A method for converting a sequence of scan-only film captured images into a sequence of modified images that provide the appearance of images captured by a photographic film reproduction system; the photographic film reproduction system being includes photographic motion picture negative film printed onto a motion picture print film that is displayed, or a reversal motion picture system in which the reversal film is displayed, or a photographic motion picture film electro-optically scanned to standard format video by a telecine and further displayed, or a photographic motion picture film electro-optically scanned by a scanner suitable for producing digital data intended for additional digital image manipulation and further preparation as a digital master for electronic distribution such as digital theatrical projection or various types of broadcast video; or recorded out to another photographic film to be used as a printing master for producing distribution optical prints for theatrical projection.

Traditionally, high quality motion picture images are captured by a photographic film. The primary benefits of film over other image capture technologies for motion picture applications include wide exposure dynamic range, preferred color reproduction control, a desired level of texture (image grain), fast photographic speed, high resolution and sharpness, and flexibility in framing through various post-production operations. In general, motion picture images are used for exhibition in either theatrical projection or broadcast television distribution.
Color images on photographic film are produced by exposing light-sensitive layers coated on a flexible semi-transparent support through a film camera and lens, and subjecting the film to prescribed chemical amplification processes to produce dyes with a predictable optical density profile. In typical motion picture applications, the original captured film image can be further printed optically onto another piece of intermediate or print motion picture film as suitable for theatrical projection or the optical density signature recorded on the film can be transferred to digital data on a film scanner. Once scanned, image manipulation can be imparted by way of a color corrector or various other digital intermediate techniques suitable for preparing the image for distribution (television broadcast, theatrical projection, etc.).
Photographic color negative films create complementary cyan, magenta, and yellow dye amounts from red green, and blue exposure, respectively. Dye amount is directly proportional to incident light intensity. The negative image is inverted by optically printing onto another negative-acting motion picture film or by processing downstream of a scanner in order to render it suitable for positive display. Photographic color positive films create complementary cyan, magenta, and yellow dye amounts from red, green, and blue exposure also, but the dye amount is inversely proportional to incident intensity. This allows for the positive image to be directly projected in theatrical distribution or to be scanned without a required polarity inversion.
For theatrical exhibition of images captured by film but digitized for the purpose of creative enhancement or the addition of visual effects, calibrated electro-optical scanners are used to convert film density to digital data suitable for electronic display (monitor or digital cinema, for example) or to digital data suitable for driving a film recorder to produce a reproduction of the original image on another piece of film. In the case of the film recorder example, the new film image produced can be used to generate distribution prints for exhibition in typical motion picture cinema theaters.
For broadcast television exhibition, electro-optical scanners known as telecines are used to convert film density to voltage signals suitable for driving a typical display/broadcast monitor.
When images captured with conventional motion picture origination film are chemically developed, and then optically transferred to print film or electro-optically scanned for electronic processing/display, they produce an image appearance that is primarily inherent of the "origination" film's tone, color, sharpness and texture (i.e. graininess). These "origination film attributes" all contribute to what cinematographers describe as the "film look." A number of origination films are manufactured for the purpose of producing several "film looks" to satisfy the various creative needs of cinematographers. The unique look of each of these films is primarily determined by the type of light sensitive (spectral) and image processing chemistry incorporated into the film's color recording emulsions. If an alternate "image processing" means (method) were available to reproduce the many origination film looks without having the need for incorporating separate chemistry formulations in each film type, it would be advantageous (e.g. cost/workflow efficiency) to theatrical and television film productions. For instance, producers would no longer have a need to carry/track inventory for the several origination film types to satisfy the production needs (looks) of the cinematographer.
Also by removing the requirement for an origination film stock to possess "film-look-ready" images for either optical printing steps or electro-optical scanning steps, the origination film chemistry could now be altered and aimed more efficiently at capturing a higher degree of scene information, as well as producing the corresponding developed image with optical attributes that would allow for greater information to be extracted (being better matched to a scanner's electro-optical characteristics). The film would need to be scanned (a type of "scan-only" film) so that the "image processing" chemistry that was removed (to give an origination film its unique look) could now be applied during a post image processing stage (via software and/or hardware) to achieve the various origination "film stock" looks. The image processing would implement algorithms (in the form of mathematical matrices, 3D look-up tables, or equations) with parameters/values assigned to reproduce the unique film look associated with the particular image processing chemistry formulation that exists in a conventional origination film type. This type of film would allow implementing the same type of image processing algorithms and functional workflow as described in the electronic capture/processing system of U.S. Pat. No. 6,269,217 B1 (after having undergone chemical development and optical scanning). This reference describes not only color, tone, sharpness and texture (graininess) processing, but also the processing needed to compensate for geometric (framing) and psychophysical viewing phenomena associated with image viewing conditions as well as the processing required to prepare images for specific display devices. Relative to current electronically captured images, origination film emulsion technology (e.g. Kodak ECN films) used in motion picture films can reproduce color image data with wider scene exposure latitude (especially in scene highlights and overexposures) and red/green/blue spatial resolution, in addition to being able to provide a longer archival image record (optical) than the current magnetic (e.g. tape) or electro-optic (e.g. optical disk) media used to record/store the image signals from electronic motion cameras.
Several valid examples of related prior art have been investigated to determine their relevancy to the present invention. Digital image processing may take place on video images, as described in U.S. Pat. Nos. 5,335,013; 5,475,425 and 5,831,673, in order to emulate the broadcast look of film or the look of film after it has been through a telecine transfer. These patents describe systems for rendering the output of a video camera to simulate the visual appearance of motion picture film that has been transferred or converted to a video signal to be output directly for television broadcasting or recording on video tape. Further, the above-cited prior art teaches three components for the emulation of the look of broadcast motion picture film. One component deals with the conversion of the video or digital material into various video formats from either 30 frames per second (fps) or 24 fps origination rate. The second component allows for the selective addition of filtered random-type noise to the electronically captured images to give the appearance of motion picture film grain. The third component allows for the alteration of the apparent contrast of the video image so the desired broadcast film appearance may be obtained. More specifically, in the '013 patent a gray scale modifier is used as a look-up table (LUT) and the operator can choose between a variety of curves (% light level vs. video level) stored in programmable read-only memory (PROM) to reflect different film types or achieve different photographic effects. The desired curve is selected by pressing a switch on the hardware. None of these patents refers to a system for manipulating images to match the color/tone characteristics of photographic motion picture films where the starting image is derived from an electro-optical scan of a scan-only film. Further, none reference the electronic processing of scanned images where the primary image space is data and not video.
U.S. Pat. Nos. 5,140,414; 5,374,954; and 5,406,326 (each issued to Mowry) represent a family of related post-production video technology that seeks to arrive at an aesthetically acceptable simulation of the appearance that images originated on different motion picture film stocks would embody after telecine "flying spot scanner" transfer to video from taped high definition video originated images. U.S. Pat. Nos. 5,457,491 and 5,687,011 further extend the concept to providing emulations of images captured on one medium from the capture of the image on a second medium, presumably to include any film capture medium. One component of this prior art technology deals with the conversion of the video-originated material through a LUT that is based on color temperature of the scene lighting, scene brightness and selected f-stop setting. The conversion values in the LUT are derived by filming color charts and gray-scale charts, obtaining a digital representation of the film component responses of the charts from telecine transfer of the film to videotape, and then charting the telecine-derived component responses against video originated images of the same charts under identical lighting conditions. Another component of this prior art technology allows for optically superimposing selected film grain patterns to the video images. The final simulated video image is either recorded as a high definition signal, or converted to an NTSC signal and broadcast or displayed.
In the latter two of the aforementioned Mowry patents, the digitized video signal may be sent to a film recorder, which reproduces the component-modified images onto a selected, reversal film stock. The film is chemically processed with a film processor and then optically projected, or scanned to video, digital video, or other electronic media. However, if the film recording option is employed, these patents specify that it is important that the telecine-derived LUT used in the component modification involves response data which compensates for the inherent color response of the film stock on which the images are being digitally recorded.
In all of the Mowry patents, the creation of image processing LUTs capable of transforming image data representative of the characteristics of one medium to characteristics representative of a second medium, those characteristics including color and tone among others, requires that reference images be necessarily captured on both media to provide statistical basis for the relationship algorithm.
U.S. Pat. Nos. 6,771,323, and 5,840,470 teach how fundamental image characteristic data can be used to provide device-independent or device-dependent intermediate data appropriate for simulating the image characteristics of multiple capture or display media and devices, including film, computer monitors, or video signals from a given image capture device or media. It focuses on capturing imaging device properties such as white level, black level, color level, linearity, and frequency response, and adding those image characteristics to primary scene content to yield enhanced content. It does not, however, reference the full gamut of motion picture color film imaging characteristics necessary to provide completely independent intermediate data, specifically those relevant to the properties of color reproduction. Further it does not acknowledge how some intermediate image spaces, such as scene exposure or scene luminance, must still be qualified by the spectral response properties of imaging devices and converted appropriately to provide full emulation of alternate imaging devices.
Another prior art example of post-production digital image processing, where the digital image could originate from an electronic camera or an electro-optical scan of a film frame, exists in certain current image manipulation software packages. FIG. 1 shows a schematic diagram of one such example of this type of prior art processing, namely, histogram equalization. The histogram equalization method requires, for every frame 1 of a digital image that is to be manipulated, a scanned frame 2 of a reference film preferably with, for optimal results, the same scene content. Some resizing constraints 3 might also have to be met, depending on the software, because the digital image and the scanned film image will most likely not be the same size. Then, with these two input images, a well-known cumulative histogram equalization process 4 is performed to manipulate the digital images closer to a film tonescale and color, thereby providing output manipulated images 5. This method, however, is not optimal for digital images because its inputs can be of mixed formats, especially in the case electronically captured images: some form of RGB exposures from the electronically captured images versus the scanned film densities. As a result, it is impossible to optimally alter the tonescale and color of the electronically captured image to emulate scene exposure as seen by film. For digital images created from electro-optical scans of film frames, the technique also presents problems as only scene color and tone content represented in the references frames can be properly compared. This necessarily excludes specific scene tone and color gamut information not represented in the reference frames. A final limitation of the method is that a reference frame is always required to produce the desired result, leading to impractical image capture scenarios in most common applications.
In a combined approach, U.S. Pat. No. 5,319,465 describes a method using modified camera production and modified post-production processes and equipment to create filmic images. Specifically, the method includes the steps of shooting a benchmark comprising a gray scale chart, a color test chart and two backfocus charts with both a film and a video camera with comparable scene lighting and depth of field. Once the film test benchmark is shot, the film is transferred to videotape utilizing a telecine apparatus, with settings indicative of an industry standard set-up film. The video camera image's hue, saturation, luminance and gamma levels are manipulated to color correct the video camera image to look visually like the transferred film image. After the videotape has been edited, the videotape undergoes color correction in which the videotape benchmark is corrected to match the film test benchmark.
The prior art is generally trying to emulate the look of film after it has been telecine-transferred to video. This is desirable to some extent because the telecine system does have some film attributes when broadcasted. However, the prior art neglects the emulation of the look of film origination, as if a negative film has been directly printed and projected through a motion picture system. This is particularly desirable where the digital output is recorded on film for projection. Where the prior art does deal with film recording, as in the latter two of the above-mentioned Mowry patents, it does so in the context of a telecine-transferred benchmark. Moreover, when the prior art alters the tone scale and color of a video or digitally captured image to emulate a film, it is done on the telecine-transferred benchmark. This is an imperfect alteration because it cannot operate upon the scene exposure as seen by a film.
What is needed is a system that correctly emulates the look of photographic film origination, when the origination film is now a "scan-only" type of film that lacks the image processing chemistry to provide the image look associated with a specified photographic origination film stock, particularly as to the emulation of film tonescale and color reproduction, as if a photographic origination film has been directly printed and projected through a motion picture system.

