• The Journal of the Korea Contents Association
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• v.19 no.10
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• pp.179-189
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• 2019

Korea's transportation paradigm is shifting from a vehicle-centered to a pedestrian-oriented society. Therefore, the interest in pedestrian safety and the improvement of pedestrian environment is also increasing. However, the level of traffic safety in Korea is still severe. It is needed to improve pedestrian safety and pedestrian environment. This study studied pedestrian-vehicle accident data provided by the Traffic Accident Analysis System(TAAS) for 2013-2015 to build a safe walking environment around school zones, and the relation between the school zones and pedestrian-vehicle traffic accidents were identified through the geographic information system(GIS) and spatial regression model. The main results are as follows. First, both road and public transportation factors are likely to increase pedestrian traffic accidents in school zones. Second, regarding land-use factors, residential, commercial, and industrial areas are found to increase pedestrian traffic crashes. On the other hand, mixed use is likely to play a role on the reduction of pedestrian traffic accidents. Finally, it has been shown that high development density also has a positive effect on pedestrian traffic accidents in school zones.

• Journal of the Korean Geotechnical Society
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• v.25 no.10
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• pp.99-110
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• 2009

In order to provide the design criteria, the characteristics of consolidation for soft ground improvement have been investigated using the field banking test performed by the vertical drain method at the northern container section in Busan New Port. Field test results indicated that the estimated degree of consolidation in design stage decreased by about 7% compared with the measured one. This difference is attributed to the fact that the conservative geological properties were applied with relatively high amount of maximum clay mixture ratio during the design stage. Based on this findings, another laboratory oedometer test was implemented to consider various combination of mixture ratio. It was found that the consolidation degree increased in accordance with the increase of sand/silt mixture ratio. Also, the proportion of 10%, 50%, and 40% for sand, silt, and clay, respectively, was observed as the best combination of mixture ratio to the actual measurement, which is very similar to the average grain size distribution in the banking test area. Therefore, it is suggested that the overall geological characteristics as well as the grain size distribution should be considered in design stage to improve the soft ground that contains mixture of sand, silt, and clay.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.6
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• pp.442-450
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• 2011

A three dimensional random walk particle tracking method is applied to the Saemangeum area in order to find stepwise environmental changes according to long term construction. Flow regime around Mangyeong, Dongjin and Geum river estuary changed greatly due to dike construction. It is distinctive that reduction of Byeonsan area's flow field and stagnant change in the northern part of the inner reservoir. Similar characteristics are found through the tidal excursion analysis. By analysis of the vertical mixing structures according to density stratification based on temperature and salinity variation, a salt wedge and very strong stratification arises in the inner part of the reservoir after final closure, while it has been well mixed or partially mixed estuary during construction. Shrinking of horizontal dispersion and vertical mixing capability may cause adverse effect on water quality not only inner part but also outer region of the Saemangeum reservoir.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1999.06a
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• pp.93-98
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• 1999

톨루엔, o-크실렌등의 유기용제는 도료공업 등의 혼합용제와 기계부품의 세척등에 많이 사용되고 있다. 그러나 이들 물질들은 공정상의 제조, 저장, 처리과정 및 취급과 사용 중에 부주의로 인한 밀폐구역에서의 누출로 폭발과 화재사고가 자주 발생하고 있다. 97년 5월 $\Delta$$\Delta$조선소에서 건조 중이던 선박 기관실의 선체 탱크내부 도장작업 중 화재ㆍ폭발이 발생하였으며, 97년 10월 $\square$$\square$조선소에서 수리중이던 유조선의 Tank 내부와 pipe line에 체류중인 가연성 증기가 인화되어 화재ㆍ폭발사고가 98년 6월 김해시 소재 00공업(주)에서 솔벤트로 공작기계 부품을 세척하던중 가연성 증기가 인화되어 화재가 발생하였다. (중략)

• The Korean Journal of Quaternary Research
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• v.10 no.1
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• pp.27-52
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• 1996

