• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.6 s.261
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• pp.635-643
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• 2007

As many engineers and technicians are involved in the design process of large scale and/or complex products, there are a lot of miss matches and interferences due to designers' faults and several kinds of CAD systems. Recently, CAD systems are applied to verify and check the assembly process. Digital Mock-Up(DMU) system, a tool to build a virtual mock-up in the design stage, has been used to prevent the interferences and miss matches during precision design processes. Using the virtual assembly tool, engineers are able to design precision and interference free parts without physical mock-ups. Instead of a single CAD source, several CAD systems are used to design a complex product. Several organizations are involved in the distributed design environment for heterogeneous multi-CAD assembly. XML and the lightweight CAD file are proposed for the multi-CAD assembly. XML data contains hierarchy of the heterogenenous multi-CAD assembly. STEP PDM schema and STEP ISO 10303-28 formations are applied to construct the XML data. The lightweight CAD file produced from various CAD files through ACIS kernel and InterOp not only contains mesn, B-Rep and topological data, but also is used to visualize CAD data and to verify dimensions. Developed system is executed on the desktop computers. It does not require commercial CAD systems to visualize 3D assembly data. Real-time interference and fitness checks, dimensional verification, and design and assembly verification are performed on the developed system. Assembly of heterogeneous models for a car is conducted to verify the effectiveness of the developed DMU system on the Internet.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.2
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• pp.126-136
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• 2020

Recently, unmanned aerial vehicles (UAV, Drone) are highly regarded for their potential in the agricultural field, and research and development are actively conducted for various purposes. Therefore, in this study, to present a framework for tracking research trends in UAV use in the agricultural field, we secured a keyword search strategy and analyzed social network, a methodology used to analyze recent research trends or technological trends as an analysis model applied. This study consists of three stages. As a first step in data acquisition, search terms and search formulas were developed for experts in accordance with the Keyword Search Strategy. Data collection was conducted based on completed search terms and search expressions. As a second step, frequency analysis was conducted by country, academic field, and journal based on the number of thesis presentations. Finally, social network analysis was performed. The analysis used the open source programming language 'Python'. Thanks to the efficiency and convenience of unmanned aerial vehicles, this field is growing rapidly and China and the United States are leading global research. Korea ranked 18th, and bold investment in this field is needed to advance agriculture. The results of this study's analysis could be used as important information in government policy making.

• Journal of Digital Convergence
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• v.15 no.7
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• pp.55-64
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• 2017

The purpose of this study is to identify the difficulties of learners who started programming after entering college and to search an effective software education method as university liber arts for non-science major students. In order to do this, we analyzed the difficulties of learners in Python programming classes composed of students from various majors at H University through questioning and taught them using flipped class model with pre-questions. The questions that students submit are collected online before class every time, the data on the degree of the difficulty of feeling and the understanding of feeling were obtained through the questionnaire. As a result, for learners who are new to programming, the learners should allocate the process of making the problem into a logical abstraction at the beginning of the curriculum before learning the basic concept of computer language, each lesson should be practiced through the bottom-up problems enough to provide a logical understanding before actual coding. In addition, detailed curriculum should be developed according to characteristics of learner's major, contents and conducting level.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.123-130
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• 2002

A general formulation for shape design sensitivity analysis over three dimensional beam structure is developed based on a variational formulation of the beam in linear elasticity. Sensitivity formula is derived based on variational equations in cartesian coordinates using the material derivative concept and adjoint variable method for the displacement and Von-Mises stress functionals. Shape variation is considered for the beam shape in general 3-dimensional direction as well as for the orientation angle of the beam cross section. In the sensitivity expression, the end points evaluation at each beam segment is added to the integral formula, which are summed over the entire structure. The sensitivity formula can be evaluated with generality and ease even by employing piecewise linear design velocity field despite the bending model is fourth order differential equation. For the numerical implementation, commercial software ANSYS is used as analysis tool for the primal and adjoint analysis. Once the design variable set is defined using ANSYS language, shape and orientation variation vector at each node is generated by making finite difference to the shape with respect to each design parameter, and is used for the computation of sensitivity formula. Several numerical examples are taken to show the advantage of the method, in which the accuracy of the sensitivity is evaluated. The results are found excellent even by employing a simple linear function for the design velocity evaluation. Shape optimization is carried out for the geometric design of an archgrid and tilted bridge, which is to minimize maximum stress over the structure while maintaining constant weight. In conclusion, the proposed formulation is a useful and easy tool in finding optimum shape in a variety of the spatial frame structures.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.22 no.3
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• pp.303-309
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• 2004

In this paper, an adaptive Bayesian approach to image segmentation was developed for boundary detection. Both image intensities and texture information were used for obtaining better quality of the image segmentation by using the C programming language. Fuzzy c-mean clustering was applied fer the conditional probability density function, and Gibbs random field model was used for the prior probability density function. To simply test the algorithm, a synthetic image (256$\times$256) with a set of low gray values (50, 100, 150 and 200) was created and normalized between 0 and 1 n double precision. Results have been presented that demonstrate the effectiveness of the algorithm in segmenting the synthetic image, resulting in more than 99% accuracy when noise characteristics are correctly modeled. The algorithm was applied to the Antarctic mosaic that was generated using 1963 Declassified Intelligence Satellite Photographs. The accuracy of the resulting vector map was estimated about 300-m.