This patent is subject to a terminal disclaimer.

System and method for processing images to emulate film tonescale and color


A computer-implemented method of generating an issue library from a corpus of documents defining a citation network includes semantically linking, by a computing device, electronic documents within the corpus of documents by pairing reasons-for-citing in citing documents with cited-text-areas in cited documents and storing citation entries associated with the semantically-linked electronic documents in a citation-pairing metadata file. The method may further include searching the citation-pairing metadata file for reasons-for-citing and cited-text-areas that are semantically similar to at least one issue to thereby group similar documents and reasons-for-citing by issue, and storing information regarding groups of semantically-similar reasons-for-citing and cited-text-areas in a plurality of issue library metadata entities. Each issue library metadata entity is associated with an individual issue.

1. Field
The present specification generally relates to methods for identifying specific issues discussed within corpus of documents and, more particularly, to methods for extracting and organizing such issues identified in the document corpus into a structured issue library.
2. Technical Background
Documents within a corpus are often linked together by citations. For example, legal documents and scientific articles often cite to previous works to support a particular rule, proposition or finding. In the legal corpus context, an author of a judicial opinion often cites previous cases in support of his or her own legal statement or rule. In turn, these cited cases have themselves also cited and/or been cited by other cases in support of the proposition-in-question (and so on). Therefore, selected documents within the corpus are intrinsically linked together around particular issues, and these links can be manifested in the form of citation networks.
Researchers often search the corpus for documents that discuss a particular issue or topic. They will use the citations to move forward and backward within the corpus to find additional relevant documents. However, documents, such as legal documents, may discuss many different topics or legal issues. Further, a document may cite a document for many different reasons. Two citations pointing to the same document may cite to the same document for different reasons. Currently, the researcher does not know the particular issue or topic that a citing document is citing a cited document for based on the citation alone. The researcher must therefore sift through the many different cited documents.
Additionally, for any research project, a researcher may typically only be interested in documents pertaining to a certain issue or issues. The research process is therefore frequently impeded when a researcher is presented with documents that are unrelated to the immediate issue(s)-in-question. Further, a manual backwards and forwards citation-searching based on citation may be a very time consuming endeavor when researching these selected issues within the corpus, as well as a process that leaves many users uncertain about whether they have actually explored the full-range networked connections in sufficient depth.
Accordingly, a need exists for alternative methods of extracting an organizing issues within a corpus of documents into an issue library that may be accessed to enhance document searching capabilities.

Systems and methods for generating issue libraries within a document corpus

LexisNexis, a Division of Reed Elsevier, Inc.


A multiple proximity sensors based electronic device is disclosed. The electronic device includes a plurality of proximity sensors, which are configured to iteratively capture at least one proximity parameter at predefined time intervals. A processor within the electronic device analyzes the at least one proximity parameter and determines, for each of the plurality of proximity sensors, a rate of change of the associated at least one proximity parameter in response to the analyzing. The processor further computes a stability factor for the electronic device based on the determined rate of change of the associated at least one proximity parameter for each of the plurality of proximity sensors. The processor further compares the stability factor with a stability threshold and determines a fall probability of the electronic device based on the comparison.

Ever since the advent of smartphones, proximity sensors have been widely used for one or more applications in smartphones. Proximity sensors may also be used in other electronic devices, for example, tablets or laptops. Proximity sensors gather information from surroundings and convert such gathered information into electrical or digital signals, which are then processed by an electronic device to performs preconfigured functionalities. Smartphones are embedded with a single proximity sensor, which is used to determine whether the smartphone's touch screen display is in close proximity to a user's face during an ongoing call or not. Accordingly, the smartphone turns off the touch screen display to optimize battery consumption and to avoid unintended touches on the touch screen display. However, in conventional devices (especially smartphones) the use of proximity sensors is mostly limited to the above mentioned application.
There is therefore, a need for an electronic device that is configured to employ multiple proximity sensors for enabling a variety of end applications.

Multiple proximity sensors based electronic device


A method and apparatus for providing a virtual sensor in real-time have been described. In one embodiment, a method to provide a virtual sensor in real-time includes identifying data indicating desired functionality. The method further includes executing the virtual sensor in real-time based on the identified data to generate an output of the virtual sensor with the output being used by at least one data analysis module in real-time for statistical process monitoring.

Many industries employ sophisticated manufacturing equipment that includes multiple sensors and controls, each of which may be carefully monitored during processing to ensure product quality. One method of monitoring the multiple sensors and controls is statistical process monitoring (a means of performing statistical analysis on sensor measurements and process control values (process variables)), which enables automatic detection and/or diagnosis of faults. A "fault" can be a malfunction or maladjustment of manufacturing equipment (e.g., deviation of a machine's operating parameters from intended values), or an indication of a need for preventive maintenance to prevent an imminent malfunction or maladjustment. Faults can produce defects in the devices being manufactured. Accordingly, one goal of statistical process monitoring is to detect and/or diagnose faults before they produce such defects.
One industry approach for statistical process monitoring includes collecting data, acquiring and storing data, analyzing data, and acting. Data is collected by various sensors located on the manufacturing equipment. However, these sensors may not be exposed or accessible. Data is then acquired from the manufacturing equipment and saved or stored in a database that can be located on a server. The data is acquired from various types of manufacturing equipment having different configurations and protocols which slows and complicates the acquisition of the data into the database.
Next, the data is analyzed which requires filtering (e.g., specific runs of semiconductor wafer) and possibly transformations of units. Also, the data must be pre-processed using complex algorithms (e.g., virtual sensors) in order to perform a meaningful analysis. Finally, action must be taken based on the data analysis. For example, faults or errors may indicate a malfunctioning equipment or a need to modify a process parameter immediately on the fly during real-time. The action usually occurs too late because the data analysis requires a significant amount of time. Furthermore, updating or creating new virtual sensors requires restarting or reinstalling the software application being run on a manufacturing machine.


A device and method for providing a portable wireless communication device having an external device interface, and which is capable of intelligently configuring itself to operate according to one of a plurality of operating modes according to the needs of an individual user are disclosed. An exemplary device comprises an interface configured to communicatively couple the portable wireless communication device with an external device, and circuitry configured to record an instance of a first operation configuration, detect a coupled external device, predict a most likely next operation mode responsive to recording the instance of the first operation configuration, configure the portable wireless communication device to operate according to a first operating mode in response to the predicted the most likely next operation mode, and communicate with the external device.

