• Nuclear Engineering and Technology
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• v.27 no.1
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• pp.45-52
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• 1995

In influence of the vapor phase turbulent stress (i.e., the too-phase Reynolds stress) to the characteristics of two-phase system in a horizontal pipe has been theoretically investigated. The average two-fluid model has been constituted with closure relations for stratified flow in a horizontal pipe. A vapor phase turbulent stress model for the regular interface geometry has been included. It is found that the second order waves propagate in opposite direction with almost the same speed in the moving frame of reference of the liquid phase velocity. Using the well-posedness limit of the two-phase system, the dispersed-stratified How regime boundary has been modeled. Two-phase Froude number has been found to be a convenient parameter in quantifying the onset of slugging as a function of the global void fraction. The influence of the taper phase turbulent stress was found to stabilize the flow stratification.

• Journal of Digital Convergence
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• v.14 no.12
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• pp.471-476
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• 2016

Recently, important information related with smart work such as office and video conference are handled in smart device quite a lot compare with before. Also, execution environment of smart devices is getting developed as open software environment. It brought convenience to download and use any kind of application software. By that, security side of smart devices became vulnerable. This paper will discuss characteristics of smart device security technology based on virtualization that is a mobile device platform with isolated secure execution area based on TEE (Trusted Execution Environment). Also, this paper will suggest an implementation method about safe smart device security platform based on domain separation for application software which can be executed in smart devices. The domain separation based smart device security platform technology in this paper blocks unauthorized access and leakage of sensitive information in device. Also it will be the solution can block transmission and execution of malicious code in various area including variety of IoT devices in internet rather than just smart devices.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.1
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• pp.122-126
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• 2008

Integrating a 3D solid modeler with a general purpose FEM code, an automatic stress intensity factor analysis system of the 3D crack problems has been developed. A geometry model, i.e. a solid containing one or several 3D cracks is defined. Several distributions of local node density are chosen, and then automatically superposed on one another over the geometry model by using the fuzzy knowledge processing. Nodes are generated and quadratic tetrahedral solid elements are generated by the Delaunay triangulation techniques. Finally, the complete finite element(FE) model generated, and a stress analysis is performed. This paper describes the methodologies to realize such functions, and demonstrates the validity of the present system.

• Journal of IKEEE
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• v.15 no.4
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• pp.345-353
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• 2011

Recently portable mobile devices such as smart-phones and notebooks have rapidly increasing demands. Those devices consume more power because they are expected to offer more complex functionality including multimedia features. For these reasons engineering efforts are changing to focus on maximizing energy efficiency within a limited battery capacity instead of increasing computational performance. In this paper, we propose a battery management system using event driven programming technique on a embedded processor. We also show that the proposed system satisfies SBS (Smart Battery Specification) v1.1. The proposed system maintains minimum code size and memory size comparing to those of RTOSs. The proposed system can be also easily incorporated in the conventional RTOSs as a form of firmware.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.4
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• pp.791-797
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• 2001

In this paper, high-speed ,large-capacity ATM switching-chip is developed by MCM technology. MCM technology is suited for light-weight portable communications, mobile computing, high-frequency applications. For test of the developed MCM switching-chips, the simulating model is made by VHDL code of previously developed chip and input-output values of modeling pattern are obtained through the simulation. After the pattern values in chip-test machine are inserted , their results are compared with the simulation results. The design in this paper is simulated by synopsys design tool using SUN workstation and functions of chip is measured by TRILLIUM machine. Simulated and measured results have been compared, showing close agreement. Last, the MCM technique presented in this paper will provide useful insight into future designs.

• The Journal of Information Technology
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• v.6 no.1
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• pp.71-84
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• 2003

In this paper, it is presented the efficient system for data recognition using the proposed binary code images. The proposed algorithm finds the position of binary image. Through the process of the block region classification, it is classified each block with the edge region using the value of gray level only. Each block region is divided horizontal and vertical edge region. If horizontal edge region blocks are classified over six blocks in any region, the proposed algorithm should search the vertical edge region in the start point of the horizontal edge region. If vertical edge region blocks were found over ten blocks in vertical region, the code image would found. Practical code region is acquired from the rate of the total edge region that is computed from the binary image that is processed with the average value. In case of the wrong rate, it is restarted the code search in the point after start point and the total process is followed. It has a short time than the before process time because it had classified block information. The block processing is faster thant the total process. The proposed system acquires the image from the digital camera and makes binary image from the acquired image. Finally, the proposed system extracts various characters from the binary image.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.1
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• pp.65-70
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• 2020

