Kazuhiro MOTEGI Shigeyoshi WATANABE
Multi Step Diakoptics (MSD) is a parallel computation method for solving linear equations. It is used for device simulation, being it executed on a parallel computer. The results show the efficiency of the simulation when the number of nodes that are defined by the five point discretization of semiconductor equations, is over 29.
Yoshihiko MUTO Manabu YOSHIKAWA Hiroshi KAYANO
This letter describes transformation of an elliptical emission region of a semiconductor laser into a triple mode pattern of a graded-index optical fiber by a holographic filter. As a result of comparison of experiment with computer simulation, it has been shown that this method is effcient for the above transformation.
Satoshi KOBORI Toshihiko YONEDA
In order to investigate the dynamic balance function, we have studied about the tracking motion in standing posture. We have analyzed the motion using the multiple regression analysis method. It is found that the regression coeffcients indicate the characteristics of the motion.
Chang CHEN Yoshihiro TAKADA Tohru KIKUNO Koji TORII
This letter discusses a relation between reliability and network topology of starred polygon with redundant nodes. Each node of starred polygon is augmented by a spare node, and the degree of survivability is newly defined to evaluate reliability. The main result presents three special topologies of starred polygon with redundant nodes that realize an optimal degree of survivability.
Yoshinari ISHIDO Toshiyuki SHIOZAWA
With the use of the Fourier-Laplace integral, the impulse response for a two-dimensional model of the Cherenkov-type oscillator is obtained. From the numerical analysis of the impulse response, the temporal evolution of the response is found to have two different phases ini which it grows linearly and exponentially with the distance from the origin where an impulsive excitation is applied.
Takuma TANIMOTO Masao YAMANE Shigeo GOTO Yoko UCHIDA
Possibility of high performance P-channel HEMT was investigated. P-channel HEMT structure with an InGaAs strained layer was fabricated and yielded a measured hole mobility of 260-310 cm2/Vs. Numerical simulations based on the experimental results indicate an expected transconductance of 186 mS/mm for the intrinsic part and 82 mS/mm for the extrinsic part (source resistance of 6 Ωmm) for 0.1/µm gate HEMTs.
In this letter we present an efficient root finding technique for a polynomial over GF(2m) when m is even number. The solutions that we have ever known are made to accelerate by our technique.
Shigeki OHBAYASHI Tomohisa WADA Toshihiko HIROSE Kenji ANAMI
This letter describes the fan-out optimization method of the SRAM decoder having line capacitance that minimizes the total delay time. It is shown that the total delay time of the SRAM decoder optimized by this mothod is less than that of the equal fan-out condition.
Kazuo HOGARI Kazuhiro NOGUCHI Takao MATSUMOTO
This letter proposes a new-type of two-dimensional multichannel optical switch employing polarization control techniques. This switch has small-size and low-driving-power characteristics. It is demonstrated by an 88 optical switch.
Junji YAMAUCHI Morihiko IKEGAYA Hisamatsu NAKANO
The beam-propagation method (BPM) is applied to the evaluation of the loss of S-shaped step-index waveguides. It is demonstrated that the BPM enables us to analyze S-shaped bends which have an offset core and a trench section in the cladding at the outer side of the bend.
An errors-and-erasures decoding procedure for t-error-correcting Reed-Solomon codes with designed distance 2t1 is proposed which corrects some patterns of erasures and errors beyond the BCH bound. In the procedure, a decoding algorithm beyond the BCH bound is applied only when the number of erasures is odd.
Shigeru OHO Hisao SONOBE Jun-ichi MAKINO Hiroshi KAJIOKA Tatsuya KUMAGAI
The phase-modulated optical fiber gyroscope signal was analyzed in a time-domain. The rotation rate detected by the gyroscope optics was extracted from the gyroscope signal as time-domain characteristics at the maximum sensitivity.
The relationship between steady arc duration and contact resistance characteristics is studied on Ag-Pd30% alloy contacts. The experimental results show that longer arc duration doesn't necessarily cause higher contact resistance, which is the same result as obtained on silver contact.