Portable wireless communication devices, such as cell phones, PDAs, and the like, have become increasingly more powerful with a growing number of features. In particular, portable wireless communication devices are becoming more complex with multiple modes of interacting with other devices. For example, many portable wireless communication devices currently may operate as a communications device and as data transfer device.
With the advances in information storage technology, portable wireless communication devices may also operate in a mass storage mode, wherein the portable wireless communication device may view an external device as a memory storage area, or the external device may view the portable wireless communication device as a memory storage device.
In addition, with the convergence of multi-media capabilities into portable wireless communication devices, portable wireless communication devices may use external devices as a media player, or may themselves be used by external devices as media players. Moreover, when augmented by the integration of digital rights management capabilities, portable wireless communication devices may operate in a digital rights management mode, wherein the portable wireless communication device may be used to securely play, store, or transfer media content such as digital music, digital video, and other protected media, as well as protected electronic files and software applications.
Accordingly, support for three or more varying modes of operation are becoming a necessity for many portable wireless communication devices. For example, three typical modes are: communications (COM) mode, mass storage (MS) mode, and digital rights management (DRM) mode.
In response to the greater number of operating modes available, portable wireless communication devices often must also be able to interface with a plurality of external devices.
One technique for interfacing with a plurality of external devices is for the portable wireless communication device to provide a plurality of interfaces wherein a user may plug an external device into an interface dedicated to a particular mode of operation. For example, a portable wireless communication device may use a proprietary interface for instances of being used in communications mode, and use a universal interface, such as a USB port, for instances of being used in digital rights management mode. However, as the number of modes of operation increase, the increasing the number of physical interfaces undesirably detracts from a device's ability to retain a compact form facto and increases costs.
Another technique is to use a single universal hardware interface for multiple operation methods. However, this technique would still require the user to configure the portable wireless communication device to operate in a particular mode, according to which external device it is coupled to, leading to complexity of operation and an unsatisfactory user experience.
Accordingly, there exists a strong need in the art for a system and method for peripheral device detection on a mobile handset serial port which addresses the above deficiencies.

System and method for peripheral device detection on mobile handset serial port


A xe2x80x98lifelinexe2x80x99 POTS back-up mechanism is operative to provide emergency plain old telephone service connectivity over a span-powered two-wire metallic digital subscriber loop pair, in response to a customer""s phone going off-hook, during a lack of normal operating condition of the digital circuit path. A ground fault interruption signal is generated in a remote terminal and used to activate respective POTS by-pass paths in the remote terminal and a central office terminal.

The present invention relates in general to telecommunication systems, and is particularly directed to a new and improved signaling arrangement and method for supplying emergency xe2x80x98lifelinexe2x80x99 plain old telephone service (POTS) connectivity over a two-wire metallic digital subscriber loop (DSL) pair, such as that employed for ISDN communications. A (quasi) ground fault interruption (GFI) signal is generated by a remote terminal (RT) in response to a customer""s POTS phone going off-hook, during a lack of normal operating condition of the DSL circuit. This GFI signal is used to activate a POTS by-pass path in the RT and a POTS by-pass path at a central office terminal (COT).
Digital telecommunication systems, such as, but not limited to integrated services digital network (ISDN) communication systems, enable telecommunication service providers to supply multiple types of signalling channels from a central office site using a local twisted pair, termed a digital subscriber loop (DSL), to a network termination interface at a customer premises site. FIG. 1 diagrammatically illustrates a reduced complexity example of a span-powered DSL system for supplying POTS and ISDN communication services over a local loop. As a non-limiting example, such a span-powered DSL system may be of the type described in the U.S. Pat. No. 5,774,316, to J. McGray et al, entitled: xe2x80x9cGround Fault Detector for Line-Powered Telephone Network,xe2x80x9d assigned to the assignee of the present application and the disclosure of which is incorporated herein.
As shown in FIG. 1, the span-powered DSL system comprises a central office site 1, located at a xe2x80x98westxe2x80x99 end of a twisted pair 30, and a customer premises site 2 that terminates the xe2x80x98eastxe2x80x99 end of the loop. The central office site 1 includes a conventional POTS switch 3 (such as a 5ESS switch manufactured by ATandT), which: contains a plurality of line termination circuits (or line cards) 4, and an ISDN switch 5, which contains a plurality of ISDN cards 6. These respective circuits are interfaced with the local loop 30 by means of multiplexer circuitry 7 within a central office terminal (COT) 10. Power for the COT 10 is provided by way of local isolated span supply 8, which is (transformer) coupled to the metallic link from the central office. At the customer premises site 2, the local loop 30 is coupled directly to a remote terminal 20, which serves a customer""s digital terminal equipment (DTE) 24 and local POTS phone 29. As in the central office terminal, these circuits are interfaced with local loop 30 by means of multiplexer circuitry 23; power for components of the remote terminal is provided by way of a local span supply 28, which is coupled to wireline link 30.
Although the public service commissions of local jurisdictions, where customer premises equipment is installed, require telephone service providers (regional Bell operating companies) to ensure that each customer is continuously provided with emergency (911) telephone service in the event the DSL equipment at the remote terminal becomes non-functional (such as may be due to a loss in synchronization or a less than fully synchronized condition of the digital circuitry), the service provider is not permitted to dictate that a subscriber install a particular piece of equipment.
As a consequence, service providers customarily require that their residential subscribers maintain a separate POTS line as an emergency xe2x80x98lifelinexe2x80x99 adjunct to the DSL (ISDN) service, so that the residential customer is, in effect, forced to subscribe to an additional form of xe2x80x98fire insurancexe2x80x99. Namely, the extra POTS line (which normally goes unused) is intended to prevent residential customers from losing access to telephone service, particularly in the event of an emergency, where expedient 911 service may be critical. Such a requirement obviously constitutes a substantial cost penalty to the customer, who is faced with both a potential installation fee, and an unwanted monthly bill for a normally unused auxiliary line.
In accordance with the present invention, the need to ensure continuous telephone service to a residential customer premises served by a DSL, such as one used for ISDN, without requiring that the customer pay for an additional (and potentially unnecessary) POTS line as an emergency back-up, is successfully addressed by a modification of conventional signaling circuits and network termination interface components of the central office terminal and the remote terminal to include an auxiliary POTS by-pass path. Each auxiliary path is normally decoupled from its terminal""s signaling equipment, but is controllably coupled in circuit with the wireline pair, so as to provide an emergency or xe2x80x98lifelinexe2x80x99 POTS by-pass path between the central office and the subscriber""s POTS phone in the event that the subscriber needs to place a POTS call during a less than fully functional condition of the DSL circuitry.
In particular, the remote terminal circuitry serving the customer premises site is augmented to generate a (quasi) GFI signal should two conditions occur. The first is a lack of normal operation of the DSL circuit, as may result from a lack of digital link synchronization, as a non-limiting example. The second condition is a POTS phone at the remote terminal going off-hook. Unless both of these conditions occur, signaling path connectivity is provided through the central office terminal and the remote terminal through DSL/POTS multiplexer circuitry and a pair of energized auxiliary relay circuits.
This normal operation connectivity state continues to be maintained, as long as such normal DSL operating conditions are present, so as to provide both analog and digital communications, including allowing customer to place a POTS call, by way of the fully operational DSL circuitry of each of the COT and the RT. This normal operation connectivity state will also be maintained in the absence of a fully functional DSL link, so long as there is no attempt by a customer to place a POTS call. While the absence of a fully functional DSL link could be due to an operational anomaly, it is also an inherent condition of the DSL link during initialization (including transmission and detection of a training sequence) of the DSL circuit.
If the customer attempts to place a POTS call (goes off-hook) during a less than fully functional state of the DSL circuit, the state of a DSL sync input to a POTS by-pass condition detector in the remote terminal will indicate non-proper operation of the digital circuit; in addition, the off-hook input to the POTS by-pass detector will be asserted. As a consequence, a (quasi) ground fault interrupt signal generation circuit will couple a (quasi) GFI signal to an RT power supply and relay control circuitry in the remote terminal, and al so over the wireline DSL path to GFI sense circuitry within the central office terminal.
In response to the GFI signal, control circuits in each of the COT and the RT de-energize relay circuits associated with respective POTS by-pass paths around the DSL multiplexers, and thereby provide a direct analog (POTS) by-pass signaling path between the customer""s POTS phone at the RT and a POTS switch at the COT. Once this POTS by-pass signaling path has been established between the customer""s POTS phone and the POTS switch, an on-hook detector in the central office terminal monitors the state of the by-pass link in order to determine when the call has ended (the customer has gone back on-hook).
When the POTS call has been terminated (the customer""s phone goes back on-hook), the on-hook detector signals the COT""s relay control circuit, causing the COT""s relay coil to be re-energized, thereby returning the relay switch condition in the COT to its energized state for normal DSL operation conditions and decoupling the POTS by-pass path in the COT. This relay switching operation in the COT also causes span power to be reapplied to the DSL link, re-establishing power in the RT. With span-sourced power restored in the RT, its relay control circuit re-energizes RT relay coils for the POTS by-pass path, decoupling the POTS by-pass path in the RT, and restoring the RT to normal DSL communications.

Quasi ground fault interruption signal-based activation of emergency pots by-pass paths for line-powered digital subscriber loop


According to one embodiment, an exposure apparatus inspection mask includes a substrate and a first pattern portion. The substrate has a major surface reflective to exposure light. The first pattern portion is provided on the major surface. The first pattern portion includes a first lower layer and a plurality of first reflection layers. The first lower layer is provided on the major surface and includes a plurality of first absorption layers periodically arranged at a prescribed pitch along a first direction parallel to the major surface and is absorptive to the exposure light. The plurality of first reflection layers are provided on a side of the first lower layer opposite to the substrate, are periodically arranged at the pitch along the first direction, expose at least part of each of the plurality of first absorption layers, and have higher reflectance for the exposure light than the first absorption layers.

