Further development of a network based on the Inverse Function Delayed (ID) model which can recall temporal sequences of patterns, is proposed. Additional advantage is taken of the negative resistance region of the ID model and its hysteretic properties by widening the negative resistance region and letting the output of the ID neuron be almost instant. Calling this neuron limit ID neuron, a model with limit ID neurons connected pairwise with conventional neurons enlarges the storage capacity and increases it even further by using a weightmatrix that is calculated to guarantee the storage after transforming the sequence of patterns into a linear separation problem. The network's tolerance, or the model's ability to recall a sequence, starting in a pattern with initial distortion is also investigated and by choosing a suitable value for the output delay of the conventional neuron, the distortion is gradually reduced and finally vanishes.

To obtain a broad circular-coverage beam with low sidelobe, this paper proposes optimization design based on the quadratic programming approach for circular horns. The desired excitation coefficients of higher-order modes are pre-determined and also evaluated by calculating universal radiation patterns. We show a design example of a multimode horn which has circular-coverage beam with low sidelobe level of about -30 dB. The effectiveness of the designed horn is discussed by evaluating VSWR and radiation characteristics in X-band numerically and experimentally.

From lessons learned in medical data mining projects we show that integration of advanced computation techniques and human inspection is indispensable in medical data mining. We proposed an integrated approach that merges data mining and text mining methods plus visualization support for expert evaluation. We also appropriately developed temporal abstraction and text mining methods to exploit the collected data. Furthermore, our visual discovery system D2MS allowed to actively and effectively working with physicians. Significant findings in hepatitis study were obtained by the integrated approach.

The specification of a Multi-Agent System (MAS) involves the identification of a large number of entities and their relationships. This is a non-trivial task that requires managing different views of the system. Many problems concerning this issue originate in the presence of contradictory goals and tasks, inconsistencies, and unexpected behaviours. Such troublesome configurations should be detected and prevented during the development process in order to study alternative ways to cope with them. In this paper, we present methods and tools that support the management of contradictions during the analysis and design of MAS. Contradiction management in MAS has to consider both individual (i.e. agent) and social (i.e. organization) aspects, and their dynamics. Such issues have already been considered in social sciences, and more concretely in the Activity Theory, a social framework for the study of interactions in activity systems. Our approach applies knowledge from Activity Theory in MAS, especially its base of contradiction patterns. That requires a formalization of this social theory in order to be applicable in a software engineering context and its adaptation to agent-oriented methodologies. Then, it will be possible to check the occurrence of contradiction patterns in a MAS specification and provide solutions to those situations. This technique has been validated by implementing an assistant for the INGENIAS Development Kit and has been tested with several case studies. This paper shows part of one of these experiments for a web application.

A single-electron turnstile and electrometer circuit was fabricated on a silicon-on-insulator substrate. The turnstile, which is operated by opening and closing two metal-oxide-semiconductor field-effect transistors (MOSFETs) alternately, allows current quantization at 20 K due to single-electron transfer. Another MOSFET is placed at the drain side of the turnstile to form an electron storage island. Therefore, one-by-one electron entrance into the storage island from the turnstile can be detected as an abrupt change in the current of the electrometer, which is placed near the storage island and electrically coupled to it. The correspondence between the quantized current and the single-electron counting was confirmed.

A network based on the Inverse Function Delayed (ID) model which can recall a temporal sequence of patterns, is proposed. The classical problem that the network is forced to make long distance jumps due to strong attractors that have to be isolated from each other, is solved by the introduction of the ID neuron. The ID neuron has negative resistance in its dynamics which makes a gradual change from one attractor to another possible. It is then shown that a network structure consisting of paired conventional and ID neurons, perfectly can recall a sequence.

A general method for generating multiple two-dimensional frequency-hopping pilot signals with limited mutual interference, for propagation channel estimation in time and frequency with equidistant sampling, is presented. Each pilot signal uses a different generic frequency-hopping pilot pattern that is repeated in frequency domain, with repetition period equal to the desired sampling interval in frequency domain. Some interesting special cases of the general construction are considered as well. The practical applicability and usefulness of the proposed solution are demonstrated by the numerical evaluation of a set of frequency-hopping pilot patterns in a typical multi-cell scenario of the future evolved third generation cellular systems.

In this letter, we focus on rearranged pilot patterns for channel estimation in a mobile communication system using Orthogonal Frequency Division Multiplexing (OFDM). The conventional pilot patterns for channel estimation in OFDM systems do not have robust characteristics in time-varying channels. In order to overcome this weakness of the conventional pilot patterns, we propose the pilot patterns with robust mobility for OFDM systems, which can achieve a good error performance in time-varying multi-path fading channels. Simulation results show that the bit error rate (BER) performances of the proposed pilot patterns are better than those of the conventional pilot patterns in fast time-varying fading channels under the same pilot density and data rate.

