• 한국산림과학회지
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• 제97권2호
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• pp.156-164
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• 2008

Recognizing the importance of the multi-purpose management of natural deciduous forest, this study was carried out to implement the partial cutting for stand regulation to examine agroforestry practice as well as other concurrent forest resource production, and to investigate the changes in stand characteristics and understory vegetation in a silvopasture practiced natural deciduous stand in the Research Forest of Kangwon National University, Korea. Three different partial cutting intensities (68.1%, 48.6%, and control) were performed in the unmanaged natural deciduous stand in order to improve the growing condition, especially light condition, for introducing some commercial herbaceous plants on the forest floor to establish agroforestry and/or silvopastoral system. Dominated by Quercus varibilis Blume (50.5%) and Quercus dentata Thum. ex Murray (42.6%), eight tree species were composed of the study forest, including poles of Pinus desiflora Siebold & Zucc and sapling of Pinus Koraiensis Siebold & Zucc. The total of 87 (13 tree species, 12 shrub species, 58 herbaceous species, and 4 woody climbers) vascular plant species were observed in study site after partial cutting treatments, while that of before partial cutting was 53 species (14 tree species, 8 shrubs species, 30 herbaceous species, and 1 woody climbers). The proportion of life form spectra in plot B was Mi (28.4%)-Na (23.0%)-Ge (17.5%)-Ch (10.8%)-He (9.5%)-MM (6.7%)-Th (4.1%). No statistically significant differences were observed in changes of life form spectra from before to after partial cutting treatment and among partial cutting gradients in this study. Partial cutting and scratching for forage sowing made plants invade easily on the forest floor, and light partial cutting (LPC) plot (500 stems/ha) had much higher number of undersory species than those of heavy partial cutting (HPC) plot (310 stems/ha) and control plot (1,270 stems/ha).

• KIEAE Journal
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• 제10권4호
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• pp.137-145
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• 2010

Active sunlighting systems have been applied to deliver sunlight into the indoor space where natural light is insufficient, mainly because of the congested high-rise buildings in urban areas. Among various active sunlighting systems, a mirror sunlighting system which is simple structure and economically reasonable has been widely used in different types of spaces such as underground, north facing place and atrium. This study was to evaluate the mirror sunlighting systems, which were consisted of the first mirror of $3.5m{\times}2.5m$, the eight sets of the second mirrors of $1.0m{\times}1.25m$ and a sun tracker. Ten sets of the systems were installed for 40 apartment living rooms, the configuration of $3.5m(W){\times}4.0m(D){\times}2.5m(H)$ where sunlighting were not possible due to high retaining walls located in the front of the living rooms. The 45 HOBO data logger sensors for the indoor illuminance were equipped and 2 Li-cor photometers for outdoor illuminance. Both indoor and outdoor horizontal illuminances were monitored every second from 9am to 3pm on 17 January 2010 under clear sky condition. The results showed that the indoor illuminance of installed mirror sunlighting system was significant relationship with outdoor illuminance and increased the indoor illuminance level by 4.2 times on the whole floor space, by 8 times on the sun patch space of 6m2 and even by 2 times on the no sun patch space. In addition, the luminous conditions of the living room under real sky conditions met the KS recommendation for difficult task (600-1000-1500 lux) such as sewing and reading on whole floor space and sun patch space. It was proved that the benefits of mirror sunlighting systems included an effective technology for penetrating daylight into indoors where sunlighting was not possible and improving occupants' satisfaction and health, and contributing to energy saving in apartments during daytime.

• Safety and Health at Work
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• 제4권2호
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• pp.105-110
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• 2013

Background: To determine the influence of lifting speed and type on peak and cumulative back compressive force (BCF) and shoulder moment (SM) loads during symmetric lifting. Another aim of the study was to compare static and dynamic lifting models. Methods: Ten male participants performed a floor-to-shoulder, floor-to-waist, and waist-to-shoulder lift at three different speeds [slow (0.34 m/s), medium (0.44 m/s), and fast (0.64 m/s)], and with two different loads [light (2.25 kg) and heavy (9 kg)]. Two-dimensional kinematics and kinetics were determined. A three-way repeated measures analysis of variance was used to calculate peak and cumulative loading of BCF and SM for light and heavy loads. Results: Peak BCF was significantly different between slow and fast lifting speeds (p < 0.001), with a mean difference of 20% between fast and slow lifts. The cumulative loading of BCF and SM was significantly different between fast and slow lifting speeds (p < 0.001), with mean differences ${\geq}80%$. Conclusion: Based on peak values, BCF is highest for fast speeds, but the BCF cumulative loading is highest for slow speeds, with the largest difference between fast and slow lifts. This may imply that a slow lifting speed is at least as hazardous as a fast lifting speed. It is important to consider the duration of lift when determining risks for back and shoulder injuries due to lifting and that peak values alone are likely not sufficient.

