This paper studies the robustness of message masking communication over noisy channels using modified chaotic systems. First, the modified chaotic systems are introduced with a higher capability of transmitting messages than typical chaotic systems. Then, assuming an ideal channel, the chaotic message masking scheme is derived which achieves asymptotic convergence or dead-beat performance for recovering messages. Next, considering the case of noisy channels, an H∞ performance and an L2-gain optimal noise rejection are achieved by solving linear matrix inequality (LMI) problems. Furthermore, the ultimate bound of synchronization error and recovered message error can be adjusted by both design gains and the system parameter of the modified chaos. Using the proposed method, the bit-error-ratio and noise tolerance are improved. Finally, numerical simulations and DSP experiments are carried out to verify the theoretical derivations.

In this paper a newly designed internally-coupled asymmetric stepped-impedance resonator (SIR) bandpass filter (BPF) is proposed. The asymmetric SIR structure not only can effectively reduce the circuit size but also can provide two flexibly tunable transmission zeros near the lower and upper passband edges. The first transmission zero is due to the series resonance of the quarter-wavelength open stepped-impedance stub, and the second one is produced by anti-parallel coupling between adjacent SIRs. The proposed BPF was fabricated and simulated using the commercial software HFSS, and agreement between the measured and simulated results was observed. A 0.9-dB insertion loss and a shape factor of 3.6 were achieved in the passband, thus indicating that the proposed filter structure is of practical value.

The effect of the power/ground plane on the through-hole signal via is analyzed in a viewpoint of a band-stop filter. When the through-hole signal via passes through the power/ground plane, the return current path discontinuity of the through-hole signal via occurs due to the high impedance of the power/ground plane. Since the high impedance is produced by the power/ground plane resonance, it acts as a band-stop filter, which is connected to the signal trace in series. Therefore, the power/ground plane filters off its resonance frequency component by absorbing and reflecting from the signal on the through-hole signal via, and consequently the signal distortion, the power/ground plane noise voltage, and the consequent radiated emission occur. With S-parameter and TDR-TDT measurements, the band-stop effect of the power/ground plane on the through-hole signal via is confirmed. And then, this analysis is applied to the clock transmission through the through-hole signal via to obtain the clearer confirmation. The measurements of the distorted clock waveforms, the induced power/ground plane noise voltages, and the radiated emissions depending on the power/ground plane impedance around the through-hole signal via are shown.

In recent years, digital watermarking has become a popular technique for labeling digital images by hiding secret information which can protect the copyright. The goal of this paper is to develop a DCT-based watermarking algorithm for low power and high performance. Our energy-efficient technique focuses on reducing computation required on block-based permutation. Instead of using spacial coefficients proposed by Hsu and Wu's algorithm [1], we use DCT coefficients to pair blocks directly. The approach is implemented by C language and estimated power dissipation using Wattch toolset. The experimental results show that our approach not only reduces 99% energy consumption of pairing mechanism, but also increase the PSNR by 0.414 db for the best case. Moreover, the proposed approach is robust to a variety of signal distortions, such as JPEG, image cropping, sharpening, blurring, and intensity adjusting.

With the rapid spread of information and ubiquitous access of browsers, flash crowds, a sudden, unanticipated surge in the volume of request rates, have become the bane of many Internet websites. This paper models and presents FCAN, an adaptive network that dynamically optimizes the system structure between peer-to-peer (P2P) and client-server (C/S) configurations to alleviate flash crowds effect. FCAN constructs P2P overlay on cache proxy server layer to distribute the flash traffic from origin server. It uses policy-configured DNS redirection to route the client requests in balance, and adopts strategy load detection to monitor and react the load changes. Our preliminary simulation results showed that the system is overall well behaved, which validates the correctness of our design.

Supporting Quality of Service (QoS) over the Internet is a very important issue and many mechanism have been already devised or are under way towards achieving this goal. One of the most important approaches is the class-based architecture, which provides a scalable mechanism for QoS support in a TCP/IP network. Class-based service differentiation can be realized without resource reservation, admission control and traffic policing. However, the resulting services are only relative. While it is, in principle, not feasible to provision for absolute guarantees without admission control and/or traffic policing, such a service can be reasonably well emulated using adaptive rate allocation at the link scheduler of routers. In this paper, we propose mechanism for link scheduler of router that achieve emulated absolute and other relative guarantees using dynamic weighted fair queueing (DWFQ) combining with class packet dropping. The weights of DWFQ are frequently adjusted to current load conditions and based on prediction of realistic class traffic. These mechanisms can realize many approaches to QoS guarantees and class-based differentiation.

