Improvement of information filtering by independent components selection

We propose an improvement of an information filtering process with independent components selection. The independent components are obtained by Independent Components Analysis and considered as topics. Selection of independent components is an efficient method of improving the accuracy of the information filtering for the purpose of extraction of similar topics by focusing on their meanings. To achieve this, we select the topics by Maximum Distance Algorithm with Jensen‐Shannon divergence. In addition, document vectors are represented by the selected topics. We create a user profile from transformed data with a relevance feedback. Finally, we sort documents by the user profile and evaluate the accuracy by imputation precision. We carried out an evaluation experiment to confirm the validity of the proposed method considering meanings of components used in this experiment. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 163(2): 49–56, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20519     

Information filtering using latent semantics

We propose an information filtering system using latent semantics obtained by Singular Value Decomposition (SVD) and Independent Component Analysis (ICA). Document vectors usually have too many elements. Thus, we are obliged to spend much time applying the ICA for the document vectors. To solve this problem, the present method combines the SVD which is often used for decreasing dimension and the ICA. Before applying the ICA, we represent documents with singular vectors obtained by the SVD. We measure processing times to carry out the ICA without the SVD and the proposed method for comparison of these methods. In addition, we construct a user profile in space consisting of latent semantics obtained by the present method, and discuss accuracy of recommendation. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 165(2): 53–59, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20564     

Properties of quantum gain of coding with information criterion by binary linear codes

In quantum information theory, superadditivity in the capacity of a quantum channel occurs as a special property. We present a method of calculating the mutual information analytically for binary linear codes by using square‐root measurement as the decoding process. Many examples of codes showing the existence of superadditivity in capacity have been given in the past, but the scope of the method was not clarified. In the present paper, we show that the method can be applied to any binary linear codes. We also show that the quantum channel capacity is almost fully attained in a finite codeword length by using approximation to simplex code. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 163(4): 48–57, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20646     

Recycling Technology for a Recycling Society and the Consumer's Expected Consciousness: Recycling from the Viewpoint of Four Items of Home Appliances

The concept of ‘recycling’ was adopted to solve the overuse of resources by mass production and mass consumption of products in the 20th century. In the latter half of the 20th century, all companies started recycling activities slowly but positively, and some of them established their own recycling plants. This article introduces the processes through which used home appliances are made into materials (for reuse), and the machines, facilities, and methods for such reuse, as well as the results of their actual application by the study of a recycling plant. It is expected that this article would motivate the readers for recycling and to consider and feel what we, consumers, should do. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Sociotechnical issues for the ubiquitous information society in 2010

Impact of the ubiquitous information technology on our society is so significant that directing technological development and preparing institutional apparatus are quite important and urgent. The present paper elaborates, with the efforts by both humanity and engineering disciplines, to find the sociotechnical issues of ubiquitous information society in 2010 by inspecting social implications of emerging technology as well as social expectations. In order to deliberate the issues, scenarios are developed that describe possible life in ubiquitous information society. The derived issues cover integrating information technology and the human body, producing smart sharable environment, protecting individual rights, fostering new service business, and forming community. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 165(1): 60–67, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20565     

Autonomous decentralized voltage profile control of super‐distributed energy system using multi‐agent technology

A super‐distributed energy system is a future energy system in which a large part of its demand is fed by a huge number of distributed generators. At one time some nodes in the super‐distributed energy system behave as load, whereas at other times they behave as generator—the characteristic of each node depends on the customers' decision. In such situation, it is very difficult to regulate the voltage profile over the system due to the complexity of power flows. This paper proposes a novel control method of distributed generators that can achieve autonomous decentralized voltage profile regulation by using multi‐agent technology. The proposed multi‐agent system employs two types of agent: a control agent and a mobile agent. Control agents generate or consume reactive power to regulate the voltage profile of neighboring nodes and mobile agents transmit the information necessary for VQ‐control among the control agents. The proposed control method is tested through numerical simulations. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 164(4): 43–52, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20484     

An adaptive and reliable system based on interdependence between agents

A multiagent system (MAS) has recently gained public attention as a technique to solve competition and cooperation in distributed systems. However, MAS's vulnerability due to the propagation of failures prevents its application to a large‐scale system. This paper proposes a general composition technique to improve its reliability easily applied to the existent MAS. The proposed system monitors messages between agents to detect undesirable behaviors (failures). Collecting related information, the system generates global information of interdependence between agents and expresses it in a graph. This interdependence graph enables us to detect or predict undesirable behaviors. This paper also shows that the system can optimize performance of MAS and improve adaptively its reliability under complicated and dynamic environment by applying the global information acquired from analysis of the interdependence graph to a replication system. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 164(1): 62–68, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20517     

A nonlinear model to rank association rules based on semantic similarity and genetic network programing

