Partially homomorphic encryption systems may be transformed into fully homomorphic encryption systems. Input plaintext data are transformed into modified plaintext data using a prime number operation and the modified plaintext data is then encrypted using any number of conventional encryption schemes. Desired computations on the encrypted data are transformed into homomorphic operations, based on the nature of the encryption format, and the homomorphic operations are applied to yield manipulated encrypted data. The manipulated encrypted data may be decrypted and the decrypted plaintext data may be modified into final, output plaintext data using a similar prime number operation as applied during encryption.

The demand for privacy of digital data and algorithms for handling more and more complex structures has increased dramatically over the last decade. This demand goes hand in hand with the growth in communication capacity and its diverse applications. For securely storing and accessing both data and networks current technology offers several alternatives, such as encrypting data or data communication pathways. However critical problems arise when one needs to perform operations on the encrypted data or to enable the modification and/or the branching of various algorithms depending on the outcome of certain computations. In such cases, the encrypted data needs to be decrypted, processed as needed, and then re-encrypted, thereby exposing the encrypted data to potential misappropriation and theft.
For example, data storage and computing services such as cloud services provide a low cost solution to users to use their large shared resources for data storage and management. Cloud computing provides almost unlimited computing power to its users. It also provides other potential benefits to users in terms of instant availability, scalability and resource sharing. Cloud service provides offer the following cloud services to users which includes online file storage (for example, Dropbox), social networking sites (for example, Facebook), webmail (for example, Gmail), and online business application (for example, Brokerage). Although cloud computing has become a mature service model, the adoption of its services by customers (businesses, consumers) is limited by concerns about a loss of privacy of their private data.
Encryption of data could solve this issue, but if the clients want to manipulate their encrypted data in the cloud, they have to share the secret key with cloud provider to decrypt it before executing the required operations. In another approach of processing encrypted data, the encrypted data is transmitted back from the cloud to a client side, decrypted at the client side to process the resulting unencrypted data. This approach leads to several security issues as the cipher text is continuously exposed. Furthermore, if the computations are performed at the client side, the main objective of using the cloud computing is not achieved.
Homomorphic encryption is an appropriate solution to solve security issues, such as those related to cloud computing, since its schemes enable the performing of computations on encrypted data without sharing the secret key needed to decrypt the data. Specifically, in a homomorphic encryption system, if one encrypts plaintext data (P1) to yield encrypted data (E1), and then applies the same function to encrypt P2 to get E2 it follows that if E3 is computed through a specific polynomial function of E1 and E2, and, when decrypted, yields P3, then the same polynomial function applied to P1 and P2, would result in P3.
Homomorphic encryption can be categorized under three types of schemes with respect to the number of allowed operations on the encrypted data as follows: 1) Partially Homomorphic Encryption (PHE) allows only one type of operation with an unlimited number of times (that is, no bound on the number of usages); 2) Somewhat Homomorphic Encryption (SHE) allows a restricted set of operations a limited number of times, and 3) Fully Homomorphic Encryption (FHE) allows unlimited number of operations with unlimited number of times.
U.S. Pat. No. 8,565,435, issued on Oct. 22, 2013 to International Business Machines Corporation, discloses a partial homomorphic encryption and decryption method. However, the disclosed partial homomorphic system has numerous disadvantages that prevent it from being practically useful. For example, the partial homomorphic system is not homomorphic for operations other than multiplication and addition. Additionally, for the number of multiplication operations or the number of addition operations it is capable of doing, it is highly limited, resulting in only a SHE system.
Second, the disclosed partial homomorphic system attempts to mimic a fully homomorphic encryption system by using a technique called bootstrapping. In bootstrapping, a user homomorphically encrypts the key along with the message and when the ciphertext degrades as a result of too many addition or multiplication operations, the ciphertext is decrypted and then re-encrypted to remove the degradation. This dramatically increases the amount of memory, time, and processing needed to use the encrypted data.
Third, prior art attempts at homomorphic systems are not capable of operating rapidly enough to be commercially useful. For example, to encrypt 2 bytes (16 bits) of plaintext data and process it in its encrypted form can take up to 30 minutes of processing time on a multi-GHz CPU using prior art homomorphic approaches. Key generation can take even longer time and require multiple gigabytes of storage for only a 16-bit word encryption. Almost all servers, PCs and even smart phones now are built using either 64-bit or 32-bit CPUs. Going from 16-bit processing to 32-bit processing would require exponentially greater time and memory. Clearly, this performance metric effectively negates any practical application of existing homomorphic systems.
Also, a bottoms-up approach to developing an FHE scheme involves: choosing a well-defined and intensively researched hard mathematical problem. Based on this difficult mathematical problem, the following components need to be developed: Designing and Analysis of Key Generation Function, Designing and Analysis of Encryption Function, Designing and Analysis of Decryption Function, and Designing and Analysis of Evaluation Functions on encrypted data. This approach also requires addressing the following issues: development of security proof of the FHE scheme, and implementation of the FHE scheme on different hardware platforms with timing benchmarks. This approach for the designing of the FHE scheme requires considerable time and effort. Also, a challenge is for the security of the FHE scheme to stand a test of time. The cryptographic community spends years with a new cryptosystem before the community and the industry accepts the system as secure.
Accordingly, there is a need for a homomorphic encryption method that is scalable, can be used to rapidly and efficiently encrypt and decrypt, can also be used to rapidly and efficiently process encrypted data and can also operate over more than multiplication and addition, while at the same time being conservative with its need for computational space and processing power. The encryption function also needs to be very difficult to invert or break, while also allowing for various types of public and/or private key generation protocols to be supported without undermining homomorphism, speed, memory use, complexity or semantic security.
Additionally, there is also a need to take an existing conventional third-party cryptosystem that is already in use and considered to be secure by the cryptographic community and the industry in general and convert that into a highly efficient fully homomorphic solution. Stated differently, there is a need to enable homomorphic transformations of encrypted data, which is plaintext data encrypted with a conventional cryptographic scheme, such that operations can be performed on the encrypted data without first decrypting the data and yield the same result as if the operations were performed on the underlying plaintext data.

Systems and methods for implementing an efficient, scalable homomorphic transformation of encrypted data with minimal data expansion and improved processing efficiency


An image stabilizing device removably mountable on a camera or other optical apparatus includes an image stabilizer for accomplishing image stabilization of the camera, a detector for detecting the operative state of the camera, and a controller responsive to the detector to control the operation of said image stabilizer. The detector detects the presence or absence of an information signal and the controller acts diversely dependent on the detections.

