Method and apparatus are provided for encoding data types to identify the type of object being operated on during execution of a computer program on a data processing system including byte-addressed memory. The object is represented by at least one machine word having a plurality of bits. The method includes the steps of storing an object in the byte-addressed memory so that the lower three bits of the object are in a zero state and setting one of the lower three bits to a non-zero state to indicate a particular data type. Three different types of data can be verified by checking the state of a single bit. In one embodiment of the invention the method further includes the step of setting a second one of the lower three bits to a non-zero state to indicate that the object, such as NIL, is a member of two data types. In a second embodiment of the invention the method further includes the step of setting a bit immediately adjacent the lower three bits to a non-zero state to indicate whether the object is a short-float object. The invention has particular utility for use with the computer programs written in a LISP-like language.

A Common LISP system, unlike strongly-typed languages such as Pascal, uses latent data typing. Latent typing allows a function to delay the determination of the "type" of an argument during run-time. Type identification is important because although some functions can operate on multiple data types, others operate only on specific data types. The program must be able to identify types and invoke appropriate functions.
Functions that operate on pointers to LISP objects, however, do not need to know the objects' data type. Only when the value of the LISP object is operated on is its data type required. This characteristic allows the LISP program to manipulate "unknown-type" objects, and serves to support the use of future objects in LISP as disclosed by reported by Robert H. Halstead, Jr., of the Massachusetts Institute of Technology, in his article entitled "Multilisp: A Language for Concurrent Computation", which appeared in the October, 1985 issue of ACM Transactions on Programming Languages and Systems, Vol. 7, No. 4.
Most functions, nevertheless, do operate on their arguments and therefore need to know to which data type the arguments belong. It is well known that this data type checking requirement can consume significant computational resources. This is one reason why machines that execute LISP code, which perform these type checks as part of their normal instruction cycle, have a performance edge over "stock" hardware. This is also why compiler declarations for eliminating run-time data type checking can result in significant increases in performance.
Data type checking of the prior art includes the Object Direct, Pointer Indirect, Tagged and Pointer Direct schemes. The Object Direct scheme encodes the type with the object. Its disadvantages stem from the extra space required in each object to hold the data type information, in addition to the necessary memory reference when only a pointer to the object is available.
While the Pointer Indirect method reduces the storage overhead of the Object Direct method by dividing the available memory into regions for each data type, uneven storage can occur, resulting in large "holes" of memory that are unused.
The Tagged scheme is inherently undesirable because of the specialized hardware requirements that follow from encoding the type in the pointer, but separate from the address.
The Pointer Direct scheme encodes the type directly in the pointer. The need to access memory is eliminated, driving performance up, and special hardware is not required.
Within the Pointer Direct scheme, there are several methods in the prior art of encoding the type in the pointer. An important consideration in type encoding is the handling of immediate objects. These objects are known to include small integers or "fixnums," small floats and characters. By representing these objects in the pointer itself, memory does not have to be allocated for them. The non-type bits of the pointer contain the immediate object. If an operation involving immediate objects could result in an overflow, the data must be shifted in the high bits to allow for detection. If no overflow is possible, the shifts are unnecessary.
When immediate objects are not involved, Shifted, High-bits Encoding can be used. In this method, the high address bits of the 32 bit word are used to divide the memory into regions, each associated with only one data type. Thus, each data type has its own contiguous block of memory. To retrieve the type from the pointer, the lower address type bits must be compared to a given type code. This is accomplished by either masking out the lower bits and comparing or shifting the pointer and comparing. Care must be taken when shifting or masking to insure valuable information (i.e. the operand) is not destroyed during the operation.
The main disadvantage with this method reveals itself when the programmer is determining how many bits to allocate for type representation. The number selected determines how many types can be distinguished, in addition to determining the size of that type's associated region. This relationship can be seen in FIG. 1. An allocation of 5 bits out of a 32-bit address yields typing support for 32 different data types, which is usually adequate. The resulting memory, roughly 131 megabytes, should also be sufficient for most Common LISP applications. If, however, a full 32-bit address is not supported, a severe shrinkage in the region size results. A 24-bit address with 5 type bits yields only a one-half megabyte space, leading to frequent garbage collections and an inability to support the larger applications. Further, while reducing the number of type bits is a consideration, it is not acceptable. This is because while a reduction in type bits to 4 would yield roughly 16 megabytes of memory space, it would also reduce the number of types available to 16. This would result in some objects sharing the same pointer type, forcing a supplemental method of type representation.
An additional disadvantage of the Shifted, High-bits encoding method is the sparsely populated virtual address space that frequently results. This is because storage allocated for one type may be unused while other types run out of storage space.
An alternative to using the high bits to encode is to use the Low-bits Encoding method. While this method has a number of known advantages, there are disadvantages. In addition to shifting or masking problems of high-bits encoding, there are not enough low bits available for encoding. This problem is shown in FIG. 2. In a byte-addressed machine with a 32 bit word size, a one-word-aligned address leaves bit 0 and bit 1, the two lower bits, as zeros. Because these are not used for addressing, they can be used for type encoding. A two-word alignment can also be used, but this only frees a third bit for type encoding, allowing 8 types.
An additional complication occurs when the pointer address is not aligned properly after shifting or masking. Resultant memory accesses are slowed with unaligned addresses, since additional bus cycles are required to align the addresses by adding a displacement to the pointer.
Another variation of low-bit encoding is called Shifted-Address, Low-bits Encoding. In this method, the full lower byte is used to encode, allowing 256 types to be encoded. The low byte must be shifted out before the pointer is used to reference memory to get the object. A common compare-byte instruction can be used to the test low byte. The major problem with this scheme is that the pointer must always be shifted before a memory reference, even when type checking is not being performed.
Another problem with this scheme is that the address space is limited to 24 bits when using a 32 bit address. While one-word and two-word alignment can add two to three bits respectively (see FIG. 2), the same alignment complications associated with Low-bits Encoding exist.
The last method of the prior art used for type encoding is called Pointer-direct, Bit-assignment Encoding, and can be used for high-bit or low-bit encoding. Instead of using a bit pattern to encode a data type, individual bits are assigned in the pointer to represent a certain data type. In this method, only a bit test needs to be performed. The disadvantage with this method is that there is only a limited number of bits available for assignment. For example, if bit-assignment encoding using 5 type bits, only 6 types can be represented, as shown in FIG. 3. Using these same 5 bits in the shifted, high-bit scheme yielded 32 types.
Similarly, in the low-bits case, if bit-assignment encoding using 3 type bits, only 4 types can be encoded. Using these same 3 bits in non-bit-assignment low-bits encoding yielded 8 types.
A hybrid of the aforementioned strategies was proposed by the authors of COINS Technical Report No. 88-35, dated Sept. 15, 1988 and entitled "Common Lisp Object Representation Strategies: The Umass Parallel Common Lisp Implementation". The inventor of the present application was a co-author of the report. A combination of the Object Direct and Pointer Direct strategies discussed above is used. By using two-word alignment, the lowest 3 bits are available for encoding. Specific types are assigned to these lower 3 bits, and the assignments are shown in FIG. 4. If, however, these three bits are all zeros, then 5 additional bits, bit 3 through bit 7, are encoded to contain the type of the object. These bit encodings are displayed in FIG. 5. Each of the types represented are briefly discussed below, followed by the disadvantages of the scheme.
If all three lower bits are zeros, then the full lower byte contains the type of object. For these, a simple compare-byte instruction is used. Characters have bit 6 set, and the second byte contains the code. "Fixnums" do not have bit 6, the immediate bit, set as do all other immediate objects. Because of the desire to provide for quick checking and operation on fixnums, fixnums are represented by having the entire lower byte all zeros. This allows for fixnums to be operated on directly without any shifting, masking or correction.
All of the non-immediate types are encoded in the low-byte with bit 3 set. Thus, the comparing done for type checking using the EQL test (the default test function for many Common LISP functions) is done with no memory reference. The pointers to these non-immediate numbers do, nonetheless, have to be shifted before accessing their values. In addition, the address space available to them is reduced to only 27 bits (shift 5, leaving the 3 high type bits as the lowest address bits). These drawbacks are minimized by the fact that these numbers were not intended to be "high-performance" numbers, nor are they heavily used. Time spent manipulating their values surpasses the extra instruction to shift the pointer.
The hybrid scheme also supports futures, and supports them as first class objects. This effects the EQ test, another frequently used LISP test. In LISP, two objects are EQ if either they are identical pointers, 0R if either or both of them is a future object which has a determined value that is "EQ" to the other object. As a result, all EQ tests must check for futures before failing. And because the future type is encoded directly in the pointer (bit 7), no memory reference is required. This however, has the same drawbacks as the non-immediate types: the pointer must be shifted before accessing the future object. Because the large majority of time the objects will not be futures, the tradeoff is acceptable.
The object direct portion of the scheme utilizes bit 2, as shown in FIG. 4. When set, the object begins with a header word, with the low byte in the header containing the type. Testing for these types requires a memory reference. Possible types include arrays, structures, compiled functions and any number of user-defined types.
Testing for either a Symbol or List (Cons) is a simple bit test. The key is setting the appropriate bit. For a Symbol, seven is subtracted from the two-word-aligned pointer. Referring back to FIG. 2, one can see this has the effect of setting bit 0. For a List, six is subtracted from the two-word-aligned pointer. Again, referring back to FIG. 2, it can be seen this shift has the effect of setting bit 1. To access the Symbol, similar positive displacements are made to align the pointers to word boundaries.
There are, however, two main disadvantages with this scheme. The first main disadvantage deals with the representation of NIL. In a LISP system, NIL can be operated on as a Symbol or a List. As a result, bit 0 and bit 1 in FIG. 4 should both be set for NIL. The problem comes when accessing the memory location. For a Symbol operation, seven should be added to the pointer. This addition leaves the lower 3 bits equal to 010. For the far more common List operation, six should be added to the pointer. This addition leaves the lower 3 bits equal to 001. Because the system is two-word-aligned, and the lower two bits are not 00, both of these results are not word-aligned. Either subsequent access will be exceedingly lengthy because the access is across a word boundary.
In other words, in a binary system, bit 0 and bit 1 represent "1" and "2" respectively, and bit 3 represents "4". In a word-aligned system, addresses occur every four bytes. Subsequently, word boundaries occur every four bytes, i.e. 0, 4, 8, etc. When the lower two bit are not all zeros, and a memory access occurs, a word boundary must be crossed. And when word boundaries are crossed, memory accesses are costly from a performance standpoint. The other disadvantage deals with the representation and subsequent use of a certain type of immediate object: a short-float. Because the entire lower byte is used for type encoding, short-floats have only 24 bits of value. This results in rather low precision. In addition, a mechanism has to be utilized which converts the 24-bit short-float into a representation which is recognizable by the hardware. This conversion is quite costly from a performance standpoint.

