This paper describes the formula for dynamic power dissipation of a track/hold circuit as a function of the input frequency, the input amplitude, the sampling frequency, the track/hold duty cycle, the power supply voltage and the hold capacitance for a sinusoidal input.

We examine the detection of coded hybrid direct-sequence frequency-hopped spread-spectrum signals in the presence of narrowband interference. Since blind interference suppression requires a reliable estimate of the data, while at the same time data decoding requires interference suppression, we advocate an iterative ("turbo") detection scheme whereby information is exchanged between the interference suppressor and the soft-input soft-output decoder. Several suppression schemes are examined and compared. Simulation results show that this new scheme is robust, i.e., exhibits good performance under a modicum of assumptions on the interference structure. Turbo codes and convolutional codes are compared, showing that the former perform better.

The high accuracy which is necessary for modern process simulation often requires the use of Monte-Carlo ion implantation simulation methods with the disadvantage of very long simulation times especially for three-dimensional applications. In this work a new method for an accurate and CPU time efficient three-dimensional simulation of ion implantation is suggested. The approach is based on a combination of the algorithmic capabilities of a fast analytical and the Monte-Carlo simulation method.

The individually normalized least mean square (INLMS) algorithm is proposed as an adaptive algorithm suitable for the fixed point processing. The convergence property of the INLMS algorithm, however, is not yet analyzed enough. This paper first derives an equation describing the convergence property by exploiting the technique of expressing the INLMS algorithm as a first order infinite impulse response (IIR) filter. According to the equation derived thus, the decreasing process of the estimation error is represented as the response of another IIR filter expression. By using the representation, this paper second derives the convergence condition of the INLMS algorithm as the range of the step size making a low path filter of the latter IIR filter. This paper also derives the step size maximizing the convergence speed as the maximum coefficient of the latter IIR filter and finally clarifies the range of the step size recommended in the practical system design.

We consider a wait-free linearizable implementation of shared objects on a distributed message-passing system. We assume that the system provides each process with a local clock that runs at the same speed as global time and that all message delays are in the range [d-u,d] where d and u (0< u d) are constants known to every process. We present four wait-free linearizable implementations of read/write registers on reliable and unreliable broadcast models. We also present two wait-free linearizable implementations of general objects on a reliable broadcast model. The efficiency of an implementation is measured by the worst-case response time for each operation of the implemented object. Response times of our wait-free implementations of read/write registers on a reliable broadcast model is better than a previously known implementation in which wait-freedom is not taken into account.

In this paper, we propose an effective SOI yield engineering methodology by practical usage of 2D simulations. Process design for systematic yield of Fully-Depleted SOI MOSFET requires specific consideration of floating-body effects and parasitic channel leakage currents. The influence of varied SOI layer thickness to such phenomena is also complicated and substantial. Instead of time-consuming 3D simulators, 2D simulators are used to optimize the process considering these effects in acceptable turn around time. Our methodology is more effective in future scaled-down process with decreased SOI layer thickness.

The use of intelligent agents is on the rise, fueled by the unprecedented growth in the Internet and web based applications. Consequently, agent-oriented software is becoming large and complex. To support a systematic development of such software, an agent-oriented software development methodology is necessary. This paper focuses on the modeling phase of agent-oriented software life cycle and, presents an approach for agent modeling consisting of Agent Elicitation, Intra, and Inter Agent modeling methods. Agent Elicitation deals with identifying and extracting agents from "classes" in the real world. Intra Agent Modeling involves expressing agent characteristics - Goal, Belief, Plan and Capability - whereas, Inter Agent modeling incorporates agent mobility and communication in a multi-agent system.

Recent development of compact and powerful portable computers and mobile phones and proliferation of the Internet will enable mobile multimedia communications. From the viewpoint of implementing multimedia services into mobile communications, it allows us to predict that traffic characteristics of mobile networks change. For planning, designing, and operating mobile multimedia networks, it is important to investigate traffic models which take the effect of multimedia services into consideration. This paper investigates population of active users in a micro-cell and proposes a traffic model for mobile multimedia networks. This model describes a population process of active users in a micro-cell in diffusion model, and its characteristics include self-similarity and activity of mobility. We also made an evaluation of network performance by using simulation, in order to show that characteristics of the proposed traffic model have impact on planning and designing networks.

