• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.3
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• pp.141-150
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• 2013

Simulation is an important technique to test and verify routing protocol correctness. However, simulation does not guarantee that the protocol works expectedly on a real world environment because it needs to rely on assumptions and simplified properties such as radio characteristics and effects of geographical constraints that may not reflect the real world networking environments. Therefore, a real world experiments are necessary to gain a practical insight into the actual performance of ad hoc networks. In this paper, we build a test-bed to evaluate multi-hop ad hoc networks for high speed video streaming inside a building using AODV-UU routing protocol. Our observation indicates that the considered ad hoc network can provide a sufficient performance for a low rate streaming data in terms of throughput, PDR (Packet delivery ratio) and the average delay.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.4950-4955
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• 2012

A bolt manufacturing process is completed with continuous forging. Technical and economical success of each process will depend on the appropriate process design and metal mold design for each procedure. This study aims to analyze the moldings of first and second steps among the multi-step molding processes of SCM435 bolt by use of the finite element method in order to achieve the reasonable process. Since the processes of first and second steps analyzed by use of the finite element method consist of axial symmetry, the transformed configuration of material satisfy the dimensions expected in process. In addition, the uniflow line formed in material becomes smooth and consistent over the entire process. Therefore neither molding of material nor inherent defect is expected.

• Spatial Information Research
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• v.23 no.6
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• pp.31-41
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• 2015

This research is primarily intended to explore a novel way to monitor desiccation of inland wetland by combining MNDWI (Modified Normalized Difference Water Index) and NDVI (Normalized Difference Vegetation Index). The changes for vegetation and water condition on Upo Wetland located at southeastern Korea were investigated by MNDWI and NDVI derived from 2002, 2010 and 2015 Landsat data. The integrated use of MNDWI and NDVI made it possible to identify area-wide vegetation cover changes and to assess water storage changes on multi-annual time scales simultaneously. Comparing MNDWI with NDVI reveals the quantitative evidences for anthropogenic and environmental influences (such as road, building, water) causing an accelerated wetland desiccation. In fact, our monitoring approach raises critical issues regarding the hydrological cycle and its inter-annual changes for inland wetland under threat of drying up and highlights the important role of MNDWI and NDVI integration for any urgent or long-term treatment plan. This research presents scientific and objective evidences to support integrated approach of NDVI and MNDWI in exploring drying up trends of wetlands.

• Earthquakes and Structures
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• v.14 no.1
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• pp.1-10
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• 2018

Seismic retrofitting of existing buildings and design of earth-quake resistant buildings are important issues associated with earthquake-prone zones. Use of metallic-yielding dampers as an energy dissipation system is an acceptable method for controlling damages in structures and improving their seismic performance. In this study, the optimal distribution of dampers for reducing the seismic response of steel frames with multi-degrees freedom is presented utilizing the uniform distribution of deformations. This has been done in a way that, the final configuration of dampers in the frames lead to minimum weight while satisfying the performance criteria. It is shown that such a structure has an optimum seismic performance, in which the maximum structure capacity is used. Then the genetic algorithm which is an evolutionary optimization method is used for optimal arrangement of the steel dampers in the structure. In continuation for specifying the optimal accurate response, the local search algorithm based on the gradient concept has been selected. In this research the introduced optimization methods are used for optimal retrofitting in the moment-resisting frame with inelastic behavior and initial weakness in design. Ultimately the optimal configuration of dampers over the height of building specified and by comparing the results of the uniform deformation method with those of the genetic algorithm, the validity of the uniform deformation method in terms of accuracy, Time Speed Optimization and the simplicity of the theory have been proven.

• Journal of Korea Water Resources Association
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• v.48 no.7
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• pp.535-543
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• 2015

Measurements of multiphase flows containing bubbles have been limited because most existing methods target one phase flows. Especially, multiphase flows with a high void ratio have been rarely successful in measurements due to the sudden change of density and thick interfaces between air and water. This study introduces two methods that are capable of measuring flow fields regardless of bubble void ratio, named bubble image velocimetry and bundle fiber optic flow meter. The calculation of the depth of field is suggested to reduce and estimate errors by perspective image velocimetry. The bundle fiber optic flow meter is designed to increase a measurement rate using many optical fibers with a thin diameter. The two methods measured bubble plumes to test reliability and the velocity measurements show good agreement. In addition a hydraulic jump, one of the multiple flows in rivers was measured to test applicability of the methods.

