Kaori Maeda

Dynamic LoD for QoS management in the next generation VRML

A high speed computer network will provide us with new broadband multimedia applications. This paper discusses new functions for the next generation VRML (Virtual Reality Modeling Language) over high speed computer networks. The LoD (Level of Detail) of 3D objects is the most important function for rendering scenes dynamically while managing the QoS (Quality of Service). New requirements for the next generation VRML are discussed. We present Differential VRML (DVRML) in order to update scene graphs dynamically, and describe principles of the LoD function based on the DVRML.

An adaptive maintenance of hierarchical structure in ad hoc networks and its evaluation

Hierarchical routing is effective for large ad hoc networks. However, it is difficult to maintain the hierarchical structure for routing due to node movement. This paper proposes an adaptive method for maintaining the hierarchical structure. The features of the proposed method are (1) the roles of nodes for the hierarchical structure are changed depending on the status of nodes in the restricted vicinity, and (2) the cluster size is adjusted so that the number of nodes in each cluster is bounded by two constants. The adaptability of the proposed method has been evaluated by theoretical considerations and simulation experiments. The results show that node roles and clusters efficiently converges to stable states because of the features. The proposed method therefore has high adaptability to node movement.

MAT: an end-to-end mobile communication architecture with seamless IP handoff support for the next generation internet

The technological advancement in the area of handheld mobile devices has resulted in a movement towards total mobility. Real-time applications are demanding such a flexible mobility support that would not interact adversely with the existing protocols, especially with Quality of Service (QoS) and security mechanisms. We believe that this could be achieved by providing mobility services through the mobile nodes themselves rather than via proxies. This paper proposes an end-to-end mobile communication architecture, called Mobile IP with Address Translation (MAT). MAT does not require any modification in the core network. To realize mobility we use address translation within host-nodes at the IP layer. We describe MAT architecture and show its mobility capability by prototype implementation and evaluation. Preliminary results show that MAT is fully compatible and works fine in both IPv4 and IPv6 environment. We also compare its features with Mobile IPv4 (MIP), Mobile IPv6 (MIPv6) and Location Independent Network Architecture (LIN6) protocols. Furthermore we propose a handoff technique based on MAT which helps to reduce service disruption interval significantly.

Real-time camera control for videoconferencing over the Internet

In videoconferencing, which means a small group meeting, interactive distance learning and so on, there is a requirement to get required video at a remote site freely and easily by local control of a remote camera. However, there are some delays between camera control operations at a remote site and actual video images displayed on a local screen. Delays are caused by network delays between sender and receiver and by video compression delays. To operate a remote camera interactively, a user must control the device considering these delays. We describe these problems in the case of videoconferencing and develop a real time camera control system to solve them. Our approach does not involve reducing delays but showing delays for users by some indication under the current environment. With our proposed system, a user can easily operate a remote camera without considering network and compression delays. We use a new camera control protocol designed by us in our system. We also describe a prototype system and its evaluation used in distance learning.

A Mobility Management System for the Global Live Migration of Virtual Machine across Multiple Sites

With rapid spread of virtualization technologies, Live migration which provides the ability to migrate a running virtual machine (VM) among physical hosts without interruption. Especially, Global Live Migration (GLM) which enables to migrate VM across the geographically-distributed Wide Area Networks (WANs) is an essential step towards development of the inter-cloud environment. However, GLM gets a bit complicated for network configuration compared with ordinary live migration. We have already proposed the GLM method which implements IP mobility support architecture with multiple interfaces to enable live migration among distributed sites consisting of different IP network segments. However, there is no sufficient consideration about the management of smooth handoff for the VM migration on the Internet. In this paper, we propose a mobility management system for GLM, and integrate into our developed nation-wide virtualization infrastructure. The proposed system enables VMs seamless handoff without any modification of the hypervisor while keeping network configuration of the migrating site. Performance evaluation shows the processing overhead of the proposed management system with GLM among multiple sites which are more than 600 km distant. As a result, we confirm that the proposed system provides smooth handoff for the VM on the widely-distributed environment if the proposed system is implemented.