Method and apparatus for encoding data types for object identification


A video processing apparatus including a memory to store a plurality of character strings corresponding a plurality of channels in predetermined sequence, a display part to display the character string to be superposed on a picture of the corresponding channel, a signal receiver to receive a forward or backward change signal for the character string in accordance with selection of a user, and a channel selection controller to control the display part to display a character string previously or next to the character string of the channel being currently displayed such that the previous or next character string is superposed on the picture of the corresponding channel, when the signal receiver receives the forward or backward change signal for the character string. Thus, a user can easily and quickly select a desired channel from among a plurality of channels. Also, a user can select a desired channel through simple, convenient and small user interface.

1. Field of the Invention
The present invention relates to a video processing apparatus, and more particularly, to a video processing apparatus, which allows a user to easily and quickly select a desired channel among a plurality of channels.
2. Description of the Related Art
Recently, a video processing apparatus such as a television (TV) has been widely used to receive a broadcasting signal for digital TV broadcasting, cable TV broadcasting or the like, and process the received broadcasting signal to thereby output pictures and sounds.
Such a broadcasting system including the digital TV broadcasting, the cable TV broadcasting or the like provides a user with hundreds of channels. However, it is difficult for a user to select a desired channel from among hundreds of channels by referring to only a channel number.
Accordingly, there has been proposed a video processing apparatus for the digital TV broadcasting, which can receive an electric program guide (EPG) in addition to the broadcasting signal. Here, the EPG contains channel information about a channel name, a channel genre, etc. Therefore, this video processing apparatus displays a user interface while a user watches the TV, and allows a user to select a desired channel on the basis of the channel information about the channel name, the channel genre, etc. as well as a channel number given by the EPG.
However, the user interface of the conventional video processing apparatus is complicated and inconvenient because it requires a user to do many manipulations. Further, in the conventional video processing apparatus, the user interface occupies a relatively large area of a screen, thereby interrupting the view of a user.


A mobile 3D printing device, system and method based on the addition of material intended to be attached to a lifting device with a single lifting cable or chain, including                a printing head adapted to receive material and depositing it;        fixing means adapted to link the printing head to the lifting device, and        stabilization means adapted to stabilize the position of the printing head by a gyroscopic effect.

Three-dimensional printing makes it possible to produce a real object by additive manufacturing methods, that is to say by the successive deposition of layers of material.
Initially used for the rapid prototyping of objects, 3D printing is now used to manufacture functional parts and specifically in a variety of fields such as the construction of buildings or edifices.
The benefit of 3D printing for the construction of buildings is the 30 to 60% reduction of construction waste and a shortening of the production lead times by 50 to 70% compared to a conventional method.
Currently, there are several types of technologies for the construction of buildings. Some technologies use gantry systems running on rails which support the printing head of the printer and which bracket the construction zone. These are 3D printing scalings of "small size" generally used for the printing of objects made of plastics or metals that are of "small size". The drawback with this type of technology is the bulk and the need to have a structure of large size which encompasses the building to be "printed".
To resolve this problem, another type of 3D printer for building uses a robotic arm allowing the 3D printer to be displaced at the center of the construction zone and avoid the installation of a gantry and rails.
To overcome the abovementioned limitations caused by the use of a robotic arm or a gantry running on rails, in terms of height and of action perimeter, new 3D printing systems have emerged and now make it possible to be fixed to a crane, of lattice structure type. These systems are voluminous, heavy and their installation is complex because it generally requires adapting the crane fixing system for each printing system. Furthermore, this kind of printer poses problems of stability and of energy deployed to pump the material to be deposited to the top of the crane and the printing head.
There is therefore a real need for a printing system that mitigates these defects, drawbacks and obstacles of the prior art, in particular a device that makes it possible to control the conditions of printing of the structure to be printed, in particular the position of the printing head, to reduce the labor costs and the time to install such a device on a standard crane provided with a hook.

Abstract: The printing device enables the control of the printing of a structure to be printed, in particular the position of the printing head, to reduce the labor costs and the time to install such a device on a standard crane provided with a hook.


A series of non-peptidergic antagonists of NPY have been synthesized and are comprised of cyanoguanidine derivatives of 4-phenyl-1,4-dihydropyridines of Formula (I). ##STR1## As antagonists of NPY-induced feeding behavior, these compounds are expected to act as effective anorexiant agents in promoting weight loss and treating eating disorders.

The present invention concerns heterocyclic carbon compounds comprising 4-phenyl-1,4-dihydropyridines having various aminoalkyl moieties connected via a cyanoguanidine group to the 3-position of the 4-phenyl ring. These compounds are NPY antagonists.
A substantial body of art has accumulated over the past two decades with respect to the 4-aryl-1,4-dihydropyridine class of compounds. Syntheses of compounds in this category have been driven by their pharmacologic actions involving calcium channels rendering them useful for treating cardiovascular disorders such as ischemia and hypertension.
U.S. Pat. No. 4,829,076 to Szilagyi, et al. is an example of such substituted dihydropyridine derivatives, disclosing and claiming inter alia compounds of formula (1) as calcium antagonists for treating hypertension. ##STR2##
The closest art would be our previous work involving 4-(3-substituted-phenyl)-1,4-dihydropyridine derivatives having NPY antagonist properties. These derivatives conform to structural formula ##STR3##
In (2) B is either a covalent bond or the group --NH--. The symbol Z denotes hetaryl moieties, examples being piperidine or piperazine.
In U.S. Pat. No. 5,554,621, Z is a fused ring or spiro-fused nitrogen heterocycle. In U.S. Ser. No. 482,355, Z is a piperazinyl or homopiperazinyl moiety. Z is a piperidinyl or tetrahydropyridinyl moiety in U.S. Ser. No. 639,968.
These reference compounds are easily distinguished from the compounds of the instant invention by virtue of the linking functional groups. The cyanoguanidine linking moiety is a novel structural feature in the new compounds, connecting the side-chain to the 4-phenyl ring. A cyanoguanidine moiety has previously appeared in a different location in 4-phenyl-1,4-dihydropyridine derivatives.
Alker, et al. in J. Med. Chem., 1990, 33, 585-591 disclosed, inter alia, compounds of formula (3) having calcium antagonism activity. ##STR4## As can be seen, these compounds differ structurally from the compounds of the present invention.
In summary, the prior art does not disclose nor suggest the unique combination of structural fragments which embody these novel dihydropyridine derivatives which possess good antagonist activity at NPY Y.sub.1 receptor sites while having reduced cardiovascular effects.

Dihydropyridine NPY antagonists: cyanoguanidine derivatives


The present invention describes methods for performing large-scale graph traversal calculations on parallel processor platforms. The invention describes methods for on-the-fly hypothesis rescoring that utilizes graphic processing units (GPUs) in combination with utilizing central processing units (CPUs) of computing devices. The invention is described in one embodiment as applied to the task of large vocabulary continuous speech recognition.

