• 한국압력기기공학회 논문집
• /
• 제6권1호
• /
• pp.65-71
• /
• 2010

The plugging rate of reheater tubes of Wolsung unit 1 nuclear power plant has been increased by corrosion and erosion since 1990. As the dimensions of the new first stage reheater bundle tubes which were supplied by Hanjung company to replace were different from old one, numerical calculations are carried out for flow and heat transfer in the reheater bundle tubes of the N.P.P. Numerical calculations consists of thermal performance, drain line pressure drop, flow change by pressure drop of line, stress analysis of finned tubes and analysis of flow induced vibration. Computational analysis using heat transfer research institute program is adopted to verify the results of the numerical calculations. It contains the evalution of performance in the system with view to location of the new reheater bundle and it shows the differences between the numerical calculation results and heat transfer research institute program output.

• 로봇학회논문지
• /
• 제9권4호
• /
• pp.197-205
• /
• 2014

As computer vision algorithms are developed on a continuous basis, the visual information from vision sensors has been widely used in the context of simultaneous localization and mapping (SLAM), called visual SLAM, which utilizes relative motion information between images. This research addresses a visual SLAM framework for online localization and mapping in an unstructured seabed environment that can be applied to a low-cost unmanned underwater vehicle equipped with a single monocular camera as a major measurement sensor. Typically, an image motion model with a predefined dimensionality can be corrupted by errors due to the violation of the model assumptions, which may lead to performance degradation of the visual SLAM estimation. To deal with the erroneous image motion model, this study employs a local bundle optimization (LBO) scheme when a closed loop is detected. The results of comparison between visual SLAM estimation with LBO and the other case are presented to validate the effectiveness of the proposed methodology.

• Korean Journal of Geomatics
• /
• 제4권1호
• /
• pp.9-16
• /
• 2004

An object-oriented design was carried out for the digital photogrammetric processes. Classes were identified and implemented to develop an integrated digital photogrammetry system using a 3 dimensional self-calibration model for CCD cameras. This integrated system is deemed to be a significant progress from the conventional photogrammetric system which is a series of discrete processes. Object oriented methodology was selected for the implementation of the integrated photogrammetric system because it would be a very complex task to get the same result using a procedural programming language. Besides the simplification of development effort, object oriented methodology has further benefits of better management of program in case when updates to parts of the program are necessary. Using the classes designed in this study, a 3 dimensional self-calibration model was developed for a CCD camera. Classes for data input and image handling as well as classes for bundle adjustment were implemented. The bundle adjustment system was further enhanced with member functions to handle additional parameters for principal point coordinates and focal length, thereby, enabling the application to non-metric CCD cameras.

• 대한토목학회논문집
• /
• 제7권4호
• /
• pp.125-132
• /
• 1987

사진측량(寫眞測量)에서 이용되는 번들조정(調整)은 공선조건(共線條件)을 기초로 하며, 많은 비지형(非地形)분야에서 이용되고 있다. 그러나 비측량용(非測量用)사진기의 경우 지표(指標)가 없고 내부(內部) 및 외부표정요소(外部標定要素)의 초기근사값을 모르기 때문에, 이를 필요로 하는 번들조정(調整)에는 적용할 수 없다. 상좌표(像座標)로 부터 절대좌표(絶對座標)가 근사값을 요구하지 않고 직접변환되는 DLT(direct linear transformation) 프로그램이 Marzan과 Karara에 의해 개발되었다. 본(本) 논문(論文)에서는, 비측량용(非測量用)사진기에 의한 근거리사진측량(近距離寫眞測量)의 정확도(正確度)를 향상시키기 위해 DLT프로그램을 수정하였다. 수정된 프로그램에는 과대오차(過大誤差)의 검출(檢出) 및 외부표정요소(外部標定要素)의 계산과정을 포함시켰으며, 반복계산수를 증가시켰다.

• 한국자동차공학회논문집
• /
• 제15권2호
• /
• pp.87-94
• /
• 2007

It has been argued that the use of plastics can cause problems during design and manufacture owing to their low strength, relatively poor thermal conductivity and large thermal expansion. However, the advantages of plastics e.g., corrosion resistance, low cost, curtailment of weight, design flexibility etc., can compensate abundantly for the disadvantages. This study analyzes and compares the heat transfer performance characteristics of automotive compact oil cooler composed of plastic tube bundle with conventional metal oil cooler on the same core area basis as diameter, tube thickness, number of tube or tube arrangement varies. The performance analyses are accomplished by use of computational fluid dynamics program Fluent 6.2, which is verified and compared with the results of performance tests. The result of analyses is coincided with that of experiments. Flow pattern at air side according to tube arrangement is dominant factor which affects heat dissipation in case of similar total heat transfer surface area.

