• 환경영향평가
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• 제16권5호
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• pp.319-325
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• 2007

Recently, since the risk on natural disasters is increasing due to abnormal weather such as the global warming, a need for a system on prior review on the influence of disasters has emerged in order to establish a solution by analyzing elements of disaster in advance. However, since the inherently destroying business namely the quarrying business is excluded from the range of subject business of Prior Review System on the influence of disasters, a correction for this is required. In order to actually explore how much risk it contains, actual outflow of soil and flood in the quarrying block where quarrying is being currently carried out was examined and the required undercurrent facility capacity which is also used as a grit chamber was investigated. In addition, by comparing the soil outflow of industrial complexes and golf courses which are current subject businesses of Prior Review on the Influence of Disasters and that of rock mountains relative risk level was examined. After investigation, it was found that the risk on occurrence of disasters was increased due to increase in outflow of soil and flood because of the change of land condition during and after development thus an adequate solution to decrease is required. In addition, after comparison with other business groups it was found that a significantly higher amount of soil is outflown in case of rock mountains thus it was analyzed that a solution to decrease is required. Therefore, a correction is immediately required in order to include quarrying business in the subject business of Prior Review System on the Influence of Disasters.

• Journal of Information Technology Applications and Management
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• 제18권1호
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• pp.55-74
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• 2011

The growth in the use of ubiquitous computing based on mobile services as an enabler to conduct business more effectively has been phenomenal. Technology acceptance model (TAM) has been applied in different contexts to examine a wide range of information technologies (IT). As more and more companies are finding ways to utilize ubiquitous computing based on mobile services, an important issue is to understand what factors will impact the decisions of consumers in adopting the services. Based on TAM with three additional groups of external factors, i.e., service-related factors (ubiquitous access, context awareness) and technology-related factors (perceived security risk, network connectivity) that are theoretically justified as having influence on both perceived usefulness and perceived ease of use which are additionally considered, a research model for the investigated technology acceptance was developed and empirically examined, using responses from more than intended users of ubiquitous computing based on mobile services. The specific purposes of this study are as follows. Firstly, this study is to identify service beliefs considering unique characteristics for ubiquitous services such as perceived ubiquitous access and perceived context awareness. Secondly, this study is to investigate network characteristics beliefs such as perceived security and perceived connectivity. Thirdly, this paper investigates the relationship among variables such as ubiquitous characteristics, network characteristics, behavioral beliefs, and intention to use ubiquitous web services. This study uses a structural equation model to test the research model. The major results of this study are as follows. Firstly, ubiquitous access has a influence on perceived usefulness and perceived ease of use. Context awareness has an influence on perceived usefulness. Secondly, User familiarity has an influence on perceived usefulness and perceived ease of use, and intention to use. User innovativeness has an influence on perceived ease of use. Thirdly, perceived security risk has an influence on perceived usefulness and perceived ease of use. Network connectivity has an influence on perceived usefulness and perceived ease of use. Fourth, there exist differential effects among factors in structural model among information, transaction, and entertainment services.

• 한국수소및신에너지학회논문집
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• 제28권1호
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• pp.56-62
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• 2017

Although most electricity production contributes to air pollution, the vehicle organizations and environmental agency categorizes all EVs as zero-emission vehicles because they produce no direct exhaust or emissions. Currently available EVs have a shorter range per charge than most conventional vehicles have per tank of gas. EVs manufacturers typically target a range of 160 km over on a fully charged battery. The energy efficiency and driving range of EVs varies substantially based on driving conditions and driving habits. Extreme outside temperatures tend to reduce range, because more energy must be used to heat or cool the cabin. High driving speeds reduce range because of the energy required to overcome increased drag. Compared with gradual acceleration, rapid acceleration reduces range. Additional devices significant inclines also reduces range. Based on these driving modes and climate conditions, this paper discusses the performance characteristics of EVs on energy efficiency and driving range. Test vehicles were divided by low / high-speed EVs. The difference of test vehicles are on the vehicle speed and size. Low-speed EVs is a denomination for battery EVs that are legally limited to roads with posted speed limits as high as 72 km/h depending on the particular laws, usually are built to have a top speed of 60 km/h, and have a maximum loaded weight of 1,400 kg. Each vehicle test was performed according to the driving modes and test temperature ($-25^{\circ}C{\sim}35^{\circ}C$). It has a great influence on fuel efficiency amd driving distance according to test temperature conditions.

