This paper deals with the method for generation of maximal-period sequences which are designed by properly quantizing the variable state of a class of one-dimensional piecewise-linear onto maps. We confirmed that the proposed method enables us to generate many maximal-period sequences from such maps including De-Bruijn cases.

In provisioning packet data service on wireless cellular networks, a scheme of altering connection status between mobile and base stations appeared intending to efficiently utilize resource during idle periods. In such a scheme, connection components are sequentially released as an idle period persists, while the transmitting station converts to an transmission activity mode as the station is loaded with packets. However, actual resume of transmission activity is postponed by connection retrieval time to restore lost connection components. In general, an idle period affects the following connection retrieval time, which in turn produces an impact on the forthcoming idle period. Such chain reaction also makes a significant influence on overall packet delay performance. In this paper, as a way of improving packet delay performance, we propose two schemes identified as conservative extension and load threshold schemes. In the conservative extension scheme, we intentionally extend connection retrieval times so that each connection retrieval time is guaranteed not to be lower than a certain value. On the other hand, according to the load threshold scheme, a retrieval of lost connection components is postponed until packets are accumulated at the transmitting station up to a prescribed threshold. An increase in the value and threshold incurs an additional stand-by before resuming transmission activity in both proposed schemes. In turn, such intentional stand-by may contribute to regulating the length of idle period and connection retrieval time, and subsequently improving packet delay performance. To inspect the impact of conservative extension and load threshold schemes on packet delay performance, we first investigate the properties of idle periods. Secondly, for Poisson packet arrivals, we present an analytical method to exactly calculate the moments of packet delay time (at steady state) in each scheme. From numerical examples, we confirm the existence of non-trivial optimal value and threshold minimizing average packet delay or packet delay variation and conclude that conservative extension and load threshold schemes are able to enhance packet delay performance in various environments.

This paper presents an efficient LSP quantizer implementation for low bit-rate coders. The major feature of the quantizer is that it uses a truncated cepstral distance criterion for the code selection procedure. This approach has generally been considered too computationally costly. We utilized the quantizer with a moving-average predictor, two-stage-split vector quantizer and delayed decision. We have investigated the optimal parameter settings in this case and incorporated the quantizer thus obtained into an ITU-T 4-kbit/s speech coding candidate algorithm with a bit budget of 21 bits. The objective performance is better than that with a conventional weighted mean-square criterion, while the complexity is still kept to a reasonable level. The paper also describes the codebook design and techniques that were employed to achieve robustness in noisy channel conditions.

In this article we analyze the performance of a space division output buffered multichannel switch operating in an ATM multimedia environment as follows. Fixed size packets belonging to two classes arrive onto the switch inputs in each time slot. Class-1 packets, representing real time traffic such as live audio and live video communications, are sensitive to delay but insensitive to loss and have their own service time needs. Class-2 packets, representing nonreal time communications such as file transfers, are insensitive to delay but sensitive to loss and have their different service time needs. To respond to the class-1 delay sensitivity, the switch gives class-1 packets higher service priority over class-2. And to respond to the difference in service time needs, the switch operates at two service rates, one for each class. This latter assumption is the major feature of the article, as previous studies have usually assumed that the two classes have the same service needs and thus the same service rate. For the purpose of the analysis, the switch is modelled as a priority, discrete time, batch arrival, multiserver queueing system, with infinite buffer and two geometric service times with two parameters. Performance measures analyzed are system occupancy and packet waiting time.

This paper presents a methodology for optimizing the layout of on-chip spiral inductors using structural parameters and design frequency in a response surface method. The proposed method uses scattering parameters (S-parameter) to express inductor characteristics, and hence is independent of spiral geometries and equivalent circuit models. The procedure of inductor optimization is described, and a design example is presented.

In this paper, the effects of visual information on associated auditory information were investigated when presented simultaneously under dynamic conditions on a wide screen. Experiments of an auditory-visual stimulus presentation using a computer graphics movie of a moving patrol car and its siren sound, which were combined in various locations, were performed in 19 subjects. The experimental results showed the following: the visual stimulus at the beginning of the presentation captured the sound image stronger than that at the end (i.e., beginning effect), the sound image separated from the visual image even when both stimulus locations were exactly at the same place and then when both stimuli moved in opposite directions from each other, the visual stimulus tended to capture the sound image stronger in the peripheral visual field than in the central visual field, and the visual stimulus moving toward the sound source captured the sound image stronger than that moving away from the sound source.

