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.

In current IP-based networks, the application of window-based end-to-end flow control, including TCP, to ensure reliable flows is an essential factor. However, since such a flow control is provided by the end hosts, end-to-end control cannot be applied to decision-making in a time-scale shorter than the round-trip delay. We have previously proposed a diffusion-type flow control mechanism to realize the extremely time sensitive flow control that is required for high-speed networks. In this mechanism, each network node manages its own traffic only on the basis of the local information directly available to it, by using predetermined rules. The implementation of decision-making at each node can lead to optimal performance for the whole network. Our previous studies showed that the mechanism works well, by itself, in high-speed networks. However, to apply this mechanism to actual networks, it needs to be able to coexist with other existing protocols. In this paper, we investigate the performance of diffusion-type flow control coexisting with TCP. We show that diffusion-type flow control can coexist with TCP and the two can be complementary. Then, we show that a combination of both controls achieves higher network performance than TCP alone in high-speed networks.

The location information of ubiquitous objects is one of the key issues for context-aware systems. Therefore, several positioning systems to obtain precise location information have been researched. However, they have scalability and flexibility problems because they need completely configured space with a large number of sensors. To avoid the problems, we proposed a self-organizing location estimation method that uses ad hoc networks and Self-Organizing Maps and needs no prepared space with a large number of sensors. But, as in other similar precise localization methods, the proposed method needs advanced distance measurements unavailable to conventional wireless communication systems. In this paper, the self-organizing location estimation method's modification for distance measurement that uses received signal strength available to conventional wireless communication systems but which fluctuates uncertainly, is described and location estimation accuracy with the modified method is shown.

An algorithm for encoding low-density parity check (LDPC) codes is investigated. The algorithm computes parity check symbols by solving a set of sparse equations, and the triangular factorization is employed to solve the equations efficiently. It is shown analytically and experimentally that the proposed algorithm is more efficient than the Richardson's encoding algorithm if the code has a small gap.

PbZr0.4Ti0.6O3 (PZT) thin films with high crystallinity and high remanant polarization (Pr) have been fabricated by sol-gel deposition with pulsed excimer (XeCl) laser annealing at low process temperatures. The amorphous PZT films were prepared on Pt/Ti/SiO2/Si substrates by a sol-gel method. The deposited amorphous PZT films were annealed at 550 for 10 min. to initiate the nucleation of the PZT perovskite phase, and then annealed with an UV pulsed excimer laser (308 nm) heating at 400. X-ray diffraction (XRD) patterns show that 150-230 mJ/cm2 range multi-shot excimer laser irradiation drastically improved the crystallinity of the PZT perovskite phase. Field emission SEM (FE SEM) image show that the PZT thin film has uniform-sized crystal grains. The ferroelectric properties were found to depend on the laser energy density and shot number.

This paper deals with a synthesis of a nonautonomous system with a stable limit cycle. We propose a synthesis method of a nonautonomous system whose transient trajectories converge to a prescribed limit cycle. We use receding horizon control to control a transient behavior of the nonautonomous system, and confirm its validity by simulation.

A new compact line equalizer is proposed for backplane serial link applications. The equalizer has two control blocks. The feed-forward swing control block determines the optimal low frequency level and the feedback control block detects signal shapes and decides the high-frequency boosting level of the equalizer. Successful equalization is demonstrated over a 1.5 m long PCB trace at 3.125-Gb/s by the circuit realized with 0.18 µm CMOS process. The circuit occupies only 0.16 mm2 and consumes 20 mW with 1.8 V supply.

We propose a novel adaptive linearization technique for a balanced-amplifier array. The technique uses the specific intermodulation distortions (IMDs) at the output ports in the array. The detected IMD power level can be used to optimize the linearizer's characteristics. Because the design does not need as many power detectors and carrier cancel loops as it does amplifiers, we were able to successfully miniaturize the array-antenna system. This paper describes the principles, verified both experimentally and mathematically for a 4-port amplifier array.

