A synthetic resin guide for a transmission device comprises an elongated rail for longitudinal sliding engagement with a power transmission medium, and a rail supporting member molded as a unit with the rail. The supporting member comprises a plurality of reinforcing ribs which support the rail. The ribs are distributed along the length of the transmission device from a location adjacent one end of the rail to a location adjacent the opposite end of the rail. The guide is formed by injection molding and the reinforcing ribs extend in directions following the flow of synthetic resin during injection molding. Preferably the synthetic resin is a glass fiber reinforced resin. By forming the reinforcing ribs in this manner, high strength and toughness are imparted to the guide, and warpage and torsion, which would otherwise be encountered in a high temperature transmission environment, are reduced.

In general, in a transmission device for a motor vehicle engine or the like, in which mechanical power is transmitted by a medium such as a chain, belt or the like, a movable or fixed guide is attached to a body frame, such as an engine block wall, by a mounting bolt, a pin or the like. The chain, belt, or other power transmission medium, travels in sliding contact with the guide.
In the case of a movable guide, which may be in the form of a tension lever or the like, the guide provides the power transmission medium with appropriate tension to prevent transmission failure resulting from excessive stretching, or excessive loosening, of the power transmission medium. A fixed guide, such as a guide rail or the like, limits the power transmission medium to a predetermined traveling path to prevent vibration noise, side vibration, and disengagement.
FIG. 13 illustrates an example of a conventional synthetic resin guide 100 for a tensioner lever. The guide 100 comprises a slide rail 101, which is in sliding contact with a traveling chain C, and a rail-supporting member 102 provided on the back side of the slide rail 101. The rail supporting member 102 includes a boss 102a having a mounting hole 103 for pivoting attachment to an engine block wall. The rail supporting member also includes a tensioner abutting portion 102b, which cooperates with a tensioner (not shown) for providing appropriate tension to prevent transmission failure resulting from excessive stretching, or excessive loosening, of the chain. The synthetic resin guide 100 includes a plurality of thick reinforcing ribs 102c, each formed at suitable intervals along the rail supporting member 102, to enhance the mechanical properties and toughness of the guide 100.
The conventional synthetic resin guide 100 has several problems preventing it from exhibiting good mechanical properties and toughness. When the guide is injection-molded from an injection gate provided on one end portion of the guide, the reinforcing ribs 102c extend substantially perpendicular to the direction of injection of the synthetic resin P. As a result of the orientation of the reinforcing ribs, the flow of the injected synthetic resin P, which, as shown in FIG. 14, comprises a skin layer-forming resin P1 and a core layer-forming resin P2, exhibits a stagnant fluid state within and around the interior of the reinforcing ribs 102c. The residence, eddy flow, and turbulent flow of the resin P prevent the resin from achieving a strain-free molecular orientation in the interior of the reinforcing ribs 102c. Consequently, the peripheral portions of the ribs are solidified in an strained state. The orientation strain not only causes cracks due to loading during power transmission, but also causes thermal shrinkage resulting from a non-crystalline region in the synthetic resin P. Accordingly, strains such as warpage, torsion and the like occur in a high temperature environment such as in an automobile engine, and the guiding function is not entirely satisfactory.
Referring to FIGS. 15 and 16, when a synthetic resin P, composed of a glass fiber reinforced resin (consisting of a skin layer forming resin P1 and a core layer forming resin P2) is used, ideal mechanical properties and toughness are exhibited when the reinforcing glass fibers F contained in the core layer forming resin are oriented in a direction substantially parallel to the slide rail 101. However, as described above, since the reinforcing rib portions 102c extend substantially perpendicular to the direction of injection of the synthetic resin P, the resin is in a stagnant fluid state in the interiors of the respective reinforcing ribs 102c, and in the peripheral portions thereof. Residence, eddy flow, turbulent flow and the like are generated in the fluid resin, and, as a result, as shown in FIG. 16, the orientation of the glass fibers is disturbed. Thus, in spite of the mixing of glass fibers F in the synthetic resin P to increase the strength of the guide, ideal strength cannot be achieved.
Furthermore, since the reinforcing rib portions 102c impair the flow of the glass fiber-reinforced synthetic resin P, moldability during injection molding is unsatisfactory. Thus, glass fibers F cannot be dispersed in such a way that they are oriented in a specified direction, and cannot be mixed uniformly in the resin. To solve this problem, changing the injection conditions has been tried. However, a higher injection pressure and a longer injection time are required, thereby increasing the cost of injection molding.
Accordingly, objects of the invention are to solve the above-mentioned problems encountered in the prior art, and to provide a synthetic resin guide for a transmission device including reinforcing portions, which exhibits greater strength and toughness, and in which strains such as warpage, torsion and the like in a high temperature environment are significantly reduced.
The synthetic resin guide in accordance with the invention comprises an elongated rail for longitudinal sliding engagement with a power transmission medium, and a rail supporting member molded as a unit with the rail. The supporting member comprises a plurality of reinforcing ribs which support the rail. These ribs are distributed along the length of the transmission device from a location adjacent one end of the rail to a location adjacent the opposite end of the rail. The guide is formed by injection molding, and, in order to achieve the above-mentioned objects, the reinforcing ribs extend in directions such that the flow of synthetic resin during injection molding substantially follows the longitudinal directions of the reinforcing ribs. Preferably, the synthetic resin is a glass fiber reinforced resin. The synthetic resin guide in accordance with the invention, may be either a fixed guide or a movable guide.
In order for the reinforcing ribs to extend in a direction following the flow of resin during injection molding, any arrangement such as an S-shaped arrangement, a curved arrangement, a truss-shaped arrangement, a vein-shaped arrangement, a honeycomb-shaped arrangement, or the like, may be used.
The injection molding process used to produce the synthetic resin guide according to the invention can be an injection molding process in which resin processing is integrally carried out from one end portion in a longitudinal direction of the guide toward the other end portion. For example, any process such as a typical injection molding process using a single synthetic resin, a two-color injection molding process using two kinds of synthetic resins, a sandwich injection molding process in which a core layer resin is injected inside a skin layer, or the like, may be used.
According to the invention the reinforcing rib portions which supports the slide rail extend in directions following the flow of synthetic resin during injection molding of the guide. Thus the reinforcing rib portions behave as auxiliary flow paths, which lead the synthetic resin injected during the injection molding of the guide from one end portion in a longitudinal direction of the guide toward the other end portion, so that injected synthetic resin flows throughout the guide without significant flow resistance, so that the injected synthetic resin flows smoothly to the end of the synthetic resin guide.
Since the synthetic resin is fully molecularly-oriented when solidified, the crystal region of the synthetic resin is increased and thermal shrinkage of the guide is reduced. Furthermore, the pressure required for injection molding of the guide can be reduced to a lower level than in the conventional case, and the injection time can also be reduced.

Method of molding synthetic resin guide for transmission device


The method for removing an inner casing from a machine includes removing a top part of the outer casing, removing a top part of the inner casing, removing the bottom part of the inner casing, before removing the bottom part of the inner casing connecting the bottom part of the inner casing to the rotor, such that the bottom part of the inner casing is supported by the rotor, then rotating the rotor around the longitudinal axis to make the bottom part of the inner casing accessible.

Machines such as axial turbines or compressors have an outer casing that houses an inner casing; the inner casing carries vanes. Within the inner casing a rotor is housed that carries blades.
Blades and vanes must withstand very heavy operating conditions, thus they need periodical checking and controls.
Different methods are known to access the vanes and blades.
For example the upper part of the outer casing and inner casing can be removed and then also the rotor can be removed, in order to access the vanes at the bottom part of the inner casing.
Nevertheless, removing the rotor is very time consuming, thus it is preferably avoided.
It is also known to remove the upper part of, the outer and inner casing, replace the upper part of the inner casing with a ring sector and then provide rollers between the bottom part of the outer and inner casing.
This way the bottom part of the inner casing can be rotated on the rollers, bringing it at the top of the machine, such that it can be removed without removing the rotor.
This method could cause damages between the adjacent parts of the inner and outer casing. For example, this can be caused by the possible relative axial displacement of the inner and outer casing, such that adjacent surfaces of the inner and outer casing that normally are separated by a gap come into contact.

Method for removing an inner casing from a machine


A confocal scanning microscope using a Nipkow disk prevents deterioration of performance in an optical axis direction while maintaining a high measurement speed. The confocal scanning microscope includes a light source, an illuminating device to pass the light from the light source toward a certain direction, and two Nipkow disks each having slit-shaped apertures formed thereon such that the light incident from the illuminating device travels in a form of light which passed through a single aperture. In addition, the confocal scanning microscope includes a first optical system to form an image on a sample by the light passed through the Nipkow disks, and a second optical system to form a second image by the light reflected from the sample and passed through the Nipkow disks.

