• The KIPS Transactions:PartD
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• v.9D no.5
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• pp.847-858
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• 2002

A purpose of the object-oriented programming is to promote reuse and development time, and to improve software quality. A way for this purpose is using a design information well-defined and tested in previous time when developing software. Such design information is called design patterns. The design patterns are descriptions of abstract solution to recurse software design problems In a systematic and general way. But because the design patterns are descriptions of abstract solution, the specification and application of patterns generally rely on manual implementation and is applied to various forms. As a result, we need to spend a lot of time to develop software program not only because of difficulty in analyzing and applying to patterns consistently, but also because of the frequent programing faults. And because the applied design patterns don't express inside application visually, it is difficult to analyze and test for this design patterns. In this paper, we propose automatic source code generating technique to be able to efficiently apply the element of design patterns when developing application. And we show a way to analyze and use the applied design patterns in application. As a result, the design patterns in application provide the consistent structure and efficiency, and make analysis and using effect increased.

• Journal of Energy Engineering
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• v.27 no.2
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• pp.1-13
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• 2018

The proportion of natural gas-fueled power generation is expanding due to the change of domestic energy policy pursuing reduction of dust and increasing clean energy consumption. Natural gas fuels used for the combined-cycle power plants and the district-heating power plants are operated at high temperature and high pressure in the fuel supply system. Accidents due to leakage of the gas such as fire and explosion should be prevented by applying risk management techniques. In this study, risk assessment was performed on the natural gas fuel supply system of a combined power plant based on the API RP 581 RBI code. For the application of the API RBI code, lines and segments of the evaluation target system were identified. Operational data and input information were analyzed for the calculations of probability of failure and consequence of failure. The results of the risk assessment were analyzed over time from the initial installation time. In the code-based evaluation, the gas fuel supply system was mainly affected by thinning, external damage, and mechanical fatigue damage mechanisms. As the operating time passes, the risk is expected to increase due to the external damage caused by the CUI(Corrosion Under Insulation).

• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.6
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• pp.511-524
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• 2016

Since a room-and-pillar underground structure is characterized by its grid-type array of room and pillar, its economical efficiency can be governed by excavation sequence. In this study, the construction period by the drill-and-blast method as a excavation method for a room-and-pillar underground structure was examined. In addition, the parallel excavation sequence was considered as the main sequence of a room-and-pillar underground structure. Sequences of mucking and support installation were derived to estimate the total excavation cycle by taking the case of a road tunnel into consideration. From the excavation cycle of room-and-pillar underground structure, the relationship between available maximum and minimum numbers of jumbo drill machines depending on the number of faces in operation was suggested.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.11a
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• pp.75-89
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• 2006