The authors propose a system for searching the shape of human hands and fingers in real time and with high accuracy, without using any special peripheral equipment such as range sensor, PC cluster, etc., by a method of retrieving similar image quickly with high accuracy from a large volume of image database containing the complicated shapes and self-occlusions. In designing the system, we constructed a database in a way to be adaptable even to differences among individuals, and searched CG images of hand similar to unknown hand image, through extraction of characteristics using high-order local autocorrelational patterns, reduction of the amount of characteristics centering on principal component analysis, and prior rearrangement of data corresponding to the amount of characteristics. As a result of experiments, our system performed high-accuracy estimation of human hand shape where mean error was 7 degrees in finger joint angles, with the processing speed of 30 fps or over.

This paper aims at challenging Bernstein's problem called the "Degrees-of-Freedom problem," which remains unsolved from both the physiological and robotics viewpoints. More than a half century ago A.N. Bernstein observed that "dexterity" residing in human limb motion emerges from accumulated involvement of multi-joint movements in surplus DOF. It is also said in robotics that redundancy of DOFs in robot mechanisms may contribute to enhancement of dexterity and versatility. However, kinematic redundancy incurs a problem of ill-posedness of inverse kinematics from task-description space to joint space. In the history of robotics research such ill-posedness problem of inverse-kinematics has not yet been attacked directly but circumvented by introducing an artificial performance index and determining uniquely an inverse kinematics solution by minimizing it. Instead of it, this paper introduces two novel concepts named "stability on a manifold" and "transferability to a submanifold" in treating the case of human multi-joint movements of reaching and shows that a sensory feedback from task space to joint space together with a set of adequate dampings enables any solution to the overall closed-loop dynamics to converge naturally and coordinately to a lower-dimensional manifold describing a set of joint states fulfilling a given motion task. This means that, without considering any type of inverse kinematics, the reaching task can be accomplished by a sensory feedback with adequate choice of a stiffness parameter and damping coefficients. It is also shown that these novel concepts can cope with annoying characteristics called "variability" of redundant joint motions seen typically in human skilled reaching. Finally, it is pointed out that the proposed control signals can be generated in a feedforward manner in case of human limb movements by referring to mechano-chemical characteristics of activation of muscles. Based on this observation, generation of human skilled movements of reaching can be interpreted in terms of the proposed "Virtual-Spring" hypothesis instead of the traditional "Equilibrium-Point" hypothesis.

Fast and simple algorithm of a parity checker for a large residue numbers is presented. A new set of RNS moduli with 2r-(2l1) form for fast modular multiplication is proposed. The proposed RNS moduli has a large dynamic range for a large RNS number. The parity of a residue number can be checked by the Chinese remainder theorem (CRT). A CRT-based parity checker is simply organized by the Montgomery reduction method (MRM), implemented by using multipliers and the carry-save adder array. We present a fast parity checker with minimal hardware processed in three clock cycles for 32-bit RNS modulus set.

Model-based movement patterns play a crucial role in evaluating the performance of mobility-dependent Personal Communication Service (PCS) strategies. This study proposes a new normal walk model to represent more closely the daily movement patterns of a mobile station (MS) in PCS networks than a conventional random walk model. A drift angle θ in this model is applied to determine the relative direction in which an MS handoffs in the next one step, based on the concepts that most real trips follow the shortest path and the directions of daily motion are mostly symmetric. Hence, θ is assumed to approach the normal distribution with the parameters: µ is set to 0and σ is in the range of 5to 90. Varying σ thus redistributes the probabilities associated with θ to make the normal mobility patterns more realistic than the random ones. Experimental results verify that the proposed normal walk is correct and valid for modeling an n-layer mesh cluster of PCS networks. Moreover, when σ = 79.5, a normal walk can almost represent, and even replace, a random walk.

A multimode horn with both a low cross-polarization component less than -30 dB and good VSWR characteristics has been realized at frequency bands 8.6-9.8 GHz and 10.75-11.15 GHz. The improved performance of the proposed horn is verified by comparing with the previous dual-band double-flared horn. The design method for such a horn is based on the mode-matching approach combined with the optimization procedure. This paper proposes an objective function taking account of a spill-over loss and a rotational symmetry in the radiated field instead of an ideal radiation pattern. The effectiveness of our horn is verified by comparison between experimental results in the X band and predicted ones.

