Two method to predict targets which a user is about to point with a mouse on the basis of the trajectory of the mouse cursor were proposed. The effects of the interval between targets, the position of targets, the sampling interval and the number of sampling on the pointing time and the prediction accuracy were investigated. In both methods, the distance between targets had little effects on the pointing time. The prediction accuracy was found to be affected by the position of targets. In both prediction methods, the angle between the cursor movement vector and the vector which connects the current cursor position and the center of each target is calculated every st. As for Prediction Method1 that regards the target which correspond to the minimum angle continuously 5 times as the candidate target, the optimal condition of the sampling interval was found to be 0.06 sec or 0.08 sec. Concerning Prediction Method2 that calculates the angle n times and determines the minimum cumulative value as the candidate, the optimal condition of the number of sampling was 8.
Naoshi DOI Akira SHINTANI Yasuhisa HAYASHI Akio OGIHARA Shinobu TAKAMATSU
Recently, some speech recognition methods using fusion of visual and auditory information have been researched. In this paper, a study on the mouth shape image suitable for fusion of visual and auditory information has been described. Features of mouth shape which are extracted from gray level image and binary image are adopted, and speech recognition using linear combination method has been performed. From results of speech recognition, the studies on the mouth shape features which are effective in fusion of visual and auditory information have been performed. And the effectiveness of using two kinds of mouth shape features also has been confirmed.
Kentaro NISHIMORI Nobuyoshi KIKUMA Naoki INAGAKI
This paper addresses approaches to enhancement of performance of the CMA (Constant Modulus Algorithm) adaptive array antenna in multipath environments that characterize the mobile radio communications. The cost function of the CMA reveals that it has an AGC (Automatic Gain Control) procedure of holding the array output voltage at a constant value. Therefore, if the output voltage by the initial weights is different from the object value, then the CMA may suffer from slow convergence because suppression of the multipath waves is delayed by the AGC behavior. Our objective is to improve the convergence characteristics by adopting the differential CMA for the adaptive array algorithm. First, the basic performance of the differential CMA is clarified via computer simulation. Next, the differential CMA is incorporated into the eigen-beamspace system in which the eigenvectors of the correlation matrix of array inputs are used in the BFN (Beam Forming Network). This BFN creates the optimum orthogonal multibeams for radio environments and works helpfully as a preprocessor of the differential CMA. The computer simulation results have demonstrated that the differential CMA with the eigen-beamspace system has much better convergence characteristics than the conventional CMA with the element space system. Furthermore, a modified algorithm is introduced which gives the stable array output voltages after convergence, and it is confirmed that the algorithm can carry out more successful adaptation even if the radio environments are changed abruptly.
The tandem structure of a matched filter (MF) and a maximum likelihood sequence estimator (MLSE) using the Viterbi algorithm (VA) has been considered to be an optimal receiver for digital pulse-amplitude sequences in the presence of intersymbol interference (ISI) and additive white Gaussian noise (AWGN). An adaptive array antenna has the capability of filtering received signals in the spatial domain as well as in the temporal one. In this paper, we propose a receiver structure using an adaptive array antenna, a digital filter and the VA that is spatially and temporally optimal for multi-user detection in a direct sequence code division multiple access (DS/CDMA) environment. This receiver uses a tapped delay line (TDL) array antenna and the VA, which provides a maximum likelihood sequence estimate from the spatially and temporally whitened matched filter (ST-WMF) output. Performance of the proposed receiver is evaluated by theoretical analysis and computer simulations.
This paper proposes and investigates a tap selectable Viterbi equalizer for mobile radio communications. When the multipath channel is modeled by a tapped delay line only, the taps which may seriously affect the data sequence estimation are selected and used to calculate the trellis metric in the Viterbi algorithm. The proposed equalization algorithm can reduce the number of path metric calculations and the number of path selections in the Viterbi algorithm. Moreover, we propose an extended equalizer which has antenna diversity. This equalizer calculates the path metric using the antenna outputs and results of channel estimators. Computer simulation is used to evaluate the BER performance of the proposed equalizer in a multipath radio channel.
