Methods and systems for producing aromatics and light olefins from a mixed plastics stream are described. The method may include feeding a plastic feedstock to a dechlorination operation to melt the plastic feedstock to release HCl and generate a liquid plastic stream; feeding the liquid plastic stream to a pyrolysis reactor, the pyrolysis reactor to generate hydrocarbon vapors; feeding the hydrocarbon vapors to an acid gas removal reactor with a solid inorganic alkali salt disposed within the reaction vessel to remove residual HCl and sulfur-containing compounds from the hydrocarbon vapors to generate a plastic derived oil; and feeding the plastic derived oil to a steam enhanced catalytic cracking reactor to generate a product stream comprising light olefins having a carbon number of C2-C4 and aromatics. The associated system for processing mixed plastics into aromatics and light olefins is also described.

Field
The present disclosure generally relates to processes and systems for producing aromatics and light olefins from a mixed plastics stream, and more specifically, to processes and systems to producing aromatics and light olefins from a mixed plastics stream through steam enhanced catalytic cracking of plastic derived oil having undergone removal of acidic gases and contaminants.
Technical Background
Plastic is a synthetic or semisynthetic organic polymer composed of mainly carbon and hydrogen. Further, plastics tend to be durable, with a slow rate of degradation, therefore they stay in the environment for a long time and are not prone to rapid breakdown upon disposal. Pure plastics are generally insoluble in water and nontoxic. However, additives used in plastic preparation are toxic and may leach into the environment. Examples of toxic additives include phthalates. Other typical additives include fillers, colorant, plasticizers, stabilizers, anti-oxidants, flame retardants, ultraviolet (UV) light absorbers, antistatic agents, blowing agents, lubricants used during its preparation to change its composition and properties.
Plastics pyrolyze at high temperatures and polymers can be converted back to their original monomers or smaller polymers as gas or liquid and can be recovered. However, the additives added to the plastic during production present challenges in effectively utilizing the recovered products from pyrolysis. Upon pyrolysis, the additives end-up in the pyrolysis products and thus require further processing to generate feed streams for conversion useful products.

Processes and systems for producing light olefins and aromatics from a mixed plastics stream


A controlling apparatus for an electric motor according to an embodiment includes a superposed component generator, an inverter, a current detector, and a magnetic pole position estimator. The superposed component generator generates, at a predetermined cycle, a superposed voltage reference of which vector is shifted by 90 degrees with respect to that of a superposed voltage reference previously generated, in a coordinate system that is set to a stator of the electric motor. The inverter outputs a driving voltage that is based on a driving voltage reference superposed with the superposed voltage reference to the electric motor. The current detector detects currents flowing into respective phases of the electric motor, and outputs the detected currents. The magnetic pole position estimator detects the magnetic pole position of the electric motor based on an amount of change in the detected currents at the predetermined cycle.

Magnetic pole position estimating apparatuses for estimating the position of the magnetic poles in a salient electric motor have conventionally been known. A known example of such magnetic pole position estimating apparatuses estimates a magnetic pole position in an electric motor by superimposing a high frequency component on a pulse-width modulated (PWM) signal.
The magnetic pole position estimating apparatus disclosed in Japanese Patent No. 4670044, for example, estimates a magnetic pole position in an electric motor by generating a PWM signal to be applied to the respective three-phase windings in the following fashion. Considering successive three cycles of a carrier as one interval, the magnetic pole position estimating apparatus multiplies each original reference value by three for one third of the period (the first one cycle of the carrier), and superposes a high-frequency component for the remaining two third of the period (the remaining two cycles of the carrier).
The magnetic pole position estimating apparatus disclosed in Patent Literature 1, however, can update the original reference values for driving the electric motor only once in the three-cycle unit of the carrier.

Magnetic pole position estimating apparatus for electric motor, controlling apparatus for electric motor, and magnetic pole position estimating method for electric motor


Disclosed is a method for configuring an intrusion detection system in a network which comprises determining a location in the network for a deployed intrusion detection sensor of the intrusion detection system, deploying the intrusion detection sensor in the determined location, enabling the intrusion detection sensor to monitor communication in a portion of the network, tuning the intrusion detection sensor to an appropriate level of awareness of the content in the communication in the network, prioritizing responses generated by the intrusion detection sensor to achieve an appropriate response to a detected intrusion in the network, configuring intrusion response mechanisms in the network to achieve an appropriate response by the mechanisms; and re-tuning the intrusion detection sensor in response to a prior intrusion detection.

Modern networking continues to provide communication and information access increases and improvements. The continuing growth of networking systems and technology seems limitless and the speed of networked communications has brought benefits to nearly every human endeavor.
In addition to the inherent complexities of network communications, recent trends in information technology have seen large enterprises and other users moving towards a centralization of some network services, notably data storage and mining as well as some more complex applications. This centralization is realized in many instances by contracted access to provisionable, or virtually reconfigurable, networks. A provisionable network allows a centralization of information technology (IT) services and enterprise-wide, and even internet-wide, access to specialized data and functions. The various moves to re-centralize IT systems of all kinds is driven in part by shortages in IT staff and by the intrinsic inefficiencies of distributed systems. Notably, many IT managers are migrating to a smaller number of large data centers. Enabled by abundant and relatively inexpensive network bandwidth, IT services can now be distributed to users globally. The need to nest server-side technology near the client workstation is lessening, which has led to this dramatic change in IT architecture.
Security of networks has been a concern since before the first important data storage in an accessible computer system. Even more than earlier distributed networks, provisionable networks are exposed to possible security lapse and even attack through the multitudinous communications links such systems entail. Because there is necessary communication within and between resources contained within the provisionable data center, as well as communication with clients outside the network, the possible avenues of security failure are many.
In addition to "normal" hacker attack, security breaches can consist of such things as the unauthorized entry into a portion of a database by an otherwise authorized user or the unauthorized use of an application managed by the center. An example of this could be use by a foreign engineering entity of a supercomputer computational fluid dynamics facility, perhaps barred by technology exchange law, wherein the foreign entity's use of other portions of the same provisionable data center is legitimate and desirable.
Another example involves a case wherein there are competing clients legitimately served by the UDC and who share some of the available resources, such as a marketing database. These same two clients may also employ the UDC for secure archiving of proprietary data that neither wants the other to access. Furthermore, the management system of a provisionable data center itself could be the target of a focused intrusion whose goal could be the weakening of the management structure to enable other intrusions.
A technology of intrusion detection has grown in company with that of the provisionable network. Network intrusion detection systems (NIDS) and their management infrastructures are now as complex as the networks they protect.
Designing and deploying a Network Intrusion Detection System (NIDS) for providing effective attack detection capabilities to an infrastructure is an extremely difficult task. Apart from the minor difficulties of understanding how and where to physically deploy NIDS sensors, the major difficulty is in understanding where sensors should be most effectively deployed and, more importantly, how to configure the NIDS sensors. Configuration of NIDS sensors, in terms of enabling the proper intrusion attack signatures, assigning the correct severities to them, and associating the most effective responses to those alerts, has not been documented as a streamlined, guided, process and in its absence most configurations are either done with the default settings or by tuning them with production environment observations. Default sensor settings are unreliable across the installation spectrum and NIDS often deal with storms of false positives when used with a default configuration. Even though tuning the NIDS in the production environment over a period of time is desirable if used for the final tuning, using the process for fully configuring a NIDS sensor can prove disastrous in terms of false negatives as also very time consuming and requiring continuous periodic tuning.
In the absence of a clear streamlined guided process, NIDS sensors have been either configured with default settings or tuned in production environments. Using default settings can only be relied (and that too minimally owing to usage in disparate environments) for their severities and would surely result in a storm of false "positives" if used with the default configuration. On the other hand, tuning the NIDS in the production environment over a period of time for fully configuring an NIDS sensor could prove disastrous in terms of false "negatives" as also very time consuming and requiring continuous periodic tuning. Also in the absence of any standardized framework for assigning severities or associating response actions, even an NIDS solution that uses excellent sensors looses its effectiveness because of inconsistencies in its alerting and response.
What is needed, then, is a method for configuring network intrusion detection sensors in a network such that the management components of the network are protected from intrusions that originate from either an external source, or from the systems within a less trusted part of the network management infrastructure. Such a configuration method should enable the cost effective deployment of sensors that are tuned to determine and discriminate between the threat levels of detected intrusions and to be able to generate an appropriate response to a detected intrusion.

Method for configuring a network intrusion detection system

Hewlett-Packard Development Company, L.P.


A wireless network comprises a plurality of nodes that communicate over wireless communication links. A virtual site is established at a primary node included in the plurality of nodes. A backup node is selected for the virtual site from the plurality of nodes. When the primary node is able to do so, the primary node performs predetermined processing for the virtual site and replicates at the backup node data related to the processing. When the primary node is unable to perform the processing, the backup node performs the processing for the virtual site using at least some of the data replicated at the backup node.

