• Journal of Internet Computing and Services
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• v.22 no.6
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• pp.91-97
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• 2021

The United States is responding to evolving cyberattacks through the Commercial Solutions for Classified Program (CSfC). Authorized safety evaluation and certification are being carried out so that US government agencies can quickly introduce civilian commercial security products into the national pavilion. Commercial security products registered in the CSfC process can be used by defense agencies through a rapid approval process. Defense agencies approve commercial security products without duplicate evaluation. Approved security products can reduce the time, cost, and cost of the approval process required to implement the defense information system. In this study, security control for 4 types of network security architecture MSC (Multi-Site Connectivity), MA (Mobile Access), Campus WLAN, and DAR (Data at Rest) proposed by the US National Security Agency (NSA) for introduction to national defense A detailed analysis was performed on the items.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1811-1825
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• 2011

This study analyzed the transit services with respect to transit service measures such as the load factor representing number of passengers between stops, dwelling time, and operational speed based on transit smart card data recorded in 2009. A case study on the local bus line 7024 connecting Seoul railway station to evaluate bus services at passenger perspectives was accomplished. From the results, we found that the dwelling time was not affected by the number of passengers which is because the tagging patterns are different among passengers. The operational speed was analyzed by calculating the average speed of the bus route and the speed of each bus stops based on dwelling time. Interestingly, calculating operation speed based on the transit smart card data is the first time effort ever made and this means that it is not necessary to observe travel speed of bus and railway at a field level any more. we hope that this study will be a basis of evaluation of transit services purely based on the transit smart card data and help to make better transit services for passengers and operators as well.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.4D
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• pp.547-553
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• 2011

This study has redefined the concepts of mobility indexes and potential demand, standards to evaluate areas with the worst public transportation system and applied the relevant indexes to select the areas with the worst public transportation mobility and present a method to set direct public transportation lines between these regions. The mobility indexes and indexes to evaluate potential demand were applied to select the regions with the worst public transportation systems in four metropolitan cities and case studies were carried out on direct lines provided between these regions. The analysis results showed that in public transportation mobility blind spots, public transportation takes much longer than driving an automobile or public transportation services are not provided. In addition, the analysis showed that a direct lines system to solve such worst off regions should be built to have public transportation take as much time as driving an automobile by establishing lines for automobiles only, minimize time lost from hopping up and down a bus and maximize connections.

• Journal of the Korean Geosynthetics Society
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• v.14 no.4
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• pp.1-9
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• 2015

According to national regulations and its commentary, such as Rivers Design Criteria & Commentary (KWRA, 2009), Foundation Structure Guideline and its Commentary(MLTM, 2014 and KGS, 2009), the integrity evaluation of river levee includes slope stability evaluation of both riverside/protected low-land and piping stability evaluation with respect to foundation and levee body along with water level conditions. In this case the design hydro-graph can be the most important input factor for the integrity evaluation, however it is fact that the national regulations do not provide any proper determination methods regarding hydro-graph. The authors thus executed an integrity evaluation of sluice gate in levee by changing each hydro-graph factor, including rising ordinary water level, lasting flood water level, falling water level, and flood frequency, in order to suggest a determination method of reasonable hydro-graph. As a result, the authors suggested that at least over 57 hours of rising ordinary water level and over 53 hours of lasting flood water level should be considered for the design hydro-graph of sluice gate in levee at Mun-san-jae.

• Journal of the Korean Geotechnical Society
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• v.30 no.4
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• pp.81-92
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• 2014

The integrity evaluation of river levee includes slope stability evaluation of riverside land and protected low-land, and safety of piping with respect to critical gradient and critical velocity based on related regulations, such as Design Criteria Rivers Commentary (2009), Structural Design Criteria Based Commentary (2009). The design hydro-graph is the most important design input factor for the integrity evaluation; it can be inaccurate due to the absence of its decision methods suggested by the national level. The authors in this paper evaluated numerical analytic levee integrity for piping and slope stability by changing each design hydro-graph, including rising ordinary water level, lasting flood water level, falling water level, and flood frequency for Mun-san-jae on Nak-dong River. Finally, the authors suggested that the levee integrity of piping and slope stability are very sensitive to the changes of increasing time of ordinary water level by 57 hours and lasting time of the flood water level by 53 hours, respectively, for Mun-san-jae.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.1
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• pp.147-156
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• 2017

