Disclosed is a portable security device and method for detection and treatment of computer malware. An example method includes performing a malware detection experiment by the security device on the computer by simulating a connection to the computer of a simulated data storage device containing a predefined set of data. The method further includes determining if there are any modifications in the set of data contained in the simulated data storage device after termination of the malware detection experiment. The method further includes, based on whether there are any modifications in the set of data, determining whether to perform one or more subsequent malware detection experiments by the security device on the computer. In one example aspect, each of the one or more subsequent malware detection experiments are configured to simulate a different connection to the computer of a different simulated data storage device containing the predefined set of data.

The popularity of computer and network technologies has been rapidly growing for the past two decades; however, it has been accompanied by a steady growth in cybercrime, which ranges from relatively harmless cases, such as distribution of unsolicited e-mail, commonly known as spam, to more serious cases of cybercrimes, such as denial of service attacks, stealing of confidential financial information, and even cyber warfare and terrorism. It has become obvious that it is imperative to aggressively combat cybercrime. And, one of the most commonly used means for protecting computers from cyber attacks is antivirus software. However, current generation of antivirus software solutions has shortcomings.
Antivirus applications are generally resource intensive, which has detrimental effect on the productivity of computers on which they are deployed, especially during performance of frequent and complex antiviral tasks. Examples of such tasks are checking hard disk for malware, which significantly loads computer's disk system, and frequent updates of antivirus databases, which consumes network bandwidth. The consumption of processing resources by antivirus application especially affects personal computers (PCs), notebooks and other types of computers that have limited processing capabilities. It has been observed by the inventors that the processing load on such computers can be reduced if the antivirus application is run from a separate device, which can be connected to the computer to perform antivirus testing tasks.

Security devices and methods for detection of malware by detecting data modification


According to the present invention, there is provided a method of recording a unique ID to a read-only optical disc based on the 17PP modulation. The read-only optical disc (1) has set thereon a specific physical cluster to which a unique ID is to be recorded. With user data to be recorded to the specific physical cluster being made all zero (0), a pit/land pattern is formed, and a molding machine using a molding die is used to form many optical discs in the common manner. Thereafter, an ID unique to each optical disc is generated, and a land in a predetermined position in the specific physical cluster is transited to a pit by irradiating high-power laser light to the land correspondingly to the bit information, so that the pit/land pattern will comply the 17PP modulation rule even after the transition of the land to the pit.

As the information recording medium on which copyrighted work information such as a piece of music, image, etc. can be recorded in a digital form, there are widely known read-only optical discs such as a CD (compact disc), DVD (digital versatile disc) and the like.
Copyrighted work information can be recorded on an optical disc such as a CD or DVD by forming, on a disc-shaped substrate of the latter, a land/pit pattern corresponding to a digital form of the copyrighted work information. A disc master having such copyrighted work information thus recorded thereon can be replicated to produce and sell a large number of optical discs carrying the same copyrighted work information.
So, in marketing such optical discs, it is necessary to prevent the optical disc from being illegally copied and the copyright on work information recorded on the optical disc from being infringed. However, since read-only optical discs are designed to have only same information recorded thereon, they cannot be differentiated from each other. That is, the read-only optical disc is not necessarily desirable from the standpoint of medium management.
As a solution to the problems in the medium management of the optical discs, there is available a method of additionally recording medium-unique information different from one medium to another on a part of each read-only optical disc. By additionally writing medium-unique information to each medium, it is possible to build a system in which a disc player reads the medium-unique information on an optical disc and which sends it to a server via a network. In case illegal copies of an optical disc having copyrighted work information recorded thereon are produced and marketed without permission of the copyright holder, many pieces of the same medium-unique information will be detectable by such a system via the network, by which it is alarmed that the illegal copies of the optical disc in consideration are on the market. Further, the detected medium-unique information can be traced to ascertain a person having illegally copied the optical disc without permission and also prevent such illegal copying. Recording of such medium-unique information on each read-only optical disc can be a very effective solution to the problem of such an illegal copying of a read-only optical disc.
Even a piece of medium information unique to each title of work information recorded on an optical disc will be useful to protect the copyright on the work information as long as it is recorded in such a manner that it cannot easily be copied by any commercially available recorder/player.
It is well known to utilize the "Postscribed ID (trademark)" developed by the Sony and Sony Disclosure for additionally writing an Identifier unique to each optical medium to a portion of the optical disc where work information as a content or the like is recorded in the form of a land/pit pattern.
The method utilizing the "Postscribed ID" will be explained herebelow. An optical disc such as a CD of which the reflecting layer as a recording layer is formed from a material that can be melted by additional-writing light is produced once. Next, a land in a predetermined portion of a land/pit pattern formed on a recording track of the optical disc is concaved, namely, transited to a pit by irradiating a high-power laser beam.
An area where the land may be transited to a pit is provided in a plurality of predetermined portions on a read-only optical disc, it is decided based on information unique to the optical disc whether each of the land portions is to be transited to a pit or left as it is, and the unique disc information is additionally written in the area where actual work information as a content or the like is recorded.
In case the above Postscribed ID is utilized, since it is necessary that a location where the Postscribed ID is recorded should be detectable by a player for the optical disc, the portion of the optical disc where a land is transited to a pit should be limited to a predetermined portion of the optical disc. Further, if a data row that will not comply with a modulation rule after the land is transited to a pit, the optical disc will not be playable. So, it is necessary to abide by the modulation rule also after the land is transited to a pit.
A recording rule having solved the above problems with a CD or DVD adopting the EFM (eight-fourteen modulation) or EFM+technique is disclosed in the Japanese Patent Application Laid-Open Disclosure No. 2003-141742 and Japanese Patent Gazette No. 2003-151145.
Recently, there has been proposed a BD (blue-ray) disc (will be referred to as "BD disc" hereunder) as a recording medium of a generation next to the CD and DVD. A read-only BD disc should desirably have an Identifier additionally recorded thereon with an Identifier recording technique such as the aforementioned Postscribed ID.

Optical disc manufacturing method and device, optical disc, and optical disc reproduction method


A system comprises an infrastructure element including a computer programmed to communicate with a first stationary communication node having a first directional short-wave antenna with a first field of view and a second stationary communication node having a second directional short-wave antenna with a second field of view. The first communication node is located within the second field of view. The computer is programmed to determine a first and a second transmission parameter for the first and second stationary communication node respectively based on received object detection sensor data including object data from a respective field of view of each communication node's directional antenna. Each of the first and second transmission parameters includes a transmission power and/or a data throughput rate. The computer is programmed, based on received communication metrics from the first communication node, to determine a deficiency of the second communication node, and upon determining the deficiency of the second communication node, to actuate the first communication node to provide coverage for the second field of view.

A vehicle can receive messages, e.g., from a stationary infrastructure element, via one or more wireless communication networks and/or protocols, e.g., providing what can be referred to as V2X communications (vehicle-to-everything communications which can include vehicle-to-vehicle and vehicle-to-infrastructure communications). Data shared via V2X communications from the infrastructure element can include data about a weather condition, traffic condition, an ongoing roadside assistance, etc. However, if infrastructure components such as computer(s) or antenna(s), etc., are impaired, data may not be relayed with an acceptable level of quality.

Vehicle-to-infrastructure communication control including node deficiency determination


Wastewater lagoons are treated with chlorine oxygen compounds to react with odorous sulfides and mercaptans emanating from the lagoon. A fine spray of an aqueous solution of the chlorine oxygen compound (HOCl, NaClO.sub.2, or NaOCL) is applied over the lagoon. The chlorine oxygen compounds react with the sulfides in the vapor zone above the lagoon, converting the odorous compounds to non-odorous compounds.

