A method and apparatus in a computer network system form a setup message at a source terminal. The setup message includes a bandwidth coordination message that identifies respective subchannel data rates to be used when sending data to respective destination terminals. The setup message identifies respective data rates and associated destination terminals, and the setup message is sent to a switch facility, that interconnects the source terminal and the respective destination terminals. The switch extracts the bandwidth coordination message and establishes subchannel links, such as subchannels of one or two ISDN B channels. Once the respective links are established, the source terminal transmits a message via the switch to the respective destination terminals at the data rates corresponding with the subchannel data rates established by the switch facility, and as requested by the source terminal.

1. Field of the Invention
The present invention pertains to communication systems and methods for communicating information over digital networks, such as an Integrated Services Digital Network (ISDN). In particular, the present invention pertains to establishing over an ISDN D channel one or more data rate selectable communication links between a source terminal and one or more destination terminals via a modified ISDN switch. The modified ISDN switch handles the aggregate bandwidth of two ISDN B channels as a common resource that is available for subdivision and allocation to one or more links to the one or more destination terminals. The aggregation of the two ISDN B channels, as well as the subdivision of the bandwidth afforded thereby, is performed without requiring the source and destination terminals to perform bonding or multilink protocol processes.
2. Discussion of the Background
Conventional facsimile devices communicate over the Public Switch Telephone Network (PSTN) using analog signals that are transmitted over conventional telephone lines. The source terminal (e.g., a facsimile device, computer with scanner and modem facilities, or another device that transmits and/or receives data) converts digital scanned information into a corresponding analog signal so the same may be sent over the PSTN telephone line, via a telephone switch facility, to the destination terminal. The source terminal receives the analog information and converts the analog information back into digital signals which form the basis of an image to be printed, perhaps on facsimile paper.
The Integrated Services Digital Network (ISDN) is emerging as a next generation worldwide public telecommunications network that will replace portions of the existing PSTN and provide a variety of services not offered by the PSTN. ISDN will allow for the transmission of various types of data between various types of ISDN terminal equipment (TE).
A portion of the ISDN link between a source terminal and a central office, which has a switch facility, is referred to as a xe2x80x9cdigital pipexe2x80x9d. A capacity of the digital pipe is generally discussed in terms of separate channels. In particular, a xe2x80x9cbasic accessxe2x80x9d digital pipe includes two B channels (basic channels) that each support 64 kbps signaling, and a D channel at 16 kbps. While the total bit rate of these three channels is 144 kbps, framing, synchronization and other overhead bits bring the total bit rate of a basic access link to 192 kbps. Furthermore, the B channels serve as separate communication channels such that the maximum data capacity, as view by the user, is 64 kbps per B channel, and 16 kbps for the D channel, not 192 kbps.
Conventional facsimile devices, such as G3 devices, send signals at rates not exceeding 64 kbps, because only one of the two B channels is used. Because facsimile data is arranged in a predetermined format, sending data over two separate B channels would be a sizable task because conventional ISDN switches handle the B channels separately, and thus may send data of one of the B channels over a completely different route than that of the other B channel. As a consequence, the different communication paths impose different communication delays on the respective B channels.
Other devices such as video teleconference facilities, assume the processing burden of xe2x80x9cbondingxe2x80x9d, or employing multilink point-to-point (multilink PPP) protocols, so as to increase data rates approaching 128 kbps. The bonding approach imposes a burden on the customer premise equipment (CPE) of dialing the ISDN switch and establishing the subsequent calls needed to achieve the desired data rate. Thus, two separate links are established. In particular, by assuming the burden of maintaining two separate communication connections with the ISDN switch, the CPE can give the appearance to a user that a 128 kbps channel is available to the user. However, the bonding approach is cumbersome in that the ISDN switch assumes each of the B channels may be handled independently, and therefore impart different delays into the separate B channels. As a consequence, the CPE must compensate for the delays between the respective B channels, and piece together the received and transmitted information so as to avoid synchronization problems.
Multilink PPP schemes attack the same problem from a different approach, although also placing a similar processing and data management burden on the CPE. The multilink PPP schemes use a conventional ISDN switch and attempts to make the ISDN switch oblivious to the operation of combining B channels to provide an effective data rate approaching 128 kbps. The multilink protocol involves dividing the user""s source data into specific fragments, including overhead information in the respective packets, so that the packets may be sent over all available channels, and later recombined in a contiguous fashion. As with bonding, multilink PPP places a computational and management burden on the CPE, rather than at the ISDN switch.
As recognized by the present inventor, a limitation with conventional ISDN networks and the source and destination terminals that operate therewith, is that the B channels are identified as static, fixed-bandwidth channels that may not be fully utilized by either the source or destination terminals. Moreover, while each B channel is allocated 64 kbps, a source or destination terminal may or may not be able to support the data rate, and thus may use the channel at lower data rates. However, the capacity for the channel remains at 64 kbps, and thus unless the source and destination terminals actually use a full 64 kbps signaling scheme, a portion of the available bandwidth (related to signaling speed) is wasted.
In light of this limitation, the present inventor identified that the xe2x80x9csubchannelizationxe2x80x9d of one or more ISDN B channels is not performed with conventional systems, but would be beneficial if the subchannelization allowed the xe2x80x9cwastedxe2x80x9d portion of the bandwidth to be used for other communication tasks. Moreover, if a modified ISDN switch were available that could receive a message, or messages, from the source terminal, and route the message, or messages, as subchannel messages to one or more destination terminals at a user-selectable subchannel bandwidth (i.e., data rate), significantly greater flexibility in terms of end-user communication speed, accessibility, and user-friendly operation could be achieved.
Conventionally, the function served by the ISDN D channel, is twofold. First, the D channel is used to establish and maintain signaling between the CPE and the ISDN switch (operated by the telephone company). Thus, the D channel carries signaling information such as that required for dialing the telephone number of the destination terminal and making the connection between the source terminal and the destination terminal. A more complete description of the D channel as employed in narrowband and broadband ISDN, as well as ISDN terminal equipment, protocols, data rates, etc. is provided in the literature, for example in Stallings, W., xe2x80x9cData and Computer Communicationsxe2x80x9d, 5th Edition, Prentice Hall, 1997, pages 740-769 (hereinafter xe2x80x9cStallingsxe2x80x9d), the contents of this book being incorporated herein by reference.
FIG. 1 is a block diagram of a conventional ISDN system 100 having a source facsimile 10 at a source facility 1 that communicates via an ISDN switch 22 to a destination facsimile 16 (or other type of destination terminal, such as a computer, ISDN equipped photocopier, etc.) in a destination facility 2. The source facsimile 10 communicates via a terminal adapter 10A, shown as an internal device, although a separate external terminal adapter may be used as well. The terminal adapter 10A provides a protocol (physical layer and intermediate layer) conversion function for converting signal protocols such as V.35, RS-232, Universal Serial Bus (USB), IEEE 1394 (FireWire), etc. to an ISDN compliant protocol over a 4-wire interface. In the source facility 1, the bonding or multilink PPP mechanism may be incorporated in the source terminal 10, terminal adapter 10A or in the NT114.
The NT114 connects the source facilities 1, via a two-wire line 15, to a switching module 26 located at the ISDN switch 22. Alternatively, a second network termination (NT2) may be used at the source facility 1 between NT1 and the terminal adapter to provide a switching and concentration function, such as with a digital private branch exchange (PBX). Likewise, the NT1 may be replaced with a NT12 that performs the functions of both the NT1 and NT2.
At the ISDN switch 22, the switching module 26 connects to a processor 24 and another switching module 28 via a bus 27, which allows digital commands and data to be passed between the respective switching modules 26 and 28, and the processor 24.
The equipment at the destination facility 2 may or may not be exactly similar to that of the source facilities 1. In the system shown in FIG. 1, the destination facility 2 includes the destination facsimile 16 having a terminal adapter 16A incorporated therein, which connects to another NT120 as shown. The NT120 connects to the switching module 28 in the ISDN switch 22, via another two-wire line 17 as shown. Several subaddresses 16S1-16SN may connect to the destination facsimile 16 by way of separate dedicated lines 18S1 to 18SN.
ISDN communications is based on a seven layer protocol stack, as explained in reference to FIG. A.5 of Stallings, for example. Control signaling is accomplished between the respective user-network interface and occurs at a third layer of the protocol stack (i.e., the xe2x80x9cnetworkxe2x80x9d layer) and is named I.451/Q.931. Thus, establishing and maintaining control signaling for a communication link is established between the source facility 1 and a destination ISDN facility 2 through the D channel, and in particular, the ISDN network layer, data link layer and physical layer.
