Entropy coding and decoding techniques are described, which may be implemented separately or in combination. For example, a video encoder uses two-layer run level coding to reduce bitrate for frequency transform coefficients in a quick and efficient manner, and a video decoder uses corresponding two-layer run level decoding. This two-layer coding/decoding can be generalized to more than two layers of run level coding/decoding. The video encoder and decoder exploit common patterns in run level information to reduce code table size and create opportunities for early termination of decoding. Using zoned Huffman code tables helps limit overall table size while still providing a level of adaptivity in encoding and decoding. Using embedded Huffman code tables allows the encoder and decoder to reuse codes for 8×8, 8×4, 4×8, and 4×4 blocks.

With the introduction of digital video disks and video delivery over the Internet, digital video has become commonplace. Engineers use a variety of techniques to process digital video efficiently while still maintaining the quality of the digital video. To understand these techniques, it helps to understand how video information is represented and processed in a computer.
I. Representation of Video Information in a Computer
A computer processes video information as a series of numbers representing that information. A single number typically represents an intensity value for one picture element ["pixel"] of a picture. Several factors affect the quality of the video information, including sample depth, resolution, and frame rate.
Sample depth (or precision) indicates the range of numbers used to represent a sample. When more values are possible for the sample, quality is higher because the number can capture more subtle variations in intensity. Video with higher resolution tends to look crisper than other video, and video with higher frame rate tends to look smoother than other video. For all of these factors, the tradeoff for high quality is the cost of storing and transmitting the information, as Table 1 shows.
TABLE 1Bitrates for different quality levels of raw videoDescriptionBits Per PixelResolutionFrame RateBitrateLow-resolu-8 (value 0-160 × 1207.5 1.2 Mbit/stion, gray scale255)pixelsvideo monitor-ingInternet stream-24 (value 0-240 × 1761515.2 Mbit/sing 16,777,215)pixelsVideoconfer-24 (value 0-352 × 2883073 Mbit/sencing16,777,215)pixels
Table 1: Bitrates for Different Quality Levels of Raw Video
Very high quality formats such as those used for HDTV use even more bitrate. Despite the high bitrate, companies and consumers increasingly depend on computers to create, distribute, and play back high quality content. For this reason, engineers use compression (also called coding or encoding) to reduce the bitrate of digital video. Compression decreases the cost of storing and transmitting the information by converting the information into a lower bitrate form. Decompression (also called decoding) reconstructs a version of the original information from the compressed form. Two categories of compression are lossless compression and lossy compression.
Lossless compression reduces the bitrate of information by removing redundancy from the information. For example, a series of ten red pixels is represented as a code for "red" and the number ten in compression, and the series is perfectly reconstructed in decompression. Lossless compression techniques reduce bitrate at no cost to quality, but can only reduce bitrate up to a certain point. Decreases in bitrate are limited by the complexity of the video. Entropy coding is another term for lossless compression.
In contrast, with lossy compression, the quality of the video suffers but decreases in bitrate are more dramatic. For example, a series of ten pixels, each a slightly different shade of red, is approximated as ten pixels with the same "red" color. Lossy compression techniques can reduce bitrate more by removing more quality, but the lost quality cannot be restored. Lossy compression is typically used in conjunction with lossless compression—the lossy compression reduces the complexity and quality of the video, which enables greater bitrate reduction in subsequent lossless compression. For example, the series of ten pixels, each a slightly different shade of red, is represented as a code for "red" and the number 10 in compression. In decompression, the original series is reconstructed as ten pixels with the same "red" color.
II. Entropy Encoding and Decoding
Entropy encoding and decoding have been an active area of research for over 50 years. A variety of entropy encoding and decoding techniques have been developed, including run length coding/decoding, Huffman coding/decoding, and arithmetic coding/decoding. This section surveys various entropy encoding and decoding techniques.
A. Run Length and Run Level Encoding/Decoding
Run length encoding is a simple compression technique used for camera video, images, and other types of content. In general, run length encoding replaces a series (i.e., run) of consecutive symbols having the same value with the value and the length of the series. For example, the sequence 3 3 0 0 0 1 0 0 0 0 is represented as value 3, length 2, value 0, length 3, value 1, length 1, and value 0, length 4. Run length encoding is particularly effective for sequences having bursts of the same values. In run length decoding, the sequence is reconstructed from the run values and run lengths. Numerous variations of run length encoding/decoding have been developed. For additional information about run length encoding/decoding and some of its variations, see, e.g., Bell et al., Text Compression, Prentice Hall PTR, pages 105-107, 1990; Gibson et al., Digital Compression for Multimedia, Morgan Kaufmann, pages 17-62, 1998; U.S. Pat. No. 6,304,928 to Mairs et al.; U.S. Pat. No. 5,883,633 to Gill et al; and U.S. Pat. No. 6,233,017 to Chaddha.
Run level encoding is similar to run length encoding in that runs of consecutive symbols of one value (typically, the predominant value) are replaced with lengths. Unlike run length coding, however, other values are not represented with lengths. Instead, each run level pair represents a run of predominant values and a single non-predominant value. For example, the sequence 3 3 0 0 0 1 0 0 0 0 0 0 0 0 0 1 is represented as length 0, level 3, length 0, level 3, length 3, level 1, length 9, level 1. Run level encoding is particularly effective for sequences in which a single value predominates, with interspersed less common values.
B. Huffman Coding and Decoding Huffman coding is another well-known compression technique used for camera video, images, and other types of content. In general, a Huffman code table associates variable-length Huffman codes with unique symbol values (or unique combinations of symbol values). Shorter codes are assigned to more probable values, and longer codes are assigned to less probable values. For example, suppose the data is a series of 8-bit samples, where 50% of the samples have a value of zero, 25% of the samples have a value of one, and the remaining samples have values in the range of 2 to 255. Rather than represent each sample with 8 bits, the encoder uses a 1-bit code "0" for the value 0, a 2-bit code "10" for the value 1, and longer codes starting with "11" for other values. The least likely values may take more than 8 bits to represent, but the average bitrate is reduced due to the efficient coding of the most common values.
To encode a symbol, the Huffman encoder replaces the symbol value with the variable-length Huffman code associated with the symbol value in the Huffman code table. To decode, the Huffman decoder replaces the Huffman code with the symbol value associated with the Huffman code.
In scalar Huffman coding, a Huffman code table associates a single Huffman code with one value. Scalar Huffman coding is relatively simple to implement, but is inefficient when a single value predominates. For example, if 70% of samples have values of 0, the ideal Huffman code would be less than 1 bit long, but the shortest possible scalar Huffman code is 1 bit long.
In vector Huffman coding, a Huffman code table associates a single Huffman code with a combination or set of values. Vector Huffman coding can lead to better bitrate reduction than scalar Huffman encoding (e.g., by allowing the encoder to exploit symbol probabilities fractionally in binary Huffman codes). On the other hand, the codebook for vector Huffman encoding can be extremely large when single codes represent large groups of symbols or symbols have a large ranges of potential values (due to the large number of potential combinations). For example, if the alphabet size is 256 (for values 0 to 255 per symbol) and the number of symbols per set to be encoded is 4, the number of potential combinations is 2564=4,294,967,296. This consumes memory and processing resources in computing the codebook codes and performing look up operations in coding and decoding.
In static Huffman coding, probabilities are set based upon probabilities expected for a certain kind of content. Alternatively, in adaptive Huffman coding, probabilities are computed for information just encoded or information to be encoded, in which case the Huffman codes adapt to changing probabilities for symbol values. Compared to static Huffman coding, adaptive Huffman coding usually reduces bitrate by incorporating more accurate probabilities, but the encoder and decoder must perform extra processing to track probabilities and maintain consistent code table states.
The results of run length encoding and run level encoding (e.g., levels and runs) can be Huffman encoded to further reduce bitrate. For example, the most common level is represented with a short Huffman code, and less common levels are represented with longer Huffman codes. Run lengths are represented with different Huffman codes. One problem with separate encoding of levels and lengths is that the most common level (e.g., 1 for run level encoding) and length (e.g., 0 for run level encoding) typically have probability>50%, which makes scalar Huffman coding inefficient. To address this concern, a single Huffman code may jointly represent the pair of a particular level value and a particular length value. With this system, the most likely level/length pair typically has a probability<50%. On the other hand, the Huffman code table needed to represent the various possible level/length pairs is very large.
Numerous variations of Huffman coding/decoding have been developed. For additional information about Huffman coding/decoding and some of its variations, see, e.g., Bell et al., Text Compression, Prentice Hall PTR, pages 105-107, 1990; Gibson et al., Digital Compression for Multimedia, Morgan Kaufmann, pages 17-62, 1998. U.S. Pat. No. 6,223,162 to Chen et al. describes multi-level run length coding of audio, U.S. Pat. No. 6,377,930 to Chen et al. describes variable-to-variable length encoding of audio, and U.S. Pat. No. 6,300,888 to Chen et al. describes entropy code mode switching for frequency domain audio coding.
C. Arithmetic Coding and Decoding
Arithmetic coding is another compression technique used for camera video, images, and other types of content. Like vector Huffman coding, arithmetic coding is often used in applications where the optimal number of bits to encode a given input symbol is a fractional number of bits, or in cases where a correlation between input symbols exists.
Arithmetic coding generally involves representing an input sequence as a single number within a given range. Typically, the number is a fractional number between 0 and 1. Symbols in the input sequence are associated with ranges occupying portions of the space between 0 and 1. The ranges are calculated based on the probability of the particular symbols occurring in the input sequence, and the fractional number used to represent the input sequence is constructed with reference to the ranges. Therefore, probability distributions for input symbols are important in arithmetic coding schemes. In fact, it is the preparation and updating of these probability distributions that makes arithmetic encoding and decoding undesirable in many contexts. The encoder and decoder must maintain consistent probability distribution states for correct performance, which can be burdensome depending on the number of different symbols and distributions tracked and the complexity of the tracking.
In context-based arithmetic coding, different probability distributions for the input symbols are further associated with different contexts. A context is a state that is reproducible by the encoder and decoder, typically based on previously decoded information, which provides guidance as to the probability distribution of an element in subsequent encoding or decoding. The probability distribution used to encode the input sequence changes when the context changes. The context can be calculated based upon different factors that are expected to affect the probability of a particular input symbol appearing in an input sequence. While context-based arithmetic coding can further improve the efficiency of arithmetic coding, the cost is additional computational overhead for maintaining and updating more states. For additional information about arithmetic coding/decoding and some of its variations, see Nelson, The Data Compression Book, "Huffman One Better: Arithmetic Coding," Chapter 5, pp. 123-65 (1992).
III. Implementations of Entropy Encoding and Decoding for Video
Numerous international standards specify different aspects of video encoders, decoders, and/or formats for compressed information. These standards include the H.261, MPEG-1, H.262, H.263, MPEG-4, and H.264/AVC standards. While the details of these standards vary, each uses a combination of lossy and lossless compression as well as a block-based frequency transform. With the transform, a block of pixels or other spatial domain information is converted to a block of frequency transform coefficients, which are a more efficient representation of the information. The frequency transform coefficients are then lossy encoded, zigzag scanned into a one-dimensional sequence, and losslessly encoded. The lossless compression of frequency transform coefficients typically uses some combination of run level encoding, Huffman coding, and/or arithmetic coding, but some other entropy coding techniques are specified as well. For additional details about the standards and, in particular, the myriad forms of entropy coding and decoding used in the standards, see the standards documents themselves.
The H.264 standard (sometimes called the AVC, JVT, or MPEG-4, layer 10 standard) defines two context-adaptive entropy coding methods, based on Huffman-like variable length coding and arithmetic coding, respectively. The variable length coding method is simple and not particularly resource intensive, but is also not very good in terms of compression efficiency. On the other hand, the arithmetic coding method is good in terms of compression efficiency, but is resource intensive and slow due to the state tracking that the encoder and decoder must perform.
Aside from the international standards listed above, numerous companies have produced video encoders and decoders. Microsoft Corporation has produced several versions of Windows Media Video ["WMV"]. The various versions of WMV also use different combinations of lossy and lossless compression. In WMV7, the encoder and decoder use run/level/last code tables, in which an entropy code jointly represents a run of zero-value coefficients, a non-zero level, and whether the coefficient is the last in the block. WMV7 also includes escape coding for values outside of the run/level/last tables. In WMV8 and some versions of WMV9, the encoder and decoder use variants of run/level/last coding for frequency transform coefficients, with table selection based on contextual information, and also use other entropy encoding and decoding. U.S. Patent Application Publication Nos. 2003-0138150-A1 and 2003-0156648-A1 include description of entropy encoding and decoding in WMV8.
Whatever the advantages of prior techniques and systems for lossless compression, they do not have the advantages of the present invention.

