• Journal of Information Processing Systems
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• 제13권3호
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• pp.573-589
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• 2017

Cloud computing is an attractive solution that can provide low cost storage and powerful processing capabilities for government agencies or enterprises of small and medium size. Yet the confidentiality of information should be considered by any organization migrating to cloud, which makes the research on relational database system based on encryption schemes to preserve the integrity and confidentiality of data in cloud be an interesting subject. So far there have been various solutions for realizing SQL queries on encrypted data in cloud without decryption in advance, where generally homomorphic encryption algorithm is applied to support queries with aggregate functions or numerical computation. But the existing homomorphic encryption algorithms cannot encrypt floating-point numbers. So in this paper, we present a mechanism to enable the trusted party to encrypt the floating-points by homomorphic encryption algorithm and partial trusty server to perform summation on their ciphertexts without revealing the data itself. In the first step, we encode floating-point numbers to hide the decimal points and the positive or negative signs. Then, the codes of floating-point numbers are encrypted by homomorphic encryption algorithm and stored as sequences in cloud. Finally, we use the data structure of DoubleListTree to implement the aggregate function of SUM and later do some extra processes to accomplish the summation.

• 지식경영연구
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• 제18권2호
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• pp.129-157
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• 2017

Knowledge is important to both individuals and organizations. Individuals can have the opportunity to have bargaining power within their organisations by having knowledge of know-how and ideas. Having ample knowledge of the organization can bring about advantages in securing competitive advantage. Organization wants to encourage employees to share knowledge. Despite the efforts to enhance knowledge sharing, often the effort failed. Employees are unwilling to share their knowledge or hide their knowledge. The purpose of this study is to clarify the relationship between knowledge hiding and knowledge sharing based on exploring the influence factors of knowledge hiding and knowledge sharing. As a result, the influence factors of knowledge hiding and knowledge sharing were different. The influences of knowledge hiding influenced knowledge hiding only and did not affect knowledge sharing. This implies that knowledge hiding and knowledge sharing do not exist on a single line but exist independently of each other, such as 'Herzberg's two-factor theory'. This study suggests that knowledge hiding is a field of interest as well as knowledge sharing. In practice, it is suggested that the concept of promoting knowledge sharing is not a way to reduce knowledge hiding, so the two concepts should be managed separately.

• 한국통신학회논문지
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• 제41권11호
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• pp.1329-1340
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• 2016

최근 Zhang은 동기식 스트림 암호를 통해 암호화된 영상에 데이터를 은닉하는 방법을 제안하였다. 수신자는 먼저 암호화된 영상을 복호하고, 복호된 영상에 섭동 함수(fluctuation function)를 이용하여 공간 상관 특성 값을 계산함으로써 데이터를 추출한다. 그 후 Hong은 사이드 매치(side match) 기법을 이용하여 Zhang의 데이터 은닉 기법을 개선하였다. 본 논문에서는 데이터 추출과정에서 발생하는 오류를 감소시키기 위해 새로운 섭동 함수를 제안하고, 표본 영상들에 대한 컴퓨터 모의실험을 통해 제안하는 기법이 기존의 방법들보다 우수함을 검증하였다.

• 복식문화연구
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• 제8권6호
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• pp.871-886
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• 2000

The purpose of this study is to understand the culture on the Traditional Wedding of the West Gyeong Nam District. The traditional wedding was characterized that the bridegroom visited his bride's house accompanied by his honored guests(上客) and the marriage ceremony was to be held in day time, and then the bridegroom became a son-in-law and stayed with the family for a few days. The bridegroom returned to his home, leaving his bride behind. After a certain period, the bride came to her husband's home as a daughter-in-law. The Traditional Wedding costume of the bridegroom were Samo-Gwandae. The coat (outside uniform) was blue Danryeong ornamented with two cranes figured Hyong-Bae and Heukgackdae. In case Samo-Gwandae was not available, Dopo or Durumakie could be substituted and they put on shoes in this case. A bridegroom put on Mokhwa his feet and under the Samo, and he also put on Nambawie or Bokguen. He put on Dopo or Haeng-eui(行衣) or Durumaki under the blue Danryeong. The bride put on Wonsam and Chokduri or Hwagwan on her hair. In case Wonsam was not available, Chima Jogori style or imitational Wonsam, which was roughly sewed with red cloth and blue cloth contained in the Honsuham (Box of wedding treasure), could be substituted. She put on Hyang-guen to protect her body against the coldness and to hide her face.

