• Journal of the Korean Institute of Gas
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• v.13 no.2
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• pp.49-56
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• 2009

This thesis suggests ways for ensuring the safety of domestic autogas (liquefied petroleum gas) vehicles by conducting comparison and analysis on the status of market diffusion and safety management scheme in foreign countries as well as in Korea. According to the result of the survey on the status of domestic autogas safety management, the national scheme to secure the safety of autogas vehicles seems neither well-organized nor sufficiently-controlled. Actually, the gas leakage check-ups conducted for 5,000 autogas cars revealed that about 4 percent of them had leakage problems. As a result, it was acknowledged that the autogas safety regulations being operated in advanced countries need to be selectively introduced for the domestic autogas industry. Consequently, in line with the recent permission to use autogas as a fuel for subcompact cars etc., this thesis is recommending some methods to enhance the safety management scheme for autogas cars such as the amendment of facility regulations including the ventilation of underground parking lots, mandatory attachment of labels claiming autogas cars and indicating periodical inspections etc.

• Journal of Labour Economics
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• v.27 no.1
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• pp.77-105
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• 2004

Given the limitations of UI benefit and self-insurance through precautionary savings, this paper suggests a new scheme of income support for the unemployed, which offers unemployed workers not only UI benefit but also borrowings from their future pension incomes. Allowing individuals to have effective self-insurance through pension- borrowing, this scheme provides them with consumption-smoothing and reduction in risk burden while maintaining search incentives of the unemployed. Simulation study based upon household panel data in Korea suggests that a heavy reliance should be set upon self-insurance through pension-borrowings rather than upon UI benefit, even for the low-income individuals who are subsidized under UI system. This result provides us with insightful implications for a social safety net in (fast-growing) developing countries, where people cannot afford a good amount of UI benefit or of precautionary savings against unemployment although they expect their incomes to be much higher in the future. Indeed, it is consumption-smoothing effect of self-insurance through pension- borrowings, as well as its incentive-maintaining effect, that makes it a promising alternative of social safety net in developing countries.

• Journal of the Korean Society for Railway
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• v.12 no.6
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• pp.983-988
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• 2009

When the railway vehicle passing through curves & transitions, the running speed must improve by proposing the practical standard about maximum running possibility speed of each section on existing line considering running safety. In this paper, when the railway vehicle passing through curves of actual track conditions (Namsunghyun-Chungdo up & down lines), the effect that has influence on running safety is examined to devise the high speed of vehicle which passing through curves which risk of derailment is high. The running safety analysis is performed that running speed by curve radius improves 5-20% compared with existing speed under actual track conditions. In result of the running safety analysis, in case the speed condition is fewer than 15% compared with existing speed, the derailment coefficient and unloading ratio are within acceptable level. so we could confirm possibility of speed improvement on the whole Namsunghyun-Chungdo up & down lines.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.3
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• pp.245-252
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• 2016

The development of Top-Mounted In-Core Instrumentation(TM-ICI) is an ongoing project to reduce the risk due to severe accidents by inserting the instrumentation into a reactor closure head instead of a reactor bottom head. As part of this project, environmental fatigue analyses for TM-ICI nozzle have been performed using two methods of NUREG/CR-6909 and Code Case N-761. TM-ICI nozzle is subjected to transient loads for level A, level B and test conditions that should be evaluated for a fatigue analysis. It is found that a cumulative usage factor considering reactor coolant environment for TM-ICI nozzle is evaluated as less than 1, which is ASME Code allowable criteria of a fatigue analysis.

