• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.6
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• pp.17-29
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• 1999

In this paper, the prioritized queueing handoff scheme in CDMA (Code Division Multiple Access) cellular system is proposed. Also, the analytical survey for the proposed scheme is carried out, and the performance of this scheme is compared with that of non prioritized scheme and FIFO (First In First Out) queue scheme by computer simulation. The handoff region is defined as the time between the handoff treshold and the receiver threshold, and it is used for the maximum queue waiting time in the proposed scheme. The handoff and the receiver thresholds are defined as rewpectively: 1) the time that the Pilot Strength Measurement Message in the neighbor in the neighbor cell is received to the BS (Base Station) under the T_ADD threshold; and 2) the time that the T_DROP timer is expired and the Pilot Strength Measurement Message in the current cell is received to the BS under the T_DROP threshold. The performance metrics for analyzing the proposed scheme are : 1) probability of forced termination; 2) probability of call blocking; 3) ratio of carried traffic to total offered load; 4) average queue size; 5) average handoff delay time in queue. The simulation results show that the proposed scheme maintains high performance for handoff requests at a small penalty in total system capacity.

• Journal of Korean Society of Transportation
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• v.27 no.6
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• pp.79-88
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• 2009

The objective of this study is to develop the new vehicle classification algorithm and minimize classification errors. The existing vehicle classification algorithm collects data from loop and piezo sensors according to the specification("Vehicle classification guide for traffic volume survey" 2006) given by the Ministry of Land, Transport and Maritime Affairs. The new vehicle classification system collects the vehicle length, distance between axles, axle type, wheel-base and tire type to minimize classification error. The main difference of new system is the "Wandering" sensor which is capable of measuring the wheel-base and tire type(single or dual). The wandering sensor obtains the wheel-base and tire type by detecting both left and right tire imprint. Verification tests were completed with the total traffic volume of 762,420 vehicles in a month for the new vehicle classification algorithm. Among them, 47 vehicles(0.006%) were not classified within 12 vehicle types. This results proves very high level of classification accuracy for the new system. Using the new vehicle classification algorithm will improve the accuracy and it can be broadly applicable to the road planning, design, and management. It can also upgrade the level of traffic research for the road and transportation infrastructure.

• Journal of Korean Society of Transportation
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• v.29 no.1
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• pp.39-46
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• 2011

Speeding is a major cause of traffic accidents that affects the safety of pedestrians and harms drivers and their families, property and mental health. However, most researches on speeding behavior have been conducted by survey method, so the relationship between cause and effect is not clear. The reliability of the research cannot be carefully examined because most researches involve retrospective methods. It is clear that conducting experimental research is important for overcoming these limitations, but it is impossible to perform tests with real cars in real traffic situations due to the inability to control situational factors (e.g., other vehicles, traffic signal) which affect participants' behavior. A car simulator experiment was designed and the theory of planned behavior was applied to the experiment. Each participant was grouped and assigned to either high speeding intention group or low speeding intention group according to their levels of speeding intention and analyzed the difference of driving behavior indexes between two groups. The results revealed statistically significant differences between two groups on driving speed, speeding frequency, and accelerator pressure deviation. Finally, the limitations and the implications of this study were discussed.

• The Journal of Sustainable Design and Educational Environment Research
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• v.14 no.2
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• pp.26-36
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• 2015

The new town was assumed that there is a difference between the country's elementary school environment. First, given the important elements of the school safety plan in order to verify this, and we plan to set up each of these elements by safety criteria. In the second chapter in order to achieve the objective of this study was to develop indicators to evaluate the safety of the school environment influences the safety of the school environment through the theoretical consideration. In Chapter 3, the difference in safety through the new elementary school survey of metropolitan areas was given a score per item per item depending on the evaluation criteria. The fourth section is the difference between safety school environment can be summarized as the following analytical results that the difference between the new city. The results of this study as follows: First, the characteristics of the elementary school environment showed a significant difference between the new town. Second, school location, terrain characteristics, bike paths and pedestrian to the installation, the safety of landscape installations, installing median barriers, traffic safety facilities, speed bumps, separation of pedestrian and vehicle circulation in the front door, scores of elements of the plan such as parking scheme there is a difference between the new town. Third, the introduction of elements of the plan such as Traffic calming or Traffic Island installation techniques was found lacking.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.4
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• pp.76-91
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• 2017

The Area of a domestic railway station is designed based on the 4-step traffic demand forecasting model with the average daily passenger count as one of its parameter. However, nowadays, due to increasing rate of railway station's function, the non-passengers are increasing. In order to consider those non-passengers who aren't using trains, assumed volume are added to the average daily passenger count of station to estimate the area, but the criteria being applied has no concrete basis. Therefore, this study aimed to recalculate the increasing non-passenger rate based on actual survey data of station users in any type of railway station to obtain the optimum area. Subsequently, the the design area was performed through pedestrian simulation. According to the result of the simulation, it was found that the total space of the exciting railway stations can be reduced up to 45% and will still satisfy the level of service(LOS) requirement.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.3D
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• pp.403-412
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• 2011

