• Proceedings of the Korean Vacuum Society Conference
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• 2006.08a
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• pp.35-35
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• 2006

• Journal of the Korean Society of Safety
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• v.31 no.6
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• pp.121-128
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• 2016

Social Media transformed the mass media based information traffic, and it has become a key resource for finding value in enterprises and public institutions. Particularly, in regards to disaster management, the necessity for public participation policy development through the use of social media is emphasized. National Disaster Management Research Institute developed the Social Big Board, which is a system that monitors social Big Data in real time for purposes of implementing social media disaster management. Social Big Board collects a daily average of 36 million tweets in Korean in real time and automatically filters disaster safety related tweets. The filtered tweets are then automatically categorized into 71 disaster safety types. This real time tweet monitoring system provides various information and insights based on the tweets, such as disaster issues, tweet frequency by region, original tweets, etc. The purpose of using this system is to take advantage of the potential benefits of social media in relations to disaster management. It is a first step towards disaster management that communicates with the people that allows us to hear the voice of the people concerning disaster issues and also understand their emotions at the same time. In this paper, Korean language text mining based Social Big Board will be briefly introduced, and disaster issue detection model, which is key algorithms, will be described. Disaster issues are divided into two categories: potential issues, which refers to abnormal signs prior to disaster events, and occurrence issues, which is a notification of disaster events. The detection models of these two categories are defined and the performance of the models are compared and evaluated.

• Journal of Korea Multimedia Society
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• v.6 no.2
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• pp.288-300
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• 2003

As the importance of information security gets recognized seriously, ciphers technology gets used more. Particularly, since public key ciphers are easier to control the key than symmetric key ciphers and also digital signature is easily implemented, public key ciphers are increased used. Nowadays, public key infrastructure is established and operated to use efficiently and securely the public key ciphers. In the public key infrastructure, the user registers at the certificate authority to generate the private key and public key pair and the certificate authority issues the certificate on the public key generated. Through this certificate, key establishment between users is implemented and encryption communication becomes possible. But, control function of session key established in the public key infrastructure is not provided. In this thesis, the certificate issuing protocol to support the key recovery of the session key established during the wireless authentication and key establishment is proposed.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.2 no.1
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• pp.43-50
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• 2009

This paper caters the need of acquiring the principal objects, characters, and scenes from a video in order to entertain the image based query. The movie frames are divided into frames with 2D representative images called "key frames". Various regions in a key frame are marked as key objects according to their textures and shapes. These key objects serve as a catalogue of regions to be searched and matched from rest of the movie, using viewpoint invariant regions calculation, providing the location, size, and orientation of all the objects occurring in the movie in the form of a set of structures collaborating as video profile. The profile provides information about occurrences of every single key object from every frame of the movie it exists in. This information can further ease streaming of objects over various network-based viewing qualities. Hence, the method provides an effective reduced profiling approach of automatic logging and viewing information through query by example (QBE) procedure, and deals with video streaming issues at the same time.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.40 no.3
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• pp.137-143
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• 2003

Key frame extraction has been recognized as one of tile important research issues in video information retrieval. Although progress has been made in key frame extraction, the existing approaches do not evaluate the importance of extracted frame Quantitatively, and Dey are computationally expensive or ineffective. In this Paper, we introduce a new 미해rithm for key frame extraction using shot coverage and distortion. The algorithm finds significant key frames from candidate key frames. When selecting the candidate frames, the coverage rate to the total frames from each frame is computed by using the difference between the adjacent frames in tile shot. The frames within 10$\%$ from the top are selected as the candidates. Then, by comfuting the distortion rate of the candidates against all frames, pick the frames which arc most representative are selected. The performance of the proposed algorithm has been verified by a statistical test. Experiments show that more than 13-50$\%$ improvement has been obtained by the proposed algorithm compared to the existing methods.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.5
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• pp.2394-2406
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• 2016

ABE has become an effective tool for data protection in cloud computing. However, since users possessing the same attributes share the same private keys, there exist some malicious users exposing their private keys deliberately for illegal data sharing without being detected, which will threaten the security of the cloud system. Such issues remain in many current ABE schemes since the private keys are rarely associated with any user specific identifiers. In order to achieve user accountability as well as provide key exposure protection, in this paper, we propose a key-insulated ciphertext policy attribute based encryption with key exposure accountability (KI-CPABE-KEA). In our scheme, data receiver can decrypt the ciphertext if the attributes he owns match with the self-centric policy which is set by the data owner. Besides, a unique identifier is embedded into each user's private key. If a malicious user exposes his private key for illegal data sharing, his identity can be exactly pinpointed by system manager. The key-insulation mechanism guarantees forward and backward security when key exposure happens as well as provides efficient key updating for users in the cloud system. The higher efficiency with proved security make our KI-CPABE-KEA more appropriate for secure data sharing in cloud computing.

