A wireless receiver (74) for receiving signals from a transmitter (72). The transmitter comprises a plurality of transmit antennas (TAT1′, TAT2′) for transmitting the signals, which comprise respective independent streams of symbols. Additionally, interference occurs between the respective streams. The receiver comprises a plurality of receive antennas (RAT1′, RAT2′) for receiving the signals as influenced by a channel effect between the receiver and the transmitter. The receiver also comprises circuitry (80) for multiplying the signals times a conjugate transpose of an estimate of the channel effect and times a conjugate transpose of a linear basis transformation matrix. The receiver also comprises circuitry (84) for selecting the linear basis transformation matrix from a finite set of linear basis transformation matrices. Lastly, the receiver comprises circuitry (88) for removing the interference between the respective streams.

The present embodiments relate to wireless communications systems and, more particularly, to transmitters and receivers with multiple transmit and multiple receive antennas, respectively.
Wireless communications are prevalent in business, personal, and other applications, and as a result the technology for such communications continues to advance in various areas. One such advancement includes the use of spread spectrum communications, including that of code division multiple access ("CDMA") and wideband code division multiple access ("WCDMA") cellular communications. In such communications, a user station (e.g., a hand held cellular phone) communicates with a base station, where typically the base station corresponds to a "cell." CDMA communications are by way of transmitting symbols from a transmitter to a receiver, and the symbols are modulated using a spreading code which consists of a series of binary pulses. The code runs at a higher rate than the symbol rate and determines the actual transmission bandwidth. In the current industry, each piece of CDMA signal transmitted according to this code is said to be a "chip," where each chip corresponds to an element in the CDMA code. Thus, the chip frequency defines the rate of the CDMA code. WCDMA includes alternative methods of data transfer, one being frequency division duplex ("FDD") and another being time division duplex ("TDD"), where the uplink and downlink channels are asymmetric for FDD and symmetric for TDD. Another wireless standard involves time division multiple access ("TDMA") apparatus, which also are used by way of example in cellular systems. TDMA communications are transmitted as a group of packets in a time period, where the time period is divided into slots (i.e., packets) so that multiple receivers may each access meaningful information during a part of that time period. In other words, in a group of receivers, each receiver is designated a slot in the time period, and that slot repeats for each group of successive packets transmitted to the receiver. Accordingly, each receiver is able to identify the information intended for it by synchronizing to the group of packets and then deciphering the time slot corresponding to the given receiver. Given the preceding, CDMA transmissions are receiver-distinguished in response to codes, while TDMA transmissions are receiver-distinguished in response to time slots.
Since CDMA and TDMA communications are along wireless media, then the travel of those communications can be affected in many ways, and generally these effects are referred to as the channel effect on the communication. For example, consider a transmitter with a single antenna transmitting to a receiver with a single antenna. The transmitted signal is likely reflected by objects such as the ground, mountains, buildings, and other things that it contacts. In addition, there may be other signals that interfere with the transmitted signal. As a result, when the transmitted communication arrives at the receiver, it has been affected by the channel effect. As a result, the originally-transmitted data is more difficult to decipher due to the added channel effect.
As a result of the channel effect, various approaches have been developed in an effort to reduce or remove that effect from the received signal so that the originally-transmitted data is properly recognized. In other words, these approaches endeavor to improve signal-to-noise ratio ("SNR"), thereby improving other data accuracy measures (e.g., bit error rate ("BER"), frame error rate ("FER"), and symbol error rate ("SER")). One such approach is referred to in the art as a closed loop system, meaning the receiver feeds back information, relating to the channel effect, to the transmitter so that the transmitter can modify its future transmissions so as to compensate for the channel effect. This process repeats so that future changes in the channel effect are again fed back from the receiver to the transmitter, and the transmitter thereafter responds to the updated information relating to the channel effect. Another approach is referred to in the art as an open loop system. In the open loop system, the transmitter also attempts to adjust its transmissions to overcome the channel effect, but the system is termed "open" because there is no feedback from the receiver to the transmitter.
By way of further background, the wireless art also includes other approaches to assist in symbol recovery in view of the channel effect as well as other signal-affecting factors. One such approach is termed antenna diversity, which refers to using multiple antennas at either the transmitter, receiver, or both. For example, in the prior art, a multiple-antenna transmitter is used to transmit the same data on each antenna, with a single antenna receiver then exploiting the differences in the received signals from the different antennas so as to improve SNR. The approach of using more than one transmit antenna at the transmitter is termed transmit antenna diversity, where similarly using more than one receive antenna at the receiver is termed receive antenna diversity. More recently, antenna diversity has been combined with the need for higher data rate. As a result, multiple antenna transmitters have been devised to transmit different data, that is, the data to be transmitted is separated into different streams, with one transmit antenna transmitting a first stream and another transmit antenna transmitting a second stream that is independent from the first stream, and so forth for each of the multiple transmit antennas. In such a case, the receiver typically includes the same, or a greater, number of antennas as the transmitter. Of course, each receiver antenna receives signals from all of the transmit antennas, and these signals also are affected by respective channel effects. Thus, the receiver operates to exploit the use of its multiple antennas as well as recognizing the use of multiple transmit antennas in an effort to fully recover the independent data streams transmitted by the transmitter.
One type of multiple transmit antenna and multiple receive antenna system is known in the art as a multi-input multi-output ("MIMO") system and is shown generally as system 10 in the electrical and functional block diagram of FIG. 1. In the example shown in FIG. 1, system 10 is a CDMA system. System 10 includes a transmitter 12 and a receiver 14. For the sake of convenience, each of transmitter 12 and receiver 14 is discussed separately, below.
Transmitter 12 receives information bits Bi at an input to a channel encoder 16. Channel encoder 16 encodes the information bits Bi in an effort to improve raw bit error rate, where various encoding techniques may be used. The encoded output of channel encoder 16 is coupled to the input of an interleaver 18. Interleaver 18 operates with respect to a block of encoded bits and shuffles the ordering of those bits so that the combination of this operation with the encoding by channel encoder 16 exploits the time diversity of the information, and then those bits are output to a modulator 20. Modulator is in effect a symbol mapper in that it converts its input bits to symbols, each designated generally as si. The converted symbols si may take various known forms, and the symbols si may represent various information such as user data symbols, pilot symbols, and control symbols. For the sake of illustration, a stream of two such symbols, s1 followed by s2, are shown as output by modulator 20. Each symbol si is coupled to a serial-to-parallel converter 22. In response, serial-to-parallel converter 22 receives the incoming symbols and outputs them in parallel streams along its outputs 22o1 and 22o2 to a spreader 24. Spreader 24 modulates each data symbol by combining it with, or multiplying it times, a CDMA spreading sequence which can be a pseudo-noise ("PN") digital signal or PN code or other spreading codes (i.e., it utilizes spread spectrum technology), and it may be a single code or a multicode approach where in a MIMO system the code(s) is the same for each transmitting antenna. In a single code instance, the different symbol streams to be transmitted by each transmit antenna TAT1 and TAT2 is multiplied times the same code. In a multicode instance, each stream output 22o1 and 22o2 is further divided into ds streams. Each of the ds streams is multiplied times a different and orthogonal code from a set of ds codes, where the same set of codes applies to each stream output 22o1 and 22o2. Also for each set of streams, after the multiplication times the codes, the resulting products are summed and output to a respective one of transmit antennas TAT1 and TAT2. In any event, the spreading sequence facilitates simultaneous transmission of information over a common channel by assigning each of the transmitted signals a unique code during transmission. Further, this unique code makes the simultaneously-transmitted signals over the same bandwidth distinguishable at receiver 14 (or other receivers). In any event, the outputs 24o1 and 24o2 of spreader 24 are connected to respective transmit antennas TAT1 and TAT2. For example, in a total stream ST of spread symbols s1, s2, s3, s4, spreader 24 outputs a first stream S1 consisting of spread symbols s1 and s3 to transmit antenna TAT1 and spreader 24 outputs a second stream S2 consisting of spread symbols s2 and s4 to transmit antenna TAT2.
Receiver 14 includes a first receive antenna RAT1 and a second receive antenna RAT2 for receiving communications from both of transmit antennas TAT1 and TAT2. Due to the wireless medium between transmitter 12 and receiver 14, each of receive antennas RAT1 and RAT2 receives signals from both of the transmit antennas TAT1 and TAT2. To further illustrate this effect, FIG. 1 illustrates a different channel effect value hab from each transmit antenna to each receive antenna, where the first subscript a designates the receive antenna (i.e., 1 for RAT1 and 2 for RAT2), and the second subscript b designates the transmit antenna (i.e., 1 for TAT1 and 2 for TAT2). For sake of reference as well as further analysis below, the received signals are designated r1 and r2 as received by antennas RAT2 and RAT2 respectively. Moreover, given the preceding description of the channel effect, it now may be observed that each of r1 and r2 includes the transmitted symbols, as influenced by the channel effects; additionally, a noise element w2 also will exist in r1 and r2 and, thus, each of these values may be represented according to the following respective Equations 1 and 2, which relate to the receipt of the first symbols s1 and s2 from streams S1 and S2, respectively:r1=h11s1+h12s2+w1  Equation 1r2=h21s1+h22s2+w2  Equation 2Thus, Equations 1 and 2 demonstrate that each receive antenna receives a signal having one component pertaining to one transmitted stream (e.g., s1) and another component pertaining to the other and independently-transmitted stream (e.g., s2).
Given the values r1 and r2 in Equations 1 and 2, they are connected to a despreader and signal separation block 32. The despreader function of block 32 operates according to known principles, such as by multiplying the CDMA signal times the CDMA code for receiver 14 and resolving any multipaths. In addition, since two separate signals are input, then the signal separation function of block 32 separates these signals into estimates of the transmitted symbol streams S1 and S2, and for sake of reference such estimates are shown as Ŝ1 and Ŝ2, respectively. In CDMA, the signals may be separated according to various known techniques, such as zero forcing or minimum mean square error, each being either a 1-shot (i.e., linear) or iterative operation, or alternatively a maximum likelihood approach may be implemented. The symbol stream estimates are connected to a parallel-to-serial converter 34, which converts the two parallel streams into a single total estimated symbol stream, ŜT. The estimated symbol stream is connected to a demodulator 36, which removes the modulation imposed on the signal by modulator 20 of transmitter 12. The output of demodulator 36 is connected to a deinterleaver 38. Deinterleaver 38 performs an inverse of the function of interleaver 18 of transmitter 12, and the output of deinterleaver 38 is connected to a channel decoder 40. Channel decoder 40 further decodes the data received at its input, typically operating with respect to certain error correcting codes, and it outputs a resulting stream of decoded symbols. Finally, the decoded symbol stream output by channel decoder 40 may be received and processed by additional circuitry in receiver 14, although such circuitry is not shown in FIG. 1 so as to simplify the present illustration and discussion.
From the preceding, it may be observed that MIMO system 10 has as a basic characteristic that it transmits independent data streams to a receiver such as receiver 14. However, each stream interferes with the other, and receiver 14 receives signals that include components from each of the independently-transmitted symbol streams. The advantage of MIMO system 10 is that it can achieve higher data rate for a given modulation scheme, for example because it simultaneously transmits different streams of data along different transmit antennas. Alternatively, MIMO system 10 allows the use of lower order modulation given the data rate requirement. The disadvantage, however, is that greater channel diversity gain may be achieved in other systems.
Another type of theoretical system proposed in the art is a closed loop system wherein channel information is communicated from a receiver to a transmitter and the transmitter communicates via the channel eigenmodes; such a system is referred to in this document as an eigenmode system and one is shown in electrical and functional block diagram form generally as eigenmode system 50 in FIG. 2. System 50 includes a transmitter 52 and a receiver 54. Within these devices, and for the sake of simplifying the following discussion, portions of transmitter 52 and a receiver 54 are shown to include various of the same or comparable blocks as system 10 in FIG. 1; these blocks therefore use the same reference identifiers in both Figures and the reader is assumed to be familiar with the earlier-described concepts relating to such blocks. Accordingly, the following focuses on those blocks which differ in eigenmode system 50 as compared to system 10, as discussed below.
Looking to transmitter 52, the symbols are output from serial-to-parallel converter 22, in respective symbols streams, along outputs 220; and 22. Each of outputs 22o1 and 22o2 is connected as a first multiplicand to a respective multiplier 561 and 562, and each of multipliers 561 and 562 receives as a second multiplicand a square root of a power weighting factor p1 and p2, respectively. The outputs of multipliers 561 and 562 are connected to a matrix multiplication block 58. Matrix multiplication block 58 multiplies the products from multipliers 561 and 562 times a matrix U, where U is detailed later after a presentation of the channel effect as characterized by a matrix, H. At this point, for the sake of designation, let the resulting products from matrix multiplication block outputs 58o1 and 58o2 be represented as x1 and xZ, as shown in FIG. 2, and thus in response to the various operations on symbols s1 and s2, respectively. The outputs 58o1 and 58o2 of matrix multiplication block 58 are connected to spreader 24, after which the spread signals are connected to transmit antennas TAT3 and TAT4 for transmission to receiver 54.
Receiver 54 includes receive antennas RAT3 and RAT4 for receiving signals r1 and r2 from transmit antennas TAT3 and TAT4. These signals are first despread by a despreader 32. Further, in a way comparable to MIMO system 10 and discussed above with respect to Equations 1 and 2, the signals received by each of receive antennas RAT3 and RAT4 include components from both of the transmit antennas TAT3 and TAT4, as influenced by channel effects hab from each transmit antenna to each receive antenna. To further explain eigenmode system 50 and the additional processing following despreader 32, let the following matrix H, as shown in Equation 3, include each of these channel effects:
                    H        =                  [                                                                      h                  11                                                                              h                  12                                                                                h                  21                                                                              h                  22                                                              ]                                    Equation                                                  3            Further, a vector, r, is now defined to include each of the received signals r1 and r2, according to the following Equation 4:
                              r          _                =                              H                                      [                                                                                x                      1                                                                                x                      2                                                                                ]                                +                      [                                                                                w                    1                                                                                w                    2                                                                        ]                                              Equation                                                  4            where in Equation 4, H is the channel effect matrix of Equation 3, x1 and x2 are the signals transmitted by transmitter 52, and w1 and w2 are the noise components in the received signals. Further, let the transmitted signals and noise signals be defined as the vectors in the following Equations 5 and 6:
                              x          _                =                  [                                                                      x                  1                                                                                x                  2                                                              ]                                    Equation                                                  5                                          w          _                =                  [                                                                      w                  1                                                                                w                  2                                                              ]                                    Equation                                                  6            Accordingly, Equation 4 can be re-written in vector form by substituting in the conventions of Equations 5 and 6 to yield the following Equation 7:r=Hx+w  Equation 7
Having established the various preceding designations, attention is now returned to additional aspects of receiver 54, after which the preceding Equations are further developed to reflect the overall operation of eigenmode system 50. The signals r1 and r2 are connected from receive antennas RAT3 and RAT4, through despreader 32, to a matched filter block 60. Matched filter block 60 multiplies these incoming signals times a matrix that represents a conjugate transpose of an estimate of the channel effect H shown in Equation 3 and, thus, this conjugate transpose is designated HH and since the estimate is involved it is shown as ĤH. Note that the channel effect used for this computation is generally determined by receiver 54 by estimating the channel effect on pilot symbols it receives from transmitter 52. In the art, the operation of matched filter 60 is sometimes referred to as part of a different block such as a rake, rake filter, space time rake filter, signal separation block, or the like. In any event, the output of matched filter block 60 may be shown as the vector y in the following Equation 8:y=ĤHr  Equation 8
Next, Equation 7 may be substituted for r in Equation 8, and assuming the estimate of H is a fairly accurate estimate then the value HH may be used for ĤH, yielding the following Equation 9:y=HHHx+HHw  Equation 9
In Equation 9, the result of HHH is Hermitian symmetric and non-negative definite. Hence, from matrix theory, HHH may be re-stated according to eigen decomposition as shown in the following Equation 10:HHH=UΛUH  Equation 10
Eigen decomposition indicates that the factor U from Equation 10 is defined as shown in the following Equation 11:U=[u1,u2]  Equation 11In Equation 11, u1 and u2 are referred to as eigenvectors, that is, they are the eigenvectors of HHH; sometimes in the wireless art, such vectors are instead referred to as eigenmnodes due to the transmission in response to these values as described later. The eigenvectors are further defined according to the following Equations 12 and 13:
                                          u            _                    1                =                  [                                                                      u                  11                                                                                u                  12                                                              ]                                    Equation                                                  12                                                      u            _                    2                =                  [                                                                      u                  21                                                                                u                  22                                                              ]                                    Equation                                                  13            Additionally, the eigenvectors have the following properties of Equations 14 and 15:u1Hu1=u2Hu2=1  Equation 14u1Hu2=u2Hu1=0  Equation 15
From the above, the two eigenvectors u1 and u2 are orthogonal and perpendicular, and as shown below they also are non-interfering with one another, which allows transmission of signals in response to these eigenvectors so that those signals do not interfere with one another. Additionally, the matrix U may be re-written with the eigenvectors u1 and u2 in its columns, as shown in the following Equation 16:
                    U        =                  [                                                                      u                  11                                                                              u                  12                                                                                u                  21                                                                              u                  22                                                              ]                                    Equation                                                  16
Eigen decomposition also indicates that the factor A from Equation 10 is defined as shown in the following Equation 17:
                    Λ        =                  [                                                                      λ                  1                                                            0                                                                    0                                                              λ                  2                                                              ]                                    Equation                                                  17            In the diagonal matrix of Equation 17, and in connection with HHH, λ1 and λ2 are referred to as its eigenvalues, and they are real numbers greater than or equal to zero. Additionally, each eigenvalue λ1 and λ2 is linked to a corresponding one of the eigenvectors u1 and u2, respectively, and are analogous to a gain factor for the corresponding eigenvector. This relationship can similarly be shown by re-writing Equation 10 as the following Equation 18:
                                          H            H                              H                =                              U                                                                          Λ                                                                                U              H                                =                                    ∑                              i                =                1                            2                                                                                λ                i                                                                            u                  _                                i                                                                            u                  _                                i                H                                                                        Equation                                                  18            From Equation 18, one skilled in the art will, therefore appreciate the correspondence of the eigenvalue λ1 with the eigenvector u1 and the correspondence of the eigenvalue λ2 with the eigenvector u2.
Continuing now with receiver 54, the resulting vector y from matched filter 60 is output to a matrix multiplication block 62. Matrix multiplication block 62 multiplies its vector input times the conjugate transpose of the matrix U of Equation 16, that is, the multiplicand is therefore UH. The result of this operation, as further detailed below, provides a vector z that includes separate output symbols z1 and z2, and which correspond to the independently-transmitted signals x1 and x2, respectively (and, hence, also to symbols s1 and s2, respectively). Thus, the operation of matrix multiplication block 62 may be represented by the following Equation 19:z=UHy  Equation 19
From the above, it has been shown that transmitter 52 includes a matrix multiplication block 58 that multiplies parallel input symbols streams times the matrix U, and receiver 54 includes a matrix multiplication block 58 that multiplies its input signals times the conjugate transpose of that matrix, namely, UH. These aspects are now further explored so as to demonstrate how these operations provide for the transmission of independent symbol streams and the recovery of those streams at receiver 54 without interference between them.
Returning to transmitter 52, recall that symbols s1 and s2 are multiplied times √{right arrow over (p1)} and √{right arrow over (p2)}, respectively. This operation may be represented mathematically by defining the matrix, Π, in the following Equation 20:
                    Π        =                  [                                                                                p                    1                                                                              0                                                                    0                                                                                p                    2                                                                                ]                                    Equation                                                  20            Further, let the vector s be defined to include the symbols s1 and s2, and let the vector x be defined to include the transmitter outputs x1 and x2, then the output of transmitter 52 is as shown in the following Equation 21:x=UΠs  Equation 21
Returning to receiver 54, recall that blocks 60 and 62 perform multiplications times HH and UH, respectively. The effect of these multiplications now may be appreciated further, particularly by substituting Equation 10 into Equation 9, to yield the vector shown in the following Equation 22:y=UΛUHx+HHw  Equation 22Next, Equation 22 may be substituted into Equation 19 for y to define the output vector, z, from multiplication block 62, as is shown in the following Equation 23:z=UH(UΛUHx+HHw)=UHUΛUHx+UHHHw  Equation 23Equation 23 can be reduced due to the property of the eigenvector matrix U as shown in the following Equation 24:
                                          U            H                              U                =                  I          =                      [                                                            1                                                  0                                                                              0                                                  1                                                      ]                                              Equation                                                  24            From Equation 24, therefore, the identity matrix result, I, may be removed from Equation 23, and additionally Equation 21 may be substituted into Equation 23 for x, while also disregarding the noise term relating to the vector w, with the result shown in the following Equation 25:z=ΛUHx=ΛUHUΠs=ΛΠs  Equation 25
Having developed Equation 25 as a result of the two matrix multiplications (i.e., UH, HH) in receiver 54, it is now shown how the eigenmode transmissions do not interfere with one another. Specifically, Equation 25 may be fully written out and simplified according to the following Equation 26:
                              [                                                                      z                  1                                                                                z                  2                                                              ]                =                                            [                                                                                λ                      1                                                                            0                                                                                0                                                                              λ                      2                                                                                ]                                                  [                                                                                p                        1                                                                                0                                                                                0                                                                                p                        2                                                                                ]                                                                                [                                                                                d                        1                                                                                d                        2                                                                                ]                            =                                                                    [                                                                                λ                              1                                                                                p                                1                                                                                0                                                                                0                                                                                λ                              2                                                                                p                                2                                                                                ]                                                                          [                                                                                s                            1                                                                                s                            2                                                                                ]                                                  =                                  [                                                                                λ                            1                                                                                s                            1                                                                                p                              1                                                                                λ                            2                                                                                s                            2                                                                                p                              2                                                                                ]                                                                                Equation                                                  26            From Equation 26, it may be seen that as a result of the multiplication by blocks 60 and 62, z1 is a value that is responsive to s1 irrespective of s2, and similarly, z2 is a value that is responsive to s2 irrespective of s1. In other words, there is no interference as between s1 and s2, as transmitted to receiver 54. This result occurs due to the orthogonality property shown in Equation 24, as realized by the multiplication of the transmitted signals by U in block 52 and the later multiplication of the received signals by UH in block 62. As a result, following block 62, and unlike certain other wireless systems, there is no additional interference cancellation block in receiver 54.
While eigenmode system 50 provides communication of independent symbol streams and does not require interference cancellation at the receiver, note that transmitter 52 necessarily requires sufficient channel state information to determine the matrix U. In an FDD system where the uplink and downlink channels are asymmetric, then receiver 54 must therefore provide this information to transmitter 52 in some form. For example, receiver 54 must either receive the eigenvectors and eigenvalues from receiver 54, or it must receive sufficient information from receiver 54 so that it may determine these values on its own from the received information. However, for FDD systems, the requirement of feeding back sufficient state information may itself not be feasible due to the high amount of bandwidth that would be required to feed back such information. For example, when four transmit antennas are used, then possibly four eigenvectors must be computed by receiver 54 and fed back, where each eigenvector is represented by four coefficients (including the power weighting eigenvalue for each stream), representing a total of 16 coefficients. Assuming that each coefficient is quantized to NQ bits, this requires a 16×NQ bit feedback resource. However, in the current WCDMA standard, only 1 feedback bit per slot is sent to the transmitter. Thus, to implement an eigenmode system even for NQ=2, this would result in an intrinsic delay of 32 slots, which therefore is not acceptable even in slow fading channels. In addition, trade-offs may be realized by transmitting only via the best channel eigenvector which gives the maximum diversity gain at the expense of low data rate, or one may utilize all the channel eigenvectors to transmit different data streams and thus increase the data rate, while losing diversity gain and hence decreasing performance. In theory, to partially overcome this loss of diversity, a power allocation scheme across eigenvectors can be used to reduce the channel variation caused by the fading. However, for FDD systems where the requirement of feeding back state information may itself not be feasible due to the high amount of bandwidth it consumes, this additional amount of feedback makes the total amount of return information even less feasible. Moreover, if the feedback rate is fixed, such a proposal would increase the delay time before transmitter 52 acquires the eigenvectors. This then results in a large performance loss, particularly when the channel is time varying.
In view of the above, there arises a need to address the drawbacks of the prior art and the preceding proposals, as is achieved by the preferred embodiments described below.