On a curve radius, there is speed deviation because a driver who is on the curve radius can have visual distortion. The curve radius can be more dangerous than a straight radius by many reasons. Especially, visibility paralysis of delineator that is because of night and bad weather. Can pervert the information about curve sections, it threatens safety. More over accident risk is increased by influence to travel speed. Therefore, it needs to build and control delineators for driver's visibility. Therefore, this study focus on finding the two types of delineator(the retro-reflection and inside-lighting delineator) by insight-surveying and the operating speed are compared by survey and operating speed. Finally, inside-lighting delineator will be selected in terms of safety at the curve sections. The inside-lighting delineator was more effective than the retro-reflection delineator on visibility, the necessity of reduction of speed and will reduce the hazard at curve sections. Also, the study analyzes safety is guaranteed by the slight reduction of speed when the driver enters a curve radius with inside-lighting delineator. As a result, the inside-lighting delineator can give the information about horizontal and vertical profile effectively, so it can reduce the accident risk. And it can use to improve traffic safety on curve radius.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.5
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• pp.476-482
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• 2013

This study aims to enhance the effectivity of VTS(Vessel Traffic Service) control by investigating the minimum safe distance between vessel and vessel, vessel and land(obstacle) for the vessel's safe navigation within the VTS control area. In addition, to suggest basic data for the safe navigation, this study has done survey and analysis to each VTS center, and individual on the minimum safe distance to VTS operators of each ports of korea. Through ocean voyage by training ship, Singapore and Malacca strait's congested vessel traffic zone's control distance was compared and investigated the difference on safe distance by the different VTS operators. As a result, there was huge difference of minimum safe distance between the VTS operators belong to the same center. Over all, the port with gentle coastline, like donghae, the safe distance was wider than the other port. On the other hand, port with complex coastline and frequent entry and departure of the vessel, like mokpo, the safe distance was the shortest of all. Therefore, development of module suitable to port's natural conditions and traffic volume's necessity is required, for the operators affiliated to the same VTS center control according to formal method. Lastly, the full discussion by the expert group about establishment of standard control procedure in the future should be considered as well.

• Korean Journal of Construction Engineering and Management
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• v.21 no.5
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• pp.29-37
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• 2020

This study analyzed the importance of factors according to the investor's perspective through a survey of residential real estate experts using AHP and fuzzy theory. Analysis results showed that rent, profitability, traffic accessibility, commercial and infrastructure, and financial regulation are important in common. By expert group, financial and credit groups cited profitability, rent, traffic accessibility, supply and tax benefits, construction and development groups cited traffic accessibility, rent, direct access, profitability, commercial area and infrastructure, and appraisal and evaluation groups cited rent, profitability, transportation accessibility, financial regulation and supply as the most important factors. This showed that it had a preference characteristic that was associated with work. In other words, it focuses most on the financial perspective in investment characteristics, and it values convenience such as accessibility to transportation and commercial districts and infrastructure as its location characteristics. In addition, it was found that easing financial regulations in the market is important to expand investment in real estate. This study aims to help the business feasibility analysis of residential property developers and rational decision-making of general investors who are consumers, taking into account the various perspectives of the expert group.

• Journal of Navigation and Port Research
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• v.42 no.6
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• pp.478-485
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• 2018

Aids to Navigation (AtoN) is one of the marine traffic safety facilities that promotes the safety of maritime traffic and enhance ship's operational efficiency. However, functional failure of AtoN due to ship's collision or bad weather conditions leads to inconvenience or navigational risk to various users such as the ship operators. For insstance, the largest container port in Korea, Busan Port has experienced a total of 400 AtoN accidents in the past 12 years (2006-2017).Therefore, an average of 20.6 days of recovery time is required, which increases the maritime safety anxiety for AtoN users. is the objective of this study was to present the quantitative support of the users for the prevention of AtoN accidents and the improvement of the feasibility of implementing more efficient management in Korea. A survey was conducted on the users of Busan port areas to investigate general perception of AtoN in general and the accidents that have happened, and to estimate the economic value of navigational risk reduction by implementing effective AtoN management measure. Using the representative non-market valuation method for environmental or public goods known as contingent valuation method (CVM), the economic value granted to users for the AtoN services in Busan port was estimated to at least 16 billion won. Therefore, these finding could be used by AtoN managers and/or policy makers as a valuable data to identify the users' need of various AtoN services including Busan Port and to establish and implement more efficient management plan.

• 한국노년학
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• v.37 no.3
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• pp.669-686
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• 2017

The purpose of this study is to investigate types of neighborhood environments and to verify whether the types of neighborhood environments are directly related to life satisfaction of older adults. To achieve this goal, I used'2014 National Survey on Older Koreans' data which surveyed the older adults aged 65 and over living in the community and a total of 10,281 respondents were analyzed. To determine the types of neighborhood environment, the time taken by walking from community organizations or places such as grocery stores, medical centers, administrative agencies, welfare centers, public transportation was used as an neighborhood environment indicators. As a results, there were six types of neighborhood environment: a leisure-welfare walk-limited type(20.3%), a leisure-welfare long-distance type(15.5%), a balanced proximity type(7.8%), a store-traffic type(35.8%), a traffic proximity type(10.1%), and a marginalized area type(11.3%). Compared to the balanced proximity type, older adults living in a store-traffic type and a marginalized area type were more likely to have negative life satisfaction. older adults who have higher life satisfaction were more likely to be female, more educated, get higher household income, and have a spouses or partner. Moreover, the better the health conditions, the higher the frequency of contact with children, siblings, friends and neighbors, the higher the satisfaction of life. Finding from the study highlight the importance of neighborhood environment in late life and provide implications for building age-friendly community.