In recent years it has become more common for computers to have multicore and manycore processes, which significantly increases the speed at which complex computing tasks can be performed by performing such tasks in a parallel manner across the various processing cores. For some complex computing tasks however, such processors are limited by their memory capacity. For example, manycore graphic processing units (GPU) have a limit of 2-8 gigabyte (GB) of memory. This memory presents a limit for tasks such calculating a large-scale graph traversal where graph structures consist of many millions of arcs and models can be on the order of 100 s of GB in size or larger.
Therefore there is a need for methods that will effectively perform large-scale graph traversal on parallel processor platforms, by efficiently leveraging heterogeneous parallel computing cores.
One field in which such improved methods are needed is in the field of large vocabulary continuous speech recognition (LVCSR). As one example of such a need, voice user interfaces are rising as a core technology for next generation smart devices. To ensure a captivating user experience it is critical that the speech recognition engines used within these systems are robust, fast, have low latency and provides sufficient coverage over the extremely large vocabularies that the system may encounter. In order to obtain high recognition accuracy, state-of-the-art speech recognition systems for tasks such as broadcast news transcription[1, 2] or voice search [3, 4] may perform recognition with large vocabularies (>1 million words), large acoustic models (millions of model parameters), and extremely large language models (billions of n-gram entries). While these models can be applied in offline speech recognition tasks, they are impractical for real-time speech recognition due to the large computational cost required during decoding.
The use of statically compiled Weighted Finite State Transducer (WFST) networks, where WFSTs representing the Hidden Markov Model (HMM) acoustic model H, context model C, pronunciation lexicon L, and language model G composed as one single network, commonly known as an H-level WFST, makes it possible to perform speech recognition very efficiently [5]. However, the composition and optimization of such search networks becomes infeasible when large models are used.
On-the-fly composition is a practical alternative to performing speech recognition with a single fully composed WFST. On-the-fly composition involves applying groups of two or more sub-WFSTs in sequence, composing them as required during decoding. One common approach is to precompose HoCoL before decoding and then compose this with the grammar network G on-the-fly. On-the fly composition has been shown to be economical in terms of memory, but decoding is significantly slower than a statically compiled WFST [6].
An alternative approach for efficient WFST decoding is to perform hypothesis rescoring [3] rather than composition during search. In this approach Viterbi search is performed using HoCoGuni, and another WFST network Guni/tri is used solely for rescoring hypotheses generated from the Viterbi search process in an on-the-fly fashion. Since this algorithm allows all knowledge sources to be available from the beginning of the search this is effective for both selecting correct paths and pruning hypotheses.
With manycore graphic processing units (GPU) now a commodity resource, hybrid GPU/CPU computational architectures are a practical solution for many computing tasks. By leveraging the most appropriate architecture for each computational sub-task, significantly higher throughput can be achieved than by using either platform alone. Prior works [7, 8] have demonstrated the efficiency of using GPU processors for speech recognition and obtained significant improvements in throughput for limited vocabulary tasks [7]. The limited memory on these architectures, however, becomes a significant bottleneck when large acoustic and language models are applied during recognition, and also for other large-scale graph traversal computations. The most significant challenge for such computations is handling the extremely large language models used in modern broad-domain speech recognition systems [1, 2, 4]. These models can contain millions of unique vocabulary entries, billions of n-gram contexts, and can easily require 20 GB or more to store in memory. Even when significantly pruned these models cannot fit within the limited memory available on GPU platforms. To efficiently perform speech recognition with large acoustic and language models we have developed a hybrid GPU/CPU architecture which leverages large memory and local-cache of the CPU with the computational throughput of GPU architectures.

Methods for hybrid GPU/CPU data processing


Disclosed are digitally-switchable bandpass filters combining non-tunable retarder stacks with switchable liquid crystal cells. The disclosed filter embodiments function like a filter wheel with no moving parts that may provide faster switching, better image registration, compact size, and lower electrical power consumption. These benefits are attractive in portable handheld devices, such as bio-hazard sensors or glucose monitors.

A tunable filter uses electrically controlled liquid crystal (LC) elements to transmit specific wavelengths of light through the filter by exploiting the variable retardation associated with certain LC modes as a means of shifting a spectral feature. One type of LC tunable filter is a Lyot (or Lyot-hybrid) polarization interference filter. With a Lyot filter, a bandpass profile is synthesized through multistage filtering using geometric relationships between retarder stack films. The polarization analyzer of one stage forms the input polarization for a subsequent stage, such that (N+1) polarizing films are used for an N-stage filter. In other word, 2 polarizing films are used for 1 filter stage, 3 polarizing films for 2 filter stages, and so forth. The overhead associated with calibrating a fully tunable Lyot bandpass filter to provide acceptable spectral characteristics can be significant. Additionally, each polarizing film has approximately a 10% transmission loss. Consequently, tunable Lyot filters with high finesse and acceptable dynamic ranges are not only bulky and expensive, but also have poor peak transmission.
A Solc or Solc-like filter, on the other hand, can be synthesized using only two polarizers bonded to a single retarder stack. Also, the Solc filter can, in principle, be customized to reduce side-lobe levels. Presently known bandpass-tuning Solc filter approaches, however, require that each multi-order retarder stack be fully tunable. In practice, there is no significant improvement in throughput because the insertion loss of a polarizer is traded for the additional LC cell loss. Furthermore, the construction of a Solc filter is more challenging than that of a Lyot filter, in that precise alignment of many interleaved active and passive elements must be done before system calibration can commence. Consequently, if at any point an error is made in building such an assembly, a large amount of high value material may have to be scrapped.


A HVAC system includes a housing including at least one wall, an air flow path defined at least partially by the at least one wall, and a door disposed in the air flow path, where the door is configured to i) block a flow of air through the air flow path when the door is in at least one closed position, and ii) allow the flow of air through the air flow path when the door is in a position other than the at least one closed position. A gap is formed between the door and the at least one wall when the door is in the position other than the at least one closed position. The HVAC system further includes a noise-reducing feature defined on at least a portion of the at least one wall. The noise-reducing feature configured to break up, into several smaller structures, an air flow structure formed when air flowing through the gap contacts an end of the door, thereby reducing air vibration in the gap and reducing noise of the HVAC system during operation thereof.

The present disclosure relates generally to HVAC systems and, more particularly, to an HVAC system including a noise-reducing feature.
HVAC systems are often used for climate control of, e.g., internal cabin areas of an automobile. HVAC systems are typically configured with an HVAC unit having at least one heat exchanger disposed in a housing and, in some instances, an HVAC distribution system operatively connected to the HVAC unit. The HVAC system further includes one or more air flow paths for allowing air to flow, for example, to, from, and/or within the HVAC unit and the HVAC distribution system. Additionally, the HVAC system includes one or more doors operatively associated with the air flow path for controlling the amount of air flowing to, through, and/or from the HVAC unit and/or the HVAC distribution system. In instances where one of the doors is in a partially open position, substantially laminar high speed flow of the air travels through a gap formed in the air flow path between the door and the housing wall. In some instances, this high speed laminar air flow generates undesirable noises (e.g., whistles or hisses) in the HVAC.


An embodiment provides a method for transferring information utilizing a serial communication command structure over an unreliable or a non-continuous communication channel, including: establishing a serial command structure, wherein the establishing comprises defining a package structure having a predefined format, wherein the serial command structure comprises bounded data; and transmitting, over the unreliable or the non-continuous communication channel, data from a sending entity to a receiving entity utilizing the serial command structure and in the predefined format. Other aspects are described and claimed.

Transmitting information between entities is important. The ability to transmit the information utilizing a wireless connection allows for more flexibility regarding the entities that can communicate and the location of the entities with respect to each other. In other words, wireless transmissions allow for communication between entities that may not always communicate with each other or entities that need to communicate with multiple entities. For example, wireless transmissions allow for communication between an instrument and a mobile device, where the mobile device can communicate with many instruments. By utilizing wireless communication, the mobile device does not have to be physically wired into each instrument to receive information from the instrument. Different wireless communication techniques have different proximity requirements between the sending and receiving entities. For example, some wireless communication techniques may require entities to be in close proximity to each other, whereas other wireless communication techniques allow for a greater distance between the entities. Additionally, different wireless communication techniques have different reliability and security levels and also different power and processing requirements than other wireless communication techniques. Thus, the wireless communication technique that is chosen for a particular application is critical to ensuring the success of the transmission of information within the application.

Serial command protocol encapsulating wire transfer protocol


A disk-error detection system may include a storage array having a plurality of storage disks configured to store data. The disk-error detection system may include a processor in communication with the storage disks. The processor may detect presence of a media error in a storage disk from the plurality of storage disks during a read operation of the data stored on the storage disk. The processor may perform a media-error detection scan of a predetermined portion of the storage disk in response to the detection of the media error. The location on the storage disk of the predetermined portion of the storage disk may be based on location of the media error on the storage disk. A method and computer-readable medium may also implement disk-error detection.

1. Technical Field
The present disclosure relates generally to media error detection, and in particular, to detection of media errors in disks proximate to previously found media errors.
2. Related Art
Latent sector errors (LSEs) that occur on hard disk drives (HDDs) within a redundant array of independent disk (RAID) subsystem are typically recoverable when the RAID group is otherwise healthy. However, if RAID redundancy is already compromised (due to disk failure, as an example), the detection of an LSE on the redundant drive typically means data-loss has occurred.
Traditional RAID subsystems attempt to mitigate the probability of hitting this condition via background data scrub operations designed to find and repair LSEs prior to occurrence of data loss following a disk failure. However, if an LSE is found in response to a host input/output (I/O), most RAID subsystems repair the single specific LSE encountered (using RAID) and complete the associated I/O to the host, but do nothing to expedite the discovery and repair of LSEs that likely lie in wait within the logically adjacent address ranges. If a disk failure occurs prior to the background data scrub operation gets to the affected area of disk, data loss will have occurred.

Disk-media-error detection and correction


A method of making a silicided inverse T-gate with an L-shaped silicon spacer and nitride sidewall spacers is described. The L-shaped spacer is electrically connected to the gate.

