A system for dynamically adapting a communication channel to channel impairments includes a spectrum monitor configured to determine a channel impairment characteristic related to a channel impairment present in the channel. The system includes a system manager configured to determine a quality metric indicative of channel performance for the channel, and adjust one or more operating parameters in a set of channel operating parameters when the quality metric is not within a target range, whereby the communication channel operates in accordance with the adjusted parameters.

1. Field of the Invention
The present invention relates generally to telecommunications systems and, more particularly, to shared access RF networks.
2. Background
In conventional shared access communication networks, such as a hybrid fiber coaxial (HFC) network, a bidirectional communication path is maintained between a network headend and each remote point in the network. The communication path simultaneously carries broadband radio frequency (RF) signals in two directions on the same medium by dividing the frequency spectrum of the bidirectional communication path. Frequency division multiplexing (FDM) allows two or more simultaneous and continuous channels to be derived from a shared access transmission medium. FDM assigns separate portions of the available frequency spectrum to the "downstream" or "forward path" direction from a headend signal source to a plurality of remote points, and a second frequency range for carrying signals in the "upstream" or "return path" direction from each remote point to the headend.
For example, a conventional cable modem system provides a point-to-multipoint topology for supporting data communication between a cable modem termination system (CMTS) at a cable headend and multiple cable modems (CM) at the customer premises. In such systems, information is broadcast on downstream channels from the CMTS to the cable modems as a continuous transmitted signal in accordance with a time division multiplexing (TDM) technique. In contrast, information is transmitted upstream from each of the cable modems to the CMTS on the upstream channels as short burst signals in accordance with a time division multiple access (TDMA) technique. The upstream transmission of data from the cable modems is managed by the CMTS, which allots to each cable modem specific slots of time within which to transfer data.
Conventional cable modem systems utilize DOCSIS-compliant equipment and protocols to carry out the transfer of data packets between multiple cable modems and a CMTS. The term DOCSIS (Data Over Cable System Interface Specification) generally refers to a group of specifications published by CableLabs that define industry standards for cable headend and cable modem equipment. In part, DOCSIS sets forth requirements and objectives for various aspects of cable modem systems including operations support systems, management, data interfaces, as well as network layer, data link layer, and physical layer transport for data over cable systems. The most current version of the DOCSIS specification is DOCSIS 2.0. In DOCSIS 2.0, advanced physical layer technology is added for which some of the benefits include more robust operation in impaired RF upstream channels.
One technical challenge in operating a network having a bidirectional communication path on a shared medium between the headend and each remote point is maintaining network integrity for signals transmitted in the forward path and return path directions. Noise and other undesirable energy originating at one remote point or at any point along the return path from that remote point can impair network communications for all remote points in the network. Similarly, where noise and undesirable energy from one remote point is combined with noise and or other RF impairments from other remote points in the network, network communications are impaired.
RF impairments occur in many forms or types including, but not limited to, impulse and/or burst noise, common path distortion, and ingress such as interference from radio communication and navigation signals. Impulse noise or burst noise consists of high-power, short-duration energy pulses. The high-power energy pulse results in a significant increase in the noise floor while the short duration results in an elusive disruption whose source or entry point into the network is difficult to pinpoint.
Ingress is unwanted energy that enters a communication path from a source external to the communication path. Ingress often comprises radio and/or navigational communication signals propagated over the air that enter a weak point in a wireline network, although it may also comprise impulse and/or burst noise that is similarly propagated over the air to enter the network at a weak point. Weak points in the network often occur where there is a shield discontinuity, improperly grounded electrical device, or a faulty connector at or near a remote point. When radio frequency carriers from shortwave radio, citizen's band radio, or other broadcast sources enter the network at these weak points, they cause interference peaks at specific carrier frequencies in the communication path.
Common path distortion is the result of second and higher order mixing products from the downstream channel that couple to the upstream channel and occur when physical electromechanical connectors corrode and oxidize creating point contact diodes. The effect of these diodes in the return path is additional interference that is generally narrowband at fixed frequencies spaced at regular 6 MHz intervals in the frequency spectrum.
Conventional techniques for mitigating the above-mentioned and other impairments tend to be stationary in time. That is, the techniques assume the presence of relatively static impairments. However, the impairments mentioned above tend to be highly dynamic. That is, the impairments tend to change both in type and level or extent over time. Thus, static impairment mitigation techniques tend to be ineffective against the dynamic impairments. Therefore, there is a need to mitigate dynamic impairments in a communication system.

Dynamic adaptation of impaired RF communication channels in a communication system


A byte aligner and frame synchronizer for 622 Mbit/s high speed data includes a clock divider, a data width extension circuit, a byte alignment controller, a byte alignment circuit, a pattern selector, a continuous pattern detector, a frame pulse generator, a frame sync detector, a frame sync loss detector, and frame sync error detector, and performs byte alignment very fast while also stabilizing frame synchronization by reinforcing an error correction function.

1. Field of the Invention
The present invention relates to the field of communications, and more particularly, to a byte aligner and frame synchronizer for data transmission of 622 Mbit/s used in high-speed data communication systems.
2. Description of Related Art
Today, high speed data communication requires a byte aligner and frame synchronizer which can accomodate high speed data such as data of 622 Mbit/s rate or higher.
The conventional frame synchronizers are commonly used for data of 155 Mbit/s rate or lower. But, applied to high speed data communication, such a frame synchronizer needs a long synchronization time, more hardware and high-priced manufacture because of its structural problems. Explaining in more detail, since it has to perform frame synchronization using all of the frame bytes, the conventional frame synchronizer has to wait for all of the frame bytes and this needs a considerably long time to effect frame synchronization. In addition, since it processes data serially, for accommodating 622 Mbit/s data, such a frame synchronizer needs more hardware and high-priced manufacture.
Therefore, seen in view of performance and economy, the conventional frame synchronizer is not appropriate for application to 622 Mbit/s data.
In general, in high speed data communication such as time-division multiplex of synchronous transport module-4 concatenation (STM-4C), data is transmitted by a frame unit with a period of 125 .mu.sec which data is not only allocated sequentially to the corresponding time slots but twenty-four frame bytes are also inserted in the data stream every 125 .mu.sec. Then, at the receiver, frame synchronization is acquired by extracting the frame signal from received data according to a pre-defined rule.
According to the ITU-T standard, the frame format for STM-4C is as follows: twelve A1 bytes stream whose binary bits are 11110110 and continuously twelve A2 bytes stream whose binary bits are 00101000. In addition, such frame bytes are defined to place in the front position of STM-4C data stream.
Fujimoto's U.S. Pat. No. 4,748,623 disclosed only frame synchronization and serial-to-parallel conversion without byte alignment. According to this disclosure, this device confirms whether the frame sync pattern is present or not in the received data, and then once present, it extracts a frame pulse from the received data and makes a timing control signal for a frame pulse. Such a timing control signal adjusts the liming of received data to acquire a frame synchronization correctly.
However, since it requires such complex processes and is invented for 155 Mbit/s, for applying to the frame synchronization for 622 Mbit/s data, this disclosure has disadvantages that it increases the clock frequency and the amount of hardware. In addition, it needs more precise byte alignment hardware to prevent byte alignment error during serial-parallel conversion.
Another conventional art, which is disclosed in U.S. Pat. No. 4,748,623, acquires frame synchronization using a parallel processing method. After this disclosure detects the frame synchronization pattern, it compares its timing using a timing comparator and synchronization protection circuit and then adjusts the timing of the frame synchronization by a timing controller.
But, because of not having the frame error control function, detecting the analogous pattern with the frame pattern, this disclosure operates automatically unnecessary processes such as frame synchronization and timing adjustment. Thus, because it is liable to malfunction by an analogous frame pattern, this disclosure is not appropriate for 622 Mbit/s data in which can occur more analogous frame patterns than in lower speed data.
For still another reference, there is a paper by DooWhan Choi entitled "Frame alignment in a digital carrier system" (hereinafter referred to as paper 1) in IEEE comm. magazine (Feb. 1990). Paper 1 deals with frame alignment in the digital carrier system with an added-bit frame and burst frame, and suggests simulation results of acquisition time and loss time in frame synchronization. However, paper 1 presents only ideal conditions and ideal values for improving the performance of frame synchronization, but has no specific implementation for frame synchronization.
For a further reference, there is a paper (hereinafter referred to as paper 2) by Lin Xiaokang entitled "A new design of the STM-1 frame aligner" in ECC'93. Paper 2 shows the method of frame synchronization in the STM-1 frame structure. That is, this paper describes the method of frame synchronization acquired by searching the A1A1A2 pattern among eight frame bytes using parallel processing. But, since this paper describes technologies for 155 Mbit/s data only, it is not appropriate to apply this technique to frame synchronization for 622 Mbit/s data.

Byte aligner and frame synchronizer for 622 MBIT/S high-speed data

Electronics and Telecommunications Research Institute


There is provided an oxidizing gas sensor that includes an insulating substrate, a gas sensing layer laminated on the insulating substrate and substantially made of tin oxide so as to make resistance changes in response to concentration variations in oxidizing gas and a plurality of catalyst grains applied to a surface of the gas sensing layer and substantially made of gold, wherein 20% or more of the catalyst grains have an aspect ratio of 2.0 or greater when viewed at from the surface of the gas sensing layer.

