Yunmook Nah

Design of Location-Based Web Service Framework for Context-Aware Applications in Ubiquitous Environments

Recently, smart spaces are being created using RFID or USN technologies in ubiquitous computing environments, and the number of researches and applications related with context-aware systems, which process sensed data collected from numerous sensors and provide automated services properly according to situations, are ever increasing. There are also sharp increase in demands and needs for location-based services using location information, due to the development of wireless internet and mobile systems. This paper proposes a system which allows the users to access desired services by interacting with service providers at any place in various smart spaces using mobile devices such as smart phones. We propose the Location-based Context-Aware Web Service Framework, so called LOCA Framework, by applying SOA model as a way of satisfying these requirements.

A Cluster-Based TMO-Structured Scalable Approach for Location Information Systems

Location-based service (LBS) systems have recently become a subject of active research and development. A key issue in such systems is efficient management of current and past location information of moving items. In the past two years, we have been establishing a new LBS system architecture, named the GALIS (Gracefully Aging Location Information System), which is based on the new approach of using a cluster of database server nodes and effecting efficient distributed and parallel computing in both real-time update of location records of moving items and processing of location-related queries. Each server node is dedicated to keeping records relevant to a different geographical zone and a different temporal zone. Each subsystem in GALIS is structured as a TMO network for the sake of easy analysis and expansion. A prototype implementation of GALIS has been realized only partially, and its full implementation is under way. In this paper, major features of GALIS are presented together with discussions on trade-off considerations which led to the adoption of those features. Issues remaining for further research are also briefly discussed.

Intelligent web image retrieval system

Recently, the web sites such as e-business sites and shopping mall sites deal with lots of image information. To find a specific image from these image sources, we usually use web search engines or image database engines which rely on keyword only retrievals or color based retrievals with limited search capabilities. This paper presents an intelligent web image retrieval system. We propose the system architecture, the texture and color based image classification and indexing techniques, and representation schemes of user usage patterns. The query can be given by providing keywords, by selecting one or more sample texture patterns, by assigning color values within positional color blocks, or by combining some or all of these factors. The system keeps track of users preferences by generating user query logs and automatically add more search information to subsequent user queries. To show the usefulness of the proposed system, some experimental results showing recall and precision are also explained.

Distributed scalable location data management system based on the GALIS architecture

A challenging task in the LBS system engineering is to implement a highly scalable system architecture which can manage moderate-size configurations handling thousands of moving items as well as upper-end configurations handling millions of moving items. The architecture named the GALIS is a cluster-based distributed computing system architecture that consists of multiple data processors, each dedicated to keeping records relevant to a different geographical zone and a different time zone. In this paper, we explain a prototype location data management system structuring major components of GALIS by employing the TMO programming scheme, including the execution engine middleware developed to support real-time distributed object programming and real-time distributed computing system design. We present how to generate realistic location sensing reports and how to process such location reports and location-related queries. Some experimental results showing performance factors regarding distributed query processing are also explained.

TMO-structured cluster-based real-time management of location data on massive volume of moving items

A major challenge in the field of location based service (LBS) system engineering, is to establish a highly scalable system architecture which can be instantiated in moderate-size configurations handling thousands of moving items as well as in upper-end configurations handling millions of moving items. We are exploring an approach of using a cluster of database server nodes and effecting efficient distributed and parallel computing in both real-time update of location records of moving items and processing of location-related queries. The approach of developing efficient middleware which is layered on a cluster of nodes running commercial off-the-shelf database servers, has been adopted. The middleware design is substantially based on the TMO scheme for real-time distributed object programming and real-time distributed computing system design, which enables low-overhead coordination of distributed computations and highly abstract distributed programming styles.

