In the final stages of VLSI testing, improved quality VLSI testing is an important subject for ensuring reliability in the forwarded VLSI market. On the other hand, developments in high integration technology have resulted in an increased number of functional blocks in VLSI devices and an increased number of gates for each terminal. Consequently, it has become more difficult to improve the quality of VLSI tests. We have developed a new test method in addition to conventional testing methods intended for improving the test coverage in VLSI tests. This new test method analyzes the relationship between IDDq (Quiescent Power Supply Current) of DUT and DUT failure by applying the concept of the toggle rate. Accordingly, in this paper we report that the results of IDDq testing confirm a correlation with defect level.

A test system with a fuzzy logic controller is proposed to assure stable outgoing quality as well as to raise throughput. The test system controls the number of items under test in accordance with fuzzy information as well as statistical information about incoming quality and outgoing quality. First, an algorithm, minimum-minimum-the center of gravity-weighted mean method, is studied with both fuzzy reasoning rules and membership functions which are used for the control. Second, characteristics of the test system are verified and examined with computer simulations so that the fuzzy logic control rules are determined to realize sufficient sensitivity to process changes. Third, the control rules are installed in the test management processor which commands test equipment for testing very large scale integrated circuits, with programming language C. The authors have obtained satisfactory results through a trial run using a series of lots of 16 bit micro controller units in an IC manufacturing factory. Finally, they study the stability condition of the fuzzy test system.

We propose a stabilization method of unstable periodic orbits embedded in a chaotic attractor of continuous-time system by using discrete state feedback controller. The controller is designed systematically by the Poincar mapping and its derivatives. Although the output of the controller is applied periodically to system parameter as small perturbations discontinuously, the controlled orbit accomplishes C0. As the stability of a specific orbit is completely determined by the design of controller, we can also use the method to destabilize a stable periodic orbit. The destabilization method may be effectively applied to escape from a local minimum in various optimization problems. As an example of the stabilization and destabilization, some numerical results of Duffing's equation are illustrated.

This letter addresses stability problems of interval matrices stemming from robustness issues in control theory. A quick overview is first made pertaining to methods to obtain stability conditions of interval matrices, putting particular emphasis upon one of them, regularity condition approach. Then, making use of this approach, several new stability criteria, for both Hurwitz and Schur stability, are derived.

This paper describes a model of kanji (Chinese characters) learning, called KASTAM (Knowledge Acquisition and STAbility Model), in order to develop a CAI system which supports a student to stabilize her/his kanji knowledge. KASTAM can handle kanji learning as complementary acquisition and stability processes of kanji knowledge.

Program transformation is a kind of optimization techniques for logic programs, which aims at transforming equally a program into an other form by exploiting some properties or information of the program, so as to make the program cheaper to evaluate. In this paper, a new kind of property of logic programs, called reducibility, is exploited in program transformation. A recursive predicate is reducible if the values of some variables in the recursive predicate are independent to the remainder part and can be detached from the predicate after finite times of expansions. After being proved that the semantic notion of reducibility can be replaced by the syntactic notion of disconnectivity of a R-graph, which is a kind of graph model to represent the behavior of formula expansions, an efficient testing and factoring algorithm is proposed. The paper also extends some existed results on compiled formulas of linear sirups, and compares with some related work.

MRI is a widely used diagnostic imaging modality because it has excellent diagnostic capabilities, is safe to use and generates images not affected by bone artifacts. Images are obtained by utilizing the phenomenon of Nuclear Magnetic Resonance (NMR) by which protons located in a static magnetic field absorb radiofrequency (RF) pulses with a specific frequency and release a part of the energy as a NMR signal. Potentially MRI has the ability to provide functional and metabolic information (such as flow, temperature, diffusion, neuron activity) in addition to morphological information. This paper describes the imaging principles and provides a general outline of some applications: flow imaging, metabolite imaging and temperature imaging.

