• Title/Summary/Keyword: Travel-time

Search Result 1,594, Processing Time 0.033 seconds

Density-Based Ramp Metering Method Considering Traffic of Freeway and Ramp on ITS (지능형 교통시스템에서 도시 고속도로와 램프의 교통량을 고려한 밀도 기반 램프 미터링 방법)

  • Jeon, Soobin;Jung, Inbum
    • KIISE Transactions on Computing Practices
    • /
    • v.21 no.3
    • /
    • pp.223-238
    • /
    • 2015
  • Ramp metering is the most effective and direct method to control a vehicle entering the freeway. This paper proposed the new density-based ramp metering method. Existing methods that use the flow data had low reliability data and can have various problems. Also, when the ramp metering was operated by freeway congestion, the additional congestion and over-capacity can occur in the ramp. To solve this problem with the existing method, the proposed method used the density and acceleration data of the freeway and considered the ramp status. The developed strategy was tested on Trunk Highway 62 west bound (TH-62 WB) in Minnesota Twin-City and compared with Stratified Zone Metering(SZM), which had been operating in the Twin-City freeway. To constitute the experiment environment, the VISSIM simulator was used. The Traffic Information and Condition Analysis System (TICAS) was developed to control the PTV VISSIM simulator. The experiment condition was set between 2:00 PM and 7:00 PM, Oct 5th, 2014 during severe traffic congestion. The simulation results showed that total travel time was reduced by 20% for SZM. Thus, we solved the problem of ramp congestion and over-capacity.

Fate and Transport of Viruses in Soil and Groundwater Environments (토양.지하수 환경에서 바이러스의 거동)

  • Park, Jeong-Ahn;Yoon, Seo-Young;Kim, Song-Bae
    • Journal of Korean Society of Environmental Engineers
    • /
    • v.34 no.7
    • /
    • pp.504-515
    • /
    • 2012
  • Groundwater is widely used as drinking water supplies around the world. However, microbial contamination of groundwater is a serious environmental problem that degrades drinking water quality and poses a great threat to human health. Among the pathogenic microorganisms such as viruses, bacteria, and protozoa, viruses are not readily removed during transport through soils, having high mobility in groundwater environment due to their smaller size compared to bacteria and protozoa. Studies regarding the fate and transport of viruses in soils and aquifers are necessary to determine the vulnerability of groundwater to microbial contamination and to secure safe drinking water sources. Also, these studies provide important information to establish the regulations and policies related to public health. This review paper presented the field and laboratory studies conducted for the fate and transport of viruses in subsurface environments. Also, the paper provided the factors affecting the fate and transport of viruses, the characteristics of bacteriophages used for virus studies, and virus transport model/colloid filtration theory. Based on this review work, future researches should be performed actively to set up the viral protection zone for the protection of groundwater from viral contamination sources. Especially, the researches should be focused on the development of mathematical models to calculate the setback distance and travel time for the viral protection zone along with the accumulation of information related to the model parameters.

Seismic Data Processing For Gas Hydrate using Geobit (Geobit을 이용한 가스 하이드레이트 탐사자료 처리)

  • Jang Seong-Hyung;Suh Sang-Yong;Chung Bu-Heung;Ryu Byung-Jae
    • Geophysics and Geophysical Exploration
    • /
    • v.2 no.4
    • /
    • pp.184-190
    • /
    • 1999
  • A study of gas hydrate is a worldwide popular interesting subject as a potential energy source. A seismic survey for gas hydrate have performed over the East sea by the KIGAM since 1997. General indicators of natural submarine gas hydrates in seismic data is commonly inferred from the BSR (Bottom Simulating Reflection) that occurred parallel to the see floor, amplitude decrease at the top of the BSR, amplitude Blanking at the bottom of the BSR, decrease of the interval velocity, and the reflection phase reversal at the BSR. So the seismic data processing for detecting gas hydrates indicators is required the true amplitude recovery processing, a accurate velocity analysis and the AVO (Amplitude Variation with Offset) analysis. In this paper, we had processed the field data to detect the gas hydrate indicators, which had been acquired over the East sea in 1998. Applied processing modules are spherical divergence, band pass filtering, CDP sorting and accurate velocity analysis. The AVO analysis was excluded, since this field data had too short offset to apply the AVO analysis. The accurate velocity analysis was performed by XVA (X-window based Velocity Analysis). This is the method which calculate the velocity spectrum by iterative and interactive. With XVA, we could determine accurate stacking velocity. Geobit 2.9.5 developed by the KIGAM was used for processing data. Processing results say that the BSR occurred parallel to the sea floor were shown at $367\~477m$ depths (two way travel time about 1800 ms) from the sea floor through shot point 1650-1900, the interval velocity decrease around BSR and the reflection phase reversal corresponding to the reflection at the sea floor.

