• IEMEK Journal of Embedded Systems and Applications
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• v.13 no.2
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• pp.65-71
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• 2018

In order to make the underwater vehicle carry out the mission in a submarine environment, it is needed to plan a safe and efficient route to a given destination and prevent the autonomous submersible from colliding with obstacles while moving along the planned route. The function of collision avoidance makes the travel distance of the autonomous submersible longer. Moreover, it should move slowly near to obstacles against their moving disturbance. As a result, this invokes the degradation of the navigation efficiency in the process of collision avoidance. The side effect of the collision avoidance is not ignorable in the case of high congested environments such as the coast with many obstacles. In this paper, we suggest a path planning method which provides the route with minimum travel time considering collision avoidance in congested environment. For the purpose, we define environmental congestion map related to geometric information and obstacles. And we propose a method to consider the moving cost in the RRT scheme that provides the existing minimum distance path. We verified that the efficiency of our algorithm with simulation experiments.

• International Journal of Highway Engineering
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• v.13 no.3
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• pp.147-156
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• 2011

Since the urbanization process has been taking place, negative outcomes such as environmental pollution and traffic congestion have produced as well. Reflecting the phenomenon, our study assumed that physical structure of urban form were implicit in relation to both economic performance and cost. It can be interpreted that as the urban space has been growing bigger, economic performances such as regional product output, economy of scale and the effect of agglomeration economies are increased. On the contrary, the negative effects such as environmental pollution and traffic congestion were incurred as economic loss and expenses. It means that even though economic performance can help increase regional product output, we should consider the loss on economic expenses which are paid for social problems such as environmental pollution and traffic congestion, which are caused by urbanization. Therefore, this study aims to statistically validate the relationship between traffic congestion as the most representative economy costs and physical characteristics of urban in a large city such as Seoul and to suggest its implications. As a result of model development for empirical analysis, GRDP(0.604), the population(0.582), employment GINI coefficients(0.296), population GINI coefficients(0.254) in order led to congestion cost. We can come to the conclusion that in case of scale factor such as the population, if the population tends to concentrate, urban becomes more crowded and that if GINI coefficients (the population, employment) which are variable on inequality according to region have the disparity with surrounding areas, congestion cost is caused a lot on account of movement related with employment. In addition, this phenomenon was caused if both the population and employment were geographically biased on one side.

• Journal of Environmental Health Sciences
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• v.46 no.2
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• pp.204-213
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• 2020

Objective: This study is aimed at investigating indoor air quality on public transportation (subway, train, and bus) according to changes in season and time. Methods: We evaluated TVOC and HCHO on public transportation based on the un-controlled parameters of the Ministry of Environment. We also measured temperature and humidity since they affect the concentration of TVOC and HCHO. For public transportation classification, subway lines were classified into Lines 1 to 4. Additionally, trains were classified as ITX and KTX. Results: When comparing summer and winter on public transportation, the concentrations of TVOC and HCHO did not show any particular tendency. However, the concentrations of TVOC and HCHO during traffic congestion was higher than levels during times of non-congestion on most public transportation. In summer and winter, the measurement results for temperature and humidity showed a normal range, so temperature and humidity did not affect the concentrations of TVOC and HCHO. In the case of TVOC, TVOC concentrations on new trains were found to be relatively higher than on older ones, but there was no statistically correlation. Conclusions: A survey was conducted on the indoor air quality on public transportation. This study also analyzed data based on TVOC and HCHO for designing policies and managing indoor air quality.

• Journal of Korean Society of Transportation
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• v.19 no.6
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• pp.49-63
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• 2001

The pattern of urban transport activity has two major components: the movement of people and the movement of goods. Roads in urban areas carry large number of trucks laden with goods that support urban economy and lifestyle. Therefore urban goods movement plays a vital role, but at the same time, urban goods movement are an important source of congestion, and a major contributor to the adverse environmental and social impacts of urban transport. In addition, the demand for goods movement is growing at a faster rate than personal travel in many cities, due to changes in industry logistics and consumer purchasing patterns. As a result, the significance of urban freight activity is increasing in terms of both its role in urban economy and its adverse impacts on urban amenity. This study is focused on the role and involvement scope of metropolitan government in urban logistics aimed at increasing its efficiency and reducing its negative impacts. The major suggestions of this study are (a) development of a measure of urban goods movement activity, (b) evaluation of data requirements and availability, (c) dialogue between the public sector and private sector, and (d) the role of metropolitan government.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.3D
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• pp.189-196
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• 2012

South Korea has achieved economic development rapidly during last 50 years. However, such fast economic development with industrialization caused skyrocketing increase of automobiles. The increase of automobile has created various problems in the cities. Problems like traffic congestion and accident, environmental pollution, noise, and vibration have done human beings, who are the principal agents harm. They have made citizens understand how important Green transportation, especially pedestrian movement, is. Recently, installation of pedestrian facilities has been expanded. If walking facilities are incorrectly designed, they can create inconvenience, danger and the state of emergency due to the lack of safety and pleasant feelings. However, since the importance of the facility designs has been neglected due to the lack of understanding, it is hard to improve the facilities. Therefore, we need various studies of walking simulation in order to research the designs for pedestrians' safety and convenience. The objective of this study is to analyze the pedestrians' behavior and movement in a transfer subway station. The improvement of walking environment was made after chasing and analyzing the pedestrians' movement which is investigated in the actual field using SimWalk simulation program.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1998.10b
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• pp.11-25
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• 1998

