Techniques for playing and distributing MIDI tracks in the context of a non-real-time network such as the Internet. One of the techniques makes it possible to begin playing a multi-track MIDI file that is being received over the Internet before the entire file has been received. Others of the techniques permit playing of MIDI tracks that are generated in real time and then distributed via the Internet. The techniques ensure that expected network delays will not cause underflow in the MIDI buffer, provide a way of playing an "endless" MIDI stream received via the Internet, and provide ways by which players may collaborate and even participate in jam sessions over the Internet. Also disclosed are techniques for including decrypters in MIDI synthesizers and using the decrypters in the context of encrypted MIDI streams received via the Internet.

1. Field of the Invention
The invention relates generally to encryption and decryption of information and more particularly to the encryption and decryption of MIDI files and tracks distributed via a public network such as the Internet.
2. Description of the Prior Art
The following Description of the Prior Art provides an overview of the MIDI protocol, of techniques used to distribute music represented by means of the MIDI protocol, and of prior-art techniques for preventing copying of MIDI files.
The MIDI Protocol
The Musical Instrument Digital Interface (MIDI) is a standard protocol which was originally developed to permit electronic instruments such as synthesizers to communicate with each other. One common use of the protocol is permitting a musician to play more than one electronic instrument at once. The instrument that the musician is actually playing not only generates sounds, but also generates a sequence of event messages. An event message may for example be a note on message, that indicates that a note of a given pitch has started to sound or a note off message that indicates that the note has ceased sounding. Many other kinds of event messages are defined as well. Another instrument receives the event messages from the first instrument and responds by performing the actions indicated in the messages. Thus, if the message is a note on message, the other instrument will begin sounding the note, and will thus "play along with" the first instrument. For purposes of the present discussion, the event messages can be divided into two classes: the note on and note off messages and the remaining messages, which will be termed herein control messages.
The sequence of MIDI protocols to which a musical instrument directly responds is termed herein a MIDI stream. Devices which respond to a MIDI stream are termed herein MIDI devices. MIDI devices include electronic musical instruments and the sound boards of many computers. In a MIDI stream, time relationships between events are simply determined by when the events appear in the event stream. For example, if a note is to be held for a period of one second, the note on message for the note will appear in the MIDI stream one second before the note off message for the note appears in the stream. Since the MIDI device will start sounding the note in response to the note on message and stop sounding the note in response to the note off message, the note will be sounded for one second. It should be further noted at this point that the MIDI device may be assigned one or more channels. Each channel is represented by a channel number and each event message includes a channel number. A given MIDI device will respond to a given event message only if the channel number in the event message specifies one of the channels assigned to the MIDI device.
Each MIDI device has three connectors for the cables used to carry MIDI streams. One of the connectors is an output connector. The cable connected to it carries a MIDI stream of event messages that originate at the MIDI device; another of the connectors is an input connector; the connected cable carries a MIDI stream of event messages that the MIDI device will respond to if the event messages specify the channel currently assigned to the MIDI device. The third connector is a through connector; the connected cable carries the MIDI stream received in the input connector.
The connectors and associated cables can be used to configure groups of MIDI devices. FIG. 5 shows one such configuration 501. Each MIDI device 113 has the three connectors: Input 505, output 507, and through 509. Output 507(a) of MIDI device 113(a) is connected by MIDI cable 510 to input 505(b) of MIDI device 113(b), while through connector 509(b) is connected to input 505(c) of MIDI device 113(c). As a consequence of these connections, the output of MIDI device 113(a) is played on both MIDI devices 113(b) and 113(c); additionally, notes produced by players of devices 113(b) and (c) will be heard from those devices.
In the MIDI stream, the interval of time between two event messages is simply the amount of time between when the first event message appears in the stream and when the second event message appears in the stream. For this reason, a MIDI stream cannot be stored in a medium such as a file which does not preserve the intervals between event messages and also cannot be transmitted by such a medium. The problem of storing a MIDI stream was solved by a special MIDI device 113, MIDI sequencer 511. Sequencer 511 receives one or more MIDI streams 111 and makes MIDI tracks 105 out of the MIDI streams 111 and MIDI files 103 out of the MIDI tracks. The files and tracks are stored in storage devices such as standard memories and/or disk drives.
As shown in FIG. 1 of the present application, MIDI file 103 has a header 104 which contains information such as the number of tracks. The MIDI file also contains at least one track 105. A given track i in such a file is indicated hereinafter by 105(i). Each track 105(i) contains a sequence of events 106. Each event 106(j) has two parts: an event message 117 and an elapsed time descriptor 119. The elapsed time descriptor indicates the time that is to elapse between the preceding event 106(j-1) and event 106(j). As can be seen from the foregoing, a given event 106's position in file 103 may be indicated by the index of its track and its own index in the track. Event 106(i,j) is thus event j in track i.
The MIDI stream 111 is generated from MIDI file 103 by MIDI controller 107. Prior-art MIDI controller 107 does this by first writing all of the tracks 105 from file 103 into controller memory 109, as shown by arrow 108, and then reading all of the tracks simultaneously in the fashion just described, as shown by arrow 110. To accomplish the simultaneous reading, MIDI controller 107 maintains a song position time value 121 which the controller can use together with the elapsed time descriptors to determine which event messages are to be output from the tracks at a given time. As would be expected from this procedure, and as shown in FIG. 1, MIDI stream 111 generally consists of interleaved event messages 117 from the tracks 105. MIDI stream 111 may then be responded to by any MIDI device 113, which then drives loudspeaker 115 to produce the sounds specified by MIDI stream 111. The standards for both MIDI streams and MIDI files are defined in the MIDI Specification, copyright 1983 and available from the MIDI Manufacturers' Association.
An important property of both MIDI tracks and MIDI streams is that they represent commands to MIDI devices, and not the output of those devices, and are consequently much smaller than representations of the output of the devices. This property is particularly valuable where storage space is limited, for instance in low-cost electronic devices, or where a low-bandwidth medium such as the Internet is being used to transmit the representation.
Distributing MIDI Files on the Internet
The advent of the personal computer opened whole new realms of applications for MIDI. First, many computers had sound boards that could interpret MIDI streams and were therefore themselves MIDI devices. Second, MIDI's small size and ability to represent actions that happen in real time made it attractive for any such application. For example, makers of game software used MIDI to provide program-controlled sensory feedback to a joystick. Finally, there was the wild growth of the Internet. The Internet's bandwidth problems made MIDI particularly attractive as a way of distributing music for MIDI devices over the Internet. FIG. 1 shows a prior-art technique for distributing music over the Internet An important limitation of the Internet is that it is not a real-time medium. This problem was overcome in the prior art by distributing music for MIDI devices over the Internet as MIDI files 105 using the techniques shown in FIG. 1. First, a MIDI file 103 was made from the MIDI stream 111, then the MIDI file was distributed over the Internet, and the arrangement shown at 101 of FIG. 1 was used to play the file on a MIDI device 113. The parent and the grandparent of the present patent application both concerned improved techniques for overcoming the non-real-time characteristics of the Internet and thereby making it possible to begin hearing a MIDI file without delay and to hear MIDI music as it was produced.
Protecting MIDI Tracks and Files: FIG. 12
The present patent application deals with the problem of protecting MIDI tracks and files from unauthorized copying. Copying is generally a more severe problem in the digital realm than in the analog realm because a copy of a digital representation is as good for all purposes as the original digital representation. In the case of MIDI tracks and files, copying is made even more attractive by the smallness of the MIDI representation and by the fact that it can be played on any kind of MIDI device.
In the prior art, MIDI files and tracks have been protected against copying by using the encryption and decryption techniques generally available for data. FIG. 12 shows a system 1201 in which such techniques are applied to a MIDI file 103 which is being sent by a network 1211 from a source 1203 to a destination 1213. MIDI file 103 is provided to encrypter 1207, which uses one of many known techniques to produce an encrypted version of MIDI file 1209 which has been encrypted using an encryption key 1208. Once encrypted, the file may only be decrypted by someone who has a decryption key for the file.
Encrypted file 1209 is then sent via network 1211 to destination 1209, where it is decrypted by decrypter 1217 using the decryption key 1218 appropriate to the encryption made by encrypter 1207. Decrypted MIDI file 1219 is identical to original MIDI file 103 and can be read by a file to stream translator 1221 to produce a MIDI stream 111 in the fashion described above. MIDI stream 111 is then sent to MIDI device 113, which produces analog signals 1227 that then go to loud speaker 115. For an overview of the large variety of encryption techniques which may be employed in system 1201, see Bruce Schneier, Applied Cryptography, Protocols, Algorithms, and Source Code in C, John Wiley and Sons, New York, 1994.
From the point of view of preventing copying of MIDI tracks and files, the arrangement of FIG. 12 has a number of problems. What the publisher of the MIDI track or file wishes the user to get in unencrypted form is only the sound produced when the MIDI device plays the MIDI stream. Even giving the user access to MIDI stream 111 is unacceptable, since anyone who has a MIDI sequencer 511 can produce a MIDI file 103 from the MIDI stream 111, and MIDI sequencers 511 can easily be implemented in software that will run on a standard personal computer (PC).
In system 1201, the user has access to decrypted MIDI at many points. Most obviously, system 1201 produces decrypted MIDI file 1219, which is accessible to the user of system 1201 and is equivalent for all purposes to original MIDI file 103. The user further has access to events 1220 as they are read from decrypted MIDI file 1219 to file to stream translator 1221, and can simply read the events into his own MIDI file. Finally, the user has access to MIDI stream 111, and can output stream 111 to a sequencer 511 to make his or her own MIDI file 103. One feature of modern computer systems which makes access to events 1220 and MIDI stream 111 particularly easy is that file to stream translator 1221 and MIDI device 113 are often implemented as dynamically-linked software libraries (DLLs). When a program executing in a personal computer uses programs in a dynamically-linked library, the DLL is linked to the program that uses it as the latter program begins executing. It is consequently easy for the user to substitute his own DLL for either the file to stream translator or the MIDI device 113 for the ones intended to be used to play the MIDI file, and instead of playing the MIDI file, the user can simply output the events 1220 to a file of his own or output MIDI stream 111 to a sequencer 511.
There are a number of requirements beyond security which must be satisfied by a commercially-viable encryption system for MIDI tracks and streams. First, a single source will be typically transmitting a file or track to many destinations. Second, many granularities of encryption must be possible. On the side of the publisher, it must be possible to encrypt entities ranging in size from the equivalent of a multi-CD album through a live concert down to an individual song; on the side of the recipient, it must be possible to implement decryption on a per-site, per-machine, per-code copy, or per-instance of execution basis. Finally, any encryption scheme must be cheap, but it also must be effective enough. In the context of MIDI publishing, effective enough means that it need not provide absolute security, or even security against a professional hacker, but simply be secure against the ordinary user.
It is an object of the present invention to overcome the problems of prior-art encryption for MIDI files and provide commercially-viable techniques for encrypting and decrypting MIDI tracks and files.