1. Field of the Invention
The present general inventive concept relates to a confocal scanning microscope to measure critical dimensions of a semiconductor device and an image output device to perform a real time check in a production process of the semiconductor device and image output devices.
2. Description of the Related Art
Confocal microscopes are apparatuses for irradiating a sample with light having a certain wavelength, controlling the light to be reflected from the sample through a confocal aperture, such as a pin hole, and detecting the light only emitted from a focal plane of an objective lens using a photo-detector (PD), the principle of which is disclosed in Korean Patent Laid-Open No. 2002-0084786.
As disclosed in the above mentioned reference, since light reflected from a portion outside the focal plane of the objective lens of the confocal microscope does not pass through the pin hole, and hence, is not detected in the photo-detector, the confocal microscope has not only a high resolution in an optical axis direction but also a resolution higher than that of existing optical microscopes in an direction perpendicular to the optical axis direction. In addition, with the confocal microscope disclosed in the above reference, it is possible to observe a desired plane on the sample and obtain a three-dimensional image of the sample.
Owing to the high resolution and the capability of obtaining the three-dimensional image, confocal microscopes has been widely used in the fields of cell biology and semiconductor chip testing.
As one of methods for obtaining a two-dimensional plane image using such a confocal microscope, Japanese Patent Laid-Open No. Hei 06-018786 discloses a confocal microscope for scanning every point of a measurement area with light using point scanning of a television scan line system. The confocal microscope employs a method of deflecting light in two perpendicular axis directions using two optical deflectors, and scanning each point of the measurement area with the deflected light. However, such a confocal microscope has a problem in that it takes a long time to obtain the two-dimensional image due to a limited mechanical speed of the optical deflectors and a calculation load of serial signal processing.
As a method for obtaining higher image acquisition speed, compared to the method using the optical deflectors, U.S. Pat. No. 5,067,805 discloses a confocal scanning microscope using a Nipkow disk, the principle of which will be described with reference to FIG. 1.
Referring to FIG. 1, the confocal scanning microscope using the Nipkow disk includes a light source 1, a collimating lens 2 for transforming light emitted from the light source 1 into a parallel beam, a beam splitter 3 for changing a direction of the parallel beam incident from the collimating lens 2, a Nipkow disk 4 having a plurality of apertures formed therein such that only a portion of a beam incident from the beam splitter 3 passes therethrough, a motor 5 for rotating the Nipkow disk, a tube lens 6 for transforming a beam, which has passed through the Nipkow disk 4, into a parallel beam, an objective lens 7 for irradiating a sample 8 with the parallel beam incident from the tube lens 6, a first lens 9 for transforming the beam reflected from the sample 8 and passed through the Nipkow disk 4 into a parallel beam, and a second lens 10 for concentrating the beam passed through the first lens 9 onto a two-dimensional photo-detector 11 for acquisition of an image.
The light emitted from the source of light 1 becomes the parallel beam after passing through the collimating lens 2. This parallel beam illuminates a top surface of the Nipkow disk 4 after being reflected at the beam splitter 3. As shown in FIG. 2A, a plurality of apertures 4a each having a pin hole shape are distributed (formed) in the Nipkow disk 4. With this distribution of the apertures 4a, only a portion of the parallel beam irradiating the Nipkow disk 4 passes through the apertures 4a. A beam passed through the apertures 4a propagates at various angles by diffraction, thereby causing an effect as if a point of the light source is placed on each aperture 4a. The tube lens 6 and the objective lens 7 form an image on the sample 8 by irradiating the sample 8 with the beam passed through the apertures 4a. Only a plurality of point regions of an overall observation region on the sample 8, which correspond to the apertures 4a, are illuminated. In order to illuminate the overall observation region on the sample 8, positions of the apertures 4a must be varied. To this end, the motor 5 connected to a center of the Nipkow disk 4 rotates the Nipkow disk 4. When the positions of the apertures 4a are varied with respect to the sample 8 according to rotation of the Nipkow disk 4, the overall observation region on the sample 8 is illuminated.
The beam illuminating on the sample 8 is reflected from the sample 8 and passes through the objective lens 7 and the tube lens 6 for formation of an image on the Nipkow disk 4. At this time, some beam, reflected from a focal plane (f) of the objective lens 7, of the beam reflected from the sample 8, passes through the apertures 4a of the Nipkow disk 4, however, some portion of the beam, reflected from points deviated from the focal plane (f) in the optical axis direction, of the beam reflected from the sample 8, does not pass through the apertures 4a. This accounts for the so-called confocal principle through which high resolution in the optical axis direction can be obtained.
The beam passed through the apertures 4a is incident into the two-dimensional photo-detector 11 through the first lens 9 and the second lens 10 so that an image is formed on the photo-detector 11. As the positions of the apertures 4a are varied according to the rotation of the Nipkow disk 4 by the motor 5, a position on the photo-detector 11 at which the image is formed is varied. Accordingly, an optical signal is transported on the overall region of the two-dimensional photo-detector 11, so that a two-dimensional image can be at once obtained with respect to the sample 8.
FIG. 2B illustrates a shape of the Nipkow disk 4, where slit-shaped curve apertures 4b are formed. In the case of the confocal scanning microscope using the Nipkow disk 4 having the slit-shaped curve apertures 4b formed thereon, an illumination beam passing through the Nipkow disk 4 takes a line shape, and a region to be illuminated on the sample 8 also takes a line shape. When the Nipkow disk 4 is rotated, the illumination beam of the line shape for forming an image on the sample 8 is moved, and accordingly, the image of the line shape formed on the photo-detector 11 is also moved to obtain a two-dimensional image of the sample 8.
However, although the confocal scanning microscope using the Nipkow disk 4 has an advantage of an image acquisition speed higher than that of the confocal scanning microscope using the optical deflector, it has a problem of deterioration of the resolution in the optical axis direction since it illuminates not a point but a plurality of point regions or a line region on the sample for parallel processing of signals.
As shown in FIG. 3, the beam reflected from the focal plane (f) of the objective lens 7 is exactly concentrated on and exits through the apertures 4a of the Nipkow disk 4 through which the illumination beam has been emitted, after passing through the objective lens 7 and the tube lens 6. However, the beam reflected from the points deviated from the focal plane (f) and moved deeper in the optical axis direction is not exactly concentrated on the apertures 4a, forms an image before the apertures 4a, and then, passes through adjacent apertures 4a as well as the apertures 4a through which the illumination beam is emitted. The beam illuminated on the adjacent apertures 41 acts as a kind of noise, which deteriorates optical performance in the optical axis direction.
FIG. 4 is a graph showing a resolution in an optical axis direction when a size of the aperture in confocal scanning microscopes using a single aperture and multiple apertures is changed. In order to obtain the amount of beam of a range within which an image can be measured, it is required to increase the size of the aperture over a prescribed size. However, it can be seen from FIG. 4 that a resolution value in the confocal scanning microscope using the multiple apertures is abruptly increased as the size of the aperture is increased, which results in deterioration of performance of the confocal scanning microscope.

Confocal scanning microscope using two Nipkow disks


A communication system for a plurality of carriages that travel along a rail. A power cable extends along the rail. The cable is used to convey electric current that drives the movable bodies and is also used to carry information between the carriages. The carriages communicate with one another by superimposing communication signals on the current flowing through the cable to transmit information and by extracting communication signals from the current flowing through the cable to receive information. A control unit at a fixed station relays communication signals transmitted between different carriages. The control unit receives communication signals, which the carriages transmit, from the cable, amplifies the signals, and returns the signals to the cable. The recipient carriage receives an amplified communication signal from the cable.

The present invention relates to a method and system for communication between a plurality of carriages that travel along rails. More particularly, the present invention pertains to a method and system for performing communication by superimposing signals on electric current that flows through a power cable extended along rails.
In the prior art, a monorail type carriage (movable body) that travels along a rail, which is hung from a ceiling of a factory or a storehouse, to transfer articles between stations is known. Japanese Unexamined Patent Publication No. 6-153305 describes a system for supplying electric power to such a carriage. In the system, a pickup coil provided on the carriage is opposed to a power cable, which extends along a rail, in a non-contacting state. The pickup coil generates induced electromotive force from the alternating current that flows through the cable. The induced electromotive force is supplied to the carriage and used as the electric power that drives the carriage.
More specifically, as shown in FIG. 9, an alternating current of a certain voltage (e.g., 200V) flows through two cables 53 that are supported along a rail 51 by a supporter 52. A carriage obtains electric power through a pickup coil 54 opposed to the two cables 53. The pickup coil 54 includes an E-shaped core 55, a projection 55a projecting from the core 55, and a coil 56 wound about the projection 55a.
The carriage (local station) communicates with a fixed station (key station) located on the ground. The operation of the carriage is controlled by command signals sent from the fixed station. Communication between the fixed station and the carriage may be obstructed by crosstalk when employing a wireless system. Thus, a trolley wire extended along the rails is normally used for communication between the fixed station and the carriage. However, abrasion tends to occur on the trolley wire where it contacts a collecting brush. Furthermore, the wiring of the trolley wire is burdensome.
To solve such problems, the assignee of this application has employed the power cables for communication. As shown in FIG. 10, alternating current supplied by a high frequency power source 62 flows through the cables 53, which are arranged along the rail 51. A carriage 61 travels on the rail 51. Communication signals are superimposed on the alternating current flowing through the cables 53 by transmission antenna coils 64 provided on the fixed station 63. A communication antenna coil 65 (refer to FIG. 11(b)) is wound about a core 66 on each carriage 61. This structure enables communication between the carriage 61 and the fixed station 63.
As shown in FIG. 10, when a plurality of carriages 61 travel along the rail 51, collisions between the carriages 61 must be avoided. Collisions may be avoided by installing a sensor on each carriage 61 to detect objects located in front of the carriage 61 with respect to its moving direction. However, at curved portions of the rail 51, an object in front of the carriage 61 may not be detected until the carriage 61 is in close proximity to the object. In such cases, it may be too late to prevent collision when the object is detected. Therefore, communication is carried out between carriages 61 to confirm the location of other carriages 61 and avoid collisions.
As shown in FIG. 11(a), the antenna coils 64 are directly wound about the cables 53 at the fixed station 63. This decreases leakage flux and minimizes signal attenuation. However, the antenna coil 65 of the carriage 61 cannot be directly wound about the cables 53 since the carriage 61 must travel along the cables 53. Therefore, as shown in FIG. 11(b), the antenna coil 65 is wound about the core 66, which is arranged in the vicinity of the cables 53.
The arrangement of the antenna coil 65 in the vicinity of the cables 53 increases flux leakage and signal attenuation in comparison to directly winding the coil 65 about the cables 53. Hence, in a case such as that shown in FIG. 12, a signal (frequency fO) superimposed on the alternating current, which flows through the cables 53, and transmitted from carriage M to carriage N is weakened by the signal attenuation that takes place when the signal is transferred from the antenna coil 65 of the carriage 61 denoted as M to the cables 53. The signal is further weakened when transferred from the cables 53 to the antenna coil 65 of the carriage 61 denoted as N. This results in poor reliability of communication between carriages 61. Additional attenuation of the signals takes place, especially when using a long rail 51, when the signal transmission distance between carriages 61 is great. This may cause erroneous signals to be received by the recipient carriage 61 and stop the entire system or cause other problems.

