• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.9
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• pp.795-801
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• 2014

STEP Cube Lab. classified as a pico-satellite has been being developed by SSTL(Space Technology Synthesis Laboratory) in Chosun University. Its main mission objective is to perform the on-orbit verification of core space technologies, which will be the potential candidates for future space missions. In this paper, to guarantee successful mission operation of the cube satellite under extremely severe space thermal environment condition, the system level thermal design and analysis has been performed. The effectiveness of the design has been verified through on-orbit thermal analysis of cube satellite.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.5
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• pp.74-83
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• 2004

The carrier phase measurements from GPS and GLONASS have different characteristics and therefore, have to be processed with different methods to provide precise positions or attitudes. In this contribution, at first, a measurement model is derived which can be used to not only GLONASS only applications but also both GPS and GLONASS applications. And then an error analysis of the proposed method performed using the derived model to derive analytic relationships between GDOP, PDOP and RGDOP. Finally, an integer ambiguity resolution method which was used in GPS is expanded to GPS and GLONASS. The proposed results can be directly applied to the design and analysis of GLONASS receiver and application programs. Furthermore, it is expected that the suggested method can also be effectively applied to combine the characteristically different measurements from the future satellite navigation systems such as GPS modernization, Galileo and QZSS.

• Journal of the Korean Geotechnical Society
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• v.22 no.6
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• pp.51-61
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• 2006

An efficient and accurate hybrid reliability analysis method is proposed in this paper to quantify the risk of an axially loaded single pile considering pile-soil interaction behavior and uncertainties in various design variables. The proposed method intelligently integrates the concepts of the response surface method, the finite difference method, the first-order reliability method, and the iterative linear interpolation scheme. The load transfer method is incorporated into the finite difference method for the deterministic analysis of a single pile-soil system. The uncertainties associated with load conditions, material and section properties of a pile and soil properties are explicitly considered. The risk corresponding to both serviceability limit state and strength limit state of the pile and soil is estimated. Applicability, accuracy and efficiency of the proposed method in the safety assessment of a realistic pile-soil system subjected to axial loads are verified by comparing it with the results of the Monte Carlo simulation technique.

• The Journal of Korean Association of Computer Education
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• v.17 no.6
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• pp.103-113
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• 2014

This study designed and implemented a query model for consecutive analyses of dynamic multivariate graph data. First, the query model consists of two procedures; setting the discriminant function, and determining an alteration method. Second, the query model was implemented as a query system that consists of a query panel, a graph visualization panel, and a property panel. A Node-Link Diagram and the Force-Directed Graph Drawing algorithm were used for the visualization of the graph. The results of the queries are visually presented through the graph visualization panel. Finally, this study used the data of worldwide import & export data of small arms to verify our model. The significance of this research is in the fact that, through the model which is able to conduct consecutive analyses on dynamic graph data, it helps overcome the limitations of previous models which can only perform discrete analysis on dynamic data. This research is expected to contribute to future studies such as online decision making and complex network analysis, that use dynamic graph models.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.1
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• pp.76-80
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• 2008

In order to reduce a product life cycle and to improve productivity, it is required to automate the design/analysis processes. In general, since the design/analysis processes need a lot of time and resources, the various engineering resources should be integrated and utilized effectively in the distributed environments. KIMM (Korea Institute of Machinery and Materials) constructed the SOA-based e-Engineering framework to automate the execution of the design/analysis processes and to integrate the engineering resources in the distributed environments. This paper presents the concepts and the structures of the e-Engineering framework. Also it classifies the exceptional cases that will be able to occur in the e-Engineering framework and suggests the recovery techniques from the exceptional cases with viewpoints of the engineering process and the task, respectively.