• 한국안전학회지
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• 제34권1호
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• pp.90-97
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• 2019

This study is aiming to compare stair ascent transportation speed and physical burden of evacuation supporters according to the types of stair ascent transportation for vulnerable people experimentally. In this study, we measured heart rate of the supporters to indicate physical burden during the transportation. The subjects of this experiment were male students, age of 20-26. Experimental conditions were the ways of stair transportation and the weight of vulnerable people. The types of stair transportation were giving a piggyback ride and carrying a wheelchair. Each experimental trial was video-recorded for measurement of ascent speed and observing supporters movement. As a result of the experiment, as for the ascent transportation speed by piggyback ride from the first floor to the fourth floor, the average speed of the light case is 31 seconds and for the heavy case is 43 seconds. When it comes to the average speed of wheelchair transportation's average speed the light case is 1 minute and 11 seconds and the heavy case is 1 minute and 49 seconds. Therefore, it was indicated that when the weight of a vulnerable people is lighter, the transportation speed is faster. The heart rates of evacuation supporters are different depending on transportation methods or individual's condition but as repetitive transportation increases, they tend to reach the maximum heart rates.

• 한국가금학회지
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• 제45권4호
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• pp.245-252
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• 2018

본 연구는 LED 조명의 색(파장)이 평사에서 사육하는 갈색 산란계의 생산성, 계란의 품질, 난황 콜레스테롤, 혈액 및 난관 $17{\beta}$-에스트라디올과 프로게스테론의 농도에 미치는 영향을 알아보기 위하여 수행하였다. 각각 적색, 청색, 녹색, 백색의 LED 조명색으로 총 4처리를 두었고, 47주령 갈색 산란계 144수를 처리당 4반복(칸), 반복당 9수로 배치한 후 6주간 시험을 진행하였다. 파장이 긴 적색 조명 그룹의 산란율이 가장 높았으며, 이 그룹의 혈중 $17{\beta}$-에스트라디올의 분비 농도도 가장 높았다. 반면 파장이 짧은 녹색 조명 그룹의 산란율이 가장 낮았으나, 난중은 가장 무거운 것으로 나타났다. 또한 LED 조명의 색은 난각 색, 난각 강도, 호우 유닛(HU)과 난황 내 콜레스테롤 함량에도 영향을 미치고 있음을 확인할 수 있었다. 따라서 본 연구를 통해 광원으로서 LED 조명의 경우 조명의 색(파장)이 산란 및 번식대사에 비슷하게 작용함을 확인하였다. 또한 이미 충분한 성 성숙이 완료되고, 산란율이 감소하기 시작하는 주령에도 광 자극이 산란 및 번식 대사에 영향을 미치고 있음을 알게 되었다. 본 연구의 결과로 산란성적, 계란 품질, 번식 호르몬 분비를 고려할 때, 평사에서 사육하는 47주령의 갈색 산란계에 적색 LED 조명이 가장 유리하다는 점을 제안할 수 있게 되었다.

• 중소기업융합학회논문지
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• 제6권4호
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• pp.99-106
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• 2016

본 논문에서는 White 색상을 달성하기 위한 R, G, B 혼합비율 Type을 기반으로 상대적으로 열화된 BER성능을 달성하는 파장 대역에 Forward Error Correction (FEC) 기법을 적용하여, 전체 시스템의 BER성능을 향상 시킬 수 있는 가시광 통신 시스템을 제안한다. FEC기법으로 Low Density Parity Check (LDPC) 코드를 적용하였으며, LDPC 부호는 Shannon의 한계치에 가장 근접하는 오류정정 부호로 평가되고 있으며, 오류마루(error floor) 현상이 나타나지 않고, 완전 병렬처리가 가능하여 고속 복호가 가능한 장점을 가지고 있다. 이와 같은 시스템에서 LDPC채널 코딩을 각 파장 대역에 부분적으로 적용함으로써, 주파수 효율 감소 및 데이터 전송률 감소를 완화 할 수 있다.

