• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.2
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• pp.107-120
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• 2019

In this study, the characteristics of watershed and pollution source were investigated in SoOakcheon located in the upper stream of Daecheong Lake. The Dimension Index method was applied to index various watershed and pollution source data. The influence factors of each pollutant source were derived through correlation analysis between selected index and water quality monitoring data. BOD and COD were significantly influenced by population density and land area ratio, T-N by CN and rice area ratio, and T-P by population density and land area ratio, respectively. The discharge load is often used to establish non-point source countermeasures, but there is a difference between the water load and the water load in the lake or river. Therefore, in order to manage non-point pollution efficiently, it is necessary to analyze influential factors with high correlation with water quality and to manage the relevant factors with priority.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.504-509
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• 2019

Recently, both wireless communications technology and the performance of small devices have developed exponentially, while the number of services using various types of Internet of Things (IoT) devices has also massively increased in line with the ongoing technological and environmental changes. Furthermore, ever more devices that were previously used in the offline environment-including small-size sensors and CCTV-are being connected to the Internet due to the huge increase in IoT services. However, many IoT devices are not equipped with security functions, and use vulnerable open source software as it is. In addition, conventional network equipment, such as switches and gateways, operates with vulnerabilities, because users tend not to update the equipment on a regular basis. Recently, the simple vulnerability of IoT devices has been exploited through the distributed denial of service (DDoS) from attackers creating a large number of botnets. This paper proposes a system that is capable of identifying Internet-connected devices quickly, analyzing and managing the vulnerability of such devices using Internet-wide scan technology. In addition, the vulnerability analysis rate of the proposed technology was verified through collected banner information. In the future, the company plans to automate and upgrade the proposed system so that it can be used as a technology to prevent cyber attacks.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.4
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• pp.145-166
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• 2023

The ongoing COVID-19 pandemic has led to a widespread shift towards non-face-to-face/uncrewed services in various sectors of society. Despite this, research on the digital divide has focused predominantly on analyzing various factors, with the notable absence of studies addressing the digital divide. Therefore, study examined the current digital divide in the transportation sector through a survey-based approach. First, a nationwide survey was conducted among adult men and women to assess their digital device usage. Vulnerable groups sesceptible to digital disparities were identified based on factors such as age, education, and income. Second, comparative analysis was conducted to examine the usage patterns of mobile applications related to the transportation sector among the vulnerable and non-vulnerable groups using chi-squared test. These findings suggest that the vulnerable group exhibited lower awareness and preference for mobile applications, a significantly lower frequency of application usage than the non-vulnerable group. Finally, a comparison of the proficiency in utilizing transportation sector mobile applications was conducted, showing that the vulnerable group demonstrated a significantly lower level of proficiency across all aspects of application usage procedures compared to the non-vulnerable group. These survey results provide a valuable foundation for future policy formulation to reduce the digital divide in the transportation sector. By highlighting the current state of digital disparities, the research contributes to developing evidence-based strategies to enhance inclusivity and equal access to digital services in tjwtransportation.

• The Korean Journal of Applied Statistics
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• v.27 no.1
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• pp.21-30
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• 2014

Ordinary survival analysis cannot be applied when a significant fraction of patients may be cured. A cure rate model is the combination of cure fraction and survival model and can be applied to several types of cancer. In this article, the cure rate model is considered in the interval censored data with a cluster effect. A shared frailty model is introduced to characterize the cluster effect and an EM algorithm is used to estimate parameters. A simulation study is done to evaluate the performance of estimates. The proposed approach is applied to the smoking cessation study in which the event of interest is a smoking relapse. Several covariates (including intensive care) are evaluated to be effective for both the occurrence of relapse and the smoke quitting duration.

• Convergence Security Journal
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• v.6 no.1
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• pp.45-53
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• 2006

It has been proposed that several RFID authentication protocols based on hash chain. Status based authentication protocol and challenge-response based authentication protocol are secured against location tracking attacks, spoofing attacks, replay attacks, traffic analysis attacks but are vulnerable to Dos attacks. RFID authentication protocol with strong resistance against traceability and denial of service attack is secured against location tracking attack, spoofing attacks, replay attacks, DoS attacks but are vulnerable to traffic analysis attacks. The present study suggests a more secure and lightweight RFID authentication protocol which is combining the advantages of hash-chain authentication protocol and RFID authentication protocol with strong resistance against traceability and denial of service attack. The results of the secure analysts for a proposed protocol are illustrated that it is secured against location tracking attacks, spoofing attacks, replay attacks, traffic analysis attacks, Dos attacks and is a lightweight operation between server and tag.

• Journal of KIISE:Computer Systems and Theory
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• v.37 no.4
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• pp.226-238
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• 2010

OpenSSL is an open-source library implementing SSL that is a secure communication protocol. However, the library has a severe vulnerability that its security information can be easily exposed to malicious software when the library is used in a form of shared library on Linux and UNIX operating systems. We propose a scheme to attack the vulnerability of the OpenSSL library. The scheme injects codes into a running client program to execute the following attacks on the vulnerability in a SSL handshake. First, when a client sends a server a list of cryptographic algorithms that the client is willing to support, our scheme replaces all algorithms in the list with a specific algorithm. Such a replacement causes the server to select the specific algorithm. Second, the scheme steals a key for data encryption and decryption when the key is generated. Then the key is sent to an outside attacker. After that, the outside attacker decrypts encrypted data that has been transmitted between the client and the server, using the specified algorithm and the key. To show that our scheme is realizable, we perform an experiment of collecting encrypted login data that an ftp client using the OpenSSL shared library sends its server and then decrypting the login data.

