In this paper, we focus on the traveling salesman problem (TSP) that is a typical combinatorial optimization problem, and propose a method for solving it with applying deep learning. This method features learning the image of the optimal tour by a convolutional neural network to acquire the Good-Edge Distribution whose edges could be included in the optimal solution. It also conducts neighborhood search by using Good-Edge Value that is an evaluation of each edge calculated from the distribution. We show experimentally that this method improves the quality of solutions.

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Consultant-guided search (CGS) is a recent metaheuristic method. This approach is an algorithm in which a virtual person called a client creates a solution based on consultation with a virtual person called a consultant. In this study, we propose a parallel CGS algorithm with a genetic algorithm’s crossover and selection, and calculate an approximation solution for the traveling salesman problem. We execute a computer experiment using the benchmark problems (TSPLIB). Our algorithm provides a solution with less than 3.3% error rate for problem instances using less than 6000 cities.

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Meta-heuristics is available for the combinatorial optimization problem and its ability has been developed. Especially, the Consultant Guided Search-Particle Swarm Optimization (CGS-PSO) hybrid method has showed powerful performance. CGS-PSO hybrid method tunes parameters of CGS algorithm with PSO algorithm adaptively. In this study, in order to enhance the CGS-PSO hybrid method, we propose the new parallel parameter tuning method with sharing parameters between processes. We benchmark the proposed method in the convergence speed and the error rate for instances of TSPLIB. As a result, we show the proposed method is superior in terms of the convergence speed.

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Language：Japanese  

Meta-heuristics is available for the combinatorial optimization problem and its ability has been developed. The Swarm Intelligence (SI) with the adaptive parameter tuning by the Particle Swarm Optimization algorithm shows powerfull results. In this study, some SI algorithms apply the adaptive parameter tuning by the PSO algorithm. We perform simlulation experiments, and evaluate the ability of SI enhanced by the PSO. In addition, we consider the important parameters for some instances, and analyze its effectiveness, comparing the enhanced SI with the SI algorithm set the static parameters.

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Language：Japanese  

Metaheuristic algorithms have been studied as a method for sloving combinatorial optimization problems. Recently, the Consultant-Guided Search(CGS) for solving the Traveling Salesman Problem(TSP) has been proposed. In this paper, we propose a parallel method which assigns virtual consultants and virtual clients of the CGS to processes of computers, and calculates an approximation solution effectively for the TSP. In addition, we introduce the island model to increase the diversity of the solution. We execute computer experiments with the benchmark instances(TSPLIB) by 10 quad-core computers. Our algorithm provides a solution with less than 5% error rate for problem instances of 5000 cities.

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Other Link： http://id.nii.ac.jp/1001/00147418/

Japan is known as one of the world's most quake-prone countries. Many commuters are stranded when major earthquake occurs in Japan. Most of the stranded commuters cannot use mobile devices to connect to the Internet because of failure of other communication channels. In this paper, we propose sharing GPS data over DTN (Delay Tolerant Network) to facilitate the generation near real-time maps and support for stranded commuters in the event of earthquake disasters. In order to evaluate the network performance, we have carried out simulations using map data for Asahi Ward, Osaka City in Japan. The results of the simulation indicate that the proposed method could achieve desired accuracy considering reasonable time constraints for near real-time mapping.

DOI： 10.1007/s12626-015-0055-2

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

In a previous paper, we proposed a rescue support system for victims buried in an earthquake disaster by constructing an ad-hoc network using home-server based smart homes. However, this system has the following two problems: i) it cannot ensure sufficient density of home servers to realize adequate WLAN coverage, ii) the system does not consider areas in which home servers cannot be used such as parks and factories, for example. In this paper, we propose a new method using a delay tolerant network (DTN) technique. In this method, rescuers (such as rescue teams) with mobile devices relay information between disconnected networks by walking around during rescue activities. For a performance evaluation, we performed simulation experiments using a map of Abenoku, Osaka. From our results, we show that the proposed method increases the information acquisition rate, and that the network can be maintained. We also quantitatively show the penetration rate of smart homes needed for our system. In addition, we show that the rescue request system is more effective than other systems, and the method with the mobile device relay is better than without this method.

DOI： 10.1587/transcom.E98.B.1832

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Language：Japanese  

In this paper, we propose a dynamic region division and binding algorithm of a P2PMMORPG(MMORPG:Massively Multiplayer Online Role Playing Game). The P2P MMORPG divides a virtual space into regions and sets a peer to manage the region as a management node. If a peer takes over load, delay or interruption of the game occurs. So, it is necessary to divide regions in order to distribute the load. We dynamically decompose regions by detecting the movement of players and providingthresholds that is upper and lower limits of the number of players in each region. By our algorithm, it is possible to perform load balancing that corresponds to issues of P2P communication type. We show the proposed algorithm reduces the total load than the conventional algorithms by simulation experiments.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

Metaheuristic methods have been studied for combinational optimization problems for some time. Recently, a Consultant-Guided Search (CGS) has been proposed as a metaheuristic method for the Traveling Salesperson Problem (TSP). This approach is an algorithm in which a virtual person called a client creates a solution based on consultation with a virtual person called a consultant. In this research, we propose a parallel algorithm which uses the Ant Colony System (ACS) to create a solution with a consultant in a Consultant-Guided Search, and calculate an approximation solution for the TSP. Finally, we execute a computer experiment using the benchmark problems (TSPL1B). Our algorithm provides a solution with less than 2% error rate for problem instances using less than 2000 cities.

