• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.138-141
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• 2004

The environmental tracers tritium/helium-3 (3H/3He) and chlorofluorocarbons (CFCs) were investigated in ground water from Jeju Island, Korea, a basaltic volcanic island. The apparent 3H/3He and CFC-12 ages were in relatively good agreement in samples with low concentrations of terrigenic He. Ground water mixing was evaluated by comparing 3H and CFC-12 concentrations with mixing models, which distinguished old water with negligible 3H and CFC-12, young water with piston flow, and binary mixtures of the two end members. The ground water CFC-12 age is much older in water from wells completed in confined zones of the hydro-volcanic Seoguipo formation in coastal areas than in water from the basaltic aquifer. Comparison of major element concentrations in ground water with the CFC-12 age shows that nitrate contamination processes contribute more solutes in young water than are derived from water-rock interactions in non-contaminated old water. Chemical evolution of ground water resulting from silicate weathering in basaltic rocks reaches the zeolite-smectite phase boundary. The calcite saturation state of ground water increased with the CFC-12 apparent (piston flow) age. In agricultural areas, the temporal trend of nitrate concentration in ground water was consistent with the known history of chemical fertilizer use on Jeju Island, but the response of nitrate concentration in ground water to nitrogen inputs follows an approximate 10-year delay. Based on mass balance calculations, it was estimated that about 40% of the nitrogen applied by fertilizers reached the water table and contaminated ground water resources when the fertilizer use was at the highest level.

• Convergence Security Journal
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• v.15 no.4
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• pp.3-9
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• 2015

A web application that allows a web service created by a internal developer who has security awareness show certain level of security. However, in the case of development by outsourcing, it is inevitable to implement the development centered on requested function rather than the issue of security. Thus in this paper, we improve the software testing process focusing on security for exclusion the leakage of important information and using an unauthorized service that results from the use of the vulnerable web application. The proposed model is able to consider security in the initial stage of development even when outsourced web application, especially, It can prevent the development schedule delay caused by the occurrence of modification for program created by programer who has low security awareness. This result shows that this model can be applied to the national defense area for increasing demand web application centered resource management system to be able to prevent service of web application with security vulnerability based on high test.

• Journal of Korea Multimedia Society
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• v.13 no.1
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• pp.111-121
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• 2010

Since SMEs have recognized needs for industrial technique leakage prevention, they tend to construct information security system causing huge consumption of budget, yet they cannot organize information security team to operate integrated information security management system with consistency and it is fact that there only occur instant introductions of certain system. In this study, we designed information security management system for SMEs' industrial technique leakage prevention which is differentiated from those of large enterprises based on current status of SMEs' industrial technique leakage. Specifically we analyzed current status and vulnerability of SMEs' industrial technique leakage and we designed industrial technique leakage prevention management system for SMEs. Then we applied Delphi method to validate appropriateness of study result. We strongly believe that SMEs may estimate a appropriate level of investment on information security and develop countermeasures for control by utilizing this study result.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.5
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• pp.1303-1315
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• 2012

In the draft of the IEEE 802.11s standard, a tree topology is established by the proactive tree-building mode of the Hybrid Wireless Mesh Protocol (HWMP). It is used for cases in which the root station (e.g., gateway) is an end point of the majority of the data connections. In the tree topology, the root or central stations (e.g., parent stations) are connected to the other stations (e.g., leaves) that are one level lower than the central station. Such mesh stations are likely to suffer heavily from contention in bottleneck links when the network has a high traffic load. Moreover, the dependence of the network on such stations is a point of vulnerability. A failure of the central station (e.g., a crash or simply going into sleep mode to save energy) can cripple the whole network in the tree topology. This causes performance degradation for end-to-end transmissions. In a connected mesh topology where the stations having two or more radio links between them are connected in such a way that if a failure subsists in any of the links, the other link could provide the redundancy to the network. We propose a scheme to utilize this characteristic by organizing the network into concentric tiers around the root mesh station. The tier structure facilitates path recovery and congestion control. The resulting mode is referred to as Tier-based Proactive Path Selection Mode (TPPSM). The performance of TPPSM is compared with the proactive tree mode of HWMP. Simulation results show that TPPSM has better performance.

• Fire Science and Engineering
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• v.30 no.3
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• pp.48-54
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• 2016

Pilotis are support columns that lift a building above the ground. Thus, they can elevate the lowest floor to the secondfloor level and, in Korea, are used to leav a parking area below multifamily housing. However, if there is a fire in the piloti area, the cars and main entrance door are wrapped in flames. Due to the inflammability of the materials, the combustion of the cars and insulation at the ceiling of the pilotis, having a high heat release rate, can quickly destroy the front entrance of the building and spread heat, flames and a poisonous gas to the stairs and elevator pit. Therefore, the fire can quickly spread to the whole building, putting the lives of the residents in danger. This study was an in-depth accidental case study of the "Uijeongbu Fire Accident" that killed 5 residents and injured 139 others. The study identified the relationships between the fire at the piloti structure of multifamily housing and the vulnerability of this structure and its inherent weaknesses.