• Korean Journal of Optics and Photonics
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• v.18 no.6
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• pp.410-420
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• 2007

We theoretically derive the set of utilizable paraxial zoom locus equations for all complicated zoom lens systems with infinite object distance, such as a camera zoom lens, by using the Gaussian bracket method and the matrix representation of paraxial ray tracing. And we make the zoom locus program according to these equations in Visual Basic. Since we have applied the paraxial ray tracing equations into Gaussian bracket representation, the resultant program systematically simplifies various constraints of the zoom loci of various N group types. Consequently, the solutions of this method can be consistently used in all types of zoom lens in the step of initial design about zoom loci. Finally, in order to verify the usefulness of this method, we show that one example among 4 groups and that among 5 groups, which are very complex zoom lens systems, can be rapidly and with versatility traced through various interpolations by using this program.

• The Transactions of the Korea Information Processing Society
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• v.3 no.2
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• pp.283-294
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• 1996

To operate the automatic devices of manufacturing process more effectively and to solve the needs of the resource sharing, network technology is applied to the unit control devices located in common manufacturing zone and operated by connecting them. This paper introduces deign and test operation of cell system for the management of multivendor PLC by applying to wall paper process based on the manufacturing standardization of CIM. The analysis of designed multivendor PLC group is performed by selecting the parameters such as variation of data packet size and node number of PLC ladder logic program and variation by analyzing the corresponding variation values of token rotation time and waiting time for the system operation. For the method of the analysis,the equation is considering the overhead such as indicated packet service time and transmission safety margin for PLC network connection in M/G/1 queue model,and it is applied to the cell system and PLC group manage-ment for operation .Through the experiment,it is found that the realtime processing is possible with expanded and better result than the resuit obtained by Jayasumana.Browaka with PLC scan time considered,response lower limit of 10-20 msec. data packet size not more than 50 bytes.and the number of nodes less than 40.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.333-340
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• 2018

Recently, free-form buildings have been designed with complex shapes due to digitization of the construction industry. Exterior and interior components of free-form buildings have free cross sections and curved shapes. Therefore, structural members with curvature are frequently seen. In the modeling and stability evaluation of these structures, commercial programs using classical finite element analysis are not able to perform rapid shape modeling, resulting in a decrease in productivity. Therefore, in this study, pre- and post-processing modules were developed using a prior study to rapidly model the surface of a free-form building and to automatically generate frame structures that make up the cladding. The developed modules use a subdivision algorithm with spline curves. This algorithm is used to automatically generate analytical elements from the configuration information of NURBS curves. In addition, the deformation after analysis can be viewed more realistically. The modules can quickly construct complex curved surfaces. An analysis model of the frame structure was also automatically generated. Therefore, the modules could contribute to the productivity improvement of free-form building design.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1819-1823
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• 2007