DOI： 10.1587/trnasfun.E97.A.1728

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

A lot of people have suffered and died due to sudden disasters (fire, earthquake, terrorism, etc) in the world. In sudden disasters, it is very important for evacuees to find out appropriate evacuation routes. We previously proposed the evacuation support system named as Emergency Rescue Evacuation Support System (ERESS). This system is based on MANET and aims to dramatically reduce the number of victims in sudden disasters. This paper deals with the evacuation route search which is one of the most important functions of ERESS. In this paper, we propose a new evacuation route search algorithm for route distribution of evacuees groups in fire disasters. In this algorithm, evacuees can evacuate more safely and immediately by avoiding the congestion passage. To show the validity of the proposed algorithm, we carry out performance evaluations by computer simulations. As the results, we show that more evacuees can evacuate effectively compared with the previous route search algorithm.

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Language：Japanese  

We propose a rescue support system for victims in an earthquake disaster, using home servers of smart homes that realize a comfortable home environment by sensing, and aim to achieve this system. In this paper, we consider the method of data delivery to achieve our system. Our proposed system is starting communication between neighboring home servers, and set up ad-hoc networks, when it detects the Earthquake Early Warning. By sharing information with each other through communication, each home server identies buried victims etc. by information such as being at home after the earthquake, and generates a Rescue Request MAP. As we can get the Rescue Request MAP by mobile devices from home servers, this system can eciently help rescue operations by rescuers and local residents. To achieve our proposal, we must consider a disconnected communication problem, because the home server can't be put in park area, factory area, and so on. Therefore, we propose to set repeaters to aid communication between home servers. In order to evaluate performance, we measure actual experiments for wireless LAN communication as preliminary experiments, and perform simulations with modeling systems based on actual experiment results. From our simulations, we quantitatively show the penetration of smart home that needed to achieve this proposal, and find that this system can maintain in the low penetration rate by setting repeaters. We also show amount of information a user with a mobile device gets, when the user walk around freely for collecting a Rescue Request MAP. As a result, we found that our proposed system can be maintained in the penetration rate of 50%.

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Other Link： http://hdl.handle.net/10112/7840

The important things about managing literatures in laboratories are “Sharing literatures between members” and “Easy to search literatures and to cite them in papers”. Currently, many literature management tools have developed, but not enough to satisfy the above conditions. In this paper, we develop the literature management system “bole” that specializes in the use of laboratories. The proposed system is developed as the web application, and when literature information is registered in the system, research area, comment, evaluation, and so on about literatures are registered as additional information in order to facilitate sharing of literature information in laboratories. BibTEX is used in our laboratory to write a paper, therefore we develop functions convenient to use BibTEX, for example citation key can be copied with one click. We show the utility of the proposed system to share literature information easily in the laboratory, and efficiently to write the papers.

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Language：Japanese  

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Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

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Other Link： http://hdl.handle.net/10112/7999

Language：English   Publishing type：Research paper (international conference proceedings)  

Nowadays, computing resources have taken tens percent of utilization at busy time for increasing computing power. However, the virtual machine (VM) technology is effective to the use of computing resources. Besides, the vulnerable services in VM prevent the affect of the other VM attacks. For example, Amazon has applied the VM method to run in real machine (Host OS) independently but attackers can retrieve data by CPU and memory dump software. Therefore this study suggests a method to improve the access virtual Trusted Platform Module (vTPM) implemented in Xen software to keep the server system safely. Furthermore, we implement and evaluate this method. © 2010 IEEE.

DOI： 10.1109/ICPPW.2010.44

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Spam mail is a nuisance for most Internet users. Recently, spam mail has been shown to cause large economic losses in industries. The purpose of this paper is to quantitatively analyze the negative economic effects caused by spam mail. Concretely, we calculate the loss of GDP in Japanese industries through a production function. In addition, we examine whether or not a difference exists in economic loss by spam mail across industries. Finally, we discuss the effectiveness of spam mail countermeasures.

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE COMPUTER SOC  

From the view of economics, the authors analyze the disadvantages of Spam mail. For this purpose, we introduce a production function model and estimate the effect of Spam mail. As a result, we find that the existence of Spam mail decreases not only the level of the GDP (Gross Domestic Product), which is about 464 billion yen (0.1% of the Japanese GDP), but also reduces labor productivity This implies that the existence of Spam mail directly and indirectly damages the entire economy Therefore, we suggest a full-fledged introduction of "Outbound Port 25 Blocking" to all ISPs (Internet Service Providers) and "Sendmail Authentication" to all firms as effective Spam mail countermeasures.