• Journal of the Korea Society of Computer and Information
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• v.11 no.5 s.43
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• pp.241-250
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• 2006

Regarding a spam attack and the interception that a spinoff is largest among weakness of VoIP service at these papers study. Write scenario of a spam attack regarding VoIP service, and execute Call spam, Instant Messaging spam, Presence spam attack. A spam attack is succeeded in laboratories, and prove, and confirm damage fact of a user in proposals of a spam interception way of VoIP service, 1) INVITE Request Flood Attack 2) Black/White list, 3) Traceback, 4) Black Hole-Sink Hole, 5) Content Filtering, 6) Consent based Communication, 7) Call act pattern investigation, 8) Reputation System Propose, and prove. Test each interception plan proposed in VoIP networks, and confirm security level of a spam interception. Information protection of VoIP service is enlarged at WiBro, BcN, and to realize Ubiquitous Security through result of research of this paper contribute, and may make.

• Advanced Composite Materials
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• v.17 no.3
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• pp.277-299
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• 2008

High quality and expedient processing repair methods are necessary to enhance the service life of bridge structures. Deterioration of concrete can occur as a result of structural cracks, corrosion of reinforcement, and freeze.thaw cycles. Cost effective methods with potential for field implementation are necessary to address the issue of the vulnerability of bridge structures and how to repair them. Most infrastructure related applications of fiber-reinforced plastics (FRPs) use traditional hand lay-up technology. The hand lay-up is tedious, labor-intensive and relies upon personnel skill level. An alternative to traditional hand lay-up of FRP for infrastructure applications is Vacuum Assisted Resin Transfer Molding (VARTM). VARTM uses single sided molding technology to infuse resin over fabrics wrapping large structures, such as bridge girders and columns. There is no work currently available in understanding the interface developed, when VARTM processing is adopted to wrap fibers such as carbon and/or glass over concrete structures. This paper investigates the interface formed by carbon fiber processed on to a concrete surface using the VARTM technique. Various surface treatments, including sandblasting, were performed to study the pull-off tensile test to find a potential prepared surface. A single-lap shear test was used to study the bond strength of CFRP fabric/epoxy composite adhered to concrete. Carbon fiber wraps incorporating Sikadur HEX 103C and low viscosity epoxy resin Sikadur 300 were considered in VARTM processing of concrete specimens.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.9B
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• pp.1330-1341
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• 2010

Power analysis (PA) is known as a powerful physical attack method in the field of information security. This method uses the statistical characteristics of leaked power consumption signals measured from security devices to reveal the secret keys. However, when measuring a leakage power signal, it may be easily distorted by the noise due to its low magnitude values, and thus the PA attack shows different performances depending on the noise level of the measured signal. To overcome this vulnerability of the PA attack, we propose a noise-reduction method based on wavelet de-noising. Experimental results show that the proposed de-noising method improves the attack efficiency in terms of the number of signals required for the successful attack as well as the reliability on the guessing key.

• Journal of Sasang Constitutional Medicine
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• v.26 no.3
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• pp.304-317
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• 2014

Objectives The purpose of this study was to find out whether there were differences of urticaria's disease aspect between patients classified into Sasang Constitution Types(SCTs) and whether those differences could be associated with Ordinary symptoms. Methods Medical records and questionnaires about 117 patients who visited one Korean medicine hospital due to urticaria were collated and statistically analyzed. Results 1) Ages 20 to 30, women, Soeumin(SE) and patients in conditions of chronic urticaria over 6 weeks were the majority among 117 patients in this study. Food and stress were most chosen as the main cause of urticaria. 2) Soyangin(SY) showed more severe symptoms of urticaria than other SCTs. In particular, the severity of pruritus, distribution of lesions and vulnerability to stress was statistically significant compared to other SCTs(p<0.05). SE expressed urticaria's symptoms at the medium-level of SY's and Taeeumin(TE)'s. TE exhibited relatively weak symptoms but TE only had slightly higher number of patients with angioedema compared to other SCTs. Taeyangin(TY) was only one case so more researches are needed. 3) In dispositional symptoms, SY had low quality of sleep and defecation. SE could not digest oily food well, felt dizzy and cold well, and had cold hands and feet. TE could eat and sweat much and tended to snore well. Conclusions In this study, urticaria had common cause of both stress and food in all SCTs but onset and severity of symptoms were different between SCTs. It could interpreted that these differences between SCTs were associated with ordinary symptoms native to each SCT.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.5B
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• pp.386-394
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• 2008

Adoption of wireless communication facilities in mobile devices leads to increased vulnerability in individual privacy. One of such cases was discovered when a smart mobile phone of Paris Hilton at Oscar Award Ceremony was hacked a Swedish group of hackers. In this study, I wondered what sort of personal information could be exposed to hackers in such cases. In the course of survey, it was recognized that technical analysis of flash memory in mobile devices to check what kinds of data are stored there is technically almost impossible, since they are usually built in a proprietary manner. No generic tools could apply to discover their contents. Having recognized technical difficulties, it was inevitable to resort to a questionnaire survey to see awareness level with regard to personal privacy. We collected response from three hundred respondents by posting the questionnaire at World Survey on-line research site. What we have discovered was quite astonishing that even personal residence registration numbers have been found from nine of every ten respondents. Other data revealed include phone numbers, names, and personal bank accounts.