Communication method and apparatus for conveyor carriages

Kabushiki Kaisha Toyoda Jidoshokki Seisakusho


A combined file allocation table file system (CFAT file system) uses two or more FAT file systems with different cluster sizes to form a single user visible FAT file system to reduce disk fragmentation. The FAT file system having the largest cluster size is used to store all of the other small FAT file systems as files with holes. The clusters of the small FAT file systems thus do not occupy disk space until they are allocated. Files containing user data are stored in one or many of the large and small FAT file systems to achieve optimal storage. More clusters are available for storing files with sizes that are smaller than the size of one large cluster. A CFAT file system includes: a large file allocation table for large clusters, a file allocation table extension to provide holes within the CFAT file system, and any number of small file allocation tables providing a variety of small cluster sizes. A file is stored in clusters as large as possible except for the last cluster which is stored in only as large a cluster size as is needed. Other allocation strategies are possible. The Small FAT file systems are contained within regular files of the Large FAT file system.

File system services provided by the operating system of a computing system are responsible for managing the allocation of space of storage media. These file system services also provide a logical framework to the users of the computer for accessing data stored in the storage media. The logical framework usually includes a hierarchy of directory structures to locate a collection of files that contain user-named programs or data. The use of directories and files relieves the users from having to find the actual physical location of the stored information in a storage medium. Many different types of file systems are known. By way of example, popular file systems include various UNIX.TM. based file systems and the WINDOWS NT.TM. file system. One UNIX.TM. file system that incorporates the concept of "holes" (discussed below) is described in "The Design and Implementation of the 4.3BSD UNIX.TM. Operating System", S. Leffler, M. McKusick, M. Karels and J. Quarterman, chapter 7, Addison-Wesley, 1989. The WINDOWS NT.TM. file system is described in "Inside the Windows NT.TM. File System", H. Custer, Microsoft Press, 1994.
A typical file system implementation, hereafter referred to as a file system, converts from the user abstraction of a file as an array of bytes to the structure imposed by the underlying physical medium of the storage medium. Typically, magnetic disks are organized into fixed size sectors. Although the user may wish to write a single byte to a file, the disk may read or write only in multiples of sectors. Thus, in order to modify a single byte in a file, the file system must first read in the sector containing the byte to be modified, then replace the affected byte, and finally write the sector back to the disk. This operation of converting a user's random access to an array of bytes into reads and writes of disk sectors is known as block input/output or "Block I/O."
To effectively support Block I/O, a file system typically divides the array of bytes in a file into a set of fixed size clusters. A cluster may be defined as the minimum size that may be allocated for a disk. For example, if a file system's cluster size is 8192 bytes, then the first cluster allocated to a file would contain bytes 0 to 8191 of the file, and the next cluster of the file would contain bytes 8192 to 16383, etc. These clusters of a file are then stored to a disk in units of a cluster as well. The file system also divides the sectors of a disk into a set of fixed size clusters. The size of each cluster is called the cluster size. Each cluster of a disk is assigned a unique address, called a cluster number. Cluster numbers are assigned consecutively, starting from 0. If a disk has N clusters, then cluster number N-1 is the last cluster of the disk. If each cluster of a disk contains 8 sectors, then cluster number 0 corresponds to sectors numbered 0 to 7 on the disk, and cluster number 1 corresponds to sectors numbered 8 to 15 of the disk, etc. Thus, the conceptual notion of a cluster within a file is eventually written to disk at a particular cluster that has a unique cluster number.
Physical storage 10 containing clusters divided up into sectors is shown in FIG. 1. Shown is the linear physical address space of a disk (for example). The disk contains sectors of data that are organized into clusters. These clusters are shown symbolically as being linear, however, a disk controller would be responsible for allocating an individual cluster to a particular region of the disk. Shown in particular is a disk having at 12 a cluster 0 up through at 14 a cluster N-1. The disk contains N clusters. Each cluster may contain eight sectors, for example. For example, cluster 0 would correspond to sectors 0-7, cluster 1 would correspond to sectors 8-15, etc. A total of X sectors may be present on the disk. It should be appreciated that this disk as mass storage in a computer may take a variety of forms. The disk may be any type of hard disk that uses magnetic media, a floppy disk, or the like. Also the disk may be any other type of physical storage in a computer such as an optical disk, RAM, or the like.
Because a file system or disk controller in a computing system may write data to these clusters continuously or randomly, it is important to keep track of which clusters on the disk contain data, i.e. which clusters are allocated. It is also important to keep track of which clusters contain data for a given file. One method to keep track of such information is through the use of a File Allocation Table (FAT).
A particular file system implementation uses a file allocation table (FAT) to manage the allocation of clusters of a disk. These file system implementations that use a file allocation table are hereafter referred to as FAT file systems. The MSDOS, OS/2, Window 3.1 FAT and the Window 95 VFAT file systems are examples of FAT file systems that are available commercially. A FAT file system will now be described generally, and then an example is provided below with reference to FIG. 2.
Typically, a FAT file system uses one file allocation table (FAT) for each disk under its control. Each entry in a FAT for a disk is associated with (or maps to) a cluster of the disk. The first FAT entry is associated with the first cluster of the disk. The next FAT entry is associated with the next cluster of the disk, and so on. If a disk has N Clusters, then the FAT for the disk has N entries, and the last FAT entry is associated with the last cluster of the disk. In other words, it can be said that the cluster number for each cluster on the disk is used as an index into the FAT to access the FAT entry for that particular cluster on the disk.
The contents of each FAT entry for a particular cluster on the disk is itself a cluster number (representing another physical cluster on the disk) and this FAT entry is used to indicate: (1) whether the particular cluster (associated with the FAT entry) has been allocated or not (the special cluster number 0 is typically used to represent an unallocated cluster); (2) whether this cluster is the last (or only) cluster in a file (the last cluster of a file is usually represented by an invalid cluster number such as "-1" in the FAT entry for that particular cluster); and (3) the next cluster of the file. In other words, for a particular cluster of a file that is stored on disk, its cluster number (where it is stored on disk) serves as an index to the FAT, and the value stored at this FAT entry is another cluster number representing where the next cluster of the file is stored on the disk.
A file in a FAT file system having Z clusters uses Z entries in the FAT. One of the directories in a FAT file system contains a directory entry for a given file that identifies the cluster number of the first cluster of that file. And the FAT entry that corresponds to the cluster number of the first cluster of a file identifies the cluster number of the second cluster of the file, and so on. In this fashion, the FAT entries corresponding to the cluster numbers on disk for the clusters of a file form a linked list. The FAT entry for the last cluster of a file contains an invalid cluster number such as "-1", to indicate that this cluster is the last cluster of the file. The minimum space allocation unit in a FAT file system is one cluster. Since the clusters of a file may not necessarily be allocated consecutively, each read or write operation usually requires one I/O operation.
FIG. 2 shows one implementation of a file system 50 in which a file directory 51 is able to access a file allocation table 70 in order to keep track of the status of the clusters on the disk. The file directory 51 may represent a complex hierarchy of directories within a file system as will be appreciated by those of skill in the art. The file directory 51 contains a File Name field 52 and an Initial Cluster Number field 54. The File Name field lists files within the file system and the Initial Cluster Number field indicates by cluster number the first cluster on disk that is used by that file to store its data.
The structure of the file allocation table 70 will now be described. A file allocation table (FAT) may be implemented using a wide variety of data structures. It is preferable to implement a file allocation table 70 using an array in which the index of the array represents a cluster on the disk and the data at the location in the array according to the index represents the status of that cluster. In other words, the cluster number serves as an index into the FAT to access a corresponding element of the array that indicates the status of the cluster on the disk identified by its cluster number. For example, the FAT 70 is shown as having an index Cluster Number 72 that ranges from 0 to N-1. The elements of the array are a status region 74 that will indicate not only the status of a particular cluster on the disk, but also the location of the next cluster within a file. A wide variety of status information for a particular cluster may be contained within the status region 74. By way of example, it is possible to keep track of whether a cluster has been allocated or not, whether it is the last cluster within a file, etc.
For example, the FAT 70 operates to indicate the status of all of the clusters of the disk 10 shown in FIG. 1. For example, in determining the status of cluster 1, one may refer to the FAT 70. To determine the status of cluster 1, an index of 1 is used as a cluster number to gain access to the status region 76 for that cluster. As shown at 76, the status of cluster 1 is represented by a 0, indicating that this cluster is currently unallocated. A positive number of 1 or greater may indicate that the cluster is currently allocated to a particular file. Also a status of "-1" for a particular cluster may indicate that this cluster is the last cluster containing data for a particular file. It should be appreciated that other numerical conventions may be used to represent the status of a cluster.
The use of the FAT 70 with the file directory 51 will now be described. Within the file directory 51 is a File1 56 that has an Initial Cluster Number of 3. This indicates that the first cluster of data for File1 is stored in cluster 3 on the disk. This Initial Cluster Number of 3 also serves as a pointer 58 to the FAT 70. This pointer 58 points to the status region as identified by the index 3 that represents the status of cluster number 3. The status region for the index 3 is the number 2 that indicates not only that this cluster 3 has been allocated but also that the next cluster containing data for this file is cluster 2. This number 2 also serves as a pointer 78 to the status region of the FAT as indexed by cluster number 2. Contained within this status region for the cluster number 2 is the quantity N-1 that indicates not only that cluster 2 has been allocated but also that the next cluster that contains data for this file is located at cluster N-1. This quantity N-1 also serves as a pointer 80 to the status region of the FAT as indexed by the quantity N-1. Contained within this region is the quantity "-1" that indicates not only that cluster N-1 has been allocated to this file, but also that this cluster N-1 is the last cluster containing data for this file.
