The invention provides a copolymer of ethylene and at least 5 mol % of comonomer units derived from an alkyl acrylate or alkyl methacrylate, wherein the copolymer has a melt index of from 1 to 10,000 g/10 min, and a maximum peak melting temperature of at least 100° C. The alkyl group of the alkyl acrylate or alkyl methacrylate can be a linear or branched C1 to C12 group, particularly n-butyl. The copolymer shows increased heat resistance as characterized by a temperature required to melt 50% of the copolymer of at least 80° C., a temperature required to melt 80% of the copolymer of at least 100° C., a temperature required to melt 100% of the copolymer of at least 110° C. The invention further provides a process for copolymerizing ethylene and an alkyl acrylate or alkyl methacrylate comonomer.

Ethylene is copolymerized with comonomers such as alkyl acrylate or alkyl methacrylate esters or vinyl esters, to create polymers with a different set of properties and attributes not obtainable from homopolymers themselves. Some attributes like adhesion and low temperature toughness, are significantly improved as the content of comonomer(s) is increased. However, increasing comonomer content invariably leads to lower peak melting temperatures, sometimes significantly lower peak melting temperatures, especially in copolymers containing more than about 5 mol % comonomer. As an example, commercially available ethylene vinyl acetate (EVA) and ethylene methyl acrylate (EMA) grades show a significant decrease in peak melting temperature as comonomer content is increased, as shown in FIG. 1 (prior art). These lower peak melting temperatures indicate smaller crystallite sizes that result from shorter runs of uninterrupted, repeating ethylene units in the polymer's backbone. Thus, it is difficult to achieve high melting points with even moderate amounts of comonomer.
Peak melting points can also be significantly reduced by increasing melt index. Data for commercially available, nominally 28 weight % vinyl acetate (VA) copolymers shows a decrease from about 73° C. at 2.3 g/10 min melt index to 63° C. at 420 g/10 min melt index, as shown in FIG. 2 (prior art). These observed trends indicate that using conventional technology, high MI and high comonomer content copolymers will have very low melting points. In certain applications, however, such as hot melt adhesives and some film or molded articles, where heat resistance and strength are particularly important, it would be advantageous to have a copolymer having a combination of high melt index, relatively high comonomer content, and higher melting point.
The use of continuous, back-mixed autoclaves to produce homogeneous ethylene acrylate copolymers is disclosed in U.S. Pat. No. 3,350,372. Copolymer resins produced using autoclave technology are commercially available, and these resins are consistent with the expected trend. For example, as discussed more fully in the Examples herein, at 32.5 weight percent n-butyl acrylate (9.5 mol %), the peak melting temperature of a 330 g/10 min melt index ethylene n-butyl acrylate copolymer available as Enable™ EN-33330 from ExxonMobil Chemical, is poorly defined, with a value about 58.7° C. A lower viscosity grade, with an estimated melt index of about 900 g/10 min and available as Enable™ EN-33900 from ExxonMobil Chemical, has an even lower peak melting temperature of 58.1° C. (see Table 1).
Manufacturers have recognized that the lower melting points of commercially available copolymers are an undesirable limitation, and have attempted to develop technology to increase melting points of ethylene acrylate copolymers (EMA and EnBA) produced in continuous, high pressure autoclaves (see, e.g., U.S. Pat. Nos. 5,543,477 and 5,631,325). These technologies have led to copolymers with peak melting temperatures which are reportedly about 7 to 10° C. higher than other conventionally polymerized copolymers produced in autoclaves.
The first commercial, continuous process developed to produce ethylene alkyl acrylate and alkyl methacrylate copolymers was a tubular reactor process developed by Union Carbide (see U.S. Pat. No. 2,953,551). Tubular reactors are known to be capable of producing ethylene alkyl acrylate and alkyl methacrylate ester copolymers having higher melting temperatures than the same copolymers polymerized in a high pressure autoclave. Commercially available ethylene ethyl acrylate copolymers, produced and sold by Union Carbide since the early 1960's, have relatively high peak melting temperatures compared to autoclave polymerized ethylene methyl acrylate copolymers at the same mole percent comonomer. However, the melting points of copolymers obtainable from these technologies are still undesirably low for some applications.
For further background information, see, for example, WO 00/58093; WO 97/34939; U.S. Pat. No. 5,543,477; DE 3217973; DE 3404744; EP 245773 and EP 575873.

Ethylene alkyl acrylate copolymers with improved heat resistance


A disclosed neural network processing system includes a host computer system, a RAMs coupled to the host computer system, and neural network accelerators coupled to the RAMs, respectively. The host computer system is configured with software that when executed causes the host computer system to write input data and work requests to the RAMS. Each work request specifies a subset of neural network operations to perform and memory locations in a RAM of the input data and parameters. A graph of dependencies among neural network operations is built and additional dependencies added. The operations are partitioned into coarse grain tasks and fine grain subtasks for optimal scheduling for parallel execution. The subtasks are scheduled to accelerator kernels of matching capabilities. Each neural network accelerator is configured to read a work request from the respective RAM and perform the subset of neural network operations on the input data using the parameters.

Machine learning is the science of inducing computing systems to act without being explicitly programmed. Classical machine learning includes various clustering and classification techniques, including K-means clustering, linear and logistic regressions, stochastic gradient decent, association rule learning, and the like. Deep learning is a newer frontier in machine learning. Deep learning is a class of machine learning algorithms that uses multiple layers of nonlinear processing units for feature extraction and transformation. Deep learning algorithms can be unsupervised (e.g., pattern analysis) or supervised (e.g., classification). The deep learning algorithm can be implemented using layers of an artificial neural network (ANN) (referred to herein as a "neural network").
In general, a neural network is a collection of nodes (i.e., the "neurons") that are connected in a graph. A node in a neural network computes a sum of weighted inputs and adds an optional bias to the sum. The output of the node is a function of the final sum (referred to as an "activation function"). Example activation functions include the sigmoid function, the hyperbolic tangent (tanh) function, the Rectified Linear Unit (ReLU) function, and the identity function. Neural network models are often organized into layers of nodes, which define a specific topology, and corresponding weights and biases. The weights and biases are referred to as network parameters.
In general, a neural network includes an input layer and an output layer and can optionally include one or more hidden layers between the input and output layers. A neural network used in deep learning applications typically includes many hidden layers, which gives rise to the term deep neural network (DNN). The layers of a neural network can be densely connected (e.g., each node in a layer is fully connected to all nodes in a previous layer) or sparsely connected (e.g., each node in a layer is connected to only a portion of the nodes in a previous layer). A convolutional neural network (CNN) is a type of DNN that includes one or more sparsely connected layers, referred to as convolutional layers. A CNN is well-suited for processing image or video data. Other types of DNNs include recurrent neural network (RNNs), which are well-suited for processing speech and text data.
Field programmable gate arrays (FPGAs) have been used to implement circuits that accelerate functions called from software. Circuits that accelerate functions called from software are referred to as hardware accelerators. Examples of hardware accelerators include various image filters implemented as FPGA circuits that can be called from image processing software.
Some FPGA-based products are implemented as multiple FPGA dies attached to a silicon interposer and packaged as a single device. Implementing a hardware accelerator on multiple FPGA dies may not be feasible for some applications because the interconnect between FPGA dies may not provide the bandwidth needed to achieve a desired level of performance. In addition, placing and routing a hardware accelerator on multiple dies may be problematic due to limitations of the inter-die interconnect.

Neural network processing system having host controlled kernel acclerators


Disclosed is a peptide trimer in which three peptides of the same chain length having a repeating unit as a fundamental structure represented by the formula:-(-Gly-X-Y-)-wherein X and Y each represent any amino acid residue are tethered to one another such that they are shifted relative to one another in the backbone direction. The peptide trimer is capable of forming a polypeptide having a collagen-like triple helix structure. A method of producing the peptide trimer of the invention and a collagen-like molecular aggregate having a triple helix structure comprised of the peptide trimer unit of the invention are also provided.

Collagen is widely used as a base material for a pharmaceutical product or a cosmetic product, as a biocompatible material for regenerative medicine or drug delivery system, and as a support for tissue culture and the like. Currently available collagen is mainly those obtained by purifying collagen from animals such as pigs and cattle. However, in the case where collagen derived from livestock is applied to humans, a risk of prion infection which may cause BSE has become a problem. Alternatively, collagen derived from plants or fish skin has started to be used, however, it involves a risk of gelatin allergy caused by intake of heterologous collagen. Accordingly, supply of a safe substitute for collagen has been demanded. Recently, construction of genetically engineered human collagen-produced system using various host organisms has been attempted, although it has not come into practical use yet.
Collagen has a structure in which three polypeptide chains form a long triple helix. It is well known that three chemically synthesized peptides having a collagen-like sequence are self-assembling to form the same triple helix structure as collagen, and such structures are used in studies of the structure of natural collagen. Collagen-like polypeptide known in the art include, for example, a polypeptide composed of a repeating unit comprising a peptide unit: [-(Pro-Y-Gly)n-]a (wherein Y represents Pro or Hyp and n represents an integer of 1 to 20) and a peptide unit, [-(Z)r-]b (wherein Z represents a peptide chain composed of 1 to 10 amino acid residues and r represents an integer of 1 to 20)(JP-A-2003-321500). Known supramolecules composed of a collagen-like peptide sequence include, for example, a collagen triblock peptide of Martin et al.: (Glu)5(Gly-X-Hyp-Gly-Pro-Hyp)6(Glu)5 (SEQ ID NO: 7) (Martin, R. et al., Biopolymers 70, 435-444, 2003) and a "peptide-amphiphile" of Fields (Fields, G B, Bioorg. Med. Chem. 7, 75-81, 1999).
However, there has been no report of a supramolecule which is formed through the intermolecular formation of complementary triple helix extending the molecule in the direction of triple helix axis.
An object of the present invention is to provide a polypeptide having a collagen-like triple helix structure and a peptide unit for producing such a polypeptide.

