Toshihiko Shimokawa

FCAN : Flash Crowds Alleviation Network

With the rapid spread of information and ubiquitous access of browsers, flash crowd, a sudden, unanticipated surge in the volume of request rates, has become the bane of many Internet websites. This paper models and presents FCAN, an adaptive CDN network that dynamically optimizes the system structure between peer-to-peer (P2P) and client-server(C/S) configurations to alleviate flash crowds effect. FCAN constructs P2P overlay on cache proxy layer to distribute the flash traffic from origin web server. It uses policy-configured DNS redirection to route the client requests in balance, and adopts strategy load detection to monitor and react the load changes. Our preliminary simulation result shows that the system is overall well behaved, which validates the correctness of our basic design and points the way for the future research.

FCAN: Flash Crowds Alleviation Network Using Adaptive P2P Overlay of Cache Proxies

With the rapid spread of information and ubiquitous access of browsers, flash crowds, a sudden, unanticipated surge in the volume of request rates, have become the bane of many Internet websites. This paper models and presents FCAN, an adaptive network that dynamically optimizes the system structure between peer-to-peer (P2P) and client-server (C/S) configurations to alleviate flash crowds effect. FCAN constructs P2P overlay on cache proxy server layer to distribute the flash traffic from origin server. It uses policy-configured DNS redirection to route the client requests in balance, and adopts strategy load detection to monitor and react the load changes. Our preliminary simulation results showed that the system is overall well behaved, which validates the correctness of our design.

Autonomic multi-server distribution in flash crowds alleviation network

The Flash crowds are rapid increase in access to contents of web sites, which makes the web sites inaccessible, leaving the clients with unsatisfied requests. The major shortcoming of flash crowds researches is that they do not assist vital resizing feature of a cloud of the surrogates; the surrogates involved in the alleviation process do not change from the start to the end of flash crowds. Our system, FCAN (Flash Crowds Alleviation Network) is a system to provide resources to web sites to overcome flash crowds. A main feature of FCAN is its dynamically resizing feature, which can adapt to request load of flash crowds by enlarging or shrinking a cloud of surrogate servers used by the web sites. In this paper, we present a new feature of FCAN to support multiple servers which experience different flash crowds simultaneously, and show experiment results with real web log data provided by Live Eclipse 2006.

Component based video communication tool for collaborative virtual environment

This paper treats a component based video communication tool for collaborative virtual environments. Especially the authors propose a new concept and its realization mechanisms for easy construction of distributed 3D graphics applications using video communications, e.g., network meeting, conference, and training in a 3D virtual space. If a software component is represented as a visible, manually operable object, users can make its copy and transfer it to another computer easily and rapidly. If a facility that manages video/audio data is realized as such a object, even end-users can easily and rapidly build networked video communication environments through the copy-and-transfer operation. To clarify an availability of this concept, the authors employ the IntelligentBox system as a research platform. The authors introduced a video communication facility as a software component into the IntelligentBox system. IntelligentBox has provided a network communication facility as a software component. Using these components, it will be possible to build collaborative virtual environments, which support video communications, through copy-and-transfer operations.

Rehabilitation Robot in Primary Walking Pattern Training for SCI Patient at Home

Recently, attention has been focused on incomplete-type spinal cord injury to the central spine caused by pressure on parts of the white matter conducting pathway such as the pyramidal tract. In this paper, we focus on a training robot designed to assist with primary walking pattern training. The target patient of this training robot is one who is relearning the basic functions of the usual walking pattern, especially for patients with the incomplete type SCI to the central spine, who are capable of standing by themselves but are not capable of performing walking motions. From the perspective of human engineering, we monitored the operator’s actions to the robot and investigated the movement of joints of the lower extremities, the circumference of the lower extremities and the exercise intensity with the machine. The concept of the device is to provide mild training without any sudden changes in heart rate or blood pressure, which will be particularly useful for the elderly and disabled.

