We present a mechanism, named the law of the jungle (LOJ), to improve the Kohonen learning. The LOJ is used to be an adaptive vector quantizer for approximating nonstationary probability distribution functions. In the LOJ mechanism, the probability that each node wins in a competition is dynamically estimated during the learning. By using the estimated win probability, "strong" nodes are increased through creating new nodes near the nodes, and "weak" nodes are decreased through deleting themselves. A pair of creation and deletion is treated as an atomic operation. Therefore, the nodes which cannot win the competition are transferred directly from the region where inputs almost never occur to the region where inputs often occur. This direct "jump" of weak nodes provides rapid convergence. Moreover, the LOJ requires neither time-decaying parameters nor a special periodic adaptation. From the above reasons, the LOJ is suitable for quick approximation of nonstationary probability distribution functions. In comparison with some other Kohonen learning networks through experiments, only the LOJ can follow nonstationary probability distributions except for under high-noise environments.

Practical design procedure of a four-pole dual-mode cavity filter is explained in the details. Coupling matrix M of an elliptic function filter is derived analytically. The effects of septum thickness is studied experimentally. The dimensions of the aperture have to be modified due to the effects. This attempt had made the filter design very elegant, because no complicated calculation is required. A four-pole filter and a multiplexer are designed and constructed experimentally. They show very excellent performances in the 23 GHz band.

This paper describes a design and application method of multiple chip module (MCM) technology into microwave applications. An X-Band transmit and receive (T/R) module that has high volume production capability is described. The MMIC chip set designed to achieve multiple functions and state of the arts performance is also described. Peak performance between 8. 5 and 10. 5 GHz includes a power output of 8 W, a noise figure of 6 dB, 23 dB of receive and transmit gains, and a 5-bit phase shifter with less than 5. 5 degree rms phase error. The MCM based module utilizes advanced packaging technique, resulting in a highly integrated and mass production capability.

We propose an approach to obtain the relation between the number of voice call users and the number of data call users in the reverse link of a DS-CDMA cellular system with mixed rate traffic. The analyzed results show that as the number of data call users with high bit rate increases, the number of allowable voice call users decreases rapidly and linearly.

In land mobile communication, CMA (Constant Modulus Algorithm) has been studied to reduce multipath fading effect. By this method, the transmitted power is not used efficiently since all the multipath components have the same information. To make use of received power efficiently, we propose a Blind Multiple Beam Adaptive Array. It has the following three feature points. First, we use CMA which can reduce the multipath fading effect to some extent without training signal. Second, LMS algorithm which can capture the multipath components which are separated from the reference signal by some extent. Third, we use FDF (Fractional Delay Filter) and TED (Timing Error Detector) loop which can detect and compensate fractional delay. As a result of utilizing the multipath components which is suppressed by CMA, the proposed technique achieves better performance than CMA adaptive array.

This paper describes the design of a multistandard video encoder. The proposed encoder accepts conventional NTSC/PAL video signals. The encoder consists of four major building functions which are color space converter, digital filters, color modulator, and timing generator. In order to support multistandard video signals, a programmable systolic architecture is adopted in designing various digital filters. Interpolation digital filters are also used to enhance SNR of encoded video signals. The input to the encoder can be either YCbCr signal or RGB signal. The outputs are luminance (Y), chrominance (C), and composite video baseband (Y+C) signals. The architecture of the encoder is defined by using Matlab program and is modelled by using Verilog-HDL language. The overall operation is verified by using various video signals, such as color bar patterns, ramp signals, and so on. The encoder contains 36 k gates and is implemented by using 0. 65 µm CMOS process.

It is important to know phase offsets of a binary code in the field of mobile communications because different phase offsets of the same code are used to distinguish signals received at a mobile station from those of different base stations. When the period of the code is not very long, the relative phase offset between the code and its shifted code can be found by counting the number of bits delayed from the code of the same bit streams. But as the period of the code increases, it becomes difficult to find the phase offset. This paper proposes a new method to calculate the phase offset of a binary code. We define an accumulator function, which is used to calculate the phase offsets between the code and its shifted code. Also the properties of the accumulator function are investigated. This number theoretical approach and its results show that this method is very easy for the phase offset calculation. Its application to the code division multiple access (CDMA) system to define a reference code is given. The simple circuit realization of the accumulator function to calculate the phase offset between the received code and receiver stored replica code is described.

We present experimental results for a structural learning method of feed-forward neural-network classifiers using Principal Component Analysis (PCA) network and Species Genetic Algorithm (SGA). PCA network is used as a means for reducing the number of input units. SGA, a modified GA, is employed for selecting the proper number of hidden units and optimizing the connection links. Experimental results show that the proposed method is a useful tool for choosing an appropriate architecture for high dimensions.