The present invention relates to an oxidizing gas sensor having a gas sensing layer formed of a metal oxide semiconductor material on an insulating substrate so as to make resistance changes in concentration variations in oxidizing gas. The present invention also relates to an oxidizing gas production method.
There are known various metal oxide semiconductor gas sensors, each of which includes a sensor element that features a gas sensing layer formed of a metal oxide semiconductor material on an insulating substrate to detect concentration variations in oxidizing gas such as nitrogen oxide (NOx) in response to resistance changes in the gas sensing layer due to the transfer of electrons in a surface portion of the gas sensing layer.
In one type of metal oxide semiconductor gas sensor, the sensor element has a catalyst portion in contact with the gas sensing layer, as disclosed in International Publication WO 2004/048957A1, for improvement in gas detection performance.

Oxidizing gas sensor and production method thereof


A feeder handle (16) for a hot glue dispenser (10) has a main body portion (30) which defines a hand grip (35), and a forward end portion (32) which extends forward of the main body portion (30) for releasibly engaging a cartridge barrel (20) having a heating cartridge (22) for heating a stick of glue (15) and dispensing a melted end of the stick of glue (15) therefrom. The forward end portion (32) of the feeder handle (16) includes a protruding portion (34) which slidably engages within a mounting channel (28) formed into the cartridge barrel (20) to align the main body portion (30) of the feeder handle (16) and the cartridge barrel (20) when the cartridge barrel (20) is mounted to the feeder handle (16). A feeder mechanism (18) is mounted to the feeder handle (16), and includes a feed member (90) which is selectably moveable to advance the stick of glue (15) toward a dispensing end of the cartridge barrel (20). An electric switch (32) is mounted to the feeder handle (16) and is actuated by an actuation member (40), which is mounted to the cartridge barrel (20), such that electric power is automatically disconnected from a first power connector (36) of the feeder handle (16) when the cartridge barrel (20) is removed from the feeder handle (16).

Hot glue dispensers have been utilized for dispensing hot glues for use as an adhesive. The hot glue dispensers, which are often called glue guns, have been made as a single units which have a heater section which is permanently mounted to a dispenser section. The dispenser sections of the hot glue dispensers have included a glue feeder assembly and a pistol grip handle. If a person using such a glue dispenser wished to dispense two different types of glue from a single dispenser, such as glues having different colors, thicknesses or other properties, the first type of glue stick had to be removed from within the hot glue dispenser and any remaining glue discharged from within the glue dispenser prior to inserting and dispensing the second type of glue.
Hot glue dispensers typically include resistive heating elements which are heated to elevated temperatures for melting glue sticks. These elevated temperatures pose hazards to persons if the heating elements are not enclosed within a thermally protective housing. Additionally, electrical current is necessary for the heating elements to operate. Persons utilizing hot glue dispensers may also suffer injury if they touch hot electrical contacts for providing electrical power to the resistive heating elements.


A compound useful for reducing fouling in a hydrocarbon refining process is provided. A method for preparing the compound includes hydrohalogenating a polymer having a vinyl chain end to obtain a halogen-containing terminal group, and reacting the terminal group with a polyamine. Methods of using the compound and compositions thereof are also provided.

Petroleum refineries incur additional energy costs, perhaps billions per year, due to fouling and the resulting attendant inefficiencies caused by the fouling. More particularly, thermal processing of crude oils, blends and fractions in heat transfer equipment, such as heat exchangers, is hampered by the deposition of insoluble asphaltenes and other contaminants (i.e., particulates, salts, etc.) that may be found in crude oils. Further, the asphaltenes and other organics are known to thermally degrade to coke when exposed to high heater tube surface temperatures.
Fouling in heat exchangers receiving petroleum-type process streams can result from a number of mechanisms including chemical reactions, corrosion, deposit of existing insoluble impurities in the stream, and deposit of materials rendered insoluble by the temperature difference (ΔT) between the process stream and the heat exchanger wall. For example, naturally-occurring asphaltenes can precipitate from the crude oil process stream, thermally degrade to form a coke and adhere to the hot surfaces. Further, the high ΔT found in heat transfer operations result in high surface or skin temperatures when the process stream is introduced to the heater tube surfaces, which contributes to the precipitation of insoluble particulates. Another common cause of fouling is attributable to the presence of salts, particulates and impurities (e.g., inorganic contaminants) found in the crude oil stream. For example, iron oxide/sulfide, calcium carbonate, silica, sodium chloride and calcium chloride have all been found to attach directly to the surface of a fouled heater rod and throughout the coke deposit. These solids promote and/or enable additional fouling of crude oils.
The buildup of insoluble deposits in heat transfer equipment creates an unwanted insulating effect and reduces the heat transfer efficiency. Fouling also reduces the cross-sectional area of process equipment, which decreases flow rates and desired pressure differentials to provide less than optimal operation. To overcome these disadvantages, heat transfer equipment are ordinarily taken offline and cleaned mechanically or chemically cleaned, resulting in lost production time.
There is a need to reduce precipitation/adherence of particulates and asphaltenes from the heated surface to prevent fouling, particularly before the asphaltenes are thermally degraded or coked. Such reduction will improve the performance of the heat transfer equipment, decrease or eliminate scheduled outages for fouling mitigation efforts, and reduce energy costs associated with the processing activity.
Antifoulant additives have been described in a number of commonly-owned applications, including U.S. Patent Application Publication Nos. 20110147275 and 20100170829, the disclosure of each of which is incorporated herein by reference in its entirety. However, there remains a need for alternative antifoulant additives capable of reducing precipitation and/or adherence of particulates and asphaltenes.

Hydrohalogenation of vinyl terminated polymers and their functionalized derivatives for fouling mitigation in hydrocarbon refining processes

ExxonMobil Research and Engineering Company


The invention relates to a steering wheel armature cover (10) for mounting to a steering wheel armature (12) of a vehicle steering wheel (14), comprising a cover portion (16) for closing a profile of the steering wheel armature (12) open in cross-section as well as at least one securing element (18, 20, 22) for fixing the steering wheel armature cover (10) to the steering wheel armature (12). Furthermore, the invention also relates to a method of manufacturing a steering wheel armature cover (10) as well as to a vehicle steering wheel (14) comprising such steering wheel armature cover (10).

The invention relates to a steering wheel armature cover, a method of manufacture thereof and a vehicle steering wheel comprising such steering wheel armature cover.
From prior art, numerous vehicle steering wheels comprising a hub and a steering wheel rim have been known already, the steering wheel rim being connected to the hub by at least one spoke. As a load-bearing core such steering wheels usually comprise a metal armature to which at least in portions a foam-coating is applied. This foam-coating then either forms a visible steering wheel surface or is used as a carrier for an optional heating mat as well as for lining elements, e.g. made from wood or leather.

Steering wheel skeleton cover, method for producing same, and steering wheel having such a steering wheel skeleton cover


A soft resin pellet is provided comprising at least one liquid (B) having a kinematic viscosity at 25° C. ranging from 0.5 to 100,000 cSt (centistokes) and a surface tension at 25° C. ranging from 10 to 50 dyn/cm, and at least one fine powder (C) of an average particle diameter of not more than 50 μm, which fine powder adheres to the surface of pellets of at least one soft resin having a tensile modulus determined according to ASTM D-658 not higher than 1600 Mpa.

Soft resins such as olefin copolymer rubber like ethylene/propylene copolymer rubber, and ethylene/propylene/diene copolymer rubber are marketed usually in a shape of blocks such as bales.
Such a block-shaped olefin copolymer rubber have disadvantages of troublesomeness in taking-out from a storage site, and in supply or transportation to a molding and processing apparatus, and in weighing.
Accordingly, the olefin copolymer rubber, if supplied in a pellet form, can be free from the above disadvantages, and has various advantages: an extruder of high productivity can be used for preparing a compounded rubber from the pelletized olefin copolymer rubber and a compounding ingredient in place of the less efficient mixer like a Banbury mixer conventionally used for blending an olefin copolymer rubber and a conventional formulating ingredient such as fillers, softeners, and vulcanizing agents.
However, the above olefin copolymer rubber, even if it is pelletized, will cohere together into blocks during storage owing to the stickiness of the olefin copolymer resin itself to lose the advantages of the pelletization.
Even an ethylene/α-olefin copolymer elastomer which is less sticking at an ordinary temperature can cause cohesion of the pellets when the pellets are stored with a load applied thereon or stored in a high temperature environment in summer, thereby decreasing the value as a pelletized product.
Various methods have been disclosed for decreasing the surface stickiness of the pellets of the inherently sticky olefin copolymer rubber, or preventing cohesion of the pellets of an olefin elastomer, which is less sticky in ordinary temperature, under a load and/or at a high temperature. For example, the surface of the rubber pellets is coated with a silicone oil (Japanese Patent Application Laid-Open No. 48(1973)-47934). In another method, a powdery matter such as powdery inorganic substances like talc, silica, and calcium carbonate, or a powdery polyethylene is dusted onto the pellets as an anti-blocking agent to allow the powdery matter to adhere to the sticky pellet surface.
However, the coating of the surface of the rubber pellets or elastomer pellets with a silicone oil has a disadvantage that the intended sufficient effects cannot be achieved for the pellets having a strong stickiness. With the latter method, the powdery matter dusted can give adverse effects in the properties of the rubber in end use, since the inorganic material like talc and silica is not compatible with the olefin copolymer rubber. Furthermore, in this method of dusting of a powdery matter, the stickiness-preventing powdery matter is used in an amount from several to ten-and-several percents based on the weight of the pellets to prevent substantially the cohesion of the pellets. Such a large amount of the powdery matter will impair the properties of the treated olefin copolymer rubber. For example, the rubber properties of a vulcanized olefin copolymer rubber dusted with powdery polyethylene become deteriorated with increase of the amount of the adhering powdery polyethylene. Further, with this method, dustiness of the pellet surface impairs the external appearance of the pellets and makes the handling troublesome.
An effective countermeasure against the pellet cohesion is disclosed by the inventors of the present invention (Japanese Patent Application Laid-Open No. 56(1981)-136347) in which rubber pellets are coated with a higher fatty acid and/or a salt thereof. This method can prevent the sticking of rubber pellets without impairing the rubber properties substantially.
However, the inventors of the present invention found that the method disclosed in the above Patent Laid-Open Publication cannot allow the higher fatty acid and/or its salt to adhere stably in a sufficient amount onto rubber pellets since the higher fatty acid and/or its salt is simply mixed with the rubber, and may still cause blocking (cohesion) during storage, or after transportation, weighing, and other treatment.
The inventors of the present invention, after comprehensive investigation, disclosed a method of preventing the blocking of the rubber pellets during storage, in which the olefin copolymer rubber pellets, fine powdery higher fatty acid of 12–30 carbon atoms and/or its salt, are mixed in the presence of a monohydric alcohol of 1–4 carbon atoms to prepare less sticky rubber pellets (Japanese Patent Publication No. 4(1992)-1011). The rubber pellets coated with the higher fatty acid and/or its salt produced according to this method do not cause blocking, even after the pelletized rubber is transported, packed into bags in an amount of 25 kg per bag, and bags are stacked up in 10 stairs for one month. In this method, however, the powder-dusted state of the pellet surface may cause some trouble in handling.
At the moment, to meet the users' request, appearance of a pelletized soft resin which is nonsticky and has excellent appearance, and is easily handleable in comparison with conventional pelletized soft resins like olefin copolymer rubbers, and a method of producing the same is desired.
The present invention intends to solve the above problems of the prior art techniques, and to provide a soft resin pellet which is nonsticky and has excellent appearance, and is easily handleable in comparison with conventional pelletized soft resins like olefin copolymer rubbers, and a process for production thereof.