FIG. 2 is a frame structure 200 of a transmission from the source facilities 1 to the ISDN switch 22, for an ISDN basic rate access. The frame structure 200 includes 48 bits which are transmitted in 250 xcexcsec. Components of the frame structure 200 include framing bits, F, dc balancing bits, L, B channel bits for the first B channel (16 per frame), B1, B channel bits for the second B channel (16 bits per frame), B2, D channel bits (4 per frame), D, auxiliary framing bit, Fa. A more detailed description of the frame structure, as well as a corresponding frame structure for the frames sent from the ISDN switch 22 to the source facilities 1, is described in Stallings, pp 212-215.
A link access protocol (LAPD) D channel is defined for establishing particular LAPD frames that are exchanged between the subscriber equipment (either at the source facility 1 or at the destination facility 2) and the ISDN switch 22. The call control protocol I.451/Q.931 is used on the D channel to establish, maintain and terminate connections on B channels.
The D channel is primarily used for signaling purposes and is used to dial the number of the destination terminal and establish the connection by which the data is transmitted from the source terminal 1 to the destination terminal 2 over the B channels. However, as presently recognized, once the D channel connection is established, the D channel may continue to be used free of charge to receive another call or to make additional connections for the second line, third line or the like, provided that the subchannelization feature is incorporated into the ISDN architecture. Thus, a synergistic effect of combining subchannelization with aggregating two B channels is that the common D channel allows for all the information regarding setup connections to be done by the D channel, without an additional charge to the ultimate users.
FIG. 3 illustrates the signaling sequence between the source facility 1 and the ISDN switch 22. In order to establish each B channel connection between the source facility 1 and the destination facility 2, an initial communication link must be established on the D channel between the source facility 1 and the destination facility 2. To this end, a series of messages is sent back and forth between the source facilities 1 and the ISDN switch 22. This communication between the source facilities 1 and ISDN switch 22 occurs on a continuing basis on the D channel, while communications are maintained between the source facilities 1 and destination facilities 2 on one of the B channels. As shown in FIG. 3, several different messages are sent between the source facilities 1 and ISDN switch 22 while the D channel is maintained. A similar, redundant procedure is performed when the second B channel is established for bonding or multilink PPP purposes.
The direction of the arrows in FIG. 3 indicates a direction of communication between the source facilities 1 and the ISDN switch 22. The process for establishing a connection is initiated by the source facilities 1 by first sending a setup message. Particular features of the setup message will be discussed with respect to FIG. 4, however the purpose of the setup message is to provide general information regarding the request to connect to the ISDN switch 22. Next, the ISDN switch 22 responds with a call proceeding message that indicates that call establishment has been initiated. Subsequently, the ISDN switch 22, sends a connect message that indicates call acceptance by the source facilities 1. The source facilities 1 then sends a connect acknowledge signal that indicates the user has been awarded the call. When the user wishes to disconnect a call, the user sends a disconnect message via the source facilities 1 to the ISDN switch 22, requesting connection clearing. In response, a release message is sent from the ISDN switch 22, indicating the intent to release the channel and call reference. In response the source facilities 1 issues a release complete message, indicating that the release of the channel and the call reference. Subsequently, the call and information flow through the B channel is terminated.
FIG. 4 shows the structure of a conventional ISDN D channel setup message. The setup message includes respective LAPD frames (e.g., 501, 503 . . . ) of different sizes (measured in octets). The message includes a flag frame 501 that is one octet in length, followed by a service access point identifier (SAPI) frame 503 having a command/response bit (CR) and address field extension bit (0). The SAPI frame 503 is joined with the terminal end point identifier (TEI) frame 505, each of which are one octet in length. A control frame 507, is one or two octets in length, and is followed by an information frame 509, which has a variable length between 0 and 128 octets. A frame check sequence frame 511 follows and occupies two octets in length. An end frame 513 serves as an end of setup message flag.
The SAPI frame 503 includes a first subfield xe2x80x9cSAPIxe2x80x9d, that identifies a protocol layer-3 user, as well as subframes C/R and 0, that are used as a predetermined formatting feature of SAPI. The terminal end point identifier frame 505, is used to provide a unique terminal end point identifier that is used to identify the user""s equipment. The control frame 507 defines the type of frame format that will be employed such as an information frame, supervisory frame, and unnumbered frame for example. The information frame 509, includes a variable number of octets varying from 0 to 128 and contains respective subfields that contain any sequence of bits that form an integer number of octets.
Thus, when a user wishes to send data to a destination, information in the information field is passed directly to the destination user without the ISDN switch deciphering the contents of the information. Following the information field 509, the frame check sequence 511 is included and performs an error-detection function by calculating a code from the remaining bits of the frame, exclusive of the flags. The normal code is a cyclical redundancy check code. Finally, the end flag frame 513, includes a specific code indicating the end of the setup message.
As identified by the present inventor, a limitation with the conventional ISDN setup architecture is that there is no suitable approach for arranging a single 128 kbps connection between a source terminal and a destination terminal, by way of the ISDN switch. Nor does the conventional ISDN setup architecture enable the feature of subchannelization, or 1xc3x97N communications as discussed in co-pending Application entitled xe2x80x9cMethod and Apparatus for Sending a 1xc3x97N Communication Messagexe2x80x9d. Because the conventional ISDN switch handles the different B channels independently, the ISDN switch imparts a significant degree of uncertainty regarding the communications paths assigned to different B channels that both have common origins and destinationsxe2x80x94the net result being different, and perhaps non-static, interchannel delay. Conventional bonding and multilink PPP based systems overcome the delay obstacle imposed by the ISDN switch by employing more expensive and complex source and destination equipment so as to accommodate the processing and management overhead for xe2x80x9ccombiningxe2x80x9d two B channels. Furthermore, many conventional ISDN terminals such as G3 facsimile machines, are not configured to communicate over a 128 kbps link, as it is presumed that no more than 64 kbps is available for facsimile transmissions. Neither do conventional ISDN terminals, such as G3 facsimile machines, enable the operation of subchannelization, where channel speeds range from 1 kbps to 128 kbps depending on usage demands/requests.
Accordingly one object of the present invention is to provide a novel method, apparatus and system that provides expanded data rates in ISDN networks and subchannelization of ISDN channels for use in 1xc3x97N messaging that overcomes the above limitations of existing methods, apparatuses and systems.
It is a further object of the present invention to provide a source ISDN terminal configured to transmit a request message to a network switch, indicating that the source terminal requests that the network switch handle one or both B channels as a composite channel for transmission of one or more subchannels having a composite data rate of up to 128 kbps.
It is yet another object of the present invention to provide a method and network switch that establishes the composite channel with subchannelization between the source terminal and one or more destination terminal(s).
These and other objects are achieved with an inventive method, apparatus and system that forms a setup message at a source terminal, a non-exhaustive description of which follows. The setup message includes a request for subchannelization of one or both B channels so as to maximize communication efficiency when sending a 1xc3x97N message to one or more destination facilities, or separate messages to one or more facilities. The source terminal sends the setup message with the request to the switch, where the switch invokes a channel and bandwidth coordination mechanism that subdivides the bandwidth of one or both B channels for communication between the source terminal, and one or more destination terminals. The setup message also indicates whether or not a 1xc3x97N extension message is included.
When a data message is sent to more than one destination facility, a request is made for a desired data rate to be used for each of the destination facilities identified in the setup message. The switch then determines whether both B channels are needed to support the communication request made by the source terminal and determines whether the communication resources are available at the identified destination terminal(s). When one of the destination terminal(s) cannot support the requested communication capacity requested by the source terminal, that destination terminal offers a counter proposal to at least one of the switch and/or source terminal. If the counter proposal is accepted by the source terminal and/or switch, the switch changes the communication speed to that destination terminal. In this way, the communication capacity of one or both of the B channels is optimized when sending either a regular data message or a 1xc3x97N extension message to one or more destination terminals.
A facet of the present invention is the use of a modified ISDN switch, modified to handle two B channels as a single channel, the combined channel capacity of which may be subchannelized based on user requests. The modified switch includes a processor-based channel and bandwidth coordination mechanism configured to determine if a source terminal requests subchannelization of one or both B channels and coordinates the allocation of the available bandwidth from the one or both of the B channels to respective destination facilities identified as recipients of the message(s) from the source terminal.

Smart allocation of bandwidth for multiple independent calls on a digital network


A new and distinct Clematis hybrid named ‘BLUE GLOSS’ is disclosed, characterized by a distinctive silvery violet-blue flowers, and dense, shrubby plant form. Plant habit is well suited for container plantings. Semi-double flowers in Spring (May/June), single flowers August/September. The new cultivar is a Clematis typically suited for ornamental container and landscape use.

