Catálogo de publicaciones - libros

Microkernels and virtual machine monitors are both utilized as platforms for running operating systems. Although there are many similarities in their designs and features, they have opposite advantages and drawbacks. A microkernel based system is highly portable. However, the interface it exposes is inflexible and incompatible with other real hardware interfaces. In contrast, a virtual machine monitor interface is identical to a specific real hardware interface. However, the implementation of virtual machine monitors highly depends on processor architectures and specific hardwares.

In this paper, we present a new model of virtual machine monitor, a flexible dynamic translator constructed on a portable microkernel. Our model offers both high portability and compatibility. Moreover, its flexible interface could be reconfigured to support various types of hardware interfaces. The results of the evaluation show that the performance of our prototype system is unsatisfactory, so we propose some techniques to improve its performance as future work.

These days, embedded and ubiquitous devices are becoming feature rich, and multiprocessor architectures for those devices are on the horizon. In order to utilize the resources of multiprocessor systems efficiently and securely, virtual machine monitors (VMMs) have been common among servers and desktop systems. The same can be applied if the cost of virtualization becomes much less expensive. In this paper, we introduce , a new lightweight virtualization technique. Mesovirtualization makes VMMs smaller and requires only a few modifications for the guest operating system (OS) source code. We designed and implemented a VMM named Gandalf according to mesovirtualization. Our experimental results show that Linux on Gandalf performs better than XenLinux. Therefore, mesovirtualization makes virtualization environments suitable for embedded and ubiquitous devices.

A new customizable user interface for smart devices based on hyperlink associability is presented. Although mobile devices should be easy to use, many current devices have complex and widely varying interfaces. The proposed framework, Hyrax, attempts to improve the menu structure and accessibility of functions while considering user preferences. In Hyrax, the user interface is constructed and customized using hyperlinks for access to application functions. We focus herein on the user interface of a phone and present the customizable menu structure of the phone using XLink defined in W3C and the External Function Interface (EFI) defined in the WAP Forum specifications. To implement the proposed framework, we have developed a design tool to customize the user interface with hyperlinks and a runtime environment, which manages the objects generated by the tool with the hyperlinks, to evaluate the framework.

In moving object databases, researches on the spatio-temporal access method are very important for the efficient search of moving object location in ITS, LBS, and Telematics. Recently, researches are being made actively on the efficient management of the current location of moving objects and on the estimation of future location using information such as the current location and moving pattern of moving objects. In this paper, we propose Map-Based R-tree(MBR-tree), which is a new current location index structure for indexing the current location of moving objects in an urban area, a 2-dimentional space. MBR-tree is an index which forms the MBR(Minimum Bounding Rectangle) of R-tree nodes using static objects(or fixed objects) on the map. Because moving objects generally moves within a static object, if the MBR is formed using static objects, we can reduce the cost of updating the index of the current location of moving objects. In addition, it shows superior performance in semantic search that searches in a specific building or place (e.g. “Who are in Konkuk university?”) rather than in an arbitrary area. Finally, to test the index proposed in this paper, we compared its performance with that of hashing technique and Lazy Update R-tree using various datasets and proved the superiority of its performance.

The development of applications in the domain of Ubiquitous Computing has to deal with some unique challenges. The target environment consists of very heterogeneous and partly low-power devices. It changes rapidly due to wireless communication and mobile users. We propose to use model-driven development based on Abstract State Machines to deal with these challenges. Applications are defined on high levels of abstraction and efficient implementations tailored to the target platform are automatically generated.

As pervasive computing permeate into user’s lives, many embedded devices based on Linux exist around the users. In this circumstance, the heterogeneousness of operating systems causes incompatibility problems in sharing peripherals since the users and the devices have a different operating system. In this paper, we propose a USB Cross-platform Extension to share peripherals in a heterogeneous environment via a TCP/IP network. Using our approach, the users can access remote peripherals with different operating systems as if they were attached to a local computer. According to our evaluation results, our approach has some overhead, but sufficient performance for practical usage.

In the literature there exist many proposed architectures for sensor fusion applications. This paper briefly reviews some of the most common approaches, i.e the JDL fusion architecture, the Waterfall model, the Intelligence cycle, the Boyd loop, the LAAS architecture, the Omnibus model, Mr. Fusion, the DFuse framework, and the Time-Triggered Sensor Fusion Model, and categorizes them into abstract models, generic and rigid architectures. While an abstract model does not guide the designer in the concrete implementation, the generic architectures provide a generic design but leave open several design decisions regarding operating system, hardware, communication system, or database system. Rigid architectures specify at least some of these aspects and therefore provide existing hardware designs, tools, and source code at the cost of flexibility.