THe decimation-in-time (DIT) and the decimation-in-frequency (DIF) algorithms are the most well-known fast algorithms for computing the discrete Fourier transform(DFT). These algorithms constitute the basis of the fast Fourier transform (FFT) implementations, including the pipeline implementation and other parallel configurations. This paper derives an alternative generalization of the algorithms which applies for sequences whose lengths are not a power of two. The treatment is consistent with the radix-two DIF and DIT algorithms, and the generalization is useful for utilizing the accumulated technologies of the FFT algorithm for such sequences.

The effect of silicone vapour concentration on the contact failure was examined by using micro relays and motor brush-slip ring(commutator) contacts, [(CH3) 2SiO]4: D4 was used as a vapour source of silicone contamination. Because the influence of the vapour of the silicone on the contact surface can not be avoided at all times due to its gradual evaporation in the atmosphere. The contact failure caused by the silicone vapour was confirmed as formation of SiO2 on the contact surfaceby analysis of EPMA and XPS. A minimum limiting concentration level which does not affect contact reliability was found. This limiting level was 10 ppm(O.13mg/l). Validity of the limiting level was confirmed by the relationships among concentration, temperature, SiO2 film thickness and contact resistance. Furthermore, the effect of the degree of silicone polymerization on the limiting concentration was derived by an empirical formula. This silicone is found to have polymerization degree larger than D7: n=7. These results were confirmed by the contact failure data due to the silicone contamination.

This paper proposes new algorithms for diagnosing (detection, identification and location) baseline multistage interconnection networks (MIN) as one of the basic units in a massively parallel system. This is accomplished in the presence of single and multiple faults under a new fault model. This model referred to as the geometric fault model, considers defective crossing connections which are located between adjacent stages, internally to the MIN (therefore, a fault corresponds to a physical bridge fault between two connections). It is shown that this type of fault affects the correct geometry of the network, thus requiring a different testing approach than previous methods. Initially, an algorithm which detects the presence of bridge faults (both in the single and multiple fault cases), is presented. For a single bridge fault, the proposed algorithm locates the fault except in an unique pathological case under which it is logically impossible to differentiate between two equivalent locations of the fault (however, the switching element affected by this fault is uniquely located). The proposed algorithm requires log2 N test vectors to diagnose the MIN as fault free (where N is the number of input lines to the MIN). For fully diagnosing a single bridge fault, this algorithm requires at most 2 log2 N tests and terminates when multiple bridge faults are detected. Subsequently, an algorithm which locates all bridge faults is given. The number of required test vectors is O(N). Fault location of each bridge fault is accomplished in terms of the two lines in the bridge and the numbers of the stages between which it occurs. Illustrative examples are given.

The objective of this paper is to find a parametric representation for the vocal-tract log-area function that is directly and simply related to basic acoustic characteristics of the human vocal-tract. The importance of this representation is associated with the solution of the articulatory-to-acoustic inverse problem, where a simple mapping from the articulatory space onto the acoustic space can be very useful. The method is as follows: Firstly, given a corpus of log-area functions, a parametric model is derived following a factor analysis technique. After that, the articulatory space, defined by the parametric model, is filled with approximately uniformly distributed points, and the corresponding first three formant frequencies are calculated. These formants define an acoustic space onto which the articulatory space maps. In the next step, an independent component analysis technique is used to determine acoustic and articulatory coordinate systems whose components are as independent as possible. Finally, using singular value decomposition, acoustic and articulatory coordinate systems are rotated so that each of the first three components of the articulatory space has major influence on one, and only one, component of the acoustic space. An example showing how the proposed model can be applied to the solution of the articulatory-to-acoustic inverse problem is given at the end of the paper.

We develop a simulation environment for designing and examining a neural network model at the network level. The aim of our research is to enable researchers investigating neural network connective models to save time by being equipped with a graphical user interface and database of the network models. This environment consists of three parts: (1) the kernel of the simulation system, (2) NNDBMS (Neural Networks DataBase Management System), and (3) a system for displaying simulation results in various ways.

Various reconfiguration schemes against faults of mesh-connected processor arrays have been proposed. As one of them, the mesh-connected processor arrays model based on single-track switches was proposed in [1]. The model has an advantage of its inherent simplicity of the routing hardware. Furthermore, the 2 track switch model [2] and the multiple track switch model [3] were proposed to enhance yields and reliabilities of arrays. However, in these models, Simplicity of the routing hardware is somewhat lost because multiple tracks are used for each row and column. In this paper, we present a builtin self-reconstruction approach for mesh-connected processor arrays which are partitioned into sub-arrays each using single-track switches. Spare PEs which are located on the boundaries of the sub-arrays compensate faulty PEs in these sub-arrays. First, we formulate a reconfigulation algorithm for partitioned mesh-arrays using a Hopfield-type neural network, and then its performance for reconfigulation in terms of survival rates and reliabilities of arrays and processing time are investigated by computer simulations. From the results, we can see that high reliabilites are achieved while processing time is a little and hardware overhead (links and switches) required for reconstruction is as same as that for the track switch model. Next, we present a hardware implementation of the neural algorithm so that a built-in self-reconfigurable scheme may be realized.

