• The Journal of the Convergence on Culture Technology
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• v.6 no.3
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• pp.393-399
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• 2020

In this study, the subsidence behavior caused by groundwater ex-flow in a limestone cavity encountered during tunnel excavation was quantified based on numerical analysis and the effect was analyzed. Based on the groundwater level and surface subsidence surveyed at the site, a numerical analysis technique was applied to analyze the characteristics of the subsidence behavior according to the tunnel passage of the geological vulnerabilities. The results of groundwater seepage-coupled analysis were analyzed to reflect the actual ground subsidence behavior. As a result of the study, it was analyzed that the ground subsidence due to the tunnel excavation in the limestone common section(the geological vulnerable zone) was analyzed that the dramatical decrease in groundwater level was the main cause. As a result of numerical analysis, it was analyzed that the long-term cumulative settlement of the asphalt surface after the groundwater ex-flow was 76~118mm due to the reduction of the volume of the soil layer due to the decrease in the groundwater level, and the settlement amount increased as the depth of the soil layer increased.

• Journal of the Korea Society of Computer and Information
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• v.16 no.2
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• pp.173-181
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• 2011

User authentication and key exchange protocols are the most important cryptographic applications. For user authentication, most protocols are based on the users' secret passwords. However, protocols based on the users' secret passwords are vulnerable to the password guessing attack. In 1992, Bellovin and Merritt proposed an EKE(Encrypted Key Exchange) protocol for user authentication and key exchage that is secure against password guessing attack. After that, many enhanced and secure EKE protocols are proposed so far. In 2006, Lo pointed out that Yeh et al.'s password-based authenticated key exchange protocol has a security weakness and proposed an improved protocol. However, Cao and Lin showed that his protocol is also vulnerable to off-line password guessing attack. In this paper, we show his protocol is vulnerable to on-line password guessing attack using new attack method, and propose an improvement of password authenticated key exchange protocol for imbalanced wireless networks secure against password guessing attack.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.5
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• pp.581-591
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• 2016

RFID(Radio Frequency IDentification) is a key technology in ubiquitous computing and is expected to be employed in more fields in the near future. Nevertheless, the RFID system is vulnerable to attacks by eavesdropping or altering of the messages transmitted in wireless channels. In 2013, Oh et al. proposed a mutual authentication protocol between a tag and a reader in RFID systems. Their protocol is designed to resist location tracking for privacy protection. However, all tags and readers use only one network-wide key in their protocol and tags are usually vulnerable to physical attacks. We found that their protocol is still vulnerable to tag/reader impersonation attacks and location tracking if an attacker obtains the network-wide key from a tag. In this paper, we propose a security improved authentication protocol for privacy protection in RFID systems. In addition, we demonstrate that the proposed scheme is efficient in terms of computation and communication costs.

• Journal of Korean Society for Geospatial Information Science
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• v.21 no.3
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• pp.27-35
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• 2013

This study intends to analyze the accessibility to the evacuation shelters according to pedestrian characteristics for Shinpo-district and Haewoon district, Masan Happo-gu, Changwon, designated as Disaster Risk Districts(Typhoon and Storm Surge Risk Zones) due to the typhoon and surge disasters of the past such as Typhoon RUSA or MAEMI. Evacuation speed was analyzed by dividing the types of evacuees into children, general adults, and the aged people by considering physical conditions. In the case of Haewoon district, currently designated evacuation shelters appeared to be appropriate. But in the case of Sinpo district, over 50% of designated Disaster Risk Districts appeared to be evacuation-vulnerable zones in the case of the aged. Therefore, three additional shelters were designated to complement these problems. The results reveal that the problems about the evacuation-vulnerable zones in the case of the existing designated shelters, appeared to be improved. It is expected that the results, obtained in this study will be utilized to establish the complementary measures to analyze the evacuation risk and solve the problems.

• The Journal of the Korea Contents Association
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• v.12 no.7
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• pp.295-305
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• 2012

This study analyzes actual conditions of private health insurance empirically by using the decision to join Korea Health Panel data. First, the study investigates how sociodemographic factors influence joining the private health insurance. Next, the relationship between the private health insurance membership and the frequency of medical service utilization is analyzed. The main results of these analyses can be summarized as follows: the socially vulnerable are less likely to join private health insurance relative to the middle and upper classes. The frequency of medical service utilization of private insurance members is relatively higher. This fact contains the possibility that the middle and upper classes are able to receive more medical services through private health insurance membership, while the socially vulnerable have difficulty with obtaining medical services in spite of much need. Therefore, policies are needed which manage the private health insurance more effectively and secure the publicity of health service socially.