With the miniaturization of semiconductor devices, the exposure light of the exposure apparatus used to manufacture semiconductor devices has been shifted to shorter wavelengths. For example, there are expectations for practical application of the exposure technique using extreme ultraviolet (EUV) light having a wavelength of 13.5 nanometers (nm). In such exposure using EUV light, transmissive lenses cannot be used because of the high absorption coefficient of the substance. Instead, a reflective optical system using mirrors is used. Thus, in exposure using EUV light, a reflection type photomask is used.
The development of a special technology for evaluating the performance of an exposure apparatus using a reflection type photomask is necessary.

Exposure apparatus inspection mask and exposure apparatus inspection method


A method is disclosed including providing a plurality of sets of virtual reality video content, the sets representing respective three-dimensional virtual spaces within which a user can be immersed and being associated with respective three-dimensional portions of a real-world space such that, when rendered to a user device, there is a partial overlap between at least two virtual spaces defining one or more overlapping zones. The method may also include determining the position of a user device within the real-world space and rendering one or more of the virtual spaces, or representation(s) thereof, for display to the user device dependent on the determined position or movement within the real-world space.

Virtual reality (VR) is a rapidly developing area of technology in which video content is provided, e.g. streamed, to a VR display system. As is known, the VR display system may be provided with a live or stored feed from a video content source, the feed representing a VR space or world for immersive output through the display system. In some embodiments, audio is provided, which may be spatial audio. A virtual space or virtual world is any computer-generated version of a space, for example a captured real world space, in which a user can be immersed through a display system such as a VR headset. A VR headset may be configured to provide VR video and audio content to the user, e.g. through the use of a pair of video screens and headphones incorporated within the headset.
Position and/or movement of the user device can enhance the immersive experience. Currently, most VR headsets use so-called three degrees of freedom (3DoF) which means that the head movement in the yaw, pitch and roll axes are measured and determine what the user sees. This facilitates the scene remaining largely static in a single location as the user rotates their head. A next stage may be referred to as 3DoF+, which may facilitate limited translational movement in Euclidean space in the range of, e.g. tens of centimetres, around a location. A yet further stage is a six degrees of freedom (6DoF) VR system, where the user is able to freely move in the Euclidean space and rotate their head in the yaw, pitch and roll axes. 6DoF VR systems and methods will enable the provision and consumption of volumetric VR content.
Volumetric VR content comprises data representing spaces and/or objects in three-dimensions from all angles, enabling the user to move fully around the spaces and/or objects to view them from any angle. For example, a person or object may be fully scanned and reproduced within a real-world space. When rendered to a VR headset, the user may 'walk around' the person or object and view them from the front, the sides and from behind.
A challenge exists in terms of providing a plurality of VR spaces or worlds for users located in a real-world space having limited dimensions. For example, a user may wish to select one or more VR spaces or worlds from a library of content for consumption in a room at home, at work or at school.
For the avoidance of doubt, references to VR are also intended to cover related technologies such as augmented reality (AR).


Method and system for predicting labels for nodes in an observed graph, including deriving a plurality of random graph realizations of the observed graph; learning a predictive function using the random graph realizations; predicting label probabilities for nodes of the random graph realizations using the learned predictive function; and averaging the predicted label probabilities to predict labels for the nodes of the observed graph.

A graph is a data structure consisting of nodes and edges that connect the nodes. Each node represents an object (also referred to an instance or event) in a set of objects and each edge represents a relationship that connects two nodes. Processing graphs using machine learning based systems is of growing interest due to the ability of graphs to represent objects and their inter-relationships across a number of areas including, among other things, social networks, financial networks, sets of documents (e.g. citation networks), and physical systems such as wireless communications networks. Machine learning based systems are, for example, being developed for inference tasks on graphs including node classification, regression, link prediction, sub-graph classification and clustering. Machine learning may, for example, be applied to learn a predictive model or function that can provide a label or other predictive output for nodes of a graph or infer a single label for an entire graph.
A raph neural network (GNN) can be trained to learn a model of the dependencies between nodes in a graph. A GNN is a type of artificial neural network (NN) that is configured to operate on the graph domain and can learn to perform inference tasks by considering examples. GNNs typically do not need to be programmed with any task-specific rules. Instead, GNNs learn from the examples they process. Graph convolutional neural networks (GCNNs), which are a type of GNN based on convolution neural network (CNN) techniques, have emerged over the past few years and have proved effective for graph learning.
A GNN can learn a predictive function (also commonly referred to as a predictive model) based on the features of individual nodes as well as the relationships between nodes and thus capture structural information about a graph while incorporating data contained in feature attributes of the nodes and edges. GNNs are applicable to a broad array of problems which require learning from data which have irregular but complex structures. For example, social networks can include nodes that specify social media user metadata, a knowledge graph can include nodes that specify factual data, and a citation network can include nodes that specify paper topics and abstracts. The edge connections between these nodes encode information not contained in any given node alone. A key component of a GNN, and graph-based machine learning systems in general, is an aggregating function which is able to consolidate data for a node as well as its neighbours and produce a succinct mathematical description of the local neighbourhood around the node.
Different GNN configurations (including neural network layers and embedded aggregating functions) have been proposed, some of which are also able to capture global patterns in graph structured data while others are crafted to scale to very large graphs (e.g. graphs having millions of nodes, and billions of edges). However, broadly speaking, almost every GNN assumes that links between nodes reflect homophily, i.e., that connected nodes share common attributes. The design of aggregator functions which take advantage of this assumption has yielded tremendous improvements on learning tasks for graph-structured data.
Although the performance of GNNs has been encouraging, the current implementations of GNNs (including GCNNs) have one or more fundamental limitations.
One limitation is that existing GCNN configurations assume that an input graph represents the ground-truth. In many cases however the graph needs to be derived from noisy data under some modelling assumptions. It is possible that during this process some important links get left out and some spurious links get added causing important deviations from original relationships between nodes.
A second limitation is sensitivity of existing GCNN configurations to error links. The graph topology of a graph is strong prior information, indicating two nodes share similar properties. When an error link exists, the aggregation function will combine features from a different category, which will jeopardize GCNN performance. This can be especially critical in the case of a deep graph convolution architecture in which false neighbor information will propagate to farther nodes, causing cascade side effects.
Another limitation is the overfitting problem. To acquire node embedding, the typical GCNN averages the latent features across the neighbor's latent representation from a previous layer. Given a limited quantity of labelled nodes within a graph, the overfitting problem is severe since each node aggregates the information from the same set of neighbors in each training iteration. This makes it hard to learn general latent features for nodes.
Another limitation is sensitivity to training node selection. In the context of semi-supervised learning, an objective is to use a limited set of labelled nodes in a graph to predict labels for other unlabeled nodes. Thus, the labelled nodes selected during the training process is crucial. If high degree nodes are used for the training set, the correctly labeled information can propagate to more nodes. However, if low degree nodes having a very limited number of neighbors are used for the training set, the graph model learning process is not effective.
Accordingly, there is a need for a machine learning solution that can be applied in the context of graph structured data to address one or more of the limitations noted above.

Bayesian graph convolutional neural networks

THE ROYAL INSTITUTION FOR THE ADVANCEMENT OF LEARNING/MCGILL UNIVERSITY


Embodiments of the present invention may provide a multi-string DAC with leakage current cancellation. A leakage cancellation circuit may be coupled to output node(s) of the—multi-string DAC. The leakage cancellation circuit may replicate leakage current present at the coupled output node(s) and generate a corresponding complementary signal, a leakage cancellation signal. The leakage cancellation signal may be injected into the coupled output node(s) to cancel (or reduce) the net impact of the leakage current.

The present invention relates to leakage current cancellation in string digital-to-analog converters (DACs).
String DACs convert a digital word into a corresponding analog signal. A dual string DAC, which is a string DAC type, includes two impedance strings such as two series connected resistor strings and two switch networks. The outputs of the first resistor string, which typically is used for converting the most significant bits (MSBs) of the digital word, is coupled to the input of the second resistor string, which typically is used for converting the least significant bits (LSBs) of the digital word. Thus, for medium-to-high resolution converters, the voltages at selected first resistor terminals are often close in value. The selected resistor in first resistor string, first switching network, and second resistor string may be operating at similar common-mode.
An error source in string DACs operating at a given common-mode is leakage current, which can corrupt the conversion. Leakage current can be present at the outputs of the switches in the two switch networks and can refer to the undesired current that "leaks" in to or from switch terminals. The impact of such leakage current becomes more substantial in low power and/or high temperature applications. In low power applications, small amounts of leakage current can lead to significant errors because of the low voltages used in the conversion. In high temperature applications, leakage current increases proportionally to increasing temperature (e.g., leakage current can substantially double every 10 degrees Celsius).
Therefore, the inventor recognized a need in the art for efficient leakage current cancellation.


A device for correcting fine superficial facial lines which comprises a syringe fitted with a 31-33 gauge needle and an aqueous suspension of noncrosslinked fibrillar atelopeptide collagen contained within the syringe barrel, the concentration of collagen in the suspension being in the range of 10 to 50 mg/ml and the suspension exhibiting an extrusion plot in which there is a smooth substantially linear increase in force up to a substantially constant force in the range of 5 to 30 newtons.

