In incremental relaying, the destination uses a checking system and requires a retransmission from the relay in case an error happens. After receiving the signal from the relay, the destination combines the signals from the source and the relay and performs detection. However, the combined signal is actually worse because of the erroneous signal from the source. Our scheme eliminates the detrimental signal from the source and uses only the fresh signal from the relay, resulting in a large performance improvement and reduced complexity. The symbol error rate (SER) and its upper bound are established to analyze the power allocation strategy. Simulations verify the rightness of the theoretic studies, and many benefits of cooperative ARQ schemes are revealed.

This paper provides a closed form expression for calculating the bit error rate of the decode-and-forward relay protocol that uses equal-gain combining (EGC) at the destination with an arbitrary number of relays. We have shown that EGC technique for decode-and-forward relay scheme offers remarkable diversity advantage over direct transmission. In addition, we also study the impact of combining techniques on the performance of the system by comparing a system that uses EGC to one that uses maximum ratio combining (MRC) & selection combining (SC). Simulations are performed to confirm our theoretical analysis.

Although a lot of works for location management in wireless networks have been reported in the literature, most of the works have been focused on designing per-user-based strategies. This means that they can achieve the performance enhancement only for a certain class of mobile users with a specific range of CMR (call-to-mobility ratio). However, these per-user-based strategies can actually degrade the performance if a user's CMR changes significantly. Therefore, an efficient uniform location management strategy, which can be commonly applied to all mobile users regardless of their CMR, is proposed and analyzed in this paper. The motivation behind the proposed strategy is to exploit the concepts of the two well-known existing strategies: the location caching strategy and the local anchor strategy. That is, the location caching strategy exploits locality in a user's calling pattern, whereas the local anchor strategy exploits locality in a user's mobility pattern. By exploiting these characteristics of both strategies together with the profile management at the HLR (home location register), the proposed strategy can reduce the frequent access to the HLR, and thus effectively results in significant reduction in terms of the total location management cost. The analytical results also demonstrate that the proposed strategy can be uniformly applied to all mobile users, while always maintaining the performance gain over the IS-41 standard regardless of a user's CMR and the network traffic conditions.

The damage to the organic layer of aluminum (III) bis(2-methyl-8-quninolinato)-4-phenylphenolate (BAlq) film was investigated on the basis of the change in photoluminescence (PL) intensity. To suppress the bombardment of the substrate with high-energy particles such as γ-electrons and negative oxygen ions, we used a facing-target sputtering (FTS) system. A marked reduction, however, of the PL intensity of the organic layer was still observed upon the deposition of an indium tin oxide (ITO) film on the organic film. To reduce this reduction, we proposed the insertion of a sector-shaped metal shield near the target electrode, and we showed its effectiveness in reducing the damage. This reduction of the damage is thought to be caused by the elimination of γ-electrons incident to the organic film surface escaping from the target area near the substrate side. We confirmed that high-energy electron bombardment leads to a significant reduction of PL intensity of the organic layer. This indicates that high-energy electrons incident to the organic film surface play a key role in the damage of the organic layer during the sputtering process.

We developed new principle of electronic paper that is one side (for 2D image) or double side (for stereoscopic 3D image) light printable rewritable matter with polarization dependent gray scale. It consists of one or two liquid crystal displays based on Optical Rewritable (ORW) technology, which is the development of rotation azo-dye photoalignment. Each ORW display uses bare plastic or polarizers as substrates. The conductor is not required, as the image is formed by rewritable states of azimuthal direction, which results in 2D pattern of the liquid crystal twist angle. Continuous grey image maintains proper performance even when the device is bent. Simple construction provides durability and low cost, thin substrates minimize parallax for 3D image. Fluorescent dye dopant of liquid crystal partly absorbs light in blue and re-emit in green specter range improving photopic reflection and enhancing color of the ORW e-paper.

This paper proposes a novel chaotic multiple-bits modulation scheme that uses the parameters in the map as data carrier for chaotic digital communication. Chaotic signals modulated with the parameters corresponding to the information to be transmitted are sent to the receiver. The information sent to the receiver can be decoded by a correlation detector. This scheme can increase the number of transmittable information bit per unit carrier signals by increasing the number of mapping parameters to be used for modulation. We verify the performance of this scheme using bit error rate (BER) through computer simulation. Also, we compare the performance of the proposed method with a conventional single-bit modulation scheme.