A wireless network typically includes several nodes that communicate with one another over wireless communication links (for example, over radio frequency communication links). One type of wireless network is a wireless sensor network in which one or more of the nodes are "sensor nodes" (also referred to here as "wireless sensor nodes"). Each sensor node incorporates (or is otherwise coupled to) a sensor. Each sensor is capable of generating a value that, at any given point in time, is indicative of some physical attribute of interest. In one configuration, the sensor nodes are battery powered and have limited computational resources (for example, limited memory and processing capability).
Data is typically retrieved from a wireless sensor network by querying the wireless sensor network for such data. Data specified in a query is retrieved from (or is otherwise generated at) one or more nodes in the wireless sensor network. The retrieved and/or generated data is returned to a recipient specified in the query.
A query can specify that various types of data are to be retrieved and/or that various types of operations are to be performed. One type of operation that can be specified in a query is an "aggregation operation" (also referred to here as "data aggregation" or "aggregation"). An aggregation operation generates a value as a function of multiple items of data. Each of the items of data is also referred to here individually as an "input item" and collectively as "input items" or "input data". The multiple items of data can comprise multiple values from a single data source and/or can comprise values from multiple data sources. Examples of data aggregation operations include an "average" operation that calculates the average of the input data, a "minimum" operation that determines the value of a minimum input item, and a "maximum" operation that determines the value of a maximum input item.
In one such configuration, a particular node in the wireless sensor network is selected to perform each aggregation operation. Such a node is also referred to here as an "aggregation node." The aggregation node receives input data from other nodes in the wireless sensor network (if necessary) and then performs the aggregation operation on the received input data. However, if the aggregation node should fail or otherwise be unable to perform the aggregation operation or communicate with other nodes in the wireless sensor network, such a query will fail.
The failure of a node can also impact other processing that is performed in a wireless network (for example, a wireless sensor network). For example, in one configuration, a wireless network is logically arranged into a set of clusters. A node in each cluster is designated as the "head" node or "cluster head" for that node. For a given cluster, the cluster head tracks which nodes are members of that cluster and routes inter-cluster packets. In the event that a cluster head fails or is otherwise unable to perform the cluster head processing for that cluster, the performance of the wireless network is impaired (for example, until the failure is detected and a new cluster head becomes operational).
Such failures are of especial concern in wireless sensor networks that include batter-powered nodes and/or that make use of an ad-hoc configuration.


A method and system having one or more fractal antennas for communicating signals. The fractal antennas are coupled to a diversity receive circuit for receiving the signals. The diversity receive circuit provides an output signal based on a combination of the receive signals. The fractal antennas and the diversity receive circuit can help compensate for, or reduce the effects of fading. Additionally, a transmitter provides a transmit signal. One of the fractal antennas may both transmit and receive signals. Alternatively, a transmit antenna, separate from the receive antennas, may transmit the transmit signals. The fractal antennas may also be fractal arrays for providing additional resistance to fading.

1. Field of the Invention
The present invention relates generally to the field of wireless telecommunications and more particularly to wireless telecommunication antenna systems.
2. Description of Related Art
Wireless mobile stations, such as PCS and cellular telephones, WAP-enabled communication devices, personal digital assistants, IEEE 802.11 stations, cordless telephones, pagers, personal digital assistants (PDAs), two-way mobile radios (e.g. FRS-band radios), portable messaging devices (e.g., "Blackberry" devices) and wireless computers, have become widely used in society today. Suitably equipped, such a mobile station may connect a user to a network over an air interface, thereby enabling the user to engage in many useful voice and data communications without the need for a landline connection.
The mobile station will communicate over the air interface with a base station. To facilitate this communication, both the mobile station and the base station will include a respective antenna system. Commonly, a mobile station will employ a whip antenna, and a base station will employ several directional antennas so as to establish a radiation pattern that can encompass the mobile station.
Mobile stations and base stations may communicate with each other over various 20 frequencies. For example, traditional cellular telephones and cellular telephone networks have operated on two frequency bands (the "A" and "B" bands) centered around the 800 or 900 MHz frequency. And as another example, PCS devices and PCS networks have used six frequency bands ("A" through "F") centered around the 1800 or 1900 MHz frequencies. Other wireless communication systems and use of other frequencies for communication between a mobile station and a wireless network are possible as well.

Fractal antenna system and method for improved wireless telecommunications


A volumetric content enhancement system (“the system”) can annotate at least a portion of a plurality of voxels from a volumetric video with contextual data. The system can determine at least one actionable position within the volumetric video. The system can create an annotated volumetric video that includes the volumetric video, an annotation with the contextual data, and the at least one actionable position. The system can provide the annotated volumetric video to a volumetric content playback system. The system can obtain viewer feedback associated with the viewer and can determine an emotional state of the viewer based, at least in part, upon the viewer feedback. The system can receive viewer position information that identifies a specific actionable position of the viewer. The system can generate manipulation instructions to instruct the volumetric content playback system to manipulate the annotated volumetric content to achieve a desired emotional state of the viewer.

Volumetric video capture technology uses an array of cameras to capture video of a three-dimensional space, object, or environment. A user can view the volumetric video on a two-dimensional screen or in three-dimensions using an extended reality ("XR") headset, such as augmented reality ("AR") or virtual reality ("VR"), to further enhance the experience. The user can change their viewpoint to view the volumetric video from any angle. For example, in a volumetric video of a concert, the user may change their viewpoint from a fan in the crowd to a musician on stage. In addition to different angles, the user can zoom in and out to further enhance their experience with an increased sense of immersion.
As content is captured in rich media formats like volumetric video that incorporates three-dimensional spatial positions, the emotions experienced by the user may be different depending on how the content is consumed. For example, the user may change their viewpoint such that their distance from a three-dimensional object may change the audio and visual responses from the content. In another example, the user may experience different emotions based upon their viewpoint of the same scene or as a different character within the scene. Automated processing can modulate and enhance the video and/or audio in an attempt to provide a stronger or more subdued emotional impact on the user. It is a daunting task for content creators to determine and plan for all of the potential emotional states that users may experience versus their placement within the volumetric content. For this reason, the advantages of volumetric content over traditional content cannot be fully realized with current implementations, and in some instances, may detract from the user's immersion.

Enhanced emotive engagement with volumetric content


An etching gas is supplied into a process chamber and turned into plasma so as to etch a silicon nitride film arranged on a field silicon oxide film on a wafer (w). A mixture gas containing at least CH2F2 gas and O2 gas is used as the etching gas. Parameters for planar uniformity, by which the etching apparatus is set in light of a set value of the planar uniformity, include the process pressure and the mixture ratio (CH2F2/O2) of the mixture gas. As the set value of the planar uniformity is more strict, either one of the process pressure and the mixture ratio is set higher.

1. Field of the Invention
The present invention relates to a plasma etching method for preferentially etching a silicon nitride film (SiNx) arranged on a surface of a target object, such as a semiconductor wafer.
2. Discussion of the Background
In manufacturing processes of semiconductor devices, such as ICs and LSIs, predetermined circuit patterns are formed by subjecting a semiconductor wafer to film formation by means of, e.g., CVD (Chemical Vapor Deposition), and patterning by means of, e.g., etching. There is plasma dry etching as a representative of the etching processes. In plasma dry etching, a patterned photo-resist film is used as a mask and the exposed portion of an objective film is etched by an etching gas which has been turned into plasma.
In plasma dry etching, it is important to set the selectivity of an objective film to be etched, relative to a different kind of film not to be etched, to be as high as possible. Conventionally, a mixture gas of CHF3 gas and O2 gas is used to preferentially etch a silicon nitride film (SiNx) relative to a silicon oxide film (SiO2). This mixture gas is used along with Ar gas, which is a carrier gas. Where the mixture gas of CHF3 gas and O2 gas is used, the selectivity of SiNx relative to SiO2, i.e., (an SiNx etching rate) (an SiO2 etching rate) is about two at most. In this case, the selectivity of SiNx relative to Si, i.e., (an SiNx etching rate) (an Si etching rate) is also about two at most.
Where requirements on line widths and hole diameters are not so strict, a selectivity of about two does not cause serious problems. However, where the line widths and hole diameters are required to be of the sub-micron order, with an increase in the density and integrity degree of semiconductor devices, a selectivity of about two cannot satisfy the requirements.
Jpn. Pat. Appln. KOKAI Publication No. 8-59215 (U.S. Ser. No. 08/189027, now abandoned) discloses an etching method which uses a mixture gas of CHxF4xe2x88x92x (where x is 2 to 3,) and one or more oxygen-containing gases selected from a group consisting of O2, CO and CO2, in order to preferentially etch silicon nitride relative to silicon oxide, metal silicide, or silicon. In this etching method, preferably, the CHxF4xe2x88x92x consists essentially of CHF3, the oxygen-containing gas consists essentially of CO2, or both of them, and more preferably, CO2. As a result, this publication states that this etching method improves the selectivity, i.e., (an SiNx etching rate)/(an SiO2 etching rated), to be about four.
On the other hand, in plasma dry etching, it is important to keep the planar uniformity of etching high, the planar uniformity being defined by the difference between processed sizes at the center and the periphery of a target substrate. For example, it can be said that the planar uniformity is preferable where the difference between processed sizes at the center and the periphery falls within a range of xc2x17%, and more preferably within a range of xc2x15%. The selectivity and the planar uniformity have a trade-off relationship in terms of a certain parameter. Jpn. Pat. Appln. KOKAI Publication No. 8-59215 described above states a summary account about the selectivity, but does not at all consider the planar uniformity.
Accordingly, it is an object of the present invention to provide a plasma etching method which can present a good balance between the etching selectivity and the etching planar uniformity of silicon nitride relative to silicon oxide and silicon.
In particular, the present invention provides a method of plasma-etching a target substrate in a plasma etching apparatus, the target substrate having a surface on which a first layer consisting essentially of silicon nitride and a second layer consisting essentially of silicon or silicon oxide are arranged, which entails:
a) setting the etching apparatus in light of a set value of etching selectivity of the first layer relative to the second layer, and a set value of etching planar uniformity defined by a difference between sizes to be processed at a center and a periphery of the target substrate;
b) placing the target substrate in a process chamber of the etching apparatus;
c) supplying a process gas into the process chamber, while exhausting the process chamber, the process gas comprising a mixture gas of CH2F2 gas and O2 gas at a ratio of from 55% to 100% in volume percentage, the CH2F2 gas and the O2 gas being mixed at a first mixture ratio (CH2F2/O2) of from 0.2 to 0.6 in volume ratio;
d) turning the process gas into plasma by electric discharge, while keeping the process chamber at a first pressure of from 50 mTorr to 100 mTorr; and
e) etching the first layer preferentially to the second layer with the plasma; and
f) wherein parameters for the planar uniformity, by which the etching apparatus is set in light of the set value of the planar uniformity, include the first pressure and the first mixture ratio, and as the set value of the planar uniformity is more strict, either one of the first pressure and the first mixture ratio is set higher.


