• Korean journal of applied entomology
• /
• v.46 no.1 s.145
• /
• pp.153-158
• /
• 2007

This study was conducted to develope the observing methods for density of stink bugs in soybean reproductive stage. The adults and nymphs of bean bug, Riptortus clavatus, red-banded shield bug, Piezodous hybneri, green stink bug, Nezara antennata, Sole bug, Dolycoris baccarum, and brown marmorated stink bug, Halyomorpha halys were observed by three observing methods such as beating, sweeping net, and visual counting methods in the full bloom (R2), full pod (R4) and beginning maturity (R7) of soybean. As a result, total number of stink bugs observed was the highest with 5,214.2 by beating method, and then was 2,581.8 by visual counting method, and was the lowest with 103.1 by sweeping net method. Total number of stink bugs observed by the beating and visual counting methods was P. hybneri, followed by N. antennata, H. halys, R. clavatus and D. baccarum with clear difference in observed number of each stink bugs while total number of stink bugs observed by sweeping net method was very low in the range of 18 to 23. Accordingly, the observed density of stink bugs exception of R. clavatus adult by beating method was generally high. However, the number of R. clavatus adult was more observed by flushing method than that by beating method from the beginning bloom (R1) to full maturity (R8), and was more observed at morning time than that at afternoon time. Therefore, two observation methods that flushing method for R. clavatus and beating method for the other stink bugs were recommended for the occurring density of stink bugs in soybean because both bean bug and pentatomidae stink bugs have distinct behavior characteristics such as flying and dropping.

• Journal of the Speleological Society of Korea
• /
• v.5 no.6
• /
• pp.20-22
• /
• 1980

동굴 속이라는 특수환경 속에 사는 동물을 우리는 동물생물(Gavernicole)이라 부르며, 이 동굴생물은 i)외래성(trogloxene) : 개구리(Amphibia) 따위의 양서류와 파리(Piptera) 등. ii) 호동굴성(troglophile) : 푸라나니아(Tricladia), 거미류(Araneido) 박쥐(Chirptera) 등. iii) 진동굴성(troglobiont): 새우류(Amphipoda), 톡톡이(Collembala), 좀류(Thysanura), 노래기(Aiplopada) 등. 3가지로 분류하고 있다.(중략)

• Journal of Korean Society of Transportation
• /
• v.28 no.3
• /
• pp.157-167
• /
• 2010

Density is the most important congestion indicator among the three fundamental flow variables, flow, speed and density. Measuring density in the field has two different ways, direct and indirect. Taking photos with wide views is one of direct ways, which is not widely used because of its cost and lacking of proper positions. Another direct density measuring method using two point detectors has been introduced with the concept of instantaneous density, average density and measurement interval. The relationship between accuracy and measurement interval has been investigated using the SIMULATION data produced by Paramics Application Programming Interface function. We analyze the affect of segment density accuracy by sensing gap each road condition such as sensing segment length, lane and LOS after gathering data by Paramics Application Programming Interface.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2016.05a
• /
• pp.477-477
• /
• 2016

하천 내 식생에 의한 유속차이는 활발한 에너지 교환에 기인하며 하천 내 흐름 변화에 큰 변화를 가져온다. 또한 식생에 의한 하천 침식과 퇴적의 반복은 하천 지형 변화의 대표적인 원인 중 하나이다. 따라서 본 연구에서는 소하천을 대상으로 관목류(버드나무류)를 식재하여 식생유무 및 밀도 차이에 대한 흐름패턴 및 유속 변화를 분석하였다. 식생은 고밀도(식생 수 : $38/m^2$)와 저밀도(식생 수 : $10/m^2$)로 구분하였으며 유속 측정은 ADCP와 micro-ADV를 이용하여 비교하였다. 실험 유량은 식생 침수 정도에 따라 부분침수($0.5m^3/s$), 완전침수($3.7m^3/s$)로 나누어 실험을 수행하였다. 실험결과 ADCP와 ADV에 의한 유속값은 유사하게 나타났으며 고밀도일수록 식생에 의한 항력으로 인해 느린 흐름을 보였다. 또한 부분침수 시 식생 내 수심 증가로 인한 흐름 변화가 발생하였으며 완전침수 시에도 식생 유무 및 밀도에 따라 흐름 패턴이 바뀌는 것으로 나타났다. 향후 이 연구는 하천 침식 등을 고려한 수목식재 계획 수립에 기초자료로 사용될 수 있으며 다양한 식생을 대상으로 조도계수 변화, 흐름특성 분석 등이 추가적으로 연구되어야 할 것으로 판단된다.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.31 no.6D
• /
• pp.779-784
• /
• 2011

