• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.602-606
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• 2008

LCD is supplied light by BLU(Back Light Unit) and the light represents color by each color filter. Also LCD adjusts the amount of light by controlling liquid crystal between the glass of upper plate and one of lower. However, it is impossible to completely exclude light due to the structural and physical characteristic of liquid crystal. Therefore, on transfering light through optical sheet and liquid crystal, many problems are generated. They are related with energy efficiency and get effective for the contrast of LCD to have lower contrast ratio than other display devices. To solve the problems, many techniques have been studied and developed but don't exist keys to solution for them. Among methods, local dimming is one example to be applied to LCD. In this paper we propose image processing algorithm for local dimming of BLU of LED used as light source. The proposed algorithm extracts maximum luminance signal and lights using each extracted signal on segmented region of BLU. Also the proposed algorithm generates image signal in corresponding to luminance of the segmented region and supplies them with LCD panel to represent image with improving luminance ratio.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.6
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• pp.21-28
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• 2016

This paper presents a cooperative transmission scheme for underwater acoustic sensor networks to improve packet transmission rate and reduce energy consumption. Source node transmits duplicated information relayed by distributed antennas called a virtual antenna array. Destination node combines that information to reduce packet error rate. The suggested cooperative scheme enhances the reliability by providing high diversity gains through intermediate relay nodes to overcome the distinct characteristics of the underwater channel, such as high transmission loss, propagation delay, and ambient noises. It is suggested that the algorithm select destinations and potential relays from a set of neighboring nodes that utilize distance cost, the residual energy of each node and local measurement of the channel conditions into calculation. Simulation results show that the proposed scheme reduces average energy consumption, response time, and increases packet delivery ratio compared with the SPF(Shortest Path First) and non-cooperative scheme using OPNET Moduler.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.2
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• pp.225-237
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• 2011

For each local town (6 cities and 8 counties) affiliated with Jeonbuk provincial government, characteristics of greenhouse gas (GHG) emissions were analyzed and key emission areas were drawn to establish mitigation policies of the regional greenhouse gases. National Institute of Environmental Research (NIER) reported that the total greenhouse gas emission of Jeonbuk was 20.93 million $tCO_2e$ in 2006. The inland area of 5 cities and 1 county (Jeonju, Gunsan, Iksan, Jungeup, Kimje, Wanju) covered 82% of total greenhouse gas emission in Jeonbuk, while the rest local towns of the province, mostly from mountainous areas were responsible for the rest of the total GHG emission. The cities and counties having relatively higher emission in Jeonbuk province were influenced dominantly by the emission from energy and waste sections. Also, agricultural section showed similar tendency except industrial cities such as Gunsan and Jeonju. In the internal portion of city and county, energy section showed the highest portion at the range of 72.1 (Sunchang)~97.0% (Jeonju) and agricultural section was at the range of 1.2% (Jeonju)~26.6 (Sunchang). When the portion of energy section was higher, the lower agricultural section. The emission index was applied to decide the key city and county and the potential city and county with two methodologies in this study. It was required that the key emission areas were drawn to establish regional greenhouse gases mitigation policies.

• Structural Engineering and Mechanics
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• v.13 no.4
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• pp.369-385
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• 2002

Ductility capacity is comprehensively studied for steel moment-resisting frames. Local, story and global ductility are being considered. An appropriate measure of global ductility is suggested. A time domain nonlinear seismic response algorithm is used to evaluate several definitions of ductility. It is observed that for one-story structures, resembling a single degree of freedom (SDOF) system, all definitions of global ductility seem to give reasonable values. However, for complex structures it may give unreasonable values. It indicates that using SDOF systems to estimate the ductility capacity may be a very crude approximation. For multi degree of freedom (MDOF) systems some definitions may not be appropriate, even though they are used in the profession. Results also indicate that the structural global ductility of 4, commonly used for moment-resisting steel frames, cannot be justified based on this study. The ductility of MDOF structural systems and the corresponding equivalent SDOF systems is studied. The global ductility values are very different for the two representations. The ductility reduction factor $F_{\mu}$ is also estimated. For a given frame, the values of the $F_{\mu}$ parameter significantly vary from one earthquake to another, even though the maximum deformation in terms of the interstory displacement is roughly the same for all earthquakes. This is because the $F_{\mu}$ values depend on the amount of dissipated energy, which in turn depends on the plastic mechanism, formed in the frames as well as on the loading, unloading and reloading process at plastic hinges. Based on the results of this study, the Newmark and Hall procedure to relate the ductility reduction factor and the ductility parameter cannot be justified. The reason for this is that SDOF systems were used to model real frames in these studies. Higher mode effects were neglected and energy dissipation was not explicitly considered. In addition, it is not possible to observe the formation of a collapse mechanism in the equivalent SDOF systems. Therefore, the ductility parameter and the force reduction factor should be estimated by using the MDOF representation.

• Tunnel and Underground Space
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• v.27 no.1
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• pp.1-11
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• 2017

Most of the local limestone mines are developed as large-opening underground mines, while mine ventilation is heavily dependent on the natural ventilation and auxiliary systems, rather than the mechanical ventilation system using main fans. The current auxiliary ventilation system with fan and ducting requires optimization since enhanced deployment of diesel equipment demands higher airflow rate and the associated cost is expected to be too excessive for the local mine operators. This paper aims at optimizing the fan capacity for the working site ventilation through comparing the fan pressure in the mine airway and the ventilation efficiency of an axial-flow fan and a propeller fan developed in this study.