In order to multiply operands of different binary lengths using a common combined array, for example to do both 8 bit by 8 bit and 16 bit by 16 bit multiplications, 2.sup.m-1 multiplications are performed, where m is equal to the number of different bit lengths it is desired to multiply. For example, where 8.times.8 bit and 16.times.16 bit multiplications are done, 2 different multiplications are done. Each multiplication is an n.times.n/2.sup.m-1 multiplication, e.g., a 16.times.8 bit multiplication. Sign correction is performed by adding a correction vector or by modifying one of the partial products. The results of the multiplications are added together to obtain a 2 n bit result. Groups of bits from said 2 n result are selected depending on the length of the operands being multiplied.

This invention relates to computer multiplication in general and more particularly to an efficient combined multiplier array which can carry out multiplications on different length operands.
Various types of multipliers for use in computers have been developed. One of these types, known as a combinational array multiplier, utilizes an array including a plurality of carry save adders feeding a carry propagate adder from which the result is obtained. Such combined arrays in many instances have relied upon Booth's algorithm. See for example, Computer Architecture and Organization, 2nd Ed. by John P. Hayes, McGraw Hill, 1988, particularly pages 241-250. A detailed implementation of Booth's algorithm is described in U.K. Patent Application GB 2,262,638A, published Jun. 23, 1993, particularly in FIGS. 9-12.
The general arrangement of a specific combinational multiplier that can perform four 16.times.16 multiplications is illustrated in FIG. 1. The arrangement shown includes a first register 10 containing a first operand X comprising 64 bits and a second register 20 containing operand Y comprising 64 bits. One skilled in the art will appreciate that registers 10 and 20 can be any of a variety of other storage devices such as accumulators. Four groups of 16 of the 64 bits in register 10 provide the A, C, E, and G inputs for four 16.times.16 multipliers 15 a-d. Similarly, 16 bit groups of the register 20 (i.e., B, D, F, and H) are provided as inputs to four Booth encoders 19, and the outputs of the Booth encoders 19 are coupled as inputs to multipliers 15 a-d. Each of the multipliers generates a 32-bit output. These 32-bit outputs are used to generate the result of the multiplication of operands X and Y. As is known in the art, output shift and multiplexers (not shown specifically in FIG. 1) can be used to select the appropriate multiplier outputs for the result.
The same techniques can, of course, be utilized for multiplying larger or smaller numbers of bits. In current computers, at least 16 bit multiplications are required. In some instances, however, being able to multiply smaller numbers of bits has advantages. For example, the ability to do two 8 bit multiplications instead of a single 16 bit multiply can give significant performance advantages for low end graphics and video game applications. It can also provide a speed up for certain signal processing routines. Although it would be possible to implement 8 bit multiplies with separate 8 bit multiplier arrays, these arrays are an expensive resource. Thus, there is a need to provide an efficient combined array which can carry out both 2 n bit and n bit multiplications, e.g., where n=8. Stated another way, there is a need to have, in a processor which includes a multiplier array which can multiply a pair of 2 n bit numbers, the capability, using the same array, to also multiply two pairs of n bit numbers simultaneously.

Efficient combined array for 2n bit n bit multiplications


A safety device for a power window in which window glass of a vehicle is made to undergo an opening or closing operation by a driving motor, and which effects safety control against the nipping of a foreign object by detecting the opening and closing positions of the window glass, comprises: a position sensor for detecting the position of an angle of rotation of the driving motor; a detector the opening or closing position of the window glass based on an output of the position sensor; and a controller for effecting safety control against the nipping of the foreign object based on the detector.

The present invention relates to a power window which is used in a vehicle such as an automobile to effect the operation of opening and closing a window by a driving source such as a motor, and more particularly to a safety device which performs a safety controlling operation by detecting a state in which a passenger's hand, head, or the like is nipped between window glass and a sash.
In a power window, since the window glass is generally made to undergo opening and closing operations by a motor or the like, an accident can occur in which a passenger's hand, head, or the like is nipped between the window glass and the sash. For this reason, safety devices have been conventionally proposed for preventing an accident by detecting the state of a foreign object being nipped between the window glass and the sash, and by such as stopping the operation of opening or closing the window glass or effecting the operation of opening the window glass at that time. As such window safety devices proposed by the present applicant, various devices have been proposed including Unexamined Japanese Patent Application Publication No. Hei. 5-321530. As a safety device of this type, the motor for driving the window glass is furnished with a pulse signal oscillator comprising a Hall element, and a safety control region is determined by detecting the absolute velocity and relative velocity of the closing operation of the window glass by a detecting means on the basis of this pulse signal and by detecting the opening or closing direction by the detecting means. During the closing operation, the nipping of a foreign object is detected from at least one detection result of the absolute velocity and the relative velocity. Then, when the nipping of the foreign object is detected, safety control is effected for forcibly operating the window glass in the opening direction so as to release the foreign object from nipping by the window glass and the sash.
According to such a safety-control-region determining technique, however, since an error occurs in the determination of the safety control region due to the miscounting of the pulse signal and the like, a window-glass-position detecting mechanism such as a limit switch is newly required in the vicinity of the upper limit of the window glass. Further, as proposed in, for example, Unexamined Japanese Patent Application Publication No. Hei. 8-303113, this window-glass-position detecting mechanism requires an automatic position adjusting mechanism to omit the mounting-position adjusting operation in the assembling process in an automobile plant, so that the structure becomes complex, constituting a cause for leading to higher cost.
Accordingly, it is conceivable to determine positions for opening and closing the window by a position sensor and detect the state of the opening and closing operation of the window by means of an output from the position sensor. In this case, as the position sensor, if, for example, a potentiosensor is arranged along a rail along which the window is made to undergo the opening and closing operations, since the resistance value of the potentiosensor varies depending on the opening and closing positions of the window, it is possible to detect the opening and closing positions of the window. This arrangement, however, requires a potentiosensor of a length extending over the entire stroke of the opening and closing operation of the window, so that the structure of the vehicle window becomes complex, and it is difficult to overcome the aforementioned higher cost.


A shift device for a transmission, which comprises a sliding sleeve, a shift fork engaging in the sliding sleeve, and an actuator that can rotate on a shaft that is disposed at an angle to the transmission shaft. In order to provide a simple and reliable control that satisfies all functional requirements, a cam having two flanks and a flattened section on the maximum radius is disposed on the shaft. On the base of the shift fork, two interacting pushrods are disposed at a fixed distance so that one pushrod rests against the one flank and the other pushrod rests against the other flank and one pushrod rests against the flattened section in at least one extreme position.

The invention relates to a shift device for a transmission, consisting of a shift sleeve, displaceable in the direction of the axis of a transmission shaft, for the driving connection of transmission members, of a shift fork engaging into the shift sleeve, and of, as actuator, an element which is rotatable on a shift shaft arranged transversely to the transmission shaft and which cooperates with a foot part of the shift fork.
It is known from WO 01/59331-A to adopt, as actuator a pinion which meshes with a corresponding toothing on the foot part of the shift fork, the shift shaft being driven by an electric gear motor.
This has some disadvantages: the step-up of this movement transmission is constant, which, as a rule, does not correspond to the profile desired for shifting and to the characteristic of the electric motor; especially not when the shift sleeve has synchronization. There are no stops, and the toothing has no blocking action, that is to say it cannot retain the shift sleeve in the respective position. Both factors, however, are particularly important in the case of an electromotive drive. The motor is, of course, to remain currentless after a completed changeover and is even to be capable of being uncoupled in specific applications, even when changeover took place counter to the ever-acting force of a spring. Furthermore, to simplify the control, the motor is to be capable of being moved up against a stop, in order to manage without position or speed sensors.
In order to remedy this, the object of WO 01/59331-A is to provide a detent disk firmly connected to the rotating element and a detent member engaging into a detent recess. Said detent member holds the rotating element after the uncoupling of the electric motor and ensures that this is possible only after a defined end position is reached. However, this remedy is highly complicated and is also not entirely satisfactory in functional terms. Due to the moments acting on the element and consequently on the detent disk (which emanate, for example, from the synchronization or from chamfers of the teeth in order to secure the sleeve against a stop), friction arises which obstructs or completely prevents the changeover. This may also occur when the two elements to be coupled are in an unfavorable relative position. The other gear in each case then cannot be engaged, and the sleeve remains set in the neutral position, which may lead to hazardous driving situations and therefore should not happen. Moreover, due to the long tolerance chain, positioning is inaccurate.
The object of the invention, therefore, is to propose a simple and reliable control which satisfies all functional requirements, in particular safety requirements.

