• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.5
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• pp.1173-1177
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• 2015

The paper suggests to reclassify the casuality accidents types and causes at urban rail stations in the standardized code manner. In order to make standardized codes, 4,086 casuality accidents for Seoul Metro and Seoul Metropolitan Rapid Transit Cooperation (SMRT) are analysed. The standardized code for casuality accident types includes 4 distinct factors; casuality object, casuality location and casuality pattern. Also, the standardized code for casuality accident causes includes 4 distinct factors: casuality trigger, drinking or not, first cause and second cause. This code is deemed to play a big role to link the same casuality accident types or causes which can be used in the process of railroad safety management and emergency response system.

• Journal of Digital Convergence
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• v.13 no.2
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• pp.35-42
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• 2015

As the value of Bigdata has been recognized importantly, public agencies including the government, private sector, etc. began to have an interest in Big Data. As there are sources of various data, and a variety of planning and analysis methods based on these sources has emerged, It is true that Bigdata will become a tool for creation of the new high qualitied information and decision making based on new insights. The purpose of this study is to find an alternative to the subway congestion problem that is not improved even though the various measures. In this study, we tried to explore approaches for ways to improve the congestion of the Seoul Subway using Seoul Metropolitan public data. Lastly, this study derived a policy alternative to establish new bus route that runs around the metro station that have a high level of congestion.

• Journal of the Korean Society for Railway
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• v.20 no.5
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• pp.637-648
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• 2017

In this paper, the effects of initial built-in deformation and temperature deformation on the stress distribution of discontinuous precast concrete track slab under train load were examined. According to the results, when train load is put on a precast concrete slab with initial built-in deformation and deformation due to temperature gradient, the maximum tensile stresses develop at the upper side of slab in the slab center, edge center and corner of shear pocket; the stress distribution is different from that of the case under train load only. Therefore, to accurately predict the actual weak points and failure modes, one should calculate the stress under train load considering the initial built-in and temperature deformation of the slab.

• Journal of the Korean Society for Railway
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• v.15 no.4
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• pp.402-407
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• 2012

Since reports on trip delays or incidents often appear as accident articles on the press, the social criticisms and concerns on the safety of the urban railway are increasing. Therefore, a railway authority sometimes adopts an abstract safety goal like "let's build the urban railway to a masterpiece level" or "let's obtain an aeronautic safety level" to make citizens relieved and to alert involved persons. However with a vague goal, it is almost impossible to make an implementation plan systematic which helps the authority academically verify and validate if the goal is achieved or not. In this paper, the features of the railway safety are described and the safety models for securing the safety of the urban railway are surveyed and categorized. Based on the comparisons among the features and limitations of the models, we identify a more practical model which can be applied to the urban railway more effectively.

• Journal of Korean Clinical Health Science
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• v.5 no.3
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• pp.907-914
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• 2017

Purpose : This study was conducted to provide basic data on the relationship between environmental factors causing stress in clinical practice institutions and stress levels of dental hygiene students. Methods : The research subjects totaled 207 and it was analyzed with structured questionnaires. The collected data were analyzed using an IBM SPSS ver. 20.0. Results : The environmental factors causing stress according to the status of clinical practice institutions was statistically and significantly different in the case of Busan practice areas (p<0.01), dental university hospitals (p<0.001), attendance times prior to 8am (p<0.001), quitting times that surpassed 8pm (p<0.01), and the number of dentists exceeding 4 (p<0.01). It was found to affect the stress level of students when individuals had to stand for a long period of time(p<0.001, ${\beta}=0.254$) and with the use of unfamiliar tools and equipment(p<0.05, ${\beta}=0.178$). Conclusions : As a result of the research conducted, it should be concluded that dental clinics should provide rest areas for individuals to focus on clinical practice. In addition, it is necessary to develop a systematic program that enables students to communicate with students at any time during the training period.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.4 s.334
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• pp.7-14
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• 2005

Earlier researches have typically concentrated on discovering IP network topology, which implies that the connectivity of all Ethernet devices is ignored. But automatic discovery of Physical topology Plays a crucial role in enhancing the manageability of modem Metro Ethernet mesh networks due to the benefits of Ethernet services, including: Ease of use, Cost Effectiveness and flexibility. Because of proprietary solutions targeting specific product families and related algorithm which depends on Layer 2 forwarding table information it is impossible to discover physical topology in the Ethernet mesh networks. To cope with these shortcomings, in this paper we propose a novel and practical algorithmic solution that can discover accurate physical topology in the Ethernet mesh networks. Our algorithm divides the Ethernet mesh networks into bridged networks and host networks and those bridges located in boundary are named edge bridges. Our algorithm uses the standard spanning tree protocol MIB information for the bridged networks and uses the standard Layer 2 forwarding table MIB information for the host networks. As using the standard MIB information to discover physical topology we can offer interoperability guarantee in the Ethernet mesh networks composed of the various vendors' products.