한국전력산업의 탈규제화의 영향으로 각 개별 발전회사들은 자사의 이익을 최대화하기 위한발전계획 수립에 큰 관심을 가지게 되었다. 발전계획은 주어진 연료제약 하에 발전수익과 유지보수비용을 고려하여 시간대별 발전기의 기동, 정지 및 발전출력을 결정하는 문제로서Profit-Based Unit Commitment (PBUC) 문제로 알려져 있다. PBUC 문제는 문제 자체의 복잡성과 비선형 제약식의 특성으로 인하여 과거 연구는 대부분 비선형 제약식 처리를 위한 Lagrangian Relaxation (LR) 기반 휴리스틱 접근법에 초점이 맞추어져 왔다. 하지만, 실제현업 적용에 있어 계산시간이 많이 소요되고 알고리즘의 구현에 많은 기간이 소요되어 실용성은 낮은 것으로 보고되었다. 특히 연료도입 및 저장제약을 고려하기 위한 1년 단위 장기 발전계획 수립은 문제의 범위가 더욱 넓어짐으로 인하여 복잡성이 매우 크게 증가하고, 이에 따라 기존 접근법에 한계가 있어 왔다. 이에 본 연구에서는 국내가스발전소의 사례를 중심으로 발전패턴개념의 도입 및 다양한 발전패턴 생성을 통한 Explicit Column Generation 기반 최적화 접근법을 제안한다. 발전패턴은 Column Generation 접근법의 각 Column에 해당하는 각주별 발전기 기동정지계획을 의미한다. 즉, 미리 유효한 발전패턴의 Pool을 최대한 확보한 후 Explicit Column Generation Formulation을 통하여 주별 최적의 발전패턴을 찾아내는 알고리즘으로 구성이 된다. 본 알고리즘은 실제 가스발전소의 장기 발전계획 수립과정에 적용되어 효과적으로 운용되고 있으며 연간 수십억원의 추가적인 이익을 실현할 것으로 분석되었다. 본 알고리즘을 확장 적용할 경우 PBUC 문제 해결을 위한 새로운 해법으로도 그 효용성이 클 것으로 예상된다.자료이기 때문에 통계적 활용의 범위가 방대하다. 특히 개인, 가구, 사업체 등 사회 활동의 주체들이 어떻게 변화하는지를 추적할 수 있는 자료를 생산함으로써 다양한 인과적 통계분석을 할 수 있다. 행정자료를 활용한 인구센서스의 이러한 특징은 국가의 교육정책, 노동정책, 복지정책 등 다양한 정책을 정확한 자료를 근거로 수립할 수 있는 기반을 제공한다(Gaasemyr, 1999). 이와 더불어 행정자료 기반의 인구센서스는 비용이 적게 드는 장점이 있다. 예를 들어 덴마크나 핀란드에서는 조사로 자료를 생산하던 때의 1/20 정도 비용으로 행정자료로 인구센서스의 모든 자료를 생산하고 있다. 특히, 최근 모든 행정자료들이 정보통신기술에 의해 데이터베이스 형태로 바뀌고, 인터넷을 근간으로 한 컴퓨터네트워크가 발달함에 따라 각 부처별로 행정을 위해 축적한 자료를 정보통신기술로 연계${cdot}$통합하면 막대한 조사비용을 들이지 않더라도 인구센서스자료를 적은 비용으로 생산할 수 있는 근간이 마련되었다. 이렇듯 행정자료 기반의 인구센서스가 많은 장점을 가졌지만, 그렇다고 모든 국가가 당장 행정자료로 인구센서스를 대체할 수 있는 것은 아니다. 행정자료로 인구센서스통계를 생산하기 위해서는 각 행정부서별로 사용하는 행정자료들을 연계${cdot}$통합할 수 있도록 국가사회전반에 걸쳐 행정 체제가 갖추어져야 하기 때문이다. 특히 모든 국민 개개인에 관한 기본정보, 개인들이 거주하며 생활하는 단위인 개별 주거단위에 관한 정보가 행정부에 등록되어 있고, 잘 정비되어 있어야 하며, 정보의 형태 또한 서로 연계가 가능하도록 표준화되어있어야 한다. 이와 더불어, 현재 인구센서스에서 표본조사를 통해 부가적으로 생산하는 경제활동통계를 생산하기 위해서는 개인이 속한 사업체를 파악할 수 있도록 모든 사업체가 등록되어

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.7B
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• pp.585-597
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• 2004

In this paper, we propose the functional models of optical burst switching (OBS) routers to apply GMPLS (Generalized Multiprotocol Label Switching) to optical networks based on OBS. In addition, we introduce a connection admission control (CAC) algorithms which are operated in this models and can accommodate the required QoS. Firstly, the characteristics of current GMPLS and OBS for the optical Internet are basically considered. With this consideration, the models are proposed to accept OBS features which include the recognition of data boundary with control information and the statistical multiplexing in terms of bursts. Secondly, we use an offset time decision (OTD) algorithm on behalf of controlling the connection admission with taking QoS parameters such as burst loss rate(BLR) and service-differentiation ratio(SDR) into consideration. The proposed CAC algorithms use the offered load of LSP (Label Switched Path), wavelength information, and QoS parameters as inputs of OTD algorithm. A call setup request will be accepted when the offset time decided by OTD algorithm is reasonable for guaranteeing its requested QoS. Simulation is used for performance evaluation. Results show the proposed schemes can guarantee the required QoS and those are better than the previous one in terms of channel utilization.

• Journal of the Korean Geosynthetics Society
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• v.10 no.2
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• pp.35-43
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• 2011

Permeable Reactive Barriers (PRB) method is an economical method that does not require any other methods to be operated once it is installed as it controls of groundwater flow in the barrier, which is inserted a reactive material on the way of pollutant. The major dominant element of PRB is a reactive material in the reactive wall, and such factors as purification efficiency and used time based on the chemical and physical features in between the reactant and pollutant. High purification efficiency can be expected when a rational design that is synthetically considered in features of packing density, operation period, and adsorption reactant of pollutant. A column test was conducted for an application test using CFW as its adsorption reactant in order to remove copper($Cu^{2+}$) in the PRB system. The CFW was used for the reactant and selected inflow speed, density and thickness of PRB as its necessary factors for design of PRB. As a result of the experiment, the removal efficiency decreased as operating time of PRB increased and the efficiency linearly increased upon the length. Therefore, it is confirmed that the thickness of reactive materials in PRB system can be designed using the proposed formula considering purification time and density of CFW.