This invention relates generally to odor abatement in wastewater in anaerobic digestive lagoons. In one specific aspect, the invention relates to a method of treating wastewater lagoons using a fine spray of an aqueous solution of a chemical to react with the odor vapors emanating from the lagoon surface, converting the odors (e.g. H.sub.2 S and mercaptans) to non odor compounds.
Many industrial plants utilize lagoons (e.g. ponds) to stabilize and equalize wastewaters. By collecting and storing wastewaters in lagoons the biochemical oxygen demand (BOD) of the water is reduced. BOD is a means of estimating the degree of biodegradable contamination of wastewater. It is the amount (mg/liter) of oxygen required during stabilization of the decomposable organic matter by biochemical action. Storage of wastewater for relative long periods of time, typically 1 to 30 days, reduces the BOD and thus improves the quality of the effluent water. The stabilization can be accelerated by aeration in aerobic digestive systems.
The size of wastewater lagoons vary considerably, but generally cover from 1,000 square feet to several million square feet.
The most common source of odors in wastewater is reduced sulfur compounds such as H.sub.2 S and mercaptans which result from the anaerobic (bacteria) decomposition of biodegradable organic matter in the presence of sulfates. In aerobic digestive systems, odor generally is not a problem. The present invention is, accordingly, directed specifically to the treatment of anaerobic digestive systems.
The present methods of chemically treating wastewater for odor reduction include (a) aqueous treatment with an oxidant such as potassium permanganate; (b) chlorination of wastewater liquids with a chlorine compound such as elemental chlorine, sodium of calcium hypochlorite, or chlorine dioxide; and (c) ozoning. All of these systems are economically impractical for large lagoons.


A blocking section is inserted between the control section and the fuse section of a fuse control logic circuit. The blocking section comprises switching means which block the flow of DC current during a power-up sequence and thus avoids the collapse of the power supply voltage with the attending potential for incorrect addressing and improper function and timing options. The insertion of the blocking section further eliminates indeterminate logic states when fusible means are not fully blown thus assuring correct voltage levels at the output of the circuit.

1. Field of the Invention
The invention relates to an address matching circuit for redundancy cell repair in DRAM memories, and more particularly to such a circuit which is without a DC path at power up and one which has a better margin when the fuse in the circuit is only partially blown.
2. Description of the Related Art
Referring now to FIG. 1a a conventional fuse control logic circuit 10 is shown. Power-up signal PU is the input to control section 12 and couples to the gate of PMOS transistor P2. Transistors P1 and P2 are coupled in parallel between a power supply VCC and a common node P2D. The fuse section 14 with fuse I1 is coupled between P2D and the return terminal of power supply VCC (ground in FIG. 1a). The common node P2D couples to the gates of PMOS transistor P3 and NMOS transistor N1 of driver section 16. Transistors P3 and N1 are coupled in series between VCC and the return terminal of power supply VCC (ground). The junction between transistors P3 and N1 is the output terminal OUT of driver section 16. The output terminal OUT also feeds back to the gate of PMOS transistor P1.
The problem with the related art of FIG. 1a is that it has a DC path when PU=0 (logical "0"), which is the power-up state. This will introduce potential problems such as excessive current drain if there are many of these circuits, especially when the driving capability of the power supply is not enough. An additional problem is that the related art circuit has a smaller margin for normal function if fuse I1 is not perfectly blown because transistor P2 represents a large resistor for a small DC current. Common node P2D will then be at some intermediate voltage level depending on the resistance of fuse I1. As a result the circuit may malfunction because the voltage at common node P2D is not high enough. Additionally, there may be DC current flowing through transistors P3/N1. This is a serious problem for low power memories which may be out-of-spec then.
The related art circuit 11 of FIG. 1b is structurally similar to circuit 10 of FIG. 1a but uses NMOS transistors. Fuse section Block 14 is coupled between power supply VCC and node N2D. Block 22, coupled between node N2D and ground comprises transistors N21 and N22. The first input of Block 22 receives power-up signal PU-bar, which is the inverted signal of PU of circuit 10, Block 12. Block 26, showing a generic inverter INV, is coupled between node N2D and the second input to Block 22. The description for FIG. 1a above applies equally to circuit 11 of FIG. 1b.
FIG. 2 is a graph of the input signal and the voltage levels of a good power supply or regulator during power-up of the circuit of FIG. 1. Curve 21 depicts the external VDD supply ramping up, Curve 22 depicts the power-up signal PU ramping up briefly to Point A, dropping to "0" level, and then rising at Point B to join Curve 21. Curve 23 depicts the internal VCC supply ramping up smoothly.
FIG. 3 is a graph of the input signal and voltage levels of a bad power supply or regulator of the circuit of FIG. 1. Curves 31 and 32 are identical to Curves 21 and 22 of FIG. 2. Internal VCC Curve 33, however, ramps up only to about Point A, then continues almost horizontally to Point C and then rises. The section from near Point A to Point C represents an excessive current draw caused by DC paths in the P2/I1 path in other circuits without blown fuses. This delay in the rise of the internal VCC supply causes problems when the blown-fuse initialization time is not long enough, because then common node P2D cannot set up properly at startup and its voltage level is at an indeterminate state. An improper address may be output or an improper function/timing option may be selected. Conversely, if the initialization time is lengthened it affects other circuits which use the power-up signal PU and VCC for initialization. Lastly, in blown fuse circuits a DC current path can be introduced in the P3/N1 transistor path because P2D is neither at "0" nor at "1".
An improved circuit and method are clearly needed to overcome these problems of the related art. The circuits and method described hereinafter and illustrated in FIGS. 4a, 4b, 5a, 5b, and 6 completely eliminates these problems.
U.S. Pat. No. 6,292,422 (Pitts) discloses a system and method for storing data values by implementation of electrical fuse chains which enables the programming and use of electrical fuses and includes read and write protection. U.S. Pat. No. 6,073,258 (Wheater) teaches the use of fuse elements responsible for soft-fusing redundant memory elements into the memory array. Soft-fusing is defined to mean that the fuse elements may be set and reset via an electronic signal.
It should be noted that none of the above-cited examples of the related art address the above described problems.

Low power design for fuse control circuit


The present invention relates to an apparatus for brewing hot beverages, and more particularly to an apparatus for automated brewing of coffee or tea. The apparatus for automated brewing of coffee comprises a frame structure defining an interior space, wherein the interior space houses a ground coffee feed system, a carousel assembly, a water system, a waste system and a coffee storage and dispensing system.

Currently, most commercial establishments selling coffee use standard commercial drip coffee machines which include glass urns that brew 59 ounces of coffee.
Drip coffee is brewed manually, and every brew requires fresh ground coffee to be filled into a paper filter which is placed into a brew basket, and then mounted into the drip coffee machine. Once the brew basket is securely in place, the brewing cycle is activated by pressing a brew button. After brewing is complete, the brew basket must be removed from the drip coffee machine and the coffee grounds and filter discarded into the garbage. The brew basket urn is then rinsed and the process is repeated for another brewing cycle.
This process is extremely tedious and demanding, especially during peak business hours, making it difficult to consistently control the quality level of coffee while ensuring consumers are being served in a hospitable manner.
This brewing process has been unchanged for the past 30-years and is currently used today although population has increased as well as the consumption of coffee. The average amount of coffee sold at an establishment during a 17-hour day is approximately 19,353 cups of coffee (15 ounce cup), and 50% of the cups are sold within a five hour window, typically between 6 am until 11 am.
Larger coffee brewers are available that can brew greater quantities, but due to the limited amount of space available in coffee shops this option is not generally feasible. Additional concerns, include, (1) compromised coffee quality, loss of favourable flavour, appropriate heat, and freshness during non-peak hours since the brewed coffee should be consumed within a certain amount of time to ensure a true quality of freshly brewed coffee and to avoid staleness; (2) larger brew basket present difficulties for staff to use safely, and often lead to staff getting burned from spillage of the hot brewed coffee.


A rotary piston and cylinder device (1) comprising a rotor (2), a stator and a shutter disc (3), the rotor comprising a piston (5) which extends from the rotor into the cylinder space, the rotor and the stator together defining the cylinder space, the shutter disc passing through the cylinder space and forming a partition therein, and the disc comprising a slot (3a) which allows passage of the piston therethrough, the slot provided between two surface portions which receive the piston therethrough,at least one of the surfaces defines a close-running region with the piston to provide a fluid seal, and for at least part of the period during which the piston passes through the slot, the close-running region is offset from a mid-plane which extends through the disc and is co-planar with the disc.