Essential components of field effect transistors include a gate structure and source and drain regions on opposite sides of the gate structure. As is well known, the voltage applied to the gate structure controls the current flow between the source and drain regions which are doped and formed by, e.g., ion implantation. In metal oxide field effect transistors (MOSFET), the gate is separated from the current channel by a thin oxide layer.
As device dimensions shrank from those used in the early MOSFET devices, effects that were unimportant with the early devices became important and the basic structure described had to be modified to obtain the desired device characteristics. For example, the conventional MOSFET structure has a relatively large electric field near the portion of the gate closest to the source/drain regions. The electric field attracts carriers from the channel and some carriers become trapped in the oxide. Such trapped carriers may lead to, e.g., undesirably large changes in the threshold voltage. As the device dimensions scale down to submicron dimensions, these effects are enhanced. Dividing the source/drain regions into two regions with different dopant concentrations reduces the scope of some of these effects. The region with the lower dopant concentration is nearer the gate structure than is the region with the higher dopant concentration. The structure is called a lightly doped drain and is commonly referred to by the acronym LDD.
The now conventional LDD structure is typically formed with two ion implantation steps; a light, first implant and a heavy, second implant which does not penetrate into the lightly doped regions because of, e.g., oxide sidewalls on the gate structure that are formed after the first implant step. This structure alleviates the effect discussed above with respect to the earlier MOSFET structure which lacked an LDD structure.
However, for channel lengths of approximately 0.6 microns and less, the conventional LDD structure described also begins to exhibit drawbacks. For example, the oxide spacers begin to suffer adverse effects from hot carriers and the S/D resistance, due to the lightly doped region, becomes significant as compared to the channel resistance for channel lengths less than 0.6 .mu.m. Several structures have been proposed to overcome at least some of the drawbacks of the conventional structure by using a gate structure that overlaps at least a portion of the heavily doped source/drain regions, i.e., there is a gate/drain overlap. See, e.g., Izawa et al., International Electron Devices Meeting, pp. 38-41, Washington, D.C., 1987. The device described was termed GOLD which is an acronym for gate-drain overlapped LDD. The structure is formed by using an etching process that leaves a portion of the gate polysilicon overlapping the LDD regions. Another approach to achieving gate/drain overlap is described by Chen et al. in 1990 Symposium on VLSI Technology, pp. 39-40. This approach used polysilicon sidewalls on the gate structure which overlapped the source/drain regions. The authors stated that the use of conducting sidewalls instead of insulating sidewalls was a straightforward method of obtaining the desired gate/drain overlap, but the Si sidewalls were not connected to the transistor gate. That is, the sidewalls are floating electrically and only capacitively coupled to the gate. The structure does not take full advantage of the gate/drain overlap.
Another approach to gate/drain overlap which has received much attention recently is termed the inverse T-gate. See, for example, the papers by Wen et al., pp. 765-768 and Pfiester et al., pp. 769-772, International Electron Devices Meeting, Washington, D.C., 1989. The inverse T-gate structure realizes the gate/drain overlap by using a gate structure having a bottom conducting portion that is wider than the top potion and which overlaps the drain region although it is separated from the drain region by a thin oxide layer. The first paper described two embodiments. The first embodiment is exemplary and will be described briefly here. After the gate oxide is formed, an additional polysilicon layer and another oxide layer are deposited. Polysilicon for the gate is deposited and the gate patterned. These steps are followed by the deposition of another polysilicon layer and a dielectric layer. These layers are etched back to form oxide spacers which have a conductive polysilicon layer between them and the gate oxide layer. The conductive polysilicon overlaps the lightly doped drain. The second paper describes a conceptually similar structure.
None of the methods or structures described are compatible with a self-aligned silicide process, and cannot form a silicide to reduce parasitic resistance without causing a gate to source/drain bridging problem.

Transistor with inverse silicide T-gate structure


A vibratory structure includes: a first X-cut crystal substrate; a second X-cut crystal substrate stacked on the first X-cut crystal substrate so that the x-axis of the second X-cut crystal substrate is parallel to the x-axis of the first X-cut crystal substrate; a base formed by the first X-cut crystal substrate and the second X-cut crystal substrate; and vibratory arm sections formed so as to be integrated together with the base in one body, and protruding from the base.

1. Technical Field
The present invention relates to a vibratory structure made of, for example, a crystal or the like, a vibrator including this vibratory structure, an oscillator provided with this vibrator, and an electronic apparatus.
2. Related Art
Conventionally, a quartz crystal vibrator functioning as a frequency control element is adopted for an oscillation circuit provided in various electronic apparatuses.
Specifically, a tuning-fork type quartz crystal vibrator is used as a quartz crystal vibrator that is downsized, break-proof, and that accurately vibrates at a low electric power.
In the above-described tuning-fork type quartz crystal vibrator, the number of vibrations, that is the frequency, is mainly determined by the length and the width of an arm of a quartz crystal vibratory element.
Specifically, the above-described tuning-fork type vibrator for functioning as a clock source is incorporated together with an oscillation circuit into various electronic apparatuses such as a clock.
In recent years, in conjunction with the downsizing of various electronic apparatuses, a tuning-fork type vibrator of a small size has become required.
As a foregoing downsized tuning-fork type vibrator, the tuning-fork type quartz crystal vibrator including the structure which has a couple of vibratory arm sections and in which grooves are formed on the main face of each of the vibratory arm sections and drive efficiency of the quartz crystal vibratory element is improved is known.
FIG. 15 is a plan view illustrating a conventional example of a tuning-fork type vibrator.
This tuning-fork type vibrator is constituted by a crystal substrate of a Z-plate (Z-cut) in which a main face is orthogonal to the z-axis of crystal axes (xyz).
A couple of vibratory arm sections 12 and 13 are formed so as to extend from a base 11.
Here, with regard to crystal axes (xyz) in the tuning-fork type vibrator, the x-axis direction corresponds to the width (W), the y-axis direction corresponds to the length (L), and the z-axis direction corresponds to the thickness (D).
FIG. 16 is a cross-sectional view illustrating the conventional example of the tuning-fork type vibrator taken along the line C-C shown in FIG. 15.
As shown in FIG. 16, in each of the vibratory arm sections 12 and 13, grooves 12a and 13a are formed on the main faces (face perpendicular to the z-axis direction), and grooves 12b and 13b are formed on the back faces.
In addition, as shown in FIG. 16, drive electrodes are formed on the groove and a side face of each of the vibratory arm sections 12b and 13b so as to drive the vibratory arm sections 12b and 13b.
In each of the vibratory arm sections 12b and 13b, the drive electrode 14a is formed in the groove 12a and the drive electrode 14b is formed in the groove 12b. The drive electrodes 14c and 14d are formed on both side faces of the vibratory arm section 12.
The drive electrode 15a is formed in the groove 13a and the drive electrode 15b is formed in the groove 13b. The drive electrodes 15c and 15d are formed on both sides of the vibratory arm section 13.
Here, the side faces of the vibratory arm section 12 and the sides of the vibratory arm section 13 are the faces that are orthogonal to the x-axis direction.
In addition, in each of the vibratory arm sections 12b and 13b, the vibratory arm sections 12b and 13b are wire-connected to each other so that a drive-voltage with a coordinate phase is supplied to the drive electrodes 14a, 14b, 15c, and 15d, and a drive-voltage with an opposite phase related to the foregoing electrodes is supplied to the drive electrodes 14c, 14d, 15a, and 15b.
As a result, in each of the vibratory arm sections 12b and 13b, inflection vibration is generated by the electrical field generated between the main faces and the side faces in forward/backward directions, and the tuning fork is thereby vibrated.
For example, in the vibratory arm section 12, by supplying the electrical field in the x-axis direction from an inner periphery face of the groove to both side faces, when the left side portion shown in FIG. 16 is extended in the y-axis direction, the right side portion is contracted, and the vibratory arm section 12 is thereby displaced toward the vibratory arm section 13 in a direction in which the vibratory arm sections 12 and 13 face each other.
In contrast, in the vibratory arm section 13, by supplying the electrical field in the x-axis direction from both side faces to the inner periphery face of the groove, when the left side portion shown in FIG. 16 is contracted in the y-axis direction, the right side portion is extended, and the vibratory arm section 13 is thereby displaced toward the vibratory arm section 12 in a direction in which the vibratory arm sections 12 and 13 face each other.
In addition, by supplying voltage to each electrode so as to generate the electrical field in an opposite direction relative to the above-described case, the vibratory arm sections 12b and 13b vibrate in a direction in which the vibratory arm sections 12b and 13b are drawn apart from each other. Therefore, the vibratory arm sections 12b and 13b are vibrated in a retrorse horizontal direction, and the tuning fork is thereby vibrated.
As shown in FIG. 17A, normal vibration in the horizontal direction (x-axis direction) indicated by arrow B of the drawing is generated when the width W is comparatively great and the thickness D is comparatively low in the vibratory arm sections 12b and 13b.
However, if the width W is less than or equal to 1.2 times the thickness D, a vertical component that is vibration component in the direction indicated by arrow C is added in, the vibration in the direction indicated by arrow E as shown in FIG. 17B is thereby generated.
When the vibration component in the direction indicated by arrow C communicates to the base, energy (vibration energy) is lost in an adhesive or the like disposed on the fixed region of base 11 at which the vibratory element shown in FIG. 15 is fixed to a package or the like.
Therefore, the vibration by vibratory arm sections 12b and 13b may lack stability caused by variations in the fixation strength of the vibratory element.
Consequently, there is a problem in that variations in the CI (crystal impedance) values of mass-produced vibratory elements increase.
Therefore, as shown in FIG. 15, in the base 11 including a side face 11r from which the vibratory arm sections 12b and 13b are extended, and side faces 11q that makes an angle together with the side face 11r and comes in contact with the angle, the structure in which an incision 16 is formed on the side faces 11q is proposed.
In the tuning-fork type vibrator including the structure having the incision 16, it is possible to prevent the vibration of the vibratory arm section from leaking out toward the base 11.
This tuning-fork type vibrator is disclosed in, for example, Japanese Unexamined Patent Application, First Publication No. 2004-62134.
As a result, by the above-described structure, it is possible to downsize the base 11 while the CI value is maintained, downsize whole vibratory element, and reduce variations in the CI values of mass-produced vibratory elements.
In the vibratory element disclosed in Japanese Unexamined Patent Application, First Publication No. 2004-62134, the frequency is determined by the ratio between the width of the vibratory arm section and the length of the vibratory arm section (f∝W/L2).
However, in the case of attempting to further downsize the vibratory element, the width of the vibratory arm section is extremely small, and it is thereby difficult to form a groove with a stabilized shape.
Therefore, the intensity of electrical field supplied to a crystal section is variable, oscillation characteristics become unstable, and one of or all of characteristic values such as a CI value, a Q value, the capacitor ratio, or the like become degraded.