Polypeptide having collagen-like structure


An image detection system having a camera unit for detecting images of the outside area of a motor vehicle, and a protection element that can be moved from a closed position to an open position by a mechanism through a drive. At least one lens of the camera unit is located behind the protection element inaccessible from the outside when the protection element is located in the closed position. At least the lens is released by the protection element for image detection in the open position. At least the camera unit with the mechanism and the protection element is disposed in a first module and the drive is provided in a second module separate from the first module. The first and second modules are mechanically connected to one another by at least one actuation element so that the drive drives the mechanism by way of the actuation element.

Such image acquisition systems, which are used for image acquisition of an outside area of the vehicle are generally known.
For example, such image acquisition systems can be used in the field of assisted parking of vehicles. The camera units produce an image of the outside area for the driver of the vehicle, especially a rear view of the vehicle, which is displayed on a monitor within the vehicle and represents a significant support for the driver during maneuvering. It is known to mount such systems with a camera unit on various vehicle locations, like a bumper, trunk lid or the like.
A camera system for a vehicle is known from document EP 1 648 737 B1 in which the camera unit can be closed by a protective element in order to protect it from external environmental effects when not in use. If the camera unit is used the protective element is pivoted away so that the camera unit can now record the desired images. For this purpose the entire image acquisition system is equipped with an electric motor that acts directly on the protective element via a gear mechanism to transfer the protective element from an open to a closed position and vice versa. The entire unit of the image acquisition system requires considerable space, for which reason this system cannot be arranged on space-critical locations on or in the vehicle.


A sense amplifier circuit for sensing a logic state of a selected memory cell in a memory circuit includes a precharge circuit and a latch circuit. The precharge circuit is adapted for connection to a pair of complementary bit lines corresponding to the selected memory cell and is operative to selectively drive the pair of complementary bit lines to a first voltage in response to a first control signal. The latch circuit is adapted for connection to the pair of complementary bit lines. The sense amplifier circuit further includes a replication circuit adapted for connection to the pair of complementary bit lines. The replication circuit is operative to selectively transfer a voltage representative of a logic state on a first bit line of the pair of complementary bit lines to a second bit line of the pair of complementary bit lines in response to at least a second control signal.

Memory circuits, including, for example, dynamic random access memory (DRAM), are employed in a wide variety of devices and applications. As memory access time requirements are pushed faster and noise immunity requirements are increased, the design of memory circuit architectures to meet such requirements becomes significantly more challenging. Additionally, memory size requirements are continuously increasing, thereby exacerbating speed and noise immunity problems.
Various memory architectures have been proposed to meet certain design criteria, such as, for example, memory access time, often measured as latency. However, although these known memory architectures have had some successes at reducing memory latency, they have often achieved such a reduction in memory latency at the expense of other important design criteria, such as, for example, memory density, noise immunity, power consumption, etc., which are often mutually exclusive design characteristics in a given memory architecture.
Techniques for reliably sensing the logical states of memory cells in the memory circuit architectures also become more difficult to implement as memory performance requirements (e.g., memory access time, noise immunity, memory size, etc.) are pushed. For example, as voltage supply levels are reduced, sense amplifiers in the memory circuits are significantly more sensitive to threshold variations and mismatch. In order to minimize threshold mismatch in the sense amplifiers, it is known to increase transistor dimensions. However, increasing the transistor dimensions increases the overall chip area required by the memory circuits, and is therefore undesirable.
Accordingly, there exists a need for sensing circuitry for use in a memory circuit that does not suffer from one or more of the problems exhibited by conventional sensing circuitry.

Enhanced sensing in a hierarchical memory architecture

International Business Machines Corporation


A driving head for a stirrer can is provided. The stirrer can includes a cover with a rotatable plate having upwardly projecting fingers and further includes a stirrer inside the stirrer can. The driving head is mounted beneath a hollow shelf, includes a driven shaft and a blade fixedly connected to the driven shaft. The blade engages the fingers for driving the stirrer inside the stirrer can. A swan-neck shaped body having an upper portion, connected to the shelf, and a lower portion is provided. The lower portion of the body comprises a grip for engaging the rotatable plate of the stirrer can. The driven shaft projects through the upper portion of the body. A device for preventing rotation of the stirrer can is provided.

The cabinets that are currently used comprise a plurality of shelves arranged one above the other, and having a bottom portion that is provided with driving heads of the small blade type, which driving heads cooperate with fingers arranged on the cover of each can and used for driving a shaft passing through this cover and supporting a stirring screw or the like.
In order to prevent rotation of the cans on the shelves, fixed or movable protruding pins are provided, which are used for securely retaining the base of the can. These protruding pins are often harmful and can cause damage to the cans, particularly when the same are made of synthetic material.
The protruding pins or other means for locking the cans have also the important drawback that they make difficult the cleaning of the shelves to which they are fixedly connected. Moreover, in case of leakage of the can, the apertures provided in the shelves for making or positioning the protruding pins allow flow of paint from one shelf to another shelf.
The invention relates to a new driving head for stirrer cans which allow the use of smooth shelves without any particular member to be provided on these shelves.


A semiconductor device includes: a GaAs chip; and a resin sealing the GaAs chip. The GaAs chip includes: a p-type GaAs layer; an n-type GaAs layer on the p-type GaAs layer; a metal electrode located on the n-type GaAs layer along an edge of the GaAs chip and to which a positive voltage is applied; a device region located in a central portion of the GaAs chip; a semi-insulating region located between the metal electrode and the device region and extending in the p-type GaAs layer and the n-type GaAs layer; and a connecting portion disposed outside the semi-insulating region and electrically connecting the p-type GaAs layer to the metal electrode.

1. Field of the Invention
The present invention relates to a semiconductor device in which a GaAs chip is sealed or encapsulated with a resin, and more particularly to a semiconductor device in which such a GaAs chip has improved moisture resistance.
2. Background Art
There have been proposed resin sealed semiconductor devices in which a semiconductor chip is sealed with a resin [see, e.g., Japanese Laid-Open Patent Publication No. 60-167432 (1985)]. An exemplary such resin sealed semiconductor device includes a GaAs chip as the semiconductor chip. Electrodes are formed along the edges of the GaAs chip, and the device region is formed in the central portion of the GaAs chip.


A spray gun pressurized air control system includes an air adjusting knob, a trigger, a trigger seat within a housing, and a control ring. The air adjusting knob comprises a knob at one end having indicia marked thereon, and a hollow shank at the other end to receive a spring therein. An inner end of the spring engages with one end of an enlarged portion of a pin. The other end of the enlarged portion engages with the bottom portion of an L-shaped plate extending downward from one end of the trigger. By adjusting the knob to a predetermined position, pressurized air may be released from a valve controlled by the trigger.

1. Field of the Invention
This invention relates to spray guns. More particularly, this invention pertains to a spray gun which includes indicia adapted to adjust pressurized air output volume so as to achieve a high quality painting.
2. Prior Art
Many people are increasingly doing their own minor repairs in their homes due to high labor rates of professional service people. In many instances, painting is one endeavor that people prefer to do themselves. However, prior art spray guns as shown in FIG. 5 are generally composed of a housing 10 having a paint reservoir detachably mounted to the bottom portion of the housing 10 with a linking block 40 shaped in the form of a reversed letter U which has one end pivotally secured to the trigger 30 at a cavity area 50. The other end of the linking block 40 has a pin 60 extending therethrough. One end of the pin 60 is secured to an adjusting knob 70. This prior art spray gun has a number of disadvantages. The trigger 30 of such prior art spray guns may be actuated by children and cause physical injury. In other instances when the job is interrupted, it is difficult to adjust output volume of pressurized air. A further disadvantage is that children may be accidentally pinched by the linking block 40 or the pin 60. It is therefore an object of this invention to overcome the disadvantages previously described.

Spray gun pressurized air control system

No. 9-1, Lane 271, Sec. 3, Roosevelt Rd.


Method of printing individual header cards with a limited amount of information, such as a barcode, employing continuous movement of each of the header cards through a gap defined between a backup roll and a thermal printing head, each header card partially wrapping the backup roll only in the immediate vicinity of the printer head.