Methods and apparatus for encrypting and decrypting MIDI files


In a communications system implementing Transmission Control Protocol/Internet Protocol (TCP/IP), an apparatus and method for increasing the number of NAKs transmitted by a receiving device when an RLP error is detected in cases where the link speed into the RLP receiver is high, when the TCP window of the sender approaches the maximum or when the percentage of NAKs for which retransmissions cannot be fulfilled approaches a threshold. In a second aspect of the invention, the apparatus and method increases the number of retransmissions transmitted by a sending device when an RLP NAK is received in cases where the link speed out of the RLP sender is high and the transmission round is the first, when the TCP window of the sender approaches the maximum or when the percentage of NAKs for which retransmissions cannot be fulfilled approaches a threshold.

Transmission Control Protocol/Internet Protocol (TCP/IP) is the basic communication language or protocol of the Internet. It can also be used as a communications protocol in a private network (either an intranet or an extranet). When one is set up with direct access to the Internet, his or her computer is provided with a copy of the TCP/IP program just as many of the other computers that he or she may send messages to or get information from also has a copy of TCP/IP.
TCP/IP is a two-layer protocol. The higher layer, TCP, manages the assembling of a message or file into smaller packets that are transmitted over the Internet and received by a TCP layer that reassembles the packets into the original message. The lower layer, IP, handles the address part of each packet so that it is routed to the correct destination. Each gateway computer on the network checks this address to determine where to forward the message. Even though some packets from the same message are routed differently than others, they are reassembled at the destination.
In TCP/IP, there is a limit on the number of bytes that can be transmitted before confirmation, usually in the form of an Acknowledgment (ACK), is received. This limit is typically referred to as a current send window (snd_wnd) and is constantly updated during the lifetime of a TCP session. The current snd_wnd is calculated as the minimum of the sender congestion window (cwnd) and the receiver advertised window (rcvwnd). The sender cwnd is an attempt by the sender to estimate from past experience the amount of data it can send without causing network congestion. At the beginning of a TCP session, the sender cwnd starts low and gradually increases as the sender learns how much bandwidth is available. The rcvwnd depends on the memory and processing capabilities of the receiver and is typically 64 Kbytes (the maximum allowed by TCP). However, the rcvwnd could be significantly smaller. The rcvwnd value is typically fixed during the connection and it places an upper limit on the maximum send window (max_snd_wnd) when there is no congestion or packet loss that would limit the sender cwnd. The current snd_wnd value increases until it reaches the max_snd_wnd value, which is typically equal to the rcvwnd. For example, the rcvwnd in a personal computer (PC) running Windows is 64 Kbytes. However, in some TCP/IP implementations such as Sun Solaris 2.6/2.7, the rcvwnd could be 8 Kbytes. In the case of 64 Kbytes, TCP/IP cannot send a single Kbyte past the 64th Kbyte if none of the previous 64 Kbytes sent have been acknowledged by the TCP/IP instance with which it is communicating. (Some examples of TCP/IP instances are web page server, email server, and PC.) In other words, once the 64 Kbyte limit is reached, the TCP/IP becomes a stop-and-wait protocol with significantly decreased throughput.
Referring to FIG. 1, a Server or other Host 102 transmits 64 Kbyte frames consisting of, for example, 1.5 Kbyte packets to a Mobile Station (MS) 104. As shown, delay is introduced during the transport of the packets from the Server 102 to the MS 104. In the system, the transmission speed (link speed) is low and the delay is high. The MS 104 receives the first 1.5 Kbyte packet in the first frame and sends a TCP/IP ACK back to the Server 102 while other packets in the same frame are still being transmitted. Because the Server 102 receives the ACK before the entire 64 Kbytes are sent, TCP/IP in the Server 102 does not have to stop transmitting packets and throughput is not decreased. (See bolded lines in FIG. 1.)
FIG. 2 illustrates the transmission of 1.5 Kbyte packets in 64 Kbyte frames in a system where the transmission speed is high and the transport delay is low. In such a case, as in FIG. 1, the MS 104 receives the first 1.5 Kbyte packet and sends a TCP/IP ACK back to the Server 102 while other packets in the same 64 Kbyte frame are still being transmitted. Again, because the Server 102 receives the ACK before the entire 64 Kbytes are sent, TCP/IP in the Server 102 does not have to stop transmitting packets and throughput is not decreased. (See bolded lines in FIG. 2.)
FIG. 3 illustrates the transmission of 1.5 Kbyte packets in 64 Kbyte frames in a system where the transmission speed is high and the transport delay is high. In this case, the Server 102 sends the entire first 64 Kbyte frame to the MS 104 without receiving a TCP/IP ACK for any of the 1.5 Kbyte packets in the first frame. In this situation, the TCP/IP in the Server 102 cannot begin sending any of the packets in the second set of 64 Kbytes in the download. Instead, the TCP/IP becomes a stop-and-wait protocol with significantly decreased throughput.
Next generation CDMA systems, such as CDMA 2000, achieve link speeds higher than current CDMA systems and the maximum delay that can be tolerated is decreased. At 300 Kbps, with a 64 Kbyte max TCP window, the maximum delay that can be tolerated is 2.7 seconds. If current RLP methods are used in next generation CDMA systems, delay is likely to exceed 2.7 seconds in many calls because at higher data rates, the TCP window is exhausted in a shorter time. In CDMA 2000, data calls use RLP to correct errors on the radio link. RLP attempts to correct radio errors in accordance with the method specified in Section 10 of TIA/EIA/IS-707-A-2 (IS-707-A-2). A copy of IS-707-A-2 may be obtained via a world wide web site located at www.tiaonline.org, or by writing to Telecommunications Industry Association, 1300 Pennsylvania Ave., Suite 350, Washington, D.C. 20004 USA. In accordance with IS-707-A-2, RLP attempts to correct radio errors as follows: Consider a new frame before it is transmitted across the radio link for the first time. If the frame is "erased" by the radio link, for Y rounds, the RLP receiver instance (RLP in the receiving device) sends S(Y) number of NAKs to the sender requesting S(Y) copies of the frame. That is, in the first round, the RLP sends S(1) NAKs to the source requesting transmission of S(1) copies of the frame. If none of the copies (retransmissions) arrive, in the second round, RLP sends S(2) NAKs to the source requesting S(2) more copies of the frame. The number of NAKs S(1) and S(2) are negotiated by the RLP at the beginning of the RLP session. This process continues for Y rounds. If all rounds are unsuccessful, RLP aborts (gives up) and the frame that the packet was a part of is corrupted and must be retransmitted by TCP/IP. If two or more TCP/IP packets in a row contain at least one RLP segment or frame, each of which was unsuccessfully retransmitted and led to an abort, TCP/IP is very likely to time out. When TCP/IP times out it typically takes approximately two to three seconds for the corrupted packets to be resent. This is a significant delay, and thus the number of aborts should be minimized.
As the Frame Error Rate (FER) increases, the probability of an RLP abort increases. The amount of overhead caused by RLP retransmissions is represented roughly by the equation F*S(1), where F is the FER seen by the frames and, as set forth above, S(Y) represents the number of NAKs sent for round number Y. In other words, F*S(1) is a good approximation for the average number of retransmissions that must be sent for each new RLP frame that is sent. Thus, the throughput of RLP is roughly 1/(1+F*S(1)), because for every one new frame sent (the numerator), the total number of frames that must be sent is 1+F*S(1) (the denominator). For example, if S(Y) increases from 1 to 3 and F=10%, the RLP throughput decreases from 91% to 77% (1/(1+(0.10*1)=0.91 to 1/(1+(0.30*1)=0.77). However, if S(1)=3 rather than S(1)=1, the average RLP ordered delay decreases significantly because an RLP frame whose original transmissions is erased, is much more likely to be successfully retransmitted in its first round of retransmissions. (If one sends three retransmissions, it is much more likely that at least one will succeed than if only one is sent.) It follows that a frame delivered in the first round of retransmissions experiences less delay than a frame delivered in the second round of retransmissions.
A paper written by John Harris & Manish Airy describes a method that shows that the average ordered delay decrease in the case described above is roughly 33% (from roughly 220 ms to roughly 145 ms). The paper is entitled Analytical Model for Radio Link Protocol for IS-95 CDMA Systems and is published in IEEE Vehicular Technology Conference Proceedings in Spring 2000 (VTC 2000-Spring Tokyo. 2000 IEEE 51st, Volume: 3, 2000 Page's 2434-2438 vol.3). It can be seen from this case that by negotiating more NAKs per round in RLP, one can reduce the RLP delay and decrease the occurrence of TCP/IP becoming a stop-and-wait protocol. However, as described earlier, increasing the number of NAKs per round can cause a decrease in RLP throughput. As shown in FIG. 1, when transmission speed is low, there is no TCP/IP stop-and-wait problem and thus no need to unnecessarily decrease RLP throughput.
Aborts also contribute to decreased RLP throughput in an RLP sender instance (RLP in a sender device). When a data frame is transmitted from a sender device to a receiver device, a copy of the frame is stored in the sender's retransmission buffer. If the frame is not received at the receiver device, the RLP receiver instance sends a NAK X (where X identifies the erased frame's sequence number) to the sender. The RLP sender receives the NAK X requesting retransmission of frame X and attempts to retrieve the copy of frame X from the retransmission buffer. The retransmission buffer has a finite fixed size. For example, consider a case where the retransmission buffer holds exactly D number of RLP frames, where D=256. When the 257th RLP frame is sent, the sender's RLP retransmission buffer is full, and the first (oldest) RLP frame is deleted from the retransmission buffer to make room for the 257th RLP frame. If the RLP sender instance receives a NAK for retransmission of an RLP frame that has been deleted from the RLP retransmission buffer, the RLP sender instance is not capable of satisfying the NAK by retransmitting the RLP frame. When this happens, an RLP miss occurs. For example, an RLP miss generally occurs when a NAK for retransmission of a frame X is received after frame Y, and (Y−X) is greater than D. An RLP frame that experiences a miss, is aborted by RLP (i.e., RLP gives up on the frame and leaves the error to be potentially retransmitted by an application or higher level transport protocol). This causes extra delay and poorer quality of service for the end user. Reducing the RLP delay, as described earlier, reduces the probability of an RLP miss. This is because, an RLP miss tends to occur when a frame must be retransmitted a long time after its original transmissions, e.g. after many rounds of retransmission attempts. If retransmissions succeed in the earlier rounds, the problem of an RLP miss is reduced. One can decrease the RLP delay as described earlier, but this adds cost due the decrease in throughput. Thus, if the RLP miss problem is occurring, the delay should occur.
An RLP miss can be detected at both the sender and receiver. At the RLP sender, an RLP miss can be detected when the RLP receiver receives a NAK that it cannot satisfy because it has deleted it as described earlier. At the RLP receiver, it is more difficult to detect that an RLP miss has occurred. However, for example, if the RLP negotiates a 1,1,1,1,1 scheme, one can track the percent of RLP NAKs that are successful (result in a retransmission) in each round. For example, if 95% of the NAKs in the first 4 rounds are successful, but 0% of the NAKs in the 5th round are successful, the NAK miss problem is occurring in the 5th round. Additionally, if a sufficiently small percentage of the NAKs are last round NAKs, the NAK miss problem is not significant. Further, the RLP receiver can probe for the existence of the NAK miss problem by preemptively sending NAKs for frames that it does not need retransmissions for in order to probe the sender's retransmission buffer depth.
Thus, there is a need for an apparatus and method for dynamically adjusting the number of NAKs sent by an RLP receiver instance when an RLP error is detected in cases where the link speed into the RLP receiver is high, when the TCP window of the sender approaches the maximum, or when the percentage of NAKs for which retransmissions cannot be fulfilled approaches a threshold. There is also a need for an apparatus and method for dynamically adjusting the number of retransmissions sent by an RLP sender instance when a NAK is received in cases where the link speed out of the RLP sender is high, when the TCP window of the sender approaches the maximum or when the percentage of NAKs for which retransmissions cannot be fulfilled approaches a threshold.