Flexible resin pellet and process for producing the same


A composite acoustic wave device provides improved protection from environmental factors while maintaining high electrical characteristics and dynamic range is provided. The device comprises a rigid protector plate having high quality acoustical characteristics and a thickness which is a multiple of half wavelength of the resonant frequency. A piezoelectric plate is coupled to the protector plate, is supported therefrom, and forms an energy interface therewith. The piezoelectric and protector plates are dimensioned such that a wave of resonant frequency traveling between the excitation face and the loaded/sensing face, forms a substantially continuous-phase wave, at substantially peak amplitude, at the energy interface. By doing so the device decouples the electrical thickness of the wave device from the mechanical thickness thereof.

Piezoelectric sensors are well known. They are used for sensing material properties such as viscosity and density, for detecting the presence of certain materials in an environment, for measuring purity of fluid substance, and the like. Structures known for acoustic sensing range from the simple crystal resonator, crystal filters, acoustic plate mode devices, Lamb wave devices, and the like. Briefly, these devices comprise a substrate of piezoelectric material such as quartz, langasite or lithium niobate, or thin films of piezoelectric material, such as aluminum nitride, zinc oxide, or cadmium sulfide, on a non-piezoelectric substrate. The substrate has at least one active piezoelectric surface area, which in most cases is highly polished. Formed on the surface are input and output transducers for the purpose of converting input electrical energy to acoustic energy within the substrate and reconverting the acoustic energy to an electric output signal. These transducers may consist of parallel plate and co-planar plate (bulk-generated acoustic wave) or periodic interdigitated (surface-generated acoustic wave) transducers. It is noted that a single transducer may act both as the input and the output transducer.
Piezoelectric materials interconvert electrical and mechanical signals and energy, allowing an electrical circuit to be responsive to a physical effect on the mechanical properties of a vibrating system. The literature presents countless instances of detecting temperature, pressure, added mass, viscoelastic variations, magnetic fields and the like using these sensors. The interactions between the devices and the electronic circuits have historically included the response of the device's phase or amplitude at a given frequency and changes in the resonant frequency or damping of a natural resonant mode of the device. Both phase delay and resonant frequency can be employed to create an oscillator circuit, ultimately providing frequency change as the circuit response to ambient physical influences.
Piezoelectric sensors can be designed to operate while being fully immersed in fluid. However the sensitive electronics are then subjected to, in the least, noise signals and reading errors and, in the extreme, to corrosion or even explosive hazards. Passivation of the electronics surface is well known and is suitable in some limited applications, as seen for the Love Wave and surface transverse wave (STW) sensors. However passivation is not complete and electrical components of the circuit are still exposed to capacitive loading and noise injection. Moreover, most passivation methods require the use of material having poor acoustic characteristics compared to single crystal materials. Finally, these passivated surface wave based sensors exhibit undesirably high shear rate for many liquid phase measurements. While such sensors potentially address many sensor applications, they are not ideal, for instance, in measuring fluids in oil production, especially in down-well environments.
More preferably the frequency of measurement is maintained below approximately 10 MHz and the preferred geometries employ the thickness of the piezoelectric plate to form a waveguide.
In most applications only the surface opposite the transducers is in direct or indirect contact with the fluid being measured and interfaces acoustic energy to and from it. In addition to the interface function, the piezoelectric material forms a protective membrane between the fluid and a cavity containing electrical components of the sensor.
As the cavity behind the piezoelectric plate material is commonly not pressurized to the same level of the fluid, the piezoelectric plate acts as a membrane between the high and low pressure environments, and is exposed to the pressure difference between the fluid and the pressure within the cavity. Therefore, the finite strength of the material limits the operating pressure to which the sensor may be exposed. Even if the material is sufficiently strong to withstand the pressure, the nonlinear effect on the sensor of membrane flexure will severely affect the sensor characteristics.
As increasing material thickness increases the membrane strength, a simple solution will be to increase the thickness of the piezoelectric membrane. This however suffers from reduced acoustic coupling, reduced efficiency and dynamic range, and other disadvantages, whether the piezoelectric material is operated at fundamental or at overtone operating mode.
Yet another disadvantage of the present piezoelectric sensors is lack of resistance to harsh chemicals, abrasion, and the like. Thus for example, an excellent piezoelectric material such as langasite will deteriorate in certain acidic environments and other piezoelectric materials such as lithium tetraborate are water soluble.
In PCT application No. PCT/US06/15510 to Andle, I disclosed a composite acoustic wave device (AWD) which is adapted for operation at high ambient pressures. The AWD comprises two piezoelectric plates in a symmetric back to back relationship, with electrodes disposed between the plates. The plates are bonded so as to neutralize the effects of external pressure, which is isobaric under immersion. This application is incorporated herein by reference in its entirety.
Several devices are reported in the literature, such as "Measurement of the equivalent circuit parameters of chemical interface layers on bulk acoustic wave resonator" by G J Gouws, R. C. Holt, and J Zhen, Proceedings of the 2004 IEEE International Frequency Control Symposium and exposition, "PMMA polymer film characterization using thickness-shear mode (TSM) quartz resonator" by Boima Morray, Suiqiong Ii, Jeanne Hossenlopp, Richard Cernosek, and Fabien Josse, 2002 IEEE International Frequency Control Symposium and exposition, and others. Those devices add a layer of polymer, or metal deposited by thin or thick film technologies to the exposed sensing surface. In some cases such layers may be a quarter or even half wavelength thick. In such devices, the lateral extent of the added layer is limited by the piezoelectric plate size, and does not support the piezoelectric, but is rather supported therefrom. Thus film deposition methods do not provide additional resistance to pressure or encapsulation from environmental damage.
A high overtone bulk acoustic resonator, also known as HBAR, is a compressional wave device, comprising a piezoelectric layer grown on the end of a sapphire or garnet rod of a large number (at least over 100) of half wavelengths in length. An intentional acoustic mismatch between the sapphire and the piezoelectric plate allows the device to have a very high reflection of the energy trapped therein, and thus generate a number of extremely sharp transfer peaks. The sharp transfer peaks allow the HBAR to act as an extremely high Q filter. However, the weak acoustic coupling and the compressional wave operation mode make the device ill suited for liquid-phase sensor duty, which requires a shear wave. Furthermore to obtain a highly responsive electrical response to a mechanical effect requires as tight coupling as possible to work efficiently. Furthermore, as will be seen infra, unlike the HBAR, the present invention attempts to minimize wave reflection at the energy interface, while the HBAR attempts to maximize such reflection in order to generate the high Q, multiple mode operation. The present invention is generally directed to a narrow band, frequency selective, and resonant finite impulse device, while the HBAR is directed to a compressional wave, multiple frequency device.
Many technology areas may benefit from measuring fluid with low sensitivity to pressure variations or at high pressure levels, as well as providing for harsh chemical or abrasive materials. Examples of such technologies include by way of a non-limiting example, gas production, oil well and oil pipes, hydraulic systems, in-service lubricant monitoring, injection molding equipment, anti terror detection system for detection of biological and chemical substances, and the like. Therefore there is a long felt and heretofore unanswered need in the industry for an electro acoustic sensor, which in various embodiments is capable of operating with low sensitivity to pressure variations, in high ambient pressure environments, and/or in harsh chemical or abrasive environments. The present invention aims to provide a solution to any single one of the above conditions, or to any combination thereof.