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：ACTA PRESS ANAHEIM  

Content Distribution Networks (CDNs) have proliferated rapidly with the growth in network bandwidth and the variety of content files. The CDN service is one of the most popular Web services from Internet Service Providers (ISPs), since most ISPs are currently striving to provide additional services besides their original Internet access service.
The Internet has seen an explosive increase in the number of users, which causes network servers to become overloaded, and we are currently facing several serious issues, such as declining reliability, increased response time, and so on. The replicated allocation of content files on cache servers for load-balancing is known as an effective solution to overcome these issues. In CDNs, one of the most important problems is how we allocate cache servers and content files while considering trade-offs between the cost, reliability, and delay.
In this paper, we examine an example of the CDN service in an ISP "BBit-Japan", which is one of the biggest CDN service providers in Japan. We apply this example to the cache server and content allocation model which we have proposed. This optimization model introduces 0-1 integer programming to determine the optimal allocation of cache servers and content files. In this optimization model, we aim to maximize the reliability of the whole system subject to restrictions of cost and delay, and in considering trade-offs between reliability, cost, and delay. The use of this optimization model makes it possible to show precisely how they can properly allocate cache servers and content files at limited cost and within permissible delays to the CDN service providers.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SCRIPTA TECHNICA-JOHN WILEY & SONS  

The branch and bound method is a solution method which is used in deriving the optimal solution for combinatorial optimization problems. The parallel implementation of the branch and bound method is considered, aiming at expansion of the range of applicable problems. With recent advances in PCs and network technology, there have been studies of the parallel branch and bound method in a meta-computing environment, which differs from conventional parallel computers. It is difficult in the branch and bound method to identify the effective strategy for each sample problem beforehand, since the behavior of the program is different in each case. In this study, the following method is considered in order to determine whether it is possible to foresee the effective strategy. Some feasible problems in the meta-computing environment are first solved by several different strategies, and the effective strategy is identified. Then, the identified strategy is used to reduce the later processing time. As a real sample problem, a program for the parallel branch and bound method was prepared to solve the traveling salesman problem. The scheme for branch variable selection was varied. The method that derives an optimal solution, and the method that searches all optimal solutions with the same evaluation value are compared in terms of computation time and acceleration. (c) 2005 Wiley Periodicals, Inc.

DOI： 10.1002/ecjb.20244

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

Content Distribution Networks (CDNs) are highly advanced architectures for networks on the Internet, providing low latency, scalability, fault tolerance, and load balancing. One of the most important issues to realize these advantages of CDNs is dynamic content allocation to deal with temporal load fluctuation, which provides mirroring of content files in order to distribute user accesses. Since user accesses for content files change over time, the content files need to be reallocated appropriately. In this paper, we propose a cost-effective content migration method called the Step-by-Step (SxS) Migration Algorithm for CDNs, which can dynamically relocate content files while reducing transmission cost. We show that our method maintains sufficient performance while reducing cost in comparison to the conventional shortest-path migration method. Furthermore, we present six life cycle models of content to consider realistic traffic patterns in our simulation experiments. Finally, we evaluate the effectiveness of our SxS Migration Algorithm for dynamic content reconfiguration across time.

DOI： 10.1093/ietcom/e88-b.12.4598

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE COMPUTER SOC  

In the conventional WWW search or P2P file sharing systems, users search for some information by using the Explicit Information such as keywords, addresses or content names. However, it is very difficult to obtain real-time information immediately just after serious accident (i.e. Fires, Earthquake, Explosion by terrorism, Traffic accidents and so on) happens suddenly. The conventional information systems, whether it is centralized nor distributed, cannot support user accesses, since they cannot provide any contents with the Explicit Information, in such short time.
In this paper, we propose a new communication scheme named COC - Content Oriented Communications. In COC, distributed information systems don't observe the Explicit Information (keywords, addresses, content names, etc.) but the Implicit Information (locations, time, speed, etc.). This is why we call our system Content Oriented. In this paper, we introduce COC, which enables us to decrease the personal damage of a disaster in a local area where the disaster occurs by searching and getting some information for the evacuation.

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Language：Japanese  

Internet service providers operated in local area have made advanced information systems and promoted local community in their area. However recently, while providers operated in nationwide expand their service area, local providers are facing operational difficulty. In this paper, we measure technical efficiencies for internet service providers using data envelopment analysis. We obtain the data by our questionnaire survey. Then we test the difference of the level of calculated efficiency scores between nationwide providers plus providers served in three metropolitan areas (Tokyo, Aichi, and Osaka) and local providers, using Mann-Whitney's rank sum test.The result says there is a statistical difference at 5% significance level between the two groups. We can obtain the fact that local providers should use IT assets more efficiently than nationwide or three metropolitan providers. Following this result, we suggest some implications from the viewpoints of a scheme of subsidy, M&A and price of backbone usage.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

Mirroring of network servers has been considered to be effective for load balancing. However, the cost of setting up new mirror servers is enormously high. In this paper, we propose a dynamic file allocation model with a simple mirroring function for handling significant changes of network traffic in the Internet. According to the load fluctuation, we can dynamically reallocate files using this model. We show that our model accomplishes satisfactory performance and reduces cost by adding a simple mirroring function to all existent servers instead of setting up mirror servers afresh.