Injectable forms of purified atelopeptide collagen have been commercially available for many years for soft tissue augmentation. Daniels et al., U.S. Pat. No. 3,949,073, initiated the development of these materials. They describe an injectable solution of atelopeptide which when injected forms a fibrillar collagen implant. Forms of this material are now commercially available from Collagen Corporation (Palo Alto, Calif.) under the trademark ZYDERM.RTM.. ZYDERM.RTM. collagen implant is prepackaged in a one cc syringe (Medical Molding Co. of America) fitted with a 30 gauge needle.
U.S. Pat. No. 4,488,911 assigned to Collagen Corporation describe a method for preparing purified atelopeptide collagen in solution (CIS). Native collagen, typically of bovine origin, is extracted from tissue in dilute aqueous acid and then digested with a protease such as pepsin, trypsin or PRONASE.RTM. to remove the telopeptides from the ends of the collagen molecules. Atelopeptide collagen fibers may be reconstituted from CIS by raising the pH of the solution.
U.S. Pat. No. 4,582,640, also assigned to Collagen Corporation, describes a crosslinked form of atelopeptide fibrillar collagen. An injectable suspension of this crosslinked material is available commercially from Collagen Corporation under the trademark ZYPLAST.RTM.. This product is prepackaged in a syringe in the same manner as the ZYDERM.RTM. product.
U.S. Pat. No. 4,642,117, also assigned to Collagen Corporation, describes a method for reducing the viscosity of reconstituted CIS by passing the reconstituted fibers through a fine mesh screen.
ZYDERM.RTM. and ZYPLAST.RTM. collagen implants have enjoyed great commercial success and are used to treat a large variety of soft tissue anomalies. However, physicians have found one type of skin contour, fine superficial facial lines, particularly those about the eyes, (i.e., crows' feet) difficult to treat with these products. Specifically, physicians questioned about such treatment indicated inter alia that (1) they had negative experiences in using prior products due to lumpiness or beading of the injectate, (2) the nature of the skin surrounding the eye increased the possibility of the injection causing trauma or bruising of the area and (3) the treatment required greater control or precision than that which is achievable with these prior products.
Applicants addressed these shortcomings and found that a greatly improved product for treating fine superficial facial lines was achievable through a combination of modifying both the syringe and the injectate.

Device for treating fine superficial facial lines


To provide a channel selection method of a wireless communication system which enables a wireless station to select a wireless channel dynamically even when there are but an insufficient number of wireless channels, a channel selection method of selecting a wireless channel from a plurality of wireless channels prepared for the wireless communication system comprises: a channel search step (202) of checking whether any one of the plurality of wireless channels is left unused by other wireless stations of the wireless communication system or not; a sharing channel selection step (207) of selecting a wireless channel to be shared from wireless channels under use of the other wireless stations, said sharing channel selection step being performed when every of the plurality of wireless channels is found (205) to be under use of one of the other wireless stations at the channel search step; and a link establishment step of establishing the wireless link by sharing the wireless channel selected at the sharing channel selection step.

The present invention relates to a channel selection method to be applied to a wireless communication system wherein a plurality of wireless channels are used by a plurality of wireless stations, each selected dynamically according to usage of the wireless channels checked by each of the wireless stations, and particularly relates to the channel selection method which enables a dynamic and appropriate channel selection even when but few available wireless channels are left to be selected.
In conventional connection-less wireless communication systems to be applied to a wireless LAN (Local Area Network), for example, such as described in "Wireless LAN Medium Access Control and Physical Layer Specifications", Draft Standard IEEE 802.11, P802.11D2.0, (July 1995), (hereafter called the first prior document), a wireless channel is commonly used by a base station connected to a wired network and one or more mobile stations connected with the base station for configuring a wireless link of a wireless communication system, and a wireless channel is fixedly assigned to each base station considering propagation characteristics and the traffic prediction of each base station. The mobile station designates a wireless channel assigned to a base station of a zone where the mobile station actually exists, manually or according to a control signal which is periodically or continuously transmitted from the base station.
However, when the wireless channels are assigned fixedly for each of the base stations according to the propagation characteristics and the traffic prediction, there may occur interferences between base stations whereto the same wireless channel is assigned, if the actual propagation characteristics or the actual communication traffic is changed from the prediction.
For dealing with this problem, we proposed a dynamic channel selection method in a paper entitled "A Proposal of Packet DCA for a Wireless LAN System", B-652, p. 136, Proceedings of the Communication Society Congress 1996, IEICE, (hereafter called the second prior document), wherein an appropriate channel selection according to actual propagation characteristics and communication traffic is realized by enabling a wireless station to select a wireless channel not used by other wireless stations dynamically and independently, for establishing a new wireless link.
However, the channel selection method proposed in the second prior document is based on an assumption that a sufficient number of wireless channels are prepared so that there are always left some channels not used by other wireless stations and available for the new wireless link to be established, and there is no description concerning the case where no available channel is left unused. Therefore, there may arise wireless links whereto any wireless channel can be assigned, when the number of available wireless channels is insufficient.

Channel selection method of a wireless communication system


High-purity dibasic acid compositions are generally disclosed. In some embodiments, the dibasic acid compositions are solutions or suspensions. In some other embodiments, the compositions are solid-state compositions. In some such embodiments, the solid-state compositions include a dibasic acid as a crystalline solid and further include a low quantity of certain impurities, such as monobasic acids, various esters, and the like. Methods and systems for making such high-purity dibasic acid compositions are also disclosed.

Dibasic acids are organic compounds having two carboxylic acid groups. Such compounds can be used in a wide array of different ways. Because of their difunctionality, they are commonly used in making certain polymers. For example, a polyamide can be made by reacting a dibasic acid with a diamine, i.e., an organic compound having two amine groups. As another example, a polyester can be made by reacting a dibasic acid with a diol, i.e., an organic compound having two hydroxyl groups.
In certain instances, it may be desirable to use dibasic acids in a highly pure form, as the presence of impurities may cause certain undesirable events to occur. For example, if a dibasic acid composition contains a substantial amount of monobasic acid impurity, it can cause early chain termination in the polymerization process, thereby resulting in polymer chains that may have a lower molecular weight than desired.
Thus, there is a continuing need to develop cost-effective and scalable methods of making dibasic acids that result in high-purity compositions, especially compositions that have a low concentration of monobasic acid impurity.

High-purity dibasic acid compositions and methods of making the same


A method of processing seismic data, said seismic data having been obtained by: performing a plurality of sweeps, wherein each sweep comprises generating seismic signals in the earth using a plurality of vibrators by applying a pilot sweep wave-form to each vibrator, each pilot sweep being a waveform of changing frequency; measuring the force applied to the earth by each vibrator to determine a measured force waveform; and measuring the seismic signals at one or more locations remote from the vibrators; said method comprising: filtering the measured force waveform to remove harmonics of the pilot sweep and thus determining a filtered force waveform; generating an inversion operator from the filtered force waveform for each vibrator; and applying said inversion operator to the measured seismic signals to determine the contribution of each vibrator to the seismic signals.