Shift device for a transmission and power divider of a motor vehicle having such a shift device


The present invention relates to a non-immunostimulatory antibody which lacks antibody-dependent cell-mediated cytotoxicity, Fc gamma receptor binding and complement-mediated cytotoxicity. In some embodiments, the antibody contains a modified immunoglobulin G2 (IgG2) Fc region with at least one substitution in the B/C loop, FcRn binding domain, and the F/G loop. The antibody of the invention is useful in the preparation of therapeutic antibodies and pharmaceutical compositions and kits containing the same.

Antibodies are proteins which exhibit binding specificity to a specific antigen. Native antibodies are usually heterotetrameric glycoproteins composed of two identical light (L) chains and two identical heavy (H) chains. Each light chain is linked to a heavy chain by one covalent disulfide bond, while the number of disulfide linkages varies between the heavy chains of different immunoglobulin isotypes. Each heavy and light chain also has regularly spaced intrachain disulfide bridges. Each heavy and light chain has at one end a variable domain (VH and VL) followed by a number of constant domains. The variable domains differ extensively in sequence among antibodies and are responsible for the binding specificity of each particular antibody for its particular antigen. However, the variability is not evenly distributed through the variable domains of antibodies. It is concentrated in three complementarity determining regions (CDRs) both in the light chain and the heavy chain variable domains. The CDRs in each chain are held together in close proximity by the framework regions and, with the CDRs from the other chain, contribute to the formation of the antigen binding site of antibodies (Kabat, et al. (1991) Sequences of Proteins of Immunological Interest, 5th Ed. Public Health Service, National Institutes of Health, Bethesda, Md).
The constant domains are not involved directly in binding an antibody to an antigen, but exhibit various effector functions. Depending on the amino acid sequence of the constant region of their heavy chains, antibodies or immunoglobulins can be assigned to different classes. There are five major classes of immunoglobulins: IgA, IgD, IgE, IgG and IgM, and in humans several of these are further divided into subclasses (isotypes), e.g., IgG1, IgG2, IgG3, and IgG4; IgA1 and IgA2. The human IgG isotypes, IgG1, IgG2, IgG3, and IgG4 elicit differential responses due to their sequence differences, which result in differential binding the to Fcγ receptors (Daeron (1997) Annu. Rev. Immunol. 15:203-234) and/or the initial complement component, C1q (Cooper (1985) Adv. Immunol. 37:151). Of the various human immunoglobulin classes, only human IgG1, IgG2, IgG3 and IgM are known to activate complement; and human IgG1 and IgG3 mediate ADCC more effectively than IgG2 and IgG4.
Papain digestion of antibodies produces two identical antigen binding fragments, called Fab fragments, each with a single antigen binding site, and a residual Fc fragment, whose name reflects its ability to crystallize readily. The crystal structure of the human IgG Fc region has been determined (Deisenhofer (1981) Biochemistry 20:2361-2370). In human IgG molecules, the Fc region is generated by papain cleavage N-terminal to Cys 226. The Fc region is central to the effector functions of antibodies.
The effector functions mediated by the antibody Fc region can be divided into two categories, namely effector functions that operate after the binding of antibody to an antigen (these functions involve the participation of the complement cascade or Fc receptor (FcR)-bearing cells); and effector functions that operate independently of antigen binding (these functions confer persistence in the circulation and the ability to be transferred across cellular barriers by transcytosis) (Ward and Ghetie (1995) Therapeutic Immunology 2:77-94).
The interaction of antibodies and antibody-antigen complexes with cells of the immune system effects a variety of responses, including antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-mediated cytotoxicity (CMC) (see Daeron (1997) Annu. Rev. Immunol. 15:203-234; Ward and Ghetie (1995) supra; Ravetch and Kinet (1991) Annu. Rev. Immunol. 9:457-492).
Several antibody effector functions are mediated by Fc receptors (FcRs), which bind the Fc region of an antibody. FcRs are defined by their specificity for immunoglobulin isotypes; Fc receptors for IgG antibodies are referred to as FcγR, IgE for FcεR, etc. Three subclasses of FcγR have been identified, FcγRI (CD64), FcγRII (CD32) and FcγRIII (CD16). It is known, for example, that IgG1 and IgG3 isotypes bind FcγRI with a Kd of approximately 109 M−1 (Canfield and Morrison (1991) J. Exp. Med. 173:1483-1491), but that the IgG4 isotype binds approximately 10-fold less affinity, and IgG2 isotype has an affinity for FcγRI more than 1000-fold greater (e.g., at least 106 M1; Canfield and Morrison (1991) supra). Another type of Fc receptor is the neonatal Fc receptor (FcRn). FcRn is structurally similar to major histocompatibility complex (MHC) and is composed of an α-chain noncovalently bound to β2-microglobulin. FcRn binds IgGs, internalizes them into endocytic vesicles, and then, through a pH-dependent step, recycles the antibodies back into the serum (Ghetie and Ward (2000) Annu. Rev. Immunol. 18:739-766). This process effectively increases the half-life of IgGs and gives them their nominal half-lives in serum of about 20 days (Ghetie and Ward (2000) supra).
C1q and two serine proteases, C1r and C1s, form the complex C1, the first component of the complement-dependent cytotoxicity (CDC) pathway. To activate the complement cascade, it is necessary for C1q to bind to at least two molecules of IgG1, IgG2, or IgG3, but only one molecule of IgM, attached to the antigenic target (Ward and Ghetie (1995) supra). Based upon the results of chemical modifications and crystallographic studies, the binding site for the complement subcomponent C1q on IgG has been suggested to involve the last two (C-terminal) β-strands of the CH2 domain (Burton, et al. (1980) Nature 288:338-344), with amino acid residues 318 to 337 involved in complement fixation (Burton, et al. (1985) Mol. Immunol. 22(3):161-206).
Key residues of the various IgG isotypes involved in binding to FcRs and C1q have been suggested. The binding site on human and murine antibodies for FcγR have been mapped to the lower hinge region composed of residues 233-239 (numbering as in Kabat, et al. (1991) supra; Woof, et al. (1986) Mol. Immunol. 23:319-330; Duncan, et al. (1988) Nature 332:563; Canfield and Morrison (1991) J. Exp. Med. 173:1483-1491; Chappel, et al. (1991) Proc. Natl. Acad. Sci USA 88:9036-9040). Of residues 233-239, P238 and S239 have been cited as possibly being involved in binding. Other previously cited areas possibly involved in binding to FcγR include G316-K338 (human IgG) for human FcγRI (Woof, et al. (1986) supra); K274-R301 (human IgG1) for human FcγRIII (based on peptides) (Sarmay, et al. (1984) Mol. Immunol. 21:43-51); Y407-R416 (human IgG) for human FcγRIII (based on peptides) (Gergely, et al. (1984) Biochem. Soc. Trans. 12:739-743); as well as N297 and E318 (murine IgG2b) for murine FcγRII (Lund, et al. (1992) Mol. Immunol. 29:53-59). Peptide analysis of IgG1 demonstrates significant binding of residues 256-271 to FcγRIIb (Medgyesi, et al. (2004) Eur. J. Immunol. 34:1127-1135).
Armour, et al. ((1999) Eur. J. Immunol. 29:2613) further suggest the role of residues 230-236 in FcγRI binding. IgG2-like lower hinge regions and mutations at residues G327, S330, and S331 were inactive in binding FcγR as well as in complement-mediated cell lysis. Additional analysis of an IgG2 mutant with point mutations A230S and P231S, indicated reduced binding to the 131H polymorphism of FcγRIIa as compared to IgG2 and approximately equal binding to the 131R polymorphism of FcγRIIa as compared to IgG2. Moreover, this IgG2 mutant favored binding to the FcγRIIb inhibitory receptor. See also, WO 99/58572. A hybrid IgG2/IgG4 antibody, composed of IgG2 CH1 and hinge region fused to IgG4 at about residue P238, has also been disclosed which lacks binding to U937 cells which possess FcγRI (WO 97/11971).
Duncan and Winter (Nature 332:738-40 (1988)), using site-directed mutagenesis, reported that Glu318, Lys320 and Lys322 form the binding site for the murine C1q. The key role of these residues was further suggested by Thommesen, et al. ((2000) Mol. Immunol. 37:995-1004) and in U.S. Pat. Nos. 5,648,260 and 5,624,821. However, it was subsequently shown that these residues are not the same residues in human antibody binding to C1q. Alanine substitutions at positions D270A, K322A, P329A, and P331G of IgG1 have also been demonstrated to significantly reduce C1q binding and complement activation (Idusogie, et al. (2000) J. Immunol. 164:4178-4184).
Residue Pro331 has been implicated in C1q binding by analysis of the ability of human IgG subclasses to carry out complement-mediated cell lysis. Domain swapping between IgG2 and IgG3, as well as IgG1 and IgG4 has been used to dissect the function of residues 292-340, with mutations A330S and P331S eliminating C1q binding and mutation P331S reducing binding to FcγRI (Tao, et al. (1991) J. Exp. Med. 173:1025-1028; Canfield and Morrison (1991) supra; Greenwood, et al. (1993) Eur. J. Immunol. 23:1098-1104). The significance of A330 and P331 was also disclosed by Shields, et al. ((2001) J. Biol. Chem. 276:6591-6604) and in U.S. Pat. No. 6,737,056 and U.S. patent application Ser. No. 11/194,989. Site-directed mutation of P331S in IgG1 (Xu, et al. (1994) J. Biol. Chem. 269:3469-3474) and S331P in IgG4 (Brekke, et al. (1994) Eur. J. Immunol. 24:2542-2547) further suggested the key role of this residue in C1q binding and complement activation. Other reports suggest that human IgG1 residues Leu235, and Gly237, located in the lower hinge region, play a critical role in complement fixation and activation (Xu, et al. (1993) J. Immunol. 150:152A). Amino acid residues 231 to 238 have also been suggested to be necessary for C1q and FcR binding of human IgG1 (WO 94/29351).
Therapeutic antibodies for the treatment of a variety of diseases are known in the art. It is desirable that these antibodies do not provoke an immune reaction toward cells harboring the target antigen. Therefore, there is a need in the art for the generation of therapeutic human or humanized monoclonal antibodies that do not possess any effector functionality, yet retain the typical pharmacookinetics of an IgG. The present invention meets this need in the art.

