The All-Pairs Shortest Paths (APSP) problem is a graph problem which can be solved by a three-nested loop program. The Cell Broadband Engine (Cell/B.E.) is a heterogeneous multi-core processor that offers the high single precision floating-point performance. In this paper, a solution of the APSP problem on the Cell/B.E. is presented. To maximize the performance of the Cell/B.E., a blocked algorithm for the APSP problem is used. The blocked algorithm enables reuse of data in registers and utilizes the memory hierarchy. We also describe several optimization techniques for effective implementation of the APSP problem on the Cell/B.E. The Cell/B.E. achieves the performance of 8.45 Gflop/s for the APSP problem by using one SPE and 50.6 Gflop/s by using six SPEs.

We propose a dimension reduction algorithm for the receiver of the downlink of direct-sequence code-division multiple access (DS-CDMA) systems in which both the transmitters and the receivers employ antenna arrays of multiple elements. To estimate the high order channel parameters, we develop a layered architecture using dimension-reduced parameter estimation algorithms to estimate the frequency-selective multipath channels. In the proposed architecture, to exploit the space-time geometric characteristics of multipath channels, spatial beamformers and constrained (or unconstrained) temporal filters are adopted for clustered-multipath grouping and path isolation. In conjunction with the multiple access interference (MAI) suppression techniques, the proposed architecture jointly estimates the direction of arrivals, propagation delays, and fading amplitudes of the downlink fading multipaths. With the outputs of the proposed architecture, the signals of interest can then be naturally detected by using path-wise maximum ratio combining. Compared to the traditional techniques, such as the Joint-Angle-and-Delay-Estimation (JADE) algorithm for DOA-delay joint estimation and the space-time minimum mean square error (ST-MMSE) algorithm for signal detection, computer simulations show that the proposed algorithm substantially mitigate the computational complexity at the expense of only slight performance degradation.

We propose an automatic generative method for stylus style CG as automatic generative method for non-photorealistic CG.

In recent years, the space-time block coding (STBC) method has attracted attention to provide transmission diversity in mobile communication systems. Although the STBC method is very effective in slow fading environments, its performance in fast fading environments has yet to be clearly verified. In this paper we propose a railway radio communication system using space-time coding in cooperation with two base stations. Here, we considered the differential STBC (D-STBC) method in railway communication system to overcome difficulties caused by the fast fading environment. We have compared the performance of STBC and D-STBC method where there is frequency offset between two base stations. Moreover, we have presented the simulation result of overall performance of the system including frequency offset and transmission time delay when operating D-STBC method. The overall evaluation on this paper shows that the D-STBC method is suitable for realizing highly reliable railway communication systems.

We propose two vertical handoff schemes for cellular network and wireless local area network (WLAN) integration: integrated service-based handoff (ISH) and integrated service-based handoff with queue capabilities (ISHQ). Compared with existing handoff schemes in integrated cellular/WLAN networks, the proposed schemes consider a more comprehensive set of system characteristics such as different features of voice and data services, dynamic information about the admitted calls, user mobility and vertical handoffs in two directions. The code division multiple access (CDMA) cellular network and IEEE 802.11e WLAN are taken into account in the proposed schemes. We model the integrated networks by using multi-dimensional Markov chains and the major performance measures are derived for voice and data services. The important system parameters such as thresholds to prioritize handoff voice calls and queue sizes are optimized. Numerical results demonstrate that the proposed ISHQ scheme can maximize the utilization of overall bandwidth resources with the best quality of service (QoS) provisioning for voice and data services.

Continuous phase modulation (CPM) is a non-linear modulation technique whose power and bandwidth efficiency make it an attractive choice for mobile communication systems. Current research has focused on devising encoding rules for using CPM over multiple-input multiple-output (MIMO) systems in order to obtain the improved bit error rate (BER) and high data rates promised by MIMO technology. In this paper, optimal and suboptimal non-coherent receivers for a class of CPM signals called orthogonal space-time CPM (OST-CPM) are derived under a quasi-static fading channel assumption. The performance of these receivers is characterized and shown to achieve the same diversity order as that of the corresponding optimal coherent receiver.

The polarization dependence of the resonance wavelength of long period fiber gratings (LPFGs) that employ the photoelastic effect is investigated based on a simple model. The proposed model for estimating the birefringence of these LPFGs provides a good explanation of the experimental results.