This invention relates to methods for generating and processing simultaneous vibratory seismic data.
In seismic prospecting using simultaneous vibratory techniques, a series of seismic energy sources or vibrators are employed to transmit seismic signals into the earth. Part of these signals are reflected from interfaces between subterranean strata, and/or refracted within strata, back to the surface of the earth, where they are detected by one or more receivers. The time taken for a signal to pass from a particular vibrator to a particular receiver gives an indication of the length of travel of the signal between that vibrator and that receiver, from which the structure of geological formations may be deduced.
Vibrators generally consist of a base plate in contact with the ground, with a large weight applied to this plate. The seismic energy is transmitted to the ground by applying a vibratory force to the plate. Thus if a constant weight of 30 tonnes is applied to the metal plate, a vibration with amplitude 20 tonnes can be applied to the vibrator, ensuring that there is always a positive force against the ground.
Many modern vibratory seismic surveys are performed by simultaneously imparting energy into the earth from multiple source locations, so that each receiver will detect refracted and reflected energy which has been emitted by the whole series of vibrators. The data recorded at each receiver must then be processed so that the signal due to each individual vibrator can be separated out.
This is generally achieved by each vibrator performing multiple xe2x80x9csweepsxe2x80x9d or xe2x80x9cshotsxe2x80x9d, where the phase of the signals emitted by the vibrators are varied between vibrators and between shots. In its simplest form, this can be illustrated by the case of two vibrators, twice operated simultaneously. If they are operated in phase with each other for the first sweep, but 180xc2x0 out of phase for the second sweep, the receiver will record two signals. These signals may be added together to determine the signal arriving from the first vibrator, or subtracted to determine the signal arriving from the second vibrator.
In general, in order for the data arriving at each receiver to be decoded so that the contribution of each vibrator can be determined, there must be at least as many shots as there are vibrators. For each shot by each vibrator, a waveform is applied to that vibrator by the control mechanism. This waveform is normally a constant amplitude swept-frequency xe2x80x9cchirpxe2x80x9d, with tapered ends due to the fact that the amplitude has to be ramped up at the start and ramped down at the end, and is known as the xe2x80x9cpilot sweepxe2x80x9d. In modern seismic operations, the pilot sweep almost always begins at low frequency and finishes at high frequency, and the frequency normally increases linearly with respect to time.
In practice, the waveform actually applied to the ground by the vibrator is not quite the same as the waveform applied to the vibrator. Deviations from the pilot sweep are inevitable. These deviations have two characteristic forms:
1. As well as applying a force at the desired frequency (known as the fundamental), the vibrator also applies a force at integer multiples of that frequency (known as harmonics).
2. The force applied at the fundamental frequency deviates in amplitude and/or phase from the pilot sweep.
At each receiver, in order to separate out the signal from each vibrator, it is necessary to use some approximation of the signal provided by each vibrator. In the past, two methods have chiefly been used.
The first assumes that the vibrator force follows the pilot sweep exactly, and separates out the earth response due to the vibrator at each vibrator location accordingly. If such a method is used, the data at each receiver, or geophone, can be correlated with a single representative pilot sweep before separation. No measurements need to be made on the vibrator, and the procedure is robust. Non-linear effects such as a non-linear earth response or data clipping during acquisition will not leave significant artifacts.
The main disadvantage with this method is that deviations of the force applied at the fundamental from the pilot sweep can lead to significant cross-coupling of the vibrators, i.e. the signal from one vibrator being ascribed to another. This occurs if each vibrator has a different deviation from the pilot sweep. This method can also lead to timing errors for the individual vibrators.
The second known method uses a measurement of the force applied to the earth by the vibrator. Thus, instead of using the pilot sweep, the real force applied by the vibrator is used to derive an inversion operator. This removes the main disadvantage of using the pilot sweep, but itself has other disadvantages. The whole inversion procedure must be performed on uncorrelated data, the entire waveform of each shot must be acquired for each vibrator and each shot, and the method is sensitive to the non-linear effects described above.
In general, the data acquisition and much of the processing are performed separately. The data recorded by the receivers may be partially processed as it is received, but normally either raw or partially processed data is saved onto tapes which are then transferred to a central data processing unit.
According to a first aspect, the present invention provides method of processing seismic data, said seismic data having been obtained by:
performing a plurality of sweeps, wherein each sweep comprises generating seismic signals in the earth using a plurality of vibrators by applying a pilot sweep waveform to each vibrator, each pilot sweep being a waveform of changing frequency;
measuring the force applied to the earth by each vibrator to determine a measured force waveform; and
measuring the seismic signals at one or more locations remote from the vibrators;
said method comprising:
filtering the measured force waveform to remove harmonics of the pilot sweep and thus determining a filtered force waveform;
generating an inversion operator from the filtered force waveform for each vibrator; and
applying said inversion operator to the measured seismic signals to determine the contribution of each vibrator to the seismic signals.
The force waveform applied to the earth may be measured by special sensors, although preferably it is measured by derivation from the signal used by the vibrator controller to control the vibrator output. This may be a weighted sum measurement, consisting of a linear combination of signals from accelerometers on the vibrator.
The filtered force waveform may be determined by the application of a time varying notch filter to the measured force waveform, but more preferably the measured force waveform applied to the ground is filtered by cross-correlation with the pilot sweep followed by application of a time window to remove the harmonics of the pilot sweep. Each measured waveform may preferably be cross-correlated with the same pilot sweep. The time window is preferably applied around zero time.
The measured seismic signal is preferably also filtered by cross-correlation with the pilot sweep followed by application of a time window before the application of the inversion operator.
The pilot sweep preferably comprises a waveform having a substantially constant amplitude envelope with tapered ends, within which the frequency increases with time.
The number of sweeps may be the same as the number of vibrators. In another embodiment, the number of sweeps is greater than the number of vibrators, and the noise on each measured seismic signal is estimated and used in the determination of the inversion operator.
In a preferred embodiment, the invention provides a method of performing a seismic survey, comprising:
performing a plurality of sweeps, wherein each sweep comprises generating seismic signals in the earth using a plurality of vibrators by applying a pilot sweep waveform to each vibrator, each pilot sweep being a waveform of changing frequency;
measuring the force applied to the earth by each vibrator to determine a measured force waveform;
measuring the seismic signals at one or more locations remote from the vibrators; and
processing seismic data comprising the measured seismic signals and the measured force waveform using any of the methods described above.
At least in preferred embodiments, the data can be correlated before inversion, and the cross-coupling and timing error problems are removed. The method is not sensitive to non-linear effects. Further, a greatly reduced quantity of data need be recorded for each vibrator.
If there are the same number of vibrators as sweeps the inversion procedure is straightforward. However, the method may comprise taking more sweeps than there are vibrators.
According to a second aspect, the present invention provides a method of processing seismic data, said seismic data having been obtained by:
performing n sweeps, each sweep comprising generating seismic signals in the earth using nm vibrators in contact with the earth, where 12 is greater than m;
measuring the seismic signals at one or more locations remote from the vibrators to determine the seismic data; and
estimating the noise N associated with the seismic signals for each sweep;
the method comprising:
generating a noise correlation matrix P from the noise N associated with each sweep;
generating a nxc3x97m matrix M from the signal provided by each of the is sweeps at each of the m vibrators, each element of the matrix M corresponding to a source signature from one vibrator for one sweep: and
generating an inversion operator Mxe2x8axa5 for application to said seismic data, said inversion operator being determined by
Mxe2x8axa5=(M*P(xe2x88x921)M)(xe2x88x921)M*P(xe2x88x921).
The method preferably also comprises selecting rows from M in order to generate all possible square mxc3x97m sub-matrices of M;
wherein the inversion operator Mxe2x8axa5 is generated by performing a relative weighted sum of the inverses of the square mxc3x97m sub-matrices, where the relative weight applied to each inverse is the product of the elements of P corresponding to the rows omitted from M to generate the sub-matrix, multiplied by the absolute value of the determinant squared of the sub-matrix.
P may be determined by generating the component Pij of P in the ith column and jth row using Pij= less than NiNj* greater than .
Preferably, the inversion operator Mxe2x8axa5 is determined by       M    ⊥    =                              (                                    M              *                                                  P                              (                                  -                  1                                )                                                  M                    )                          (                      -            1                    )                                  M        *                          P                  (                      -            1                    )                      =                            ∑                      ij                                      xe2x80x83                                    …                                                        (                                          ∏                                  ij                                                        xe2x80x83                                                      …                                                                          P                k                                      )                                          (                                          "LeftBracketingBar"                                  det                                                        (                                          M                                              ij                                                                          xe2x80x83                                                                        …                                                              )                                                  "RightBracketingBar"                            2                        )                                          M                          ij                                            xe2x80x83                                          …                                      (                              -                1                            )                                                            ∑                      ij                                      xe2x80x83                                    …                                                        (                                          ∏                                  ij                                                        xe2x80x83                                                      …                                                                          P                i                                      )                                          (                                          "LeftBracketingBar"                                  det                                                        (                                          M                                              ij                                                                          xe2x80x83                                                                        …                                                              )                                                  "RightBracketingBar"                            2                        )
Where Mij . . . is the mxc3x97m sub-matrix.
There may be one more sweep than vibrator, in which case the inversion operator Mxe2x8axa5 may be determined by       M    ⊥    =                    ∑                  i          =          1                n                                    P          i                                              "LeftBracketingBar"                          det                                            (                                  M                  i                                )                                      "RightBracketingBar"                    2                                  M          i                      (                          -              1                        )                                              ∑                  i          =          1                n                                    P          i                                              "LeftBracketingBar"                          det                                            (                                  M                  i                                )                                      "RightBracketingBar"                    2
where Mi is the mxc3x97m sub-matrix omitting the ith row of M.
The noise power estimates may preferably be made using quadrature mirror filtering, although alternative methods such as discrete cosine transforms or discrete Fourier transforms may also be used.
In a preferred embodiment, the invention provides a method of performing a seismic survey, comprising:
performing n sweeps, wherein each sweep comprises generating seismic signals in the earth using m vibrators in contact with the earth, where n is greater than m;
measuring the seismic signals at one or more locations remote from the vibrators to determine seismic data;
estimating the noise N associated with the seismic signals for each sweep; and
processing the seismic data using any method described above.
According to a third aspect, the present invention provides a method of generating seismic data, comprising:
performing a plurality of sweeps, each sweep comprising generating seismic energy using a plurality of vibrators, each vibrator operating at a different phase, the power applied to each vibrator for each sweep being substantially the same;
wherein the phases are cycled through the vibrators, in such a way that for n vibrators labelled 1 to n, for each sweep after the first, vibrators number 2 to n use the phases of the vibrators 1 to nxe2x88x921 respectively from the previous sweep:
and wherein if a matrix is determined from the phases of the vibrators, with each column corresponding to one sweep and each row corresponding to one vibrator, the magnitude of the determinant of the matrix is the same as the dimension of the matrix if the phases of the vibrators are written as complex numbers.
The number of sweeps and number of vibrators may be the same. Alternatively, there may be more sweeps than vibrators, in which case a matrix for the phases of the vibrators may be determined as if there were as many vibrators as there are sweeps, and columns deleted from said matrix so that there are as many columns as there are vibrators.
Preferably, there is one more sweep than there is vibrator.
This method of determining the phases of the vibrators minimises the ambient noise at each receiver by keeping the size of the inversion operator as small as possible.
In preferred embodiments, a seismic survey may be conducted using seismic signals generated using the methods just described and processing data using any of the methods described above.
According to a fourth aspect, the present invention provides a computer readable medium carrying a computer program arranged to perform any of the methods described above.