A new high-performance fault-tolerant ATM switching network is proposed. This network contains the baseline network and has many redundant switching elements to enhance the fault tolerance and throughput of the conventional multistage interconnection networks. The presented routing algorithm is very simple and can support a very huge number of paths between each input-output pair. The paths can be used to route cells when internal cell contentions occur in switching elements. The redundant switching elements at the last stage offer two access points to the output ports to resolve the output conflict. Performance analysis and simulation results show that this network has better maximum throughput even for faulty conditions. Among various networks, it has the largest number of redundant paths, and the greatest unit node contribution and unit edge contribution.
Hiroo INABA Shinji SAITOH Toshiyuki KITAHARA Akira KASHIWAGI
A particulate recording medium with an ultrathin magnetic layer is presented in this paper. This medium consists of a magnetic layer and a nonmagnetic underlayer composed of very fine titanium dioxide powder. When metal powder was employed, we observed the anticipated advantages of decreasing the thickness of the magnetic layer in tapes and diskettes. By reducing the layer thickness to below 0.3 µm we were able to increase the reproduced output at short wavelengths, and improve both the overwrite erasability and the D50. There was also a decrease in the half peak width of an isolated pulse and a peak shift. Tribological advantages were also observed with this medium. When barium ferrite was employed as the magnetic powder, we observed that the modulation noise of thin-layer barium ferrite medium was less than that of a thinlayer MP medium while it generated an output as high as that of the MP medium. The advantages of the barium ferrite medium lie in its two-layer construction. Particulate media will continue to develop as magnetic powder is improved mainly in terms of its size, saturation magnetization, and coercivity.
A typed, object-oriented database technology, equipped with appropriate declarative, temporal logic based executable constraints, is presented. The underlying object-oriented database type system is based on advanced features such as subtype, parametric and F-bounded polymorphism. A particularly distinctive feature of the type system is its associated type-safe reflection technology, which provides the flexibility required by database operators without sacrificing type safety. Strongly, and even statically typed, executable class specifications of a variety of standard database abstractions, both application-oriented and system-oriented, are presented in the paper, in order to demonstrate strate the applicability of the paradigm. The temporal logic basis of the constraint language has an execution model, as well as the minimal model semantics, and it allows complex, temporal behavioral patterns to be expressed. It is based on three tomporal operators: always, next time and some time, and rules that determine how these operators may be applied in temporal Horn clauses. Because of the object-oriented nature of the paradigm, the logic basis is also equipped with the equality predicate The proposed technology is intended to provide major advantages not only in managing appropriately complex application environments with temporal constraints, but also in providing more efficient (because of static type checking) and reliable database management systems. It offers the advantages of non-procedural data languages and the richness of a temporal object-oriented paradigm. It also leads to a powerful prototyping tool for structural and behavioral testing of complex, strongly typed object-oriented systems, prior to major procedural implementation efforts.
Naohisa OTSUKA Hiroshi INABA Kazuo TORAICHI
The disturbance-rejection problem is to find a feedback control law for linear control systems such that the influence of disturbances is completely rejected from the output. In 1970 Wonham and Morse first studied this problem in the framework of the so-called geometric approach. On the other hand, in 1985 Ghosh studied parameter insensitive disturbance-rejection problems with state feedback and with dynamic compensator. In this paper we study the parameter insensitive disturbance-rejection problem with static incomplete-state feedback for linear multivariable systems in the framework of the geometric approach from the mathematical point of view. Necessary conditions and/or sufficient conditions for this problem to be solvable are presented. Finally an illustrative example is presented.
Koichi KARAKI Hiroko SASAKI Masaharu MITSUNAGA
A real-time read/write motion picture has been demonstrated by hole-burning holography using cryogenic Eu3+: Y2SiO5 crystal. In a holographic configuration the laser frequency was continuously scanned within the 7F0-5D0 absorption line while the object was in motion. This movie has no picture frames, and therefore is temporally continuous. This feature allows realization of high-speed and high-time-resolution motion recording.
