• Journal of the Korea Society of Computer and Information
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• v.14 no.1
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• pp.217-228
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• 2009

Data analysis applications typically aggregate data across many dimensions looking for unusual patterns in data. Even though such applications are usually possible with standard structured query language (SQL) queries, the queries may become very complex. A complex query may result in many scans of the base table, leading to poor performance. Because online analytical processing (OLAP) queries are usually complex, it is desired to define a new operator for aggregation, called the data cube or simply cube. Data cube supports OLAP tasks like aggregation and sub-totals. Many aggregate functions can be used to construct a data cube. Those functions can be classified into three categories, the distributive, the algebraic, and the holistic. It has been thought that the distributive functions such as SUM, COUNT, MAX, and MIN can be used to construct a data cube, and also the algebraic function such as AVG can be used if the function is replaced to an intermediate function. It is believed that even though AVG is not distributive, but the intermediate function (SUM, COUNT) is distributive, and AVG can certainly be computed from (SUM, COUNT). In this paper, however, it is found that the intermediate function (SUM COUNT) cannot be applied to OLAP cubes, and consequently the function leads to erroneous conclusions and decisions. The objective of this study is to identify some problems in applying aggregate function AVG to OLAP cubes, and to design a process for solving these problems.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.176-179
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• 1998

In structural analysis using FEM or BEM, pre_ and post_processor is necessary pre_ and post_processor and analyzer use same structural model. But many other tasks related to structural design, such as optimization, design of layout, etc, do not share that model in spite of their resemblance of requiring data. So, a pre_ and post_ processor was developed using a relational database managing system. Developed system uses the DBMS as a data storage and interacts with it using SQL interface. In this way, many other tasks that uses same structural data can be developed.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1586-1589
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• 2007

A prototype high-speed train system, Hanvit-350, has been developed in Korea since 1996. The train has reached the maximum speed of 352.4km/h during a test run on December 2004. It is presently undergoing various tests to stabilize its performance and to secure reliability. Until now, around 420 runs have been conducted and accumulates 190,000km trial run. The test database management program is developed using existing analysis program, LabVIEW and database program, Microsoft-SQL. The test database management program is used to analysis of test results and will be used to find out the correlation characteristics between parameters.

• Proceedings of the Korean Society of Computer Information Conference
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• 2008.06a
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• pp.175-182
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• 2008

2008년에 있었던 우리나라 금융기관과 정부기관에 대한 DoS 공격에 대한 연구이다. 실험실 환경에서 실제 DoS 공격 툴을 이용하여 공격을 실시한다. DoS 공격을 탐지하기 위하여 네트워크 상에서 Snort를 이용한 N-IDS를 설치하고, 패킷을 탐지하기 위한 Winpcap과 패킷의 저장 및 분석하기 위한 MySQL, HSC, .NET Framework 등을 설치한다. e-Watch 등의 패킷 분석 도구를 통해 해커의 DoS 공격에 대한 패킷량과 TCP, UDP 등의 정보, Port, MAC과 IP 정보 등을 분석한다. 본 논문 연구를 통하여 유비쿼터스 정보화 사회의 역기능인 사이버 DoS, DDoS 공격에 대한 자료를 분석하여 공격자에 대한 포렌식자료 및 역추적 분석 자료를 생성하여 안전한 인터넷 정보 시스템을 확보하는데 의의가 있다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.4
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• pp.523-528
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• 2015

A new algorithm for a coordinative control method is proposed with respect to voltage control and system stabilization of local substations. This is accomplished using control cooperation between a static synchronous compensator (STATCOM) and the existing voltage compensation equipment in the steady state and emergency state of a power system. A real-time system analysis was developed by combining a system analysis program with InTouch, which has primarily been used in factory automation for verification. PSS/E was used for the load flow calculation software, Python for language, Intouch as an HMI program, and MS SQL for the database. To test this system, the system in the vicinity of the Migeum and the Migeum substations was modeled and simulated.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.1126-1131
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• 2006

Risk assessment of a railway system should be periodically conducted managing a large amount of accumulating accident/incident data and scenarios, which generally requires enormous time and efforts. Therefore, special information management system is essential for railway risk assessment, where data needed for decisions on managing the railway safety could be promptly supported. The objective of this study is to develop a railway accident analysis program for risk assessment. The program is application running on the web which links railway accident analysts throughout the railway industry to a central database. Data entered, together with associated code tables. is stored on MS-SQL database. The program uses the concepts of accident, safety events, causes, related factors(vehicle, person, infrastructure, tool/equipment), recommendations to bring together the various elements of railway accidents. The program will be useful in finding hazard conditions, accident scenarios, quantitatively assessing the risk, and providing pertinent risk measures, eventually serving to prevent railway accidents and reduce severities of railway accidents.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.27 no.4
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• pp.179-186
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• 2004

The purpose of this study is to implement web-based quality cost management system to measure the performance of quality improvement activities in the business firms. Developed WQCMS(Web-based Q-Cost Management System) have ability to collect and analyze quality data generated from various different departments in the inside or outside of the enterprise without any limitations, if end-users are able to access wide area network. It provides the capability to integrate quality information from database and to generate various easy analysis reports to management's needs using built-in analysis tool modules with real-time. The proposed system was developed using Microsoft's .Net technology, ASP.NET and MS-SQL Server 2000. By web-enabling Q-cost management system, the effectiveness of the system management and utilization was realized by easiness of information integration and economical efficiency.

• Journal of Digital Convergence
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• v.13 no.12
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• pp.135-142
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• 2015

Appearance and rapid growth of the social network services (SNS) have led to changes in the distribution structure of information. Consumers can obtain various information quickly via the social network services and companies make use of a new advertising channel in them. In order to increase the effect of publicity activities through the social network services, development and application of public relations strategy by evaluating and analyzing the results of the activities is required. In this paper, a method for developing a low cost system to evaluate and analyze the results of public relations through the social networks is proposed. The proposed method was verified through building and running a demo system to collect and analyze data in the Facebook fan pages using MySQL database and PHP script on a Linux server.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.7
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• pp.791-797
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• 2014

In order to create an environment for Apache Hadoop for parallel distributed processing system of Bigdata, by connecting a plurality of computers, or to configure the node, using the configuration of the virtual nodes on a single computer it is necessary to build a cloud fading environment. However, be constructed in practice for education in these systems, there are many constraints in terms of cost and complex system configuration. Therefore, it is possible to be used as training for educational institutions and beginners in the field of Bigdata processing, development of learning systems and inexpensive practical is urgent. Based on the Raspberry Pi board, training and analysis of Big data processing, such as Hadoop and NoSQL is now the design and implementation of a learning system of parallel distributed processing of possible Bigdata in this study. It is expected that Bigdata parallel distributed processing system that has been implemented, and be a useful system for beginners who want to start a Bigdata and education.

• Journal of KIISE
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• v.43 no.11
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• pp.1216-1222
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• 2016

The advent of large-scale web services has resulted in gradual increase in the amount of data used in those services. These big data are managed efficiently by DBMS such as MySQL and MariaDB, which use InnoDB engine as their storage engine, since InnoDB guarantees ACID and is suitable for handling large-scale data. To improve I/O performance, InnoDB caches data and index of its database through a buffer pool. It also supports multiple buffer pools to mitigate lock contentions. However, the multiple buffer pool scheme leads to the additional data consistency overhead. In this paper, we analyze the overhead of the multiple buffer pool scheme. In our experimental results, although multiple buffer pool scheme mitigates the lock contention by up to 46.3%, throughput of DMBS is significantly degraded by up to 50.6% due to increased disk I/O and fsync calls.