This work presents an application of the previously proposed Support Vector Machines Based Generalized Predictive Control (SVM-Based GPC) method [1] to the problem of controlling chaotic dynamics with small parameter perturbations. The Generalized Predictive Control (GPC) method, which is included in the class of Model Predictive Control, necessitates an accurate model of the plant that plays very crucial role in the control loop. On the other hand, chaotic systems exhibit very complex behavior peculiar to them and thus it is considerably difficult task to get their accurate model in the whole phase space. In this work, the Support Vector Machines (SVMs) regression algorithm is used to obtain an acceptable model of a chaotic system to be controlled. SVM-Based GPC exploits some advantages of the SVM approach and utilizes the obtained model in the GPC structure. Simulation results on several chaotic systems indicate that the SVM-Based GPC scheme provides an excellent performance with respect to local stabilization of the target (an originally unstable equilibrium point). Furthermore, it somewhat performs targeting, the task of steering the chaotic system towards the target by applying relatively small parameter perturbations. It considerably reduces the waiting time until the system, starting from random initial conditions, enters the local control region, a small neighborhood of the chosen target. Moreover, SVM-Based GPC maintains its performance in the case that the measured output is corrupted by an additive Gaussian noise.

The global Lanczos algorithm for solving the RLCG interconnect circuits is presented in this paper. This algorithm is an extension of the standard Lanczos algorithm for multiple-inputs multiple-outputs (MIMO) systems. A new matrix Krylov subspace will be developed first. By employing the congruence transformation with the matrix Krylov subspace, the two-side oblique projection-based method can be used to construct a reduced-order system. It will be shown that the system moments are still matched. The error of the 2q-th order system moment will be derived analytically. Furthermore, two novel model-order reduction techniques called the multiple point global Lanczos (MPGL) method and the adaptive-order global Lanczos (AOGL) method which are both based on the multiple point moment matching are proposed. The frequency responses using the multiple point moment matching method have higher coherence to the original system than those using the single point expansion method. Finally, simulation results on frequency domain will illustrate the feasibility and the efficiency of the proposed methods.

In this paper the attention is focused on the numerical study of hyperchaotic 2D-scroll attractors via the Adomian decomposition method. The approach, which provides series solutions of the system equations, is first applied to weakly-coupled Chua's circuits with Hermite interpolating polynomials. Then the method is successfully utilized for achieving hyperchaos synchronization of two coupled Chua's circuits. The reported examples show that the approach presents two main features, i.e., the system nonlinearity is preserved and the chaotic solution is provided in a closed form.

In this paper, we propose a variational method to derive the coefficients of piecewise-linear (PWL) models able to accurately approximate nonlinear functions, which are vector fields of autonomous dynamical systems described by continuous-time state-space models dependent on parameters. Such dynamical systems admit limit cycles, and the supercritical Hopf bifurcation normal form is chosen as an example of a system to be approximated. The robustness of the approximations is checked, with a view to circuit implementations.

In this paper, we propose two techniques to solve the nonlinear constrained optimization problem in large scale mesh-interconnected system. The first one is a diagram-method-based decomposition technique which decomposes the large scale system into some small subsystems. The second technique is a projected-Jacobi-based parallel dual-type method which can solve the optimization problems in the decomposed subsystems efficiently. We have used the proposed algorithm to solve numerous examples of large scale constrained optimization problems in power system. The test results show that the proposed algorithm has computational efficiency with respect to the conventional approach of the centralized Newton method and the state-of-the-art Block-Parallel Newton method.

Mobile IP is a solution to support mobile nodes but it does not handle NEtwork MObility (NEMO). The NEMO Basic Support (NBS) [1] ensures session continuity for all the nodes in a MObile NETwork (MONET). Since the protocol is based on Mobile IP, it inherits from Mobile IP the same fundamental problem such as tunnel convergence, when it is used to support the multicast for NEMO. In this paper, we propose the multicast Route Optimization (RO) scheme in NEMO environments. We suppose that the Mobile Router (MR) has a multicast function and the Nested Mobile Router Information (NeMRI). The NeMRI is used to record a list of the CoAs of all the MRs located below. And it obtains information whether the MRs desire multicast services. Also, we adopt any RO scheme to handle pinball routing. Therefore, we achieve optimal routes for multicasting in NEMO. We also develop analytic models to evaluate the performance of our scheme. We show much lower multicast tree delay and cost in NEMO compared with other techniques such as Bi-directional Tunneling (BT), Remote Subscription (RS), and Mobile Multicast (MoM) based on the NBS protocol.

