PURPOSES : This study compared two measures of traffic flow effectiveness on roads with roundabouts and signalized intersections and determined the more appropriate measure. METHODS: In addition to average delay time, the conventionally used measure, average travel time was introduced to measure traffic flow effectiveness because it is able to be obtained through field survey and reflect different travel distances and speed limits of roundabouts and signalized intersections. Using the two measures, roundabouts and signalized intersections were compared through simulations in terms of traffic flow effectiveness. RESULTS : For one-way single-lane roads, the two measures indicated consistent results that roundabouts were more effective than were signalized intersections when the traffic volume was less than 300 vphpl but vice versa when it exceeded 450 vphpl; however, the measures yielded inconsistent results when the volume was 350~400 vphpl. For one-way double-lane roads, the two measures indicated consistent results that roundabouts were more effective than were signalized intersections when the volume was less than 200 vphpl but vice versa when it exceeded 400 vphpl; however, the measures yielded inconsistent results when the volume was 250~350 vphpl. The results obtained using the two measures differed substantially for double-lane roads because behaviors such as weaving and lane changing at roundabouts are more common in double-lane roads than in single-lane roads. CONCLUSIONS : The average delay time would be lower on roads with roundabouts, but average travel time would be lower on roads with signalized intersections. Thus, evaluating the relative effectiveness of roads with roundabouts and signalized intersections by using average delay time alone would be inappropriate, whereas using average travel time as the evaluation index would yield fairer results.

Earthquakes is impossible to predict and occur within very little or no warning. They cause significant damage to property and inflict large human casualties. Seismic retrofit for non-seismic design RC frame has been studied over the years. Although there are many seismic retrofit methods, the seismic retrofit methods are increased weight and physical damage to structures. This study evaluates the seismic performance of RC frame retrofitted with velcro. The specimens were made scale down of actual steel structures, and displacement loads were applied in the trasnverse direction.

강원도 고랭지권(해발 700~1,200m)의 여름배추는 5,140 ha 면적에서 184만 톤 정도가 생산된다(2014). 최근 기후변화, 연작 등의 영향으로 수량성이 조금씩 떨어지고 있는 실정이지만 감자, 무와 더불어 고랭지 농가의 중요한 소득작물이다. 주요 병해충은 뿌리혹병(Plasmodiophora brassicae), 무름병(Pectobacterium carotovorum subsp. carotovorum), 그루썩음병(Pythium ultimum), 밑둥썩음병(Rhizoctonia solani), 배추좀나방(Plutella xylostella), 무잎벌(Athalia rosae ruficornis) 등이다. 고랭지 배추 재배농가의 75%가 포전매매를 하기 때문에 병해충 방제를 위한 농약 의존도가 매우 높아서 매년 7~10회의 농약살포가 이루어지고 있다. 이에 병해충 방제를 위해 경종적, 물리적 및 생물적 기술을 활용하여 고랭지 여름배추의 무농약 재배· 수확을 위한 몇 가지 시험을 수행하였다. 적용한 기술로는 비닐멀칭, 피복작물 도입, 성페로몬 트랩, 황색점착 트랩, 천적 방사, 천적 유인작물 도입, 유기농업자재의 살포 등이다. 본 발표에서는 개별 방제기술에 의한 병해충 방제효과와 이들을 병용했을 때의 효과 및 초래되는 부작용 등에 관해 논하고자 한다. 특히 천적을 유인하고 토양 피복 효과를 가진 개화식물을 배추와 혼작할 경우 좋은 효과를 보였는데, 해충 밀도가 높아지는 경우 천적에 대한 저독성 농자재를 병용하면 해충을 경제적 방제밀도 이하로 유지시 킬 수 있었다.

It has been many efforts for reinforcement of existing structure since the number of earthquake has been increased world widely. Especially the occurrence of earthquake surrounding area of Korean peninsular is dramatically increased. Since the buildings in Korea have not been designed to carry the lateral and shear force caused by earthquake, the building will experience massive damages even under moderate earthquake. For this reason, the viscoelastic damper is proposed in this paper to enhance the earthquake resistance of a steel frame buildings. The viscoelastic dampers have been able to increase the overall damping of the structure significantly, hence improving the overall performance of dynamically sensitive structures. In this paper, Viscoelastic dampers designed are consists of FRP panel and viscoelastic material. In this paper, evaluate the performance of the viscoelastic damper through the experiment.