Multi-layer run level encoding and decoding


A vector processing unit includes data buffers between a storage and a vector processor. Each of the data buffers is divided into four virtual buffers. Each virtual buffer can store 16 words of data, each word having 8 bytes. Accordingly, one load data buffer can store four 8-byte vector data when the vector length is 16, and one 8-byte vector data when the vector length is 64. By compressing two 4-byte vector data into one 8-byte vector data, it is possible to store four 4-byte vector data when the vector length is 32, and 4-byte vector data when the vector length is 128.

1. Field of the Invention
The present invention relates to a vector processing unit, and, more particularly, to a vector processing unit having a data buffer between a storage and a vector processor.
2. Description of the Prior Art
In a storage shared vector processing unit, a physical distance to the storage tends to be longer as the system becomes larger in its size in view of mounting. Therefore, storage access takes much time.
The vector processing unit attains high speed arithmetic processing by continuous arithmetic processing of a large amount of data simultaneously. That is, after a group of operands is loaded from the storage to a vector register, arithmetic processing is performed by supplying the arithmetic operand to a processor from the vector register. Then, the result is stored again in the vector register the content of which is in turn stored in the storage.
Referring to FIG. 10, there is shown an example of operation in a conventional vector processing unit where vector processing is performed by transferring data between the storage and the vector register without providing any buffer. In the example, the vector processing is performed by using data from the storage with two vector load instructions VLD, and then the result of processing is written in the storage with a vector store instruction VST. Therefore, there arises idle time because of storage access. As the idle time for storage access becomes longer, idle time in the processing unit also becomes longer so that the usage efficiency of the processor is being deteriorated.
In addition, since a plurality of vector processors is provided in a the vector processing unit, there is possibility of contention in storage access in each vector processor. Therefore, it is not necessarily guaranteed that data is returned at the minimum access time so that the idle time tends to occur more often.
In order to solve this problem, the conventional vector processing unit provides a buffer between the vector register and the storage for separating the storage access from the vector processing. This improves the vector processing unit by allowing it to load data in advance so that subsequent vector processing can be continuously performed after storing the data whether or not the storage access is performed.
Referring to FIG. 11, the conventional vector processing unit 1800 comprises a vector processor 1700 having a crossbar 1710, vector registers 1720, 1721, and a processor 1730; load data buffers 1100 with a load data buffer storing circuit 1200, and a load data buffer read circuit 1300 for storing vector data to be sent to the vector processor 1700; and store data buffers 1400 with a store data buffer store circuit 1500, and a store data buffer read circuit 1600 for storing the result of processing by the vector processor 1700.
Then, the number of words per each of the load data buffers 1110 and 1120 is designed for the maximum number of elements by a vector instruction. In addition, although the number of load data buffers is two of buffers 1110 and 1120 here, it is designed by estimating the number of load instructions for which data is not returned although the instruction is issued.
Furthermore, the number of words per each of the store data buffers 1410 and 1420 is also designed for the maximum number of elements by a vector instruction. Then, the number is designed by estimating the number of store instructions which may be executed from issuance of a store instruction to storing in a storage 1900.
Referring to FIGS. 12 (A) and 12 (B), if vector length in FIG. 12 (A) is eight, the number of vector load instructions VLD is four, which can be started for issuance until the vector processing can be executed. In addition, if the vector length in FIG. 12 (B) is four, the number of vector load instructions VLD is seven, which can be started for issuance until the vector processing can be executed. Therefore, although, if the vector length is eight, four load data buffers may be sufficient, seven load data buffers are required if the load vector length is four.
Next, description is made on the operation of instructions and the result of processing by using an example of an instruction sequence. Here, for the purpose of description, it is assumed that the number of load data buffers and store data buffers is two, respectively, each has a capacity of 8 bytes.times.64 words, there are an 8-byte load instruction VLD, an upper 4-byte load instruction VLDU, a lower 4-byte load instruction VLDL, an 8-byte store instruction VST, an upper 4-byte store instruction VSTU, a lower 4-byte store instruction VSTL, a fixed point addition VADD, and a floating point addition VFAD, and the maximum number of vector elements which these instruction can have is 64. Furthermore, the vector registers are refered to as V0 and V1.
Here, it is assumed that the instruction sequence shown in FIG. 9 is executed by assuming that the vector length is 16.
Referring to FIG. 13, when the instruction sequence is processed in the conventional vector processing unit by using two load data buffers, vector load instructions of instructions (1) and (2) are first assigned with the load data buffers 1110 and 1120, respectively. Then, the load data buffers 1110 and 1120 are also used for vector load instructions of instructions (5) and (6). Similarly, vector store instructions of instructions (4) and (8) are assigned with the store data buffers 1410 and 1420, respectively.
In this case, because there are only two load data buffers, the instruction (5) cannot be issued until the load data buffer V0, which is used by the instruction (1), is released. Thus, delay time as shown in FIG. 13 occurs.
Referring to FIG. 14, since the load data buffers 1110, 1120 and the store data buffers 1410, 1420 are configured in a fixed size, there is a possibility that a number of unused regions is caused in the load data buffers 1110, 1120, and the store data buffers 1410, 1420 if the vector is short.
As an example of such a conventional vector processing unit, European Patent Application No. 445,802-A2 describes a vector processing unit with a store buffer.
As described above, because the conventional vector processing unit has the fixed number and capacity of data buffers, it has a disadvantage that the usage efficiency is degraded depending on a program configuration. That is, when the vector length is long, there is little impact on the performance even if the number of data buffers is relatively small. However, if the vector length is short, the vector processor may not be efficiently utilized without providing a large number of data buffers. On the other hand, because vector length depends on a program, a relatively large number of data buffers should be provided for a case where the vector length is short to fully extract the performance of the conventional vector processing unit regardless of the vector length, which causes a problem that the amount of hardware is increased.

Vector processing unit with reconfigurable data buffer


The invention relates to the design and synthesis of novel anabaseine-based compounds, which are useful in treating or preventing a wide variety of conditions, including nervous system diseases or disorders, such as, schizophrenia, Alzheimer's disease, Parkinson's disease, drug dependence, and substance addiction, and compositions, kits, and methods thereof. The invention also provides novel anabaseine-based compounds, compositions, kits, and methods thereof for treating or preventing non-nerve system diseases or disorders (such as, inflammation and cancer) in a subject identified in need thereof. Certain enantiomeric compounds of the invention exhibited enhanced selectivity toward α7 nAChRs relative to alpha4beta2 nAChRs. Other enantiomeric compounds of the invention exhibited enhanced selectivity for alpha4beta2 nAChRs relative to α7 nAChRs.

