A compact, nonradiative, and easy fabricated left-handed material composed of planar circuit-type resonators in a cutoff waveguide is proposed. It is shown that the TE-type evanescent field is equivalent to the field in ε-negative material and the resonator works as a particle with negative permeability. The existence of a left-handed mode is ensured by a field distribution and a dispersion relation. After showing that the two constituents have an influence on the permittivity or the permeability of the material, on the basis of an idea of impedance, the material is matched to a conventional waveguide. Finally the material can be applied to a left-handed leaky-wave antenna.

A Huffman sequence has a zero-sidelobe aperiodic autocorrelation function except at both shift ends. This paper presents orthogonal sets of the zero correlation zone (ZCZ) Huffman sequences and the application to a quasi-synchronous CDMA system with interferences suppressed. The sequences with low or large peak values are constructed on the basis of sequence spectra corresponding to multiple convolution of elementary sequences, and include the ZCZ sequences. The CDMA system is constructed from the ZCZ sequences, and suppresses intersymbol and interchannel interferences.

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.

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.

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.

This paper presents constructions of two kinds of sets of sequences with a zero correlation zone, called ZCZ code, which can reach the upper bound of the member size of the sequence set. One is a ZCZ code which can be constructed by a unitary matrix and a perfect sequence. Especially, a ternary perfect sequence with elements 1 and zero can be used to construct the proposed ZCZ code. The other is a ZCZ code of pairs of ternary sequences and binary sequences which can be constructed by an orthogonal matrix that includes a Hadamard matrix and an orthogonal sequence pair. As a special case, an orthogonal sequence pair, which consists of a ternary sequence and a binary sequence, can be used to construct the proposed ZCZ code. These codes can provide CDMA systems without co-channel interference.

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.

A temporal error concealment algorithm for the block-based video coder has been proposed. The concept of block overlapping is adopted to conceal the erroneous blocks, and the recovered pixels are estimated by the weighted sum from the overlapping. The overlapping weighting matrix has been carefully selected in order to fully exploit the spatial-temporal correlation between boundary blocks and the lost block. Furthermore, the motion vector for the lost block has been recovered by considering the best results for the overlapping. The experimental results are shown by integrating our algorithm into the H.263+ coder.

The proportional delay differentiation (PDD) model provides consistent packet delay differentiation between classes of service. Currently, the present schedulers performing the PDD model cannot achieve desired delay proportion observed in short timescales under light/moderate load. Thus, we propose a Non-Work-Conserving (NWC) scheduler, which utilizes the pseudo-waiting time for an empty queue and forces each class to compare its priority with those of all other classes. Simulation results reveal that NWC outperforms all current schedulers in achieving the PDD model. However, NWC suspends the server from transmitting packets immediately if an empty class has the maximum priority, resulting in an idle server. Therefore, we further propose two approaches, which will serve a best-effort class during this idle time. Compared with other schedulers, the proposed approaches can provide more predictable and controllable delay proportion, accompanied with satisfactory throughput and average queuing delay.

In this letter, we propose an efficient user selection algorithm aiming to select users with less spatially correlation and meet the user number limit of zero-forcing beamforming in downlink multiuser MIMO systems. This algorithm yields a considerable complexity reduction with only a small loss in performance and it only needs partial users' CSI feedback. Coupled with the algorithm, a null space updating method in O(K2) time and a modified proportional fair scheduling algorithm are also proposed.

In this letter, we elucidate the ergodic capacity of multiple-input multiple-output (MIMO) systems with M-ary phase-shift keying (MPSK) modulation and time-multiplexed pilots in frequency-flat Rayleigh fading environment. With linear minimum mean square error (LMMSE) channel estimation, the optimal pilots design is presented. For mathematical tractability, we derive an easy-computing closed-form lower bound of the channel capacity. Based on the lower bound, the optimal power allocation between the data and pilots is also presented in closed-form, and the optimal training length is investigated by numerical optimization. It is shown that the transmit scheme with equal training and data power and optimized training length provides suboptimal performance, and the transmit scheme with optimized training length and training power is optimal. With the latter scheme, in most situations, the optimal training length equals the number of the transmit antennas and the corresponding optimal power allocation can be easily computed with the proposed formula.

A novel approach of robust adaptive beamforming (RABF) is presented in this paper, aiming at robustness against both finite-sample effects and steering vector mismatches. It belongs to the class of diagonal loading approaches with the loading level determined based on worst-case performance optimization. The proposed approach, however, is distinguished by two points. (1) It takes finite-sample effects into account and applies worst-case performance optimization to not only the constraints, but also the objective of the constrained quadratic equation, for which it is referred to as joint worst-case RABF (JW-RABF). (2) It suggests a simple closed-form solution to the optimal loading after some approximations, revealing how different factors affect the loading. Compared with many existing methods in this field, the proposed one achieves better robustness in the case of small sample data size as well as steering vector mismatches. Moreover, it is less computationally demanding for presenting a simple closed-form solution to the optimal loading. Numerical examples confirm the effectiveness of the proposed approach.

In this paper, we propose a robust statistical framework for extracting scenes from a baseball broadcast video. We apply multi-stream hidden Markov models (HMMs) to control the weights among different features. To achieve a large robustness against new scenes, we used a common simple structure for all the HMMs. In addition, scene segmentation and unsupervised adaptation were applied to achieve greater robustness against differences in environmental conditions among games. The F-measure of scene-extracting experiments for eight types of scene from 4.5 hours of digest data was 77.4% and was increased to 78.7% by applying scene segmentation. Furthermore, the unsupervised adaptation method improved precision by 2.7 points to 81.4%. These results confirm the effectiveness of our framework.