Vibrator comprising two X-cut crystal substrates with an intermediate electrode


The present disclosure provides a method of manufacturing a semiconductor structure. The method includes: receiving a substrate; forming a bit line structure on a top surface of the substrate; forming a spacer structure on the bit line structure, the spacer structure including a sacrificial layer sandwiched by a first dielectric layer and a second dielectric layer; removing the sacrificial layer to form a gap between the first dielectric layer and the second dielectric layer; reducing a width of the gap; and forming a seal layer to seal the gap.

A conventional dynamic random access memory (DRAM) cell 100, as shown in FIG. 1, consists of a transistor T and a capacitor C. The source of the transistor T is connected to a corresponding bit line BL. The drain of the transistor T is connected to a storage electrode of the capacitor C. The gate of the transistor T is connected to a corresponding word line WL. An opposite electrode of the capacitor C is biased with a constant voltage source.
However, as the DRAM cells become increasingly small, the highly compact structures of the DRAM cells result in high parasitic capacitance between a bit line and a cell plate of a trench capacitor of the DRAM cell, thereby causing parasitic leakage.
This Discussion of the Background section is provided for background information only. The statements in this Discussion of the Background are not an admission that the subject matter disclosed in this section constitutes prior art to the present disclosure, and no part of this Discussion of the Background section may be used as an admission that any part of this application, including this Discussion of the Background section, constitutes prior art to the present disclosure.

Method for manufacturing semiconductor structure


An apparatus is disclosed for applying tags with attached elastic anchor bands onto the tops of objects such as bottles in a high speed packaging application. The apparatus includes an infeed assembly for feeding a web, a conveyor assembly that receives a web and conveys it along a path in an upstream direction, a rotating selector wheel, a placement assembly, a pair of rotating jaw assembles, a vacuum cup of the selector wheel, and stretched elastic bands over the tops of respective bottles being conveyed along a path below the placing assembly. The elastic bands then snap onto the tops of their respective bottles to secure the tags to the bottles.

In the packaging industry, high speed packaging machines commonly package thousands of items such as beverage bottles in a single production run and at high speeds. It is sometimes desirable to place advertising or other indicia on the bottles in a removable manner before they are packaged. One way to do this is to place a tag containing the indicia onto the neck of each bottle where the tags are held in place with elastic anchor bands that are secured to one end of the tags. Such tags exist in the faun of long ribbons or webs wherein multitudes of tags and their elastic anchor bands are defined in the web by score lines or partial cuts so that each tag and its band can be detached from the web. A need exists for a apparatus and method for removing these tags from the web and placing their elastic anchor bands over the tops of bottles (or other objects) at high rates, in continuous succession, and in a reliable and efficient manner. There also exists a need for such an apparatus to be easily reloaded or re-threaded with a new web of tags when one web supply is exhausted to minimize the down time required to reload the apparatus. It is to the provision of such an apparatus and to the corresponding method that the present disclosure is primarily directed.

Article selection and placement assembly and method


By including plural receiving branches which are independently controllable for use in diversity reception or plural-channel simultaneous reception, a receiving device can be operated both as a diversity receiving device and as a plural-channel simultaneous receiving device.

1. Field of the Invention
The present invention relates to a receiving device including plural receiving branches.
2. Description of the Related Art
FIG. 10 is a circuit diagram of an example of a conventional receiving device. This receiving device is a diversity receiving device for OFDM (Orthogonal Frequency Division Multiplexing) signals and includes two receiving branches 10 and 20.
In the receiving branch 10, numeral 11 denotes an antenna, numeral 12 denotes a tuner which performs station selection and frequency conversion of a received signal, and numeral 13 denotes a demodulation circuit which receives an output signal of the tuner 12, performs processing such as A/D (analog/digital) conversion, orthogonal demodulation, or Fourier transform, and outputs a demodulated signal D1.
In the receiving branch 20, numeral 21 denotes an antenna, numeral 22 denotes a tuner which performs station selection and frequency conversion of a received signal, and numeral 23 denotes a demodulation circuit which receives an output signal of the tuner 22, performs processing such as A/D conversion, orthogonal demodulation, or Fourier transform, and outputs a demodulated signal D2.
Numeral 30 denotes a signal combining circuit which combines the demodulated signal D1 of the receiving branch 10 outputted by the demodulation circuit 13 and the demodulated signal D2 of the receiving branch 20 outputted by the demodulation circuit 23 by maximum ratio combining or the like and outputs a combined demodulated signal D3.
Numeral 40 denotes a decoding block which receives the combined demodulated signal D3 outputted by the signal combining circuit 30, performs processing such as demapping or deinterleave, and outputs a decoded signal D4 being an encoded data stream (for example, an MPEG stream).
Numeral 50 denotes a decoder (for example, an MPEG decoder) which receives the decoded signal D4 outputted by the decoding block 40 and performs decoding corresponding to an encoding format of the decoded signal D4. Numeral 60 denotes an output device (a monitor, a recording device, or the like) to which a decoded signal (a picture signal, an audio signal) outputted by the decoder 50 is given.
(Patent Document 1)
Japanese Patent Application Laid-open No. 2004-312333
(Patent Document 2)
Japanese Patent Application Laid-open No. 2004-112155
The conventional receiving device shown in FIG. 10 has a problem that although it can perform diversity reception, it cannot perform signal regeneration of plural channels simultaneously, and hence cannot meet multifunctionality such as multi-audio recording, multi-picture recording, or multi-screen.


An image sensor and a method of manufacturing the same that includes providing a semiconductor substrate having a photodiode, forming a color filter over the photodiode, forming a micro lens over the color filter and then forming at least one metal layer vertically extending through the microlens at an outer edge thereof.

Image sensors are semiconductor devices which convert an optical image into an electrical signal. Image sensors may be divided into change coupled device (CCD) image sensors and complementary metal oxide silicon (CMOS) image sensors (CIS).
A CMOS image sensor includes a photo diode and a MOS transistor in each of unit pixels, and thus, sequentially detects electrical signals of the respective unit pixels in a switching mode, thereby displaying an image. A CMOS image sensor is divided into photo diode regions, receive a light signal and converts the light signal into an electric signal, and transistor regions, which process the electric signal. In a CMOS image sensor, micro lenses for light concentration are formed on and/or over the upper end of the sensor. The micro lenses are made of an organic material, and are completed through processes, such as a photo etching process (PEP) and a reflow process.
However, the organic material has weak mechanical characteristics, and thus is sensitive to defects. Foreign substances are generated during a subsequent process after the formation of the micro lenses and are attached to the micro lenses, thereby causing a malfunction of the CMOS image sensor. Further, CMOS image sensor may generate image interference due to crosstalk between pixels.

Image sensor and method of manufacturing the same


An exercise device includes a frame, a press arm pivotally attached to the frame at a main pivot, a pair of press handles extending from the press arm, an adjustment link having a first portion pivotally mounted to the press arm at an adjustment pivot between the main pivot and the press handles, and having a second portion adjustably extensible and retractable from the first portion, a bracket mounted to the second portion of the adjustment link and guided by the frame for movement therealong, and a pulley mounted to the bracket and receiving a cable trained therearound from a source of resistance.

The invention relates to exercise devices with a press arm, e.g. for shoulder rotary press and other exercises, and more particularly to improved adjustment therefor.
For exercise equipment with a decline or flat to shoulder rotary pressing station, it is necessary to have a press arm whose starting position can be adjusted. It is also advantageous that no tension be put on the cabling that is linked to a source of resistance, e.g. a weight stack, during any of the starting positions, since this would necessitate a secondary adjustment with the cabling for the weight stack. In the prior art, some manufacturers have put a secondary pivot at some point between the press arm main pivot and the press handle. The pulleys and cables linked to the weight stack are attached at some point between such pivots so that the cable is never put in tension at any starting point. In such arrangement, the distance from the press handles to the main pivot of the press arm changes for each starting position, and because of this, the weight ratio is different for each starting position, which is a disadvantage. More adjustments are sometimes required to the bench and to put the user in the correct position to perform the exercise in such type of system.
In one known attempt to solve the above-noted problem, an adjustable floating link is pivotally connected to the press arm half way between the press handles and the main pivot. A pulley is attached at the bottom of the link by a cable wrapped therearound providing 1:1 resistance. When the press arm is at rest, the link stops somewhere on the frame so that when the press arm is adjusted with the adjustable link, the pulley never changes position. While the resistance profile was the same for all press positions, and the system allowed for minimal adjustments to the bench, this type of press station was not perceived well by consumers. The floating link would tend to swing back and forth when performing chest exercises, and the press station was perceived as unstable.
A known improvement to the above-noted floating pendulum adjustable link press arm adds two more links, one of them being adjustable. In this four bar linkage, two of the links remain stationary, while the press arm (being one of the links) and an adjustable link (being the fourth link) move while the starting position is adjusted. One of the stationary links is typically part of the frame, and the other stationary link is the attachment point for the cable and/or pulley. The press arm can then be adjusted without putting any tension on the cable system, and the distance from the main pivot to the press handles never changes. The disadvantage in this system is that by adding extra pivots for the linkages, more friction is introduced to the mechanism, and more cost.
The present invention accomplishes the above-noted goals without the noted added friction nor the noted added pendulum motion, and with a more cost-effective construction and mechanism. A simplified construction is provided by a frame, a press arm, and an adjustable link. The adjustable link has a pulley over which a cable passes, linking it to the source of resistance, such as a weight stack. The adjustment link is pivotally connected to the press arm between the main pivot and the press handles. The cable wraps around the pulley, which allows for a 1:1 weight resistance relationship with the cable. This is similar to the floating link system described above, except that the pulley on the present adjustable link is guided by a frame member for movement therealong, and in the preferred embodiment rolls thereon. By strategically placing the noted frame member and the coupling directional pulleys on the frame, the direction of force on the linkage causes the linkage pulley to ride on the frame member. The contact of the linkage pulley against the frame stops the adjustable link from floating. When the press arm is at rest, the adjustable link is stopped by and rests on the frame. As it is stopped, gravity pulls the adjustable link rearwardly, disengaging the pulley from contact with the frame. This allows the cable routed over such pulley to be used with a different exercise when the press arm is not in use. The rotation of the pulley caused by the cable is in the same rotational direction caused by it rolling along the frame member. The invention keeps the press handles in the same position relative to the main pivot, and does not introduce additional friction due to more pivots, and produces a stable pressing motion because the adjustment link does not float. The invention also enables economy of manufacture because of fewer parts.