This paper describes hierarchically stratifying and analyzing haplotrees of haplogroups from haplotypes on the Y and X chromosomes of human cells for genetic and Korean traditional and genealogical trees. The specific region is Chungcheong province, and the Y-DNA of the paternal lines has high frequency of O3a∗ and O2b∗ in the O group, and the mtDNA of the maternal line has a relatively high frequency of D∗ and M∗ in the L3 group. Each combination of these constructs the family tree of the father lines and mother lines. Genetic distances using Nei's standard genetic distance, are very close relatives of less than 0.1 and close relatives of 0.1 to 0.8. Provided, the distance is more than 1.0, it is difficult to estimate relatives. STR has the identified kinship, and SNP has the personal genetic identification. A scientific stratification of the Korean genealogical tree is created by the three factors.

• The Journal of the Convergence on Culture Technology
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• v.8 no.6
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• pp.891-897
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• 2022

In big data analysis, raw text data mostly exists in various unstructured data forms, so it becomes a structured data form that can be analyzed only after undergoing heuristic pre-processing and computer post-processing cleansing. Therefore, in this study, unnecessary elements are purified through pre-processing of the collected raw data in order to apply the wordcloud of R program, which is one of the text data analysis techniques, and stopwords are removed in the post-processing process. Then, a case study of wordcloud analysis was conducted, which calculates the frequency of occurrence of words and expresses words with high frequency as key issues. In this study, to improve the problems of the "nested stopword source code" method, which is the existing stopword processing method, using the word cloud technique of R, we propose the use of "general stopword corpus" and "user-defined stopword corpus" and conduct case analysis. The advantages and disadvantages of the proposed "unstructured data cleansing process model" are comparatively verified and presented, and the practical application of word cloud visualization analysis using the "proposed external corpus cleansing technique" is presented.

• Nuclear Engineering and Technology
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• v.27 no.5
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• pp.701-709
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• 1995

The realistic discharge coefficient for the critical How model of RELAP5/AOD3/KAERI are determined for the subcooled and too-phase critical flow by assessments of nine MARVIKEN Critical flew Test(CFT). The selected test runs include a high initial subcooling and large nozzle aspect rat-io(L/D). The code assessment results show that RELAP5/MOD3/KAERI over-predicts the subcooled critical flow and under-predicts the two-phase critical flow. Using these result, the realistic discharge coefficients of critical flow models are quantified by an iterative method. The realistic discharge coefficients are determined to be 0.89 for the subcooled critical How and 1.07 for the two-phase critical flow, and the associated standard deviations are 0.0349 and 0.1189, respectively. The results obtained from this study can be applied to calculate the realistic system response of Large Break Loss of Coolant Accident and to evaluate the realistic Emergency Core Cooling System performance.

• Composites Research
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• v.19 no.5
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• pp.12-19
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• 2006

In this paper, conceptual structural design of the main wing for a small scale WIG(Wing in Ground Effect) among high speed ship projects, which will be a high speed maritime transportation system for the next generation in Rep. of Korea, was performed. The Carbon/Epoxy material was selected for the major structure, and the skin-spar with a foam sandwich structural type was adopted for improvement of lightness and structural stability. As a design procedure for the present study, firstly the design load was estimated through the critical flight load case study, and then flanges of the front and rear spars from major bending loads and the skin and the spar webs from shear loads were preliminarily sized using the netting rule and the rule of mixture. Stress analysis was performed by a commercial FEA code, NASTRAN. From the stress analysis results for the first designed wing structure, it was confirmed that the upper skin between the front spar and the rear spar was unstable fer the buckling. Therefore in order to solve this problem, a middle spar and the foam sandwich type structure at the skin and the web were added. After design modification, the structural safety and stability for the final design feature was confirmed. In addition to this, the insert bolt type structure with eight high strength bolts to fix the wing structure to the fuselage was adopted for easy assembly and removal as well as in consideration of more than 20 years fatigue life.