금강 퇴적물의 지화학적 특성을 파악하기 위하여 상류에서 하류까지 21개의 표층 퇴적물을 채취하고 총금속(Al, Fe, Mn, Cr, Co, Ni, Cu, Zn, Pb) 입도별 금속 및 존재형태별 금속을 분석하였다. 또한 하천에서 연안역까지 미량금속의 공간적 변화를 보기 위해 부유물 을 일정 간격으로 채취하여 미량금속을 분석하였다. 퇴적물 중 미량 금속 함량을 평균 입도 와 밀접히 관계하여 변화하며 세립질실트 이하 부분에서 가장높은 함량을 보였고 이 높은 함량은 하천 부유물 중 금속 함량과 Mn을 제외하고 거의 유사한 수준이었다. Pb은 조립질 모래에서도 높은 함량을 보이는데 이는 조립질 모래에 많이 포함된 정장석에 의한 영향이 되고 세립질 실트에서의 높은 금속 함량은 세립한 중광물에 의한 영향이다. Mn과 Pb을 제 안한 금속들은 퇴적물 중 주로(70% 이상) 결정 격자와 관계하여 존재하는데 이는 퇴적물의 주구성 입도가 조립하여 금속이 풍부하고 세립한 중광 물에 의한 영향이 크기 때문이다. 하 천에서 염하구로 금속 함량이 급격히 감소하는데 이는 용존 $Mn^{+2}$이온이 $MnO_2$로 변화하는 산화반응과 하천구역에서의 퇴적 그리고 염하구에서 금속이 적어 진 입자(염하구 내에서 유기물 분해/용해로 만들어지거나 재부유 작요에 의한 조립질 물질) 와 하천 부유물과의 혼합작용에 의해 이루어진다.

• The Korean Journal of Malacology
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• v.7 no.1
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• pp.30-48
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• 1991

한국해역 종합 해양자원도 작성연구(남해)의 일환으로 저서생물 분포 연구를 위한 조사가 1990년 7월과 8월에 남해에 위치한 83개 조사정점에서 수행되었다. 각 정점에서 van Veen그랩으로 3회씩 채집된 저서 생물 표본 가운데 연체동물만을 선별 그들의 분포 양상을 파악하고자 종 동정과 함께 군집구조 분석을 하였다. 조사에서 채집된 연체동물은 모두 679개로 다섯개 강에 102종으로 동정되었으며, 이매패류가 출현종수(84.3%)에서나 출현개체수(92.3%)에 있어서 절대우점하였다. 전체 연체동물군집에서 우점하는 일곱 종(이매패류 여섯 종, 무판류 한 종)이 전체 출현개체수의 61.0%를 차지하였다. 남해의 연체동물은 종은 다양한 반면에 서식밀도나 생물량은 매우 빈약하였다. 출현종의 서식 유무에 따른 유사도로써 집괴분석한 결과 다섯개의 조사정점군으로 나누어지고, 이 들은 특징적인 분포 특성을 갖는 두 정점군과 혼합된 특성을 나타내는 세정점군으로 대별되었다. 전자의 두 정점군은 Raetellops Pulchella와 Periploma otohimeae로 대표되는 황해의 저층냉수의 영향을 받는 세립퇴적물 군집과 뚜렷한 대표종은 없지만 대마난류의 영향을 받는 이질성의 조립퇴넉물 군집으로 정의할 수 있었다. 대마난류의 영향을 받는 정점군의 군집은 황해저층냉수의 정점군에 비해 종 다양도는 높지만, 서식생물량은 현저히 적었다. 아울러 연체동물의 분포와 남해의 퇴적환경이나 수괴의 조성과 변화를 고려하여 남해에 서식하는 저서생물 군집에 있어서 네 개의 분포구역이 있을 것으로 추정하여 그 범위와 경계를 제안한다.