• The Journal of Korean Physical Therapy
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• v.24 no.3
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• pp.202-207
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• 2012

Purpose: The purpose of this study was to determine the effect of monochromatic infrared energy (MIRE) on the blood flow of the superficial radial artery and local skin temperature in healthy subjects. Methods: Forty healthy volunteers were recruited and randomly assigned to MIRE group (n=20) and placebo group (n=20). The MIRE group received a 890 nm MIRE irradiation on the forearm using two therapy pads for 30 minutes. The therapy pad was composed of an array of 60 diodes. MIRE unit was set at bar 8, that corresponds to a diode power of 10 mW and a power density of $63mW/cm^2$. The placebo group received sham MIRE. Peak blood flow velocity (PBFV), mean blood flow velocity (MBFV), and skin temperature (ST) were measured pre- and post-MIRE irradiation. Results: There was a significant difference in PBFV (p<0.001), MBFV (p<0.001), and ST (p<0.001) between the pre- and post-treated values in the MIRE group. In contrast, no significant difference was found between the pre- and post-treated values in the placebo group. There was significant difference in mean change values from baseline of PBFV (p<0.001), MBFV (p<0.001), and ST (p<0.001) between the MIRE group and the placebo group. There was a significant increase in PBFV (p<0.001), MBFV (p<0.001), and ST (p<0.001) following MIRE irradiation. Conclusion: The arterial blood flow and local skin temperature of the forearm in the healthy subjects were significantly increased following MIRE irradiation.

• Tunnel and Underground Space
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• v.25 no.6
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• pp.543-555
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• 2015

At present, local limestone mines with large opening employ auxiliary fans for workplace ventilation which have been used in coal mines with much smaller airways. Considering the low static pressure loss in the large-opening mines, high pressure auxiliary fans face serious economical limitations mainly due to their excessive capacity. The optimal fan selected for the ventilation in large-opening working places should supply air quantity enough for maintaining safe environment and keep its operating cost as low as possible. This study focuses on the development of a low pressure auxiliary fan designed to have smaller range of the static head but to have more potential for higher ventilation and energy efficiency. The flow characteristics of high and low pressure auxiliary fans were theoretical as well as experimentally investigated to assess the ventilation efficiency in term of environmental and economical aspects. Moreover, the low pressure fan was tested in two limestone mine sites with small and large cross-sectional areas for evaluating its ventilation efficiency. Results from this study can be applied to improve the economy and efficiency of auxiliary fan for ensuring better air quality and work environment management.

• The Korean Journal of Food And Nutrition
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• v.14 no.2
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• pp.106-112
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• 2001

The purpose of this study was to investigate to the effect of regular exercise on nutrients intakes and energy balance related to food habit and nutrient knowledge of college women. This study was conducted from May to June in 2000. One hundred and forty female students made their three day dietary records by 24-hr recall method and one day activity record. The questionaires were designed to fine out food habit and nutrition knowledge status. The height. weight and blood pressure were measured and also body fat mass and lean body mass measurements were performed. The results obtained are summerized as follows. Average height and weight of E(exercise) group were found to be increased than those of NE(non-exercise) group. The percent of body fat and body fat mass(kg) in E group were slightly lower than those of NE group. Calorie intake of NE group was 1,664kca1 per day. This was composed of carbohydrate 60%kcal. protein 14%local and fat 24%local. Calorie, calcium, iron, vitamin A, vitamin B$_2$ and niacin intakes of NE group were lower than those of RDA and calorie intake of E group was 2.313kca1 per day. This was composed of carbohydrate 54%, protein 13% and fat 31%. Other nutrients such as iron, vitamin A, niacin and vitamin C were lower than those of RDA. Daily energy expenditure and physical activity of E group were 2,397.6$\pm$49.2kca1; 1,035.7 $\pm$36.5kcal, respectively and it was higher than those of NE group.

• Journal of the Korean Society for Railway
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• v.12 no.4
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• pp.590-596
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• 2009

In this study, the failure modes and energy absorption characteristics of four different kinds of circular tubes made of carbon, glass, Kevlar and carbon-Kevlar hybrid fibres composites with epoxy resin have been evaluated. To achieve these goals, compressive tests were conducted for the tubes under 10mm/min loading speed. Based on the test results, the carbon/epoxy tube showed the best energy absorption capability, while carbon-Kevlar/epoxy tubes were worst. In the failure mode during crushing, both of the carbon/epoxy tubes and the glass/epoxy tubes were crushed by brittle fracturing mode. The Kevlar/epoxy tubes were collapsed by local buckling mode like steel, while the carbon-Kevlar hybrid tubes were collapsed by mixed mode of local buckling and lamina bending.

• Journal of Energy Engineering
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• v.24 no.1
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• pp.10-16
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• 2015

Recently, RCM(reliability centered maintenance) process is introduced and applied for the planning and implementing efficient and effective maintenance system in terms of optimal rolling stock maintenance. Particularly, cost-time benefits analysis associated with the implementation of RCM for rolling stock maintenance is necessary and required for railway operator in advance. The RCM process was primarily starting from military, airplane and nuclear industries and is now adapted in railway industry for local railway operators. This paper focuses on suggesting the way of connecting the RCM process with railway maintenance activities in the railway operation field. Thus, in order to introduce and establish reliability activities, it needs to review and evaluate the maintenance environment in the organizational point of view. Based on these reviews and evaluations, various maintenance methodologies are reviewed for customizing local railway field situations and establish specific process in the application of major systems on the reliability technology. In this paper, the railway RCM process is proposed for the establishment and construction of the systematic and optimal maintenance system.