Experimental and theoretical studies of light coupling to various magnetic nanostructured media and nanocomposites are briefly reported. Enhancement of the magneto-optical response is shown to occur when the constitutive materials of photonic crystals are magnetic. Transmission and reflection types of 1D magnetophotonic crystals (MPCs) have been studied. New possibility to enhance the magneto-optical response has been found when utilizing localized surface plasmon resonances in bismuth-substituted yttrium iron garnet (Bi:YIG) films impregnated with Au nanoparticles. Examples of integrated optic devices are discussed in which functional elements are 1D and 2D magnetophotonic crystals.

We propose to integrate a single lens on top of multiple OLEDs. Angular distribution of the light emitted from the lens surface is altered by turning on the OLEDs selectively. We can use such a light source as a backlight for a liquid crystal display to switch its viewing angle range and/or to display multiple images in different directions. Pixel-level integration would allow one to construct an OLED display with a similar emission angle control.

This paper investigates the problem of nonpreemptively scheduling independent parallel tasks in an environment with multiple machines, which is motivated from the recent studies in scheduling tasks in a multi-machine environment. In this scheduling environment, each machine contains a number of identical processors and each parallel task can simultaneously require a number of processors for its processing in any single machine. Whenever tasks are processed in parallel in a parallel machine, message communication among processors is often inevitable. The problem of finding a shortest schedule length on scheduling independent parallel tasks with the consideration of communication overhead in a multi-machine environment is NP-hard. The aim of this paper is to propose a heuristic algorithm for this kind of problem and to analyze the performance bound of this heuristic algorithm.

In this paper we analytically investigate the generalization performance of learning using correlated inputs in the framework of on-line learning with a statistical mechanical method. We consider a model composed of linear perceptrons with Gaussian noise. First, we analyze the case of the gradient method. We analytically clarify that the larger the correlation among inputs is or the larger the number of inputs is, the stricter the condition the learning rate should satisfy is, and the slower the learning speed is. Second, we treat the block orthogonal projection learning as an alternative learning rule and derive the theory. In a noiseless case, the learning speed does not depend on the correlation and is proportional to the number of inputs used in an update. The learning speed is identical to that of the gradient method with uncorrelated inputs. On the other hand, when there is noise, the larger the correlation among inputs is, the slower the learning speed is and the larger the residual generalization error is.

A QoS management technique based on an autonomous decentralized mobility system, which is an autonomous decentralized system enhanced to provide mobile stations with information about urgent roadway situations, is proposed in this paper. This technique enables urgent messages to be flexibly and quickly transmitted to mobile stations by multiple decentralized base stations using dedicated short range communication. It also supports the easy addition of additional base stations. Each station autonomously creates information-delivery communities based on the urgency of the messages it receives through the roadside network and the distances between the senders and receivers. Each station dynamically determines the urgency of messages according to the message content and the speed of the mobile stations. Evaluation of this technique applied to the Smart Gateway system, which provides driving-assistance services to mobile stations through dedicated short-range communication, demonstrated its effectiveness and that it is suitable for actual systems.

We propose and demonstrate a scheme enhancing the performance of optical access networks with Manchester coded downstream and re-modulated NRZ coded upstream. It is achieved by threshold level control of a limiting amplifier at a receiver, and the minimum sensitivity of upstream is significantly improved for the re-modulation scheme with 5 Gb/s Manchester coded downstream and 2.488 Gb/s NRZ upstream data rates.

Based on an estimation model of video subjective quality, a bandwidth reallocation strategy for video communications on NGN is presented. Experimental results show that the average PSNR of recovery video quality can be greatly increased by using the proposed method when the network bandwidth decreases.