Acetylcholine receptors can be divided into muscarinic (mAChR) and nicotinic (nAChR) subtypes in the mammalian central nervous system (CNS). These subtypes are distinguished based on their ability to be stimulated by either the mushroom toxin muscarine or the plant alkaloid nicotine. Nicotinic receptors are important in cholinergic transmission in autonomic ganglia, striated muscles, the neuromuscular junction, and in brain and spinal synapses.
Several types of nicotinic acetylcholine receptors (nAChRs) are known to play a role in central nervous system activity, such as, they are involved in cognition, mood and neuroprotection. The various types of known nicotinic ligands appear to have different combinations of effects on nicotine-modulated functions, depending on the subtypes of nAChRs affected, some affecting all receptors, others having more selective actions. Within the nervous system, the non-neuronal cells include microglia and astrocytes; outside the nervous system non-neuronal cells expressing alpha7 receptors include macrophages, vascular endothelium and pulmonary epithelial cells. Some nAChRs are also expressed in non-neuronal or muscle cells.
All known mammalian nAChRs are cation selective ligand-gated ion channels that form pentameric structures in the plasma membrane. Each subunit of the pentamer contains four transmembrane domains. There are at least seventeen different nAChR subunit genes, including five found in striated muscle (α1, β1, γ, δ, ε) and twelve neuronal nAChR subunits (α2-10, β2-4). These channels can be composed of a number of different combinations of subunits.
Neuronal nAChR deficits have been implicated in several diseases including AD and schizophrenia. Until recently, the study of neurodegenerative diseases focused on the muscarinic type neuronal acetylcholine receptor (mAChR) because of its abundance in the brain when compared to the population of neuronal nicotinic receptors (nAChRs). However, the discovery of a greater relative loss of nicotinic receptors than of muscarinic receptors in the Alzheimer's brain, as well as evidence that nicotinic agonists enhance cognition has spurred interest in nAChRs. This is supported by the observation of enhanced attentiveness and rapid information processing in humans receiving nicotine or 3-(2,4-dimethoxy benzylidene)-anabaseine (DMXBA) (GTS-21) treatment. The two major brain nAChRs α4β2 ("alpha4beta2") and α7 ("alpha7") are important for cognitive processes such as attention, learning and memory. Since brain alpha7 nicotinic receptors are spared relative to the α4β2 nAChRs in Alzheimer's disease and also possess exceptionally high calcium ion permeability, they are considered a particularly promising therapeutic target for treatment of Alzheimer's disease. In addition to their direct involvement in synaptic transmission, certain nicotinic receptor subtypes, particularly alpha7, because of their very high calcium permeability also stimulate calcium-dependent intracellular signal transduction processes that are neuroprotective by maintaining neuronal integrity in the presence of stressful states such as ischemia or mechanical trauma.
Central cholinergic neurons have been implicated in a number of neurodegenerative conditions including, Alzheimer's disease (AD) and schizophrenia. Alzheimer's disease (AD) affects an estimated 15 million people worldwide and accounts for approximately 50-60% of the overall cases of dementia for people over the age of 65. The characteristic pathology of AD includes extracellular β-amyloid plaques, intracellular neurofibrillary tangles, loss of neuronal synapes and pyramidal cells. The cholinergic dysfunction in AD is represented by a reduction in the activity of the ACh-synthesizing enzyme cholineactyltransferase (ChAT) and a loss in functional nAChRs. The cause(s) of this loss in cholinergic function is not yet known.
In schizophrenia, there is a disruption in the normal brain neuronal circuits that are responsible for filtering out responses to repetitive stimuli. This malfunction causes an overload of stimuli, which may lead to misperceptions of environmental stimuli in the form of delusions and hallucinations or withdrawal from environmental stimuli, causing schizoid behavior.
Small molecule compounds, for example, certain 3-arylidene-anabaseines, have been prepared (see, e.g., WO 2004/019943) for potential use in treating neurodegenerative diseases, and particularly with the hope that some compounds would bind to nicotinic α7 receptors. While many of the arylidene-anabaseines do selectively activate α7 receptors, these compounds also bind to other nicotinic receptors. For example, these arylidene-anabaseines also have antagonistic effects on brain α4β2 subtype nicotinic receptors, which also participate in cognitive processes, and to a lesser extent other nicotinic receptor subtypes.
The importance of developing highly selective α7 nicotinic receptor agonists has increased as the role of these receptors in degenerative disease becomes clearer. There is a particular need for new compounds useful in treating cognitive dysfunctions (such as AD and schizophrenia) where degenerative processes drastically interfere with cognitive and physiological processes.
Therefore, there is a need for development of selective α7 agonists that do not bind to and interfere with the normal functioning of other nAChRs. Such agonists would produce fewer side effects arising from interaction with other nicotinic receptor subtypes.

Nicotine receptor targeted compounds and compositions

University of Florida Research Foundation, Inc.


A medical support apparatus comprises an adjustable davit arm hingedly coupled near the top end of a mast extending vertically from a floor base or other support. The davit arm has an extension beam telescopically cooperating with a cylindrical cavity within the davit arm and a fixing means to secure the beam in longitudinal position. A cable attached to the davit arm and to the end of the beam with pulleys has on one end a gripping means for attaching to a medical apparatus, and on the other end a counterweight for counterbalancing the weight of the medical apparatus.

1. Field of the Invention
This invention relates to improvements to medical support devices and particularly to devices adapted to support the weight of a medical apparatus attached to a patient or to support a portion of the patient's body. More particularly, this invention relates to a support for counterbalancing a tracheotomy tube and thereby mitigating discomfort caused to a patient by of its weight or restrictiveness.
2. Description of Related Art
Medical patients in a weakened state from surgery, disease or other medical conditions often are sensitive to the weight of any medical apparatus necessarily attached to them as part of their treatment. The weight of tracheal interfaces, tubes from treatment equipment and the like, for example, can cause considerable discomfort to such patients, whereas healthy persons would not even notice the weight. Often left unsupported and lying across a bedridden patient's chest, the tube can slide off the bed or otherwise shift around and cause irritation at the patient's throat. If taped or clipped to the bed to prevent it from sliding off, the tube restricts the patient's movements dramatically. A need exists for a device which supports a tracheal interface tube without unnecessarily restricting a patient's movements and which mitigates discomfort of the tracheal interface caused by the weight of the tube.
Non-bedridden but nonetheless invalid patients may be able to sit up in a chair, eat on their own, watch television and move about their home or hospital room as long as their movements are not restricted by treatment equipment. Tracheotomy patients who achieve some degree of mobility as a rule find themselves tethered to treatment equipment. Discomfort from the weight and agitation from movement of tracheal interface tubes severely restrict even the simplest movements such as turning one's head, swallowing or talking. Relocation from one resting place to another requires moving the treatment equipment and consequently greater agitation and discomfort from the tubes. Even when beds are equipped with support devices, they usually cannot be removed and relocated conveniently to an upright chair, so the tube simply must be laid across the patient's shoulder or otherwise left vulnerable to falling. A need therefore exists for a trachea tube support device readily movable with an ambulatory patient.
Particularly weak patients, such as those with degenerative muscular conditions, find it difficult or impossible simply to lift their arms to feed themselves. The effort of lifting the weight of their arms combined with the effort of gripping a fork can be more than some can manage. Many times, such patients can grip utensils sufficiently to help themselves and can use them as long as a nurse or attendant helps by lifting the patient's arm. The morale boost from successfully negotiating even such simple tasks can be a significant factor in recovery. Yet, many patients cannot afford the luxury of, and others would not want, the constant attention of an attendant. A need exists therefore for a cost effective apparatus for supporting the weight of a patient's arm to assist in such activities.
Numerous support devices provide support for medical apparatus, but none offer the utility of the present invention. For example, Doyle, U.S. Pat. No. 4,591,121, provides a gantry attached to a bedstead to support multiple fluid containers for intravenous tubes above the patient's pillow. Doyle necessarily requires, however, that the patient be confined to the bed. Hawk, U.S. Pat. No. 4,727,872, provides another gantry suspended above a supine patient with an endotracheal device rigidly gripping the crossmember. Hawk offers no freedom of movement, either.


An article of footwear is provided, particularly a soccer shoe, having one or more sensors mounted in the shoe upper which, when impacted by a ball, are effective to send a signal to a controller representative of the magnitude of the force with which the ball was struck by the shoe. A liquid crystal display, mounted within a housing which also carries the controller, provides a visual indication of the force of the ball strike which can be readily observed by the wearer of the shoe.

