Toshihiro Takada

t-Room: Next Generation Video Communication System

In this paper, we present t-Room, the next generation video communication system we are developing. Our approach is to build rooms with identical layouts, including walls of display panels on which users and physical or virtual objects are all shown at life-size. In this way, the user space enclosed by t-Rooms surrounding displays can be shared as a common space at any other site. In other words, the enclosed spaces overlap each other. This configuration effectively provides symmetric reproduction of the audio-visual information surrounding local and remote users and objects. The feeling provided by t-Room is different from that by conventional videoconferencing systems, since there is no spatial barrier separating users such as the video screen of a conventional videoconferencing system. Furthermore, t-Room benefits in every way from Next Generation Network (NGN) technology: QoS, service productivity, and security. We view t-Room as a future form of telephone service.

Dynamic multimedia integration with the WWW

This paper presents a novel framework for seamlessly integrating continuous media, such as audio and video, with the World Wide Web (WWW). Continuous Media with the Web (Cmew) enhances the interactivity of continuous media by associating hyperlinks with spatial-temporal parts of the media. The scenario control architecture in Cmew provides flexible and dynamic control over continuous media in multimedia documents. The Cmew media player has been implemented as a Java applet, which enables its use in the current WWW environment.

Reusing Coordination and Negotiation Strategies in Multi-Agent Systems for Ubiquitous Network Environment

Recently, we proposed an intelligent ubiquitous computing (ubicomp) environment where sensors and/or their stations/servers have CPUs to cooperatively learn generalized series of sensed events that are involved in human activities. This can be regarded as a multi-agent application. Because ubicomp applications target support for daily-life activities, one of their characteristics is that the same/similar series of events occurs frequently. Multi-agent plans in applications of this type are used to foresee human activities and generate programs to assist them. Therefore, the same planning processes for conflict detection and resolution recur. This paper proposes a learning method in which past plans are exploited for problem solving in an environment where the same/similar problems appear repeatedly. We discuss how the plan is stored and reused using as an example the exploration of conflict-free routes in a room and then describe experimental results.

Effective Planning for Conflicting Situations for Ubiquitous Sensor Network Environments

Applications of sensor networks and ubiquitous computing have received attention. They can provide many kinds of important services for supporting daily and social activities in home, schools, offices and public spaces in the future (Kurihara, 2008). However, to realize these kinds of applications, a number of new technologies in AI and multi-agent systems (MAS) are also required because many devices and control programs are concurrently work to achieve their goals in cooperation with other ones. These works arise according to the human requirements based on their individual activities. In order to achieve these required goals, each agent has to create the plan (means-end analysis) and then performs it. However, the plan often conflict with those that are being created, already being scheduled, and executed by other agents because of the limited resources. Furthermore, since the human’s activities are usually real-time with deadline, the agent must also be able to complete its planning and resolution of these conflicts within a reasonable time to have an acceptable quality plan. This means that both efficient planning and sophisticated conflict resolution are strongly required. We adopt hierarchical planning (for example, see (Erol & Nau, 1994; Sacerdoti, 1974) using the decision-theoretic planning approach (Goldwin, & Simmons, 1998) for efficient planning but it is not trivial to apply hierarchical planning to MAS. In hierarchical planning, appropriate (abstract) plans are selected level by level to maximize the utility U(p), where p is the expected final plan comprising a sequence of primitive actions. However, in the MAS context, conflicts between agents affect the efficiency and quality of resulting plans. When a conflict is found at lower levels, an additional sophisticated process for avoiding it (conflict resolution) must be invoked and some extra actions (such as waiting for synchronization and detouring) may have to be added to the plan. The conflict resolution process may become costly or fail. Even a single conflict, if it is difficult to resolve, will result in a plan with 5

Implementation of flexible-playtime video skimming

In this paper, we propose a new time-reduction method for video skimming in which the focus is on the overall playback time. While fast-forwarding is a natural way to check whether or not items are of interest, the sound is not synchronized with the images and the lack of comprehensible audio data means that we must work from the images alone. The focus in video summarization has been solely on video segmentation, i.e. building a structure that represents the parts and flow of meaning in the video. In our system, the user simply specifies the running time required for the summarized video. We describe the current state of our prototype system and its results in testing, which show how well it works.

How coherent environments support remote gestures

Previous studies have demonstrated the importance of providing users with a coherent environment across distant sites. To date, it remains unclear how such an environment affects peoples gestures and their comprehension. In this study, we investigate how a coherent environment across distant sites affects peoples hand gestures when collaborating on physical tasks. We present video-mediated technology that provides distant users with a coherent environment in which they can freely gesture toward remote objects by the unmediated representations of hands. Using this system, we examine the values of a coherent environment by comparing remote collaboration on physical tasks in a fractured setting versus a coherent setting. The results indicate that a coherent environment facilitates gesturing toward remote objects and their use improves task performance. The results further suggest that a coherent environment improves the sense of co-presence across distant sites and enables quick recovery from misunderstandings.

Conflict estimation of abstract plans for multiagent systems

In hierarchical planning, selecting a plan at an abstract level affects planning performance because an abstract plan restricts the scope of primitive plans. However, if all primitive plans under the selected abstract plan have difficult-to-resolve conflicts with the plans of other agents, the final plan after conflict resolution will be inefficient or of low quality. In this paper, we propose a conflict estimation method to generate quality plans efficiently for multiagent systems by appropriately selecting abstract plans in hierarchical planning. This method enables agents to learn which abstract plans are less likely to cause conflicts or which conflicts will be easy to resolve.

Effective Selection of Abstract Plans for Multi-Agent Systems

This paper proposes a situation-based conflict estimation method that efficiently generates quality plans for multi-agent systems (MAS) by appropriately selecting abstract plans in hierarchical planning (HP). In HP, selecting a plan at an abstract level affects planning performance because an abstract plan restricts the scope of concrete-level (or primitive) plans and thus can reduce the planning cost. However, if all primitive plans under the selected abstract plan have serious and difficult-to-resolve conflicts with the plans of other agents, the final plan after conflict resolution will be inefficient or of low quality. This issue originates in the uncertainty of MAS, where other agents also have individual plans for their own goals and it is difficult to clearly anticipate which abstract plan will cause fewer conflicts with other agents’ plans. In the proposed method, by introducing conflict patterns that express the situations of conflicts among agents’ plans, agents learn and estimate which abstract plans are less likely to cause conflicts or which conflicts will be easy to resolve; thus, after conflict resolution, they can induce probabilistically higher-utility primitive plans. This paper also describes an experiment to evaluate our method. The results indicate that our method can improve the efficiency of plan execution.

An Implementation for Capturing Clickable Moving Objects

This paper discusses a method for identifying clickable objects/regions in still and moving images when they are being captured. A number of methods and languages have recently been proposed for adding point-and-click interactivity to objects in moving pictures as well as still images. When these pictures are displayed in Internet environments or broadcast on digital TV channels, users can follow links specified by URLs (e.g., for buying items online or getting detailed information about a particular item) by clicking on these objects. However, it is not easy to specify clickable areas of objects in a video because their position is liable to change from one frame to the next. To cope with this problem, our method allows content creators to capture moving (and still) images with information related to objects that appear in these images including the coordinates of the clickable areas of these objects in the captured images. This is achieved by capturing the images at various infrared wavelengths simultaneously. This is also applicable to multi-target motion capture.