Catálogo de publicaciones - libros

Multiplayer computer games are becoming more and more popular. While much effort has been contributed to point-to-point communication based architecture and network game traffic, we proposed a server decentralized game architecture based on Jabber in order to have high availability, performance, scalability, fault tolerance and security. Three components of the architecture: players, game servers and record-keeper are defined and functioned. The architecture is implemented and instanced as a Chinese Chess game. The game data are packed with XML stanzas and delivered to the addressed player through XML streams. In order to test the availability, the game is experimented and the result is meaningful even though the test environment is rough.

Wearable computers and other handheld devices are now used beyond the research lab, in diverse applications, and this trend toward ubiquitous computing is accelerating. One challenge that remains in this emerging research field is the ability to build reliable industrial information management and training system for the mobile knowledge workers in the manufacture application. A Wearable Learning and Support System which has been designed as tools to support learning, training and operation of maintenance activity in industrial settings is presented. With the context information service, resources information process, and adaptive strategies, this system can suit for the requirements of operation assistant, learning, training and information management processes on the job.

The ability to better understand role performing during the learning process of a collaborative learning team is very crucial, in order to effectively support online students. Leadership roles which have the most influence in directing the team should be carefully recognized. Identifying the emergent team leaders is challenging because these roles are normally distributed and shifted among team members over time. In this paper, a new approach for the leadership roles identification is, thus proposed. The collaboration patterns are examined with different points of social network views to discover the network locations of the leaders. The proposed leadership index is a combination of degree of centrality, closeness and betweenness. The experiment and the simulation results indicate that the proposed index is promising.

A model and a Java Framework to aid the construction of 3D Web-based Collaborative Virtual Environments (3D-CVE) are described in this paper. The proposal emphasizes on the interaction and collaboration among the entities (users’ avatars, agents, etc.) that populate the virtual world; and the services that they offer to each other in order to interact, or to carry out some kind of collaborative task. We propose a model for the conceptualization of CVE under the concept of social groups, a graph-based high level notation to specify the interactions among the entities that populate the CVE, and a Java based software framework that gives support to the model and the interaction graph in order to facilitate the implementation of the 3D-CVE. From the developing process point of view, the goal of the collaboration model and the framework proposed here is not only to develop 3D-CVE faster, but also the resulting 3D-CVEs have similar structures, they are easier to maintain and eventually to integrate. Design patterns were very useful to fulfill these characteristics, as we describe in the next sections. CVEs developed with the framework enable, through the Web browser, a shared understanding regarding many scientific, engineering and entertainment subjects concerned with three-dimensional data.

Wireless Local Area Network(WLAN) technology has been developed rapidly and impacted education greatly. Mobile learning(M-learning) is the trend of the modern education. The Mobile learning has a high requirement of multimedia applications on limited bandwidth network, but the transmission of voice and video becomes a bottleneck. Based on the polling scheme used in medium access control(MAC) protocols in IEEE 802.11 for WLAN, especially for delay sensitive multimedia information packet delivery, this paper focuses on improving the efficiency of polling scheme to satisfy the quality of service requirements. A new scheme model of polling system is analyzed and the information packet waiting time of voice and video is obtained. Through theoretic calculations and experiments based on voice and video traffic models it proves to be an efficient way of serving the M-learning.

A new freehand text entry method, called EasyStroke, is presented for mobile devices. Based on the multi-stroke philosophy and analogy principle, 26 lowercase characters are described. Trails of stylus movement are segmented dynamically and best approximated through the three captured points. Then, each segment is rendered immediately using hardware-accelerated OpenVG APIs. Finally, combination of the types of all segments flows into the small LUT-based recognizer, using some additional bits. Thus, this new method is easy, efficient and quick to use. Implementation and evaluation of such system are presented. Prototype of mobile game, WordCollection, is demonstrated to help users experience functions of both education and entertainment.

Anisotropic texture mapping is not suitable for mobile devices because of their limited power consumption and low performance. To solve this problem, this paper proposes a triangle-based sub-texel precision anisotropic filtering (TSPAF). Then a hybrid triangle-based sub-texel precision anisotropic filter (HTSPAF) is presented, which combines the bilinear filtering and TSPAF filtering with the MIPMap layer selection. The experimental results show that the new approach can obtain good quality images with lower hardware cost, which is thus feasible for mobile GPU hardware implementation.

Edutainment projects are by definition very “entertaining”, but in order to become implemented into the everyday teaching process they have to become something more and in some aspects also “something less” than an ordinary computer game. We report our experience with edutaining products we are authoring and their symbiosis with the electronic and paper textbooks as well as bringing modern education in concert with the classical experimental work e.g. in a biology class.

Virtual geographic environment is involved in many kinds of data, which are very huge. Many theories of 3D interactive visualization such as dynamic data loading are presented and applied to the navigation of the whole scene. However, in 3D modeling, some approaches such as segmentation of the whole scene into subareas are often adopted. Thus, the disaccord between visualization and modeling may cause trouble. In this paper, the integration of 3D interactive visualization and 3D modeling is discussed, and a collaborative 3D modeling environment is designed and constructed. As a case study, a virtual learning environment for Lushan fieldwork education is implemented.

We present a data-driven shape model for reconstructing human body models from one or more 2D photos. One of the key tasks in reconstructing the 3D model from image data is shape recovery, a task done until now in utterly geometric way, in the domain of human body modeling. In contrast, we adopt a data-driven, parameterized deformable model that is acquired from a collection of range scans of real human body. The key idea is to complement the image-based reconstruction method by leveraging the quality shape and statistic information accumulated from multiple shapes of range-scanned people. In the presence of ambiguity either from the noise or missing views, our technique has a bias towards representing as much as possible the previously acquired ‘knowledge’ on the shape geometry. Texture coordinates are then generated by projecting the modified deformable model onto the front and back images. Our technique has shown to reconstruct successfully human body models from minimum number images, even from a single image input.