• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.255-258
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• 2001

In this paper, DC and small signal characteristics with different physical parameters are expected for p-HEMTs (Pseudomorphic High Electron Mobility Transistors) with different temperatures ranging from 300K to 623K which are widely used for a low noise and/or ultra high frequency device. A device of 0.2$\times$200 ${\mu}{\textrm}{m}$$^2$dimension having very low noise has been chosen to extract the experimental data. Theoretical prediction has been obtained using a simulaor(HELENA) which needs experimental input data extracted from reverse engineering process. From the results, relation between structural parameters and temperature dependency of electrical characteristics are qualitatively explained to use in the design of descrete and integrated circuits to guarantee the optimal operation of the system.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.4 no.3
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• pp.51-56
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• 2005

This research presents a modeling and a manufacturing method of screw flow meter. This paper introduces the efficient design and manufacturing method of screw type flow meter using reverse engineering and test technology. The methods introduced this paper utilize the reverse engineering that is increasing accuracy of modeling and manufacturing of reverse model. And then it can be used in performance test with hydraulic test equipment. Hence this can be used in the basic document for development of the quite accurate flowmeter.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.841-845
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• 1996

Reverse engineering enables a fast creation of CAD model from an existing part without any technical drawing or digital data. This method of data acquisition is necessary in several industrial applications when the modification of an existing product design has to be performed and verified afterwards. In this paper, the surface of an existing ship propeller was measured by a tactile measuring system and the acquired point data of the surface were used for modeling of a solid model in CAD system. By using LOM and casting processes, an aluminum propeller for functional test was manufactured and then its accuracy was measured by a laser scanner and compared with the origin릴 CAD data. As the results show, the use of LOM as a rapid prototyping process and casting as a secondary process delivers a functional prototype propeller which can be used for test purposes.

• Korean Journal of Computational Design and Engineering
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• v.14 no.1
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• pp.33-41
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• 2009

Triangular mesh models are widely used in reverse engineering, computer graphics, rapid prototyping and NC(numerical controller) tool-path generation. Triangular mesh models are generated from point clouds, surface models and solid models. A halfedge-based triangular mesh data structure is proposed and the development considerations are presented. In the presented data structure, halfedge is the key data structure. Halfedge stores its triangle index and the order in the triangle. Triangles do not store the halfedge lists explicitly. Halfedge is referred by value and defined when it is required. Proposed data structure supports four design requirements: efficient rendering, compact memory, supporting efficient algorithms and easy programming.

• Advances in aircraft and spacecraft science
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• v.8 no.4
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• pp.331-344
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• 2021

Airframe internal and external specifications are the product of intensive intellectual efforts and technological breakthroughs distinguishing each aircraft manufacturer. Therefore, geometrical information characterizing aircraft primary aerodynamic surfaces remain classified. When attempting to model real aircraft, many members of the aeronautical community depend on their personal expertise and generic design principles to bypass the confidentiality obstacles and sketch real aircraft airfoils, which therefore vary for the same aircraft due to the different designers' initial assumptions. This paper presents a photogrammetric shape prediction method for deriving geometrical properties of real aircraft airframe by utilizing their publicly accessible static and dynamic visual content. The method is based on extracting the visually distinguishable curves at the fairing regions between aerodynamic surfaces and fuselage. Two case studies on B-29 and B-737 are presented showing how to approximate the sectional coordinates of their wing inboard airfoils and proving the good agreement between the geometrical and aerodynamic properties of the replicated airfoils to their original versions. Therefore, the paper provides a systematic reverse engineering approach that will enhance aircraft conceptual design and flight performance optimization studies.

• The KSFM Journal of Fluid Machinery
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• v.18 no.1
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• pp.20-28
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• 2015

The pump-turbine impeller is the key component of pumped storage power plant. Current design methods of pump-turbine impeller are private and protected from public viewing. Generally, the design proceeds in two steps: the initial hydraulic design and optimization design to achieve a balanced performance between pump mode and turbine mode. In this study, the 3D inverse design method is used for the initial hydraulic impeller design. However, due to the special demand of high performance in both pump and reverse mode, the design method is insufficient. This study is carried out by modifying the geometrical parameters of the blade which have great influence and need special consideration in obtaining the high performance on the both modes, such as blade shape type at low pressure side (inlet of pump mode, outlet of turbine mode) and the blade lean at blade high pressure side (outlet of pump mode, inlet of turbine mode). The influence of the geometrical parameters on the performance characteristic is evaluated by CFD analysis which presents the efficiency and internal flow results. After these investigations of the geometrical parameters, the criteria of designing pump-turbine impeller blade low and high sides shape is achieved.

