Analysis of frequency-dependent lossy transmission lines is very important for designing the high-speed VLSI, MCM and PCB. The frequency-dependent parameters are always obtained as tabulated data. In this paper, a new curve fitting technique of the tabulated data for the moment matching technique in the interconnect analysis is presented. This method based on Chebyshev interpolation enhances the efficiency of the moment matching technique.

This paper proposes a new flexible hardware model for pipelined design optimization. Using together with an RTL floorplanner, the flexible hardware model makes accurate and fine design space exploration possible. It is quite effective for deep submicron technology since estimation at high level has become a difficult problem and the design tuning at lower level of abstraction makes up the full design optimization task. The experimental results show that our approach reduces the slack time in the pipeline stages then achieves higher performance with a smaller area.

This paper proposes a high-level synthesis system for datapath design of digital processing hardwares. The system consists of four phases: (1) DFG (data-flow graph) generation, (2) scheduling, (3) resource binding, and (4) HDL (hardware description language) generation. In (1), the system does not generate only one best DFG representing a given behavioral description of a hardware, but more than one good DFGs representing it. In (2) and (3), several synthesis tools can be incorporated into the system depending on the required objectives. Thus we can obtain more than one datapath candidates for a behavioral description with their area and performance evaluation. In (4), the best datapath design is selected among those candidates and its hardware description is generated. The experimental results for applying the system to several benchmarks show the effectiveness and efficiency.

The importance of technology retargeting for hard IPs is getting increased. However, recent advances in process technologies make layout reuse too complicated to be done by conventional compactors. As an efficient approach, this paper proposes a flexible layout abstraction model and a new layout synthesis algorithm. The synthesis algorithm provides a concurrent procedure of detailed wiring, compaction, and transistor layout generation by using a scan line to get better layout results than conventional compactors. We have applied this method to the technology retargeting of actual cell layouts and have achieved quite good results comparable to hand-crafted designs.

Network traffic contains many symptoms of various network faults. Symptoms of faults aggregate and are manifested in the aggregate traffic characteristics generally observed by a traffic monitor. It is very difficult for a manager or an NMS (Network Management Station) to isolate the symptoms manifested in the aggregate traffic characteristics. Especially, transit networks, like a backbone network, deal with many types of traffic. So, symptom isolation must be efficient. In this paper, we propose a powerful algorithm for symptom isolation. This algorithm is based on the popular SNMP-based RMON technology. Using dynamically constructed aggregate, fresh symptoms can be isolated efficiently. We apply the algorithm to two operational transit networks which connects some LANs and WANs, and evaluate it using trace data collected from these networks. The results show a significant improvement in the fault management capability and accuracy. Furthermore, the characteristics of fault symptoms and the various factors for effective system configuration are discussed.

A Pragmatic Trellis Coded MPSK on a Rayleigh fading channel is analyzed. This scheme allows bandwidth expansion ratio to be varied aiming at an optimization between complexity of the system design and improvement of coding gain. In order to vary the bandwidth expansion ratio, a punctured convolutional code is used. The performance of the proposed TC-2mPSK on a Rayleigh fading channel is theoretically analyzed. In the test examples, the BER performances of TC-QPSK and TC-8PSK are evaluated by theoretical analyses and computer simulations at the encoder parameters of K3 and r3/4. The results show that the proposed scheme can attain better performance not only over the uncoded scheme but over the conventional Pragmatic TCM.

A fuel cell energy system is under development for supply of generated electrical energy to telecommunications equipment. It is a cogeneration system; the heat energy recovered is used to cool the telecommunications equipment. For this system, a method is described for controlling a new DC interconnection converter. Its DC interconnection characteristics are also discussed. The new converter controls its input current to the fuel cell rated current at maximum and can operate stably even when the fuel cell voltage decreases. This allows good DC interconnection characteristics to be obtained in both the steady state and the transient state.