1. Field of the Invention
This invention relates to an image stabilizing adapter device for a camera mounted on the camera to accomplish the image stabilization of the camera.
2. Related Background Art
In recent years, the automatization of functions has advanced in photographing apparatuses such as video cameras so that even persons unskilled in photographic technique can accomplish good photographing by the automatization of focusing and aperture control. However, in spite of various proposals having been made with regard to the trembling of photographed images attributable to the trembling of the photographing apparatus, there has not yet been realized any simple and inexpensive image stabilizing device.
Generally, an image stabilizing device is comprised of trembling amount detection means for detecting the amount of trembling of the entire photographing apparatus, a correcting optical system for correcting the trembling of a photographed image caused by said trembling, calculation means for calculating the amount of driving of said correcting optical system in conformity with the output of said trembling amount detection means, driving means for driving said correcting optical system, control means for operating each of said various means in good order, and power supply means for supplying electric power to all of said various means.
However, where the constituents as described above are incorporated into the photographing apparatus, the image stabilizing device cannot be removed from the photographing apparatus body, and this leads to the following problems:
1) Portability and operability are sacrificed when the image stabilizing function is unnecessary; and PA1 2) The entire product must be designed in a form including the image stabilizing device, and this results in an increase in design cost and production cost.
On the other hand, where the image stabilizing device is made into a removable adapter type to eliminate the above-noted problems, there arise the following problems.
The image stabilizing device does not have means for discriminating the operative state of a camera on which the device is mounted and therefore, the starting and stoppage of the image stabilizing device must be effected with a discrete switch provided on the adapter side. For this reason, the photographer must effect the starting of the camera body side and the starting of the image stabilizing device side discretely from each other each time it effects photographing, and this means a cumbersome operation. So, it is also conceivable to newly provide on the camera body side a terminal exclusively for sending a signal to the image stabilizing device, but in such case, the camera must be designed in advance on the assumption that the image stabilizing device is mounted on the camera side, and this gives rise to an increase in design load and moreover an increase in cost. In addition, the existing product does not have such a function and thus, in that case, the image stabilizing device cannot be used.
Also, the image stabilizing device has a power source discrete from the power source of the photographing apparatus, and this results in an increase in the dimensions and weight of the photographing apparatus. Since in this case, the power source of the image stabilizing device and the power source of the photographing apparatus differ from each other, the timing at which the power source is consumed up differs between the two, and this also leads to the secondary disadvantage that there occurs a case where although image stabilization can be accomplished, photographing cannot be accomplished, or a converse case and the power sources cannot be effectively utilized.
Further, if the power source of the image stabilizing device is made common to the power source of the photographing apparatus, the photographing apparatus body or the power source of the photographing apparatus must be designed with the power supply to the image stabilizing device taken into account, and this leads to increased design and production costs.

Image stabilizing device operable responsively to a state of optical apparatus using the same


A feet position guidance aid for formulating individually formed thermoplastic insoles, shoes or shoe sole structures. The feet position guidance aid is made of flexible material and its upper surface includes guiding places for feet for guiding the position of the feet. The feet position guidance aid includes a lifter, wherein the lifter is a rising structure arranged to lift up and support the toes of the feet so that feet are guided to a position suitable for formulating the individually formed thermoplastic insole. An insole customizing arrangement for formulating individually formed thermoplastic insoles is also described.

Many people suffer from some sort of foot problems. An individual takes around 15 000-16 000 steps every day. Foot motion/gait problems reflect to soles, ankles, knees, hips, back, etc.; that is why their treatment and prevention is particularly beneficial to the whole human well-being. Provided that the foot position is correct, the load of the body is divided evenly and many problems caused by motion/gait can be avoided.
Different (arch) support insoles are available for correcting the foot position. Ready-made supports in the insoles do not generally provide a perfect match to anyone's feet, as people do not generally bear identical feet shape. Accordingly, many support insoles are ultimately deemed inconvenient due to their lousy fit. Only few of the people suffering from foot problems have had a chance to purchase insoles that alleviate at least part of the problems. Traditionally, custom-made shoes and insoles have been manufactured by professional shoemakers, physiotherapists, or podiatrists. Measuring the feet and manufacturing the insoles requires experts and/or expensive and specialized apparatuses.


According to the present invention, a method is provided for forming contact vias in an integrated circuit. Initially, a first protective layer is formed on an insulating layer, and an opening is created through the insulating layer where a contact is to be made. A conductive layer is deposited over the protective layer and partially fills the opening, forming a conductive plug in the opening. A second protective layer is then formed over the conductive plug. Portions of the conductive layer which were formed over the first protective layer are removed. During removal of those portions of the conductive layer, the second protective layer protects the conductive plug from damage. The first and second protective layers are then removed, leaving the conductive plug in the opening in the insulating layer. A conductive contact can now be made by depositing a second conductive layer over the conductive plug.

1. Field of the Invention
The present invention relates generally to integrated circuits, and more specifically to a method for forming contact vias in integrated circuits.
2. Description of the Prior Art
As integrated circuit devices become more complex, greater numbers of interconnect levels are required to connect the various sections of the device. Generally contact vias are formed between interconnect levels to connect one level to another. When multiple layers of interconnect are used in this manner however, difficulties arise in forming upper interconnect levels and contact vias due to the uneven topographical features caused by the lower interconnect levels. Thus, the topography of interconnect layers affects the ease of manufacturing of the integrated circuit device.
The uneven topographical features of multiple interconnect levels are caused by forming the various interconnect layers above each other, resulting in the creation of hills and valleys on the surface of the device. Those skilled in the art will recognize it is difficult to get upper interconnect layers to maintain constant cross-sections when crossing over uneven topography. This leads to portions of the interconnect lines having a higher current density, leading to electromigration problems and related device failure mechanisms. These step coverage problems can result in voids and other defects in the interconnect signal lines themselves, and in the contact vias formed between interconnect lines.
Therefore, it would be desirable to provide a method for forming contact vias which are free of voids and other defects, and which result in a more planar topography. It is also desirable that such a method not significantly increase the complexity of the manufacturing process.

Method for forming contact plugs in integrated circuits


A hybrid coupling for a smart battery system having two internal batteries. The hybrid power coupling includes a power coupling for connecting to the batteries and a data coupling for connecting with two bus devices that are also within the battery housing. The contacts of the digital data coupling are disposed in a circular configuration within the mating jack of the hybrid coupling. The data contacts are concentric with the D.C. battery contacts. The data contacts are retractable to automatically and selectively connect to a variety of battery-mounted jacks.

1. Field of the Invention
The invention relates to a hybrid coupling for a smart battery and a battery system incorporating such hybrid coupling.
2. The Prior Art
In the past, smart or rechargeable batteries were connected to external devices, like communications devices and chargers through power couplings. In certain demanding environments, such as military applications, it was desirable to accurately track battery state-of health, state-of-charge, usage statistics and the types of devices that were connected to the battery. Thousands of batteries, radios and chargers were deployed. Batteries that are not smart-enabled, are referred to in this application as "basic batteries." Rechargeable batteries may also be referred to as secondary batteries, compared to primary batteries which are single use.
When smart batteries were first introduced, they needed to be backward compatible to the basic radios and charges they might be connected to in the field. As a result, an independent bus connector was added to the battery that was separate from the power coupling. All devices could connect to the power coupling, and those connecting devices that were smart, could selectively connect to the separate bus connector. The provision of separate connectors has continued to many modern applications. For example, U.S. Pat. No. 6,262,562 shows in FIG. 1B the battery power coupling 158 separate from the system management (SM) Bus connectors 184. Also, U.S. Pat. No. 6,509,717 discloses a smart battery for a laptop. The prior art illustration of FIG. 2 shows the charging unit 7 separate from the SM Bus coupling between the smart batteries 3,4 and unit 5. FIG. 3B shows connector configurations for tandem smart battery packs. Finally, in FIG. 4 illustrating the invention, the charging unit 70 connects to the Vbat battery separate from the SM bus connection between SM bus host 20, battery selecting unit 50 and batteries 30, 40.
Communications, formats and protocols used with smart batteries are derived from the SMBus specifications, that is Smart Battery System Specifications, System Management Bus Specifications
Accordingly, it would be desirable to provide a single coupling that incorporates the SM Bus data coupling into multi-battery power coupling.

Hybrid coupling for a smart battery system


A method for establishing an aging model of a device is provided. The device is measured to obtain degradation information of the device under an operating condition, wherein the device is a physical device. The degradation information is partitioned into a permanent degradation portion and an impermanent degradation portion. The impermanent degradation portion is differentiated by time to obtain a differential value. The aging model is obtained according to the differential value. When the differential value is greater than zero, a degradation of the device increases over time, and when the differential value is less than zero, the degradation of the device decreases over time.