• The KIPS Transactions:PartD
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• v.15D no.1
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• pp.147-154
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• 2008

Along with the trend of internet use, various web application developments have been performed to provide information that was managed in the internal database on the web by making a web server page. However, in most cases, a direct program was made without a systematic developmental methodology or with the application of a huge developmental methodology that is inappropriate and decreased the efficiency of the development. A web application that fails to follow a systematic developmental methodology and uses a script language can decrease the productivity of the program development, maintenance, and reuse. In this thesis, the auto writing tool for a dynamic web server page was designed and established by using a database for web application development based on a fast and effective script. It suggests a regularized script model and makes a standardized script for the data bound control tag creator by analyzing a dynamic web server page pattern with the database in order to contribute to productivity by being used in the web application development and maintenance.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.5
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• pp.341-346
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• 2013

In this paper, we propose a rule extraction method using a modified Fuzzy Min-Max (FMM) neural network. The suggested method supplements the hyperbox definition with a frequency factor of feature values in the learning data set. We have defined a relevance factor between features and pattern classes. The proposed model can solve the ambiguity problem without using the overlapping test process and the contraction process. The hyperbox membership function based on the fuzzy partitions is defined for each dimension of a pattern class. The weight values are trained by the feature range and the frequency of feature values. The excitatory features and the inhibitory features can be classified by the proposed method and they can be used for the rule generation process. From the experiments of sign language recognition, the proposed method is evaluated empirically.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.1
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• pp.46-54
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• 2008

In this paper, a low-cost impedance spectroscopy system(LCISS) suitable for modeling the electrochemical power sources such as fuel cells, batteries and supercapacitors is designed and implemented. Since the developed LCISS is composed of simple sensor circuits, commercial data acquisition board and LabVIEW software, a graphic language with powerful HMI(Human-Machine Interface), it is expected ta be widely used in substitution of the expensive EIS instruments. In the proposed system, the digital lock-in amplifier is adopted to achieve the accurate measurements even in the presence of the high level of noises. The developed hardware and software is applied to measure the impedance spectrum of the Ballard Nexa 1.2kW proton exchange membrane fuel cell stack and an equivalent impedance model is proposed based on the measurement results. The validity of the proposed equivalent circuit and the developed system is proven by the measurement of the ac power losses of the PEM fuel celt stack by the ripple current.

• The KIPS Transactions:PartD
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• v.8D no.6
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• pp.789-798
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• 2001

ITS (Intelligent Transport Systems) is comprised of a number of advanced technologies, including information processing, communications, control, and electronics. Joining these technologies to the transportation system will save lives more safely, save time, and save money more efficiently. The National ITS Architecture provides a common framework for planning, defining, and integrating intelligent transportation systems. Most ITS projects are being designed and implemented in accordance with the National ITS Architecture, a reference framework that spans all of standards activities. Recently, as software technology is rapidly improved and stabilized, there are some needs to reuse pre-developed and powerful ITS technology. ITS standardization based on components and open interfaces becomes a way to solve these reusability of current ITS technology. This paper focuses on how could we design and implement the ITS component based on the National ITS Architecture. Furthermore, design and analysis of UML (Unified Modeling Language) was made through the ATIS (Advanced Traveller Information System) component development task and this UML methodology is expected to provide a standardized model for newly developed ITS components.

• Journal of the Korean association of regional geographers
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• v.4 no.2
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• pp.139-150
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• 1998

Recently in connection with the development of network technology, GIS researches shift their focuses to openGIS which enables to share heterogeneous geodata and geoprocessing resource under the environment of LAN and WAN. This study proposes an easy method to develope GUIs which enables openGIS in the intranet environment. In the developing stage of GUI, the most important thing is to develop effective windows programming technique and apply a internet linking technique to developed GUIs. This study shows an internet linking technique and a GUI developing method using OLE automation and ActiveX/COM standards. Using a case study of Taegu City Library, the study constructs a GIS database and develops its GUI which performs map overlaying, referencing attribute tables, drawing up of thematic map, buffer analysis, and statistical calculations. This study remains same further research areas of developing a new advanced technique for openGIS and its GUI using distributed object model of CORBA, Java language, and JDBC data accessing technique.