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

The anycast communication protocol is to select the best server and the best route for a particular client from a group of replicated servers with the same contents. As users have come to demand contents with high QoS, the necessity to support the anycast communications in QoS networks has grown. In this paper, we propose a server and route selection method with application-level QoS-based anycast protocol. The protocol we propose has the following advantages. 1) The latest server and route information can be constantly acquired through distributed resource management by E-BB. 2) The server and route selection algorithm enable us to consider both the server load and network load simultaneously. 3) High reliability can be guaranteed by decentralized control.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

In this paper, we consider optimal mirror allocation problems for the purpose of load balancing in network servers. We focus on constructing high-reliability networks and propose the optimal mirror allocation model such that the system reliability is maximized subject to costs and delays, in view of the trade-off between the reliability and cost. This optimization model is capable of dealing with various kinds of network topologies, although for simplicity, we assume the read-only situation. We formulate this optimization problem into a 0 1 integer programming model, and we use an approximate method for numerical analysis in order to analyze more large-scale systems. Our objective is to find the optimal mirror allocation by solving this model, and to show quantitatively the general characteristics of the load balancing and the improvement of the system reliability by the distributed mirror allocation.

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Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

Parallel branch-and-bound method is one of the algorithms that are applied to combinatorial optimization problems. We consider a distributed computing environment and evaluate the strategy available for such meta-computing architecture. Firstly, we solve partial problem with plural strategies. Further, to find the most promising strategy, we solve the whole problem in the hope to shorten the average processing time. We have developed a parallel branch-and-bound method to solve Traveling Salesman Problem. We consider the relationship between the evaluation to decide one optimum solution and all optimum solutions in the point of processing time and acceleration by changing the selection of branch variables.

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Other Link： http://hdl.handle.net/10112/1872

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

In distributed network systems, it is one of the most important problems how to assign the files to servers in view of cost and delay. It is obvious that there is a trading-off relationship between costs and delays in these systems. In order to evaluate the optimization that the total cost is minimized subject to the total delay, we have presented the Optimal File Allocation Model as 0-1 integer programming, and have investigated the general characteristics in distributed systems. In this model, we have introduced many cost and delay parameters to evaluate the total cost and delay in the system more exactly. In constructing practical systems, it is necessary to investigate the weight and the contribution of each parameter to the total cost. It is very useful to show how to estimate cost and delay parameters on the basis of this analysis. In this paper, we analyze the sensitivity of these parameters and make clear the influence between principal parameters.

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

In this paper, we consider the optimal mirror allocation problems for the purpose of load balance in network servers. We focus on constructing high-reliability networks, and propose the optimal mirror allocation model such that the system reliability is maximized subject to costs and delays, in view of the trading-off relationship between the reliability and cost. This optimization model is capable of dealing with various kinds of network topology. We formulate this optimization problem as a 0-1 integer programming in this model, and we can find the place where each mirror server should be and the concrete assignment of files to mirror servers. Our objective is to find the optimal mirror allocation by solving this model, and to show the general characteristics about the load balance and the Improvement of the system reliability by the distributed mirror allocation, quantitatively.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

This paper introduces an adaptive distributed routing algorithm for the faulty star graph. The algorithm is based on that the n-star graph has uniform node degree n - 1 and is n- 1-connected. By giving two routing rules based on the properties of nodes, an optimal routing function for the fault-free star graph is presented. Far a given destination in the n-star graph, n-1 node-disjoint and edge-disjoint subgraphs, which are derived from n - 1 adjacent edges of the destination, can be constructed by this routing function and the concept of Breadth First Search. When faults are encountered, according to that there are n - 1 node-disjoint paths between two arbitrary nodes, the algorithm can route messages to the destination by finding a fault-free subgraphs based on the local failure information (the status of all its incident edges). As long as the number f of faults (node faults and/or edge faults) is less than the degree n- 1 of the n-star graph, the algorithm can adaptively find a path of length at most d + 4f to route messages successfully from a source to a destination, where d is the distance between source and destination.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

In this paper, we study the optimal allocation of multimedia files in distributed network systems. In these systems, the files are shared by users connected with different servers geographically separated, and each file must be stored in at least one of servers. Users can access any files stored in any servers connected with high-speed communication networks. Copies of the files accessed frequently are to be stored in several servers that have databases. So, it is one of the most important problems how to assign the files to servers in view of costs and delays. Considering these problems in heterogeneous network environments, we present a new system model that covers wide range of multimedia network applications like VOD, GALS, and so on. In these systems, it is obvious that there is trading-off relationship between costs and delays. Our objective is to find the optimal file allocation such that the total cost is minimized subject to the total delay. We introduce a 0-1 integer programming formulation for the optimization problem, and find the optimal file allocation by solving these formulae.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CAMBRIDGE UNIV PRESS  

This paper proposes a distributed fault-tolerant algorithm for one-to-all broadcasting in the one-port communication model on the arrangement graph, Exploiting the hierarchical properties of the arrangement graph to constitute different-sized broadcasting trees for different-sized subgraphs, we propose a distributed algorithm with optimal time complexity and without message redundancy for one-to-all broadcasting in the one-port communication model for the fault-free arrangement graph. According to the property that there is a family of k(n - k) node-disjoint paths between any two nodes, we develop a fast fault-tolerant procedure capable of sending a message from a node to its adjacent nodes on the (n, k)-arrangement graph with less than k(n - k) faulty edges, Combining the fault-tolerant procedure and the optimal broadcasting algorithm, a fault-tolerant broadcasting is achieved on the arrangement graph, It is shown that a message can be broadcast to all the other (n !/(n - k) !) - 1 processors in O (k Ig n) steps if no faults exist on the (n, k)-arrangement graph, and in O(k(2) lgn + k lg(2) n)) steps if the number of faulty edges is less than k(n - k).