작물에 발생하는 해충을 생물적으로 방제하는 방법에는 천적의 도입, 천적의 대량방사 및 천적의 보호가 있다. 특히 천적의 보호는 서식처(habitat) 관리를 위주로 실행되는데 윤작체계 도입, 피난처 및 월동처 제공, 천적 유인작물 재배 등이 있다. 천적 기생봉은 활동에 필요한 먹이를 주로 꽃에서 얻는다. 따라서 작물을 재배하는 밭에 천적 기생봉이 선호하는 꽃 피는 작물을 재배하면 천적 기생봉의 유인 및 기생활동의 향상 효과를 볼 수 있다. 이를 위해 고랭지 배추밭 주위에 6종의 꽃 피는 작물을 재배한 후 유인되는 천적과 해충의 종류를 조사하였다. 그 결과 메밀에는 무당벌레(Harmonia axyridis) 등 5종의 천적이 유인되었다. 매리골드에는 꼬마꽃등에(Sphaerophoria menthastri), 별넓적꽃등에(Eupeodes corollae)가 유인되었고, 백겨자에는 배세줄꽃등에(Temnostoma bombylans), 꽃등에(Eristalis tenax), 무당벌레(H. axyridis)가, 잠두에는 무당벌레(H. axyridis), 칠성풀잠자리(Chrysopa pallens)가 각각 유인되었다. 그러나 천적 유인작물 종류별로 해충도 유인되었는데, 배추과에 속하는 백겨자에서 배추좀나방(Plutella xylostella), 무잎벌(Athalia rosae ruficornis), 북쪽비단노린재(Eurydema gebleri), 벼룩잎벌레(Phyllotreta striolata), 장님노린재류 등이 다수 확인되었다. 나머지 유인작물은 배추의 비기주 해충을 유인하였다. 따라서 천적 유인작물의 선발을 위해서는 기주가 중복되는 작물은 피하는 것이 유리하며, 본 실험에서 천적 유인과 해충 격퇴를 동시에 고려할 때 메밀과 매리골드가 효과적인 것으로 판단된다.

노린재목(Hermiptera)에 속하는 물장군(L. deyrollei)은 수서곤충 중 가장 대형 종으로 습지, 논, 농수로 등에서 서식하며 담수어류나 양서류 유생 등을 포식하는 육식성 곤충이다. 본 연구는 2015년 5월부터 7월까지 제주도내 물장군 서식지(서귀포시 성산읍 난산리(A), 신천리(B)) 2곳과 개체수가 줄어드는 서식지(제주시 구좌읍 덕천리(C), 한림읍 상대리(D)) 2곳 및 물장군이 서식하지 않는 습지(한경면 용수리(E))에 서식하는 담수어류 및 양서류 유생을 조사하였다. 조사방법은 각 습지 당 10분씩 포충망을 이용하여 채집을 실시하였다. 조사결과 A습지는 5월에 북방산개구리(Rana dybowskii) 100개체, 6월에 참개구리(R. nigromaculata)와 청개구리(Hyla japonica)가 1개체, 9개체 및 7월에 1개체, 4개체가 조사되었다. B습지는 5월(북방산개구리 100개체), 6월(참개구리 9개체, 미꾸리(Misgurnus mizolepis) 2개체), 7월(참개구리 및 미꾸리가 11개체, 1개체)가 조사되었다. C습지는 5월(북방산개구리 6개체, 참개구리 22개체, 청개구리 38개체, 미꾸리 4개체, 제주도롱뇽(Hynobius quelpartensis) 1개체)가 조사되었고, 6월에 청개구리 4개체, 7월에 참개구리 2개체가 조사되었다. D습지는 5월에 북방산개구리 40개체, 6월에 참개구리, 청개구리, 미꾸리가 각 1개체, 4개체, 10개체가 나타났으며, 7월에는 채집된 개체가 없었다. 마지막으로 E습지에서는 6월에 제주도롱뇽 2개체만 조사되면서 물장군이 서식하는 습지에서는 담수어류 및 양서류 유생의 개체수 및 시기에 따른 종 변화가 다양한 것으로 판단되며, 먹이원이 풍부하지 않거나 7월 이후에 사라지는 습지에서는 물장군이 서식 및 번식하기에는 부적절하다고 사료된다.