• Journal of Advanced Marine Engineering and Technology
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• 제36권5호
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• pp.645-661
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• 2012

Recently, pirates are infesting on the sea and they have been hijacking the several vessels for example Samho Dream and Samho Jewelry of Korea. One of the items to reduce the risk is to adopt the invader detection system. If the pirates break in to the ship, the detection system can monitor the pirates and then call the security alarm. The crew can gain time to hide to the safe room and the report can be automatically sent to the control room to cope with the situation. For the invader detection, an unmanned observation system was proposed using the image detection algorithm that extracts the invader image from the recording image. To detect the motion area, the difference value was calculated between the current image and the prior image of the invader, and the 'AND' operator was used in calculated image and edge line. The image noise was reduced based on the morphology operation and then the image was transformed into morphological information. Finally, a neural network model was applied to recognize the invader. In the experimental results, it was confirmed that the proposed approach can improve the performance of the recognition in the invader monitoring system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권2호
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• pp.405-424
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• 2013

In publishing applications, it is advantageous to embed data in halftone images. The CPT scheme (Chen-Pan-Tseng, 2000) is a steganographic data hiding scheme that was proposed for binary images, e.g., facsimiles. The CPT scheme uses a secret key and weight matrix to protect the hidden data and can hide as many as $r={\lfloor}{\log}_2(m{\times}n+1){\rfloor}$ bits of data in the image by changing at most 2 bits in the image. Our proposed scheme also uses a secret key to protect it from being compromised and a weight matrix to increase the data hiding rate. Our scheme improves the performance of the CPT scheme by using the simple principle of splitting each block into two parts. Our proposed scheme is called improved CPT (ICPT) and has a very high embedding capacity compared to previous schemes. Experimental results demonstrate that our proposed scheme generally has higher performance than previous schemes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권9호
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• pp.4568-4584
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• 2016

Steganography based on text generation has become a hot research topic in recent years. However, current text-generation methods which generate texts of normal style have either semantic or syntactic flaws. Note that texts of special genre, such as poem, have much simpler language model, less grammar rules, and lower demand for naturalness. Motivated by this observation, in this paper, we propose a text steganography that utilizes Markov chain model to generate Ci-poetry, a classic Chinese poem style. Since all Ci poems have fixed tone patterns, the generation process is to select proper words based on a chosen tone pattern. Markov chain model can obtain a state transfer matrix which simulates the language model of Ci-poetry by learning from a given corpus. To begin with an initial word, we can hide secret message when we use the state transfer matrix to choose a next word, and iterating until the end of the whole Ci poem. Extensive experiments are conducted and both machine and human evaluation results show that our method can generate Ci-poetry with higher naturalness than former researches and achieve competitive embedding rate.

• 한국해양공학회지
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• 제25권4호
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• pp.59-65
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• 2011

In structural health monitoring (SHM) using electro-mechanical impedance signatures, it is a critical issue for extremely large structures to extract the best damage diagnosis results, while minimizing unknown environmental effects, including temperature, humidity, and acoustic vibration. If the impedance signatures fluctuate because of these factors, these fluctuations should be eliminated because they might hide the characteristics of the host structural damages. This paper presents a long-term SHM technique under an unknown noisy environment for tidal current power plant structures. The obtained impedance signatures contained significant variations during the measurements, especially in the audio frequency range. To eliminate these variations, a continuous principal component analysis was applied, and the results were compared with the conventional approach using the RMSD (Root Mean Square Deviation) and CC (Cross-correlation Coefficient) damage indices. Finally, it was found that this approach could be effectively used for long-term SHM in noisy environments.

• 전기학회논문지
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• 제67권2호
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• pp.270-276
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• 2018

Apache Spark is one of the high performance in-memory computing frameworks for big-data processing. Recently, to improve the performance, general-purpose computing on graphics processing unit(GPGPU) is adapted to Apache Spark framework. Previous Spark-GPGPU frameworks focus on overcoming the difficulty of an implementation resulting from the difference between the computation environment of GPGPU and Spark framework. In this paper, we propose a Spark framework based on a heterogenous pipeline computing with OpenCL to further improve the performance. The proposed framework overlaps the Java-to-Native memory copies of CPU with CPU-GPU communications(DMA) and GPU kernel computations to hide the CPU idle time. Also, CPU-GPU communication buffers are implemented with switching dual buffers, which reduce the mapped memory region resulting in decreasing memory mapping overhead. Experimental results showed that the proposed Spark framework based on a heterogenous pipeline computing with OpenCL had up to 2.13 times faster than the previous Spark framework using OpenCL.

• 정보처리학회논문지:컴퓨터 및 통신 시스템
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• 제2권5호
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• pp.223-230
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• 2013

IT기술의 급속한 발전으로 인해 인터넷 상에서 많은 사람들이 메신저를 이용해 실시간으로 대화를 나누거나 업무처리를 위한 파일 공유 등에 메신저를 사용하고 있다. 하지만 이런 편리성을 이용해 금전 요구 등의 메신저 피싱 범죄가 발생하고 있으며, 범죄자가 자신이 접속한 IP 주소를 은닉하기 위하여 Proxy와 같은 우회기법을 사용할 경우 범죄자의 Real IP 주소를 확인하는 것은 어려운 실정이다. 본 논문은 ARIT 기법을 이용해 2채널 방식으로 접속 IP 주소와 ARIT Agent를 이용해 얻은 Real IP 주소를 수집하여 별도의 확인 과정을 거친 후, 사용자가 정상적인 방법으로 접속했는지 여부를 판단하여 사전에 발생할 수 있는 메신저 피싱에 대응할 수 있는 방안에 대해 제시하고자 한다.