical to the frame length. In FIG. 13, in other words, the frame structure 1 has a unique word on a per subframe basis, and the frame structure 2 has a unique word on a per frame basis.
FIGS. 14 and 15 show examples of the recognition of the frame structure in which when the frame structure changes, a frame structure flag notifying of it is transmitted only once. FIG. 14 shows the example of the false detection of a frame structure flag, and FIG. 15 shows the example of a miss of a frame structure flag.
In FIG. 14, the frame structure determining module 9 suffers the false detection of a frame structure flag and thus erroneous determination of frame structure. The frame structure determining module 9 thus remains unable to receive a frame structure flag and thus unable to recognize correctly the frame structure until the frame structure is changed next.
In FIG. 15, the frame structure determining module 9 misses a frame structure flag and erroneously determines the frame structure. In this case, again, the frame structure determining module 9 remains unable to recognize correctly the frame structure until the next change in frame structure.
FIG. 16 shows an example of the effect of the above faulty determinations.
In the detection failure of the frame structure flag in FIG. 16, the frame synchronization forward guard level is 2.
As shown in FIG. 16, with the miss of the frame structure flag, the receiver attempts to receive the frame structure 1 though the frame is already changed from frame structure 1 to frame structure 2. Since the unique word interval is different between the frame structure 1 and the frame structure 2, the receiver suffers a detection failure of unique word in an attempt to detect the unique word with the unique word interval of the frame structure 1. Such a state continues until the frame is changed from frame structure 2 to frame structure 1, and it is highly likely that a missynchronization would take place in the course of repeated detection failures of the unique word.
In the known digital radio communication receiver thus constructed, when the flag notifying of the change in the frame structure is transmitted only once, followed by the failed or false detection of the flag, the receiver remains unable to correctly recognize the frame structure until the frame structure changes later again. Furthermore, the faulty recognition of the frame structure may cause the frame synchronization control to malfunction, possibly leading to a missynchronization.


The present invention provides a method and system for operating a wireless communication system in which received signals from a plurality of antennas are weighted and combined with a beam forming operation to form an output signal. In an embodiment of the present invention, beamforming operations are performed with maximal ratio combining (MRC) and an interference nulling algorithm (INA). The INA receives an error signal which is 180° out of phase with a combination of the channels for individual antennas, referred to as the SUM channel. The error signal is determined by complex conjugate multiplication of the individual signals and a reference complex signal. The weight amplitude is controlled by weight normalization to provide faster convergence and prevent integrator overflow.