System-on-chip (SoC) technology is integrating multiple functional blocks on a single silicon chip. The multiple functional blocks may include digital circuits, analog circuits, mixed-signal circuits or any combination thereof. This technology reduces the development cycle and manufacturing costs while increasing product reliability, functionality and performance.
As semiconductor devices advance to submicron sizes, integrated circuit design margins have become very small. Therefore, a proper estimate of aging-induced defects will help designers optimize design margins so as to achieve a balance between reliability and cost. Simulation tools such as Simulation Program with Integrated Circuits Emphasis (SPICE) can be used to simulate aging-induced defects. However, it is not widely known how degradation mechanisms propagate in a SoC chip as a function of a variety of operating conditions. Thus, an aging model is needed to predict semiconductor degradation.

Method for establishing aging model of device and analyzing aging state of device with aging model

TAIWAN SEMICONDUCTOR MANUFACTURING CO., LTD.


Hydrocarbons are preheated, particularly for a hydrodesulfurization process by first heating the hydrocarbon stream to produce a vapor and a liquid stream, thereafter superheating at least some of the vapor phase and mixing the superheated vapor phase with the liquid phase to generate the hydrocarbon feedstream at the desired temperature. By this procedure only the evaporated hydrocarbons are subjected to a high temperature, but not the heavier hydrocarbons.

In several hydrocarbon processes and process steps, it is necessary to heat the hydrocarbon. To obtain well-defined conditions and a controllable operation it is frequently desirable to be able to heat or preheat hydrocarbons without hydrocarbon conversion, or at least without inaccurately defined hydrocarbon conversion and without side reactions leading to polymers, gums, and other undesired by-products.


A blade is provided for a turbine engine that includes an exterior surface. The exterior surface includes a portion having a thermal barrier coating and an uncoated shelf adjacent to the thermal barrier coating without the thermal barrier coating. A cooling hole extends from an internal passageway through the exterior surface to an exit. A scarfed channel is recessed in the exterior surface and interconnected to the cooling hole at the exit. The scarfed channel extends to a blade tip end surface. The scarfed channel protects the cooling fluid exiting the cooling hole from secondary flows surrounding the blade that would otherwise mix with and disperse the cooling fluid. The scarfed channels also increase the surface area exposed to the cooling fluid to increase the heat transfer rate.

This application relates to turbine engine blades. More particularly, the application relates to thermal barrier coatings and cooling holes for use with turbine engine blades.
High heat loads exist between the tip of a turbine engine blade and its shroud. The tip temperature for a high pressure turbine blade, for example, can be a limiting factor in the design and operation of a turbine engine. As a result, efforts are made to reduce the temperatures at the blade tip.
One prior art tip cooling approach uses a thermal barrier coating at the tip to reduce the heat flux at the tip. Another approach provides tip cooling holes that apply a film of cooling fluid in the vicinity of the tip. Another approach is to provide machined pockets at the tip to reduce heat transfer in the area, retain the cooling flows and reduce the volume of metal at the tip that needs to be cooled. One or more of these cooling approaches may be applied to a particular blade to achieve lower blade tip temperatures.
Despite the use of the approaches described above, undesirably high tip temperatures exist. Heat loads within the pocket are typically higher than desired. External surfaces are typically covered with thermal barrier coatings to reduce the heat flux. However, lower metal temperatures can be achieved by removing the thermal barrier coating at the tip, which forms a shelf that increases film effectiveness in the area. While this has been achieved in the prior art, it is unknown what techniques have been employed to provide the shelf. What is needed is a further reduction in blade tip temperature.


A digital power supply protection circuit includes: a signal preprocessing circuit, configured to receive an overcurrent signal and a first inceptive impulse clock timing, and perform preprocessing on the overcurrent signal according to the first inceptive impulse clock timing so as to obtain a first reference signal a signal generation circuit, configured to receive the first inceptive impulse clock timing, count time duration between a rising edge of the first inceptive impulse clock timing and a rising edge of the first reference signal so as to obtain a first time duration, and upon the first time duration is greater than a second time duration, generate a first disabling signal by delaying the rising edge of the first inceptive impulse clock timing for the second time duration; and a clock timing adjustment circuit, configured to adjust the first inceptive impulse clock timing according to the first disabling signal.

In a direct current to direct current power conversion circuit, a bridge circuit is a common application circuit, and the bridge circuit includes a full bridge circuit and a half bridge circuit. The bridge circuit periodically works under control of an inceptive impulse clock timing, and each period is divided into the first half period and the second half period. A power switch in the bridge circuit is classified into two groups: a power switch that is switched on at a first time and a power switch that is switched on at a second time, and the two groups of power switches are switched on in different half periods.
As shown in FIG. 1, a typical full bridge circuit includes a first power switch, a second power switch, a third power switch, a fourth power switch, a transformer K1, a DC blocking capacitor C1, a first synchronous rectifier, a second synchronous rectifier, a sampling resistor R1, a filter inductor T1, and a load. A specific connection relationship is shown in FIG. 1. In the first half period of a period, the first power switch and the fourth power switch are switched on, and the second power switch and the third power switch are switched off. In the second half period of the period, the first power switch and the fourth power switch are switched off, and the second power switch and the third power switch are switched on. The first power switch and the fourth power switch are power switches that are switched on at the first time in the full bridge circuit, and the second power switch and the third power switch are power switches that are switched on at the second time in the full bridge circuit.
As shown in FIG. 2, a typical half bridge circuit includes a fifth power switch, a sixth power switch, a transformer K2, a DC blocking capacitor C2, a first synchronous rectifier, a second synchronous rectifier, a sampling resistor R1, a filter inductor T1, and a load. A specific connection relationship is shown in FIG. 2. In the first half period of a period, the fifth power switch is switched on, and the sixth power switch is switched off. In the second half period of the period, the fifth power switch is switched off, and the sixth power switch is switched on. The fifth power switch is a power switch that is switched on at the first time in the half bridge circuit, and the sixth power switch is a power switch that is switched on at the second time in the half bridge circuit.
For a bridge circuit, to maintain magnetic balance of a transformer, a DC blocking capacitor (such as the C1 in FIG. 1 and the C2 in FIG. 2) is generally connected in series on a primary side of the transformer, and a switch-on time duration of a power switch that is switched on at the first time and a switch-on time duration of a power switch that is switched on at the second time are controlled to be equal in each period, so that a charging time duration and a discharging time duration of the DC blocking capacitor connected in series on the primary side of the transformer are equal, thereby implementing magnetic balance of the transformer. However, when an overcurrent occurs in the bridge circuit, to implement magnetic balance of the transformer, the following technical solutions are generally used.
In the prior art, in a current period, when an overcurrent signal occurs within a switch-on time duration of a power switch that is switched on at the first time, an active level that controls the power switch that is switched on at the first time to a switch-on state is adjusted to an inactive level according to time of occurrence of the overcurrent signal; when no overcurrent signal occurs within a switch-on time duration of a power switch that is switched on at the second time, or when an overcurrent signal also occurs within the switch-on time duration of the power switch that is switched on at the second time, relative to start time of a switch-on time duration of a power switch, if time of occurrence of the overcurrent signal occurring at the second time is later than the time of occurrence of the overcurrent signal occurring at the first time, an active level that controls the power switch that is switched on at the second time to a switch-on state is also adjusted to an inactive level according to the time of occurrence of the overcurrent signal occurring at the first time, so that when an overcurrent signal occurs, it may be ensured that in the current period, the switch-on time duration of the power switch that is switched on at the first time is equal to the switch-on time duration of the power switch that is switched on at the second time, thereby implementing magnetic balance of a transformer. The active level is used to control a power switch to a switch-on state, and the inactive level is used to control the power switch to a switch-off state. For example, the active level may be at a high level, and the inactive level may be at a low level, which depends on a type of a transistor in the power switch and a specific circuit design of the power switch.
However, in the foregoing implementation process, if no overcurrent signal occurs within the switch-on time duration of the power switch that is switched on at the first time in the current period, but an overcurrent signal occurs within the switch-on time duration of the power switch that is switched on at the second time, to ensure that a bridge circuit is not damaged, only the active level that controls the power switch that is switched on at the second time to a switch-on state and is in the current period is disabled according to time of occurrence of the overcurrent signal, but a subsequent signal is not processed according to the current overcurrent signal, which finally causes duration of the disabled active level of the power switch that is switched on at the second time in the current period to be different from duration of the active level of the power switch that is switched on at the first time in the current period. In addition, the subsequent signal is not further processed subsequently; therefore, magnetic balance of the transformer cannot be ensured, thereby reducing reliability of the bridge circuit.