Asymmetric composite acoustic wave sensor


A snap together spring block enables the reliable capture, formation and support of metallic conductors known as lead frames. First and second body halves are designed to mate forming the complete spring block. Each body half incorporates a plurality of cavities and projections, similar to hills and valleys. The cavities and projections can be designed to fit various configurations of lead frames. Integrally molded or formed into one of the body halves is an internal attachment mechanism, such as a clip, which is designed to fit an internal recess molded into the second body half, or mating half, of the spring block for mating the two halves. The plurality of cavities and projections are alternately spaced such that when the first body half is mated to the second body half, the projections are received within the cavities forming a plurality of apertures. Because each half contains both cavities and projections, a plurality of planes are formed when the mating halves are joined, in which lead frames are interposed. The conductors are supported such that they remain rigidly fixed relative to each other. Formed into external surface of second body half is a radius and parallel channels adapted to receive the metallic conductors of the lead frames when the metallic conductors are formed downwardly and rearwardly around the radius of the external surface of the second body half.

In telephony wiring, the need frequently arises for the capture and support of metallic conductors within a dielectric supporting device known as a "spring block." The metallic conductors are typically part of an assembly known as a lead frame. Prior art spring blocks use a variety of techniques to bond the dielectric material in order to support the lead frame in the proper relationship. For example, ultrasonic bonding is a technique used to join components of prior art spring blocks and is disclosed in U.S. Pat. No. 3,699,498, which issued on Oct. 17, 1972 to Hardesty et al. and U.S. Pat. No. 5,096,442, which issued on Mar. 17, 1992 to Arnett et al. This technique, as described in the foregoing documents, requires the application of an ultrasonic wave to a spring block, which deforms the material of the spring block, thus joining the components.
Prior art spring blocks also use a technique in which a metallic conductor is inserted through an orifice in the spring block and then formed to the desired shape. This technique is disclosed in U.S. Pat. No. 3,850,497, which issued on Nov. 26, 1974 to Krumreich et al.
The prior art techniques fail to provide a reliable, compact, and simple mode of support and isolation of the metallic conductors of the lead frame. While other prior art spring blocks disclose a snap together mode of attachment, they fail to provide a variable conductor mounting surface that can accommodate various shapes and patterns of lead frames. For example, see U.S. Pat. No. 4,820,192, which issued on Apr. 11, 1989 to Denkmann et al.


In a method of processing a call in response to a connection request that includes reported bandwidths in both upstream and downstream directions, a communication node on the calling side (1) manages available bandwidths in upstream and downstream directions on a per-path basis; (2) searches for a path having upstream/downstream available bandwidths, which are greater than the upstream/downstream reported bandwidths; (3) if such a path can be found, accepts the call connection request as a call communicated in both directions on this path; (4) if such a path cannot be found, searches independently for a path having an available bandwidth greater than the upstream reported bandwidth and a path having an available bandwidth greater than the downstream reported bandwidth; and (5) if these two paths can be found, accepts the call connection request as a call communicated on the separate paths on a per-upstream- and downstream-direction basis.

This invention relates to a method of call processing at a communication node. More particularly, the invention relates to a method of call processing at a communication node in which, when the bandwidth of a path (line) between communication nodes undergoes upstream and downstream management separately and a call connection request that includes upstream/downstream reported bandwidths is issued, makes it possible to accept the call upon making the path for upstream communication and that for downstream communication different from each other.
In multimedia communications, there are many cases where communication speeds in the upstream and downstream directions differ, or in other words, where the necessary bandwidths in the upstream and downstream directions differ. In such cases, the conventional practice is to reserve the same bandwidth for the upstream and downstream directions on one path, as in the manner of telephone communications. That is, by reserving the bandwidth for whichever of the upstream or downstream direction requires the larger bandwidth, the bandwidths in both the upstream and downstream directions are assured. With this method, however, bandwidth that is not actually used also is reserved as necessary bandwidth. As a consequence, there is a decline in the efficiency with which the trunk circuit connecting communication nodes is used. Economy is sacrificed as a result.
Accordingly, a technique has been proposed (see the specification of Japanese Patent Application Laid-Open No. 61-56542) in which a connection request only in the upstream direction or a connection request only in the downstream direction is handled independently, thereby eliminating waste of upstream/downstream line bandwidth so that bandwidth will be utilized effectively. However, such prior art cannot deal with a call connection request that includes reported bandwidths in both the upstream and downstream directions. As a consequence, this technique cannot be applied to call admission control in which a call connection request includes reported bandwidths in both the upstream and downstream directions, as is the case in an ATM (Asynchronous Transfer Mode) network.
Accordingly, consideration has been given to a method that includes (1) managing the bandwidth of each path (line) separately in upstream and downstream directions; (2) when a call connection request that includes upstream/downstream reported bandwidths is issued, obtaining paths (lines) that satisfy respective ones of the reported bandwidths; (3) reserving bandwidth for each direction in each reported bandwidth; and (4) performing upstream and downstream communication via the paths obtained.
FIG. 32 is a schematic view showing the configuration of a communication system for implementing such method. Numeral 1 denotes an ATM exchange on the calling side, 2 an ATM exchange on the called side, 3 and 4 terminals, and 5 and 6 trunk circuits (paths) connecting the ATM exchanges. The ATM exchange 1 includes a call controller 1a for performing call control; a path-selection information storage unit 1b for storing upstream available bandwidth, downstream available bandwidth and line status of each path; an outgoing-path management unit 1c for referring to the path-selection information to determine whether a path satisfies upstream/downstream reported bandwidths; and a failure management unit 1d for detecting line (path) failure and notifying the call controller. The ATM exchange 2 also has a structure identical with that of the ATM exchange 1 and only a call controller 2a is illustrated.
The call controller 1a decides the outgoing path by a path selection protocol PNNI in response to a dynamic call connection request of an SVC (Switched Virtual Connection) or SPVC (Soft Permanent Virtual Connection), etc. The call controller 1a then queries the outgoing-path management unit 1c as to whether the upstream/downstream available bandwidths of the decided outgoing path are equal to or greater than the respective upstream/downstream reported bandwidths in the call connection request. The outgoing-path management unit 1c refers to the call selection information, determines whether the upstream/downstream available bandwidths of the outgoing path are equal to or greater than the respective upstream/downstream reported bandwidths in the call connection request and notifies the call controller 1a of the result. If the upstream/downstream available bandwidths of the outgoing path are both equal to or greater than the upstream/downstream reported bandwidths, the call controller 1a accepts the call connection request and transmits a call-connection request message (setup message) to the ATM exchange on the called side. Further, the outgoing-path management unit 1c updates the upstream/downstream available bandwidths of the above-mentioned path in the path-selection information storage unit 1b. On the other hand, if either of the available bandwidths is less than the reported bandwidth, the call controller 1a refuses call admission and does not transmit the call-connection request message to the ATM exchange on the called side. In other words, the call-connection request message is not transmitted unless the bandwidths in both directions are satisfied on the same line, even if there is available bandwidth that satisfies either the upstream bandwidth or downstream bandwidth of the connection (SVC or SPVC).
FIG. 33 is a diagram useful in describing the call admission operation. In a case where the upstream/downstream maximum bandwidth is 156 Mbps (written simply as 156M below), (1) indicates that 100M/100M are used in communication between terminals 31, 41 as the upstream/downstream bandwidths of a path 5 and that the upstream/downstream available bandwidths are 56M/56M, and (2) indicates that 110M/50M are used in communication between terminals 33, 43 as the upstream/downstream bandwidths of a path 6 and that the upstream/downstream available bandwidths are 46M/106M. If a call connection request in which the upstream/downstream reported bandwidths are 50M/80M, respectively, is issued between terminals 32 and 42 under these conditions, the upstream available bandwidth of 56M in case of path 5 will be greater than the upstream reported bandwidth of 50M but the downstream available bandwidth of 56M will be less than the downstream reported bandwidth of 80M. Further, the downstream available bandwidth of 106M in case of path 6 will be greater than the downstream reported bandwidth of 80M but the upstream available bandwidth of 46M will be less than the upstream reported bandwidth of 50M. As a consequence, the call connection request of upstream/downstream reported bandwidths 50M/80M is refused.
An arrangement in which the upstream/downstream reported bandwidths are allocated to separate paths on a per-single-direction basis when a call connection request is issued does not exist in the prior art. Consequently, there will be many cases where a path that satisfies both the upstream/downstream bandwidths does not exist. The end result is that it is necessary to add on physical lines per se. Further, in the cases mentioned above, much wasted available bandwidth that cannot be utilized in a trunk circuit is produced.

Method of call processing at communication node


An edge seal for a chip with integrated circuits. A first metal line extends along a periphery of the chip, with a first inter-metal dielectric layer on the first metal line. A second metal line overlies the first inter-metal dielectric layer and extends along the periphery of the chip. A plurality of first metal plugs in the first inter-metal dielectric layer connects the first metal line and the second metal line and at least one first metal wall in the first inter-metal dielectric layer is laterally adjacent to a periphery of the first metal line.

The present invention relates to integrated circuits, more particularly, to edge seals for chips.
Edge seals for chips are generally used as mechanical and electrical barriers to contamination introduced in the chip sawing process.
FIG. 1 shows a semiconductor wafer 300 with a plurality of semiconductor chips 200 arranged in an array. Each semiconductor chip 200 contains circuitry to perform a specific function and has an edge seal 100 disposed along the edge thereof to prevent contamination by moisture and metal particles. Scribe lines 302 are arranged between semiconductor chips 200 where a saw can pass when separating the semiconductor chip.
FIG. 2 is a top view of semiconductor chip 200 comprising the edge seal 100 and FIG. 3 is a cross sectional view taken along line A–A′ of showing a dielectric layer IL on a semiconductor wafer 1 with a plurality of tungsten plugs 2 and metal lines 3, 5, 7, 9 of copper in the dielectric layer IL. Metal lines 3, 5, 7, and 9 are approximately parallel. A plurality of metal walls 4 are disposed between metal lines 3 and 5 comprising a plurality of trenches filled with a copper layer.
A plurality of metal walls 6 are disposed between the metal lines 5 and 7 with a plurality of metal walls 8 between metal lines 7 and 9. Metal walls 4, 6 on adjacent metal lines are staggered in the dielectric layer IL. Metal walls 6, 8 on the adjacent metal lines are also staggered and disposed in the dielectric layer IL.
Distance d1 between the metal wall 4 and the edges of metal lines 3 or 5 is large enough that delimitation P may occur at the dielectric layer IL at the edges of the metal lines 3 or 5 by thermal stress during packaging or test process.