  • PDF

Optimal Rejection of Sea Bottom, Peg-leg and Free-surface Multiples for Multichannel Seismic Data on South-eastern Sea, Korea (동해 남동해역 다중채널 해양탄성파 탐사자료의 해저면, 페그-레그 및 자유해수면 다중반사파 제거 최적화 전산처리)

  • Cheong, Snons;Koo, Nam-Hyung;Kim, Won-Sik;Lee, Ho-Young;Shin, Won-Chul;Park, Keun-Pil;Kim, Jin-Ho
    • Geophysics and Geophysical Exploration
    • /
    • v.12 no.4
    • /
    • pp.289-298
    • /
    • 2009
  • Optimal data processing parameters were designed to attenuate multiples in seismic data acquired in the south-eastern area of the East Sea, in 2008. Bunch of multiples caused by shallow sea water depth were perceived periodically up to two way travel time of 1,750 ms at every 250 ms over seismic traces. We abbreviated sea bottom multiple as SBM, Peg-leg multiple as PLM, and free-surface multiple as FSM. To attenuate these multiples, seismic data processing flow was constructed including NMO, stack, minimum phase predictive deconvolution filter and wave equation multiple rejections (WEMR). Prevalent multiples were suppressed by predictive deconvolution and remaining multiples were attenuated by WEMR. We concluded that combining deconvolution with WEMR was effective to a seismic data of study area. Derived parameter can be applied to the seismic data processing on adjacent survey area.

Study on the Adequacy and Improvement of the Threshold Speed of Expressway Congestion (고속도로 정체 기준 속도의 적정성 검토 및 개선 연구)

  • Lee, Sujin;Ko, Eunjeong;Jang, Kitae;Park, Sungho;Park, Jaebeom;Yun, Ilsoo
    • The Journal of The Korea Institute of Intelligent Transport Systems
    • /
    • v.19 no.5
    • /
    • pp.40-51
    • /
    • 2020
  • Much time has passed since Korea's expressway congestion-threshold speed was revised in 2011. In the meantime, various expressway environments have changed owing to improved performance of vehicles, expanded operations of transport competition (i.e., the KTX), and increased speed limits along some expressway sections. In addition, the speed that expressway users expect to travel at is also increasing. Therefore, through a survey, this study investigates expressway users' perceptions of congestion, and reviews the adjustment of the expressway speed congestion threshold by analyzing expressway traffic flow. One result of the survey confirms that the threshold speed expressway users consider to be congestion has slightly increased. Analyzing traffic and speed data through a K-means algorithm found that the threshold speed for congestion is 60 km/h. In addition, assuming the congestion threshold speed increase from 40 km/h to 50 km/h and 60 km/h, frequently congested expressway sections are identified, determining that 50 km/h is appropriate as a congestion threshold for proper expressway mobility management.

Letters by Medical Missionaries to Korea: Exploring Digital Humanities Approaches (북미지역에 소장된 내한 의료선교사 편지 기록의 현황과 디지털 인문학적 활용 가능성)

