• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.6
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• pp.1069-1073
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• 2016

The current free-riding subway system for the elderly over 65 years old has been implemented since in 1980. As the aging population increases, the number of free riders also increases. It results eventually in the increase of subsidy from government. In addition, a transfer between subway and bus is not good enough since the free ride system is applied to only subway not to bus. The aim of this study is to analyze the transport card data to understand the impact of free-riding in the viewpoint of economic issues. It aims also to analyze the transfer patterns between public transport. At the end it compares Korea case with international cases and finds out some issues on free-ride systems. Finally, counter-measures aimed at improving the current free-rider system is suggested.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.1
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• pp.83-93
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• 2022

Recently, controversy has been a growing over senior ride-free programs that provide free rides on the subway for those aged 65 or older. In this study, we compare and analyze changes in awareness levels about senior ride-free programs over the past ten years, targeting local government officials in Busan and Gimhae. Busan and Gimhae support an operational deficit of the Busan-Gimhae light rail system, which is the only subway that does not permit senior citizens to ride for free in South Korea. This study traces changes in the level of awareness of local government officials and presents administrative and policy recommendations. We conducted surveys in September of 2011 and April of 2021, finding that the level of awareness clearly differed before and after the opening of the Busan-Gimhae light rail system. We found that positive and negative responses arrived at similar percentages as time passed. Additionally, we found that the percentage of positive statements decreased over time if respondents did not have transportation-related work experience. Also, over time, we found that examining alternatives took priority as opposed to maintaining the current senior ride-free program.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.6
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• pp.1009-1015
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• 2017

Since most of the urban railway operating agencies are established and operated by local governments, Public Service Obligation(PSO) is given priority. Therefore, free riding is carried out based on individual laws and regulations. In Korea, as the aging population goes, the increase in the number of elderly passengers on the urban railways is leading to a free rider as a big part of the fiscal deficit of the city railway operators. However, there have been no previous researches on free pass riding, and especially, it is necessary to study free ride on private investment projects. Several alternatives including a full charge case, free-ride for 70 years old over case, and separate fare charge (900won) are considered. Separate fare charge (900won) was selected as the optimal alternative since there is no fare income adjustment between operating agencies and no subsidy from government.

• Journal of the Korean Society for Railway
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• v.9 no.2 s.33
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• pp.200-205
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• 2006

Subway widely used as a major mean of public transportation both at home and abroad contributes to ease chronic traffic congestion in cities. However, subway operating expense is expected to increase continuously because subway requires vast amount of money at the construction stage, huge sum of maintenance cost is spent during operation, and passenger needs for more convenient facilities is increasing. on the contrary to enormous operating expenses, fare that is occupying most of operating income doesn't come up to its prime cost causing chronic operating deficit. It is urgent to prepare fare system improvement measures to increase operating income in order to resolve financial difficulty of a subway operating organization. Therefore, the current study analyzed present condition and problems of subway fare system, and suggested improvement measures such as improvement of fare adjustment procedure, improvement of free-ride system, diversification of ticket, etc.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.9
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• pp.2285-2301
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• 2012

Peer-to-Peer (P2P) networks are becoming more and more popular in video content delivery services, such as Video on Demand (VoD). Scalability feature of P2P allows a higher number of simultaneous users at a given server load and bandwidth to use stream service. However, the quality of service (QoS) in these networks is difficult to be guaranteed because of the free-riding problem that nodes download the recourses while never uploading recourses, which degrades the performance of P2P VoD networks. In this paper, a distributed trust model is designed to reduce node's free-riding phenomenon in P2P VoD networks. In this model, the P2P network is abstracted to be a super node hierarchical structure to monitor the reputation of nodes. In order to calculate the reputation of nodes, the Hidden Markov Model (HMM) is introduced in this paper. Besides, a distinction algorithm is proposed to distinguish the free-riders and malicious nodes. The free-riders are the nodes which have a low frequency to free-ride. And the malicious nodes have a high frequency to free-ride. The distinction algorithm takes different measures to response to the request of these two kinds of free-riders. The simulation results demonstrate that this proposed trust model can improve QoS effectively in P2P VoD networks.