In the retail sales industry, automated tracking, control, and other functions relating to inventory offered for sale and/or sold has become the "norm". To this end, a barcode identified as a Universal Product Control has been developed. A UPC code is assigned to each product offered for sale. Commonly this code identifies the product, the seller, the sales price, and/or other information. Each UPC code is specific to its assigned owner/user.
Because a UPC barcode is specific to each user, the UPC barcode must be applied to individual items offered for sale by a specific user. Where large volumes of a product are sold to a given entity, the manufacturer can economically justify preprinting that entity's UPC barcode directly onto the packaging for a given product. On the other hand, where a specific user's purchase volume is relatively small, the user must attend to the application of their own barcode to the products which they offer for sale. Many instruments, devices, printers, and the like are currently available for the printing of barcode labels which can readily be applied, one by one, to individual products or to their packaging.
In the instance where a manufacturer or a distributor of a given product purchases the product in large quantities and thereafter sells or distributes the product to a large number of individual retail sellers, heretofore, the manufacturer or distributor often was forced to print out many different UPC codes (one for each of its customers) as labels and physically attach a label to each product. This process economically burdensome, especially from the aspect of the labor cost involved. This procedure is particularly applicable to those "middle man" distributors who purchase large quantities of a given product in bulk and thereafter either package or otherwise prepare each of the products for distribution to retailers of the product.
One example of products which are distributed and sold at retail are "flat goods" such as floor mats for automobiles. Bed sheets and other products also are at times sold as "flat goods". In the instance of automobile floor mats, a distributor (or the manufacturer itself) will employ a "header" or "header card" which serves the purposes of identifying the goods plus hanging the goods vertically for space-saving display in a retail outlet. Header cards commonly take the form of an individual sheet of paperboard which is folded about its transverse centerline and fitted over, and secured to, the top edge of the flat good (e.g. a floor mat). Commonly the header is hole-punched for hanging on a rack or the like. For a large quantity of a given flat good, a common header card is commonly printed and attached to the flat good. However, either the manufacturer or the distributor is called upon to apply a proper UPC barcode to each item of the flat goods to accommodate each of their individual buyers, who in turn, sell the product at retail. In the industry, this practice of printed and attaching individual UPC barcodes to header cards has been carried out by the manufacturer or distributor, irrespective of the quantity purchased by a given retailer, all as a matter of gaining sales. Such practice obviously is costly to the manufacturer or distributor in that the known prior art does not provide a system or device for continuously printing UPC barcode information on a selected number of header cards which have previously been printed with product graphics, etc. Rather, in the prior art the header cards were printable only on a one-by-one intermittent basis. That is, the header card being printed with barcode information had to be fed to a printer head and the forward motion of the header card halted while printing took place. In like manner, where thermal printing was employed, halting of forward movement of the header card at a "curing station" also was required. Control over the movement of such header cards and timing of the printing and curing were all sources of problems in such printing devices and systems.

Sheet fed continuous motion printing system


A radio device includes an array antenna including a plurality of antennas; an adaptive array processing unit multiplying signals provided from the respective antennas of the array antenna by receive weights, and thereby extracting a signal received from desired another radio device; a switch circuit provided corresponding to at least one of the plurality of antennas for providing the signal received from the corresponding antenna to the reception signal processing unit in a receive operation; and a transmission amplifier amplifying and providing a modulated transmission signal to the first switch circuit corresponding to the one of the plurality of antennas.

In recent years, mobile communication systems such as a PHS (Personal Handy phone System) have been rapidly developed, and these systems have employed a TDMA method, in which one frame (5 milliseconds) formed of four slots (625 microseconds per slot) is used as a basic unit for transmission and reception. This TDMA method of the PHS has been standardized, e.g., as a "second generation cordless communication system).
In the communication system of the PHS, a signal in one frame is divided into eight slots, which are divided into a first half including four slots for reception as well as a latter half including four slots for transmission.
Each slot is formed of 120 symbols. For example, the signal in one frame is handled such that three slot sets each formed of one reception slot and one transmission slot are allocated to traffic channels for three users, respectively, and remaining one set of slots is allocated to a control channel.
According to controlling procedures for establishing synchronization in the PHS, a link channel is first established by a control channel, and processing of measuring interference wave (U-waves: Undesired waves) is performed. Further processing is performed to set communication conditions with allocated channels, and thereafter, the speech communication starts. The above procedures are disclosed in detail by standards of the PHS, and particularly by the second generation cordless communication system standards RCR STD-28 issued by Association of Radio Industries and Businesses.
FIG. 21 illustrates a communication sequence flow of the PHS. Referring to FIG. 21, this flow will now be briefly described.
By using a C-channel (Control channel: CCH), a link channel establishment request signal (LCH establishment request signal) is sent from a PHS terminal to a base station. The PHS base station detects an empty channel (i.e., empty traffic channel (empty T-channel)), and sends a link channel allocation signal (LCH allocation signal) to the PHS terminal side via the C-channel.
On the PHS terminal side, it is determined based on link channel information received from the PHS base station whether interference wave signals of a predetermined power or higher are received or not on a designated T-channel, and thus U-wave measurement and carrier sense are performed. When interference wave signals of the predetermined power or higher are not detected, i.e., when another PHS base station is not using the designated T-channel, a synchronous burst signal is sent to the base station by the designated T-channel, and a synchronous burst signal is also returned from the base station to the terminal to establish the synchronization.
When interference wave signals of the predetermined power or higher are detected on the designated T-channel, i.e., when another PHS base station is using the designated T-channel, the PHS terminal repeats the control procedures starting from issuance of the request signal for the link channel establishment.
As described above, the PHS connects the communication channel between the terminal and the base station by using the channel, which can provide good communication characteristics suppressing the interference waves.
For maintaining a good communication quality by suppressing an influence by communication of another base station, the PHS may perform transmission and reception with directivity when the base station transmits a signal to the terminal or receives a signal therefrom.
In the PHS and others, a PDMA (Path Division Multiple Access) system is available for increasing an efficiency of use of wave frequencies. In the PDMA, spatial multiple connection can be achieved between mobile radio terminal devices (terminals) of a plurality of users and the radio base station (base station) via a plurality of paths, which are formed by spatially dividing the same time slot of the same frequency.
For example, an adaptive array technology has been employed for achieving the directivity in the transmission and reception and achieving the PDMA system described above. The adaptive array processing can accurately extracts signals from a desired terminal by adaptive control, which is performed by calculating a weight vector (receive weight vector) formed of receive coefficients (weights) for respective antennas of the base station based on the signal received from the terminal, and thus, by multiplying the reception signals of the plurality of antennas by respective elements of the receive weight vector.
By the adaptive array processing, an uplink signal sent from the antenna of each user terminal is received by the array antenna of the base station, and the signal thus received is separated and extracted with a receive directivity.
The transmission signals (i.e., signals to be sent) are processed such that signals, which are produced by multiplying the transmission signal by respective elements of the transmission weight vector calculated from the receive weight vector, are transmitted from the plurality of antennas, and thereby a downlink signal to be sent from the base station to the terminal is transmitted with a send directivity with respect to the antenna of the terminal.
The above adaptive array processing is well known, and is specifically disclosed in Nobuyoshi Kikuma "Chapter 3: MMSE Adaptive Array" in "Adaptive Signal Processing by Array Antenna", Kagaku Gijutsu Shuppan, Nov. 25, 1998, pp. 35–49. Therefore, an operation principle thereof is not described in this specification.
Among the signals received in the PDMA system, a desired signal is identified in the following manner. A radio signal transmitted between a terminal such as a cellular phone and a base station is divided into a plurality of frames, and thus has a so-called frame structure when it is transmitted. Each frame includes eight slots formed of, e.g., four slots for uplink communication and four slots for downlink communication. This slot signal is basically formed of a preamble formed of a signal series, which is known on a receiver side, and data (such as voice) formed of a signal series, which is unknown on the receiver side.
The preamble signal series includes a signal series (reference signal such as a unique word signal) of information for determining whether the sender on the other end is the desired party for the receiver side or not. For example, the adaptive array radio base station performs weight vector control (determination of weight coefficients) to extract a signal, which is presumed to include a signal series corresponding to the desired party on the other end, based on a comparison between the unique word signal obtained from the memory and the received signal series.
Further, each frame includes the foregoing unique word signal (reference signal) section, and is further configured to allow error detection with cyclic codes (CRC: Cyclic Redundancy Check).
FIG. 22 is a conceptual view illustrating a state of communication between a conventional radio device and a base station.
In an example illustrated in FIG. 22, the communication is being performed between a radio base station CS1 and a radio terminal device PS1, and the communication is also being performed between another radio base station CS2 neighboring to radio base station CS1 and another radio terminal device PS2.
In FIG. 22, it is assumed that non-directional transmission and reception is performed for both the communication from the radio terminal device to the base station, which will be referred to as "uplink communication" hereinafter, and the communication from the radio base station to the radio terminal device, which will be referred to as "downlink communication" hereinafter.
In the structure illustrated in FIG. 22, a problem of interference is liable to occur when the communication in a peripheral cell, which is a communication region of radio base station CS2, is being performed with the same frequency and at the same time as the communication in a cell, which is a communication region of radio base station CS1.
More specifically, in the uplink communication, the quality of the uplink communication in the station's own cell is impaired by the interference from the peripheral cell.
Likewise, in the downlink communication, the interference is applied to the peripheral cell to impair the downlink quality of the terminal, which is communicating in the peripheral cell.
In FIG. 22, arrows with dotted lines indicate interference signals occurring between radio base station CS1 and radio terminal device PS2.
For suppressing the interference during the simultaneous communication with the same frequency, the adaptive array transmission and reception already described may be performed.
However, if the adaptive array transmission and reception is performed in both the uplink communication and the downlink communication, this increases an installation cost of the base station.
More specifically, for performing the adaptive array processing in the downlink communication, an expensive high-power amplifier is required for every antenna of the base station, resulting in the high installation cost.
Further, each base station requires a signal processing circuit for controlling the downlink directivity, which further increases the cost.
If the FDD (Frequency Division Duplex) system is employed, it is difficult to control accurately the directivity.
In other words, a difference occurs in amount of rotation of a phase, which is caused when passing through a propagation path, between the uplink communication and the downlink communication. Therefore, it is difficult to control the directivity in the downlink communication based on information related to the directivity obtained in the uplink communication so that accurate control of the directivity is difficult, and interference with the peripheral cell increases.
The invention has been developed for overcoming the above problems, and it is an object of the invention to provide a radio device, a transmission and reception directivity control method and a transmission and reception directivity control program, which can reduce an installation cost of the base station, and can suppress interference signals affecting a peripheral cell.