Non-immunostimulatory antibody and compositions containing the same


A cargo bin formed of a medial cargo module having opposing open ends formed to securely engage an extension member to extend the length of the bin, or an end wall, for use when a non-extended bin is required. A unique engagement mechanism is provided for securely affixing the extension member or end wall to the medial cargo module, wherein there is provided a cradle formed to receive an engagement rod, the engagement mechanism formed to securely guide the components together so as to align engagement apertures associated with the side edges of the units, which engagement apertures, when aligned, are secured via retention pins or the like.

Cargo bins, tool baskets or the like are commonly used in servicing the oil industry to convey materials, tools, and supplies to rigs or the like. Crew boats and drilling rigs have very limited space, so it is important that the cargo bin take only as much space as is required to securely and safely convey the contents. As there are a varied array of possible configurations for the items being transported, it is also advantageous to be able to modify a cargo bin to accommodate the various cargo, so as to maximize flexibility of use.
In the past, cargo bins or the like have been designed with knock down walls to make the unit collapsible for enhanced storage. See for example U.S. Pat. No. 6,752,285.
Other cargo bins have been formed so as to be able to be joined into a single, extended unit, such as that shown in the cargo containers of U.S. Pat. No. 3,061,134.
Published patent applications US2005/0058532 and 2006/0032850 teach extendable shipping baskets or the like wherein extended end units engage a central modular unit in socketed fashion, via a pair of upper and lower extension pieces which require relatively precise alignment and simultaneous positioning to engage the unit, which could prove problematic in view of the substantial weight and size of these units.

Extendable cargo system and method therefore


A shear-extrusion method of severe plastic deformation for fabrication of metal shapes with ultra-fine structures is described. The improvements of the method include unidirectional shear of any required intensity during one step processing and under high hydrostatic pressures, fabrication of long products with different cross-sections, refinement of low ductile alloys, the increase of productivity and cost reduction. The method can be realized as forward extrusion, backward extrusion, semi continuous extrusion and extrusion of hollow shapes in portal dies with a welding chamber.

1. Field of the Invention
The present invention relates to severe plastic deformation of metals and alloys to control their structure and properties.
2. Description of the Prior Art
It is known in the art that severe plastic deformation performed by simple shear results in refinement of grain structures to the sub-micron, sometimes to nano scale. That leads to significant improvements in many physical and mechanical properties such as strength, ductility, fatigue, corrosion resistance, super plasticity, etc. Different processing methods were developed for intensive plastic deformation. Most of them are restricted by small sample sizes or soft materials and are used as a laboratory tool: high pressure torsion (P. W. Bridgeman, Studies in Large Plastic Flow and Fracture, McGrill, New York, 1952), cyclic extrusion-compression (A. Korbel, M. Richert, J. Richert, in: Second RISO International Symposium on Metallurgical Science, 1981, p. 485), repetitive corrugation and straightening (U.S. Pat. No. 6,197,129). Some techniques allow processing of sufficiently large billets and have potentials for industrial applications: equal channel angular extrusion (ECAE) (Invention Certificate of the USSR No 575892, 1974), accumulative roll-bonding (Y. Saito, N. Tsuji, H. Utsonomiya, T. Sakai and R. G. Hong, "Scripta Materialia", 39, 1998, p. 1221), twist-extrusion (J. Beigelzimer, D. Orlov and V. Varyhin, in: "Ultrafine Grained Materials-II", 2002, p. 297) and multi-directional forging (U.S. Pat. No. 6,422,090). Equal channel angular extrusion is considered the most promising candidate for practical applications and was used in many patents (see U.S. Pat. Nos. 5,400,633; 5,513,512; 5,600,989; 5,826,456; 5,850,755; 5,904,062). However, all these techniques are characterized by a few important disadvantages. As effective strains per pass are usually less than ε≦1 whereas accumulated strains for structure refinement ranges from ε=6 to ε=12, a large number of processing steps or passes should be used. Each pass requires billet preparation, preheating and lubrication. In result, such processing is time and labor consuming with a high product cost. Also, only simple billet shapes like short bars, rods or plates can be fabricated. In most cases, their conversion to final products presents additional problems with the increase in the cost. Therefore, these techniques are effective only for special applications. For example, the only reported commercialization of equal channel angular extrusion relates to sputtering targets in electronic and semiconductor industries (U.S. Pat. Nos. 5,590,389; 6,569,270).
It is very desirable to develop a cost effective industrial method for fabrication of complicated shapes like long extrusions with ultra-fine grained structures. These products may have numerous applications as structural materials in automotive, transportation, aero-space and other industries. However, the only known method in the art for such products is superplastic extrusion (see U.S. Pat. No. 5,620,537). This method comprises two step processing: (i) equal channel angular extrusion to prepare ultra-fine structures and (ii) superplastic extrusion. The first step conserves the above mentioned disadvantages of multi-pass ECAE. The second step should be realized with very low strain rates or high temperatures that leads to low productivity and degradation of the material structure and properties. Therefore, the known method does not provide evident technical benefits and did not find practical applications. The present invention is intended to resolve all these and other problems.


A circuit for driving the voltage of a capacitive element between two voltage levels has at least one driver cell with a first pair of switches connected in series between a first terminal of a voltage source and the capacitive element, and a second pair of switches connected in series between a second terminal of the voltage source and the capacitive element. One or more non-dissipative elements may be connected between the common node of the first pair of switches and the common node of the second pair of switches. Combinations of switches from the driver cells may be activated and deactivated in a defined sequence to provide step-wise transfer of energy to the capacitive element. In one sequence, switches in a selected driver cell may subtract a specified voltage from an input voltage, bypass the selected driver cell, and add the specified voltage to the input voltage.