• Nuclear Engineering and Technology
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• v.7 no.4
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• pp.277-284
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• 1975

A result of measurement for the relative dose distribution of neutron gamma mixed radiation field in the biological irradiation facility installed at TRIGA Mark-III reactor is described. The relative dose distributions of neutron-gamma mixed radiation field in the biological exposure room have been experimentally determined using a thermoluminescent dosimeter. Presented herein in graphical forms are the experimental results obtained. It as observed that the region commonly having the characteristics of rather homogeneous horizontal and lateral dose distributions is confined to the area bounded by the two planes horizontally parallel to the beam direction with heights of about 40 cm and 130 cm, respectively, at distances beyond 100 cm from the segmentary surface of the aluminum pool liner projected into the the exposure room, while other areas show a steeper gradient in dosage, especially the places adjacent to the segment of the aluminum pool liner and near the inner po${\gamma}$lion of the concrete walls of the exposure room.

• Journal of Korea Water Resources Association
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• v.36 no.4
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• pp.547-559
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• 2003

In this study, a mathematical model is developed for sewer rehabilitation planning by considering cost and inflow/infiltration. A sewer rehabilitation planning model is required to decide the economic life of the sewer by considering trade-off between cost and inflow/infiltration. And it is required to find the optimal rehabilitation timing, according to the cost effectiveness of each sewer rehabilitation within the budget. To solve the problem, we formulated a multiple objective mixed integer programming(MOMIP) model based on network flow optimization. The network is composed of state nodes and arcs. The state nodes represent the remaining life and the arcs represent the change of the state. The model considers multiple objectives which are cost minimization and minimization of inflow/infiltration. Using the multiple objective optimization, the trade-off between the cost and inflow/infiltration is presented to the planner so that a proper sewer rehabilitation plan can be selected.

• Journal of the Korean GEO-environmental Society
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• v.22 no.6
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• pp.27-32
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• 2021

Due to heavy rainfall and typhoons caused by climate change, it has become common to witness heavy rain that exceeds the design frequency of agricultural reservoirs. This has brought greater attention to the safety of irrigation facilities including agricultural reservoirs. Out of approximately 17,740 reservoirs available in Korea, 83.87% were built before 1970. To ensure the safety of these old reservoirs, their embankments are being repaired and reinforced using various techniques. Among these techniques, using the cement-bentonite cutoff wall makes it possible to construct diaphragm walls with slurry composed of cement and bentonite, while excavation. The advantages of this technique include that it is simple and fast, and ensures the uniformity of cutoff walls by enabling the immediate application of the replacement method to excavation areas; thus excellent performance is guaranteed. However, despite these advantages, the technique is not commonly used in Korea. Thus, this study investigated the changes in strength and permeability by varying the mix ratio of cement and bentonite. As a major experimental results, when the cement of 200 kg/m³ and the bentonite of 60 to 80 kg/m³ is most suitable for the repair and reinforcement of the reservoir embankments.

• 한국해양학회지
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• v.25 no.1
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• pp.1-7
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• 1990

Seawater temperature, salinity, inorganic nutrients and the standing crop of phytoplankton species of the 841 water samples from the upper 125 m at 15-40 stations on the 6 semiannual cruises in the southwestern waters of the East Sea (Korea) were studied during the period from September, 1981 to October, 1984, Among the 235 taxa identified two pennate diatioms, cylindrotheca closterium and Nitzschia delicatissima, were the most common and dominant species. The multiple regression analyses between net phytoplankton abundance (dependent variable) and associated environmental factors(independent variables) were applied to the samples from the surface mixed-layer. In spring the coefficients for the seawater temperature was 1. to 4.2 times greater than those for salinity, while the coefficients for the salinity was 2.1 to 3.4 times greater than those for seawater temperature in autumn. Distribution seawater temperature in spring, and salinity in autumn. Schematically the zone of high standing crops moved about on the T-S diagram in a cyclic manner. The distribution of phytoplankton standing crop was quite closely associated with the hydrographic conditions among various kinds of environmental factors studied.