The codes by the u/u+v construction have the extended error capacity for additional Hamming weight. It is a simple way to construct a large size block code using smaller ones. In this letter, low density parity check (LDPC) codes on u/u+v construction are investigated. Consequently, the study can enrich the family of LDPC codes and provide some special LDPC implementations.

Ultrafast all optical switching using pulse trapping by 100 fs ultrashort soliton pulse across zero dispersion wavelength is investigated. The characteristics of pulse trapping are analyzed both experimentally and numerically. Using the pulse trapping, 1 THz ultrafast all optical switching is demonstrated experimentally. Arbitral one pulse is picked off from pulse train. Pulse trapping for CW signal is also demonstrated and ultrashort pulse is generated by pulse trapping. From these investigation, it is shown that ultrafast all optical switching up to 2 THz can be demonstrated using pulse trapping.

In this paper we give the necessary and sufficient conditions for 2-dimensional discrete-time systems described by the signum function to be stable.

In order to perform the registration of virtual objects in vision-based augmented reality systems, the estimation of the relation between the real and virtual worlds is needed. This paper presents a three-point vision-based registration method for video see-through augmented reality systems using binocular cameras. The proposed registration method is based on a combination of monocular and stereoscopic registration methods. A correction method that performs an optimization of the registration by correcting the 2D positions in the images of the marker feature points is proposed. Also, an extraction strategy based on color information is put forward to allow the system to be robust to fast user's motion. In addition, a quantification method is used in order to evaluate the stability of the produced registration. Timing and stability results are presented. The proposed registration method is proven to be more stable than the standard stereoscopic registration method and to be independent of the distance. Even when the user moves quickly, our developed system succeeds in producing stable three-point based registration. Therefore, our proposed methods can be considered as interesting alternatives to produce the registration in binocular augmented reality systems when only three points are available.

An RF CMOS active inductor with a novel loss compensation circuit network is proposed. Performance of this active inductor can be improved by adding a novel network, which simultaneously reduces parallel and series losses. Consequently, this technique not only increases Q value, inductance, and operating frequency, but also reduces power consumption and circuit complexity. Simulation results show that better performance indices can be achieved, such as minimum total equivalent loss of 1 mΩ, maximum Q value about 3E5, and inductance value from 20 nH to 45 nH in the RF range of 0.6 GHz to 1.6 GHz. Power dissipation is around 1.76 mW under 2.5 V dc supply voltage.

Structural learning algorithms are obtained by adding a penalty criterion (usually comes from the network structure) to the conventional criterion of the sum of squared errors and applying the backpropagation (BP) algorithm. This problem can be viewed as a constrained minimization problem. In this paper, we apply the Lagrangian differential gradient method to the structural learning based on the backpropagation-like algorithm. Computational experiments for both artificial and real data show that the improvement of generalization performance and the network optimization are obtained applying the proposed method.

Compressed video bitstream is sensitive to errors that may degrade the reconstructed images severely even the bit error rate is small. One approach to combat the impact of error is error concealment at the decoder without increasing the bit rate and changing the encoder. We propose motion vector based error concealment algorithms to recover the motion vector per pixel instead of that per block according to the relation of neighboring motion vectors. The displacement per pixel can be estimated more accurately by using the tendency of neighboring motion vectors. Besides, we use not only the relation among motion vectors, but also the pixels. The pixels of the error block are divided into different parts according to their consistency with neighboring blocks and the displacement at each pixel of these parts is interpolated by relative motion vectors. From simulation results, the proposed motion vector based methods provide better reconstruction quality for damaged images than other methods.

Virtual reality system is one of the most useful tools for investigating the characteristics of human perception in dynamic visual environment because we can easily and appropriately manipulate parameters of three-dimensional stimuli of vision in accordance with our purpose. In the present study we examined how the brain processes local stimuli during the global sensation of self-motion (vection) in view of temporal information processing -- perceptual latency -- with temporal order judgment task. In Experiment 1 we demonstrated that the targets in the left visual field were perceived prior to those in the right visual field when an observer stared at rightward optokinetic stimuli or perceived self-motion leftward, and vice versa. Especially at 16.0 deg of target eccentricity the biases were much larger with the continuous exposure of optokinetic stimuli than with their intermittent exposure; the former compelled observers to perceive self-motion and the latter hardly did. In Experiment 2 we examined the relationship between the occurrence of vection and temporal order judgments as the exposure duration of optokinetic stimuli was fixed between conditions, and showed that the biases were larger when vection occurred than when it did not. In Experiment 3 we showed that the biases were not modulated by the speed of optokinetic stimuli and not related with the speed of perceived self-motion. This phenomenon can be explained based on exogenous components of attention, the shift of the reference frame for determining the order in which objects come into awareness and imbalance between hemispheric activities. The mechanism is ecologically reasonable in that it allows us to be aware of the incoming events as soon as possible and to avoid any dangerous situations.

This paper takes full advantage of polarimetric scattering parameters and total power to classify polarimetric SAR image data. The parameters employed here are total power, polarimetric entropy, and averaged alpha angle (alphabar). Since these parameters are independent each other and represent all the scattering characteristics, they seem to be one of the best combinations to classify Polarimetric Synthetic Aperture Radar (POLSAR) images. Using unsupervised classification scheme with iterative Maximum Likelihood classifier, it is possible to decompose multi-look averaged coherency matrix with complex Wishart distribution effectively. The classification results are shown using Pi-SAR image data set comparing with other representative methods.