This paper presents an approach to specification-based testing of concurrent programs with representative test sequences generated from Statecharts. Representative test sequences are a subset of all possible interleavings of concurrent events that define the behaviors of a concurrent program. Because a program's correctness may be determined by checking whether a program implemented all behaviors in its specification or not, the program can be regarded as being correct if it can supply an alternative execution that has the same effects as the program's behavior with each representative test sequence. Based on this observation, we employ each representative test sequence as a seed to generate an automaton that accepts its equivalent sequences to reveal the same behavior. In order to effectively test a concurrent program, the automaton such generated accepts all sequences equivalent to the representative test sequence and it is used to control test execution. This paper describes an automated process of generating automata from a Statecharts specification and shows how the proposed approach works on Statecharts specifications through some examples.

In advanced ASIC/SoC physical designs, interconnect parasitic extraction is one of the important factors to determine the accuracy of timing analysis. We present a formula-based method to efficiently extract interconnect capacitances of interconnects with dummy fills for VLSI designs. The whole flow is as follows: 1) in each process, obtain capacitances per unit length using a 3-D field solver and then create formulas, and 2) in the actual design phase, execute a well-known 2.5-D capacitance extraction. Our results indicated that accuracies of the proposed formulas were almost within 3% error. The proposed formula-based method can extract interconnect capacitances with high accuracy for VLSI circuits. Moreover, we present formulas to evaluate the effect of dummy fills on interconnect capacitances. These can be useful for determining design guidelines, such as metal density before the actual design, and for analyzing the effect of each structural parameter during the design phase.

A differential detection Space-Time Block Code (STBC) is proposed with a high transmission rate, allowing a trade-off between diversity and multiplexing gain with low encoding and decoding complexity. The proposed method offers multiplexing gain by doubling the transmission rate for three and four transmission antennas. Computer simulations demonstrate that the proposed STBC can achieve a 5.8 dB Eb/N0 gain at BER = 10-3 compared with a conventional differential detection STBC for four transmission and two receiving antennas.

This paper presents a test input data compression technique, Selective Low-Care Coding (SLC), which can be used to significantly reduce input test data volume as well as the external test channel requirement for multiscan-based designs. In the proposed SLC scheme, we explored the linear dependencies of the internal scan chains, and instead of encoding all the specified bits in test cubes, only a smaller amount of specified bits are selected for encoding, thus greater compression can be expected. Experiments on the larger benchmark circuits show drastic reduction in test data volume with corresponding savings on test application time can be indeed achieved even for the well-compacted test set.

Recently, system level design languages (SLDL), which can describe both hardware and software aspects of the design, are receiving attention. Mixed-signal extensions of SLDL enable current discrete-oriented SLDLs to describe and simulate not only digital systems but also digital-analog mixed-signal systems. The synchronization between discrete and continuous behaviors is widely regarded as a critical part in the extensions. In this paper, we present an event-driven synchronization mechanism for both timed and untimed system level designs through which discrete and continuous behaviors are synchronized via AD events and DA events. We also demonstrate how the synchronization mechanism can be incorporated into the kernel of SLDL, such as SpecC. In the extended kernel, a new simulation cycle, the AMS cycle, is introduced. Three case studies show that the extended SpecC-based system level design environment using our synchronization mechanism works well with timed/untimed mixed-signal system level description.

The analog IC technology, might sound old-fashioned, is still important for the future wireless systems such as 4G cellular phone systems, broadband wireless networkings, and wireless sensor networkings. The analog features and issues of the scaled CMOS transistor, the basic issue and the technology trend for the ADC as an important building block of wires systems, and the feature of the digital RF architecture proposed recently are reviewed and discussed. Higher speed and lower power consumption are expected for low SNR systems along with the further technology scaling. However, the high SNR system is not realized easily due to a decrease of signal voltage. One of the important technology trends is the digitalization of RF signal to realize the system flexibility, robustness, area shrinking, and TAT shortening.

A planar composite right/left-handed leaky wave antenna which operates at W-band is fabricated and its backward to forward beam scanning operation including broadside direction is confirmed experimentally. The scanning angle from 61 to 114 degrees with a frequency scanning range of 76 to 79 GHz is achieved.