Time variation within an OFDM symbol causes inter-carrier interference (ICI). In this letter, frequency-domain partial response coding (PRC) is investigated to reduce ICI in the Alamouti SFBC-OFDM system. Based on the expression of the ICI power in the SFBC-OFDM system with PRC, the near-optimal weights of PRC are derived. Simulation results show that the PRC scheme can reduce ICI effectively.

The electromagnetic fields emitted from an electrostatic discharge (ESD) event occurring between charged metals cause seriously damage high-tech equipment. In order to clarify the generation mechanism of such ESD fields and also to reduce them, we previously proposed a finite-difference time-domain (FDTD) algorithm based on a delta-gap feeding method and a frequency dispersion characteristic formula (Naito's formula) of ferrite material for simulating the ESD fields due to a spark between the charged metals with ferrite core attachment. In the present study, by integrating the above FDTD algorithm and a spark-resistance formula, we simulated both of the ESD itself and the resultant fields for the metal bars with ferrite core attachment, and demonstrated that the core attachment close to the spark gap suppresses the magnetic field level. This finding was also validated via 6-GHz wide-band measurement of the magnetic near-field.

An integral equation approach with a new solution procedure using moment method (MoM) is applied for the computation of coupled currents on the surface of a printed dipole antenna and inside its high-permittivity three-dimensional dielectric substrate. The main purpose of this study is to validate the accuracy and reliability of the previously proposed MoM procedure by authors for the solution of a coupled volume-surface integral equations system. In continuation of the recent works of authors, a mixed-domain MoM expansion using Legendre polynomial basis function and cubic geometric modeling are adopted to solve the tensor-volume integral equation. In mixed-domain MoM, a combination of entire-domain and sub-domain basis functions, including three-dimensional Legnedre polynomial basis functions with different degrees is utilized for field expansion inside dielectric substrate. In addition, the conventional Rao-Wilton-Glisson (RWG) basis function is employed for electric current expansion over the printed structure. The accuracy of the proposed approach is verified through a comparison with the MoM solutions based on the spectral domain Green's function for infinitely large substrate and the results of FDTD method.

Placing a guard trace next to a signal line is the conventional technique for reducing the common-mode radiation from a printed circuit board. In this paper, the suppression of common-mode radiation from printed circuit boards having guard traces is estimated and evaluated using the imbalance difference model, which was proposed by the authors. To reduce common-mode radiation further, a procedure for designing a transmission line with guard traces is proposed. Guard traces connected to a return plane through vias are placed near a signal line and they decrease a current division factor (CDF). The CDF represents the degree of imbalance of a transmission line, and a common-mode electromotive force depends on the CDF. Thus, by calculating the CDF, we can estimate the reduction in common-mode radiation. It is reduced not only by placing guard traces, but also by narrowing the signal line to compensate for the variation in characteristic impedance due to the guard traces. Experimental results showed that the maximum reduction in common-mode radiation was about 14 dB achieved by placing guard traces on both sides of the signal line, and the calculated reduction agreed with the measured one within 1 dB. According to the CDF and characteristic impedance calculations, common-mode radiation can be reduced by about 25 dB while keeping the characteristic impedance constant by changing the gap between the signal line and the guard trace and by narrowing the width of the signal line.

Ball Grid Array packages in which I/O pins are arranged in a grid array pattern realize a number of connections between chips and a printed circuit board, but it takes much time in manual routing. We propose a fast routing method for 2-layer Ball Grid Array packages that iteratively modifies via assignment. In experiments, in most cases, via assignment and global routing on both of layers in which all nets are realized and the violation of wire congestion on layer 1 is small are speedily obtained.

The vacuum sealing process with a base vacuum of 10-5 Torr is adopted to minimize the residual impurity gas. The address and sustain discharges in the 42-in PDP prepared by the vacuum-sealing process are observed by using the ICCD. As a result, the ICCD observation illustrates that thanks to the reduction of the impurity level by the vacuum-sealing process, the surface and plate-gap discharges are initiated and extinguished very fast and the corresponding IR emissions are also intensified.

Security protocol provides communication security for the internet. One of the important features of it is authentication with key exchange. Its correctness is a requirement of the whole of the communication security. In this paper, we introduce three attack models realized as their attack scenarios, and provide an authentication-protocol checker for applying three attack-scenarios based on the models. We also utilize it to check two popular security protocols: Secure SHell (SSH) and Secure Socket Layer/Transport Layer Security (SSL/TLS).