Exercise device with adjustable press arm


The present disclosure relates to a hydraulic system for construction machinery, which is applied to construction machinery provided with a steering unit for controlling steering of equipment, and a main control valve for controlling operating of a work tool, and includes: a main pump for discharging working fluid supplied to the steering unit and the main control valve; a load sensing pressure sensor for sensing a load sensing pressure of the steering unit; a priority valve installed in a supply passage for the working fluid discharged from the main pump, for dividing and supplying the working fluid discharged from the main pump to the steering unit and the main control valve, to correspond to the load sensing pressure; an auxiliary pump for supplementing working fluid to the supply passage supplying the working fluid divided by the priority valve to the steering unit; an electric motor for operating the auxiliary pump; and a controller for operating the electric motor when the load sensing pressure is greater than a reference load sensing pressure, and additionally supplying working fluid discharged from the auxiliary pump the steering unit.

In general, construction machinery such as a wheel loader uses working fluid discharged from a hydraulic pump connected directly to an engine to operate a steering unit and a work tool. In particular, hydraulic systems that supply working fluid discharged from one hydraulic pump simultaneously to a steering unit and a work tool are currently in use. In such hydraulic systems, working fluid supplied to a steering unit and a work tool should be efficiently distributed, and an example of such distribution is shown in FIG. 1.
Referring to FIG. 1, working fluid discharged from a hydraulic pump 1 passes through a priority valve 2 and is supplied to a steering unit 3 and a main control valve 4. The working fluid supplied to the main control valve 4 is controlled in flow direction and supplied to an actuator of a work tool. The priority valve 2 is set to supply working fluid to the steering unit 3 first, and when a load sensing pressure (LS) of the steering unit 3 becomes low, the flow supplied to the main control valve 4 is increased and the flow of working fluid supplied to the steering unit 3 is reduced.
However, even when working fluid is first supplied to the steering unit 3 as described above, because an absolute flow of working fluid discharged from the hydraulic pump 1 is deficient when engine rpm is in a low range, the flow of working fluid supplied to the steering unit 3 is reduced. As a result, much effort is required to control the steering wheel, causing much difficulty in controlling the steering wheel.
The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.

Hydraulic system for construction machinery


A hybrid external cavity laser and a method for configuring the laser having a stabilized wavelength are disclosed. The laser comprises a semiconductor gain section and a volume Bragg grating, wherein a laser emission from the semiconductor gain section is based on a combination of a reflectivity of a front facet of the semiconductor gain section and a reflectivity of the volume Bragg grating and the reflectivity of the semiconductor gain section and the volume Bragg grating are insufficient by themselves to support the laser emission. The hybrid cavity laser further comprises an etalon that provides further wavelength stability.

Relative to other laser designs, diode lasers are more compact and robust, less expensive, electrically more efficient, radiate less waste heat, and easier to use as they do not require long warm-up times or great amounts of power (e.g., kilowatts) to operate. Overall, laser diodes offer a lower cost alternative for many applications. Until recently, however, diode lasers could not be used in products that require extremely high spectral stability and ultra-low wavelength drift due to strong temperature-dependence of the semiconductor material from which they are made. Single longitudinal mode diode lasers, such as distributed feedback (DFB) losers, exhibit a temperature dependence of their optical emission wavelength of about 0.07 nm/° C This temperature dependence alone makes the use of laser diodes difficult and costly in applications requiring a high degree of wavelength stability.
The use of volume holographic gratings, also termed VOLUME BRAGG GRATING (VBG), to stabilize the output wavelength of one or more diode lasers is known in the art as described, for example, in U.S. Pat. No. 7,889,776. VOLUME BRAGG GRATING and VBG are registered Trademarks of PD-LD Inc., Pennington, N.J.
FIGS. 1A and 1B represent side-view and top view, respectively, schematic illustrations of diode lasers of this type, often termed "hybrid external-cavity lasers" or HECLs in the art. In such lasers, a semiconductor gain section gain section, 110, provides optical gain. The optical radiation emitted from the semiconductor material (i.e., chip) diverges both perpendicular to and parallel to the epitaxial layer structure of the semiconductor gain section. The perpendicular direction is often termed the "fast axis", as the radiation pattern in that direction diverges at greater angles than the divergence in the parallel direction, often termed the "slow axis". Optics are used to collect and collimate the diverging beam. These optics are often termed a "fast axis corrector" (i.e., FAC), 120, and a "slow axis corrector" (i.e., SAC), 130. The FAC, 120, is typically located between the laser chip and the VBG, 140. The SAC, 130, may be located between the FAC 120 and VBG 140, as shown in FIGS. 1A and 1B. Alternatively, the SAC 130 may be located on the output side of the VBG (see for example FIGS. 2A and 2B, where the SAC 230 is on an output side of the VGB 240). FIGS. 2A and 2B represent side and top views, respectively of a HECL wherein the SAC is positions on the output side of the VRB. As the element of FIGS. 2A and 2B are substantially the same as those described with regard to FIGS. 1A and 1B, a detailed discussion of the elements of FIGS. 2A and 2B need not be further described.
Returning to FIGS. 1A and 1B, the reflectivity of the coating applied to the rear facet of the semiconductor gain section, R1, 111, located at a position z1 in FIG. 1, is high; typically 90-98% at the laser wavelength. The reflectivity of the front facet, R2, 112, is typically several percent or more. For example, U.S. Pat. No. 7,298,771 teaches a self-seeded HECL where the gain section operates as a laser and where the reflectivity of a front facet, R2, 112, may be in the range of 0.5-20% at the laser wavelength.
To a degree, a VBG-stabilized laser, shown in FIG. 1, may operate on a single longitudinal mode by using the VBG element as a partially reflective output coupler. The spectral reflectivity of the VBG element is substantially narrower than the width of the gain curve of the active medium of the laser. Only the longitudinal modes of the laser cavity with sufficient gain to exceed the lasing threshold will oscillate and be amplified. In some cases, the output of the laser module will consist of a single longitudinal mode.
In the conventional HECL shown in FIG. 1, the front and back surfaces of the collection/collimation optics, FAC and SAC, as well as the entrance and exit surfaces of the VBG 140 are anti-reflection coated so that the role of reflections from these surfaces does not contribute significantly to establishing optical cavities. The reflectivity of the wavelength selective feedback element (i.e., the volume Bragg grating of FIG. 1) is high relative to the reflectivity of the front facet of the gain chip, and thus a simplified analysis in which the front facet is ignored may be applied. In that case the functional optical cavity is established between the rear facet of the semiconductor gain section, at position z1, and the effective position of the VBG, which is determined by the length of the VBG, the refractive-index variations of the VBG, and the periodicity of the contained Bragg grating. The optical cavity established by these reflections is shown as having a length L2, 162, in FIG. 1, which defines a Fabry-Perot etalon. The spacing of transmission and reflection maxima produced by a Fabry-Perot etalon is:
                              Δ                                                                          v            C                          =                  c                      2                                                                          O                                                                          P                                                                          L                                              (        1        )                            where c is the speed of light in vacuum;        OPL is the optical path length.
OPL is determined by the summation of the physical path length, Li, multiplied by the effective refractive-index, ηi, of each segment of the optical path.
In the HECL shown in FIG. 1, the semiconductor gain section having a physical length of 1.5 mm (millimeter) and a refractive index of approximately 3.5 (at a wavelength, λ0 of 1.064 μm), the effective length of the VBG may be approximately 1.5 mm with a refractive-index of approximately 1.5; the total thickness of the FAC and SAC may be approximately 2 mm with a refractive-index of approximately 1.5; and the total effective physical length of the Fabry-Perot cavity may be approximately 10 mm. The OPL is then approximately 15.5 mm, as shown in Table 1.
TABLE 1LiηiLi(mm)ηi(mm)Gain section22.214.171.124FAC + SAC2.01.53.00VBG220.127.116.11Free Space5.01.05.00OPL15.50
The free spectral range of such a cavity, given by Eq. 1, is ΔνC approximately 9.7 GHz, or ΔλC approximately 37 pm (picometers) at λ0=1.064 μm (micrometers).
The principle by which a conventional HECL operates is illustrated in FIG. 3.
As shown in FIG. 3, the semiconductor gain section, 110 (of FIG. 1A, 1B) has a gain profile, 310 that is broad. Typically, the full-width at half-maximum of the gain profile (i.e., 3 db points) can be 30 nm (nanometers) or greater.
The laser cavity formed by R1, 111, and the VGB, 140, having a length of L2, 162, in FIGS. 1A, 1B supports many modes, indicated by the set of discrete modes 360 of FIG. 3. In conventional practice, the HECL is configured so that only one mode, 361, of the set of discrete modes 360, is at a wavelength for which the diode chip gain exceeds a lasing threshold, 365; such that a lasing output is achieved. The HECL will, preferentially, operate on that cavity mode. That is, generate a lasing output at wavelength λ0.
Also shown in FIG. 3 is the spectral reflection profile, 340, of the VBG, 140 (of FIG. 1A). Although the spectral reflection profile, 340, of the VBG gain profile is shown as centered with respect to the gain profile 310, it will be appreciated that the spectral reflection profile, 340, of the VBG gain profile does not need to be centered with respect to the gain profile, 310, of the laser chip. Generally the VBG profile is often offset with respect to the laser chip profile. The width of the spectral profile of the VBG, ΔλVBG, 341, is considerably narrower than that of the diode laser gain profile, 310, and can be determined by the number of Bragg grating planes, N, formed in the VBG:ΔλVBG/λ0≈N  (2)
In a VBG having a length of approximately 3 mm, with Bragg grating planes spaced by λ0,/2n, where n is the refractive-index of the material, N may be of the order of 104, at λ0=1.064 μm. Thus, ΔλVBG is approximately 100 pm.
A Fabry-Perot resonator such as that formed by the R1, 111, and the VBG 140 may be further characterized by peaks in the transmission which correspond to cavity resonances within the etalon, and hence the allowed lasing modes of the cavity. A description of the transmission of light through a Fabry-Perot etalon is schematically depicted in FIG. 4 as curve 450. The transmission of light, T, can be expressed by:
                    T        =                                            (                              1                -                                                                            R                      1                                                                                R                      2                                                                                )                        2                                1            +                                          R                1                                                          R                2                                      -                          2                                                                                R                    1                                                                          R                    2                                                                                cos                                                  (                                                            4                                                                                π                                                                                n                                                                                L                                        λ                                    )                                                                                (        3        )                            where n is the refractive index of the medium                    L is the path length,            λ is the wavelength of light,            R1 is the reflectivity of the rear facet of the resonant cavity, and            R2, in this case, may represent RVBG.
An exemplary HECL operating at λ=1.064 μm, with the laser chip having a rear reflectivity R1 of approximately 0.9 may have a VBG with a length of 3 mm and a reflectivity, RVBG approximately equal to 0.3. For the purposes of this simplified calculation, n=1, and L=15.5 mm. The resultant Fabry-Perot etalon has a finesse, i.e. a ratio of the free spectral range, ΔλC, to the full width at half-maximum of the spectral distance between resonance, of approximately 4.8.
Referring to FIG. 4, a subset of the set of resonant wavelengths of the Fabry-Perot etalon is denoted as 460. The set of cavity resonances arising from reflections from R1 and the VBG now are depicted as having finite width, and are shown as the shape 460 in FIG. 4. Superposed on the cavity resonances 460 is the spectral profile 441 of the emission reflected from the VBG, which is sufficiently narrow relative to the spacing of the cavity resonances so that only one cavity mode, 461, exceeds the gain threshold for lasing. The HECL will, therefore, oscillate at the wavelength of that cavity mode, λ0, 470.
Such operation, however, is not stable with respect to minor variations in operating parameters, such as variations in laser power, the temperature of the VBG, and thermal expansion of the optical cavity. In addition, instabilities often result from laser emission from the semiconductor gain section acting as a laser on its own. In the prior art disclosed here, HECL systems with VBGs are designed such that the semiconductor gain section is a laser. For example, in U.S. Pat. No. 7,298,771 the use of a laser diode in conjunction with a VBG, such that the reflected light from the VBG only causes a narrowing of the emission spectrum of the laser diode. This design has significant shortcomings, however, as the laser diode is operating without any reflected light from the VBG. The reflectivity from the Bragg grating simply narrows the existing laser emission. Thus, as the laser diode drive is varied to vary the output of the diode, instabilities may be introduced due to variations in spatial modes and gain saturation, leading to mode hops and linewidth broadening. The devices can even operate such that emission from the lasing of the semiconductor cavity occurs simultaneously with emission from the cavity formed by the VBG. An example of this mode of operation may be found in E Kotelnikov et al, Proc. of SPIE Vol. 8277, 2012. Similar effects can occur due to temperature variations.
The basic principles of operation of VBG-stabilized HECLs as described in the prior art are insufficient to guarantee single-longitudinal mode operation. In fact, relatively small values of the front-facet reflectivity, R2 (112 in FIG. 1A), result in resonances in the semiconductor gain section defined by its own Fabry-Perot cavity, independent of the HECL cavity formed by the VBG element. The value of R2 at which such self-oscillation occurs depends on the gain of the semiconductor gain section (and the value of R1), and can occur even at a reflectivity of a few percent or less. Furthermore, laser oscillation on multiple modes of the HECL cavity have been observed even when the value of R2 is as low as 0.5% for devices with long gain sections at high drive current. In such cases, the laser mode hops between allowed modes oscillating at different wavelengths (i.e., wavelength hopping).
FIG. 15 is a spectrum of the output of an external cavity laser incorporating a multi-spatial-mode gain section with feedback from a VBG element, constructed according the teachings of U.S. Pat. No. 7,298,771 and, therefore, operating by self-seeding. As can be seen from the spectrum, the output wavelength of these devices is not locked to a single, stable wavelength. Rather, evidence of oscillation at several distinct modes can be seen in spectral peaks at wavelengths λ1 1501, λ2 1502, λ3 1503, and λ4 1504, as well as additional subsidiary spectral peaks of lower intensity.
Hence, a hybrid external cavity laser that provides substantially increased stability and reduced linewidth of generated laser light is needed in the industry.


