This paper presents an evolutionary scheduling scheme for solving the job shop scheduling problem (JSSP) and other combinatorial optimization problems. The approach is based on a genetized-knowledge genetic algorithm (gkGA). The basic idea behind the gkGA is that knowledge of heuristics which are used in the GA is also encoded as genes alongside the genetic strings, referred to as chromosomes. Furthermore, during the GA selection, weaker heuristics die out while stronger ones survive for a given problem instance. We evaluate our evolutionary scheduling scheme based on the gkGA approach using well known benchmark instances for the JSSP. We observe that the gkGA based scheme is shown to consistently outperform the scheme based on ordinary GAs. In addition the gkGA-based scheme removes the problem of instance dependency.

In this paper, we present several traffic handling schemes for improving the QoSs (quality-of-services) in a micro-cell based PCS (personal communication services) network. Traffic handling schemes are devised for the efficient use of the limited radio resources with the increasing number of users and multimedia traffic. Both mathematical analysis and computer simulations are carried out for the performance evaluation in terms of the blocking probability of new call, the forced termination probability of handoff voice and data and the average delay of data. Analytical models by bivariate Markov processes are provided. It reveals that a finite queueing scheme for handoff delay sensitive data guarantees QoS metrics, such as the blocking probability of new voice and data and forced termination probability of handoff voice and data, as well as the efficient use of radio resources. The optimal number of reserved channels for handoff delay sensitive data and the optimal number of reserved channels for handoff traffic (in reserved channel scheme) are investigated and obtained. Dynamically controlled reserved channel schemes turn out to provide no significant performance improvement.

In this paper, an FPGA (Field Programmable Gate Array)-implementable digital chaos circuit with nonlinear mapping function learning ablility is proposed. The features of this circuit are user-programmability of the mapping functions by on-chip supervised learning, robustness of chaos signal generation based on digital processing, and high-speed and low-cost thanks to its FPGA implementation. The circuit design and analysis are presented in detail. The learning dynamics of the circuit and the quantitization effect to the quasi-chaos generation are analyzed by numerical simulations. The proposed circuit is designed by using an FPGA CAD tool, Verilog-HDL. This confirmed that the one-dimensional chaos circuit block (except for SRAM's) is implementable on a single FPGA chip and can generate quasi-chaos signals in real time.

A new approach for the flow control of available bit rate service in ATM network is proposed using supervisory control theory upon discrete event models. According to the approach, each rate controller adjusts the input source traffic within a specific zone decided by the supervisor. In this way, the proposed control scheme ensures congestion avoidance and the maximal successful transmission rate of the input source traffic in a fair manner upon a simplistic way of explicit rate setting for resource management cells.

The purpose of this letter is to investigate the stability conditions of the active two port networks having some restrictions on load and source terminations, and then they have been obtained. Next, these results and the previous stability coditions are investigated, and then the new combined stability condition are proposed.

This paper is concerned with Wiener-Hopf solutions to the electromagnetic wave scattering by a conducting finite thin plate when the incident wave is not a plane wave. The incident wave is approximated in terms of a piece-wise plane wave on a divided small section of the conducting plate. The final expressions are given in an analytically compact form and the results are accurate as long as the plate width is greater than the wavelength and the divided section is so small that we can expand the incident wave by a piece-wise plane wave. A criterion for the ray tracing method is also proposed.

A multimedia coding standard, MPEG4 has frozen its Committee Draft (CD) as the MPEG4 version 1 CD, last October. It defines Audio-Visual (AV) coding Algorithms and their System Multiplex/Composition formats. Founding on Object-base concept, Video part adopts Shape Coding technology in addition to conventional Texture Coding skills. Audio part consists of voice coding tools (HVXC and CELP core) and audio coding tools (HILN and MPEG2 AAC or Twin VQ). Error resilience technologies and Synthetic and Natural Hybrid Coding (SNHC) technologies are the MPEG4 specific features. System part defines flexible Multiplexing of audio-visual bitstreams and Scene Composition for user-interactive re-construction of the scenes at decoder side. The version 1 standardization will be finalized in 1998, with some possible minute changes. The expected application areas are real-time communication, mobile multimedia, internet/intranet accessing, broadcasting, storage media, surveillance, and so on.

In this paper, we propose a descriptor as a shape signature and the projective refinement as a verification method for recognizing 2D curved objects with occlusions from their partial views. For an extracted curve segment, we compute a series of the geometric invariance of equally spaced five co-planar points on the curve. Thus the resulting descriptor is invariant only under rotation, translation, and scale, but sufficient similarity is preserved even under large distortions. It is more stable and robust since it does not need derivatives. We use this transformation-invariant descriptor to index a hash table. We show the efficiency of the method through experiments using seriously distorted images of 2-D curved objects with occlusions.