Rotary piston and cylinder devices can take the form of an internal combustion engine, or a compressor such as a supercharger or fluid pump, or as an expander such as a steam engine or turbine replacement, and also as a positive displacement device.
A rotary piston and cylinder device comprises a rotor and a stator, the stator at least partially defining an annular cylinder space, the rotor may be in the form of a ring, and the rotor comprising at least one piston which extends from the rotor into the annular cylinder space, in use the at least one piston is moved circumferentially through the annular cylinder space on rotation of the rotor relative to the stator, the rotor being sealed relative to the stator, and the device further comprising cylinder space shutter means which is capable of being moved relative to the stator to a closed position in which the shutter means partitions the annular cylinder space, and to an open position in which the shutter means permits passage of the at least one piston, the cylinder space shutter means comprising a shutter disc.
The term 'piston' is used herein in its widest sense to include, where the context admits, a partition capable of moving relative to a cylinder wall, and such partition need not generally be of substantial thickness in the direction of relative movement but can be in the form of a blade. The partition may be of substantial thickness or may be hollow. The shutter disc may present a partition which extends substantially radially of the cylinder space.
We have devised improved sealing arrangements for such devices.
The geometry of the interior surface of the rotor is governed by at least part of the outer face of the rotating shutter disc that allows the piston to pass through an aperture at the end of a stroke. The piston has to pass through the disc preferably once in each cycle, while forming at least a partial seal to both the cylinder wall and aperture in the disc, as the chamber still contains the working fluid and in most configurations is still connected to the outlet port (in a compressor), or more generally to the volume at working pressure. It should be noted that where the term seal is used, we include the meaning of an arrangement which reduces the clearance, minimising leakage, and not necessarily completely preventing fluid transfer across the seal.
The solution apparent to one skilled in the art is to prioritise the sealing on the working face of the piston, by defining a close running geometry at a mid-plane of the disc. The close-running geometry can be formed of a set of points, or preferably a continuous line which may be curved or straight. The working face of the piston can be defined from this close-running geometry, taking into account the relative motions of the disc and rotor. It can be seen that this approach will result in a piston and disc that will maintain a substantially constant and minimal clearance at the close-running line throughout the passage of the piston through the disc. To each side of the close-running line, with respect to the thickness off the disc, the working face of the blade will be a variable and substantially greater distance away from the surface of the aperture in the disc.
One method to create the blade and aperture geometry as described above is to first also define a close-running geometry for the opposite face of the piston, which can have a larger clearance as it is less critical. The close-running geometry is then swept along the rotor within its coordinate system to form the piston surface. The aperture is then formed by sweep-cutting the disc using the same sealing cross-section within its coordinate system. The lead-in and lead-out surface regions each side of the sealing plane are then formed by sweep-cutting the disc using the leading and trailing edge cross-sections of the piston, within the disc coordinate system. An example of such an arrangement is shown in FIGS. 1A to 1D, which show an end on view of a piston blade 103 passing through a slot 102 in a shutter disc 101, viewed through a wall of the rotor, which is omitted for clarity. The close-running line, CRL, lies on a (mid-) plane 105 which is central of the shutter disc relative to the depth/height of the circumferential surface 101a which is (at some point in time) in close co-operation with the rotor. In this arrangement, the close running line remains in this position as the (blade) passes through the slot. As can be seen from the Figures, the leading and trailing edges pass through different regions of the volume of the slot 102. In particular, 'face a' initially passes substantially closer to the lower region of the slot, and then substantially closer to the upper region of the slot. It will be understood that in other embodiments of the device, this can apply in the opposite sense. In this particular embodiment, this leads to a gap between the piston and shutter disc before the leading edge of the piston reaches the CRL. This gap can allow leakage of fluid out of the cylinder, depending on the configuration of the device.
It will be understood that various methods of forming suitable disc slot geometries are possible, and that embodiments of the present invention may be realised by any suitable method that results in the required geometry. Moreover, a piston shape could be realised based on a given slot configuration, as opposed to vice versa, and thereby achieving a suitable slot/shutter disc interface.
An aim of the present invention is to provide a preferred arrangement of the sealing interface between blade and shutter disc aperture. "Sealing interface" refers broadly to the faces of the piston and disc aperture, and "close-running region/line" refers to the set of points of the disc that represent a substantially minimal sealing gap at the sealing interface, between a working face of the blade and disc aperture. The close-running line may be formed of multiple discrete sections, but is preferably a single continuous line.


A method and apparatus for shifting a dynamic circuit, driven by a one-shot clock, to a pre-charge mode, during a power-off mode, is provided. Under certain conditions, a floating node may be present in a dynamic circuit. One approach to prevent floating nodes involves the generation of a new one-shot clock signal that is supplied to the last dynamic circuit in the series of dynamic circuits before the output flop (“the final dynamic circuit”). The new one-shot clock signal is driven to a logical low value when the power-off signal has a logical high value. Another approach to prevent floating nodes involves modifying the final dynamic circuit to include a structure that, when the power-off signal has a logical high value, drives the dynamic node to either a logical high value or a logical low value to prevent the dynamic node from becoming a floating node.