The File2 is represented in a similar manner. Within the file directory 51 is a File2 60 that has an Initial Cluster Number of 5. This indicates that a first cluster of data for File2 is stored in cluster 5 on the disk. This Initial Cluster Number of 5 also serves as a pointer 62 to the FAT 70. This pointer 62 points to the status region as identified by the index 5 that represents the status of cluster number 5. The status region for the index 5 is the number "-1" that indicates not only that this cluster 5 has been allocated but also that this cluster 5 is the last cluster containing data for this File2. Of course, other files within the file system may be represented in the file directory and the FAT. Files that are empty may be indicated by storing a "0" in the file directory at the Initial Cluster Number.
While most applications write data to a file sequentially, some applications write data randomly to any offset in the file. For example, an application may create a new file and then write several bytes starting at an offset T within the file. In this case, bytes between offset 0 and offset T-1 of the file will have never been written, but they are logically part of the file and are generally treated as if they all have the value zero. Also, the use of a hashing function in a database may result in clusters of a file containing nothing but zeros. In a FAT file system, clusters of a file that are completely zero are still treated as containing data; a cluster will be allocated on disk and a cluster full of zeros will be written to disk.
Since it is wasteful to store a physical cluster for a corresponding logical cluster of a file that has never been written (i.e. full of zeros), one technique employed by some file systems such as most UNIX.TM. based file systems is to avoid the actual allocation in mass storage for such a zero cluster. The file system designates a special physical cluster address, usually "0", that represents the address of a special, but non-existent, physical cluster that is full of zeros. This special physical cluster is commonly called a "hole." Prior art FAT file system implementations have typically had no such capabilities for representing holes. However, U.S. patent application entitled "File Allocation Tables with Holes" by inventors Thomas K. Wong and Peter Madany, Ser. No. 08/669,632 (allowed), filed Jun. 24, 1996, does describe a technique for representing holes within a file system that uses a file allocation table. The use of holes with a FAT file system avoids allocation of physical storage when it is not needed.
Wong, et. al, extends a FAT file system to support the use of files with "holes". It also uses this concept of "holes" within a FAT file system to support file system level compression. In this way, both compressed and expanded files in a FAT file system may coexist. Also, new disks may be configured with additional FAT entries to support compression.
Typically, a disk with N clusters in a FAT file system will have a file allocation table (FAT) that contains N entries, representing the clusters of the disk numbered 0 to N-1. Wong, et. al, provides a file allocation table extension (FAT extension) that allows for additional entries numbered from N to M-1. Thus, a total of M entries are available in the FAT and FAT extension. For example, if a disk has 10 clusters, and a FAT extension has entries, the entries in the FAT will be numbered from 0 to 9, and the FAT extension entries will be numbered from 10 to 14 for a total of M=15 entries. This FAT extension represents those clusters that are all zeros within the file system and as such provides for a way to keep track of such clusters without having to write them to disk. Thus, for a cluster that is all zeros, this cluster is not written to disk but is assigned a cluster number of N or greater. Thus, any cluster of a file with a cluster number greater than or equal to N is non-existent and is treated as if it were a cluster that is full of zeros. This representation of a zero cluster in the FAT extension is called a "hole".
It should be appreciated that clusters other than those full of zeros may be treated as "holes." For example, the convention used may be that clusters that contain all "1's" are considered as being blank and that such clusters should not be stored to disk but should be represented as a "hole". Also, a cluster that contains a uniform pattern of bits may be considered as not appropriate for writing to disk and may be represented as a "hole." Any type of data pattern represented in a cluster that need not be written to disk may be represented as a "hole."
Referring now to FIGS. 3 and 4, an embodiment of the technique described in Wong, et. al is illustrated in which an extension of a FAT is used to represent the concept of "holes" within a particular file. FIG. 3 shows at 200 a particular File3 and symbolically where its data may be stored on the disk. For example, File3 202 contains three logical clusters of data 204, 206 and 208. Relative to File3 only, these three clusters of data may be referred to as file logical clusters 0, 1 and 2. The clusters 204 and 206 each contain all zeros whereas the cluster 208 contains actual data. In previous implementations of a prior art FAT as shown in FIG. 2, cluster 204 is stored at cluster 3 on the disk, cluster 206 is stored at cluster 2 on the disk, and cluster 208 is stored at cluster N-1 on the disk. This storage of the data of File3 on the disk is shown symbolically at 210. As can be appreciated, if clusters 204 and 206 contain nothing but zeros, it is wasteful to store complete clusters full of zeros on the disk. Accordingly, an extension of a FAT may be used to represent these zero clusters and to avoid the allocation of physical clusters on disk for zero clusters. This representation 212 will be explained below with reference to FIG. 4.
FIG. 4 shows at 250 a traditional FAT 70 enhanced by a FAT extension 80 that is used in conjunction with a file directory 51. The use of this FAT extension 80 will be discussed with reference to the representation of the storage of File3 of FIG. 3. As discussed above, a FAT 70 is represented as an array in which the index of the array is a cluster number 72 that corresponds to a physical cluster on the disk, and the data stored at the element corresponding to the index represents the status of that particular cluster whose number is indicated by the index.
A FAT extension 80 may also be represented by an array that also has as an index a cluster number 84 and a status region 82. It may be possible to implement this FAT extension 80 using a wide variety of equivalent data structures. As the FAT extension 80 is an extension of the FAT 70 its index begins with cluster number N up to a cluster number M-1. As the disk of the computing system still only contains N physical clusters, the index cluster number 84 of the FAT extension 80 that ranges from N to M-1 does not correspond to physical clusters on the disk. As such, an index into the FAT extension 80 may be used to represent that a cluster of a file contains all zeros instead of allocating an actual physical cluster.
In this example, File3 has logical clusters 0 and 1 of all zeros and a logical cluster 2 that does contain data. In the prior art, these first two clusters of File3 that contain zeros are allocated to actual physical clusters on the disk. However, by using the FAT extension 80, these first two clusters of File3 that contain zeros may be represented by using entries within the FAT extension 80 instead of allocating an actual physical cluster on the disk. Shown is a file directory 51 that has within it a File3 56 that has an Initial Cluster Number of N+2. This reference N+2 serves as a pointer 58 to an entry within the FAT extension 80 indexed by the cluster number N+2. Because this initial cluster for the File3 is located at the cluster number N+2 this indicates that this initial cluster is full of zeros. At the cluster number N+2 is the quantity N+5. The quantity N+5 at this location indicates the next cluster for File3 is also represented within the FAT extension 80 at the cluster number N+5. The quantity N+5 serves as a pointer 86 to the entry located at cluster number N+5. Because this second cluster is represented at the cluster number N+5, this means that this second cluster is also completely full of zeros. Within the FAT extension 80 at the cluster number N+5 is the quantity N-1. The quantity N-1 also serves as a pointer 88 back to the FAT 70 to the entry index by the cluster number N-1. Because this third cluster of File3 is indexed by the cluster number N-1 this means that the third cluster does actually contain data and is stored at cluster N-1 on the disk. And because the FAT 70 at cluster number N-1 contains the status of "-1", this means that this third cluster is the last cluster containing data for this file.
Thus, it can be seen that physical clusters for File3 with a cluster number greater than or equal to N contain only zeros and are not represented on disk, whereas physical clusters with a cluster number of N-1 or less contain data and have allocated disk space. This representation is shown symbolically at 212 in FIG. 3. It should also be appreciated that the clusters on the physical disk that contain data for a particular file as well as the zero clusters may be found by searching from the file directory through a form of a linked list until the quantity "-1" is reached. In this fashion, a conceptual array for the File3 may be created that keeps track of where each logical cluster of File3 is represented.
However, other challenges exist for users of a FAT file system aside from the representation of holes. One major problem facing users of a FAT file system is to assign the cluster size for the FAT file system when the FAT file system is first formatted. Once set, the cluster size of a FAT file system cannot be changed easily. To change the cluster size, all the data from the disk must be first copied to a temporary storage location. Next, the disk must be reformatted with the new cluster size, and finally all of the data from the disk in temporary storage must be recopied back onto the disk. This is a time consuming and possibly error-prone procedure that most users are not willing to perform. Thus, it is important for an optimal cluster size to be chosen initially.
If the cluster size of a FAT file system is set too small, then more clusters will be needed to store the data of a file. If the file is not contiguous on disk (which is common), then each cluster must be read or written individually. Thus, small cluster size degrades the file system read/write performance since more disk I/Os are needed to read or write the data of a file. On the other hand, a cluster size for a FAT file system that is set too large may also cause problems. Since the number of clusters available on a disk depends on the cluster size, a larger cluster size will result in a smaller number of clusters available on a disk. Because each non-empty file needs at least one cluster, a larger cluster size results in a smaller number of files that can be stored on a disk. Also, if the cluster size is set too large, there may not be enough file data to fill up all the sectors in a cluster for that file. Sectors that constitute a cluster of a file that are not needed to store the data of the file cannot be used to store data from other files, resulting in many unused sectors on a disk. This is commonly known as a disk fragmentation problem.
Thus, it is desirable to create a FAT file system with a large cluster size in order to maximize I/O performance. It is also desirable to create a FAT file system with a relatively small cluster size in order to increase the number of available clusters in a FAT file system so that more files can be stored in a FAT file system. At the same time, it would be desirable to reduce the disk fragmentation in a FAT file system in order to have efficient usage of storage space.