Articles of footwear have been provided with a wide variety of functional and aesthetic features ranging from decorative arrays of light sources such as light emitting diodes (LEDs) to air bladders located within the outsole of the shoe for enhanced comfort when performing activities such as running. Many improvements to footwear have been sports-specific and intended to assist the wearer with one or more aspects of his or her performance, or to assist in training for a particular sport.
Footwear intended for playing soccer is no exception. A number of designs to assist players in their training exercises have been proposed. For example, U.S. Pat. No. 4,204,346 to Fugers, U.S. Pat. No. 5,216,827 to Cohen and U.S. Pat. No. 5,897,446 to Wiseman et al disclose soccer shoes with different colored areas on the upper to aid the wearer in identifying and focusing on the desired location where he or she strikes the ball with the foot. U.S. Pat. No. 4,711,043 to Johnson et al teaches an attachment for a shoe which emits sound when the ball strikes it at desired location, but is silent if the ball strike is elsewhere.
Pressure sensors have also been incorporated into soccer shoes and other footwear such as disclosed in U.S. Pat. No. 6,808,462 to Snyder et al. In this invention, one or more pressure sensors are mounted on the upper of the shoe at locations where it is desired to make contact with the ball. When one of these sensors is activated as a result of a ball strike, an electrical signal is sent to a microprocessor which then causes a loudspeaker to produce a particular sound, e.g. "Way to Go" or the like.


An optical absorption spectrometry system includes first and second light sources, a dichroic beam combiner and a wavelength selective module. The first light source emits first light having first wavelengths within a first wavelength range, and the second light source emits second light having second wavelengths within a second wavelength range different from the first wavelength range. The dichroic beam combiner includes a predetermined first reflectance/transmission transition region, the dichroic beam combiner being configured to transmit a first portion of the first light and to reflect a second portion of the second light to provide combined light. The wavelength selective module is configured to disperse the combined light received at an entrance aperture, to select a sample wavelength range of the dispersed light as sample light, and to output the sample light having the selected sample wavelength range from an exit aperture for illuminating a sample.

Generally, conventional optical absorption spectrometers use one light source, which may be selected from among multiple possible light sources and incorporated into the optical absorption spectrometry system to perform spectrochemical analysis of a particular sample. The type and characteristics of the light source selected depend on the specific wavelength and/or wavelength range of light to be used for the spectrochemical analysis.
When different experiments require different light wavelengths and/or light wavelength ranges, the light source must be physically replaced with another light source having the appropriate characteristics. This process is generally inefficient and time consuming, increasing complexity and cost, while reducing reliability. Also, when an experiment requires light wavelengths from two or more different light sources, the light source must be changed during the measurement process, typically resulting in noncontiguous results, particularly at transitions between wavelength ranges of the respective light sources.

Optical absorption spectrometry system including dichroic beam combiner and splitter


In one possible implementation, a method is provided for determining contactor health including measuring a differential voltage between a first utility line voltage and a second utility line voltage on a primary side of a contactor and on a secondary side of the contactor. The measuring is performed with both an unloaded current and with a load current. The unloaded and loaded measurements are performed at the primary side and the secondary side, and are made with the contactor closed. It includes determining a difference between a secondary unloaded voltage and a secondary loaded voltage and subtracting a difference between a primary unloaded voltage and a primary loaded voltage to provide a contactor voltage drop. The contactor resistance is determined by dividing the contactor voltage drop by the loaded current.

Electric vehicles may now be charged with utility power and with high current. As a result, even a small resistance in the line can be inefficient and can generate significant heat, which could pose a serious hazard. What is needed is a means to monitor the charging circuit to reduce the potential of overheating, and improve the efficiency of the circuit.

Contactor health monitor circuit and method


A riding hydraulically driven aerator is disclosed herein. The aerator includes a frame, an engine, one or more hydraulic pumps, one or more drive wheels, and one or more tine assemblies. The one or more tine assemblies may be driven by one or more hydraulic tine motors. The one or more hydraulic tine motors may be directly coupled to the one or more tine assemblies. In various embodiments, the one or more drive wheels are driven by one or more hydraulic wheel motors. The one or more hydraulic tine motors and the one or more hydraulic wheel motors may be driven in series by the one or more hydraulic pumps.

Aerating turf has grown from the golf course industry to a popular service provided to residential lawns because aerating relieves soil compaction and provides better air and water exchange with the turf root system. Relieving soil compaction and strengthening the root system decreases the need for fertilization and irrigation.
Aerating turf has grown from the golf course industry to a popular service provided to residential lawns because aerating relieves soil compaction and provides better air and water exchange with the turf root system. Relieving soil compaction and strengthening the root system decreases the need for fertilization and irrigation.
Due to the popularity of aerating residential lawns, small and more compact aerators have been developed from the original golf course aerators. The majority of home aerators are small walk-behind models and used in homeowner rental applications. Commercial contractors who provide an aeration service have been switching over to newer riding aerators.
These new riding aerators allow the operator to stand on a platform on the back of the machine. The machine normally has powered rear wheels that are used for transporting, turning, and aerating. The aerator tines on these machines are also typically driven for better traction and aerating performance. These tines can be raised and lowered by the operator allowing the machine to stop aerating and quickly lower them to start aerating again. Because the tines are driven on these machines, the aerator is able to utilize the weight of the machine and of the operator to increase the depth you can aerate hard soil. Only when the tines are driven are they able to utilize the full weight of the machine and operator to aerate and turn effectively.
These riding aerators utilize multiple chains, sprockets, drive shafts, and bearings which all require extensive maintenance and break down frequently. The maintenance required on these riding aerators includes tensioning the chains frequently, cleaning dirt and mud from sprockets, and lubricating the chains. Without such maintenance the chains on such aerators will eventually rust, break, or come off. Even if all of this maintenance is completed, the chains still tend to break down due to other chain related issues. Depending on use, after a few years, the chains and sprockets will need to be replaced which is very expensive and very time consuming, and normally needs to be done by a professional due to the complexity of the machine.
Even with all this maintenance and high operating costs, professional contractors are switching to riding aerators due to their high productivity over walk-behind aerators. Thus, there is a need for a riding aerator that does not have the drawbacks of the current riding aerators that have the daily maintenance requirements and expensive replacement costs associated with the chains and sprockets.


An aerosol antiperspirant composition is provided. The aerosol antiperspirant composition includes a propellant having a concentration from 70% to 90% by weight of the aerosol antiperspirant composition and an antiperspirant composition. The antiperspirant composition includes one or more liquid materials, wherein the one or more liquid materials comprise one or more non-volatile silicone fluids having a concentration from 40% to about 70% by weight of the antiperspirant composition, an antiperspirant active particulate, one or more non-antiperspirant active particulates that are substantially inert, wherein the one or more non-antiperspirant active particulates have a concentration from 10% to 30% by weight of the antiperspirant composition. The antiperspirant composition has a total particulate concentration from 30% to about 60% by weight of the antiperspirant composition.

Body odor may be generated in the area under the arms due to a high concentration of sweat glands. While perspiration is odorless, it contains natural oils that can be nutrient source for bacteria living on the skin. These bacteria interact with the natural oils, converting them into odor producing compounds. Antiperspirant compositions contain an active, such as an aluminum salt, that reacts with the electrolytes in perspiration to form a plug in the ducts of sweat glands. The plugs prevent perspiration from exiting the duct, thereby depriving the bacteria of water and a food source. Antiperspirant compositions may be applied to the skin in either a contact type product form, e.g., a stick or roll-on, or non-contact type product form, such as an aerosol spray. Aerosol spray devices that dispense an antiperspirant composition are known in the art. Various examples are described in U.S. Pat. Nos. 4,152,416; 4,806,338; 4,840,786; 4,904,463; 4,935,224; 5,298,236; 5,605,682; 5,814,309; 7,815,899; EP 674,899; WO 96/04884; WO 2004/014330; and WO 2007/001842.
Many aerosol antiperspirant users desire a product that minimizes the appearance of residue on the skin, has a dry rather than wet feel, has rapid perceived drying, is not sticky, and provides a cool/fresh feeling at time of application. Other desired product attributes include providing long lasting wetness and/or odor protection, an easily portable form for purses or small bags (as some users may apply the antiperspirant composition more than once a day) and minimizing the gassy cloud that forms during dispensing. While the relative importance/desirability of these characteristics may vary by geographical region and gender and not all users desire all or the same set of characteristics, a generally universal desire among aerosol antiperspirant users appears to exist for a dry rather than wet feel, minimizing the appearance of residue, and/or providing long lasting wetness/odor protection or efficacy.
While some currently marketed aerosol spray devices may provide at least some of these characteristics to varying degrees, there are often tradeoffs involved. For example, many currently available aerosol antiperspirant compositions also incorporate a volatile liquid (e.g., cyclopentasiloxane) as a carrier for the antiperspirant active. The volatile liquid evaporates following application to the skin, resulting in a dry skin feel, but sometimes leaves behind a visible residue (the antiperspirant active) that is subject to flaking and/or transfer to clothing. Flaking (or transfer) of the antiperspirant active may also reduce antiperspirant efficacy. Further in some cases the cyclopentasiloxane may not be deposited well by products containing propellant levels between 75% and 90%, which may further exacerbate the amount of visible residue and flaking mentioned above. Therefore, there is continuing desire to provide improved aerosol antiperspirant compositions and products.

This patent is subject to a terminal disclaimer.

Aerosol antiperspirant compositions, products and methods


A computer system is provided that allows a computer user to easily and effectively maximize the value and utility of the computer system's display screen. In a preferred embodiment, a laptop computer system includes a keyboard unit that includes a computer keyboard mounted to (or within) a system base. A flat-panel display is pivotally mounted relative to the system base, i.e., the back wall thereof. The flat panel display provides a display screen for displaying computer-generated images. An advantageous mounting assembly is provided proximate the back wall of the system base to join the flat panel display to the system base and permit rotational and pivotal motion of the flat panel display relative to the system base. A receiver or port for use in connecting the laptop computer's processor to an ancillary processing system is advantageously provided proximate a front wall of the system base. Rotational motion of the flat panel display relative to the system base permits repositioning of the flat panel display to facilitate optimal viewing by the user, either independent of or in combination with the aforementioned pivotal motion. In further preferred embodiments, the display screen is detachable and may be mounted on a system stand.