Yoshihide ITARASHI Juha KORTELAINEN
A sequence α(a1, , an) is k-sorted if for all 1i, jn, i jk implies aiaj. The number of k-sorted permutations of {1, , n} is denoted by Rk(n). We show that 1.4439n and 1.6933n are average case lower bounds on the numbers of comparisons needed to sort 3-sorted and 4-sorted sequences of length n, respectively. A compact form of a characteristic equation of degree k1 for a lower bound on Rk (n)/Rk(n1) is derived. From this characteristic equation, we also derive a good lower bound on the expected number of comparisons needed to sort k-sorted sequences for each k5.
A new approach for topological routing is proposed by W-graph. We employ a W-graph Gw(V, E, W) for indicating all nets which will be assigned to two-layer, where V is a set of all terminals, E is a set of edges corresponding to two-terminal nets and W is a set of wild components corresponding to multi-terminal nets. Such that the topological routing problem can be considered as: Given a circle H containing V in the sequence corresponding to terminals on the boundary of routing region, then drawing H Gw on a plane with minimum number of created vertices (crossing points on H).
Xue-Hou TAN Tomio HIRATA Yasuyoshi INAGAKI
We examine the problem of reporting all intersecting pairs in a set of c-oriented polygons, each having at most k edges (for some constant k). Polygons are called c-oriented if the edges of all polygons have a constant number of orientations. The problem arises in many applications such as VLSI design rule checking and architecture databases. We present an asymptotically optimal algorithm that reports all pairs in O(n log nt) time and O(n) space, where n is the number of polygons and t the number of intersecting pairs. Since the optimal algorithm may report an intersecting pair more than once (but at most a constant number of times), we also give a further algorithm which reports each pair exactly once but is not space-optimal, namely, requires O(n log n) space.
A necessary and sufficient condition of the ergodicity for a class of Gaussian periodically correlated stochastic processes is given in this paper. Periodically correlated processes are also called cyclostationary processes in wide sense, and these are mainly studied as models of signal processes in the communication theory and as models of time series of practical data of stochastic phenomena in some periodical environment. On the line of Boyles and Gardner's study(10) on cycloergodicity of certain class of nonstationary processes of discrete time parameter, we reformulate such ergodicity of cyclostationary processes in strict sense in continuous time parameter case, and prove a ergodic theorem. Futhermore, we apply it to Gaussian periodically correlated process, and discuss almost sure limiting behavior of a sample periodogram of the process.
Tatsuya TANIAI Iwao SASASE Sinsaku MORI
In this paper, we propose the adaptive cutoff priority for a multiple server finite-capacity buffer system with two kinds of arrival streams to reduce loss probabilities of both kinds of arrivals. The number of reserved" servers for high priority customers is adaptively decreased by using the adaptive cutoff priority, when the number of waiting customers of low priority is increased. We first derive the state probabilities which are the function of both the number of customers in the queue and the number of customers in service, so that it is possible to present general expressions for the loss probability and the average queueing time. Next, the numerical calculation is carried out and it is found that not only the loss probability of each arrival but slso the total loss probability are reduced by using more than two thresholds and selecting the treshold values appropriately. It is shown that the computer simulated results agree with the theoretical results.
To reduce the computational complexity due to the long tap structure of filters used for subband coding, a new structure of filter banks is proposed. Applying the concept of hierarchical coding to the perfect reconstruction condition in a one-dimensional analysis/synthesis system, which is represented as a matrix operation in z-transform domain, our approach realizes perfect reconstruction with short length FIR filters and reduction of the number of filters by half compared with the conventional approaches. Moreover, it is expanded to two-dimensional case, where both a separable structure and a non-separable one are considered.
Wen-Bo ZHAO Boon-Siong WONG Kaoru SEZAKI Yasuhiko YASUDA
Havihg modified and extended the routing algorithm used in our previously proposed Bidirectional Shuffle Ring Network (BSRN), we here provide some adaptive routing algorithms that can relieve the congestion caused by bottlenecks when nonuniform traffic exists. As to preserve the transmission order of cells associated with a message which may otherwise arrive at the destination out of sequence if they are forwarded along different routing paths, two control schemes are also devised. The BSRN proves to be highly reliable and robust since countermeasures against node or link failure can also easily be realized.