Freeway FFS (Free-Flow Speed) under the state of LOS (Level of Service) A has been regarded as a homogeneous state to all levels of traffic volume. The features of low-density FFS is served as the basic data for a decision on limited maximal speed, accident analysis, simulation modeling etc. A few researches for the macroscopic characteristics of design and operation speed have been reported, and any study for the microscopic features of freeway free-flow speed under the state of low density has not been done. Therefore, the characteristics of low-density FFS according to the level of traffic volume (1-3 veh/30 sec) and daily hour periods (0-5, 6-8, 9-11, 12-19, 20-23) is microscopically analyzed in this study with huge volume and speed data. It was found that speed distributions are changed and show different behaviors under the conditions of traffic volume levels and daily time periods. V85s (85th percentile speed) at early morning and night periods decrease when levels of traffic volume increase, whereas V85s at day time do not show considerable differences. Especially, FFSs of levels of traffic volume at early morning and night periods, despite low density, is analyzed as heterogeneity, but homogeneity at day time.

• Journal of Korea Water Resources Association
• /
• v.41 no.12
• /
• pp.1187-1198
• /
• 2008

Many reservoirs in Korea and their downstream environments are under increased pressure for water utilization and ecosystem management from longer discharge of turbid flood runoff compared to a natural river system. Turbidity($C_T$) is an indirect measurement of water 'cloudiness' and has been widely used as an important indicator of water quality and environmental "health". However, $C_T$ modeling studies have been rare due to lack of experimental data that are necessary for model validation. The objective of this study is to validate a coupled three-dimensional(3D) hydrodynamic and particle dynamics model (ELCOM-CAEDYM) for the simulation of turbid density flows in stratified Daecheong Reservoir using extensive field data. Three different groups of suspended solids (SS) classified by the particle size were used as model state variables, and their site-specific SS-$C_T$ relationships were used for the conversion between field measurements ($C_T$) and state variables (SS). The simulation results were validated by comparing vertical profiles of temperature and turbidity measured at monitoring stations of Haenam(R3) and Dam(R4) in 2004. The model showed good performance in reproducing the reservoir thermal structure and propagation of stream density flow, and the magnitude and distribution of turbidity in the reservoir were consistent with the field data. The 3D model and turbidity modeling framework suggested in this study can be used as a supportive tool for the best management of turbidity flow in other reservoirs that have similar turbidity problems.

• Water for future
• /
• v.31 no.3
• /
• pp.140-141
• /
• 1998

• 한국해양학회지
• /
• v.25 no.1
• /
• pp.36-48
• /
• 1990

This study was carried out to obtain some informations on the species composition and distribution pattern of Polychate community on the continental shelf and slope area in the East Sea. Fauna samples were collected from three sampling cruises in April of 1985, and April and October of 1987. Total 112 polychaete taxa included in 36 families were collected. Dominant species in the study area were Chaetozone setosa, Aglaophamus malmgreni, Ampharete arctica Terebellides horikoshii, Tharyx sp., and Magelona pacifica. Northern and cold water species were major contributors of polychaete communities in this study area. Dominant species showed their specific depth ranges from shelf area to upper slope and middle slope depth. The overall density was 300 indiv./m$\^$2/ and species richness was around 12 species/0.2m$\^$2/. Significant changes in mean polychaete density and species richness along depth gradient were found approximately at 600 m or deeper depth. Among physical factors, water depth, temperature and clay content, mean grain size were significantly correlated with the mean density of dominant species.