1. Technical Field
The present disclosure relates to a computer display system that provides improved versatility and functionality, and more particularly to a computer display system that is advantageously rotatable and/or detachable relative to a keyboard-containing base, thereby providing a highly cost effective and efficacious computer display system.
2. Background Art
In the rapidly evolving computer products industry, significant increases in processing power, storage capacity, and monitor quality have continued to fuel increased adoption and ubiquitous use of computer technology. Beyond the desktop computers that are found in most homes and offices, portable laptop and/or notebook computers have continued to gain market penetration and adoption. Key factors feeding the continued advent of laptop computers include improved energy usage/storage, reduced weight, increased processing speed, increased storage capacity, and improved monitor quality.
Laptop computer users frequently utilize their laptop as their primary and/or exclusive computer system. Other laptop computer users employ their laptop in parallel with a desktop computer. Such users typically coordinate operation of their laptop computer with their desktop computer by transferring files between the two systems, e.g., by copying or backing up files from one to the other, through floppy disk file transfers, and/or by direct file sharing through parallel port communications and enabling software program(s). Given the space/weight constraints associated with laptop computer design, the use of laptop computers generally entails less-than-ideal keyboard designs/layouts and reduced storage capacity relative to traditional desktop computer systems.
Personal digital assistants, palmtops, hand-held computers, electronic books, and pocket computers (collectively, "PDAs") have also grown in adoption and use. These handheld devices generally combine computing, telephone/fax, and networking features. A typical PDA can function as a cellular phone, fax sender, and personal organizer. Unlike portable computers, most PDAs began as pen-based systems, using a stylus rather than a keyboard for input, and utilizing handwriting recognition features. Some PDAs can also react to voice input by using voice recognition technologies. PDAs of today are generally available in either a stylus or keyboard version.
In utilizing both laptop and desktop computer systems, the quality, flexibility and operation of the monitor is of importance to the overall computer system functionality and desirability. Thus, efforts have been devoted to developing improved computer monitors that offer superior image quality and reliable operation. Recently, flat-panel monitors have been commercialized that offer significant advantages to users, e.g., reduced space requirements, improved aesthetic appearance (e.g., at the desktop), and excellent visual acuity. Laptop computers generally employ flat-panel monitors for reasons of necessity, given space/weight constraints and the desire to pivotally mount the monitor relative to the base/keyboard for system protection and portability. At present, flat-panel monitors are substantially more expensive than conventional CRT monitors of comparable size.
Development efforts have been devoted to increasing the flexibility of computer systems as they relate to operation and use of computer monitors. U.S. Pat. No. 5,978,211 to Hong describes a flat-panel monitor permanently affixed to a stand. The stand includes an interface circuit positioned therewithin for connecting the flat-panel monitor, e.g., a liquid crystal display (LCD), to the host computer system and power supply. A dual-axis hinge assembly is provided that includes a horizontal shaft that permits some degree of rotation about a vertical shaft in the stand. Similarly, U.S. Pat. No. 5,870,280 to Cho discloses a base for an LCD that includes a pivot assembly that cooperates with a rotary disc. The Cho pivot device can be inclined up and down, and rotated left and right to some degree. A further pivotal/rotatable mechanism for use with an LCD view finder of a video camera is described in U.S. Pat. No. 5,982,429 to Kamamoto et al.
To increase the flexibility associated with computer systems, efforts have also been devoted to facilitating detachability of certain components. Thus, U.S. Pat. No. 5,793,606 to Cubbage et al. describes an LCD that is detachable/removable from a portable computer system, and an associated stand assembly having particular applicability to presentation systems and/or applications. The LCD display is formed with a hinge that allows variable viewing angles, whether the LCD is attached or detached from the portable computer system. U.S. Pat. No. 5,805,415 to Tran et al. describes a notebook computer having a detachable display and an accessory stand to support the detached display that may include multiple arms to provide greater pivotal flexibility. A further detachable display unit is described by Kim in U.S. Pat. No. 5,796,576. A foldable display screen is disclosed in U.S. Pat. No. 5,926,364 to Karidis, which forms a viewing angle for the display screen atop the system's keyboard.
Despite efforts to date, computer users who desire to utilize a flat-panel display with their desktop computers have essentially one choice: purchase a flat-panel display that will be used exclusively with the desktop computer system, at substantial cost (and potential redundancy with his/her laptop computer). Prior art teachings allow a computer user to connect his/her laptop computer to his/her desktop computer system, using the output ports at the rear of the laptop or its external expansion unit ("docking station"), but for the limited purpose of using the desktop computer system's conventional CRT monitor and/or other external equipment. Prior art teachings have also suggested monitor detachability from laptop/notebook computer systems for specific and limited purposes, namely to allow: (i) better viewing of presentations running on the laptop/notebook computer; (ii) ergonomic viewing of the monitor while using the laptop/notebook computer, i.e., positioning of the monitor display with greater independence relative to the laptop/notebook computer's keyboard/central processing unit, or (iii) ease of maintenance of the monitor/screen. None of these options is desirable and/or addresses the range of issues confronting users of laptop/notebook computer systems, and an improved, efficient, cost effective system is needed.


The present invention discloses a constant on-time isolated converter comprising a transformer with a primary side and a secondary side. The primary side is connected to an electronic switch and secondary-side is connected to a load and a processor. The processor is connected to a driver on primary side through at least one coupling element and to the electronic switch. The processor receives an output voltage or an output current across the load generating a control signal accordingly. The driver receives the control signal through the coupling element and accordingly changes the ON/OFF state of the electronic switch, regulating the output voltage and the output current via the transformer, where the duration of the ON/OFF state of the electronic switch is determined between the moment control signal changes from negative to positive and the moment it changes from positive to negative to achieve a high-speed load transient response.

With recent advances in technology, electronic products have been developed to meet the diverse needs in everyday life. As these products are made of various electronic components with different power supply and voltage requirements, the AC power supply from wall needs to be converted to appropriate voltages for each of the electronic components to ensure proper operation.
Conventional AC/DC Converters implement an isolated voltage divider design. After coupling the AC power with rectifiers, a transformer is used to convert the high voltage AC power to low voltage DC power that can be used by the devices. As shown in FIG. 1, the conventional power converter includes a transformer 10, which includes a primary side connected to an electronic switch 12 and a secondary side connected to a load 14, an output capacitor 15 and a voltage divider 16 connected to a processor 18. Through a photo-coupler 20, the processor 18 is connected to a controller 22 that is connected to electronic switch 12 to control its switching state. When a voltage is applied across load 14, the voltage divider 16 retrieves a feedback voltage from the load and sends it to the processor 18 that generates an analog signal accordingly and then transmits it from the secondary side through the photo-coupler 20 to the controller 22 in the primary side. Controller 22 changes the ON/OFF state of electronic switch 12 according to this analog signal. Since the processor 18 comprises of TL431 (three-terminal programmable shunt regulator) and VM (voltage-mode) compensation circuit, it uses zero/pole compensation to compensate the loop gain and bandwidth to reduce the ripple signal of the load voltage, stabilizing the whole system. However, the controller 22 is located on the primary side and thus cannot detect the load voltage directly. There is also delay in TL431 and the VM compensation circuit transmitting the signal generated from the feedback voltage of the load to the controller 22, resulting in the load voltage not being stabilized quickly. Furthermore, it is difficult to be controlled in a continuous current mode (CCM) when having a synchronous rectifier in the secondary side.
It is within this context that embodiments of the present invention arise.

Constant on time (COT) control in isolated converter

Alpha & Omega Semiconductor (Cayman), Ltd.


An object is to provide a method for teaching the position of a semiconductor wafer automatically and accurately without relying on the sight of an operator as well as a teaching jig that is used for the above method.

In semiconductor manufacturing facilities, teaching reproduction type robots are frequently used for transport of a semiconductor wafer between a container and a processing apparatus or between processing apparatus. Work of teaching such a robot is such that an operator manually teaches a robot the position of a semiconductor wafer by manipulating a teaching pendant while looking at the semiconductor wafer that is placed inside a container or the like.
Other methods are also available, examples of which are a method of directly inputting the position of a semiconductor wafer on the basis of a system drawing of semiconductor manufacturing facilities (i.e., a drawing indicating positional relationships between robots, containers, etc.) and what is called off-line teaching in which the position of a semiconductor wafer is taught while a simulation is performed on a personal computer. However, even with those methods, it is necessary to directly teach a robot manually for each apparatus to correct for calibration errors of the robot itself, errors resulting from the accuracy of finishing of each apparatus, attachment errors, etc.
Various kinds of what is called auto-teaching have been proposed in which a distance sensor is attached to the hand of a robot and the robot is positioned automatically by detecting a subject being transported with the distance sensor (e.g., Japanese Patent No. 2,898,587 and JP-A-10-6262).
However, in conventional methods, in many cases it is difficult for an operator to approach a container or a processing device. It may be difficult or impossible for an operator to directly see a semiconductor wafer, in which case trial-and-error attempts need to be made repeatedly.
Since the quality of teaching work depends on the individual operator, there is a problem that variation occurs in the operation of a robot even in the same system.
In conventional auto-teaching methods, the position of a wafer is estimated on the basis of information detected by a distance sensor that operates in one direction. This results in a problem that the accuracy of the direction of a wafer is not satisfactory though the distance between a wafer and a robot can be determined with relatively high accuracy.
Conventional teaching jigs are composed of a large disc portion and a small disc portion and hence are thick, which leads to a problem that the installation space is restricted in height.