Wireless ad hoc communications such as ad hoc networks have been attracting researchers' attention. They are expected to become a key technology for "ubiquitous" networking because of the ability to configure wireless links by nodes autonomously, without any centralized control facilities. Adaptive array antennas (AAA) have been expected to improve the network efficiency by taking advantage of its adaptive beamforming capability. However, it should be noted that AAA is not almighty. Its interference cancellation capability is limited by the degree-of-freedom (DOF) and the angular resolution as a function of the number of element antennas. Application of AAA without attending to these problems can degrade the efficiency of the network. Let us consider wireless ad hoc communication as a target application for AAA, taking advantage of AAA's interference cancellation capability. The low DOF and insufficient resolution will be crucial problems compared to other wireless systems, since there is no centralized facility to control the nodes to avoid interferences in such systems. A number of interferences might impinge on a node from any direction of arrival (DOA) without any timing control. In this paper, focusing on such limitations of AAA applied in ad hoc communications, we propose a new scheme, Forward Interference Avoidance (FIA), using AAA for ad hoc communications in order to avoid problems caused by the limitation of the AAA capability. It enables nodes to avoid interfering with other nodes so that it increases the number of co-existent wireless links. The performance improvement of ad hoc communications in terms of the number of co-existent links is investigated through computer simulations.

In this letter, we emphasize the performance associated problem of the TCP protocol in the wired-wireless networks. It is shown that the increase of TCP congestion window is strongly influenced by the wireless link. To accelerate the increase of TCP congestion window regardless of wireless link conditions we adopt a fast snoop agent that sends indirect acknowledgement to the sender. Simulation results show that the proposed scheme achieves higher throughput with small data size.

Harmonic balance (HB) method is well known principle for analyzing periodic oscillations on nonlinear networks and systems. Because the HB method has a truncation error, approximated solutions have been guaranteed by error bounds. However, its numerical computation is very time-consuming compared with solving the HB equation. This paper proposes an algebraic representation of the error bound using Grobner base. The algebraic representation enables to decrease the computational cost of the error bound considerably. Moreover, using singular points of the algebraic representation, we can obtain accurate break points of the error bound by collisions.

Finite impulse response (FIR) filtering is the most computationally intensive operation in the channelizer of a wireless communication receiver. Higher order FIR channel filters are needed in the channelizer to meet the stringent adjacent channel attenuation specifications of wireless communications standards. The computational cost of FIR filters is dominated by the complexity of the coefficient multipliers. Even though many methods for reducing the complexity of filter multipliers have been proposed in literature, these works focused on lower order filters. This paper presents a coefficient-partitioning-based binary subexpression elimination method for realizing low power FIR filters. We show that the FIR filters implemented using proposed method consume less power and achieve speed improvement compared to existing filter implementations. Design examples of the channel filters employed in the Digital Advanced Mobile Phone System (D-AMPS) and Personal Digital Cellular (PDC) receivers show that the proposed method achieved 23% average reductions of full adder and power consumption and 23.3% reduction of delay over the best existing method. Synthesis results show that the proposed method offers average area reduction of 8% and power reduction of 22% over the best known method in literature.

In networked control systems, uncontrollable events may unexpectedly occur in a plant before a proper control action is applied to the plant due to communication delays. In the area of supervisory control of discrete event systems, Park and Cho [5] proposed the notion of delay-nonconflictingness for the existence of a supervisor achieving a given language specification under communication delays. In this paper, we present the algebraic properties of delay-nonconflicting languages which are necessary for solving supervisor synthesis problems under communication delays. Specifically, we show that the class of prefix-closed and delay-nonconflicting languages is closed under intersection, which leads to the existence of a unique infimal prefix-closed and delay-nonconflicting superlanguage of a given language specification.

A new type of algorithm for predicting the mechanical faults of a vacuum circuit breaker (VCB) based on an artificial neural network (ANN) is proposed in this paper. There are two types of mechanical faults in a VCB: operation mechanism faults and tripping circuit faults. An angle displacement sensor is used to measure the main axle angle displacement which reflects the displacement of the moving contact, to obtain the state of the operation mechanism in the VCB, while a Hall current sensor is used to measure the trip coil current, which reflects the operation state of the tripping circuit. Then an ANN prediction algorithm based on a sliding time window is proposed in this paper and successfully used to predict mechanical faults in a VCB. The research results in this paper provide a theoretical basis for the realization of online monitoring and fault diagnosis of a VCB.

A binaural hearing assistance system based on the frequency domain binaural model has been previously proposed. The system can enhance a signal coming from a specific direction. Since the system utilizes a binaural signal, an inter-channel communication between left and right subsystems is required. The bit rate reduction in inter-channel communication is essential for the detachment of the headset from the processing system. In this paper, the performance of a system which uses a differential pulse code modulation codec is examined and the relationship between the bit rate and sound quality is discussed.