Method for dynamically adjusting the number of retransmissions and NAKs in a communications system implementing TCP/IP


A two-pole generator rotor assembly including a one-piece shaft, a prewound field coil assembly and a one-piece shaft. The one piece shaft includes a pair of axially spaced shaft end portions and a substantially cylindrical portion integrally formed with the spaced shaft end portions and interposed therebetween. The substantially cylindrical central portion includes a through slot for accommodating the prewound field coil assembly, with the through slot including a pair of opposed wall portions adapted to engage an outer peripheral portion of the prewound field coil assembly and provide means for retention of the prewound field coil.

Generators as utilized in IDGs, APU GENs, and other similar type electrical generators for aircraft are termed "electromechanical" devices because they convert mechanical energy from the appropriate power source to electrical energy. This energy is then utilized throughout the aircraft to light lights, cook food, and power complex systems such as pilot instrumentation, radar, communications, flight computers, etc. The conversion is accomplished as the rotational mechanical energy of the engine, for example, transmits a torque to the generator rotor, through appropriate gearing, causing this rotor to spin.
This two-pole rotor has wires wound around a field pole piece making up what is termed the field coil assembly. When an electric current is passed through this rotating field coil assembly, or more specifically through the wires wound on the field pole piece, a rotating magnetic field results. This rotating magnetic field or flux, in turn, induces a field in the structure of the generator surrounding the rotor assembly known as the stator which also has wires wound around its assembly. Connections to the windings of this stator are then made to allow the electric power to be delivered to the various loads of the aircraft.
Generally, the two-pole rotor utilized in this type of generator is composed of a plurality of precision fitted parts which are bolted or welded together. While this technical approach is functionally satisfactory, a disadvantage resides in the fact that the total costs involved in producing this rotor as a result of the required precision fitting of the components as well as the necessary welding, pinning and bolting operations, is relatively high. Further, if this precision fitted unit is to be repaired, a lengthy and expensive process requiring first that the welds be cut prior to any actual repair activity beginning must be undertaken.
Conventionally, wedge portions are provided as part of the rotor assembly. These wedges are generally hollowed out or configured to the coil profile which is somewhat rounded to accommodate the large number of windings in the field coil assembly required to generate the necessary magnetic field described above. To allow for the transmission of the large torques generated by the aircraft engine in this connection, high strength axial retention bolts are utilized to bolt the shaft ends to the field pole piece. High strength radial retention bolts are utilized in turn to retain the separate field core accommodating wedges to the field pole pieces under the tremendous centrifical forces generated by the speed at which this rotor assembly spins, typically in excess of 20,000 RPM.
To aid the torque transmission capability required to allow this assembly to spin at such a high speed, an oil accommodating canister surrounding the field coil is typically welded to the ends of the shaft after assembly and then finish ground to size. A disadvantage of this approach resides in the fact that the completed unit is, at best, difficult if not impossible to repair or service and, taking into account the manufacturing steps and processes, the unit is difficult and expensive to construct.
Specifically, with regard to service and repair, the welding of the oil accommodating canister to the ends of the shaft renders the conventional two-pole rotors more or less disposable. This is because the expensive and time consuming task of cutting these welds must first be accomplished to gain access to the core assembly which is encased by the oil accommodating canister before any service or repair may begin.
If this lengthy and expensive procedure is undertaken, and the unit is repaired, additional work is usually required to regrind the grooves, known as bearing races, which allow the unit to rotate on its bearings, as they are typically out of concentricity when the unit is reassembled.
Typical examples of rotor constructions of the aforementioned type are disclosed in, for example, U.S. Pat. Nos. 4,510,679, 4,513,641, 4,562,641, 4,591,749, 4,757,603, 4,674,178, 4,625,135, 4,598,218, and 4,614,888. While each of these patents provide various approaches for constructions of a rotor, each technical approach utilizes a multi-piece shaft construction and, consequently, suffers from the above-noted disadvantages.