This paper experimentally demonstrates the possibility of 2-Mbps data transmission using a 5-MHz bandwidth (chip rate of 4.096 Mcps) wideband DS-CDMA (W-CDMA) mobile radio link in frequency-selective multipath fading environments. To reduce the mobile station transceiver complexity, three-orthogonal code multiplexing with the spreading factor (SF) of 4 is employed. In such a small SF transmission, the increased multipath interference (MPI) significantly degrades the transmission performance. We consider two-branch antenna diversity reception and fast transmit power control (TPC) as well as channel coding to mitigate the influence of MPI. Laboratory experimental results show that the use of antenna diversity reception is significant and that the fast TPC improves the transmission performance. Furthermore, the impact of the fading maximum Doppler frequency, fD, and that of the channel coding interleaving size, Tint, on the achievable BER performance are also investigated.

In this paper the novel method of "weighted OFDM" is addressed. Different types of weighting factors (including Rectangular, Bartlett, Gaussian, Raised cosine, Half-sin and Shanon) are considered. The impact of weighting of OFDM on the peak-to-average power ratio (PAPR) is investigated by means of simulation and is compared for the above mentioned weighting factors. Results show that by weighting of the OFDM signal the PAPR reduces. Bit error performance of weighted multicarrier transmission over a multipath channel is also investigated. Results indicate that there is a trade off between PAPR reduction and bit error performance degradation by weighting.

The optimization of channel assignment in cellular mobile networks is an NP-complete combinatorial optimization problem. For any reasonable size network, only sub-optimal solutions can be obtained by heuristic algorithms. In this paper, six channel assignment heuristic algorithms are proposed and evaluated. They are the combinations of three channel assignment strategies and two cell ordering methods. What we found are (i) the node-color ordering of cells is a more efficient ordering method than the node-degree ordering; (ii) the frequency exhaustive strategy is more suitable for systems with highly non-uniformly distributed traffic, and the requirement exhaustive strategy is more suitable for systems with less non-uniformly distributed traffic; and (iii) the combined frequency and requirement exhaustive strategy with node-color re-ordering is the most efficient algorithm. The frequency spans obtained using the proposed algorithms are much lower than that reported in the literature, and in many cases are equal to the theoretical lower bounds.

In high-speed TDMA mobile communications, frequency-selective fading is a serious problem because a delay time difference between multipath signals is large in comparison with symbol duration. We have proposed a spatial-domain RAKE receiver using a multibeam adaptive antenna to reduce frequency-selective fading and to realize path-diversity. The multibeam adaptive antenna resolves multipath signals in the spatial domain, and combines array outputs. In this paper, we propose the application of MUSIC algorithm to estimation of the time delays of multipath signals to make the incident signals coincide with a common reference signal. Because the MUSIC algorithm can estimate the time delays accurately, the BER performance of the proposed scheme is improved. Furthermore, we propose weighting factors which easily realize the maximal-ratio combining.

A BSIM3v3 based ferroelectric memory field effect transistor (FEMFET) compact model for circuit simulation is presented. Its analytical approach is based on the MOS capacitor equations taking into account the influence of a ferroelectric polarization. The hysteresis behavior of the gate ferroelectric has been modeled by using the distribution function integral method (DFIM). The parameters for the presented simulations were extracted by measurements on MIS and MFIS structures.

A repeating watermarking technique based on visual secret sharing (VSS) scheme provides the watermark repeated throughout the image for avoiding the image cropping. In this paper, the watermark is divided into public watermark and secret watermark by using the VSS scheme to improve the security of the proposed watermarking technique. Unlike the traditional methods, the original watermark does not have to be embedded into the host image directly and, thus, it is hard to be detected or removed by the pirates or hackers. The retrieved watermark extracted from the watermarked image does not require the complete original image, but requires a secret watermark. Furthermore, the watermarking technique suits the watermark with an adaptive size of binary image for designing the watermarking system. The experimental results show that the proposed method can withstand the common image processing operations, such as filtering, lossy compression and the cropping attacking etc. The embedded watermark is imperceptible, and that the extracted watermark identifies clearly the owner's copyright.

