We have researched high dimensional parity-check (HDPC) codes that give good performance over a channel that has a very high error rate. HDPC code has a little coding overhead because of its simple structure. It has hard-in, maximum detected bit flipping (MDBF) decoding that has reasonable decoding performance and computational cost. In this paper, we propose a modified algorithm for MDBF decoding and compare the proposed MDBF decoding with conventional hard-in decoding.

Gastric cancer is a great part of the cancer occurrence and the mortality from cancer in Korea, and the early detection of gastric cancer is very important in the treatment and convalescence. This paper, for the early detection of gastric cancer, proposes the analysis system of an endoscopic image of the stomach, which detects abnormal regions by using the change of color in the image and by providing the surface tissue information to the detector. While advanced inflammation or cancer may be easily detected, early inflammation or cancer is difficult to detect and requires more attention to be detected. This paper, at first, converts an endoscopic image to an image of the IHb (Index of Hemoglobin) model and removes noises incurred by illumination and, automatically detects the regions suspected as cancer and provides the related information to the detector, or provides the surface tissue information for the regions appointed by the detector. This paper does not intend to provide the final diagnosis of abnormal regions detected as gastric cancer, but it intends to provide a supplementary mean to reduce the load and mistaken diagnosis of the detector, by automatically detecting the abnormal regions not easily detected by the human eye and this provides additional information for diagnosis. The experiments using practical endoscopic images for performance evaluation showed that the proposed system is effective in the analysis of endoscopic images of the stomach.

Designable task allocation systems which consist of identical agents using stochastic automata are suggested. From the viewpoint of the group response and the individual behavior, the performances of a simple model and an improved one are compared numerically. Robots experiments are performed to compare between the two models.

SIP is promising for VoIP signaling to support personal mobility. This paper first introduces and compares single registration (SR) and multiple registration (MR) for personal mobility. The SR scheme is weak in support of personal mobility without user's assistance. In contrast, the MR scheme supports personal mobility inherently by using sequential search or pure parallel search. However, sequential search may suffer from long delay for call setup, while pure parallel search consumes network resource. In this paper, we propose pipelined search for multiple registration. Both simulation and analytic results show that the proposed scheme compromises the two schemes in terms of delay and consuming network resource.

Providing multimedia services with a quality-of-service guarantee in mobile wireless networks presents more challenges due to user's mobility and limited bandwidth resource. In order to provide seamless multimedia services in the next-generation wireless networks, efficient call admission control algorithm must be developed. A novel borrowing-based call admission control policy is proposed in this paper as a solution to support quality-of-service guarantees in the mobile multimedia wireless networks. Based on the existing network conditions, the proposed scheme makes an adaptive decision for bandwidth allocation and call admission by employing attribute-measurement mechanism, dynamic time interval reservation strategy, and service-based borrowing strategy in each base station. We use the dynamically adaptive approaches to reduce the connection-blocking probability and connection-dropping probability, and to increase the bandwidth utilization, while the quality-of-service guarantees can be maintained at a comfortable level for mobile multimedia wireless networks. Extensive simulation results show that our proposed scheme outperforms the previously proposed scheme in terms of connection-blocking probability, connection-dropping probability, and bandwidth utilization, while providing highly satisfying degree of quality-of-service in mobile communication systems.

In a typical OFDM system, a time domain equalizer (TEQ) can be used in order to reduce the channel length, allowing for shortening of the Cyclic Prefix (CP). In this paper, a novel TEQ method is proposed for OFDM systems, which can reduce implementation complexity without sacrificing performance. Furthermore, the length of the proposed TEQ may be arbitrary. For time-varying channels, an adaptive method is also developed to track the variation of the optimum TEQ coefficients rather than recomputing inversion of the channel matrix.

For fitting an ellipse to a point sequence, ML (maximum likelihood) has been regarded as having the highest accuracy. In this paper, we demonstrate the existence of a "hyperaccurate" method which outperforms ML. This is made possible by error analysis of ML followed by subtraction of high-order bias terms. Since ML nearly achieves the theoretical accuracy bound (the KCR lower bound), the resulting improvement is very small. Nevertheless, our analysis has theoretical significance, illuminating the relationship between ML and the KCR lower bound.

CMOS poly-Si thin-film transistors (TFTs) were fabricated through crystallization and GILD processes by a novel selected area laser assisted (SALA) system. The system enables a local area irradiation of small beams of a pulsed solid-state laser of frequency tripled Nd:YAG. The novel TFT process eliminated 3 doping mask steps of the conventional process. On-off current ratios for both types of poly-Si TFTs were improved by SALA. The field effect mobility of n- and p-channel TFTs is 84 cm2/Vs and 75 cm2/Vs, respectively.