A circuit may be categorized as being a static circuit or a dynamic circuit. A static circuit is a circuit whose output is not triggered by a clock signal. On the other hand, a dynamic circuit is a circuit whose output is triggered by a clock signal. An advantage of dynamic circuits is that they typically operate faster than static circuits.
Since the output of a dynamic circuit is triggered by a clock signal, a dynamic circuit operates in two different modes, namely an evaluation mode and a pre-charge mode, depending on whether the value of the clock signal is a logical high (in other words, a "1") or a logical low (in other words, a "0").
When the clock signal applied to the dynamic circuit has a logical high value, the dynamic circuit is in evaluation mode. In evaluation mode, the logic of the dynamic circuit is evaluated using the inputs to the dynamic circuit. Thus, when a dynamic circuit is in evaluation mode, the output of the dynamic circuit depends upon the evaluation of the logic of the dynamic circuit using the inputs applied to the dynamic circuit.
When the clock signal applied to the dynamic circuit has a logical low value, the dynamic circuit is in pre-charge mode. In pre-charge mode, the logic of the dynamic circuit is not evaluated. The output of a dynamic circuit in pre-charge mode is driven to a logical low value, since the logic of the dynamic circuit is not being evaluated.
FIG. 1 is a diagram illustrating the output signal of a dynamic circuit in both evaluation mode and pre-charge mode. As FIG. 1 illustrates, the rising edge of the clock signal causes the dynamic circuit to be in evaluation mode, while the falling edge of the clock signal causes the dynamic circuit to be in pre-charge mode. Thus, the evaluation of the logic of a dynamic circuit, using the applied inputs, is triggered by the rising edge of the clock, and the output of the dynamic circuit is driven to a logical low at the falling edge of the clock.
A dynamic circuit may be used in conjunction with an input flop and an output flop. A flop (alternately called a "flip-flop") is a type of circuit that will maintain its state indefinitely until it receives an input signal, called a trigger, which forces the flop to alternate its state. Once the flop changes state it remains in that state until another trigger is received. A flop may be used to store data. A flop that provides a set of inputs to a dynamic circuit is referred to as an input flop, while a flop that stores a set of outputs from a dynamic circuit is referred to as an output flop.
FIG. 2A is a diagram illustrating a dynamic circuit 204 in conjunction with an input flop 202 and an output flop 206. As shown in FIG. 2A, at the rising edge of the clock signal, the input flop 202 provides a set of input to the dynamic circuit 204. At the rising edge of the clock signal, the dynamic circuit 204 is in evaluation mode. When the dynamic circuit 204 is in evaluation mode, the logic of the dynamic circuit 204 is evaluated, using the input from the input flop 202, to produce a set of output. Also at the next rising edge of the clock, the output flop 206 reads and stores the output from the dynamic circuit 204.
Dynamic circuits may be arranged in a series of two or more dynamic circuits. When multiple dynamic circuits are arranged in a series, the output of one dynamic circuit is the input to the next dynamic circuit in sequence. FIG. 2B is a diagram illustrating a circuit 210 that comprises series of three dynamic circuits (named A, B, and C) in conjunction with an input flop and an output flop. As FIG. 2B illustrates, the output of the input flop is the input to dynamic circuit A, the output of dynamic circuit A is the input to dynamic circuit B, and so on.
FIG. 2B also illustrates a timing diagram 212 of the signals of circuit 210. The rising edge of the clock signal triggers each dynamic circuit of circuit 210 to enter evaluation mode contemporaneously. For example, as the timing diagram 212 shows, the rising edge of the clock causes: (1) the input flop to produce data on signal d as output, (2) dynamic circuit A to evaluate its logic using the data signal d as input to produce data on signal q1 as output, (3) dynamic circuit B to evaluate its logic using data on signal q1 as input to produce data on signal q2 as output, and (4) dynamic circuit C to evaluate its logic using data on signal q2 as input to produce data on signal q3 as output.
A problem with storing data, produced by dynamic circuit C, in the output flop may be encountered. The output flop reads the value of signal q3 at the rising edge of the clock. As the timing diagram 212 shows, because of the delays in evaluating the logic of dynamic circuits A, B, and C, when the output flop reads the value of q3, dynamic circuit C has not yet generated an output on signal q3. Also, shortly after the time that dynamic circuit C does produce an output on signal q3, the falling edge of the clock causes dynamic circuit C to enter pre-charge mode, which, in turn, causes dynamic circuit C to output a logical low value on signal q3.
As a result, when the output flop reads the value of signal q3, the value of signal q3 has been driven to a logical low by the prior falling edge of the clock. In effect, the data produced by dynamic circuit C is passing by the output flop without the output flop being able to read the data. Thus, the output flop will never be able to read the output value of dynamic circuit C, and the value of signal q produced by the output flop will always be a logical low, as shown in timing diagram 212.
To solve this problem, a one-shot clock signal may be applied to the last dynamic circuit in the series, e.g., in this case, a one-shot clock signal is applied to dynamic circuit C. A one-shot clock signal is a clock signal that extends the period of time in which the dynamic circuit receiving the one-shot clock signal stays in evaluation mode. In this way, the length of time that the output of dynamic circuit C is available to be read on signal q3 is extended. Thus, the output flop may read the output produced by dynamic circuit C on signal q3 at the next rising edge of the clock signal.
To illustrate this technique, consider FIG. 2C, which is a diagram illustrating a circuit 220, similar to that shown in FIG. 2B, except that a one-shot clock signal is applied to dynamic circuit C in FIG. 2C. FIG. 2C also shows a timing diagram 222 of the circuit 220 shown in FIG. 2C. As shown in the timing diagram 222, the length of time that the data produced by dynamic circuit C on signal q3 is available to be read by the output flop is extended since the one-shot clock signal is applied to dynamic circuit C. Thus, the output flop may read the output produced by dynamic circuit C in signal q3 at the next rising edge of the clock. In this way, signal q produced by the output flop reflects the evaluation of the series of dynamic circuits A, B, and C, instead of always being driven to a logical low value as is the case in FIG. 2B.
On occasion, it has been observed that a set of circuits containing a dynamic circuit receiving a one-shot clock signal may not behave as intended. It is desirable to ensure that circuits behave as intended. Consequently, an approach for ensuring the proper behavior of circuits is desirable.
The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.

Apparatus to shift to pre-charge mode a dynamic circuit driven by one-shot clock signal during power off mode


In the vehicle of the invention, when the driver releases a depressed accelerator pedal, the drive control sets a vehicle speed V at the moment to a target vehicle speed V* (step S440). An engine and a motor for outputting driving power are controlled to drive the vehicle at the target vehicle speed V*. When the driver steps on a released brake pedal, the drive control stores the target vehicle speed V* set before the driver's depression of the brake pedal as a previous target vehicle speed Vpre and cancels the setting of the target vehicle speed V* (steps S470 and S480). In response to the driver's subsequent release of the brake pedal, the drive control sets the vehicle speed V at the moment to the target vehicle speed V* (step S510) and restarts constant-speed drive (cruise drive). When the driver turns a steering wheel to or over a preset degree for a left turn or a right turn, the drive control sets the previous target vehicle speed V* to the target vehicle speed V* (step S520) and restarts the constant-speed drive. This arrangement ensures easy and quick start of the constant-speed drive (cruise drive) and enables the constant-speed drive (cruise drive) according to the variation of the driving state.

One proposed technique sets a target vehicle speed equal to a constant vehicle speed, which is kept for a preset time period since the driver's ON operation of a main switch for constant-speed drive control and attains the constant-speed drive of the vehicle at the set target vehicle speed (see, for example, Japanese Patent Laid-Open Gazette No. 2000-6682). This proposed vehicle cancels the constant-speed drive in response to the driver's accelerator-on operation or brake-on operation.


An apparatus for delivering a surgical device to a predetermined location within a tubular organ includes an elongated delivery member having a proximal and a distal end, a mounting mechanism for detachably mounting the surgical device at the distal end of the elongated delivery member and a releasing mechanism for releasing the surgical device from the mounting mechanism.

1. Field of the Invention
This invention relates to a surgical delivery apparatus, and in particular, to an apparatus for delivering an anvil component to a remote location within a hollow organ to effect the joining of hollow organ sections by circular anastomosis.
2. Description of the Prior Art
Circular anastomosis is the surgical joining of separate hollow organ sections so that the sections intercommunicate. Typically, the anastomosis procedure follows surgery in which a diseased or defective section of hollow tissue is removed and the remaining end sections are to be joined. In accordance with such procedures, the operative tissue is exposed by making several extensive incisions in the body cavity wall and folding the cut tissue to provide access to the surgical site. The diseased section of the organ is removed thereby leaving two separate end sections of organ which are thereafter fastened by means of a stapling instrument which drives a circular array of staples through the end sections and simultaneously cores out any overlapping tissue to free the tubular passages.
Examples of such instruments for performing anastomosis of hollow organs are described in U.S. Pat. Nos. 4,304,236, 4,379,457, 4,573,468, 4,576,167, 4,603,693 and 4,646,745 all of which are incorporated herein by reference. In instruments of the types exemplified by these patents, opposed end portions of the organs to be stapled are clamped between an anvil component and a staple holding component, both of which are located at the distal end of the instrument. The clamped tissue is stapled by driving one or more staples from the staple holding component so that the ends of the staples pass through the tissue and are clinched by the anvil component.
In the typical application of joining first and second intestinal sections together, the operative tissue is accessed by forming at least one incision across the midline of the lower abdomen and folding the cut tissue to reveal the surgical site. The intestinal section in question is isolated and removed leaving the first and second intestinal end sections to be joined by anastomosis. The stapling instrument with mounted anvil component is applied to the operative site. Each end of the intestinal sections to be attached is then secured to their respective stapler or anvil component by a well-known purse string stitch to cause the tissue portions to tighten and to remain on the apparatus in position for permanent attachment by the staples. Thereafter, the anvil component is manually brought into close proximity to the staple holding component. The instrument is fired and the intestinal sections are attached by circular rows of staples or fasteners.
In some applications of the circular anastomosis technique, it is necessary to utilize a surgical instrument in which the anvil component is detachably mounted to the staple holding component. In such cases, the stapling instrument is introduced either surgically or transanally into the first intestinal section without the anvil component in place. The anvil component is subsequently surgically inserted within the second intestinal section. Both intestinal sections are secured to their respective anvil or stapler component by a drawstring. The anvil component is thereafter mounted within the staple holding component and the instrument is fired to complete the anastomosis. However, in such procedures the surgical site must be exposed by conventional surgical methods, i.e., incising of the lower section of the abdomen in order to emplace the anvil and join the tissue. This is undesirable in that it requires additional, often excessive time, causes additional trauma to the patient, and unnecessarily delays the anastomosis procedure. Further, it precludes the surgeon from using minimally invasive techniques to complete the anastomosis.
Therefore, in attaching first and second intestinal sections by circular anastomosis, it is highly desirable to prepare the intestinal sections and perform anastomosis using minimally invasive surgical techniques, particularly in situations which require the anvil component to be applied into an intestinal section independently from the stapling instrument. The present invention achieves this objective by providing a delivery system to be inserted transanally into the patient to deliver an anvil component through the intestine and to a targeted position therewithin. Thereafter, the intestinal sections can be laparoscopically severed to resect a defective or diseased tissue portion. The anvil component may be mounted within the staple holding component by laparoscopic means and the anastomosis completed.