Design approach to improving fmax of InP-based HBTs by combining lateral scaling (lithographic scaling) and vertical scaling (improving fT) is discussed. An HBT scaling model is formulated to provide means of analyzing the essential impact of scaling on fmax. The model was compared with measurements of single and double heterojunction bipolar transistors with different fT and various emitter sizes. While a high fmax of 313 GHz was achieved using submicron HBT with high fT, it was found that further improvement could have been obtained by reducing the emitter resistance, which has imposed considerable limit on lateral scaling.

This paper investigates the relations between IP network performances and the speech quality of the Voice over IP (VoIP) service through extensive experiments on a test bed network. The aim is to establish an effective and practical methodology for telecommunications operators to manage the quality of VoIP service via the management of IP network performances under their control. As IP network performances, utilization of the bottleneck link in the test bed and the following statistical factors of VoIP packets are examined: the standard deviation of delay variations (jitters), the standard deviation of packet interarrival times, and the packet loss ratio. On the other hand, VoIP speech quality is monitored as the Perceptual Evaluation of Speech Quality (PESQ). To investigate the relations under various network conditions, the experiments are performed by varying the following network related parameters of the test bed: the bandwidth of the bottleneck link, the size of the bottleneck buffer, the propagation delay, and the average of the data sizes transmitted as background data traffic. Statistical analyses of the experimental results suggest that managing the standard deviation of jitters in a network serves as a promising methodology, because its close relation to VoIP speech quality possesses robustness to changes in the network conditions. The robustness makes it practically useful since telecommunications operators can apply it to their networks, which are subject to change. The findings in this paper have opened up new visions for telecommunications operators to manage the Quality of Service (QoS) of VoIP service.

In this paper, we propose a method of linear time-varying filtering of discrete time signals. The objective of this method is to derive a component, of an input signal, whose alias-free generalized discrete time-frequency distribution [Jeong & Williams 1992] concentrates on a specific region of a time-frequency plane. The method is essentially realized by computing an orthogonal projection of an input onto a subspace that is spanned by orthonormal signals, whose distributions concentrate on the region. We show that such orthonormal signals can be derived as eigenvectors of a matrix whose components are explicitly expressed by using the kernel of the distribution and the regions. This result shows that we can design such a filter prior to processing of the input if the specific region is given as a priori. This result is a generalization of [Hlawatsch & Kozek 1994], that is originally derived for the continuous Wigner distributions, to the discrete distributions.

In their paper, G. Gong and S.Q. Jiang construct a new pseudo-random sequence generator by using two ternary linear feedback shift registers (LFSR). The new generator is called an editing generator which a combined model of the clock-controlled generator and the shrinking generator. For a special case (Both the base sequence and the control sequence are mm-sequence of degree n), the period, linear complexity, symbol distribution and security analysis are discussed in the same article. In this paper, we expand the randomness results of the edited sequence for general cases, we do not restrict the base sequence and the control sequence has the same length. For four special cases of this generator, the randomness of the edited sequence is discussed in detail. It is shown that for all four cases the editing generator has good properties, such as large periods, high linear complexities, large ratio of linear complexity per symbol, and small un-bias of occurrences of symbol. All these properties make it necessary to resist to the attack from the application of Berlekamp-Massey algorithm.

Modern video compression usually consists of ME/MC (Motion Estimation/Motion Compensation), transform, and quantization of the transform coefficients. Efficient bit allocation technique to distribute available bits to motion parameters and quantized coefficients is an important part of the whole system. A method that is very complex and/or needs buffering of many future frames is not suitable for real time application. We develop an efficient bit allocation technique that utilizes the estimated effect of allocated bits to motion parameter and quantization on the overall quality. We also propose an hierarchical block based ME/MC technique that requires less computations than classical BMA (Block Matching Algorithm) while offering better motion estimation.

This paper describes a 2.4-GHz downconverter that runs on a 1-V supply. The downconverter integrates an LNA, a quadrature mixer, a complex channel-select band-pass filter (BPF), a limiting amplifier, and a frequency doubler using 0.2-µm CMOS/SOI technology. The frequency doubler doubles the frequency deviation of FM signals as well as the frequency itself, which in turn doubles the modulation index. This improves the sensitivity of FM demodulation. The power consumption of the downconverter is 23 mW with a 1-V power supply. A bit-error-rate (BER) measurement using the downconverter and a demodulation IC shows -76.5-dBm sensitivity at a 0.1% BER.