Closed loop multiple transmit, multiple receive antenna wireless communication system


A zoom optical system provided, in order from a reduction side toward a magnification side, with: a first lens unit having positive optical power; a second lens unit having positive optical power; a third lens unit having positive optical power; and a fourth lens unit having negative optical power; wherein the interval between adjacent ones of the first, second, third and fourth lens units is varied during zooming, and in an entire zooming range, a magnification side conjugate position relative to a reduction side conjugate position, and the position of the pupil of the zoom optical system relative to the reduction side conjugate position are substantially immovable.

1. Field of the Invention
This invention relates to a zoom optical system for use in an optical apparatus such as an image projecting apparatus or an exposing apparatus.
2. Related Background Art
Some of such optical apparatuses as mentioned above require a zoom optical system excellent in telecentricity on the object side, and excellent in the invariability of the positions of the object surface, the image plane and the exit pupil relative to the variation of the focal length.
For example, Japanese Patent Application Laid-open No. 2002-207167 discloses, as a zoom optical system suitable for an illuminating optical system mounted on a projection exposing apparatus, a zoom optical system in which as the focal length becomes shorter, a lens unit having negative refractive power or a lens unit including a lens element having strong negative refractive power is moved toward the object side, whereby the positions of the object surface, the image plane, the entrance pupil and the exit pupil are made immovable relative to the variation of the focal length.
Also, Japanese Patent Application Laid-open No. 2002-055279 discloses a zoom optical system suitable for a transmitting optical system in an illuminating optical system mounted on a projection exposing apparatus. This zoom optical system has at least four lens units, and at least three lens units are moved, whereby during zooming from the wide angle end to the telephoto end, the refractive power arrangement of positive, negative and positive in succession from the object side is approached from the refractive power arrangement of negative, positive and positive or positive, positive and negative in succession from the object side, whereby the positions of the object surface, the image plane, the entrance pupil and the exit pupil are made immovable relative to the variation of the focal length.
Now, it is also conceivable for the zoom optical system disclosed in Japanese Patent Application Laid-open No. 2002-207167 or Japanese Patent Application Laid-open No. 2002-055279 to be used in the projection optical system of an image projecting apparatus for enlarging and projecting the image of an original formed on a liquid crystal panel or a portion of the projection optical system.
However, when a liquid crystal panel is disposed on the reduction side focal plane of the zoom optical system of Japanese Patent Application Laid-open No. 2002-207167, the back focus cannot be sufficiently secured, and a space for disposing a color synthesizing member therein cannot be secured on the reduction side. In a so-called three-plate type image projecting apparatus, a color synthesizing member for synthesizing three red, green and blue color lights is disposed on the reduction side of the zoom optical system, but if as described above, the back focus cannot be sufficiently secured, it will become impossible to secure the space for disposing the color synthesizing member therein.
Also, in the zoom optical system disclosed in Japanese Patent Application Laid-open No. 2002-207167, the lens unit most adjacent to the reduction side has negative refractive power, and as the focal length becomes shorter, a lens unit having positive refractive power and disposed more adjacent to the magnification side than the negative lens unit is moved toward the magnification side, and the interval between the two lens units is increased. Therefore, the effective diameter of this positive lens unit becomes large. Further, since the lens unit most adjacent to the reduction side has negative refractive power, the numerical aperture (NA) of the reduction side becomes small.
In Japanese Patent Application Laid-open No. 2002-207167, there is also disclosed a case where the lens unit most adjacent to the reduction side is given positive refractive power, but as the focal length becomes shorter, this lens unit is greatly moved toward the magnification side and therefore, if the NA of the reduction side is made great, the effective diameter of this lens unit will become large.
That is, in this zoom optical system, in the state of a minimum focal length (wide), a plurality of lens units deviate toward an aperture stop side, and are moved toward the reduction side focal plane as the focal length becomes longer and therefore, the effective diameters of the lens units are liable to become large, and this is unsuitable for compactness. Further, the lens unit most adjacent to the magnification side has positive refractive power, and this is also unsuitable for securing a sufficient back focus. Moreover, this zoom optical system supposes the use of a light source of a single wavelength, and is not suited for the projection display of a color image.
Also, in the zoom optical system disclosed in Japanese Patent Application Laid-open No. 2002-055279, there is a case where the synthesized refractive power of adjacent lens units becomes negative, and the refractive power is small. Accordingly, the focal length is as great as at least 190 mm. This is because this zoom optical system is an optical system suited for an exposing apparatus, and this zoom optical system is unsuitable for the optical system of a projector or the like of which the downsizing and wider angle are desired. Also, this zoom optical system, like the zoom optical system disclosed in Japanese Patent Application Laid-open No. 2002-207167, supposes the use of a light source of a single wavelength and therefore, is not suited for the projection display of a color image.


