• Journal of Korea Water Resources Association
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• v.45 no.6
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• pp.545-555
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• 2012

A numerical modeling has become increasingly popular and more important to the study of water waves with a rapid advancement of computer technology. However, different types of problems are induced during simulating wave motion. One of the key problems is re-reflection to a computation domain at the incident boundary. The internal wave generating-absorbing boundary conditions have been commonly used in numerical wave models to prevent re-reflection. For the Navier-Stokes equations model, the internal wave maker using a mass source function of the continuity equation has been used to generate various types of waves. Nonetheless, almost every numerical experiment is performed in two dimensions and only a few tests have been expanded to three dimensions. More recently, a momentum source function of the Boussinesq equations is applied to generate essentially directional waves in the three dimensional Navier-Stokes equations model. In this study, the internal wave maker using a momentum source function is employed to generate targeted linear waves in the three-dimensional LES model.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.2285-2290
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• 2012

This study is about atherosclerosis which occupies the highest rate in many diseases people have and we have studied about atherosclerosis for abdominal aorta. Atherosclerosis is the phenomenon which blood vessel gets narrower, harder and thicker due to the stenosis of colesterol in blood vessel. If it becomes worse, arteries will be hard and blood can't flow smoothly, and even it can reach to death. In this study, the geometric models of the considered stenotic blood flow are two different types of constriction of cross-sectional area of blood vessel; 20 and 45% of constriction in each elastic wall and rigid wall. We have modeled by using finite element method to observe the changes of velocity and pressure. In case of the diameter of blood vessel decreased 45% in elastic wall model, the values of velocity and pressure were higher than the case of 20% and in case of the diameter of blood vessel decreased 45% in rigid wall model, the values of velocity and pressure were higher than the case of 20%. In cases of elastic wall models of the diameters of blood vessels decreased each of 20% and 45%, recirculation zones appeared. This results show understanding of hemodynamic properties depending on stenosed blood vessels.

• Journal of KIISE:Computing Practices and Letters
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• v.7 no.5
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• pp.510-521
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• 2001

Image retrieval system should be construct for searching fast, efficient image be extract the accurate feature information of image with more massive and more complex characteristics. Image retrieval system are essential differences between image databases and traditional databases. These differences lead to interesting new issues in searching of image, data modeling. So, cause us to consider new generation method of database, efficient retrieval method of image. In this paper, To extract feature information of edge using in searching from input image, we was performed to extract the edge by convolution Laplacian mask and input image, and we implemented the annotation-based and content-based image retrieval system for searching fast, efficient image by generation image database from extracting feature information of edge and metadata. We can improve the performance of the image contents retrieval, because the annotation-based and content-based image retrieval system is using image index which is made up of the content-based edge feature extract information represented in the low level of image and annotation-based edge feature information represented in the high level of image. As a conclusion, image retrieval system proposed in this paper is possible the accurate management of the accumulated information for the image contents and the information sharing and reuse of image because the proposed method do construct the image database by metadata.

• Journal of Internet Computing and Services
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• v.20 no.6
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• pp.85-93
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• 2019

Computational Science and Engineering is a convergence study that understands and solves complex problems such as science, engineering, and social phenomena through modeling using computing resources. Computational science and engineering combines algorithms, computational and informatics, and infrastructure. The importance of computational science is increasing with the improvement of computer performance and the development of large data processing technology. In Korea, Korea Institute of Science and Technology Information (KISTI) has been developing national computational science engineering software and utilization technology by combining basic science and computing technology through EDISON project. The EDISON project builds an open EDISON platform and integrates and services information systems in seven areas of computational science and engineering (computational thermal fluids, nanophysics, computational chemistry, structural dynamics, computational design, and computational medicine). Using this, we have established a web-based curriculum to lay the groundwork for fostering scientific talent and commercializing computational science and engineering software. The purpose of this study is to derive the quality characteristic factors of computational science platform and to empirically examine the effect on user satisfaction. This paper examines how the quality characteristics of information systems, the computational science engineering platform, affect the user satisfaction by modifying the research questions according to the propensity of the computational science platform by referring to the success factors of DeLone and McLean's information system. Based on the results of this study, we will suggest strategic implications for platform improvement by searching the priority of quality characteristics of computational science platform.

• The Journal of the Korea Contents Association
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• v.10 no.10
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• pp.54-67
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• 2010

Applying the conventional machine-learning method which has been frequently used in health-care area has several fundamental problems for modern U-health service analysis. First of all, we are still lack of application examples of the traditional method for our modern U-health environment because of its short term history of U-health study. Second, it is difficult to apply the machine-learning method to our U-health service environment which requires real-time management of disease because the method spends a lot of time in the process of learning. Third, we cannot implement a personalized U-health diagnosis system using the conventional method because there is no way to assign weights on the disease-related variables although various kinds of machine-learning schemes have been proposed. In this paper, a novel diagnosis scheme PCADP is proposed to overcome the problems mentioned above. PCADP scheme is a personalized diagnosis method and it makes the bio-data analysis just a 'process' in the U-health service system. In addition, we offer a semantics modeling of the U-health ontology framework in order to describe U-health data and service specifications as meaningful representations based on this PCADP. The PCADP scheme is a kind of statistical diagnosis method which has characteristics of flexible structure, real-time processing, continuous improvement, and easy monitoring of decision process. Upto the best of authors' knowledge, the PCADP scheme and ontology framework proposed in this paper reveals one of the best characteristics of flexible structure, real-time processing, continuous improvement, and easy monitoring among recently developed U-health schemes.