  • Hur, Kyungjin;Kim Han, Mikyung;Lee, Hye Eun
    • Journal of the Korean BIBLIA Society for library and Information Science
    • /
    • v.29 no.1
    • /
    • pp.233-252
    • /
    • 2018
  • The first Protestant medical missionary, Horace Allen, came to Korea in 1884 and built the first western-style hospital, Jaejungwon. John Heron, Oliver Avison and other foreign medical doctors soon followed. They established hospitals and medical schools, and, by treating patients and educating native doctors, they disseminated and developed modern medicine in Korea. At the same time, they wrote letters and reports to their sponsoring agencies, as well as family and friends, thereby leaving a vast body of literature that is scattered all over the world. Since the end of the 19th century, the records left by foreign medical missionaries have been valuable resources for the study of Korean history. While all types of records, such as diaries, memoirs, reports and travel logs, are available, these tend to be exaggerated or unverifiable because they are unilateral records. In contrast, letters can be verified because they are bilateral records between the recipient and the sender, and cannot be modified or altered according to changes in circumstances. Despite the academic value of these materials, however, there have been insufficient efforts to discover or identify these primary data sources, or to systematically organize them for scholars. This paper identified 49 archival collections from 29 institutions in North America. After analyzing their academic value, the paper will explore digital humanities options in utilizing the letters for future scholarship.

Dynamic Characteristics of Railway Structures under High-Speed Train Loading (고속열차 주행 시 동적하중을 받는 철도구조물의 진동 특성)

  • Rhee, Inkyu;Kim, Jae Min
    • Journal of the Computational Structural Engineering Institute of Korea
    • /
    • v.33 no.2
    • /
    • pp.121-128
    • /
    • 2020
  • The purpose of this study is to investigate the distribution patterns of displacement and acceleration fields in a nonlinear soil ground based on the interaction of high-speed train, wheel, rail, and ground. For this purpose, a high-speed train in motion was modeled as the actual wheel, and the vertical contact of wheel and rail and the lateral contact, caused by meandering motion, were simulated; this simulation was based on the moving mass analysis. The soil ground part was given the nonlinear behavior of the upper ground part by using the modified the Drucker-Prager model, and the changes in displacement and acceleration were compared with the behavior of the elastic and inelastic grounds. Using this analysis, the displacement and acceleration ranges close to the actual ground behavior were addressed. Additionally, the von-Mises stress and equivalent plastic strain at the ground were examined. Further, the equivalent plastic and total volumetric strains at each failure surface were examined. The variation in stresses, such as vertical stress, transverse pressure, and longitudinal restraint pressure of wheel-rail contact, with the time history was investigated using moving mass. In the case of nonlinear ground model, the displacement difference obtained based on the train travel is not large when compared to that of the elastic ground model, while the acceleration is caused to generate a large decrease.

Crustal Structure of the Korean Peninsula by Inverting the Rravel Times of First-arrivals from Large Explosions (대규모 발파자료 초동주시 역산을 통한 한반도 지각 속도구조 연구)

  • Kim, Ki-Young;Hong, Myong-Ho;Lee, Jung-Mo;Moon, Woo-Il;Baag, Chang-Eob;Jung, Hee-Ok
    • Journal of the Korean Geophysical Society
    • /
    • v.8 no.1
    • /
    • pp.45-48
    • /
    • 2005
  • In order to investigate the velocity structure of the southern part of the Korean peninsula, exploded seismic signals were recorded for 120 s along a 294-km WNW-ESE line and 150 s along a 335-km NNW-SSE line in 2002 and 2004, respectively. Velocity tomograms were derived from inverting first arrival times. One-dimensional velocity models derived by joint analyses of teleseismic receiver functions and surface wave dispersion at several stations near the profiles were uesd to build initial models. The raypaths indicate several midcrust interfaces including ones at approximate depths of 2.0 and 14.9 km with refraction velocities of approximately 6.0 and 7.1 km/s, respectively. The deepest significant interface varies in depth from 30.8 km to 36.1 km. The critically refracting velocity varies from 7.8 to 8.1 km/s along this interface which may correspond to the Moho discontinuity. The velocity tomograms show (1) existence of a low-velocity zone centered at 6-7 km depth under the Okchon fold belt, (2) extension of the Yeongdon fault down to greater than 10 km, and (3) existence of high-velocity materials under the Gyeongsan basin whose thickness is less than 4.2 km.