Kazuaki TAKAO Hiromichi MATSUDA
In this paper, we analyze the convergence behavior of the CMA (Constant Modulus Algorithm) adaptive array working under the steepest decent method, and investigate how to achieve the highest possible output SINR (Signal to Interference plus Noise Ratio). In multipath radio environments, CMA sometimes suppresses the desired signal (stronger one) and selects to receive the interference (the weaker one) resulting in the low output SINR. This is one of the problems met in an optimization system under a nonlinear control equation where there are two or more local minima of the cost function and the final state depends on the initial condition. The study can be done only numerically by starting from various initial values. In our analysis of the CMA adaptive array in multipath radio environments, we will assume that there are two waves which are radiated from the same source and try to find out what conditions may affect the convergence behavior. In this process, we discover the effect of the neglected factor by the previous papers and revise the initial condition to guarantee the reception of the desirable wave. In conclusion, we propose the prescription of the initial weights of the array elements as well as the choice of preferable arrays.
This paper describes a new intelligent computer assisted instruction (ICAI) system for Japanese beginners to learn Korean composition. This system is supported by speech synthesis which is generated by a new method for arbitrary sentences of Japanese and Korean using the natural speech data-base.
Masatoshi ARIKAWA Ken'ichi HORIKAWA Yahiko KAMBAYASHI
Queries to generate a map from geographic detabases are too large and complex for users to specify all components in it. Thematic parts of the map should be described by users as ad hoc queries. However, background parts of it should be inferred from users' queries corresponding to the thematic parts. Furthermore, it is important for the map systems to lead users' constructing their ad hoc queries and to infer visualization methods applied to the data retrieved by the ad hoc queries. This paper discusses a framework to infer supplemental queries and visualization methods in order to make the retrieval results into a feasible map using geographic domain hierarchical levels, geographic domain thesauruses and existing example queries. The framework allows users to know mismatches of components in queries, inappropriate queries for maps, and deriving candidates for additional components in queries.
Tremendous progress has been made in magnetic data storage by applying theoretical considerations to technologies accumulated empirically through a great deal of research and development. In Japan, the recording demagnetization phenomenon was eagerly analyzed by many researchers because it was a serious problem in analogue signal recording such as video tape recording using a relatively thick magnetic recording medium. Consequently, perpendicular magnetic recording was proposed as a method for extremely high-bit-density recording. This paper describes the theoretical background which has resulted in the idea of perpendicular magnetic recording. Furthermore, the possibility of magnetic recording is discussed on the basis of the results obtained theoretically by magnetic recording simulators. Magnetic storage has the potential for extremely high-bit-density recording exceeding 1 Tb/cm2. We propose the idea of 'spinic data storage' in which binary digital data could be stored into each ferromagnetic single-domain columnar particle when the perpendicular magnetizing method is used.
Lira HAMADA Meng-Shien WU Koichi ITO Haruo KASAI
The interstitial hyperthermia is an invasive heating method applied by inserting the applicator into the human body. We have been studying on coaxial-slot antennas for interstitial microwave hyperthermia. The characteristics of the square antenna array were theoretically examined. Firstly, the basic structure of the antenna, and a simplified analysis model taking account of the effect of the boundary surface were explained. Then analysis was performed by using the moment method. Finally, the calculated results were discussed. The catheter thickness has much effect on the characteristics and must be considered both in designing and in using the antenna. When the array spacing was increased, the effective heating area became larger and more uniform. As the insertion depth was increased, the effective heating area was also enlarged.
Koichiro WAKABAYASHI Hisataka SUGIYAMA Atsushi SAITO Takeshi MAEDA
A two-dimensional recording method that achieves double recording density by reducing the track pitch is described. This method uses a flat disk and the data are recorded with circular marks on lattice points. Two-dimensional interference consisting of crosstalk and inter-symbol interference is reduced by two-dimensional equalization. To minimize the two-dimensional interference, the optimum equalization coefficients are calculated dynamically with the reproduced signal of the training marks. Reproduction was simulated and this showed that the signal-to-noise ratio of the processed signal was 24.3 dB under ideal conditions and 19.8 dB under worst-case conditions with the usual magneto-optical media using double recording density. These simulation results were checked by a recording/reproduction experiment. The experimental result for the signal-to-noise ratio of the processed signal was 23.6 dB with an areal density of 2.3 Gbit/in2.