A novel DC-to-960 MHz impulse radio ultra-wideband (IR-UWB) transceiver based on threshold detection technique is developed. It features a digital pulse-shaping transmitter, a DC power-free pulse discriminator and an error-recovery phase-frequency detector. The developed transceiver in 90 nm CMOS achieves the lowest energy consumption of 2.2 pJ/bit transmitter and 1.9 pJ/bit receiver at 100 Mbps in the UWB transceivers.

When the joint source-channel (JSC) decoder is used for source coding over noisy channels, the JSC decoder may invent errors even though the received data is not corrupted by the channel noise, if the JSC decoder assumes the channel was noisy. A novel encoder algorithm has been recently proposed to improve the performance of the communications system under this situation. In this letter, we propose another algorithm based on conditional entropy-constrained vector quantizer to further improve the encoder. The algorithm proposed in this letter significantly improves the performance of the communications system when the hypothesized channel bit error rate is high.

This paper develops a complete architecture for constant false alarm rate (CFAR) detection based on a goodness-of-fit (GOF) test. This architecture begins with a logarithmic amplifier, which transforms the background distribution, whether Weibull or lognormal into a location-scale (LS) one, some relevant properties of which are exploited to ensure CFAR. A GOF test is adopted at last to decide whether the samples under test belong to the background or are abnormal given the background and so should be declared to be a target of interest. The performance of this new CFAR scheme is investigated both in homogeneous and multiple interfering targets environment.

We describe the applicability of photonic crystal fiber (PCF) with an enlarged effective area Aeff to a distributed Raman amplification (DRA) transmission. We investigate the DRA transmission performance numerically over a large Aeff PCF taking account of the signal-to-noise ratio (SNR) improvement RSNR in the S, C, and L bands. We show that an RSNR of 3 dB can be expected by utilizing DRA with a maximum pump power of 500 mW when the Aeff of the PCF is 230 µm2.

Several scheduling algorithms have been proposed for the downlink of a Code Division Multiple Access (CDMA) system with High Data Rate (HDR). Modified Largest Weighted Delay First (M-LWDF) scheduling algorithm selects a user according to the user current channel condition, user head-of-line packet delay and user Quality of Service (QoS) requirement. Proportional Fair (PF) scheduling algorithm has also been proposed for CDMA/HDR system and it selects a user according to the ratio of the user current channel rate and the user average channel rate, which provides good performance in terms of fairness. However, when variable bit rate (VBR) traffic is considered under different channel conditions for each user, both schedulers' performance decrease. M-LWDF scheduler can not guarantee the QoS requirement to be achieved and PF scheduler can not achieve a good fairness among the users. In this work, we propose a new scheduling algorithm to enhance M-LWDF and PF schedulers performance. Proposed scheduler selects a user according to the user input traffic characteristic, user current channel condition and user QoS requirement, which consists of a delay value with a maximum violation probability. We consider the well-known effective bandwidth expression, which takes into account the user QoS requirement and the user input traffic characteristics, to select a user to be scheduled. Properties of the proposed scheduling algorithm are investigated through simulations with constant bit rate (CBR) and VBR flows and performance comparisons with M-LWDF and PF schedulers. The results show a better performance of the proposed scheduler compared with M-LWDF and PF schedulers.

Internet routers need to classify incoming packets quickly into flows in order to support features such as Internet security, virtual private networks and Quality of Service (QoS). Packet classification uses information contained in the packet header, and a predefined rule table in the routers. Packet classification of multiple fields is generally a difficult problem. Hence, researchers have proposed various algorithms. This study proposes a multi-dimensional encoding method in which parameters such as the source IP address, destination IP address, source port, destination port and protocol type are placed in a multi-dimensional space. Similar to the previously best known algorithm, i.e., bitmap intersection, multi-dimensional encoding is based on the multi-dimensional range lookup approach, in which rules are divided into several multi-dimensional collision-free rule sets. These sets are then used to form the new coding vector to replace the bit vector of the bitmap intersection algorithm. The average memory storage of this encoding is θ (LNlog N) for each dimension, where L denotes the number of collision-free rule sets, and N represents the number of rules. The multi-dimensional encoding practically requires much less memory than bitmap intersection algorithm. Additionally, the computation needed for this encoding is as simple as bitmap intersection algorithm. The low memory requirement of the proposed scheme means that it not only decreases the cost of packet classification engine, but also increases the classification performance, since memory represents the performance bottleneck in the packet classification engine implementation using a network processor.