• Proceedings of the KAIS Fall Conference
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• 2001.11a
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• pp.107-110
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• 2001

Design process is the essential technology for development of industry in nation, but contrary to its significance the trial for development of design technology is not so active because it requires a lot of time and efforts to educate design engineers. For that reason, most of enterprises concentrated their efforts for improving product technologies to get instant effects in short periods, and through these trials considerable results could be achieved. Recently, however, many people realized that industrial development through only product technology without design technology has limits, accordingly, a lot of efforts, to educate machine designers whom have enough knowledge and ability on design through advanced design technology, concentrated for industrial development. In general, the curriculum of conventional education for machine design in most universities is mainly compose of three subjects, the theory for elements design, geometric modeling practice for mating engineering drawings using CAD software, and analysis of elements using CAE software fur determining whether proposed solution is correct or rational. Furthermore, because these three subject are provided for students as the completely separated subjects, most of students who have educated with this method have no enough ability to Integrate all design process into a comprehensive whole process. This paper proposes a new design education methodology through reverse engineering that can overcome these problems of conventional education method.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.1
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• pp.89-96
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• 2015

Smart water grid is a water network with communication to save water and energy using various water resources. In smart water grid, water product from the various sources can be blended to be supplied to end-users. The product water blending was reported by literatures while feed water blending has been rarely reported so far. In this work, a commercial reverse osmosis (RO) system design software provided by a membrane manufacturer was used to elucidate the effect of feed water blending on the performance of seawater reverse osmosis (SWRO) plant. Fresh water from exisiting water resource was assumed to be blended to seawater to decrease salt concentration of the RO feed water. The feed water blending can simplify the RO system from double to single pass and decrease seawater intake amount, the unit prices of the RO system components including high pressure pump, and operation risk. Due to the increase in RO plant capacity with the feed water blending, however, the RO membrane area and total power consumption increase at higher water blending rates. Therefore, a specific benefit-cost analysis should be carried out to apply the feed water blending to SWRO plants.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.1
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• pp.7-14
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• 2017

This study carried out a numerical analysis of the effects of hot waste water supply on the performance of a Type II absorption heat pump. There are two types of hot waste water supply, regular series flow and reverse series flow. Also it investigated the interaction between each type of flow and heat exchange solutions. As the effectiveness of heat exchange solutions increase, the steam generation and (COP) increase as well. If the effectiveness of a heat exchange solution is lower than 0.566, the steam generation rate of the reverse flow is lower than that of the regular series flow. A high effectiveness of heat exchange solution is therefore required to make a larger amount of steam in reverse series flow than with ordinary series flow. The COP difference between the two types of flow decreases with the increasing effectiveness of the heat exchange solution. Thus, a reverse flow type absorption heat pump can match the high steam generation rate and COP of the ordinary flow type when a highly effective heat exchange solution is applied.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.1 s.94
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• pp.95-107
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• 1999

The design models of a new product in general are created using clay models or wooden mock-ups. The reverse engineering(RE) technology enables us to quickly create the CAD model of the new product by capturing the surface of the model using laser digitizers or coordinate measuring machines. Rapid prototyping (RP) is another technology that can reduce the product development time by fabricating the physical prototype of a part using a layered manufacturing technique. In reverse engineering process, however, the digitizer generates an enormous amount of point data, and it is time consuming and also inefficient to create surfaces out of these data. In addition, the surfacing operation takes a great deal of time and skill and becomes a bottleneck. In rapid prototyping, a faceted model called STL file has been the industry standard for providing the CAD input to RP machines. It approximates the CAD model of a part using many planar triangular patches and has drawbacks. A novel procedure that overcomes these problems and integrates RE with RP is proposed. Algorithms that drastically reduce the point clouds data have been developed. These methods will facilitate the use of reverse engineered geometric data for rapid prototyping, and thereby will contribute in reducing the product development time.