• Proceedings of the Korea Society for Simulation Conference
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• 2001.05a
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• pp.143-143
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• 2001

조선 산업에서의 이익 극대화를 위해서는, 공기 단축을 통한 매출 증대, 주어진 생산 자원(인력, 설비 등)의 효율적인 이용을 통한 생산비 절감이 필수적인 사안이다. 다시 말하면, 효율적인 자원의 이용으로 선박의 건조 공기를 줄임으로써 조선 산업에서의 이익 극대화를 도모할 수 있고 이는 효과적인 생산 계획과 관리를 통해 얻을 수 있다. 조선 산업에서의 생산 계획과 관리는 내업, 선행, 선내 등 선박 건조의 전 과정에서 이루어지고 있는데, 조선 산업은 타 산업에 비해 환경변화에 따른 단기간의 불확실성은 비교적 적은 반면에, 가공, 절단, 조립, 의장, 도장, 선행탑재, 탑재, 안벽 작업 등 다단계 제조 프로세스가 장기간에 걸쳐 상당히 복잡하게 구성되어 있다. 또한, 유연하게 적용할 수 있는 인적자원과 공정순서, 그리고 각종 시간적 공간적 자원 제약 등으로 인하여 효과적이고 일관된 생산 계획을 신속하게 수립하기가 어려울 뿐만 아니라, 주문 생산 방식이기 때문에 정확한 일정계획 데이터의 생성도 어려운 실정이다. 본 연구는, 조선의 혁신적인 생산관리 능력 향상을 지원하기 위한 "조선 통합 생산계획 시스템 개발" 에 관련된 연구이다. 본 연구에서는 조선 생산계획에 적합한 일정계획 방법론 및 엔진 소프트웨어를 활용하고 총체적인 생산계획 및 일정계획 업무의 개념 재정립을 통하여, 통합 최적화를 실시간에 지원하는 조선 최적 일정계획 시스템 구축에 궁극적인 목적을 두고 있다. 이를 위해 본 연구에서는 조선 프로세스와 일정계획 업무규칙을 분석하고 이를 바탕으로 "조선 최적 일정계획 시스템"을 개발하였다. 조선 최적 일정계획 시스템은 블록, PE, 탑재, 선내 단계의 일정계획 최적화와 What-if Simulation을 지원하기 위하여 ILOG Solver/scheduler로 구현하였으며, 구현된 시스템에 대해 실제 계획에서 사용하는 데이터를 대상으로 다양한 최적화 기능에 대한 실험을 실시하였다. 실제 데이터를 이용한 실험결과, 풀이시간과 최적해 측면 모두에서 비교적 만족할 만한 결과를 보여주었다.교적 만족할 만한 결과를 보여주었다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.5
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• pp.552-560
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• 2013

In this paper, an optimization algorithm for the block assembly accuracy control assessment is proposed with consideration for the current block assembly process and accuracy control procedure used in the shipbuilding site. The objective function of the proposed algorithm consists of root mean square error of the distances between design and measured data of the other control points with respect to a specific point of the whole control points. The control points are divided into two groups: points on the control line and the other points. The grouped data are used as criteria for determining the combination of 6 degrees of freedom in the registration process when constituting constraints and calculating objective function. The optimization algorithm is developed by using combination of the sampling method and the point to point relation based modified ICP algorithm which has an allowable error check procedure that makes sure that error between design and measured point is under allowable error. According to the results from the application of the proposed algorithm with the design and measured data of two blocks data which are verified and validated by an expert in the shipbuilding site, it implies that the choice of whole control points as target points for the accuracy calculation shows better results than that of the control points on the control line as target points for the accuracy of the calculation and the best optimized result can be acquired from the accuracy calculation with a fixed point on the control line as the reference point of the registration.

• The KIPS Transactions:PartB
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• v.15B no.4
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• pp.259-268
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• 2008

In an effort to increase the data capacity of one-dimensional symbology, 2D barcodes have been proposed a decade ago. In this paper, we present an effective 2D barcode detection algorithm from gray-level images, especially for the handheld 2D barcode recognition system. To locate the symbol inside the image, a criteria based on the block contrast is adopted, and a gray-scale projection with sub-pixel operation is utilized to segment the symbol precisely from the region of interest(ROI). Finally, the segmented ROI is normalized using the inverse perspective transformation for the following decoding processes. We also introduce the post-processing steps for decoding the QR-code. The proposed method ensures high performances under various lighting/printing conditions and strong perspective deformations. Experiments shows that our method is very robust and efficient in detecting the code area for the various types of 2D barcodes in real time.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.9
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• pp.5419-5424
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• 2014

A weld scallop is a small quadrant or half circle type hole installed in the weld line cross area for easy welding operation. Many types of T-bars with a scallop can be welded in a block assembly stage in shipbuilding. The difficulties arise from the fact that scallops are to be filled by build-up welding after welding of the cross line is complete. In this study, a non-scallop block joint welding method was developed using special type CBM (ceramic backing material). The wedge shaped CBM was devised to insert a CBM into just the V groove of weld line cross area without weld scallop. A saw-toothed shape was adopted for easy cutting of the unnecessary part in the CBM fitting process. The applicability of the developed method was verified through welding experiments based on the yard welding conditions.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.2
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• pp.177-186
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• 2009

Nowadays, as going to information society based knowledge, the informations are acquired, processed, serviced based digital environment. In surveying field, the trend have been changed from the analog foundation to the digital foundation. Also, aerial photogrammetry is being changed from analog aerial photogrammetry to digital aerial photogrammetry. In this paper, the analysis of accuracy is performed for the comparison of traditional aerial photogrammetry with digital aerial photogrammetry usign UltracamX in AT and Block Adjustment. As the results, Bundle adjustment in digital aerial photogrammetry with GPS/INS have more advantages than traditional independent adjustment in analog aerial photogrammetry. Digital aerial photogrammetry contributes the higher accuracy in AT and block adjustment more than analog aerial photogrammetry.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.5
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• pp.207-216
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• 2023