• Journal of Power Electronics
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• v.16 no.2
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• pp.717-730
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• 2016

The harmonic components of grid voltage result in oscillations of the calculated phase obtained via phase synchronization. This affects the security and stability of grid-connected converters. Moving average filter, delayed signal cancellation and their related harmonic elimination algorithms are major methods for such issues. However, all of the existing methods have their limitations in dealing with multiple harmonics issues. Furthermore, few studies have focused on a comparison and evaluation of these algorithms to achieve optimal algorithm selections in specific applications. In this paper, these algorithms are quantitatively analyzed based on the derived mathematical models. Moreover, an enhanced moving average filter and enhanced delayed signal cancellation algorithms, which are applicable for eliminating a group of selective harmonics with only one calculation block, are proposed. On this basis, both a comprehensive comparison and a quantitative evaluation of all of the aforementioned algorithms are made from several aspects, including response speed, required data storage size, sensitivity to sampling frequency, and elimination of random noise and harmonics. With the conclusions derived in this paper, better overall performance in terms of harmonic elimination can be achieved. In addition, experimental results under different conditions demonstrate the validity of this study.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.10
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• pp.5080-5097
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• 2017

Channel characteristics-based secret key generation is an effective physical-layer security method. The issues of how to remove the effect of random noise and to balance the key generation rate (KGR) and the bit mismatch rate (BMR) are needed to be addressed. In this paper, to reduce the effect of random noise and extract more secret bits, a new quantization scheme with high key generation rate and low bit mismatch rate is proposed. In our proposed scheme, we try to use all measurements and correct the differences caused by noise at the boundary regions instead of simply dropping them. We evaluate and discuss the improvements of our proposed scheme. The results show that our proposed scheme achieves lower bit mismatch rate as well as remaining high key generation rate.

• Land and Housing Review
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• v.5 no.3
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• pp.179-191
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• 2014

The purpose of this study is to employ a method called 'conflict impact assessment' to analyze the progress, background, cause and relevant issues of conflicts related with affordable housing for youth (Happiness Housing Project), a project that has been implemented since last May 2013, thereby identifying the relevant problems and draw out objectives for improvement. The researchers expect that this study will contribute to solving the current issues regarding Happiness Housing, and contribute to improving the quality of the government's policies. For the above purpose, literatures on Happiness Housing produced from August to November 2013 were reviewed, in-depth telephone or face-to-face interviews were conducted with personnel associated with project implementation in the Ministry of Land, Infrastructure and Transportation and LH, etc., and major interested parties including Yangcheon-gu residents. Key issues identified regarding Happiness Housing construction include: the way that the project was implemented, living quality of residents, impact on educational environment, inconsistence with existing plans, relatively high construction cost, insolvency of public corporations, land use fee issue with Korail, need of preliminary feasibility survey, securing sufficient amount for supply and issue of additional designation, likelihood of finishing construction in time and issues related with actual source of demand, etc. Through analysis of conflict development and positions of interested parties, the main causes of the conflicts were identified as follows: lack of deliberation on pledges during election, lack of viability review on pledges, lack of conflict management plans, one-way implementation without consent of interested parties, project plans established with no regard to local circumstances, frequent project revision, underwehlming level of conflict management. In order to address issues above, the following measures need to be taken: selecting election pledges based on actual effectiveness, thorough assessment on pledges by relevant departments, gradual implementation based on consideration of the actual circumstances, participation of key interested parties, consistent policy and adopting conflict management techniques that reflect the reality.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.2
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• pp.843-859
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• 2018

Cybersecurity has emerged as a serious problem in Korea and there have been relevant movements to improve domestic cybersecurity policy and system. However, discussions have yet to result in actual progress and the legislation for improvement of cybersecurity policy and system have been stagnant until now. As evidenced by the introduction of primary government legislation bill for national cybersecurity in 2017, the preparations for improvements to the policy and system are still in progress. However, we cannot be positive about the possibility of implementing these improvements during the process. Recognition of the importance of cybersecutiry has gradually risen and is more prevalent than in years past, however, in-depth discussions are not being made. In principle, misunderstandings about cybersecurity itself and insufficient understandings of the relevant legislation seem to cause such problems. Therefore, it is necessary to review key issues related to the improvement of cybersecurity policy and system and reconsider tasks for the future. Such issues include the relationship between cybersecurity and fundamental rights, establishing responsibility and capability of each of entities for cybersecurity, and the role of the military in cybersecurity. This type of in-depth discussion will be helpful for finding ways to improve upon cybersecurity policy and system. Moreover, this study aims to key issues with questionnaire survey and political and normative inquiry.