Disk fragmentation reduction using file allocation tables


The invention pertains generally to miscible polymer blends which can be used in optical applications, particularly in liquid crystal displays and optical adhesives, in that they are essentially birefiringence-free. The polymeric blend alloy includes a first polymer having an inherent positive birefringence and a second polymer having an inherent negative birefringence, the first and second polymers being soluble within each other to predefined limits. The polymer blend is an essentially birefringence-free film layer suitable for use in liquid crystal displays which has adequate mechanical properties, such as dimensional stability, permeability to water vapor, scratch-resistance and insensitivity to temperature, in that it is possible for them to be processed continuously and flexibly to all the required shapes. The polymer blends can be prepared not only from solvent solutions, but by melt-mixing as well.

Liquid crystals are useful for electronic displays because light travelling through a thin film of liquid crystal is affected by the birefringence of the film, which can be controlled by the application of a voltage across the film. Liquid crystal displays are desirable because the transmission or reflection of light from an external source, including ambient light, can be controlled with much less power than is required for luminescent materials used in other displays. Liquid crystal displays are now commonly used in such applications as digital watches, calculators, portable computers, and many other types of electronic equipment where the need exists for long-lived operation, with very low voltage and low power consumption. In particular, portable computer displays benefit from liquid crystal displays where display power utilization must be minimized to permit the battery to operate for as long a period of time as possible before recharging, while allowing the majority of the battery utilization to be directed toward computational efforts.
Glass has typically been used in visual displays which utilize liquid crystal materials. However, the use of glass has a number of disadvantages. For reasons of cost, alkali metal silicate glasses are used, and these must be coated with SiO in order to prevent the migration of the alkali metal. Additionally, the ultimate shapes are somewhat limited, in that only certain shapes can be economically processed. Chipping of glass plates is also an inherent problem.
There have been attempts to use transparent plastics as a substitute for glass. Transparent polymers can be inexpensively molded, as opposed to requiring more expensive grinding processes, but they are typically anisotropic, causing light to be refracted through them along several paths. This birefringence leads to the distortion of light waves passing through optical products made from such plastics, and detrimentally affecting their performance. U.S. Pat. No. 4,228,574 describes a liquid crystal display using plastic. However, as a rule, plastics are neither particularly isotropically, nor particularly mechanically or chemically stable, nor inexpensive. However, as shown in the '574 patent, they are well suited for automated production. It is evident, that the technology of glass displays cannot be simply transferred to plastics. Although a plastic can be found which closely matches, or is even superior to, the properties of the glass for each process step of the glass technology, no cell made of plastic has yet been described which would be equally as good as the glass cell, simply because all of the properties must be found by one plastic.
It has been proposed to use polyesters in place of glass. As a film, polyester is highly birefringent, and thus cannot be employed in the customary components using polarizers. Cellulose butyrate is isotropic, but is unsatisfactory in respect of its mechanical, especially thermal, and chemical properties, and has undesirable light scattering properties. Polycarbonate has also been proposed, but it is highly birefringent.
This invention generally pertains to optically isotropic devices or components, and more particularly to optically isotropic devices or components made of an optically isotropic polymeric material which is a blend of at least two completely miscible polymers. By the term, "optically isotropic", it is intended to refer to the properties in certain materials wherein their optical properties are the same in all directions, such properties including the index of refraction and light absorption.
Very few materials are optically isotropic. Few, if any molded organic polymeric materials are optically isotropic. Such transparent or partially transparent polymers as polyethylene, Lucite.RTM., trade mark of the E.I. duPont de Nemours Company, polymethylmethacrylate (PMMA), etc., are not optically isotropic. This may be seen by making a relatively thin layered sample of the polymeric material and then determining its birefringence and absorption of polarized light. Birefiingence of the sample is determined by finding the indices of refraction of the sample for polarized light in one direction and that for polarized light in a direction perpendicular to the first direction. The difference in the two indices of refraction is the birefringence of the sample material.
Even when a polymeric material has zero birefringence in its bulk state, the processing of such a material into a device, such as by extrusion or injection molding places stresses on the material in the direction of flow. Such mechanical stresses induce orientation of the polymer molecules, which almost always results in flow-induced birefringence.
Thus it can be seen that what is still lacking in the prior art is a material which can cycle between low and high temperature without associated delamination, the refractive index of which can be adjusted to fit the needs of the application, and the birefringence of which can be tailored.

Non-birefringent optical adhesives and films


A device for aligning with a king pin on a trailer comprising: a first bar having a first coupler at one end thereof; a bar having a second coupler at one end thereof; first and second couplers adapted for attachment to said king pin; each bar having a projection therefrom for aligning said rods on said trailer when said couplers are attached to said king pin.

The transportation of goods by truck, rig and trailers is a key industry in modern society. However, it is not unusual for the axle or axles on a trailer to get out of alignment. This may occur on account of the trailer wheels striking an abutment or from the trailer body becoming bent or from some other reason. Such out of alignment conditions of the axle or axles of a trailer will lead to rapid tire wear which results in a big expense for the trailer owner or at the same time, creating a hazardous condition which may cause jackknifing and makes it difficult to control the trailer easily on the road.
Furthermore, there is a lateral drag on the back end of the trailer which in turn causes tire wear on the trailer tractors and difficulties in handling the tractor. Accordingly it is not unusual for tractors to run at excessive torquing. All of these conditions create unnecessary fuel consumption, deterioration in the life of the tractor, tires wearing prematurely, strain on engine parts and increased engine down time.
Accordingly, there is a need for devices to measure the distance between a plurality of axles on a trailer. There is also a need for an improved method for aligning the axles on a vehicle.
There have been a number of arrangements heretofore which have been designed for aligning axles for trailers. For example some operators use a tape measure to measure the distance between the centre line of the king pin and the ends of each axle. This tends to be inaccurate as the tape tends to sag. Furthermore obstacles under the trailer are encountered by the sagging tape making it difficult to obtain an accurate reading.
Other arrangements are shown in U.S. Pat. No. 2,479,723 which relates to a method and means for aligning the rear axles of trailers. Furthermore, U.S. Pat. No. 2,590,722 relates to a device for aligning the wheels and axles of a vehicle in relation to the line of draft of the vehicle.
Moreover, U.S. Pat. No. 2,632,256 relates to an axle alignment device while U.S. Pat. No. 2,845,718 relates to gauging and aligning devices for vehicle axles.
Another arrangement for aligning of axles of trailers is shown in U.S. Pat. Nos. 2,877,560, 3,088,214 and 3,137,076.
U.S. Pat. No. 3,162,950 also relates to a method and means for a trailer axle alignment while U.S. Pat. No. 3,279,084 relates to a trailer axle misalignment and wheel runout indicator and method.
Other arrangements for axle aligning are discussed in U.S. Pat. Nos. 3,325,905, 3,566,476, 3,686,770, 3,962,796, and 4,055,899.
U.S. Pat. No. 4,347,668 relates to apparatus for aligning the axles of trailers having an instrument case connected by an elongated spring-loaded cable to the trailer king pin and connected by a pair of cables to clips releaseably fastened on space location to the trailer axle.
Furthermore, U.S. Pat. No. 4,413,420 relates to a vehicle geometry checking apparatus or U.S. Pat. No. 4,569,140 relates to a thrust line wheel alignment apparatus and method.
Moreover U.S. Pat. No. 4,800,651 relates to an apparatus and method for aligning axles with respect to the frame of the vehicle and for determining wheel camber thereof.
Furthermore, U.S. Pat. No. 4,942,667 illustrates a portable apparatus for aligning the axles of a tractor, a trailer, or other vehicle for detecting bins, bows, twists and other irregularities in vehicle frames which a light source has used to provide a reference plane from which measurements can be taken. Such arrangement illustrates a complicated and expensive means for aligning axles on a trailer.
Further, U.S. Pat. No. 5,125,164 relates to a portable axle and frame alignment tool while U.S. Pat. No. 5,157,838 shows a vehicle axle alignment instrument and method.
A tandem axle alignment device is illustrated in U.S. Pat. No. 5,367,778 while U.S. Pat. No. 6,021,576 relates to a trailer trammel. Finally, U.S. Pat. No. 6,233,837 relates to an axle alignment system which includes a transmitter, reflector and an indicator area.
These and other devices and methods described are relatively complicated and expensive means for aligning the axles on a trailer.
It is an object of this invention to provide an improved device and method for aligning at least one axle of a wheel relative to the king pin of a trailer.
It is an aspect of this invention to provide a device for aligning with a king pin on a trailer which comprises a first bar having a first coupler at one end thereof, a second bar having a second coupler at one end thereof, whereby the first and second couplers are adapted for attachment to the king pin, each bar having a projection therefrom for aligning said rods on said trailer when said couplers are attached to such king pin.
It is another aspect of this invention to provide a tool for measuring the distance between an axle on each side of a vehicle comprising two telescoping members, a means for adjustably securing said telescoping members together, each said telescoping members having selectively displaceable axle contacting rods projecting outwardly therefrom, for measuring the distance between said axles on one side of said vehicle, and for comparing the distance between said axles on said other side of said vehicle, said axle contacting rods including rounded ends for contacting said axle.
It is another aspect of this invention to provide a method of aligning a plurality of axles on a trailer having a king pin comprising:                placing a bar each having a first and second coupler at one end thereof and a second end thereof under said trailer;        assembling said couplers around said king pin;        aligning said bars relative to said trailers so as to extend said other ends of said bars on either side of said trailer;        attaching an axle extender to each said sides of first said axle;        connecting a plurality of measured rods together on each side of said trailer so as to close the distance of said other end of said first and second bars and said axle extenders;        measuring said distance on each side of said trailer;        adjusting said first axle to substantially equalize said distances.
These and other objects and features of this invention shall now be described in relation to the following drawings:

Method and apparatus for tractor trailer axle wheel alignment


Methods and systems for controlling scheduling in a packet switching node in a network are provided which enable the scheduling of packets from different sources in an earliest deadline first order. The packets are assigned timestamp deadlines and placed in input queues. The timestamps are determined according to maximum delay or minimum throughput quality of service requirements specified for the packets. The packets are scheduled in the earliest deadline first order in an output packet store. The packet closest to its timestamp deadline is selected from the output packet store by using an index.

The present invention relates generally to packet communication networks and, more particularly, to scheduling of packets for transmission on a communication link.
Communication networks transmit different types of traffic, such as voice, data or video traffic. These different types of traffic generally have different quality of service (QoS) requirements. The QoS required by a type of traffic is often determined by the nature of the traffic. Voice traffic has low communication bandwidth requirements but is intolerant of delays or information arriving out of order. The same is also true of video traffic, but video traffic also requires much higher bandwidths. Data transfer has different characteristics. Data transfer usually occurs in bursts involving periods where little bandwidth is required, and then periods where very high bandwidths are required. Delay and order are largely irrelevant in data transfers, the primary requirement is often speed.
Asynchronous Transfer Mode (ATM) allows for different types of traffic to be carried using a single network. In practice ATM networks dynamically allocate network resources to meet the different qualities of service required by each of the different types of traffic being carried by the network.
ATM networks comprise a number of nodes connected by communication links. The nodes communicate by sending information in cells of 53 bytes along a predetermined path through the network. The predetermined path is referred to as a virtual circuit. When nodes wish to communicate, they tell the network the QoS they require from the virtual circuit. They do this by specifying such metrics as acceptable cell loss rate, minimum throughput, maximum jitter and maximum delay. The network establishes a virtual circuit if it can guarantee that the specified QoS parameters will be met.
ATM networks determine if specified QoS requirements can be met by predicting a path through the network that is likely to meet the requirements and then interrogating the nodes along that path to establish whether the nodes can accommodate the connection. The virtual circuit is established if all of the nodes along the connection route guarantee that the specified QoS requirements will be met. This method of allocating the resources of an ATM network ensures that the network provides the precise needs of a traffic stream provided they are within the network's capacity.
At each node in a network, schedulers are responsible for the order in which received cells from a variety of sources are transmitted on an outgoing communication link. One method used on scheduling packet transmission is an Earliest Deadline First (EDF) method. EDF schedulers assign each incoming cell a time by which it must be transmitted based on its QoS requirements. The scheduler then selects the cell that is closest to exceeding its deadline as the next outgoing cell.
Implementation of EDF schedulers poses difficulties, however. For example, some cells may have rate based requirements, while other cells have delay based requirements. Moreover, the scheduler should also be able to quickly determine both where a cell should be placed in a queue, and which cell in a queue should be transmitted at any time.

Time based packet scheduling and sorting system


A method and apparatus for determining information about a plurality of disk storage devices connected to an interrogating host computer through a disk drive controller employ, in one embodiment, an EVPD Inquiry command to obtain from a disk controller, connected to the interrogating host computer over a SCSI bus, the necessary information for devices which are not accessible to the interrogating host. The disk drive controller has sufficient capability to obtain the necessary information from the disk storage devices and format it for presentation to the host computer using standard VPD pages.

The invention relates generally to disk storage systems for controlling arrays of disk drives, and in particular, to a method for obtaining information, such as status information, about groups of the disk drives.
In a typical high speed disk array system, such as that manufactured by EMC Corporation under the name Symmetrix.RTM., the disk array system receives, from connected host computers, input/output (I/O) requests through an interconnection channel. In an open-systems environment, a typical channel is a SCSI channel, and the I/O requests are typically composed of read and write operations. Traditionally, these disk storage systems were passive storage systems making large amounts of magnetic disk storage available to The host computers connected to them. As the speed of the interconnections between the host and the disk drive arrays has increased, and as the arrays themselves, which can be controlled by a single disk controller, have both grown in size and become more intelligent, more information is available about the array and more information can be received and processed at the host computers, as well as at the disk drive controller, about the status of the system.
In those systems wherein a plurality of host computers connect to a single disk drive controller (the Symmetrix.RTM. controller for example) over a SCSI bus, a host has the ability to send a SCSI Inquiry command to the disk drive controller to obtain information about the devices to which that host has access. However, as graphical user interfaces (GUI's) develop for greater control of the disk drive system, as a whole, from a host computer, it becomes increasingly important for the controlling host computer to have as much information available to it as possible. Nevertheless, protocols, as the SCSI protocol, do not provide a mechanism for obtaining information about disk drives which are not available to the inquiring computer itself.
In particular, some mechanism is needed, in a SCSI environment, which enables a host computer to make inquiries of all or a group of disk drives, not all of which are normally accessible to the host. No mechanism exists in the SCSI command library, which is well defined, to perform that function. The closest; command is a standard Inquiry command, in which the host computer can obtain information about a designated disk drive to which it has access.

System for providing an interrogating host computer with group status information about disk devices including status information regarding disk devices not accessible to said host


In a photographing apparatus, while a deterioration of a contrast characteristic caused by an optical zooming operation is prevented, superior photographic images are continuously acquired. Magnification set by an optical zooming function is acquired, and a gamma curve, namely gradation correcting information is set to a gamma lookup table, while the gamma curve is applied during a photographing operation based upon the acquired set magnification. A gamma correcting unit corrects gradation of image data (namely, RAW data) outputted from an imaging element by employing gradation correcting information set in this gamma lookup table.

The present invention generally relates to a photographing apparatus, an image processing method, and a recording medium for recording an image processing program. More specifically, the present invention is related to such a photographing apparatus as a digital camera equipped with an optical zooming function, an image processing method employed in the digital camera, and a recording medium for recording thereon the image processing program, capable of improving contrast characteristics deteriorated in zooming magnification.
Among photographing apparatus such as digital cameras, some photographing apparatus are equipped with optical zooming functions. This optical zooming function corresponds to such a function that since a lens optical system is moved, a focal distance of this lens optical system is physically changed so as to be capable of changing an enlarging ratio of an image.
Conventionally, in a photographing apparatus equipped with such an optical zooming function, a contrast characteristic of a photographed image acquired at a wide terminal (wide angle side, namely under condition that focal distance becomes "shortest") is different from a contrast characteristic of a photographed image acquired at a telescopic terminal (telephotograph side, namely under condition that focal distance becomes "longest"). In particular, when zooming magnification becomes high, namely at the telescopic terminal (telephotograph side), a photographed image owns no contrast feeling, and therefore, is brought into such an image condition that a black image portion of this photographed image is floating. Such a phenomenon that a contrast feeling disappears is referred to as a "flare." This "flare" phenomenon is caused by lens characteristics of an optical system.
Very recently, since compact digital cameras are commercially available, there is such a trend that optical lenses mounted on these digital cameras are manufactured in smaller sizes. As a result, when zooming magnification is increased, the following problem may occur. That is, since the above-explained "flare" phenomenon is increased, contrast characteristics are considerably deteriorated.
In this connection as a method for correcting a brightness of an image, there is a method for controlling an exposure during a photographing operation. For instance, Japanese Laid-open Patent Application No. Hei-7-274062 discloses the following image exposure correcting method. That is, since the diaphragm/shutter mechanism is controlled in such a manner that the exposure amount obtained when the maximum Y signal (maximum luminance signal) is acquired may be nearly equal to 70 to 100% of the dynamic range of the CCD, the exposing control operation can be properly carried out under such a condition that a light photographic object may become lighter, whereas a dark photographic object may become darker.
However, the brightness correcting method described in the above-explained patent publication merely corresponds to an exposure correcting method. As a consequence, even though the brightness of the entire image can be adjusted, this brightness correcting method cannot avoid that the above-described contract characteristic is deteriorated due to the zooming magnification.
It should be understood that as a method capable of correcting a brightness of a photographed image, for instance, there is such a method for using specific software installed in a personal computer. However, this brightness correcting software method owns other problems, namely requirements of very cumbersome works. That is, a user is necessarily required to acquire photographed images into the personal computer. Also, while the user must confirm the brightnesses of the photographed images on the display screen, the user is required to fine-adjust the contrast of these confirmed images by performing a predetermined contrast adjusting operation in the manual manner.