Long-term location data management for distributed moving object databases

To handle the extreme situation that must manage positional information of a very large volume, at least millions, of moving objects, a cluster-based scalable distributed computing system architecture, called the GALIS, which consists of multiple data processors, each dedicated to keeping records relevant to a different geographical zone and a different time zone, was proposed. In this paper, we propose a valid time management and time-zone shifting scheme, which are essential in realizing the long-term location data subsystem of GALIS, but missed in our previous prototype development. We explain how to manage valid time of moving objects to avoid ambiguity of location information. We also describe time-zone shifting algorithm, with three variations, such as RT-TZS, B-TZS and TPB-TZS. Through experiments related with query processing time and CPU utilization, we show the efficiency of the proposed time-zone shifting schemes

Measuring similarity of windows applications using static and dynamic birthmarks

A software birthmark is unique, as certain native characteristics of a program, hence can be used to measure the similarity between programs. In general, a static software birthmark does not need program execution, but is more vulnerable to attacks by semantic-preserving transformations. A dynamic software birthmark is applicable to packed executables, but cannot cover all the possible program paths. In this paper, we propose a novel effective technique to measure the similarity of Microsoft Windows applications using both static and dynamic birthmarks, which are based on the list of system APIs as well as the frequency of system API calls. Because system APIs are located in Windows system directories and act as a bridge between applications and the operating system, our birthmarks are resilient to obfuscations and compiler optimizations. A static birthmark consists of the system API call frequency of a target program, which can be extracted by scanning the executable file. A dynamic birthmark is the frequency of system API function calls, which can be extracted by a binary instrumentation tool during the execution of the program. To evaluate the effectiveness of the proposed technique, we compare various types of Windows applications using both the static and dynamic birthmarks. To demonstrate the robustness, we compare packed executables that were compressed by a binary packing tool. We carry out additional experiments for measuring the similarity between target Windows applications at the source code level and verify the evaluation results. The experimental results show that our birthmarks can effectively measure the similarity between Windows applications, as intended.

An intelligent image retrieval system using XML

With the rapid development of Internet technology, the number of Internet users and the amount of multimedia information on the Internet is ever increasing. Recently, the Web sites, such as e-business sites and shopping mall sites, deal with lots of image information. As a result, it is required to support content-based image retrieval efficiently on such image data. This paper proposes an intelligent image retrieval system, which adopts XML technology. To support object-based content retrieval on product catalog images containing multiple objects, we describe a multilevel metadata structure representing the local features, global features, and semantics of image data. To enable semantic-based and content-based retrieval on such image data, we design an XML-schema for the proposed metadata. We also describe how to automatically transform the retrieval results into the forms suitable for the various user environments, such as Web browser or mobile browser, using XSLT. The proposed scheme can be utilized to enable efficient image metadata sharing between systems, and it will contribute in improving the retrieval correctness and the users satisfaction on content-based e-catalog image retrieval.

A color-ratio-based image retrieval for e-catalog image databases

Most of the content-based image retrieval systems are based on RGB color space. Using the average amount of red, green, and blue is appropriate for natural images. But, for the case of e-catalog images, the number of colors for a given catalog image is only a few and the average color of an image is meaningless to customers. This paper presents a color comparison scheme based on the HSI color ratio to improve the accuracy of retrieval on e-catalog images. We have divided hue by 30 degrees, resulting in 12 colors. By considering saturation and intensity, and eliminating some duplicate combinations, we further divided each hue into 15 categories, thus resulting in 186 representative colors which is quite smaller than 1.7 million colors of 24 bit RGB case. The resulting 186-element HSI histogram is represented using presence bitmap vector(186 bit) and ratio vector(93 bytes). For the e-catalog images, most of the presence vector bits are 0 since there are only a few colors. We have implemented the prototype retrieval system and showed the usefulness of the proposed system by comparing measures such as precision and search speed with RGB histogram based schemes.

TMO-structured distributed location information system prototype

To realize location-based services, it is essential to handle the extreme situation that must cope with a very large volume, at least millions, of moving items. In this paper, we describe a location information system prototype of GALIS, which is a cluster-based scalable distributed computing system architecture which consists of multiple data processors, each dedicated to keeping records relevant to a different geographical zone and a different time zone. The proposed system contains all of the major computing nodes of GALIS architecture and is developed as a middleware on top of commercial main-memory database engines and spatial database engines, for short-term data and long-term data processing, respectively. To show the usefulness of our system, some experimental results showing clear advantages of distributed computing are also explained.