• Journal of KIISE:Databases
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• v.32 no.1
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• pp.100-110
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• 2005

The update transactions to be executed in spatial databases usually have been known as interactive and long duration works. To improve the parallelism of concurrent updates, it needs multiple transactions concurrently update a large spatial object which has a spatial extensions larger than workspace of a client. However, under the existing locking protocols, it is not possible to concurrently update a large spatial object because of conflict of a write lock This paper proposes a partial locking scheme of enabling a transaction to set locks on parts of a big object. The partial locking scheme which is an exclusive locking scheme set by user, acquires locks for a part of the big object to restrict the unit of concurrency control to a partial object of a big object. The scheme gives benefits of improving the concurrency of un updating job for a large object because it makes the lock control granularity finer.

• Journal of Convergence for Information Technology
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• v.9 no.10
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• pp.1-8
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• 2019

Generally, printers are common for users to use for public use over a wired or wireless local area network. The number of printers in the same network is increasing, and management of multiple printers is needed. To do this, a program that drives two or more printers and a computer connected by a wired or wireless network. When a computer's control department receives a print command for a designated file, it executes the steps of receiving status information from the printer, selecting the printer, and sending the print command execution. As a method of research, we presented a method for selecting differentiation from this study through prior art research and literature research. Therefore, the purpose of the study is to distribute smart print commands according to real-time status information of many printers to increase the efficiency of the printer's management, and to distribute print commands according to the cumulative and usable workload of many printers so that parts replacement of many printers can be instantaneously performed.

• Journal of KIISE:Databases
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• v.30 no.3
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• pp.310-319
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• 2003

Workflow is defined as the automation of a business process, and consists of interrelated workflow tasks. Because many modem business processes nay involve activities that are geographically distributed between different departments or organizations, workflow inherently has the characteristics of distribution. In distributed workflow systems, each workflow task performs its assigned role by utilizing information resources placed at some hosts, and then transmits workflow execution control to the next tasks in a workflow definition. Hence, it is very important to appropriately allocate workflow tasks to hosts for high performance workflow processing. In this paper, we propose a multilevel workflow graph partitioning scheme for efficient placement of workflow tasks. This method can improve the performance of workflow processing by minimizing the remote communication costs occurred during workflow execution.

• The Journal of Society for e-Business Studies
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• v.18 no.4
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• pp.45-65
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• 2013

A design file can get larger in size as the complexity of the target object increases. A large design file may reside in a large parallel computing system, such as cloud computing systems, and many designers may work concurrently on the same design file. In such a case, it is obvious that we need some kind of protection mechanism so that each user can access only the area of the file he or she is entitled to. Two approaches can be taken for this problem: one is the traditional access control mechanisms and the other encryption techniques. We take the latter approach to ensure the safety of the file even in public domain such as clouding systems, and in this paper, we suggest an encryption scheme for a file where the file is encrypted in multi-layer so that each user is allowed to access the file only at the layer for which the user has the proper access right. Each layer of the file is encrypted with different keys and these keys are exposed only to those who have the right access permit. The paper explains the necessary file format to achieve this goal and discusses the file manipulation functions to handle this new file format.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.2138.1_2139.1
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• 2009

COS 조작봉은 선로의 사고나 설비교체 또는 수리 등이 필요할 때 활선상태에서 COS를 개폐하기 위한 장비로서 보통 절연특성 및 강도가 우수하고 경량소재인 FRP(Fiberglass Reinforced Plastics)로 제작된다. 따라서 특고압 선로에서 작업 중 안전사고를 예방하기 위해 사용되는 장비인 만큼 안전거리 확보와 작업의 편리성을 고려하여 직접 조작봉을 연장하여 사용할 수 있도록 다단으로 제작되며, 조작봉의 크기는 작업조건에 따라 길이를 선택하여 사용할 수 있도록 2, 4, 6m급 등 길이에 따른 종류별로 생산되고 있다. 이러한 COS 조작봉의 사용특징은 장소와 시간에 관계없이 사용이 가능해야 하고, 특정한 사정에 의해선 작업자 혼자서 사용할 수 있도록 조작봉과 일체된 조명장치의 필요성이 항상 제기되어 왔던 문제이다. 본 논문에서는 이러한 문제점에 주안을 두고 조작봉과 일체된 전계검출에 의한 발광동작을 제어할 수 있는 발광형 COS 조작봉에 대해 각각의 구성별 요소들을 분석하고자 한다.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.4
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• pp.399-403
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• 2013

Mining diggers have been substituted with the robots for the mining works in dangerous and narrow tunnel, and those demands are increased in nowadays. In this study, experimental research on the remote controlled robots to perform after the development of the robot. According to the test results, performances of the developed robot and its working devices have been modified several times. It has been considered that the robot keeps its optimum performance in states as follows; driving speed 1.0 km/h, crawl angle $10^{\circ}$, spiking cycle 500bpm and breaking power $30kg_fm$. And also it has been found that sufficient cooling for the robot's working parts is essential to extend those working periods longer than 3 hours steadily under rating condition.