Digital power supply protection circuit, and apparatus


A hill start assist system for a tractor includes a pressure reduction valve receiving air from an air supply source, a solenoid valve having a supply port connected to a delivery port of the pressure reduction valve, a double check valve receiving air from a foot brake valve and from the solenoid valve, a tractor protection valve receiving air from the solenoid valve and from front and rear brake circuits of the tractor and an inversion valve having a control line connected to the solenoid, a supply port connected to the delivery line of the tractor protection valve, an exhaust port connected to the foot brake valve and a delivery line connected to a stop light switch.

This invention relates to tractor-trailers and more particularly, to trailers that include a hill start assist function.
Tractor-type trucks are designed to tow trailers and semi-trailers having large loads. The loads may include goods, supplies or other freight. Some tractor trucks include an automated manual type transmission. This type of transmission presents a challenge to operators of the trucks when the truck has to accelerate from a stationary position on an incline.
In order to stop or maintain a stationary position (at a traffic light for example), the brakes are applied. When the truck has to accelerate from this position, the operator has to shift his or her foot from the brake pedal to the accelerator pedal. However, during this transition period, the truck has a tendency to roll back (if moving forward) as a result of the brakes being released since the driveline does not become engaged instantly upon a depression of the accelerator pedal. This rollback may be due to the incline (or grade) of the road, the load or weight of the truck or a combination thereof.
Hill start assist systems have been developed to prevent rolling back of the vehicle during the transition period. The present systems, however, do not provide adequate protection against the rolling back of a truck. Some systems only use brakes of the tractor portion of the truck to keep the truck from moving or rolling back. These systems do not use trailer brakes to assist in holding the truck in a stationary position on an incline. The brakes of the tractor may not be able or adequate to hold the tractor trailer combination on the grade. The brakes of the tractor may also wear out faster in these systems. In some situations (e.g. particular inclines), the present systems also do not keep even a tractor (without an attached trailer) from rolling back during this transition.
What is desired, therefore, is a hill start assist system that provides adequate protection against the rolling back of a truck that is transitioning from a stationary position.


An improved discriminating circuit breaker system for use with an electrically grounded direct current power distribution system. A three-tier safeguard system is provided to insure proper operation of the breaker should a fault occur. The basic components include the electrically operated circuit breaker and a control circuit therefor. The control circuit sends a control signal to the breaker to operate it depending on whether a illegitimate load is detected on the power distribution system. This detection process utilizes: a pilot wire through which any control signal flows; an alternating current (a.c) signal generator to superimpose such a signal on the transmission line; a current detector to sense the a.c. level and produce a control signal if its current value exceeds a maximum level; a voltage detector to sense the voltage level of the a.c. signal and to produce a control signal if the value falls below a minimum level; and a switch system responsive to the control signals and in series with the pilot wire to activate the opening of the circuit breaker when the wire is open or when a control signal is produced.

Various types of systems for protecting direct current (DC) power distribution systems are known in the art. In one basic type of prior art system, which is exemplified by the system disclosed in U.S. Pat. No. 3,581,152 (Hunt), the direct current operating conditions of the distribution system being protected are monitored by voltage sensitive and/or current sensitive devices.
In another basic type of prior art system, which is exemplified by the systems disclosed in CERCHAR publication No. 1306, dated January, 1963 and published by an agency of the French government, and by the system disclosed in U.S. Pat. No. 3,946,279 (Paice et al), an alternating current (AC) signal is superimposed on the DC power signal, and faults are detected by monitoring the resultant alternating current. Since normal loads have substantial impedance at high frequencies (such as 3 KHz) and draw only a small high frequency current, whereas illegitimate loads such as arcing faults draw a substantial high frequency current, the presence of illegitimate loads are detected in such systems by the high frequency current they draw. However, the substantial inductance of mine power distribution systems makes it difficult for such protection systems to detect faults at points remote from the point at which the AC signal is superimposed on the distribution system. Attempts to overcome this problem have included (1) superimposing the AC signal at more points on the distribution systems, which has the disadvantage of requiring more oscillators and detectors; (2) reducing the impedance of the power transmission lines by running pilot wires with series capacitance parallel to the transmission lines, which is costly and difficult to implement effectively; and (3) increasing the ac impedance of legitimate loads, as exemplified by the Paice et al system, which requires significant quantities of vehicle mounted equipment, and is ineffective if the tranmission lines have a higher than normal impedance, as, for example, is caused by poor grounding or the like.
Applicant is also aware of two systems for detecting balanced ground faults in floating, or ungrounded, direct current electrical systems which employ voltage detectors. These systems are disclosed in U.S. Pat. Nos. 3,754,221 (Stetler) and 3,975,663 (Moorey). In the Stetler system, a resistance connected to each side of the floating circuit is also connected via a two-way switch to a grounded voltage detector, and the voltage drop across each resistance is measured alternatiely to detect faults. In the Moorey system, faults are detected by alternately applying first and second dc voltages having predetermined magnitudes to a ground terminal of the floating circuit which is connected to either side of an electrical supply for the floating circuit, and detecting changes in the magnitudes of the resulting voltages between the electrical supply and the ground terminal. However, in addition to requiring relatively complicated circuitry for their implementation, such systems are not readily adapted to protecting grounded power distribution systems.

Discriminating circuit breaker protection system direct current power distribution systems

The United States of America as represented by the Secretary of the Interior


A retainer receives and secures together the male and female terminal blocks of a pair of electrical cords where each cord includes an end segment that extends immediately from the male or female terminal blocks. The retainer includes a generally flat and rigid member having spaced apart first and second cord openings formed therein. A slit extends between the first and second cord openings and can be manipulated between closed and open positions. By opening the slit, the male and female terminal blocks can be inserted through the slit and the end segments extending from the terminal blocks can be moved along the slit and inserted into the cord openings. Consequently the end segments leading from the terminal blocks turn and extend through the cord openings such that the end segments are maintained out of general alignment with the male and female terminal blocks. Accordingly when tension is placed on the two electrical cords, the orientation of the end segments leading from the male and female terminal blocks tends to prevent the terminal blocks from being pulled apart.

Electrical cords are widely used to extend access to electrical power beyond fixed outlets such as those found in and around residential and commercial buildings. Typically an electrical cord will have a male terminal block and a female terminal block and a pliable cord extending therebetween. In some cases it is common practice to connect two or more electrical cords together. This is often done by a person operating an electric leaf blower, hedge trimmer or lawn mower, for example. In the case of a leaf blower, for example, one of the most frustrating and aggravating occurrences when utilizing two or more electrical cords connected in series occurs when the operator happens to place a tension on the cords and causes a male terminal block of one cord to be pulled from the female terminal block of another adjoining cord. This obviously requires the operator to cease blowing leaves and return to the area where the disconnected cords can be retrieved and reconnected.
The separation of the cords can occur in various ways. In some instances, one part of the connected cords can become hung on a shrub or other obstacle and as the operator attempts to free the cords from the obstacle, he or she will pull or place a tension on the cord causing the male and female terminal blocks of two cords to be disconnected. In other cases the operator may be approaching the full extension of the two or three connected cords being utilized. The cords will only extend so far, and the operator of the work piece connected at the end of the cords often find himself or herself operating in an area and the cords are fully extended. Sometimes in these cases, the operator will attempt to carry the electrical devices, such as a leaf blower, further than the cords will permit. In doing so the operator will place a tension force on the cords and this tension force will be sufficient to cause the male and female terminal blocks of the cords to become disconnected.
Devices are known for retaining the male and female terminal blocks of two electrical cords together. For example, see the disclosure in U.S. Pat. Nos. 5,732,445 and 4,957,450. While these retainers do function to secure the male and female terminal blocks of two electrical cord together, they are generally difficult to use or overly complex.
There has been and continues to be a need for a relatively simple retainer for securing connected male and female terminal blocks of two electrical cords together such that if a tension force is applied on the connected electrical cords that the retainer will prevent the male and female terminal blocks from being pulled apart.

