• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1042-1049
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• 2007

Recently, a theoretically-sound design approach, using an elastic multilayer model, is attempted in trackbed designs for the construction of high speed railways and new lines of conventional railways. In the elastic multilayer model, the stress-dependent resilient modulus($E_R$) is an important input parameter, that is, reflects substructure performance under repeated traffic loading. However, the evaluation method for resilient modulus using repeated loading triaxial test is not fully developed for practical purpose, because of costly equipment and the significantly fluctuated values depending on the testing equipment and laboratory personnel. In this study, the paper will present an indirect method to estimate the resilient modulus using dynamic properties. The resilient modulus of crushed stone, which is the typical material of sub-ballast, was calculated with the measured dynamic properties and the range of stress level of the sub-ballast, and approximated with the power model combined with bulk and deviatoric stresses. The resilient modulus of coarse grained material decreases with increasing deviatoric stress at a confining pressure, and increases with increasing bulk stress. Sandy soil(SM classified from Unified Soil Classification System) of subgrade was also evaluated and best fitted with the power model of deviatoric stress only.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2005.09a
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• pp.263-266
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• 2005

We made a stepping stone for asthma study by analyzing an asthma-specific protein-protein interaction network. It follows the power-law degree distribution and its hub nodes and skeleton frame of the network agreed with the prior knowledge about asthma pathway. This study is providing a systematic approach to analyze the complex effect of genes or to represent the frame of their relations associated with specific disease.

• Proceedings of the KSR Conference
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• 2003.10b
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• pp.176-181
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• 2003

Damages by vibration and noise due to the construction performance are increasing. The rise of construction demand and enlargement of equipments are major reasons of this damage. As a result, the enmity of the people is provoked and this appears to be an obstacle of construction work. Especially, in case of ground improvement construction. Casing pipe is inserted into the Sand Drain, Sand Compaction Pile and Vibrated Crushed-stone Pile by vibration power when carrying out. Hence, a pillar is formed and it creates vibration and noise. This causes a lot of restrictions to construction condition. The low Vibration and low noise construction equipments uses earth auger and hydrulic cylinder for insertion and chopping operation instead of vibro hammer, which is the source of vibration and noise. This minimize ground disturbanceand decrease vibration and noise successfully, but increase chopping effect greatly. Thus, this new equipment is not only suitable for environment but also excellent engineering method of construction.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.101-106
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• 2001

In order to establish the optimum process parameters and diamond saw blade composition for machining natural stone, the chip formation process and the wear process must be understood. Diamond saw blade is one of the most effective, versatile, and extensively used methods of processing rock and other hard materials, such as granite, marble, concrete and asphalt. For many years, it has been known that chip thickness is one of the most significant in the understanding of the sawing process, and other variables such as force and power have been correlated with it. In this study, mathematical relations of a material chipped by a single grit of the saw blade will be undertaken. The material chipping geometries have been mathematically defined and derived as maximum chip thickness.

• Journal of Korea Society of Digital Industry and Information Management
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• v.12 no.1
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• pp.13-26
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• 2016

Service and technology for the future hyper-connected society, which is every information receive through the mobile internet, will be an Internet of Things. Thus, it is mandatory to derive key standardization work item and establish strategy for the global business with the standardization of device and service platform by the application service. In this study, by analyzing the domestic and international market trends, state of technical development, and standardization of technology, we identified the open platform is the stepping stone for achieving the goal which is establishing the virtuous circulation of IoT ecosystem. Also, we defined emphasized key standardization work item for achieving the open platform are network, server, access authentication, billing system, and software platform. After that, we proposed future strategy direction of standardization. This research could be contribute to the IoT service diffusion by realizing IP communication among low power wireless terminals and implementing light-weight standard internet protocol.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.166-167
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• 2013

Bottom ash, which is discharged through a wet process in a thermal power plant, contains much unburned coal due to quenching and much salt due to seawater. However, dry bottom ash discharged through a dry process contains low unburned coal and salt, and has light -weight due to many pores. Therefore, it is expected that it can be used as lightweight aggregate. This study deals with the basic properties of concrete used dry bottom ash as coarse aggregate. As a results, the concrete having high content of dry bottom ash aggregate showed high slump by using water reducing agent and its air content was within 5±1.5% as designed value, similarly to normal weight concrete. It also showed a lower compressive strength than 100% of crushed stone.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.1
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• pp.83-92
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• 2022