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

In this paper, we study allocation problems of multimedia files in distributed network systems. In these systems, the files are shared by users connected with different servers through high-speed communication networks. It is one of the most important problems in distributed systems how to assign the files to servers in view of costs and delays. In these systems, it is obvious that there is a trading-off relationship between costs and delays. Our objective is to find the optimal file allocation such that the total cost is minimized subject to the total delay. In order to evaluate the optimization, we present a system model that can covers a wide range of multimedia network applications such as VoD (Video on Demand), corporation information networks, and so on. We introduce a 0-1 integer programming formulation for the optimization problem. We find the optimal file allocation by solving these formulae, and quantify the general tendency in distributed systems. Moreover, we make a comparison between the exhaustive search and the approximate method that we use for optimization.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER-VERLAG BERLIN  

This paper presents an adaptive distributed fault-tolerant routing algorithm for the n-star graph. Based on the local failure information and the properties of the star graph, the algorithm can make routing decisions without deadlock and livelock. After faults are encountered, the algorithm routes messages to a given destination by finding a fault-free n-1-star graph. As long as the number f of faults (node faults and/or edge faults) is less than the degree n - 1 of the n-star graph, the algorithm can adaptively find a path of length at most d + 6f to route messages from a source to a destination, where d is the distance between tow nodes.

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE COMPUTER SOC  

This paper introduces an adaptive distributed routing algorithm for the faulty star graph. By giving two routing Pules based on the properties of nodes, an optimal routing function for the fault-free star graph is presented. For a given destination in the n-star graph, n - 1 node-disjoint and edge-disjoint subgraphs, which are derived from n - 1 adjacent edges Elf the destination, can be constructed by applying this routing function and the concept of Breadth First Search. When faults are encountered, the algorithm can route messages to the destination by finding a fault-free subgraphs based on the local failure information. As long as the number f of faults (node faults and/or edge faults) is less than the degree n - 1 of the n-star graph, the algorithm can adaptively find a path of length at most d + 4f to route messages successfully from a source to a destination, where d is the distance between two nodes.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER-VERLAG BERLIN  

In this paper, we propose a distributed algorithm for one-to-all broadcasting on the arrangement graph. The algorithm exploits the rich topological properties of the (n, k)-arrangement graph to constitute the broadcasting binary tree and works recursively When faulty links are encountered, the concepts of node-disjoint paths and virtual paths are used to deal with the broadcasting procedure. It is shown that the message can be broadcast to all n!/(n-k)! processors in O(k lg n) steps for fault-free mode, and in O(k(k + Ig n)) for less than k(n - k) - 1 faulty links.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER-VERLAG BERLIN  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEICE-INST ELECTRON INFO COMMUN ENG  

Roundness is one of the most important geometric measures for circular objects in the process of mechanical assembly. It is the amount of variation in a circular size which can be permitted. To compute roundness, the authors have already proposed an exact polynomial-time algorithm whose time complexity is O(n2). In this paper, we show that this roundness algorithm can be improved more efficiently, by introducing the deletion of the unnecessary points, in practical applications. In addition, the computational experience of this revised algorithm is also resented.

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Other Link： http://hdl.handle.net/10112/1867

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Other Link： http://hdl.handle.net/10112/1802

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Language：Japanese   Publisher：関西大学先端科学技術推進機構  

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Language：Japanese   Publisher：関西大学先端科学技術推進機構  

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Language：English   Publisher：The Institute of Electronics, Informationa and Communicaton Engineers  

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Language：Japanese   Publisher：Information Processing Society of Japan (IPSJ)  

Wireless Sensor Networks are used to monitor the various events. However, sensor nodes are usually relies on energy source to the battery, so lifetime of the sensor nodes is limited. Duty Cycling is used to reduce energy consumption in wireless sensor networks. Therefore, lifetime of sensornodes is extended, but if relay of data packets is concentrated on some nodes, the network lifetime becomes shorter. In this paper, we propose a dynamic duty cycle construction method and a dynamic route determination method for convergecast considering load balancing. We compare with the existing methods and show that network lifetime is extended.

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Language：Japanese   Publisher：関西大学先端科学技術推進機構  

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Language：Japanese   Publisher：関西大学先端科学技術推進機構  

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Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

A lot of people have suffered and died due to sudden disasters (fire, earthquake, terrorism, etc) in the world. In sudden disasters, it is very important for evacuees to find out appropriate evacuation routes. We previously proposed the evacuation support system named as Emergency Rescue Evacuation Support System (ERESS). This system is based on MANET and aims to dramatically reduce the number of victims in sudden disasters. This paper deals with the evacuation route search which is one of the most important functions of ERESS. Currently, there is no method to estimate the locations of terrorist and evacuees. In this paper, we propose a new position estimate algorithm of terrorist by using RFID for evacuation route search in ERESS. In this algorithm, evacuees can evacuate more safely and immediately by avoiding the terrorist. To show the validity of the proposed algorithm, we carry out performance evaluations by computer simulations. As the results, the proposed method can evacuate more evacuees effectively compared with the conventional method.