Radio device, transmission/reception directivity control method, and transmission/reception directivity control program


A method and apparatus for applying an electronic component adhesive with a minimum length of time for setting a proper application condition. Variation of application shapes of each type of the adhesive is monitored under various different application conditions and its resultant data is saved. When a desired application shape is inputted, the application nozzles are automatically controlled to apply desired doses of the adhesive under an optimum application condition which is defined by retrieving the data previously stored. Also, various different application shapes for bonding respective electronic components may be determined and saved in advance, so that a proper application condition can be automatically determined by retrieving the data on the application shapes when a desired electronic component is selected.

1. Technical Field of the Invention
The present invention relates to a method of and an apparatus for applying an electronic component adhesive, and more particularly to a method and apparatus for intermittently applying desired doses of an electronic component adhesive in a spot-like form.
2. Description of Related Art
A conventional apparatus for applying an electronic component adhesive in desired spot shapes with intermittently actuated application nozzles comprises a plurality of application nozzles, a monitor camera, and a positioning table for locating a printed circuit board onto which doses of the adhesive are applied.
When various data on application conditions such as application points, discharging pressure of the nozzles, and discharging duration of the same is inputted to a controller of the apparatus, the controller drives the positioning table and the application nozzles to set the printed circuit board at a predetermined position and apply spots of the desired shape of the adhesive onto the printed circuit board.
However, in the above-described conventional apparatus, the various data on application conditions, e.g. discharging pressure and duration of the nozzles needs to be entered only after reviewed with the monitor camera to confirm, before the actual application, that the size or diameter of the spot shape is adequate for bonding desired electronic components. This process will take a considerable length of time and create an extra job for an operator.

Method and apparatus for applying an electronic component adhesive

Matsushita Electric Industrial Co., Ltd.


Methods and apparatus provide for loading at least one software program module from a storage medium into a local memory of a processor for execution, the storage medium containing a main module and a plurality of sub-modules of the software program; and updating an address table, copies of the address table being located in at least one of the storage medium and the local memory, and the address table having at least one entry for each of the modules, each entry including at least one of: (i) a destination address representing an address within the local memory of a processor at which the corresponding module is disposed, and (ii) a source address representing an address within the storage medium at which the corresponding module originates.

The present invention relates to methods and apparatus for transferring data within a multi-processing system.
In recent years, there has been an insatiable desire for faster computer processing data throughputs because cutting-edge computer applications involve real-time, multimedia functionality. Graphics applications are among those that place the highest demands on a processing system because they require such vast numbers of data accesses, data computations, and data manipulations in relatively short periods of time to achieve desirable visual results. These applications require extremely fast processing speeds, such as many thousands of megabits of data per second. While some processing systems employ a single processor to achieve fast processing speeds, others are implemented utilizing multi-processor architectures. In multi-processor systems, a plurality of sub-processors can operate in parallel (or at least in concert) to achieve desired processing results.
In some processing systems a processor may employ a relatively small local memory in which to execute program code (as opposed to a larger random access memory, RAM). The larger RAM (main or system memory) may be used for bulk storage. The processor may also employ direct memory access (DMA) technology to transfer data from the main memory to the local memory. Data streaming may be employed to feed data (such as video data) from the main memory into the local memory for data manipulation. Application programs, however, cannot be fed into the local memory using data streaming techniques.

Methods and apparatus for dynamic linking program overlay


A support foot (10) for applying and distributing forces to a pressure-sensitive substrate, including a baseplate (12) for placement onto the substrate and a holder (18) which is joined to the baseplate (12) and to which the connecting parts (32, 72) can be attached, whereby the holder (18) has a first receptacle (20) for a first connecting part (72) and a second receptacle (22) for a second connecting part (32). A stand system has at least one support foot (10) and at least one, especially C-shaped, mounting rail that is inserted into a receptacle (20, 22, 24) and that is prevented by a fastener (56) from being pulled out of the holder (18).

Stand systems having such support feet are, for example, installations on stands mounted on flat roofs, such as ventilation conduits or ventilation aggregates, air-conditioning systems, pipelines or ductwork. Since flat roofs often have pressure-sensitive sealing films or bitumen sheeting, there is a need to distribute the support load by means of appropriate support feet. Other applications for stand systems having support feet are scaffolding or temporary installations such as bleachers, whereby here, the load is applied to an asphalt surface or to a ground surface.
European patent EP 2 228 501 B1 discloses a support foot of the generic type, which has a base part as well as a sliding part that can be moved at a slant relative to the base part by a few degrees in an axial direction, whereby a vertically oriented mounting rail can be attached to said sliding part. A separate replaceable sliding part is provided so that a horizontally oriented rail can be attached.

Support foot for applying and distributing forces to a pressure-sensitive substrate as well as a stand system having such a support foot


According to one embodiment, a ceramic copper circuit board a ceramic substrate, a copper circuit board provided at one surface of the ceramic substrate. A ratio of a thickness of the copper circuit board to a thickness of the ceramic substrate is 1.25 or more. A number of grain boundaries is not less than 5 and not more than 250 along every 10-mm straight line drawn in a front surface of the copper circuit board.

A ceramic copper circuit board is used in a semiconductor device in which a semiconductor element such as a power element or the like is mounted. The ceramic substrate and the copper circuit board are bonded via a bonding layer. A Ag brazing material that includes a reactive metal such as Ti or the like is used as the bonding layer. The bonding strength and the heat cycle characteristics are improved thereby. Due to the increase of the reliability of ceramic copper circuit boards, ceramic copper circuit boards are used favorably in inverters of automobiles (also including electric cars), electric railway vehicles, solar power generation equipment, and industrial machinery.
In a semiconductor device such as a power module or the like, a semiconductor element is mounted on the copper circuit board. Also, wire bonding and/or a metal terminal may be bonded to the copper circuit board for the conduction of the semiconductor element. The semiconductor element, the wire bonding, the metal terminal, etc., are bonded to the copper circuit board to complete the semiconductor device.
International publication WO2013-094213 (Patent Literature 1) describes a ceramic copper circuit board in which the reliability is increased. In Patent Literature 1, the reliability is increased by optimizing the side surface configuration of the copper circuit board. The bonding strength and the heat cycle resistance of the ceramic copper circuit board of Patent Literature 1 are improved.
On the other hand, there is still room for improvement to increase the reliability of the assembly process in which the semiconductor element, the wire bonding, the metal terminal, etc., are bonded to the copper circuit board.

Ceramic copper circuit board and semiconductor device based on the same


There is provided a method of fabricating a semiconductor device having plural light receiving elements, and having an amplifying element, the method including: a) forming an active region on the semiconductor substrate for configuring the amplifying element; b) forming a light receiving element region on the semiconductor substrate for forming the plural light receiving elements, with the active region acting as a reference for positioning; c) implanting an impurity into the light receiving element region; d) repeating the process b) and the process c) a number of times that equals a number of diffusion layers in the light receiving element region; e) after implanting the impurity, performing a drive-in process to carry out drive in of the semiconductor substrate; and f) the process e), forming an amplifying element forming process by implanting an impurity in the active region.

1. Technical Field
The present invention relates to a method of fabricating a semiconductor device provided with two or more types of light receiving element.
2. Related Art
Conventionally, semiconductor devices provided with light receiving elements, for example illumination sensors, image sensors, or the like, are configured, for example, with two or more types of photodiode (light receiving element) formed in a silicon substrate.
For example, for an SOI substrate having a semiconductor layer formed on a semiconductor substrate with an insulating layer interposed therebetween, a method is disclosed in Japanese Patent Application Laid-Open (JP-A) No. 2006-24787 of removing the insulating layer and the semiconductor layer to expose a portion of the semiconductor substrate, forming a well in the exposed semiconductor substrate for forming a photodiode, and then forming a transistor in the semiconductor layer.
Also, in JP-A No. 2006-245246, there is a proposal to configure two or more types of photodiode such that they each have a different junction depth. In this proposal, sensitivity is imparted to light of comparatively shorter wavelengths as the junction depth gets shallower, and sensitivity is imparted to light of shorter comparative wavelengths when the junction is formed deeper. By detecting the photoelectric current from such photodiodes having sensitivity to different wavelengths, and by computation with a computation circuit, a photodiode is formed that suppresses sensitivity to the infrared wavelength region.
However, an extremely complicated structure arises when two or more types of photodiode (light receiving element) are formed in a silicon substrate, and there is a greater number of fabrication processes.

Method of fabricating semiconductor device


A system and method to improve the high voltage performance of an x-ray tube with electrostatic deflection of an electron beam focal spot. The system and method provides protection of bias circuits from high voltage transients and spit protection in x-ray tubes through the use of a high voltage transient suppression and spit protection circuit assembly coupled between the bias circuits of a high voltage generator and an x-ray tube vacuum housing of an x-ray generation system.