Processing simultaneous vibratory seismic data


A method for obtaining high purity N-(2-hydroxyethyl)-2-pyrrolidone satisfactory for use as an intermediate material for N-vinyl-2-pyrrolidone from a reaction liquid formed of a reaction between y-butyrolactone and 2-aminoethanol, i.e., a liquid containing N-(2-hydroxyethyl)-2-pyrrolidone, compounds having boiling points lower than that of N-(2-hydroxyethyl)-2-pyrrolidone and compounds having boiling points higher than that of N-(2-hydroxyethyl)-2-pyrrolidone. The method is characterized by distilling said reaction liquid using a distillation column, whereby obtaining a liquid containing the compounds having the lower boiling points than that of N-(2-hydroxyethyl)-2-pyrrolidone and N-(2-hydroxyethyl)-2-pyrrolidone as a distillate liquid from the column top and a liquid containing compounds having boiling points higher than that of N-(2-hydroxyethyl)-2-pyrrolidone as a bottom liquid.

This invention relates to a method of purifying N-(2-hydroxyethyl)-2-pyrrolidone. N-vinyl-2-pyrrolidone, which is derived through intramolecular dehydration reaction of N-(2-hydroxyethyl)-2-pyrrolidone, is useful as starting monomer for poly-N-vinyl-2-pyrrolidone which has wide variety of utilities as a starting material for pharmaceuticals, food additives and cosmetics.
As a method of preparing N-(2-hydroxyethyl)-2-pyrrolidone, one comprising ring-opening and adding y-butyrolactone to 2-aminoethanol in liquid phase to form 4-hydroxy-N-(2-hydroxyethyl)-butanamide intermediate product, and then heating said intermediate product to cause its intramolecular dehydration reaction, while using water as the catalyst [Official Patent Gazettes of JP1972-21420 B, JP1974-20585 B and JP1979-22973 B (=U.S. Pat. No. 3,867,405)] is known.
Reaction products of the above method have complex composition composed of N-(2-hydroxyethyl)-2-pyrrolidone, water formed of the dehydration reaction, compounds having lower boiling points than N-(2-hydroxyethyl)-2-pyrrolidone (hereafter referred to as low-boiling component) and compounds having higher boiling points than N-(2-hydroxyethyl)-2-pyrrolidone (hereafter referred to as high-boiling component). Hence, for obtaining high purity (at the lowest 99.9% by weight) N-(2-hydroxyethyl)-2-pyrrolidone from the reaction products by removing the high-boiling component and low-boiling component, purification steps such as distillation is necessary. However, none of above cited Official Patent Gazettes contained any disclosure on a method for recovering high purity N-(2-hydroxyethyl)-2-pyrrolidone from said reaction products.
Whereas, as for N-methyl-2-pyrrolidone which is one of pyrrolidones but has entirely different physical properties from those of N-(2-hydroxyethyl)-2-pyrrolidone, methods of purification and recovery thereof have been disclosed in many Official Gazettes.
JP2,785,629 and JP3,024,414 disclose a production process of pyrrolidones characterized by distilling the low-boiling component off from the top of a first distillation column.
JP Kokai (laid-open) Gazette 2001-2638 A discloses a production process of high purity pyrrolidones, which comprises distilling the low-boiling component including unreacted amine and water off from the top of a first distillation column, setting the bottom liquid temperature of the first distillation column at 90-200xc2x0 C. and the average residence time of the bottom liquid, for 10 minutes to 8 hours; while extracting from the bottom of the same column the bottom liquid of an amount corresponding to 2-15% by weight of the pyrrolidones contained in the feed; and recovering the remaining part of the pyrrolidones as side cut. JP Kokai Gazette 2001-2640 A also discloses a production process of high purity pyrrolidones which comprises setting the bottom liquid temperature in the first distillation column at 90-200xc2x0 C. and the average residence time of the bottom liquid, for 10 minutes to 8 hours, while removing from the bottom of the first distillation column the bottom liquid of an amount corresponding to 2-15% by weight of the pyrrolidones contained in the feed, distilling the low-boiling component and the remaining pyrrolidones off from the column top, then supplying said column top distillate to a second distillation column, and distilling the low-boiling component off from the column top and recovering the pyrrolidones from the bottom of said column.
Thus, there is no prior art which disclosed a method for obtaining high purity N-(2-hydroxyethyl)-2-pyrrolidone of little low-boiling component content, which serves as an intermediate material to be used for synthesis of N-vinyl-2-pyrrolidone.
Gamma-butyrolactone, which is one of starting materials of N-(2-hydroxyethyl)-2-pyrrolidone, exhibits inert behavior during synthesis of N-vinyl-2-pyrrolidone. When y-butyrolactone remains in N-(2-hydroxyethyl)-2-pyrrolidone, most of it remains also during synthesis of N-vinyl-2-pyrrolidone.
Boiling temperature of y-butyrolactone is close to that of synthesized N-vinyl-2-pyrrolidone, and their separation in later purification step is difficult. In consequence, it provides a cause for lowering purity and increasing purification costs of resulting N-vinyl-2-pyrrolidone.
On the other hand, when 2-aminoethanol, which also is one of starting materials for N-(2-hydroxyethyl)-2-pyrrolidone, remains in N-(2-hydroxyethyl)-2-pyrrolidone, various heterocyclic amines are side produced during synthesis of N-vinyl-2-pyrrolidone, to cause coloring or unpleasant odor of resulting N-vinyl-2-pyrrolidone.
We tried purification of N-(2-hydroxyethyl)-2-pyrrolidone by distillation, referring to those processes described in Official Gazettes cited earlier, but could not obtain through any of those processes N-(2-hydroxyethyl)-2-pyrrolidone of high purity fully satisfactory for use as the intermediate material for N-vinyl-2-pyrrolidone.
In particular, under the operation conditions and bottom liquid temperature conditions as given in JP 2001-2638 A and JP 2001-2640 A, N-(2-hydroxyethyl)-2-pyrrolidone which was useful as a starting material of N-vinyl-2-pyrrolidone was not obtained at all. Presumably the operation conditions as described in the cited Kokai Gazettes are not applicable to production of N-(2-hydroxyethyl)-2-pyrrolidone because its physical properties largely differ from those of 2-pyrrolidones or N-alkyl-pyrrolidones which are the object compounds of the inventions described in those Gazettes. For example, for attaining the bottom liquid temperature of 90-200xc2x0 C. following the descriptions in those Gazettes, inside pressure of the column needs to be kept no higher than 6.67 hPa (5.0 mmHg). In that occasion the column top temperature becomes about 10xc2x0 C., and costs for cooling the condenser notably increase to bring about economical disadvantage.
After extensive studies, we came to discover: (1) because N-(2-hydroxyethyl)-2-pyrrolidone has higher boiling point than N-alkyl-pyrrolidones, the object compounds named in the cited Gazettes, generally high temperature operations inside the distillation column are inevitable; (2) because the high-boiling compounds in the reaction liquid have different structures from those in the processes of the cited Gazettes and have high reactivity, a part of the high-boiling component contained in the reaction liquid composition at the production time of N-(2-hydroxyethyl)-2-pyrrolidone undergoes pyrolysis during the distillative purification to form xcex3-butyrolactone or 2-aminoethanol; (3) according to the processes as described in the cited Gazettes, accompanying of such xcex3-butyrolactone or 2-aminoethanol, which are formed of pyrolysis, to N-(2-hydroxyethyl)-2-pyrrolidone is unavoidable; and (4) those phenomena are the causes why N-(2-hydroxyethyl)-2-pyrrolidone of high purity fully satisfactory for use as the intermediate material for N-vinyl-2-pyrrolidone cannot be obtained.
From the above-acquired knowledge, it is clear that recovery of N-(2-hydroxyethyl)-2-pyrrolidone from the products of the process described in said JP1979-22973 B (=U.S. Pat. No. 3,867,405) by means of conventional distillation operations is liable to invite purity degradation of N-(2-hydroxyethyl)-2-pyrrolidone due to pyrolysis of the high-boiling component contained in the reaction liquid.
Accordingly, therefore, an object of the present invention is to provide a method for obtaining high purity N-(2-hydroxyethyl)-2-pyrrolidone which is fully satisfactory for use as an intermediate material for N-vinyl-2-pyrrolidone, from a reaction liquid resulting from reacting xcex3-butyrolactone with 2-aminoethanol and containing N-(2-hydroxyethyl)-2-pyrrolidone, low-boiling component and high-boiling component.
We have made concentrative research work with the view to accomplish the above object, to find that high purity N-(2-hydroxyethyl)-2-pyrrolidone can be efficiently and stably recovered by, in the occasion of the recovery through distillation of the liquid resulting from reacting xcex3-butyrolactone with 2-aminoethanol and containing N-(2-hydroxyethyl)-2-pyrrolidone, low-boiling component and high-boiling component, first removing the high-boiling component and then removing the low-boiling component and remaining high-boiling component, whereby inhibiting blending of impurities formed of pyrolysis of the high-boiling component into the object product.
Thus, according to the invention a method of purifying N-(2-hydroxyethyl)-2-pyrrolidone is provided, which process comprising purifying a liquid resulting from reacting xcex3-butyrolactone with 2-aminoethanol and containing N-(2-hydroxyethyl)-2-pyrrolidone, compounds having lower boiling points than that of N-(2-hydroxyethyl)-2-pyrrolidone, and compounds having higher boiling points than that of N-(2-hydroxyethyl)-2-pyrrolidone, by distillation using a distillation column, said process being characterized by obtaining a liquid containing said compounds having lower boiling points than that of N-(2-hydroxyethyl)-2-pyrrolidone and N-(2-hydroxyethyl)2-pyrrolidone as the liquid distillate from the column top, while obtaining a liquid containing the compounds having boiling points higher than that of N-(2-hydroxyethyl)-2-pyrrolidone as the bottom liquid.
According to the method of this invention, said distillation column (which is hereafter referred to as the first distillation column) is preferably operated under the conditions of 200-260xc2x0 C. in bottom liquid temperature and 6.67-66.7 hPa (5.0-50 mmHg) in column top pressure.
According to the method of the invention, the distillate liquid from the first distillation column is distilled using a second distillation column, whereby obtaining a liquid containing the compounds having boiling points lower than that of N-(2-hydroxyethyl)-2-pyrrolidone as the distillate liquid from the column top, and concurrently, purified N-(2-hydroxyethyl)-2-pyrrolidone as a side cut from a position of the distillation column higher than the bottom.
According to the method of the present invention, said distillate liquid distilled off from the first distillation column is distilled using the second distillation column, whereby obtaining a liquid containing the compounds having boiling points lower than that of N-(2-hydroxyethyl)-2-pyrrolidone as the distillate liquid from the column top and a liquid containing N-(2-hydroxyethyl)-2-pyrrolidone as the bottom liquid; and then said bottom liquid is distilled using a third distillation column to provide purified N-(2-hydroxyethyl)-2-pyrrolidone as the distillate liquid.
In short, according to the invention high purity N-(2-hydroxyethyl)-2-pyrrolidone can be obtained by separating the high-boiling component, which undergoes pyrolysis to form xcex3-butyrolactone or 2-aminoethanol, from N-(2-hydroxyethyl)-2-pyrrolidone in the distillation step using the first distillation column (formation of pyrolyzed products in this step has no detrimental effect), and then distilling the separated N-(2-hydroxyethyl)-2-pyrrolidone using the second distillation column or the second and third distillation columns.