Interconnection networks play a crucial role in the performance of massively parallel computers. Hierarchical interconnection networks provide high performance at low cost by exploring the locality that exists in the communication patterns of massively parallel computers. A Hierarchical Torus Network (HTN) is a 2D-torus network of multiple basic modules, in which the basic modules are 3D-torus networks that are hierarchically interconnected for higher level networks. The static network performance of the HTN has already been studied and has been shown to be good. Dynamic communication performance has been evaluated under uniform traffic pattern but not under non-uniform traffic patterns. In this paper, we present a deadlock-free routing algorithm for the HTN using 3 virtual channels and evaluate the network's dynamic communication performance under three non-uniform traffic patterns, using the proposed routing algorithm. We evaluate the dynamic communication performance of HTN, H3D-mesh, H3D-torus, TESH, and mesh networks by computer simulation. We find that the dynamic communication performance of HTN is better than that of the H3D-mesh, H3D-torus, TESH, and mesh networks.

Mining traversal patterns on the Internet is one of critical issues for exploring the user access behaviors. In this paper, we propose a new data mining scheme for mining frequent trip traversal patterns on the Internet. First, we define a trip traversal as a historical contiguous sequence of web sites or web pages, which were surfed or visited on an information-providing system by one user. Next, we derive all of the maximal trip traversals by analyzing and filtering these collected trip traversals. For mining the large trip traversals from the maximal trip traversals, we present a data mining scheme integrated with the schemes presented in. Here, the extracted large trip traversals can be thought of as the realistic frequent browsed behaviors for most of users either on a web site or on an information-providing system, such as a proxy server. Finally, we implement and design a data mining system to explore the large trip traversal patterns in order to capture user access patterns to some proxy server.

This paper describes a practical Japanese natural language Question Answering system adopting effective selection of dynamic passages, Lexico-Semantic Patterns (LSP), and Predictive Answer Indexing. By analyzing the previous TREC QA data, we defined a dynamic passage unit and developed a passage selection method suitable for Question Answering. Using LSP, we identify the answer type of a question and detect answer candidates without any deep linguistic analyses of the texts. To guarantee a short response time, Predictive Answer Indexing is combined into our overall system architecture. As a result of the three engineering techniques, our system showed excellent performance when evaluated by mean reciprocal rank (MRR) in NTCIR-3 QAC-1.

Nowadays, the World Wide Web is continuing to expand at an amazing rate as a medium for conducting business in addition to disseminating information, and Web users are remarkably increasing. Human activities in virtual space as the Web are producing large volumes of data, and Web data mining to extract information from Web data has become an important research area. In this paper, we examine the features of Web log data and propose a method for transaction identification. We also introduce a new problem of user segmentation and present a method for solving this problem.

Routing security is related to the confidentiality of the route taken by the data transmitted over the network. If the route is detected by the adversary, the probability is higher that the data are lost or the data can be intercepted by the adversary. Therefore, the route must be protected. To accomplish this, we select an intermediate node secretly and transmit the data using this intermediate node, instead of sending the data to the destination node using the shortest path. Furthermore, if we use a number of secret routes from the starting node to the destination node, data security is much stronger since we can transmit partial data rather than the entire data along a secret route. In this paper, the routing algorithm for multiple secret paths on MRNS (Mixed Radix Number System) Network, which requires O(l) for the time complexity where l is the number of links on a node, is presented employing the HCLS (Hamiltonian Circuit Latin Square) and is analyzed in terms of entropy.

A knowledge gap between network operators and system developers in Network Management System (NMS) construction has widened. This has been caused by an expansion of supported business processes and increasingly sophisticated network management functions. This gap makes system development costly and time consuming. Function development, led by operators, is a promising solution to the problems caused by the gap. This type of development should not require an operator to know how to develop NMS. Standard objects may be used to meet this requirement and save time and the cost of NMS construction. However, they are not sufficient to design functions supporting some tasks that are for providing custom services. In this paper, we propose a partial extension package, composed of several object classes. This package is attached to the standard objects to design a custom function. Information processing in a new function can be added, and easily modified, using this package. This package specifies states that invoke the information processing. It also includes objects that add new data without changing standard objects. It makes use of several design patterns in order to weaken coupling to the standard objects. We have applied this package to two programs. One plans maintenance tasks schedules, the other sets threshold values for quality of service. We made use of software metrics to measure their performance in terms of flexibility. The results show that the proposed package continues to make it possible to reuse the standard objects, and makes it easy to modify the behavior of a new function.

Patterns exist in many contexts and can be considered the useful information for decision making. However, many patterns are not directly visible without careful presentation. Here, we describe an interactive visualization approach for browsing patterns in a history of interacting with a computer system. While a user is carrying out his/her business using computers, activities with respect to time and location are captured to determine the situational interactions. We first integrate the timeline and geographical map to create a structure to visualize spatiotemporal events in the interaction history. The spiral-based interactive visualization technique, presented in this paper, is then used to derive patterns according to the user-specified different spatial viewpoints on the map. In this study, we demonstrate how patterns can be used as visual statements for the analysis of a spatiotemporal data set in the information visualization.