Wafer position teaching method and teaching jig

Abstract: To this end, in the invention, a teaching jig 11 is detected by a first transmission-type sensor 6 that is provided at the tips of a wafer gripping portion 5 of a robot. The teaching jig 11 is composed of a large disc portion 12 that is the same in outer diameter as a semiconductor wafer and a small disc portion 13 that is concentric with the large disc portion 12. The teaching jig 21 is detected by a second transmission-type sensor 18 that is provided on the wafer gripping portion 5. The second transmission-type sensor 18 is mounted on a sensor jig 15 so as to be detachable form the wafer gripping portion 5.


A nightlight provides therapeutic effects on the body and mind including promoting relaxation, sleep and wakefulness. The nightlight includes a light source, a central processor, one or more controls, and a power supply. The light source produces at least three illumination modes including a sleep readiness mode, a sleep help mode and a wake-up mode. The sleep readiness mode produces monochromatic light of various selectable colors at about 40 lumens which may undulate in luminosity. Meanwhile, the wake-up mode produces substantially full spectrum light at higher luminosity. The controls allow a person to control the various light modes including selecting colors, time periods for activation, and transitions between colors during the sleep help mode. Moreover, the nightlight may include biological sensors for measuring physiological activity of the body. The nightlight may be incorporated into a bedside alarm clock which includes numerous features found in a traditional alarm clock.

The present invention relates to "nightlight" type lighting fixtures. Moreover, the present invention relates to lighting apparatus for providing therapeutic effects on the human body and mind.
Human eyes are sensitive to light in a very small region of the electromagnetic spectrum labeled "visible light". This visible light range corresponds to a wavelength of approximately 400-700 nanometers (nm) and a color spectrum of violet through red. As reflected in FIG. 4, the visible colors from shortest to longest wavelength are violet, blue, green, yellow, orange and red.
It has long been recognized that light can have profound psychological as well as physiological effects on the human body. An example of a human organ whose regulatory function is responsive to light is the pineal gland which secretes the hormone melatonin. The hormone is released during periods of darkness, while production is abruptly halted when the eyes perceive bright light. Melatonin is distributed throughout the body via the blood and cerebrospinal fluid and can affect the function of organs by which it is metabolized to influence sleep cycles, feeding cycles, reproduction cycles and other biological rhythms. It has therefore been suggested that phototherapy may effectively be employed to correct melatonin imbalances and correct sleep cycles which may have been altered from stress, jet lag, life in the polar regions, or changes in the sleep pattern.
Additionally, it has been found that some of the body's responses to light are acutely dependant on specific characteristics of the light such as the light's wavelength and intensity. Further, it has been determined that particular bodily responses can be produced or enhanced by varying the light's characteristics according to certain sequences or patterns. For example, U.S. Pat. No. 5,265,598 describes an apparatus for providing a phototherapy method where various isolated electromagnetic energy patterns are directed to an observer's eyes in an effort to induce a state of homeostasis.
Various attempts have been made to develop lighting apparatus in the home for inducing sleep or wake-up. For example, U.S. Pat. No. 6,236,622 describes a nightlight type lighting fixture which incorporates an alarm clock. Moreover, the lighting fixture provides lamp modes including a wake-up cycle and a sleep cycle which gradually increase and decrease according to the desires of the user. U.S. Pat. No. 5,197,941 discloses a travel alarm clock including a lamp, a speaker and an ion generator for producing ionized air. The device is intended to induce sleep and wake cycles by varying the lamp, sound and ion levels. Numerous references including U.S. Pat. Nos. 5,954,629; 5,259,830 and 5,242,376 describe masks or goggles for producing light in specific frequency ranges for inducing sleep. Still additional references including U.S. Pat. No. 5,167,610 and U.S. Pat. No. 5,928,133 disclose apparatus for inducing sleep which include biological monitors for monitoring brainwaves or respiration.
Unfortunately, prior art devices do not provide a natural environment lamp for use in the bedroom which produces light in specific frequency ranges and modes so as to provide therapeutic effects to enhance sleep readiness, sleep help and wake-up.


The present invention provides a splittable composite fiber having improved processability on carding and superior splitting property by a splittable composite fiber comprising at least two thermoplastic resin components, and having a structure wherein a part of at least one of the components projects from the surface of the fiber.

In recent years, woven and non-woven fabrics made of ultra-fine fibers have widely been used because of their high degree of softness, good touch, and excellent wiping property, as well as high strength in the case of non-woven fabrics. One commonly used method for fabricating non-woven fabrics from ultra-fine fibers is disclosed in Japanese Patent Publication No. 48-28005 (1973), in which a non-woven fabric is fabricated by integrating composite fibers each comprising at least two resin components that have poor compatibility with each other--known as splittable composite fibers--into a web through use of a dry or wet method, then splitting and entangling the fibers through the physical impact of a high pressure fluid or the like.
However, since such splittable composite fibers are required to be easily split by physical impact, thermoplastic resins having poor compatibility with each other are combined, resulting in the difficulty of carding when the web is formed through dry carding or the like, because static electricity is generated due to the formation of split portions during the process, and neps are produced due to the reduction of fiber fineness. If splitting is reduced, on the other hand, the difficulty of carding is improved, but the composite fibers will become difficult to split by physical impact, resulting in poor processability.
An object of the present invention is to solve the problems in processing prior art splittable composite fibers described above, and to provide a splittable composite fiber which can be easily split.


An internal combustion engine intake device is provided for an internal combustion engine such that intake device that can reduce the vibration of the throttle chamber of an internal combustion engine. The intake device has an intake air collector, a vacuum tank and a first air induction pipe. The vacuum tank is arranged closely adjacent to the intake air collector. The first air induction pipe extends upstream from the intake air collector in such a manner as to be closely adjacent to the vacuum tank. Preferably, the first air induction pipe is integral with the intake air collector and the vacuum tank.

1. Field of the Invention
The present invention generally relates to an intake device for an internal combustion engine.
2. Background Information
In the past, there have been several proposals (e.g., Japanese Laid-Open Patent Publication No. 10-231760 (pages 1 to 3, FIGS. 1 to 4)) for an intake device comprising an intake air collector, an air induction pipe that extends upstream from the intake air collector, and intake branches that extend downstream from the intake air collector.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved intake device. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.

Internal combustion engine intake device


A method for separating an encoder shaft of an angle encoder from a drive shaft, which are axially aligned with each other along an axial direction and are self-lockingly braced on each other by a press fit along the axial direction and a central fastening screw, which connects the encoder shaft and the drive shaft in the axial direction. A head of the fastening screw rests against an end of a bore of the encoder shaft, which receives a shank of the fastening screw, and a thread of the fastening screw is screwed into an internal screw thread of the drive shaft for bracing the encoder shaft and the drive shaft. The method includes partially turning the fastening screw out of the internal screw thread of the drive shaft and canceling the press fit by generating an axially oriented force acting between the head of the fastening screw and an end of the encoder shaft opposite the press fit.