Retainer for securing two connected electrical cords


An exhaust gas recirculation (EGR) cooler includes a plurality of tubes and a shell enclosing the tubes. During use, cooling water is supplied to and discharged from the shell, and exhaust gas is guided from a diesel engine into the tubes to be heat exchanged with the cooling water. An inner periphery of each of the tubes is formed with three streaks of spiral protrusions running without crossing and with phases peripherally shifted to each other. A pitch P ratio of each of the spiral protrusions to an inner diameter of each of the tubes is 2.0-4.0, and a ridge height H ratio of each of the spiral protrusions to the inner diameter of each of the tubes is 0.1-0.2.

Known is an EGR apparatus which recirculates part of exhaust gas from an engine in a vehicle or the like to the engine to suppress generation of nitrogen oxides. Some of such EGR apparatuses are equipped with, midway of an exhaust gas recirculation line to the engine, an EGR cooler for cooling the exhaust gas since cooling the exhaust gas to be recirculated to the engine will drop the temperature of and reduce the volume of the exhaust gas to lower the combustion temperature in the engine without substantial decrease in output of the engine, thereby effectively suppressing generation of nitrogen oxides.
FIG. 1 is a sectional view showing an example of the EGR coolers in which reference numeral 1 denotes a cylindrical shell with axially opposite ends to which plates 2 are respectively fixed to close the ends of the shell 1. Penetratingly fixed to the respective plates 2 are opposite ends of a number of tubes 3 which extend axially within the shell 1.
Attached to the shell 1 from outside are cooling water inlet and outlet pipes 4 and 5 near one and the other ends of the shell 1, respectively, so that cooling water 9 is fed via the inlet pipe 4 into the shell 1, flows outside of the tubes 3 and is discharged via the outlet pipe 5 outside of the shell 1.
The respective plates 2 have, on their sides away from the shell 1, bowl-shaped hoods 6 fixed to the respective plates 2 so as to enclose end faces of the plates. The one and the other hoods 6 provide central exhaust-gas inlet and outlet 7 and 8, respectively, so that exhaust gas 10 from the engine enters via the inlet 7 into the one hood 6, is cooled during passage through the number of tubes 3 by means of heat exchange with cooling water 9 flowing outside of the tubes 3 and is discharged to the other hood 6 to be recirculated via the outlet 8 to the engine.
In the figure, reference numeral 11 denotes a bypass outlet pipe arranged at a position diametrically opposed to the cooling water inlet pipe 4, part of the cooling water 9 being withdrawn through the bypass outlet pipe 11 so as to prevent the cooling water 9 from stagnating at the position diametrically opposed to the cooling water inlet pipe 4.
Such conventional EGR cooler has poor heat exchange efficiency since the exhaust gas 10 may flow straight in the tubes 3 and insufficiently contact inner peripheries of the tubes 3. Therefore, it has been proposed that an inner periphery of each of the tubes 3 is formed with spiral protrusions to causes the exhaust gas 10 passing through each of the tubes 3 to whirl, thereby increasing contact frequency and contact distance of the exhaust gas 10 to the inner periphery of each of the tubes 3 to enhance the heat exchange efficiency of the EGR cooler (see, for example, References 1 and 2).                [Reference 1] JP 2000-345925A        [Reference 2] JP 2001-254649A


Systems, methods, and computer-readable executable instructions are provided for implementing an energy proportional network architecture. Implementing an energy proportional network architecture can include determining a number of desired network criteria and a desired number of access ports. A number of switches for the energy proportional network architecture can be calculated from the desired number of access ports and the number of desired network criteria. Implementing an energy proportional network architecture can also include using the number of calculated switches to form the energy proportional network.

Many network designs and deployments are designed as hub and spoke architectures. These hub and spoke architectures can include access ports for computing devices that can be connected to a closest switching hub. Network components (e.g., access ports, interconnection ports, linecards, and/or switches) can always be turned on and/or enabled, irrespective of the existence of traffic generating or receiving data. Networks can also utilize a few switches with large radix values and may be unable to achieve energy proportionality due to the inability in current designs to turn off the backplane portions incrementally in a load proportional manner.

Implementing an energy proportional network architecture from desired network criteria

Hewlett Packard Enterprise Development LP


The disclosed flow monitoring apparatus has a flow-varied sensing capacitance and an inductor in a series-resonant circuit that modulates the frequency of an oscillator. In one apparatus, the sensing capacitance comprises a flow-activated vaned rotor whose blades sweep past a very small capacitive sensing electrode, for monitoring flow rates. In other apparatus a flow-activated blade is biased to remain opposite a very small capacitive sensing electrode, to provide on/off flow indication.

Over the years, a substantial number of flow sensors have been developed that rely on a flow-activated element and one or more electrodes responsive to the flow-activated element. Some of those flow sensors rely on a range of conductivity of the fluid, thereby rendering them useless for sensing the flow of air and other gases and for sensing highly resistive or insulating liquids such as petroleum and its derivative liquids.
Some flow sensors involving sensing electrodes rely for their operation on the changes of capacitance occurring at a single sending electrode or electrode pair caused by a flow-activated element. Some of such flow sensors may be affected only incidentally by conductivity and other properties of the liquids to be monitored, but the intended dominant effect in such sensors is the capacitance changes caused by the flow-activated element at the sensing electrode(s).
"Capacitive flow sensors" (as they are called here) undergo changing capacitance at one or more sensing electrodes in response to flow-activated members in the sensing region. Among various known capacitive flow sensors are those which sense flow-induced capacitance changes at the sensing electrode(s) caused by an orbiting ball, and those which sense successive slender vanes of a flow-activated rotor such as a turbine rotor or a paddle wheel. A capacitive flow sensor may involve an array of sensing electrodes, or a pair of sensing electrodes, or a single localized sensing electrode, which are referred to below as "sensing electrode means".
An excellent form of capacitive flow sensor is one that relies on an inductance connected in series with the capacitance of capacitive sensing electrode means, disclosed in U.S. patent application Ser. No. 07/632,520,filed Feb. 13, 1991 and its continuation Ser. No. 08/020,908, filed Feb. 22, 1993 by Murray F. Feller. The sensing capacitance and the series-connected inductance form a series-resonant circuit, and the changing impedance of the series-resonant circuit due to alternating proximity and distance of each sensed flow-activated element relative to the sensing electrode modulates the amplitude of an excitation signal. Notably, that flow sensor is highly sensitive to the sweep of the edges of slender vanes or blades of a flow-driven rotor past a very small sensing electrode. A high degree of sensitivity is valuable in detection of the characteristically small capacitance changes at such small parts.
Maintaining that flow sensor in stable operation may require adjustments to take into account varied operating conditions, and stable operation may warrant limiting the Q of the series-resonant circuit which consequently limits the sensitivity of the apparatus. Moreover, for achieving greatest sensitivity there, a single sensing electrode is placed as close as is feasible to the path of flow-activated elements, consistent with practical limitations. The inherent shunt or stray capacitance of the sensing electrode (capacitance that is not caused to vary by the flow-activated elements) is minimized. This concern imposes its own exacting constraints on the practical design and construction of the sensing electrode and its connection to the series inductance.