Realizing high mobility through an end-to-end network architecture with IP diversity support for real time Internet applications

This paper presents a mobile-controlled handoff with an end-to-end communication architecture that helps to provide high mobility without requiring any special service from the visiting networks. The handoff utilizes the IP diversity created by dual network interfaces at the mobile node and exploits the overlapping area between subnets. The end-to-end network architecture is particularly suitable for low bit rate delay sensitive real time applications, where payload tends to be short and packet header overhead is particularly significant. We describe the network architecture and show the mobility support by prototype implementation and its performance evaluation. We also develop an analytical model of handoff and compare the performance of handoff in proposed network architecture and mobile IPv6. Performance evaluation shows that the handoff quality not only depends on the location but also on the implementation design of the location database servers. We see significant latency improvement due to our implementation as compare to mobile IPv6.

Vertical Handover Control Considering End-to-End Communication Quality in IP Mobility

In this paper, we propose a vertical handover decision system for IP mobility communication and describe its implementation with existing IP mobility architecture. Our proposed handover decision tries to reflect that a specified communication quality such as VoIP takes a priority. In other words, the purpose of our proposal is to prefer the specified communication quality in handover across heterogeneous networks. To realize this, the proposed decision method decides handover by a given user policy that a specified communication has priority and by end-to-end network performance. These handover criteria are measured between a mobile node and its correspondent node in IP mobility communication. In evaluations by experiments with the prototype system, we show that the proposal improves end-to-end communication quality in the viewpoint of QoS class classified by ITU-T Y.1541 compared the existing decision methods. Also, we mention the difficulty of deployment of this system.

Digital Signage with Audience Detection Using TV Broadcasting Waves

We propose of a digital signage system with a new audience detection system using TV broadcasting waves and show its experimental trial at our university for about three months. For audience motion detection, we use received level fluctuations of TV broadcasting waves by sensing physical movement. The authors have already developed this detection technique and we applied this as audience detection of digital signage. When our detection method detects human motion, a digital signage system will turned on its display. This flow grabs more attention to the signage display and effectiveness of saving electric power. Through the experimental trial, we show that our detection method provides effectiveness for audience detection of digital signage with a big monitor and we can save the electric power of 60-70% of the signage display and one of 94% in business days and in holidays, respectively.

A Handover Control of Mobile Nodes with IP Mobility in Heterogeneous Wireless Networks

Assuming all-IP wireless networks in the next generation, seamless vertical handover mechanism in IP mobility satisfying QoS requirements for variety such as user policies, dynamic network status, and a device type of a mobile node is required. In this paper, we propose a handover control mechanism coordinated with IP mobility architecture and design it as a middleware which works in a mobile node independently from IP mobility architecture. The prototype system integrates dynamic information of geographic location of the mobile node and its link layer information. It also decides the suitable network interface from them and gives its decision result to IP mobility architecture. We installed this software in a mobile client of a content delivery system for tourism and demonstrated it at Peace Memorial Park in Hiroshima as a field trial. Through this trial, we verified the functions of the developed software and discussed the problems as a middleware solution.

Development of a topology controllable testing environment for mobile ad hoc network software

A mobile ad hoc network is an autonomous wireless network which consists of mobile nodes without any base stations. Many routing schemes and services have been proposed for mobile ad hoc networks. However, since these schemes tend to be evaluated through simulation experiments, it is not known whether they work effectively in real environments or not. Therefore, in order to verify their practical use in mobile ad hoc networks, it is necessary to perform field experiments using actual mobile nodes. If the network size is large, it is difficult to perform field experiments due to problems with limited battery, difficulty of topology control and so on. Realization of rapid topology change of the ad hoc networks topology is especially difficult. In order to solve this problem, this paper proposes a testing environment for mobile ad hoc network software, which emulates field experiments in wired networks.