Catálogo de publicaciones - libros

The Optimized Link State Routing is one of the most important algorithms supporting the Mobile Ad Hoc Networks technology. The work hereby portrayed aims, therefore, to supply an administration structure for such protocol. The two framework components and the offered entities are a Management Information Base and a derived SNMP subagent implementation.

The study of mobile ad hoc networks depends on understanding protocols from simulations, before applying on a real world setting. To produce a real-world environment within which an ad hoc network can be formed among a set of nodes, there is a need for the development of a realistic, generic and comprehensive mobility model instead of random-based models. Previously, realistic mobility models such as obstacle mobility and pathway mobility model, etc, has been proposed. In these mobility models, there are movement paths and obstacles that constrain the movements and signals of the nodes. In this paper, we propose a new Obstacle Mobility Model Based On Activity Area. In this model our focus is on the movement pattern of the nodes, first we constructed environment simulation that included predefined pathways and obstacles. Then, we consider several clusters each of which has a given geographic activity area, speed and capacity. The nodes become member of clusters. In our model similar to real world, each node belongs to a particular activity area that its existence probability, in this area, is more than other places. This paper shows that various MANET environments can be modeled based on this work. A sample environment is also simulated and the result is compared with the Obstacle Mobility and Random Waypoint model. The results show that movement pattern and speed of the nodes have a significant influence on the performance of MANET protocols.

Because embedded systems commonly have slow processor and small memory, embedded software must be more efficient and compact against the poor resource. In this paper, we suggest a tool to easily test embedded program’s performance and intuitively report the results with graphical views. The suggested tool is pure software without any additional hardware to test embedded software’s performance, so developers can save development cost and time. To improve the usability and the reusability for test scripts and testing results, we design XML-based DTDs for those. Through the graphical views, developers can intuitively analyze software’s test results and easily understand the meaning of the results. Developers can easily revise the test scripts to try to various testing their embedded softwares. We hope that the suggested tool will be useful for embedded-related software development. The test suite generator offers a test script wizard for users to easily make a test driver. The report generator converts a string-type result to an XML-based class instance in order to raise reusability for the result.

Recently, the workflow systems such as uFlow and FollowMe adopt workflow models to support context-aware services in ubiquitous computing environments. A service in the ubiquitous computing environments must be executed according to a user’s situation information, which is generated dynamically from sensors. However, the existing workflow systems use such workflow languages as uWDL, BPEL and XLANG, which are not yet enough to support context-aware services in ubiquitous computing environments. In this paper, we propose a new workflow language and a workflow system for context-aware workflow services in ubiquitous computing environments. With the suggested workflow language and the workflow system, a user can describe contexts into workflow as service transition conditions and can apply changes of user’s service demand or situation information into an on-going workflow without interrupting or deleting workflow service. In order to verify the efficiency of the suggested language and system, we design a workflow scenario for context-aware services with the language and simulate a process that the proposed system changes dynamically contexts described in a workflow against changes of user’s situation information.

Ubiquitous computing is more complex and dynamic than distributed computing and mobile computing because of its pervasiveness. This paper pre-sents a context infrastructure to provide the semantic interoperability of context in a ubiquitous computing environment. In addition, we explore the web ser-vices approach to support interaction interoperability between the components of the context infrastructure on heterogeneous platforms. First, we develop con-text ontology- Entity, contextType, and Value - for providing semantic interop-erability of context. Then, we suggest a context infrastructure using the web services for interaction interoperability. We also explain context reasoning and evaluate the performance of the context infrastructure.

The importance and usage of XML technologies increase with the explorative growth of Internet usage, heterogeneous computing platforms, and ubiquitous computing technologies. With the growth of XML usage, we need similarity detection method because it is a fundamental technology for efficient document management. In this paper, we introduce a similarity detection method that can check both semantic similarity and structural similarity between XML DTDs. For semantic checking, we adopt ontology technology, and we apply longest common string and longest nesting common string methods for structural checking. Our similarity detection method uses multi-tag sequences instead of traversing XML schema trees, so that it gets fast and reasonable results.

Relational algebra is one of the main topics covered in undergraduate computer science database courses. In this paper, we present a web-based tool designed to automatically correct relational algebra queries. The tool is integrated in a more general e-learning environment and is used to reinforce teaching and learning on introductory database courses. A teacher enters relational algebra problems into the system and it generates personalized workbooks with different relational algebra exercises for each student. Students solve these exercises using a specifically designed interface. They enter relational algebra expressions to solve the assigned queries and the system provides immediate feedback and, when there are errors, advise about how to correct them. Only a web browser is required to use the tool, which has been used in our university with very promising results.

Conventional Fourier analysis gives adequate information about the dynamic characteristics of the slider air bearing for the stationary cases. The intermittent contacts for the extremely narrow gap, however, generate nonlinear and nonstationary impulse signals. Time-frequency analysis is widely used to investigate the nonstationary signal. Several time-frequency analysis methods are compared for the slider vibration signal caused by the impact against an artificially induced scratch on the disk. The representative Wigner-Ville distribution may suffer from severe interferences by cross terms even though it gives good resolution both in time and frequency. The smoothing process improves the interference problem at the expense of resolution. In order to get better resolution and less interference, the reassignment method is employed. Among others the reassigned Gabor spectrogram shows the best resolution and readability with negligible interference.

This paper presents knowledge and standard of design automation system for drawing hemming die of bonnet. Since significantly expensive cost of Hemming die in automobile development, it is not proper for producing small quantity. In addition, Hemming die requires much time to the drawing. Therefore we build the automatic hemming design which for cost down and for design time decrement by 3D CAD /CAM software. This systematic design automation system will supports the cost reduction of the price of hemming die.

One of the main obstacles of high track density is the confined servo bandwidth due to the low resonant frequencies of the mechanical components. We study the dynamic characteristics of the actuator system with a thin cantilever beam-like structure by using the finite element analysis. We develop the finite element models of each components of the actuator system and analyze the dynamics of the overall actuator system. The frequency response analysis shows that the modes regarding to the pivot bearing dominate in the lateral response. The lateral and vertical responses at the dimple point are compared with those for the suspension model to study the dynamic characteristics of a coupled structure.