We propose a software architecture for one-stop services of electronic commerce (EC). Users currently have trouble using multiple EC services because they are provided independently. Therefore a mediator that combines EC services and provides one-stop services to users would be useful. Service matching and service collaboration are important issues in the mediator because they are the main difficulties for users. The proposed architecture provides solutions to these issues. Multiple service assignment provides suitable combinations of EC services, flow division enables efficient execution of the combined EC services, and dynamic alternative service assignment enables flexible failure avoidance during the execution of combined services. These features make the proposed architecture a suitable mediator for EC services.

This paper describes agent technology and the various ways in which it can be applied to command, control, communications and intelligence in general, and to network-centric warfare in particular. The paper provides a brief overview of agents, their properties, and their advantages. It covers the concept of the current military trend, network-centric warfare. Problems associated with agents are described, including the conflict between security and autonomy, in a distributed environment. The paper concludes with a discussion of research trends in mobile agents, particularly with regard to applications in the Department of Defense.

This paper proposes a bandwidth division type parallel combinatory (PC) spread spectrum (SS) modulation scheme. In the proposed system, a given system bandwidth for the conventional single-carrier PC-SS system is divided into H subbands, and H PC-SS signals are transmitted in parallel. We evaluate the frame error rate (FER) of the proposed system under the asynchronous CDMA environment. We show that the proposed scheme provides a smaller FER than the single-carrier PC-SS system for a given information bit rate. We also show that the proposed scheme attains a higher information bit rate than the single-carrier PC-SS system for a given FER.

Single-hop communication methods of the current wireless network cannot meet new demands in new domains, especially ITS (Intelligent Transport Systems). Even though the ad-hoc network architecture is expected to solve this problem, but the nature of a dynamic topology makes this routing hard to be realized. This paper introduces a new ad-hoc routing algorithm, which is inspired by [1]. In their system, some control agents explore the network and update routing tables on their own knowledge. Using these routing tables, other agents deliver messages. They considered the feasibility of the agent-based routing system, but did not refer to an efficient algorithm. In this paper, we consider that algorithm without increasing network load. We propose multiple entries for each destination in the routing table to store much more information from agents and evaluating them to make better use of information, which succeeded in raising the network connectivity by about 40% by simulation.

Sector antennas provide many advantages such as when combined with a narrow beam antenna, they become particularly effective in achieving high-speed wireless communication systems and they aid in simplifying the structure. These antennas have a drawback in that as the number of sectors increases, the antenna size rapidly increases. Therefore, downsizing the sector antenna has become a major research topic. A promising candidate is utilizing a phased-array type antenna; however, this antenna requires a phase-shifter circuit for beam scanning and generally the feeding circuit for this type of antenna is very complicated. To address these issues, we propose a self-selecting feeding circuit that is controlled by the same control circuit and is operated similarly to the conventional single port n-th throw (SPNT) switch. We fabricated a small cylindrical 12-sector antenna at 19 GHz employing the proposed feeding circuit for verification purposes. Furthermore, this paper clarifies the design method of this feeding circuit where the antenna diameter is 71 mm, and the results clearly show that the gain is more than 12 dBi.

We have experimentally measured the propagation characteristics of 60-GHz-band millimeter wave between two vehicles to design of inter-vehicle communication (IVC) system in intelligent transport systems (ITS). Received power and bit error rates of 1-Mbps data transmission between a transmitter mounted on a leading vehicle and two receivers attached on a following vehicle were measured. A two-ray propagation model was devised to calculate the instantaneous propagation characteristics, and these estimations agree well with the measured characteristics. The feasibility of 1-Mbps data transmission between the running vehicles on an actual expressway was demonstrated. The cumulative distribution of received power between the two running vehicles when their height from the road surface fluctuated was also determined from the proposed two-ray propagation model and experimental measurements.

Several subband array methods have been proposed as useful means to perform joint spatio-temporal equalization in digital mobile communications. These methods can be applied to mitigate problems caused by the inter-symbol interference (ISI) and co-channel interference (CCI). The subband array methods proposed so far can be classified into two major schemes: (1) a centralized feedback scheme and (2) a localized feedback scheme. In this paper, we propose subband arrays with partial feedback scheme, which generalize the above two feedback schemes. The main contribution of this paper is to derive the steady-state mean square error (MSE) performance of subband arrays implementing these three different feedback schemes. Unlike the centralized feedback scheme which can be designed to provide the optimum equalization performance, the subband arrays with localized and partial feedback schemes are in general suboptimal. The performance of these two suboptimal feedback schemes depends on the channel characteristics, the filter banks employed, and the number of subbands.

