In this paper, we propose a new denoising algorithm based on the dyadic wavelet transform (DWT) for ECG signals corrupted with different types of synthesized noise. Using the property that DWT is overcomplete, we define some convex sets in the set of wavelet coefficients and give an iterative method of the projection on the convex sets. The results show that the noises are not only removed from ECG signals, but also the ECG signals are reconstructed, which is used in detecting QRS complex. The performance of the proposed algorithm is demonstrated by some experiments in comparison with the conventional methods.

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.

This paper proposes a novel bidirectional rod antenna (BIRA) comprising a collinear antenna and parasitic wires as a base station antenna for a street microcell. The spacing between the collinear antenna and the parasitic wire, and the length of the parasitic wires, which are the design parameters obtaining a bidirectional pattern, are investigated using the moment method. The results show that wide spacing enlarges the bandwidth obtaining the bidirectional pattern, however it decreases the gain. Furthermore, to enlarge the bandwidth, a BIRA with arc parasitic plates whose radius is the same as that of the radome is also proposed. The configuration can be constructed using the same exterior as the BIRA with parasitic wires. It is also shown that the arc parasitic plates enlarge the bandwidth in proportion to the area projected onto the tangential plane at the center of the arc. Finally, a prototype of the proposed antenna is shown.

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.

In the wireless ATM network, the key issue is to guarantee various QoS (Quality of Service) under the conditions of the limited radio link bandwidth and error prone characteristics. In this paper, we show a combination method of the error correction schemes, which is suitable to establish multimedia wireless ATM Networks while keeping an efficient use of the limited bandwidth. We consider two levels of FEC; a bit-level and a cell-level to guarantee cell loss probabilities of real time applications. By combining two levels of FEC, various requirements on cell loss can be met. We then apply the bit-level FEC and ARQ protocol for the data communication; tolerant to the delay characteristics. Through the analytical methods, the required overheads of FECs are examined to satisfy the various QoS requirements of CBR connections. The mean delay analysis for the UBR service class is also presented. In numerical examples, we show how the combination scheme to guarantee various cell loss requirements affects the call blocking probability of the CBR service class and the delay of UBR service class.

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.

Huet and Levy showed that index reduction is a normalizing strategy for every orthogonal strongly sequential term rewriting system. Toyama extended this result to root balanced joinable strongly sequential systems. In this paper, we present a class including all root balanced joinable strongly sequential systems and show that index reduction is normalizing for this class. We also propose a class of left-linear (possibly overlapping) NV-sequential systems having a normalizing strategy.

In recent years, there has been a rapid growth in applications such as World Wide Web browsing, which are characterized by fairly short sessions that transfer substantial amounts of data. Conventional connection-oriented and datagram services are not ideally engineered to handle this kind of traffic. We present a new ATM service, called Dynaflow service, in which virtual circuits are created on a burst-by-burst basis and we evaluate key aspects of its performance. We compare Dynaflow to the Fast reservation protocol (FRP) and show that Dynaflow can achieve higher overall throughput due to the elimination of reservation delays, and through the use of shared "burst-stores. " We study the queueing performance of the dynaflow switch and quantify the relationship between the loss ratio and the buffer size.

In this paper, we propose a new lemma facility, called the strong contraction rule, for model elimination calculus, and we study some implementation issues of strong contraction in a PTTP-based theorem prover. Strong contraction has the ability to shorten possible proofs and prevent some irrelevant computation to a target goal. Strong contraction never broadens the search space, in principle, and thus, has a stable effect on the acceleration of top-down proof search. However, it is difficult to embed the strong contraction into a PTTP-based theorem prover, because strong contraction imposes a truncation operation of center chains in model elimination calculus. We show a self-truncation-style Prolog code, which makes it possible to retain the high performance of a PTTP-based prover with strong contraction. Finally, we evaluate the performance and effect of strong contraction by performing some experiments.

Presently, mobile robots are navigated by means of a number of methods, using navigating systems such as the sonar-sensing system or the visual-sensing system. These systems each have their strengths and weaknesses. For example, although the visual system enables a rich input of data from the surrounding environment, allowing an accurate perception of the area, processing of the images invariably takes time. The sonar system, on the other hand, though quicker in response, is limited in terms of quality, accuracy and range of data. Therefore, any navigation methods that involves only any one system as the primary source for navigation, will result in the incompetency of the robot to navigate efficiently in a foreign, slightly-more-complicated-than-usual surrounding. Of course, this is not acceptable if robots are to work harmoniously with humans in a normal office/laboratory environment. Thus, to fully utilise the strengths of both the sonar and visual sensing systems, this paper proposes a fusion of navigating methods involving both the sonar and visual systems as primary sources to produce a fast, efficient and reliable obstacle-avoiding and navigating system. Furthermore, to further enhance a better perception of the surroundings and to improve the navigation capabilities of the mobile robot, active sensing modules are also included. The result is an active sensor fusion system for the collision avoiding behaviour of mobile robots. This behaviour can then be incorporated into other purposive behaviours (eg. Goal Seeking, Path Finding, etc. ). The validity of this system is also shown in real robot experiments.

In recent years, the rapid advancements of wireless communication technology and computer down-sizing technology have enabled users to utilize computing resources anywhere in the computer network. New applications constructed on the mobile database system are becoming popular. However, the current database systems do not provide special facilities for specific update operations in a mobile computing environment. Moreover, due to the lack of a common data handling method and a mutual communication mechanism, varieties in implementations may cause applications to be incompatible with each other. In this paper, we take up the issue of data handling, in a mobile computing environment, and propose an active mobile database system (AMDS) to solve this issue. First, we review the difficulties of dynamic update of databases in a mobile computing environment, and provide a basic concept of AMDS as a solution for these difficulties. In order to construct an AMDS, we focus on asynchronous events such as the appearance and disappearance of a mobile computer in a wireless communication cell. Then we provide a facility to specify the behavior of each system in Event-Condition-Action(ECA) rules in the same way as normal active database systems. Moreover, we show the architecture and the design of our implementation of AMDS. And, finally AMDS can be easily implemented as a common database infrastructure and work well on heterogeneous systems through indoor experiments.