• Asian-Australasian Journal of Animal Sciences
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• 제25권4호
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• pp.584-591
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• 2012

To evaluate the role of using forage, shade and shelterbelts in attracting birds into the range, three trials were undertaken with free range layers both on a research facility and on commercial farms. Each of the trials on the free range research facility in South Australia used a total of 120 laying hens (Hyline Brown). Birds were housed in an eco-shelter which had 6 internal pens of equal size with a free range area adjoining the shelter. The on-farm trials were undertaken on commercial free range layer farms in the Darling Downs in Southeast Queensland with bird numbers on farms ranging from 2,000-6,800 hens. The first research trial examined the role of shaded areas in the range; the second trial examined the role of forage and the third trial examined the influence of shelterbelts in the range. These treatments were compared to a free range area with no enrichment. Aggressive feather pecking was only observed on a few occasions in all of the trials due to the low bird numbers housed. Enriching the free range environment attracted more birds into the range. Shaded areas were used by 18% of the hens with a tendency (p = 0.07) for more hens to be in the paddock. When forage was provided in paddocks more control birds (55%) were observed in the range in morning than in the afternoon (30%) while for the forage treatments 45% of the birds were in the range both during the morning and afternoon. When shelterbelts were provided there was a significantly (p<0.05) higher % of birds in the range (43% vs. 24%) and greater numbers of birds were observed in areas further away from the poultry house. The results from the on-farm trials mirrored the research trials. Overall 3 times more hens used the shaded areas than the non shaded areas, with slightly more using the shade in the morning than in the afternoon. As the environmental temperature increased the number of birds using the outdoor shade also increased. Overall 17 times more hens used the shelterbelt areas than the control areas, with slightly more using the shelterbelts in the afternoon than in the morning. Approximately 17 times more birds used the forage areas compared to the control area in the corresponding range. There were 8 times more birds using a hay bale enriched area compared to the area with no hay bales. The use of forage sources (including hay bales) were the most successful method on-farm to attract birds into the range followed by shelterbelts and artificial shade. Free range egg farmers are encouraged to provide pasture, shaded areas and shelterbelts to attract birds into the free range.

• 한국지진공학회논문집
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• 제22권3호
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• pp.169-174
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• 2018

A total of 594 reservoirs (17%), which are managed by KRC, equipped with earthquake-resistant facilities whereas remaining ones did not. In addition, reservoirs were placed without the effect of geological structures (i.e., fault and lineament). Therefore, development on technique for alleviating the potential hazards by natural disasters along faults and lineaments has required. In addition, an effective reinforcement guideline related to the geological vulnerabilities around reservoirs has required. The final goal of this study is to suggest the effective maintenance for the safety of earth fill dams. A radius 2 km, based on the center of the reservoir in the study area was set as the range of vulnerability impacts of each reservoir. Seismic design, precise safety diagnosis, seismic influence and geological structure were analyzed for the influence range of each reservoir. To classify the vulnerability of geological disasters according to the fault distribution around the reservoir, evaluation index of seismic performance, precise safety diagnosis, seismic influence and geological structure were also developed for each reservoir, which were a component of the vulnerability assessment of geological disasters. As a result, the reservoir with the highest vulnerability to geological disasters in the pilot district was analyzed as Kidong reservoir with an evaluation index of 0.364. Within the radius of 100km from the epicenter of the Pohang earthquake, the number of agricultural infrastructure facilities subject to urgent inspections were 1,180 including reservoirs, pumping stations and intakes. Four reservoirs were directly damaged by earthquake among 724 agricultural reservoirs. As a result of the precise inspection and electrical resistivity survey of the reservoir after the earthquake, it was reported that cracks on the crest of reservoirs were not a cause of concern. However, we are constantly monitoring the safety of agricultural facilities by Pohang aftershocks.

• 지질공학
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• 제11권1호
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• pp.37-50
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• 2001

서울 근교의 화강편마암지역 지하 석유비축기지 주변 지하수계 모델링 연구를 통하여, 기지 인근에서 지하수를 개발할 때의 영향 및 지하수 개발의 악영향 저감을 위한 수벽공 설치의 효과 등을 파악하고, 실제 설치 후의 영향을 측정하여 모델링 결과와 비교 분석하므로서 기지의 관리 및 운영에 참고하고자 하였다. 심부 지하수를 개발한 경우의 기지 주변의 지하수 유동체계 분석, 그리고 이 개발 위치와 기지 사이에 수벽공을 설치했을 경우의 유동체계를 MODFLOW 수치해석방법으로 분석하였다. 기지 주변 관측공의 실제 지하수위는 EL.+30∼60m 범위에서 변동하며, 모델링 결과는 EL.+20∼50m 범위에서 변동하여 유사한 양상을 보이고 있다. 지하수 개발에 의해 기지 주변의 수위가 하강하였다가 수벽설치 후에 회복되었음을 수치해석을 통해 확인할 수 있었다. 지하지질구조 및 수리지질 요소를 적절히 입력하고 효과적인 모델링 연구를 수행하여 기지의 운영에 기여하였음을 확인하였다.