This disclosure relates generally to x-ray generation systems. In particular, this disclosure relates to systems and methods for protection of bias circuits from high voltage transients and discharge/spit protection in x-ray tubes.
An x-ray tube generally includes a cathode assembly and an anode assembly disposed within a vacuum vessel. The anode assembly includes an anode having a target track or impact zone that is generally fabricated from a refractory metal with a high atomic number, such as tungsten or a tungsten alloy. The anode is commonly a rotating disk. The cathode assembly is positioned at some distance from the anode assembly creating a vacuum gap between the cathode assembly and the anode assembly, and a high voltage potential difference is maintained therebetween. The cathode assembly emits electrons in the form of an electron beam that are accelerated across the potential difference and impact the target track at a focal spot of the anode at a high velocity. As the electrons impact the target track, the kinetic energy of the electrons is converted to high-energy electromagnetic radiation, or x-rays. The x-rays are then transmitted through an object such as the body of a patient and are intercepted by a detector that forms an image of the objects internal anatomy.
In an x-ray tube, the focal spot can be controlled and deflected electrostatically through bias voltages. This is accomplished by applying different bias voltages at a number of electrodes within the cathode assembly. The cathode assembly generally includes at least two pairs of electrodes positioned on opposite sides of the cathode filament to control the size and deflection of the electron beam. A bias voltage is independently applied to each of the electrodes to focus and/or deflect the electron beam. In an x-ray tube with focal spot wobbling, the focal spot is wobbled electrostatically between two positions on a target track of an anode during a scan sequence. Electrically isolating the cathode septum and applying a continuously varying bias voltage to the cathode filament provides two unique focal spots that can be controlled with bias voltages. It is generally preferable to minimize the bias voltages at the electrodes to reduce the risk of insulation breakdown and improve reliability of the x-ray tube.
One of the potential problems in an x-ray tube is that there are considerable high voltage transients induced across the bias circuits, resulting in possible damage of the high voltage cable assembly and certain components within the high voltage generator, when a spit (either a vacuum discharge or a vacuum arc) occurs. A typical high voltage transient within the bias circuits could be as high as several tens of kilovolts for an x-ray tube. This presents a serious reliability problem, as the basic insulation level for the minor insulation along the bias circuits is not high enough to withstand these high voltage transients.
Therefore, there is a need for a system and method that prevents the occurrence of high voltage transients within an x-ray tube, and in particular provides protection of bias circuits from high voltage transients and spit protection in x-ray tubes.

System and method for high voltage transient suppression and spit protection in an x-ray tube


A corrosion protection system is provided. The corrosion protection system comprises an electrical contact coupled to an apparatus. The electrical contact can apply a negative potential to the apparatus. The corrosion protection system comprises a sensor. The sensor detects moisture with respect to the apparatus. The corrosion protection system comprises a power supply. The power supply is electrically coupled to the electrical contact and provides a negative potential to the electrical contact in accordance with commands of a processor. The processor utilizes the power supply attached to the apparatus via the electrical contact to provide and apply the negative potential to the apparatus based on a sensor signal from the sensor. The sensor signal indicates the detection of the moisture by the sensor.

Generally, corrosion is a degradation of metal caused by a reaction with an environment, such as an oxidation of and/or a chemical attack on a material surface of the metal. Copper, for example, is susceptible to attack from sulfur-containing gases. The reaction with the environment can also cause formations of nonprotective layers on the material surface. Further, unprotected metals continue to react with contaminants and corrode. When left unchecked and under prolonged conditions, continuous corrosion can jeopardize the integrity of the metal.
Accordingly, there exists a need for a corrosion protection system that can monitor, detect, address, and/or prevent corrosion.

Corrosion protection system for heating ventalation air conditioning refrigeration


A method for producing an atomized powder of chromium carbide particles dispersed in a nickel chromium matrix in which chromium in the powder is from 55 to 92 weight percent of the powder.

Atomization technology is the breakup of a liquid into small droplets, usually in a high-speed jet or film. The production of high-quality powders, such as aluminum, brass, nickel alloys, cobalt alloys, wear resistant steel, and the like have been produced using the atomization technology. As simply defined, atomization is the breakup of a liquid to form droplets, typically smaller than about 150 .mu.m. The breakup of a liquid stream brought about by the impingement of high-pressure jets of water or gas is referred to as water or gas atomization, respectively. The use of centrifugal force to break up a liquid stream is known as centrifugal atomization; the use of vacuum is known as vacuum atomization and the use of ultrasonic energy to effect breakup of a liquid stream is referred to as ultrasonic atomization. By regulating the parameters of the atomization process, the particle size, particle size distribution, particle shape, chemical composition and microstructure of the particles can be varied.
Conventional water and gas atomization processes presently account for the bulk of atomized metal powders. Water-atomized powders generally are quite irregular in shape and have relatively high surface oxygen contents. Gas-atomized powders, on the other hand, generally are more spherical or rounded in shape and, if atomized by an inert gas, generally have lower oxygen (oxide) contents. The major components of a typical atomization installation include a melting facility, an atomizing chamber, and powder drying (for water atomization) equipment. Melting of metals follows standard procedures. Air, inert gas and vacuum induction melting, arc melting, and fuel heating are suitable procedures.
The molten metal can be poured into a tundish, which is essentially a reservoir that supplies a uniform and controlled flow of molten metal to the tundish nozzle. The nozzle, which can be located at the base of the tundish, controls the shape and size of the metal stream and directs it through an atomizing nozzle system in which the metal stream is disintegrated into fine droplets by the high-velocity atomizing medium. Liquid droplets cool and solidify as they settle to the bottom of the atomization tank. This tank may be purged with an inert gas to minimize or prevent oxidation of the powder. In gas atomization, the powder may be collected as dry particles or cooled with water at the bottom of a tank. In dry collection, the atomization tank could be tall to ensure solidification of the powder particles before they reach the bottom of the collection chamber. Horizontal gas atomization using long horizontal tanks could also be used.
There are various types of gas and water nozzles known in the art to control the parameters of the atomization process to produce a desired powder product.
It is disclosed in the art that typical metal flow rates through single orifice nozzles could range from about 10 to 200 lb/min; typical water flow rates range from 30 to 100 gal/min at water velocities ranging from 230 to 750 ft/s and pressures from 800 to 3000 psi. Typical gas flow rates range from 40 to 1500 scfm at gas pressures in the range of 50 to 1200 psi. Gas velocities depend on nozzle design and may range from 60 ft/s to supersonic velocities. The temperature differential between the melting point of the metal and the temperature at which the molten metal is atomized (superheat of the molten metal) is generally about 75.degree. to 300.degree. C. (135.degree. to 572.degree. F.). There are many other variations to the atomization process known in the art to produce powder products.
U.S. Pat. No. 5,126,104 discloses a method for preparing an intimate mixture of powders of nickel-chromium-boron-silicon alloy, molybdenum metal powder, and Cr.sub.3 C.sub.2 /NiCr alloy suitable for thermal spray coatings which comprises milling a starting mixture of the above two alloys with molybdenum powder to produce a milled mixture wherein the average particle size is less than about 10 micrometers in diameter, forming an aqueous slurry of the resulting milled mixture and a binder which can be an ammoniacal molybdate compound or polyvinyl alcohol, and agglomerating the milled mixture and binder. The intimate mixture and binder may be sintered in a reducing atmosphere at a temperature of about 800.degree. C. to 950.degree. C. for a sufficient time to form a sintered, partially alloyed mixture wherein the bulk density is greater than about 1.2 g/cc. The resulting sintered mixture may be entrained in an inert carrier gas, passed into a plasma flame wherein the plasma gas can be argon or a mixture of argon and hydrogen, and maintained in the plasma flame for a sufficient time to melt essentially all of the powder particles of the sintered mixture to form spherical particles of the melted portion and to further alloy the sintered mixture, and cooled.
U.S. Pat. No. 3,846,084 discloses a composite powder for use in producing articles or coatings having unique wear and frictional characteristics consisting essentially of a chromium matrix with at least one chromium carbide taken from the class of carbides consisting of Cr.sub.23 C.sub.8 ; Cr.sub.7 C.sub.3 ; and Cr.sub.3 C.sub.2 and each particle containing from about 0.2 wt. percent to about 5.4 wt. percent carbon.
U.S. Pat. No. 4,725,508 discloses the use of chromium carbide (Cr.sub.3 C.sub.2) powder for use in thermal spray processes. Many of the chromium carbide powders are produced using the sintering techniques known in the prior art.
Although the atomization process has been known since 1945, it was not appreciated that this process could be used to produce a powder that contained a large volume fraction of chromium carbide phases.
It is an object of this invention to produce an atomized powder of chromium carbide particles dispersed in a nickel chromium matrix.
It is another object of this invention to produce powders using low cost raw materials and minimum process steps.
It is another object of the invention to produce an atomized powder of chromium carbide particles dispersed in a nickel chromium matrix in which the chromium is in an amount in weight percent of the powder from 55 to 91; the nickel in an amount in weight percent of 5 to 40 of the powder; and carbon in an amount in weight percent of 1 to 10 of the powder.

Method for producing a chromium carbide-nickel chromium atomized powder


CMP of integrated circuits containing DRAM arrays with trench capacitors fill the trenches with oxide, resulting in a an array of oxide structures that is dense compared with the concentration in the surrounding support structures and therefore has a higher loading. A conformal layer is deposited over the wafer, increasing the loading in the array, but filling in spaces between active areas. A blanket etch removes material in both the array and the supports. A block etch balances the amount of material in the array and the supports. A supplementary oxide deposition in the array fills spaces between the structures to a nearly uniform density.

CMP is a popular technique in contemporary integrated circuit processing, for a number of reasons including reduced depth of field in lithography and reduced tolerances in etching. Those skilled in the art are aware of a recurring problem in CMP—that of polishing surfaces that are not uniform.
The polishing rate depends on the loading—the amount of material to be removed per unit area. A solid area will polish more slowly than a sparsely populated area that has projecting areas to be polished on only a small fraction of the total area. The problem is that the sparsely populated areas can be overpolished, resulting to damage to the layer beneath the layer being removed.
An approach that has been used in the art is applying a block etch to the area with the higher loading. This approach often cannot be applied if the topography in the higher loaded area is such that a block etch would damage the structure below the layer being polished.
This problem becomes more acute as layers become thinner and as tolerances become smaller.