• The Journal of the Korea Contents Association
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• v.11 no.11
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• pp.120-129
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• 2011

This research aims to investigate the representative affective words and the structure among them to scrutinize user's affect revealed in the ride film based on three dimension stereoscopic image. Previous studies related to the affect were reviewed and the affect words well-suited for three dimension stereoscopic image were collected. Suitability test for two hundred six basic affect words gathered as the result was done from sixty two typical users and four experts. Seventy seven candidate affect words have been selected and by the exclusion of similarity among them, finally twenty six words were extracted from the reduction process. Consequently fifteen representative words and the structure as the network between each word were revealed by using free association test based on twenty six affect words. We propose the affect research including sensors, emotions, and affects related to moving image rather than still mage during doing research affects in most of the previous studies. The future work includes the affect space and the affect effect for ride film based on three dimension stereoscopic image. This study can be adopted practically in the production of ride films and provided with a basic design guideline.

• The Journal of Korean Medicine
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• v.27 no.1 s.65
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• pp.36-46
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• 2006

Objectives : Ginseng Research Group in Korea Food Research Institute developed Saeng Mac San (KFRI-2)and Je Ho Tang (KFRI-3) with their sensory factors more acceptable. And we examined their effects on the short-term recovery capacity for cycling exercise (EX) maintained to all-out. Methods : Seven healthy young subjects (aged $24.0{\pm}2.1yr$) were volunteered at this double blind test. Each of KFRI-2, 3, a commercial sport beverage and control (CON) was offered randomly on a series of EX protocol including 65% VO2max-90min EX (D-ride). 1h-recovery and 85% VO2max EX to all-out (P-ride) under the control of their heart rate (HR) and rating perception of exertion (RPE). Blood samples were collected before D-ride, 30, 60 and 90min in D-ride, 30 and 60min in the recovery period and each 10min in P-ride. Plasma analysis items were glucose, insulin, cortisol (CORT), testosterone (TEST), free fatty acid (FFA), $Na^+$, Cl-and $K^+$. The collected data (Means${\pm}$SE) were analysed by two-way ANOVA and statistically significant differences between treatments (p<0.05) by LSD.; the significant level in FFA, $Na^+$, Cl-and $Na^+$ was p<0.01 Results : At 30min during recovery. plasma glucose level in KFRI-3 was significantly higher than CON, and also insulin in KFRI-3 was than CON and KFRI-2. FFA in KFRI-3 was significantly lower than CON during recovery. $Na^+$ in KFRI-3 significantly higher than CON at 90min in D-ride, and also KFRI-2 was at 60min during recovery. However CORT, TEST, Cl-and $Na^+$ in treated beverages were not significant. KFRI-2, 3 elevated the time for P-ride more than CON did. Conclusions : KFRI-2, 3 elevated the time for P-ride about 12% more than CON did. It is based on rapid recovery of plasma glucose level and inhibition of lipolysis during recovery.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.273-274
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• 2012

This paper investigates control algorithms for a doubly fed induction generator(DFIG) with a back-to-back three-level neutral-point clamped voltage source converter in medium voltage wind power system under unbalanced grid conditions. Two different control algorithms to compensate for unbalanced conditions are proposed. Evaluation factors of control algorithm are fault ride-through(FRT) capability, efficiency, harmonic distortions and torque pulsation. Zero regulated negative sequence stator current control algorithm has the most effective performance concerning FRT capability and efficiency. Ripple-free control algorithm nullifies oscillation component of active power and reactive power. Ripple-free control algorithm shows the least harmonic distortions and torque pulsation. Combination of zero regulated negative sequence stator current and ripple-free control algorithm control algorithm depending on the operating requirements and depth of grid unbalance presents the most optimized performance factors under the generalized unbalanced operating conditions leading to high performance DFIG wind turbine system.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.6
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• pp.550-559
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• 2005

The matrix converter provides sinusoidal input and output wave forms, bidirectional power flow, controllable input power factor and a long life, compared to the VSI(Voltage Source Inverter) with diode rectification stage at the input. However it has tasks, such as complexity of the control method, ride-through problem and low voltage-ratio limitation, to overcome for commercializing, This paper describes the design, construction and implementation of matrix converter based on space vector modulation technique. The implemented prototype of matrix converter is built using the exclusive IGBT module and control circuit constituted with DSP and CPLD and it has an input filter, overvoltage protection circuit and commutation means for overcoming practical issues. The good results tested using an induction motor are also presented.

• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.174-178
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• 2011

This paper deals with the free cooling system of express bus using natural energy source in order to improve the room air quality and save cooling energy. In an express bus, there are may passengers in unit area, requiring the improvement of air quality and giving higher energy saving efficiency. Particularly, the express buses running fast make it easy to take in outdoor air at a flow rate controllable with a damper mechanism. This paper proposes the analysis on the air flow achieved by a damper controlled vertically and horizontally in order not to deteriorate the ride comfort of the passengers.