A method of connecting to an existing wellbore downhole can include installing a swellable material into the existing wellbore from a connecting wellbore drilled into the existing wellbore. A well system can include a relief wellbore drilled proximate an existing wellbore, a connecting wellbore drilled from the relief wellbore to the existing wellbore, a tubular string extending from the relief wellbore through the connecting wellbore and into the existing wellbore, and a swellable material which swells in an annulus formed between the tubular string and at least one of the relief wellbore, the connecting wellbore and the existing wellbore. Another method of connecting to an existing wellbore downhole can include drilling a relief wellbore proximate the existing wellbore, then drilling a connecting wellbore from the relief wellbore to the existing wellbore, and then installing a swellable material into the existing wellbore from the connecting wellbore.

In some circumstances, an existing wellbore may become unusable, for example, due to structural issues (such as, casing collapse or parting, etc.) or fluid/pressure issues (such as, a blowout or poor cement integrity, etc.). However, a section of the wellbore may be salvageable for further production or injection use. Therefore, it will be appreciated that improvements are continually needed in the arts of constructing well systems and providing contingency measures in such circumstances. These improvements may be useful whether or not any section or all of an existing wellbore is considered usable.

Downhole communication between wellbores utilizing swellable materials


A soft polymeric clad glass fiber waveguide with an easy to handle, low-loss end termination is disclosed. Each end termination is formed with a pair of telescopically assembled plastic sleeves. The inner sleeve is heat bondable to the glass core and has a refractive index lower than the glass core. It replaces an end portion of the soft rubbery polymeric cladding. The outer sleeve is heat shrinkable and during the termination procedure functions to compress, center and confine the inner sleeve. After termination, it functions to stiffen the fiber end and strain relieve the junction between the soft polymeric cladding and the stiffer inner sleeve. A method for making such a waveguide termination is disclosed. Also disclosed is an environmentally sealed optical waveguide of related construction.

I. Field of the Invention
This invention relates generally to glass fiber optical waveguides. More specifically, the invention relates to those waveguides that propagate light at least in part through the mechanism of reflection at the interface between the exterior surface of a glass core and a polymer cladding, typically silicone rubber.
II. Description of the Prior Art
The past few years have witnessed the rapid emergence of fiber optic technology from laboratories around the world into a wide variety of commercial applications. This emerging technology has given rise to many inventions, patents, books and other technical publications. A recent and quite readable overview article which contains a glossary of the more commonly used electroptical terms is authored by L. Borsuk, and entitled "What All Connector Engineers Should Know About Fiber Optics", Insulation/Circuits, August, 1978, Pages 43-49. The Oct. 25, 1978 issue of Electronic Design contains a special report assessing fiber optic technology which begins on page 53 thereof. The above identified article and special report are both incorporated by reference herein.
The final design of any fiber optic information transmission system is a complex function of many system component characteristics and engineering tradeoffs. Although many optical waveguide constructions are known, the characteristics associated with each construction vary widely and, therefore, the type of waveguide used in any given system must be matched to that system's requirements.
One optical waveguide construction which offers a number of desirable attributes has a stepped refractive index profile. Such a profile is usually obtained when a homogeneous glass core, is surrounded by a lower refractive index cladding of glass or polymer. A waveguide so constructed propagates light through the reflection of rays at the interface between the exterior surface of the glass core and the cladding.
Another optical waveguide construction uses a core with a graded refractive index profile. Typically, such profiles are formed when the refractive index decreases outwardly from the center of the core. Such a waveguide propagates light through the refraction of rays at selected regions within the core. It is to be understood that a waveguide which propagates light at least in part through the reflection of rays at the interface between the exterior surface of the core and the cladding and at least in part through the refraction of rays at selected regions within the core can be fabricated and may be useful in certain applications.
Polymer clad step index glass fiber waveguides are relatively simple to fabricate compared to other waveguide constructions. They are relatively easy to launch light into because of their large numerical apertures (typically 0.2 to 0.4) and, in theory at least, should be easier to interconnect because their relatively large core diameters (typically 125 to 400 microns) can tolerate greater axial misalignment than waveguides with smaller core diameters (typically 5 to 75 microns). In addition, polymer clad glass fiber waveguides appear to be less susceptible to the adverse effects of ionizing radiation at levels in excess of 1 Mrad than other waveguide constructions.
Large core diameter, step index waveguides allow light to propagate in many modes. Some modes have longer optical paths to traverse than others. These unequal optical path lengths result in undesirable signal dispersion over long distances. Although such dispersion ultimately limits the signal bandwidth of such waveguides, there are many applications requiring a waveguide less than one kilometer in length where some signal dispersion at selected information transmission rates can be tolerated.
A variety of polymers have been used to form the cladding layer which surrounds the core. In particular, silicone base polymers have proven useful in cladding waveguides to achieve low levels of signal attenuation (less than 10 dB per kilometer when measured at 820 nanometers). However, two well known problems associated with prior art silicone clad glass waveguides have limited their more widespread use. First, the soft, rubbery nature of silicone base polymers renders waveguides clad with such materials, difficult if not impossible to terminate without significant signal losses. Second, the inability of silicone base polymers to function as an effective moisture barrier leaves the surrounded glass waveguide core vunerable to moisture enhanced stress cracking.
Prior art efforts to overcome these problems have not been successful. For example, attempts have been made to bond the silicone to a connector ferrule or other waveguide supporting structure. The strength of such a termination is inherently limited by the strength of the glass to silicone bond and/or the shear strength of the silicone material itself. In addition, because the glass core is not securely held, it is subject to some axial, radial and rotational displacement when a remote portion of the waveguide cable is moved such as by twisting, coiling or pulling. In the situation where a waveguide is terminated in abutment to an optical source or detector, such as a light emitting diode, laser diode, photo transistor or the like, even a small amount of fiber end displacement can result in damage to these components. Fiber end motion in a waveguide connector can make the connection losses a variable function of waveguide cable placement. Moreover, in terminating a silicone clad waveguide in a connector, two additional considerations should be kept in mind. First, to achieve a low loss connection between two waveguides, it is essential that the longitudinal axes of their cores be closely aligned. Although their alignment can be accomplished in many ways, one of the most attractive is to employ a connector with an aligned bore which centers the glass core therein. As a practical matter, such centering is difficult to achieve with a silicone clad waveguide as the outside diameter and concentricity of the cladding must be precisely controlled to just fit within the connector bore while at the same time the core must be precisely centered within the cladding. Second, assuming the waveguide has been centered and secured within the connector bore, it is still necessary that the end surface of the core possess an optically smooth finish. Such a surface can be obtained by either cleaving the glass core or by polishing the end with a series of increasingly fine abrasives. Although cleaving can provide a very smooth finish, abrasive polishing is generally preferred because the polishing operation can be used to accurately establish a predetermined relationship between the core end and the connector body thereby providing better control of the lateral spacing between aligned core end surfaces. One problem encountered in the prior art when attempting to polish a core end is that the surrounding silicone cladding is too soft to provide adequate support. Therefore, the core is allowed to bend back and forth during polishing. This motion frequently causes the edge of the core to chip and break. At best, the core end becomes polished with a slightly convex rather than flat surface which increases attenuation.
Attempts have been made to avoid some of these problems by using silicone base polymers with a variety of additives to make the cladding stiffer and therefore easier to work with. These attempts have all adversely effected the overall attenuation characteristics of the waveguide.
It would appear that using a hard and rigid low refractive index polymer as the cladding would be advantageous. In practice, it has been found that if such a material is used for the cladding, then unacceptable microbending losses are induced in the waveguide. Soft polymeric and specifically silicone rubbers when used as the waveguide cladding are advantageous in that they help to cushion the waveguide from induced microbending losses.
Another prior art approach to terminating silicone clad waveguides has been to remove an end portion of the cladding and form an adhesive bond between the exterior cylindrical surface of the core and the bore of a connector or other waveguide supporting structure. If an adhesive is used which does not have a lower refractive index than the core, then a high loss termination is produced.
The minimum low refractive index cladding thickness is at least 3 and preferably at least 12 times the wavelength of the light to be propagated. If this minimum thickness criteria is not met, then undesirable light loss from the core will also result. Therefore, even if an adhesive with a sufficiently low refractive index is used, it is still important that the core be spaced sufficiently apart from the waveguide support structure to avoid light losses.
Prior art efforts to terminate silicone clad waveguides have also included dipping an end of a glass core with no cladding into a solution of a dissolved, heat fusible polymer having a refractive index lower than the refractive index of the exterior surface of the glass core. The core is slowly withdrawn from the solution and warmed with hot air thereby causing the solvent to evaporate and the polymer to fuse into a thin layer. In theory, this procedure can be repeated as many times as necessary to build up as thick a polymer layer as is desired. In practice, the polymer residue left on the surface of the core after the cladding has been stripped off is difficult to remove entirely and is difficult to bond to. As a result of these difficulties, the polymer layer formed by dip coating is frequently not entirely bonded to the glass and not uniformly distributed around the core. Not only is this procedure time consuming and craft sensitive, but also, it does not provide a practical solution to the problem of centering and bonding a small diameter core within a bore of an inexpensive waveguide connector. This technique is more fully described in the article by R. L. Warkentine, entitled "To Terminate Plastic Clad Silica Fibers, First Strip and Reclad the Ends", Electronic Design, Oct. 25, 1978, Pages 118 and 119.