1. Field of the Invention
This invention relates generally to wireless communication systems. More particularly, it relates to a wireless communication system using a plurality of antenna elements with weighting and combining techniques for optimizing antenna diversity and combining gain.
2. Description of the Related Art
Recently, the market for wireless communications has enjoyed tremendous growth. Wireless technology now reaches or is capable of reaching virtually every location on the face of the earth. Hundreds of millions of people exchange information every day using pagers, cellular telephones and other wireless communication products.
With the appearance of inexpensive, high-performance products based on the IEEE 802.11a/b/g Wireless Fidelity (Wi-Fi) standard, acceptance of wireless local area networks (WLANs) for home, Small Office Home Office (SOHO) and enterprise applications has increased significantly. IEEE 802.11b/g is a standard for a wireless, radio-based system. It operates in the unlicensed 2.4 GHz band at speeds up to 11M bits/sec for IEEE 802.11b and 54 M bits/sec for IEEE 802.11g. The IEEE 802.11b/g specification sets up 11 channels within the 2.4 GHz to 2.4835 GHz frequency band which is the unlicensed band for industrial, scientific and medical (ISM) applications. IEEE 802.11a is another standard for a wireless, radio-based system in the ISM band. It operates in the unlicensed 5-GHz band at speeds up to 54 M bits/sec.
It has been found that WLANs often fall short of the expected operating range when actually deployed. For example, although a wireless Access Point (AP) is specified by a vendor as having an operating range of 300 feet, the actual operating range can vary widely depending on the operating environment.
In particular, WLAN performance can be greatly degraded by direct and multipath radio interference. Multipath occurs in wireless environments because the radio frequency (RF) signal transmitted by the subscriber is reflected from physical objects present in the environment such as buildings. As a result, it undergoes multiple reflections, refractions, diffusions and attenuations. The base station receives a sum of the distorted versions of the signal (collectively called multipath).
Similarly, in any indoor wireless system, multipath interference effects occur when the transmitted signal is reflected from objects such as walls, furniture, and other indoor objects. As a result of multipath, the signal can have multiple copies of itself, all of which arrive at the receiver at different moments in time. Thus, from the receiver's point of view, it receives multiple copies of the same signal with many different signal strengths or powers and propagation delays. The resultant combined signal can have significant fluctuation in power. This phenomenon is called fading.
There are additional elements of performance degradation in a network of 802.11b/g WLAN access points (APs). Since the 802.11b/g channel bandwidth is approximately 16 MHz, only three non-overlapping channels operating in proximity can be accommodated without interfering with one another. The channel re-use factor imposes a severe restriction on implementation of 802.11b/g based systems which requires significantly more effort in the network deployment, and increases the chances of interference and packet collision especially within an environment with a dense user cluster, such as in an office building or apartment building. It is not usual that a user can see more than 10 different APs simultaneously. Multipath interference further complicates the situation because being physically closer to an AP does not mean the signal from the AP is stronger. Signal propagates from a different path from a remote AP can have stronger power. Thus, site survey to determine the signal propagation is often required for a corporation trying to deploy multiple APs within an office complex.
Several approaches for improving the operating performance and range in a fading environment have been suggested. In one conventional approach, selection antenna diversity is used to reduce the effect of multipath fading. Multiple antennas are located in different locations or employ different polarizations. As long as the antennas have adequate separation in space or have a different polarization, the signal arriving at different antennas experiences independent fading. Each antenna can have a dedicated receiver or multiple antennas can share the same receiver. The receiver(s) checks to see which antenna has the best receiving signal quality and uses that antenna for the signal reception. The performance gain thus achieved is called diversity gain. The performance gain increases with the number of diversity antennas. The drawback of the selection diversity approach using a single shared receiver is that fast antenna switching and signal quality comparison is required. Since an 802.11(a, b, g) signal has a short signal preamble, only two diversity antennas are typically employed. This achieves a diversity gain of approximately 6 dB in a flat Rayleigh fading environment at the required frame error rate. The diversity gain decreases to 3 dB when delay spread is 50 ns and 0 dB when delay spread is 100 ns.
In another conventional approach, signal combining is used to provide improved performance in a fading environment. Signal combining techniques employ multiple spatially separated and/or orthogonally polarized antennas. The received signal is obtained by combining the signals from the multiple antennas. One technique for providing optimal signal quality is known as maximal ratio combining (MRC). To achieve the best signal quality, the received signal from each antenna is phase-shifted such that the resultant signals from all antennas are in phase. In addition, the signal from each antenna is scaled in amplitude based on the square root of its received signal-to-noise ratio.
Another known approach to achieve performance improvement is through equalization, either in the time or frequency domain. In this technique, the multipaths arriving at the receiver are delayed, phase shifted, and amplitude scaled before they are combined (equalized). Equalization typically works better when the delay spread is large (>100 ns). The performance enhancement as a result of equalization adds to the diversity gain of antennas.
In U.S. patent application Ser. No. 10/732,003, filed Dec. 10, 2003 entitled Wireless Communication System Using a Plurality of Antenna Elements with Adaptive Weighting and Combining Techniques, a closed loop operation system which can simultaneously perform signal combining using MRC and adjacent channel interference suppression using INA are proposed. The proposed approach can be unstable in some cases and unable to achieve fast convergence and integrator overflow.
Interference suppression and range enhancement approaches are most effective if the solutions fit in a PCMCIA form factor. Solutions typically are implemented with ASIC (application specific integrated circuit) to reduce the required space. A WLAN typically employs two spatially separated omni-directional antennas to have better coverage and each antenna typically requires approximately a quarter wavelength in the resonant dimension. A solution that requires more than two antenna elements needs to fit within the PCMCIA form factor so as not to limit the available combining and diversity gain.
Additional requirements for WLAN performance enhancement are low power consumption, minimal implementation cost, and high reliability. Since WLAN client devices are typically installed in battery powered notebook computers, a low power and low cost solution are criteria for the success of a commercial product. The use of digital signal processing techniques for any solution involving multiple antenna elements uses high power and has high costs. Since each antenna element requires two high-speed analog to digital converters (ADC), a solution involving four antenna elements would use eight high speed ADCs, thereby having higher cost and higher power consumption.
Alternatively, analog implementations are typically complicated by poor component tolerances and high IC process and temperature-dependent parameter variations.
It is desirable to provide an enhanced communication system to provide diversity, combining gain or interference suppression techniques which can be self-aligned and converges to the correct parameter values, independent of process, temperature, and component variations.