There is provided a system and method for coupling with a shaft. In particular, there is provided a friction shaft coupler that includes a center plate and a plurality of outer plates, wherein the outer plates are configured to abut the center plate. The center plate and the plurality of outer plates each include a shaft bore configured to receive a shaft and a plurality of stub bores. The friction shaft coupler also includes a plurality of stubs, wherein each stub is configured to fit inside one of the plurality of stub bores, the plurality of stubs comprising a plurality of apertures that are perpendicular to a longitudinal axis of the stubs. Additionally, the friction shaft coupler includes a plurality of set screws configured to fit inside the apertures of the stubs, wherein the set screws are accessible for adjustment via access holes in the plurality of outer plates.

1. Field of the Invention
The present invention relates generally to shaft couplings and, more particularly, to shaft couplings with adjustment means perpendicular to the shaft.
2. Description of the Related Art
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present invention, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
Shafts are used in many different mechanical devices and may be used for different purposes. For example, a drive shaft may be used to transfer torque from a combustion engine to wheels of a vehicle to move the vehicle. Alternatively, a shaft may be used as a support member to hold other members or devices in a particular position and/or, in some instances, may be used as an axis for rotation. In yet other applications, a bearing housing may be attached to the shaft to reduce the amount of friction caused by rotation of a shaft.
Additionally, although shafts may take on several different shapes, one common shape is a cylinder. Many applications that use cylindrical shafts require a component or member to be coupled to the shaft so that it may move in conjunction with the shaft (or vice-versa) and/or so that it does not move longitudinally along the shaft, among other reasons. Several different techniques have been developed to rigidly couple components or members to cylindrical shafts. For example, keys, spines, and flats are common shaft configurations that allow for a rigid coupling with a cylindrical shaft. Generally, keys, spines and flats are non-circular portions of a shaft that corresponds with non-circular portions in a bore of the member that is to be coupled with the shaft. The non-circular portions of the shaft and the member coupled to shaft allow for the member to move in conjunction with the shaft. The resultant fit between the shaft and the bore produces large radial forces applied by the bore of the coupling member normal to the shaft diameter, which locks the coupled member to the shaft.
An alternative technique is an interference fit, wherein the shaft and the bore of the member coupled to the shaft are manufactured to have a very tight tolerance. Stated differently, the bore does not provide much clearance for the shaft. Because of the tight tolerance, the coupling of the member and the shaft requires the application of a high amount of pressure, the temporary expanding of the bore through heating, or a combination of pressure and heat to allow the shaft to fit into the bore.
Another alternative technique for coupling members to a cylindrical shaft is using a split ring and bolt or screw. The split ring fits around the shaft and is clamped down on the shaft by tightening the bolt or screw. Producing a frictional coupling. An alternative technique involves using one or more set screws, or similar threaded devices, within the coupled member which, when tightened, bear directly on the shaft, and produce a frictional or mechanical coupling.
The use of keys, spines, flats, interference fits, and/or split ring couplers have disadvantages, however. First, the use of keys, spines or flats includes modifications to the shaft that may weaken the shaft. Similarly, because the split rings are not unitary members, they may lack structural integrity. Set screws, which bear directly on the shaft, often cause damage to the shaft. It may also be difficult to configure sufficient quantity and screw size to intersect the shaft and generate the desired frictional force. Alternatively, the use of an interference fit may increase the difficulty associated with assembling the shaft and member, as well as complicating the replacement of the member or the shaft.
Embodiments of the present invention may address one or more of the issues mentioned above.