• Journal of IKEEE
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• v.1 no.1 s.1
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• pp.31-46
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• 1997

In this paper, a parallel Optimal Best-First search Branch-and-Bound(B&B) algorithm(pobs) is designed and evaluated for MIN-based multiprocessor systems. The proposed algorithm decomposes a problem into G subproblems, where each subproblem is processed on a group of P processors. Each processor group uses tile sub-Global Best-First search technique to find a local solution. The local solutions are broadcasted through the network to compute the global solution. This broadcast provides not only the comparison of G local solutions but also the load balancing among the processor groups. A performance analysis is then conducted to estimate the speed-up of the proposed parallel B&B algorithm. The analytical model is developed based on the probabilistic properties of the B&B algorithm. It considers both the computation time and communication overheads to evaluate the realistic performance of the algorithm under the parallel processing environment. In order to validate the proposed evaluation model, the simulation of the parallel B&B algorithm on a MIN-based system is carried out at the same time. The results from both analysis and simulation match closely. It is also shown that the proposed Optimal Best-First search B&B algorithm performs better than other reported schemes with its various advantageous features such as: less subproblem evaluations, prefer load balancing, and limited scope of remote communication.

• Journal of Broadcast Engineering
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• v.14 no.6
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• pp.692-702
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• 2009

Real-time virtual studios which could run only on expensive workstations are now available for personal computers thanks to the recent development of graphics hardware. Nevertheless, graphics are rendered off-line in the post production stage in film or TV drama productions, because the graphics' quality is still restricted by the real-time hardware. Software-based camera tracking methods taking only the source video into account take much computation time, and often shows unstable results. To overcome this restriction, we propose a system that stores camera motion data from sensors at shooting time as common virtual studios and uses them in the post production stage, named as POVIS(post virtual imaging system). For seamless registration of graphics onto the camera video, precise zoom lens calibration must precede the post production. A practical method using only two planar patterns is used in this work. We present a method to reduce the camera sensor's error due to the mechanical mismatch, using the Kalman filter. POVIS was successfully used to track the camera in a documentary production and saved much of the processing time, while conventional methods failed due to lack of features to track.

• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.5
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• pp.464-470
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• 2010

The integrity of the industrial equipment in use under high temperature and high pressure must be assessed by regularly measuring the degraded mechanical properties during service time. In order to nondestructively monitor the degraded mechanical properties of industrial equipment, a measuring method of the reversible permeability(RP) using surface type probe is presented. The method for measuring the RP is based on that RP is the differential value of hysteresis loop. The RP is exactly the foundation hatmonics induced in a detecting coil measured by lock-in amplifier tuned to a frequency of the alternating perturbing magnetic field. The peak of RP is measured around the coercive force. Steel material used in this work was 12Cr ferritic heat resisting steel. The eleven kinds of samples aged during different times under same temperature ($700^{\circ}C$) were prepared. Peak interval of reversible permeability(PIRP), Vickers hardness, and tensile strength measured for the aged samples decreased abruptly for short aging time (below 500 h), but the change became small at a long aging time. Vickers hardness and tensile strength linearly decreased as RIRP decreased, so the degraded mechanical properties of 12Cr ferritic heat resisting steel could be nondestructively evaluated by measuring RIRP.

• The Journal of Society for e-Business Studies
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• v.12 no.3
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• pp.211-234
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• 2007

In e-business, XML is a major format of data and it is essential to efficiently process queries against XML data. XML query caching has received much attention for query performance improvement. In employing XML query caching, some efficient technique of cache replacement is required. The previous techniques considered as a replacement unit either the whole query result or the path in the query result. The former is simple to employ but it is not efficient whereas the latter is more efficient and yet the size difference among the potential victims is large, and thus, efficiency of caching would be limited. In this paper, we propose a new technique where the element in the query result is are placement unit to overcome the limitations of the previous techniques. The proposed technique could enhance the cache efficiency to a great extent because it would not pick a victim whose size is too large to store a new cached item, the variance in the size of victims would be small, and the unused space of the cache storage would be small. A technique of XML semantic cache replacement is presented which is based on the replacement function that takes into account cache hit ratio, last access time, fetch time, size of XML semantic region, size of element in XML semantic region, etc. We implemented a prototype XML semantic cache system that employs the proposed technique, and conducted a detailed set of experiments over a LAN environment. The experimental results showed that our proposed technique outperformed the previous ones.