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)  

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Language：Japanese   Publisher：一般社団法人電子情報通信学会  

近年,スマートホームの研究が盛んに行われている.しかし,居住者一人ひとりを判別し,サポートする研究はほとんどない.我々の研究室では,人体通信タッチタグを用いて,マット型受信機を踏むことにより,入退室者を認識している.このシステムでは,一時退室と帰宅の判断が難しい.本研究では,音声センサを用いて退室者の一時退室,または帰宅を判別する入退室管理システムの実装を行い,実際に研究室で利用した結果を報告する.

CiNii Books

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Language：Japanese   Publisher：Information Processing Society of Japan (IPSJ)  

Japan is known as one of the world's most quake-prone countries. Many commuters are stranded if an earthquake occurs in Japan. Most of the stranded commuters cannot use mobile devices to connect the Internet because of communication failure. In this paper, we propose a Real-time Mapping System based on GPS and wireless LAN function of the mobile devices. In this system, we aim to support for stranded commuters in an earthquake disaster. Using the position information and DTN(Delay Tolerant Network) which are automatically recorded during those users' rescue operations. As performance evaluation, we perform simulations with modeling systems based on maps of Asahi-ku, Osaka. The results from the experiments have shown that our method could achieve certain accuracy within reasonable time.

CiNii Books

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Language：Japanese   Publisher：一般社団法人情報処理学会  

近年，スマートホームの研究が盛んに行われている．しかし，居住者一人ひとりを判別し，サポートする研究はほとんどない．我々の研究室では，人体通信タッチタグを用いて，マット型受信機を踏むことにより，入退室者を認識している．このシステムでは，一時退室と帰宅の判断が難しい．本研究では，音声センサを用いて退室者の一時退室，または帰宅を判別する入退室管理システムの実装を行い，実際に研究室で利用した結果を報告する．

CiNii Books

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Language：Japanese   Publisher：一般社団法人情報処理学会  

近年，スマートホームの研究が盛んに行われている．しかし，居住者一人ひとりを判別し，サポートする研究はほとんどない．我々の研究室では，人体通信タッチタグを用いて，マット型受信機を踏むことにより，入退室者を認識している．このシステムでは，一時退室と帰宅の判断が難しい．本研究では，音声センサを用いて退室者の一時退室，または帰宅を判別する入退室管理システムの実装を行い，実際に研究室で利用した結果を報告する．

CiNii Books

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J-GLOBAL

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J-GLOBAL

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Language：Japanese   Publisher：一般社団法人情報処理学会  

近年，日本での自然災害による被害が深刻化してきている．特に東日本大震災において，地震被害以上に津波被害によって多くの犠牲者がでている．また，地震の場合には通常のインフラ （通信回線，携帯電話網など） を利用できないため，災害時に緊急で構築可能なネットワークが必要である．著者らは，これまでにスマートホーム （スマートハウス） システムを利用して，地震被災時における緊急ネットワーク環境を構築する研究を行っている．本研究では，スマートホームによる緊急ネットワークを利用して，津波被害直前までに被災地域からの避難を支援するシステムを提案する．各避難者は，モバイル端末を利用することで避難経路を確認できる．また，モバイル端末とスマートホーム間で通信することで，モバイル端末の位置情報などから周辺の混雑状況を把握し，その情報を利用することで最適な避難経路を提示する．

CiNii Books

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Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

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Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

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Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

Japan is known as one of the world's most quake-prone countries. Many commuters are stranded if an earthquake occurs in Japan. Most of the stranded commuters cannot use mobile devices to connect the Internet because of communication failure. In this paper, we propose a Real-time Mapping System based on GPS and wireless LAN function of the mobile devices. In this system, we aim to support for stranded commuters in an earthquake disaster. As performance evaluation, we perform simulations with modeling systems based on maps of Abeno-ku, Osaka and Asahi-ku, Yokohama. As a result, our proposed system creates a map almost completely by 1000 mobile devices within l minute in Asahi-ku.

CiNii Books

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Language：Japanese  

CiNii Books

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Language：Japanese  

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)   Publisher：The Institute of Electronics, Information and Communication Engineers  

In the event of disasters such as terrorism and fire, evacuees have to escape the disasters safely and quickly. Our laboratory has been developing of Emergency Rescue Evacuation Support System (ERESS). In ERESS, it is important to provide a safe escape route to the exit to the evacuees. The previous route search algorithm in ERESS did not consider the status of the other evacuees so much. But we need to consider all the surrounding circumstances. In this paper, we propose a Real-Time Cooperative Evacuation Route Search in ERESS. By using this algorithm, it is able to prevent the congestion of the passage. We show the validity of the proposed algorithm by computer simulation. As a result, we show more evacuees can evacuate than the previous route search algorithm.