Religions and beliefs can affect the shopping behaviors of its followers and practitioners. However, the knowledge about the factors that motivate, facilitate and even constrain customers' purchase of spiritual goods, such as feng shui items, is limited. Therefore, in this study, I examined the reasons, facilitators, and constraints of purchasing spiritual goods from the buyers' perspective. Two research questions directed the examination process, including (1) why users buy spiritual goods? And (2) what factors may facilitate or constrain the purchase and use of spiritual goods? Using Vietnam's feng shui market as the context, I applied the autoethnographic and ethnographic methods to collect and analyze the data. I found that the two main reasons to purchase the feng shui items were the products' meaning and beauty. In addition, I observed three groups of factors that could facilitate or constrain the purchase and use of feng shui items, including information about the products and their sellers, disposable income and life stage of the buyers, and price and authenticity of the products. Finally, based on these findings, I discussed the practical implications for managing the spiritual goods market in Vietnam.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.904-908
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• 2008

As the various industrial production machinery has come into being by development of industrial technology, the productivity of the basic industrial production machinery has improved and the international competitiveness of the one of Korea has strengthened. However, at the same time, noise from various industrial production machinery disturbs the quiet environment. There are 35 kinds of the noise emission machinery defined in the noise and vibration control act according to the horse power and the number of machinery. These were classified in 1992 through investigation from 1990 to 1991, and the characteristic of the noise emission machinery may be different from the past one. So we need to investigate the characteristics of the noise emitted by machinery to control it rightly. Also we need to investigate the new noise emission machinery which has come into being recently. In this survey, we measured sound intensity of 32 noise emission machinery to calculate the sound power levels of those and investigated the characteristic of the sound power level of those according to the frequency. From the survey, we found that the forging machine, concrete pipe and pile making machine, sawing machine, etc. are the noisy machinery. And the automatic packing machine, sewing machine, centrifuge, etc. are the silent machinery. Also the generator, the concrete pipe and pile making machine, the printing machine, etc. emit the low frequency noise, and the molding machine, the stone cutter, the metal cutter, etc. emit the high frequency noise. Lastly, we intented to propose the proper guide line of classifying noise emission machinery.

• Current Photovoltaic Research
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• v.4 no.4
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• pp.159-163
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• 2016

Piled snow upon PV module interferes with Photoelectric Effect process through photovoltaic directly. As a result of this phenomenon, its generation efficiencies keep decreasing or are stuck at zero power generating status. In addition, PV facilities have been installed on those places such as water surface, roof-top, and other isolated places, dealing with conditions of "Securing high REC weighted value", "Difficulty of securing land" and so forth. Through this study, we are able to actualize the function of heating over PV modules when it snows. We adopted laminating method through heating film and modules, guaranteeing warranty more than for 25 years. Also we are trying remote control systemically, not by hardware control, to run parallel with automatic driving and monitoring system which enable to control operation time, insolation, amount of snowfall automatically. We applied analysis of actual proof to both snow removal PV system and general PV power system, and these led to bear power consumption analysis while snow-removing, and its comparison after finishing the task as "One stone, two birds." In the long run, we could carry out economic analysis against snow removal system, and this helps to verify the most maximized control method for snow removal conditons on a basis of weather information. this study shall let prevent people from negligent accidents, and improve power generation problems as mentioned from the top. Ultimately, we expect to apply this system to heavy snowfall regions in winter season in spite of its limited system installaion in Korean territory, initially.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.5
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• pp.95-108
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• 2011

Smart Grids are intelligent next generating Electric Power System (EPS) that provide environment-friendliness, high-efficiency, and high-trustworthiness by integrating information and communication technology with electric power technology. Smart grids help to supply power more efficiently and safely than past systems by bilaterally exchanging information between the user and power producer. In addition, it alleviates environmental problems by using renewable energy resources. However, smart grids have many cyber security risks because of the bilateral service, the increase of small and medium-sized energy resources, and the installation of multi-sensors or control devices. These cyber risks can cause critical problems within a national grid through even small errors. Therefore, in order to reduce these risks, it is necessary to establish a cyber security strategy and apply it from the developmental stage to the implementation stage. This thesis analyzes and recommends security strategy in order to resolve the security risks. By applying cyber security strategy to a smart grid, it will provide a stepping-stone to creating a safe and dependable smart grid.