This patent is subject to a terminal disclaimer.


An electrical power distribution system and automatic bus transfer switch therefor, consisting of two pairs of insulated gate bipolar transistors (IGBTs) connected in series in a back-to-back circuit configuration with respective semiconductor diodes connected across the current conducting terminals thereof so as to provide a static AC switch configuration which implements a fight-through bus transfer switch wherein only one pair of switches is rendered conductive at any one time, wherein one transistor and a diode across the other transistor of the same pair conduct in each half cycle of the AC power waveform, and thus provide power to one or more load(s) from either of two AC sources, a primary AC source or an alternate AC source.

1. Field of the Invention
This invention relates to electric power distribution systems and more particularly to an electric power distribution system which can be rapidly reconfigured in real time to provide uninterrupted power to certain load(s) under variable operating conditions.
2. Description of the Related Art
Continuous availability of electric power is necessary in a variety of environments, one of which is in naval vessels such as ships in the current fleet of the U.S. Navy, and in future all electric ships. Uninterruptible power enables uninterruptible war fighting capability and enhanced survivability by providing reliable power to all loads under all conditions, even in the presence of significant battle damage or major system faults. Such an electrical distribution system employs a source of AC power which is fed to the load(s) through a combination of circuit breakers, current limiting devices and bus transfer switches.
Accordingly, it is an object of the present invention to provide an improvement in electrical power distribution systems.
It is a further object of the invention to provide an improvement in electrical distribution systems which can be rapidly reconfigured on demand to provide substantially uninterrupted power.
And it is yet another object of the invention to provide an improved electrical distribution system employing solid state technology for implementing a bus transfer switch so as to provide uninterrupted power of all loads, particularly critical loads such as computers, under adverse operating conditions.
These and other objects are achieved by an electrical power distribution system including an automatic bus transfer switch, consisting of two sets of insulated gate bipolar transistor (IGBTs) connected in series in a back-to-back circuit configuration with respective intrinsic semiconductor diodes that are internal to the device in parallel with the current conducting terminals thereof so as to provide a static AC switch configuration which implements a fight-through bus transfer switch wherein only one set of switches is turned on at any one time and thus provide power to one or more load(s) from either of a primary or an alternate AC source and wherein one transistor and a diode across the other transistor conduct in each half cycle of the AC power waveform.
Further scope of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood, however, that the detailed description and specific example, while providing the preferred embodiment of the invention, is provided by way of illustration only, thus various changes and modifications coming within the spirit and scope of the invention will become apparent to those skilled in the art from the following detailed description.

Electric power distribution system employing a fight-through switch


Methods, systems, and apparatuses for detecting a reader signal strength in a radio frequency identification (RFID) tag is described. A tag is configured to monitor an attribute of a reader transmitted signal, such as the signal strength. The tag generates an indication of the signal attribute, and transmits the indication of the signal attribute to the reader.

1. Field of the Invention
The invention relates to radio frequency identification (RFID) technology, and in particular, to using RFID tags to monitor communication signals transmitted by RFID readers.
2. Background Art
Radio frequency identification (RFID) tags are electronic devices that may be affixed to items whose presence is to be detected and/or monitored. The presence of an RFID tag, and therefore the presence of the item to which the tag is affixed, may be checked and monitored wirelessly by devices known as "readers." Readers typically have one or more antennas transmitting radio frequency signals to which tags respond. Because the reader "interrogates" RFID tags, and receives signals back from the tags in response to the interrogation, the reader is sometimes termed as "reader interrogator" or simply "interrogator."
With the maturation of RFID technology, efficient communication between tags and interrogators has become a key enabler in supply chain management, especially in manufacturing, shipping, and retail industries, as well as in building security installations, healthcare facilities, libraries, airports, warehouses etc.
In is important for reader signals to be received by tags. Various attributes of a communications environment may affect the ability of tags to receive reader signals. For example, obstacles in the environment may block, reflect, or attenuate reader signals. Reflection of signals may lead to "multi-path" issues, which can further lead to "RF nulls" in the environment.
Ideally, RFID readers transmit and receive RF energy in a straight line of sight with the RFID tags. However, in real implementations, this is rarely the case. Instead, the RF energy travels along multiple paths to the tag. These "multi-paths" are the product of the RF energy bouncing, reflecting, and/or being nulled by objects in the environment, including floors, walls, people, liquids, etc. The RFID environment can sometimes have "RF nulls" (e.g., dead zones) where the RF multi-paths substantially cancel, causing loss of the reader signal in the location of the null.
Thus, what is needed are ways to improve a quality of communications between readers and tags in an RFID communications environment to improve tag read rates.