In this paper, we propose to employ an extension to the natural gradient algorithm for robust Independent Component Analysis against outliers. The standard natural gradient algorithm does not exhibit this property since it employs nonrobust sample estimates for computing higher order moments. In order to overcome this drawback, we propose to use robust alternatives to higher order moments, which are comparatively less sensitive to outliers in the observed data. Some computer simulations are presented to show that the proposed method, as compared to the standard natural gradient algorithm, gives better performance in the presence of outlying data.

In this paper, we present a resource monitoring and selection method for rapid turnaround grid applications (for example, within 10 seconds). The novelty of our method is the distributed evaluation of resources for rapidly selecting the appropriate idle resources. We integrate our method with a widely used resource management system, namely the Monitoring and Discovery System 2 (MDS2), and compare our method with the original MDS2 in terms of the performance and the scalability. The performance is measured using a 64-node cluster of PCs and the scalability is analyzed using a theoretical model and the measured performance. The experimental results show that our method reduces the resource selection time by 82%, as compared with the original MDS2. The scalability analysis also indicates that our method can keep the resource selection time within 1 second, up to 500 nodes in local-area-network (LAN) environments. In addition, some simulation results are presented to estimate the impact of our method for wide-area-network (WAN) environments.

Nonlinear modeling of complex irregular systems constitutes the essential part of many control and decision-making systems and fuzzy logic is one of the most effective algorithms to build such a nonlinear model. In this paper, a new approach to fuzzy modeling is proposed. The model considered herein is the well-known Sugeno-type fuzzy system. The fuzzy modeling algorithm suggested in this paper is composed of two phases: coarse tuning and fine tuning. In the first phase (coarse tuning), a successive clustering algorithm with the fuzzy validity measure (SCFVM) is proposed to find the number of the fuzzy rules and an initial fuzzy model. In the second phase (fine tuning), a moving genetic algorithm with partial encoding (MGAPE) is developed and used for optimized tuning of membership functions of the fuzzy model. Two computer simulation examples are provided to evaluate the performance of the proposed modeling approach and compare it with other modeling approaches.

Overlay networks are expected to be a promising technology for the realization of QoS (Quality of Service) control. Overlay networks have recently attracted considerable attention due to the following advantages: a new service can be developed in a short duration and it can be started with a low cost. The definition and necessity of the overlay network is described, and the classification of various current and future overlay networks, particularly according to the QoS feature, is attempted. In order to realize QoS control, it is considered that routing overlay and session overlay are promising solutions. In particular, session and overlay networks are explained in detail since new TCP protocols for QoS instead of current TCP protocols that control congestion in the Internet can be used within overlay networks. However, many open issues such as scalability still need further research and development although overlay networks have many attractive features and possess the potential to become a platform for the deployment of new services.

File-sharing Peer-to-Peer systems are effective for autonomous data retrieval and provision over the networks. However, the early data retrieval schemes such as Gnutella and Local Indices have low performance and large overhead. In order to solve weakness of early schemes, this paper proposes a dynamic scheme for data retrieval and provision, in which indices are adaptively allocated in appropriate nodes to variation of traffic patterns caused by query messages. The simulation experimental results show that the proposed scheme has good performance with reasonable overhead even when the traffic patterns vary as time proceeds.

To increase the yield of data processing circuits such as adders and logic operation circuits, the bit-slice reconfiguration design has been proposed as an efficient redundant technology for defect-tolerance. Wallace multipliers are a well-known class of high-speed parallel multipliers. Unfortunately, the bit-slice reconfiguration design is not applicable to Wallace multipliers because Wallace multipliers do not have regular bit-slice structure. Therefore, redundant designs for Wallace multipliers have been regarded impossible. This paper proposes a redundant design for Wallace multipliers. In order to design redundant Wallace multipliers, first, 2n heterogeneous slices are considered in a non-redundant nn Wallace multiplier. The proposed redundant Wallace multipliers contain reconfigurable slices which can play the role of both i-th and (i+1)-th slices. Since the i-th slice has a similar structure to the (i+1)-th slice, the reconfigurable slice is not much larger than the i-th slice. This paper also shows a repair procedure for the proposed design. This paper evaluates the proposed design from the viewpoint of the yield, area, effective yield and delay time. For example, the yield of a 3232 Wallace multiplier increases from 0.30 to 0.41 by applying the proposed design while the area increases by a factor of 1.21.