The new cultivar is the result of chance discovery in Hoganas Sweden. The inventor is Kjell Bolinder, a citizen of Sweden The new variety was discovered as a single seedling, of unknown parentage. The discovery was made in June 2003.
After selecting and isolating the new cultivar, asexual reproduction of the new cultivar 'BLUE GLOSS' was first performed in Sweden, at a hobbyist nursery by vegetative cuttings in June 2007. 'BLUE GLOSS' has since produced multiple generations, and has shown that the unique features of this cultivar are stable and reproduced true to type.


A surface mountable electrical connector is provided for connecting an electronic component (such as a central processing unit) to a circuit board includes an insulative housing, having a receiving surface for receiving the electronic component, and a mounting surface for attachment to the circuit board. The housing has a plurality of through holes formed therein which extend between the receiving and mounting surfaces. The mounting surface is provided with a plurality of depressions that are sunken toward the interior of the housing and which are disposed proximate to the through holes. Conductive terminals are received within the through holes and free ends of the terminals extend outwardly from the through holes and are bent obliquely toward the depression so that a free end of the terminal is received within the depression to thereby form a mounting portion so that a solder ball can be attached to the mounting portion. A side wall of the depression facilitates the positioning of the solder ball on the mounting portion.

The present invention relates to an electrical connector structure for an electronic product, and more particularly to an electrical connector structure that is surface mountable.
For electronic products that are commonly circulated in the marketplace, consumers would, aside from expecting them to achieve specific functions, particularly demand that they have various shapes and light weight. In order to have various shapes and light weight, the internal electronic components of the electronic products have to be developed in the direction of compactness, and how to connect an electrical connector and a circuit board in a compact manner is an important subject. A conventional way of connecting an electrical connector and a circuit board is to form holes in the circuit board. That is, terminals of the electrical connector pass through through holes which are formed in the circuit board, and which are fixedly connected to corresponding contacts on the circuit board distal to the electrical connector. However, in such a connecting method, the through holes in the circuit board take up a large percentage of the wiring area of the circuit board, which is undesirable. Therefore, it becomes a problem to be solved as to how an electrical connector can be connected to a circuit board without forming holes in the latter.
At present, there are available circuit boards that are not provided with through holes, and wiring is conducted on a surface of the circuit board which is proximate to the electrical connector. The corresponding contacts on the circuit board are directly connected to the terminals of the electrical connector via solder balls after heating the latter, thereby establishing electrical connections. FIG. 1 illustrates such a known connector and shows the relative relationship among an electrical connector 7, an electronic component 6 and a circuit board 8. FIG. 2 is a sectional view taken along line Axe2x80x94A of FIG. 1, and illustrates a surface 82 of the circuit board 8 that is proximate to the electrical connector 7 is provided with corresponding contacts 84. A plurality of terminals 78 of the electrical connector 7 are each disposed in respective single through holes 76 in an insulating housing 70, with the end portions 782 of the terminals 78 slightly extending past a surface 72 of the insulating housing 70. A solder ball 71 is pre-planted in the terminal end portion 782. The electrical connector 7 with the pre-planted solder balls 71 is then brought near the circuit board 8 such that the solder ball 71 attached to each terminal end portion 782 is in contact with the corresponding contact 84 on the circuit board 8. After heating, the electrical connection is established.
Further, in another known electrical connector, as disclosed in R.O.C. Patent Publication No. 383963 and as illustrated in FIG. 3, each of a plurality of through holes 76 formed in an insulating housing 70 of an electrical connector 7 has one end located proximate to a circuit board 8 and configured to have a spherically curved matching surface 762. Each of a plurality of terminals 78 has an end portion 782 with a side surface 784 that follows the spherically curved matching surface 762, and the two of which cooperatively define a receiving space for receiving a solder ball 71, with the terminal side surface 784 in contact with the solder ball 71. After heating, the terminals and the circuit board are fixedly connected to achieve electrical connection.
Still further, in the electrical connector disclosed in R.O.C. Patent Publication No. 389430 and illustrated in FIG. 4, an electrical connector has a plate-like insulating housing 70 that is provided with a plurality of through holes 76. The edges of the through holes 76 which are proximate to a circuit board 8 are configured to have respective interior, recessed surfaces 764, the profile of which matches the shape of the solder ball 71. A plurality of terminals 78 are inserted into the through holes such that end portions 782 thereof respectively and slightly project in a straight direction from the interior recessed surfaces 764 of the through holes and contact with the solder balls 71. After heating, the terminals and the circuit board are fixedly connected to thereby establish electrical connection.
The present invention provides an improved electrical connector that utilizes solder balls as a means of connection, and which results in improved retention of the connector terminals and solder balls, as well as reduced operating height of the connector.
It is therefore a general object of the present invention to provide an improved electrical connector that reduces the distance between a mounting surface of an insulating housing and a circuit board so as to reduce the overall height after assembly, thereby achieving the object of compactization of electronic products.
Another object of the present invention is to provide an electrical connector which maintains the spherical shape of solder balls before and after soldering so as to obtain good connection with terminals and good electrical conductivity after connection.
A further object of the present invention is to provide an electrical connector that enables easy positioning and confinement of the solder balls and to avoid the drawback of poor electrical conductivity after soldering, which results from displacement of the solder balls caused by non-uniform expansion and contraction of the terminals and the circuit board during the soldering and heating process due to difference in the materials of the terminals and the circuit board.
The electrical connector of the present invention mainly provides an electrical connection between an electronic component (such as a central processing unit) and a circuit board. The present invention is characterized in that a depression is formed in one lateral edge of a mounting surface of an insulating housing of the electrical connector adjacent to a through hole, and that one end of a terminal extends through an opening of the through hole, bends, and is positioned in the depression to thereby form a mounting portion for attachment of a solder ball thereto. The structure includes: an insulating housing, the insulating housing having a receiving surface for receiving an electronic component, and a mounting surface disposed to be proximate to the circuit board, a plurality of terminal through holes being disposed between the receiving surface and the mounting surface, the mounting surface being provided with depressions each of which is adjacent to an opening of a respective one of the through holes and is sunken toward the interior of the insulating housing; and a plurality of conductive terminals respectively disposed in the through holes such that when a respective one of the terminals is disposed in the respective through hole, a free end thereof extends outwardly of the opening of the respective through hole in the mounting surface and bends obliquely toward the depression so that the free end of the terminal is located in the depression to form a mounting portion and so that the solder ball is confined between the mounting portion and a side wall of the depression and can thus be positioned. The spherical shape of the solder ball and good connection can therefore be maintained. Furthermore, as the depression is sunken into the interior of the insulating housing, the distance between the circuit board and the insulating housing after soldering can be reduced to thereby reduce the height of the assembly of the circuit board and the electrical connector.
The technical means employed by the present invention in order to achieve the aforesaid objects and features, and the effects of the invention are described hereinafter by way of the preferred embodiments with reference to the accompanying drawings, in which like reference numerals identify like parts.


The invention relates to a method of estimating a propagation channel, between a source transmitting data and a receiver, using at least one learning sequence which comprises symbols referred to as “pilot symbols” and which is known to the receiver, so as to decode a data signal (digital signal), the signals being sent in successive frames, each frame being partitioned into a specified number of time slots.