RFID tag receive signal strength indicator


An end connector for connecting a tubular support structure having at least one optic fiber associated with a fiber optic cable, to a terminal of an associated device. A housing member is configured with a passageway from a front end to a rear end for passing the tubular support structure therethrough. A clamping portion including a flexible sleeve and compression grommet are received and supported by both the housing and a compression nut which couples to the rear end of the housing. As the compression nut is threaded onto the rear end of the housing, the compression grommet is compressed, and in turn the flexible sleeve constricts to apply clamping pressure to the tubular support structure holding the optic fibers.

This invention relates to end connectors used to connect optic fibers of a fiber optic cable to device ports, terminals or the like.
Fiber optic technology is being increasingly adapted for various applications in industries such as cable television for replacing coaxial cables. Such adaptations involve varying hybrid fiber optic systems, wherein fiber optic transport cables are linked to down-line optical repeaters or amplifiers, and to junctions where a conversion to light wave frequencies from radio frequencies for distribution to associated equipment takes place. The use of fiber optics in an industry such as cable television allows for the increases in both the reliability and number of channels of the system. The technology also allows for the expansion of basic television service to include services such as HDTV (High Definition Television), and PCN (Personal Communication Networks) so that the cable television system may compete with the telephone industry.
The cables being utilized in such systems are configured to protect and transport optic fibers, varying from a single fiber to hundreds of fibers. The cables are manufactured in a number of configurations, and most include various structural strength and support members with an outer protective dielectric plastic jacket. A variety of support members are available including corrugated metallic sheaths, plastic or glass fillers, peripherals strength members steel wires, glass filament rods or Kevlar.TM. placed in either peripheral positions or as a center support rod, or steel center support wires. Such support members are critical components given the hostile environments in which the cables are employed, i.e., placement in tunnels, fed through conduits, buried underground, or pulled-2-pole connections.
The individual optic fibers, as well as groups of fibers, are carried in small hard protective tubular support structures or "tubes" within the cable. The optic fibers are delicate and cannot be subjected to damage or stresses from bending, stretching, moisture or chemical intrusion, excessive rotational or longitudinal stresses on the cable or any other circumstance that could effect the optical transmission characteristic of the individual optic fibers. Furthermore, damage to the optic fibers may result from excessive rotational and radial stresses involved in linking either the entire cable or the individual tubes to the intended device equipment.
It is therefore an object of the present invention to provide a fiber optic end connector which supports the tubular support structures which contain one or more optic fibers in a secured position so as to resist rotational and longitudinal forces while being coupled to equipment terminals.


An electrostatic measurement apparatus for generating a modified electrical signal in proportion to an electrostatic potential present on a surface. The apparatus includes a sensor for producing a signal representative of the electrostatic potential on the surface. The apparatus also includes a high-voltage level shifter and a converter to transform the sensor signal into a low-voltage signal indicative of the surface potential. The electrostatic measurement apparatus is implemented using high-voltage and low-voltage integrated circuit technology.

