• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2000년도 창립총회 및 춘계학술발표회
• /
• pp.28-32
• /
• 2000

There are many different chemical pollutants that originate from atmospheric deposition and transportational activities along roads. This paper review the characteristics of heavy metal pollution, relationships between land use and pollutant load in urban area. Four land use areas in Seoul were selected for sampling and study with different characteristics during the period from April 1998 and February 2000. A series of studies have been carried out concerning the physicochemical characteristics of the sediments settling down in a gully pot to evaluate the contamination for heavy metals. The sediment samples from gully pots were characterized by the chemical extraction experiments. Sediments are characterized by very high concentrations of heavy metals, probably because of a long-term accumulation of vehicle- and industrial-related pollutants. The characteristics of heavy metal pollution show that each land use has different sources of contaminations. Mean Zn concentration in Yeouido and Junggu areas is 2-3 times higher than those in Dobonggu area. This suggests that Zn may be derived from the source of automobile traffic. The mean concentrations of Cu and Cr are very significantly high in Junggu and Gurogu areas and indicate that the industrial activities may contribute to the accumulation of Cu and Cr in sediments. The low Pb levels throughout the whole study areas in Seoul can be accounted for the use of unleaded gasoline since 1987.

• Water Engineering Research
• /
• 제4권4호
• /
• pp.187-192
• /
• 2003

The rainfall observation systems have largely been improved in Japan. The Japan Meteorological Agency, prefecture governments, and other administrative bodies have also increased the number of rain gauges thru out the country. The density of observatories is now one per several $\km^2$. Heavy rainfall information systems have been improved. Besides it, the Internet was popularized in the late 1990s, and has been used to transmit data of heavy rainfall. Internet accessible cellular phones have been popular in Japan since 1999. Such phones are expected to be useful in the field of disaster warning announcements, because they can automatically notify users bye-mail of pending disasters. The use of the Internet during natural disasters is groundbreaking in Japan today. However, in order to use disaster information effectively on Internet it is necessary to investigate how to use the information during the rainfall disaster. Therefore in our study we suggest methods on the effective construction and their use of information technology on Internet.

• Nuclear Engineering and Technology
• /
• 제50권1호
• /
• pp.80-87
• /
• 2018

Consideration is given to the possibility to use changes in buoyancy as a negative reactivity feedback mechanism during temperature transients in heavy liquid metal fast reactors. It is shown that by the proper use of heavy pellets in the fuel elements, fuel rods could be endowed with a passive self-ejection mechanism and then with a negative feedback. A first estimate of the feasibility of the mechanism is calculated by using a simplified geometry and model. If in addition, a neutron poison pellet is introduced at the bottom of the fuel, then when the fuel element is displaced upward by buoyancy force, the reactivity will be reduced not only by disassembly of the core but also by introducing the neutron poison from the bottom. The use of induced buoyancy opens up the possibility of introducing greater amounts of actinides into the core, as well as providing a palliative solution to the problem of positive coolant temperature reactivity coefficients that could be featured by the heavy liquid metal fast reactors.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2004년도 추계학술대회논문집
• /
• pp.97-102
• /
• 2004

The Characteristics of noise and vibration by heavy-weight floor impact sound was studied. Resonance frequency increased a little in structures that use damping material in living room and bedroom, and acceleration waves length that respond became short, and displayed aspect that oscillation level decreases. Result that measure sound pressure level, structure that compare and applies damping materials with structure that apply the resilient materials from 63Hz lower part that impact energy is concentrated in energy spectrum of heavy-weight floor impact sound displayed result that sound pressure, level decreases remarkably. Therefore, according to use of damping materials, confirmed reduction effect of heavy-weight floor impact sound.

• 디지털콘텐츠학회 논문지
• /
• 제16권3호
• /
• pp.493-501
• /
• 2015

본 연구는 상호작용성이 가장 두드러진 디지털콘텐츠 중 하나인 모바일 게임 이용자 속성과 모바일 게임 이용 행태의 상관관계에 대하여 탐색한다. 게임 이용 행태에 영향을 끼치는 다양한 요인 중 이용자 자체의 속성에 주목하고, 이용자의 개인적, 심리적 속성이 실제 게임 이용에 미치는 영향을 살펴보았다. 이용자 속성은 크게 '대인관계, '게임 숙련도, '혁신 성향, '자아존중감, '경쟁심'의 다섯 가지 요인으로 구분하였으며 게임 이용 행태는 크게 두 가지로 나누어 정량적인 행태인 '이용량(이용시간, 소비비용)'과 정성적인 행태인 '지각된 만족도(지각된 즐거움, 지각된 서비스 품질, 지각된 가격)'로 구분하였다. 연구 결과 대체적으로 본 논문에서 상정한 이용자 속성이 강할수록, 이용량과 지각된 만족도가 증가함을 알 수 있었다. 본 연구는 어떠한 속성을 가진 이용자가 더 많이 게임 콘텐츠를 이용하고, 소비하고, 만족하는가를 살펴봄으로써 기존 디지털 콘텐츠의 이용 행태 및 중(重)이용에 관한 연구에 기여하고자 한다.