A comprehensive analysis methodology allowing investigation of the RF performance of Si and strained Si:SiGe MOSFETs is presented. It is based on transient ensemble Monte Carlo simulation which correctly describes device transport, and employs a finite element solver to account for complex device geometries. Transfer characteristics and figures of merit for a number of existing and proposed RF MOSFETs are discussed.

This paper proposes a fast and simple adaptive algorithm for MMSE (Minimum Mean Square Error) adaptive array antenna or MMSE combining diversity. This algorithm can be implemented with as a small operation as LMS since it is based on VS-LMS (variable step size LMS) for which the step size is provided with a fixed profile. Computer simulation results show that the proposed algorithm has much better convergence behavior and BER performance than LMS.

In this work, distributed dynamic channel assignment strategies with violation to the reuse pattern using vehicular mobility information for highway microcellular environments are proposed. It is shown that, when vehicular mobility information is included in the acquisition channel policy, the outage probability degradation because of the use of channels with one violation to the reuse pattern is negligible. Also, it is shown that, using different moving direction strategies it is possible to control the tradeoff between capacity and quality of service. The local packing algorithm (LP), was modified to allow the use of two different moving direction strategies with violation to the reuse pattern, resulting the VDLP1 and VDLP2 algorithms. The characteristics of user mobility are considered and a free-flowing vehicular traffic is assumed. Simulation results show that the use of vehicular mobility information in the distributed dynamic channel algorithms with violation to the reuse pattern, produce a considerable increase in the system capacity at the expense of an insignificant degradation of the quality of service. For a grade of service (GOS) of 0.1, the VDLP1 and VDLP2 carry 4% and 1.5% more traffic than the maximum packing algorithm, respectively. For the same GOS, the VDLP1 and VDLP2 carry 68% and 64% more traffic than the fixed channel assignment algorithm, respectively.

In this paper the application of a linear-quadratic processor is proposed for detection of each user's signal in a direct sequence code division multiple access scheme and, in particular, for W-CDMA systems. In this method, the knowledge of the user of interest, and some statistical knowledge of interfering transmitters' signals are used to detect the desired user's signal without needing exact "a priori" knowledge of the interfering signal parameters such as spreading sequences and signal powers. Parameters of the proposed processor, which are derived so as to maximise the signal-to-interference-plus-noise ratio (SINR), can generally be obtained by solving a system of linear equations for which many effective techniques exist. A model for this detection procedure is developed and shown--through analytical and numerical results--to offer a good compromise between complexity and quality of performance.

In this article, an efficient vector quantization (VQ) scheme called side-match finite-state vector quantization with adaptive block classification is presented for image compression. It makes use of edge information contained in image in additional to the average values of blocks forming the image. In order to achieve low bit rate coding while preserving good quality images, neighboring blocks are utilized to predict the class of current block. Image blocks are mainly classified as edge blocks and non-edge blocks in this coding scheme. To improve the coding efficiency, edge blocks and non-edge blocks are further reclassified into different classes, respectively. Moreover, the number of bits for encoding an image is greatly reduced by foretelling the class of input block and applying small state codebook in corresponding class. The improvement of the proposed coding scheme is attractive as compared with other VQ techniques.

In this paper, performance of a PN code acquisition scheme is analyzed and simulated for a DS/CDMA overlay system where a CDMA user and a narrowband user coexist in the same frequency band. A narrowband user is modelled as a narrowband interference (NBI) located at the fraction of a CDMA user's bandwidth. To suppress the NBI, an interference suppression filter is employed at the receiver frontend. Acquisition performance is evaluated in terms of mean acquisition time using state transition diagram for acquisition process. To apply for a DS/CDMA mobile cellular environments, multiple access interference and imperfection of power control are taken into account in the analysis of acquisition performance. The imperfect power control is considered by modelling the power of each user to be lognormally distributed about nominal received power. From the simulation results, it is shown that for the cases of perfect and imperfect power control, the interference suppression filter is very effective for supprssion of the NBI and rapid PN code acquisition in a DS/CDMA overlay environment. It is also shown that the one-sided tap number of 5 for interference suppression filter is sufficient to suppress the NBI. And, capacity estimates are compared based on acquisition and BER performance. The analysis in this paper can be applied to the practical situations for a DS/CDMA overlay environment.