A connector module for communication includes a main body, a slider, a holder, a protrusion and an elastic member. The slider is telescoped into the protrusion and connected with the holder. The holder slides the slider, enabling the protrusion to move in and out from the main body, so that the main body can be detachably assembled with a casing.

The invention relates to a connector module, and in particular, to a connector module specified under the X2 multi source agreement (X2 MSA).
In connector systems, especially for fiber-optic communication network, an optical transceiver module functions as a connecting interface between the host and the transmission line. In practice, it is desired that the optical transceiver module can utilize minimal space to attain a maximum connection number. Additionally, the optical transceiver module should be able to provide hot swapping, i.e. exchanging or replacing modules without shutting down the host. To meet functional requirements and establish the uniform specifications of modules, a consortium of top-tier optical component suppliers announced X2, a multi source agreement (MSA) for smaller-form-factor 10 Gbit/s pluggable transceivers.
According to the MSA, modules should have the same physical sizes; therefore, all suppliers are devoted to simplifying the inner structure and mechanism of the module and minimizing manufacturing process to achieve easy fabrication and lower costs.


Systems and methods are disclosed herein to provide improved techniques for loading of configuration memory cells in integrated circuits, such as programmable logic devices. For example, in accordance with an embodiment of the present invention, a programmable logic device includes a non-volatile memory adapted to store a first bit, a second bit, and a plurality of configuration data; a plurality of configuration memory cells; and control logic adapted to determine based on values of the first and second bits whether to load the configuration data from the non-volatile memory into the configuration memory cells.

Various programmable logic devices (PLDs), such as field programmable gate arrays (FPGAs) or complex programmable logic devices (CPLDs), include configuration memory that may be loaded with configuration data for specific applications. In certain PLDs, the configuration memory may be volatile in nature. As such, the configuration data may be loaded into the configuration memory from another non-volatile memory, such as a flash memory, in response to appropriate instructions or when the PLD is powered up.
It is desirable that the configuration data loaded into the configuration memory corresponds to a valid data pattern that facilitates meaningful operation of the PLD. If invalid configuration data is accidentally loaded into the configuration memory, contention errors may cause the PLD to operate improperly or suffer damage.
One approach to determining the validity of configuration data involves the use of a single validation bit in the non-volatile memory. In this approach, as part of an erase process, all bits of the non-volatile memory may be pre-programmed with a particular logic state corresponding, for example, to a logical high state. The non-volatile memory is then erased (corresponding, for example, to a logical low state) and additional conventional operations associated with the erasure of non-volatile memories may be performed. Subsequently, the non-volatile memory is loaded with configuration data. Following the loading, the validation bit may be programmed to a logical high state again to indicate a successful loading of the configuration data.
Unfortunately, if a power failure occurs during the pre-programming operation, the validation bit may be erroneously left at the logical high state which falsely indicates that a valid configuration data pattern has been loaded into the non-volatile memory. As a result, an invalid configuration data pattern may be inadvertently loaded into the volatile configuration memory of the PLD when power is restored.
In certain applications, users may wish to ensure that valid configuration data is provided in non-volatile memory of the PLD, but may also wish to control whether the configuration data is loaded into configuration memory when the PLD is powered up. Unfortunately, where a single validation bit is used as in the prior approach identified above, configuration data may be automatically loaded into configuration memory whenever the PLD is powered on and the validation bit has been programmed to a logical high state. As a result, users may be unable to prevent the loading of configuration data into configuration memory when desired for particular applications.
Accordingly, there is a need for an improved approach to the loading of configuration data that reduces the risk of inadvertent loading of invalid or corrupted configuration data into configuration memory, and that provides users with additional control over the loading.

Selective loading of configuration data into configuration memory cells


The operating range of joint additive and convolutive compensating method is extended by enhanced channel estimation procedure that adds SNR-dependent inertia and SNR-dependent limit on the channel estimate.

A speech recognizer trained on clean speech data and operating in different environments has lower performance due to at least the two distortion sources of background noise and microphone or channel changes. Handling simultaneously the two is critical to the performance of the recognizer.
There are many front-end solutions that have been developed and have shown to give promising results for connected digit recognition applications in very noisy environments. See references 2 and 3. For instance, there are methods such as ETSI advanced DSR front-end that handles both channel distortion and background noise. See D. Macho, L. Mauuary, B. Noe, Y. M. Cheng, D. Ealey, D. Jouvet, H. Kelleher, D. Pearce, and F. Saadoun, "Evaluation of a Noise-robust DSR front-end on AURORA databases," Proc. Int. Conf. on Spoken Language Processing, Colorado, UAS, September 2002, pp 17–20. These techniques do not require any noise training data. To be effective in noise reduction, they typically require an accurate instantaneous estimate of the noise spectrum.
Alternate solutions consist, instead, of modifying the back-end of the recognizer to compensate for the mismatch between the training and recognition environments. More specifically, in the acoustic model space, a convolutive (e.g. channel) component and an additive (e.g. background noise) component can be introduced to model the two distortion sources. See the following references: M. Afifty, Y. Gong, and J. P. Haton, "A general joint additive and convolutive bias compensation approach applied to noisy Lombard speech recognition," IEEE Trans. On Speech and Audio Processing, vol. 6, no. 6, pp 524–538, November 1998; J. L. Gauvain, L. Lamel, M. Adda-Decker, and D. Matrouf, "Developments in continuous speech dictation using the ARPA NAB news task, " in Proc. of IEEE Int. Conf. on Acoustics, Speech and Signal Processing, Detroit, 1996, pp 73–76; Y. Minami and S. Furui, "A maximum likelihood procedure for a universal adaptation method based on HMM composition," in Proc. of IEEE Int. Conf. on Acoustics, Speech and Signal Processing, Detroit, 1995, pp 129–132; M. J. F. Gales, Model-Based Techniques for Noise Robust Speech Recognition, Ph.D. thesis, Cambridge University, U.K., 1995; Y. Gong, "A Robust continuous speech recognition system for mobile information devices (invited paper)," in Proc. Of International Workshop on Hands-Free Speech Communication, Kyoto, Japan, April 2001; and Y. Gong, "Model-space compensation of microphone and noise for speaker-independent speech recognition," in Proc. of IEEE Int. Conf. on Acoustics, Speech, and Signal Processing, Hong Kong, April 2003. The effect of the two distortions introduces in the log spectral domain non-linear parameter changes, which can be approximated by linear equations. See S. Sagayama, Y. Yamaguchi, and S. Takahashi, "Jacobian adaptation of noisy speech models," in Proc. of IEEE Automatic Speech Recognition Workshop, Santa Barbara, Calif., USA, December 1997, pp 396–403, IEEE Signal Processing Society and N. S. Kim, "Statistical linear approximation for environmental compensation, IEEE Signal Processing Letters, vol. 5, no. 1, pp 8–11, January 1998.
It is desirable to provide a more robust utilization of a framework recently developed by Texas Instruments Incorporated known as JAC (Joint compensation of Additive and Convolutive distortions). This is described in patent application Ser. No. 10/251,734; filed Sep. 20, 2002 of Yifan Gong entitled "Method of Speech Recognition Resistant to Convolutive Distortion and Additive Distortion." JAC handles simultaneously both background noise and channel distortions for speaker independent speech recognition. Joint additive acoustic noise and convolutive channel noise compensating algorithms for improved speech recognition in noise are not able to operate at very low signal to noise ratios (SNR). This application is incorporated herein by reference. The reason lies in the fact that when the compensation mechanism of the recognizer is suddenly exposed to a new type of channel noise or to a very low SNR signal, inaccurate channel estimates or insufficient background noise compensation will degrade the quality of the subsequent channel estimate, which in turn will degrade recognition accuracy and channel estimate of the next sentence exposed to the recognizer.