Photographing apparatus, image processing method, and recording medium for recording image processing program, capable of improving contrast characteristics in high zooming magnification


A metal hydroxide complex has a formula Me(OH)4*A−*nH2O or MeO2*A−*nH2O. Preferred complexes are formed in an alkaline medium, and particularly especially preferred anions include cyanide and cyanide gold complexes. Contemplated complexes are formed on a metal hydroxide (e.g., hydrated zirconium, hafnium, and titanium hydroxide), which may be disposed in a porous container. Consequently, contemplated compounds may be used in methods of reducing the concentration of an anion in an alkaline medium.

Zirconium hydroxides and related compounds (e.g., titanium hydroxide, hafnium hydroxide) have been employed for isolation and/separation of selected ionic species under certain binding conditions, and depending on the particular ionic species, such compounds may have superior separation characteristics when compared to ionic exchange resins.
For example, U.S. Pat. No. 4,362,626 to Takeuchi et al. describes a preparation in which zirconium hydroxide is mixed with an epoxy resin, an unsaturated polyurethane, or polyethylene, and cured to form an adsorbent material. Takeuchi et al. use such materials to isolate phosphate anions from an aqueous solution at relatively highly acid pH (pH 3.0). Similarly, Echigo et al. describe in U.S. Pat. No. 4,576,969 an ion exchange resin in which a crosslinked phenolic resin encloses a water insoluble metal hydroxide, and wherein the inventors isolate cationic arsenic (As3+) from an aqueous medium at relatively acidic pH (pH 6.0).
In another example, as described in U.S. Pat. No. 5,578,218 to Matsuoka et al. the inventors utilize a polymeric resin that carries zirconium hydroxide to remove sulfate anions from a brine at relatively highly acidic pH (typically between pH 1.0-5.0, and preferably between 2.0 and 3.0). Alternatively, sulfate anions may be removed using zirconium hydroxide-coated activated carbon as described in U.S. Pat. No. 5,948,265 to Wakamatsu et al., and Shiga et al describe in U.S. Pat. No. 5,071,563 the use of a zirconium hydroxide slurry to bind sulfate wherein both, Wakamatsu and Shiga, employ relatively strong acidic conditions (e.g., pH 3.0-5.0) to bind the sulfate anion to their materials. Similar conditions and compositions are described to Joubert in U.S. Pat. No. 5,536,415.
In a still further example, as described in U.S. Pat. No. 6,238,544 to Oohara et al., iodine anions (e.g., iodate and periodate) are removed from an aqueous solution to be used for electrolysis by contacting the solution with a metal hydroxide under strongly acidic conditions (pH 3.0), wherein the metal hydroxide is (at least in some cases) disposed on a cation exchange resin. While most of the resin-metal hydroxide combinations may be particularly advantageous for column separation (e.g., desirable flow rates), the ion binding capacity of the metal hydroxide is often significantly reduced by the resin portion.
In order to circumvent at least some of the problems associated with reduced ion binding capacity of resin-bound metal hydroxides, Clarke et al. describe the use of metal hydroxides pastes and slurries for the removal and/or isolation of selected anionic species (arsenate, chromate, selenate, borate, fluoride, and perchlorate) under substantially neutral conditions (pH 6.0-7.5) using a layer of the metal hydroxide in a configurations with a high aspect ratio. In yet another example, as described in U.S. Pat. No. 4,855,059 to Frianeza-Kullberg, metallic cations (Ca2+ and Mg2+) are isolated from an alkaline aqueous solution using a metal hydroxide.
However, while most of the known metal hydroxide compositions and methods exhibit at least some advantage over other known materials to isolate cationic or anionic species from a medium, the pH of such media is generally limited to acidic (or at best neutral) pH.
Therefore, although there are numerous uses for metal hydroxides known in the art, all or almost all of them suffer from one or more disadvantages. Consequently, there is still a need to provide improved compositions and methods for metal hydroxides, and especially for adsorption of anions under alkaline conditions.

Compositions and methods for anion absorbent metal hydroxides


A plurality of vertical-cavity surface-emitting laser devices each having a different lasing wavelength are arrayed by a simple structure and a manufacturing process without increasing device resistance. Each vertical-cavity surface-emitting laser device comprises a layered structure including an active layer and a current confinement layer. The area of current confinement portion in the laminate structures is set corresponding to a wavelength of laser light emitted from each vertical-cavity surface-emitting laser device. Thereby, the plurality of vertical-cavity surface-emitting laser devices emits laser light with different lasing wavelengths.

1. Field of the Invention
The present invention relates to a vertical-cavity surface-emitting laser device array having layered structures such as a columnar mesa formed by laminating at least an active layer and a current confinement layer, and to a method of manufacturing the vertical-cavity surface-emitting laser device array.
2. Description of the Related Art
Conventionally, a vertical-cavity surface-emitting laser (VCSEL) device in which a layered structure laminating at least an active layer and a current confinement layer as typified in a columnar mesa structure is formed in an island shape has been generally used.
The columnar mesa structure is fabricated as follows. The layered structure is processed in a columnar shape having a mesa diameter of about 30 μm by dry etching or the like and then selectively oxidize the current confinement layer made of AlAs to provide a current confinement structure for efficiently injecting current into the active layer. Almost whole the columnar mesa structure is coated with an insulating film such as a dielectric film and part of the top of the mesa is selectively removed to form an aperture, thereby providing a ring electrode having a light output window.
The VCSEL device has a preferable characteristic as a light-emitting device. That is, because of the presence of the current confinement layer, current is efficiently injected into the VCSEL device, so the VCSEL device can oscillate laser efficiently.
The main structure of the VCSEL device can be arrayed two-dimensionally on a surface of, for example, silicon wafer, therefore this is suitable for an array essentially. The lasing wavelength of the VCSEL changes depending on mainly its structure, particularly a layer thickness around the active layer corresponding to a cavity length. In general, the film thickness distribution of an epitaxially grown film is extremely small, for example 0.5% or less, so the lasing wavelength of the VCSEL hardly changes in the same wafer. The transverse mode of the VCSEL is defined corresponding to the structure of the active layer, the oxidized confinement portion, the light output window of the electrode and so on. The lasing threshold and the lasing wavelength are the same value in the same mode. Therefore, when arraying a plurality of VCSEL devices on one substrate, the lasing wavelength of each VCSEL device constructing the array can conform to each other.
However, in the field requiring large information transmission quantity such as optical communication and optical wiring, it is desirable that the lasing wavelength of each VCSEL device constructing the array differs from each other to realize a so-called WDM (Wavelength Division Multiplexing) transmission.
As a method for controlling the lasing wavelength of the VCSEL, a method using a micro cavity utilizing a movable solenoid, a method changing the film thickness of the active layer by selective growth, a method changing a columnar diameter of micro mesa (refer to Japanese Unexamined Patent Application Publication No. H11-220206) and so on have been proposed.
However, the above-mentioned conventional methods have problems as described below.
In case of using a movable solenoid, the control of the solenoid is required in addition to the laser, and the wavelength is unstable.
In case of using selective growth, the growth is required twice, so the process becomes complicated. In addition, there is a problem that a steepness of a boundary of a DBR (Distributed Bragg Reflector) layer is lowered due to two-times epitaxial growth.
In case of changing the mesa diameter, an electrode contact area and mesa volume are small. This increases device resistance and causes a problem that it is difficult to realize a high output VCSEL device.

Vertical-cavity surface-emitting laser device array and method of manufacturing the same


An industrial truck (1) has a drive section (2) and a load section (4) movable relative to the drive section (2). The load section (4) has at least one wheelarm (5) having at least one load roller (6). The load roller (6) is rotatably mounted in a load roller carrier (12) swively-mounted by a swivel bearing (13) on the wheelarm (5). In the vicinity of the swivel bearing (13), on the upper side of the wheelarm (5), there is an entry guide (20). The guide (20) includes at least one roller (21; 22; 23; 24) rotatably mounted on the wheelarm (5) and projecting upwardly beyond a load-bearing surface (LF) of the wheelarm (5). The swivel bearing (13) of the load roller carrier (12) includes a bearing pin (25). The at least one roller (21; 22; 23; 24) is rotatably mounted on the bearing pin (25).

Field of the Invention
This invention relates to an industrial truck, in particular a lift truck, with a drive section and a load section that can be raised and lowered relative to the drive section. The load section has at least one wheelarm which is provided with at least one load roller. The load roller is mounted so that it can rotate in a load roller carrier and the load roller carrier is swively-mounted by a swivel bearing on the wheelarm.
Description of Related Art
Industrial trucks with wheelarms are used to lift a pallet by driving the wheelarms under the pallet and then lifting the wheelarms to lift the pallet. For this purpose, the load section is raised or lowered relative to the drive section. Load roller carriers in which the load rollers are mounted are actuated by a system of levers and a linkage and can thus be swiveled outwardly and downwardly or inwardly and upwardly to raise or lower the wheelarms, respectively. On low-lift trucks or order pickers, a lifting movement of this type is called a low-lift, while on high-lift trucks with an additional lifting frame, it is called the initial lift.
Lift trucks with load rollers located on the wheelarms in pivoting load roller carriers, which are actuated by means of a linkage and a system of levers, are described, for example, in EP 1 690 823 B1 or DE 10 2009 033 709 A1. Conventional lift trucks are designed for the handling of standardized "euro pallets", which have an entry height for the wheelarms of 100 mm and, for this purpose, the trucks have a wheelarm height of the wheelarms in the fully lowered position of approximately 85 mm.
With the wheelarms in the lowered position, the wheel arms can be inserted into the pickup openings of a pallet on the ground or floor. On pallets, in particular special pallets with a lower entry height of the pickup openings than on standard euro pallets, the upper sides of the wheelarms can slide along the underside of the pallet. The upper sides of the wheelarms form the load-bearing surface with which the pallet is picked up and lifted. Thus, when the wheelarms are inserted, a great deal of friction occurs under the pallet and, therefore, a great deal of force is required to push the wheelarms into the pallet. Under some conditions, the pallet can be damaged. Damage can occur in particular if the pallet is sagging under a load or is damaged, and thus the entry height of the pickup openings of the pallet, which is the distance from the surface of the road to the underside of a load bearing surface of the pallet, is reduced.
Therefore, it is an object of the invention to provide an industrial truck of the general type described above but which can be driven safely and with a small amount of force under pallets which have a low entry height.

