New network survivability measures are developed and compared with conventional ones. The advantages of using multiple survivability measures, including the new ones, are discussed. The measures are illustrated and interpreted through several numerical examples. We also show how survivability can be included as a constraint in network optimization models.

A modified error correction/detection scheme based on the scheme by Yi and Lee is proposed. Algebraic decoding is used to perform error correction. Error detection is performed by an absolute value test. It is shown that the proposed scheme bridges the performance gap between Yi and Lee's scheme and Forney's optimal scheme.

Thermally-diffused expanded core (TEC) techniques brought the fibers with the mode fields expanded by thermal diffusion of core dopants. The techniques are effective to the reduction of splice or connection losses between the different kind of fibers, and are applied to the integrations of thin film optical devices in fiber networks, the fabrications of chirped fiber gratings, and so on. In the practical use of TEC techniques, the fibers are heated high temperature of about 1650 because of a short peried of time in processing by microburners. The mode field diameter expansion (MFDE) ratio, which is defined as the ratio of the mode field diameter in the fiber section having the core expanded and that unexpanded, is desired to be more than 2.0 from the viewpoint of loss reduction in industrial uses of the TEC techniques. When the TEC techniques are applied to polarization-maintaining optical fibers (PM fibers), such as PANDA fibers, both core dopants and stress applying part (SAP) dopants diffuse simultaneously. So the MFDE ratio is less than two without mode field deformation in conventional PANDA fibers which are practically used as PM fibers. In this paper a PANDA fiber design suitable for the TEC techniques is newly proposed. The fiber has 1.28 µm cutoff wavelength and the mode field diameter is about 11 µm before core expansion at 1.3µm wavelength.

Analog inverter is one of the most useful building blocks in analog circuits. This paper proposes an analog inverter consisting of a p-channel MOS (PMOS) and an n-channel MOS (NMOS) inverter and presents an application to all-pass filter realizations. The proposed circuit has a wide dynamic range by combining PMOS and NMOS inverters. When the proposed analog inverter is applied to an all-pass filter, the circuit configuration becomes simpler and occupies less chip area and power consumption.

In this paper, we investigate inverse problems of the interval query problem in application to data mining. Let I be the set of all intervals on U = {1, 2, , n}. Consider an objective function f(I), conditional functions ui(I) on I, and define an optimization problem of finding the interval I maximizing f(I) subject to ui(I) > Ki for given real numbers Ki (i = 1, 2, , h). We propose efficient alogorithms to solve the above optimization problem if the objective function is either additive or quotient, and the conditional functions are additive, where a function f is additive if f(I) = ΣiIf^(i) extending a function f^ on U, and quotient if it is represented as a quotient of two additive functions. We use computational-geometric methods such as convex hull, range searching, and multidimensional divide-and-conquer.

In this paper the design of systolic array processors for computing 2-dimensional Discrete Fourier Transform (2-D DFT) is considered. We investigated three different computational schemes for designing systolic array processors using systematic approach. The systematic approach guarantees to find optimal systolic array processors from a large solution space in terms of the number of processing elements and I/O channels, the processing time, topology, pipeline period, etc. The optimal systolic array processors are scalable, modular and suitable for VLSI implementation. An application of the designed systolic array processors to the prime-factor DFT is also presented.

In ATM networks, a usage parameter control (UPC) strategy must regulate incoming traffic according to the characteristics of the sources declared at call set-up. Among various UPC schemes, Leaky Bucket is a conventionally method having been discussed extensively. This paper examines the characteristics of the multiplexer with a sufficient buffer in which cell arrivals are policed by Enhanced Leaky-Bucket (ELB) before entering the system. In addition to the factor of mean rate, peak rate and cell delay variation (CDV) are also considered for each ELB. We find out the worst output pattern from the ELB and derive the upper bound on average waiting time as a function of the ELB parameters.

Because a massively parallel computer processes vast amounts of data and generates many access requests from multiple processors simultaneously, parallel secondary storage requires large capacity and high concurrency. One effective method of implementation of such secondary storage is to use disk arrays which have multiple disks connected in parallel. In this paper, we propose a parallel file access method named DECODE (dynamic express changing of data entry) in which load balancing of each disk is achieved by dynamic determination of the write data position. For resolution of the problem of data fragmentation which is caused by the relocation of data during a write process, the concept of "Equivalent Area" is introduced. We have performed a preliminary performance evaluation using software simulation under various access statuses by changing the access pattern, access size and stripe size and confirmed the effectiveness of load balancing with this method.

MPO optical backplane connectors using multi-fiber push-on plugs (MPO plugs) have been developed. MPO optical backplane connector is a connector connecting a printed board to a backplane using MPO plug. MPO plug is held in the housing with self-retentive mechanism. To get same optical performances as standard MPO connector, precision in dimension and mechanism for appropriate connecting-disconnecting sequence are necessary. We have developed a new backplane housing and printed board housing based on previously reported MU connector. The optical performance is similar to that of MPO connectors.

Compressible viscous flows past a space plane have been elucidated by parallel computation on the NWT. The NWT is a vector-parallel architecture computer system which achieves remarkably high performance in processing speed and memory storage. We have examined the advantages of the NWT in order to simulate realistic flow problems in engineering, such as the investigation of global and local aerodynamic characteristics of a space plane. The accuracy of the computational results has been verified by comparison with experimental data. The simplified domain-decomposition technique introduced here is easy to apply for parallel implementation to significantly improve the acceleration rate of computations. The larger available memory storage enables us to conduct a grid refinement study through which several points concerning CFD simulation of a space plane are obtained.