• Journal of the Institute of Convergence Signal Processing
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• v.11 no.2
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• pp.177-182
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• 2010

The flow of a universal system-level design methodology consists of system specification, system-level hardware/software partitioning, co-design, co-verification using virtual or physical prototype, and system integration. In the developing process of a hardware component in system, the design phase has been regarded as a phase consuming lots of time and cost. However, the verification phase in which functionality of the designed component is verified has recently been considered as a much important phase. In this paper, the implementation of a verification environment which is based on SystemC infrastructure and verifies the functionality of a hardware component is described. The proposed verification system uses SystemC user-defined channel as communication interface between variables of SystemC module and registers of Verilog module. The functional verification of an UART is performed on the proposed verification system. SystemC provides class library for hardware modeling and has an advantage of being able to design a system consisting hardware and software in higher abstraction level than register transfer level. Source codes of SystemC modules are reusable with a minor adaptation on verifying functionality of another hardware component.

• Korean Journal of Agricultural and Forest Meteorology
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• v.6 no.3
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• pp.170-176
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• 2004

This study was carried out to establish a spatial decision support system for evaluating climatic aspects of a given geographic location in complex terrains with respect to the quality apple production. Monthly climate data from S6 synoptic stations across South Korea were collected for 1971-2000. A digital elevation model (DEM) with a 10-m cell spacing was used to spatially interpolate daily maximum and minimum temperatures based on relevant topoclimatological models applied to Jangsoo county in Korea. For daily minimum temperature, a spatial interpolation scheme accommodating the potential influences of cold air accumulation and the temperature inversion was used. For daily maximum temperature estimation, a spatial interpolation model loaded with the overheating index was used. Freezing risk in January was estimated under the recurrence intervals of 30 years. Frost risk at bud-burst and blossom was also estimated. Fruit quality was evaluated for soluble solids, anthocyanin content, Hunter L and A values, and LID ratio, which were expressed as empirical functions of temperature based on long-term field observations. AU themes were prepared as ArcGlS Grids with a 10-m cell spacing. Analysis showed that 11 percent of the whole land area of Jangsoo county might be suitable for quality 'Fuji' apple production. A computer program (MAPLE) was written to help utilize the results in decision-making for site-selection of new orchards in this region.

• Journal of Astronomy and Space Sciences
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• v.29 no.2
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• pp.233-244
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• 2012

The Korea Astronomy and Space Science Institute and the Department of Astronomy at the University of Texas at Austin are developing a near infrared wide-band high resolution spectrograph, immersion grating infrared spectrometer (IGRINS). The compact white-pupil design of the instrument optics uses seven cryogenic mirrors, including three aspherical off-axis collimators and four flat fold mirrors. In this study, we introduce the optomechanical mount designs of three off-axis collimating mirrors and one flat slit-viewer fold mirror. Two of the off-axis collimators are serving as H and K-band pupil transfer mirrors, and are designed as system alignment compensators in combination with the H2RG focal plane array detectors in each channel. For this reason, the mount designs include tip-tilt and parallel translation adjustment mechanisms to properly perform the precision alignment function. This means that the off-axis mirrors' optomechanical mount designs are among the most sensitive tasks in all IGRINS system hardware. The other flat fold mirror is designed within its very limitedly allowed work space. This slit-viewer fold mirror is mounted with its own version of the six-point kinematic optics mount. The design work consists of a computer-aided 3D modeling and finite element analysis (FEA) technique to optimize the structural stability and the thermal behavior of the mount models. From the structural and thermal FEA studies, we conclude that the four IGRINS mirror mounts are well designed to meet all optical stability tolerances and system thermal requirements.

• Journal of Digital Convergence
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• v.15 no.12
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• pp.323-331
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• 2017

In this paper, four types of deposition control processes such as temperature, pressure, input/output(I/O), and gas were replaced by the Internet of Things(IoT) to analyze the data load and sequence procedure before and after the application of it. Through this analysis, we designed the load balancing in the sensing area of the deposition process by creating the sequence diagram of the deposition process. In order to do this, we were modeling of the sensor I/O according to the arrival process and derived the result of measuring the load of CPU and memory. As a result, it was confirmed that the reliability on the deposition processes were improved through performing some functions of the equipment controllers by the IoT. As confirmed through this paper, by applying the IoT to the deposition process, it is expected that the stability of the equipment will be improved by minimizing the load on the equipment controller even when the equipment is expanded.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.9
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• pp.756-761
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• 2016

The objective of this study is to design and manufacture a fuel pump with the plunger diameter of 4 mm and stroke of 7 mm that can be mounted in a small single-cylinder four-stroke agricultural diesel engine, and to investigate the performance characteristics of the pump. The combustion pressure in a cylinder was reproduced by forming the back pressure of 1, 6, 11, 16 and 21 bar with a nitrogen gas in the home-manufactured modeling cylinder. In the experiment, the discharge pressure was measured at the spot of 1 cm away from the discharge port of a developed fuel pump. The delivery pressure and delivery flow rate were measured at the spot of 30 cm away from the discharge port of the pump, and the pump efficiency was calculated. The pump motor speed was changed from 600 to 800, 1000, 1200 and 1400 rpm. It is found that the delivery feed rate of fuel pump is increased as the rotational speed is raised, and is decreased as the back pressure, compression pressure in the cylinder, is increased. Also, the pump efficiency is reduced as the rotational speed and back pressure are increased.