Many methods have been studied for mining association rules efficiently. However, because these methods usually generate a large number of rules, it is still a heavy burden for the users to find the most interesting ones. In this paper, we propose a novel method for finding what the user is interested in by assigning several keywords, like searching documents on the Web using search engines. By considering both the semantic similarity between the rules and keywords, and the statistical information like support, confidence, chi-squared value, etc. we could rank the rules by a new method named RuleRank, where evolutionary methods are applied to find the optimal ranking model. Experiments show that our approach is effective for the users to find what they want. Copyright © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Position sensorless control for ultrasonic motors based on input voltage information

This paper presents a method of position sensorless control of ultrasonic motors (USM). The position sensorless control method is useful for reducing the cost and size of drive system. The position estimation method is based on the input voltage information of the ultrasonic motor. The characteristic of input voltage versus rotor position is expressed by a quadratic function which is used to estimate a rotor position based on input voltage information. This estimation method, which uses only the drive voltage of the ultrasonic motor, is a very simple algorithm and shows good estimation ability. The parameters of the quadratic function are adjusted by using the recursive least squares method and are obtained on‐line. Since it can correspond to parameter change, the estimated rotor position shows good agreement with the measured rotor position against load torque and motor temperature changes. Sensorless position control is achieved by using the estimated rotor position instead of the measured rotor position. The validity of the proposed method is confirmed by experimental results. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 163(1): 57–64, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20626     

Autonomous dispersed control system for independent micro grid

In this paper, we show an autonomous dispersed control system for independent micro grid of which performance has been substantiated in China by Shikoku Electric Power Co. and its subsidiary companies under the trust of NEDO (New Energy and Industrial Technology Development Organization). For the control of grid interconnected generators, the exclusive information line is very important to save fuel cost and maintain high frequency quality of the electric power supply, but it is relatively expensive in such small micro grids. We contrived an autonomous dispersed control system without any exclusive information line for dispatching control and adjusting supply control. We have confirmed through the substantiation project in China that this autonomous dispersed control system for an independent micro grid has a very satisfactory characteristic from the viewpoint of less fuel consumption and high electric quality. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(1): 28–35, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20618     

Design of controller switching strategy for reusable launch vehicle with elevon jamming failure

When a reusable launch vehicle (RLV) returns to earth, it flies just by gliding without thrust. In this phase, one of the most likely and important faults to occur in the airframe is a jamming of the elevon. To tolerate this failure, the flight control system must keep stability and performance during such a failure. One of the effective ways to overcome this problem is to switch the controllers based on the information of the detected failure in the plant. Generally speaking, the controller must have integrators so as to yield the zero steady‐state error for the controlled output even if there exist some perturbations in the plant dynamics. In this paper, the design of controller switching scenario is addressed especially focusing on the decision of the controller state at the instant of switching the controllers with integrator. Then, the proposed switching scenario is applied to the control of ALFLEX (Automatic Landing FLight EXperiment), which is the automatic landing experimental vehicle being developed for RLV, considering the occurrence of the jamming fault. Some simulations are shown to verify the usefulness of the proposed idea. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 164(2): 80–90, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20356     

Development of education support system for numerical electromagnetic analysis based on server–client model using Java

Among several numerical methods, the Finite Element Method (FEM) has been adopted in various engineering problems. Given this situation, it is necessary to instruct university students in numerical analysis. The authors have designed and implemented a numerical analysis education support system for learning electromagnetic fields with a Graphical User Interface (GUI) based on the client–server model using Java. In this paper, a feasibility study on the student laboratory class in the third year is described. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 163(4): 8–17, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20377     

Extraction of Alpha Activities from an EEG Obtained During Gum Chewing

We propose a method for extracting alpha activities from electroencephalogram (EEG) recordings contaminated by noise from sources such as electromyograms (EMGs), electro‐oculograms (EOGs), or blinking, using independent component analysis (ICA) with simple preprocessing. In the preprocessing, Gaussian signals are connected to the back and front of the original EEG data. Then waveforms of the original EEG are not subjected to any change in shape. In this paper, we extract alpha activities from an EEG recorded while a subject chews gum. As a result, the ICA separation accuracy is often improved, and alpha activities during gum chewing can be successfully extracted. Furthermore, we investigate whether or not the extracted signals satisfy the general characteristics of an alpha rhythm. Copyright © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Power system stabilization control based on the wide area phasor measurement

This paper presents a method of tuning power system stabilizers (PSS) in order to damp low‐frequency oscillations in a multimachine power system based on wide area phasor measurements. The authors have developed a method for detecting interarea low‐frequency modes from measured small oscillations associated with load fluctuations by approximating the oscillations as a coupled vibration model. In this paper, the coupled vibration model is extended to include the effect of PSS. PSS are tuned directly by using the extended model, since the model includes parameters of PSS. The advantage of this method is that steady state phasor fluctuations are available for tuning PSS and assessing the effect of the tuning control. That is, a large disturbance like a line fault is not necessary since the stability of major modes can be investigated directly by using eigenvalues of the extended model. The identification process does not require information on the input to the system for perturbation. Some numerical analyses demonstrate the effectiveness of the method by using phasor dynamical data obtained by a power system simulation package. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 163(1): 16–24, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20640     

