• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.11
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• pp.2062-2068
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• 2008

In a u-City project in Busan, public transportation which is one of ITS has been considered. RFID system embedded with PXA255 chip and middleware capable of communicating a server side was developed. To perform data communication link with traffic card, developed system consists of wireless modules that are wireless LAN (IEEE802.11a/b and IEEE802.16. Using developed RFID system and middleware, it is expected that this system becomes a basic infrastructure to support a service of u-Traffic for u-City construction.

• Journal of KIISE:Databases
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• v.33 no.6
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• pp.578-589
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• 2006

Owing to the proliferation of Radio Frequency Identification (RFID) technologies which is being watched as a core technology of ubiquitous computing, applications which offer convenience to people using RFID technologies are more and more increased. To easily develop these applications, a middleware system which acts as a bridge between RFID hardware and application is essential. In this paper, we propose a novel XML-based RFID middleware system called UbiCore (Ubiquitous Core). UbiCore has following features: First, UbiCore employs its own query language called XQueryStream (XQuery for Stream Data) which is originated from XQuery. Second, UbiCore has the preprocessing phase called pre-filtering prior to query evaluation and reuses the intermediate result of previous evaluation to speed up the processing of RFID tag data stream. Third, UbiCore supports query on both continuously generated stream data and archived historical data. And last, UbiCore offers a distinct markup language called Context-driven Service Markup Language (CSML) to easily specify the linking information between context and service.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.4
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• pp.1-12
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• 2009

An RFID application needs to collect product's information scattered over the RFID network efficiently according to the globalization of RFID applied enterprises. To be informed of the stock status of products promptly in the supply chain network, especially, it is necessary to support queries that retrieve statistical information of tagged products. Since existing RFID network does not provide these kinds of queries, however, an application should request a query to several RFID middleware systems and analyze collected data directly. This process makes an application do a heavy computation for retrieving statistical information. To solve this problem, we define a new Distributed Continuous Query that finds information of tagged products from the global RFID network and provides statistical information to RFID applications. We also propose a Distributed Continuous Query System to process the distributed continuous query efficiently. To find out the movement of products via multiple RFID systems in real time, our proposed system uses Pedigree which represents trade information of items. Our system can also reduce the cost of query processing for removing duplicated data from multiple middleware systems by using Pedigree.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1639-1646
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• 2008

This study designed and realized a new type of RFID middle-ware based on .NET Compact Framework platform using PXA255 embedded board and Windows CE as operating system. The proposed embedded RFID middle-ware system controls via LAN a number of RFID sensors using RS-232 as interface and was designed on the basis of components of each function necessary RFID middle-ware. Application module operating in the SOA environment analyzes the data received from the RFID sensors with the embedded RFID middle-ware and in turn performs appropriate business logic. Client module to be used by end users can use RFID information in database, by web method call of application.

• The KIPS Transactions:PartD
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• v.15D no.1
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• pp.73-86
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• 2008

Because of its capability of automatic identification of objects, RFID(Radio Frequency Identification) technologies have extended their application areas to logistics, healthcare, and food management system. Load balancing is a basic technique for improving scalability of systems by moving loads of overloaded middlewares to under loaded ones. Adaptive load balancing has been known to be effective for distributed systems of a large load variance under unpredictable situations. There are needs for applying load balancing to RFID middlewares because they must efficiently treat vast numbers of RFID tags which are collected from multiple RFID readers. Because there can be a large amount of variance in loads of RFID middlewares which are difficult to predict, it is desirable to consider adaptive load balancing approach for RFID middlewares, which can dynamically choose a proper load balancing strategy depending on the current load. This paper proposes an adaptive load balancing approach for RFID middlewares and presents its design and implementation. First we decide a performance model by a experiment with a real RFID middleware. Then, a set of proper load balancing strategies for high/medium/low system loads is determined from a simulation of various load balancing strategies based on the performance model.

• 한국디지털정책학회:학술대회논문집
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• 2006.12a
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• pp.397-407
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• 2006

• Journal of Korea Spatial Information System Society
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• v.8 no.1 s.16
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• pp.1-16
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• 2006

Recently, human based computing environment for supporting users to concentrate only user task without sensing other changes from users is being progressively researched and developed. But middleware deletes steream data processed for reducing process load of massive information from RFID sensor in this computing. So, this kind of middleware have problems when user demands probability or statistics needed for data warehousing or data mining and when user demands very important stream data repeatedly but already discarded in the middleware every former time. In this paper, we designs Sensor Middleware Architecture on Multi Level Spatial DBMS with Snapshot and manage repeatedly required stream datas to solve reusing problems of historical stream data in current middleware. This system uses disk databse that manages historical stream datas filtered in middleware for requiring services using historical stream information as data mining or data warehousing from user, and uses memory database that mamages highly reuseable data as a snapshot when stream data storaged in disk database has high reuse frequency from user. For the more, this system processes memory database management policy in a cycle to maintain high reusement and rapid service for users. Our paper system solves problems of repeated requirement of stream datas, or a policy decision service using historical stream data of current middleware. Also offers variant and rapid data services maintaining high data reusement of main memory snapshot datas.

• The Journal of the Korea institute of electronic communication sciences
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• v.4 no.2
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• pp.101-107
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• 2009

Modern society encounters various accidents due to industrialization and numbers of studies are going on to minimize damage from accidents. For prevention of accidents, it is necessary to design a system that helps making accurate judgment in emergency cases and is able to instantly manage each contingency. Various studies are currently going on contingency information system under ubiquitous environment. However, there have not been sufficient studies on the system that is able to monitor and process multiple contingencies and thus we still have difficulties in coping with multiple contingencies promptly. This study designs a RFID/USN middleware system for multiple contingencies control that receives data from various kinds of sensors and saves data after time marking thus is able to provide conjectured context when requested.

• Journal of Information Management
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• v.39 no.2
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• pp.27-43
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• 2008

This paper analyzes feasibility studies regarding the structure, applications and issues of the library RFID system. In this study, the structure and principle, operation mode and middleware of library RFID system are reviewed in detail, Finally this paper analyzed and proposed the RFID applications that could be efficient to information management and user service of library and the major problems and improvements of library RFID system.

• The KIPS Transactions:PartD
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• v.14D no.3 s.113
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• pp.273-284
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• 2007

RFID middleware systems collect and filter the RFID streaming data gathered continuously by numerous readers in order to process requests from applications. These requests are called continuous queries because they are kept on executing during certain periods. To enhance the performance of the middleware, it is required to build an index to process the continuous queries efficiently. Several approaches of building an index on not data records but queries, called Query Index, are proposed and widely used for evaluating continuous queries over streaming data. The EPCglobal proposed an Event Cycle Specification (ECSpec) model, which is a standard query interface for RFID applications. Continuous queries based on ECSpec consist of a large number of segments for representing the query conditions. The problem with using any of the existing query indexes on these continuous queries is that it takes a long time to build the index because it is necessary to insert a large number of segments into the index. To solve this problem, we propose an Aggregate Transformation that converts a group of segments into a compressed data which is representative of the segments. We compare the performance of a transformed index with the existing query indexes.