A new video text localization approach is proposed. First, some pre-processing techniques, including color space conversion and histogram equalization, are applied to the input video frames to obtain the enhanced gray-scale images. Features are then extracted using wavelet transform to represent the texture property of text regions. Next, an unsupervised fuzzy c-means classifier is performed to discriminate candidate text pixels from background. Effective operations such as the morphological dilation operation and logical AND operation are applied for locating text blocks. A projection analysis technique is then employed to extract text lines. Finally, some geometric heuristics are used to remove noise regions and refine location of text lines. Experimental results indicate that the proposed approach is superior to other three representative approaches in term of total detection rate.

Activity patterns of metabolic subnetworks, each of which can be regarded as a biological function module, were focused on in order to clarify biological meanings of observed deviation patterns of gene expressions induced by various chemical stimuli. We tried to infer association structures of genes by applying the multivariate statistical method called graphical Gaussian modeling to the gene expression data in a subnetwork-wise manner. It can be expected that the obtained graphical models will provide reasonable relationships between gene expressions and macroscopic biological functions. In this study, the gene expression patterns in nematodes under various conditions (stresses by chemicals such as heavy metals and endocrine disrupters) were observed using DNA microarrays. The graphical models for metabolic subnetworks were obtained from these expression data. The obtained models (independence graph) represent gene association structures of cooperativities of genes. We compared each independence graph with a corresponding metabolic subnetwork. Then we obtained a pattern that is a set of characteristic values for these graphs, and found that the pattern of heavy metals differs considerably from that of endocrine disrupters. This implies that a set of characteristic values of the graphs can representative a macroscopic biological meaning.

A hybrid evolutionary neuro-fuzzy system (HENFS) is proposed in this paper, where the weighted Gaussian function (WGF) is used as the membership function for improved premise construction. With the WGF, different types of the membership functions (MFs) can be accommodated in the rule base of HENFS. A new hybrid algorithm of random optimization (RO) algorithm incorporated with the least square estimation (LSE) is presented. Based on the hybridization of RO-LSE, the proposed soft-computing approach overcomes the disadvantages of other widely used algorithms. The proposed HENFS is applied to chaos time series identification and industrial process modeling to verify its feasibility. Through the illustrations and comparisons the impressive performances for unknown system identification can be observed.

Software inspection is a widely acknowledged effective quality improvement method in software development by detecting defects involved in software artifacts and removing them. In research on software inspection, constructing computer supported inspection systems is a major topic in the field. A lot of systems have been reported. However few inspection support systems for model diagrams, especially UML diagrams, have been emerged. We identified four key requirements an inspection support system for UML diagrams should have. They are as follows: 1) direct annotations are given to model diagrams, 2) version management is provided so that evolution of artifacts can be managed, 3) the whole inspection process should be supported, 4) horizontal and vertical readings are supported. This paper describes design and implementation of our inspection support system for UML diagrams to realize the four requirements.

An improved algorithm for fast motion estimation based on the block matching algorithm (BMA) is presented for use in a block-based video coding system. To achieve enhanced motion estimation performance, we propose an adaptive search pattern length for each iteration for the current macro block (MB). In addition, search points that must be checked are determined by means of directional information from the error surface, thus reducing intermediate searches. The proposed algorithm is tested with several sequences and excellent performance is verified.

The Japan Aerospace Exploration Agency (JAXA) plans to launch a geostationary satellite called Engineering Test Satellite VIII (ETS-VIII) in FY 2006. In this paper, a microstrip line array antenna, which has a very simple structure, is introduced to radiate a circularly polarized wave aiming at ETS-VIII applications. This antenna consists of a triangular conducting line with its vertexes rounded off, located above a ground plane, with a gap on one of its side to produce a circular polarization. The proposed antenna is analyzed by numerical simulations for a single element as well as for a three elements array configuration and the possibility of beam-switching in the azimuth space is experimentally confirmed in the latter case. It is found that by properly feeding the elements constituting the array antenna, for an elevation angle El = 48in Tokyo area, three beams are created in the conical-cut direction with a minimum gain more than 6.6 dBic and an axial ratio less than 3 dB.

Motivated by the result in [12] we present a new block iterative multiuser detection algorithm utilizing the constant modulus (CM) property of data symbols. The proposed iterative detector is developed based on a constrained least square (LS) cost function and CM projection. It can be seen as an extension of least squares constant modulus algorithm [1] in a sense that it minimizes the CM and the LS cost functions iteratively. Simulation study shows that even for a reasonably small number of symbols, say around 100 received symbols, the proposed iterative detector approaches the performance of ideal MMSE detector and considerably outperforms the conventional blind detectors, such as subspace blind method [7] or MOE detector [5].