Katsuyoshi MIURA Koji NAKAMAE hiromu FUJIOKA
An automatic transistor-level performance fault tracing method is proposed which is applicable to the case where only CAD layout data is available in the CAD-linked electron beam test system. The technique uses an integrated algorithm that combines a previously proposed transistor-level fault tracing algorithm and a successive circuit extraction from CAD layout data. An expansion of the algorithm to the fault tracing in a combined focused ion beam and electron beam test system which enables us to measure signals on the interconnections in the lower layers is also described. An application of the technique to a CMOS model layout with about 100 transistors shows its validity.
Hiroshi ISHIKAWA Kazumi KUBOTA Koki KATO
Our objective is to resolve three types of heterogeneity - data model,database system, and semantic - in heterogeneous databases. The basic framework which we propose for this objective is realized in an autonomous decentralized database system (i.e., an interoperable database system), called Jasmine/M. Users describe their relational or object-oriented data models and schemas locally using the model primitives which Jasmine/M provides as a scripting language. Description using such primitives or scripts constitutes viewports, which have a role to resolve heterogeneity in data models and database systems at local sites. At relational viewports, both relational and object-oriented schemas defined at other sites are translated via scripts and are viewed as relational schemas. Similarly at object-oriented viewports, any schema defined at other sites is viewed object-oriented schemas. Relational and object-oriented views are used to resolve semantic heterogeneity within viewports. This paper describes a step wise approach to resolving the three types of heterogeneity, using scripts, viewports, and views, and its implementation using active objects.
Shigeki NAKAGAWA Masahiko NAOE
Co-Zr and Co-Zr-Ta amorphous films were prepared by the Kr sputtering method for use as the backlayers of Co-Cr perpendicular magnetic recording tape media. The effect of the addition of Ta to Co-Zr thin films was also investigated. Lower substrate temperature was required to prepare amorphous Co-Zr films with excellent soft magnetic properties. The relationships among Ta content X, magnetostriction constant λ and magnetic characteristics such as coercivity Hc and relative permeability µr were clarified. A method of evaluating λ of soft magnetic thin films deposited on polymer sheet substrate has been presented. Films with composition of (Co95.7Zr4.3) 100-X TaX at X of 10 at.% possessed sufficiency soft magnetic properties such as low Hc below 80 A/m and high µr above 600. Addition of Ta was effective in changing change the sign of λ from positive to negative. It was found that the negative magnetoelastic energy and the smaller λ caused the soft magnetism.
Toshio ANDO Makoto MIZUKAMI Toshikazu NISHIHARA
The authors have studied the demagnetization phenomenon which is observed in a conventional CoCrTa/CoZrNb double-layered (DL) perpendicular recording medium. The authors have also investigated the effects of an in-plane hard magnetic layer in a triple-layered (TL) perpendicular recording medium. The in-plane hard magnetic underlayer is made of CoSm or CoCrTa/Cr and is laid under the CoZrNb soft magnetic layer. In the DL medium, a demagnetization phenomenon i.e. decrease of the readback signal, is observed when the CoCrTa layer has a strong perpendicular orientation and the CoZrNb underlayer has a low coercivity. The amount of the signal decrease depends strongly on the accumulated disk revolutions. This demagnetization is considered to be caused by fact that the recorded magnetization in the CoCrTa layer is reduced by the magnetic field generated from the domain walls in the CoZrNb layer, since the CoZrNb layer is very sensitive to a magnetic environment such as geo-magnetism and domain walls move as the disk rotates. On the other hand in the TL medium, the hard magnetic layer has an effect of pinning the magnetic domain in the CoZrNb layer, by which the demagnetization problem is successfully prevented. The hard magnetic layer remarkably reduces the domain walls in the CoZrNb layer and contributes to medium noise reduction. Thus the TL medium presents a higher SN ratio than DL medium.