• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
• /
• pp.1432-1435
• /
• 1996

This paper obtains maximum allowable delay bounds for stability of network-based control systems and presents a network scheduling method which makes the network-induced delay be less than the maximum allowable delay bound. The maximum allowable delay bounds are obtained using the Lyapunov theorem. Using the network scheduling method, the bandwidth of a network can be allocated to each node and the sampling period of each sensor and controller can be determined. The presented method can handle three kinds of data (periodic, real-time asynchronous, and non real-time asynchronous data) and guarantee real-time transmissions of real-time synchronous data and periodic data, and possible transmissions of non real-time asynchronous data. The proposed method is shown to be useful by examples in two types of network protocols such as the token control and the central control.

• 제어로봇시스템학회논문지
• /
• 제17권8호
• /
• pp.783-789
• /
• 2011

Target tracking performance improvement using multi-sensor data fusion is a challenging work. However, biases in the measurements should be removed before various data fusion techniques are applied. In this paper, a bias removing algorithm using measurement data from multi-radar tracking systems is proposed and evaluated by computer simulation. To predict bias estimation performance in various geometric relations between the radar systems and target, a system observability index is proposed and tested via computer simulation results. It is also studied that target tracking which utilizes multi-sensor data fusion with bias-removed measurements results in better performance.

• 한국IT서비스학회지
• /
• 제8권1호
• /
• pp.73-97
• /
• 2009

The IT implementation literature suggests that various implementation factors play critical roles in the success of an information system; however, there is little empirical research about the implementation of data warehousing systems has unique characteristics that may impact the importance of factors that apply to it. In this study, a cross-sectional survey investigated a model of data warehousing success. Data warehousing managers and data suppliers from 51 organizations completed paired mail questionnaires on implementation factors and the success of the warehouse. The purpose of this study is to identify which factors have a positive impact on the successful implementation of DW among organizational implementation success, project implementation success, and technical implementation success which are selected as implementation factors of DW. To do so, this study comprehensively analyze the previous studies on the success factors of the information system and DW to develop the study model and set the hypothesized. Then, it verified the hypothesis via the empirical analysis after collecting the materials through the survey. Finally, the discussion of the study's results, offered the implications of the findings, and the conclusions of the findings followed.

• 한국IT서비스학회지
• /
• 제7권4호
• /
• pp.87-99
• /
• 2008

As the technologies for telecommunication have been evolving, more enhanced information services and integrated information systems have been introduced, which can manage a variety of information from the heterogeneous systems. The major obstacle for the integrated information systems is the integrating heterogeneous databases in the systems and the heterogeneity problems can be classified into the structural and data heterogeneities. However, the previous researches have mainly highlighted into the solving structural heterogeneity problems. This paper identifies the data heterogeneity problems for multi-database schema integrations and proposes a new solving method. We analyze the semantics equivalence in data values based on the functional dependency, primary and candidate keys, and present a procedural solution of data heterogeneity in the perspective of the concept of attribute equivalence, integration key and conceptual integration table.

• 한국산학기술학회논문지
• /
• 제10권10호
• /
• pp.2691-2695
• /
• 2009

오늘날 광통신 시스템은 거의 무한대의 대역폭을 지니게 되었으며 이를 통하여 다양한 멀티미디어 데이터들을 신속하게 전송하는데 사용되고 있다. 이러한 광통신 시스템 하에서 텍스트, 이미지 및 동영상 등 다양한 멀티미디어 데이터들을 송수신 하기 위해서는 통합된 통신서비스시스템의 사용이 필수적이다. 본 논문에서는 멀티 비디오데이타와 오디오 데이타를 한가닥의 광통신 라인으로 주고받을 수 있도록 해주는 광 MVAD(Multi-Video Audio Data)쌍방향 다채널 링크시스템을 개발하였다. 개발된 광링크 시스템은 오직 하나의 광케이블을 사용하여 광통신시스템을 구축 할 수 있으며 우수한 영상과 음향을 공급하는 광섬유 매개체로 인하여 다양한 분야에 적용이 가능하다.