One-piece rotor shaft for two-pole rotor


A honeycomb structure made of a silicon carbide-based porous body and having a number of through-holes extending in the axial direction, separated by partition walls. The strength and Young""s modulus of the silicon carbide-based porous body satisfy the following relation:

The present invention relates to a honeycomb structure used in a filter for purification of automobile exhaust gas, a catalyst carrier, or the like, as well as to a process for production of such a honeycomb structure.
Porous honeycomb structures are in wide use as a filter for capturing and removing the particulate substance present in a dust-containing fluid (e.g. exhaust gas emitted from diesel engine), or as a catalyst carrier for loading thereon a catalyst component capable of purifying the harmful substances present in an exhaust gas. It is known that as a material constituting such a honeycomb structure, there are used refractory particles such as silicon carbide (SiC) particles and the like.
As a specific technique related thereto, there is disclosed, in, for example, JP-A-6-182228, a porous, silicon carbide-based catalyst carrier of honeycomb structure, obtained by using, as a starting material, a silicon carbide powder having a given specific surface area and a given impurity content, molding the material into a desired shape, drying the molded material, and firing the resulting material at a temperature of 1,600 to 2,200xc2x0 C.
Meanwhile, there are disclosed, in JP-A-61-26550, a process for producing a vitrifying material-containing refractory product, which comprises adding a vitrifying material to an easily oxidizable material or a refractory composition containing an easily oxidizable material, mixing, kneading and molding them together with a binder, and open-firing the molded material in a furnace containing a non-oxidative atmosphere; and, in JP-A-8-165171, a silicon carbide molded material obtained by adding, to a silicon carbide powder, an organic binder and inorganic binders of clay mineral series, glass series and lithium silicate series and molding the resulting material.
Also, in JP-A-6-182228 is introduced a process for producing a conventional porous, silicon carbide-based sintered body, which comprises adding, to silicon carbide particles as an aggregate, a binder such as vitreous flux, clayey material or the like, molding them, and firing the molded material at a temperature at which the binder melts.
Further, as to a high-temperature use ceramic filter produced by molding refractory particles which consist of silica sand, a ground pottery, a metal oxide (e.g. Al2O3, TiO2, or ZrO2), silicon carbide, nitride, boride, other refractory material, or the like and which are adjusted to a given grain size, to a porous, bottomed cylindrical material using a refractory binder such as water glass, frit, glaze or the like, there are disclosed, in JP-B-61-13845 and JP-B-61-13846, the preferred average particle diameter and particle size distribution of refractory particles, the preferred porosity, average pore diameter, pore volume and partition wall thickness of cylindrical material, etc.
In the sintering (necking between particles) caused by the recrystallization of silicon carbide powder per se, shown in JP-A-6-182228, the silicon carbide component vaporizes from the surfaces of silicon carbide particles and the vaporized silicon carbide component condenses at the contact areas (necks) between silicon carbide particles; as a result, the necks grow and the particles are bonded to each other. There are problems, however, that this method brings a high cost since a very high firing temperature is required to be employed in order to vaporize silicon carbide, and that the yield after firing is reduced since a material of high thermal expansion coefficient is required to be fired at a high temperature as well.
The above process allows production of a porous body of high strength; however, the porous body has a high Young""s modulus which is derived from the physical properties possessed by the silicon carbide used as a raw material.
In general, coefficient (R) of thermal shock resistance is shown by the following formula (1). In the following formula, S is a fracture strength, xcexd is a Poisson ration, E is a Young""s modulus, and xcex1 is a thermal expansion coefficient. xcexd and xcex1 are characteristic values of each material and are almost constant in each material; meanwhile, S and E vary greatly depending upon the porosity, fine structure, etc. of each material.
R=S(1xe2x88x92xcexd)/Excex1xe2x80x83xe2x80x83(1)
As shown in the above formula, thermal shock resistance is directly proportional to strength but inversely proportional to Young""s modulus. Therefore, according to the process for producing a sintered body disclosed in JP-A-6-182228, a sintered body having a sufficient thermal shock resistance, while it has a high strength though, can not be produced since Young""s modulus becomes high.
Meanwhile, there is a problem that a localized heat generation is caused by the low thermal conductivity of the filter in the case of the technique of bonding a silicon carbide powder (as a raw material) with a vitreous material, shown in JP-A-61-26550 and JP-A-6-182228 wherein a low firing temperature of 1,000 to 1,400xc2x0 C. is employed; if one tries to burn the particulates collected by and deposited on the filter for reactivation of the filter, in the case that the sintered body produced by the technique is used, for example, as a diesel particulate filter (DPF) for removing the particulates contained in the exhaust gas emitted from a diesel engine.
Further, the filter shown in JP-B-61-13845 and JP-B-61-13846 is porous but is a bottomed cylindrical material having a large partition wall thickness of 5 to 20 mm; therefore, there is a problem that the filter is not usable under the high space velocity (SV) condition like a filter for purification of automobile exhaust gas.
The present invention has been made in view of the above-mentioned situation of the prior art, and is intended to provide a honeycomb structure which contains refractory particles such as silicon carbide particles and the like and yet can be produced at a relatively low firing temperature at a low cost, which has a high strength and a high thermal shock resistance, and which can be suitably used, for example, as a filter for purification of automobile exhaust gas by a treatment such as clogging of through-channel at its inlet or outlet, or as a catalyst carrier, even under a high SV condition; and a process for producing such a honeycomb structure.
According to the present invention there is provided a honeycomb structure made of a silicon carbide-based porous body and having a plural number of through-channels extending in the axial direction, separated by partition walls, characterized in that the strength and Young""s modulus of the silicon carbide-based porous body satisfy the following relation:
Strength (MPa)/Young""s modulus (GPa)xe2x89xa71.1.
In the present invention, the strength and Young""s modulus of the silicon carbide-based porous body preferably satisfy the following relation:
Strength (MPa)/Young""s modulus (GPa)xe2x89xa71.25.
Further in the present invention, the strength and Young""s modulus of the silicon carbide-based porous body preferably satisfy the following relation. In the present invention, the silicon carbide-based porous body preferably contains silicon carbide particles as aggregate and metallic silicon as a binder:
Strength (MPa)/Young""s modulus (GPa)xe2x89xa71.3.
According to the present invention, there is also provided a process for producing a honeycomb structure, which comprises adding metallic silicon and an organic binder to raw material silicon carbide particles, mixing and kneading them to obtain a readily formable puddle, molding the readily formable puddle into a honeycomb-shaped molded material, calcinating the molded material to remove the organic binder in the molded material, and firing the resulting material, characterized in that the addition amount of the metallic silicon is 15 to 40% by weight based on the total amount of the raw material silicon carbide particles and the metallic silicon.
In the present invention, the firing is preferably conducted in a temperature range of 1,400 to 1,600xc2x0 C.

Honeycomb structure and process for production thereof

Abstract: The honeycomb structure contains refractory particles such as silicon carbide particles and the like and yet can be produced at a relatively low firing temperature at a low cost, has a high strength and a high thermal shock resistance, and can be suitably used, for example, as a filter for purification of automobile exhaust gas by a treatment such as plugging of through-channel at its inlet or outlet, or as a catalyst carrier, even under a high SV condition.


In a linear displacement pump, liquid is discharged by driving a piston along at least part of a stroke length. While discharging the liquid, a linear position of the piston is sensed at a plurality of positions along the stroke length, and a plurality of output signals is produced. Based on one or more of the output signals, an operational state of the pump is determined.

A pneumatically-driven, high-pressure liquid pump may employ a large-diameter gas-driven piston directly linked to a smaller-diameter piston that acts to positively displace liquid. Such a pump is often equipped with an end-of-stroke sensor that determines when the pump should be reset for the next pumping cycle (i.e., at or near the end-of-stroke position of the pistons). This is particularly true in "one stroke per run" applications entailing low flow rates and pulsation-free delivery of liquid, one specific example being low-flow high performance liquid chromatography (HPLC). Typically, end-of-stroke sensing has been implemented by a piston coming into contact with a mechanical relay or optical interrupt as the piston reaches the end-of-stroke. The sensor may then transmit a signal to a pump controller to initiate a re-stroke. Apart from determining end-of-stroke, the sensor is not useful for acquiring any other type of information, and typically no other sensors are employed in the pump to monitor piston movement and operation. Moreover the pump, particularly in high-pressure applications, is prone to fluid leakage through seals, check valves, and fluid connections downstream from the pump. In one stroke per run applications, the duration of the run time of the pump during the discharge stroke may be long enough that fluid leakage constitutes a significant impairment to pump performance or to the application in which the pump is implemented. Also, in low flow rate applications the leakage rate may be large relative to the flow rate. Likewise, fluid leakage may be a significant detriment in applications requiring highly precise flow rates.
Therefore, there is a need for a pump capable of sensing or monitoring piston movement and operation. There is also need for a pump capable of providing information useful in determining leakage and other diagnostic information.

Linear displacement pump with position sensing and related systems and methods


An apparatus for controlling a vehicle includes a target rotational speed calculator, a transmission controller, a fuel supply stop controller, and an inhibition controller. The target rotational speed calculator is configured to calculate a target rotational speed of an internal combustion engine in accordance with a drive condition of the vehicle. The transmission controller is configured to change a transmission gear ratio of an automatic transmission so that a rotational speed of an output shaft of the internal combustion engine approaches the target rotational speed. The output shaft of the internal combustion engine is connected to the automatic transmission via a transfer mechanism. The fuel supply stop controller is configured to stop supplying fuel to the internal combustion engine if a predetermined fuel supply stop condition is satisfied during deceleration of the vehicle.

1. Field
The present disclosure relates to an apparatus for controlling a vehicle and a method for controlling a vehicle.
2. Description of the Related Art
Japanese Unexamined Patent Application Publication No. 2003-341387 describes an apparatus for controlling a vehicle including a drive mechanism that transfers the output of an internal combustion engine to a drive wheel via a start clutch and a continuously variable transmission. According to the control apparatus, if the engine speed (the rotational speed of the input shaft of the start clutch) is lower than the rotational speed of the output shaft of the start clutch by a predetermined value or greater for a predetermined period of time or longer, driving in a fuel cutoff mode is inhibited. Thus, an excessive drop of the engine speed can be prevented.

