Extremely narrow track width of deep submicron range is examined in perpendicular magnetic recording. Head field distribution of a single-pole head analyzed by 3-dimensional computer simulation results in a sharp gradient, but relatively large cross-sectional area is required to maintain head field strength. Based on this design concept, a lateral single-pole head is described and proved to attain track width of 0.4 µm. In addition, multilevel partial response appropriate to the new multitrack recording system is proposed.

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.

High power interference rejection characteristics of a sidelobe canceller which have not been well discussed yet are investigated through computer simulation and experiment in the real radio wave environment. To improve the high power interference rejection performance, a new method is considered. The performance of the method is also analyzed through computer simulation and experiment.

This paper discusses a coding-based selection approach to a communication aid for the severely motor disabled. Several approaches including row-column scanning are briefly described, then we propose a new selection scheme based on the theory of adaptive coding. They are compared each other with respect to average switch activations in generating some text samples.

Generalizations of the classical ngram indexing techique provide a powerful tool for the fast retrieval of tree structures. We investigate the special case of binary trees, which are heavily used, for example, in computer linguistics: Given a database T{t1,...,tn} of labeled binary trees and a query tree q, find efficiently all trees t T that contain q as subtree. For supporting queries of this type, we propose an indexing technique that covers the database trees t T with smaller trees of a fixed calss. Thus, each index record represents a subtree that is contained in at least one database tree. To answer a given query q, the database trees of T that contain all of q's cover trees are preselected as candidates, which in turn are tested rigorously for containment of q. We present results from two test suites: one with databases of 10,000 randomly generated binary trees each and one with the 29,394 most extensive phrase structure trees found in the morphosyntactical analysis of the Old Testament's Hebrew texts Genesis, Exodus,and Leviticus.

A new method is developed to generate fuzzy rules from numerical data. This method consists of two algorithms: Algorithm 1 is used to identify structures of the given data set, that is, the optimal number of rules of system; Algorithm 2 is used to identify parameter of the used model. The former is belonged to unsupervised learning, and the latter is belonged to supervised learning. To identify parameters of fuzzy model, we developed a neural network which is referred to as Unsymmetrical Gaussian Function Network (UGFN). Unlike traditional fuzzy modelling methods, in the present method, a) the optimal number of rules (clusters) is determinde by input-output data pairs rather than by only output data as in sugeno's method, b) parameter identification of ghe present model is based on a like-RBF network rather than backpropagation algorithm. Our method is simple and effective because it integrates fuzzy logic with neural networks from basic network principles to neural architecture, thereby establishing an unifying framework for different fuzzy modelling methods such as one with cluster analysis or neural networks and so on.

This letter describes the power absorption of a cylindrical man model placed near a flat reflector exposed to TE microwave. The numerical results show that the absorption is in some cases an order of magnitude or more greater than that of the man model without a reflector.

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.

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.

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.

Tilt margins for disk and lens for a magneto-optical (MO) head were studied for designing a disk system for use with objective lenses having numerical apertures (NA) of 0.55, 0.60, and 0.65. The tilt margins were examined to determine the aberration characteristics of objective lenses and bit error rate (BER) by recording and reproducing signal. In preparing the optical head for testing disk and lens tilt margins, the aberrations were measured by image processing from the CCD area sensor for the spot image of the focused beam, and BER dependencies on the tilting of lens and disk were obtained at the velocity of the outer diameter of the MO disk at the bit rate of 80-Mbps (1, 7 code modulation) recording. According to the aberration and BER characteristics, the limitation for effective wavefront aberration would be 0.05λ rms, the tilt margins corresponded to BER limitation at the level of 3*10-5. The disk margins for NA=0.55, 0.6, and 0.65 were 0.4, 0.2, and 0.1 degrees. The lens tilt margins for NA=0.55, 0.6, and 0.65 were 0.2, 0.1, and 0.05 degrees.

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.

Analyzing multipath propagation structure is important to develop anti-fading techniques for high-speed digital radio systems. Several techniques have been employed to measure delay profiles and/or arrival angles. This paper presents a simultaneous estimation method of delay times and arrival angles of indoor multipath waves. We obtain frequency-domain data at different receiving antenna positions using a network analyzer. We estimate the propagation parameters by means of a two-dimensional MUSIC algorithm. In order to obtain reliable results, a two-dimensional discrete inverse Fourier transform and a gating technique are employed before the MUSIC algorithm. Simulation and experimental results show that the proposed method can estimate the propagation parameters properly.

Computer circumstance have changed drastically, and larger capacity removable media is indispensable. Magneto-optical disk is promising candidate to satisfy computer user's needs. In this report, future perspective of high density magneto-optical recording technology is investigated.

Conventional subband ADF's (adaptive digital filters) using filter banks have shown a degradation in performance because of the non-ideal nature of filters. To solve this problem, we propose a new type of subband ADF incorporating two types of analysis filter bank. In this paper, we show that we can design the optimum filter bank which minimizes the LMSE (least mean squared error). In other words, we can design a subband ADF with less MSE than that of conventional subband ADF's.

This paper describes a simulation technique of start-up characteristics that considers a nonlinearity of the drive level of quartz crystal resonators. A nonlinear resonator model for SPICE where the resonant resistance varies with the voltage added to a resonator is proposed. In an examination using a transistor Colpitts oscillator, the simulation using this technique agreed with the experimental results very well.

As the Hypertext Transfer Protocol (HTTP) becomes more popular for network communication, network loads in areas with less developed network infrastructures will be an increasing problem. This paper presents a system which extends a WWW-server with a gateway to an RDBMS and a mail program, allowing for interactive query formulation together with return of potentially large query results by e-mail. These results can then be downloaded by the user when network loads are low.

The evolution of heterogeneous and autonomous databases research has been slow compared to other areas of research. Part of the problem resides in the fact that bridging data semantics has been a difficult problem. Sharing data among disparate databases has mostly been achieved through some form of manual schema integration. The complexity of making autonomous heterogeneous databases smoothly interoperate is dependent on addressing two major issues. The first issue to address is what adequate levels of autonomy databases are guaranteed to keep. The second issue to address is what overhead cost is required to bridge database heterogeneity. The complexity of these two issues are closely dependent on how scalable multidatabase systems are. In this paper we introduce the FINDIT architecture which uses information meta-types to provide a basis for such an organization and, consequently, provides a platform for inter-operability. A distinction is made between the information and inter-node relationship spaces to achieve scalability. Tassili language primitives are used for the incremental building of dynamic inter-node relationships based upon usage considerations.

In order to make the hyperling generation mechanism not only dynamic but also systematic, we will mainly describe the use of the querying and abstraction facilities in hypertext database systems. Our work focuses on a dynamic, abstract and systematic link generation mechanism. The prototype system named TextLink/Gem is implemented by taking an object-oriented approach, and the notions of anchor objects, query-pair links, polymorphic links and inheritable links, on which the system is based, and their implementations are described in detail.

This paper describes the architecture and storage structure of a new interactive multimedia information system called VideoReality. VideoReality is based on a visual conducting model, which describes the information retrieval process that occurs when people observe visible objects in the real world. VideoReality provides a spatial and temporal spread of a virtual video space from a set of stored video streams. The video space has a three-layered structure similar to that of the ANSI/X3/SPARC three-schema architecture. Users can move their eyes and watch objects freely in the video space, just as if they were viewing the real world. This paper also presents a prototype application system called Electronic Aquarium'