CiNii Books

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Language：English  

CiNii Books

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Language：Japanese  

CiNii Books

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Language：Japanese   Publisher：FIT(電子情報通信学会・情報処理学会)運営委員会  

CiNii Books

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Language：Japanese   Publisher：Osaka City University  

CiNii Books

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Other Link： http://dlisv03.media.osaka-cu.ac.jp/il/meta_pub/G0000438repository_KJ00006658339

Language：Japanese   Publisher：Information Processing Society of Japan (IPSJ)  

PC grid is one of the parallel computing system, and it makes the best use of idle PCs. In this paper, we propose an implementation of a PC grid system with migration function. If a person use the PC running a grid job, the migration function moves it to another idle PC Furthermore, the time of migration with virtual machine depends on the fixed memory size. So, we propose a method to carry out jobs in considering of the memory size.

CiNii Books

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Other Link： http://id.nii.ac.jp/1001/00061899/

Language：Japanese  

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Language：Japanese   Publisher：Information Processing Society of Japan (IPSJ)  

The traveling salesperson problem is one of the typical examples in the combinational optimization problems and many researches have been conducted so far. In this paper, the tabu search method which is one of the meta-heuristics method for this problem is parallelized. Especially we focus on the communication needed to share the information regarding to "the edge exchange" between processes, and examine a method which enable to share the informations more efficiently. The computing examination has been done by several evaluations from the result of running the parallel tabu search programs.

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Other Link： http://id.nii.ac.jp/1001/00033188/

Language：English   Publisher：Forum on Information Technology  

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Language：English   Publisher：関西大学学術フロンティア・センター  

CiNii Books

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Language：English   Publisher：The Institute of Electronics, Information and Communication Engineers  

In this paper, we consider optimal mirror allocation problems for the purpose of load balancing in network servers. We focus on constructing high-reliability networks and propose the optimal mirror allocation model such that the system reliability is maximized subject to costs and delays, in view of the trade-off between the reliability and cost. This optimization model is capable of dealing with various kinds of network topologies, although for simplicity, we assume the read-only situation. We formulate this optimization problem into a 0-1 integer programming model, and we use an approximate method for numerical analysis in order to analyze more large-scale systems. Our objective is to find the optimal mirror allocation by solving this model, and to show quantitatively the general characteristics of the load balancing and the improvement of the system reliability by the distributed mirror allocation.

CiNii Books

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Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

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Language：Japanese   Publisher：関西大学工業技術研究所  

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Language：English   Publisher：The Institute of Electronics, Information and Communication Engineers  

This paper presents a depth first search-based routing protocol for arrangement interconnection network in the presence of faulty links.(n,k)-Arrangement graph,a superset of Star graph,is a good candidate for parallel computers.This topology offers facilities for the designer in working with size,degree,and diameter.These parameters are so essential in practical situations.The protocol exploits fully the properties of this network,and attempts to route a message to the destination via optimal path(shortest path). Also,if optimal paths are blocked our algorithm looks for the available shorter path from the destination.In addition,we give the mathematical expression for the probability of routing messages traveling over optimal paths.The results show that our algorithm routes a message with high probability for any selection of the parameters n and k.

CiNii Books

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Venue：Portland, OR, USA  

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Venue：大阪大学  

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Venue：札幌市  

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Venue：札幌市  

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Venue：Kyoto, Japan  

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Venue：福岡大学  

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Venue：福岡大学  

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Venue：福岡大学  

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Venue：福岡大学  

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Venue：Hida Takayama, Japan  

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Venue：金沢大学  

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Venue：金沢大学  

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Venue：金沢大学  

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Venue：金沢大学  

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Venue：University of Essex, Southend, UK  

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Venue：Eugene, OR, USA  

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Venue：沖縄科学技術大学院大学  

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Venue：沖縄科学技術大学院大学  

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Venue：関西大学, 大阪  

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Venue：関西大学, 大阪  

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Venue：東京都市大学, 東京  

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Venue：Quebec City, Canada  

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Venue：Quebec City, Canada  

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Venue：名古屋  

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Venue：名古屋  

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Venue：奈良  

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Venue：札幌  

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Venue：Tokyo  

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Venue：大阪  

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Venue：Hawaii, USA  

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Venue：大阪  

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Venue：福岡  

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Venue：福岡  

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Venue：福岡  

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Venue：北見  

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Venue：北見  

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Venue：島原  

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Venue：Bangkok, Thailand  

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Venue：Melbourne, Australia  

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Venue：San Francisco  

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Venue：San Francisco  

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Venue：仙台  

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Venue：仙台  

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Venue：Barcelona  

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Venue：京都  

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Venue：横浜  

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Venue：横浜  

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Venue：東京  

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Venue：福岡  

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Venue：福岡  

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Venue：福岡  

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Venue：福岡  

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Venue：Roma, Italy  

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Venue：東京大学  

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Venue：宮崎  

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Venue：京都大学  

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Venue：Las Vegas, USA  

In a previous paper, we proposed a rescuesupport system for victims buried in an earthquake disasterby constructing an ad-hoc network using home-server smarthomes. However, this system has the following two problems:i) it cannot ensure sufficient density of home servers fora WLAN communication range, ii) the system does notconsider areas in which home servers cannot be used suchas in parks and factories, for example. In this research,we propose a new method using a delay tolerant network(DTN) technique. In this method, rescuers with mobiledevices relay information between disconnected networks bywalking around during rescue activities. For a performanceevaluation, we performed simulation experiments using amap of Abeno-ku, Osaka. From our results, we show thatthe proposed method increases the information acquisitionrate, and the network can be maintained. In addition,we quantitatively show the penetration of the smart homeneeded for our system.