• Restorative Dentistry and Endodontics
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• 제26권5호
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• pp.387-392
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• 2001

When cavity floor is near the pulp, polymerization of light-activated restorations results in temperature increase. This temperature increase cause by both the exothermic reaction process and the energy absorbed during irradiation. Therefore instating base is required. Most frequently used insulating base is glass ionmer. The purpose of this study was to evaluate intrapulpal temperature changes of glass ionomer according to various curing intensity and curing time. Caries and restoration-free mandibular molars extracted within three months were prepared Class I cavity of 3$\times$6mm with high speed handpiece. 1mm depth of dentin was evaluated with micrometer in mesial and distal pulp horns. Pulp chambers were filled with 37.0$\pm$0.1$^{\circ}C$ water to CEJ. Chromium-alumina thermocouple was placed in pulp horn for evaluating of temperature changes. glass ionomer material was placed in 2mm. total curing time was 40s: continuous 40s, intermittent 20s, intermittent 10s. Glass ionomer material was cured with 300mW/$\textrm{cm}^2$, 550mW/$\textrm{cm}^2$ light curing unit. The results were as follows : 1. Temperature in pulp increased as curing unit power is increased. 2. Temperature in pulp more increased continuous emission than intermittent emission.

• 복식문화연구
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• 제10권6호
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• pp.617-632
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• 2002

The purposes of this study are 1) to classify the consumer group according to clothing purchase store(department store, road shop, discount store, Dongdaemoon & Namdaemoon markets) 2) to analyze the differences between VMD attributes which each consumer group value. The attributes on the VMD are categorized as 5 areas 1) interior 2) show window 3) product display & display change cycle 4) color · light · music · small instrument 5) promotion(POP & salesperson). The data were collected from 238 females students and were analyzed by frequency, percent and X²-test. The results of this study are as fellows . 1) On the attribute of Interior, there were significant differences in terms of flow in a store, rest area, the cleanness of floor, show case, and the merchandise itself. 2) On the attribute of show window, there were significant differences in terms of interst of show window. 3) On the attribute of product display & display change cycle, there were significant differences in terms of display method, and display change cycle. 4) On the attribute of color · light · music · small instrument, there were significant differences in terms of interest of color coordination, luminosity and effect of light, and necessity of music & small instrument. 5) On the attribute of promotion(POP & salesperson), there were significant differences in terms of aid of POP.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.620-622
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• 2004

Mobility of an indoor wheeled robot is affected by adhesion force that is related to various floor conditions. When the adhesion force between driving wheels and the floor decreases suddenly, the robot has a slip state. In order to overcome this slip problem, optimal slip velocity must be decided for stable movement of wheeled robot. First of all, this paper shows that conventional PI control can not be applied to a wheeled robot of the light weigh. Secondly, reposed fuzzy logic applied by the Takagi-Sugeno model for the configuration of fuzzy sets. For the design of Takaki-Sugeno model and fuzzy rule, proposed algorithm uses FCM(Fuzzy c-mean clustering method) algorithm. In additionally, this algorithm controls recovered driving torque for the restrain the re-slip. The proposed fuzzy logic controller(FLC) is pretty useful with prevention of the slip phenomena through that compare fuzzy with PI control for the controller performance in the re-adhesion control strategy. These procedures are implemented using a Pioneer 2-DXE wheeled robot parameter.

• 소음진동
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• 제11권2호
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• pp.276-284
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• 2001

In apartment buildings, floor-impact sound has been regarded as the major source that causes complaints from residents. It is mainly due to the use of light-weight structures and the lack of researches in terms of floor-impact sound. The purposes of this study are analyzing the characteristics of vibration response and sound radiation of 12type void slabs in the improvements void slab by impedance method and finding the fittest improvements void slab on the 12type void slab. The main results of this study are summarized as below: (1) In the $\frac{1}{3}$ octave band level of sound radiation, $\frac{1}{3}$ octave band levels, measured from four-divided improvement void slab(No.8) and eight-divided improvement void slab(No.12), are 10~25 dB lower than that of standard void slab(No.1) in the 1250 Hz. Especially, eight-divided improvement void slab(No.12) is the best void slab in terms of radiation efficiency of sound level. (2) In the correlation relation of acceleration and sound radiation, standard void slab(No.1), four-divided improvement void slab(No.8), SK standard four-hole void slab(No.10), and eight-divided improvement void slab(No.12) are positive correlation relation.