Visualizing occluded objects is a useful applications of Mixed Reality (MR), which we call "see-through vision." For this application, it is important to display occluded objects in such a manner that they can be recognized intuitively by the user. Here, we evaluated four visualization methods for see-through vision that can aid the user to recognize occluded objects in outdoor scenes intuitively: "elimination of occluding objects," "ground grid," "overlaying model of occluding object," and "top-down view." As we used a new handheld MR device for outdoor see-through vision, we performed subjective experiments to determine the best combination of methods. The experimental results indicated that a combination of showing the ground grid, overlaying wireframe models of occluding objects, and top-down view to be optimal, while it was not necessary to display occluding objects for outdoor see-through vision with a handheld device, because users can see them with the naked eye.

A communication support interface controlled by eye movements and voluntary eye blink has been developed for disabled individuals with motor paralysis who cannot speak. Horizontal and vertical electro-oculograms were measured using two surface electrodes attached above and beside the dominant eye and referring to an earlobe electrode and amplified with AC-coupling in order to reduce the unnecessary drift. Four directional cursor movements --up, down, right, and left-- and one selected operation were realized by logically combining the two detected channel signals based on threshold settings specific to the individual. Letter input experiments were conducted on a virtual screen keyboard. The method's usability was enhanced by minimizing the number of electrodes and applying training to both the subject and the device. As a result, an accuracy of 90.1 3.6% and a processing speed of 7.7 1.9 letters/min. were obtained using our method.

We report a specially designed encoding technique for sign language video sequences supposing that the technique is for sign telecommunication such as that using mobile videophones with a low bitrate. The technique is composed of three methods: gradient coding, precedence macroblock coding, and not-coded coding. These methods are based on the idea to distribute a certain number of bits for each macroblock according to the evaluation of importance of parts of the picture. They were implemented on a computer and encoded data of a short clip of sign language dialogue was evaluated by deaf subjects. As a result, the efficiency of the technique was confirmed.

Our investigation is presented into analysis of the co-channel interference (CCI) statistic in orthogonal frequency-division multiple access (OFDMA) uplink systems. The derived statistic is then used to analyze the performance of reuse partitioning (RP)-based dynamic channel allocation (DCA). Analysis and simulation results show that the performance of DCA in multi-cell environments is noticeably dependent on the CCI. Finally, the results of the analysis yield the optimum RP area for achieving the maximum spectral efficiency.

This paper discusses the design and performance of on-chip passive components of transmission lines (TR) and inductors. First, the measurement technique of on chip passives is discussed. A transmission line that can be used for Gbps signal propagation on Si CMOS is examined. As a high density transmission line structure of diagonal-pair differential TR line is described. Also, a circuit and TR line is introduced for above 10 Gbps signal propagation. The on-chip inductor which is a key passive component in RF application of Si CMOS technology is discussed. We examine some on-chip inductors that have been developed in our group: small area inductor, high performance inductor using WL-CSP (Wafer-Level Chip-Size-Packaging) technology. Finally, a wide tuning range LC-VCO using a variable inductor for RF reconfigurable circuit is introduced.

The path coloring problem is to assign the minimum number of colors to a given set P of directed paths on a given symmetric digraph D so that no two paths sharing an arc have the same color. The problem has applications to efficient assignment of wavelengths to communications on WDM optical networks. In this paper, we show that the path coloring problem is NP-hard even if the underlying graph of D is restricted to a binary caterpillar. Moreover, we give a polynomial time algorithm which constructs, given a binary caterpillar G and a set P of directed paths on the symmetric digraph associated with G, a path coloring of P with at most colors, where L is the maximum number of paths sharing an edge. Furthermore, we show that no local greedy path coloring algorithm on caterpillars in general uses less than colors.

