Kazutoshi Fujikawa

Proposal and Evaluation of a Dynamic Resource Allocation Method Based on the Load of VMs on IaaS

Recently, Cloud computing has emerged as a new computing paradigm on the Internet. Cloud computing facilitates flexible and efficient computer resource management via virtualization technologies at anytime and from anywhere, so that users can add and/or delete IT resources. Users can set up and boot the required resources and they have to pay only for the required resources. However, they have to spend a considerable amount of time and money to design, set up, boot, and monitor their resources. Thus, in the future, providing a mechanism for efficient resource assignment and management will be an important objective of cloud computing. In this paper, we propose a dynamic resource allocation method based on the load of VMs on IaaS, abbreviated as DAIaS. This method enables users to dynamically add and/or delete one or more instances on the basis of the load and the conditions specified by the user. We implement a prototype to evaluate the effectiveness and efficiency of DAIaS. Furthermore, we perform an experiment to extract the prototype on a real cloud service, namely, Amazon EC2.

Location-aware service discovery on IPv6 GeoNetworking for VANET

Service discovery is an essential component for applications in vehicular communication systems. While there have been numerous service discovery protocols dedicated to a local network, mobile ad-hoc networks and the Internet, in vehicular communication systems, applications pose additional requirements; They need to discover services according to geographical position. In this paper, we propose a location-aware service discovery mechanism for Vehicular Ad-hoc NETwork (VANET). The proposed mechanism exploits IPv6 multicast on top of IPv6 GeoNetworking specified by the GeoNet project. Thanks to the GeoBroadcast mechanism, it efficiently propagates service discovery messages to a subset of nodes inside a relevant geographical area with encapsulating IPv6 multicast packets. We implemented the mechanism using CarGeo6, an open source implementation of IPv6 GeoNetworking. Our real field evaluation shows the system can discover services with low latency and low bandwidth usage in VANETs.

A Dynamic QoS Adaptation Mechanism for Networked Virtual Reality

In this paper, we propose a dynamic QoS adaptation mechanism for the networked virtual reality (VR) system to improve responsiveness to the users and introduce a live video into an networked VR system. To keep presentation quality as much as possible from point of view of user’s perception when network and local system resources are going to starve, we introduce the notion of an importance of presence (IoP) of objects. In case of the resource starvation, our VR system reduces QoSs of both Computer Graphic (CG) objects and Video objects based on IoP. That is, the quality of the object whose IoP is the lowest in the virtual space is reduced.

A quality control mechanism for networked virtual reality system with video capability

Introduction of motion video including live video into networked virtual reality systems makes virtual spaces more attractive. To handle live video in networked virtual reality systems based on VRML, the scalability of networked virtual reality systems becomes very important on the Internet where the performance of the network and the end systems varies dynamically. We propose a new quality control mechanism suitable for networked virtual reality systems with live video capability. Our approach is to introduce the notion of the importance of presence (IoP) which represents the importance of objects in virtual spaces. According to IoP, the degree of the deterioration of object presentation will be determined in case of the starvation of system resources.

QoS mapping for a networked virtual reality system

We developed a networked virtual reality system on which one could have live videos with high interactive usage. However, since a client in our system requires both live videos and computer graphics objects continuously from a server while it is rendering the current frame of the virtual world, a quality of the presentation of the virtual space depends on the current available system resources on the client as well as network resources. In this paper, we discuss the notion of QoS for a networked VR system as an application level QoS which is based on the notion of an importance of presence of objects in a virtual space calculated by a distance from a current users position to the object and an angle from the users perspective to the object. Then, we show a heuristic mapping mechanism of the application level QoS to a network level QoS which determines the allocation of bandwidth of videos and CG objects to maximize the presentation quality. We adopt bandwidth as an example of network level QoS. We are developing our prototype system on the SGI Indigo utilizing the IRIS Performer with the Virtual Reality Modeling Language 2.0.