Weighted Round Robin (WRR) scheduling is an extension of round robin scheduling. Because of its simplicity and bandwidth guarantee, WRR cell scheduling is commonly used in ATM switches. However, since cells in individual queues are sent cyclically, the delay bounds in WRR scheduling grow as the number of queues increases. Thus, static priority scheduling is often used with WRR to improve the delay bounds of real-time queues. In this paper, we show that the burstiness generated in the network is an even greater factor affecting the degradation of delay bounds. In ATM switches with per-class queueing, a number of connections are multiplexed into one class-queue. The multiplexed traffic will have a burstiness even if each connection has no burstiness, and when the multiplexed traffic is separated at the down stream switches, the separated traffic will have a burstiness even if the multiplexed traffic has been shaped in the upstream switches. In this paper, we propose a new WRR scheme, namely, WRR with Save and Borrow (WRR/SB), that helps improving the delay bound performance of WRR by taking into account the burstiness generated in the network. We analyze these cell scheduling methods to discuss their delay characteristics. Through some numerical examples, we show that delay bounds in WRR are mainly dominated by the burstiness of input traffic and, thus WRR/SP, which is a combination of WRR and static priority scheduling, is less effective in improving delay bounds. We show that WRR/SB can provide better delay bounds than WRR and that it can achieve the same target delay bound with a smaller extra bandwidth, while large extra bandwidth must be allocated for WRR.

This paper presents an efficient bandwidth allocation method for the two-layer video coding of different spatial resolution. We first find a model of distortion-bitrate relationship for the MPEG-2 spatial scalable coding in a fixed total bitrate system. Then we propose an adaptive bitrate allocation method for a constant distortion ratio between two layers with the given total bandwidth. In the proposed method, approximated model parameters are used for simple implementation. The validity of the approximation is proven in terms of the convergence to the desired distortion ratio. It is shown by simulation that the proposed bitrate allocation method can keep almost a constant distortion ratio between two layers in comparison to a fixed bitrate allocation method.

We have developed a low bit-rate video coding using a video digital signal processor (DSP) called VDSP1χ, which performs real-time encoding and decoding for discrete cosine transform-(DCT-) based algorithms, such as ITU-T H. 261, H. 263 and wavelet-based subband encoding algorithms. This LSI features a processing unit which implements wavelet filters at high speeds, a compact DCT circuit, and a fast, flexible DRAM interface for low-cost systems. This system is capable of processing quarter common intermediate format (QCIF)(176144 pixels) size pictures at a rate greater than 15 frames/s.

We have proposed a non-invasive method for diagnosis of the early stage of atherosclerosis, namely, the detection of small vibrations on the aortic wall near the heart by using ultrasound diagnostic equipment. It is, however, necessary to confirm the effectiveness of such measurement of the pulse wave velocity for quantitative evaluation of the local characteristics of atherosclerosis. It is well known that Young's modulus of a tube wall, estimated from measured pulse wave velocity, depends on inner pressure because of the non-linear relationship between the inner pressure and the change of volume in the tube. The inner pressure, however, changes during the period of one heartbeat. In this experimental study, we found for the first time that Young's modulus of the tube wall, estimated from the measured pulse wave velocity, depends not only on the diastolic pressure but also on the pulse pressure and the pressure gradient of the systolic period.

This paper addresses the optimum routing problem of multipoint connection in large-scale networks. A number of algorithms for routing of multipoint connection have been studied so far, most of them, however, assume the availability of complete network information. Herein, we study the problem under the condition that only partial information is available to routing nodes and that routing decision is carried out in a distributed cooperative manner. We consider the network being partitioned into clusters and propose a cluster-based routing approach for multipoint connection. Some basic principles for network clustering are discussed first. Next, the original multipoint routing problem is defined and is divided into two types of subproblems. The global optimum multicast tree then can be obtained asymptotically by solving the subproblems one after another iteratively. We propose an algorithm and evaluate it with computer simulations. By measuring the running time of the algorithm and the optimality of resultant multicast tree, we show analysis on the convergent property with varying network cluster sizes, multicast group sizes and network sizes. The presented approach has two main characteristics, 1) it can yield asymptotical optimum solutions for the routing of multipoint connection, and 2) the routing decisions can be made in the environment where only partial information is available to routing nodes.

