• Journal of the Korean Society of Clothing and Textiles
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• v.31 no.5 s.164
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• pp.670-679
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• 2007

Contemporary consumers interested in fashion develop global tastes regarding consumption and senses on how much certain products cost in the global market place. Demand for foreign brands and products produced a new type of e-tailor called surrogate Internet shopping malls. Due to the unfamiliarity of such retailers, consumers may perceive different types of risks and may show different styles of seeking informations. The research interest of this study was to investigate the differences of risk perception and information search between surrogate e-mall shoppers and general e-mall shoppers. In addition, we examined the influence of these two variables on consumer satisfaction. A survey questionnaire was developed. Measures of three types of e-shopping risks (delivery, transaction, service), information search and satisfaction were included. Data from surrogate e-mall consumers and general e-mall consumers were statistically analyzed. Surrogate e-mall shoppers showed a higher level of product delivery risk and customer service risk than general e-mall shoppers. They also spend more time in seeking information before making purchases. Regression analysis showed that perceived risk had significant influence on information search and consumer satisfaction for surrogate e-mall shoppers, whereas for general e-mall shoppers, no significant influence was detected. The findings should assist marketers and academics in their understanding of the surrogate e-shopping malls.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.6
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• pp.1311-1326
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• 2010

Peer-to-peer (P2P) networks consume the most bandwidth in the current Internet and file sharing accounts for the majority of the P2P traffic. Thus it is important for a P2P file sharing application to be efficient in bandwidth consumption. Bandwidth consumption as much as downloaded file sizes is inevitable, but those in file search and bad downloads, e.g. wrong, corrupted, or malicious file downloads, are overheads. In this paper, we target to reduce these overheads even in the presence of high volume of malicious users and their bad files. Sybil attacks are the example of such hostile environment. Sybil attacker creates a large number of identities (Sybil nodes) and unfairly influences the system. When a large portion of the system is subverted, either in terms of the number of users or the number of files shared in the system, the overheads due to the bad downloads rapidly increase. We propose ELiSyR, a file search protocol that can tolerate such a hostile environment. ELiSyR uses social networks for P2P file search and finds benign files in 71% of searches even when more than half of the users are malicious. Furthermore, ELiSyR provides similar success with less bandwidth than other general efforts against Sybil attacks. We compare our algorithm to SybilGuard, SybilLimit and EigenTrust in terms of bandwidth consumption and the likelihood of bad downloads. Our algorithm shows lower bandwidth consumption, similar chances of bad downloads and fairer distribution of computation loads than these general efforts. In return, our algorithm takes more rounds of search than them. However the time required for search is usually much less than the time required for downloads, so the delay in search is justifiable compared to the cost of bad downloads and subsequent re-search and downloads.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.1
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• pp.77-87
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• 2008

Recently, many hash-based authentication protocols were presented to guarantee mutual authentication between tag and DB in RFID system. To be suitable for distributed DB environment, one generally uses fixed constant value as a tag ID. However, some existing protocols have security flaws or heavy computational loads in DB in order to search a tag ID. We propose a secure authentication protocol which is suitable for distributed DB environment by using unchangeable tag ID. The storage method of pre-synchronized information in DB at previous session is core idea of our proposal which gives low-cost ID search of DB at next session. In normal synchronization state, our protocol only requires 3 hash operations in tag and DB respectively.

• Journal of Computing Science and Engineering
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• v.1 no.2
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• pp.177-194
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• 2007

Index selection is one of the most important decisions to take in the physical design of relational data warehouses. Indices reduce significantly the cost of processing complex OLAP queries, but require storage cost and induce maintenance overhead. Two main types of indices are available: mono-attribute indices (e.g., B-tree, bitmap, hash, etc.) and multi-attribute indices (join indices, bitmap join indices). To optimize star join queries characterized by joins between a large fact table and multiple dimension tables and selections on dimension tables, bitmap join indices are well adapted. They require less storage cost due to their binary representation. However, selecting these indices is a difficult task due to the exponential number of candidate attributes to be indexed. Most of approaches for index selection follow two main steps: (1) pruning the search space (i.e., reducing the number of candidate attributes) and (2) selecting indices using the pruned search space. In this paper, we first propose a data mining driven approach to prune the search space of bitmap join index selection problem. As opposed to an existing our technique that only uses frequency of attributes in queries as a pruning metric, our technique uses not only frequencies, but also other parameters such as the size of dimension tables involved in the indexing process, size of each dimension tuple, and page size on disk. We then define a greedy algorithm to select bitmap join indices that minimize processing cost and verify storage constraint. Finally, in order to evaluate the efficiency of our approach, we compare it with some existing techniques.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.12C
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• pp.1231-1238
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• 2005