This paper proposes a new method for recovering the original signals from their linear mixtures observed by the same number of sensors. It is performed by identifying the linear transform from the sources to the sensors, only using the sensor signals. The only assumption of the source signals is basically the fact that they are statistically mutually independent. In order to perform the 'blind' identification, some time-correlational information in the observed signals are utilized. The most important feature of the method is that the full information of available time-correlation data (second-order statistics) is evaluated, as opposed to the conventional methods. To this end, an information-theoretic cost function is introduced, and the unknown linear transform is found by minimizing it. The propsed method gives a more stable solution than the conventional methods.

It is shown that two-dimensional linear phase FIR digital filters with various shapes of frequency response can be designed and realized as modular array structures free of multiplier coefficients. The design can be performed by judicious selection of two low order linear phase transfer functions to be used at each module as kernel filters. Regular interconnection of the modules in L rows and K columns conditioned with boundary coefficients 1, 0 and 1/2 results in higher order digital filters. The kernels should be chosen appropriately to, first, generate the desired shape of frequency response characteristic and, second, lend themselves to multiplierless realization. When these two requirements are satisfied, the frequency response can be refined to possess narrower transition bands by adding additional rows and columns. General properties of the frequency response of the array are investigated resulting in Theorems that serve as valuable tools towards appropriate selection of the kernels. Several design examples are given. The array structures enjoy several favorable features. Specifically, regularity and lack of multiplier coefficients makes it suitable for high-speed systolic VLSI implementation. Computational complexity of the structure is also studied.

We extend the Rabin cryptosystem to the Eisenstein and Gauss fields. Methods for constructing the complete representation class and modulo operation of the ideal are presented. Based on these, we describe the methods of encryption and decryption. This proposed cryptosystem is shown to be as intractable as factorization, and recently presented low exponent attacks do not work against it.

RF integration, until recently the integration of active devices in conventional architectures suitable for discrete-component circuits, is now turning into full-integration based on new architectures developed specifically for an LSI technology. This paper reviews some of the key existing and emerging circuit techniques and discusses the serious problem of crosstalk. In order to develop miniature and low power RF transceivers, direct-conversion and monolithic VCO's will be further studied. Silicon bipolar technology will still be playing major role beyond the year 2,000, and CMOS will also be used in certain applications.

The numerical properties of the recursive least squares (RLS) algorithm and its fast versions have been extensively studied. However, very few investigations are reported concerning the numerical behavior of the predictor based least squares (PLS) algorithms that provide the same least squares solutions as the RLS algorithm. This paper presents a comparative study on the numerical performances of the RLS and the backward PLS (BPLS) algorithms. Theoretical analysis of three main instability sources reported in the literature, including the overrange of the conversion factor, the loss of symmetry and the loss of positive definiteness of the inverse correlation matrix, has been done under a finite-precision arithmetic. Simulation results have confirmed the validity of our analysis. The results show that three main instability sources encountered in the RLS algorithm do not exist in the BPLS algorithm. Consequently, the BPLS algorithm provides a much more stable and robust numerical performance compared with the RLS algorithm.

In this paper, we propose a handoff scheme with two-level priority for the reservation of handoff request calls in mobile cellular radio systems. We assume two types of mobile subscribers with different distributions of moving speed, that is, users with low average moving speed (e.g., pedestrians) and high average moving speed (e.g., people in moving cars). A fixed number of channels in each cell are reserved exclusively for handoff request calls. Out of these number of channels, some are reserved exclusively for the high speed handoff request calls. The remaining channels are shared by both the originating and handoff request calls. In the proposed scheme, both kinds of handoff request calls make their own queues. The system is modeled by a three-dimensional Markov chain. We apply the Successive Over-Relaxation (SOR) method to obtain the equilibrium state probabilities. Blocking probabilities of calls, forced termination probabilities and average queue length of handoff calls of each type are evaluated. We can make the forced termination probabilities of handoff request calls smaller than the blocking probability of originating calls. Moreover, we can make the forced termination probability of high speed handoff request calls smaller than that of the low speed ones. Necessary queue size for the two kinds of handoff request calls are also estimated.

Highly parallel scalable multiprocessing systems (HMPs) are powerful tools for solving large-scale scientific and engineering problems. However, these machines are difficult to program since algorithms must exploit locality in order to achieve high performance. Vienna Fortran was the first fully specified data-parallel language for HMPs that provided features for the specification of data distribution and alignment at a high level of abstraction. In this paper we outline the major elements of Vienna Fortran and compare it to High Performance Fortran (HPF), a de-facto standard in this area. A significant weakness of HPF is its lack of support for many advanced applications, which require irregular data distributions and dynamic load balancing. We introduce HPF +, an extension of HPF based on Vienna Fortran, that provides the required functionality.

A factorization method for a string polynomial called the constant method is proposed. This uses essentially three operations; classification of monomials, gcrd (greatest common right divisor), and lcrm (least common rigth multiple). This method can be applied to string polynomials except that their constants cannot be reduced to zeros by the linear transformation of variables. To factorize such excluded string polynomials, the naive method is also presented, which computes simply coefficients of two factors of a given polynomial, but is not efficient.

This paper deals with an orthogonal functional expansion of a non-linear stochastic functional of a stationary binary sequence taking 1 with equal probability. Several mathematical formulas, such as multi-variate orthogonal polynomials, recurrence formula and generating function, are given in explicit form. A simple example of orthogonal functional expansion and stationary random seqence generated by the stationary binary sequence are discussed.

An alternative defuzzification technique for center of gravity calculation is proposed. The technique allows evaluation of fuzzy inferences without the use of multiplication. In fuzzy logic controllers with many outputs, the proposed scheme reduces the circuit complexity compared with other implementations.