An apparatus, system, and method are disclosed for automatically displacing a faulty in-use member battery in an electric equipment, such as electric vehicle, powered by an array of member batteries configured to self detect battery fault conditions and output a control signal upon such detection. By use of a charged spare battery and deactivated single pole double throw relay switches with activation means for coupling all batteries, member batteries are normally interconnected in series electrically to provide a predetermined voltage, with the spare battery standing by. While the electric equipment is in operation, as soon as a member battery detects a fault, the corresponding relay switch is activated to cause the faulty member battery to be electrically bypassed by the battery array. Concurrently, the spare relay switch is activated to electrically connect the spare battery to the battery array in series, thereby displacing the faulty in-use member battery.

1. Field of the Invention
This invention relates to multiple-battery electric systems, and more particularly relates to electric equipment, such as an electric vehicle, powered by a redundant array of batteries.
2. Description of the Related Art
Electric equipment, such as an electric vehicle ("EV"), utilizes chemical energy stored in rechargeable batteries which is converted to electricity. EVs use electric motors instead of, or in addition to, internal combustion engines. In the latter case, the EV is referred to as a hybrid electric vehicle ("HEV"). At the heart of an EV, there are three main components: batteries, electric motor controller, and electric motor. Batteries supply power to the electric motor controller, which controls the amount of voltage and current supplied to the electric motor based on the position of the accelerator pedal. Batteries used in EVs vary in type, number, voltage and placement. Operating voltage can be 360 volts (or higher). With the use of 12-volt batteries, for instance, 30 batteries (or more) connected in series are required to obtain such voltage.
Nowadays more and more EVs are traveling on the U.S. roads and highways. Batteries used to power the EVs are rapidly becoming very important components of the vehicles. Current battery technology is adequate for EVs with a range, for example, of 250 miles, but the batteries are still rather expensive and require elaborate safety mechanisms. One type of batteries known as lithium-ion batteries, being widely used in laptops, cell phones, and other mobile devices, fall in that category. In the wake of recent massive recalls of Sony lithium-ion batteries used in millions of laptop computers because of incidents of battery overheating or bursting into flames, many industry experts are paying tremendous attention to the safety enhancements of these batteries, as well as other types of batteries.
Because of the small form factor, environmentally friendliness, and desired energy density achievability, lithium-ion cells, in particular, are increasing in popularity among some EV manufacturers as well, when selecting batteries for their end products. Some battery packs they use are capable of delivering as much as 200 kilowatts of electric power. For that kind of capacity, the manufacturers consider safety as a primary criterion in the battery pack's design and architecture. Packaging and cooling system designs are also important considerations.
In addition to cell-level safety protection, those manufacturers provide multiple battery pack level safety features. Besides cell fuses, a pack that may include a number of battery modules has module fuses, each guarding against a short circuit across the complete module. Microprocessors, logic circuitry and sensors are used to continually monitor voltages, currents and temperatures within the pack. During normal vehicle operation, the battery logic board communicates with the vehicle to initiate battery cooling, report state of charge, and signal battery faults. Additionally, to enhance battery safety, whenever at least one of the fault conditions, such as over current, short circuit, cell and pack over-voltage and over temperature, occurs, with a certain design, the battery cells are disconnected from the system by turning off two back-to-back protection MOSFETs that are connected in series with the battery pack. Manufacturers claim that a fundamental element of the vehicle and battery pack safety design is the ability to electrically disconnect the high voltage of the pack from the rest of the vehicle (by controlling high voltage contactors, for example) if any number of adverse conditions are detected.
If the EV is moving when a serious cell failure occurs, the numerous built-in electronic sensors will detect the failure and will disconnect the high voltage from the vehicle. Unfortunately, this will bring the vehicle to a stop, with all the high voltage and energy contained within the battery pack. Following a serious battery failure, the vehicle will be inoperable until the battery pack is serviced. This can happen anywhere on the road, causing the vehicle driver to be stranded, possibly in the middle of nowhere. That can place him/her in an unsafe situation.
From the foregoing discussion, it should be apparent that a need exists for an apparatus, system, and method that enable the EV to keep moving until the driver determines it is safe to stop the vehicle for a service action on the faulty battery. Beneficially, such an apparatus, system, and method would enhance the value of the EV.

Apparatus, system, and method for automatically displacing a faulty in-use battery in a battery-powered electric equipment


A resistive switching device includes a first material layer between a first electrode and a second electrode. The first material layer has a first region and a second region parallel to the first region. The first region corresponds to a conducting path formed in the first material layer, and is configured to switch from a low-resistance state to a high-resistance state in response to an applied voltage that is greater than or equal to a first voltage. The second region is configured to switch to a first resistance value that is less than a resistance value of the first region in the high-resistance state when the applied voltage is greater than or equal to a second voltage. The first region remains constant or substantially constant when the second region has the first resistance value.

1. Field
Example embodiments relate to resistive switching devices and/or memory devices including the same.
2. Description of the Related Art
Examples of non-volatile memory include a resistance random access memory (RRAM), a magnetic random access memory (MRAM), a ferroelectric random access memory (FRAM), and a phase-change random access memory (PRAM). RRAMs include a resistive switching device and write data by using the resistance switching characteristics of the resistive switching device.
Resistive switching devices switch to one of two different resistance states and retain the resistance state until subsequent switching occurs without electrical power. During repeated resistance switching of the resistive switching devices, a RRAM writes and deletes data.
In order to provide stable operation of a RRAM, guarantee of reproducibility and durability against repeated resistance switching is required. To achieve this, it is necessary for a resistive switching device to maintain uniform resistance for each of two resistance states.

Resistive switching devices and memory devices including the same


A method of performing bone correction on a computerized tomography (CT) image includes the steps of:                A. generating a reconstructed CT image of a bone-containing portion of a patient's body, the reconstructed CT image including a bone region corresponding to the bone-containing portion;        B. determining characteristics of the bone region of the image; and        C. performing a bone correction procedure on the image, the bone correction procedure being performed at a gain that is determined based on the bone region characteristics.