The project of interconnecting CATV in Hyogo Prefecture, Japan has started since March, 1998. In this project, there are three CATV companies in Hanshin area; Kobe, Nishinomiya and Amagasaki. An ATM switch is equipped in each company and these CATVs are connected serially in the above order. Each company provides the video service to the rest of companies using the MPEG2 over ATM. Each MPEG2 stream is sent to the other two CATV companies according to the function of multicast implemented in ATM switch. In the coverage of each CATV, subscribers utilize Internet connection using cable modems as well as standard CATV broadcasting service. In this paper, we present the outline of the research project in Hyogo Prefecture, Japan, and examine the jitter processes of MPEG streams of the testbed network by the simulation. In our testbed network, cells with two types of requirement for QoS are multiplexed; cells for MPEG2 which require the real-time transmission and those for Internet packets which are much more sensitive for the cell loss ratio. We investigate the jitter processes under some scenarios and show how the jitter process is affected by the Internet traffic and the other cell streams of MPEG2. Furthermore, we study the effect of the number of ATM switches on the jitter process when more CATV networks are added serially.

The recently proposed modified PML (MPML) absorbing boundary condition is extended to three dimensions. The performance of the MPML is investigated by FDTD simulation of a typical microstrip line and a rectangular waveguide. The dominant and higher order modes of the microstrip line and the waveguide are excited separately in the computation. In all of the cases of excitation, the reflection properties of the MPML boundaries are examined for the side walls and the end walls, respectively. Various values of the permittivity and permeability of the MPML medium are tested in the computation, and the variation behavior of reflection from the MPML boundaries is examined. The numerical results reveal that by choosing appropriate values of the permittivity and permeability of the MPML, we can realize efficient absorption of both evanescent waves and propagating waves over a wide frequency band.

This paper presents a new efficient method for finding an "optimal" bi-decomposition form of a logic function. A bi-decomposition form of a logic function is the form: f(X) = α(g1(X1), g2(X2)). We call a bi-decomposition form optimal when the total number of variables in X1 and X2 is the smallest among all bi-decomposition forms of f. This meaning of optimal is adequate especially for the synthesis of LUT (Look-Up Table) networks where the number of function inputs is important for the implementation. In our method, we consider only two bi-decomposition forms; (g1 g2) and (g1 g2). We can easily find all the other types of bi-decomposition forms from the above two decomposition forms. Our method efficiently finds one of the existing optimal bi-decomposition forms based on a branch-and-bound algorithm. Moreover, our method can also decompose incompletely specified functions. Experimental results show that we can construct better networks by using optimal bi-decompositions than by using conventional decompositions.

In this paper, we consider the applicability of turbo code for future third generation (3G) mobile telecommunication systems. Futhermore, we propose a simple method of estimating the channel variance which is necessary for the MAP (Maximum A Posteriori) decoding algorithm. We compare the performance of turbo code with a known channel variance, conventional variance estimate and variance estimated by our proposed technique. We show that our variance estimation scheme is adequate for 3G WB-CDMA mobile systems without degradation of turbo code performance.

Gd2O2S:Tb phosphor thin films have been prepared using the simple technique of electron beam evaporation for large area display applications. The photoluminescence and excitation spectra measurement of Gd2O2S:Tb phosphor thin films suggest that Tb3+ is incorporated into the Gd2O2S lattice at gadolinium sites. Relatively efficient electroluminescence is observed from a ZnS/Gd2O2S:Tb/ZnS sandwich cell.

A 14. 4-in. diagonal EL display with 640128 pixels has been developed in red/green multicolor structures by using a new phosphor layer consisting of Zn1-xMgxS:Mn and ZnS:Mn. The display is designed for 240 Hz-frame rate, enabling the luminance to be improved by a factor of two. In addition, the contrast ratio is strongly enhanced by optimizing the black background structure and color filters. Improved characteristics make it possible for the EL panel to meet the requirements for the public information display taking advantages of high-reliability, crisp image and wide-viewing angle. Furthermore, the possibility of full-color EL displays will be described on the basis of "color by white" approach.

We discuss optimal rotation estimation from two sets of 3-D points in the presence of anisotropic and inhomogeneous noise. We first present a theoretical accuracy bound and then give a method that attains that bound, which can be viewed as describing the reliability of the solution. We also show that an efficient computational scheme can be obtained by using quaternions and applying renormalization. Using real stereo images for 3-D reconstruction, we demonstrate that our method is superior to the least-squares method and confirm the theoretical predictions of our theory by applying bootstrap procedure.