The order of faults which are targeted for test-pattern generation affects both of the processing time for test generation and the number of generated test-patterns. This order is referred to as a test generation schedule. In this paper, we consider the effect of scheduling in test generation. We formulate the test generation scheduling problem which minimizes the cost of testing. We propose schedulings based on test-pattern generation time, dominating probability and dominated probability, and analyze the effect of these schedulings. In the analysis, we show that the total test-pattern generation time and the total number of test-patterns can be reduced by the scheduling according to the descending order of dominating probability prior to the ascending order of test-pattern generation. This is confirmed by the experiments using ISCAS'85 benchmark circuits. Further, in the experiments, we consider eight schedulings, and show that the scheduling according to the ascending order of dominated probability is the most effective of them.

To enhance fabrication yield for processor arrays, many reconfiguration schemes for replacing faulty processing elements (PE's) with spare PE's have been proposed. An array grid model based on single-tracks is one of such models. For this model, some algorithms for reconfiguring processor arrays have been proposed. However, an algorithm which can reconfigure the array, whenever the array is reconfigurable, has not been proposed yet. This paper presents two types of methods for reconfiguration of processor arrays. Both the types use indirect replacements for reconfiguring arrays. For an indirect replacement of a faulty non-spare PE, one has a fixed direction, the other has at most four directions among which one is chosen. For the former, we consider the several distribution of spare PE's, and computer simulations show a tendency in the term of difference in the distributions. The latter algorithms consist of two phases. In the first phase, rows and columns of spare PE's are decided in accordance with a rule. Several rules for deciding spare PE's are considered in this paper. In the second phase, faulty non-spare PE's are replaced with healthy spare PE's. By simulations the performance of the algorithms are evaluated and a tendency is shown in the terms of difference in disposition of spare PE's.

Motivated by the design of fault-tolerant multiprocessor interconnection networks, this paper considers the following problem: Given a positive integer t and a graph H, construct a graph G from H by adding a minimum number Δ(t, H) of edges such that even after deleting any t edges from G the remaining graph contains H as a subgraph. We estimate Δ(t, H) for the hypercube and torus, which are well-known as important interconnection networks for multiprocessor systems. If we denote the hypercube and the square torus on N vertices by QN and DN respectively, we show, among others, that Δ(t, QN) = O(tN log(log N/t + log 2e)) for any t and N (t 2), and Δ(1, DN) = N/2 for N even.

In this paper, we study the following node-to-node and node-to-set routing problems in r-dimensional torus Trn with r 2 and n 4 nodes in each dimension: given at most 2r - 1 faulty nodes and non-faulty nodes s and t in Trn, find a fault-free path s t; and given at most 2r - k faulty nodes and non-faulty nodes s and t1,..., tk in Trn, find k fault-free node-disjoint paths s ti, 1 i k. We give an O(r2) time algorithm which finds a fault-free path s t of length at most d(Trn) + 1 for the node-to-node routing, where d(Trn) is the diameter of Trn. For node-to-set routing, we show an O(r3) time algorithm which finds k fault-free node-disjoint paths s ti, 1 i k, of length at most d(Trn) + 1. The upper bounds on the length of the found paths are optimal. From this, Rabin diameter of Trn is d(Trn) + 1.

Precise direct mounting of laser diode (LD) and photodiode (PD) chips on silica planar lightwave circuits (PLCs) has been investigated for application to transceiver modules. To achieve submicron optical alignment, self-aligned index marks on the PLCs and LDs were directly detected by transmission infrared light. The repeatability of the positioning was measured to be within 0.125 µm. The output power of the resultant module was 0.2 mW at 80 mA. A waveguide-type PD was also mounted in the same way, and module sensitivity of 0.25 A/W was demonstrated.

We present a volume rendering algorithm which renders images at approximately two to seven times the speed of a conventional ray caster with almost no visible loss of image quality. This algorithm traverses the volume data in object order and renders the image by performing ray casting for the pixels within the footprint of the voxel (i.e., rectangular prism) being processed. The proposed algorithm supports the rendering of both single and multiple isosurfaces with arbitrary opacity values. While the projection approach to volume rendering is not new, we present an algorithm specifically designed for the perspective projection, evaluate its rendering speed for both single and multiple isosurfaces with arbitrary opacity values, and examine how efficiently it uses cache memory.

String grammars (languages) have been extensively studied from the 60's. On the other hand, the transformational grammar, proposed by N. Chomsky, contains the transformation from the set of derivation trees of a context-free language to the surface set. Here the grammar regarded a tree as an input sentence to some transducer. After that from the second half of 60's, the studies of acceptors, transducers, and so on, whose inputs are trees, have been done extensively. Recently pushdown tree automata were introduced, and their fundamental and some other various properties were investigated [12],[13],[22]-[26]. Furthermore a top-down pushdown tree transducer (t-PDTT for short), which is an extension of a top-down pushdown automaton (t-PDTA for short), was introduced and its fundamental properties were investigated [27]. In this paper we focus on t-PDTT, linear t-PDTT, t-FST (top-down finite state transducer), and t-PDTA. The main subjects discussed here are as follows: (1) the class of domain/surface tree languages of t-PDTT properly contains the class of tree languages accepted by t-PDTA, (2) the class of domain/surface tree languages of linear t-PDTT's coincides with the class of tree languages accepted by t-PDTA's, (3) the class of tree languages accepted by t-PDTA's properly contains the class of surface tree languages of t-FST's.