Quasi-orthogonal Space Time Block Code (STBC) was designed to provide full transmission rate when using more than two antennas. However, it cannot have a full diversity gain because of the interference resulted from its quasi orthogonality property. In order to achieve full diversity from quasi-orthogonal STBC, the interference can be removed by a Simple Correlation Canceling (SCC) algorithm which improves a system performance significantly. However, the SCC algorithm has a disadvantage that produces noise enhancement, thereby resulting in performance degradation. Accordingly, without increasing an extra system complexity, an unequal power allocation scheme in a transmitter is proposed to achieve a better system performance than the conventional STBC system using the SCC algorithm. Also, the unequal power allocation scheme enables a receiver to use a simple decoding procedure that does not produce noise enhancement.

Design of optimal controllers satisfying performance criteria of minimum tracking error and disturbance level for an interval system using a multi-objective evolutionary approach is proposed in this paper. Based on a worst-case design philosophy, the design problem is formulated as a minimax optimization problem, subsequently solved by a proposed two-phase multi-objective genetic algorithm (MOGA). By using two sets of interactive genetic algorithms where the first one determines the maximum (worst-case) cost function values for a given set of controller parameters while the other one minimizes the maximum cost function values passed from the first genetic algorithm, the proposed approach evolutionarily derives the optimal controllers for the interval system. To suitably assess chromosomes for their fitness in a population, root locations of the 32 generalized Kharitonov polynomials will be used to establish a constraints handling mechanism, based on which a fitness function can be constructed for effective evaluation of the chromosomes. Because of the time-consuming process that genetic algorithms generally exhibit, particularly the problem nature of minimax optimization, a parallel computation scheme for the evolutionary approach in the MATLAB-based working environment is also proposed to accelerate the design process.

The Schaub bound is one of well-known lower bounds of the minimum distance for given cyclic code C, and defined as the minimum value, which is a lower bound on rank of matrix corresponding a codeword, in defining sequence for all sub-cyclic codes of given code C. In this paper, we will try to show relationships between the Schaub bound, the Roos bound and the shift bound from numerical experiments. In order to reduce computational time for the Schaub bound, we claim one conjecture, from numerical examples in binary and ternary cases with short code length that the Schaub bound can be set the value from only defining sequence of given code C.

In this paper, a parallel combinatory spread spectrum (PC/SS) system using a constant amplitude signaling scheme is proposed. The amplitude of the transmitted signal from multicode transmission systems such as PC/SS systems have a large dynamic range which requires that amplifiers have a wide linearity in the transmitter. From a view point of power efficiency, however, it is reasonable to use non-linear amplifiers rather than linear ones. In that case, the bit error rate performance must degrade because of non-linear distortion. The proposed system can avoid influence of the non-linear amplifiers by making the transmitted signal have a constant amplitude. The bit error rate performance and the data transmission rate performance are investigated. They prove that the proposed system is an attractive candidate among the constant amplitude signaling systems.

Virtual Private Networks (VPNs) are overlay networks established on top of a public network backbone with the goal of providing a service comparable to Private Networks (PNs). The recently proposed VPN hose-model provides customers with flexible and convenient ways to specify their bandwidth requirements. To meet the specified bandwidth requirements, the Network Service Provider (NSP) must reserve sufficient bandwidth on the data transmission paths between each pair of endpoints in a VPN. In addition, the reliability of a VPN depends on the reliability of the data transmission paths. Italiano et al. proposed an algorithm that finds a set of backup paths for a given VPN (VPN tree) under the single-link failure model [1]. When a link failure is detected on a VPN tree, a backup path corresponding to the failed link can be activated to restore the disconnected VPN tree into a new one, thereby ensuring the reliability of the VPN. However, Italiano's algorithm cannot guarantee that the specified bandwidth requirement of the given VPN under the single-link failure model will be met. To address this issue, we propose a new backup path set selection algorithm called BANGUAD in this paper. In addition, the problem of establishing multiple bandwidth-guaranteed hose-model VPNs under the single-link failure model has not been investigated previously. However in this problem, bandwidth-sharing algorithms have the potential to improve the performance of a provisioning algorithm significantly. Therefore, we also propose a bandwidth sharing algorithm and three provisioning algorithms for establishing multiple bandwidth-guaranteed hose-model VPNs under the single-link failure model. Simulations that compare the performance of the proposed algorithms are reported.

We extend the sliding block code in symbolic dynamics to transform J (≥2) sequences of Markov chains with time delays. Under the assumption that the chains are irreducible and aperiodic, we prove the central limit theorem (CLT) for the normalized sums of extended sliding block codes from J sequences of Markov chains. We apply the theorem to the system analysis of asynchronous spread spectrum multiple access (SSMA) communication systems using spreading sequences of Markov chains. We find that the standard Gaussian approximation (SGA) for estimations of bit error probabilities in such systems is the 0-th order approximation of the evaluation based on the CLT. We also provide a simple theoretical evaluation of bit error probabilities in such systems, which agrees properly with the experimental results even for the systems with small number of users and low length of spreading sequences.