We present techniques to implement fair-sharing on both link bandwidth and buffer space in a switch or router. Together they possess the following merits: 1. solving the counter-overflow problem; 2. avoiding the "credit" accumulation issue; 3. integrating bandwidth allocation with buffer management. The simplicity of this method makes it a viable candidate for implementational use on switches and routers.

Cell delay variation (CDV) has been considered as an important performance measure due to the stringent timing requirement for video and multimedia services. In this paper we address the problem of CDV performance guarantee in virtual path (VP)-based ATM multiplexing. We propose a rate-based and non-work-conserving scheduling algorithm, called interleaved round robin (IRR), for serving traffic streams among VPs into the outgoing link. Through our performance analysis, the proposed scheme is capable of providing upper and lower bounds on the inter-visit time (IVT) for each VP, where the difference between the upper bound and the lower bound is simply dependent upon the number of multiplexed VPs. The distribution of VP IVT scheduled by an IRR server can also be well approximated using a random incidence technique. In addition to the VP-level CDV performance, we further examine the virtual connection (VC)-level CDV incurred within a multi-stage network through simulation study. The simulation results show that the IRR server can provide traffic regulation and smoothness at each network node. Moreover, the CDV distribution of a tagged VC is insensitive to the source traffic characteristic, node location, and the hop count traversed in the network.

This paper deals with overload control during congestion in a shared buffer ATM switch via selective cell discard and buffer management. Specifically, we consider the question of efficiency in buffer control schemes in order to reduce the number of cells that have to be discarded during congestion, in the meantime provide "fair" access to the shared buffer by all users. To prevent performance degradation of the shared buffer switch under imbalance traffic conditions, a "gated" buffer control scheme is proposed. The concept of the "gated" control policy is that we add a control gate in front of the corresponding logical queue of each overloaded output port. Some incoming cells destined for the overloaded ports can be blocked before entering the shared buffer. It will make rooms in the shared buffer for those incoming cells destined for the non-overloaded ports. This gated buffer control scheme can be modeled as a variation of SMXQ (sharing with a maximum queue length) scheme with a set of dynamically adjusted queue length thresholds. The simulation study of the gated buffer control is applied to a shared buffer ATM switch under various cell discard mechanisms. In most cases the proposed gated buffer control scheme can not only reduce the overall cell loss but also satisfy the "fair" access requirement under network congestion conditions, if we adjust the dynamical queue length thresholds properly.

This paper describes two attacks against blind decryption (decode) based on the commutative random-self reducibility and RSA systems utilizing the transformability of digital signatures proposed in [2]. The transformable digital signature was introduced in [2],[8] for defeating an oracle attack, where the decrypter could be abused as an oracle to release useful information for an attacker acting as a requester of blind decryption. It was believed in [2],[8] that the correctness of a query to an oracle was ensured by the transformable signature derived from an original signature issued by the decrypter in advance, and a malicious query to an oracle could be detected before the blind decryption by the decrypter or would lead to release no useful information to an attacker. The first attack can decrypt all encrypted data with one access to an oracle. The second one generates a valid signature for an arbitrary message selected by an attacker abusing the validation check procedure.

We propose a set of new algorithms for linear programming. These algorithms are derived by accelerating the method of averaged convex projections for linear inequalities. We provide strict proofs for the convergence of our algorithms. The algorithms are so simple that they can be calculated by super-parallel processing. To this effect, we propose networks for implementing the algorithms. Furthermore, we provide illustrative examples to demonstrate the capability of our algorithms.

Antidiffusion is a process running the diffusion equation reversely in the time domain. Though extremely important for image restoration of the Gaussian blur, it is a horribly ill-posed problem, since minor noise leads to very erroneous results. To solve this ill-posed problem stably, in this paper we first apply a multiscale method to decompose images into various scale components using the Gaussian and Laplacian of Gaussian (LOG) filters. We then show that the restored images can be reconstructed from the components using shrunk Gaussian and LOG filters. Our algorithm has a closed form solution, and is robust to noise because it is performed by the integration computation (convolution), contrasting with the differential computation required by direct discretization of the antidiffusion equation. The antidiffusion algorithm is also computationally efficient since the convolution is row and column separable. Finally, a comparison between the algorithm and the well-known Wiener filter is conducted. Experiments show that our algorithm is really stable and images can be restored satisfactorily.

A new numerical approach for the analysis of electromagnetic scattering from a body moving in an arbitrary direction is described. A time dependent grid generation is applied to solve these problems. We are treating this method for a quasi-stationary field. Some numerical results are compared with the exact ones and excellent agreement between them is obtained.