노린재목(Hemiptera)에 속하는 물장군(Lethocerus deyrollei (Vuillefroy))은 국내에 서식하는 노린재 중 가장 대형 종으로 민물고기, 양서류 및 양서류 유생 등을 포식하는 종으로 환경부에서 지정한 멸종위기 야생생물 Ⅱ급 보호종이다. 본 연구는 2015년 6월 27일부터 7월 30일까지 광주기가 인공 부화된 물장군의 생장에 미치는 영향을 평가하기 위해 30℃, 광주기 12L:12D, 8L:16D 조건에서 80개체를 대상으로 2회 반복 실험을 실시하였다. 조사 결과 12L:12D에서는 각 령기별 생장 기간이 3.54일(1령), 3.1일(2령), 3.5일(3령), 5.03일(4령), 11.18일(5령)로 총 26.35일이였고, 8L:16D에서는 3.8일(1령), 3.5일(2령), 4.14일(3령), 5.77일(4령), 12.40일(5령)로 총 29.61일로 나타내어 12L:12D조건이 8L:16D조건보다 88.99%로 생장 기간이 짧은 것으로 판명되었다.

감자를 기주로 하는 진딧물은 복숭아혹진딧물(Myzus persicae), 감자수염진딧물(Macrosiphum euphorbiae), 싸리수염진딧물(Acyrthosiphon solani), 목화진딧물(Aphis gossypii), 무테두리진딧물(Lipahis erysimi), 조팝나무진딧물(Aphis citricola) 등이며, 특히 복숭아혹진딧물, 감자수염진딧물, 싸리수염진딧물은 감자의 잎말림바이러스(PLRV)를 영속적으로 옮기는 대표적인 매개충이다. 우리나라의 씨감자 재배단지인 강원도 평창 대관령지역(해발 800m)에서 유시성충의 비래는 4월말~5월초에 시작되며, 이 시기는 평난지 채소작물의 생육중기에 해당되고, 여기서 바이러스를 획득한 유시성충이 대관령지역으로 비래한다. 따라서 평난지 채소작물의 종류, 재배시기와 재배면적, 진딧물 방제여부 등에 따라 비래진딧물의 종류와 비래량 및 바이러스 보독률도 변동하게 된다. 최근 온난화에 따른 진딧물의 비래 동향을 5~10년 이동평균값을 분석한 결과 과거 대비 최근의 비래밀도가 유의적으로 증가하는 것으로 나타났다(R2=0.656 및 0.775). 유시 진딧물의 비래 최성기(4~6월)를 기준으로 날아오는 비래량은 과거 대비 확연한 증가 추세를 확인할 수 있었다. 진딧물 비래량이 평년 대비 폭증한 연도는 1985년, 1994년, 2001년, 2009년, 2014년이었다. 특히 2009년의 털진딧물(Chaitophorinae sp.)과 2014년 병진딧물(Rhopalosiphoninus sp.)의 대량발생이 특이하였는데, 이는 이상고온 현상과 밀접한 연관이 있는 것으로 추정된다.

The aim of this study was to evaluate the chemical quenching system for residual ozone and to determine the operating condition for the quenching system. Hydrogen peroxide (H₂O₂) and sodium thiosulfate (Na₂S₂O₃) were investigated as quenching reagents for ozone removal, and the tendency of each chemical was notably different. In the case of H₂O₂, the degradation rate of ozone was increased as the concentration of H₂O₂ increase, and temperature and pH value have a significant effect on the degradation rate of ozone. On the other hand, the degradation rate of ozone was not affected by the concentration of Na₂S₂O₃, temperature and pH value, due to the high reactivity between the S₂O₃²- and ozone. This study evaluates the decomposition mechanism of ozone by H₂O₂ and Na₂S₂O₃ with consideration for the water quality and reaction time. Furthermore, the removal test for the quenching reagents, which can be remained after reaction with ozone, was conducted by GAC process.