The present invention is a device capable of measuring electrostatic potentials with insignificant current flow into the input of the device. Generally, such devices include a probe or sensor assembly working in conjunction with an associated voltmeter assembly which receives the signals from the probe and produces an output signal. Subsequently, the output signal may be used to drive an indicator, or to control an electrostatic process as a function of the measured electrostatic potential. Thus, the features of the present invention may be used in the printing arts and, more particularly, in an electroreprographic system to control a xerographic process. These electrostatic voltmeters, or ESVs, are particularly well suited for measuring photoreceptor surface charge, which in turn allows for the automated adjustment of machine characteristics to achieve high quality reprographic output.
Heretofore, it has been recognized that the sensing probe or electrode must be modulated, with respect to the field being measured in order to accurately measure the field. Moreover, two methods of achieving the required modulation of the electrode are known, the first requiring a stationary electrode and a vibrating element, or vane to modulate the field which reaches the electrode, as described by U.S. Pat. No. 3,921,087 to Vosteen (Issued Nov. 18, 1975), or by U.S. Pat. No. 4,149,119 to Buchheit (Issued Apr. 10, 1979). The second approach utilizes a moving electrode, affixed to the end of a vibrating element as disclosed in U.S. Pat. No. 3,852,667 to Williams et al. (Issued Dec. 3, 1974), or alternatively as disclosed in U.S. Pat. No. 5,212,451 to Werner (Issued May 18, 1993).
The ESV may also utilize an "ion probe" similar to that disclosed by Williams in U.S. Pat. No. 4,270,090 (Issued May 26, 1981) to produce a signal representative of the potential on the surface being characterized.
Moreover, numerous approaches are recognized to process the signal produced by the sensing electrode, thereby enabling the measurement of the electrostatic field potential. Some signal processing approaches are illustrated in the following disclosures which may be relevant:
U.S. Pat. No. 3,667,036 PA1 Patentee: Seachman PA1 Issued: May 30, 1972 PA1 U.S. Pat. No. 4,027,240 PA1 Patentee: Meade PA1 Issued: May 31, 1977 PA1 U.S. Pat. No. 4,061,983 PA1 Patentee: Suzuki PA1 Issued: Dec. 6, 1977 PA1 U.S. Pat. No. 4,149,119 PA1 Patentee: Buchheit PA1 Issued: April 10, 1979 PA1 U.S. Pat. No. 4,330,749 PA1 Patentee: Eda et al. PA1 Issued: May 18, 1982 PA1 U.S. Pat. 4,853,639 PA1 Patentee: Vosteen et al. PA1 Issued: Aug. 1, 1989 PA1 U.S. Pat. No. 4,797,620 PA1 Patentee: Williams PA1 Issued: Jan. 10, 1989 PA1 U.S. Pat. No. 4,804,922 PA1 Patentee: Sometani et al. PA1 Issued: Feb. 14, 1989 PA1 U.S. Pat. No. 4,868,907 PA1 Patentee: Folkins PA1 Issued: September 19, 1989 PA1 U.S. Pat. No. 4,878,017 PA1 Patentee: Williams PA1 Issued: Oct. 31, 1989 PA1 U.S. Pat. No. 4,973,910 PA1 Patentee: Wilson PA1 Issued: Nov. 27, 1990 PA1 Japanese Publ. 62-90564 PA1 Inventor: Kumada PA1 Publication Date: Apr. 25, 1987
The relevant portions of the foregoing patents may be briefly summarized as follows:
U.S. Pat. No. 3,667,036 to Seachman discloses electrometer amplifier circuits for measuring the potential of the electrostatic charge formed on an insulating surface. The circuit includes a probe assembly consisting of probe and guard electrodes. The output of the probe electrode is connected to a high impedance circuit which comprises a Metal Oxide Field Effect Transistor (MOS FET) in a source-follower configuration.
U.S. Pat. No. 4,027,240 to Meade discloses a voltmeter used in detecting an electronic voltage signal in an ordinance firing circuit, where the voltmeter is protected by a pair of back-to-back parallel-connected limiting diodes. A first limiter is used to reduce the amplitude of the detected signal, while the second limiter prevents overloading of an indicator.
U.S. Pat. No. 4,061,983 to Suzuki discloses a transistor amplifier including a bipolar transistor supplied with an input signal and a field effect transistor (FET) which is directly connected to an output electrode of the bipolar transistor to amplify the applied signal. A protective circuit senses the load impedance and activates a voltage signal which ultimately results in the lowering of the gate potential on the FET to prevent the FET from damage.
U.S. Pat. No. 4,149,119 to Buchheit teaches an electrostatic voltmeter or electrometer which includes a probe sensor for sensing electrostatic charge present on a test surface. The probe sensor is modulated using a rotating vane or shutter arrangement. The probe is also conditioned to receive both A.C. and D.C. signals which are amplified by a D.C. amplifier, where the A.C. signal from the probe is fed back to the D.C. amplifier to stabilize its output.