FIG. 1 is a schematic axial view of a conventional third generation CT scanner which includes an x-ray source 12 and an x-ray detector system 14 secured to diametrically opposite sides of an annular shaped disk 16. The disk 16 is rotatably mounted within a gantry support (not shown), so that during a scan the disk 16 continuously rotates about a longitudinal z-axis while x-rays pass from the source 12 through an object, such as a patient 20, positioned on a patient table 56 within the opening of the disk 16. The z-axis is normal to the plane of the page in FIG. 1 and intersects the scanning plane at the mechanical center of rotation 18 of the disk 16. The mechanical center of rotation 18 of the disk corresponds to the "isocenter" of the reconstructed image.
In one conventional system, the detector system 14 includes an array of individual detectors 22 disposed in a single row in a shape of an arc having a center of curvature at the point 24, referred to as the "focal spot," where the radiation emanates from the x-ray source 12. The source 12 and array of detectors 22 are positioned so that the x-ray paths between the source and each detector all lie in a "scanning plane" that is normal to the z-axis. Since the x-ray paths originate from what is substantially a point source and extend at different angles to the detectors, the diverging x-ray paths form a "fan beam" 26 that is incident on the detector array 14 in the form of a one-dimensional linear projection. The x-rays incident on a single detector at a measuring interval during a scan are commonly referred to as a "ray," and each detector generates an output signal indicative of the intensity of its corresponding ray. The angle of a ray in space depends on the rotation angle of the disk and the location of the detector in the detector array. Since each ray is partially attenuated by all the mass in its path, the output signal generated by each detector is representative of the attenuation of all the mass disposed between that detector and the x-ray source, i.e., the attenuation of the mass lying in the detector's corresponding ray path. The x-ray intensity measured by each detector is converted by a logarithmic function to represent a line integral of the object's density, i.e., the projection value of the object along the x-ray path.
The output signals generated by the x-ray detectors are normally processed by a signal processing portion (not shown) of the CT system. The signal processing portion generally includes a data acquisition system (DAS) which filters the output signals generated by the x-ray detectors to improve their signal-to-noise ratio (SNR). The output signals generated by the DAS during a measuring interval are commonly referred to as a "projection," "projection profile," or "view" and the angular orientation of the disk 16, source 12 and detector system 14 corresponding to a particular projection profile is referred to as the "projection angle."
If the detector array consists of N detectors, then N projection values are collected at each rotation angle. With the rays in a fan shape, these N projection values are collectively called a fan-beam projection profile of the object. The data of fan-beam projection profiles are often reordered or rebinned to become parallel-beam projection profiles. All rays in a parallel-beam profile have the same angle, called the parallel-beam projection view angle. The image of the object can be reconstructed from parallel-beam projection profiles over a view angle range of 180 degrees.
During a scan, the disk 16 rotates smoothly and continuously around the object being scanned, allowing the scanner 10 to generate a set of projections at a corresponding set of projection angles. In a conventional scan, the patient remains at the constant z-axis position during the scan. When obtaining multiple scans, the patient or the gantry is stepped along the longitudinal z-axis between scans. These processes are commonly referred to as "step-and-shoot" scanning or "constant-z-axis" (CZA) scanning. Using well-known algorithms, such as the inverse Radon transform, a tomogram may be generated from a set of projections that all share the same scanning plane normal to the z-axis. This common scanning plane is typically referred to as the "slice plane."
A tomogram is a representation of the density of a two-dimensional slice along the slice plane of the object being scanned. The process of generating a tomogram from the projections is commonly referred to as "reconstruction," since the tomogram may be thought of as being reconstructed from the projection data. The reconstruction process can include several steps including reordering to form parallel-beam data from the fan-beam data, convolution to deblur the data, and back projection in which image data for each image pixel is generated from the projection data. In CZA scanning, for a particular image slice, all the projections share a common scanning plane, so these projections may be applied directly for convolution and to the back projector for generation of a tomogram.
In some instances, for instance when the image consists of scans of the skull, the reconstructed images are further processed with a Beam Hardening Correction ("BHC") operation, which is used to estimate regional tissue composition. This information is then used to adjust the predicted beam hardening transformation which is a function of tissue composition. The BHC is based on the assumption of a uniform average tissue composition. A monotonic transformation is predicted or measured based upon the average tissue composition. However, this procedure can result in certain artifacts being present in the corrected image in the form of a bleeding of the bone into the adjacent soft tissue which destroys the bone-brain interface in the image. These artifacts degrade the quality of the image and, in some cases, can render the image useless for certain diagnostic purposes.
Typically, a second-pass BHC operation or an Iterative Bone Correction ("IBC") operation is performed on the BHC corrected image to compensate for the artifacts generated by the first-pass BHC. The effectiveness of the second pass correction depends on properties of the bone of the skull. It is more effective in images of adult skulls than in children's or infant skulls because of the increased density of the adult skull. Since the skull of an infant or child is less dense, the second-pass correction tends to overcorrect the image, resulting in a gap in the bone-brain interface in the image, which can equally render the image useless for diagnostic purposes. FIGS. 2A and 2B are reconstructed images of a CT scan of the skull of a two year old child. FIG. 2A shows a reconstructed image which has not had a second correction pass done. As can be seen, the first-pass correction resulted in a bleeding between the bone region of the image 12 and the brain region of the image 14, such that the bone-brain interface 16a is blurred and not easily discernable. FIG. 2B shows a reconstructed image which has had a second-pass correction performed. As can be seen, because the correction is performed at a gain which is used in bone correction operations of adult CT images, the lower density and area of the bone region 12 causes the image to be overcorrected, resulting in a gap in the bone-brain interface 16b between the bone region 12 and the brain region 14. In scans of infants (aged up to one year) the overcorrection is more pronounced, due to the low density and area of the bone in the skull.
In order to avoid the problems associated with the second pass correction in reconstructed scans, the second pass is not performed in younger patients. As stated above, in very young infants, the lack of the second pass correction does not adversely affect the scans because beam hardening is less likely to occur in the first pass correction operation. However, because of differences in the growth patterns of children, there is no clear age at which the second pass correction can be performed without resulting in some amount of overcorrection.

Adaptive iterative bone correction in computerized tomography


A video viewing system for a vehicle including a vehicle having a battery which, through an inverter, powers a video and audio generating source. The source transmits video signals to a projector which is also powered by the vehicle battery. The projector is affixed to the vehicle, and operative to project video images onto a screen. The screen is removably attached to the hood or a bumper of the vehicle and disposed in cooperation with the projector. The source transmits audio signals to the vehicle's sound system via an adapter or to an independent sound system. An optional multi-output jack can be connected to the audio output of the source to connect the sound systems of multiple vehicles to the source in the host vehicle.

1. Field of the Invention
This invention relates generally to a system for viewing a video while seated in a vehicle where the projector and screen are attached to the vehicle, and more particularly to the combination of a projector, screen, source and vehicle, where the projector and screen are attached to the vehicle and disposed in cooperating fashion with each other, and the source supplies video signals to the projector and audio signals to the vehicle's sound system through an adapter, where the source, projector and sound system are powered by the vehicle's battery.
2. Brief Description of the Prior Art
To date there have been many systems for projecting signals from a source, such as a VCR tape or receiver, onto a screen for viewing purposes. Most of the time a sound system is connected to the source for audio effects in addition to the video presentation.
The viewing can be accomplished in an enclosed area, customarily in a home or conference room. The source, projector and sound system are plugged in to the house power (the 110 volt outlet). Although it is possible to operate these components using a battery for power, the use of a battery is not common because most every viewing area is equipped with enough 110 volt outlets to power all of the components.
To date, the only combination of a video viewing system and a vehicle has been the drive-in movie theater. The screen, as well as the sound speakers, are fixed in their locations, making the drive-in theater non-portable. The sound quality of the sound system at most drive-in theaters is poor. Because the components are exposed, drive-ins cannot operate during rain or snow. The images projected onto the drive-in screen cannot be seen during daylight and therefore the drive-ins can only operate at nighttime.
Although many video viewing systems exist and have existed for almost a decade, none has been specifically designed for mobile or portable use. By projecting an image from within the cab of a car or truck onto a screen situated at one end of the vehicle (such as attached to the front bumper or atop the hood), a video may be viewed in one's own vehicle regardless of the location of the vehicle. The system is mobile (i.e. portable) and is powered from the vehicle's battery. An external sound system is not necessary as the audio effects can be connected through the vehicle's existing internal sound system, such as a cassette deck or CD player. This feature expands the usefulness of expensive car stereo systems. Further, the system provides privacy and reduces disturbance to neighbors, especially those sharing common walls as in apartments or condominiums.
This system can be used in conjunction with any type of vehicle having a battery, such as a car, truck, semi-truck, motorcycle or boat.


A submersible scrubbing device using a direct current electric motor powered by rechargeable batteries. The device has a longitudinal body, with the rotating brush tool positioned in line with the body, to allow the tool and the device to be inserted into narrow passageways. The housing of the device is designed to prevent water from entering the device. Variously configured scrubbing brushes or scrubbing tools are used with the device.