• 한국콘텐츠학회논문지
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• 제18권9호
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• pp.606-613
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• 2018

이 연구는 범죄에 대응하기 위하여 경찰의 정보활동 중 휴민트에 대하여 살펴보고, 휴민트의 특성을 고려하여 인적네트워크 수준이 휴민트 활용에 미치는 영향을 파악하기 위한 연구이다. 연구의 완성을 위하여 현직경찰을 대상으로 설문조사를 실시하여 얻어진 자료로 연구를 수행하였다. 휴민트는 대인간의 접촉을 통하여 얻어지는 정보를 의미하는 것으로 무형적인 접촉을 통하여 얻어지는 정보를 의미한다. 휴민트는 전달되는 속도가 빠르고, 상대의 은밀한 의도까지 파악할 수 있으며, 접근하기 어려운 정보에 접근할 수 있고, 기계를 사용하지 않는 경우가 많기 때문에 인간의 오감을 이용한 정보획득이 가능한 장점을 가지고 있다. 휴민트는 인간관계를 바탕으로 정보를 획득하는 정보활동으로서 인간관계는 휴민트 획득의 근간이라 볼 수 있다. 따라서, 경찰관의 인간관계를 독립변수라고 할 때 인간관계를 구성하는 인간관계 수준, 인간관계의 신뢰깊이, 인간관계의 폭이 휴민트 활용에 미치는 영향을 살펴본 결과, 인간관계의 폭이 넓을수록 동향을 파악하는데 효과적으로 이용하고 있는 것으로 나타났으며, 범죄에 대응하기 위한 정보를 활용하는 경우에도 인간관계의 폭이 넓을수록 효과적인 것으로 나타났다.

• Ocean and Polar Research
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• 제34권3호
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• pp.325-335
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• 2012

It is well known that sound waves in the sea propagates under the influence of sea surface and bottom roughness, the sound speed profile, the water depth, and the density of sea floor sediment. In particular, an abrupt change of sound speed with depth can greatly affect sound propagation through an eddy. Eddies are frequently generated in the East Sea near the Korean Peninsula. A warm eddy with diameter of about 150 km is often observed, and the sound speed profile is greatly changed within about 400 m of water depth at the center by the eddy around the Ulleung Basin in the East Sea. The characteristics of low-frequency sound propagation across a warm eddy are investigated by a sound propagation model in order to understand the influence of warm eddies. The acoustic rays and propagation losses are calculated by a range-dependent acoustic model in conditions where the eddy is both present and absent. We found that low-frequency sound propagation is affected by the warm eddy, and that the phenomena dominate the upper ocean within 800 m of water depth. The propagation losses of a 100 Hz frequency are variable within ${\pm}15$ dB with depth and range by the warm eddy. Such variations are more pronounced at the deep source near the sound channel axis than the shallow source. Furthermore, low-frequency sound propagation from the eddy center to the eddy edge is more affected by the warm eddy than sound propagation from the eddy edge to the eddy center.

• 한국강구조학회 논문집
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• 제15권2호
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• pp.137-145
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• 2003

본 연구에서는 국산 PS 강봉의 직경, 반복최소응력 및 반복최대응력 등을 실험변수로 하여 직접 인장 피로실험을 수행하였다. 정적 인장실험 결과, 국산 PS 강봉의 응력 - 변형률 곡선과 극한강도 등을 얻었다. 또한, 피로실험에서의 특징적인 실험결과는 PS 강봉의 직경은 피로 수명에 중요한 인자가 아니며, 반복 최소응력의 크기는 국산 PS 강봉의 피로수명에 매우 큰 영향을 미치는 것으로 나타났다. 이러한 피로실험결과를 통계 분석하여 PS 강봉의 응력 범위 및 반복 최소응력 등을 변수로 하는 피로강도 예측식을 제안하였다. 피로실험 중, 시편중앙에 설치한 Extensometer를 이용하여, 변형률의 변화를 측정하였으며, 측정된 변형률 변화현상에서 탄성계수의 변화현상을 구하였다. 변형률 증가현상은 3단계의 형태 즉, 초기에 급격한 증가 후 서서히 증가하며 파괴 직전에 급격하게 증가하는 형태로 나타났다. 탄성계수의 변화현상은 변형률 변화현상과 유사하게 감소하는 것으로 나타났으며 응력수준은 탄성계수 변화에 큰 영향을 주지 않는 것으로 나타났다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 춘계학술대회 논문집 디스플레이 광소자 분야
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• pp.155-158
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• 2000

Influence of sustain pulse-width on electro-luminous efficiency is experimentally investigated for surface discharge of AC-PDP. A square pulse with variable duty ratio and rising time of 300 ns has been used in the experiment. It is found that the firing voltage is decreased as the pulse-width is increased from 2 ${\mu}s$ to 8 ${\mu}s$ with sweeping frequency range of 10 kHz to 50 kHz. It has been found that the optimal sustain pulse-width is in the range of $3{\sim}4{\mu}s$ under driving frequency range of 30 kHz and 50 kHz, based on observation of memory coefficient, wall charge, and wall voltage as well as luminous efficiency.