Networked Telepresence System Using Web Browsers and Omni-directional Video Streams

In this paper, we describe a new telepresence system which enables a user to look around a virtualized real world easily in network environments. The proposed system includes omni-directional video viewers on web browsers and allows the user to look around the omni-directional video contents on the web browsers. The omni-directional video viewer is implemented as an Active-X program so that the user can install the viewer automatically only by opening the web site which contains the omni-directional video contents. The system allows many users at different sites to look around the scene just like an interactive TV using a multi-cast protocol without increasing the network traffic. This paper describes the implemented system and the experiments using live and stored video streams. In the experiment with stored video streams, the system uses an omni-directional multi-camera system for video capturing. We can look around high resolution and high quality video contents. In the experiment with live video streams, a car-mounted omni-directional camera acquires omni-directional video streams surrounding the car, running in an outdoor environment. The acquired video streams are transferred to the remote site through the wireless and wired network using multi-cast protocol. We can see the live video contents freely in arbitrary direction. In the both experiments, we have implemented a view-dependent presentation with a head-mounted display (HMD) and a gyro sensor for realizing more rich presence.

A Server Selection Method Based on Communication Delay and Communication Frequency among Users for Networked Virtual Environments

In Net-VEs, since a user moves about virtual space and interacts with other users, Net-VE system needs to take into consideration the position of the user in virtual space, in addition to the state of a network and a server. In this paper, we propose a new server selection method that can choose the servers from the point of view of both communication delay concerned with the position on a network and the communication frequency concerned with the position on virtual space. Our proposed method collects users with high communication frequency as one group and lets users of the group connect with the same server. In addition, a server where users connect is chosen based on the communication delay from the user in a group to the server. Thus, our Net-VE system can choose servers on which users can exchange updates quickly.

Streaming Mobile Multimedia Optimization for Video-Conferencing Scenarios

Video conferencing in mobile environments involves real time streaming information among mobile nodes connected within a wireless environment. This kind of framework is difficult to deal with, because of its concrete requirements. In this paper, we propose an architecture based on adaptive applications that will change their behavior depending on the network information gathered by the operating system. We will demonstrate that we can provide a better QoS for video conferencing scenarios with minimum costs while maintaining a high portability.

Implementation and Evaluation of a Memory Management System for IPv6 Wireless Sensor Networks

There have been many wireless sensors equipped IEEE 802.15.4. ZigBee, the most representative upper layer protocol of IEEE 802.15.4 is non-IP-based. However an IPv6 protocol called 6LoWPAN is currently being discussed by the IETF. Until now, IP stacks have generally been too large for sensor devices, which have weak calculating ability. Thus, most of wireless sensor networks are non-IP networks. The Internet, of course, generally are using IP. If we can use IP with wireless sensor networks, we can reap the benefits of the IPpsilas superior technology. Researches in this field aim to develop wireless sensor networks using IPv6 and obtain the efficiency of IP-capable wireless sensor networks. However, problems with the buffer overflow have been reported in some implementations of 6LoWPAN. In this paper, we propose a memory buffer control mechanism for 6LoWPAN, and evaluate an implementation of a 6LoWPAN protocol stack using this mechanism. Results of this implementation have shown that the buffer control mechanism worked efficiently.

AnaVANET: An Experiment and Visualization Tool for Vehicular Networks

The experimental evaluation of wireless and mobile networks is a challenge that rarely substitutes simulation in research works. This statement is even more evident in vehicular communications, due to the equipment and effort needed to obtain significant and realistic results. In this paper, key issues in vehicular experimental evaluation are analyzed by an evaluation tool called AnaVANET, especially designed for assessing the performance of vehicular networks. This software processes the output of well-known testing tools such as ping or iperf, together with navigation information, to generate geo-aware performance figures of merit both in numeric and graphical forms. Its main analysis capabilities are used to validate the good performance in terms of delay, packet delivery ratio and throughput of NEMO, when using a road-side segment based on IPv6 GeoNetworking.