Since it is impossible to predict earthquakes, they involve more casualties and property damage compared to meteorological disasters such as heavy snow and heat waves, which can be predicted through weather forecasts. This has highlighted the need for seismic design and reinforcement. Recently, the use of composite materials as reinforcement has surged because steel plate reinforcement and section enlargement are likely to result in increased weight and physical damage to structures. This study evaluates the seismic performance of panels created from composite materials, and their guide systems. The specimens were miniature versions of actual steel structures, and displacement loads were applied in the transverse direction. Seismic performance was found to improve when structures were reinforced with seismic panels.

Compared to steel of the same weight in steel concrete structures, fiber reinforced polymer (FRP) is known to have greater strength and better resistance to corrosion. As such, it is being proposed as an effective structural material. Despite its many advantages, FRP has not been rapidly adopted in civil structures. This is because it is more expensive, prone to brittle fracture, and has weak fire resistance. To examine changes in the mechanical properties of FRP and the effectiveness of fire resistant coating, this study conducted tensile tests on coated and uncoated specimens over varying temperature. Glass fiber has excellent fire resistance since it does not melt or burn at high temperatures. However, epoxy is unable to withstand exposure to temperatures exceeding the transition temperature, thus leading to unsatisfactory structural performance and fire resistance. This study investigated the behavioral changes in FRP by exposing the specimens to temperatures ranging from room temperature (approx. 25℃) to 300℃, so as to improve the fire resistance of epoxy.

Because earthquakes occur within very little or no warning, they cause significant damage to property and inflict large human casualties. Seismic design and reinforcement has been extensively studied over the years, for the purpose of reducing damage from earthquakes. Composite materials are being widely used as reinforcement because the use of steel plates and section enlargement are time-consuming methods that leave physical damage to structures. This study assessed the guide system performance of FRP panels created from composite materials. Actual steel structures were reproduced in miniature form, and were subjected to transverse displacement loads. The experiments were carried out by applying two types of FRP panel guide systems to the specimens.

This study is a part of high strength lightweight aggregate concrete researches using lightweight aggregates and the purpose of this study is to find out the basic physical characteristics and tension cracking fracture characteristics of lightweight concrete. Crack Mouth Opening Displacement is measured through three point flexure experiment about embellish notch beam. Load-CMOD characteristics are examined through rules of countries, characteristics of lightweight concrete and tension cracking fracture experiments. The degree of tensile characteristic alteration according to size changes of specimen and the characteristics about crack surface are analyzed. The changes of softening curve are analyzed and fracture energy is drawn through inverse analysis by the obtained Load-CMOD curve. To decide fracture energy and analysis parametric, inverse analysis is conducted and Ant Colony Method is conducted for optimization and then a way to find out optimal parameterization fracture energy is suggested.

The need to consider torsion in the design of members of a structure has recently been increasing; therefore, many studies on torsion have been carried out. Recent research was focused on the torsional performance of concrete according to the reinforcing materials used. Of particular interest, are torsion studies of beams made of SFRC(steel fiber reinforced concrete), and there has been increasing use of SFRC at construction sites. In contrast, research on the composite PVA-ECC (polyvinyl alcohol-engineered cementitious composite) has only covered its mechanical performance, though it exhibits excellent tensile-strain performance (better than SFRC). Therefore, research on the torsion of concrete beams retrofitted using PVA-ECC is lacking. In this study, the behavior characteristics and performance of reinforced-concrete beams retrofitted by PVA-ECC was investigated experimentally. The experimental results show that the resistance to torsional cracking is increased by PVA-ECC. In addition, the strain on the rebar of the specimen was found to be reduced.