• Journal of Digital Convergence
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• v.13 no.10
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• pp.225-234
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• 2015

This study focused on building the convergence framework of decision-making for camping site selection attributes. The first stage of study is to identify the camping motivations. The camping motivations are composed of 5 factors. The second stage is to identify the camping site selection attributes. They are composed of 4 factors. The relationships between camping site selection attributes and camping motivations are examined through the multi-regression analysis. The camping site selection attributes were significantly influenced by thr type of camping motivation. Lastly, the relationship between camping site selection attributes and camper's satisfaction and behavioral intention are testified. The implications are that camping site operators and developers need to understand the segmented camping motivations and site selection attributes. They could be the guideline of implementing the developing planning strategies of camping site.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.744-749
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• 2016

This paper presents the design of a computer-generated hologram for beam control of an LCOS-based wavelength selective switch, which is the core technology for next-generation ROADM. By introducing a computer-generated hologram instead of general grating patterns to control the LCOS device, we contribute to building a more efficient wavelength selective switch. With the use of phase modulation properties of LCOS devices, we designed the hologram for five-port output and a 40-channel wavelength selective switch. We applied a multi-level phase modulation technique with the Gerchberg-Saxton algorithm to produce the hologram, which is easily scalable to any different type of wavelength selective switch. With an experimental setup, we verified the usability of the hologram designed for five-port output. We also suggest a hologram design technique for beam control of a 40-channel wavelength selective switch.

• Korean Journal of Health Education and Promotion
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• v.23 no.2
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• pp.121-140
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• 2006

Objectives: Safety is a primary health promotion issue in worksite because injury induces multi-fold loss of the human and economic resources to profit organization. The purposes of this study were to describe worksite health and safety education and management status in Korean manufacturing companies. Methods: The original population size of Korean manufacturing industry in 2004 was 74,398 and 2,960 factories were selected by the multiple stratified sampling method for this study. The health and safety manager or representatives of the selected 2,960 companies successfully finished in the face-to-face interview survey about company's general characteristics, health and safety management style, health and safety education hours conducted by the Korean Occupational Safety and Health Agency. Results: The manufacturing companies in Seoul and Kyunggi areas, small size, and clothes and press industries were related to low health and safety management and education status. The companies which assigned at least one safety manager were 70.5% and which had a health and safety room within the company were only 9.3%. The companies which took the health and safety education for their regular blue-collar employees more than the legal education hours were under 56.1% and the percentage of the companies which took their health and safety education for newcomers less than the legal limits was lower than any other types of health and safety education in workplace. The significant strong workplace health and safety management variables in predicting employee health and safety education were psycho-social variables such as the company own health and safety regulation and the workplace health and safety management committee organization. rather than physical variables such as health manager employment, safety manager employment. Conclusions: Systematic and legal approaches are effective to encourage workplace health and safety education, specifically, through sustaining health and safety managers and building the company-wide health and safety management system. Furthermore, theses approaches should primarily focus on the small companies of which sizes were under 50.

• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.9_10 s.157
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• pp.1400-1412
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• 2006

As PB market segments into premium market, PBs were drawing attentions in terms of creating profits as well as a means to differentiate building up store identity. The purpose of this study makes a comparative study on the difference of consumer attitude formation process in discount store and home-shopping distribution channel which are recently on the upswing. This paper investigated the consumer's attitude formation on the private apparel brand. Subjects of this study were consumers in their $20s{\sim}40s$ who are main customer groups of PBs. The data were analyzed by Structural Equation Modeling and Multi-Group Analysis of Amos 5.0 to verify the difference of the path between store PB and premium PB. Following are the results of the study. Consumer attitude formation path on PB grades showed statistically noticeable difference. In discount store PB, store evaluation didn't directly influence on consumer attitude formation but showed indirect effect. On the other hand, in home shopping premium PB case, product evaluation directly influenced on consumer attitudes with store evaluation. Hedonic attitude dimension connected with behavioral attitude(purchase intention) revealed difference in path. Also consumer's evaluation on variables in model turned out to be different according to brand grade.

• Journal of the Society of Disaster Information
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• v.12 no.1
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• pp.47-53
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• 2016

Techniques to be developed in this study is intended to apply to an existing integrated control system to "A Study on the multiple Texture Rendering system for three-dimensional Image Signal Recognition" technology or become a center of the building control system in real time video. so, If the study plan multi-image mapping system developed, CCTV camera technology and network technology alone that is, will be a number of security do not have to build a linked system personnel provide services that control while the actual patrol, the other if necessary systems and linked to will develop a system that can reflect the intention Ranger.