• Journal of Wetlands Research
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• v.20 no.4
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• pp.370-382
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• 2018

The purpose of this study is to quantitatively and effectively evaluate the factors affecting flood damage by watershed. National Water Resource Plan(MOCT, 2001) has been developed Potential Flood Damage(PFD) which indicates flood vulnerability. But, it is only a simple grouping and it does not provide guidelines for flood control planning based on detailed evaluation of sub-components. In this study, we used PFD in the Han River basin according to the method applied in the National Water Resource Plan (existing method) and improvement based on actual flood hazard area and data. As an application method, after analyzing by yearly change(2009~2014), we compared and analyzed the tendency of the sub - components that constitute the potential and risk rather than the current grouping. As the result, it was possible to accurately evaluate the existing and improved methods, and it was possible to derive the vulnerability rankings, but the existing methods have different results from the actual watershed tendency. Therefore, the PFD of the improvement method that correctly reflects past history and watershed characteristics is more appropriate for the evaluation of flood vulnerability in the watershed. In addition, it is reasonable to establish a flood control plan referring to this and prevent flood damage in advance.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.04a
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• pp.981-984
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• 2015

최근 온라인 마케팅 트렌드는 개인화된 서비스의 제공이다. 인터넷 환경의 대중화와 SNS(Social Networking Service), 모바일 환경의 보급으로 사용자는 쉽게 정보에 노출된다. 이런 환경에서 웹사이트나 애플리케이션, SNS에 대해 사용자의 패턴과 관심사를 분석하여 개인화된 서비스를 제공하게 된다. 데이터 분석은 빅 데이터 환경으로 분석되며 이렇게 분석된 개인화 정보는 사용자와 연관성이 높은 정보를 노출함으로 인해 효율적인 정보의 소비와 더불어 마케팅 효과를 누릴 수 있고, 온라인 서비스나 애플리케이션 제공자에게 사용자도 모르게 제공된 개인의 정보 소비 패턴으로 나타내어진다. 현재 널리 사용되고 있는 서버에 저장된 개인화 데이터는 보안적으로 해킹에 취약할 수 있고, 관리하는 서비스 제공자에게 있어서도 유지보수에 비용이 발생함과 동시에 사용자의 개인정보를 과도하게 수집하게 되는 우려가 나타난다. 개인화 서비스 제공의 단점을 극복하고자 HTML5 Local-Storage 기능을 사용하여 브라우저 환경에서 웹 기반 서비스를 이용하는 사용자의 정보이용 패턴을 저장하여 데이터를 사용자 측면의 저장소에 보관함으로 보다 안전하고 적은 비용으로 개인화 서비스를 제공할 수 있다.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.396-396
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• 2019

습지는 가장 생산적인 생태계 중 하나이며, 인류에게 수문학적, 경제적, 문화적 가치로도 매우 귀중한 역할을 하고 있다. 하지만 기후변화와 인간의 영향으로 수위저하와 건조, 수문체계에 변화를 주어 습지의 건조화 현상이 나타나고 이로 인해 생태계에도 영향을 미치고 있다. 특히 산지습지는 인위적 간섭에 매우 취약하고 환경변화에 민감하여 불규칙한 강수패턴 및 무분별한 개발은 습지수문환경에 영향을 미쳐 습지의 건조화를 심화시키는 원인이 되고 있다. 그 결과 자연적으로 습지의 면적이 감소하고 식생의 패턴 변화로 다양한 생물들과 보호가 필요한 종들이 사라질 것이므로 변화에 대응하기 위해서 건조화를 방지할 필요가 있다. 따라서 본 연구에서는 습지 내 지하수위 저하 또는 유입 유출량의 변화로 습지 토양의 수분이 감소하여 말라가는 현상을 습지 가뭄이라 정의하고 가뭄지수를 활용하여 이를 지수화 하였다. 현재 산지습지를 대상으로 가뭄을 지수화 시킨 선행연구가 거의 없기 때문에 향후 산지 습지의 가치를 보존하고 생태계 관리의 목적으로 후속 연구의 방향을 제시하는데 도움을 줄 것으로 예상된다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.5B
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• pp.415-429
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• 2011

Quantitative evaluation indexes for flood control effect of a multi-purpose reservoir used widely in Korea are the discharge control rate, reservoir release rate, reservoir storage rate, and flood control storage utilization rate. Because these indexes usually use and compare inflow, release, and storage data directly, the uncertainties included in these data are not considered in evaluation process, and the downstream flood control effects are not assessed properly. Also, since the acceptable partial failure in a design of water resources system is not considered, the development of a new flood control effect evaluation index is required. Fuzzy set theory is therefore applied to the development of the index in order to consider the data uncertainty, the downstream flood control effect, and the acceptable partial failure. In this study, the flood control effect of a multi-purpose reservoir is evaluated using the flood control effect index developed by applying fuzzy set theory. The Chungju reservoir basin was selected as a study basin and the storm events of July, 2006 are used to study the applicability of the developed index. The related factors for flood control effect are fuzzified, the acceptable failure region is divided from the system state to evaluate the flood control effect using developed flood control effect index. The flood control effect index were calculated by applying to the study basin and storm events. The results show that the developed index can represent the flood control effect of a reservoir more realistically and objectively than the existing index.