• The Transactions of the Korea Information Processing Society
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• v.2 no.1
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• pp.95-105
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• 1995

An appendix to the MAP 3.0 specification notes that there are primary advantages to use of fiber optics : noise immunity, ability to run in difficult electrical environments, safety and high data rates. All of these may be quite useful in various manufacturing environments. In this paper, we study on construction schmes for a fiber-based 802.4 MAP system including the use of both bus and star topologies. We suggest passive star network and FDDI network for manufacturing environment. And then, we propose the FDDI protocol including the use a dual ring topology running at 100 Mbps to physical and datalink layer of MAT specification and analysis it's protocol and topology for abilities in manufacturing environments, We evaluate about applications service, time-critical processing and topology of two models in manufacturing environment.

• The KIPS Transactions:PartC
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• v.17C no.6
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• pp.491-498
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• 2010

Wi-Fi based vehicle-to-infrastructure (V2I) communication is an emerging solution to improve the safety, traffic efficiency, and comfort of passengers. However, due to the high mobility of vehicles and the limited coverage of Wi-Fi APs, the V2I system may suffer from frequent handoffs although roadside APs can support cost effective Internet connectivity. Such problem of V2I systems can be overcome with Mobile AP (MAP) platform. The MAPs yield longer service duration by moving along with vehicles, yet they provide a lower link capacities than the roadside APs. In this paper, we propose a new association control mechanism that effectively determines whether the vehicle will select a fixed roadside-AP or a nearby MAP in mobile vehicular network environments. We consider both the achievable link bandwidth and available connection duration as a selection criterion and provide their run-time estimation method. Extensive simulation using real traces show significant performance improvements.

• Journal of the Korean Home Economics Association
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• v.18 no.4
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• pp.65-73
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• 1980

The purpose of this study is ti find out a desirable way to stability and improvement of household economy by studying the changes of consumption level and consumption pattern of urban salary and wage earners' households during the years from 1970 to 1978. For this study, "Annual Report on the Family Income and Expenditure survey" (Published by the Bureau of Statistics, Economics Planning Board) has been used as basic material, and the methods of analysis used here are the time series analysis. We have gained the results as follows: 1) From 1970 to 198, the total income level increased at the rate of 416.2% in nominal price, but only 74.4% in reql price, while the total expenditure level showed 338.5% increase in nominal price, but its real increased proved only 418.2% in consideration of inflation. APC decreased from 95.1%(in 1970) to 80.7%(in 1978). 2) As for the expenditure pattern for the above mentioned nine years, the rate of food expenditure increased until 1975 under the price influence, but it trended to decease there after on . The rate of housing expenditure showed a gradual increase while that of fuel and light expenditure was on the decrease. The rate of clothing expenditure had been on the decease until 1974 but it began to increase gradually thereafter on. The trend of miscellaneous expenditures was irregularly up and down, educational expences being the first rank among them, Non-living expenditure had been constant until 1974 but it decreased a little after that. From the results it was found that the consumption level of the salary and wage earners' household in all cities from 1970 to 1978 was not practically improved because of rise in prices, nor was the Engel's coefficient and the rate of miscellaneous expenditure changed distinctively. However, as the successive decrease of APC suggests the possibility of economic development, we must try to put stress on economy in consumption and on encouraging. This will help run our household economy in safety and stability.

• Journal of Fashion Business
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• v.4 no.4
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• pp.107-121
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• 2000