Apparatus for controlling vehicle and method for controlling vehicle


A roll-up or curtain type door or panel wall for use in large doorways, the door having an improved support apparatus, an improved spring mounting mechanism, and a unique bearing block which also functions to support the door as it is rolled up. The roll-up door has a substantially stronger hollow hexagonal barrel assembly which is less susceptible to flexural stress, and a spring mounting arrangement which allows the springs to shrink or grow longitudinally as the door is rolled up or down. The barrel assembly is mounted on pivoting support means allowing the barrel assembly to move away from and toward the guide tracks as the door is rolled up and down, whereby the variation in diameter of the barrel assembly does not affect the performance of the door. Interlocking bearing blocks are mounted on the outside side edges of the roll-up door to provide support as the door is rolled onto the barrel assembly and also to provide an edge seal to prevent air from flowing around the edges of the door when it is in its lowered position. A novel seam configuration for releasably joining adjacent panels of the roll-up door is disclosed as part of the invention.

Field of the Invention
The present invention relates generally to a panel construction for a roll-up or curtain type door or other panel assembly and, more particularly, to a construction which facilitates replacement of individual panels and provides a strengthened assembly. The panel is usable in a flexible roll-up door or a planar panel combination.

Panel construction for a wall or roll-up door system


Coumarin dyes such as alkylaminocoumarincarboxamides which have functional hydroxyl groups or which are chemically attached to vinyl monomers such as methacrylic acid. The dyes which are chemically attached to vinyl monomers can be copolymerized, e.g. with acrylic monomers to produce a coumarin dye-containing polymer. The dyes which have functional hydroxyl groups can be reacted with an existing polymer or copolymer, e.g. a copolymer of styrene and acrylic acid to esterify the acid groups of the polymer to form a coumarin dye-containing polymer. Such coumarin dye-containing polymers are formed into films and fibers which when poled in an electric field yield a film or fiber with nonlinear optical properties.

This invention relates to the production of functional and polymerizable coumarin dyes for the preparation of side-chain coumarin dye-substituted polymers which exhibit nonlinear optical (NLO) properties. More particularly, the present invention is directed to the provision of functional coumarin dyes, polymerizable coumarin dyes and side-chain coumarin dye-containing polymers useful for the fabrication of organic polymeric nonlinear optical materials.
The field of nonlinear optics is concerned with the interactions of electromagnetic fields with materials to produce new fields that are altered in phase, frequency, amplitude or other propagation characteristics from the incident field. See, for example, Y. R. Shen, "The Principles of Nonlinear Optics," John Wiley & Sons, N.Y., 1984. The best known nonlinear optical effect is second harmonic generation (SHG) or frequency doubling. Optically nonlinear materials are used in frequency doublers for lasers, optical communications and computing equipment, laser resistance devices, and in opto-electronic devices for other applications. See, for example, G. Boyd, J. Opt. Soc. of Am. B, 6(4) 685 (1989).
Nonlinear optical devices such as frequency doublers have been based almost exclusively on inorganic materials, e.g. lithium niobate (LiNbO.sub.3) and potassium dihydrogen phosphate (KDP). Crystalline organic materials, e.g. methylnitroaniline (MNA), are also under development. The disadvantages of these materials include relatively poor laser damage resistance and difficulties in preparation and fabrication into opto-electronic devices. Additionally, single organic crystals are brittle and difficult to grow.
Organic polymeric materials with large delocalized pi-electron systems exhibit very fast NLO responses, have large optical nonlinearities, and the chemical synthesis of these materials can be altered to optimize their desirable physical characteristics while preserving their NLO properties. See, for example, D. J. Williams, Agnew. Chem. Int. Ed. Engl., 23, 690 (1984). Polymeric NLO materials can have very good mechanical properties. They can be mechanically tough and easily fabricated or processed into thin film geometries that are very desirable for integration with microelectronics. See, for example, G. H. Cross, et al., "Polymeric integrated electro-optic modulators," Proceedings of the SPIE, 1177, 79 (1989).
Two basic approaches exist for the synthesis of optically nonlinear polymers. One approach is to prepare guest-host materials by simply dissolving polarizable moieties (chromophores or dyes) as the guest in a polymeric host. This physical or solid solution may be severely limited in concentration of the chromophore due to limited solubility of the dye molecule. The other approach is to synthesize polymers that have chromophores chemically attached as either side-chain or main-chain substituents. These dye-substituted polymers have several distinct advantages over guest-host materials including higher limiting concentrations of the chromophore, reduced mobility and enhanced orientational stability of the chromophore, and improved optical, thermal and mechanical properties. See, for example, K. D. Singer, et al., Appl. Phys. Lett., 53(19), 1800 (1988).
The methods used to synthesize dye-substituted polymers each have their separate advantages and disadvantages which should be considered. The attachment or substitution of chromophores onto preformed polymers is often complicated by limited reactivity of the chromophores and/or the polymer and/or poor solubility of the chromophore in the polymer. Steric interference or blocking of reactive sites on the polymer can also occur once some dye molecules have been attached to the polymer. The result is often poor control over the extend of reaction and less effective substitution of the polymer with chromophores. The polymerization of dye-substituted monomers is sometimes inhibited by side reactions, for example, in free radical polymerization the growing chain end may terminate by reaction with the dye.
The nonlinear optical properties of crystalline coumarin dyes have been previously reported and described, e.g. in U.S. Pat. No. 3,858,124. Thus, it has been disclosed that some coumarin dye single crystals have significant NLO properties, and that one specific example (7-diethylamino-4-methylcoumarin) showed frequency doubling ability that was at least as good as lithium niobate (LiNbO.sub.3). This crystalline coumarin also showed better laser damage resistance than LiNbO.sub.3. These reports also documented one major problem of coumarins that is common to many other crystalline materials used in NLO applications, that of difficulty in growing single crystals of sufficient size and high quality for evaluation. Further, nonpolymeric coumarin dye NLO materials, such as 7-dimethylamino-4-methylcoumarin, are limited in their usefulness by having poor mechanical properties.
Dye-containing polymers for NLO applications have been reported. See for example U.S. Pat. Nos. 4,795,664; 4,779,961; 4,755,574 and 4,579,915. However, to applicants' knowledge, no coumarin dye-containing polymers having nonlinear optical properties have to date been produced or reported.
One object of the invention accordingly is the provision of novel side-chain coumarin dye-containing polymers having nonlinear optical properties.
Another object is to provide side-chain coumarin in dye-containing polymers which also have good thermal, mechanical and optical properties.
A still further object is the provision of functional coumarin dyes and polymerizable coumarin dyes for the synthesis of the above coumarin dye-containing polymers having nonlinear optical properties.
Yet another object is to provide coumarin dyes which have functional hydroxyl groups or which are chemically attached to vinyl monomers for use in producing coumarin dye-containing polymers having NLO characteristics.

Coumarin dyes and side-chain coumarin dye-substituted polymers which exhibit nonlinear optical properties

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


A change procedure generating device 10 includes: a storage means 11 which stores, for each relation among constituent elements of a system, a plurality of instances of inter-state information which indicates relations among states of the constituent elements wherein a follow-up state limitation is included which represents a relation between a state transition of the constituent elements of the system and prescribed states to which the constituent elements transition after the state transition has been executed, and an appending means 12 which appends the relations among the states of the constituent elements to an inputted system configuration definition, using the inter-state information which corresponds to the relations among the constituent elements which are included in the configuration definition.

The purpose of change management is to reduce the labor of an administrator of a system to be changed and the labor of a change operator that is incurred when the system is changed and to reduce the influence on a user of the system to be changed.
In the case where the system to be changed is a complicated system including a plurality of components, the change operation becomes complicated. In the case where the change operation is complicated, the labor of the change operator or the labor of the administrator who supervises the operation of the change operator increases. That is, the influence on the user of the system to be changed also increases.
In particular, in the case where there is a limitation on the state (hereinafter referred to as "state limitation") between components included in the system, it is required to consider the order of change operations of respective components, and thus the change operation tends to be complicated. A state limitation between components may be, for example, in the case where a system to be changed includes a component A and a component B, such a relation between the two elements as that the component B is required to function normally in order for the component A to function normally.
In the case of the above example, the condition for the component A to normally function is that the component B functions normally beforehand. Hereinafter, the above relation is called a previous state limitation. In the operation procedure for configuring the system including the component A and the component B, there is an order such as that the component B is configured first and then the component A is configured.
Furthermore, in the case where the operation on a component affects another component, it is required to consider the order of the change procedure on the basis of the influence on the other component, and thus the change operation tends to be complicated.
For example, in the case where a system to be changed includes a component C and a component D and the component C is over the component D, replacement of the component D may require a procedure for incidentally moving the component C.
Hereinafter, the above relation is called a follow-up state limitation. The reason for this is because the above relation represents that the state of the component C changes afterwards, accompanying the replacement of the component D.
A system that automatically generates a plan of work required for change of a system while considering previous state limitations and follow-up state limitations as described above is called a change management system. In a change management system, information related to state limitations among components and information related to operation on components are defined in advance.
By using the above change management system, an administrator can efficiently generate an operation procedure effective for execution of complicated change operation. In addition, the operator can also efficiently execute the change operation in accordance with the generated effective operation procedure. That is, when the change management system is used, it is expected that the influence on the user of the system to be changed will also be reduced.
Many related researches and related products are already known with regard to the change management system as described above. For example, PTL 1 discloses a technology of generating a change operation procedure by defining a previous state limitation between operation states of each component.
In the method of expressing the state and limitation relation of components by a state transition diagram, generally, selection of the method of mutual conversion between system design information and the state transition diagram is a challenge. PTL 2 describes a method of efficiently converting a model having a state into a state transition diagram that can be easily handled.
NPL 1 describes a technology of automatically changing settings of a target system when setting parameters of each component and the order of setting actions are given.
NPL 2 and NPL 3 further prescribe a lifecycle framework which is used also for system construction in addition to system change. In the prescribed framework, it is assumed that a change procedure of a system is given by some external factor such as manual input. However, it is not assumed to directly relate the management of the system configuration and derivation of the change procedure.
NPL 4 describes a technology that predicts and updates relevant Amazon Web Services (AWS) (registered trademark) resources in a predictable manner, and allows developers and system administrators to easily generate and manage the AWS resources. A user using the technology described in NPL 4 can describe all dependency relations and parameters at the time of execution necessary for execution of AWS resources and applications of AWS resources by using a template.
In addition, PTL 3 describes a technology of confirming consistency between two or more change procedures, and presenting a correct work flow when inconsistency is confirmed. The technology described in PTL 3 is intended to solve conflicts that exist among a plurality of different change procedures and does not contribute to derivation of a change procedure for a single target to be changed.