• JOURNAL OF ELECTRICAL WORLD
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• s.310
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• pp.67-72
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• 2002

미쓰비시(삼릉)전기 플랜트건설총괄부의 전력플랜트 건설공사는 수력$\cdot$화력플랜트 및 변전설비를 대상으로 하고 있으며, 수차$\cdot$수차발전기$\cdot$가스절연개폐장치(이하 ''GIS''라 한다), 변압기, 배전반 및 관련 제어기기 등의 설치 및 기기간의 배선공사 설계$\cdot$시공을 담당하고 있다. 최근의 전력플랜트를 둘러싼 일본의 시장환경은 신설 플랜트는 감소하고 갱신$\cdot$기기개수(개조, 수선) 공사의 비율이 커지고 있으며, 신설$\cdot$개보수 공사를 불문하고 공사품질의 유지와 공사비 저감을 위한 공법$\cdot$작업의 개선과 설계$\cdot$계획 업무의 합리화를 추진하여 왔다. (1) 기자재 개발에 의한 공법$\cdot$작업 개선 대형수력발전기의 로터조립용 다브테일키 박아놓기(타입)장치, 스테이터코일 분해(갱신)용 코일 엔드절단 및 코일뽑기공구, 터빈발전기 센터링용 유압잭, GIS 설치용 작업용발판을 개발하여 적용함으로써 공법 개선과 작업효율의 향상을 실현하였다. (2) 공사계획 방법의 개선 변전플랜트에서의 공기단축을 목적으로 하는 현지 설치 최적공정 책정방법의 개발$\cdot$적용, 또한 화력플랜트에서의 공사물량의 저감과 설계작업의 효율 향상을 목적으로 하는 케이블 배선 설계$\cdot$계획 방법의 개발 및 적용으로 설계업무의 개선, 공사비 저감을 도모하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1991.04a
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• pp.284-289
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• 1991

3차원 자유곡면을 볼엔드밀을 사용하여 금형가공을 할 경우, 가공면에는 공구경로에 따른 흔적과 NC공작기계의 직선보간시 발생되는 가공오차에 의하여 공작물 상에 가공오차가 필연적으로 발생되게 된다. 따라서 공작기계상에 서 금형가공을 수행한 후에는 가공오차를 제거하고 금형의 표면을 매끄럽게 하기위하여 연마작업이 픽수적으로 요구 되고있다. 본 연구에서는 3차원 자유곡면으로 이루어진 금형의 연마가공에 로봇을 도입하고, 이를 위한 로봇 작업단의 경로 제어시비전문가라 할지라도 CAM시스템으로 부터 금형 가공용 NC공작기계의 공구경로데이타(Cutter Location Data)를 받으면 자유곡면을 모형화한 후 자유곡면의 법선벡터와 연마로봇 작업단의 위치벡터를 자동으로 생성하고, 그에 따른 로봇의 작업명령을 자동으로 생성할 수 있는 CAMPoli 오프라인 로봇 프로그래밍 시스템을 개발하였다. CAMPoli시스템은 마이크로소프트사의 WINDOWS/386 오퍼레이팅 시스템을 이용하여 IBM-PC/386 상에서 개발되었으며 그주요한 내용들은 다음과 같다. i) CAM시스템으로 부터 입력된 CL-데이타로부터 연마면에 대한 자유곡면을 생성하고, ii) 연마공정의 데이타베이스에 기초한 연마면수의 지정 및 변경을 수행하고, iii) 자유곡면 연마를 위한 로봇 작업단의 위치벡터와 법선벡터를 계산하고, iv) 기존의 로봇언어를 이용한 오프라인 소스프로그램(Source Program)을 생성 및 그래픽 시뮬레이션 하는 과정으로 구축되었다.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.5
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• pp.243-254
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• 2005

Soft real-time applications such as multimedia feature highly variable processor requirements and probabilistic guarantees on deadline misses, meaning that each task in the application meets its deadline with a given probability. Thus, for such soft real-time applications, a system designer may want to improve the system utilization by allocating to each task a processor time less than its worst-case requirement, as long as the imposed probabilistic timing constraint is met. In this case, however, we have to address how to schedule jobs of a task that require more than (or, overrun) the allocated processor time to the task. In this paper, to address the overrun problem, we propose an overrun control method, which probabilistically controls the execution of overrunning jobs. The proposed overrun control method probabilistically allows overrunning jobs to complete for better system utilization, and also probabilistically prevents the overrunning jobs from completing so that the required probabilistic timing constraint for each task can be met. In the paper, we show that the proposed method outperforms previous methods proposed in the literature in terms of the overall deadline miss ratio, and that it is possible to synthesize the scheduling parameters of our method so that all tasks can meet the given probabilistic timing constraints.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.1
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• pp.40-45
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• 2004

This paper presents the parallel distributed control scheme for shaping of the bent glass. The designed system consists of a PC, a main controller and 11 servo-controllers, the precision motion controllers. Each elements are connected by using RS-232C and 8-bit data bus. In order to guarantee the stability and the control performance, we use a precision PID motion controller and a H-bridge on the servo-drivers. PC calculates position values of 11 DC motors by using the pre-determined curvature value and offers the user interface environment operator. The main controller provides the control instructions and parameter values to 11 servo-controllers by chip enable signal, simultaneously. Using the received commands and parameter values, the servo-controllers control the positions of the DC motors based on PID control scheme.