• The KIPS Transactions:PartD
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• v.12D no.1 s.97
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• pp.43-50
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• 2005

The Processing domains of spatio-temporal databases are divided into time-series databases for moving objects and sequence databases for discrete historical objects. Recently the selectivity estimation techniques for query optimization in spatio-temporal databases have been studied, but focused on query optimization in time-series databases. There wat no previous work on the selectivity estimation techniques for sequence databates as well. Therefore, we construct T-Minskew histogram for query optimization In sequence databases and propose a selectivity estimation method using the T-Minskew histogram. Furthermore we propose an effective histogram maintenance technique for food performance of the histogram.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.10a
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• pp.100-105
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• 2008

EPCglobal은 기업 간의 물류 활동 촉진과 글로벌 유통물류 시스템 구축을 위하여 EPCglobal Architecture Framework을 제시 하였다. EPCglobal Architecture Framework의 한 구성 요소인 EPCIS(Electronic Product Code Information Services)는 EPC, 시간, 위치와 같은 물류 관련 정보에 대해 저장 및 검색 서비스를 제공한다. EPCIS는 단발성 질의(poll)와 연속 질의(subscribe) 검색 서비스를 제공한다. EPCIS의 연속 질의는 시스템 자동화 및 재고 관리, 공급망 관리를 위해 다양한 응용에서 활용이 가능하다. 일반적으로 연속 질의 처리를 위해서는 등록된 연속 질의와 입력된 데이터를 순차적으로 비교하는 Sequential Matching 기법을 사용한다. Sequential Matching기법은 등록된 연속 질의 수가 증가 할 경우 많은 부하를 발생 시키고, 이로 인해 시스템 처리 지연이 발생한다. 본 논문에서는 EPCIS의 시공간 EPC 데이터의 연속질의 처리 성능 향상을 위해 선택률 기반 효율적인 연속질의 처리 기법을 제안한다. 13차원의 도메인을 여러 개의 질의 색인으로 구성하고, 등록된 질의 정보를 기반으로 선택률을 계산한다. 선택률에 의해 변경되는 동적 질의 실행 계획을 제안함으로써, EPCIS에서 시공간 EPC 데이터의 연속질의 처리에 대해 평균 60%의 성능이 향상이 가능하도록 하였다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.3
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• pp.145-152
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• 2010

With the recent development of the ubiquitous computing technology, there are increasing interest and research in technologies such as sensors and RFID related to information recognition and location positioning in various ubiquitous fields. Especially, RTLS(Real-Time Locating Services) dealing with spatio-temporal data is emerging as a promising technology. For these reasons, the ISO/IEC published the RTLS standard specification for compatibility and interoperability in RTLS. Therefore, in this paper, we designed and implemented Spatio-temporal Query Processing Systems for efficiently managing and searching the incoming Spatio-temporal data stream of moving objects. Spatio-temporal Query Processing Systems's spatio-temporal middleware maintains interoperability among heterogeneous devices and guarantees data integrity in query processing through real time processing of unceasing spatio-temporal data streams and two way synchronization of spatio-temporal DBMSs. Web Server uses the SOAP(Simple Object Access Protocol) message between client and server for interoperability and translates client's SOAP message into CQL(Continuous Query Language) of the spatio-temporal middleware. Finally, this thesis proved the utility of the system by applying the spatio-temporal Query Processing Systems to a real-time Locating Services.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.1
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• pp.109-113
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• 2011

Recently, according to the development of ubiquitous computing, the u-GIS which not only used in u-Transport, u-Care, u-Fun, u-Green, u-Business, u-Government, and u-City but also used to provides various spatial information such as the location of user is being the core technology of the ubiquitous computing environment. In this paper, we implemented an mobile spatio-temporal Query Processing Systems for handling the Spatio-Temporal Data in mobile equipment.The mobile spatio-temporal Query Processing Systems provides the spatio-temporal data type and the spatio-temporal operator that is expanded by the spatial data type and the spatial operator from OepenGIS "Simple Feature Specification for SQL". It supports arithmetic coding compression techniques that is considered with a spatio-temporal data specific character. It also provides the function of data cashing for improving the importation and exportation of the spatio-temporal data between a embedded spatio-temporal DBMS and u-GIS server.

• The Journal of Society for e-Business Studies
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• v.15 no.3
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• pp.85-98
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• 2010

The prevailing infrastructure of ubiquitous computing paradigm on the one hand making significant development for integrating technology in the daily life but on the other hand raising concerns for privacy and confidentiality. This research presents a new privacy-preserving spatio-temporal query processing technique, in which location based services (LBS) can be serviced without revealing specific locations of private users. Existing location cloaking techniques are based on a grid-based structures such as a Quad-tree and a multi-layered grid. Grid-based approaches can suffer a deterioration of the quality in query results since they are based on pre-defined size of grids which cannot be adapted for variations of data distributions. Instead of using a grid, we propose a location-cloaking algorithm which uses the R-tree, a widely adopted spatio-temporal index structure. The proposed algorithm uses the MBRs of leaf nodes as the cloaked locations of users, since each leaf node guarantees having not less than a certain number of objects. Experimental results show the superiority of the proposed method.