Fiber optic waveguide termination and method of forming same


A sealing system is associated with an engine having two engine parts to be sealed, and includes a gasket situated between the engine parts. The engine parts include at least one annular groove around a hole to be sealed, and the gasket includes a bead extending outwardly from the gasket around the hole. The size o the bead is greater than that of the annular groove. When the gasket is tightened between the engine parts, the bead is compressed inside the groove and deforms to securely seal between the gasket and the engine parts. As a result, even if the engine part is slightly moved, the gasket can securely seal between the engine parts.

The present invention relates to a sealing system using a metal gasket with a bead projecting outwardly from the gasket for sealing between two engine parts.
In a metal gasket, it is common to form a bead on a metal plate around a hole to be sealed. When the gasket with the bead is tightened between the two engine parts, the bead is compressed by the engine parts, so that the bead is flattened and generally forms a plurality of corrugated beads to tightly seal around the hole to be sealed.
In a steel laminate gasket formed of a plurality of metal plates, although a bead may be formed on an outer plate to extend outwardly from the gasket, since the strong sealing pressure is generally formed on the compressed or corrugated beads, if the corrugated beads directly abut against an engine part, the engine part may be deformed or partly dented by the corrugated beads. Also, a sealing portion, i.e. top portions of the corrugated beads abutting against the engine part, is narrow.
Therefore, in case the bead is formed on the outer plate of the steel laminate gasket, the bead is formed to orient toward another plate of the gasket. Namely, the bead does not directly abut against the engine part.
In case the bead is formed on a middle plate between the two outer plates, when the bead is compressed, the bead is flattened and pushes the outer plate against the engine part. As a result, a relatively large sealing portion is formed by the bead, which orients toward the engine part.
As explained above, in case the bead is formed on the middle plate, relatively large sealing pressure is formed between the gasket and the engine parts. Therefore, the bead is generally formed in the middle plate around a hole to be sealed.
In a diesel engine, very high pressure is formed inside a cylinder bore when actuated, such as 120-140 kg/cm.sup.2. Lately, the combustion pressure is going to increase further. Consequently, although a cylinder head is tightly attached to a cylinder block by bolts, the cylinder head moves or vibrates in the directions toward and away from the cylinder block.
In case the pressure of 120 kg/cm.sup.2 is formed inside the cylinder bore, the cylinder head moves about 4 micro meters in a vertical direction. In case the pressure of 140 kg/cm.sup.2 is formed, the cylinder head moves about 5 micro meters.
In the diesel engine, although a steel laminate gasket with beads is installed between the cylinder head and the cylinder block, the gasket may not absorb such movement of the cylinder head. Especially, as the sealing ability decreases in a long usage, leakage may occur between the cylinder head and the cylinder block.
Namely, in a conventional gasket, a bead formed on a plate of a gasket is substantially completely flattened when compressed, so that elasticity of the bead is not sufficiently utilized. Therefore, it is difficult to completely seal between the engine parts which vibrate severely.
Accordingly, one object of the present invention is to provide a sealing system with a metal gasket, which can seal tightly even when high pressure is formed between two engine parts.
Another object of the present invention is to provide a sealing system as stated above, which can seal securely even when an engine part is slightly moved.
A further object of the present invention is to provide a sealing system as stated above, which is made simply and can be manufactured economically.
A still further object of the present invention is to provide the metal gasket, which can securely seal between the two engine parts.
Further objects and advantages of the invention will be apparent from the following description of the invention.

Sealing system using metal gasket with projection bead


A digital surround sound decoder. The decoder uses an architecture including two signal processing chips to achieve a program that can decode audio data at sufficiently high resolution. The decoder performs in real time and is compatible with standard surround sound formats. The decoder includes software that utilizes table lookups for critical functions in the decoding process. The processing flow of the decoder's program takes advantage of the multi-function capability within the specific processors used in the design while using a minimum number of program instructions. The program implements band pass filtering, sum-difference calculations, fast-attack slow-decay integration, summation and reciprocal processing, determination of fast and slow modes, look-up table indexing, adaptive matrix processing and various other functions to generate decoded surround sound signals from encoded left and right signal inputs.