Method to extend operating range of joint additive and convolutive compensating algorithms


A hybrid SOFC/gas turbine electric generating system comprising an SOFC stack, a hydrocarbon reformer, a first anode tailgas hydrogen-rich combustor to drive a first gas turbine stage, and a second stoichiometric combustor to drive a second gas turbine stage to drive a generator. Anode tailgas is also recycled into the reformer for substantially endothermic reforming of hydrocarbon fuel. Oxidant is provided as pure oxygen—which may be stored as liquid oxygen. All nitrogen may be excluded. Cathode exhaust is passed to the first combustor, to the second combustor, and is recycled into the cathodes. The turbine exhaust is passed through successive heat exchangers cooled by liquid oxygen being vaporized, precipitating water and solid CO2. The system is operated at about 800 kPa (about 8 atmospheres), thereby increasing the power output of the stack. The system may be operated with no gaseous exhaust or with by-products of water and CO2.

Solid oxide fuel cell (SOFC) systems are well known. A typical prior art SOFC system uses reformed hydrocarbon fuels and air to generate electricity, syngas, and heat. Syngas is defined as the tail gas from the stack anodes, which is relatively rich in hydrogen (H2) and water.
The only component in air that is useful for the electrochemical reaction within the fuel cell is oxygen, which comprises about 20%. The majority component in air is nitrogen (N2) which comprises about 80%. Nitrogen represents a large volume of inert gas which must be compressed and heated along with the oxygen when air is provided to the reformer for reforming the hydrocarbon fuel and to the SOFC stack for electrochemical reaction with hydrogen.
It is further known to couple an SOFC system to a gas turbine system in a hybrid configuration for generating electricity wherein the effluents from the SOFC are mixed and expanded in a gas turbine to produce additional electricity. Such a hybrid system has the potential to be an extremely high efficiency system.
Prior art SOFC stacks typically are air cooled. Excess air, well beyond the requirement for electrochemical operation, is used to remove heat generated in the stack. The volume of nitrogen present in an air-supplied SOFC system is useful in helping to cool the stack and manage stack temperatures.
Operating a system with high rates of anode tail gas recycled into either the reformer or into the anode inlet allows lower cathode air flow rates and flatter stack temperature profiles, thus improving power density and system efficiency. Such operation also serves to raise the temperature of the stack post-combustor, thus allowing better matching with the inlet temperature requirements of a gas turbine.
Prior art hybrid SOFC/gas turbine systems are not well-suited to some specialized applications. For example, in marine uses such as in manned or unmanned undersea vehicles, aircraft, or in space craft, the presence of NOx in the exhaust is especially undesirable, as may be a gaseous exhaust of any kind in, for example, clandestine undersea operations. Further, for such vehicles, the potential length of submersion or space travel may be governed by the volumes of fuel and oxidant that can be carried.
What is needed in the art is a hybrid SOFC/gas turbine system that produces no nitrogen or oxides of nitrogen in the exhaust.
What is further needed in the art is a hybrid SOFC/gas turbine system that produces a highly concentrated stream of carbon dioxide (CO2).
What is still further needed in the art is a hybrid SOFC/gas turbine system that produces no gaseous exhaust.
What is still further needed in the art is a fuel cell electric generating system that performs for an extended length of operation on a single fueling of oxidant and hydrocarbon fuel.
It is a principal object of the present invention to generate electricity in a fuel cell system without producing nitrogen or oxides of nitrogen in the exhaust.
It is a further object of the invention to provide such a system wherein the exhaust comprises only water and CO2.
It is a still further object of the invention to provide such a system that performs for an extended length of operation on a single fueling of oxidant and hydrocarbon fuel.

Hybrid solid oxide fuel cell and gas turbine electric generating system using liquid oxygen


A rolling bearing includes: an inner race; an outer race; rolling elements provided between the inner and outer races; and a seal member provided between end portions of the inner and outer races, which includes a core metal and a rubber seal including a recess and a projection at an outer surface thereof.

This invention relates to a rolling bearing, and more particularly to a rolling bearing suitably used for, for example, a pulley for a compressor for car air-conditioners, and for an idler pulley.
A four-point contact ball bearing having an inner race, an outer race, balls provided between central portions of the two races, and seal members provided between end portions of the two races has heretofore been known (JP-A-2002-130290) as a rolling bearing used for a pulley for a compressor for car air-conditioners.
In a rolling bearing used for a pulley for a compressor for a car air-conditioner, the heat from a compressor body is transmitted the bearing, so that the temperature in an inner portion of the rolling bearing is liable to become high. When a four-point contact ball bearing is used for the same purpose, a slip on the contact portions of the races and balls occurs greatly, and this therefore makes a source of generation of heat. Moreover, when a pulley formed out of a resin is used, the heat in an inner portion of the bearing comes to rarely escape as compared with a case where a pulley formed out of a metal of a high thermal conductivity is used. Therefore, when a four-point ball bearing is used for a compressor in which a resin pulley is used, the temperature of an inner portion of the rolling bearing becomes high. This possibly causes the rubber seals in the rolling bearing to be easily deteriorated, and the seizure-free lifetime of the rolling bearing to be shortened due to the imperfect lubrication of the rolling bearing with grease.
In order to solve the above problems, a rolling bearing disclosed in JP-A-9-210071 in which shielding plates made of metal are used as seal members, and rubber seals are omitted may be used. However, sealing conducted by the metallic shielding plates is a non-contact seal, which is not appropriate for the use of the bearing at high speed.


A system or computer usable program product for redacting QA system answer information based on user access to content including analyzing a corpus by natural language processing techniques, wherein the corpora includes non-sensitive and sensitive content, and storing the analyzed corpora in memory; receiving a user question to be answered by utilizing the analyzed corpora; utilizing a processor to determine a set of answer information by processing using the corpora; determining a user access right to sensitive content; and redacting an answer information item from the set of answer information if sensitive content to which the user does not have access was used to determine the answer information item.

1. Technical Field
The present invention relates generally to managing user access to query results, and in particular, to a computer implemented method for selectively redacting query results based on data source restrictions and user privileges.
2. Description of Related Art
With the use and improvement of natural language processing (NLP), computers are becoming better at processing human originated speech and writings. Human language is very complex and includes a variety of ambiguities and uncertainties that are difficult for computers to manage. Hand written rules have been developed to assist in this process, but were insufficient to solve the complexity of problems encountered in analyzing human language. Subsequently, statistical models were developed and more recently statistical machine learning techniques have been utilized to improve NPL substantially.
NLP has been utilized in a variety of applications including spelling and grammar correction in documents being typed, summarizing text or documents, language translation, and for providing answers to user queries. In many of these applications, NLP is utilized in multiple capacities. For example, in providing answers to use queries, a computer may have utilized NLP for analyzing a multitude of documents (corpora) in electronic form to develop a content database with indices to the underlying documents. The corpora can include human generated documents, machine translated documents, web pages, etc. that were produced or captured in electronic form. This content database can then be utilized to rapidly search and access the underlying corpora, thereby quickly providing an answer to a user in response to a user query that is also analyzed with NLP.

INTERNATIONAL BUSINESS MACHINES CORPORATION


A biaxially textured article includes a rolled and annealed, biaxially textured substrate of a metal having a face-centered cubic, body-centered cubic, or hexagonal close-packed crystalline structure; and an epitaxial superconductor or other device epitaxially deposited thereon.