Hand held, battery powered devices having rotary action are known in the art. Examples of these devices are battery powered screwdrivers and drills. The hand held, battery powered, tools of the prior art are characterized by a motor which drives the tool. A rechargeable battery is commonly used to provide direct current to the motor. These devices allow tools to be removably attached, such as by means of insertion of the tool into a tool holder or chuck. These tools may include variously sized screwdriver blades, or variously sized drills.
The hand held battery powered tools of the prior art which have rotary action typically are not water submersible. Accordingly, these devices cannot be used with tools such as brushes in an environment in which a substantial amount of water is present. An example of such an environment is the process of washing dishes, which presents a hostile environment of water of an elevated temperature along with chemicals to aid in cleaning.
Rotary scrubber devices are found in the prior art. However, devices such as Enriquez, U.S. Pat. No. 5,353,461, turn the direction of rotation ninety degrees (90.degree.) from the body of the device. This arrangement prevents the device from being capable of insertion into, for example, glassware which have long, narrow internal cavities for the purpose of cleaning the inside of the glassware.

Powered water submersible scrubbing device


The present invention relates to a source-antenna for transmitting/receiving electromagnetic waves comprising an array of n radiating elements (113, 114) operating in a first frequency band, means (20) with longitudinal radiation operating in a second frequency band, the array and the means with longitudinal radiation having a substantially common phase centre, the n radiating elements being arranged symmetrically about the longitudinal-radiation means, and each element (113, 114) of the array consisting of a radiating element of the travelling wave type.

Interactive wireless telecommunication services are developing ever more rapidly. These services relate in particular to telephony, telefax, television, the Internet network and any so-called multimedia domain. The equipment for these general-broadcast services have to be available at reasonable cost. This is true in particular for the user's transmission/reception system which has to communicate with a server, usually by way of a telecommunication satellite. In this case, the communications are performed in the microwave frequency domain, especially in the C, Ku or Ka bands, that is to say at frequencies lying between 4 GHz and 30 GHz.
For the transmission (T)/reception (R) source antennas, use is usually made of waveguide devices generally comprising a wide frequency band corrugated horn so as to cover the two bands, transmission and reception, this horn being associated with a device allowing the separation of the transmission and reception paths and/or the orthogonal polarizations and which consist of an orthomode (or OrthoMode Transducer: OMT) and of waveguide filters on each of the ports.
The implementational technology is unwieldy and expensive. Its weight and bulk are generally incompatible with use by individuals.
Thus, the applicant has already proposed in Patent WO99/35711 in the name of THOMSON Multimedia a transmission/reception source-antenna situated at the focus of a focusing system, such as a spherical lens, a parabolic-reflector antenna or a multireflector antenna, which may be used in home terminals for satellite communication systems. In this case, the source-antenna used for illuminating the lens or the parabolic reflector consists of an array of N radiating elements, i.e. of N patches for one direction of link such as reception and of a longitudinal-radiation antenna such as a helix, a dielectric rod, with axis coinciding with the axis of radiation or any other type of longitudinal-radiation antenna for the other direction of link for example transmission, this antenna being situated at the centre of the array. Thus the phase centres of the longitudinal-radiation antenna and of the array of patches practically coincide and can be placed at the focus of the system of antennas.
In order for this type of mixed source to ensure maximum decoupling between the array of N radiating elements of patch type and the longitudinal-radiation antenna such as a helix, it is preferable for the array of patches to be used for the link effected at low frequency, i.e. in reception, and for the longitudinal-radiation antenna to be used for the link effected at high frequency, i.e. in transmission.
However, the reception frequency band generally being wider than the transmission frequency band and the link budget being more sensitive to losses of the reception source, the choice of an array of patches for the reception source is not optimal from this point of view.
Moreover, with an array of patches, it is often difficult to obtain circular polarization of good quality throughout the reception band. However, most communication systems using low-orbit satellites operate with circular polarizations.
The aim of the present invention is therefore to propose an optimal solution to the problems hereinabove, in the case of satellite communication systems using circular polarizations.

Source-antennas for transmitting/receiving electromagnetic waves


A method, and apparatus for accomplishing the method, of compressing data for transmission over a communications channel by receiving one or more data symbols comprising a current data string and at least one subsequent symbol, matching a longest previous data string with the current data string, the previous data string being defined by a code word, placing the code word into a compressed data stream, attempting to extend the current data string by a plurality of symbols, placing, in the event the current data string is extended, a string-extension length indicative of the plurality of symbols into the compressed data stream, and transmitting the compressed data stream though the communications channel.