This invention relates to methods and systems for driving the voltage of a capacitive element between two voltage levels such as ground and supply voltage. Non-dissipative elements such as capacitors may be used to improve the energy efficiency of capacitive element driving.
The control of an electronic or electrical device is normally performed by applying a voltage at its control terminal, for example, to activate or deactivate the device. The control terminal may be the control gate of a transistor of any type, including but not limited to a Metal Oxide Semiconductor Field Effect Transistor (MOSFET), a Gallium Nitride Field Effect Transistor (GaN-FET), a Silicon Carbide Field Effect Transistor (SiC-FET), a Junction Field Effect Transistor (JFET), or an Insulated Gate Bipolar Transistor (IGBT). The control terminal may also be a control input of another sort of electronic or electrical device, including but not limited to an electrostatic actuator or other systems such as micro motors, micro mirrors, and micro switches based on Micro-Electro-Mechanical Systems (MEMS) technology, memory and logic circuits based on multiferroic/magnetoelectric materials, ultrasonic transducers, piezoelectric actuators, electronic paper displays (E-paper), and actuators based on electroactive polymers.
In an electronic or electrical system in which devices have control terminals with capacitive elements, drivers are used to drive the voltage of those control terminals between two voltage levels to activate or deactivate those devices. Systems employing drivers include switch mode power converters, motor drivers, electrostatic actuators, electroactive polymer actuators, and multiferroic/magnetoelectric devices. Periodic switching is helpful in maintaining the average voltage of those storage capacitors at an unchanged level.
In conventional methods of capacitive element driving, a circuit 100 such as shown in FIG. 1A, with the operation of circuit 100 shown in the waveforms of FIG. 1B, may have two switches, SW1[1], SW1[2], with switch SW1[1] connected between the capacitive element CO1 and one terminal of the voltage source VDD1 and with switch SW1[2] connected between the capacitive element CO1 and another terminal of the voltage source VDD1, which are switched on and off alternately to drive the voltage of the capacitive element CO1 between two levels (e.g. 0V and VDD1). However, such driving methods are not energy efficient.
The waveforms of FIG. 1B show the operation of the circuit 100, in which, when the capacitive element voltage (VO1) is driven from ground (or supply voltage) to the driving circuit's supply voltage (or ground), transient current flows through the switch SW1[1] (or SW1[2]) until the voltage VO1 is settled. Then energy ECAP1=½CO1VDD12 is stored in (or taken away from) the capacitive element CO1. When transient current ISW1[1] (or ISW1[2]) flows through switch SW1[1] (or SW1[2]), a voltage difference appears across the switch and energy is absorbed. Switch SW1[1] (or SW1[2]) is a dissipative element, so that the absorbed energy (EDISS1=½CO1VDD12) is dissipated. The energy loss per driving cycle (ELOSS1) is CVDD12.
One method for avoiding energy dissipation of circuit 100 is to introduce a resonant capacitive element driver in which an inductor is added to the input of a capacitive element, and to periodically drive capacitive elements between two voltage levels. One circuit 200 for resonant capacitive element driving is shown in FIG. 2A, with the operation of circuit 200 shown in the waveforms of FIG. 2B.
As shown in FIG. 2A, switches SW2[1] and SW2[2] are connected in series between the terminals of the voltage source VDD2, diodes D2[1] and D2[4] are also connected in series between the terminals of the voltage source VDD2, and diodes D2[3] and D2[2] are also connected in series between the terminals of the voltage source VDD2. Switch SW2[1], diode D2[4], and diode D2[2] share a common node 202, which is electrically connected to the positive terminal of the voltage source VDD2. Switch SW2[2], diode D2[1], and diode D2[3] share a common node 204, which is electrically connected to the negative terminal of the voltage source VDD2; and switch SW2[1], SW2[2], diode D2[4], and diode D2[1] share a common node 206. An inductor L2 may be disposed between the common-node 206 and a common node 208 shared by the diodes D2[2] and D2[3] and the capacitive element CO2.
In operation, the circuit 200 stores the energy EDISS2 in the inductor L2. The use of a non-dissipative element such as the inductor L2 in circuit 200 allows energy to be stored in the non-dissipative element instead of dissipated as heat on resistive element. Diodes D2[1] and D2[2] (or D2[3] and D2[4]) may transfer the stored energy EDISS2 back to the voltage source VDD2 after the capacitive element voltage VO2 is driven from ground to the driving circuit's supply voltage VDD2 (or from supply voltage VDD2 to ground).
Therefore, the inclusion of the inductor L2 into the circuit 200 reduces the dissipation of energy, storing ECAP2=½CO2VDD22 in the non-dissipative element, thus rendering the circuit 200 more energy efficient. However, there is a tradeoff between ramp rate of VO2 and peak inductor current. The inductor L2 and capacitive element CO2 form a resonant network, which has its resonant period and characteristic impedance proportional to the value of the square root of L2. To increase the VO2 ramp rate, an inductor with a smaller value than the inductor L2 may be used, but its substitution into circuit 200 also introduces a higher peak inductor current. Also, the inclusion of an additional element (inductor L2) in circuit 200 introduces extra current and hence conduction loss due to resonant behaviour, rendering the circuit 200 bulky and costly.
A network with a capacitor and inductor may also be used as a resonant capacitive element driver in circuits designed to avoid dissipation energy. One circuit 300 for resonant capacitive element driving using an LC network is shown in FIG. 3A, with the operation of circuit 300 shown in the waveforms of FIG. 3B.
As shown in FIG. 3A, an inductor and a capacitor (LC) network LC3 is inserted between common-node 310 of switches SW3[1] and SW3[2], and ground. Energy ECAP3 may be transferred from the capacitive element CO3 to the LC network LC3 once voltage VO3 is changed from supply voltage VDD3to ground; and transferred back from the LC network LC3 to the capacitive element CO3 when voltage VO3 changes from ground to the driving circuit's supply voltage.
As with circuit 200, while the LC network LC3 incorporated into the circuit 300 renders the circuit 300 more energy efficient because it prevents dissipation of energy ECAP3=½CO3VDD32 stored in the capacitive element CO3, the tradeoff between ramp rate of VO2 and peak inductor current still exists in the circuit 300. Further, the additional element (LC network LC3) still introduces extra current and hence conduction loss due to resonant behaviour into the circuit 300, rendering the circuit 300 even more bulky and costly than circuit 200.
It is desirable to have simple, convenient, energy-efficient methods, circuits, and systems for driving systems employing capacitive elements. It is desirable to have simple, convenient, energy-efficient methods, circuits, and systems for driving capacitive elements that simply and efficiently store energy in at least one non-dissipative element, that transfer the energy to drive a capacitive element between two voltage levels, and that may transfer the energy in a series of steps. Further, it may be desirable to develop simple, convenient, energy-efficient methods, circuits, and systems for driving capacitive elements in which energy may be transferred from non-dissipative elements while an average voltage level value for the non-dissipative element is maintained unchanged over time.

Non-dissipative element-enabled capacitive element driving


The invention relates to fuel cell systems and associated methods of operation where an electrochemical cell such as a fuel cell is used as an electrochemical hydrogen separator to separate hydrogen from a process stream (e.g., reformate or synthesis gas), or as an electrochemical hydrogen expander to inject hydrogen into a process stream. In one aspect, the invention provides a method of operating a fuel cell system, including the following steps: flowing hydrogen from a hydrogen supply conduit through a fuel cell to provide an electric current to a load coupled to the fuel cell; actuating an electrochemical hydrogen separator in a first mode of operation of the system to transfer hydrogen from the hydrogen supply conduit to a hydrogen storage vessel; and actuating an electrochemical hydrogen expander in a second mode of operation of the system to transfer hydrogen from the hydrogen storage vessel to the fuel cell.

The invention relates to fuel cell systems and associated methods of operation where an electrochemical cell such as a fuel cell is used as an electrochemical hydrogen separator to separate hydrogen from a process stream, or as an electrochemical hydrogen expander to inject hydrogen into a process stream.
A fuel cell is an electrochemical device that converts chemical energy produced by a reaction directly into electrical energy. For example, one type of fuel cell includes a polymer electrolyte membrane (PEM), often called a proton exchange membrane, that permits only protons to pass between an anode and a cathode of the fuel cell. At the anode, diatomic hydrogen (a fuel) is reacted to produce protons that pass through the PEM. The electrons produced by this reaction travel through circuitry that is external to the fuel cell to form an electrical current. At the cathode, oxygen is reduced and reacts with the protons to form water. The anodic and cathodic reactions are described by the following equations:H2→2H++2e−  (1)at the anode of the cell, andO2+4H++4e−→2H2O  (2)at the cathode of the cell.
A typical fuel cell has a terminal voltage of up to about one volt DC. For purposes of producing much larger voltages, multiple fuel cells may be assembled together to form an arrangement called a fuel cell stack, an arrangement in which the fuel cells are electrically coupled together in series to form a larger DC voltage (a voltage near 100 volts DC, for example) and to provide more power.
The fuel cell stack may include flow field plates (graphite composite or metal plates, as examples) that are stacked one on top of the other. The plates may include various surface flow field channels and orifices to, as examples, route the reactants and products through the fuel cell stack. A PEM is sandwiched between each anode and cathode flow field plate. Electrically conductive gas diffusion layers (GDLs) may be located on each side of each PEM to act as a gas diffusion media and in some cases to provide a support for the fuel cell catalysts. In this manner, reactant gases from each side of the PEM may pass along the flow field channels and diffuse through the GDLs to reach the PEM. The PEM and its adjacent pair of catalyst layers are often referred to as a membrane electrode assembly (MEA). An MEA sandwiched by adjacent GDL layers is often referred to as a membrane electrode unit (MEU).
A fuel cell system may include a fuel processor that converts a hydrocarbon (natural gas or propane, as examples) into a fuel flow for the fuel cell stack. For a given output power of the fuel cell stack, the fuel flow to the stack must satisfy the appropriate stoichiometric ratios governed by the equations listed above. Thus, a controller of the fuel cell system may monitor the output power of the stack and based on the monitored output power, estimate the fuel flow to satisfy the appropriate stoichiometric ratios. In this manner, the controller regulates the fuel processor to produce this flow, and in response to the controller detecting a change in the output power, the controller estimates a new rate of fuel flow and controls the fuel processor accordingly.
A fuel cell may also operate on pure hydrogen or other streams containing hydrogen such as synthesis gas. In some cases, especially at operating temperatures lower than 100° C., carbon monoxide may poison fuel cell catalysts (e.g., platinum), so it may be desired to remove carbon monoxide from such a stream (e.g., to less than 50 parts per million) before flowing it through a fuel cell. Some fuel cell membrane materials such as the polybenzimidazole membrane available from Celanese operate at higher temperatures (e.g., greater than 120° C.), so that carbon monoxide is less of a concern in this respect. Direct methanol fuel cells are also known that can react methanol directly to achieve proton exchange through the fuel cell membrane.
The fuel cell system may provide power to a load, such as a load that is formed from residential appliances and electrical devices that may be selectively turned on and off to vary the power that is demanded by the load. Thus, the load may not be constant, but rather the power that is consumed by the load may vary over time and abruptly change in steps. For example, if the fuel cell system provides power to a house, different appliances/electrical devices of the house may be turned on and off at different times to cause the load to vary in a stepwise fashion over time. Fuel cell systems adapted to accommodate variable loads are sometimes referred to as "load following" systems.
There is a continuing need for integrated fuel cell systems and associated process designed to achieve objectives including the forgoing in a robust, cost-effective manner.

This patent is subject to a terminal disclaimer.

Method and apparatus for electrochemical compression and expansion of hydrogen in a fuel cell system


A method for shrinkage of collagen tissue by application of coherent infrared energy, in which the threshold shrinkage temperature is substantially reduced by application of a reagent such as lysozyme to the tissue prior to heating. The method is especially useful in ophthalmology for shape modification of a cornea, and is enhanced by using a corneal collagen shield as a carrier and delivery agent for the reagent and an admixed anaesthetic.

My U.S. patent application Ser. No. 07/546,252 and U.S. Pat. No. 4,976,709, the entire disclosures of which are incorporated herein by reference, describe methods and apparatus for achieving controlled shrinkage of collagen tissue. These prior inventions have application to collagen shrinkage in many parts of the body, and are particularly useful in an ophthalmological procedure for achieving controlled shape changes in the cornea of the eye for correction of refractive errors.
As described in detail in the application and patent which are incorporated by reference, a presently preferred collagen-shrinkage technique involves use of laser coherent energy in a wavelength range of about 1.80 to about 2.55 microns, or of such coherent infrared energy of wavelengths corresponding to collagen absorption coefficients in the range of about 15 to 120 cm.sup.-1. Irradiation of collagen with such energy is controlled to elevate the collagen temperature to at least 23.degree. C. above normal body temperature to achieve collagen shrinkage.
As explained in my referenced prior disclosures, a critical factor in shrinkage of corneal collagen of the eye is avoidance of excessive tissue-destructive temperature increases throughout the corneal stroma, and especially in the outer epithelial and inner endothelial layers of the cornea. A lowering of the threshold temperature at which collagen shrinkage occurs will provide an added measure of safety in avoiding tissue-destructive temperature increases, and it is to this goal that the present invention is directed.