1. Field of the Invention
The present invention relates to a method for separating an encoder shaft of an angle encoder from a drive shaft, which are axially aligned with each other and are self-lockingly braced on each other by an axial press fit and a central fastening screw, which connects the shaft of the angle encoder and the drive shaft in the axial direction. The present invention further relates to a device for separating this shaft of an angle encoder and this drive shaft.
2. Description of the Related Art
Angle encoders are used as measuring devices for the controllers of electrical drive mechanisms and make measured values available to a position and rpm regulator, as well as for electronic commutation. They are either installed on the housing of the electrical drive mechanism or installed in the drive mechanism housing. FIG. 1 shows an angle encoder 2 installed on the housing of an electrical drive mechanism 1 and containing an encoder shaft which is rigidly connected with the drive shaft of the electrical drive mechanism 1. The self-locking connection of the two shafts, which are axially aligned with respect to each other, is provided by a press fit which is produced by an inner or outer cone of the encoder shaft and a corresponding outer or inner cone of the drive shaft, or by a cylindrical and hollow-cylindrical form fit of both shafts, and a central fastening screw, which connects both shafts with each other in the axial direction. The self-locking bracing of both shafts is accomplished by tightening the fastening screw, whose shank has been passed through a central bore in the encoder shaft, whose screw thread is screwed into an internal screw thread of the drive shaft, and whose screw head rests against the front or bottom of a bore in the front of the encoder shaft.
FIG. 2 shows a longitudinal view through an angle encoder 2, which has been inserted in an installation space of a drive housing 10 of the drive mechanism 1 and into which a drive shaft 4 projects, which is supported by a drive bearing 11 on the drive housing 10. The angle encoder 2 has an angle encoder housing 20, in which a stationary element is arranged, on which a scanning unit 23, 24 for scanning a graduation or code disk 22 and an encoder shaft 3, which is rotatably seated in the stationary element and supports the graduation or code disk 22, are fastened, and which is seated on the stationary element by means of an encoder bearing 21. The angle encoder 2 is coupled by its stationary element to the drive housing 10 in a torsion-proof manner, wherein the torsion-proof coupling can be provided in accordance with EP 0 762 082 A, for example by a stator coupling 15 by radial clamping at the inner circumference, or in the installation space of the drive housing 10.
The drive shaft 4 has an inner cone 40, into which the outer cone 30 of the encoder shaft 3 is pushed. The encoder shaft 3 contains a central, axially directed bore 31, through which a fastening screw shank 51 of a fastening screw 5 has been pushed, whose fastening screw head 50 rests against the front face, or a recess 32 in the front face, of the encoder shaft 3. A fastening screw thread 52 engages an internal screw thread 42 of a blind bore 41 of the drive shaft 4, which is aligned with the central, axially directed bore 31 of the encoder shaft 3.
The outer cone 30 of the encoder shaft 3 is pulled into the inner cone 40 of the drive shaft 4 by tightening the fastening screw 5, and a self-locking press fit between the encoder shaft 3 and the drive shaft 4 is produced in this way.
Accordingly, when removing the angle encoder 2 from the electrical drive mechanism 1 it is necessary after the fastening screw 5 has been removed to pull the encoder shaft 3 and the drive shaft 4, which are self-lockingly braced on each other, apart from each other, or to push them apart, with a considerable force application. In accordance with the prior art, the pushing apart of the encoder shaft 3 and the drive shaft 4, which are braced on each other, is performed with different push-off methods and push-off devices, two of which are represented in FIGS. 3 and 4 and will be briefly explained in what follows.
For pushing the encoder shaft 3 off the drive shaft 4, with which it is self-lockingly connected, the central fastening screw 5 is turned out of the internal screw thread 42 of the drive shaft 5 by a hexagon screwdriver. Thereafter, in accordance with FIG. 3 a setscrew 62 is screwed into the internal screw thread 42 of the drive shaft 4 by a hexagon screwdriver of lesser jaw size, so that the internal screw thread 42 of the drive shaft 4 is not damaged during the subsequent push-off process. Subsequently a special push-off screw 61 is screwed into an internal push-off screw thread 33 of the encoder shaft 3, which is arranged in the central bore 31 in the area of the outer cone 30 of the encoder shaft 3, until the end of the push-off screw 61 comes into contact with the setscrew 52 and the encoder shaft 3 and the drive shaft 4 are axially pushed apart by this, so that therefore the self-locking press fit between the drive shaft 4 and the encoder shaft 3 is cancelled.
Accordingly, with this push-off method two additional screws, namely the setscrew 62 and the push-off screw 61, as well as two different tools for the screws 61, 62 of different head size, are required for separating the encoder shaft 3 from the drive shaft 4, and therefore the angle encoder 2 from the drive mechanism 1.
FIG. 4 shows a further known push-off device, or push-off method, wherein a special push-off screw 63 is supported in the blind bore 41 of the drive shaft 4, which has the internal screw thread 42, and with its external screw thread 64 engages the push-off screw thread 33 of the encoder shaft 3, so that by screwing in the special push-off screw 63, the self-locking press fit between the outer and inner cones 30, 40 of the drive and encoder shafts 3, 4 is cancelled and thereby the angle encoder 2 can be removed from the electrical drive mechanism, for example for maintenance or inspection purposes.
With this push-off method the parts necessary for pushing the encoder shaft 3 off the drive shaft 4 are reduced to the special push-off screw 63 and an additional tool.
However, it is disadvantageous that a special screw is required as the push-off screw 63, which possibly must be adapted to different depths of blind bore 41, depending on the type of the drive shaft 4. Moreover, the diameter of the special push-off screw 63 is relatively narrow and the special push-off screw 63 must be embodied to be relatively long, so that it becomes unstable.
Possibly different depths of the blind bore 41 in different drive shafts 4, which depend on the drive mechanism 1, are also problematical, which makes respectively special push-off screws 63 necessary. This push-off method cannot be employed in connection with a continuous internal screw thread of drive shafts.
A method and a device for pushing an encoder shaft of an angle encoder off a drive shaft, which are connected with each other by a conical press fit, is known from JP 1-270753 A. For pushing the encoder shaft off the drive shaft, a push-off screw thread is arranged in the housing of the angle encoder, which presses directly on the end of the drive shaft. Accordingly, the force required for push-off also acts on the angle encoder housing which, in case of an appropriately solid connection between the angle encoder shaft and the drive shaft, and therefore of the force required to separate the two shafts, can be deformed or destroyed.

Device for separating an angle encoder shaft from a drive shaft


An image processing method, for extracting a base component from image data including a detailed component and the base component, containing the steps of extracting the base component by application of an edge preserving filter to the image data; and correcting the portion, of the extracted base component, corresponding to a predetermined frequency component of the original image data.

1. Field of the Invention
The present invention relates to an image processing method, an image processing apparatus and an image processing program, particularly to an image processing method, an image processing apparatus and an image processing program capable of extracting at least the base components contained in image data, wherein this image data contains the detailed components and the base components.
2. Description of the Related Art
The image data contains the detailed components wherein the signal value of each pixel varies on a step-by-step basis as compared with that of the peripheral pixel, and the base components wherein the signal value of each pixel does not vary on a step-by-step basis as compared with that of the peripheral pixel. The detailed components as used herein denote minute changes in an image, whereas the base components indicate changes in almost uniform brightness within a predetermined range of the image.
In the waveform diagram showing the signal value of the image data given in FIG. 13, the solid line indicates the signal value of the image data. To be more specific, the image data contains the detailed components wherein the signal value of each pixel varies on a step-by-step basis as compared with that of the peripheral pixel, and the base components wherein the signal value of the detailed components is shifted by a predetermined amount.
To compress the dynamic range of the image data in various forms of image processing, the base component of the image data is separated from the detailed component, and this base component alone is compressed first. Then the base component and detailed component are synthesized. Such a procedure is often utilized.
The aforementioned procedure compresses the base component where the amplitude of the signal value is greater, but fails to compresses the detailed component. Thus, although the portion pertaining to brightness of the image is compressed, the subtle delineation or delicate feeling of the image are preserved undamaged. Such an advantage is provided by the procedure.
In the separation between the base component and detailed component, the base component is identified as a low frequency component, while the detailed component is assumed as a high frequency component. The difference in frequency components is employed to implement separation between the base component and detailed component.
To extract the base component when implementing the separation, a filter having a predetermined magnitude (a smoothing filter) is applied to the relevant image, and the average value of the peripheral pixels. In this case, assume the image data containing the portion (edge portion) wherein the signal value of the base component exhibits an abrupt change, as shown in FIG. 14(a). Here, if the smoothing filter is used to extract the base component, the edge portion contained in the original base component, namely, the signal value of the base component exhibits an abrupt change which will cause blur, as shown by the solid line in FIG. 14(b), which means that the edge portion becomes less sharp and smoother.
When the base component extracted in the manner is compressed (FIG. 14(b)) and is synthesized with the detailed component, a blurred component or faint false contour-like component called "halo" will appear, as shown in FIG. 14(c).
Originally, the halo is not compressed because the high frequency component originally contained in the base component is not detected as a base component. This is considered to give an adverse effect to detailed components.
To prevent the halo from occurring, it has been proposed to use a filter (called the edge preserving filter) capable of identifying the high frequency component as the edge portion and extracting the base component while preserving the high frequency component of this edge portion.
FIG. 15 shows an example of the operation by the edge preserving filter. Assume the image data wherein an edge portion is present in the base component as shown in FIG. 15(a).
In this case, if the edge preserving filter, instead of the smoothing filter shown in FIG. 14, is used to extract the base component, the edge portion of the base component, as well as the original base component (wavy line of FIG. 15(b)) is kept clear without being blurred, as shown by the solid line of FIG. 15(b).
Thus, when the base component (FIG. 15(b)) extracted with the edge portion preserved is compressed and the detailed portion is synthesized, then an image data free from halo can be produced, as shown in FIG. 15(c).
As a result, the base component having a large amplitude of signal value is compressed without the detailed component being compressed. This arrangement ensures that the portion such as brightness in the image is compressed, with the delicate delineation of the image kept undamaged.
The edge preserving filter includes various types of filters incorporating diverse techniques such as a bilateral filter, ε-filter and median filter. The details of the bilateral filter are given in "Fast Bilateral Filtering for the Display of High-Dynamic-Range Images" Fredo Durand and Julie Dorsey, SIGGRAPH 2002.
To get the similar results as those of the edge preserving filter, only the smaller amplitude component, not the greater amplitude component, is smoothed, whereby the base is extracted. This method is disclosed in the Official Gazette of Japanese Patent 2001-275015 (FIG. 1 on page 1).
According to the method disclosed in the documents, use of an edge preserving filter provides the advantage of extracting the base hardly allowing the high-frequency edge portion to be blurred. However, in order to ensure thorough extraction of the edge portion, processing is applied in such a way that the portion over a certain frequency is identified as the edge portion. This arrangement allows part of the portion of intermediate frequency to be identified as the edge, with the result that detection error occurs. Thus, smooth transition of the pixels of that portion will be lost and a pseudo edge will be produced.
Assume the image data including a portion where the signal value of the base component exhibits a smooth transition (smooth edge portion), as shown in FIG. 16(a). In this case, if the base component is extracted using the edge preserving filter, the smooth portion contained in the original base component (wavy line of FIG. 16(b)) is adversely affected by the intermediate through high frequency components, as shown by the solid line of FIG. 16(b). This will produce a detection error. Thus, the base component to be extracted will exhibit a waveform wherein the signal value is subjected to abrupt changes.
If the base component extracted on the basis of detection error is (FIG. 16(b)) is compressed and is synthesized with the detailed component, a component similar to the pseudo contour known by the name of "edge error" will appear, as shown in FIG. 16(c).
Since the edge preserving filter does not extract the high frequency component having a smaller amplitude, it can be used to eliminate noise. However, some noise components pass through the edge preserving filter, because of frequency component or amplitude. Accordingly, the edge preserving filter is not sufficient when used to eliminate noise. Such a problem has been left unsolved in the conventional art.