Many Countries have made efforts to assist ships navigate accurately , safely and expeditiously for the safety control against increasing marine traffic , in their coastal waters. However, they are exposed in spite of these efforts,to risks of casulaties and marine polluation caused by traffic congestion when ships are navigating through waterways approaches to ports or harbors and in narrow fairways. Therefore, efficient control of VTS in Port is necessary nowadays to provide ships with necessary service , which interacts with shipping and organize the flow of traffic so as to maximize the efficiency of the port or harbor while minimizing the risk of accident and environmental pollution. Even though the navigation condition of ships is very inferior compared to other ports in Korea, such as the big difference between the ebb and flood tide, the frequent fog, the narrow fairway , the density of navigation traffic in Inchon Port is high and transportation quantity of dangerous cargoe increases gradually. In cosideration of the characteristics of natural circumstance and traffic circumstance the VTS established newly in Inchon port have to operate efficiently. The purpose of this study is to help efficient operation of VTS in Inchon port by accomplishing both the literature research and questionnaire survey. Questionnaire survey was read to the VTS personnel in Inchon Port and customer familiar to Inchon Port such as ship navigators, pilots, shipping companies and so on. Most of ship navigators who occupy half of the respondents are Korean Officer who had responded while they were calling at Inchon port. The conclusions and recommendations includes ; First, the service area should be extended over Designated area to provide the vessel with navigational assistance service regarding the information of traffic congestion area, fishing boat and small ship's activities. Second, the types of information service to be offered are ship's movement and weather condition inthe vicinity of the port and state of fairway in the approaching channel to thte fairway. Third, VTS personnel should be upgraded by the on-the-job training and continuous simulation training as well as supplement of the qualified personnel for VTS operation. Fourth , the Harbor Master System to be introduced for safe navigation and efficient port operation.

• Journal of fish pathology
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• v.18 no.1
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• pp.29-37
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• 2005

This study investigated external symptoms, behavior characteristics and the distribution pattern of the scuticociliates in the skin, gill and blood vessel of the tiger puffer, Takifugu rubripes, infected with scuticociliates among tiger puffer cultured. The fish infected with scuticociliates did not show any external symptoms, such as change in body color or swimming behavior, in the early infection stage. However, they showed congestion, erosion, and ulcer on the skin and fin at advanced stages. They showed a turning movement, mainly stayed on the bottom, and swam with their mouths open at the surface of water. Some fish showed a sudden swimming movement of zigzag type. The scuticociliates were ovoid in shape and $20\times40{\mu}m$ in size. The scuticociliates had a contractile vesicle and a caudal cilium that ranged 10-12 ${\mu}m$, and reproduced by binary fission. Therefore the scuticociliates were identified as ciliated, belonging to class Hymenostomatia, order Scuticociliatida in morphogenetic character. The gills infiltrated with scuticociliates showed clubbed gill filament due to hypertrophy of gill lamella. Within the blood vessels, scuticociliates were observed one to ten individuals, depending on diameter of the blood vessels. Some of the scuticociliates were observed to have ingested erythrocytes.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.2 no.2
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• pp.1-10
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• 1982

Presently, most of rail stations are situated on the surface of dowl1town and thus result in heavy traffic congestion and inefficient use of land. This paper analyzes the impact of alternative locations of station On urban traffic patterns by simulating transportation systems, of Busan city. Since location of station has long-term effects on land use and transportation, 20 years forecast of land use change, trip generation, trip distribution, modal split and network assignment was performed for each alternative, and aggregate Impacts On passenger-km and passenger-hour were computed. The result indicated that Bujeon is the most desirable location of station in terms of traffic movement, compared to the alternative locations of Sasang and existing station. Relocation of rail station, however, should be decided with broader analysis including other aspects, such as urban development, environment, construction and operating costs, etc.

• Journal of Korean Society of Transportation
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• v.24 no.1 s.87
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• pp.7-18
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• 2006

Nowadays, the movement of commercial vehicles has caused severe congestion, environmental problems and damaged pavements in urban area. To solve the Problems, this research has proposed a methodology to build-up a freight network that is enable to manage the movement and demand of commercial vehicles. The network based on urban arterial network has developed according to freight traffic volume that is under the influence of road types among The in study area. Freight network has been developed by assignment method of 4-step transportation forecasting. Once, acceptable limits of freight traffic volume are decided, freight network can be developed using the capacity To confirm the application of the methodology, freight network of Seoul city has developed by the methodology.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.1
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• pp.101-108
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• 2024

The total number of railroad stations managed in Korea is 322 (including general and wide-area railways), and a considerable number of stations are aging. In terms of the size of the existing railway station and the number of entrances, it has not been possible to secure adequate service capacity, and the demand for station improvement is increasing due to changes in surrounding conditions such as urban development. In the past, railroad stations were focused on the simple function of a connection passage in terms of maintenance or management, but in recent years, railroad stations are also changing to an atmosphere that they should be reborn as a user-centered comfortable, convenient, and safe service provision space. In this study, a case study related to the improvement of the old railway station was conducted to derive an improvement plan that meets the improvement standard of the old station, and the service level evaluation standard was developed. By introducing the concept of service level (LOS) in the development model, station congestion, station movement convenience, and station safety were selected as evaluation indicators. In addition, this development model applied an analytical stratification technique to divide various evaluation elements of each indicator into major and detailed elements and derive the relative importance of the elements by class. Priority for improvement was derived using the ratio of the number of E and F on the LOS for each facility. Based on this study, it is expected to be helpful in using it as an evaluation criterion for improving objective and equitable railway station.