Current materials research aimed at fabricating high-temperature superconducting ceramics in conductor configurations for bulk, practical applications, is largely focused on powder-in-tube methods. Such methods have proved quite successful for the Bi--(Pb)--Sr--Ca--Cu--O (BSCCO) family of superconductors due to their unique mica-like mechanical deformation characteristics. In high magnetic fields, this family of superconductors is generally limited to applications below 30K. In the Re--Ba--Cu--O (ReBCO, Re denotes a rare earth element), Tl--(Pb,Bi)--Sr--(Ba)--Ca--Cu--O and Hg--(Pb)--Sr--(Ba)--Ca--Cu--O families of superconductors, some of the compounds have much higher intrinsic limits and can be used at higher temperatures. FIG. 1 shows a comparison of optimized properties of various superconductors.
It has been demonstrated that these superconductors possess high critical current densities (Jc) at high temperatures when fabricated as single crystals or in essentially single-crystal form as epitaxial films on single crystal substrates such as SrTiO.sub.3 and LaAlO.sub.3. These superconductors have so far proven intractable to conventional ceramics and materials processing techniques to form long lengths of conductor with J.sub.c comparable to epitaxial films. This is primarily because of the "weak-link" effect.
It has been demonstrated that in ReBCO, biaxial texture is necessary to obtain high transport critical current densities. High J.sub.c 's have been reported in polycrystalline ReBCO in thin films deposited on special substrates on which a biaxially textured non-superconducting oxide buffer layer is first deposited using ion-beam assisted deposition (IBAD) techniques. IBAD is a slow, expensive process, and difficult to scale up for production of lengths adequate for many applications.
High J.sub.c 's have also been reported in polycrystalline ReBCO melt-processed bulk material which contains primarily small angle grain boundaries. Melt processing is also considered too slow for production of practical lengths.
Thin-film materials having perovskite-like structures are important in superconductivity, ferroelectrics, and electro-optics. Many applications using these materials require, or would be significantly improved by, single crystal, c-axis oriented perovskite-like films grown on single-crystal or highly aligned metal or metal-coated substrates.
For instance, Y--Ba.sub.2 --Cu.sub.3 --O.sub.x (YBCO) is an important superconducting material for the development of superconducting current leads, transmission lines, motor and magnetic windings, and other electrical conductor applications. When cooled below their transition temperature, superconducting materials have no electrical resistance and carry electrical current without heating up. One technique for fabricating a superconducting wire or tape is to deposit a YBCO film on a metallic substrate. Superconducting YBCO has been deposited on polycrystalline metals in which the YBCO is c-axis oriented, but not aligned in-plane. To carry high electrical currents and remain superconducting, however, the YBCO films must be biaxially textured, preferably c-axis oriented, with effectively no large-angle grain boundaries, since such grain boundaries are detrimental to the current-carrying capability of the material. YBCO films deposited on polycrystalline metal substrates do not generally meet this criterion.
The terms "process", "method", and "technique" are used interchangeably herein.
For further information, refer to the following publications:
1. K. Sato, et al., "High-J.sub.c Silver-Sheathed Bi-Based Superconducting Wires", IEEE Transactions on Magnetics, 27 (1991) 1231. PA1 2. K. Heine, et al., "High-Field Critical Current Densities in Bi.sub.2 Sr.sub.2 Ca.sub.1 Cu.sub.2 O.sub.8+x /Ag Wires", Applied Physics Letters, 55 (1991) 2441. PA1 3. R. Flukiger, et al., "High Critical Current Densities in Bi(2223)/Ag tapes", Superconductor Science & Technology 5, (1992) S61. PA1 4. D. Dimos et al., "Orientation Dependence of Grain-Boundary Critical Currents in Y.sub.1 Ba.sub.2 Cu.sub.3 O.sub.7-8 Bicrystals", Physical Review Letters, 61 (1988) 219. PA1 5. D. Dimos et al., "Superconducting Transport Properties of Grain Boundaries in Y.sub.1 Ba.sub.2 Cu.sub.3 O.sub.7 Bicrystals", Physical Review B, 41 (1990) 4038. PA1 6. Y. Iijima, et al., "Structural and Transport Properties of Biaxially Aligned YBa.sub.2 Cu.sub.3 O.sub.7-x Films on Polycrystalline Ni-Based Alloy with Ion-Beam Modified Buffer Layers", Journal of Applied Physics, 74 (1993) 1905. PA1 7. R. P. Reade, et al. "Laser Deposition of biaxially textured Yttria-Stabilized Zirconia Buffer Layers on Polycrystalline Metallic Alloys for High Critical Current Y--Ba--Cu--O Thin Films", Applied Physics Letters, 61 (1992) 2231. PA1 8. D. Dijkkamp et al., "Preparation of Y--Ba--Cu Oxide Superconducting Thin Films Using Pulsed Laser Evaporation from High Tc Bulk Material," Applied Physics Letters, 51, 619 (1987). PA1 9. S. Mahajan et al., "Effects of Target and Template Layer on the Properties of Highly Crystalline Superconducting a-Axis Films of YBa.sub.2 Cu.sub.3 O.sub.7-x by DC-Sputtering," Physica C, 213, 445 (1993). PA1 10. A Inam et al., "A-axis Oriented Epitaxial YBa.sub.2 Cu.sub.3 O.sub.7-x --PrBa.sub.2 Cu.sub.3 O.sub.7-x Heterostructures," Applied Physics Letters, 57, 2484 (1990). PA1 11. R. E. Russo et al., "Metal Buffer Layers and Y--Ba--Cu--O Thin Films on Pt and Stainless Steel Using Pulsed Laser Deposition," Journal of Applied Physics, 68, 1354 (1990). PA1 12. E. Narumi et al., "Superconducting YBa.sub.2 Cu.sub.3 O.sub.6.8 Films on Metallic Substrates Using In Situ Laser Deposition," Applied Physics Letters, 56, 2684 (1990). PA1 13. R. P. Reade et al., "Laser Deposition of Biaxially Textured Yttria-Stabilized Zirconia Buffer Layers on Polycrystalline Metallic Alloys for High Critical Current Y--Ba--Cu--O Thin Films," Applied Physics Letters, 61, 2231 (1992). PA1 14. J. D. Budai et al., "In-Plane Epitaxial Alignment of YBa.sub.2 Cu.sub.3 O.sub.7-x Films Grown on Silver Crystals and Buffer Layers,"0 Applied Physics Letters, 62, 1836 (1993). PA1 15. T. J. Doi et al., "A New Type of Superconducting Wire; Biaxially Oriented Tl.sub.1 (Ba.sub.0.8 Sr.sub.0.2).sub.2 Ca.sub.2 Cu.sub.3 O.sub.9 on {100}<100> Textured Silver Tape," Proceeding of 7th International Symposium on Superconductivity, Fukuoka, Japan, Nov. 8-11, 1994. PA1 16. D. Forbes, Executive Editor, "Hitachi Reports 1-meter Tl-1223 Tape Made by Spray Pyrolysis", Superconductor Week, Vol. 9, No. 8, Mar. 6, 1995. PA1 17. Recrystallization Grain Growth and Textures, Papers presented at a Seminar of the American Society for Metals, Oct. 16 and 17, 1965, American Society for Metals, Metals Park, Ohio.

Structures having enhanced biaxial texture and method of fabricating same


A lens holder includes a third group frame that serves as a holding member which holds lenses, a guide shaft that supports the third group frame when the third group frame is moved along the optical axis of the lenses, a rear barrel part perpendicularly to which the guide shaft is locked, a first bearing member that is molded as an integral part of the rear barrel part in order to bear the end of the guide shaft distal to the rear barrel part, and a guide shaft presser that when the first bearing member bears the end of the guide shaft distal to the base, bears the end of the guide shaft proximal to the rear barrel part.

In recent years, imaging apparatuses including a digital still camera and a digital video camera have been designed more and more compactly in pursuit of improved portability and better user-friendliness. Accordingly, a housing of an optical system or a lens barrel employed in the imaging apparatus has been designed more and more compactly. There is still an increasing demand for higher image quality and a larger number of pixels. Even if lenses that are optical elements are made larger in size, a driving mechanism is downsized in order to realize a compact housing of an optical system.
Moreover, a so-called collapsible lens barrel employed in an imaging apparatus such as a digital still camera or a digital video camera has been requested to become more compact and thin from the viewpoint of portability and accompanying usefulness. In particular, as for the digital still camera, articles resulting from the quest for further portability and accompanying usefulness such as articles capable of being put into a chest pocket of a shirt or a pocket of jeans are winning popularity nowadays. There is therefore a great demand for a thin housing of an optical system.
The so-called collapsible lens barrel has been disclosed in Japanese Unexamined Patent Publication No. 2002-296480, and the lens driving mechanism has been disclosed in Japanese Unexamined Patent Publication No. 2002-287002. In general, a guide shaft must be highly precisely positioned and locked in order to cramp movable lenses, which are incorporated in the collapsible lens barrel or a collapsible camera, so that the lenses can be moved in optical-axis directions, while highly precisely aligning the movable lenses with one another.

Lens holding device, lens-barrel, and imaging device


A double-dispenser system for dispensing medicinal liquids has two jet-trigger pumps housed in an outer casing having at least one front opening and one rear opening. Each jet-trigger pump is provided with a dosing mechanism for dispensing a predetermined dose of medicinal liquid. Dispensation from the two pumps may be triggered simultaneously by a trigger device common to the two pumps and accessible from the outside of the casing. The pumps incorporated in the double-dispenser system may be of the type having a pump body and a piston housed in an elastic bottle. For each pump, relative movements between the piston and the pump body causes changes in the relative-displacement between the piston and the pump body such that medicinal liquid is initially loaded into a medicine-holding cavity within the pump and subsequently dispensed.