Integral equation method is used to compute three-dimension-structure capacitance in this paper. Since some multi-conductor structures present regular periodic property, the periodic cell is used to reduce the computational domain with adding appropriate magnetic and electric walls. The periodic Green's function in the integral equation method is represented in the form of infinite series with slow convergence. In this paper, Shanks transformation is used to accelerate the convergence. Numerical examples show that the proposed method is accurate with a much higher efficiency in capacitance extraction for 3-D periodic structures.

This study was conducted to examine the relationship between technostress - techno-centered tendency- and antisocial behavior on computers. Questionnaire data of computer operators were analyzed by multivariate-analysis. The results of the analysis indicated that high techno-centered tendency has a strong relationship with antisocial behavior on computers. Among the component factors of techno-centered tendency, absorption in operating computers was proven to have the strongest association with antisocial behavior on computers.

A data stream is a massive unbounded sequence of data elements continuously generated at a rapid rate. Consequently, the knowledge embedded in a data stream is likely to be changed as time goes by. However, most of mining algorithms or frequency approximation algorithms for a data stream are not able to extract the recent change of information in a data stream adaptively. This is because the obsolete information of old transactions which may be no longer useful or possibly invalid at present is regarded as important as that of recent transactions. This paper proposes an information decay method for finding recent frequent itemsets in a data stream. The effect of old transactions on the mining result of a data steam is gradually diminished as time goes by. Furthermore, the decay rate of information can be flexibly adjusted, which enables a user to define the desired life-time of the information of a transaction in a data stream.

This paper proposed a watermarking algorithm for image, which assumed an image compression based on DWT (Discrete Wavelet Transform). To reduce the amount of computation, this algorithm selects the watermarking positions by a threshold table which is statistically established from computing the energy correlation of the corresponding wavelet coefficients. The proposed algorithm can operate in a real-time if the image compression process operates in a real-time because the watermarking process was designed to operate in parallel with the compression process. Also it improves the property of losing the watermak and reducing the compresson ratio by the quantization and Huffman coding steps. It was done by considering the sign of the coefficients and the change in the value for watermarking. Visually recognizable pattern such as a binary image were used as the watermark. The experimental results showed that the proposed algorithm satisfied the properties of robustness and imperceptibility that are the major conditions of watermarking.

Ship handling for leaving and entering port always carries out for a captain, deck officers and quartermasters and sometimes include a pilot. For navigational watch keeping at sea except for a narrow channel and under restricted visibility etc., the deck officer and quartermaster do it. They achieve safe and efficient navigational watch keeping with their teamwork at a ship's bridge. The importance of teamwork has been recognized in the shipping world, and its training and education methods are also thought over. However, their evaluation is not clear, because they are depended on the experience of the trainers. Therefore, we need to make an evaluation method of teamwork for education and training of the ship handling. In this paper, we define that ship's bridge teamwork is shown by 1) a change of mental workload level and 2) a change of mental workload for time. We challenge to evaluate teammates' mental workload in the ship's bridge with R-R interval of subjects' heart rate variability, and we evaluate their mental workloads with the following three steps. 1) To confirm the evaluation of the mental workload of a ship's navigator with R-R interval. 2) To evaluate teamwork with R-R interval in case of an oral presentation at meetings as pre-experiments. 3) To evaluate the teammates' mental workload among ship's bridge team in case of a leaving port. Their results showed that the method using R-R interval was sufficient for the evaluation of teamwork effects.

This paper first discusses the misinterpretation of the concept of "ubiquitous computing" that Mark Weiser originally proposed in 1991. Weiser's main message was not the ubiquity of computers, but the transparency of interface that determines users' perception of digital technologies embedded in our physical environment seamlessly. To explore Weiser's philosophy of transparency in interfaces, this paper presents the design of an interface that uses glass bottles as "containers" and "controls" for digital information. The metaphor is a perfume bottle: Instead of scent, the bottles have been filled with music -- classical, jazz, and techno music. Opening each bottle releases the sound of a specific instrument accompanied by dynamic colored light. Physical manipulation of the bottles -- opening and closing -- is the primary mode of interaction for controlling their musical contents. The bottles illustrates Mark Weiser's vision of the transparent (or invisible) interface that weaves itself into the fabric of everyday life. The bottles also exploits the emotional aspects of glass bottles that are tangible and visual, and evoke the smell of perfume and the taste of exotic beverages. This paper describes the design goals of the bottle interface, the arrangement of musical content, the implementation of the wireless electromagnetic tag technology, and the feedback from users who have played with the system.

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.

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