1. Field of Invention
The present invention relates to a method and a device for estimating the parameters of a propagation channel, so as to decode digital signals, by using a learning sequence or reference sequence known to the receiver. The signals are sent in successive frames, each frame being partitioned into a specified number of time slots.
The invention applies for example for demodulating a broadband or spread spectrum digital signal.
The invention finds its application in the field of cellular networks operating on the "CDMA" principle (the abbreviation standing for Code Division Multiple Access), such as the networks based on the IS95 standard which has been in service for several years in the USA, or else those based on the UMTS standard (the abbreviation standing for Universal Mobile Telecommunication System) which ought to be operational in Europe at least by the year 2002. It applies in particular within the framework of mobile radio communications.
The method according to the invention can without departing from the scope of the invention be applied to propagation channels of any nature.
2. Description of Related Art
In a CDMA system all the users share the same band and use waveforms which are spectrally spread with the aid of codes, each user having his own code.
By way of indication, a description of such a system can be found in one of the following references:    [2] W.C.Y. LEE, "Overview of cellular CDMA", IEEE Transactions on vehicular technology, vol. 40, No. 2, May 1991 or    [3] R. L. PICKHOLTZ, D. L. SHILLING and L. B. MILSTEIN, "Theory of spread-spectrum communications—A tutorial", IEEE Transactions on communications, vol. com-30, No. 5, pp 855–884, May 1982.
The principle of direct sequence spread spectrum is to chop a useful bit of duration T into NG pulses or chips of duration T′=T/NG. The band W′ of the resulting signal is thus NG times larger than that of the useful signal W, thereby theoretically allowing NG times as large a modulation rate. The pulse sequences or codes, are generally pseudo-random sequences (PN sequences), designed to have particular autocorrelation and cross-correlation properties (ideally, the autocorrelation is pulse-like and the correlations between codes are zero). Such sequences are described for example in the two works: [1]: J. G. PROAKIS, "Digital communications", McGraw Hill and the aforesaid reference [2].
On reception, each user (or transmission channel) is demodulated by an operation of correlation with its spreading code, known to the receiver. This processing is a matched filtering which imparts a reception gain equal to the ratio of the spread band to the initial useful band represented in FIG. 1.
The CDMA concept allows not only multiple access (large combinatorial offered by pseudo-random codes, for allocating a different code to each user) but also increased robustness to scrambling (intentional or otherwise) and to poor propagation conditions (multipaths, fading, etc).
At present, it is known to use a spectrally spread waveform in order to effectively counter the phenomenon of multipaths (this phenomenon occurs for various propagation channels and in particular for the mobile radio channel) and even to profit therefrom in order to combat fading (random variations in the amplitude and phase of the signal).
Specifically, if Tm is the temporal spreading of the channel and if W is the bandwidth of the signal transmitted, then it is theoretically possible to isolate in reception TmW components (a bandwidth W makes it possible in reception, by correlation, to isolate paths with a temporal resolution equal to 1/W), which correspond physically to the various propagation paths. All or some of these components are independent and it is possible to recombine them in such a way as to increase or maximize the signal-to-noise ratio. A diversity effect is thus obtained, exploiting the statistical independence of the various propagation paths making up the signal received.
This diversity technique was initially proposed by Price and Green in 1958 who gave the name RAKE receiver to the optimal processing (the receiver isolates each path and then undertakes a recombination, hence the analogy with a garden rake). This processing, which coherently sums all the paths, consists simply of a filtering matched to the signal received, that is to say matched to the channel (it may be shown that this processing is optimal provided one considers the reception of a single user or code, all the other users constituting noise possessing the property of being white and gaussian).
In this regard, reference may be made for example to the work "Digital communications" published by McGraw Hill and authored by J. G. Proakis.
The implementation of the RAKE receiver therefore assumes that the impulse response of the channel, that is to say the complex amplitudes of all the paths, is known. In practice, it is possible to employ an estimate of these amplitudes which takes account of the various characteristics of the propagation channel (temporal spreading, fading) and in particular of its various scales of fluctuation (fast fading and slow fading).
On the mobile radio channel, two scales of variation of the propagation characteristics are generally distinguished, described for example in the work authored by D. Parsons and published by Pentech Press in 1992 under the title "The mobile radio propagation channel".
The first scale corresponds to fast fading (or Rayleigh fading), which induces a variation in the amplitudes and phases of the paths after a time of the order of the channel coherence time (the inverse of the Doppler band of the channel). In the mobile radio context, this decorrelation time (time interval for which two realizations of the complex amplitude of a path are decorrelated) corresponds to an advance of the mobile of the order of half the wavelength of the carrier frequency reference [4], On this timescale, the delay times of the paths are constant.
The second scale of fluctuation corresponds to slow fading (or long-term fading), due to the masking effects and to the changes of environment. This phenomenon induces on the one hand a modification of the average power of the paths, and on the other hand a significant alteration in the delay times of the paths; some paths are also liable to appear and others to disappear.
The decorrelation time (or the decorrelation distance) associated with slow fading depends on the channel, that is to say on the type of environment in which the mobile is deploying. In practice, this decorrelation time is markedly greater (at least an order of magnitude) than that associated with fast fading. For example, the ETSI within the framework of UMTS, indicates a slow fading decorrelation distance, for an urban environment, of around 20 meters; this leads to a ratio of around 300 (20/(λ/2) with λ=c/f and f=2 109 Hz) between the long-term and short-term decorrelation times.
The subject of the invention relates to a method allowing dynamic estimation of the propagation channel, taking account of the various fluctuations alluded to above, with the aim of demodulating a digital signal.
The method is applied in particular in the following cases:                Single-user reception, that is to say when interested in the demodulation of just one user, all the others being regarded as noise (no joint detection or multiuser detection);        Transmission of a reference sequence, in addition to the useful data, which is dedicated to the estimation of the propagation channel;        The propagation channel is fluctuating;        The temporal spreading of the channel is less than the duration of a useful bit. Thus, the inter-symbol interference can be neglected and the implementation of an equalizer downstream of the RAKE receiver is not necessary. Each bit or useful symbol is demodulated independently of the other bits or useful symbols;        The channel can be regarded as constant over the duration of a bit or useful symbol (Tcoherence>>T, where Tcoherence is the channel coherence time).
The word "symbol" designates a unit of information, the expression "learning symbol" or "pilot" corresponds to a unit of information of the known signal.

Method and device for estimating a propagation channel

Abstract: It comprises at least the following steps:                a) choosing a search window, estimating the complex amplitude and the energy of each predominant path k situated in the search window over the duration of each of the time slots and demodulating the data bits (useful bits),        b) updating the energy of each possible path of the search window every K slots,        c) selecting every K*L slots, the energy paths k which are predominant.        d) Application to the demodulation of a signal of CDMA type, or of UMTS type.


In a telecommunication network, the power of a first signal transmitted via a satellite by a first station to be received in the form of a second signal by a second station is regulated. At a given time, a value representative of a signal-to-noise ratio of the second signal is predicted for a later time, and, at an intermediate time, the power of the first signal is regulated in the first station as a function of the predicted value. The intermediate time precedes the later time by a time period substantially equal to the propagation time between the first and second stations.

1. Field of the Invention
The present invention is generally concerned with satellite telecommunication networks. To be more precise, the invention concerns a method of regulating the power of a first signal transmitted via a satellite from a sending or first station to be received in the form of a second signal by a receiving or second station.
2. Description of the Prior Art
The radio communication channel set up between two stations in a satellite telecommunication network causes variation in both (a)--the received signal level and (b)--the received noise level at the receiving station. The variation in the received signal level is due to the characteristics of the channel. It is the result of fading due to the presence of obstacles, for example, or multiple propagation paths conveying signal components that combine incoherently with the main component of the transmitted signal. The variation in the received noise level is also due to the characteristics of the channel, as with the signal. It can also be the result of variations in the power of the noise source. Thus the signal, so-called first signal, which is transmitted by the sending or first station is transformed into a signal, so-called second signal, when received by the receiving station or second station.
The quality of the link set up through the channel deteriorates if nothing is done to remedy this problem of variation in the received signal components.
A simple solution is to allow a priori for the maximal fluctuations to which the received signal may be subjected. The sending station then sends with a power margin that guarantees the quality of the link regardless of the propagation and interference environment associated with the channel. This solution leads to overrating of the transmission system, to a loss of capacity and to overrating of the power transmitted by the stations.
In the context of land mobile networks, the fluctuations of the signal and noise components in the channel are considerable, possibly as much as several tens of dB, and occur at very high speed. Control or regulation of the power at which the signal is transmitted by the sending station is therefore restricted to correcting the average attenuation of the channel.
A prior art "closed loop" method of controlling the power of a signal transmitted by a sending station is based on the following principle: the receiving station measures the signal-to-noise ratio of the signal received from the sending station. The measured signal-to-noise ratio is sent from the receiving station to the sending station in the form of a message. The latter station corrects the power level of the transmitted signal according to the measurements carried out by the receiving station. The application of this method to the satellite networks mainly used until now, namely networks using satellites in geostationary orbit at an altitude of about 36 000 kms, would seem to be of only limited benefit. In any network of this kind, the round-trip propagation time for a signal between the sending and receiving stations is substantially equal, ignoring processing times, to the reaction time of the power regulation system, which separates the time of transmission of data by the sending station from a subsequent time of correction of the power at which data is transmitted on the basis of measurement of the received signal. For a satellite at around 36 000 kms, the reaction time of the power correction system is approximately 500 ms, which imposes an absolute limit on the possible correction of variations in components of the signal to frequencies below (1/0.5)=2 Hz. In practise, given the limitations due to the system, this range can be deemed to have an upper limit of 1 Hz.
The prior art therefore provides no effective method of power control using a "closed loop" type method. A first object of the invention is therefore to provide a method of this kind that is particularly suitable for radiocommunication networks using non-geostationary satellites in low Earth orbit. Nevertheless, the method is applicable to networks using satellite(s) in circular intermediate orbits, geostationary orbits, elliptical orbits, etc. A second object of the invention is to provide a set of two stations for implementing the method of the invention. Still another object of the invention is to provide stations for carrying out the method.