Assistive technology (AT) is becoming increasingly important for improving the mobility and language learning capabilities of persons with disabilities, thus enabling them to function independently and to improve their social opportunities. The Morse code has been shown to be a valuable tool in assistive technology, augmentative and alternative communication, and rehabilitation for people with neuromuscular diseases such as amyotrophic lateral sclerosis, multiple sclerosis, and muscular dystrophy. In this paper, we designed and implemented a wireless environmental control aid system using the Morse code as an adapted access communication tool, which includes three types of switch: single-switch, double-switch, and six-switch types. People with disabilities can easily control all types of electronic appliance without restrictions owing to spatial arrangements using a signal transmission based on radio frequency (RF). Experimental results revealed that three participants with disabilities were able to gain access to electronic facilities after six weeks of practice with the new system.

In this paper, we propose the construction of a web-based Question Answering (QA) system for restricted domain, which combines three resource information databases for the retrieval mechanism, including a Question&Answer database, a special domain documents database and the web resource retrieved by Google search engine. We describe a new retrieval technique of integrating a probabilistic technique based on OkapiBM25 and a semantic analysis which based on the ontology of HowNet knowledge base and a special domain HowNet created for the restricted domain. Furthermore, we provide a method of question expansion by computing word semantic similarity. The system is first developed for a middle-size domain of sightseeing information. The experiments proved the efficiency of our method for restricted domain and it is feasible to transfer to other domains expediently using the proposed method.

Analog-to-Digital converters (ADCs) for video applications have made exciting progress in miniaturization and power reduction in the past 20 years. This paper mainly describes the key technologies for miniaturization and power reduction of 10-bit video-frequency ADCs. By reviewing useful architectures and circuit schemes for video-frequency ADCs, self-calibration techniques and interleaving techniques are surveyed. The subranging pipeline look-ahead ADC architecture is introduced. It has a potential for reducing power consumption and improving conversion rate when minute deep submicron CMOS devices are used with low supply voltage.

A compact on-chip signal monitor circuit uses voltage mode sensing by a source follower circuit with small input device geometry, followed by a current-mode sample and a hold circuit that is connected to a shared current output bus. A prototype signal monitor circuit demonstrated a 1.1-GHz effective bandwidth for 1.0-V full-swing digital signals in a 90-nm CMOS technology, where the monitor used 2.5-V I/O CMOS transistors and occupied a 30 µm120 µm silicon area. We also showed that such signal monitor circuits can be tailored to sense of power-supply, ground, as well as full-swing logic signal wirings, and form an array with a single current output. Therefore, an on-chip multi-channel signal monitor enables multiple-points as well as multiple-voltage domain waveform acquisition for the purpose of the in-depth study of digital signal integrity.

Recent work has shown that the usage of multiple antennas at the transmitter and receiver in a flat fading environment results in a linear increase in channel capacity. But increasing the number of antennas induces the higher hardware costs and computational burden. To overcome those problems, it is effective to select antennas appropriately among all available ones. In this paper, a new antenna selection method is proposed. The transmit antennas are selected so as to maximize the channel capacity using the genetic algorithm (GA) which is the one of the general random search algorithm. The results show that the proposed GA achieves almost the same performance as the optimal selection method with less computational amount.

A new simply implemented collusion-attack free identity-based non-interactive key sharing scheme (ID-NIKS) has been proposed. A common-key can be shared by executing only once a modular exponentiation which is equivalent to RSA deciphering, and the security depends on the difficulty of factoring and the discrete logarithm problem. Each user's secret information can be generated by solving two simple discrete logarithm problems and synthsizing their solutions by linear combination. The detail comparison with the Maurer-Yacobi's scheme including its modified versions shows that the computational complexity to generate each user's secret information is much smaller and the freedom to select system parameters is much greater than that of the Maurer-Yacobi's scheme. Then our proposed scheme can be implemented very easily and hence it is suitable for practical use.

Recently, Yoon et al. exhibited the vulnerability of the smart-card-equipped password based authentication protocol proposed by Chien et al. to the Denning-Sacco attack. Furthermore, they also pointed out that the protocol does not provide the perfect forward secrecy. Accordingly, they presented an enhanced protocol to strengthen the security. This letter, however, demonstrates an interleaving attack on the Yoon et al.'s improved protocol and also discusses how to defend the protocol from the attack presented here.