Integrated circuit devices, edge seals therefor

Taiwan Semiconductor Manufacturing Co., Ltd.


A printed article of the present invention is a printed article comprising: a substrate; (1) a toner image which is made of a thermoplastic resin containing wax component in an amount of 3 to 15 wt %, has a surface gloss level of 5–40, and is formed on the substrate by oilless fusing or (2) a toner image which is made of a thermoplastic resin containing wax component in an amount from 3 to 15 wt % and is formed on the substrate by oilless fusing to have a surface gloss level of 25–45 and have a flat surface with a lot of concavities; and a transparent film which is laminated to the surface of the substrate, on which the toner image is formed, via an adhesive layer. The toner image not projected is easy to see (read) because of no shin. The projected image of the toner image is also excellent both in visibility and transparency. That is, the printed article is useful as a printed article for OHP. The printed article is also useful as a high gloss printed article because the toner image has a gloss level corresponding to the gloss level of a non-transparent sheet so as to exhibit good color saturation.

The present invention relates to a printed article which is useful as a printed article for OHP or a high gloss printed article, of which a toner image is formed by electrophotography, and to a production method of the same.
In a conventional image forming apparatus, a photoreceptor as a latent image carrier such as a photosensitive drum or a photosensitive belt is rotatably supported to the main body of the image forming apparatus. During the image forming operation, a latent image is formed onto a photosensitive layer of the photoreceptor and, after that, is developed with toner particles to form a visible image. Then, the visible image is transferred to a receiving medium. For transferring the visible image, there is a known method of directly transferring the visible image to the receiving medium by using a corona transfer or a transfer roller and another known method of first transferring the visible image to an intermediate transfer member such as a transfer drum or a transfer belt and then transferring it to the receiving medium.
Such methods are employed in monochrome image forming apparatuses. In addition, for a full-color image forming apparatus having a plurality of photoreceptors and developing devices, there is a known method transferring a plurality of color images on a transfer belt or a transfer drum to a receiving medium such as a paper in such a manner that the respective color images are sequentially superposed on each other, and then fixing these images. The apparatuses according to such a method using a belt are categorized as a tandem type, while the apparatuses according to such a method using a drum are categorized as a transfer drum type. Moreover, an intermediate transferring type is also known in which respective unicolor images are sequentially primary-transferred to an intermediate transfer member and the primary-transferred images are secondary-transferred to a receiving medium such as a paper at once.
Recently, transparent substrates are used as receiving media and light transmitting images are formed on such transparent substrates for projecting images on a screen using an overhead projector (OHP). Attempts have been made to form light transmitting images on transparent substrates by the electrophotography to produce such a printed article for OHP. In practice, however, there is a problem that a projected image of such a printed article for OHP is not clear because of low transparency of a toner image of the printed article and another problem that desired colors is not exactly reproduced in the image projected on the screen such that the tone of projected image is darkened compared to the tone of the toner image on the printed article for OHP. This is because the irregularity of outer surface of a toner image makes scattering or irregular reflection of lights to reduce the transmission of lights on the images so that sufficient quantity of light hardly reaches the projecting screen. This is one of the factors reducing the visibility and the transparency of the projected image. The reduction in visibility and transparency is a phenomenon exhibited particularly on a printed article for OHP using two or more colors.
Japanese Patent Publication No. H05-62342 is directed to solve the aforementioned problems and discloses that the surface roughness of a toner image is smoothed by coating the surface of the toner image with a transparent lacquer, attaching a transparent adhesive tape on the surface of the toner image, or applying heat or pressure to change the shapes of toner particles. From the description in this publication that heat or pressure is applied to the toner image for smoothing the roughness of the surface, it is found that the toner particles must be flexible and have high fluidity during fixing process. In order to prevent "filming phenomenon" of such toner particles onto a fixing roller, the fixing roller is lubricated with oil to have a resistance against toner offset at high temperature. As the fixing roller is lubricated with oil, however, the adhesive property of the transparent adhesive tape is affected so as to produce floating of a toner image in the long run, resulting in reduction in visibility and transparency of the projected image. With a toner image which is flexible and has high fluidity, a fixing roller used must have a soft outer layer for smoothing the surface of the toner image. Such fixing roller can envelope entirely the toner image when touching and thus can evenly apply thermal energy to the toner image. However, the soft fixing roller has poor durability and poor heat conductivity, so the soft fixing roller is unsuited for mass high-speed printing. In addition, when the surfaces of flexible toner particles are smoothed by applying heat or pressure, "shine" is produced on toner image. The shine makes reading of characters difficult.
On the other hand, with oilless fusing toner which can eliminate the necessity of using oil for coating the fixing roller, the filming phenomenon of toner particles to the fixing roller is prevented and resistance against toner offset at high temperature is obtained. However, the amount of wax in the toner particles is large so that the transparency is affected by solidifying property of wax, thus affecting projected images.
Besides the printed articles for OHP, attempts have been made to form an image on a non-transparent sheet with gloss as a receiving medium by employing the electrophotography to produce a high gloss printed article. Also in this case, the irregularity of outer surface of a toner image makes scattering or irregular reflection of lights to reduce the reflection of lights on the images, thus increasing difference in gloss level between the gloss level of the image and the non-transparent sheet. Such increased difference in gloss level is defects of high gloss printed articles.
In case of using oilless fusing toner, a process is taken for reducing the fluidity during fixing. The process may comprise increasing the amount of wax in toner particles or adding cross-linking component to a resin as a thermoplastic resin. The surface of the toner image after fixed includes a solidified lump of wax and has increased irregularity because the toner image is hard, thus increasing difference in gloss level between the image and the non-transparent sheet. That is, there is the same problem in case of using oilless fusing toner. The increased difference in gloss level is a phenomenon exhibited particularly on a high gloss printed article using two or more colors and only permits the production of printed articles having poor color saturation.
The first object of the present invention is to provide a printed article suitable for OHP of which a toner image is easily read and a projected image has excellent visibility and transparency and to provide a production method of the same.
The second object of the present invention is to provide a printed article suitable as a high gloss printed article of which a toner image has a gloss level nearly equal to that on a non-transparent sheet and having improved color saturation and to provide a production method of the same.

Printed article and production method of the same


A first transmission line for transmitting a first signal and a second transmission line for transmitting a second signal, which has the reverse phase of the first signal, are connected in series with a common mode choke coil. A third transmission line and fourth transmission line are each connected in series with the common mode choke coil, and transmit the first and second signals. A semiconductor device is connected in series with the third and fourth transmission lines, so as to transmit and receive the first and second signals. One end of a first terminator is connected in parallel with the first transmission line, and the other end is connected to the common mode choke coil. One end of a second terminator is connected in parallel with the second transmission line, and the other end is connected to the common mode choke coil. The noise eliminating capability of the common mode choke coil is increased by means of this structure.