Recent advances of processing speed and window systems in computers, especially workstations, accelerate multi-media data processing (MMDP). Then, a variety of data such as numerics, characters, voice, video, animation and so on, are processed concurrently in a workstation. In data processings, concurrent execution of transactions is a key to improve through-puts. However, concurrent execution without concurrency control may cause inconsistent results. Thus, the concurrency control must be introduced in such systems. However, in MMDP it is ineffective to adopt previous concurrency control methods for ordinal databases since multi-media data are huge and possess a real-time property. This paper discusses concurrency control for MMDP. We propose some new concepts for MMDP, and define a new serializability class called Permissible Serializability which provides high concurrency in MMDP compared with ordinal classes. Then, we propose a concurrency control algorithm TYPE for the Permissible Serializability, and show some simulation results.

In this letter we propose a stabilizing method of phase control for resistively coupled oscillator networks. To demonstrate the effect of the control, we consider the coupled oscillator system containing only voltage type of connections. A state feedback technique to resistor sub-network is used to control the phase of synchronized oscillation. The technique is applied to two and three coupled oscillator cases. Finally we present experimental results, which agree well with the theory.

In this study, we investigate the synchronization phenomena of coupled Wien bridge oscillators. The oscillator is characterized by a voltage controlled resistor with saturation. We use linear resistance to couple the oscillators. Two different kinds of coupling techniques, called current and voltage connections are proposed and they show completely opposite mode of synchronized oscillations. The dynamics of the two circuits are also derived to study the amplitude and phase dynamics of the synchronized state. The current connection has a simple resistive effect but stable phase mode is opposite to that of the voltage connection. The voltage connection has the coupling effect which is a combination of resistive and reactive couplings. Coupled three oscillators with current and voltage connection are also studied and stable tri-phase and in-phase synchronizations are observed, respectively. Averaging method is used to investigate the stability of synchronized mode of oscillations. Experimental results are also stated which agree well with the theory.

This paper reports an overload control method for the Intelligent Network (IN). The IN, which is being investigated as a future communication network, facilitates both rapid introduction of new services and easy modification of existing services. In the IN, the call processing functions and data needed to achieve IN services are distributed over several nodes. Therefore, traffic demand for the various services may cause varying patterns of node overloads. It is therefore important to develop effective overload control methods and to evaluate their characteristics. We propose an overload control method and evaluate its characteristics in comparison with other methods under various overload traffic patterns with a network simulator that models all nodes and their relationships in the IN. In particular, we focus on three aspects of overload control: how can high throughput be maintained, how can an overloaded node be stabilized, and how can fair access be guaranteed.

Recently as one of attractive applications in the B-ISDN era, LAN/MAN interconnection through an ATM network has been coming up because burstiness of LAN/MAN data traffic is applicable to distinctive features of cell based ATM network. In order to overcome a difference of the connection mode, i.e., CL packet transfer of LAN/MAN and CO cell transfer of ATM network, a number of interworking and bandwidth allocation mechanisms have been proposed. These methods, however, indicate both merits and drawbacks concerning with CL data transfer quality, network resource efficiency and processing overhead in IWU/CLS and the network, and have been mostly evaluated only for a single IWU model. This paper aims at showing the most appropriate method of LAN/MAN interworking for IWU-IWU or IWU-CLSF connection. In the paper, some interworking issues including a general qualitative assessment are clarified. We then evaluate the selected five interworking methods based on Bandwidth Renegotiation (BR) and VC Establishment (VCE), which are combined with Traffic Enforcement Functions (TEFs) based on policing mechanisms and Cell Loss Control (CLC) scheme. By transient and stationary simulation approach for a single IWU and an IWU-CLS connection model, the most applicable method is indicated as a case study from view points of the communication quality, effective use of the bandwidth and processing load.

There is a wide perception of the need for conformance and interoperability testing to ensure the interoperability of open systems. In the circumstances, we have been making efforts to establish a system for interconnectability testing, which is a type of the interoperability testing. In this paper, we discuss an interconnectability testing system, named AICTS (AIC's InterConnectability Testing System) that we have designed. We also discuss a conformance testing system, named ACTS (AIC Conformance Test System), which we developed as the first step toward building an interconnectability testing system. ACTS is capable of extensions for an interconnectability testing system.