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Venue：Crete, Greece  

In this paper, we present a heuristic algorithm based on the Branch andBound (BB) method for the Traveling Salesman Problem (TSP), that isone of the combinatorial optimization problems. We call the proposedmethod the Semi-Fixed Branch and Bound (SFBB) method. The BBmethod is a method to find the optimal solution by searching the whole solutionspace, and consists of branching and bounding. The SFBB methodis composed of three phases. In the first phase, it solves the plural approximatesolutions in parallel by executing metaheuristics algorithms such asTabu Search (TS), Ant Colony Optimization (ACO), and so on. Afterobtaining dozens of the approximate solutions from each algorithm, go tothe next phase. In the second phase, it checks the solutions obtained inthe first phase, and fixes several edges. It divides into a set of candidateedges (Ec) and a set of bounding edges (Eb). Ec is a set of edges emergingin many solutions. Eb is a set of edges rarely emerging in solutions. Inthe third phase, it executes the BB method in parallel for the subproblemwith edges fixed by Ec and Eb. We perform computational experimentsusing the TSPLIB to evaluate the performance of the SFBB method. Inthe experiments, we use the PC cluster in our laboratory. In the parallelalgorithm, we adopt Message Passing Interface (MPI) and Pthreads. Itcommunicates between PCs with MPI, and assigns one thread to eachcore with Pthreads.

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From the view of economics, the authors analyze the disadvantages of Spam mail. For this purpose, we introduce a production function model and estimate the effect of Spam mail. As a result, we find that the existence of Spam mail decreases not only the level of the GDP (Gross Domestic Product), which is about 464 billion yen (0.1% of the Japanese GDP), but also reduces labor productivity. This implies that the existence of Spam mail directly and indirectly damages the entire economy. Therefore, we suggest a full-fledged introduction of ”Outbound Port 25 Blocking” to all ISPs (Internet Service Providers) and ”Sendmail Authentication” to all firms as effective Spam mail countermeasures.

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Content Distribution Networks (CDNs) have proliferated rapidly with the growth in network bandwidth and the variety of content files. The CDN service is one of the most popularWeb services from Internet Service Providers (ISPs), since most ISPs are currently striving to provide additional services besides their original Internet access service. The Internet has seen an explosive increase in the number of users, which causes network servers to become overloaded, and we are currently facing several serious issues, such as declining reliability, increased response time, and so on. The replicated allocation of content files on cache servers for load-balancing is known as an effective solution to overcome these issues. In CDNs, one of the most important problems is how we allocate cache servers and content files while considering trade-offs between the cost, reliability, and delay. In this paper, we examine an example of the CDN service in an ISP ”BBit-Japan”, which is one of the biggest CDN service providers in Japan. We apply this example to the cache server and content allocation model which we have proposed. This optimization model introduces 0-1 integer programming to determine the optimal allocation of cache servers and content files. In this optimization model, we aim to maximize the reliability of the whole system subject to restrictions of cost and delay, and in considering trade-offs between reliability, cost, and delay. The use of this optimization model makes it possible to show precisely how they can properly allocate cache servers and content files at limited cost and within permissible delays to the CDN service providers.

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In the conventional WWW search or P2P file sharing systems, users search for some information by using the Explicit Information such as keywords, addresses or content names. However, it is very difficult to obtain real-time information immediately just after serious accident (i.e. Fires, Earthquake, Explosion by terrorism, Traffic accidents and so on) happens suddenly. The conventional information systems, whether it is centralized nor distributed, cannot support user accesses, since they cannot provide any contents with the Explicit Information, in such short time. In this paper, we propose a new communication scheme named COC, Content Oriented Communications. In COC, distributed information systems don't observe the Explicit Information (keywords, addresses, content names, etc.) but the Implicit Information (locations, time, speed, etc.). This is why we call our system Content Oriented. In this paper, we introduce COC, which enables us to decrease the personal damage of a disaster in a local area where the disaster occurs by searching and getting some information for the evacuation.

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The anycast communication protocol is to select the best server and the best route for a particular client from a groupof replicated servers with the same contents. As users have come to demand contents with high QoS, the necessity to support the anycast communications in QoS networks has grown. In this paper, we propose a server and route selection method with application-level QoS-based anycast protocol. The protocol we propose has the following advantages. 1) The latest server and route information can be constantly acquired through distributed resource management by E-BB. 2) The server and route selection algorithm enable us to consider both the server load and network load simultaneously. 3) High reliability can be guaranteed by decentralized control.

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Grant-in-Aid for Scientific Research

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Grant-in-Aid for International Scientific Research 199904-200103

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Venue：Ishikawa, Japan  

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Venue：Fukuoka, Japan  

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Venue：Amsterdam, The Netherlands  

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Venue：Montréal, Canada  

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Venue：Tokyo, Japan  

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Venue：Tokyo, Japan  

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Venue：Osaka, Japan  

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Venue：Kyoto, Japan  

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