• Journal of the Korea Concrete Institute
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• v.14 no.6
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• pp.961-972
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• 2002

Flat plate structures under lateral load are susceptible to the brittle shear failure of plate-column connection. To prevent such brittle failure, strength and ductility of the connection should be ensured. However, according to previous studies, current design methods do not accurately estimate the strength of plate-column connection. In the present study, parametric study using nonlinear finite element analysis was performed for interior connections. Based on the numerical results, a design method for the connection was developed. At the critical sections around the connection coexist flexural moment and shear developed by lateral and gravity loads, and maximum allowable eccentric shear stresses were proposed based on the interactions between the flexural moment and shear, The proposed method can precisely predict the strength of the connection, compared with the current design provisions. The predictability of the proposed method was verified by the comparisons with existing experiments and nonlinear numerical analyses.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.4
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• pp.68-80
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• 2016

This study proposes the traffic prediction and optimal traffic control system based on cell transmission model and genetic algorithm in cloud environment. The proposed prediction and control system consists of four parts. 1) Data preprocessing module detects and imputes the corrupted data and missing data points. 2) Data-driven traffic prediction module predicts the future traffic state using Multi-level K-Nearest Neighbor (MK-NN) Algorithm with stored historical data in SQL database. 3) Online traffic simulation module simulates the future traffic state in various situations including accident, road work, and extreme weather condition with predicted traffic data by MK-NN. 4) Optimal road control module produces the control strategy for large road network with cell transmission model and genetic algorithm. The results show that proposed system can effectively reduce the Vehicle Hours Traveled upto 60%.

• Journal of Navigation and Port Research
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• v.38 no.3
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• pp.253-259
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• 2014

Traffic risks in fairway and harbour area increase lately according to be a sharpe change of ship's size and speed. It becomes hot issue to design a fairway, which's width is important to lower traffic risk and ensure navigational safety. The current design making a fairway and width do not focus on maneuvering motion of a large ship, but traffic risks are clear on reflecting the design of fairway, specially on width. To contact with these problems, this research proposes how to determine fairway' width in consideration of traffic volume. it suggests several situations of marine traffic congestion as like narrow channel and harbour area. here uses 162 simulations in MTS Ver.1 developed. Acquired simulation's results, environmental stress dates, figure in a model that relates with required fairway' width and allowable traffic volume. In added, suggested model compares current design with an width.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.1C
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• pp.90-95
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• 2002

Though the FTP(File Transfer Protocol) has been used widely and stable, It has the structural weakness that can't support current file transmissions so that we have to wait the completion of previous file transmission when try to transmit another file. If try to transmit multiple files concurrently using this FTP, It has to forking multiple FTP servers and clients in each user's PC and ISP's host machine it would result in the waist of memory, resource of network and the high workload of system. In order to solving previous problem, in this paper I have designed the new model of FTP which based on multi-thread and created NFTP(Next-Generation FTP)protocol so that may reduce the workload of system and support current file transmission effectively. I have implemented NFTP and also applied to real service, as a result It have provided reliable service by reducing the workload of system and saved the waiting time which would happened.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.3
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• pp.549-555
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• 2007

A digital signature scheme provides integrity of the document, authentication and non-repudiation of a signer. Usually the key for digital signature is stored in hard disk or removal disk storage. The drawback of this approach is that the signer can let the agent to sign instead of the signer by providing the key information. It can be abused in applications such as electronic election. In this paper, we propose the undeniable biometric digital multi-signature scheme suitable for applications where the signer should not make an agent sign instead of himself/herself. The undeniable multi-signature scheme requires many signers and only the designated user can confirm the authenticity of multi-signature. The proposed scheme satisfies undeniable property and it is secure against active attacks such as modification and denial of the multi-signature by signers. As the key is generated through the signer's fingerprint image, it's also secure against signing by an agent.

• Korean Journal of Food Science and Technology
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• v.27 no.6
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• pp.871-877
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• 1995

Dietary intake and oncogenic risk of 12 pesticides used in Korea whose oncogenic potency was known were assessed from published data. Dietary oncogenic risk (excess tumor incidence for a 70-year human life span) for Korean population was estimated to be $2.17{\times}10^{-3}$ on the basis of legal maximum residue limit, $4.33{\times}10^5$ on the basis of maximum practical residue level and $5.10{\times}10^{-6}$ on the basis of mean practical residue level of examined pesticides, all of which exceeded the negligible risk standard $1{\times}10^{-6}$ of US EPA. A systematic follow-up study on those oncogenic pesticides should be undertaken in order to mitigate the people's worry about the cancer risk by the abuse of pesticides in food production.