Calculation of distribution system voltage and power flow state using measured values

This paper describes a techique of calculating voltage and power flow state of a distribution system using the information measured with two or more switches with sensors installed in a distribution system. In the proposed technique, a set of the power distribution section where two or more switches with a sensor are connected is defined as the large section, and the active power and reactive power consumption in the large section are calculated based on measurement information, voltage (RMS), current (RMS), and power factor. Using the simple distribution system model consisting of the large sections, the power consumption of the large section is calculated by the power flow calculation to separate power consumption and power distribution loss. It is distributed to the small sections that constitute the large section, and detailed power flow calculation is performed. Verification of the proposed technique and basic estimation of the calculation error were performed using the simple power distribution system model. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 164(4): 33–42, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20416     

Realization of acceleration control using multirate sampling method

This paper focuses on the realization of high‐performance motion control based on acceleration control. The characteristics of acceleration control are investigated and the relationship between the performance and sampling frequency of the system is discussed. This paper then describes that a higher sampling frequency is required for acquisition of output information than for updating the input value. Based on this idea, a new multirate sampling method for an acceleration control system is proposed. A disturbance observer for the multirate system is designed by adopting a new definition of disturbance torque. A bilateral system is introduced as a preeminent example of a system that requires robust acceleration control. Both simulations and experiments are performed on the system, and the validity of the proposition is verified by the results. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(4): 72–81, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20507     

A new high‐frequency voltage injection method for sensorless drive of permanent‐magnet synchronous motors with pole saliency

This paper proposes a new sensorless vector control method for salient‐pole permanent‐magnet synchronous motors. In regard to rotor phase estimation, the sensorless vector control method is characterized by a new high‐frequency voltage injection method distinguished from the conventional ones by a unique ellipse shape of the spatial rotation, and by a new PLL method whose input is a high‐frequency current autocorrelated signal. The new vector control method established by two innovative technologies can have the following high‐performance and attractive features: (1) it can allow 250% rated torque at standstill; (2) it can operate from zero to the rated speed under the rated motoring or regenerating load; (3) it accepts instant injection of the rated load even for zero‐speed control; (4) it accommodates a load with huge moment of inertia; (5) phase estimation is very robust against inverter dead time; (6) the computational load for estimating rotor phase is very small, would be the smallest among the methods with comparable performance. This paper presents the new vector control method by focusing on two innovative technologies from its principles to design rules. Usefulness of the new vector control method is verified through extensive experiments. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 164(4): 62–77, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20632     

A distributed autonomous approach for bulk power system restoration by means of multi‐agent system

In recent years, the electric utility industry worldwide has been facing pressure to be deregulated. Also, the risk of blackout in large areas will increase. Actually, it is still vivid in our memory that the northeastern United States and southern Canada suffered the worst blackout in history. Consequently, a method to find the optimal solution rapidly is needed all the more. In this paper, we propose a new multi‐agent method for a bulk power system restoration. In order to demonstrate the capability of the proposed multi‐agent system, it has been applied to a model bulk power system, which consists of three local areas including 12 generating units and 12 loads, and three remote areas with 12 loads. A large number of simulations are carried out on this model network with changing conditions. The simulation results show that the proposed multi‐agent approach is effective and promising. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 164(1): 69–76, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20485     

Improving the health care and public health critical infrastructure

If you think in terms of your lifetime, you may ponder that while the hours, minutes, and seconds of a day have remained the same, the amount of information that you have received, let's say, in the 1980s compared with now, 2008, is drastically different. The size of information received in a day now is larger than what you have received in the past years. The information age has also created a wide range of tools, technologies, and techniques that continuously deliver enormous amounts of data, information, and knowledge. We are increasingly flooded with e-mails that routinely have a plethora of documents (in electronic form) that come in all shapes and forms (multimedia etc.) and more sophisticated types of data and information transmissions from sensing and monitoring devices as well. To compound this issue, there are usually no rules or standards, other than common sense, on how or where we should store all this information or knowledge. The bad news is that, with so much of information flow, it is difficult to filter in just the piece that may be needed at the right time. In many cases, we may not be aware where that information may be or if it exists somewhere at all. However, an information glut caused by a combination of pervasive systems and converging technologies may allow us to get useful and, at times, critical information anywhere and at the right time. In the past decade, with the proliferation of the Internet and the World Wide Web, many past and ongoing efforts have tried to improve the movement from text documents and database records to automated reasoning. This process is critical in particular for information sharing. This article provides a background of knowledge management for public health information infrastructure, followed by an illustration of the complexity of knowledge management for health care. We then present an evolving framework for semantic expression that would enable the sharing and exchange of knowledge in public health.