• Journal of Korean Society of Transportation
• /
• v.23 no.3 s.81
• /
• pp.137-147
• /
• 2005

This study is to define new road capacity concept, and to develop and propose an estimation method, through the analysis of individual vehicular behaviors in continuum flow. Developments in detection technology enable various and precise traffic data collection. The U.S. HCM (Highway Capacity Manual) method does not require such various and precise traffic data, and outputs only limited results. Alternative capacity concepts, which can be classified into a stochastic model and behavioral or deterministic model, are attempts for modeling some prominent traffic flow features, namely so-called a capacity drop and a traffic hysteresis, using such various and precise traffic data. Yet, no capacity concept up-to-date can describe both features. The analysis of individual vehicular behaviors, including speed-density plot per time lap, traffic flow-speed-density diagram per each sampling interval, time headway distribution, and free flow speed distribution, is performed for overcoming the limits of the previous capacity concepts. A stochastic methods are applied to determine time headway for estimating freeway capacity for traffic control.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2022.05a
• /
• pp.238-238
• /
• 2022

합천댐의 건설 이후, 댐직하류 구간에서는 10년 동안의 방류량 감소와 기후변화로 인한 강우패턴의 변화로 하도식생의 활착이 발생하여 식생이 증식하고 밀도가 점차 증가하고 있다. 식생밀도의 증가는 흐름에 대한 항력을 증가시켜 유속을 감소시키고 수심을 증가시킨다. 이는 통수능 저하를 초래하며, 홍수 시 수위증가에 따른 홍수범람의 위험성 증가시킨다. 따라서 식생영향에 대한 심화적인 이해를 제고하여 적절한 식생관리대책을 구축할 필요가 있다. 본 연구에서는 이러한 필요성에 맞추어 식생대 영향에 따른 흐름의 변화를 예측모의하여 흐름과 식생대의 상호작용에 대한 분석을 수행하였다. 이를 위해 2차원 흐름모형인 Nays2D를 이용하여 합천댐 직하류 구간을 대상으로 식생밀도의 변화에 따른 흐름의 변화를 부등류를 기반으로 모의하였다. 상류단의 경계조건은 162.99 m³/s(실운영 방류량), 995 m³/s(2년빈도 댐 조절 방류량), 2670 m³/s(100년빈도 댐 조절 방류량)로 3개의 유량으로 구분하여 모의하였다. 식생의 특성은 현장조사를 통해 밀도를 산정하여 수치모의에 적용하였다. 식생밀도는 4가지로 구분하여 모의시나리오를 구축하였으며 현장조사를 통해 산정된 2021년도 식생밀도를 기준으로 식생밀도를 증감하여 수치모의를 수행하였다. 수치모의 조건은 2021년 식생현황, 식생개선, 식생존치, 전벌채로서 식생개선의 경우, 2021년 식생밀도의 0.5배로, 식생존치의 경우, 식생밀도를 2배로 적용하였다. 전벌채는 식생이 없는 것으로 가정하였다. 수치모의 결과, 식생개선이 2021년 식생현황과 식생존치보다 상대적으로 수심이 낮게 나타났다. 식생을 전벌채한 경우, 식생이 존재하는 조건보다 수심이 낮고 유속이 빠르게 나타났으며 특히, 만곡부의 외측에서는 2차류의 발달로 흐름이 집중되었다. 이를 통해 식생개선의 경우, 식생현황과 식생존치보다 홍수범람의 가능성이 적을 것으로 판단되며 전벌채의 경우, 만곡부 외측에서 2차류 발달에 의한 세굴을 야기하여 제방의 안정성에 영향을 줄 것으로 예측된다. 본 연구는 댐 직하류에 식생대 밀도변화가 흐름변화에 미치는 영향을 분석한 수치모의 사례로서 이는 추후 식생을 고려하는 하천관리방안을 수립 시, 식생관리방법에 대한 근거자료로 활용될 수 있을 것으로 기대된다.