Relation among states appending device, relation among states appending method, and relation among states appending program


A cable connector assembly (1) includes an insulative housing (21), a number of contacts (251) received in the insulative housing, a cable (3) including a number of wires (30) each including a conductive core (32) electrically connecting with a corresponding contact and a shielding braid (33) surrounding the conductive core, at least a shield members (24) mechanically and electrically connecting with the shielding braid of the cable, and a shell (20) retained to the insulative housing. At least a shield member includes a leg portion electrically connecting with at least a contact.

1. Field of the Invention
The present invention generally relates to a cable connector assembly, and particularly to a cable connector assembly having improved shield members.
2. Description of Related Art
Cable connector assemblies are commonly used to connect peripheral devices with a computer for performing data transmission therebetween. When the cable connector assemblies are used in high speed data transmission applications, the amount of electromagnetic (EMI) or radio frequency interference (RFI) increases. The EMI or RFI problem may be reduced by shielding. A conventional cable connector assembly as disclosed in U.S. Pat. No. 6,299,487 includes a plug connector and a cable connecting with the plug connector. The plug connector includes an insulative body portion, a shell partially insert-molded in the insulative body portion, and an internal terminal assembly received in the insulative body portion. The internal terminal assembly has a plurality of terminals connecting with distal ends of the cable.
However, the distal ends of the signal conductors of the cable are partially exposed outside, so the cross-talk occurs between the exposed signal conductors, thereby adversely affecting performance of the signal transmission. In addition, the shell of the plug connector has an integral and elongated hollow form with a front end and a rear end that are interconnected by a body portion. Significantly, it is difficult to completely insert the internal terminal assembly into the shell without inadvertently deflecting contact portions of the conductive terminals. In addition, since the internal terminal assembly is fully received in the shell, the cable should be soldered with the conductive terminals before the internal terminal assembly is inserted into the shell. Accordingly, a reliable connection between the cable and the conductive terminals is adversely affected during the insertion of the internal terminal assembly into the shell.
Hence, a cable connector assembly having improved shield members is desired to solve above-mentioned problems.

Cable connector assembly having improved shield members


A service depends on the location of a device. The device location is determined using DTV signals. More specifically, the device location is determined based on pseudo-ranges between the device and a plurality of digital television (DTV) transmitters and the pseudo-ranges are determined based on broadcast DTV signals received by the device from the DTV transmitters. Examples of DTV signals include the American Television Standards Committee (ATSC) signals, the European Telecommunications Standards Institute Digital Video Broadcasting-Terrestrial (DVB-T) signals and the Japanese Integrated Service Digital Broadcasting-Terrestrial (ISDB-T) signals.

1. Field of the Invention
This invention relates generally to position location and providing services based on position location. More specifically, it relates to providing services in cases where the position location is based on DTV signals.
2. Description of the Related Art
There have long been methods of two-dimensional latitude/longitude position location systems using radio signals. In wide usage have been terrestrial systems such as Loran C and Omega, and a satellite-based system known as Transit. Another satellite-based system enjoying increased popularity is the Global Positioning System (GPS).
Initially devised in 1974, GPS is widely used for position location, navigation, survey, and time transfer. The GPS system is based on a constellation of 24 on-orbit satellites in sub-synchronous 12 hour orbits. Each satellite carries a precision clock and transmits a pseudo-noise signal, which can be precisely tracked to determine pseudo-range. By tracking 4 or more satellites, one can determine precise position in three dimensions in real time, world-wide. More details are provided in B. W. Parkinson and J. J. Spilker, Jr., Global Positioning System-Theory and Applications, Volumes I and II, AIAA, Washington, D.C., 1996.
GPS has revolutionized the technology of navigation and position location. However in some situations, GPS is less effective. Because the GPS signals are transmitted at relatively low power levels (less than 100 watts) and over great distances, the received signal strength is relatively weak (on the order of −160 dBw as received by an omni-directional antenna). Thus the signal is marginally useful or not useful at all in the presence of blockage or inside a building.
There has even been a proposed system using conventional analog National Television System Committee (NTSC) television signals to determine position. This proposal is found in a U.S. patent entitled "Location Determination System And Method Using Television Broadcast Signals," U.S. Pat. No. 5,510,801, issued Apr. 23, 1996. However, the present analog TV signal contains horizontal and vertical synchronization pulses intended for relatively crude synchronization of the TV set sweep circuitry. Further, in 2006 the Federal Communication Commission (FCC) will consider turning off NTSC transmitters and reassigning that valuable spectrum so that it can be auctioned for other purposes deemed more valuable.
Knowledge of an object or individual's position is useful or even required in providing certain services. For example, emergency 911 services require knowledge of the caller's location. Similarly, navigation services typically require knowledge of the user's position. Other services, such as traffic reports and concierge services, can be provided without knowledge of an individual's location but can be greatly enhanced if the user's location is known.
However, the current position location systems have significant drawbacks that prevent or inhibit their use for many of these services. For example, the proposed NTSC system is not suitable for services that require high precision. In addition, since the NTSC transmitters may be turned off in 2006, services that require large initial investments are also less attractive since the time to recover the investment may be limited. GPS systems generally have higher precision than the NTSC system. However, the receivers are relatively complex and expensive, thus making the GPS approach inappropriate for services that require simple and/or low-cost receivers. In addition, the GPS signal is not particularly robust. GPS' low signal power makes it marginally useful in the presence of blockage or inside buildings. Its low bandwidth signal also makes it susceptible to multipath effects. The GPS satellites also travel at high speeds and significant Doppler aiding may be required to determine their exact location. At times, GPS geometries may be insufficient, leading to high Geometric Dilution of Precision (GDOP) and making it difficult to provide highly accurate position fixes. These factors make GPS unsuitable for many types of services.

Navigation services based on position location using broadcast digital television signals


The disclosure contains descriptions of various methods and systems for accelerating the execution of a virtual prototype simulation. Acceleration may be achieved, for example, by providing two or more redundant virtual communication paths for access made by virtual models of a virtual prototype of a hardware design to provide for both accelerated access transactions and time-accurate access transactions. A model having such redundant virtual communication paths is referred to herein as a “multimode model.”

