This paper first discusses the software reusability-based development process in a lifecycle and reusable objects modification process called differentiation. Next, the supporting environment is described. Both the method and the environment allow developers to carry out requirement definitions, specification and implementation in a reusable way. Some quantitative evaluations are given about how productivity and quality have been improved by using this method and environment, based on a number of case studies made on development projects. Reusability has been largely improved by differential specification, and adjustment method and a direct transformation capability.

The problem of presentation view generation over external/conceptual view is discussed for database systems. The presentation view is expressed by a format of a report which is generated as the result of a database query. A new presentation format generation scheme for composite reports is proposed for object-oriented databae systems. The reports can have nested (extended non-first-normal-form) formats. The presentation format should vary at run time, depending on repeating groups and data arrangement. The proposed scheme is based on the idea of dynamic co-referring objects, which uses an object-oriented data model extended to the presentation layer. As important features, various composite reports can be easily derived from databases, and dynamic format modification is possible interactively, even after retrieving the data. The scheme is useful for database applications which require a wide variety of formats for casual queries, where the report generation programming cost will be greatly reduced.

In this paper, we propose a method to simulate the curve surface of the initial height in the movement of the electronic wire bonder using the experimental data. For given measured data (xk, yk, zk (k=1, 2, , m)), we propose an algebraic surface of n-th degree as a methematical model of the initial height surface. The AIC method is a method of evaluating the goodness of a given model. The maximum likelihood model is selected by comparing with the AIC value of each model for n=0, 1, 2, 3, , 11. Useing this model, the initial raise position of the electronic wire bonder can be controlled by computer programing and can make the movement of wire bonder full-automatic. As a resurt, the well-arranged wiring and reliable contacting can be obtained.

An accurate numerical solution is presented for the electromagnetic scattering from infinite strip gratings attached to both sides of a dielectric slab. This structure is a model of polarization discriminating devices. The period of the strips is common to both planes, but the widths and the axes may be different. The direction of propagation and the polarization of an incident plane wave are arbitray. We derive a set of singular integral equations and solve it by the moment method, where the Chebyshev polynomials are successfully used as the basis and the testing functions. This method is accurate and effective owing to the incorporation of the edge condition and the decomposition of the kernel functions into the singular and the regular parts. Numerical calculations are carried out for the purpose of designing polarization discriminators, and it is shown that the band width is widened by decreasing the permittivity of the slab. The cross-polarization characteristics at skew incidence are also discussed.

This letter proposes an improvement of the equivalent source method in order to give an accurate solution for the scattering of an electromagnetic plane wave by a conducting cylinder with edges.

The mode partition noise of 1.3µm distributed feedback laser diodes (DFB LD's), which is induced by the externally reflected light, is studied experimentally and numerically. The mode partition noise is evaluated by the k-value. It is observed that the mode parition noise monotonically increases with the DC bias current when the reflected light affects DFB LD's and the DC bias current is above the threshold current. From the dependence of the k-value on the external power reflection coefficient, it is observed that the k-value dramatically increases when the external power reflection coefficient is above a value which differs from LD to LD. This is closely related to the fact that the tolerance to the externally reflected light depends on the threshold gain difference between the main mode and the dominant side mode.

In case of the system identification problem, such as an echo canceller, estimated impulse response obtained by the frequency-domain adaptive filter based on the circular convolution has estimation error because the unknown system is based on the linear convolution in the time domain. In this correspondence, we consider a sufficient condition to reduce the estimation error.

In this letter, it is clarified that the quantum noise properties of the linear amplification and locking amplification in the injection locked laser process are different. The noise property of the locking amplification is newly given.

We study the most appropriate network architecture for constructing FTTH (Fiber To The Home) networks. We conclude that the Single Star network is the most advantageous for supporting the various services required by subscribers who use broadband signal such as B-ISDN (Broadband-Integrated Services Digital Network). We also study high fiber count cable and low-loss connector which are needed for this network and clarify their requirements. We also show the cable structure, connector structure and connection loss reduction method, which satisfy these requirements. We describe a 4,000-fiber cable with a new structure, a 1,000-fiber one-touch connector, a 40-fiber unit connector and TEC-fiber (Thermally-diffused Expanded Core fiber) which reduces connection loss.

A hybrid integrated optical module composed of a silica-based planar lightwave circuit (PLC), a laser diode with an integrated monitor-photodiode, and a pin-photodiode is fabricated for use in high-performance, compact and cost-effective fiber optic subscriber systems. Its applicability to a wavelength-division-multiplex (WDM) system with a 1.3-µm bi-directional signal and a 1.5-µm one-way signal is demonstrated. The PLC was fabricated by a combination of flame hydrolysis deposition (FHD) and reactive ion etching (RIE), and it simultaneously achieved 1.3-µm/1.5-µm multi/demultiplexing and 1.3-µm Y-branching functions. The optical module exhibited insertion losses of 4.1dB at 1.31µm (including a Y-branch circuit loss of 3dB) and 0.5dB at 1.53µm. An optical output power of more than -4dBm was obtained from the optical module and the crosstalk was sufficiently low at less than -20dB between wavelengths of 1.3µm and 1.5µm. Temperature cycle tests on the optical module showed reliable and stable operation with an optical power fluctuation of less than 0.3dB for 500 cycles.