The optical ZCZ code is a set of pairs of binary and bi-phase sequences with zero correlation zone. An optical M-ary direct sequence spread spectrum (M-ary/DS-SS) system using this code can detect a desired sequence without interference of undesired sequences. However, the bank of matched filters in a receiver circuit may fall into large scale. In this paper, we propose the compact construction of a bank of matched filters for an M-ary/DS-SS system using an optical ZCZ code. This filter bank can decrease the number of 2-input adders from O(N2) to O(N) and delay circuits from O(N2) to O(Nlog 2 N), respectively, and is implemented on a field programmable gate array (FPGA) corresponding to 400,000 logic gates.

A plane drawing of a plane graph is called a rectangular drawing if every face including the outer face is a rectangle. A based rectangular drawing is a rectangular drawing with a designated base line segment on the outer face. An algorithm to generate all based rectangular drawings having exactly n faces is known. The algorithm generates each based rectangular drawing having exactly n faces in constant time "on average." In this paper, we give another simple algorithm to generate all based rectangular drawings having exactly n faces. Our algorithm generates each based rectangular drawing having exactly n faces in constant time "in the worst case." Our algorithm generates each based rectangular drawing so that it can be obtained from the preceding one by at most three operations and does not output entire drawings but the difference from the preceding one. Therefore the derived sequence of based rectangular drawings is a kind of combinatorial Gray code for based rectangular drawings.

Cell assembly is one of explanations of information processing in the brain, in which an information is represented by a firing space pattern of a group of plural neurons. On the other hand, effectiveness of neural network has been confirmed in pattern recognition, system control, signal processing, and so on, since the back propagation learning was proposed. In this study, we propose a new network structure with affordable neurons in the hidden layer of the feedforward neural network. Computer simulated results show that the proposed network exhibits a good performance for the back propagation learning. Furthermore, we confirm the proposed network has a good generalization ability.

Barker sequences have been used in many existing communications and ranging systems. Unfortunately, the longest known biphase and quadriphase Barker sequences are of lengths 13 and 15, respectively. In this paper, we introduce the so-called quasi-Barker sequences which achieve the minimum peak sidelobe level one within a certain window centered at the mainlobe. As our key results, all the best biphase and quadriphase quasi-Barker sequences of lengths up to 36 and 21, respectively, were obtained by an efficient computer search. These sequences may provide better multipath resistance and tracking accuracy in ranging applications.

Overlay networks, such as P2P, Grid, and CDN, have been widely deployed over physical IP networks. Since simultaneous overlay networks compete for network resources, their selfish behaviors to improve their application-oriented QoS disrupt each other. To enhance the collective performance and improve the QoS at the application level, we consider so-called the overlay network symbiosis where overlay networks cooperate with each other. In this paper, we proposed a cooperative mechanism for hybrid P2P file-sharing networks, where peers can find more files and exchange files with more peers. Through simulation experiments, we verified the effectiveness of cooperation from view points of application and system.

Internet Virtual Private Networks (VPNs) across geographically distributed users' networks are ideal for ad-hoc group activities, such as online gaming, over the Internet. However, users find it difficult to determine and set the configurations of the VPN routers and hosts rapidly enough for ad-hoc usage, due to the need for consistency of such configurations over the users' networks. Moreover, the number of operators is insufficient to help all users. Hence, the automatic determination and setting of such configurations from the management server is desirable. Existing auto-configuration methods are insufficient for ad-hoc usage because they cannot rapidly determine and set the hosts' configurations to be consistent with the VPN and user's network they are joining. To enable ad-hoc creation of and joining to a VPN by the users themselves, we propose a new method that utilizes the Dynamic Host Configuration Protocol (DHCP), which can automatically set the configurations of many existing hosts. The DHCP server's and relay agents' configurations are automatically determined and set by the VPN management server, based on the user request, so that the hosts can be auto-configured to be consistent with the VPN and the user's network they are joining, from the DHCP server via the autoconfigured DHCP relay agents. To evaluate the time overhead of our proposed method, we implemented a test bed, including 10 VPN routers, a VPN management server, and a DHCP server. In this evaluation, the DHCP server is auto-configured for each new VPN in less than 1 second, and the DHCP relay agents on the VPN routers are auto-configured in less than 5 percent of the total time for configuring the VPN routers, regardless of the total number of the VPN routers in a VPN. These results show that the proposed method can auto-configure the VPN routers and hosts simultaneously with the DHCP, while ensuring sufficient rapidity of the entire auto-configuration operation for ad-hoc usage.

Based on the Khatri-Rao matrix product, we propose a novel unitary space-time modulation design called KR-USTM in this paper. Different from existing USTM schemes, such as the systematic approach and space-time frequency-shift keying (ST-FSK), KR-USTM does not require any computer search and can be applied to any number of transmit antennas. Moreover, the special structure of KR-USTM also makes it a high-rate scheme and achieve full antenna diversity as well as lower decoding complexity. Simulation results show that the proposed KR-USTM constellation achieves error performance comparable to existing USTM designs at low rates, while it outperforms them at high rates.