• 대한산업공학회지
• /
• 제42권4호
• /
• pp.296-303
• /
• 2016

In public transportation, smart cards have been introduced for the purpose of convenient payment systems. The smart card transaction data can be utilized not only for the exact and convenient payment but also for civil planning based on travel tracking of citizens. This paper focuses on the analysis of the transportation convenience using the smart card big data. To this end, a new index is developed to measure the transit convenience of each region by considering how passengers actually experience the transportation network in their travels. The movement data such as movement distance, time and amount between regions are utilized to access the public transportation convenience of each region. A smart card data of five working days in March is used to evaluate the transit convenience of each region in Seoul city. The contribution of this study is that a new transit convenience measure was developed based on the reality data. It is expected that this measure can be used as a means of quantitative analysis in civil planning such as a traffic policy or local policy.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
• /
• pp.388-393
• /
• 2002

Remote sensing data is collected and analyzed to enhance understanding of the terrestrial surface. Since Landsat satellite was launched in 1972, many researches using multispectral data has been achieved. Recently, with the availability of airborne and satellite hyperspectral data, the study on hyperspectral data are being increased. It is known that as the number of spectral bands of high-spectral resolution data increases, the ability to detect more detailed cases should also increase, and the classification accuracy should increase as well. In this paper, we classified the hyperspectral and multispectral data and tested the classification accuracy. The MASTER(MODIS/ASTER Airborne Simulator, 50channels, 0.4~13$\mu$m) and Landsat TM(7channels) imagery including Yeong-Gwang area were used and we adjusted the classification items in several cases and tested their classification accuracy through statistical comparison. As a result of this study, it is shown that hyperspectral data offer more information than multispectral data.

• 한국경영과학회지
• /
• 제28권3호
• /
• pp.135-148
• /
• 2003

In this paper we introduce the Internet-based purchase support systems using data mining and case-based reasoning (CBR). Internet Business activity that involves the end user is undergoing a significant revolution. The ability to track users browsing behavior has brought the vendor and end customer's closer than ever before. It is now possible for a vendor to personalize his product message for individual customers at massive scale. Most of former researchers, in this research arena, used data mining techniques to pursue the customer's future behavior and to improve the frequency of repurchase. The area of data mining can be defined as efficiently discovering association rules from large collections of data. However, the basic association rule-based data mining technique was not flexible. If there were no inference rules to track the customer's future behavior, association rule-based data mining systems may not present more information. To resolve this problem, we combined association rule-based data mining with CBR mechanism. CBR is used in reasoning for customer's preference searching and training through the cases. Data mining and CBR-based hybrid purchase support mechanism can reflect both association rule-based logical inference and case-based information reuse. A Web-log data gathered in the real-world Internet shopping mall is given to illustrate the quality of the proposed systems.

• Journal of Computing Science and Engineering
• /
• 제2권4호
• /
• pp.394-411
• /
• 2008

The data in automation and control systems can be achieved not only from different field devices but also from different OPC (OLE for Process Control) servers. However, current OPC clients can only read and decode the simple data from OPC servers. They will have some problems to acquire structured data and exchange the structured data. In addition to the large network control systems, the OPC clients can read, write, and subscribe to thousands of data points from/to OPC servers. Due to that, the most important factor for building a high performance and scalable industrial control system is the ability to transfer the process data between server and client in the most efficient and fastest way. In order to solve these problems, we propose a means to implement the OPC DA (Data Access) server supporting the OPC complex data, so that the OPC DA clients are able to read and decode any type of data from OPC servers. We also propose a method for caching the process data in large industrial control systems to overcome the limitation of performance of the pure OPC DA system. The performance analysis and discussion indicate that the proposed system has an acceptable performance and is feasible in order for applying to real-time industrial systems today.

• 한국지형공간정보학회:학술대회논문집
• /
• 한국지형공간정보학회 2002년도 춘계학술대회 논문집
• /
• pp.119-129
• /
• 2002

The information system fields of spatial applications have rapidly grown during the last decade in Korea. Spatial data has been produced for a variety of systems without common standards until national GIS Committee defined the data exchange formats among spatial databases in the middle of 1990's. It aimed at promoting data sharing between the different systems in similar application fields. However, a considerable number of databases built prior to the introduction of the standards are not yet standard compliant but still play the roles of the main producers/consumers in the data collection field such as early developed huge AM/FM systems maintained by governmental organizations. The strong autonomy of these databases keeps their own data models, formats and descriptions from being standardized, which leads the sharing to a more difficult stage. Sharing is another way of data acquisition with least efforts and time away from direct collection. A data clearinghouse is the core module which directs users to the relevant data resources. The contents of datasets should be described with predefined metadata standards for precise indexing. Moreover, a number of technical problems have to be resolved for the common use of data between heterogeneous spatial database systems. However, the technical issues can be covered by the present information technologies. The difficulties persist in the political/institutional issues. Institutional issues are derived from the diverse sources such as political background, governmental policies, related laws and/or regulations. The paper will firstly make an analysis of current situation in terms of Korean policies, laws and regulations, secondly abstract the institutional issues from the situation analysis, lastly present guidelines for promoting spatial data sharing in Korea.