Friction shaft coupling with perpendicular adjustment


A covalently linked linear porphyrin polymer represented by formula (1):

1. Field of the Invention
The present invention relates to a novel porphyrin dimer or higher porphyrin polymer. The present invention also relates to a method of producing the same.
Further, the present invention relates to another porphyrin dimer and a porphyrin monomer which constitute the porphyrin polymer of the present invention.
The porphyrin polymer of the present invention is expected to function as an element for efficiently capturing and transferring light energy. It is contemplated that the porphyrin polymer of the present invention is applied to an artificial photosynthesis element and an organic solar battery. Porphyrin is also known to function as a light-induced electron transfer element. Therefore, it is expected that the porphyrin polymer of the present invention can be applied to a light/electron element of a molecular size.
2. Description of the Related Art
Porphyrin is a cyclic tetrapyrrole in which four pyrrole nucleuses are connected with four methine groups. As porphyrin has a large conjugated system including eighteen π electrons, it is expected that a porphyrin polymer can be used as a material of molecular wire or the like. Some examples of synthesizing a porphyrin polymer have been reported.
For example, Osuka of Kyoto University and Sugiura of Tokyo Metropolitan University have reported methods of extending a porphyrin polymer chain by way of covalent bonds (K. Sugiura, H. Tanaka, T. Matsumoto, T. Kawai, Y. Sakata, Chem. Lett. 1999, 1193; N. Aratani, A. Osuka, Y. H. Kim, D. H. Jeong, D. Kim, Angew. Chem. Int. Ed. 39, 1458 (2000); and A. Tsuda and A. Osuka, Science, 293, 79 (2001)). However, each of these methods requires a synthetic process with a very large number of steps, which is economically disadvantageous. Further, in these methods, a porphyrin polymer having up to hundreds of porphyrin units can hardly be synthesized.
The inventors of the present invention have already discovered that imidazolylporphyrin metal complexes form a coordinate bond with each other, between molecules, thereby forming a porphyrin dimer or a higher porphyrin polymer (refer to the following reaction formulae 1 and 2, and Y. Kobuke, H. Miyaji, J. Am. Chem. Soc. 1994, 116, 4111; K. Ogawa, Y. Kobuke, Angew. Chem. Int. Ed. 2000, 39, 4070; and Japanese Patent Application KOKAI Publication No. 2001-213883, which corresponds to U.S. Pat. No. 6,429,310B1, the entire contents of which are incorporated herein by reference, and Patent Application KOKAI Publication No. 2001-253883, the entire contents of which are incorporated herein by reference, which corresponds to U.S. Ser. No. 09/802,923, filed Mar. 12, 2001). Each of these porphyrin polymers functions as an energy-transferring element and thus is expected to be applicable to a molecular electronics element.

The unique and advantageous feature of a porphyrin polymer constituted of imidazolylporphyrin metal complexes as its constituting units lies in that the porphyrin polymer is self-organized only by mixing imidazolylporphyrin monomers in a non-polar solvent. Accordingly, the only material that is sufficient to synthesize porphyrin polymer is porphyrin monomers, which are the smallest constituting units (refer to the above-mentioned reaction formulae 1 and 2). As compared with the methods of Osuka and Sugiura in which a porphyrin polymer chain is extended by way of covalent bonds, this method requires a smaller number of synthesis steps, and thus is more economical. According to the method, it is actually possible to produce an extremely large metal complex polymer having a molecular weight of 500,000 or so, in which the metal complexes are regularly arranged. However, in this method, the porphyrin polymer extended by coordinate bonds tends to have the coordinate bond thereof cut in a polar solvent, and there arises a problem that the medium and environment applicable to the resulting porphyrin polymer are limited to non-polar ones. This limitation significantly restricts the scope of application of the porphyrin polymer (refer to the reaction indicated by the arrow showing the shift from right to left, of the above-mentioned reaction formula 1). Therefore, it has been desired to synthesize a stable porphyrin polymer in which the porphyrin polymer chain is extended by way of coordinate bonds, is firmly fixed and the coordinate bonds thereof are no longer cut after the polymer formation.

This patent is subject to a terminal disclaimer.

Covalently fixed porphyrin polymer having porphyrin metal complex substituted with coordinating hetero aromatic ring as constituting unit thereof,and method of producing the same

Abstract: wherein                R represents an alkyl group or

Abstract: (wherein a, b and d independently represent H, an alkyl group or aryl group);        X represents —O—, —S—, >NR101 (wherein R101 represents H or an alkyl group), —CH2— or a single bond;        Y represents ═O, ═S, or 2H;        m represents an integer of 0 to 4;        n represents an integer of 0 to 6;        Z represents a five- or six-membered, nitrogen-containing, coordinating hetero aromatic ring group;        M represents an ion of metal selected from typical metals and transition metals;        Q1 represents a single bond or a linear, divalent linking group; and        p1 represents an integer of 2 or more.

Nara Institute of Science and Technology


A method and device to reduce the noise produced by jet aircraft engines and/or other supersonic nozzles involves the use of corrugated engine seals (30) for the secondary internal divergent flaps (14) of the nozzle (10). Such corrugated seals (30) serve not only to eliminate shock-generated noise, but also generate a counter-rotating vorticity to force low speed mixing of surrounding ambient air with the high-speed jet exhaust. Lower exhaust velocities, combined with reduced levels of the turbulent Reynolds shear stress, lead to reduction of turbulence-generated noise, including Mach wave emission.

The method and device of the present invention has particular applicability for the jet engines of a military aircraft, such as the U.S. Navy's F/A-18 E/F Super Hornet aircraft in performance of the Field Carrier Landing Practice (FCLP) mission profile. During performance of the FCLP mission profile, military aircraft, such as the F/A-18 E/F, operate with variable area engine nozzles which are scheduled to be highly overexpanded. This means that the nozzle exit static pressure is significantly below the surrounding ambient pressure at the aircraft's altitude above ground level. This overexpanded exhaust flow contains shocks in the exhaust plumes, the presence of which generates an efficient noise production mechanism known as "shock noise." For a further discussion of shock noise, reference is made to Seiner, J. M., 1984, "Advances in High-Speed Jet Aeroacoustics," Invited Lecture, AIAA Paper No. 84-2275. This publication is incorporated herein by this reference.
Furthermore, it is well-recognized that an overexpanded nozzle has a lower aerodynamic performance efficiency than one that is fully expanded, i.e., where the exhaust static pressure equals the local aircraft ambient pressure. See Liepman, H. W., and Roshko, A., 1985, "Elements of Gasdynamics," Dover Publications, Inc., Mineola, N.Y., a publication which is also incorporated herein by this reference. In any event, reduction of shock noise can generally be accomplished by design of the nozzle geometry to achieve fully expanded flow at the nozzle exit, where the exhaust static pressure is equal to ambient pressure.
In addition to shock noise, an additional efficient noise generating mechanism is present within a supersonic exhaust regardless of whether it contains shocks. This noise generating mechanism is referred to as Mach wave emission. See Seiner, J. M., Bhat, T. R. S., and Ponton, M. K., 1994, "Mach Wave Emission From a High Temperature Supersonic Jet," AIAA J., Vol. 32, No. 12, pp. 2345–2350, a publication which is also incorporated herein by this reference. To minimize this noise source requires that the high-speed exhaust be forced to mix with the slower moving surrounding air to achieve lower velocities in the exhaust plume than would otherwise occur naturally. Lower exhaust velocities, combined with reduced levels of the turbulent Reynolds shear stress, lead to reduction of turbulence-generated noise, including Mach wave emission.
Accordingly, it would be desirable to provide a method and device to substantially reduce shock noise by providing a nozzle design and construction to achieve fully expanded flow at the nozzle exit, while at the same time, generating the appropriate counter-rotating vorticity to force low speed mixing of surrounding ambient air with the high-speed exhaust to reduce turbulence-generated noise.

Method and device for reducing engine noise


Methods and apparatus are provided for protecting an unattended parked vehicle from being impacted by a moving vehicle under control of a driver. The apparatus comprises a detection and alarm system built into the unattended parked vehicle. When a moving vehicle comes within a predetermined distance from the unattended parked vehicle, the apparatus senses the presence of the moving vehicle and activates the alarm system. If the moving vehicle continues to approach the unattended parked vehicle, the activated alarm signals are increased in intensity. Typically, the alarm signals would be in the form of lights flashing and/or horn blowing, or any appropriate combination of audible and visual signals.

Minor collisions between moving vehicles and unattended parked vehicles are common occurrences in areas such as parking lots. While the damage from this type of collision is not usually extensive, since the moving vehicle is usually maneuvering slowly into or out of a parking space, even a minor collision can prove to be an unpleasant and costly experience for the owner of the parked vehicle, as well as for the driver of the moving vehicle. Moreover, as the vehicle population increases, and as the variations in vehicle size and shape increase as well, the potential for collisions of this type is also likely to increase.
Recent developments in automotive technology involve the use of ultrasonic distance detectors installed on a vehicle. Typically, the purpose of this type of distance detector is to warn the driver of an impending contact with another object. For example, ultrasonic sensors can be placed on the bumpers and sides of a vehicle to enable the determination of distances between the vehicle sensors and another object, such as a parked car or a tree. When a detector-equipped vehicle is within a predetermined distance from an object, an alarm can be activated to warn the driver of the situation. As such, the driver of an appropriately equipped vehicle can be alerted in time to avoid a collision with a nearby object.
In general, however, such distance detection systems are only active when a vehicle is being driven, and are typically placed in an off state when the vehicle ignition is turned off, as in a parking situation. In addition, most automotive vehicles are not yet equipped with distance detection systems, so there is usually no type of active warning system in place for the kind of situation where an unequipped vehicle is maneuvering in the proximity of parked vehicles.
Even if a parked vehicle is equipped with a distance detection system, the sensing process will be typically inactive, since the system is normally turned off when the vehicle is parked. Therefore, it is desirable to incorporate a type of detection system in a parked unattended vehicle that can be operative after the ignition is turned off, to warn an approaching driver of the possibility of an impending collision.
Accordingly, it is desirable to provide a collision avoidance system for a vehicle that can be operative when the vehicle is in a parked (ignition off) state. In addition, it is desirable to implement this type of collision avoidance system with available technology and hardware, to minimize manufacturing production costs. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.

Collision avoidance of unattended vehicles