The purpose of this study is to offer basic data to adolescents' cosmetic culture by investigating and analysing the choices made by female students who have been becoming principle consumers of cosmetics these days. Firstly, social and cultural backgrounds and concepts of N generation, and then characteristics and influencing powers of female students were reviewed. And this study also included questionnaire surveys of 500 female students in middle and high schools located in Seoul. Data were processed using a SPSS$^+$ program and analyzed by using frequency, percentage and the $X^2$-test. The major findings run as follows: Female students have the effects of spreading their words quickly and abilities of making a decision what to buy. And they accept consuming behaviors itself as a part of cultural lives. Therefore, industries have acknowledged them as new principal consumers with a powerful influence in the market. They also play an important role in active consumer as emotional generation who has distinct personalities and prefer fashion trends, changes and innovations. They show conformities with their peer groups and they also want to identify themselves with characters or stars. The cosmetic behaviors of female students relating to demographic characteristics showed a significant relation to grades, majors, school groups and places of residence. Female students have a lot of interest and knowledge about cosmetics. And they use various cosmetic products. This study demonstrated the age for using make-up for the first time has been becoming younger more and more. Recently, female adolescents tend to use face powder, lip gloss, mascara and eye shadow. It is assumed that cosmetic purchases of female students can be considered as an impulsive aspects. However, before purchases, the proportion of students having any particular cosmetic brand in mind previously has been increasing. They take into consideration skin safety, the quality of product and color, when purchasing cosmetic products.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.80-83
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• 2008

As SOC (Social Overhead Capital) has been expanded, the highway road construction has been accelerated and city road system has been more complicated. So, long road tunnels have been increased and traffic flow rate also has been raised. Accordingly, the exhausting gas of vehicle cars seriously deteriorates the tunnel inside air quality and driving view. In order to improve tunnel inside air quality, we may need to introduce a compulsory ventilation system as well as natural ventilation mechanism. The natural ventilation mechanism is enough for short tunnels, meanwhile longer tunnels require a specific compulsory ventilation facility. Many foreign countries already have been devoting on development of effective tunnel ventilation system and especially, some European nations and Japan have already applied their developed tunnel ventilation system for longer road tunnels. More recently, as the quality of life improved, our concerns about safety of driving and better driving environment have been increased. In order to obtain clearer and longer driving view, we are more interested in EP tunnel ventilation system in order to remove floating contaminants and automobile exhaust gas. Evan though it's been a long time since many European countries and Japan applied more economical and environment-friendly tunnel ventilation system with their self-developed Electrostatic Precipitator, we are still dependant on imported system from foreign nations. Therefore, we need to develop our unique technical know-how for optimum design tools through validity investigation and continuous possibility examination, eventually in order to localize the tunnel ventilation system technology. In this project, we will manufacture test-run products to examine the performance of system in order to develop main parts of tunnel ventilation system such as electrostatic precipitator, high voltage power generator, water treatment system, etc.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.260-260
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• 2017

This study aims to compare the performance of TRIGRS (Transient Rainfall Infiltration and Grid-based Regional Slope-stability model) and TiVaSS (Time-variant Slope Stability model) in the prediction of rainfall-induced shallow landslides. TRIGRS employs one-dimensional (1-D) subsurface flow to simulate the infiltration rate, whereas a three-dimensional (3-D) model is utilized in TiVaSS. The former has been widely used in landslide modeling, while the latter was developed only recently. Both programs are used for the spatiotemporal prediction of shallow landslides caused by rainfall. The present study uses the July 2011 landslide event that occurred in Mt. Umyeon, Seoul, Korea, for validation. The performance of the two programs is evaluated by comparison with data of the actual landslides in both location and timing by using a landslide ratio for each factor of safety class ( index), which was developed for addressing point-like landslide locations. In addition, the influence of surface flow on landslide initiation is assessed. The results show that the shallow landslides predicted by the two models have characteristics that are highly consistent with those of the observed sliding sites, although the performance of TiVaSS is slightly better. Overland flow affects the buildup of the pressure head and reduces the slope stability, although this influence was not significant in this case. A slight increase in the predicted unstable area from 19.30% to 19.93% was recorded when the overland flow was considered. It is concluded that both models are suitable for application in the study area. However, although it is a well-established model requiring less input data and shorter run times, TRIGRS produces less accurate results.

• The Korean Journal of Archival Studies
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• no.74
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• pp.155-186
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• 2022

As of 2022, the number of Internet sites for public institutions registered on the 'Government 24' website (www.gov.kr) of the Ministry of the Interior and Safety is 17,000. The direct transfer takes a lot of human and material resources and time between the records-producing institution and the records-management institution that manages websites as records. In addition, it is practically difficult for records management institutions to migrate and operate various software and application technologies required to run each website. A method of automatically collecting websites from a remote location using web crawler software is used domestically and abroad to overcome these practical limitations. This study compared the performance of the web crawler required to collect and manage public Internet websites as records remotely. The most suitable web crawler was selected through a step-by-step review of several web crawlers from previous studies and other literature. Several public agency websites were applied to compare the actual performance of the crawlers in the evaluation process. The study provides empirical and specific performance comparison information for organizations that need to choose a web crawler.