Scalable server system based on virtual machine duplication in wide area

In the Internet world, server systems play a crucial role in continuously supporting the 24/7 operation of the network. However, some problem issues have been identified with the current server systems on the Internet. In this research, we tackle two of these problems, i.e., the processing power and network bandwidths, and proposed solutions on these issues. In this research, we use virtual machines to solve the above-mentioned problems. Generally, a virtual machine consists of some files which are easy to increase. By duplicating a virtual machine, we can increase processing power of the servers. Likewise, by tapping the wide bandwidth of a high-performance processing server, we can increase the network bandwidth. We call this idea, Server Proliferation. We designed the Virtual Machine Control Protocol (VMCP) to implement Server Proliferation. VMCP has six basic functions; namely, to authenticate users, to get information, to apply information to a virtual machine, to transfer virtual machine, to control virtual machine, and to provide help functions. We implemented a prototype system of VMCP, called PIYO (ProlIferate and Yield Objects). PIYO is a server-client system. Lastly, we evaluated Server Proliferation by using PIYO.

Development of rehabilitation device for standing position weight bearing exercise using Wii balance board

Partial weight-bearing exercise is widely used in rehabilitation for patients with lower limb injuries. It is intended to help patients learn to what degree they can bear weight on the affected limb. General weight scales are widely used for this exercise to measure weight-bearing. These are easy to introduce, but involve some problems. One is that patients cannot easily read the scale to calculate weight-bearing rate. The purpose of this study is to develop a rehabilitation device to address this problem. The device combines the Nintendo Wii Balance BoardTM and a PC. It allows patients to observe the display unit while the device automatically calculates weight-bearing rate. In addition, patients can enjoy exercise with the Game Mode.

Rehabilitation robot in primary walking pattern training for SCI patient: Training robot for home-use based on the experiments of the hospital-use type

Recently, attention has been focused on incomplete-type spinal cord injury (SCI) to the central spine caused by pressure on parts of the white matter conducting pathway such as the pyramidal tract. In this paper, we focus on a training robot designed to assist with primary walking pattern training. The target patient of this training robot is one who is relearning the basic functions of the usual walking pattern, especially for patients with the incomplete type SCI to the central spine, who are capable of standing by themselves but are not capable of performing walking motions. We investigated the movement of joints of the lower extremities, the circumference of the lower extremities and the exercise intensity with the machine. From the experimental results the training robot for home-use based on the experiments on the hospital-use type is proposed. The operating panel, accessibility from wheel chair to the robot and the mechanism were modified for the home-use.

Preliminary Study on World-Wide Implementation of Adaptive Content Distribution Network

A conventional Content Distribution Network (CDN) has a static structure, therefore, it is not an effective solution to a flash crowd, that is a rapid increase in server load caused by a sudden access concentration. We have proposed an adaptive CDN, FCAN (Flash Crowds Alleviation Network), which changes its structure dynamically against flash crowds. In this paper, we verify FCAN on a real world-wide network. Through some experiments, we confirmed that FCAN achieves load distribution effectively.

A Proposal of Request Routing on a Fully Distributed P2P CDN

A peer-to-peer (P2P) Contents Delivery Network (CDN) is a system in which the users get together to forward contents so that the load at a server is reduced. Lately, we have high-speed services for an access to the Internet such as the Asymmetric Digital Subscriber Line (ADSL). Some broadcasters may not have such services because they have only dial-up services and wireless services as PHS and a mobile phone to broadcast live. A problem with P2P CDN is its overhead to construct a distribution tree. It becomes a crucial problem when a broadcaster has only a low-speed access to the Internet, and we propose a P2P CDN system which reduces such an overhead. A server peer is the root peer of a distribution tree and provides users with contents. With the existing algorithms, new peers measure a Round Trip Time (RTT) and a throughput from a broadcaster site when they join the distribution tree. With our algorithm, a new peer sends the server peer a Search Request message which is forwarded throughout the distribution tree until a suitable peer which has enough bandwidth to accomodate is found finally so that the new peer will measure a throughput to that peer. The problem with our algorithm is that as the number of users in the tree increases, the new peer will be preoccupied with measurement, because it may find many suitable peers as its parent candidates. To solve this problem, we introduce a Time To Stop Broadcast (TTSB) on the Search Request message in order to reduce the number of measurement. We have compared the traditional algorithm with ours by simulation. From the simulation results, we have found that our method is effective when a server peer has a low-speed access to the Internet, while the users have a high-speed access.