Method of regulating the power of a signal transmitted by a first station to a second station in a satellite telecommunication network


An organic electroluminescent device comprising: a pair of electrodes; and at least one organic compound layer between the pair of electrodes, the at least one organic compound layer including a light emitting layer, wherein the light emitting layer contains at least one host material and at least one luminescent material, and the host material is a compound represented by the formula (I) as defined herein.

OELDs have been actively studied and developed because of their capabilities of emitting light of high brightness at a low driving voltage. An OELD generally comprises a pair of opposing electrodes having therebetween a light emitting layer or a plurality of organic layers including a light emitting layer. With an electric field applied to the opposing electrodes, electrons and positive holes are injected from the cathode and the anode, respectively, into the light emitting layer, where they are recombined to form excitons, which emit light. Otherwise, energy is transferred from the excitons to create excitons of other molecules, which emit light. The light thus emitted from the light emitting layer is utilized to display an image.
For the purpose of improving driving durability of OELDs, it has been proposed to use a metal complex as a host material in the light emitting layer as disclosed, e.g., in JP-A-2002-305083. There still has been room for further improvement on efficiency and durability.


The present invention relates to compounds of the formula I EQU [CH.sub.3 --(CH.sub.2).sub.29 --O--].sub.m --R (I). wherein. if m stands for 1, then PA1 R represents a group derived from a mono- or di- or oligosaccharide by removing the hydrogen atom from the hydroxyl group being in the 1(alpha) or 1(beta) position, or the O-protected, preferably acetylated derivative thereof, PA1 if m stands for 2, then PA1 R represents a group derived by removing a hydrogen atom attached to the carbon atom being in position 1 of the reaction product of glucose and mono-, di- or triethylene glycol or the O-protected, preferably O-acetylated derivative thereof.

1-Triacontanol, the primary alcohol having 30 carbon atoms, was separated and identified by Chibnall in 1933.
According to U.S. Pat. No. 4,150,970, 1-triacontanol is a growth regulator for plants. This activity is also supported by Science, Vol. 195, pages 1339 to 1341.
According to published European patent application No. 78,533 a topical pharmaceutical composition comprising 1-triacontanol as active ingredient is useful for treating skin disorders.
No reference has been made so far to the different sugar derivatives of 1-triacontanol.
The use of 1-triacontanol and the examination of the mechanism of its activity is very difficult as this compound is highly lipophylic and hardly dissolves in water.


A load sensing control system for a hydraulic machine sets a variable target differential pressure between a delivery pump pressure and a load pressure of an actuator. A control factor is determined that becomes larger as the deviation between the target differential pressure and the actual differential pressure is increased, and that becomes smaller as the differential pressure deviation is decreased. The control factor also becomes larger as the target differential pressure becomes smaller. The target displacement volume for the hydraulic pump is based on the differential pressure deviation, which is calculated from the target differential pressure and the control factor.

Hydraulic drive circuits for use in hydraulic machines such as hydraulic excavators and cranes each comprise at least one hydraulic pump, at least one hydraulic actuator driven by a hydraulic fluid delivered from the hydraulic pump, and a flow control valve connected between the hydraulic pump and the actuator for controlling a flow rate of the hydraulic fluid supplied to the actuator. It is known that some of those hydraulic drive circuits employ a technique called load sensing control (LS control) for controlling the delivery rate of the hydraulic pump. The load sensing control is to control the delivery rate of the hydraulic pump such that a delivery pressure of the hydraulic pump is held higher by a fixed value than a load pressure of the hydraulic actuator. This causes the delivery rate of the hydraulic pump to be controlled dependent on the load pressure of the hydraulic actuator, and hence permits economic operation.
Meanwhile, the load sensing control is carried out by detecting a differential pressure (LS differential pressure) between the delivery pressure and the load pressure, and controlling the displacement volume of the hydraulic pump, or the position (tilting amount) of a swash plate in the case of a swash plate pump, in response to a deviation between the LS differential pressure and a differential pressure target value. Conventionally, the detection of the differential pressure and the control of the tilting amount of the swash plate have usually been carried out in a hydraulic manner as disclosed in JP, A, 60-11706, for example. This conventional arrangement will briefly be described below.
A pump control system disclosed in JP, A, 60-11706 comprises a control valve having one end subjected to the delivery pressure of a hydraulic pump and the other end subjected to both the maximum load pressure among a plurality of actuators and the urging force of a spring, and a cylinder unit operation of which is controlled by a hydraulic fluid passing through the control valve for regulating the swash plate position of the hydraulic pump. The spring at one end of the control valve is to set a target value of the LS differential pressure. Depending on the deviation occurring between the LS differential pressure and the target value thereof, the control valve is driven and the cylinder unit is operated to regulate the swash plate position, whereby the pump delivery rate is controlled so that the LS differential pressure is held at the target value. The cylinder unit has a spring built therein to apply an urging force in opposite relation to the direction in which the cylinder unit is driven upon inflow of the hydraulic fluid.
However, the above conventional control system for the hydraulic pump has had the following problem.
In the conventional pump control system, the tilting speed of a swash plate of the hydraulic pump is determined dependent on the flow rate of the hydraulic fluid flowing into the cylinder unit, while that flow rate of the hydraulic fluid is determined dependent on both an opening, i.e., a position, of the control valve and setting of the spring in the cylinder unit and, in turn, the position of the control valve is determined by the relationship between the urging force of the LS differential pressure and the spring force for setting the target value. Here, the spring of the control valve and the spring of the cylinder unit each have a fixed spring constant. Accordingly, a control gain for the tilting speed of the swash plate dependent on the deviation between the LS differential pressure and the target value thereof is always constant. The control gain, i.e., the spring constants of the two springs, are set in such a range that change in the pump delivery pressure will not cause hunting and the pump is kept from coming into disablement of control on account of change in the delivery rate upon change in the swash plate position.
In the LS control, the delivery pressure of the hydraulic pump is determined dependent on a difference between the flow rate of the hydraulic fluid flowing into a line, extending from the hydraulic pump to the flow control valve, and the flow rate of the hydraulic fluid flowing out of the line, as well as a line volume into which the delivered hydraulic fluid is allowed to flow. Therefore, when the operation (input) amount of the flow control valve (i.e., the demanded flow rate) is small, the opening of the flow control valve is so reduced that the small line volume between the hydraulic pump and the flow control valve plays a predominant factor. As a result, the delivery pressure is largely varied even with a slight change in the flow rate upon change in the swash plate position. On the other hand, when the operation amount of the flow control valve is increased to enlarge the opening thereof, the large line volume between the pump and an actuator now takes part in the pressure change, whereby change in the delivery pressure upon change in the delivery rate is reduced.
Accordingly, in order to reliably perform the LS control over a range of the entire operation amount (opening) of the flow control valve without causing hunting, the above-mentioned control gain, i.e., the spring constants of the two springs, are set to a relatively small value such that a tilting speed of the swash plate to prevent the pressure change from hunting at the small opening of the flow control valve is provided.
Meanwhile, when a control lever is operated, the operator tends to operate the control lever at a speed corresponding to the speed change demanded for the actuator. With the operating speed of the control lever being small, the difference between the demanded flow rate of the flow control valve and the delivery rate of the hydraulic pump is small, and so is a deviation between a differential pressure signal, determined from the pump delivery pressure and the maximum load pressure, and the target differential pressure set by the spring. In this case, because the operating speed of the control lever is small, the control gain set by the two springs as mentioned above can provide sufficient change in the tilting speed of the swash plate, i.e., the sufficient delivery rate of the hydraulic pump, to realize demanded speed change of the actuator.
However, when the operating speed of the control lever is large, i.e., when the control lever is operated abruptly, there occurs a large difference between the demanded flow rate of the flow control valve and the delivery rate of the hydraulic pump, which also increases the deviation between the differential pressure signal, determined from the pump delivery pressure and the maximum load pressure, and the target differential pressure set by the spring. In this case, with the control gain set by the two springs as mentioned above, the tilting speed of the swash plate, i.e., change in the delivery rate of the hydraulic pump, is limited and becomes insufficient. Accordingly, the demanded speed change of the actuator cannot be realized, causing the operator to feel that the actuator is too slow in action.
To solve the above problem, therefore, the present inventors have proposed in International Application No. PCT/JP90/00962 (International Application Date: Jul. 27, 1990; International Laid-Open No. WO91/02167; International Laid-Open Date: Feb. 21, 1991) a control system for a hydraulic pump characterized in comprising first means for determining, based on a delivery pressure of a hydraulic pump and a maximum load pressure among a plurality of actuators, a target displacement volume (a tilting amount of a swash plate) of the hydraulic pump to reduce a differential pressure deviation between the above differential pressure and a preset target differential pressure, second means for determining a control gain of the first means to becomes larger with the differential pressure deviation increasing and smaller with the differential pressure deviation decreasing, and third means for controlling displacement volume varying means (swash plate) of the hydraulic pump so that the displacement volume of the hydraulic pump is matched with the target displacement volume determined by the first means.
With the above arrangement, in a range where the operating speed of the control lever is small and so is the differential pressure deviation, the control gain determined by the second means also becomes small to reduce the tilting speed of the swash plate. This enables stable control in which there occurs no hunting due to abrupt change in the delivery pressure. On the other hand, when the operating speed of the control lever is large, i.e., when the control lever is operated abruptly and the differential pressure deviation is increased, the control gain determined by the second means also becomes large to raise the tilting speed of the swash plate, thus enabling a response that is not slow but prompt. By so doing, the delivery pressure of the hydraulic pump can always be controlled in an optimum way regardless of the operating speed of the control lever.
The present invention is intended to further improve the above prior application and solve the problem encountered in the case of making the target differential pressure variable.
More specifically, while the target differential pressure between the pump delivery pressure and the maximum load pressure is usually set constant in the load sensing control, it has been proposed to make the target differential pressure variable for various purposes. One example is disclosed in JP, A, 2-76904. In this proposed technique, the target differential pressure can be changed externally for the purpose of facilitating fine speed operation of an actuator. By setting the target differential pressure to a small value, the displacement volume of the hydraulic pump is controlled so as to keep the small target differential pressure. As a result, since the differential pressure across the flow control valve also becomes small by being restricted by the small target differential pressure, metering characteristics of the flow control valve are changed to reduce the flow rate of the hydraulic fluid supplied to the actuator and the fine speed operation of the actuator can easily be realized.
In the case of making the target differential pressure so variable, however, at the small target differential pressure, the differential pressure deviation cannot exceed the target differential pressure and the differential pressure deviation is also limited to a small maximum value, leading to that when the operating speed of the control lever is large, i.e., when the control lever is operated abruptly, there can be obtained only a limited small differential pressure deviation. Accordingly, even if the control gain is set dependent on the differential pressure deviation as with the foregoing prior application, the obtained control gain is small and the tilting speed of the swash plate is so limited that the actuator is forced to move slowly.
An object of the present invention is to provide a control system for a hydraulic pump which, when a target differential pressure for load sensing control is set as a variable value, can perform stable control at a small operating speed of the control means without causing hunting and achieve a response, not slow but prompt, at a large operating speed of the control means, no matter what the value of the target differential pressure.