An analysis of an imperfectly power controlled DS/CDMA slotted cellular system over the frequency selective Rician fading channel with an error correction coding is performed. The user capacity and packet throughput of reverse link are estimated to show the sensitivity to the power control error in a DS/CDMA system with Rician fading channel. The power control error are modeled with Gaussian random variables, which is a reasonable choice for its proved validity. The relative capacity decrease from the power control error in Rician channel are presented and compared with the results from flat fading channel. Performance results for the model considering multicell interference, pathloss exponent and power ratio of scattered component to direct component are presented.

A method to correct the path-integrated attenuation derived from spaceborne radar measurement for the non-uniform beam filling (NUBF) effect is studied . A preliminary test using the data obtained from shipborne and ground-based radars is performed. It is found that the relation between the coarse-scale variability (radar-measurable quantity, σL) and the fine-scale variability (a quantity necessary for the NUBF correction, σH) of rain depends somewhat upon the rain cases studied and there still remains some underestimation in the corrected results. Nevertheless, the test result demonstrates the potential of utilizing the "local" statistical properties of rain in order to decrease the bias error in rain rate estimation caused by the NUBF.

This paper describes methods in which natural language is used to describe video contents, knowledge of which is needed for intelligent video manipulation. The content encoded by natural language is extracted by a language analyzer in the form of subject-centered dependency structures which is a language-oriented structure, and is combined in an incremental way into a single structure called a multi-path index tree. Content descriptors and their inter-relations are extracted from the index tree in order to provide a high speed retrieval and flexibility. The content-based video index is represented in a two-dimensional structure where in the descriptors are mapped onto a component axis and temporal references (i.e., video segments aligned to the descriptors) are mapped onto a time axis. We implemented an experimental image retrieval systems to illustrate the proposed index structure 1) has superior retrieval capabilities compare to those used in conventional methods, 2) can be generated by an automated procedure, and 3) has a compact and flexible structure that is easily expandable, making an integration with vision processing possible.

We report two new timing control methods for high-speed synchronous interfaces in view of their application to high-speed synchronous DRAMs. These two new circuits are the measure-controlled DLL and the register-controlled DLL.We quantitatively analyzed the minimum operational cycle time for a synchronous interface, and related the minimum bus cycle time to two factors; the bus-to-clock timing skew, and the unit delay time of the DLL. Based on this analysis, we concluded that the I/O performance can be beyond 400 MHz by suppressing both factors to less than 200 ps.

Here we investigate the unique advantages of our proposed Virtual Space Teleconferencing System (VST) in the area of multimedia teleconferencing, with emphasis to facial emotion transmission and recognition. Specially, we show that this concept can be used in a unique way of communication in which the emotions of the local participant are transmitted to the remote party with higher recognition rate by enhancing the emotions using some intelligence processing in between the local and the remote participants. In other words, we can show that this kind of emotion enhanced teleconferencing systems can supersede face to face meetings, by effectively alleviating the barriers in recognizing emotions between different nations. Also in this paper we show that it is better alternative to the blurred or mosaiced facial images that one can find in some television interviews with people who are not willing to be exposed in public.

This paper presents a vision-based human interface system that enables a user to move a target object in a 3D CG world by moving his hand. The system can interpret hand motions both in a frame fixed in the world and a frame attached to the user. If the latter is chosen, the user can move the object forward by moving his hand forward even if he has changed his body position. In addition, the user does not have to keep in mind that his hand is in the camera field of view. The active camera system tracks the user to keep him in its field of view. Moreover, the system does not need any camera calibration. The key for the realization of the system with such features is vision algorithms based on the multiple view affine invariance theory. We demon-strate an experimental system as well as the vision algorithms. Human operation experiments show the usefulness of the system.

Three dimensional model based coding methods are proposed as next generation image coding methods. These new representations need 3D reconstruction techniques. This paper presents a method that extracts the surfaces of static objects that occlude other objects from a spatiotemporal image captured with straight-line camera motion. We propose the concept of occlusion types and show that the occlusion types are restricted to only eight patterns. Furthermore, we show occlusion type pairs contain information that confirms the existence of surfaces. Occlusion information gives strong cues for segmentation and representation. The method can estimate not only the 3D positions of edge points but also the surfaces bounded by the edge points. We show that combinations of occlusion types contain information that can confirm surface existence. The method was tested successfully on real images by reconstructing flat and curved surfaces. Videos can be hierarchically structured with the method. The method makes various applications possible, such as object selective image communication and object selective video editing.