  • PDF

Transplantation of Koelreuteria paniculata by Sea Current (모감주나무의 해류에 의한 전파)

  • 이영노
    • Journal of Plant Biology
    • /
    • v.1 no.1
    • /
    • pp.11-20
    • /
    • 1958
  • I. Assumption: Mo-kam-ju, Koelreuteria paniculata is a woody plant mainly cistributed over Northern China. Its sporadic growth along the beaches of Korea and Japan is assumed to have been sowed by the seeds transported adrift on the current across the ocean. II. Use and Growth of the Plant: In China, this plant has been cultivated from early times mainly at temples, it seeds being used as rosaries, its flowers for yellow dyes and medicine for the eyes, and its leaves for black dyes. In Korea and Japan, these plants have been cultivated at temples and used as the material for rosaries. No natural growth of these plants was reported until 1919. III. Discoveries: In this domestic area, Dr. Chung Tae Hyun discovered the plant on the beach between Cho-Do and Chang-san-kot, Hwang-Hae Prov. in 1920. The reporter discovered them on the beach at Buk-Ni, Duk-jok-Do in 1948, at An-Hung in 1956 and on the beach at An-min-Do in 1957. In the Japan area, it was discovered for the first time twenty years ago, mainly along the coast line of the Japan Sea and some along the eastern coast line, at Subo, Yamaguchi Prefecture facing the Pacific Ocean. IV. Study and Experiment: A. Seed The seed coat is thick, non-permeable and floatable. A number of seeds were immersed in artificial sea water and fresh water separately. The seeds remained there for a hundred and forty-five (145) days from April 6, 1957 to August 29, 57. Thirty one seeds out of the fifty immersed in salt water and twenty seeds out of the fifty immersed in fresh water remained on the surface of the water, proving them to be non-permeable to both sea and fresh water. Of course, these had retained their germinating capabilities. Five (5) seeds out of twenty from the fresh water and six (6) out of thirty-one from the sea water were successfully germinated after a hole had been drilled in the seed coat and they had been planted. Thus their floating capability, non-permeability and germinating capability after a possible 145 day trip on the flowing currents has been proved satisfactory according to the assumption made above. B. Current As shown in the Data 2 and 3, the sea current initiated in the Pohai Sea flows westward down along the coast line of Korea reaching the southern part during the autumn and winter seasons. This fact also is in favor of the reporter's assumption. V. Discussion and Conclusion: The reporter concludes that, as discussed above, Koelreuteria paniculata which originates in Northern China is transported adrift on the flowing sea current to our western coast line, and also the coast lines of Shantung and Kuangtung of China and it is germinated on the sandy beaches forming new plants. Thus, the seeds drifted down on the southern beach of Korea and have been transported to the Japanese coast, adrift on the Tae-Ma current. Upon fruition, the seeds of the plants which settle on the coasts of western Korea and Japan will migrate to new places. It can be, however, assumed that while the thickness and nonpermeability of the coat enables the long travel in the water, this also can compose a difficulty in germination, consequently in developing a new distribution of this species.

  • PDF

Prediction of a Debris Flow Flooding Caused by Probable Maximum Precipitation (가능 최대강수량에 의한 토석류 범람 예측)

  • Kim, Yeon-Joong;Yoon, Jung-Sung;Kohji, Tanaka;Hur, Dong-Soo
    • Journal of Korea Water Resources Association
    • /
    • v.48 no.2
    • /
    • pp.115-126
    • /
    • 2015
  • In recent years, debris flow disaster has occurred in multiple locations between high and low mountainous areas simultaneously with a flooding disaster in urban areas caused by heavy and torrential rainfall due to the changing global climate and environment. As a result, these disasters frequently lead to large-scale destruction of infrastructures or individual properties and cause psychological harm or human death. In order to mitigate these disasters more effectively, it is necessary to investigate what causes the damage with an integrated model of both disasters at once. The objectives of this study are to analyze the mechanism of debris flow for real basin, to determine the PMP and run-off discharge due to the DAD analysis, and to estimate the influence range of debris flow for fan area according to the scenario. To analyse the characteristics of debris flow at the real basin, the parameters such as the deposition pattern, deposit thickness, approaching velocity, occurrence of sediment volume and travel length are estimated from DAD analysis. As a results, the peak time precipitation is estimated by 135 mm/hr as torrential rainfall and maximum total amount of rainfall is estimated by 544 mm as typhoon related rainfall.