This paper investigates the relations between the computational complexity and the restrictions for several problems that determine whether a given graph with edge costs and edge lengths has a spanning subgraph with such restrictions as the diameter, the connectivity, and the NA-distance and the NA-(edge)-connectivity proposed and investigated in [1]-[5]. The NA-distance and the NA-(edge)-connectivity are the measures for the distance and the connectivity between a vertex and a vertex subset (area). In this paper we prove that the minimum diameter spanning subgraph problem considering the restrictions of the diameter and the sum of edge costs is NP-complete even if the following restrictions are satisfied: all edge costs and all edge lengths are equal to one, and the upper bound of the diameter is restricted to four. Next, we prove that the minimum NA-distance spanning subgraph problem considering the restrictions of the NA-distances and the sum of edge costs is NP-complete even if the following conditions are satisfied: all edge costs and all edge lengths are equal to one, the upper bound of the NA-distance is restricted to four, each area is composed of a vertex, and the number of areas is restricted to two. Finally, we investigate the preserving NA-distance and NA-edge-connectivity spanning subgraph problem considering the preservations of the NA-distances and the NA-edge-connectivity and the restrictions of the sum of edge costs, and prove that a sparse spanning subgraph can be constructed in polynomial time if all edge costs are equal to one.

In this paper, a new simulation approach to the analysis of the reflection characteristics on nonuniform transmission lines (NTLs) is presented. The input and output responses in the time domain and the reflection coefficients in the frequency domain are effectively obtained by using the modified central difference (MCD) simulation and the fast Fourier transform (FFT) technique for Gaussian pulse responses. The simulated results for the reflection characteristics of the NTL transformers are in excellent agreements with the theoretical values. By representing both the reflected voltage and the reflection coefficient, it is shown that this approach is useful to analyze for various types of tapered and stepped NTLs.

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.

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.

In the future, more and more network providers will be established through the introduction of an open telecommunications market. At this time, it is necessary to guarantee the fair competition between these network providers. In this paper, a negotiation protocol for connection establishment is proposed. This negotiation protocol is based on the concept of open, competitive bidding and can guarantee fair competition between the network providers. In this negotiation protocol, each network providers objective is to maximize its profit. Conversely, each users objective is to select a network provider which will supply as much capacity as required. Employing this negotiation protocol, the users and the network providers can select each other based on their objectives. In this paper, adaptation strategies which network providers and users can adopt under the proposed negotiation protocol framework are also discussed. A network provider which adopts this strategy can obtain enough profit even when the number of connection requests is small relative to the idle bandwidth capacity. Moreover, a user who adopts this strategy can be sure to obtain bandwidth even when the idle bandwidth capacity is small relative to the number of connection requests.

We examine the effectiveness of shaping and policing mechanisms in reducing the inherent variability of fractal traffic, with the objective of increasing network operating points. Whether a shaper simply spaces a flow or allows small bursts according to a leaky bucket, we show using analytical arguments that, i) the Hurst parameter, which describes the asymptotic variability of the traffic, is unaffected; and ii) while the traffic can be made smoother over time scales smaller than one corresponding to the shapers buffer size, fluctuations over longer time scales cannot be appreciably altered. We further show that if shaping is used to reduce buffer size requirements at a network bottleneck, any savings here are offset by the increased buffer requirements at the shapers. Perhaps the most significant deficiency of shaping identified here is that it is necessary to model individual streams to a level of accuracy that is not feasible in practice. In contrast, statistical multiplexing can achieve reasonable network efficiencies by only requiring characterizations of aggregate traffic.

For a given N-vertex graph H, a graph G obtained from H by adding t vertices and some edges is called a t-FT (t-fault-tolerant) graph for H if even after deleting any t vertices from G, the remaining graph contains H as a subgraph. For the n-dimensional cube Q(n) with N vertices, a t-FT graph with an optimal number O(tN+t2) of added edges and maximum degree of O(N+t), and a t-FT graph with O(tNlog N) added edges and maximum degree of O(tlog N) have been known. In this paper, we introduce some t-FT graphs for Q(n) with an optimal number O(tN+t2) of added edges and small maximum degree. In particular, we show a t-FT graph for Q(n) with 2ctN+ct2((logN)/C)C added edges and maximum degree of O(N/(logC/2N))+4ct.

This paper proposes a new design method of a nonlinear filtering algorithm in continuous-time stochastic systems. The observed value consists of nonlinearly modulated signal and additive white Gaussian observation noise. The filtering algorithm is designed based on the same idea as the extended Kalman filter is obtained from the recursive least-squares Kalman filter in linear continuous-time stochastic systems. The proposed filter necessitates the information of the autocovariance function of the signal, the variance of the observation noise, the nonlinear observation function and its differentiated one with respect to the signal. The proposed filter is compared in estimation accuracy with the MAP filter both theoretically and numerically.

Physics principles of a new type of microwave input amplifiers are described. Cyclotron wave electrostatic amplifier (CWESA) has a low noise level, broad band, switchable gain, super high self-protection against microwave overloads, rapid recovery and small DC consumption. CWESAs are widely used in Russian pulse Doppler radars and other systems.