1. Field of the Invention
The present invention relates to a differential transmission circuit and a common mode choke coil.
2. Background Information
In recent years there have been increasing demands for the transmission of high-frequency signals in conjunction with the diversification of electronic devices. In general, differential transmission is used for high-frequency signal transmission.
In particular, when differential transmission is applied to the transmission of high-frequency signals, electromagnetic interference affecting external electronic devices can be reduced. Moreover, differential transmission can reduce the effects of electromagnetic interference from external electronic devices.
Consider a case in which there is strong electromagnetic interference from external electronic devices, which affects differential transmission and causes noise to be carried in two transmission signals. When the noise carried in two signals is at such a high level that it exceeds the input range of the differential receiver, there is concern that the differential receiver will be subject to malfunction due to the noise in the two signals. Generally, a common mode choke coil is connected to the input terminal of the differential receiver of the differential transmission circuit in order to eliminate the noise in the signals. A common mode choke coil has the function of eliminating noise. Consequently, noise penetration in the differential receiver is prevented.
The noise suppression capability of the common mode choke coil, that is, the common mode impedance, has frequency characteristics. Therefore, the common mode choke coil cannot have a common mode impedance that is highly uniform in all frequency bands. Since the noise suppression capability is low in the frequency ranges in which the common mode choke coil has low common mode impedance, it is difficult for the common mode choke coil to effectively eliminate noise from the signals when the signals carry noise due to the influence of electromagnetic interference from external electronic devices.
Common mode chokes generate a magnetic field proportional to the common mode current of the noise flowing to the common mode choke coil. When there is substantial noise in the common mode current, the common mode choke coil is susceptible to magnetic flux saturation. As a result, there is a reduction in the noise suppression capability of the common mode choke coil.
To resolve these problems, Japanese Laid-Open Patent Publication No. 2002-261842 discloses a method for reducing the amount of noise flowing to the common mode choke coil using terminators. FIG. 23 is a diagram of the differential transmission circuit described in Japanese Laid-Open Patent Publication No. 2002-261842.
According to this construction, noise in a first signal and a second signal is divided and allocated to first and second terminators 710 and 711, and a common mode choke coil 705. Accordingly, even when the first and second signals are in the low frequency band where the common mode choke coil 705 noise suppression capability is low, noise can be eliminated by reducing the amount of noise flowing in the common mode choke coil 705. Furthermore, the phenomenon of magnetic flux saturation in the common mode choke coil 705 can also be reduced by reducing the amount of common mode current noise flowing to the common mode choke coil 705. Accordingly, the amount of noise reaching the differential receiver 709 is also inevitably reduced even though it cannot be eliminated by the common mode choke coil 705.
Furthermore, in order to avoid a decrease in the noise suppression capability of the common mode choke coil, Japanese Laid-Open Patent Publication No. 2003-046655 discloses a method which uses terminators to reduce the amount of noise flowing to the common mode choke coil, and connects external devices and the transmission lines by means of shielded serial cables. FIG. 24 is a diagram of the differential transmission circuit of Japanese Laid-Open Patent Publication No. 2003-046655.
In this construction, the noise carried by the shield 762 and the noise flowing to the first and second terminators 760 and 761 flow to the common mode choke coil 755. Therefore, the common mode choke coil 755 generates a counter electromotive force relative to the noise from the shield 762 and first and second terminators 760 and 761, and not only relative to the remaining noise flowing to the common mode choke coil 755. Accordingly, the common mode choke coil 755 has a higher noise suppression capability than the method in Japanese Laid-Open Patent Publication No. 2002-261842. Consequently, the amount of noise reaching the differential receiver 759 is reduced even though it cannot be eliminated by the common mode choke coil 755.
However, differential transmissions by these methods present the following problems.
In Japanese Laid-Open Patent Publication No. 2002-261842, when the noise in the first and second signals is so great it cannot be eliminated using the first and second terminators 710 and 711 and the common mode choke coil 705, the noise cannot be eliminated before reaching the tolerance limit of the differential receiver 709. There is therefore concern that the noise may cause malfunction of the differential receiver 709, which may in turn damage the semiconductor device. This phenomenon must be taken into account particularly when using differential transmissions for signal transmission between devices installed in automobiles. FIG. 25 shows an example in which differential transmission is used between devices installed in a vehicle. In addition to an engine, brakes and the like, onboard devices A and B are installed in the automobile shown in FIG. 25. The onboard devices A and B are a car navigation device and audio device or the like. The onboard devices A and B are provided with differential transmission transceivers C and D, respectively. The onboard device A and onboard device B transmit and receive signals using the differential transmission transceivers C and D. The engine produces strong electromagnetic interference. Therefore, the signals transmitted between the onboard devices A and B are affected even when using differential transmission. As a result, there is a high probability that malfunction will occur due to the input noise which cannot be eliminated by the differential receiver within the differential transmission circuit. Furthermore, when differential transmission does not eliminate noise from the transmission signal, the electromagnetic field can cause interference for external devices, and there is a possibility that the braking device and the like may be affected and malfunction. Accordingly, this method is difficult to apply in environments with extremely high levels of electromagnetic interference from external devices as in the case of automobiles.
In Japanese Laid-Open Patent Publication No. 2003-046655, there is increased weight and cost because the transmission line 752 is covered by the shield 762. Particularly when the differential transmission circuit of Japanese Laid-Open Patent Publication No. 2003-046655 is installed in an automobile, the weight of the shielding is 50 to 100 kg. Accordingly, the weight and cost of the shield cannot be ignored.
The present invention solves these problems by providing a differential transmission circuit and common mode choke coil used in same, which improves protection for the differential receiver and eliminates noise by a differential transmission circuit structure that is also light-weight and inexpensive.

Differential transmission circuit and common mode choke coil

Matsushita Electric Industrial Co., Ltd.


Time-continuous sigma/delta analog-to-digital converter for converting an analog input signal into a digital output signal (D), having at least one analog filter (3) which filters the analog input signal present at a signal input (2) of the analog filter (3), a quantizer (12) which is clocked by a clock signal (CLK) and quantizes the filtered analog signal, output by the analog filter (3), in order to generate the digital output signal (D), and having at least one reference capacitor (28) which can be continuously charged to a reference voltage (VREF) by a current source (31) for displacing a constant charge (Q) to/from the analog filter (3), such that no voltage jumps occur at the analog filter (3).

FIG. 1 shows a time-continuous sigma/delta analog-to-digital converter according to the prior art. The conventional sigma/delta analog-to-digital converter firstly converts an analog input signal in a sigma/delta pulse density modulator into a high-frequency serial bit sequence normally having single bit resolution, that is to say into a high-frequency coarsely quantized sample value. The modulator output signal is converted into highly resolving parallel words, which have a substantially lower sampling rate, by subsequent digital low pass filtering. The energy of the quantization noise is distributed uniformly over a wide frequency band by the oversampling.
A sigma/delta analog-to-digital converter (ΣΔADC) comprises two main constituents, specifically a delta/sigma modulator and a digital filter. Firstly, an analog-to-digital conversion of low resolution, for example single bit resolution, is executed, and the quantization noise is subsequently greatly reduced by digital filtering.
The sigma/delta modulator according to the prior art as illustrated in FIG. 1 has a feedback loop which comprises a subtractor, an integrator, a coarse quantizer or comparator and a digital-to-analog converter in the feedback branch. The quantizer comprises an analog-to-digital converter (ADC) of low resolution but with a high sampling rate, which supplies a digital output signal. The digital-to-analog converter (DAC) provided in the feedback branch generates from the digital output signal sequence a quantized analog signal or approximation signal that is subtracted at the subtractor from the analog input signal. In an implementation that is simple in terms of circuitry, the digitization or quantization is performed merely with single bit resolution, the quantizer being implemented by a simple Schmitt trigger or analog comparator. The approximation signal is compared with the analog input signal in the feedback loop, and the difference is fed in an integrated fashion to the quantizer. The control loop corrects the arithmetic mean value of the approximation voltage to the mean value of the input voltage.
FIG. 2 shows a sigma/delta modulator according to the prior art that is of simple design in terms of circuitry. The integrator is implemented in this case by an operational amplifier whose output is fed back via a capacitor to the inverting signal input of the operational amplifier. The output of the integration amplifier specifies the integrated signal at the input of a threshold comparator which supplies a digital output signal of single bit resolution. The digital output signal is fed back via an inverter and via a resistor R to a summing node which is connected to the inverting input of the operational amplifier.
The main difficulty in implementing sigma/delta analog-to-digital converters is generating the analog feedback signal fed back to the integrator. The analog feedback signal output by the digital-to-analog converter DAC should map the digital output signal as exactly as possible. In the case of a conventional sigma/delta modulator according to the prior art, as illustrated in FIGS. 1 and 2, a logically high data bit of the digital output signal (HIGH) is applied as a first reference voltage (for example VREF1=1 volt) to the inverting signal input of the operational amplifier, and a logically low signal (low) of the digital signal is fed back as a second reference voltage (for example VREF2=0 volt) to the inverting signal input of the operational amplifier.
FIG. 3 shows two approximation signals fed back to the signal input of the integrator I and which correspond to different bit sequences of the output signal. The first data bit sequence "0 1 0 1" and the second data bit sequence "0 1 1 0" are fed back in the case of the feedback signals illustrated in FIG. 3 as NRZ (Non Return to Zero) data signals to the integrator I. As may be seen from comparing FIGS. 3a and 3b, the voltage integral of the two feedback signals, which corresponds to the charge Q fed to the integrator I or drawn from the integrator I, differs for the two different data bit sequences, although they ideally have to be equal in order to ensure complete linearity of the analog-to-digital converter ADC. In order to raise the linearity, the approximation signal is therefore fed back as RZ (Return to Zero) signal, as illustrated in FIGS. 4a, 4b. As may be seen from FIGS. 4a, 4b, the voltage integral, which corresponds to the charge Q displaced to/from the integrator I, is the same for both data bit sequences, and so the linearity of the analog-to-digital converter is greatly improved by comparison with the fed back approximation signals illustrated in FIGS. 3a, 3b.
The disadvantage in the case of the approximation signals illustrated in FIGS. 4a, 4b is, however, that they are particularly sensitive to clock jitter of the clock signal (CLK). The reason for this is that in the case of the RZ approximation signals in accordance with FIG. 4, the signal pulse length is reduced by comparison with the NRZ approximation signals which are illustrated in FIGS. 3a, 3b, and so a clock jitter of the signal edges has a stronger effect on the displaced charge Q or the voltage integral. In order to reduce the sensitivity of time-continuous sigma/delta analog-to-digital converters with respect to clock jitter, use is therefore made of more strongly switched capacitors in the feedback branch of the sigma/delta modulator, as illustrated in FIG. 5. A switch S is driven by the clock signal CLK, and alternately switches a reference capacitor CREF to a reference voltage (ground) and to the inverting signal input of the operational amplifier. The comparator output is connected via a control logic to an inverter INV, and via a reference resistance RREF to the reference capacitor CREF. The reference capacitor CREF is precharged with the corresponding digital output signal in a first clock phase, and transfers a charge packet Q=C·ΔU to the integrator in a second clock phase when the switch S switches the reference capacitor CREF to the inverting input of the operational amplifier. Charge packets of constant charge Q are displaced in the second clock phase, the direction of the charge displacement depending on whether the inverter receives a falling or rising signal edge from the control logic. The recharging of the capacitor CREF is performed with an exponentially falling signal edge whose time constant is τ=RREF×CREF. Because of the falling signal pulse shape, the charge Q displaced by a clock cycle T varies only slightly when clock jitter occurs, and so the linearity of the time-continuous sigma/delta analog-to-digital converter in accordance with FIG. 5 is less sensitive to clock jitter when it occurs than are the analog-to-digital converters illustrated in FIGS. 1 and 2.
FIG. 6 shows a further sigma/delta modulator according to the prior art, which uses a switched capacitor in the feedback branch. Two switches S1, S2 are driven by a switch control logic as a function of the digital output signal of a comparator.
In a first logic state (D=1) of the digital output signal D, the two switches S1, S2 are switched in phase, that is to say the two switches S1, S2 switch the reference capacitor CREF at the same instant to ground (GND) and, in the next clock phase, on the one hand to the inverting signal input of the operational amplifier and to a reference voltage source, which supplies a reference voltage VREF. In the first clock phase when both switches S1, S2 are in the left-hand switch position, the reference capacitor CREF is discharged. In the second clock phase, a charge Q=CREF×Δu=CREF×(Vref−VGND) is displaced to the integrator I.
If the comparator outputs an output data bit D with a low logic value (D=0), the two switches S1, S2 are operated in antiparallel or phase opposition, in a first clock phase the switch S1 connecting the reference capacitor CREF to ground (GND), and the switch S2 connecting the reference capacitor CREF to the voltage source such that the reference capacitor CREF is recharged. Subsequently, in a second clock phase the switch S1 connects the reference capacitor CREF to the integrator I, and the switch S2 connects the reference capacitor CREF to ground (GND), and so the recharged capacitor CREF is discharged via the switch S2, and draws a charge Q=C×Δu from the input of the integrator I. If the logic output data bit D of the comparator is logically high (D=1), a charge packet Q is output to the integrator I in a clock cycle T from in-phase switching of the switches S1, S2. If, vice versa, the data bit D is logically low (D=0), a charge packet Q is drawn from the integrator I in a clock cycle T because of the operation of the switches S1, S2 in phase opposition.
The sigma/delta modulator according to the prior art which are illustrated in FIGS. 5, 6 certainly greatly diminish the sensitivity to clock jitter, but they have the substantial disadvantage that sizeable voltage jumps Δu occur at the signal input of the integrator 5. Consequently, the sigma/delta modulators according to the prior art which are illustrated in FIGS. 5, 6 require operational amplifiers which operate particularly quickly. Such operational amplifiers require a very high supply current, however.