A vertical can be a series of computer-executable instructions that, in response to an incident, collect information regarding that incident and transmit the information for analysis and possible helpful feedback to the user. A general purpose vertical can address types of incidents, such as crashes or hangs, across a variety of applications, while a custom vertical can be written to address application-specific incidents. Verticals can access underlying support mechanisms through an infrastructure, which can also enable applications to request that additional data be collected by the verticals, and set other preferences. Once the data is collected and transmitted, a vertical may receive feedback, that can be a request for additional information or feedback to the user. The feedback to the user can attempt to identify the incident and aid the user in recovering from it and avoiding it in the future.

All too frequently application programs experience incidents which result in the loss of information, forcing users to perform the frustrating and inefficient task of re-entering all of the lost information into the application program. Additional inefficiency is created by the need to restart the application program or even the computing device itself in an attempt to recover from the incident, or to attempt to prevent further incidents. Unfortunately, the vast majority of users are ill equipped to determine why the incident occurred, and are therefore generally powerless to prevent its reoccurrence.
The programmers of the application programs, and others tasked with supporting the programs after their release, are often in a worse position to assess the causes of various incidents because users either cannot adequately describe the circumstances under which those incidents occurred, or do not even bother to report them. Consequently, many programmers and application support personnel are not even aware of the majority of such incidents and, of those incidents of which they are aware, they do not possess sufficient information upon which to provide useful feedback. Additionally, because many users do not bother to report such incidents, the application support personnel often underestimate the existence of the applications' faults, or receive an insufficient quantity of user reports from which to detect similarities among the incidents and thereby attempt to resolve them.
To address such shortcomings, modern operating systems have recently begun to incorporate a rudimentary incident reporting mechanism by which a small, pre-selected amount of data is saved when an incident occurs, and then subsequently data is transmitted to a central repository which can be accessed by programmers and other support personnel so that they may attempt to ascertain a cause, and provide a solution to prevent further incidents. Unfortunately, such incident reporting mechanisms are often too general to provide useful information regarding the incidents of particular applications. For example, an incident reporting mechanism that detects an application incident where the application stops responding, commonly referred to as a "hang", may collect data from an area of memory that the operating system believes is most relevant. However, the programmers and support personnel of that particular application may not learn anything useful from the saved data, and might have preferred to save a different collection of data, which may have provided more useful information. Of course, the above assumes that the programmers and support personnel of that particular application would even seek to obtain the data collected by the operating system. Generally, such information is reported to the support personnel supporting the operating system, and there may exist inefficiencies of communication between the operating system support personnel and the application support personnel.
Therefore, what is needed is a mechanism by which application developers, programmers and support personnel can specify which information is collected from their applications in the case of particular incidents. In addition, the developers and programmers should be provided with default mechanisms which can collect a minimum of information to record those incidents that may not have been foreseen by the developers and programmers of the application, or which may be the result of an interaction between the applications of two or more different groups of developers and programmers.

Method and system for an incidental feedback platform


An oil composition comprises at least 50 percent by mass, based on the mass of the composition, of an oil and 0.01 to 25 percent by mass, based on the mass of the composition, of a polymer comprising at least one poly(lactone) segment. The at least one poly(lactone) segment is derived from a lactone substituted by one or two hydrocarbyl groups, or substituted hydrocarbyl groups, at least one such group having at least 4 carbon atoms. The oil compositions are suitable for use in the lubrication of the crankcase of internal combustion engines.

There is much interest in improving the fuel economy of gasoline and diesel engines. This can be done, through the engine lubricating oil, by reducing the friction contribution either of the bulk fluid (by lowering the oil viscosity) or improving the friction of the contacting parts by inclusion of friction modifier additives. Oil compositions used for purposes other than engine lubrication may also benefit from reduced friction.
There is therefore interest in additives which provide oils with low friction properties.
It is also important that additives used in oils have good solubility, in order for the oils to remain stable under prolonged storage.
Polymers derived from lactone monomers, poly(lactones), are known in the art. Numerous studies Poly(lactones) have found use in the formation of various coatings plastics, and fibres. Many lactones and poly(lactones) are biocompatible and a range can be made from naturally occurring compounds. Accordingly, poly(lactones) have been disclosed for medical applications. For example, WO20181142384 A2 describes how co-polymers formed from lactone and poly(propylene fumarate) can be used as feeds in additive manufacturing (3D printing) to produce medical devices and structures for in-vivo application. Poly(lactones) are commonly formed via ring-opening polymerisation (ROP).
The present invention is based on polymers which contain at least one polymeric segment which is derived from a lactone substituted by a group of a certain minimum carbon chain length. It has been found that the presence of this polymeric segment provides the polymers with beneficial properties when used as additives in oil compositions. In the polymer art, crystallisation driven self-assembly (CDSA) has become a powerful tool for the preparation of nanostructures with well-defined dimensions. Polymers having a solvophobic core block can undergo CDSA to yield various nanostructures, driven by the crystallisation behaviour of the core polymer block. These can take the form of spherical micelles, wormlike cylinders, rods, and platelets of various morphologies. Owing to their backbone and hydrophobic properties, poly(lactones) are good candidates for CDSA and it is presently theorized that the various nanostructures obtainable via CDSA contribute to the effectiveness of the polymers as additives when used in oil compositions, including lubricating oil compositions.


There is disclosed a digital camera which detects a focus of a lens unit by a method selected from a plurality of focus detection methods based on information on the lens unit taken from the lens unit attached to the digital camera. As an example of a focus detection method, there is a method by a phase difference system or a contrast system, but the method is not limited to this example.

1. Field of the Invention
The present invention relates to a digital camera and a camera system having an automatic focusing (AF) control function.
2. Description of the Related Art
Heretofore, as an AF mechanism disposed in a single-lens reflex camera using a film and a single-lens reflex digital camera, a through-the-lens (TTL) phase-difference AF mechanism has been frequently used. In this case, a defocus detection mechanism which performs the TTL phase-difference AF is disposed in a main body of the single-lens reflex camera. Moreover, a focusing lens disposed in a lens barrel of an interchangeable lens which is detachably attached to the single-lens reflex cameras is driven by a motor disposed in the lens barrel of the interchangeable lens or the main body of the single-lens reflex camera to perform a focusing control operation. It is to be noted that the TTL phase-difference AF is sometimes referred to simply as the phase-difference AF.
On the other hand, in a compact digital camera, a camcorder or the like, so-called imager AF is frequently performed which is AF of such a system that contrast is detected with a high frequency component of a signal of an image pickup device. Here, the imager AF is an auto focusing method where an evaluated focal value of a focus lens at each focus lens position is calculated while moving the focus lens at a predetermined driving amount interval, and the focus lens position where the evaluated focal value reaches a peak value is obtained.
It is to be noted that the TTL phase-difference AF and the imager AF have the following characteristics, respectively.
The TTL phase-difference AF is the AF at a speed higher than that of the imager AF.
The imager AF is the AF having a precision higher than that of the TTL phase-difference AF.
Based on such characteristics, the TTL phase-difference AF and the imager AF are selectively used in accordance with an application. Here, as a technology in selectively using the TTL phase-difference AF and the imager AF, for example, the following technology is known.
In Japanese Patent Application Laid-Open No. 7-43605, an automatic focusing device is disclosed in which the TTL phase-difference AF is combined with the imager AF to perform focusing control. Specifically, in this automatic focusing device, after coarse control is performed by the TTL phase-difference AF, fine control is performed by the imager AF.
Moreover, in Japanese Patent Application Laid-Open No. 2003-302571, an automatic focusing control device is also disclosed in which after the coarse control is performed by the TTL phase-difference AF, the fine control is performed by the imager AF in the same manner as in the automatic focusing device disclosed in Japanese Patent Application Laid-Open No. 7-43605. However, in this automatic focusing control device disclosed in Japanese Patent Application Laid-Open No. 2003-302571, to speed us the focusing, the TTL phase-difference AF is selected in preference to the imager AF, when it is decided that the focusing is possible with the TTL phase-difference AF alone.
In addition, for a lens-interchangeable single-lens reflex camera using a film, many interchangeable lenses are on sale and already spread widely. Here, many of the interchangeable lenses which have already spread are designed to perform the TTL phase-difference AF. That is, focusing control mechanisms and the like of the focus lenses disposed in the lens barrels of many interchangeable lenses are designed as a system which drives the lens by a driving amount corresponding to a detected defocus amount. Specifically, as a driving source for the focusing control in the interchangeable lens barrel, a direct-current motor (a DC motor) is employed in many cases. On the other hand, as the driving source of the focus lens in the imager AF, a stepping motor is optimum. In actual, stepping motors are employed in many cases of the imager AF.


A snow plow blade with integrated multiple horizontal slats in lieu of one solid curved blade comprises a plurality of thin blades stacked upon one another in a staggered retreating arrangement from the bottom up. Should any blade damage occur, just the section damaged can be replaced by simply unbolting it and bolting on a new one. The slat structure allows air to flow through the blade while moving down the road and not plowing snow, enabling air to enter the radiator section of the vehicle to cool the radiator more efficiently. Finally, the slat structure is envisioned to create lift, in much the same manner as an airplane wing, thus making the blade appear lighter than its actual static weight when moving down the road and not plowing snow. This feature is envisioned to reduce wear and tear on suspension components, steering components, tires, and other similar items.