Topical instillation has been the most common method of administration for ophthalmic medications since ocular treatments have existed. That is why it would be expected to be simple, practical and efficient.
Even though there is normally a certain number of patients who can administer their medications themselves, studies on the observance of medicinal directions show that a large number of them do not succeed in doing this. The necessity in ambulatory medicine of relying on the patient to carry out correct treatment is a factor in the non-compliance with doctors' directions and more particularly when the treatment is as difficult as in ophthalmology.
The impossibility of a patient positioning the end of the normal droppers without a mirror, or without corrective lenses when the latter are necessary for looking at oneself in a mirror, is very dangerous. There is a high risk of damaging the cornea together with a risk of contamination of the active constituent of the medication if the end of the dropper comes into contact with the conjunctiva as in the majority of cases.
Furthermore, when a drop is administered to the eye successfully despite the above difficulties, a significant loss of medication occurs by overflowing onto the face and by draining into the naso-lachrymal canal.
The distribution of the active substance in the general circulation essentially occurs by the intermediary of the naso-lachrymal canal. Its presence in the systemic circulation contributes to the appearance of serious general secondary effects following a simple ocular instillation and this has generated considerable interest in the design of various systems for the administration of active constituents which could minimize the risk of systemic toxicity.
If the liquid is trapped in the folds of the conjunctiva is included, the normal volume of tears in the eye is about 10 ml. A total volume of liquid of about 20 ml can be retained for a short time, if the eyelids are not closed again after the administration of the topical medication. When a single drop of medication is applied to the eye, normally having a volume of 30 to 60 ml, the major portion of the administered drop runs over the cheeks whilst the naso-lachrymal drainage system rapidly drains off the excess volume.
Thus, increasing the size of the drops does not increase the bioavailability. According to some authors, only 5% of the total quantity of the active ingredients in fact reach the aqueous humour.
On the contrary, the large size of the drops causes an exacerbation of corneal sensitivity which itself causes two synergic defence reflexes: the blinking of the eyes and lachrymation, the combination of these two resulting in the elimination of the major portion of the ophthalmic drop.
However, systemic absorption is proportional to the size of the drop, given that the subsequent drainage through the naso-lachrymal canal usually leads to the active constituent being absorbed into the plasma through the nasal mucosa or even to being swallowed.
When, in ophthalmology, active constituents are used which have potential systemic secondary effects, such as beta-blockers, it is important to try to limit the size of the drops in order to minimize the risk of secondary effects. For the purpose of reducing systemic absorption, it has been proposed for example to compress the nasal end of the lower eyelid for five minutes after the instillation in order to cause the occlusion of the lachrymal point. That is why it would be desirable to have a device designed to prevent systemic re-absorptions, that is to say to deliver a dose of the active product or products whose volume does not exceed the 25 ml maximum volume available in the conjunctival space.
Certain pathologies require, in a good number of cases, the combination of two active constituents. It would be desirable for the said device to be able to deliver, for example, two separate drops of 12.5 ml of two different liquids. A good number of active constituents used in ophthalmology are very difficult to combine into a single formulation. This is the case for example when it is desired to associate one hydrophilic active compound with a lipophilic active compound or two compounds with a different pH. Such a combination cannot be achieved in the same bottle without a major change in at least one formulation, leading to a significant reduction in its penetration or in its action. Furthermore, to administer two separate topical solutions results in excessive volumes and even more side effects while less active ingredient of the first drop is left as a result of the wash out by the second drop. This is especially true in ocular applications as well as for most of topical application.
This is the case, in ocular instillation for example, for a combination of dorzolamide (Trusopt) and epinephrine. The respective volumes of each of these two components administered is normally 30 ml for the former and 40 to 60 ml for the latter, which results in a minimum total volume of about 70 ml. Now, as mentioned above, the capacity of the eye is a maximum of 20 to 25 ml. That is why a combined formula of this association has been developed by the manufacturer, at the cost of major difficulties, an enormous budget and more than twelve years of development.
Furthermore, it would be desirable for the administration of the medication to take place in a part of the eye which is not very sensitive in order to avoid the reactions mentioned above. Such a low-sensitivity zone is the lower conjunctival cul-de-sac.
It would therefore be desirable to have an instillation device capable of simultaneously dispensing two separate active constituents and complying with the objectives and constraints defined above.
Such a device should preferably allow a patient to instill easily and concomitantly two separate drops of a medication by self-administration, in any environment whatsoever, whether this be at home, at work or elsewhere, without having to tilt the head backwards.
This device should be reliable and should eliminate the present risks of damaging the eye and of contaminating the contents.
Furthermore, the size of the drops thus administered should be small, so that the sum of the two drops administered does not exceed the maximum capacity of the eye, in order to control the dose of medication actually administered and to minimize the risk of systemic absorption with the potential toxicity which accompanies this.
In fields other than ophthalmology, certain pathologies also require, in a large number of cases, the association of two active ingredients. A large number of active ingredients, for example in Otorhinolaryngology, Pneumatology, Dermatology, Gynaecology, are very difficult to combine in a single formulation. This is the case for example, as mentioned above, when it is desired to associate a hydrophilic active compound with a lipophilic compound in a liquid phase when the two active compounds whose penetration and activity pH figures differ from one another. Such a combination cannot be achieved in the same bottle without a significant change in at least one formulation, which leads to a significant reduction in its penetration or its efficacy.


Dot mark decoding circuitry sets an initial value of a relative position of each of dot marks with respect to a corresponding lattice point; and then sequentially executes, in repetition, a calculation process of calculating a projective transformation matrix based on a position of each dot mark in a pixel coordinate system and a position obtained by adding the relative position to the position of a corresponding lattice point; a transformation process of transforming the position of each dot mark from the position in the pixel coordinate system to a position in a L coordinate system using the projective transformation matrix; a generation process of generating the relative position information based on the post-transformation position of each dot mark and the position of the corresponding lattice point; and an update process of updating the relative position in accordance with the relative position information.

1. Technical Field
The present disclosure relates to an electronic pen and a handwriting input system using the same.
2. Description of the Related Art
Japanese Laid-Open Patent Publication No. 2007-226577 discloses a technology by which for writing a letter or the like on a sheet of paper on which a great number of dot marks obtained by coding positions are located by printing or the like, information provided on the sheet of paper is made electronic data by use of an electronic pen and the information made the electronic data is sent to a server or a terminal. Japanese Laid-Open Patent Publication No. 2012-128563 discloses a handwriting input system by which a great number of dot marks obtained by coding positions are located on a digital display or the like and handwriting input is performed on the digital display by use of an electronic pen.

Panasonic Intellectual Property Management Co., Ltd.


A metal cabinet includes a plurality of horizontal shelf members and a plurality of vertical dividers. Each shelf member includes a plurality of slits extending between edges of the shelf member. Each vertical divider includes a plurality of slits extending between edges of the divider. One shelf member slit receives a divider and one divider slit receives a horizontal shelf member.

The present invention relates generally to units for storage. More particularly, the invention relates to an improved compartment bin that is easily and quickly assembled.
Metal compartment bins and cabinets are some of the most versatile pieces of furniture available. The cabinets can be hung in work areas such as metal or woodworking shops, garages, as well as many other places. Cabinets and compartment bins can also provide storage in vehicles such as trucks and vans. Metal cabinets also provide versatility in what they store. For example, metal cabinets and compartment bins have been used to store threaded rod, wire, brake line, welding rods, as well as more common items such as tools and fasteners.
Bins or cabinets having a plurality of compartments are usually assembled with numerous amounts of attachments between the components. For example, shelves can be mechanically fastened or welded to dividers. As the number of shelves and dividers increase the manufacturing process becomes both more costly and timely.
Also, conventional storage cabinets are typically first assembled at the manufacturing location and then shipped to the end buyer or consumer. Any reduction in time of assembly of the cabinet results in a lower cost for the assembled cabinet. Accordingly, it is desirable to provide a storage cabinet that is quicker and more economical to assemble.


A portable electronics distress detection system includes at least one strain gage and an alarm circuit. The strain gage is mountable to an element of the portable electronic device. The alarm circuit includes a Wheatstone bridge associated with each strain gage, with each strain gage providing a resistance input to an arm of the associated Wheatstone bridge. When a mechanical stress is imposed on the portable electronic device, the strain gage changes the resistance input to the arm of the associated Wheatstone bridge, producing a nonzero voltage output from the Wheatstone bridge. The alarm circuit activates the portable electronic device user interface if the Wheatstone bridge voltage output exceeds a predetermined set point.

This disclosure relates to portable electronic devices, such as MP3 players, cell phones, PDA's, digital cameras, etc.
Many people carry one or more portable electronic device whenever they leave their house or workplace. Portable electronic devices are designed to be small and lightweight to facilitate storage on or about a person, and are therefore constructed with thin metal and/or plastic housings. When not in use, the portable electronic devices are often stored in a pocketbook, backpack, briefcase, etc., subjecting the devices to damage due to external stresses induced on the housing by other stored objects. Portable electronic devices may also be overflexed during use, thereby causing damage.

Portable electronic device distress detection system


A method of joining an amorphous alloy material to a heterogeneous material and a composite formed by the same are provided. The method comprises steps of: placing a pre-formed piece made of one of the amorphous alloy material and the heterogeneous material into a mold; heating the other of the amorphous alloy material and the heterogeneous material to a predetermined temperature, and casting the other of the amorphous alloy material and the heterogeneous material into the mold to form a transition connection part joining the amorphous alloy material to the heterogeneous material and having a fusion welded structure, a microstructure reinforcing connection structure and a composite connection structure; and cooling the amorphous alloy material and the heterogeneous material at a rate higher than a critical cooling rate of the amorphous alloy material to obtain a composite formed by joining the amorphous alloy material to the heterogeneous material by the transition connection part.