The field of mobile communications has continued to spread with astonishing speed in recent years. The expansion of mobile communications and the Internet has not only brought changes to communications services but also exerted huge effects on the economy and daily life. IMT-2000, International Mobile Telecommunications, is the next generation system for mobile communications systems currently being implemented. Standardization and development of IMT-2000 are in much progress under international frameworks to start commercial service by around the year 2001. This paper focuses in particular on radio transmission technology, giving an overall view of IMT-2000 standardization and technological status, as well as future technical directions extending beyond IMT-2000.

As Information Technology progresses, our daily lives are getting "connected" more and more. At the same time, however, problems are appearing. The center of these problems can be captured as the "Communication Overflow. " To cope with such problems, we propose an approach that tries to provide a communication environment that assists users in managing their communication activities. The key notion of this approach is to enhance the "Awareness of Connectedness. " Here, agents which are suggestive of awareness of connectedness play an important role. In this paper, we describe the key notion and introduce a brief road-map towards the environment for the awareness of connectedness. Two candidate tools for the environment are described. The first one is a visualization tool for communication media that provides feedback of users' communication activities. Its purpose is to enhance the awareness for communication. The second tool is a simple, intuitive interactive media that exchanges the statuses of users. It is an alternative network communication media that might be suitable for very light-weight, almost-acknowledge-only communication mode. Some results on an experiment of these two tools are also reported.

CRL (Communications Research Laboratory, Independent Administrative Institution Japan) is developing a road to vehicle multiple-service communication system based on RoF (Radio over Fiber) technology in a millimeter-wave frequency region of 36-37 GHz. In the experimental system, vehicle can receive three wireless services such as PHS (Personal Handy-phone System), ETC (Electronic Toll Collection system), SB (Satellite Broadcasting). In this paper, the system concept and experimental system configuration are introduced. Furthermore, SDR (Software Defined Radio) mobile terminal technology is mentioned and a new concept for a next generation mobile communication network system based on RoF is proposed.

In mechanical splice technology, loss change during temperature cycling is mainly caused by fiber slippage or shift at the interface between fibers and fiber clamping substrates. The upper limit of the fabrication accuracy of the fibers and substrates restricts the total number of fibers in a splice. To overcome this, we propose a novel fiber clamping method using the elasticity of the substrate surface. We clamp the fibers more strongly at the fiber clamping ends, where the fibers need a greater friction force than around the butt-joint, to hold them in position. Taking the case of an 8-fiber ribbon splice, we compared linear marks on the substrates with the boundary linewidth curves for the onset of slippage. We achieved an insertion loss change of less than 0.1 dB during a temperature cycling test in accordance with Telcordia Technologies test specification. When we clamp fibers using the plasticity of the substrate surface, we can also reduce the required fabrication accuracy. However, insufficient accuracy causes an unexpected loss change due to fiber shift as a result of a plastic flow on the substrate surface in contact with the fibers.

In this paper, a novel adaptive digital watermarking approach based upon human visual system model and fuzzy clustering technique is proposed. The human visual system model is utilized to guarantee that the watermarked image is imperceptible. The fuzzy clustering approach has been employed to obtain the different strength of watermark by the local characters of image. In our experiments, this scheme allows us to provide a more robust and transparent watermark.

This letter introduces an alternative adaptive beamforming with the total computational load of about O(3N) where N denotes the number of antenna elements. The proposed technique finds a weight vector that maximizes the received signal power at the array output by searching for the suboptimal phase of each weight in a multipath fading CDMA mobile communication environment.

The ultrasonic wave is widely used for acquiring perceptual information necessary for indoor/outdoor navigation of mobile robots, where the system is implemented as a sound navigation and ranging system (sonar). A robot equipped with multiple ultrasonic sonars is likely to exhibit undesirable operation due to erroneous measurements resulting from cross-talk among the sonars. Each sonar transmits and receives a pulse-modulated ultrasonic wave for measuring the range and identifying its own signal. We propose a technique for generating pulse patterns for multiple concurrently operated ultrasonic sonars. The approach considers pulse-pattern generation as a combinatorial optimization problem which can be solved by a genetic algorithm (GA). The aim is to acquire a pulse pattern satisfying certain conditions in order to avoid cross-talk or keep the probability of erroneous measurement caused by cross-talk low. We provide a method of genotype coding for the generation of the pulse pattern. Furthermore, in order to avoid a futile search encountered when the conventional technique is used, we propose an improved genotype coding technique that yields considerably different results from those of the conventional technique.