Load sensing control system for hydraulic machine

Hitachi Construction Machinery Co., Ltd.


An automatic tennis ball supply device, includes: a spring for transmitting the power via its elasticity; a first shaft which is joined to part "b" which is the first part of a steel band of the spring; a handle for winding the spring; a first gear which rotates in the same direction as the first shaft; a second gear which rotates to the left when the wound spring runs down; a latch for disengaging the first and second gears from each other when the spring is wound, and for engaging the first and second gears with each other when the wound spring runs down; a third gear which rotates to the right, when the second gear rotates to the left; a second shaft which rotates in the same direction as the rotating third gear; a rotative speed control unit for controlling a rotative speed of the second shaft; a ball pick up unit for picking up and conveying one of the plural tennis balls in a container; a ball guide unit for guiding the tennis ball to outside. The automatic tennis ball supply device of the present invention, is given the power generated by the spring which is wound and then runs down, and thus picks up the plural tennis balls in the container one by one, before supplying the ball to the user, for user's tennis posture practice. Therefore, it is convenient to automatically supply the balls, instead of other people's throwing the balls to the user directly.

1. Field of the Invention
The present invention relates to an automatic tennis ball supply device. More particularly, it relates to an automatic tennis ball supply device, which picks up a plurality of tennis balls in a container one by one, by means of the power generated by a spring which winds and thereafter runs down, before supplying the tennis ball to a user, for user's posture practice.
2. Discussion of Related Art
A conventional automatic tennis practice mechanism is employed to shoot at a high speed a tennis ball to a user, using the force caused by the air which is compressed and thereafter discharged, before struck by the user. This mechanism is adequate for an expert at playing tennis to improve his ability. But it is not proper for children or beginners to learn to posture at an early stage, and there is a problem that other people should directly throw tennis balls to the user.
In addition, the automatic tennis practice mechanism which is about 80.about.90 kilograms in weight, and fairly large-sized, has the problems that it is not convenient for the user to move it to another place, it is hard to purchase it for home use due to its high price, we should quit practicing playing tennis when the electric power of a charging battery is discharged, and the use of electricity of 110V and 220V causes a loss of power.


A protective garment for a fire fighter or emergency worker is provided. The protective garment includes an outer shell and a drag harness located at least substantially within the outer shell. The drag harness includes a wearer portion, a gripping portion and a flap operably coupled to the gripping portion. The flap is releasably secured to the outer shell in a stored state. The flap and the gripping portion remaining operably coupled to one another and extend away from the outer shell in a deployed state to drag a wearer.

Commonly, a firefighter or an emergency worker wears a protective garment, such as a protective coat. Furthermore, firefighters or emergency workers also wear additional safety equipment, such as drag harnesses, such that the wearer can be dragged and/or carried by a rescuer should the wearer become incapacitated. These drag harnesses can be worn within or on the exterior of the of the protective garment.
Protective garments and drag harnesses have generally been configured to have a pull strap located behind the head of the wearer. In this form, the pull strap can be extended from the protective garment to drag the wearer should the wearer become injured or incapacitated. However, the drag harness is susceptible to catching on or becoming abraded by external surfaces. Therefore, drag harnesses may be located completely within the protective garment and/or covered by pockets or flaps. However, the drag harness must still be capable of being grasped quickly in an emergency situation. Furthermore, the rescuer is generally wearing bulky gloves which provide diminished tactile feedback.

Protective garment and drag harness with flap


In a database system, a full outer join is computed using a hash-based join.

Relational and object-relational database management systems store information in tables of rows in a database. To retrieve data, queries that request data are submitted to a database server, which computes the queries and returns the data requested.
Queries submitted to the database server must conform to the syntactical rules of a particular query language. One popular query language, known as the Structured Query Language (SQL), provides users a variety of ways to specify information to be retrieved.
A query submitted to a database server is evaluated by a query optimizer. Based on the evaluation, the query optimizer generates an execution plan that defines operations for executing the query. Typically, the query optimizer generates an execution plan optimized for efficient execution. The optimized execution plan may be based on a rewrite of the query.
A query may specify a full outer join operation based on join condition between two tables, a left table and a right table. A full outer join joins every row in the left table with every row in the right table that satisfies the join condition. A full outer join also returns a row for each row in the left table that did not satisfy the join condition with any row in the right table, and returns a row for any row in the right table that did not satisfy the join condition with any row in the left table.
The following tables are used to illustrate a full outer join.
TABLE EMPROW #DEPTNODNAME110SALES230MARKET
TABLE DEPTROW #EMPNOENAMEDEPTNO1100ALLEN102101CLARK20
A full outer join between left table DEPT and right table EMP, based on an equijoin join condition involving columns DEPTNO in DEPT and DEPTNO in EMP, returns the following result set.
ROW #EMPNOENAMEEMP.DEPTNODEPT.DEPTNODNAME1100ALLEN1010SALES2101CLARK20NULLNULL3NULLNULL3030MARKET
In the result set, row 1 represents a join between row 1 of EMP and row 1 of DEPT. Row 2 is a "right" outer join row because it was returned for a row which did not satisfy the join condition with any row from the left table. Row 2 in particular represents row 2 of EMP. Note the columns of the left table contain NULL. In this case, DEPT.DEPTNO and DNAME of table DEPT contains NULL.
Row 3 is a "left" outer join row for row 2 in table DEPT, which did not match any row from right table EMP.
Described herein are techniques for efficiently computing full outer joins between tables. The term table refers generally to any set of rows or tuples such as those stored in a database table or computed for an expression, such as a query or subquery. For example, the rows in the result set above can be referred to as a table.


An ink composition includes a self-dispersible coloring agent that includes an ionic group and a non-ionic linear or cyclic ester or amide moiety on a surface of the coloring agent at a mole ratio of about 1:10 to about 10:1, an organic solvent, and water. The coloring agent has a modified surface, so that stability of the ink can be increased due to an interaction between the coloring agent and the organic solvent, the particle size of the coloring agent can be kept uniform, an adhering force with respect to a substrate is increased to minimize bleeding between colors of a printed image, waterfastness and rubfastness in dry and wet conditions are increased to obtain an excellent colorfastness, and resulting in a high quality printed image and an excellent storage stability.