An interactive projector includes a projection section, a plurality of cameras, and a position detection section for detecting a three-dimensional position of the pointing element based on images captured by the plurality of cameras. Defining a unit vector representing a normal direction of the projected screen as a projected-screen normal vector, a unit vector representing a direction of an optical axis of the first camera as a first optical axis vector, and a unit vector representing a direction of an optical axis of the second camera as a second optical axis vector, the first camera and the second camera are arranged such that an absolute value of an inner product of the second optical axis vector and the projected-screen normal vector is smaller than an absolute value of an inner product of the first optical axis vector and the projected-screen normal vector.

1. Technical Field
The present invention relates to an interactive projector capable of receiving an instruction on a projected screen by a pointing element of a user, and a system thereof.
2. Related Art
Patent Document 1 (JP-A-2012-150636) discloses a projection display apparatus (projector) capable of projecting a projected screen on a screen, and capturing an image containing an object such as a finger using a camera and detecting a position of the object using the captured image. The object such as a finger is used as a pointing element for giving an instruction on a projected screen. That is, the projector recognizes that a predetermined instruction of drawing or the like is input to the projected screen when the tip of the object is in contact with the screen, and redraws the projected screen according to the instruction. Therefore, a user can input various instructions using the projected screen as a user interface. As described above, the projector of the type capable of using the projected screen on the screen as an enterable user interface is called "interactive projector". Further, the object used for giving an instruction on the projected screen is called "pointing element".
In a typical interactive projector, whether or not an instruction is given by a pointing element is determined according to whether or not the tip of the pointing element is in contact with a screen. Therefore, detection of a distance between the tip of the pointing element and the screen is important. However, in related art, the detection accuracy of the distance between the tip of the pointing element and the screen is not necessarily sufficient and improvement of the detection accuracy is desired.

Interactive projector and interactive projection system


A lighting device having a reduced size. The lighting device has a support member (9) installed on an installation section (4c) of a backlight chassis (4), a power source substrate (6) placed behind the backlight chassis (4), and an insulation sheet (7) bonded to a bottom section (4a) of the backlight chassis (4). The installation section (4c) does not project rearward from the bottom section (4a) but projects forward. The support member (9) is installed so as not to project rearward from the bonding surface between the bottom section (4a) and the insulation sheet (7).

Lighting devices using a fluorescent tube as a light source have conventionally been known, and such lighting devices are used as backlight units for display devices such as liquid crystal display devices (see, for example, Patent Document 1).
FIG. 13 is a diagram schematically showing an example of the structure of a conventional liquid crystal display device. A description will be given below of the structure of a conventional liquid crystal display device with reference to FIG. 13.
In the conventional liquid crystal display device, as shown in FIG. 13, a backlight unit 120 is placed at the rear surface side of a liquid crystal display panel 110. And the conventional liquid crystal display device is structured such that images are displayed on the display surface (the front surface) of the liquid crystal display panel 110 by irradiating the rear surface of the liquid crystal display panel 110 with light emitted from the backlight unit 120.
The backlight unit 120 is at least provided with a metal backlight chassis 101, fluorescent tubes 102 housed in the backlight chassis 101, a reflection sheet 103 reflecting light from the fluorescent tubes 102, and an optical sheet 104 that, for example, diffuses light from the fluorescent tubes 102. The reflection sheet 103 is disposed along the housing-area-side surface of the backlight chassis 101, and the optical sheet 104 is disposed so as to cover the housing area of the backlight chassis 101 from the front side. The optical sheet 104 is also supported by a support member 105 installed on a bottom section 101a of the backlight chassis 101.
The support member 105 includes a support prop 105a for supporting the optical sheet 104 and an engagement piece 105b that engages with the bottom section 101a of the backlight chassis 101. And, the support member 105 is installed on the bottom section 101a of the backlight chassis 101 by engaging the engagement piece 105b of the support member 105 with the bottom section 101a of the backlight chassis 101. Incidentally, in the state in which the support section 105 is installed on the bottom section 101a of the backlight chassis 101, the engagement piece 105b of the support member 105 projects rearward from the bottom section 101a of the backlight chassis 101.
In the backlight unit 120 as described above, a power supply substrate 106 is typically placed behind the backlight chassis 101 for supplying power to the fluorescent tubes 102. In this case, for electrically insulating the backlight chassis 101 and the power supply substrate 106 from each other, an insulation sheet 107 is disposed between the backlight chassis 101 and the power supply substrate 106, and also, the insulation sheet 107 is bonded to the bottom section 101a of the backlight chassis 101.
Patent Document 1: JP-A-2007-157451


By external data acquisition means using a computer, external data comprised of boundary data for an object is obtained; by external data input means, the external data are inputted into the computer; by cell dividing means, the external data are divided to rectangular parallelepiped cells that boundary planes intersect perpendicularly; by cell sorting means, the individual cells are sorted into boundary cells that include boundary data and non-boundary cells that do not include boundary data; by space sorting means, respective spaces are assigned to different space numbers where the cells are partitioned according to the boundary data; and by space number compression means, adjacent cells are reassigned to the same space numbers for cells that are not partitioned according to the boundary data.