A standard part of the design process for leading edge system on chip (SoC) designs is to create a prototype of the design before it is fabricated to silicon. This prototype can take several forms depending upon the design problem being addressed. It is not unusual for multiple prototypes to be created of the same design in order to best address specific design issues. There are two primary types of prototypes: physical prototypes and virtual prototypes.
Virtual prototypes form a software-only representation of a system on chip design. Depending upon the accuracy of the virtual prototype, it can execute at a full range of speeds. The virtual prototype can execute much faster than the actual hardware which it represents or much more slowly in cases where the virtual prototype is more accurately representing the behavior of the underlying hardware. The virtual prototype typically contains a collection of virtual prototype models, each virtual prototype model representing the various hardware components in the SoC design being modeled.
Whereas a hardware prototype necessarily represents all of the functionality of the modeled components, this is not necessarily true for virtual prototypes. It is common practice to abstract the timing details of a virtual prototype model in order to achieve faster execution speed. In some cases, the functionality of a virtual prototype model may also be abstracted to achieve faster performance or shorten model development time. Each component may be modeled at a different level of timing or functional accuracy depending upon the needs of the designer.
Depending upon the abstraction level of the individual models, virtual prototypes may be used at various points during the SoC design cycle. Accurate virtual prototypes can be used to perform architectural analysis, semiconductor intellectual property (IP) core selection and firmware development. A virtual prototype which does not have timing accuracy would likely not be used in this case due to lacking sufficient design detail. Higher speed, more abstract virtual prototypes can boot an operating system and execute application code, all before actual silicon is fabricated. While accurate virtual prototypes may be used for these tasks as well, it is rarely done due to the much slower execution times.
The accuracy of a virtual prototype type depends upon the accuracy of the virtual prototype models it contains. Indeed, there can be multiple virtual prototype models at different levels of abstraction contained in the same virtual prototype. Accuracy in this case does not typically refer to the functional accuracy of the prototype but more to the timing of the system. Most virtual prototypes will represent all of the functionality of the modeled component but with varying levels of timing accuracy. Most virtual prototypes are written based upon the transaction-level modeling (TLM) standard, produced by the Accellera Systems Initiative of Napa, Calif. and incorporated into the Institute of Electrical and Electronics Engineers Standards Association (IEEE-SA) 1666 standard for SystemC™. The TLM specification describes coding guidelines for a loosely-timed (LT) and approximately-timed (AT) level of abstraction. In a loosely timed virtual prototype, the models contained in the virtual prototype will either be completely untimed or will correlate their timing to actual execution time only at transaction boundaries. In an approximately timed virtual prototype, the virtual prototype model typically correlates to the system time at the boundary of every transaction and will often include additional timing information for actions which occur in the middle of a transaction. Commercially available loosely timed models include the Fast Models for ARM® (ARM Holdings of Cambridge, UK) and the Open Virtual Platforms™ (OVP™ of Oxfordshire, UK) designed by Imperas™ Software of Oxfordshire, UK.
Additionally, there are cycle accurate (CA) virtual prototypes which completely model the behavior of the underlying hardware. These models can either be hand-written to model this behavior and then validated against the actual design, or created automatically from the HDL representation of the component. For example, some commercially available cycle accurate virtual prototype models are created directly from HDL using the Carbon Model Studio product from Carbon Design Systems of Acton, Mass.
A typical system on chip design contains one or more processors communicating with one or more additional peripheral components such as a memory controller, an external interface block (e.g., Peripheral Component Interconnect Express (PCI-Express) bus, Universal Serial Bus (USB), serial bus, etc.) and/or additional controller logic (e.g., Direct Memory Access (DMA) controller, etc.). The individual hardware components of the system on chip design typically communicate over a system bus using memory-mapped accesses to various configurable regions. Thus, from a software perspective, communication with any hardware component can be achieved by reading or writing to memory regions or locations. It is common practice when creating a higher level virtual prototype of a system to leverage this communication mechanism and accelerate communications by bypassing peripheral components (e.g., the timing and functionality thereof) through direct memory accesses (e.g., to an identified memory region or register).
While it may be straightforward to create a high level model for accessing the memory contents by discounting the behavior and effects of the various intermediate peripheral components, not all functionality may be handled appropriately. For example, there are registers in the memory controller and functional details difficult to map into a high level model. Implementation details such as read-only or write-only register fields are easily mishandled as are potential side-effects of access transactions. For example, reading a register may cause three other registers to update some additional information. There is a need for a solution which provides adequate speed for aiding in software development, while providing accurate analysis for validating the behavior of the underlying hardware, including the effects of time-dependent access transaction behavior.

Multimode execution of virtual hardware models


Substantially dry free-flowing particles of amorphous precipitated silica have large sizes and large carrying capacities for organic liquids, and they contain little or no dust.

Amorphous precipitated silica has been used as a carrier for organic liquids such as, for example, vitamin E CAS 59-02-9!, vitamin E acetate CAS 58-95-7!, choline chloride CAS 67-48-1!, liquid organic additives for rubber such as for example hexakis(methoxymethyl)melamine CAS 3089-11-0!, and various organic phase change materials, i.e., an organic material which may be repeatedly transformed from the liquid phase to the solid phase and vice versa. The foregoing listing of organic liquids is by no means exhaustive, but exemplary; many other organic liquids may be employed for sundry purposes.
Situations often arise where it is more desirable to handle solids than to handle liquids. It is nonetheless ofttimes necessary to employ liquids. A major reason for using amorphous precipitated silica as a carrier for organic liquids is that the organic liquid can be absorbed by the precipitated silica and the combination thereafter handled as a free-flowing powder.
Different amorphous precipitated silicas have different carrying capacities for organic liquids. In most instances it is desirable for the carrying capacity of the silica to be as great as reasonably possible; this permits the quantity of both materials that must be handled to be minimized. It is at the same time desirable that the mixture of amorphous precipitated silica and absorbed organic liquid contain little or no dust.
The carrying capacity may be regarded as approximately the maximum amount of organic liquid that can be absorbed by the silica such that the mixture still retains the characteristics of a free-flowing powder. As a sample of the amorphous precipitated silica absorbs an organic liquid, the mixture changes from a free-flowing state to one of a semiplastic agglomeration, with an accompanying increase in viscosity. It will be appreciated that the carrying capacity of the amorphous precipitated silica for a particular organic liquid depends upon the identities of both the amorphous precipitated silica and the liquid. Also, the transition from a free-flowing powder to a semiplastic does not involve a sharp discontinuity when viscosity is plotted as a function of organic liquid content. Standard tests using a standard organic liquid are therefore used to characterize the carrying capacity, as will be discussed in more detail below.

Amorphous precipitated silica having large liquid carrying capacity


An organic electroluminescent display device includes first and second substrates facing and spaced apart from each other, the first and second substrates having a plurality of sub-pixel regions, a thin film transistor provided at each of the plurality of sub-pixel regions on an inner surface of the first substrate, a first electrode on an inner surface of the second substrate, an organic electroluminescent layer on the first electrode, a second electrode on the organic electroluminescent layer at each of the plurality of sub-pixel regions, and a connection pattern contacting the thin film transistor and the second electrode, wherein a melting temperature of the connection pattern is lower than a melting temperature of the second electrode.