This paper analyzes the performance limit of WAVE system for the platooning service requirements which is referred from the de facto standards. The performance of the packet error rate and mean delay as key parameters in the wireless communication systems should be satisfied to provide safety to the platooning vehicles. The test scenarios are conducted by considering the following vehicle groups: platooning vehicles, vehicles within a hop distance and vehicles within two hop distance( called hidden node vehicles). The models of packet error rate and delay deals with the topology of aforementioned vehicle groups, vehicle speed and communication range. The numerical results are obtained in terms of packet size, packet arrival rate and data transmission rate. Finally, this paper suggests the robust range of packet error rate and delay for the WAVE system to provide the platooning vehicle service.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.1
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• pp.50-63
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• 2017

While transit is inconvenient, it is also inevitable for the efficient public transportation. Reducing the number of transfers as much as possible is most important in providing the convenience of public transportation and facilitating the public transportation. As for the public transportation card data, 61,986 items on weekdays and 69,100 items on weekends were collected. Pattern analysis and traffic influence factors were analyzed using traffic data card. Trip chain results revealed that people have more transit transfers for shopping and leasure than commuting purposes on weekends and that commuting distance and time increase by 10 km and 9.9 minutes, respectively. Besides, results of the structural equation model showed that factor 1(total travel time, total travel distance), factor 2(number of people getting on and off), factor 3(transit time), and factor 4(number of bus connections, number of operations) were found to have significant effects on the number of transfers.

• The Journal of the Acoustical Society of Korea
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• v.23 no.6
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• pp.462-472
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• 2004

In this paper a method for compensating for thp performance degradation or automatic speech recognition (ASR) is proposed. which is mainly caused by speaking rate variation. Before the new method is proposed. quantitative analysis of the performance of an HMM-based ASR system according to speaking rate is first performed. From this analysis, significant performance degradation was often observed in the rapidly speaking speech signals. A quantitative measure is then introduced, which is able to represent speaking rate. Time scale modification (TSM) is employed to compensate the speaking rate difference between input speech signals and training speech signals. Finally, a method for compensating the performance degradation caused by speaking rate variation is proposed, in which TSM is selectively employed according to speaking rate. By the results from the ASR experiments devised for the 10-digits mobile phone number, it is confirmed that the error rate was reduced by 15.5% when the proposed method is applied to the high speaking rate speech signals.

• Korean Journal of Materials Research
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• v.3 no.3
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• pp.245-252
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• 1993

We investigated the changes of (U, Ce)$O_2$ powder characteristics with $CeO_2$ contents and ball-milling time and then studied on the sintering properties with those (U, Ce)$O_2$ powder characteristics. From the results of this study, it was concluded that the longer ball-milling time of (U, Ce)$O_2$ powder was, the finer its particle size was. Green and sintered densities were decreased with $CeO_2$ contensts increase. And also $CeO_2$ was recongized deteriorating oxide on the $UO_2$ sintering. In case of the lOwt. % $CeO_2$ contents, (U, Ce)$O_2$ sintered pellet which was made of ball-milled powder for 4 hours had few pores and its pores got near to the sphere. And its sintered density had the highest. Because its powder had higher surface area and its packing ratio was appropriated much better than others.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.4
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• pp.15-22
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• 2019

The use of modular buildings is increasing because of various advantages of modular buildings. But there are limits to apply modular buildings to medium-rise buildings because the building law provides only the specification criteria of the modular building with respect to the 1 hour fire resistance performance. This study was conducted to investigate 2 hours fire resistance performance of load bearing walls with steel studs in modular buildings by KS F 2257-1 and KS F 2257-4. After full scale tests, load bearing walls ensuring two hours fire resistance performance consist of at least 2 layers of fire resistance plaster boards of 19mm thickness or 3 layer of fire resistance plaster boards of thickness.