1. Technical Field of the Invention
The present invention relates to a method and a program for cell labeling of volume data, for dividing space defined by boundary data that include one medium, or multiple-media, more than two, branching faces, holes, open shells, etc., and that are not always closed.
2. Description of the Related Art
In the research development or technology development field, CAD (Computer Aided Design), CAM (Computer Aided Manufacturing), CAE (Computer Aided Engineering) and CAT (Computer Aided Testing), for example, are employed as supporting means respectively for design, manufacturing, analyzing and testing.
Further, one set of volume data is co-owned to be used for sequentially performing different simulations, or for interacting simulation results with a manufacturing process, and this has gradually been spreading.
According to the conventional supporting means described above, the boundary face of a target or an objective article has an important meaning, and frequently, for example, the target is represented by using a boundary, and the inside of the boundary face is dealt with uniformly. In this case, inside/outside determining means is necessary for determining which is the inside or the outside of a two-dimensional or three-dimensional boundary plane or planes.
As conventionally known inside/outside determining means, there are (1) a ray crossing method (non-patent document 1), (2) a region growing (extending) method using boundary tracing (non-patent document 2), (3) a raster tracing in image processing (non-patent document 3), (4) a multi-directional tracing (non-patent document 2), (5) a method provided by Curless (non-patent 3), (6) a method provided by Szelistki or a method provided by Pulli, due to the use of an octree (non-patent document 5), and (7) non-patent documents 6 and 7 and patent documents 1 through 3. Furthermore, relevant patent documents 4 through 7 are publicly disclosed by the applicant the same as that of the present invention.
[Non-patent Document 1]
J. O'Rourke, "Computational Geometry in C (Second Edition"), p. 246, Cambridge University Press, 1998
[Non-patent Document 2]
Rosenfeld & Kak, translated by Nagao, "Digital image processing", Modern Science Co., Ltd., pp. 332-357)
[Non-patent Document 3]
B. Curless and M. Levoy, "A Volumetric Method for Building Complex Models from range images.", In Proceedings of SIGGRAPH '96, pages 303-312, August 1996)
[Non-patent Document 4]
R. Szeliski. "Rapid octree construction from image sequences."
[Non-patent Document 5]
K. Pulli, T. Duchamp, H. Hoppe, J. McDonald, L. Hapiro, W. Stuetzle., "Robust meshes from multiple range maps." Proceedings of International Conference on Recent Advances in 3-D Digital Imaging and Modeling, May 1997, pages 205-211.
[Non-patent Document 6]
Yonekawa, Kobori and Hisatsuwa, "Shape modeler using spatial division model", Bulletin of Information Processing Society of Japan, Vol. 37, No. 1, pp. 60-69, 1996
[Non-patent Document 7]
Morimoto and Yamaguchi, "Recursive spatial division method and partial spatial classification, self crossings, and extension to overlapping curve", Journal of Information Processing Society of Japan, Vol. 37, No. 12, December 1996
[Non-patent Document 8]
Weiler, K., The radial-edge structure: A topological representation for non-manifold geometric boundary representations, In Geometric Modeling for CAD Applications, North-Holland, (1988), pp. 3-36.
[Non-patent Document 9]
Cavalcanti, P. R., Carvalho, P. C. P., and Martha, L. F., Non-manifold modeling: an approach based on spatial subdivision, Computer-Aided Design, 29(3), (1997), pp. 209-220.
[Patent Document 1]
Japanese Laid-Open Patent Application Publication No. H8(1996)-96025, "Graphic Processing Method And Appratus for Same"
[Patent Document 2]
Japanese Laid-Open Patent Application Publication No. H8(1996)-153214, "Method for Generating Three-dimensional Orthogonal Grating Data"
[Patent Document 3]
Japanese Laid-Open Patent Application Publication No. 2003-44528, "Forming Method for Surface Grid of an Object"
[Patent Document 4]
Publication of the Japanese Patent No. 3,468,464, "Method for Storing Substance Data Obtained by Integrating Shape and Physical Property"
[Patent Document 5]
Japanese Laid-Open Patent Application Publication No. 2003-330976, "Inside/outside Determining Method for Boundary Data and Its Program"
[Patent Document 6]
International Publication No. 03/048980 pamphlet, "Method for Converting Tree-dimensional Shape Data into Cell Inner Data And Conversion Program"
[Patent Document 7]
International Publication No. 03/073335 pamphlet, "Method and Program for Converting Boundary Data into In-cell Shape"
The ray crossings method disclosed in non-patent document 1 is a method in which, when an input boundary face is present, whether the number of points where light (a ray) emitted by a specific point crosses the boundary is an even number or an odd number is determined, and when the number of points is an even number, it is determined that the visual point of the light ray is located outside an object, or when the number of points is an odd number, it is determined that the visual point is inside an object.
However, this means employed can not be applied when the light ray happens to contact a boundary, because a repeated root is provided, and thus, only one intersection point is obtained, while originally there are two intersection points. Therefore, there is also a problem in that this method can not be employed when boundary information is insufficient (when CAD data is to be read from different software, the missing of data sometimes occurs due to different ways of using expressions or due to an error in numerical values).
The region growing (extending) method, which employs boundary tracing in the image processing, to which only boundary information is given, is disclosed, for example, in non-patent documents 2, 8 and 9. However, there are problems such that the speed is slow because the performance of the process is extended toward the entire of the image, and identification can not be correctly performed when surface information is inadequate.
Raster tracing in the image processing is disclosed in non-patent document 2, and is a method whereby boundaries and a region sandwiched between the boundaries are traced while cells are scanned along a coordinate axis, such as the X-axis. Correct identification can not also be achieved with respect to an image obtained by quantizing inadequate boundary information (not a closed surface).
As a method for avoiding this, there is multi-directional tracing (the non-patent document 2), which is, however, low in the efficiency thereof.
The method offered by Curless for the reverse engineering field (method for reconstructing surface information based on a group of measurement points) is a robust method whereby external information, such as regularly arranged measurement points and directions of a plurality of cameras relative to a measurement object, is employed to define, for the entire field, an implicit function that is based on distance, and surface information is reconstructed. This method is disclosed in the non-patent document 3.
However, the method by Curless has drawbacks in the amount of data and the calculation time because distance field calculation is required for all of the cells. Further, a problem in accuracy is also pointed out, such that a distance function can not be correctly calculated for a thinner structure than the size of a cell and a face having an acute angle. This problem also results in an erroneous determination in the process of identification.
The method offered by Szeliski that uses an octree (the non-patent document 4) and the method offered by Pulli (the non-patent document 5) are also methods whereby relations between range data (distance data) for the obtained several targets and cells obtained by dividing a space using an octree are classified into three object divisions, i.e., inside, outside and boundaries, to thereby reconstruct the boundaries. According to these methods, since a projection operation is employed for each cell, a problem is encountered such that the processing is cumbersome and time-consuming and accordingly, calculations become unstable during the projecting operation.
A means disclosed in the non-patent document 6 can eventually express only two media by using three types of cells, i.e., outside, boundary and inside cells. Further, a problem must be encountered in which the expression is comprised of only a shape expression and no physical property value can be provided.
A means disclosed in the non-patent document 7 is directed to an inside/outside determining method used for input and branching, and is limited to two-dimensional sequential and finite use. Further, while a directed graph is employed, as one problem, this can not be employed for multi-media, three-dimensional use or discontinuous use.
Furthermore, the patent documents 1 through 3 disclose an art applicable to only two media, but to neither one medium nor three or more multi-media, and also are not applicable to any complicated surface data.
Additionally, although the patent documents 4 through 7 by the present Applicant are applicable to multi-media as a whole, the following problems, however, exist.
(1) It is difficult for a space to which multi-media belong to be partitioned along a boundary in a complicated shape.
(2) A limit exists in a target (boundary data) that can be dealt with as volume data proposed by the patent document 4.
In other words, when two manifolds, which are completely closed solids, are boundary data, dealing of multi-media is enabled. However, it is difficult to deal with boundary data such that a plurality of faces are branched from one side, or boundary data such that a hole is opened or is discontinued in the middle, i.e., it is difficult to deal with a non-manifold boundary, such as in the cases of face branching, a hole, an open shell, only one media, or three or more multi-media, etc.
It should be noted that, in the present invention, a manifold and a non-manifold are two-dimensional boundaries, and a solid, a volume, a medium and affiliated spaces are three-dimensional regions.
The present invention is contrived to solve the above-described problems. That is, an object of the present invention is to provide a method and a program for cell labeling of volume data, in which it is possible to deal with, as input targets, not only two outside and inside media, which are provided by boundary data for two manifolds that are completely closed solids, but also boundary data for a non-manifold that includes, for example, one medium that has an open shell boundary, three or more multi-media, face branching and a hole, and whereby a space partitioned by them can be divided in a quick and robust manner.
In other words, the object of the present invention is to provide a method and a program for cell labeling of volume data, in which different material (medium) information is added to each partitioned space segment, so as to be regarded as VCAD data (volume data), and various simulations are coupled/continued, and whereby volume data to which information has been added (also changed in a time series) can be employed for manufacturing and for an inspection, such as a comparison with a real object and an evaluation.

Method and its program for cell labeling of volume data


Example embodiments provide methods, apparatuses, systems, computing devices, and/or the like for vetting USB device firmware via a USB-specific firmware analysis framework. In one example, a method is provided for analyzing firmware of a Universal Serial Bus (USB) device. The example method includes steps of receiving a firmware image extracted from the USB device, identifying signatures from the firmware image relating to USB operation, and building an expected model of operation of the USB device using the identified signatures and a database of operational information regarding USB devices. The example method further includes the steps of generating a recovered model of operation of the USB device based on the firmware image and the identified signatures, and comparing the recovered model of operation with the expected model of operation to identify unexpected or unknown behaviors. The example method may further include generating a report comprising the identified unexpected or unknown behaviors.

In recent years, the Universal Serial Bus (USB) protocol has become ubiquitous and is supported by a vast array of devices, from smartphones to desktop PCs, small peripherals, such as flash drives, webcams, or keyboards, and even control systems and other devices that do not present themselves as traditional computing platforms. This ubiquity allows for easy connecting of devices to data and power. However, attacks that exploit USB have become increasingly common and serious. As an example, the "BadUSB" attack exploits the open nature of the USB protocol, allowing the advertisement of capabilities that device users may not realize are present. A "BadUSB" device appears to be a benign flash drive, but advertises itself as having keyboard functionality when plugged into a victim's computer; the host unquestioningly allows such a capability to be used. The malicious device is then able to inject keystrokes to the computer in order to bring up a terminal and gain administrative access. Fundamentally, there is an inability to constrain device functionality within USB, coupled with a corresponding lack of ability to know what types of functionalities a device is capable of advertising and whether or not these are benign.
Current USB vetting systems are focused on preventing USB attacks at the protocol level, through isolation-based approaches such as sandboxing and virtualization or involving the user in the authorization process. These approaches rely on a device's external actions to demonstrate its trustworthiness. Without a deeper understanding of the underlying software controlling these devices, an external observer cannot with certainty ensure that a device is trustworthy. Even solutions such as signed firmware give little evidence of its actual validity; signing merely demonstrates that an entity has applied its private key to a firmware, but does not in itself provide any assurance regarding device integrity. Consequently, there is limited ability to validate the trustworthiness and integrity of devices themselves using traditional techniques.
USB's greatest feature, its openness and expandability, is also its weakness, and attacks such as "BadUSB" exploit the unconstrained functionality afforded to these devices as a vector for compromise. Fundamentally, it is currently virtually impossible to know whether a USB device is benign or malicious.

Method and apparatus for vetting universal serial bus device firmware

UNIVERSITY OF FLORIDA RESEARCH FOUNDATION, INCORPORATED