In this letter, we investigate the path length priority effect of existing just-enough-time (JET) scheme for optical burst switching (OBS) in the multiple hop network environments. And, we propose a novel hop-by-hop priority increasing (HPI) scheme using the input fiber delay lines (FDLs) at each node. Simulation results showed that the proposed FDL/delayed reservation (DR) with HPI scheme can avoid the path length priority effect and enhance the end-to-end throughput in multiple hop network environments.

For an additive white Gaussian noise (AWGN) channel, a performance evaluation of parallel concatenated turbo trellis-coded modulation (turbo TCM) using bit-interleavers is reported. By obtaining weight distribution, the performance is evaluated by using a union bound method. Comparison between the result of evaluated performance and simulation results is shown, and the usefulness of the evaluated performance is shown. An optimum code and an optimum mapping are sought. The result of the optimum code with the optimum mapping is a new interleaver size N dependency which is proportional to N-3. It is better than the interleaver size dependency for Benedetto code with the natural mapping which is proportional to N-1. The reasons why these dependencies can happen are also discussed.

We propose a new method to recover scene points from a single calibrated view using a subset of distances among the points. This paper first introduces the problem and its relationship with the perspective n point problem. Then the number of distances required to uniquely recover scene points are explored. The result is then developed into a practical vision algorithm to calculate the initial points' coordinates using distance constraints. Finally SQP (Sequential Quadratic Programming) is used to optimize the initial estimations. It can minimize a cost function defined as the sum of squared reprojection errors while keeping the specified distance constraints strictly satisfied. Both simulation data and real scene images have been used to test the proposed method, and good results have been obtained.

A new inter-client synchronization framework employing a server-client coordinated adaptive playout and error control toward one-to-many (i.e., multicast) media streaming is discussed in this paper. The proposed adaptive playout mechanism controls the playout speed of audio and video by adopting the time-scale modification of audio. Based on the overall synchronization status as well as the buffer occupancy level, the playout speed of each client is manipulated within a perceptually tolerable range. By coordinating the playout speed of each client, the inter-client synchronization with respect to the target presentation time is smoothly achieved. Furthermore, RTCP-compatible signaling between the server and group-clients is performed to achieve the inter-client synchronization and error recovery, where the exchange of controlling message is restricted. Simulation results show the performance of the proposed multicast media streaming framework.

We propose a novel mobility reduction cancellation technique for an OTA (Operational Transconductance Amplifier). The proposed technique can be easily realized by using conventional OTAs. The proposed OTAs have good linearity. The simulation results show that the THD is less than 1% for 1.8 Vp-p at 3 V supply voltage.

This letter shows the performance comparisons of several different rate scheduling schemes for non-real time data service over the uplink of burst switching-based direct sequence code division multiple access (DS/CDMA) system to support the integrated voice/data service. The closed-form solution of optimal scheduling formulation, which minimizes average transmission delay when all of the active data users are transmitting simultaneously, is presented and mathematical analyses with other rate scheduling schemes, which provide efficiency criterion of transmission delay for rate scheduling schemes, are performed. Numerical results show the analyses explicitly.

Multi-Carrier Code Division Multiple Access (MC-CDMA) is one of candidates for the next generation wireless communication systems. In an uplink, the MC-CDMA system suffers from the different access timing (asynchronous transmission), the different fading, and the different frequency offsets of each active user. In this paper we analyze the effects of the frequency offset compensation with MMSE-MUD (minimum mean square error based multi-user detection) for MC-CDMA in a quasi-synchronous uplink. We consider the MC-CDMA system with two subcarrier mapping schemes, the continuous mapping scheme and the discrete mapping scheme. From our theoretical analysis and computer simulation, we show that the MMSE-MUD can compensate the different frequency offsets among users. We also show that the MMSE-MUD significantly improves the bit error rate (BER) for the MC-CDMA system with the continuous mapping scheme.

An information retrieval (IR) system with query expansion on a low-cost high-performance PC cluster environment is implemented. We study how query performance is affected by query expansion and two declustering methods using two standard Korean test collections. According to the experiments, the greedy method shows about 20% enhancement overall when compared with the lexical method.

The threshold voltage mismatch of FD (Fully depleted) SOI (Silicon on insulator) devices have been studied. Floating body MOSFETs operating at high drain voltage show a large mismatch in the threshold voltage compared with body-tied MOSFETs. Those experimental data under different drain voltages indicate that both floating body effect and DIBL (Drain induced barrier lowering) are involved in the threshold voltage mismatch of floating body MOSFETs.

In General Packet Radio Service (GPRS), combined mobility management is defined to efficiently perform both GSM and GPRS mobility management in a combined manner. In this letter, an enhanced scheme for combined mobility management based on a new mobile station (MS) state model is proposed. The steady state probabilities of the proposed MS state model are derived and the performance of the proposed scheme is analyzed. The results show that the proposed scheme outperforms the conventional scheme, especially for low mobility MSs.

Applications for transforming money or personal information are increasingly common on the Internet and in mobile communications. These applications require user authentication for confirming legal users. One-time password authentication methods change the verifier every time by sending the present verifier along with the next verifier. However, such methods risk attacks because those protocols use two verifiers every session. The SAS (Simple And Secure password authentication protocol) is a one-time password authentication method that the method uses a hash function five times, but it requires high overhead on low spec machines. In this paper, we propose a new method, SAS-2, which reduces overhead of hash function adaptation by 40%. This method has a mutual authentication phase, which maintains synchronous data communications in its authentication procedure. Moreover, SAS-2 can be applied to key-free systems.