Infineon Technologies North America Corporation


A method for manufacturing a semiconductor device includes: forming a semiconductor element having an electrode on a main surface of a semiconductor substrate; forming a first resin film that encloses a side of the electrode while keeping a distance from the electrode of the semiconductor element on the main surface of the semiconductor substrate; and forming a hollow structure around the electrode of the semiconductor element by bonding a second resin film that covers over the electrode while keeping a distance from the electrode of the semiconductor element to a top surface of the first resin film.

Field of the Invention
The present invention relates to a method for manufacturing a semiconductor device including a hollow structure around a semiconductor element.
Background Art
Multilayer wiring structures in which resin films and metal wires are repeatedly laminated on one another are used to achieve high integration and downsizing of semiconductor devices. However, the resin films cause parasitic capacitance to increase and cause electric characteristics of the semiconductor devices to deteriorate. In semiconductor devices including Y-type or T-type gate electrodes in particular, space under an overhang of the gate electrode is filled with resin, which increases the parasitic capacitance and causes the high-frequency gain to deteriorate (e.g., see T. Hisaka (1), H. Sasaki (1), T. Katoh (1), K. Kanaya (1), N. Yoshida (1), A. A. Villanueva (2), and J. A. del Alamo (2), IEICE Electronics Express, Vol. 7, No. 8, P. 558-562, (1) Mitsubishi Electric Corporation, (2) Massachusetts Institute of Technology).
In contrast, a method is proposed for forming a hollow structure around a semiconductor element by forming a sacrificial layer and a protective film on a semiconductor element and then removing the sacrificial layer (e.g., see Japanese Patent Application Laid-Open No. 2010-205837 and Japanese Patent Application Laid-Open No. 2011-049303).
Another method is proposed for forming a hollow structure between adjacent wires by laminating a sheet film on a substrate on which a plurality of wires are formed (e.g., see Japanese Patent Application Laid-Open No. 2003-142578). However, since there is no semiconductor element between wires, this method has nothing to do with a semiconductor device including a hollow structure around the semiconductor element.

Method for manufacturing a semiconductor device including a hollow structure around an electrode of a semiconductor element


A terminal apparatus configures transmission timing for a PUSCH in a target cell based on first information included in a handover command received. The terminal apparatus initiates a random access procedure in a primary cell, at least in a case that an SR is pending, a UL-SCH resource is not available for transmission in a current subframe, and a valid PUCCH resource for the SR is not available in any one of subframes. The terminal apparatus does not initiate the random access procedure in the primary cell, in the case that the SR is pending, the UL-SCH resource is not available for the transmission in the current subframe, and the valid PUCCH resource for the SR is not available in any one of the subframes, and at least in a case that the first information is configured.

A radio access method and a radio network for cellular mobile communications (hereinafter, referred to as "Long Term Evolution (LTE: Registered Trademark)", or "Evolved Universal Terrestrial Radio Access (EUTRA)") have been studied in the 3rd Generation Partnership Project (3GPP) (NPL 1, 2, 3, 4, and 5). In LTE, a base station apparatus is also referred to as an evolved NodeB (eNodeB), and a terminal apparatus is also referred to as a User Equipment (UE). LTE is a cellular communication system in which multiple areas are deployed in a cellular structure, with each of the multiple areas being covered by a base station apparatus. A single base station apparatus may manage multiple cells.
In order to reduce handover delay, (i) handover by a terminal apparatus from a source cell to a target cell without performing a random access procedure, and (ii) pre-assignment of an uplink grant for transmission of a handover command response (RRC Connection Reconfiguration Complete message) by a handover command have been considered (NPL 6).

Terminal apparatus, base station apparatus, and communication method reducing handover delay


A method and apparatus for providing new configurations for transmitting control information between a mobile terminal and a network using a common control channel (CCCH) logical channel/transport channel. The new configurations enable messages to be sent that are larger than currently allowed and the availability of the new configurations is indicated such that mobile terminals that do not support the new configurations are not impacted.