• KIEAE Journal
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• v.16 no.2
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• pp.53-66
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• 2016

Purpose: This study aimed to find out the characteristics of the communal shared housing preferred by the housing vulnerable single-person household young adults and adults. It also intended to identify overall characteristics of the young adults and adults and compare and analyze the differences. Method: The the questionnaire using face-to-face interview was conducted. The research subjects were 100 housing vulnerable single-person household young adults and adults, who were living in Gosiwon, Jjokbang, detached houses below the minimum housing standards, multiplex housing units and multi-household houses in Seoul. The research was conducted on the general characteristics, housing environmental characteristics, preferred characteristics of space planning and non-physical elements on the communal shared housing, and the collected data was analyzed using the SPSS statistical package. Result: Out of 15 categories on the communal shared housing, there were common preferences to 6 categories and differences in 7 categories between young adults and adults. At a time with the need for customized housing welfare by life cycle, these research findings are expected to provide basic data to realize customized housing welfare for the housing vulnerable and develop appropriate housing alternatives.

• Journal of the Korean Society for Railway
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• v.14 no.1
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• pp.73-79
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• 2011

This paper aims to find out the statistical characteristics of railroad weather-related accidents and incidents of each railroad line and then reduce the railroad accidents and prepare for the climate change. For this, we used data of KROIS and Korea railroad accidents report during 1996-2008. The results are as follows; Gyeongbu line is the most vulnerable line to railroad weather-related accidents, Yeongdong and Taebaek line are also the vulnerable line. The main railroad weather-related accidents and incidents is a railway obstruction and the next is a signal failure, a power supply failure. The second cause of a railway obstruction was some different for each line, but the main cause was a collapsed roadbed. We knew that the cold front accompanied with a heavy rainfall for a short time is the main weather pattern which cause the railroad accidents.

• Journal of the Korean Society of Safety
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• v.29 no.3
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• pp.98-106
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• 2014

This study proposes severity analysis for pedestrian accidents by improving variables which were used for general severity analysis. The existing variables were collected based on the interviews with policeman or witnesses and evidence of accidents. Therefore, existing variables were subjective and had several measurement errors. In order to improve such problems, this study collected variables from vehicle recorder of taxi which recorded the moment of accidents. As a result, explanatory power of independent variables was enhanced and the complete objective variables could be collected. After collecting variables, ordered probit model was developed by utilizing vehicle recorder database. Fitness of ordered probit model was 0.23. Vehicle speed and pedestrian's eye direction variables were the most critical factors for severity of pedestrian accident. In addition, severity analysis for vulnerable pedestrian was carried out. As a result, it was revealed that vehicle speed, pedestrian's eye direction and safety zone variables affected the severity of pedestrian accidents most. Particularly, vehicle speed variable is the most important factor. Consequently, driver's defensive driving and compliance to the regulations are the priority to reduce severity of pedestrian accidents and prevent pedestrian accident.

• Korean Journal of Computational Design and Engineering
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• v.22 no.2
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• pp.141-149
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• 2017

Vulnerability assesses the loss of major performance functions of GCV (Ground Combat Vehicles) when it is hit by enemy's shell. To decide the loss of major functions, it is determined what effects are on the performance of GCV when some components of GCV are failed. M&S (Modeling and Simulation) technology is used to vulnerability assessment. The hydro-pneumatic suspension is used as a sample part. The procedures of vulnerability assessment of the hydro-pneumatic suspension are shown as follows: 1) The components of the suspension are defined, and shot lines are generated evenly around the part. 2) The penetrated components are checked by using the penetration equation. 3) The function model of the suspension is designed by using IDEF0. 4) When the failure of the critical components of the suspension happens, its effect on the function of the suspension can be estimated using DMEA (Damage Mode and Effects Analysis). 5) The diagram of FTA (Fault Tree Analysis) is designed by exploiting DMEA. 6) The damage probability of the suspension is calculated by using FTA and vulnerable area method. In this paper, SLAP (Shot Line Analysis Program) which was developed based on COVART methodology. SLAP calculates the damage probability and visualizes the vulnerable areas of the suspension.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.6
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• pp.723-731
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• 2009

Recently, it has been strangely increasing rainfall and rainfall meter by global warming. so flood damage is being increase. It has happened there are so many damaged by influence by backwater of dam. However, the alleviative solutions of flood damages are focused on the lower river basin where the density of population is higher than upper river basin. This research proceeds based on design and build 3D topography model and reflects the topographical factors of upper river basin. It also simulated the circumstances of flooding by investigation of factors of outflow, hence, as a result, we would find out the vulnerable area for flooding and scale of damages effectively. This research suggests the solution and method of flooding for vulnerable area of the flooding to reduce the damages by predicting flooding. Thus, the suggestion may support to make a decision efficiently to prevent the damage of flooding.