In this letter, we propose a simple voltage controlled oscillator (VCO) with circuitry combining a Miller integrator and an RS flip-flop circuit. With the VCO, the control voltage can be varied over a broad range, and the oscillation frequency varies in proportion to the control voltage. The maximum voltage is up to 1000 times the minimum, and the calculated design values and measured values agree well. This VCO can be applied to FM modulators, FSK modulators, and other systems.

This paper describes, based on generation mechanism of conductive noise, that the real conductive noise on AC-mains can't be measured by LISN and 50 Ω-input impedance instrument specified by regulations such as CISPR. Second, it is pointed out that one of the causes of poor reproducibility in radiated emission measurement is the difference among line impedances of AC-mains. Finally, it is insisted that the apparatus such as LISN is necessary for stable measurement of radiated emission, and what improvement on LISN characteristics for higher frequency range should be done is introduced.

Damgrd defined the notion of a collision intractable hash functions and showed that there exists a collection of collision intractable hash functions if there exists a collection of claw-free permutation pairs. For a long time, the necessary and sufficient condition for the existence of a collection of collision intractable hash functions has not been known, however, very recently Russell finally showed that there exists a collection of collision intractable hash functions iff there exists a collection of claw-free pseudo-permutation pairs. In this paper, we show an alternative necessary and sufficient condition for the existence of a collection of collision intractable hash functions, i.e., there exists a collection of collision intractable hash functions iff there exists a collection of distinction intractable pseudo-permutations.

In this letter a new method for controlling chaos is proposed. Although different several methods based on the OGY- and the OPF-method perturb a value of an accessible system parameter, the proposed method perturbs the only timing of switching three values of a parameter. We apply the proposed method to the well-known Chua's circuit on computer simulations. The chaotic orbits in the Rössler type- and the double scroll type-attractor can be stabilized on several unstable periodic orbits embedded within these attractors.

Video compression technologies such as MPEG have enabled the efficient use of video data in the computer environment. However, the compressed video information still has a huge amount of data compared with the other media such as text, audio, and graphics. Therefore, it is very important to handle the video information in a networked database for the efficient use of resources like storage media. Furthermore, in the networked database, its retrieval methods including search and delivery become the key issues especially for the video information which requires a large network bandwidth. In this paper, a video browsing method using an automatic fast scene cut detection for networked video database access is described. The scene cut is defined as the scene change frame and is detected by temporal change in interframe luminance difference and chrominance correlation which are obtained from spatio-temporally scaled image directly extracted from the MPEG compressed video without any complex processing of video decoding. The detected scene change frames are further investigated to exploit the relationship between the scene cuts and are classified in order to make a hierarchical indexing. These results of detection are stored as an scene index file using the MPEG format. The simulation results are also presented for several test video sequences to show that these methods have enabled the efficient video database construction and accessing.

Technology mapping algorithms for LUT (Look Up Table) based FPGAs have been proposed to transfer a Boolean network into logic-blocks. However, since those algorithms take no layout information into account, they do not always lead to excellent results. In this paper, a simultaneous technology mapping, placement and global routing algorithm for FPGAs, Maple, is presented. Maple is an extended version of a simultaneous placement and global routing algorithm for FPGAs, which is based on recursive partition of layout regions and block sets. Maple inherits its basic process and executes the technology mapping simultaneously in each recursive process. Therefore, the mapping can be done with the placement and global routing information. Experimental results for some benchmark circuits demonstrate its efficiency and effectiveness.

A novel low-power dissipation and high-speed converter-control-IC has been developed for the transmitting amplifier in digital portable telephones. The IC consists mainly of CMOS devices to reduce the bias current. To improve circuit speed, bipolar transistors are used in the output stage of the operational amplifier and in the current sources of the oscillator because they have a larger current capability and smaller parasitic capacitance than CMOS devices. The IC has one-fifth the bias current of a conventional control circuit consisting of discrete devices, and it can operate up to a switching frequency of 3MHz. The small bias current increases converter efficiency, and the high switching frequency reduces converter size. Using this IC, converter loss is 17% less than that with a conventional control circuit.