This paper presents a new fast encoding algorithm for image vector quantization that incorporates the partial distances of multiple features with a multidimensional look-up table (LUT). Although the methods which were proposed earlier use the multiple features, they handles the multiple features step by step in terms of searching order and calculating process. On the other hand, the proposed algorithm utilizes these features simultaneously with the LUT. This paper completely describes how to build the LUT with considering the boundary effect for feasible memory cost and how to terminate the current search by utilizing partial distances of the LUT Simulation results confirm the effectiveness of the proposed algorithm. When the codebook size is 256, the computational complexity of the proposed algorithm can be reduced by up to the $70\%$ of the operations required by the recently proposed alternatives such as the ordered Hadamard transform partial distance search (OHTPDS), the modified $L_2-norm$ pyramid ($M-L_2NP$), etc. With feasible preprocessing time and memory cost, the proposed algorithm reduces the computational complexity to below the $2.2\%$ of those required for the exhaustive full search (EFS) algorithm while preserving the same encoding quality as that of the EFS algorithm.

• International Journal of Human Ecology
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• v.15 no.2
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• pp.59-67
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• 2014

Consumer information influences purchasing behavior; however, less is known about the relationship in the credit market. Credit markets offer consumers a complex array of different products when choosing mortgages. The current study examines whether borrowers search for the very best terms when making major decisions about borrowing money or obtaining credit as well as explores the relation between consumer information seeking and the cost of credit. This study demonstrates the existence of price dispersion between those who made an extensive information seeking and those who did not. When controlling for the proxies of creditworthiness and demographics of the respondents, it is found that those who made a great deal of information seeking tend to have lower mortgage rates than those who made almost no information seeking. This study offers financial educators and policy makers suggestions on how to help consumers make better financial decisions.

• International Journal of Human Ecology
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• v.11 no.2
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• pp.51-61
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• 2010

Using data from the 2007 SCF, this study examined the use of information source for investment decisions of elderly consumers. The results indicated that many elderly consumers (about 88%) involved savings /investment decisions. The elderly used 'Experts' (39.48%) as a major information source for their investment decisions, followed by 'Friends' (24.18%). The results of the multinomial logit analysis suggested that the perceived value, the cost for search, knowledge, risk and some of the demographic factors were significantly related to the choice of the information sources for investments by elderly consumers.

• The Korean Journal of Health Service Management
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• v.5 no.1
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• pp.87-99
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• 2011

The aim of the research is to figure out how the perception and the attitude of hospital staff have effect on cost management behavior, to check the mediation effect in the relationship between cost attitude and cost management behavior, and to provide some basic data of efficient cost management means for hospital staff. The major results of research can be summed up as following. Subordinate factors of cost perception such as conviction, information, and thought were all revealed as meaningful effect ones on cost attitude, but they didn't have meaningful effect on cost management behavior. However, if we check the final results of direct effect, indirect effect, and total effect in its variants, we can understand that cost perception have indirect effect on cost management behavior via cost attitude. Cost attitude was revealed as the greatest variant having direct effect on cost management behavior. As a conclusion, it seems that the correct cost perception can make positive cost attitude, by which desirable cost management behavior can be induced. Therefore, as the correct cost perception can make positive attitude, it is necessary to construct effective system to provide useful cost information for staff at anytime and at any place continually on organization aspect. It is important to get correct cost perception for the positive attitude of staff. Nevertheless, if the positive attitude would not be formed, it is necessary to search for the ways for personal motivation, for the management behavior cannot emerge positively.

• Journal of Information Processing Systems
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• v.15 no.2
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• pp.288-304
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• 2019

The growth of telemedicine-based wireless communication for images-magnetic resonance imaging (MRI) and computed tomography (CT)-leads to the necessity of learning the concept of image compression. Over the years, the transform based and spatial based compression techniques have attracted many types of researches and achieve better results at the cost of high computational complexity. In order to overcome this, the optimization techniques are considered with the existing image compression techniques. However, it fails to preserve the original content of the diagnostic information and cause artifacts at high compression ratio. In this paper, the concept of histogram based multilevel thresholding (HMT) using entropy is appended with the optimization algorithm to compress the medical images effectively. However, the method becomes time consuming during the measurement of the randomness from the image pixel group and not suitable for medical applications. Hence, an attempt has been made in this paper to develop an HMT based image compression by utilizing the opposition based improved harmony search algorithm (OIHSA) as an optimization technique along with the entropy. Further, the enhancement of the significant information present in the medical images are improved by the proper selection of entropy and the number of thresholds chosen to reconstruct the compressed image.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.1
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• pp.32-39
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• 2002

Vector quantization for image compression needs expensive encoding time to find the closest codeword to the input vector. This paper proposes a search algorithm for fast vector quantization encoding. Firstly, we derive a robust condition based on the efficient topological structure of the codebook to dramatically eliminate unnecessary matching operations from the search procedure. Then, we Propose a fast search algorithm using the elimination condition. Simulation results show that with little preprocessing and memory cost, the encoding time of the proposed algorithm is reduced significantly while the encoding quality remains the same with respect to the full search algorithm. It is also found that the Proposed algorithm outperforms the existing search algorithms.