1. Technical Field
The present general inventive concept relates to an ink composition, and more particularly, to an ink composition that includes a coloring agent with a modified surface to improve stability, thus having uniform particle size and stronger adhesion to paper.
2. Description of the Related Art
A coloring agent is generally defined as a material that exhibits a unique color by selectively absorbing or reflecting visible light. Coloring agents can be divided into dyes and pigments.
A dye is a coloring agent that is printed onto and absorbed by a material, such as fiber, leather, fur, paper, or the like, so that the printed material has excellent color fastness to solar cleaning, rubfastness, and the like. On the other hand, a pigment is a micro particle having a coloring agent, and is not directly absorbed by but rather adhered to a surface of a material using a physical method, such as adhesion or the like, so that the printed material has a unique color. At this time, the unique color of the coloring agent, such as a pigment or a dye, corresponds to a portion of the visible light of 3000 to 7000 Å selectively reflected or absorbed by the coloring agent.
In a method of manufacturing a pigment-type ink, a pigment including a coloring agent must be dispersed in a solvent. As a result, the dispersion of the pigment is mainly dependent on a size distribution and distribution stability of the pigment particles. In addition, in order to prolong a shelf life span of the pigment-type ink, aggregation or precipitation of the pigment particles must be prevented over a long time and under varying ambient conditions, such as temperature.
Typically, a pigment-type black ink contains carbon black as the coloring agent. The carbon black can be dispersed in an ink solvent using a dispersing agent. U.S. Pat. No. 3,687,887 discloses a method of dispersing carbon black in a solvent using a stylene-maleic acid anhydride copolymer, and U.S. Pat. No. 4,697,794 discloses a method of dispersing carbon black in a solvent using a hydrophilic polymer dispersing agent including an ionic group, such as carboxylic acid, sulfonic acid, sulfate, and the like.
The carbon black can also be dispersed using a commercially available dispersing agent, which can be easily obtained. However, when a water-soluble dispersing agent is used to disperse the carbon black pigment in a water-soluble medium, an excessive amount of the water-soluble dispersing agent is required to effectively disperse the pigment, because the water-soluble dispersing agent is physically adsorbed to a surface of the carbon black. The amount of water-soluble dispersing agent needed is comparable to the amount of pigment to be dispersed, and results in poor dispersion efficiency. Also, even though the dispersing agent is bound to the pigment, the bonding is ineffective and unstable, and thus, stable dispersion cannot be obtained. As a result, ink including the dispersing agent cannot be stored for a long time, and the aggregation or precipitation of non-soluble particles may occur in the ink.
A block copolymer and a graft copolymer can be used as a dispersing agent. In this case, however, manufacturing costs are high. When a common surfactant is used, excessive bubbles can be generated in a dispersing operation.
In order to overcome these problems resulting from the use of the dispersing agent and the surfactant, the surface of the carbon black can be modified for dispersion. According to U.S. Pat. Nos. 5,630,868 and 5,672,198, the carbon black pigment can be transformed into a self-dispersible coloring agent by introducing an ionic group to the surface of the carbon black thorough a reaction between the carbon black pigment and a diazonium salt. In order to produce a self-dispersible coloring agent for an ink composition, in particular, a self-dispersible pigment, a cation group, such as a tertiary ammonium group (—NR3+), a tertiary phosphonium group (—PR3+) and a tertiary sulfonium group (—SR2+) where R is a C1-C10 alkyl group or a hydrogen atom can be bound to the surface of the carbon black. The self-dispersible coloring agent can also be made by introducing an anionic component, such as —COOM, —SO3M, —SO2NH2, —PO3HM, —PO3M2 where M is a hydrogen atom, an alkali metal, ammonium, and an organic ammonium, to the surface of the carbon black (U.S. Pat. Nos. 5,630,868 and 5,672,198).
Examples of commercially available self-dispersing pigments include pigments obtained from CABOT Inc. and Orient Inc.
An ink composition using a self-dispersible coloring agent has excellent dispersing properties without needing a dispersing agent, due to the ionic group of the self-dispersible coloring agent. However, the water resistance of the ink composition is decreased due to its high ionic properties with respect to water. In order to overcome this problem, a non-ionic group can be included in the ink composition in addition to the ionic group.

Ink composition including surface modified coloring agent


A femto cell base station includes a generating part that generates a SIP message including a terminal ID of a radio terminal and a check request for the terminal ID at a predetermined time, and a first transmitting part that transmits the SIP message generated by the generating part to a higher level apparatus in the communication system.

In general, in a 3G (third generation) network provided as a public mobile communication network that establishes call connections among cellular phones or other UEs, a subscriber ID (IMSI: international mobile subscriber identity) for identifying a subscriber and a terminal ID (IMEI: international mobile equipment identifier) for identifying a radio terminal are set.
The IMEI is a unique value including information for identifying the UE, such as a serial number, as shown in FIG. 1.
The IMSI is stored in a subscriber identity module, such as a USIM (universal subscriber identity module) card, and the UE is activated by putting the subscriber identity module to the UE.
A system for the existing 3G network checks the IMEI by a MSC (mobile switching center) transmitting the IMEI acquired from the UE to an equipment identify register (EIR: equipment identify register) (see Patent Literature 1, for example).
The IMEI check is intended to check for an IMEI of a radio terminal used in an unauthorized manner, such as an IMEI of a radio terminal stolen and used in an unauthorized manner with a legitimate IMSI, thereby preventing unauthorized use of the radio terminal.
Besides, the possibility of a femto cell that establishes a connection to a mobile communication core network via a wired line installed in a household or office is attracting increasing attention in recent years.
The femto cell is configured so that a femto cell base station (femto AP) that achieves a small coverage of several tents of meters in radius establishes a radio connection among UEs. Typically, the femto cell achieves an indoor coverage, such as a coverage in a household or office. Therefore, a necessary coverage can be achieved without an extra cost of infrastructure construction of the existing macro cell base station (see Patent Literature 2, for example).

Communication system for checking for unauthorized use of a terminal


An assembly, system, and method for identifying defects in a structure are provided. The assembly includes a structure of a metallic or composite material, and a flexible sheet of material positioned adjacent to the structure. The assembly also includes a plurality of non-destructive sensors secured to the flexible sheet, and a mechanism operable to impact the flexible sheet or proximate to the flexible sheet to generate stress waves within and along a surface of the structure. The system further provides a data acquisition system capable of communicating with the sensors such that the data acquisition system generates feedback indicative of at least a portion of the structure based on data from the stress waves acquired by the sensors.