Video transcoding technique is an efficient mechanism to deliver visual contents to a variety of users who have different network conditions or terminal devices with different display capabilities. In this paper, we propose two types of transcoding methods for adapting the bitrate of streaming video to the bandwidth of the transmission channel; spatial resolution reduction (SRR) transcoding and temporal resolution reduction (TRR) transcoding. The two transcoding methods are alternatively operated according to the requirements of users. Experimental results show that the proposed transcoding methods can preserve image quality while transcoding to the low bitrate.

The transmission of duplicate packets provides a loss-resilience without undue time-delay in the video transmission over packet loss networks. However, this method generally deteriorates the problem of traffic congestion because of the increased bit-rate for duplicate packet transmission. In this paper, we propose a set of techniques for an efficient packetization and transmission of duplicate video packets. The proposed method transmits the duplicate packet containing high priority data that is quite small in volume but very important for the reconstruction of the video. This method significantly reduces the required bit-rate for duplicate transmission. An efficient packetization method is also proposed to reduce additional packet overhead which is required for transmitting the duplicate data. It is shown by simulations that the proposed method remarkably improves the packet loss-resilience for video transmission only with small increase of redundant duplicated data for each slice.

The proposed zero-current switching switched-capacitor (ZCS SC) DC-DC converter is an innovative bi-directional power flow control conversion scheme. A zero-current switching switched-capacitor step-up/step-down bi-directional converter is presented that can improve the current stress problem during bi-directional power flow control processing. It can provide a high voltage conversion ratio of n/ (n-mode/-mode) using four power MOSFET main switches, a set of switched-capacitors and a small resonant inductor. Simulation and experimental results are carried out to verify the concept and performance of the proposed quadruple-mode/quarter-mode bi-directional DC-DC converter.

In this letter, we aim at the study of an OFDM system that employs adaptive modulation techniques to achieve efficient transmission service. In adaptive modulation techniques, a banded AM technique can reduce the number of adaptive modulation information bits and signaling overhead. We evaluate the banded AM technique and compare with Subcarrier AM technique. Moreover, to evaluate the channel condition, we apply the SNR estimation method. Furthermore, to increase the performance of OFDM system, frequency domain pre-equalization is applied. The simulation results have been shown that the OFDM system with adaptive schemes can achieve the efficient transmission for multi-media services.

Network Mobility (NEMO) Basic Support is the standard protocol to provide continuous network connectivity and movement transparency to a group of nodes moving together, as in a vehicle. However, the protocol suffers from sub-optimal routing and packet overhead caused by a bi-directional tunnel between the Mobile Router (MR) connecting the mobile network to the Internet and its Home Agent (HA). When a nested NEMO is formed, these inefficiencies become intolerable for real-time multimedia applications. To optimize the delivery of these packets, this study proposes Optimized NEMO (ONEMO) that is capable of providing an optimal path with minimum packet overhead in various scenarios with nested mobility. The protocol is designed to offer the path with minimum signaling overhead and functional requirements are limited to its MRs. Evaluation through measurements against NEMO Basic Support and comparison among other solutions showed effectiveness of the protocol.

A set of three optical filters was designed and a camera system was developed using these filters in order to capture high-fidelity colors within the gamut of vision. Photographs of a number of highly saturated colors and a combination of the Macbeth chart and 18 pieces of clothing samples of various colors were taken. A 39 matrix was used to convert the camera output signals into XYZ tristimulus data. The tristimulus values of the colors were compared with those of the images captured by the camera. The average color difference, ΔE, for these samples were found to be 2.16 and 1.18, respectively.