Image processing method, image processing apparatus and image processing program


An electricity supply element and the ceramic separator thereof are provided. The ceramic separator is adapted to separate two electrode layers of the electricity supply element for permitting ion migration and electrical separation. The ceramic separator is made of ceramic particulates and the adhesive. The adhesive employs dual binder system, which includes linear polymer and cross-linking polymer. The adhesion and heat tolerance are enhanced by the characteristic of the two type of polymers. The respective position of the two electrode layers are maintained during high operation temperature to improve the stability, and battery performance. Also, the ceramic separator enhances the ion conductivity and reduces the possibility of the micro-short to increase practical utilization.

1. Field of Invention
The present invention relates to an electricity supply element, in particular to an electricity supply element having a ceramic separator to enhance heat tolerance and the ion conductivity.
2. Related Art
The separator (film) is an important unit of an lithium battery. The separator is disposed between the positive electrode layer and the negative electrode layer. The separators are used to electrically insulate the negative and positive electrode layers so that the battery electrolyte forms the only ionically conducting path therebetween. In order for the separators to provide this insulating function, the separators must exhibit a low electrical resistance, must be chemically stable in the electrolyte environment, must resist stiffening and cracking, must be wettable to the battery electrolyte, and must limit active material transport.
The microporous polyolefin film, such as PE or PP, is widely used to manufacture battery separators because it is chemically stable and outstanding in physical properties. The melting point of the PE is about 130° C., and the melting point of the PP is about 160° C. Limited thermal and mechanical stability of the polymer separator may lead to overheating of the battery and explosion caused by separators melting and rupturing. Thermal operation window of separator in a battery is determined by shutdown temperature and melt down temperature. Therefore, in recent years, ceramic separators with high thermal stability and good wettability are developed.
There are two types of the ceramic separator. The first type is used the ceramic particles as the main material of the separator to replace the polyolefin, such as U.S. Pat. No. 5,342,709. The second type is utilized the ceramic particles to be coated on a film made of PET, PEN or PI, such as US patent application publication no. 2008/0138700.
For the first type, the ceramic particles of the separator are bonded with the electrode layer by the adhesive. The binder system of the adhesive is similar to the binder system of the electrode layers. Therefore, the solvent systems are also similar. When drying the solvent after coating, the particles rearrangement and the adhesive entanglement are occurred and the holes are produced in the bulk and at the interfaces. The holes would be a good path for ion mobility. However, due to the solvent is removed in a short time, the holes may be huge to induce micro-short. Therefore, the electrical insulation of the electrodes in battery will be compromised.
For the second type, the adhesive, such as Polyvinylidene fluoride (PVDF) or PVDF-HFP, is used to bind the ceramic particles on the surface of a substrate film. Moreover, the film has holes to permit the ion migration. The ceramic particles are coated on the substrate film meant to ensure the electrical insulation of the electrodes at abnormal conditions. However, the adhesion between the PVDF or PVDF-HFP, and material of the substrate film, such as PET, PEN or PI, is weak, and the ceramic particles are easy to peel off. To increase the particle's adhesion to the substrate film, the percentage of the adhesive has to be higher. However, the ion conductivity would be lowered accordingly.
Also, if the amount of the ceramic particles is raised to enhance the ion conductivity, the amount of the adhesive also has to be raised accordingly to maintain enough adhesion. Therefore, the percentage of the ceramic particles is limited, only 40% at most. The ion conductivity is limited. To increase the ion conductivity, the plasticizer or non-solvent are added into the adhesive. After the formation of the separator film, the plasticizer or non-solvent is removed to obtain holes for ion mobility to enhance the ion conductivity.
Furthermore, the ceramic particles may easily absorb water, which will significantly deteriorate battery performance. To remove the absorbed water of the ceramic particles, it has to be heated at a temperature over 190° C. However, the melting point of the adhesive is not high enough. For example, the melting point of the PVDF is about 170° C., and the melting point of the PVDF-HEP is about 120-150° C. When the separator is heated at 190° C., the adhesive would melt. The distribution of the holes within the separator would be changed to worsen the electric property of the battery. Even adding the plasticizer or non-solvent as above mentioned, the holes would be refilled by the molten adhesive to lower the ion conductivity.
On the other hand, if the materials of the adhesive with high heat tolerance are used, such as epoxy resin, acrylic acid resin, polyacrylonitrile (PAN), the thermal stability and the adhesion will be improved. However, these materials would form such cross-linking network with dense structure which significantly reduces ion migration and final battery performance. In other words, the distribution of the holes is not suitable for ion migration. Therefore, the ion conductivity is very low.

Electricity supply element and ceramic separator thereof


A system of managing memory used by communications tasks of a communications network operating with a multilayered communications protocol. Specially formatted buffers are used to contain data to be passed down the protocol stack of a source node, across a communications link, and up the protocol stack of a destination node. Before entering the source stack, message data is presegmented so that each buffer contains only so much message data as may be transmitted as a single data unit from source to destination, even after all layers of the source stack have added layer headers to that portion. Then, when the buffers are being passed within the source stack, any layer may segment the message data by simply unlinking buffers and adding its layer header to each segment. Inter-layer data passing is by means of exclusive access to buffers by one layer at a time. At the source stack, any layer that must send multiple copies of the message data may checkpoint the buffers and thereby regain the same buffers. At the destination stack, the buffers may be reassembled by relinking them.

In the field of data communications, a general definition of a "protocol" is a set of rules governing the exchange of messages between two or more communication devices. Ultimately, communications are between "end systems" in the sense that each end system is either a source or destination, or both, of information. Typically, the end systems are processor-based devices, such as computer workstations.
The use of standardized protocols permits different end systems to communicate even if they are from different manufacturers, or for some other reason have different designs. Communications tasks conforming to the protocols are performed by various processors, controllers, and other "intelligent" devices in the network.
The seven-layer Open System Interconnection (OSI) is a protocol model, developed by the International Standards Organization. Although there are protocol models other than the OSI model, and not all data communications tasks involve all layers of the OSI model, it can theoretically be used to define all aspects of data communications.
Each layer of a protocol, such as the OSI protocol, is a set of tasks to be performed by some sort of intelligent entity, whether in the form of hardware, firmware, or software. In the OSI model, the top three layers (application layer, presentation layer, and session layer) are specific to the users of the information services of the network. The middle layer (transport layer), maintains a communication channel and is a liaison between network service users and the network service providers. The lower three layers (network layer, data link layer, and physical layer) deal with the actual network providing the network services.
In this layered approach to communication protocols, communications may be "horizontal" or "vertical". Horizontal communications are those to "peer" entities of other end-systems. Vertical communications are those between adjacent layers of the same end system.
From a functional viewpoint, an end-system of a communications network can be thought of as a "stack" of protocol layers, residing in and managed by the end system's intelligent devices. On the sending end, user data are generated at the higher layers. Each layer receives a protocol data unit (PDU) from the layer above, which contains the user data and any header data added by prior layers. The layer adds its own control information as a header. At the bottom of the source node's stack, the physical layer transmits the PDU over a data link. The PDU then moves up the stack of the destination node, where at each layer, a peer layer strips off its header to invoke one or more protocol functions.
Implementation of the protocol stack requires some sort of stack management scheme for passing PDU's from layer to layer. Typically, an area of memory, generally referred to as a "buffer" is used to contain all or part of each PDU. An example of an existing stack management method for passing data is based on a first-in first-out queue. Data are contained in a buffer that contains the queue. Each layer uses its own buffer and data is copied from one buffer to another. However, every copying step requires additional processing overhead. The copying of data from one buffer to another is particularly burdensome when a protocol function requires a layer to send multiple copies of a PDU.
In addition to the problem of the overhead required for buffer copying, another problem with existing stack management schemes is the need to implement PDU segmentation. Typically, segmentation requires data to be copied from one size buffer to another, or to be handled as linked lists, which then requires special hardware support.
A need exists for a method of managing a protocol stack that minimizes processing overhead without requiring special hardware. Thus, an object of the invention is a protocol stack management system that avoids the need for physical copying of buffers. Before entering the protocol stack, message data is converted to a special buffer format. An envelope portion of the buffer contains at least a portion of the message, and is sufficiently small that it may contain a PDU to be sent out from the lowest layer of the protocol stack even after all layers have added their headers. A buffer header portion of the buffer contains data for managing sequencing and copying of the buffers. The buffers are passed from layer to layer by means of exclusive access to them, whereby the same memory is accessed by only one layer at a time.
In this manner, message data is "pre-segmented" into buffers. The buffers are passed from layer to layer, as a linked list representing a PDU, without copying. Any layer may segment the PDU by unlinking the buffers and adding its layer header to each buffer envelope, thereby creating multiple PDU's, one in each buffer. A peer layer of the segmenting layer uses data in the buffer to reassemble the PDU. If a layer of the source stack needs to re-send a buffer or otherwise use multiple copies, that layer may "checkpoint" the buffer so that the layer will regain the same buffer. At the destination stack, the PDU's may be reassembled by linking buffers, and the original message may be reconstructed.
An advantage of the stack management system of the invention is that it is faster than systems that require physical copies from layer to layer within an end system. It solves the problem of handling blocks of message data that are larger than the PDU that can be handled by any one layer, without extra processing overhead or special hardware.

Method for implementing a data communication protocol stack