"Surround sound" is a term used in audio engineering to refer to sound reproduction systems that use multiple channels and speakers to provide a listener with simulate placement of sound sources. Typically, the listener is positioned between multiple speakers. By playing a sound at different intensities through one or more of the speakers, the sound is positioned with respect to the listener. In this way the listener may be "surrounded" with sound sources to create a more interesting or realistic listening experience. The device that plays back recorded audio signals through the speakers to achieve the surround sound effect is called a surround sound decoder.
Surround sound decoders are a common device in commercial movie theaters since surround sound is especially well-suited as a movie audio effect. By using surround sound along with a theater's large projection screen, an audience can be more completely immersed in the movie experience. Speakers toward the from of the theater, sometimes behind the screen itself, can localize sound to the right, left or center of the screen so that, for example, a movie character's voice can appear to come from the approximate position of the character on the screen. Additional speakers to the sides of the theater can be used to create sounds that are intended to be at the extreme sides of the screen or off-screen. Other popular locations for surround sound speakers are at the back and ceiling of the theater.
Surround sound decoders are also becoming more common in the consumer retail market. With the growing popularity of home entertainment centers, many consumers are creating high quality theater-like image and audio centers within their homes. Surround sound audio capability is one of the advanced features installed in such entertainment centers.
As a result of the success of surround sound in the theater and home markets the need for accurate, efficient and cost effective surround sound devices is increasing. Further, the audio processing technology in both theater and home systems has become increasingly digital. This places a burden on the surround sound decoder to meet the high quality specifications of digital audio processing such as low noise and wide dynamic range. However, typical surround sound decoders use analog components which fail to achieve the fidelity of today's digital audio. Also, the use of analog components in surround sound decoders causes the decoders to be sensitive to thermal effects and to decode inaccurately in some cases. The attempts to produce analog circuits that compensate for analog deficiencies require using high precision components, or adding additional circuitry to the decoder design, resulting in a more expensive decoder.
FIG. 1A shows an arrangement of speakers in a typical 4 channel surround sound system 100. Speakers 102, 104 and 106 play left ("L"), center ("C") and right ("R") channels, respectively. Speakers 108 and 112 are two speakers used to play the surround channel ("S"). Listening area 110 is positioned approximately in the middle of the speakers. In a cinema application, the movie screen (not shown) would be adjacent to, and parallel with, the left, center and right speakers.
The speakers are driven by channel signals generated by decoder 114. Decoder 114 derives the channel signals from a sound source signal generated by sound source 116. Sound source 116 may be a movie projector, compact disk ("CD"), laser disk, video tape, etc. A common format provides for the sound source to output two signals as left and right stereo signals to decoder 114. The decoder operates according to a surround sound format that specifies how the four L, R, C and S signals are encoded onto, and decoded from, the two stereo signals. One such format is promulgated by Dolby Laboratories and known as Dolby Pro Logic Surround. For a description of this surround sound format, and associated analog decoder, refer to papers published by Dolby Laboratories such as "Dolby Pro Logic Surround Decoder Principles of Operation," by Roger Dressier; 1988, 1993, reference no. S93/8624/9827.
FIG. 1B is a block diagram of a prior art analog surround sound decoder 120 such as that described in the reference above. Stereo inputs L.sub.in and R.sub.in at 122 are provided to the decoder from a signal source. According to the surround sound format, the stereo signals not only contain the standard left and right stereo signals, but are encoded with center and surround signal information. The center signal is encoded onto the SL and SR signals by dividing the center signal equally among L.sub.in and R.sub.in. In other words, the center signal is attenuated by 3 dB and added to each of the L.sub.in and R.sub.in signals. In contrast, the surround signal is phase encoded onto the stereo signals after first being band limited from 100 Hz to 7 kHz and processed with noise reduction encoding. The left stereo signal is added with the surround signal phase shifted by plus 90 degrees while the right stereo signal is added with the surround signal phase shifted by minus 90 degrees.
This encoding format provides for complete separation between the left and right signals. The surround signal is recovered by taking the difference between the left and right stereo signals. The center signal is recovered by adding the left and right stereo signals, thus cancelling the surround components which are 180 degrees out of phase.
Returning to FIG. 1B, the stereo signals L.sub.in and R.sub.in are decoded by passing the signals through bandpass filters 124 to remove strong low-frequency and high-frequency signals that may interfere with the decoding. Signals L and R are derived, as a result. A circuit at 126 sums L and R to generate the center signal, C. Circuit 128 subtracts L and R to generate the surround signal, R. Full wave rectifier circuits 130-136 are used to generate a direct current ("dc") voltage for each of the respective signals SL, SR, center and surround. These dc voltages are used to compute a log difference for each of the pairs SL/SR and center/surround by log-difference amplifier circuits 138 and 140.
The outputs of log-difference amplifier circuits 138 and 140 are dual polarity signals. The SL/SR dual polarity signal indicates that the left channel is dominant if the signal is, for example, positive. When the signal is negative it indicates that the right channel is dominant. The detection of a dominant signal is important to surround sound processing because of a human listener's tendency to focus on a single dominant sound. For this reason, the placement of sounds in the surround sound decoding and playback is heavily dependent on a dominant sound in the sound track. If a dominant sound is to come from the left, the quality and intensity of the right, center and surround channel outputs may be sacrificed to provide for a clear left originating sound.
Similar to the SL/SR dual polarity signal, the full wave rectifier circuits 134 and 136 and the log-difference amplifier circuit 140 output a center/surround dual polarity signal that indicates, in one polarity, that the center channel dominates and, in the other polarity, that the surround channel dominates.
The amplitudes of both of the SL/SR and center/surround dual polarity signals indicate to what degree the dominant signal of the pair dominates. A feature of the surround sound circuit is that it operates differently depending on the relative dominance of signals. If the dominance of a dual polarity signal exceeds a threshold level then the surround sound circuit switches from a slow mode to a fast mode of operation. This switching is performed in the dual time constant circuits 144 and 146 under the control of threshold switch circuit 142. The dual time constant circuits
Polarity splitter circuits 148 and 150 resolve the dual polarity dominance signals into four dominance control signals, or voltages, E.sub.L, E.sub.R, E.sub.C and E.sub.S. These control voltages are used to control eight voltage controlled amplifiers ("VCAs") 152, to amplify or attenuate the SL and SR signals. Thus, VCAs 152 output eight sub-term signals corresponding to SL and SR amplified according to each of the four control voltages.
The eight sub-term signals, along with the original SL and SR signals, are provided as inputs to combining network 154. Combining network 154 derives the left, right, center and surround signals from SL and SR and adjusts the strength of each of the signals according to the 8 sub-term signals. The surround signal is passed through filter 156, time delay 158, low pass filter 160 and noise reduction circuitry 162 before being output as the S channel signal. The left, right, center and surround signals may be subjected to balance, gain or other adjustments before being output as the L, R, C and S channel signals.
Although the analog surround sound decoder circuit of FIGS. 1A and 1B is adequate to perform surround sound decoding, the circuit requires the use of matched and calibrated analog components to perform sensitive functions such as the decoding of SL+SR and SL-SR signals. Also, because of the dual and quad nature of signal paths whose relative outputs play a large role in determining the circuit's operation any differences in the functional parameters of components in the paths could cause errors in the decoding. The circuit is also susceptible to all of the shortcomings of analog circuitry used in audio applications such as the introduction of noise, different characteristics of the circuit due to environmental (especially thermal) effects, non-uniform frequency response, etc.
Thus, it is desirable to produce a digital surround sound decoder. However, the successful design of a digital surround sound decoder is difficult since the accuracy and speed needed to process an audio signal at high resolution requires a high data throughput and a large number of instructions per second in the digital signal processing ("DSP") program. Further, to be useful the digital surround sound decoder must be compatible with existing surround sound formats.


Systems, devices, and methods for locating buried conductors using ambient electromagnetic signals, such as AM or other broadcast signals, are described. A buried utility locator may include a plurality of spatially separated antenna arrays, a receiver circuit coupled thereto, and a processing element programmed to process measurements of ambient electromagnetic signals and associated electromagnetic signals radiated from current induced in the buried conductor from the ambient signals to determine information about the buried conductor.

Utility locators (also denoted as "buried object locators", "utility locators", "buried utility locators", or "locators") are devices for sensing magnetic fields emitted from hidden or buried utilities (e.g., underground utilities such as pipes, conduits, or cables) or other conductors, and processing the received signals to determine information about the conductors and the associated underground environment. Traditional utility locators and associated systems used in locate operations (also denoted herein as a "locate") are tuned to receive magnetic field signals generated from the utility or other conductor through currents flowing in the utility. These currents may be coupled, either directly, inductively, or capacitively, from a signal transmitter device (also denoted herein as "transmitter") specifically designed for such tasks or may be currents intended to flow in the conductor, such as power grid currents for providing power to homes or businesses.
In some locate operations, such as with blind pipeline surveys, it may be difficult and/or impractical to position a transmitter to effectively couple signals to a conductive buried utility line using a typical transmitter. Though the use of a transmitter may, in some cases, be used to locate certain utilities, the reliance upon a transmitter in a utility locating operation may not effectively inform the user of the absence of utilities within the ground where the transmitter has failed to couple signal onto the utility. Furthermore, locator devices and systems as known in the art fail to take advantage of other signal information which may be passively available within the locate environment beyond those signals intentionally generated by a transmitter. Existing utility locators and associated systems that utilize passive signals for the purpose of locating buried utility lines are greatly limited in number and selection of tunable passive frequencies, typically only using 50 Hz or 60 Hz powerline frequencies or associated harmonics.
Accordingly, there is a need in the art to address the above-described as well as other problems.

Utility locating systems, devices, and methods using radio broadcast signals