유역에서 상류 유역 또는 수변을 따라 자연 자원을 이용하여 조성되어야 할 완충지대는 비점오염의 영향을 줄이기 위한 중요한 최적 관리공법이다. 교란된 토지 피복과 수변 완충지대를 관리 및 복원할 때 같은 지형조건이라도 식생 종류, 발달정도, 토양조건에 따라 오염물 제거효과가 다를 수 있으며, 최소 완충지대 길이도 제거 오염물질 대상별로 적합하게 설계되고 해석되어야 한다. 본 연구의 목적은 용담댐 유역에서 SWAT 모델을 이용하여 식생 완충지대의 비점오염원 저감 모의 재현성을 평가하는 것이였다. 소유역의 관측값과 모델 예측값에 대한 모델의 검 보정이 선행되었으며 그 중에서 가장 높은 모델 효율을 가지는 소유역에서 three zone concept의 90m 수변완충지대를 지방하천을 경계로 하여 토지 피복도를 변화시켜 SWAT 모델에 적용하였다. 이 때 교목으로는 포플러 (Populus, 30m)을 적용하였고, 포플러의 높이 및 Leaf area index를 조정하여 관목 지대(30m)에 입력하였다. 잔디 지대(30m)는 자연초지를 선택하였다. 또한 지형변수(average slope)와 Manning's coefficient을 수변완충지대의 조건에 고려하여 변화를 주었고 이에 따른 유출량 및 유사량, T-N, T-P의 변화율을 조사하였다. 또한 5, 10, 30m의 식생 여과대를 밭 지역에만 적용하여 오염물의 저감 효율을 평가하였다. SWAT 모델은 각 소유역에서 발생된 전반적인 유출량과 수질변수의 추세를 잘 예측하였으며 정자천 소유역이 선택되었다. 모의된 완충지대에서는 연평균 940 m3/ha의 유출량이 감소되는 것으로 유사농도는 28.7 %의 저감효과를 보였다. 그러나 T-N, T-P의 농도는 오히려 증가되었는데 본 연구에서 고려된 보다 수변완충지대를 조성할 때 지하수 수위, 식생 성장변화 등과 같은 보다 정확한 설계 인자 산출 및 모델 DB 개발이 유역모델에 포함되어야 할 것으로 판단되었다.한 해결책을 얻어내는 상호보완적인 결과를 추구한다. 그가 디자인하는 작품은 전형적인 이미지를 내포하지 않는다. 즉 그의 작품은 기존의 가치와 이념적인 것은 배제하고, 창의적인 개념을 도출하였다.형모서리는 건물 특화 성격이 강하므로 불가피할 경우 소형 액센트 광고 위치를 미리 벽면으로 할애하는 것이 경관 및 입면계획에 유리한 것으로 분석되었다. 불확실도 해석모형 등의 새로운 기능을 추가하여 제시하였다. 모든 입출력자료는 프로젝트 단위별로 운영되어 data의 관리가 손쉽도록 하였으며 결과를 DB에 저장하여 다른 모형에서도 적용할 수 있도록 하였다. 그리고 HyGIS-HMS 및 HyGIS-RAS 모형에서 강우-유출-하도 수리해석-범람해석 등이 일괄되게 하나의 시스템 내에서 구현될 수 있도록 하였다. 따라서 HyGIS와 통합된 수리, 수문모형은 국내 하천 및 유역에 적합한 시스템으로서 향후 HydroInformatics 구현을 염두에 둔 특화된 국내 수자원 분야 소프트웨어의 개발에 기본 토대를 제공할 것으로 판단된다.았다. 또한 저자들의 임상병리학적 연구결과가 다른 문헌에서 보고된 소아 신증후군의 연구결과와 큰 차이를 보이지 않음을 알 수 있었다. 자극에 차이가 있지 않나 추측되며 이에 관한 추후 연구가 요망된다. 총대장통과시간의 단축은 결장 분절 모두에서 줄어들어 나타났으나 좌측결장 통과시간의 감소 및 이로 인한 이 부위의 통과시간 비율의 저하가 가장 주요하였다. 이러한 결과는 차가운 생수 섭취가 주로 결장 근위부를 자극하는 효과를 발휘하는 것이 아닌가 해석된다. 이와 같은 연구결과를 통해 생다시마를 주원료로 개발된 생다시마차와 생다시마 음료가 만성 기능성 변비 증세를 개선하는 효능이 잠재적으로 있음을 확인하였다. 그러나 생약제재의 변비약 수준으로 변비 개선 효능을 증대하기 위해서는 재료 배합비의 개선이나 대장 운동기능을 향상시키는 유효성분의 보강 등이 필요하다는 점도 알 수 있었다.더불어 산화물질 해독에 관

• Journal of the Society of Naval Architects of Korea
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• v.35 no.2
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• pp.51-62
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• 1998

In this paper, a CAD/CAM system for 5-axis machining of model propeller is introduced. This system has been developed under the environment of personal computer and Windows NT. In order to enhance the productivity, existing text-based design S/W was integrated into this graphic-based system. Non-Uniform Rational B-Spline method is used to represent the sculptured surface of propeller blades and hub using point data, and surface blending between blade and hub is realized in this system. For 5-axis machining of sculptured surface, tool/work collision and interference are checked and inverse kinematic analysis is performed to make NC data. In addition, tool and workpiece are animated on the PC monitor by preparing NC verification module. Finally, optimal cutting conditions are determined empirically and those cutting conditions are integrated into this S/W so that the whole process from design to machining can be done automatically.