1) Field of the Invention
The present invention relates to non-destructive inspection and, more particularly, to non-destructive inspection of a structure for defects using an impact echo method.
2) Description of Related Art
Non-destructive inspection (NDI) of structures involves thoroughly examining a structure without harming the structure or requiring its significant disassembly. Non-destructive inspection is typically preferred to avoid the schedule, labor, and costs associated with removal of a part for inspection, as well as avoidance of the potential for damaging the structure. Non-destructive inspection is advantageous for many applications in which a thorough inspection of the exterior and/or interior of a structure is required. For example, non-destructive inspection is commonly used in the aircraft industry to inspect aircraft structures for any type of internal or external damage to or defects (flaws) in the structure. Inspection may be performed during manufacturing or after the completed structure has been put into service, including field testing, to validate the integrity and fitness of the structure. In the field, access to interior surfaces of the structure is often restricted, requiring disassembly of the structure, introducing additional time and labor.
Among the structures that are routinely non-destructively tested are composite structures, such as composite sandwich structures and other adhesive bonded panels and assemblies and structures with contoured surfaces. These composite structures, and a shift toward lightweight composite and bonded materials such as using graphite materials, dictate that devices and processes are available to ensure structural integrity, production quality, and life-cycle support for safe and reliable use. As such, it is frequently desirable to inspect structures to identify any defects, such as cracks, discontinuities, voids, or porosity, which could adversely affect the performance of the structure. For example, typical defects in composite sandwich structures, generally made of one or more layers of lightweight honeycomb or foam core material with composite or metal skins bonded to each side of the core, include disbonds which occur at the interfaces between the core and the skin or between the core and a buried septum.
Various types of sensors may be used to perform non-destructive inspection. One or more sensors may move over the portion of the structure to be examined, and receive data regarding the structure. For example, a pulse-echo (PE), through transmission (TT), or shear wave sensor may be used to obtain ultrasonic data, such as for thickness gauging, detection of laminar defects and porosity, and/or crack detection in the structure. Resonance, pulse-echo, or mechanical impedance sensors are typically used to provide indications of voids or porosity, such as in adhesive bondlines of the structure. High resolution inspection of aircraft structure is commonly performed using ultrasonic testing (UT) to provide a plan view image of the part or structure under inspection. Data acquired by sensors is typically processed and then presented to a user via a display as a graph of amplitude of the received signal. To increase the rate at which the inspection of a structure is conducted, a scanning system may include arrays of inspection sensors, i.e., arrays of transmitters and/or detectors.
Non-destructive inspection may be performed manually by technicians who typically move an appropriate sensor over the structure. Manual scanning requires a trained technician to move the sensor over all portions of the structure needing inspection. Manual scanning typically involves the technician repeatedly moving a sensor side-to-side in one direction while simultaneously indexing the sensor in another direction. In addition, because sensors typically do not associate location information with the acquired data, the same technician who is manually scanning the structure must also watch the sensor display while scanning the structure to determine where the defects, if any, are located in the structure. The quality of the inspection, therefore, depends in large part upon the technician's performance, not only regarding the motion of the sensor, but also the attentiveness of the technician in interpreting the displayed data. Thus, manual scanning of structures is time-consuming, labor-intensive, and prone to human error.
Semi-automated inspection systems have also been developed. For example, the Mobile Automated Scanner (MAUS®) system is a mobile scanning system that generally employs a fixed frame and one or more automated scanning heads typically adapted for ultrasonic inspection. A MAUS system may be used with pulse-echo, shear-wave, and through-transmission sensors. The fixed frame may be attached to a surface of a structure to be inspected by vacuum suction cups, magnets, or like affixation methods. Smaller MAUS systems may be portable units manually moved over the surface of a structure by a technician.
Automated inspection systems have also been developed. For example, the Automated Ultrasonic Scanning System (AUSS®) system is a complex mechanical scanning system that may employ through-transmission ultrasonic inspection. An AUSS system can also perform pulse-echo inspections, and simultaneous dual frequency inspections. The AUSS system has robotically controlled probe arms that may be positioned, for example, for TTU inspection proximate the opposed surfaces of the structure undergoing inspection with one probe arm moving an ultrasonic transmitter along one surface of the structure, and the other probe arm correspondingly moving an ultrasonic receiver along the opposed surface of the structure. To maintain the ultrasonic transmitter and receiver in proper alignment and spacing with one another and with the structure undergoing inspection, a conventional automated inspection system may have a complex positioning system that provides motion control in numerous axes, such as the AUSS-X system which has motion control in ten axes. Automated inspection systems and like robotics, however, can be prohibitively expensive. Further, orienting and spacing sensors with respect to the structure, and with respect to one another for TTU inspection, may be especially difficult in conjunction with structures with non-planar shapes, such as the inspection of curved structures and hat stringers. Also, conventional automated scanning systems, such as the AUSS-X system, may require access to both sides of a structure which, at least in some circumstances, will be problematic, if not impossible, particularly for very large or small structures. Furthermore, scanning systems inspect limited areas up to a few meters square.
Other inspection techniques have been utilized to inspect non-composite and non-metallic structures. For example, a technique used to inspect concrete and masonry materials is the impact-echo method. The impact-echo method was developed in the 1980's where a small sphere was used to generate short duration mechanical impact. It was discovered that by varying the diameter of the sphere and the impact force of the sphere, stress waves could be generated through concrete structural elements to discover internal flaws and defects. The time-of-flight diffraction technique includes impacting the concrete to generate longitudinal (P), shear (S), and surface (R) waves. The location of a defect may be determined by monitoring the speed of the stress waves. In particular the P and S waves are reflected by internal defects or external boundaries. When the reflected waves, or echoes, return to the surface, they produce displacements that are measured by a receiving transducer. The impact-echo technique typically requires an impactor to generate stress waves, a receiving transducer unit, an A/D-converter, and a computer installed with waveform analysis software to process the collected signals. A further discussion of the impact-echo method is disclosed in "The Impact-Echo Method," by Mary J. Sansalone and William B. Street, NDTnet, The Online Journal of Nondestructive Testing & Ultrasonics, Vol. 3, No. 2 (February 1998), which is incorporated herein by reference.
Despite utilizing impact-echo techniques to conduct non-destructive inspection of concrete and masonry structures, improvements are desired to inspect for various defects within a structure. In particular, an inspection system that is versatile and capable of being used for non-destructive inspection beyond concrete and masonry structures, such as for composites and metallic structures, is desired. Because composites and metallic structures used, for example, in the airline industry are typically much thinner than concrete and masonry structures tested by the impact-echo method, the stress waves mainly travel along the surface of the structure. Therefore, the collection and analysis of the stress waves through the metallic or composite structure is unlike those of stress waves traveling through concrete or masonry structures.
It would therefore be advantageous to provide a non-destructive inspection system that is capable of employing the impact-echo method for materials other than concrete or masonry. In addition, it would be advantageous to provide an inspection system that is portable and capable of inspecting structures effectively and efficiently. Furthermore, it would be advantageous to provide a non-destructive inspection system that is economical to manufacture and use.

Non-destructive inspection system and associated method


An optical system (1) of telescope includes an objective lens (10) for collecting incident light and transmitting the incident light along a light path, and an imaging lens group (20) disposed on the light path that makes the optical system focus on an image plane (40). The imaging lens group includes two positive lenses and two negative lenses. Each lens of the imaging lens group has a refractive index less than 1.80.

1. Field of the Invention
The present invention generally relates to an optical system of telescope, and more particularly to an optical system having high field brightness.
2. Description of the Prior Art
FIG. 1 of the attached drawings shows a conventional optical system 9 of telescope. The conventional optical system 9 comprises an objective lens 90 that collects incident light and transmits the incident light along a light path, a prism 91 disposed on the light path for refracting and converging the light beam in order to reduce the whole optical length of the optical system 9, an imaging lens group 92 disposed on the light path for adjusting the focus and determining an image plane 94 of the optical system 9, and two pieces of flat glass 93 disposed in front of the image plane 94. The imaging lens group 92 comprises four lenses, which are respectively first, second, third, and fourth lenses 95-98. The first lens 95 is a positive lens, the second lens 96 is a negative lens, the third lens 97 is a positive lens, and the fourth lens 98 is a positive lens. However, the conventional optical system 9 has a problem on field brightness, which can be clearly observed from the test chart shown in FIG. 2. The brightness at a circumferential edge is much lower than that at the center area. The plot shown in FIG. 2 indicates that the relative brightness is only 36% at the radius of 3 mm. The edge brightness is very low, which makes the edge of the field of view obscure or even dark.
Additionally, the first through fourth lenses 95-98 are all made of glass whose refractive indices are all higher than 1.80, as shown in the following table:
Refractive IndexAbbe coefficientLensType of Glass(Nd)(Vd)First lens 95S-LAH531.806140.90Second lens 96S-NPH11.808122.80Third lens 97S-LAH651.804046.60Fourth lens 98S-LAH651.804046.60
For a glass lens, generally, the higher the refractive index is, the lower the rigidity is. Therefore, the lenses 95-98 having high refractive indexes are difficult to process. Furthermore, the cost of the conventional optical system 9 is high for using such glass lenses having high refractive indexes.
Hence, an improved optical system is desired to overcome the above-mentioned disadvantages of the prior art.


An audio signal processing apparatus and method are provided. The apparatus includes a stability determiner and a sigma-delta modulator. The stability determiner divides a frequency band of an input audio signal into one or more sub-frequency bands, compares a level of the input audio signal for each of the sub-frequency bands with a threshold for the sub-frequency band, and generates a stability determination signal according to a result of the comparison. The sigma-delta modulator sigma-delta modulates the input audio signal according to the stability determination signal, and outputs a modulation signal.

1. Field
Apparatuses and methods consistent with the present disclosure relate to audio signal processing and, more particularly, to audio signal processing of sigma-delta modulation of an input audio signal.
2. Description of the Related Art
Class A, B, C, and Class D amplifiers are used to receive audio signals and output audibly perceptible signals. A Class D amplifier reduces deterioration in amplification efficiency that occur in class A, B, and C amplifiers. The Class D amplifier exhibits higher amplification efficiency than class A, B, and C amplifiers. Thus the Class D amplifier is widely used.
A Class D amplifier is a digital amplifier that modulates analogously input audio signals to produce digital audio signals, and amplifies and output digitally modulated audio signals.
Digital amplifiers have no data conversion loss and achieve amplification efficiency of 100% theoretically and thus are widely used.
Digital amplifiers modulate input audio signals to produce pulse signals and amplify the pulse signals. Sigma-delta modulation may be used to modulate audio signals to produce pulse signals. A modulator using sigma-delta modulation is referred to as a sigma-delta modulator.
A high order sigma-delta modulator may be used to enhance noise shaping.
However, a high order sigma-delta modulator accumulates signal values, which causes a large amount of oscillation to occur as the order of the sigma-delta modulator increases. The occurrence of oscillation may hinder the ability of the sigma-delta modulators to perform modulation operations, and thus an operation stability of sigma-delta modulator may not be secured.

Audio signal processing method and audio signal processing apparatus therefor