• 대한토목학회논문집
• /
• 제12권4_1호
• /
• pp.121-128
• /
• 1992

본 연구는 SPOT 위성영상에서 존재하는 정오차요소를 조정체계에 유의한 부가매개변수를 도입하여 보정하는 자체검정 광속조정의 알고리즘을 확립하고 SPOT 위성영상의 자료형태에 유의한 부가매개 변수항을 제시하는데 목적이 있다. 본 연구 결과, SPOT 위성영상용 자체검정 광속정법 알고리즘을 확립하고 프로그램을 개발하였으며, 부가매개변수의 결정력 검토 및 유의성검정을 통해 각 자료형태의 정오차 보정에 유의한 부가매개변수항을 결정할 수 있었다. 또한, 본 연구를 통해 확립된 SPOT 위성영상의 자체검정 광속조정 알고리즘은 위치결정의 정화도 향상에 유용함을 알 수 있었다.

• 한국산학기술학회논문지
• /
• 제17권6호
• /
• pp.18-25
• /
• 2016

대형 압축식 냉동기의 증발기 전열관으로는 그간 평활관이 주로 사용되어 왔으나 최근들어 비등 성능이 우수한 성형 가공관을 많이 사용하고 있다. 증발기는 관군으로 구성되고 따라서 증발기 내 위치에 따라 냉매 상태가 다르다. 특히 R-11, R-123과 같은 저압 냉매는 압력변화에 따른 포화온도 변화가 크므로 위치에 따라 포화온도가 다르게 된다. 따라서 증발기를 적절히 설계하려면 증발기 내 각 위치에서의 냉매의 상태를 적절히 예측하여야 한다. 본 연구에서는 대형 냉동기의 만액식 증발기를 모사할 수 있는 컴퓨터 프로그램을 개발하였다. 이 프로그램은 증발기를 미소 체적으로 구분하고 각 미소 체적에 적절한 관 내외측 열전달 및 압력손실 상관식을 적용하여 해석을 수행하였다. 본 프로그램을 R-123을 사용하는 T사의 만액식 증발기 해석에 적용한 결과 만족할 만한 결과를 얻었다. 이 프로그램을 이용하여 신 냉매인 R-123, R-134a를 사용하는 만액식 증발기의 해석을 수행하였고 특히 관군 세장비의 영향을 검토하였다.

• 한국소음진동공학회논문집
• /
• 제12권4호
• /
• pp.261-271
• /
• 2002

The fluid-elastic instability analysis of the U-tube bundle inside the steam generator is very important not only for detailed design stage of the SG but also for the change of operating condition of the nuclear powerplant. However the calculation procedure for the fluid-elastic instability was so complicated that the consolidated computer program has not been developed until now. In this study, the numerical calculation procedure and the computer program to obtain the stability ratio were developed. The thermal-hydraulic data in the region of secondary side of steam generator was obtained from executing the ATHOS3 code. The distribution of the fluid density can be calculated by using the void fraction, enthalpy, and operating pressure. The effective mass distribution along the U-tube was required to calculate natural frequency and dynamic mode shape using the ANSYS ver. 5.6 code. Finally, stability ratios for selected tubes of the CE type steam generator were computed. We considered the YGN 3.4 nuclear powerplant as the model plant, and stability ratios were investigated at the flow exit region of the U-tube. From our results, stability ratios at the central and the outside region of the tube bundle are much higher than those of other region.

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 1997년도 추계학술발표회논문집(1)
• /
• pp.152-157
• /
• 1997

To test the viability of CANFLEX-SEU bundles in an existing CANDU 6 reactor, core follow-up simulation has been carried out using the reactor fueling simulation program of the CANDU 6, RFSP computer code, and a lattice physics code, WIMS-AECL. During the core follow-up, bundle and channel powers and zone levels have been checked against their operating limits at each simulation. It is observed from the simulation results that an equilibrium core loaded with 0.9 w/o CANFLEX-SEU bundles could be refueled ,and maintained for 550 FPD without any significant violations in the channel and bundle power limits and the permissible operating range of the liquid zone controllers.

• 한국의류학회지
• /
• 제31권9_10
• /
• pp.1321-1332
• /
• 2007

The purposes of this research were to investigate the influences of shopping value, brand awareness, and the types of sales promotion on the purchase of bundled cosmetics. In experiment, 1) shopping value 2) brand awareness 3) types of sales promotion were manipulated as independent variables, and consumer preference and purchasing intention of bundle of cosmetics were measured as dependent variables. This research was an experimental design which was $2{\times}2{\times}2$ mixed factorial design. For the data analysis, factor analysis, cluster analysis, three-way ANOVA were used by utilizing SAS program. The main results of the study were summarized as follows: First, the results indicated that the consumer of hedonic shopping value have a positive effect on preferring price-cut sales, especially if brand awareness is high. Second, the consumer of utilitarian shopping value preferred price-cut sales to special offer, irrespective of brand awareness. This result indicates that consumers who gets more involved in and enjoys shopping are likely to have more brand awareness than others. This. seems to be the important characteristics of shopping. Consumer who have utilitarian shopping value concerned in price. The result showed the 3-way interaction effects on the consumer preference of bundle of cosmetics.