• 디지털융복합연구
• /
• 제20권3호
• /
• pp.431-438
• /
• 2022

Virtual Reality(이하 VR) 산업은 4차 산업혁명 관련 기술의 발달과 함께 빠르게 확대되고 있으며, 게임 산업에서 가장 많이 활용되고 있다. 한편, 중(重)이용자 집단은 상대적으로 특정 미디어나 콘텐츠를 많이 소비하는 집단으로 미디어 산업의 핵심 고객층이나 아직까지 관련 연구는 부족한 실정이다. 본 연구는 실증연구를 통해 VR게임 내 중(重)이용자 집단의 지속적 이용 의도에 미치는 영향 요인을 알아보고, 경이용자 집단과 변수 차이를 검증해 특성을 파악했다. 연구 결과, 중이용자는 개인 혁신성, 프레즌스, 지속적 이용 의도 변수 측면에서 경이용자보다 높은 이용 행태를 보였다. 또한, 중이용자의 개인 혁신성, 지각된 품질, 프레즌스는 지속적 이용 의도에 유의미한 영향을 미치는 것으로 나타났다. 본 연구를 통해 VR 게임 내 중이용자의 특성과 영향 요인을 실증적으로 분석하여 VR 게임 개발 및 관련 연구의 기초자료를 마련하고자 한다.

• 대기
• /
• 제20권2호
• /
• pp.131-151
• /
• 2010

This study establishes a conceptual model to analyze heavy rainfall events in Korea using multi-functional transport satellite-1R satellite images. Three heavy rainfall episodes in two major synoptic types, such as synoptic low (SL) type and synoptic flow convergence (SC) type, are analyzed through a conceptual model procedure which proceeds on two steps: 1) conveyer belt model analysis to detect convective area, and 2) cloud top temperature analysis from black body temperature (TBB) data to distinguish convective cloud from stratiform cloud, and eventually estimate heavy rainfall area and intensity. Major synoptic patterns causing heavy rainfall are Changma, synoptic low approach, upper level low in the SL type, and upper level low, indirect effect of typhoon, convergence of tropical air in the SC type. The relationship between rainfall and TBBs in overall well resolved areas of heavy rainfall. The SC type tended to underestimate the intensity of heavy rainfall, but the analysis with the use of water vapor channel has improved the performance. The conceptual model improved a concrete utilization of images and data of satellite, as summarizing characteristics of major synoptic type causing heavy rainfall and composing an algorism to assess the area and intensity of heavy rainfall. The further assessment with various cases is required for the operational use.

• International Journal of Concrete Structures and Materials
• /
• 제7권2호
• /
• pp.111-117
• /
• 2013

Heavy oil fly ash (HOFA) is a byproduct generated by the burning of heavy fuel oil. Chemical analysis showed that HOFA is mainly composed of unburned carbon with a significant amount of heavy metals. Due to toxicity, management of this waste poses a challenge to the industry personal. The present study investigates the possible use of HOFA as a black pigment or admixture in cement mortar aiming to produce ornamental brick. In order to investigate the change of cement mortar strength when HOFA is added, the standard compressive strength test with 50 mm cubes was performed. The results showed that the addition of 2-5 % of HOFA in cement mortar does not affect its strength. The leaching behavior of trace elements within HOFA and HOFA mixed mortar were investigated through laboratory batch leaching experiments. The results confirmed that HOFA can be utilized as a black pigment in ornamental brick, which is environmentally safe and provides good balance between color and brick properties.

• 대한방사선기술학회지:방사선기술과학
• /
• 제23권1호
• /
• pp.91-96
• /
• 2000

This work was on the reduction of exposure dose and contrast improvement by Use of Heavy Elements Filter From the result of experimental evaluation, it was found that the beam harding of X-ray was not showed in Ho and Gd, heavy elements filters, contrast to Cu and Al filters In which the harding showed. And the ratio of transit dose to surface dose and the load of X-ray tube increase in order of Al, Cu, Gd and Ho, respectively. The contrast of X-ray images using the intensifying screen and the input phosphor showed the higher value in order of Cu, Al, Gd and Ho. Therefore, in the case of using contrast media and phosphor in region of diagnostic radiology, X-ray image quality depends primarily on kVp and heavy elements filters.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2018년도 춘계 학술논문 발표대회
• /
• pp.195-196
• /
• 2018

The Research is underway to utilize heavyweight concrete for various applications. One of them is to use heavy concrete as a marine concrete such as a breakwater to resist wave. Marine concrete is often complex in shape and requires high fluidity. When the heavyweight concrete is high fluidity, there is a high risk of segregation due to the high density of the coarse aggregate. Therefore, we evaluate the fluidity of heavyweight concrete using heavy fine aggregate. As a result of the fluidity evaluation of the heavyweight concrete, the fluidity of the heavy fine aggregate was similar to that of ordinary concrete. Therefore, it is considered that the use of heavy fine aggregate in the development of high fluidity heavyweight concrete will be one of the methods.