In a shared-memory multiprocessor, shared data are usually accessed in a critical section that is protected by a lock variable. Therefore, the order of accesses by multiple processors to the shared data corresponds to the order of acquiring the ownership of the lock variable. This paper presents a selective write-update protocol, where data modified in a critical section are stored in a write cache and, at a synchronization point, they are transferred only to the processor that will execute the critical section following the current processor. By using QOLB synchronization primitives, the next processor can be determined at the execution time. We prove that the selective write-update protocol ensures data coherency of parallel programs that comply with release consistency, and evaluate the performance of the protocol by analytical modeling and program-driven simulation. The simulation results show that our protocol can reduce the number of coherence misses in a critical section while avoiding the multicast of write-update requests on an interconnection network. In addition, we observe that synchronization latency can be decreased by reducing both the execution time of a critical section and the number of write-update requests. From the simulation results, it is shown that our protocol provides better performance than a write-invalidate protocol and a write-update protocol as the number of processors increases.

Because of non-negligible ISI due to the Gaussian filter and delay spread in the GSM system, an equalizer is required. In this letter, a joint sliding window channel estimation and timing adjustment method is proposed for maximum likelihood sequence equalizer. And also a smoothing algorithm is presented in order to improve the equalizer performance. This smoothing scheme utilizes a variant of LMS algorithm to tune the channel coefficient estimates. Simulation results show that the proposed scheme is adequate for channel estimation of the adaptive equalizer.

As the current Internet becomes popular in information access, demands for real-time display and playback of continuous media are ever increasing. The applications include real-time audio/video clips embedded in WWW, electronic commerce, and video-on-demand. In this paper, we present a new control protocol R3CP for real-time applications that transmit stored MPEG video stream over a lossy and best-effort based network environment like the Internet. Several control mechanisms are used: a) packet framing based on the meta data; b) adaptive queue-length based rate control scheme; c) data preloading; and d) look-ahead pre-retransmission for lost packet recovery. Different from many adaptive rate control schemes proposed in the past, the proposed flow control is to ensure continuous, periodic playback of video frames by keeping the receiver buffer queue length at a target value to minimize the probability that player finds an empty buffer. Contrary to the widespread belief that "Retransmission of lost packets is unnecessary for real-time applications," we show the effective use of combining look-ahead pre-retransmission control with proper data preloading and adaptive rate control scheme to improve the real-time playback performance. The performance of the proposed protocol is studied via simulation using actual video traces and actual delay traces collected from the Internet. The simulation results show that R3CP can significantly improve frame playback performance especially for transmission paths with poor packet delivery condition.

Network survivability against various unexpected failures is one of indispensable technologies for the B-ISDN infrastructure. Self-healing algorithm is the technique to automatically restore the failed VP's (virtual paths) in the backbone ATM network. Since the B-ISDN transports various kinds of traffic with various levels of priority (Grade of Service: GoS), the effective self-healing algorithm should orderly restore the failed VP's based on the priority of their traversing traffic. This paper proposes the priority based restoring self-healing algorithm, which realizes the priority based restoring function by the two-timer mechanisms and a simple capacity reserving protocol. The simulation results show that the proposed algorithm can schedule the restoration process so that the failed VP's with higher priority are restored before the others with lower priority. In addition, the significant improvement in restoration speed for the highest priority traffic class has been achieved.

In order to enhance the energy transfer efficiency in a Cherenkov laser, we propose to use a tapered waveguide with a dielectric thickness properly varied stepwise in the longitudinal direction. With the aid of particle simulation, we investigate the nonlinear characteristics of the Cherenkov laser with the tapered waveguide, demonstrating the effectiveness of our proposal for efficiency enhancement.

This paper describes a factorization-based algorithm that reconstructs 3D object structure as well as motion from a set of multiple uncalibrated perspective images. The factorization method introduced by Tomasi-Kanade is believed to be applicable under the assumption of linear approximations of imaging system. In this paper we describe that the method can be extended to the case of truly perspective images if projective depths are recovered. We established this fact by interpreting their purely mathematical theory in terms of the projective geometry of the imaging system and thereby, giving physical meanings to the parameters involved. We also provide a method to recover them using the fundamental matrices and epipoles estimated from pairs of images in the image set. Our method is applicable for general cases where the images are not taken by a single moving camera but by different cameras having individual camera parameters. The experimental results clearly demonstrates the feasibility of the proposed method.