1. Field of the Invention
The present invention relates to an organic electroluminescent display device and a method of fabricating an organic electroluminescent display device, and more particularly, to a dual panel-type organic electroluminescent device and a method of fabricating a dual panel-type organic electroluminescent display device.
2. Discussion of the Related Art
Among various different types of flat panel display (FPD) devices, organic electroluminescent display (OELD) devices have been developed because of their light-emitting properties, wide viewing angles, and good contrast ratios, as compared with the liquid crystal display (LCD) devices. Since a backlight device is not necessary in the OELD devices, the OELD devices can be light weight and thin. In addition, the OELD devices have low power consumption. When driving OELD devices, a low voltage direct current (DC) can be used, whereby rapid response speeds can be obtained. Since the OELD devices are solid state devices, unlike the LCD devices, they are sufficiently strong to withstand external impact and have greater operational temperature ranges. In addition, the OELD devices can be manufactured at low costs. For example, since only deposition and encapsulation apparatus are necessary for manufacturing the OELD devices, manufacturing processes of the OELD devices are simple in contrast to the LCD devices and in contrast to plasma display panel (PDP) devices.
During an operation method for the OELD devices, a passive matrix operating method that does not use additional thin film transistors (TFTs) is used. However, since passive matrix-type OELD devices have limited resolution, high power consumption, and reduced operational lifetime, active matrix-type OELD devices have been developed as next generation display devices that require high resolution and large display area.
In passive matrix-type OELD devices, scanning lines and signal lines are arranged to perpendicularly cross each in a matrix configuration, whereas in the active matrix-type OELD devices, a TFT is disposed at each pixel region to function as a switch to turn a first electrode connected to the TFT ON and OFF, and a second electrode is provided to face the first electrode.
In the passive matrix-type OELD devices, a scanning voltage is sequentially supplied to the scanning lines to operate each pixel. Accordingly, in order to obtain a required average brightness, an instantaneous brightness of each pixel during the selection period should reach a value resulting from multiplying the average brightness by the total number of scanning lines. Thus, since supplied voltage and current increase as the total number of the scanning lines increases, the passive matrix-type OELD devices are not adequate to display high resolution images over a large display area due to the high power consumption.
However, in active matrix-type OELD devices, a voltage supplied to the pixel is stored in a storage capacitor, thereby maintaining the voltage and driving the device until a voltage of next frame is supplied regardless of the total number of the scanning lines. Accordingly, an equivalent brightness is obtained using low supplied current, wherein the active matrix-type OELD device operates having low power consumption and high image resolution over a large display.
FIG. 1 is an equivalent circuit diagram of a basic pixel structure of an active matrix-type organic electroluminescent display device according to the related art. In FIG. 1, a scanning line 2 is arranged along a first direction, and a signal line 4 and a power line 6 are arranged along a second direction perpendicular to the first direction, thereby defining a sub-pixel region "Psub," wherein the signal line 4 and the power line 6 are spaced apart form each other. In addition, a switching TFT "Ts," which is commonly referred to as an addressing element, is connected to the scanning line 2 and the signal line 4, and a storage capacitor "CST" is connected to the switching TFT "Ts" and the power line 6. A driving TFT "TD," commonly referred to as a current source element, is connected to the storage capacitor "CST" and the power line 6, and an organic electroluminescent (EL) diode "DEL" is connected to the driving TFT "TD."
The organic EL diode "DEL" has an organic EL layer between an anode and a cathode. When a forward current is supplied to the organic EL diode "DEL," an electron and hole are recombined to generate an electron-hole pair through a P-N (positive-negative) junction between the anode, which provides the hole, and the cathode, which provides the electron. Since the electron-hole pair has an energy lower than an energy of the separated electron and hole, an energy difference is created between the recombination and the separated electron-hole pair, whereby light is emitted due to the energy difference.
Two different types of organic EL devices exist according to a direction of light emitted from the organic EL diode: passive matrix-type and active matrix-type.
FIG. 2 is a schematic cross sectional view of a bottom emission-type organic electroluminescent display device according to the related art, wherein one pixel region includes red, green, and blue sub-pixel regions. In FIG. 2, first and second substrates 10 and 30 face and are spaced apart from each other, wherein a peripheral portion of the first and second substrates 10 and 30 are sealed together by a seal pattern 40. A thin film transistor (TFT) "T" is formed at each sub-pixel region "Psub" on an inner surface of the first substrate 10, and a first electrode 12 is connected to the TFT "T." In addition, an organic electroluminescent layer 14 including luminescent materials of red, green, and blue is formed on the TFT "T" and the first electrode 12, and a second electrode 16 is formed on the organic electroluminescent layer 14. Accordingly, the first and second electrodes 12 and 16 supply an electric field to the organic electroluminescent layer 14. Although not shown, an adhesive and a moisture absorbent are formed on an inner surface of the second substrate 30 to shield the substrates from external moisture.
In the bottom emission-type OELD device, for example, the first electrode 12 functions as an anode and is made of a transparent conductive material, and the second electrode 16 functions as a cathode and is made of a metallic material of low work function. In addition, the organic electroluminescent layer 14 is composed of a hole injection layer 14a, a hole transporting layer 14b, an emission layer 14c, and a electron transporting layer 14d over the first electrode 12. The emission layer 14c has a structure where emissive materials of red, green, and blue are alternately disposed at each sub-pixel region "Psub."
FIG. 3 is a schematic cross sectional view of a sub-pixel region of a bottom emission-type organic electroluminescent display device according to the related art. In FIG. 3, a thin film transistor (TFT) "T" having a semiconductor layer 62, a gate electrode 68, and source and drain electrodes 80 and 82 is formed on a substrate 10. The source and drain electrodes 80 and 82 are connected to a power electrode 72 that extends from a power line (not shown) and an organic electroluminescent (EL) diode "DEL," respectively. In addition, a storage capacitor "CST" includes the power electrode 72 and a capacitor electrode 64 facing each other with an insulating layer disposed between the power electrode 72 and the capacitor electrode 64, wherein the capacitor electrode 64 is made of the same material as the semiconductor layer 62.
In FIG. 3, the TFT "T" and the storage capacitor "CST" are collectively referred to as array elements "A," whereas the organic EL diode "DEL" includes first and second electrodes 12 and 16 that face each other with an organic EL layer 14 disposed therebetween. The source electrode 80 of the TFT "T" is connected to the power electrode 72 of the storage capacitor "CST," and the drain electrode 82 of the TFT "T" is connected to the first electrode 12 of the organic EL diode "DEL."
FIG. 4 is a flow chart showing a fabricating process of an organic electroluminescent display device according to the related art. In FIG. 4, at step st1, array elements are formed on a first substrate, wherein the array elements include a scanning line, a signal line, a power line, a switching TFT, and a driving TFT. In addition, the signal line and the power line cross the scanning line and are spaced apart from each other, wherein the switching TFT is disposed at the crossing of the scanning and signal lines and the driving TFT is disposed at the crossing of the scanning and the power lines.
At step st2, a first electrode of an organic EL diode is formed over the array elements, wherein the first electrode is connected to the driving TFT of each sub-pixel region.
At step st3, an emission layer of the organic EL diode is formed on the first electrode. If the first electrode is designed to function as an anode, the organic EL layer can be composed of a hole injection layer, a hole transporting layer, an emission layer, and an electron transporting layer.
At step st4, a second electrode of the EL diode is formed on the organic EL layer. The second electrode is formed over an entire surface of the first substrate to function as a common electrode.
At step st5, the first substrate is encapsulated with a second substrate, wherein the second substrate protects the first substrate from external impact and prevents damage of the organic EL layer due to ambient air. In addition, a moisture absorbent may be included in an inner surface of the second substrate.
Accordingly, an organic EL device is fabricated through encapsulating the first substrate including the array elements and the organic EL diode with the second substrate. Since the production yield of the array elements multiplied by the production yield of the organic EL diode determines the production yield of the organic EL device, the production yield of the whole process is greatly restricted by the process for forming the organic EL diode. For example, even when the array elements are properly fabricated, the organic EL diode may not be properly fabricated, and thus, the production yield is adversely effected.
The bottom emission-type organic EL device has high encapsulation stability and high process flexibility. However, since the aperture ratio is restricted, it is difficult to incorporate the bottom emission-type organic EL device into a device having high image resolution. On the other hand, since the top emission-type organic EL device is easily designed and has high aperture ratio, the top emission-type organic EL device has some advantages, such as long operational lifetime. However, since the cathode is generally formed on the organic EL layer in the organic EL device of the top emission-type EL device, transmittance is reduced due to limitation of material selection such that optical efficiency is reduced. In addition, when a thin film protection layer is used to minimize the reduction of the transmittance, infiltration of ambient air is increased.

Dual panel-type organic electroluminescent display device and method of fabricating the same


The invention relates to a device and a process for acquiring bichromatic bar codes, with a two-dimensional sensor with electronic scanning. The height Hy of the scanned portion is modified between at least two successive scanning operations. Thus, the device is or may be adapted to the type and/or to characteristics not known in advance of the code to be read.

In known optoelectronic devices for acquiring machine-readable symbols, such as bar codes, a diaphragm has a circular aperture of small diameter so as to prevent defocusing of an image and/or to increase the depth of field of the device. The small diameter of the aperture, however, reduces the intensity of reflected light received at the sensor and, in practice, makes it necessary to use light sources having a high luminous intensity in order to compensate for the reduction in luminous intensity introduced by the aperture. However, high intensity light sources are expensive and lead to high power consumption.
While increasing the diameter of the aperture of the diaphragm increases the quantity of light received by the sensor, the increase in diameter also reduces the depth of field of the device, thereby reducing the overall efficiency of the device.
One attempt at solving these problems involves producing an optoelectronic device as described in patent application EP-61000, where the diaphragm has an aperture having an asymmetrical elongation along an axis orthogonal to the axis of the bar code, such as an aperture of rectangular, rhombic or elliptical shape. This effectively increases the sensitivity of optoelectronic devices, which is proportional to the ratio of collected flux to reflected flux. As a result, the depth of field of these devices may be increased without significantly affecting the intensity collected on the sensor, thereby increasing the efficiency of these devices. The relatively large dimensions of the diaphragm aperture, however, makes it necessary to use an asymmetrical diaphragm, and optical means for forming the image on the sensor having dimensions greater than those of conventional optical means, which increases production costs and complexity greater than those of conventional diaphragms and optical means.
Another attempt at solving these problems involves producing optoelectronic devices as described in International Patent Applications WO-9620454 and WO-9847377, where the optical means are adapted to obtain, in the plane (XOZ) parallel to the optical plane, a magnification m1 greater than the magnification m2 in the plane (YOZ) perpendicular to the optical plane.
This approach, which can also be associated with that described in the patent EP-61000, leads to an increase, along axes parallel to the bars of the bar codes, in the size of the illumination surface of the bar codes whose image is reflected on the sensor, and therefore to an increase in the sensitivity of the optoelectronic device. It should be noted, furthermore, that since this increase in the sensitivity of the device results from the mere design of the optical means and not from the dimensions of the diaphragm aperture, a device of this type may be equipped with a conventional diaphragm with a circular aperture of small dimensions and therefore with low-cost optical means of conventional dimensions which is easy to produce.
With all these devices in which the diaphragm and/or the optical means do not form a symmetrical system generated by revolution round the optical axis, the improvement in sensitivity is effective only when the optical plane (plane containing the optical axis and the scanning direction) coincides exactly with the nominal direction of reading of the bar code (perpendicular to the code bars and spaces). Now, as the bar code and/or the optoelectronic device in practice have unfixed orientations in space, this condition is rarely fulfilled. Thus, a device of this type is extremely sensitive to alignment errors between the optical plane and the normal direction of reading and is therefore difficult to handle.
More generally, known optoelectronic devices for acquiring machine-readable symbols can be configured for predetermined characteristics of the symbols to be acquired and/or for predetermined positioning relative to the device. However, these optoelectronic devices have inferior performance if the symbol does not have these expected characteristics or if the positioning is not perfect. As a result, they suffer from a significant reading failure rate, in particular in the case of plurimonodimensional symbols such as PDF 417 codes.
U.S. Pat. No. 5,654,533 describes a two-dimensional symbol reader comprising a two-dimensional sensor and an automatic diaphragm of which the diameter varies to allow appropriate illumination of the sensor. This device does not attempt, and cannot solve the above mentioned problem since, with this device, correct illumination of the sensor corresponds to a diaphragm that produces an inadequate depth of field. Furthermore, this device is limited to the acquisition of bi-dimensional symbols by imagery, in other words by obtaining and analyzing two-dimensional images.
WO-98.16896 describes a two-dimensional symbol reader comprising both an electronic scanning device having a two-dimensional sensor and a laser scanner device. This mixed reader enables the user to select one of the two devices depending on the symbol to be read. It is however very complex and therefore expensive, fragile and awkward to use. In particular, the embodiments disclosed herein avoid the use of laser devices incorporating moving parts.
At present, therefore, there is no optoelectronic device for acquiring machine-readable symbols, such as bar codes, with electronic scanning which has satisfactory performance, particularly in depth of field, which allows the acquisition of symbols with any characteristics which may be not be known in advance. For example, bar dimensions, bar contrast, type of codes, monodimensional or plurimonodimensional codes (in other words formed by a plurality of monodimensional bar codes) such as the PDF 417 codes, or two-dimensional codes, etc.

This patent is subject to a terminal disclaimer.

Optoelectronic device and process for acquiring symbols, such as bar codes, using a two-dimensional sensor