A hardware algorithm for computing the reciprocal of the Euclidean norm of a 3-dimensional (3-D) vector which appears frequently in 3-D computer graphics is proposed. It is based on a digit-recurrence algorithm for computing the Euclidean norm and an on-line division (on-line reciprocal computation) algorithm. These algorithms are modified, so that the reciprocal of the Euclidean norm is computed by performing on-line division where the divisor is the partial result of Euclidean norm computation. Division, square-rooting, and reciprocal square-root computation, which are important operations in 3-D graphics, can also be performed using a circuit based on the proposed algorithm.

A reduced-sample-rate (RSR) sigma-delta-pipeline (SDP) analog-to-digital converter architecture suitable for high-resolution and high-speed applications with low oversampling ratios (OSR) is presented. The proposed architecture employs a class of high-order noise transfer function (NTF) with a novel pole-zero locations. A design methodology is developed to reach the optimum NTF. The optimum NTF determines the location of the non-zero poles improving the stability of the loop and implementing the reduced-sample-rate structure, simultaneously. Unity gain signal transfer function to mitigate the analog circuit imperfections, simplified analog implementation with reduced number of operational transconductance amplifiers (OTAs), and novel, aggressive yet stable NTF with high out of band gain to achieve larger peak signal-to-noise ratio (SNR) are the main features of the proposed NTF and ADC architecture. To verify the usefulness of the proposed architecture, NTF, and design methodology, two different cases are investigated. Simulation results show that with a 4th-order modulator, designed making use of the proposed approach, the maximum SNDR of 115 dB and 124.1 dB can be achieved with only OSR of 8, and 16 respectively.

This paper proposes a multiple-input multiple-output (MIMO) eigenmode transmission technique which transmits different data streams on eigenmodes of different multi-path components while suppressing intra and inter-eigenmode interferences by means of a turbo equalization technique. This paper also evaluates the effectiveness of the proposed system in frequency selective fading conditions. Computer simulation results confirms the proposed technique is effective even in high spatial correlation cases.

In this paper, a new dimming algorithm for the electronic ballast of an electrodeless fluorescent lamp is proposed. The proposed method is based on the burst dimming method that controls the duty ratio for the two switches of the electronic ballast by intermittently modulated pulse signal. This paper presents a fully digital circuit using an erasable programmable logic device (EPLD). To verify the validity of the proposed method, the implemented control circuit was applied to the electronic ballast for a 100 W electrodeless fluorescent lamp. As a result, a dimming method with a wide illumination range from 5 to 100% was obtained.

In this paper, we present a polling scheme which allows for augmenting the support of voice communications in point co-ordination function (PCF) of IEEE 802.11 wireless networks. In this scheme, the Access Point (AP) of the Basic Service Set (BSS) maintains two polling lists, i.e. the talking list and the silence list. Based on the talking status of the stations identified via silence detection, two lists are dynamically adjusted by the AP. Temporary removal is applied to the stations in the silence list to further upgrade the performance. The conducted study based on simulation has shown that the proposed scheme can support more voice stations and has a lower packet loss rate than that obtained by four reference polling algorithms.

This paper deals with the performance evaluation of two types of dynamic change, called Flush and SCO (Synthetic Cut-Over), for state machine WF-nets. As an evaluation measure of dynamic change for marked graph WF-nets, change time has been used. We first generalize change time so as to apply it to dynamic change for state machine WF-nets. By using its maximum value, we evaluate the worst-case of dynamic change for state machine WF-nets. We call the maximum value as worst change time. Then under the same assumptions as our previous studies, we give methods of calculating worst change time of Flush and SCO dynamic changes. We also clarify the relation on worst change time between them. Finally we evaluate them by comparing the values of worst change time for an actual example of dynamic change.

Feedback-type Adaptive Array Antenna has been proposed for frequency division duplexed (FDD) system, where the mobile station (MS) measures channel characteristics and sends those back to the base station (BS). Using a higher number of feed-back bits provides better performance. However it wastes channel capacity of the up-link. On the other hand, error in feedback signals transmission causes significant performance degradation. To solve these problems, this paper proposes a method that the MS sends back the difference between the optimum weights calculated at the MS and weights which are currently used at the BS. Bit error rate performance of the system is shown under a realistic propagation condition.