The present invention relates to data compression (i.e., creation of compressed data from uncompressed data) and decompression (i.e., recovery of the uncompressed data from the compressed data).
Data compression systems are known in the prior art that compress a stream of digital data signals (uncompressed bits) into compressed digital data signals (compressed bits), which require less bandwidth (fewer bits) than the original digital data signals, and that decompress the compressed digital data signals back into the original data signals or a close approximation thereof. Lossless data compression systems decompress the compressed digital data signals back into the original data signals exactly. Thus, lossless data compression refers to any process that converts data into an alternative data form that requires less bandwidth, i.e., has fewer bits, than the data converted in a process that is reversible so that the original data can be recovered.
Accordingly, the objective of data compression systems is to effect a savings in an amount of storage required to hold the data or the amount of time (or bandwidth) required to transmit the data. By decreasing required space for data storage or required time (or bandwidth) for data transmission, data compression results in a monetary and resource savings.
A compression ratio is defined as the ratio of the length of the data in the alternative data form (compressed data) to the length of the data originally (original data). Thus defined, the smaller the compression ratio, the greater will be the savings in storage, time, or bandwidth.
If physical devices such as magnetic disks or magnetic tape are utilized to store the data, then a smaller space is required on the device for storing the compressed data than would be required for storing the original data, thereby, e.g., utilizing fewer disks or tapes for storage. If telephone lines, satellite links or other communications channels are utilized for transmitting digital information, then lower costs, i.e., shorter transmission times and/or smaller bandwidths, result when compressed data is employed instead of original data.
Data compression systems can be made particularly effective if the original data contains redundancies such as having symbols or strings of symbols appearing with high frequency. In fact, redundancies in the original data is a requirement for lossless data compression. A data compression system operating on original data containing redundancies may, for example, transform multiple instances of a symbol, or transform a string of symbols, in the original data into a more concise form, such as a special symbol or group of symbols indicating multiple occurrences of the symbol, or indicating the string of symbols, and thereafter translate or decompress the concise form back into the multiple instances of the symbol, or back into the string of symbols.
For example, it may be desirable to transmit the contents of a daily newspaper via a satellite link or other communications link to a remote location for printing. Appropriate sensors within a data compression system may convert the contents of the newspaper into a data stream of serially occurring characters for transmission via the satellite link. If the millions of bits comprising the contents of the daily newspaper were compressed before transmission and decompressed at the receiver, a significant amount, e.g., such as 50% or more, of transmission time (or bandwidth) could be saved. As a further example, when an extensive database such as an airline reservation database or a banking system database is stored for archival or backup purposes, a significant amount of storage space, such as 50% or more, can be saved if the database files are compressed prior to storage and decompressed when they are retrieved from storage.
To be of practical and general utility, a digital data compression system should satisfy certain criteria. Specifically, one criterion is that the system should provide high performance, i.e., compression/decompression rates, for both compression and decompression with respect to the data rates in the communications channel being utilized, be it a data bus, a wired network, a wireless network or the like. In other words, data transmission rates seen by a sender of uncompressed data and a receiver of the uncompressed data should not be reduced as a result of compression/ decompression overhead. In fact, effective data rates may be significantly increased over slow communications channels, because more original data can be transmitted per unit time, if the original data is compressed preceding and following transmission, since there is less compressed data to transmit than there would have been original data.
The rate at which data can be compressed (i.e., the compression rate) is the rate at which the original data can be converted into compressed data and is typically specified in millions of bytes per second (megabytes/sec). The rate at which data can be decompressed (i.e., the decompression rate) is the rate at which compressed data can be converted back into original data. High compression rates and high decompression rates are necessary to maintain, i.e., not degrade, data rates achieved in present day disk, tape and communication systems, which typically exceed one megabyte/sec. Thus, practical data compression systems must typically have compression and decompression rates matching or exceeding some application-dependent threshold, e.g., one megabyte/sec.
The performance of prior art data compression systems is typically limited by the speed of the random access memories (RAM) and the like utilized to store statistical data and guide the compression and decompression processes. High performance compression rates and decompression rates for a data compression system can thus be characterized by a number of cycles (read and write operations) required per input character into or out of the data compression system. Fewer memory cycles per input character leads to higher performance compression rates and decompression rates.
Another important criterion in the design of a data compression and decompression system is compression effectiveness. Compression effectiveness is characterized by the compression ratio of the system, i.e. a smaller compression ratio indicates greater compression effectiveness. However, in order for data to be compressible using a lossless data compression system, the data to be compressed must contain redundancies. As a result, the compression ratio, or compression effectiveness, in a lossless data compression system (and to a lesser degree in a lossy data compression system) is a function of the degree of redundancy in the data being compressed. The compression effectiveness of any data compression system is also affected by how effectively the data compression system exploits, for data compression purposes, the particular forms of redundancy in the original data.
In typical computer stored data, e.g., arrays of integers, text, programs or the like, redundancy occurs both in the repetitive use of individual symbology, e.g., digits, bytes or characters, and in frequent recurrence of symbol sequences, such as common words, blank record fields, and the like. An effective data compression system should respond to both types of redundancy.
A further criterion important in the design of data compression and decompression systems is that of adaptability. Many prior art data compression procedures require prior knowledge, or the statistics, of the data being compressed. Some prior art procedures adapt to the statistics of the data as it is received, i.e., adaptive data compression systems, and others do not, i.e., non-adaptive data compressions systems. Where prior art procedures do not adapt to the statistics of the data as it is received, compression effectiveness is reduced, but where such procedures do adapt to the statistics, an inordinate degree of complexity is required in the data compression system. An adaptive data compression system may be utilized over a wide range of information types, which is typically the requirement in general purpose computer facilities, while a non-adaptive data compression system operates optimally only on data types for which the non-adaptive data compression system is optimized. Thus, it is desirable that the data compression system achieves small compression ratios without prior knowledge of the data statistics, i.e., that the data compression system is adaptive. Many data compression systems currently available are generally not adaptable and so cannot be utilized to achieve small compression ratios over a wide range of data types.
General purpose data compression procedures are known in the prior art that either are or may be rendered adaptive, two relevant procedures being the Huffman method and the Tunstall method. The Huffman method is widely known and used, reference thereto being had in an article by D. A. Huffman entitled xe2x80x9cA Method for the Construction of Minimum Redundancy Codesxe2x80x9d, Proceedings IRE, 40:10, pp.1098-1100 (September 1952). Further reference to the Huffman procedure may be had in an article by R. Gallagher entitled xe2x80x9cVariations on a Theme by Huffmanxe2x80x9d, IEEE Information Theory Transactions, IT-24:6, (November 1978). Adaptive Huffman coding maps fixed length sequences of symbols into variable length binary words. Adaptive Huffman coding suffers from the limitation that it is not efficacious when redundancy exists in input symbol sequences which are longer than the fixed sequence length the procedure can interpret. In practical implementations of the Huffman procedure, the input sequence lengths rarely exceed 12 bits due to RAM costs and, therefore, the procedure generally does not achieve small compression ratios. Additionally, the adaptive Huffman procedure is complex and often requires an inordinately large number of memory cycles for each input symbol. Thus, the adaptive Huffman procedure tends to be undesirably cumbersome costly and slow thereby rendering the process unsuitable for most practical present day installations.
Reference to the Tunstall procedure may be had in the doctoral thesis of B. T. Tunstall entitled xe2x80x9cSynthesis of Noiseless Compression Codesxe2x80x9d, Georgia Institute of Technology, (September 1967). The Tunstall procedure maps variable length input system sequences into fixed length binary output words. Although no adaptive version of the Tunstall procedure is described in the prior art, an adaptive version could be derived which, however, would be complex and unsuitable for high performance implementations. Neither the Huffman nor the Tunstall procedure has the ability to encode increasingly longer combinations of source symbols.
A further adaptive data compression system that overcomes some of the disadvantages of the prior art is that disclosed in U.S. Pat. No. 4,464,650 for APPARATUS AND METHOD FOR COMPRESSING DATA AND RESTORING THE COMPRESSED DATA, issued Aug. 7, 1984 to Cohen. The procedure of Cohen parses the stream of input data symbols into adaptively growing sequences of symbols. The procedure, however, suffers from the disadvantages of requiring numerous RAM cycles per input character and utilizing time consuming and complex mathematical procedures such as multiplication and division to effect compression and decompression. These disadvantages tend to render the Cohen procedure unsuitable for numerous economical high performance implementations.
An even further adaptive data compression system that overcomes some of the disadvantages of the prior art is that disclosed in U.S. Pat. No. 4,558,302 for HIGH SPEED DATA COMPRESSION AND DECOMPRESSION APPARATUS AND METHOD, issued Dec. 10, 1985, to Welch. The procedure of Welch compresses an input stream of data symbols by storing, in a string table, strings of symbols encountered in an input stream. The Welch procedure next searches the input stream to determine the longest match to a stored string of symbols. Each stored string of symbols includes a prefix string and an extension character that is a last character in the string of symbols. The prefix string includes all but the extension character.
When a longest match between the input data stream and the stored strings of symbols is determined, the code signal for the longest match is transmitted as the compressed code signal for the encountered string of symbols and an extension character is stored in the string table. The prefix string of the extension character is the longest match, i.e., the longest stored string of symbols located in the search. The extension character of the extended string is the next input data character signal following the longest match.
Searching through the string table and entering extension characters into the string table is effected by a limited searching hashing procedure. Unfortunately, even the improved data compression system of Welch suffers from less than optimal compression effectiveness, and less than optimal performance. As a result, the Welch procedure, like the Cohen procedure, is unsuitable for many high performance implementations.
The present invention advantageously improves upon the above-described approaches by providing a lossless data compression (i.e., creation of compressed data from uncompressed data) and decompression (i.e., recovery of the uncompressed data from the compressed data) approach that improves on heretofore known data compression and decompression approaches.
In one embodiment, the present invention can be characterized as a method of data compression for transmission over a communications channel. The method comprises the steps of receiving one or more data symbols comprising a current data string; matching a longest previous data string with the current data string; placing, in the event the longest previous data string having been matched is a single symbol, the single symbol into a compressed data stream; placing, in the event the longest previous data string having been matched is a multiple symbol data string, a code word into the compressed data stream, wherein the code word is indicative of the longest previous data string; attempting, in the event a multiple symbol data string is matched, to extend the string by one or more symbols by comparing the symbols following the matched previous data string with the symbols following the current data string whose said code word was placed; placing, in the event the multiple symbol data string can be extended, a string-extension length indicative of the number of symbols that matched; placing a one or two bit code prefix into the compressed data stream, the one or two bit code prefix indicating whether the following bits are said single symbol, said code word, or said string-extension length; and transmitting the compressed data stream through the communications channel.
In accordance with a further aspect of the present invention, a method for decompressing data received over a communications channel is provided. The method comprises the steps of receiving a plurality of bits; determining whether the plurality of represents a single symbol, code word, or string-extension length; placing, in the event the plurality of bits represents a single symbol, the single symbol into an output data stream; placing, in the event the plurality of bits represents a code word, a data string defined by the code word into the output data stream; and placing, in the event the plurality of bits represents a string-extension length, an extension string being copied from said output data stream at a symbol following a last symbol of the previous code word processed. The receiving step comprises receiving a code prefix consisting of one or two bits and a plurality of subsequent bits. The determining step comprises determining, using said code prefix, whether said plurality of subsequent bits represents said single symbol, said code word, or said string-extension length.

Data compression for use with a communications channel