Catálogo de publicaciones - libros

In this paper, we propose a Web Service framework for four kinds of geo-spatial services of GIS, SIIS, ITS, and GNSS. First, we examine what requirements are needed when designing the framework for various kinds of geo-spatial services. Then, we show how the framework can contribute to efficient geo-spatial services on both wired and wireless environment. Main issues in a design of the framework are to define interoperable interfaces, to define standardized metadata, and to design efficient geo-spatial server for various kinds of geo-spatial services. The framework fundamentally adopts international standards such as WMS, WFS, WCS, and WRS announced by OGC. The adoption satisfies the interoperability, extensibility, and standardization of the framework. Especially, we focus on a design of main memory-based GIS server(MM server). The MM server can efficiently serve huge volume of GML documents via Web Service. And experimental results show the effectiveness of the framework and MM server.

Regional web search engines provide users with spatially restricted web contents. We propose a time-specific regional web search engine, where users can retrieve both spatially and temporally restricted information from the Web, i.e. a description of a shop available at certain time in a certain region. Because there are many web pages containing descriptions of more than one geographic entity, a matching mechanism of spatial and temporal attributes is required. We used HTML tag structures to make matches between addresses and temporal interval expressions. Based on the extracted result, map-based visual interface was implemented.

The results of location-dependent queries(LDQ) generally depend on the current locations of query issuers. Many mechanisms, such as broadcast scheme, prefetching scheme, or caching scheme have been developed to improve system performance and provide better service for location dependent information services(LDISs). However, the client’s mobility may lead to inconsistency problems. In this paper, we introduce the broadcast-based LDIS scheme(BBS) in the mobile computing environment. In the BBS, broadcasting data items are sorted sequentially based on their location and the server broadcasts the location dependent data(LDD) without additional indices. Then we present a data prefetching scheme and OBC(Object Boundary Circle) in order to reduce the client’s tuning time. The performance for the proposed scheme is investigated by various environmental variables such as distributions of the data items, average speeds of the clients and the size of the service area.

A large amount of data including HTML documents and Internet mails has been distributed over the Internet. Most of the data on the Internet include geo-referenced descriptions. We have studied a method of converting such descriptions like addresses into their corresponding coordinates, that is, tuples of longitude and latitude. The process of converting descriptions into coordinates is called geocoding. In this paper, we focus on natural route descriptions as a new type of target to geocode. We first explain a core schema of sidewalk network databases on the basis of a characteristic of natural route descriptions, and then propose Formal Route Statement (FRS) to represent and process natural route descriptions by means of a computer. Also, we present our prototype system to geocode natural route descriptions using sidewalk network databases based on our proposed framework.

Location-Based Service(LBS) is a wireless application service that uses geographic information to serve a mobile user. Recent research on the LBS focuses on context sensitive computing and visualization. Location is the core context in context sensitive LBS and the use of the map is the most efficient way to visualize the geographic information. Many existing researches, however, has limited capability to provide dynamic map services and realistic information acquired from the Web. The goals of our research are to fully access geographical information and incorporate it with the LBS services. For the purpose, it is important to extract semantically relevant geographical information from the Web and efficiently present it to mobile users. In this paper, we present an effective LBS approach based on advance Mobile GIS and Web technologies. We design and implement the prototype of the Tour Guide System as a motivating application of LBS.

Mobile transactions for updating spatial data are long-lived transactions that update local copies of the mobile platforms on disconnection. Since a mobile transaction is physically separated from its global transaction, the concurrent updates of mobile transactions should be merged into the global database after committing. Validation-based schemes, which are well-known to be appropriate for mobile transactions, have the overhead of aborting long duration transactions that conflict with some transactions. It is definitely unacceptable to cancel all the updates of a long-lived transaction due to conflicts with just a few objects. This paper introduces a novel reprocessing-transaction model that handles update conflicts between mobile transactions without aborting. Instead of aborting mobile transactions that conflict with committed transactions, the proposed model executes a new subtransaction called , which reexecutes exactly the conflicted operations on conflicted objects with foreign conflicted objects. Foreign conflicted objects are part of the data committed by the other concurrent transactions and are related to the conflicted objects. We also propose to allow the non-conflicted objects of a mobile transaction to be incrementally exposed to other concurrent transactions in order to reduce the starvation of reprocessing transactions. Our reprocessing transaction model has the benefit of being able to serialize mobile transactions without aborting or waiting.

Interoperating Geographic Information Systems (GIS) poses several challenges. First, despite OpenGIS Consortium recommendations, GML is an emerging standard. Second, each GIS provides its own proprietary format as well as its specific query language; while geographic resources are designed for a variety of different purposes. Finally, orthogonal directions in the design of geographic resources may affect the semantics of the data they contain and impair their integration.

With the proliferation of GIS data and resources over the Internet, there is an increasing demand for robust geospatial information services that allow federation/interoperation of massive repositories of heterogeneous spatial data and metadata.

The purpose of this paper is to show how – a data integration technique – can help in building such a Web-based required geospatial service. This technique has been fully implemented in the context of a geographic mediation/wrapper system that provides an integrated view of the data together with a spatial query language. As a proof of concept, we deployed the service in building a prototype for an interoperability application involving several catalogues of satellite images.

Geographic information systems (GIS) are becoming more usual due to the improved performance of computer systems. GIS applications are being developed using the three-tier software architecture traditionally used for general-purpose information systems. Even though this architecture is suitable for GIS applications, the special nature and exclusive characteristics of geographic information pose special functional requirements on the architecture in terms of conceptual and logical models, data structures, access methods, analysis techniques, or visualization procedures.

In this paper, we propose a generic architecture for GIS that provides support for the special nature of geographic information and conforms with the specifications proposed by the ISO/TC 211 and the OGC. Our strategy to achieve this goal consists of two steps: (i) we analyze the special characteristics of GIS with respect to traditional information systems, (ii) and we adapt the traditional three-tier architecture for information systems to take into account the special characteristics of GIS.

Finally, we have tried to apply the architecture that we propose in the development of a complete and complex real-life GIS application using commercial tools in the analysis, design and implementation. We describe this application, and we use it to describe the limitations of current commercial GIS development tools by analyzing the differences in the architecture of the resulting system with respect to our proposal.

Web servers which provide Geographical Information System (GIS) services are very vulnerable against attacks exploiting web-based programming errors. A traditional Intrusion Detection System (IDS), however, has limitations to detect web-based attacks because they usually use signature-based IDS. Therefore, we propose IDS based on Hidden Markov Model (HMM) for securing GIS web servers. We adopt HMM which has been achieved good performance in pattern recognition and intrusion detection. We demonstrate effectiveness and efficiency of our proposed system by carrying out several experiments.

With the emergence of an infrastructure for location-aware mobile services, the processing of advanced, location-based queries that are expected to underlie such services is gaining in relevance. While much work has assumed that users move in Euclidean space, this paper assumes that movement is constrained to a road network and that points of interest can be reached via the network. More specifically, the paper assumes that the queries are issued by users moving along routes towards destinations. The paper defines in-route nearest-neighbor skyline queries in this setting and considers their efficient computation. The queries take into account several spatial preferences, and they intuitively return a set of most interesting results for each result returned by the corresponding non-skyline queries. The paper also covers a performance study of the proposed techniques based on real point-of-interest and road network data.