Surface damage to n-type silicon wafers induced by Reactive Ion Etching (RIE) with CF4 gas was evaluated using X-ray photoelectron spectroscopy (XPS) and the current-voltage (I-V) characteristics of Au/n-Si Schottky diodes fabricated on the damaged surface. The reaction products (SiF, SiF2, and SiF3) in the damaged layer were detected by XPS. Assuming the surface damage on a silicon wafer induced by RIE acts as a donor, the donor density was found to be about 21019 cm-3. The distribution of SiF3 and the donor density in the depth direction were almost equal. The thickness of the damaged layer was about 15 nm. These findings suggest that the donor in the damaged layer on a silicon surface induced by RIE may be SiF3.

Relational query languages like SQL and QUEL require the users to understand the complex detabase structure. This is a burden on end users, especially novice end users who access the database on a casual and infrequent basis. To alleviate the need to know the logical database origanization, this paper proposes the use of a semantic data model, known as the Enhanced Entity-Relationship (EER) model, as a front-end to the relational systems. A formal, high-level Visual Knowledge Query Language (VKQL) has also been designed for this interface. This language provides for knowledge abstraction as the user communicates only domain knowledge with the system without any implication on the storage structure or search strategies. A translation algorithm is also described in this paper to translate VKQL queries to Standard SQL equivalents.

An algorithm is presented for selecting the k-th smallest element of a totally ordered (but not sorted) set of n elements, 1kn, in the case that a special-purpose sorter is used as a coprocessor. When the pipeline merge sorter is used as the special-purpose sorter, we analyze the comparison complexity of the algorithm for the given capacity of the sorter. The comparison complexity of the algorithm is 1.4167no(n), provided that the capacity of the sorter is 256 elements. The comparison complexity of the algorithm decreases as the capacity of the sorter increases.

Operation of a newly proposed semiconductor optical modulator based on absorption control by electron depletion around a p-n junction is demonstrated, forming preliminary structures of waveguide-type as well as panel-type (or surface-illuminated type) devices. The optical absorption is occurred at the intrinsic energy levels in the band structure not at the extended state into the band-gap. Performance of 35 dB on-off extinction ratio for 4 V variation of the applied voltage was obtained in a waveguide type device. Validity of the proposed mechanism were confirmed by getting large change of the absorption coefficient of around 5000 cm-1 over wide wavelength range of 30 nm.

It is well known that the multiple-valued signed-digit (SD) arithmetic circuits have the attractive features of compactness and high-speed operation. However, both of these features have yet to be utilized fully. In this paper, we consider the application of a parallel-structure-based VLSI processor. A high-performance parallel-structure-based multiple-valued VLSI processor using the radix-2 SD number system is proposed. Its compactness makes the parallelism high under chip size limitations in comparison with the ordinary binary arithmetic circuits. Moreover, the speed of the single arithmetic module is very high in the SD arithmetic circuits, so that we can take advantage of the high-speed operation in the parallel-structure-based VLSI processor chip. The multiple-valued bidirectional current-mode technology is used not only in high-speed small sized arithmetic circuits, but also in reducing the number of connections in the parallel-structure-based VLSI processor. The proposed processor is specially developed for real-time digital control, where the performance is evaluated by delay time. Performance estimation using SPICE simulators shows that the delay time of proposed processor for matrix operations such as matrix multiplication is greatly reduced in comparison with a conventional binary processor.

Runlength-limited block codes are investigated. These codes are useful for storing data in storage devices. Since most devices are not noiselss, the codes are often required to have some error-control capability. We consider runlength-limited codes that can correct or detect unidirectional byte errors. Some constructions of such codes are presented.

This paper describes the impact of EDFAs on AM/FM FDM subcarrier multiplexing (SCM) all-fiber video distribution (AFVD) systems. As AM/FM hybrid system using EDFAs which can simultaneously distribute 11 AM-TV channels and 50 FM-TV channels is proposed and discussed. 4-stage amplifier-branch transmission experiments are introduced. The construction and performance of a newly designed 50 channel FM tuner are also presented.

Silicon nitride (SiNx) films have been deposited at lower substrate temperatures (500) by direct (without mercury-sensitization) photo-chemical vapor deposition (photo-CVD) using SiH4 and NH3 with a low-pressure mercury lamp. Films deposited at around 350 have a polymeric structure such as (Si(NH)2)n. Films deposited at 500 were close to stoichiometric Si3N4 with a slight amount of hydrogen. The refractive index and the dielectric constant of films deposited at 500 became almost equal to the values of thermally synthesized Si3N4. The resistivity was as high as 51016 Ωcm. The minimum density of interface states in Al/SiNx/Si MIS (metal-insulator-semiconductor) diodes was estimated to be 91010 cm-2eV-1 by a quasi-static capacitance-voltage measurement. For SiNx films deposited at 300, the density of interface states, which was in the order of 1011 cm-2eV-1 as deposited, decreased by a rapid thermal anneal after the deposition. For Al/SiNx/InP MIS diodes, it was 31011 cm-2eV-1 by high-frequency capacitance-voltage measurements. Direct photo-CVD for SiNx films is promising for low-temperature formation of a gate insulator.

Recently most of the singularities of the equivalent edge currents for flat plates were eliminated by the authors using the paths of most rapid phase variation. A unique direction on the plate was determined for given incidence and observer. This paper extends this method for arbitrary angle wedges and presents the new expressions of the equivalent edge currents. The resultant expressions are valid for any incidence and observation aspects and have no false singularities. Diffraction patterns and radar cross sections of 3-D objects composed of wedges are calculated by using these currents. They show good agreements with experimental data or the results by the other methods.