The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
Currently, there are more and more needs for products with precision and durability, high reliability and high strength, however, conventional materials and conventional forming and joining technologies may hardly meet design requirements for products. For example, although a magnesium alloy has light weight and may be precisely formed, the magnesium alloy may be poor in strength and easy to crack, and may not be corrosion resistant. Although an aluminum alloy may be precisely formed and may have corrosion resistance and colorful decoration property, however, the aluminum alloy may be low in hardness and may not be wear resistant. Although a zinc alloy may be low in price and easy to form, the zinc alloy may be low in strength, and may not be corrosion resistant. Although a stainless steel may have high strength and high corrosion resistance, the stainless steel may be difficult to precisely form. Even if the stainless steel may be precisely machined, the machining cost is very high, so the stainless steel may be difficult to popularize.
Due to the unordered and uniquely arranged structure of atoms constituting an alloy, an amorphous alloy material, also referred to as metallic glass, may have excellent physical and chemical properties different from those of common crystalline metal materials, for example, high yield strength, high hardness, superelasticity (i.e., high elastic limit), high wear resistance, and high corrosion resistance, so may have broad application prospects.
An amorphous alloy has been first reported in 1960s. Because the critical size (i.e., the largest size to form an amorphous alloy) of the initial amorphous alloy only may reach micron scale, the initial amorphous alloy may be difficult to practically use. In recent years, gradual increase of the critical size of the amorphous alloy makes possible industrial application of the amorphous alloy.
The amorphous alloy has excellent casting performance. For example, the amorphous alloy has low melting temperature like a magnesium alloy, an aluminum alloy, a zinc alloy or a copper alloy, for example, the melting temperature of a rare-earth-based amorphous alloy may be as low as about 300° C. Because the amorphous alloy retains the structural feature of a molten state without phase change, the shrinkage rate of the amorphous alloy may be lower than that of a conventional metal and a plastic. Like a plastic, the amorphous alloy not only has a melting temperature and a glass transition temperature, but also has a large supercooled liquid phase region, so the amorphous alloy may have high flowability and good replicating of the shape and surface of a cast. Meanwhile, without performance difference caused by composition segregation and grain coarsening, the amorphous alloy in a casting state may have excellent mechanical property. The above advantages enable the amorphous alloy to have broad application prospects. For example, the use of an amorphous alloy material to manufacture a frame for an electronic device may solve problems of scratching, destruction under force, and other defects caused by insufficient hardness and strength in a frame made of a conventional metal material. The amorphous alloy material may also be used for manufacturing a structural member with very complex structure and high strength, which may solve large-cutting-amount machining problems created when a steel is used for manufacturing a precise structural member with complex structure and high strength. Meanwhile, the amorphous alloy material may be used for forming a precise micro-gear, which may solve problems of forming difficulty and poor wear resistance of the micro-gear.
However, due to some inherent characteristics of the amorphous alloy, the application of the amorphous alloy material is largely affected. For example, because the hardness of the amorphous alloy is high, when machining, punching and drilling need to be performed on an amorphous alloy article, the process difficulty may be increased, and the life of a cutting tool may be significantly shortened, thus enhancing the production cost. In addition, for an article with very complex structure and a wall thickness not larger than about 0.3 mm, the amorphous alloy article may be difficult to form, which may enhance the production cost to a large extent or even cause the production of the amorphous alloy article not to be carried out. Meanwhile, because the plastic deformation of the amorphous alloy is carried out by forming and extending a low-viscosity region of a shear band, the amorphous alloy generally exhibits very low plastic deformation and appears as a brittle material, which may largely restrict the application of the amorphous alloy in a device for which high safety is required, for example, the application of the amorphous alloy in an article for which drop performance or impact performance are specially required. Meanwhile, the use of various amorphous alloy systems, especially amorphous alloy materials with low amorphous formation ability and low cost, may be largely restricted. In addition, currently, an amorphous alloy is generally constituted by a noble metal, which may be high in material cost; and when the structure of an article is being designed, excellent performance of the amorphous alloy is not required for all the structures of articles. Therefore, how to realize low-cost application of a high-cost material is one difficult problem which needs to be solved.
U.S. Pat. Nos. 5,482,580; 6,818,078 and 6,771,490 disclose methods of joining an amorphous alloy material to other materials. However, in the amorphous alloy composite articles manufactured by these conventional methods, the bonding strength between the amorphous alloy material and other materials is low; the impact resistance of the amorphous alloy composite articles is low; and in the methods disclosed in the above U.S. Patents, it is required that the melting temperature of a pre-formed piece is higher than that of a material to be joined to the pre-formed piece, or the elastic limit of the amorphous alloy material is larger than about 1.5%. Therefore, the use of the amorphous alloy to be joined to other materials may be largely restricted.
Meanwhile, in terms of joining technique, buckling, nut, welding, bonding and other conventional techniques are widely used, which may cause low strength and poor reliability or cause high cost due to process complexity. Even if the insert molding technique is used, due to huge difference of heterogenic materials, the bonding strength is still poor.

Composite and preparation method of joining amorphous alloy material to heterogeneous material


A method of drilling an uncompleted lateral wellbore in a subsurface formation includes drilling the uncompleted lateral wellbore with coiled tubing in the subsurface formation. The subsurface formation includes unconsolidated sand and the subsurface formation overlays a water-saturated reservoir. The method may further include introducing particles having an average particle size of from 8 mesh to 140 mesh into the uncompleted lateral wellbore, thereby supporting the uncompleted lateral wellbore and avoiding wellbore collapse and installing a screen in a vertical wellbore fluidly connected to the uncompleted lateral wellbore, wherein the screen has a mesh size of from 325 mesh to 1000 mesh. The subsurface formation may include hydrocarbons and the method may further include producing hydrocarbons from the subsurface formation.

The discovery and extraction of hydrocarbons, such as oil or natural gas, from subsurface formations, may be impeded for a variety of reasons, such as inherently poor permeability or damage to the formation. The production rate of hydrocarbons from a hydrocarbon-producing region of the formation may be reduced compared to the expected production rate. These instances may result because of sand production from the subsurface formation. Sand production is the migration of formation sand from the subsurface formation 200 caused by the flow of reservoir fluids. The production of sand is generally undesirable since it can restrict productivity, erode completion components, impede wellbore access, interfere with the operation of downhole equipment, and present significant disposal difficulties.

Methods of producing hydrocarbons from unconsolidated sand formations


An optimizing apparatus for optimizing a mounter equipped with a line gang pickup head which picks up a plurality of components and mounts them on a board. The apparatus includes a nozzle set determination unit for determining a nozzle set which reduces a mounting time in view of a number of times interchanging pickup nozzles and a total task number necessary for mounting the plural components, a nozzle pattern determination unit for determining an optimal nozzle pattern as well as an arrangement of pickup nozzles (nozzle arrangement) at a nozzle station, based on the nozzle set determined by the nozzle set determination unit, and Z-axis arrangement/mounting order optimization unit for determining an array order of component feeders and a mounting order of components while maintaining the determined nozzle set and nozzle pattern.

1. Field of the Invention
The present invention relates to a method for determining the optimal order in which a mounter is to mount electronic components onto a board, such as a printed circuit board. In particular, the invention relates to the optimization of the order of component mounting for a mounter equipped with a line gang pickup head that picks up a plurality of components and mounts them onto the board.
2. Background of the Related Art
The order in which a mounter mounts electronic components on a board such as a printed circuit board is conventionally optimized to minimize a tact time (i.e., the time taken by mounting). Recently, with diversification of the types of electronic devices, there has been an increase in demand for a multi-functional mounter equipped with a line gang pickup head based on a method referred to as "gang pickup" of picking up a plurality of components and mounting them on a board. Thus, various types of methods for optimization of the order of component mounting for such a mounter are presented (for instance, in Japanese Laid-Open Patent Applications No. 2002-50900 and No. 2002-171097).
The reference mentioned above discloses the method for optimizing an order of component mounting in favor of the mounting of the components performed by a line gang pickup head, namely, prioritizing the maximization of the number of components to be simultaneously picked up by a line gang pickup head per task. Here, one iteration of repeated series of processes where a line gang pickup head picks up, transfers and mounts components, and the group of components handled in such an iteration are both referred to as a "task". The number of tasks required for mounting all the components is minimized owing to such optimization, and therefore, the mounting of the components can be completed with a shorter tact time.
However, the above conventional optimization method takes a lot of processing time to simultaneously determine various conditions for optimization, such as: a Z-axis arrangement which is an array of component feeders to be set on a mounter; an arrangement of nozzles at a nozzle station; a nozzle pattern; and a mounting order (i.e., an order of mounting components in consideration of mounting points on a board). To be more specific, it is a method for searching the conditions optimal on the whole by checking the tact as well as various constraints each time the above conditions for optimization are changed. Therefore, it is necessary to calculate a tact each time the nozzle pattern is changed and thereby it takes time for optimization. Here, a nozzle pattern is a pickup nozzle string in which a type of nozzle for picking up components is determined for each line gang pickup head in each task that is arranged according to the mounting order.
It is also a problem that an optimal solution cannot always be found since a head position and a task and others of the line gang pickup head to be interchanged are determined using random numbers in order to change the conditions for optimization.

Method for optimization of an order of component mounting, apparatus using the same, and mounter

Matsushita Electric Industrial Co., Ltd.