Industrial truck with load rollers located on load roller carriers on a wheelarm


A RAID class driver model enables users to easily combine two or more disks into a bootable RAID system without specialized disk controllers and allows the creation of RAID systems using disks of different types, controllers, and interfaces. A RAID class driver is initialized in response to the identification of a RAID controller. Disk controllers return RAID-specific device identifications, rather than a standard disk device identifications, for each disk to be included in the RAID system. The RAID class driver binds a RAID-specific functional interface to each disk having a RAID-specific device identification and combines the disks into a disk object representing the entire RAID system. The disk object provides the operating system with a standard disk device identification. The operating system loads a standard disk driver to interface with the disk object, thereby enabling transparent access to the RAID system.

The present invention relates to the field of data storage devices. Computers often store large quantities of data, including data such as music, video, games, applications, and other valuable information, on hard disk drives and other data storage devices, which are referred to herein generally as "disks". As users' storage needs increase and the price of disks fall, computers often employ multiple disks to meet their storage needs.
To improve performance, reliability, and efficiency in using multiple disks for data storage, two or more disks can be combined into a single "logical" disk. One common disk architecture for combining multiple disks is RAID (Redundant Array of Independent Disks). Although RAID systems can provide improved disk performance and/or reliability, RAID systems are complicated to set up and configure. Additionally, RAID systems typically require specialized disk controllers and driver software. Thus, RAID systems are typically too expensive and too difficult for use by most computer users.
Additionally, because some current RAID systems require specialized disk controllers, they are limited in the number and type of disks that can be combined. For example, it is virtually impossible for current RAID systems to combine an EIDE disk and a SCSI disk in the same RAID system. In other RAID systems, the computer operating systems combines disk partitions, rather than the underlying disk itself, to create the RAID system. Because disk partitions are defined by the operating system, the disk partitions, and hence the entire RAID system, are inaccessible until the operating system has loaded. Thus in these implementations, the computer cannot be booted from the RAID system.
It is therefore desirable for a system and method to enable users to easily combine two or more disks into a bootable RAID system without specialized disk controllers. It is further desirable to be able to create RAID systems using disks of different types, controllers, and interfaces.


There is disclosed a mobile terminal including a front case, a first rear case shaped to cover a first area of a rear surface of the front case, a second rear case shaped to cover the second area of the rear surface of the front case, a tightening groove formed in the portion where the first rear case and the second rear case are coupled with each other and comprising inclined surfaces a first tightening rib projected from a front surface of the first rear case and comprising an inclined surface corresponding to one inclined surface of the tightening groove, a second tightening rib projected from the front surface of the second rear case and comprising an inclined surface corresponding to the other inclined surface of the tightening groove, wherein the first tightening rib and the second tightening rib are inserted in the tightening groove.

Field of the Disclosure
Embodiments of the present disclosure relate to a display panel which may display an image on a predetermined area of a display unit and a mobile terminal including the same.
Background of the Disclosure
Terminals may be generally classified as mobile/portable terminals or stationary terminals according to their mobility. Mobile terminals may also be classified as handheld terminals or vehicle mounted terminals according to whether or not a user can directly carry the terminal.
Mobile terminals have become increasingly more functional. Examples of such functions include data and voice communications, capturing images and video via a camera, recording audio, playing music files via a speaker system, and displaying images and video on a display. Some mobile terminals include additional functionality which supports game playing, while other terminals are configured as multimedia players. More recently, mobile terminals have been configured to receive broadcast and multicast signals which permit viewing of content such as videos and television programs.
As such functions become more diversified, the mobile terminal can support more complicated functions such as capturing images or video, reproducing music or video files, playing games, receiving broadcast signals, and the like. By comprehensively and collectively implementing such functions, the mobile terminal may be embodied in the form of a multimedia player or device.
Importance of wireless communication techniques is increasingly emphasized to gain contents easily. The mobile terminal includes various types of antennas so as to receive and transmit data in manners of diverse radio systems. An antenna is loaded in a rear case of the mobile terminal and the portion having the antenna is fabricated in a different way from the other portion of the rear case. The portions are formed of different materials independently and they are then coupled to a front case.
The rear case configured of two pieces has a predetermined gap and this gap deteriorates an exterior appearance. The two pieces are fabricated independently so that fabrication errors can be increased and that the rigidity between the two pieces can become weak disadvantageously.


Methods and systems are disclosed for a virtual mobile service provider. In one embodiment, a method comprises providing a first mobile service enabler for a first mobile service, the mobile service enabler having a first interface using a first format for communicating with a first set of content providers; and providing a second mobile service enabler for a second mobile service, the second mobile service enabler having a second interface using the first format for communicating with a second set of content providers. The method further comprises providing a plurality of drivers, each of the drivers configured to adapt communications received from the first and second mobile service enablers to a wireless network communications format associated with a wireless network access provider in communications with the respective driver.

The present invention relates generally to mobile applications and mobile services. More specifically, embodiments of the invention allow for a virtual aggregation of mobile enablers, supporting functions, drivers and signaling that can be performed across different mobile network operators or different access networks.
While there is much hype about the potential of mobile devices and mobile applications to dramatically change the business world as we know it today, the fact of the matter is mobile applications have not been widely adopted by enterprises. Several reasons for the lack of adoption include security concerns, total cost of ownership for an enterprise to provision, support and manage a fleet of mobile devices and the impossibility to manage integration and agreements with a wide variety of mobile network operators (MNOs) thereby limiting the effective area of use for many mobile devices. Thus, despite recognizing a value and need for mobilizing a workforce, these factors combine in a manner that makes it difficult for an enterprise's information technology (IT) department to accurately identify the total cost of ownership and the return on investment associated with deploying such devices throughout the entire organization.
These same issues also limit the capability of third parties that develop applications for the mobile market. Such third parties need to repeat integration processes and reach agreements with multiple mobile network operators in order to ensure the largest possible market and ensure that each MNO supports roaming features for the third party's applications. Moreover, as different MNOs role out new mobile enablers (e.g., location services, mobile payment services, etc.), third party developers need to update their applications to support the new enablers for each MNO.
Despite the difficulty associated with integrating new mobile enablers into third party applications, MNOs are in a particularly competitive market that requires new features to be implemented on a regular basis or the MNO will not appear competitive within the marketplace and may lose market share to other MNOs who regularly adopt new features/enablers. Implementing new enablers is time consuming and expensive. Thus, the investments MNOs must make in order to "remain competitive" may be jeopardizing their financial health and future. The problem is exacerbated by the fact that many enterprises are slow to adopt mobile services due to the problems discussed above.


In one aspect, the invention provides a method for tracking a mobile terminal. In some embodiments, this method includes the following steps: receiving a signal transmitted from the mobile terminal; searching a primary search area for a signal associated with the mobile terminal; searching a secondary search area for a signal associated with the mobile terminal, wherein the secondary search area is larger than the primary search area; determining the strength of a signal associated with the mobile terminal that was found by searching the secondary search area; and determining whether the primary search area should be modified based on the determined strength of the signal that was found by searching the secondary search area.

In order to maintain air interface synchronization between a terminal (e.g., a mobile phone) and a base station, as well as to demodulate a radio signal transmitted by the terminal, the base station typically uses a tracking mechanism to follow the paths of a signal transmitted by the terminal. The tracking mechanism typically tracks the terminal within a defined search area (a.k.a., window).
When handing off a terminal connection from one base to another base station, the base station to which the connection is being handed off typically searches for signal paths associated with the terminal over the entire range of the base station. After the base station finds a signal path, the base station tracks the terminal by searching a much smaller search area than was used to initially locate the terminal.
In some radio access networks, a "reflected" signal could be stronger than a direct signal. For example, a signal transmitted from a repeater or relay or a signal bouncing off of a mountain or other structure may be stronger than the original signal transmitted by the terminal. Typically, there is a large timing difference between the direct signal and the reflected signal.
Using the repeater case as an example, a terminal moving away from the base station towards the repeater is tracked by the base station to maintain air interface synchronisation. At some point, from the base station's perspective, the strength of the signal received from the repeater will be larger than the strength of the signal received directly from the terminal. The timing difference is usually large between the direct signal being tracked and the "reflected" signal (i.e., the signal transmitted by the repeater). If the timing difference is larger than can be handled by the tracking mechanism and its window size, the base station tracking mechanism will not be able to include the stronger signal from the radio repeater. The strong signal from the radio repeater will instead contribute to the received noise, and reduce the signal to noise ratio.
What is desired are systems and methods for overcoming this problem.

Systems and methods for tracking power peaks of a signal