U.S. Pat. No. 4,330,749 to Eda et al. teaches an electrometer apparatus for measuring the electrostatic potential on the surface of a photoconductive drum. The apparatus consists of an electrode which is placed near the surface on which the electrostatic potential is to be measured. A potential proportional to the surface potential is induced in the electrode and applied to the input of an amplifier with high input impedance. The amplifier has a MOS FET input stage with a high input impedance and a low bias current.
U.S. Pat. No. 4,853,639 to Vosteen et al. discloses a non-contacting type electrometer apparatus for monitoring the electric potential of a test surface. A sensing integrator is used in conjunction with a pre-amp and a high-gain operational amplifier (opamp) to provide an improved high-frequency response.
U.S. Pat. No. 4,797,620 to Williams discloses a non-contacting electrostatic detector which eliminates the use of high-voltage circuitry in non-space dependent, high-voltage electrostatic monitoring devices. An A.C. voltage, having the same frequency as the modulator frequency, is used to produce a zero net current flow, so that the magnitude and phase of the output signal are proportional to the magnitude and polarity of the electrostatic potential monitored.
U.S. Pat. No. 4,804,922 to Sometani et al. and U.S. Pat. No. 4,868,907 to Folkins both disclose devices which proportionally convert electrostatic voltage into current.
U.S. Pat. No. 4,878,017 to Williams teaches a non-contacting electrostatic voltage follower having a response speed independent of the frequency of modulation of the capacitance or electrostatic field between a detector electrode and the measured surface. The voltage follower is capable of following both static and dynamic characteristics of an external field or potential to be measured.
U.S. Pat. No. 4,973,910 to Wilson teaches an electrostatic analyzer that incorporates a field effect transistor (FET) as a sensor used to convert electrostatic voltage into a proportional current. The sensor is described as a semiconductive device having n-p-n junctions. In operation, a zero-field reference is used to alter the base potential of the sensor, thus forming a zero-field condition. The surface potential difference is then determined as a function of the sensor base voltage, which is directly measured by a voltmeter.
The Kumada publication (JA-62-90564) illustrates a circuit for measuring surface potential, including an independent power source which provides power to an impedance converter circuit which is separated from a signal processing circuit.
The present invention includes an electrostatic voltmeter design that employs high-voltage components provided on a single integrated circuit, thereby reducing the need for discrete components in the fabrication of electrostatic voltmeters. By providing the high-voltage components on a single integrated circuit, the performance and reliability of the components are also improved. Furthermore, the high-voltage integrated circuit components may be utilized in both contacting and non-contacting electrostatic voltmeters.
In accordance with the present invention, there is provided an apparatus for generating a low voltage signal proportional to an electrostatic potential on a surface. The apparatus comprises sensing means for producing an output signal representative of the electrostatic potential on the surface; a high-voltage source adapted to produce a first potential of first polarity; high-voltage level shifting means, powered by said high-voltage source, for generating a first signal referenced to ground in response to the output signal from said sensing means; and means, connected to receive the first signal from said high-voltage level shifting means, for converting the first signal to a low voltage signal, said low voltage signal being referenced to ground potential.
In accordance with another aspect of the present invention, there is provided an apparatus for generating a low voltage electrical signal proportional to an electrostatic potential on a surface, comprising: sensing means for producing a sensor signal representative of the electrostatic potential on the surface; a high-voltage source adapted to produce a first potential having a first polarity; high-voltage level shifting means, powered by said high-voltage source, for generating a first current signal referenced to ground in response to the sensor signal; a current mirror, connected to the output of said high voltage level shifting means, for receiving the first current signal and producing a second current signal as a function of the first current signal; a second voltage source adapted to produce a second potential at a polarity opposite said first polarity, said second voltage source being adapted to drive said current mirror; and a transimpedance amplifier, connected to the output of said current mirror, for transforming the second current signal produced by said current mirror into a low voltage signal indicative of the electrostatic potential on the surface.

Electrostatic voltmeter producing a low voltage output