1. Field of the Invention
The present invention relates to a method and apparatus for enhancing the signaling between a mobile communication device and a network. Specifically, the present invention is directed to a method and apparatus for providing new configurations for transmitting control information between a mobile terminal, for example user equipment (UE), and a radio network controller (RNC) using a common control channel (CCCH) logical channel/transport channel.
2. Discussion of the Related Art
The universal mobile telecommunications system (UMTS) is a European-type, third generation IMT-2000 mobile communication system that has evolved from a European standard known as Global System for Mobile communications (GSM). UMTS is intended to provide an improved mobile communication service based upon a GSM core network and wideband code division multiple access (W-CDMA) wireless connection technology.
In December 1998, the ETSI of Europe, the ARIB/TTC of Japan, the T1 of the United States, and the TTA of Korea formed a Third Generation Partnership Project (3GPP). The 3GPP creates detailed specifications of UMTS technology.
In order to achieve rapid and efficient technical development of the UMTS, five technical specification groups (TSG) have been created within the 3GPP for standardizing the UMTS by considering the independent nature of the network elements and their operations. Each TSG develops, approves, and manages the standard specification within a related region. Among these groups, the radio access network (RAN) group (TSG-RAN) develops the standards for the functions, requirements, and interface of the UMTS terrestrial radio access network (UTRAN), which is a new radio access network for supporting W-CDMA access technology in the UMTS.
A conventional UMTS network structure 1 is illustrated in FIG. 1. One mobile terminal 2, or user equipment (UE), is connected to a core network 4 through a UMTS terrestrial radio access network (UTRAN) 6. The UTRAN 6 configures, maintains, and manages a radio access bearer for communications between the UE 2 and core network 4 to meet end-to-end quality-of-service requirements.
The UTRAN 6 consists of at least one radio network subsystem 8, including one RNC 10 acting as an access point to the core network 4, and at least one Node B 12 managed by a corresponding RNC. The RNCs 10 are logically classified as controlling RNCs, which allocate and manage common radio resources for a plurality of UEs 2 of a cell, and serving RNCs, which allocate and manage dedicated radio resources for a specific UE 2 of a cell. Each Node B 12 manages at least one cell.
The core network 4 may be divided according to the type of service provided, namely, a circuit-switched (CS) domain and a packet-switched (PS) domain. For example, a general voice conversation service is a circuit switched (CS) service, while a Web browsing service via an Internet connection is classified as a packet switched (PS) service.
The CS domain includes a mobile switching center (MSC) 14 acting as an access point to the UTRAN 6 and a gateway mobile switching center (GMSC) 16 acting as an access point to an external network. The PS domain includes a serving GPRS support node (SGSN) 18 acting as an access point to the UTRAN 6 and a gateway GPRS support node (GGSN) 20 acting as an access point to the external network. A visitor location register (VLR) 22 and a home location register (HLR) 24 manage user registration information.
In the CS domain, the access point of the core network 4 is the MSC 14 via an lu-CS interface. For supporting circuit switched services, the RNCs 10 are connected to the MSC 14 of the core network 4 and the MSC is connected to the GMSC 16 that manages the connection with other networks.
In the PS domain, the access point of the core network 4 is the SGSN 18 via an lu-PS interface. For supporting packet switched services, the RNCs 10 are connected to the SGSN 18 and the GGSN 20 of the core network 4. The SGSN 18 supports the packet communications with the RNCs 10 and the GGSN 20 manages the connection with other packet switched networks, such as the Internet.
The interface between the UE 2 and UTRAN 6 is realized through a radio interface protocol established in accordance with 3GPP radio access network specifications. The conventional architecture of the radio interface protocol is illustrated in FIG. 2.
As illustrated in FIG. 2, the conventional radio interface protocol has horizontal layers comprising a physical layer (L1), a data link layer (L2), and a network layer (L3), and has vertical planes comprising a user plane (U-plane) for transmitting user data and a control plane (C-plane) for transmitting control information. The user plane is a region that handles traffic information with the user, such as voice or Internet protocol (IP) packets. The control plane is a region that handles control information for an interface with a network and maintenance and management of a call.
The protocol layers may be divided into a first layer (L1), a second layer (L2), and a third layer (L3) based on the three lower layers of an open system interconnection (OSI) standard model. The first layer (L1) is the physical layer. The second layer (L2) includes a medium access control (MAC) layer, a radio link control (RLC) layer, a broadcast/multicast control (BMC) layer, and a packet data convergence protocol (PDCP) layer.
The physical (PHY) layer provides information transfer service to a higher layer by using various radio transfer techniques. The physical layer is linked via transport channels to a medium access control (MAC) layer.
The MAC layer handles mapping between logical channels and transport channels and provides allocation of the MAC parameters for allocation and re-allocation of radio resources. The MAC layer is connected to the physical layer by transport channels and may be divided into a MAC-b sub-layer, a MAC-d sub-layer, a MAC-c/sh sub-layer, and a MAC-hs sub-layer according to the type of transport channel being managed.
The MAC layer is connected to an upper layer called the radio link control (RLC) layer, via a logical channel. Various logical channels are provided according to the type of information transmitted. In general, a control channel is used to transmit information of the control plane and a traffic channel is used to transmit information of the user plane.
A logical channel may be a common channel or a dedicated channel depending on whether the logical channel is shared. Logical channels include a dedicated traffic channel (DTCH), a dedicated control channel (DCCH), a common traffic channel (CTCH), a common control channel (CCCH), a broadcast control channel (BCCH), and a paging control channel (PCCH), or a Shared Channel Control Channel. The BCCH provides information including information utilized by a UE 2 to access the core network 4. The PCCH is used by the UTRAN 6 to access a UE 2. The different logical channels are listed in FIG. 3.
The MAC-b sub-layer manages a BCH (Broadcast Channel), which is a transport channel handling the broadcasting of system information. In the downlink, the MAC-c/sh sub-layer manages a common transport channel, such as a forward access channel (FACH) or a downlink shared channel (DSCH), which is shared by a plurality of terminals. In the uplink, the MAC-c/sh sub-layer manages a Radio Access Channel (RACH). Therefore, each UE 2 has one MAC-c/sh entity.
The possible mapping between the logical channels and the transport channels from the perspective of a UE 2 is illustrated in FIG. 4. The possible mapping between the logical channels and the transport channels from the perspective of a UTRAN 6 is illustrated in FIG. 5.
The MAC-d sub-layer manages a dedicated channel (DCH), which is a dedicated transport channel for a UE 2. The MAC-d sublayer is located in a serving RNC 10 (SRNC) that manages a corresponding UE 2, and one MAC-d sublayer also exists in each UE 2.
The RLC layer, depending of the RLC mode of operation, supports reliable data transmissions and performs segmentation and concatenation on a plurality of RLC service data units (SDUs) delivered from an upper layer. When the RLC layer receives the RLC SDUs from the upper layer, the RLC layer adjusts the size of each RLC SDU in an appropriate manner based upon processing capacity and then creates data units by adding header information thereto.
The data units, called protocol data units (PDUs), are transferred to the MAC layer via a logical channel. The RLC layer includes a RLC buffer for storing the RLC SDUs and/or the RLC PDUs. The RLC services are used by service-specific protocol layers on the user plane, namely a broadcast/multicast control (BMC) protocol and a packet data convergence protocol (PDCP), and are used by a radio resource control (RRC) layer for signaling transport on the control plane.
The BMC layer schedules a cell broadcast (CB) message delivered from the core network 4 and enables the CB message to be broadcast to the corresponding UEs 2 in the appropriate cell. Header information, such as a message identifier, a serial number, and a coding scheme, is added to the CB message to generate a BMC message for delivery to the RLC layer.
The RLC layer appends RLC header information and transmits the thus-formed message to the MAC layer via a common traffic channel as a logical channel. The MAC layer maps the common traffic channel to a forward access channel (FACH) as a transport channel. The transport channel is mapped to a secondary common control physical channel as a physical channel.
The PDCP layer is located above the RLC layer. The PDCP layer is used to transmit network protocol data, such as the IPv4 or IPv6, effectively on a radio interface with a relatively small bandwidth. For this purpose, the PDCP layer reduces unnecessary control information used in a wired network, a function called header compression.
The radio resource control (RRC) layer located at the lowest portion of the third layer (L3) is only defined in the control plane. The RRC layer handles the control plane signaling of the network layer (L3) between the UEs 2 and the UTRAN 6 and controls the transport and physical channels for the establishment, reconfiguration, and release of radio bearers. A radio bearer is a service provided by a lower layer, such as the RLC layer or MAC layer, for data transfer between the UE 2 and UTRAN 6.
The air interface (Uu) between the UE 2 and the UTRAN 6 includes the RRC layer for the establishment, reconfiguration, and release of radio bearers, for example a service providing data transfer between the UE and an RNC 10 of the UTRAN. Establishment of a radio bearer determines the regulating characteristics of the protocol layer and channel needed to provide a specific service, thereby establishing the parameters and operational methods of the service.
A UE 2 is said to be in the RRC-connected mode when the RRC layer of a UE and the RRC layer of a corresponding RNC 10 are connected, thereby providing for bi-directional transfer of RRC messages. If there is no RRC connection, the UE 2 is said to be in the RRC-idle mode.
Upon power-up, a UE 2 is in the RRC-idle mode by default. When necessary, an RRC-idle UE 2 transitions to the RRC-connected mode through an RRC connection procedure.
An RRC connection is established, for example, when uplink data transfer is needed to make a call or to respond to a paging message from the RNC 10. The RRC connection connects the UE 2 to the RNC 10 of the UTRAN 6.
The different possibilities that exist for the mapping between the radio bearers and the transport channels are not all possible all the time. The UE 2 and UTRAN 6 deduce the possible mapping depending on the UE state and the procedure that the UE and UTRAN are executing.
The different transport channels are mapped onto different physical channels. For example, the RACH transport channel is mapped on a given PRACH, the DCH may be mapped on the DPCH, the FACH and the PCH may be mapped on the S-CCPCH, and the DSCH is mapped on the PDSCH. The configuration of the physical channels is determined by RRC signaling exchange between the RNC 10 and the UE 2.
Because an RRC connection exists for UEs 2 in RRC connected mode, the UTRAN 6 can determine the existence of a particular UE within the unit of cells, for example in which cell or set of cells the RRC connected mode UE resides, and which physical channel the UE is monitoring. Therefore, the UE 2 can be effectively controlled.
In contrast, the UTRAN 6 cannot determine the existence of a UE 2 in idle mode. The existence of idle UEs 2 can only be determined by the core network 4 to be within a region that is larger than a cell, for example a location or a routing area. Therefore, the existence of idle mode UEs 2 is determined within large regions, and, in order to receive mobile communication services such as voice or data, the idle mode UE must transition into the RRC connected mode. The possible transitions between modes and states are illustrated in FIG. 6.
A UE 2 in RRC connected mode may be in different states, for example CELL_FACH state, CELL_PCH state, CELL_DCH state or URA_PCH state. Depending on the state, the UE 2 performs different actions and monitors different channels.
For example a UE 2 in CELL_DCH state will attempt to monitor, among others, a DCH type of transport channel that is mapped to a certain DPCH. A UE 2 in CELL_FACH state will monitor several FACH transport channels that are mapped to a certain S-CCPCH. A UE 2 in CELL_PCH state will monitor the PICH channel and the PCH channel that is mapped to a certain S-CCPCH physical channel.
The actions of a UE 2 are also different depending on the state. For example a UE 2 is in CELL_FACH state whenever it moves from one cell into another cell and, depending on different conditions, the UE will start the CELL Update procedure by transmitting a Cell Update message to the Node B 12 to indicate that the UE has changed location and will begin monitoring the FACH channel. This procedure is also performed when the UE 2 transitions from any other state to CELL_FACH state and the UE has no C-RNTI available, for example when transitioning from CELL_PCH state or CELL_DCH state, or when a UE in CELL_FACH state was previously out of a coverage area.
In order to distinguish transmissions between the RNC 10 and the different UEs 2 and in order to distinguish the different radio bearers that may be multiplexed in the MAC layer, the MAC includes a header in the transmissions. The logical channel type determines the type of MAC header that the UE 2 uses to transmit the message, the UMTS mode (FDD or TDD) and the transport channel to which the logical channel is mapped. This header may contain an identifier that identifies a specific UE 2.
There are different identifiers used in the MAC header to distinguish transmissions to/from the different UEs 2. The RNC 10 allocates the different identifiers.
Examples of identifiers are C-RNTI, U-RNTI, S-RNTI and H-RNTI. C-RNTI is used to identify a given UE 2 in a given cell. U-RNTI is used to identify a UE 2 in a given UTRAN 6 system. S-RNTI identifies the UE 2 on a DSCH transport channel. H-RNTI identifies the UE 2 on a given HSDPA transport channel.
The fields that are contained in the MAC header for all transport channels except the HS-DSCH transport channel are illustrated in FIG. 7. The TCTF (Target Channel Type Field) field indicates the type of logical channel that is mapped on the given transport channel in the event different logical channels may be mapped on the transport channel. The UE-Id type is the UE 2 identifier. The C/T field indicates the radio bearer that was established.
The TCTF is utilized to distinguish between the different logical channels. Distinguishing between logical channels determines the exact format of the rest of the MAC header. For example, If the CCCH is mapped on RACH/FACH, the MAC header contains only the TCTF field that carries the information that the rest of the MAC PDU contains a message from a CCCH type transport channel.
Presently, the UMTS standard indicates that only the signaling radio bearer 0 (SRB0) may use the CCCH logical channel. Therefore there is no need for the C/T field when the CCCH logical channel is used.
In the uplink, not all transport channels are available depending upon the state of the UE 2. For example when the UE 2 is in CELL_FACH state, the UE cannot use a DCH transport channel, but may use, for example, a RACH transport channel.
For the mapping of DCCH on RACH, for example, the UE 2 must have a valid C-RNTI. However, if the UE 2 has just moved into a new cell and desires to start the Cell Update procedure, the UE does not have a valid C-RNTI. Therefore, the UE 2 may only map the CCCH logical channel on the RACH. In coding the CCCH message, an "initial Identity," which is either fixed or allocated to the UE 2 by the core network 4, or the U-RNTI is included in the message to distinguish the UE 2.
The same situation exists when the UE 2 has just been powered on and wants to establish an RRC connection. Therefore, the UE 2 may only use CCCH logical channel mapped on the RACH transport channel to transmit the RRC Connection Request message.
The RLC layer may use either transparent mode (TM), unacknowledged mode (UM) or acknowledged mode (AM). Depending upon the mode, the size of the RLC PDUs may change after each transmission of a transport block. In TM and UM mode, the size of the RLC PDUs may change after each transmission. In AM, the PDU size may not be changed dynamically, but only through a reconfiguration by the RNC 10, because the PDUs might be retransmitted.
The transport channels may handle RLC PDUs of predefined sizes. The transport block size of the physical layer is defined by the RLC PDU size and the MAC header size. Different transport channels allow different transport block sizes and a given transport channel may also allow different sizes. Generally, the transport block sizes a UE 2 is allowed to use for a specific radio bearer are determined by the RNC 10 or fixed by the UMTS standard.
A transport channel is defined by its type, for example RACH, FACH, DCH, DSCH or USCH, and by its attributes. Some attributes are dynamic and some attributes are semi-static.
Dynamic attributes include the transport block size, which is the size of the MAC PDU; the transport block set size, which is the size of the MAC PDU multiplied by the number of MAC PDUs that can be transported in one transmission time interval (TTI); and the transmission time interval, which is an optional dynamic attribute for TDD only. Semi-static attributes include the transmission time interval, which is mandatory for FDD and optional for the dynamic part of TDD NRT bearers; the error protection scheme applied; the type of error protection; the turbo code; the convolutional code; no channel coding, which is semi-static for TDD only; the coding rate; the static rate matching parameter; and the size of CRC.
The semi static part of an attribute may only be changed when the RRC layer changes the configuration. The dynamic part of an attribute provides several alternatives, for example that there may be one, two or three transport blocks transmitted in one TTI. Furthermore, the transport block size may be changed during each TTI.
A set of values of the dynamic and the semi-static parts is called a transport format (TF). Each transport channel may use one or more transport formats. For example, only one transport channel may be mapped on the Physical Random Access Channel (PRACH), the channel to which the present invention is directed.
The PRACH message includes a data portion that is generated out of the transport block set received by the MAC layer and includes control information that is generated in the Physical layer. The control information includes the transport format combination indicator (TFCI) that is used to determine the coding and the transport format that is used for the transmission. FIG. 8 illustrates the RACH message structure.
When a radio bearer is mapped via a logical channel to a transport channel, not all existing transport format combinations may be used. The allowable transport format combinations are determined by the RRC protocol, as indicated by the RB mapping information.
Presently, the UMTS standard indicates that signaling radio bearer number 0 (SRB0) is always mapped via a CCCH logical channel on the RACH transport channel. Presently, the UMTS standard also indicates that a UE2 is only allowed to use the first transport format that is listed for the selected RACH for transmission of messages via CCCH.
Generally, the first transport format of a RACH may carry only one transport block of 168 bits. However, the messages that are transmitted via the CCCH may be large and, in some situations, it may be beneficial to use also other transport block sizes.
The CCCH is fixed to always use TM mode in the uplink. TM mode does not support segmentation and padding. The MAC header always includes only the TCTF header, which consists of 2 bits. Therefore, the RRC message that is carried in the MAC SDU must be adapted to meet the required size of the MAC SDU.
RRC messages are generated using a special coding known as ASN. 1 coding. FIG. 9 illustrates ASN. 1 coding of an RRC message for CCCH.
The different information elements that form the R99 part and the extension part are encoded by the means of the ASN. 1 to create the basic production. The encoder adds padding bits to ensure that the number of bits is a multiple of 8. In order to adapt the RRC PDU size to the size of the MAC-SDU for the CCCH messages on TM, the RRC layer adds additional padding.
The CCCH logical channel is used to transmit Cell Update messages, RRC connection request messages and URA update messages in the uplink. The messages have different sizes depending upon the information that is added to the message. The messages also contain information on the measured results of neighboring cells, for example quality and timing information such as measured results on RACH.
Conventional methods adapt the size of the messages transmitted on the CCCH logical channel so that the RLC PDU with the MAC header fits inside the transport block that is used in the RACH. A conventional method 1 for transmitting messages on the CCCH logical channel is illustrated in FIG. 10.
As illustrated in FIG. 10, information regarding the existing PRACH configurations is transmitted to a UE 2 (S10). Based on the existing transport PRACH configurations, the UE 2 selects the PRACH according to an algorithm (S12). The UE 2 generates a message including all information elements for transmission over the PRACH (S14). The UE 2 compares the message size with the transport block size of the first transport format of the corresponding RACH and adapts the message size by deleting measurement information until the message fits within the transport block size (S16). The UE 2 then transmits the adapted message via the PRACH (S18).
In a UMTS system several PRACHs may be configured in a cell. A UE 2 in RRC-idle or RRC-connected mode reads a list of PRACH channels from the system information blocks. Each PRACH channel may have a list of available transport formats.
In TDD (Time Division Duplex), the TTI (Transmission Time Interval), or duration of the transmission of a transport block, of a PRACH may be different depending on the transport format. In 1.28 MCPS TDD mode, the UE 2 always selects the largest TTI of the transport formats that are suitable for transmission of the transport block set.
In FDD (Frequency Division Duplex), each PRACH channel has a fixed TTI. Each transport format is characterized, among other characteristics, by a transport block size and the number of transport blocks that may be transmitted during one TTI.
In order to select the PRACH, the UE 2 first must select the TTI to be applied. Once the TTI is selected, the UE 2 selects one PRACH channel randomly from the PRACHs that exist that use the selected TTI length. If PRACHs with different TTI lengths exist, the TTI length is selected according to the method 50 illustrated in FIG. 11. Otherwise, the TTI of the configured PRACHs is utilized.
Referring to FIG. 11, the UE 2 selects a transport format with 10 msec. TTI based on the available transport formats in step S52. From the transport formats supported by all RACHs, those formats that have a TTI of 10 msec. and correspond to a single transport block of all configured RLC sizes are kept.
For example, the RLC size applicable for RB0 is kept in RRC-idle mode and the RLC sizes configured with explicit RB mapping information are kept in RRC-connected mode. If more than a single transport format is applicable, the UE 2 may select any of the available formats.
Preferably, the UE 2 selects the transport format that is intended for use by the next transmission. If such information is not available, the transport format corresponding to the largest configured RLC size is selected.
In step S54, the UE 2 calculates the power margin by estimating the transmit power necessary to transmit a transport block set on the RACH with a given transport format. The algorithm used for this calculation is specified by the 3GPP standard and uses, among other input parameters, the TTI, the transport block size and the number of transport blocks to be transmitted.
In step S56, the calculated power margin is compared to 6 dB. If the power margin is greater than 6 dB, the 10 msec. TTI is selected in step S58. If the calculated power margin is not greater than 6 db, the 20 msec. TTI is selected in step S60.
If the size of a CCCH message is too large using the conventional methods 1, 50, a UE2 might completely delete the information on the measured results of neighboring cells, for example measured results on RACH, even though the quality and timing information might be needed in the RNC 10. Without the quality and timing information, a connection may not be established with the RNC 10 when a UE 2 moves to another cell. The UE 2 may not be able to transmit data and a current call may be interrupted or a new call may not be initiated.
Because the UMTS standard restricts a UE 2 to always use the first transport block size of the selected PRACH, there is only one transport block size available for SRB0. Therefore, the size of the messages is limited to the size of the transport block.
It has been suggested to change the size of the first transport format of the PRACH. However, there is no guarantee that all mobiles terminals will support a size change of the SRB0. Therefore, as long as there are mobile terminals that do not support another transport block size used in the PRACH, messages that are transmitted via the CCCH in the uplink may not be extended in new Releases of the UMTS standard.
Therefore, there is a need for a method and apparatus that conforms to a new UMTS standard that allows messages to be transmitted via the CCCH channel that are larger than the currently available transport block size, while not impacting the operation of mobile terminals that do not conform to the new UMTS standard. The present invention addresses these and other needs.