• Journal of the Korea Institute of Military Science and Technology
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• v.26 no.1
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• pp.91-101
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• 2023

Modeling and Simulation(M&S) technology has been widely used to solve constraints such as time, space, safety, and cost when we implement the same development and test environments as real warfare environments to develop, test, and evaluate weapon systems for the last several decades. The integration and test environments employed for development and test & evaluation are required to provide Live Virtual Construction(LVC) simulation environments for carrying out requirement analysis, design, integration, test and verification. Additionally, they are needed to provide computing environments which are possible to reconfigure computing resources and software components easily according to test configuration changes, and to run legacy software components independently on specific hardware and software environments. In this paper, an Integration Test and Simulation for Engagement Control(ITSEC) bed using a bare-metal virtualization mechanism is proposed to meet the above test and simulation requirements, and it is applied and implemented for an air missile defense system. The engagement simulation experiment results conducted on air and missile defense environments demonstrate that the proposed bed is a sufficiently cost-effective and feasible solution to reconfigure and expand application software and computing resources in accordance with various integration and test environments.

• Smart Structures and Systems
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• v.29 no.5
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• pp.653-660
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• 2022

Gravel scattering that is generated during operation of high-speed railway vehicle is cause to damage of vehicle such as windows, axle protector and so on. Especially, those are frequently occurred in winter season when snow ice is generated easily. Above all, damage of vehicle windows has not only caused maintenance cost but also increased psychological anxiety of passengers. Various methods such as heating system using copper wire, heating jacket and heating air are applied to remove snow ice generated on the under-body of vehicle. However, the methods require much run-time and man power which can be low effectiveness of work. Therefore, this paper shows that large-area heating system was developed based on heating coat in order to fundamentally prevent snow ice damage on high-speed railway vehicle in the winter season. This system gives users high convenience because that can remotely control the heating system using IoT-based wireless communication. For evaluating the applicability to railroad sites, a field test on an actual high-speed railroad operation was conducted by applying these techniques to the brake cylinder of a high-speed railroad vehicle. From the results, it evaluated how input voltage and electric power per unit area of the heating specimen influences exothermic performance to draw the permit power condition for icing. In the future, if the system developed in the study is applied at the railroad site, it may be used as a technique for preventing all types of damages occurring due to snow ice in winter.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.4
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• pp.1178-1185
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• 2010

Recently, high speed of container freight cars is causing fatigue damage of wheel. Sudden failure accidents cause a lot of physical and human damages. Therefore, damage analysis for wheel prevents failure accident of container freight car. Wheel receives mechanical and thermal loads at the same time while rolling stocks are run. The mechanical loads applied to wheel are classified by the horizontal load from contact of wheel and rail in curve line section and by the vertical force from rolling stocks weight. Also, braking and deceleration of rolling stocks cause repeated thermal load by wheel tread braking. Specially, braking of rolling stocks is frictional braking method that brake shoe is contacted in wheel tread by high breaking pressure. Frictional heat energy occurs on the contact surface between wheel tread and brake shoe. This braking converts kinetic energy of rolling stocks into heat energy by friction. This raises temperature rapidly and generates thermal loads in wheel and brake shoe. There mechanical and thermal loads generate crack and residual stress in wheel. Wetenkamp estimated temperature distribution of brake shoe experimentally. Donzella proposed fatigue life using thermal stress and residual stress. However, the load applied to wheel in aforementioned most researches considered thermal load and mechanical vertical load. Exact horizontal load is not considered as the load applied to wheel. Therefore, above-mentioned loading methods could not be applied to estimate actual stress applied to wheel. Therefore, this study proposed safety estimation on wheel of freight car using heat-structural coupled analysis on the basis of loading condition and stress intensity factor.