Method of purifying N-(2-hydroxyethy)-2-pyrrolidone


The invention relates to compounds of the formula 1

The invention relates to agents that inhibit hepatitis C virus (HCV) RNA-dependent RNA polymerase (RdRp). The invention also relates to the use of such compounds in pharmaceutical compositions and therapeutic treatments useful for inhibition of HCV replication.
HCV is an enveloped RNA virus containing a single-stranded positive-sense RNA genome approximately 9.5 kb in length (Choo et al., Science 244:359-362 (1989)). The RNA genome contains a 5′-nontranslated region (5′ NTR) of 341 nucleotides (Brown et al., Nucl. Acids Res. 20:5041-5045 (1992); Bukh et al., Proc. Natl. Acad. Sci. USA 89:4942-4946 (1992)), a large open reading frame (ORF) encoding a single polypeptide of 3,010 to 3,040 amino acids (Choo et al. (1989), supra), and a 3′-nontranslated region (3′-NTR) of variable length of about 230 nucleotides (Kolykhalov et al., J. Virol. 70:3363-3371 (1996); Tanaka et al., J. Virol. 70:3307-3312 (1996)).
The 5′ NTR is one of the most conserved regions of the viral genome and plays a pivotal role in the initiation of translation of the viral polyprotein (Bartenschlager (1997), supra). A single ORF encodes a polyprotein that is co- or post-translationally processed into structural (core, E1, and E2) and nonstructural (NS2, NS3, NS4A, NS4B, NS5A, and NS5B) viral proteins by either cellular or viral proteinases (Bartenschlager (1997), supra). The 3′ NTR consists of three distinct regions: a variable region of about 38 nucleotides following the stop codon of the polyprotein, a polyuridine tract of variable length with interspersed substitutions of cystines, and 98 nucleotides (nt) at the very 3′ end which are highly conserved among various HCV isolates. The order of the genes within the genome is: NH2-C-E1-E2-p7-NS2-NS3-NS4A-NS4B-NS5A-NS5B-COOH (Grakoui et al., J. Virol. 67:1385-1395 (1993)).
Hepatitis C virus (HCV) is a member of the hepacivirus genus in the family Flaviviridae. It is the major causative agent of non-A, non-B viral hepatitis and is the major cause of transfusion-associated hepatitis and accounts for a significant proportion of hepatitis cases worldwide. Although acute HCV infection is often asymptomatic, nearly 80% of cases resolve to chronic hepatitis. The persistent property of the HCV infection has been explained by its ability to escape from the host immune surveillance through hypermutability of the exposed regions in the envelope protein E2 (Weiner et al., Virology 180:842-848 (1991); Weiner et al. Proc. Natl. Acad. Sci. USA 89:3468-3472 (1992).
Processing of the structural proteins core (C), envelope protein 1 and (E1, E2), and the p7 region is mediated by host signal peptidases. In contrast, maturation of the nonstructural (NS) region is accomplished by two viral enzymes. The HCV polyprotein is first cleaved by a host signal peptidase generating the structural proteins C/E1, E1/E2, E2/p7, and p7/NS2 (Hijikata et al., Proc. Natl. Acad. Sci. USA 88:5547-5551 (1991); Lin et al., J. Virol. 68:5063-5073 (1994)). The NS2-3 proteinase, which is a metalloprotease, then cleaves at the NS2/NS3 junction. The NS3/4A proteinase complex (NS3 serine protease/NS4A cofactor), then at all the remaining cleavage sites (Bartenschlager et al., J. Virol. 67:3835-3844 (1993); Bartenschlager (1997), supra). RNA helicase and NTPase activities have also been identified in the NS3 protein. The N-terminal one-third of the NS3 protein functions as a protease, and the remaining two-thirds of the molecule acts as a helicase/ATPase, which is thought to be involved in HCV replication (Bartenschlager (1997), supra). NS5A may be phosphorylated and act as a putative cofactor of NS5B. The fourth viral enzyme, NS5B, is an RNA-dependent RNA polymerase (RdRp) and a key component responsible for replication of the viral RNA genome (Lohmann et al., J. Virol. 71:8416-8428 (1997)).
Replication of HCV is thought to occur in membrane-associated replication complexes. Within these, the genomic plus-strand RNA is transcribed into minus-strand RNA, which in turn can be used as a template for synthesis of progeny genomic plus strands. Two viral proteins appear to be involved in this reaction: the NS3 protein, which carries in the carboxy terminal two-thirds a nucleoside triphosphatase/RNA helicase, and the NS5B protein, which is a membrane-associated phosphoprotein with an RNA-dependent RNA polymerase activity (RdRp) (Hwang et al., J. Virol. 227:439-446 (1997)). While the role of NS3 in RNA replication is less clear, NS5B apparently is the key enzyme responsible for synthesis of progeny RNA strands. Using recombinant baculoviruses to express NS5B in insect cells and a synthetic nonviral RNA as a substrate, two enzymatic activities have been identified as being associated with NS5B. The two activities include a primer-dependent RdRp and a terminal transferase (TNTase) activity. NS5B's activity was confirmed and further characterized through the use of the HCV RNA genome as a substrate (Lohmann et al., Virology 249:108-118 (1998)). Recent studies have shown that NS5B with a C-terminal 21 amino-acid truncation expressed in Escherichia coli is also active for in vitro RNA synthesis (Ferrari et al., J. Virol. 73:1649-1654 (1999); Yamashita et al., J. Biol. Chem. 273:15479-15486 (1998)).
Since persistent infection of HCV is related to chronic hepatitis and eventually to hepatocarcinogenesis, HCV replication is one of the targets to eliminate HCV reproduction and to prevent hepatocellular carcinoma. Unfortunately, present treatment approaches for HCV infection are characterized by relatively poor efficacy and an unfavorable side-effect profile. Therefore, intensive effort is directed at the discovery of molecules to treat this disease, including the discovery of drugs designed to inhibit HC replication, as there is a persistent need for non-peptide, small-molecule compounds that are HCV RdRp inhibitors having desirable or improved physical and chemical properties appropriate for pharmaceutical applications.

Inhibitors of hepatitis C virus RNA-dependent RNA polymerase, and compositions and treatments using the same

Abstract: and to pharmaceutically acceptable salts, solvates, prodrugs and metabolites thereof, wherein W, Z, R1 and R2, are as defined herein. The invention also relates to methods of treating Hepatitis C virus in mammals by administering the compounds of formula 1, and to pharmaceutical compositions for treating such disorders, which contain the compounds of formula 1. The invention also relates to methods of preparing the compounds of formula 1.


A new and distinct variety of Crassula plant named ‘Daydream’ is disclosed, characterized by an unusual, stable, tricolor variegation, comprised of leaves with cream yellow margins, tipped with raspberry and often blushing rose in cooler weather. The central areas of the leaves are apple green, and exhibit occasional splashes of rose or cream yellow. In addition, the new cultivar ‘Daydream’ offsets heavily, enhancing production in the commercial nursery. The new variety is a Crassula, part of the Crasulaceae family that includes Crassula, Pachyphytum, Graptopetalum, Sedum and others. Crassula is a popular genus, typically produced as container plants or as landscape plants.

The new cultivar, Crassula 'Daydream', was found in an existing population of propagation stock plants of an unnamed variety of Crassula capitella in a commercial greenhouse in Vista, Calif. by the inventor. Crassula 'Daydream' is a naturally occurring branch mutation of the unnamed Crassula capitella. The new cultivar, Crassula 'Daydream' was discovered by the inventor in October of 2015.
Asexual reproduction of the new cultivar 'Daydream' was first performed in Vista, Calif., at a commercial greenhouse, by vegetative cuttings in February of 2016. 'Daydream' has since produced multiple generations and has shown that the unique features of this cultivar are stable and reproduced true to type.