We propose a Generalized Order Statistic Cell Averaging (GOSCA) CFAR detector. The weighted sums of the order statistics in the leading and lagging reference windows are utilized for the background level estimate. The estimate is obtained by averaging the weighted sums. By changing the weighting values, various CFAR detectors are obtained. The main advantage of the proposed GOSCA CFAR detector over the GOS CFAR detector is to reduce a computational time which is critical factor for the real time operation. We also derive unified formulas of the GOSCA CFAR detector under the noncoherent integration scheme. For Swerling target cases, performances of various CFAR detectors implemented using the GOSCA CFAR detector are derived and compared in homogeneous environment, and in the case of multiple targets and clutter edges situations.

A novel channel assignment scheme in DS-CDMA cellular systems is proposed, which overcomes the handoff interruptions of delay sensitive services by increasing the probability that soft handoff occurs in handoff for them. For that purpose, the priority of using the frequency channels served by all of cells is given to delay sensitive services over delay insensitive ones.

In live multimedia applications with multiple videos, it is necessary to develop an efficient mechanism of multiplexing several MPEG video streams into a single stream and transmitting it over network without wasting excessive bandwidth. In this paper, we present an efficient multiplexing and traffic smoothing scheme for multiple variable bit rate (VBR) MPEG video streams in live video applications with finite buffer sizes. First, we describe the constraints imposed by the allowable delay bound for each elementary stream and by the multiplexer/receiver buffer sizes. Based on these constraints, a new multiplexing and traffic smoothing scheme is designed in such a way as to smooth maximally the multiplexed transmission rate by exploiting temporal and spatial averaging effects, while avoiding the buffer overflow and underflow. Through computer experiments based on an MPEG-coded video trace of Star-wars, it is shown that the proposed scheme significantly reduces the peak rate, coefficient of variation, and effective bandwidth of the multiplexed transmission rate.

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.

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.

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.

The features for the integration of 1Tr/1C DRAM and logic for graphic and multimedia applications are surveyed. The key circuit/process technology for large scale embedded DRAM cores is described. The methods to improve transistor performance and gate density are shown. Noise immunity design and easy customization techniques are also introduced.

This paper introduces an error controlled decision feedback (ECDF) multiuser receiver, which integrates a successive canceller with linear block channel coding to mitigate decision error propagation. In particular, it uses a switching successive cancellation feedback loop, which can be open if excessive bit errors occur to prevent decision error propagation. The results of computer simulation show that the ECDF receiver possesses advantages in terms of near-far resistance and BER over many reported schemes.

Let G = (A, B, E) be a bipartite graph with bipartition (A:B) of vertex set and edge set E. For each vertex v, Γ(v) denotes the set of adjacent vertices to v. G is said to be t-convex on the vertex set A if there is a tree and a one-to-one correspondence between vertices in A and edges of the tree such that for each vertex b B the edges of the tree corresponding to vertices in Γ(b) form a path on the tree. G is doubly t-convex if it is convex both on vertex set A and on B. In this paper, we show that, the class of doubly t-convex graphs is exactly the class of bipartite circle graphs.

We propose a finite-capacity single-vacation model, with close-down/setup times and a Markovian arrival process (MAP), for SVC-based IP-over-ATM networks. This model considers the SVC processing overhead and the bursty nature of IP packet arrivals. Specifically, the setup time corresponds to the SVC setup time and the vacation time corresponds to the SVC release time, while the close-down time corresponds to the SVC timeout. The MAP is a versatile point process by which typical bursty arrival processes like the IPP (interrupted Poisson process) or the MMPP (Markov modulated Poisson process) is treated as a special case. The approach we take here is the supplementary variable technique. Compared with the embedded Markov chain approach, it is more straightforward to obtain the steady-state probabilities at an arbitrary instant and the practical performance measures such as packet loss probability, packet delay time, and SVC setup rate. For the purpose of optimal design of the SVC-based IP-over-ATM networks, we also propose and derive a new performance measure called the SVC utilization ratio. Numerical results show the sensitivity of these performance measures to the SVC timeout period as well as to the burstiness of the input process.

We propose a new approach to the exact performance analysis of a shared buffer ATM multiplexer, which is loaded with mixed correlated and uncorrelated traffic sources. We obtain the joint steady-state probabilities of both states of the input process and the buffer using a one-dimensional Markov chain. From these probabilities we calculate the loss probabilities and the average delays of the correlated and the uncorrelated traffic sources.

This paper proposes polling-based real-time software for MPEG2 System protocol LSIs, which is a typical embedded and real-time system on a chip, and demonstrates its performance and usefulness. The polling-based real-time software is designed and optimized by analyzing application specific function requirements and deciding scheduling intervals and the execution cycles of each task. It requires neither hardware for multiple interrupt handling nor software for heavy context switching. The polling-based approach provides sufficient performance without any hardware and software overhead for a real-time application like the MPEG2 System protocol.