Smart cards and biometrics can be effectively combined for personal authentication over an open network. The combination is achieved as two-step authentication in which the smart card is authenticated based on a public key infrastructure, and the card holder is authenticated using the template stored in the smart card based on the biometric data. The biometric verification has to be executed in the card for security purposes. This paper describes a fingerprint verification method based on a popular biometric verification technique that can be embedded in a smart card. The prototype system that uses this verification method can verify fingerprints in a few seconds by using the data stored on the smart card.

Personal identity verification has a great variety of applications including access to computer terminals, buildings, credit card verification as well as EC. Algorithms for personal identity verification can be roughly classified into four categories depending on static/dynamic and biometric/physical or knowledge based. Finger prints, iris, retina, DNA, face, blood vessels, for instance, are static and biometric. Algorithms which are biometric and dynamic include lip movements, body movements and on-line signatures. Schemes which use passwords are static and knowledge based, whereas methods using magnetic cards and IC cards are physical. Each scheme naturally has its own advantages and disadvantages. A new algorithm is proposed for pen-input on-line signature verification incorporating pen-position, pen-pressure and pen-inclinations trajectories. A preliminary experiment is performed on a data base consisting of 293 genuine writings and 540 forgery writings, from 8 individuals. Average correct verification rate was 97.6% whereas average forgery refection rate was 98.7%. Since no fine tuning was done, this preliminary result looks very promising.

This letter shows the results of a series of link level simulations conducted to evaluate the performances of spatial and temporal equalizers (S/T-equalizers) using field measurement data. The configuration of the spatial and temporal equalizer discussed in this letter can be expressed as a cascade of an adaptive array antenna and maximum likelihood sequence estimator (MLSE): each of the adaptive array antenna elements has a fractionally spaced tapped delay line (FTDL), and the MLSE has taps covering a portion of channel delay profile. Bit error rate (BER) performances of the S/T-equalizers are presented, and performance sensitivity to symbol timing offset is investigated.

In wideband direct sequence code division multiple access (W-CDMA), employing an adaptive antenna array is a very promising technique to reduce severe multiple access interference (MAI) especially from high rate users. This paper proposes a fast and accurate two-step beam tracking algorithm implemented in a pilot symbol-assisted coherent adaptive antenna array diversity (CAAAD) receiver and evaluates its performance both by computer simulation and laboratory experiments. In the proposed scheme, the receiver antenna weights are updated by using both the signal-to-interference power ratio (SIR) measurements employing multiple sets of antenna weights (MSAW) and an adaptive algorithm based on the minimum mean square error (MMSE) criterion, in which other sets except for a original set of antenna weights are simply generated by a original set. Computer simulation results show that antenna weights of a four-antenna CAAAD receiver using the proposed beam tracking algorithm tracks changes in the direction of arrival (DOA) of the desired user at up to 34.3 degrees/sec, which corresponds to 215 km/h at 100 m from a base station. We also confirm based on the experiments in a radio anechoic room that the generated antenna weights track the DOA changes up to 12.3 degrees/sec.

The number of studies on adaptive antennas has greately increased in resent years in Japan. Most of these studies have sought to enhance the capacity and suppress multipath signals in wireless mobile communications. Adaptive antennas are expected to play an important role in future mobile radio systems. In this paper, we review the history and trends of adaptive antenna studies in Japan. We describe typical adaptive processing algorithms and contributions by Japanese researchers. We then introduce some applications of adaptive antennas for mobile communications. Furthermore, we discuss multi-dimensional signal processing, which is an extended version of the adaptive antenna.

This paper describes a biometric-based key generation method and its application to a secure communication system. In the proposed method, a personal key which is unique to each user is generated by extracting his/her biometric information. Using the generated personal key, a secure communication system which has the functions of confidentiality and user authentication is realized. As an example of the proposed method, we introduce a personal key generation method based on one's handwriting, and a secure telewriting system which enables the encryption of handwriting information as well as the authentication of a writer. Some simulation results indicate the possibility of realizing the above functions by using a writer's personal key.