• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.7
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• pp.730-736
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• 2013

Time-domain clutter generation model for airborne pulse doppler phase-array radar is presented. Time-domain surface clutter signal is generated assuming earth of a sphere and considering geometry of a clutter patch, and generation of sub-array clutter signal is presented. The generated sub-array clutter signal can be used by simulation input signal in various radar applications of DBF(Digital Beamforming), ABF(Adaptive Beamforming), Stap(Space-Time Adaptive Processing) and etc.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.8 no.2
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• pp.57-63
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• 2009

The demand of digital broadcasting via networks has increased slowly in spite of the development of bidirectional broadcasting service technology and the effort of revitalization are actively performed nowadays. There are some reasons that the content differentiation is necessary. First, bidirectional digital broadcasting has no special content that attracts public attention. Second, bidirectional video content such as UCC is expected to revitalize economy due to simplification of authoring tool and user's desire to communicate interactively. So this paper proposes the data broadcasting sub-content architecture model by scenario using original data broadcasting content. At the same time, we design the content object metadata schema from the analysis of original data broadcasting content. It is restricted by 25 metadata in order to make it more smoothly working contents under the ubiquitous environment. This proposal is expected to affect the revitalization of content development and find out new sub-content model by rework original content.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.6
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• pp.136-142
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• 1994

This study presents an algorithm and related techniques which could satisfy the important properties of check weighers and conveyor scales. The algorithm of Recursive Least Squares Regression is described for te weighing system simulated as a dynamic model of the second order. Using the model and the algorithm, model parameters and then the mass being weighed can be determined from the step input. The performance of the algorithm is illustrated in digital simulation. Discussions are extended to the development of fast converging algorithm. It turns out that the algorithm shows several desirable features suitable for microcomputer assisted real-time signal processing, which are high precision and stability in noisy environment.

• Clean Technology
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• v.28 no.1
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• pp.63-78
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• 2022

Electronics industrial wastewater treatment facilities release organic wastewaters containing high concentrations of organic pollutants and more than 20 toxic non-biodegradable pollutants. One of the major challenges of the fourth industrial revolution era for the electronics industry is how to treat electronics industrial wastewater efficiently. Therefore, it is necessary to develop an electronics industrial wastewater modeling technique that can evaluate the removal efficiency of organic pollutants, such as chemical oxygen demand (COD), total nitrogen (TN), total phosphorous (TP), and tetramethylammonium hydroxide (TMAH), by digital twinning an electronics industrial organic wastewater treatment facility in a cyber physical system (CPS). In this study, an electronics industrial wastewater activated sludge model (e-ASM) was developed based on the theoretical reaction rates for the removal mechanisms of electronics industrial wastewater considering the growth and decay of micro-organisms. The developed e-ASM can model complex biological removal mechanisms, such as the inhibition of nitrification micro-organisms by non-biodegradable organic pollutants including TMAH, as well as the oxidation, nitrification, and denitrification processes. The proposed e-ASM can be implemented as a Water Digital Twin for real electronics industrial wastewater treatment systems and be utilized for process modeling, effluent quality prediction, process selection, and design efficiency across varying influent characteristics on a CPS.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.238-242
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• 2007

Today's commercial high resolution satellite imagery such as that provided by IKONOS and QuickBird, offers the potential to extract useful spatial information for geographical database construction and GIS applications. Digital maps supply the most generally used GIS data probiding topography, road, and building information. Currently, the building information provided by digital maps is incompletely constructed for GIS applications due to planar position error and warped shape. We focus on extracting of the accurate building information including position, shape, and height to update the building information of the digital maps and GIS database. In this paper, we propose a new method of 3D building information extraction with a single high resolution satellite image and digital map. Co-registration between the QuickBird image and the 1:1,000 digital maps was carried out automatically using the RPC adjustment model and the building layer of the digital map was projected onto the image. The building roof boundaries were detected using the building layer from the digital map based on the satellite azimuth. The building shape could be modified using a snake algorithm. Then we measured the building height and traced the building bottom automatically using triangular vector structure (TVS) hypothesis. In order to evaluate the proposed method, we estimated accuracy of the extracted building information using LiDAR DSM.