This patent is subject to a terminal disclaimer.

Method and apparatus for providing enhanced messages on common control channel in wireless communicaton system


Methods and apparatus are disclosed for improved loop unrolling by a compiler. A large class of loops exists for which effective loop unrolling has not previously been performed because they are too large to be completely unrolled, but which do not have a single hot trace that covers an entire loop iteration. The present invention recognizes such loops that have partial hot traces identified using profile data. A set of instructions which constitute a proper superset of the hot trace and a proper subset of the entire loop, and which forms a complete loop iteration is identified. This set of instructions can then be unrolled without unrolling the entire loop.

1. Field of the Invention
The present invention generally relates to computer systems, and more specifically relates to compilers that generate executable code for computer systems.
2. Description of the Related Art
Since the dawn of the computer age, computer systems have evolved into extremely sophisticated devices, and computer systems may be found in many different settings. Dramatic advances in both hardware and software (e.g., computer programs) have drastically improved the performance of computer systems. Modern software has become very complex when compared to early computer programs. Many modern computer programs have tens or hundreds of thousands of instructions. The execution time (and hence, performance) of a computer program is very closely related to the number of instructions that are executed as the computer program runs. Thus, as the size and complexity of computer programs increase, the execution time of the computer program increases as well.
Unlike early computer programs, modern computer programs are typically written in a high-level language that is easy to understand by a human programmer. Special software tools known as compilers take the human-readable form of a computer program, known as "source code", and convert it into "machine code" or "object code" instructions that may be executed by a computer system. Because a compiler generates the stream of machine code instructions that are eventually executed on a computer system, the manner in which the compiler converts the source code to object code affects the execution time of the computer program.
The execution time of a computer program is a function of the arrangement and type of instructions within the computer program. Loops affect the execution time of a computer program. If a computer program contains many loops, or contains any loops that are executed a relatively large number of times, the time spent executing loops will significantly impact the execution time of a computer program.
In order to optimize the performance of modern computer programs, profilers have been developed to measure the run-time performance of a computer program. Profilers typically generate profile data that estimates how often different portions of the computer program are executed. Using profile data, an optimizer (such as an optimizing compiler) may make decisions to optimize loops in a computer program in order to improve the execution speed of the computer program.
Known methods for using profile data to optimize loops in a computer program do not provide an optimal solution in cases where a single hot trace (that is, a single path through which execution follows for most iterations of a loop) does not extend from a beginning of a loop to an end of the loop. As a result, the prior art may yield inefficiencies in loops that result in a slower execution time for the computer program. Application Ser. No. 10/282,811 teaches a method for improving efficiencies in loops by identifying a hot trace and unrolling that hot trace; however additional improvements in loop efficiencies are needed to maximize performance of the computer system.