For decoding-compatible parallel Deflate algorithm, this study proposed a new method of the control header being made in such a way that essential information for parallel compression and decompression are stored in the Disposed Bit Area (DBA) of the non-compression block and being inserted into the compressed blocks. Through this, parallel compression and decompression are possible while maintaining perfect compatibility with the existing decoder. After applying this method, the compression time was reduced by up to 71.2% compared to the sequential processing method, and the parallel decompression time was reduced by up to 65.7%. In particular, it is well known that parallel decompression is impossible due to the structural limitations of the Deflate algorithm. However, the decoder equipped with the proposed method enables high-speed parallel decompression at the algorithm level and maintains compatibility, so that parallelly compressed data can be decoded normally by existing decoder programs.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.4
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• pp.363-371
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• 2023

To construct a ship, blocks of various sizes must be moved and erected . In this process, lugs are used such that they match the block fastening method and various functions suitable for the characteristics of each shipyard facility. The sizes and shapes of the lugs vary depending on the weight and shape of the block structures. The structure is reinforced by welding the doubling pads to compensate for insufficient rigidity around the holes where the shackle is fastened. As for the method of designing lugs according to lifting loading conditions, a simple calculation based on the beam theory and structural analysis using numerical modeling are performed. In the case of the analytical method, a standardized evaluation method must be established because results may differ depending on the type of element and modeling method. The application of this ambiguous methodology may cause serious safety problems during the process of moving and turning-over blocks. In this study , the effects of various parameters are compared and analyzed through numerical structural analysis to determine the modeling conditions and evaluation method that can evaluate the actual structural response of the lug. The modeling technique that represents the plate part and weld bead around the lug hole provides the most realistic behavior results. The modeling results with the same conditions as those of the actual lug where only the weld bead is connected to the main body of the lug, showed a lower ulimated strength compared with the results obtained by applying the MPC load. The two-dimensional shell element is applied to reduce the modeling and analysis time, and a safety working load was verified to be predicted by reducing the thickness of the doubling pad by 85%. The results of the effects of various parameters reviewed in the study are expected to be used as good reference data for the lug design and safe working load prediction.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06c
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• pp.205-208
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• 1998

본 논문에서는 VLSI 기술에 바탕을 둔 top-down 접근 방식에 의하여 MPEG-2 오디오 부호화 알고리듬을 구현하였다. MPEG-2 오디오 부호화기의 알고리듬은 많은 연산량을 갖고 이질적인 특성을 갖고 이질적인 특성을 갖는 알고리듬들이 복합적으로 존재한다. 그러므로, 부호화기를 효과적으로 구현하기 위해서는 알고리듬 수준에서 구조적 수준에 이르기까지 많은 고찰이 이루어져야 한다. 본 논문에서는 우선 전체 부호화 알고리듬을 분석하여 이들을 다시 작업이라고 정의된 작은 부-알고리듬으로 나누었다. 다음으로, 분할된 작업들은 시간과 공간을 초대한 활용할 수 있도록 적절한 작업 순서를 부여하고, 좀 더 큰 모듈들로 모으는 클러스터링을 수행하였다. 마지막으로 이러한 분석 결과를 바탕으로, 실시간으로 동작하는 5.1 채널 MPEG-2 오디오 부호화기를 설계하였다. 설계된 시스템은 두 개의 하드웨어 블록과 한 개의 ASIP형 DSP 프로세서를 갖는 이질적인 다중 프로세서의 형태를 갖는다. 설계된 오디오 부호화기는 0.6$\mu\textrm{m}$ 표준 셀 기술을 이용하여 단일 칩으로 제작되었으며, PC에 탑재 가능한 시험 기판을 제작하여 동작을 검증하였다.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.430-434
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• 2004

본 논문에서는 관전류 직접제어 방식을 채택한 3.2kW(80kV,40mA)급 최소형, 최경량 Portable X-선 장치를 제안한다 본 장치는 X-선 발생을 위한 고전압 발생 단에 모노탱크 블록 사용하였고, 고주파 고전압용 인버터에는 스위칭 전력소자로서 Mini block type의 MOS-FET를 채용, 80kHz로 스위칭 함으로서 고전압 변압기를 비롯한 고전압 발생부의 크기와 무게를 최소화하였다. X-ray Power의 출력이 높아짐에 따라, X-ray tube의 필라멘트 인버터의 출력용량 또한 증가되었다. 본 논문에서는 설정 관전류에 대한 정밀한 제어를 위하여 2단계 모드로 필라멘트 예열을 행하여 관전류 응답특성을 개선하였으며 제안한 휴대용 X-선 발생장치의 부하변동에 따른 X-선 관전압과 관전류의 개선된 특징을 실험파형을 통하여 입증하였다.

• Korean Journal of Computational Design and Engineering
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• v.14 no.2
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• pp.69-76
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• 2009

The development of a simulation system requires many sub modules such as a dynamic module, a visualization module, etc. If a different freeware is used for each sub modules, it is hard to develop the simulation system by incorporating them because they use their own data structures. To solve this problem, a high-level data structure, called Dynamics Scene Graph Data structure (DSGD) is proposed, by wrapping data structures of two freeware; an Open Dynamics Engine (ODE) for the dynamic module and an Open Scene Graph (OSG) for the visualization module. Finally, to evaluate the applicability of the proposed data structure, it is applied to the block erection simulation in shipbuilding. The result shows that it can be used for developing the simulation system.