Snow plows are typically used to remove accumulated snow from streets and parking lots. While the effort of moving snow from one (1) part of a paved surface to another seems at first relatively straightforward, there are multiple issues to consider when evaluating the snow plow itself. First, there are fuel factors to be considered when driving around with it on the truck and not plowing snow. Secondly, the weight of the plow places additional burden on the suspension of the truck causing premature failure. Finally, the position of the plow, when not in use, forms a perfect barrier for the radiator possibly causing overheating problems. Accordingly, there exists a need for a means by which snow plows can address the disadvantages and their associated costs as addressed above. The development of the apparatus herein described fulfills this need.
There have been attempts in the past to invent refined snow plows. U.S. Pat. No. 6,112,438 issued to Weagley discloses a snow plow that appears to be foldably collapsible toward a center section. Unfortunately, this patent does not appear to disclose an upper, middle and lower blade that are positioned upon structural frame members in such a manner as to leave an opening for air to flow through the snow plow and decrease wind resistance on the plow.
U.S. Pat. No. 6,044,579 issued to Hadler et al. discloses an articulated snowplow system that appears to comprise an angled snow plow that comprises rams on either side of the center to adjust the horizontal angle of the blades. Unfortunately, this patent does not appear to disclose three (3) snow plow blades that are mounted one (1) on top of the other in a horizontal manner so as to reduce wind resistance and wear on a vehicle's suspension.
U.S. Pat. No. 6,035,560 issued to Pender discloses an air deflector with adjustable louver that is mounted on the upper surface of a snow plow. Unfortunately, this patent does not appear to disclose a louvered mechanism that is part of the snow plow, nor does it appear to disclose a series of three (3) blades that provide an opening for air passage to the radiator of a vehicle.
U.S. Pat. No. 5,966,845 issued to DiGiacomo discloses an air stream deflector mountable thereto a snow plow. Unfortunately, this patent does not appear to disclose a louvered design snow plow that provides three (3) blades that permit the passage of air through the plow.
U.S. Pat. No. 5,819,444 issued to Desmarais discloses a snow blade with tiltable lateral panels connected by hinges. Unfortunately, this patent does not appear to disclose three snow plow blades horizontally positioned upon one another which provide a gap for air to circulate through the plow to the radiator, consequently improving fuel economy and wear on the dedicated vehicle's suspension.
U.S. Pat. No. D 396,236 issued to Eberle discloses a snow plow with a blade that is angled from the vertical center of the device. Unfortunately, this design patent does not appear to be similar in appearance to the disclosed apparatus, nor does it appear to comprise an upper, middle and lower blade that are attached to mounting members and permit airflow through the snow plow.
U.S. Pat. No. D 377,653 issued to Matisz et al. discloses an angled snow plow blade structure. Unfortunately, this design patent does not appear to be similar in appearance to the disclosed apparatus, nor does it appear to possess three (3) blades that are connected by frame members that permit air flow through the plow structure.
U.S. Pat. No. 5,544,434 issued top Calvachio discloses an air flow deflector that mounts on top of a snow plow. Unfortunately, this patent does not appear to disclose a louvered mechanism that is part of the snow plow, nor does it appear to disclose a series of three (3) blades that provide an opening for air passage to the radiator of a vehicle.
U.S. Pat. No. D 310,225 issued to Matisz et al discloses an angled snow plow blade. Unfortunately, this design patent does not appear to be similar in appearance to the disclosed apparatus, nor does it appear to comprise an upper, middle and lower blade that are attached to mounting members and permit airflow through the snow plow.
U.S. Pat. No. 4,896,915 issued to Morandi discloses a wind deflector plate for snow plow that appears to comprise a deflecting plate mounted on top of a plow which directs air when moving to the rear of the plow and the radiator of a motor vehicle. Unfortunately, this patent does not appear to disclose a louvered design snow plow that comprises three (3) horizontally mounted blades positioned in such a manner as to permit air circulation through the plow.
U.S. Pat. No. 4,794,710 issued to Haring discloses a snowplow blade with spring-loaded edge flaps. Unfortunately, this patent does not appear to disclose a louvered design snow plow which permits air circulation through the plow.
U.S. Pat. No. 4,587,750 issued to Larson discloses an air scoop mounted on snow plow. Unfortunately, this patent does not appear to disclose a louvered design snow plow that comprises three horizontally mounted blades positioned in such a manner as to permit air circulation through the plow.
U.S. Pat. No. 2,085,996 issued to Phillips discloses a snow plow deflector that appears to comprise a circular deflector mounted on an upper surface of a snow plow to direct air to a radiator of a motor vehicle. Unfortunately, this patent does not appear to disclose three (3) snow plow blades horizontally positioned upon one (1) another which provide a gap for air to circulate through the plow to the radiator, consequently improving fuel economy and wear on the dedicated vehicle's suspension.
None of the prior art particularly describes a snow plow for a motor vehicle comprising a plurality of blades in a staggered arrangement, thereby allowing replacement of an individual blade should any damage occur and air to flow through said plurality of blades enabling air to cool a radiator of the motor vehicle more efficiently that the instant apparatus possesses. Accordingly, there exists a need for snow plow that operates without the disadvantages as described above.


A search query is applied to documents in a document repository wherein the documents are organized into a hierarchy. A search engine searches the hierarchy to return documents which match a query term either directly or indirectly. A specific embodiment of the search engine organizes the query term into individual subterms and matches the subterms against documents, returning only those documents which indirectly match the entire search query term and directly match at least one of the query subterms.

The present invention relates to the field of electronic document storage and management. More specifically, one embodiment of the invention provides for a system of storing compound documents and searching the stored compound documents.
Information has recently undergone a transition from a scarce commodity to an overabundant commodity. With a scarce commodity, efforts are centered on acquiring the commodity, whereas with an overabundant commodity, efforts are centered on filtering the commodity to make it more valuable. The prime example of this phenomenon is the explosion of information resulting from the growth of the global internetwork of networks known as the "Internet." Networks and computers connected to the Internet pass data using the TCP/IP (Transport Control Protocol/Internet Protocol) for reliably passing data packets from a source node to a destination node. A variety of higher level protocols are used on top of TCP/IP to transport objects of digital data, the particular protocol depending on the nature of the objects. For example, e-mail is transported using the Simple Mail Transport Protocol (SMTP) and the Post Office Protocol 3 (POP3), while files are transported using the File Transfer Protocol (FTP). Hypertext documents and their associated effects are transported using the Hypertext Transport Protocol (HTTP).
When many hypertext documents are linked to other hypertext documents, they collectively form a "web" structure, which led to the name "World Wide Web" (often shortened to "WWW" or "the Web") for the collection of hypertext documents that can be transported using HTTP. Of course, hyperlinks are not required in a document for it to be transported using HTTP. In fact, any object can be transported using HTTP, so long as it conforms to the requirements of HTTP.
In a typical use of HTTP, a browser sends a uniform resource locator (URL) to a Web server and the Web server returns a Hypertext Markup Language (HTML) document for the browser to display. The browser is one example of an HTTP client and is so named because it displays the returned hypertext document and allows the user an opportunity to select and display other hypertext documents referenced in the returned document. The Web server is an Internet node which returns hypertext documents requested by HTTP clients.
Some Web servers, in addition to serving static documents, can return dynamic documents. A static document is a document which exists on a Web server before a request for the document is made and for which the Web server merely sends out the static document upon request. A static page URL is typically in the form of "host.subdomain.domain.TLD/path/file" or the like. That static page URL refers to a document named "file" which is found on the path "/path/" on the machine which has the domain name "host.subdomain.domain.TLD". An actual domain "www.yahoo.com", refers to the machine (or machines) designated "www" at the domain "yahoo" in the ".com" top-level domain (TLD). By contrast, a dynamic document is a document which is generated by the Web server when it receives a particular URL which the server identifies as a request for a dynamic document.
Many Web servers operate "Web sites" which offer a collection of linked hypertext documents controlled by a single person or entity. Since the Web site is controlled by a single person or entity, the hypertext documents, often called "Web pages" in this context, have a consistent look and subject matter. Especially in the case of Web sites put up by commercial interests selling goods and services, the hyperlinked documents which form a Web site will have few, if any, links to pages not controlled by the interest. The terms "Web site" and "Web page" are often used interchangeably, but herein a "Web page" refers to a single hypertext document which forms part of a Web site and "Web site" refers to a collection of one or more Web pages which are controlled (i.e., modifiable) by a single entity or group of entities working in concert to present a site on a particular topic.
With all the many sites and pages that the many millions of Internet users might make available through their Web servers, it is often difficult to find a particular page or determine where to find information on a particular topic. There is no "official" listing of what is available, because anyone can place anything on their Web server and need not report it to an official agency and the Web changes so quickly. In the absence of an official "table of contents", several approaches to indexing the Web have been proposed.
One approach is to index all of the Web documents found everywhere. While this approach is useful to find a document on a rarely discussed topic or a reference to a person with an uncommon first or last name, it often leads to excessive numbers of "hits." Another approach is to summarize and categorize web documents and make the summaries searchable by category.
In either case, a typical search engine searches for search terms in each candidate document and returns a list of the documents which meet the search criteria. Unfortunately, the information to be gained from the interrelationships of documents is lost. From the above it is seen that an improved search system which takes into account the interrelationships between documents is needed.

Information retrieval from hierarchical compound documents