• The Journal of Engineering Geology
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• v.32 no.4
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• pp.449-466
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• 2022

The establishment of a complete geological model that includes information about all the various components at a site (such as underground structures and the compositions of rock and soil underground space) is difficult, and geological modeling is a developing field. This study uses commercial software for the relatively easy composition of geological models. Our digital modeling process integrates a model of Jeju Island's 3D geological information, models of cave shapes, and information on the state of a road at the site's upper surface. Among the numerous natural caves that exist in Jeju Island, we studied the Jaeamcheon lava tube near Hallim town, and the selected site lies below a road. We developed a digital model by applying the principles of building information modeling (BIM) to the cave (CaveBIM). The digital model was compiled through gathering and integrating specific data: relevant processes include modeling the cave's shape using a laser scanner, 3D geological modeling using geological information and geophysical exploration data, and modeling the surrounding area using drones. This study developed a global-scale model of the Hallim region and a local-scale model of the Jaeamcheon cave. Cross-validation was performed when constructing the LSM, and the results were compared and analyzed.

• Journal of Advanced Marine Engineering and Technology
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• v.20 no.4
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• pp.20-26
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• 1996

Recently, for the speed control of a diesel engine, some methods using the modern control theory such as LQ control technique, or $\textit{H}_{\infty}$control theory etc., have been reported. However, most of speed controlers of a diesel engine ever developed are still using the PID control algorithm. And, as another approach to the speed control of a diesel engine, the authors proposed already a new method to adjust the parameters of the PID controller by a model matching method. In the previous paper, the authors confirmed that the proposed new method is superior to Ziegler & Nichols's method through the analysis of results of the digital simulations under the assumption that the parameters of a diesel engine are known exactly. But, actually, it is very difficult to find out the value of parameters of a diesel engine accurately. And the parameters of a diesel engine are changigng according to the operating condition of a diesel engine. So, in this paper, a method to estimate the parameters of the PID controller for the speed control of a diesel engine by means of the model matching method are proposed. Also, the digital simulations are carried out in cases either with or without measurement noise. And this paper confirms that the proposed method here is superior to Ziegler & Nichols's method through the analysis of the characteristics of indicial responses.

• Journal of the Korean Institute of Landscape Architecture
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• v.17 no.3
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• pp.1-8
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• 1990

The digital terrain model (DTM) or digital elevation model (DEM) is commonly used in representing the continuous variation of relief over space. One of the most frequent applications is to display the three dimensional view of the landform concerned. In this paper, the altitude matrices-regular grid cell format of the elevation in Mt. Kyeryong National Park were used in developing the three dimensional view software for the first time in Korea. It required the removal of hidden lines or surfaces. To do this, it was necessary to identify those surfaces and line segments that are visible and those that are invisible. Then, only the visible portions of the landform were displayed. The assumption that line segments are used to approximate contour surfaces by polygons was used in developing the three dimensional orthographic view. In order to remove hidden lines, the visibility test and masking algorithms were used. The software was developed in the engineering workstation, SUN 3/280 at the Institute of Space Science and Astronomy using 'C' in UNIX operating system. The software developed in this paper can be used in various fields. Some of them are as follows : (1) Landscape design and planning for identifying viewshed area(line of sight maps) (2) For planning the route selection and the facility location (3) Flight simulation for pilot training (4) Other landscape planning or civil engineering purposes

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.2
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• pp.63-70
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• 2019

Electric transmission towers are facilities to transport electrical power from a plant to an electrical substation. The towers are connected using wires considering the wire tension and the clearance from the ground or nearby objects. The wires are installed on a rights-of-way that is a strip of land used by electrical utilities to maintain the transmission line facilities. Trees and plants around transmission lines must be managed to keep the operation of these lines safe and reliable. This study proposed the use of a low-cost drone photogrammetry for the transmission line rights-of-way mapping. Aerial photogrammetry is carried out to generate a dense point cloud around the transmission lines from which a DSM (Digital Surface Model) and DTM (Digital Terrain Model) are created. The lines and nearby objects are separated using nDSM (normalized Digital Surface Model) and the noises are suppressed in the multiple image space for the geospatial analysis. The experimental result with drone images over two spans of transmission lines on a mountain area showed that the proposed method successfully generate the rights-of-way map with hazard nearby objects.

• 전자공학회논문지 IE
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• v.48 no.1
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• pp.36-44
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• 2011

The purpose of this study was to develop the basic design principles for the engineering mathematics teaching model that supported college students to become collaborative problem solvers. For this purpose, the following four design principles were drawn from the steps of systems approach, especially with consideration of needs of engineering students, professors, curriculum and relevant research on mathematical education. As a result, the four design principles for the engineeering mathematics teaching model were drawn as follows: (1) Improve students' basic mathematical learning abilities through repetition and elaborative practice of the basic mathematical concepts and principles, (2) Develop students' problem solving abilities through collaborative projects or learning activities with peers, (3) Facilitate students' reflection and provide teacher's monitoring and prompt feedback during their learning process, and (4) Build up online learning environments that enable students to become self-regulated learners.