• Journal of KIISE:Databases
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• v.27 no.1
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• pp.101-112
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• 2000

In Geographic Information System, spatial object can be changed in the attribute information, spatial location and the topological relation between them with the change of time. However traditional GIS deletes the old value of aspatial information and replaces them with new value. Therefore. it is difficult to manage thc history of changed spatial object and can not support the spatio-temporal queries including temporal queries. In this paper, we propose a spatio-temporal objected model to solve this problem. We implement the proposed model with spatio-temporal class using Gothic GIS tool. The historical information of an object is stored into the object itself for the effective history management. And, in order to provide the queries for the history of an object and spatio-temporal relationship, we add temporal operators, spatio-temporal operators, and spatio-temporal query operations into Gothic, and improve the facility of the Gothic.

• Spatial Information Research
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• v.20 no.3
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• pp.95-106
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• 2012

Recently, with increase and development of the wireless access network area, u-GIS Service is supported in various fields. Especially, spatio-temporal data is used in the mobile environment for the u-GIS service. However, there is no standard for the spatio-temporal data used in different spaces, spatio-temporal data processing technology is necessary to makes interoperability among mobile u-GIS services. Furthermore, it is also necessary to develop the system of gathering, storing, and managing the spatio-temporal data in consideration of small capacity and low performance of mobile devices. Therefore, in this paper, we designed and implemented a spatio-temporal query processing system based on GML to manage spatio-temporal data efficiently in the mobile environment. The spatio-temporal query processing system based on GML can offer a structured storage method which maps a GML schema to a storage table and a binary XML storage method which uses the Fast Infoset technique, so as to support interoperability that is an important feature of GML and increase storage efficiency. we can also provide spatio-temporal operators for rapid query processing of spatio-temporal data of GML documents. In addition, we proved that this system can be utilized for the u-GIS service to implement a virtual scenario.

• Journal of KIISE:Databases
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• v.33 no.2
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• pp.214-223
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• 2006

Recently there is a need to store and process enormous spatial data in spatio-temporal databases. For effective query processing in spatio-temporal databases, selectivity estimation in query optimization techniques, which approximate query results when the precise answer is not necessary or early feedback is helpful, has been studied. There have been selectivity estimation techniques such as sampling-based techniques, histogram-based techniques, and wavelet-based techniques. However, existing techniques in spatio-temporal databases focused on selectivity estimation for future extent of moving objects. In this paper, we construct a new histogram, named T-Minskew, for query optimization of past spatio-temporal data. We also propose an effective selectivity estimation method using T-Minskew histogram and effective histogram maintenance technique to prevent frequent histogram reconstruction using threshold.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04b
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• pp.61-63
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• 2002

최근 무선 환경에서 객체의 공간정보를 얻을 수 있는 기술들이 발전함에 따라 이동 객체를 대상으로 하는 여러 응용 시스템들이 등장하였다 이런 응용들의 요구사항을 만족시키기 위해서는 연속적으로 변화하는 이동 객체의 공간 정보를 저장 및 관리 할 수 있어야 하며 다양한 사용자 질의를 처리해야 한다. 그리나 기존의 이동객체 데이터베이스에 대한 연구는 실세계의 사용자 질의 처리시 질의 대상이 되는 객체나 간을 제한한다는 단점이 있다. 따라서 이 논문에서는 연속적으로 변화하는 이동 객체의 공간 정보를 관리하기 위한 데이터베이스 구조를 제시하고 이를 기반으로 사용자 질의 처리를 위한 시공간 이동 객체 연산자를 설계한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.05c
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• pp.1559-1562
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• 2003

현대의 산업화가 급격히 발전되면서 유한한 에너지에 대한 고갈 및 환경 문제가 더욱 심각해지고 있다. 이와 같은 문제들을 해결하기 위한 하나의 방법으로서 대체에너지 관리 및 서비스의 필요성이 크게 요구되고 있다. 이 논문은 국내 지역에서 측정된 대체에너지 데이터에 대한 실시간 시공간 대체에너지 관리기를 설계한다. 시공간 대체에너지 관리기는 시공간 질의 처리기, 실시간 데이터 처리기, 공간 객체 관리기, 웹 GIS 서버로 구성된다. 또한 주기적으로 측정되는 대체에너지 관련 데이터를 실시간으로 처리하여 시공간 데이터베이스를 구축하고, 웹에서 다양한 형태로 정보를 제공하는 기능을 포함한다. 시공간 질의 처리기에서 실행된 결과를 텍스트 형태로만 제시하지 않고, 그래프, 등고선, 지도정보 등과 같은 다양한 시각화를 통한 검색 서비스를 제공한다.