• The Korean Journal of Applied Statistics
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• v.26 no.4
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• pp.623-634
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• 2013

In this study, we provide empirical evidence of whether a spatial correlation among mode choices at the TAZ(Traffic Analysis Zone) level exists based on transit smart card data observed in Seoul, Korea. The results show that the areas with a higher probability that passengers choose to take a bus are clustered and that those regions have fewer metro stations than bus stations. We also found that the spatial correlation turned out to be statistically meaningful and provided an opportunity for the potential use of the spatial correlation in modeling mode choices. A reliable spatial interaction would constitute valuable information for transportation agencies in terms of their route planning and scheduling based on the transit smart card data.

• Journal of the Korean Society of Safety
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• v.30 no.6
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• pp.139-147
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• 2015

This study deals with actual commuting distance and influence of risk factors depending on commuting distance and mode in order to reestablish actual commuting zone of primary school students. Data mining analysis(CHAID) was applied for this reestablishment using survey results from 6,927 primary school students in Seoul Metro. Six risk factors; convenience level of commuting path condition, convenience level of road crossing condition, vehicle speed on commuting path, segregation level between commuter and vehicle, congestion level of commuting path, and public security level and two mode; walking and cycle are considered in the analysis. As the results of CHAID analysis, commuting distance was divided into four zones; Internal Zone(0.491km under), External Zone(0.492 ~ 1.492km, 1.493 ~ 2.699km), Commutable Zone(2.70km over), and awareness level on safety is declined as commuting distance is increased. The risk factor affecting on safety is recognized differently by students depending on commuting distance and mode. For students commuting by walking, vehicle speed on commuting path and convenience level of commuting path condition are recognized as the prime risk factor within Internal Zone and Commutable Zone, respectively. For students commuting by cycle, convenience level of road crossing condition and vehicle speed on commuting path are recognized as the prime risk factor within Commutable Zone. Analysis results show that improved plan and program for commuting path for primary school students are required considering actual commuting distance and method.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.3
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• pp.529-534
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• 2016

The paper suggests risk management methodology for alleviating casuality accidents at urban railway stations. Risk management deals with countermeasures for reducing accident probability or consequences to reach at the certain level of risk. First of all, Economic evaluations using cost and benefit for all the alternatives are performed. The alternatives exceeding B/C ratio greater than 1, each alternative is applied in the order of higher B/C ratio. this process is repeated when the level of risk is reduced as low as reasonably practical (ALARP). In order to determine the level of ALARP, Level of Service (LOS) for casuality risk at urban railway stations is proposed. The ALARP level is set to the LOS "C". Finally, a case study is applied to the Jongno 3-ga station, which is a highest risky station among all the stations operated by Seoul Metro and Seoul Metropolitan Rapid Transit Cooperation (SMRT).

• Journal of the Korean Society for Railway
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• v.16 no.2
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• pp.144-150
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• 2013

This paper presents an analysis of door design for the Ui LRT based on experiments to predict doorway flow-time and their analyses results. A similar railway vehicle (from Gimhae LRT) and operational conditions are utilized to assess the doorway flow-time through repetitive experiments. Design of the experiments consists of four scenarios, and the experiments are repeated 39 times in total. We use the results of the experiments to verify the design of doors of Ui LRT (e.g. the required number of doors and their width). Various statistical analyses are carried out for the flow-time with respect to the number of boarding/alighting passengers. We make three category levels of boarding/alighting passengers, and analyze the mean and variance for each category, and then carry out One-Way ANOVA to analyze how the number of boarding/alighting and onboard passengers impact flow-time. The results of this paper can be used for making decisions about doors of the LRT vehicle.