• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.2
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• pp.66-77
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• 2021

Companies widely use survey to identify customer requirements, but the survey has some problems. First of all, the response is passive due to pre-designed questionnaire by companies which are the surveyor. Second, the surveyor needs to have good preliminary knowledge to improve the quality of the survey. On the other hand, text mining is an excellent way to compensate for the limitations of surveys. Recently, the importance of online review is steadily grown, and the enormous amount of text data has increased as Internet usage higher. Also, a technique to extract high-quality information from text data called Text Mining is improving. However, previous studies tend to focus on improving the accuracy of individual analytics techniques. This study proposes the methodology by combining several text mining techniques and has mainly three contributions. Firstly, able to extract information from text data without a preliminary design of the surveyor. Secondly, no need for prior knowledge to extract information. Lastly, this method provides quantitative sentiment score that can be used in decision-making.

• Journal of the Korean Society for information Management
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• v.40 no.4
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• pp.279-306
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• 2023

This study analyzed bibliographic attributes related to the selection and use of reading materials based on data on books borrowed or purchased together in order to understand the properties of reading materials that have complex user needs from various perspectives. As a result of creating co-occurrence matrices of bibliographic attribute terms by dividing them into 26 sub-attribute units related to KDC main class, target reader, and user age, and performing network analyses, the details and prominent mediating role of bibliographic attributes of reading materials were identified. The results of this study will be helpful in designing facets of reading information systems, including library OPAC, in the future.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.6
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• pp.1319-1326
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• 2015

The symmetric key encryption algorithms, such as the AES or the ARIA, generate round keys by the key expansion mechanism. While the algorithm is executed, key expansion mechanism emits information about the secret key by the power consumption. The vulnerability exists that can reduce significantly the candidate of the secret key by the simple power analysis attack using a small number of the power traces. Therefore, we'll have to study about the attack and the countermeasure to prevent information leakage. While a simple power analysis attack on the AES key expansion has been studied since 2002, ARIA is insufficient. This paper presents a simple power analysis attack on 8-bit implementations of the ARIA-128 key expansion. The presented attack efficiently utilizes this information leakage to substantially reduce the key space that needs to be considered in a brute-force search for the secret key. We show that ARIA is vulnerable to a SPA attack based on hamming weight leakage.

• Korean Journal of Computational Design and Engineering
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• v.20 no.1
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• pp.65-74
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• 2015

Structure and/or fluid analysis is gradually increased by an essential design process in the small and medium-sized businesses (SMBs) because of the needs for a rapid design process and the certification about the supplement of the parts by the large business (LB). In this paper, we developed the web-based ezSIM platform installed in the resources integrated system server. The ezSIM platform is based on the heterogeneous linux and windows operating system for the user-friendly connection with the part of the analysis for the SMBs. The procedure of the structure/fluid analysis service module using the public software and the license-free open code in the ezSIM platform was explained. The convenience of the ezSIM platform service was presented by the reaction rate of the graphic motion compared with that of a local PC and the solving and pre-post processing interface compared with that of the KISTI supercomputer. The web-based ezSIM platform service was identified as a useful and essential platform to the SMBs for the usage of the structure and/or fluid analysis procedure.

• Journal of the Korea Convergence Society
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• v.13 no.3
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• pp.203-216
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• 2022

In the recent business environment, purchase patterns are changing around the influence of COVID-19 and the online market. This study analyzed cluster and correlation analysis based on purchase and product information. The cluster analysis of new methods was attempted by creating customer, product, and cross-bonding clusters. The cross-bonding cluster analysis was performed based on the results of each cluster analysis. As a result of the correlation analysis, it was analyzed that more association rules were derived from a cross-bonding cluster, and the overlap rate was less. The cross-bonding cluster was found to be highly efficient. The cross-bonding cluster is the most suitable model for recommending products according to customer needs. The cross-bonding cluster model can save time and provide useful information to consumers. It is expected to bring positive effects such as increasing sales for the company.

• Journal of Microbiology
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• v.41 no.3
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• pp.232-238
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• 2003

Previous phylogenetic studies on human immunodeficiency virus type 1 (HIV-1) isolated from Korean patients suggest that the major subtype of Korean isolate is subtype B. In this subtype, some of the Korean isolates seem to be clustered exclusively of foreign isolates. Presence of this so-called “Korean clade” among Korean isolates is unique but needs verification since the number of Korean isolates used in previous studies was limited. This study aimed to identify the presence of the “Korean clade” by molecular phylogenetic analysis using all the Korean nef gene sequences registered in the NCBI GenBank (N=243) together with 32 reference strains and 77 foreign isolates. Extensive analysis of the nef gene nucleotide sequences by neighbor-joining method revealed the following. Most (83.1 ％) of the Korean isolates belonged to subtype B, and 81.2％ of subtype B were clustered together and excluded foreign isolates (bootstrap value=91.9％ ). Within Korean subtype B cluster, no characteristic subcluster formation was evident since the bootstrap values for the subcluster were very low. Due to limited information, the phylogenetic analysis failed to identify the epidemiological linkage among specific groups such as homosexuals and hemophiliacs within the Korean subtype B cluster. Detailed analysis and epidemiological information are needed to clarify the origin and significance of the Korean subtype B cluster.

• Journal of Korean Institute of Industrial Engineers
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• v.42 no.2
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• pp.129-137
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• 2016

A colonoscopy is important because it detects the presence of polyps in the colon that can lead to colon cancer. How often one needs to repeat a colonoscopy may depend on various factors. The main purpose of this study is to determine personalized surveillance interval of colonoscopy based on characteristics of patients including their clinical information. The clustering analysis using a partitioning around medoids algorithm was conducted on 625 patients who had a medical examination at Korea University Anam Hospital and found several subgroups of patients. For each cluster, we then performed survival analysis that provides the probability of having polyps according to the number of days until next visit. The results of survival analysis indicated that different survival distributions exist among different patients' groups. We believe that the procedure proposed in this study can provide the patients with personalized medical information about how often they need to repeat a colonoscopy.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.12
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• pp.4706-4724
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• 2020

With various structured data, such as the company size, loan balance, and savings accounts, the voice of customer (VOC), which is text data containing contact history and counseling details was analyzed in this study. To analyze unstructured data, the term frequency-inverse document frequency (TF-IDF) analysis, semantic network analysis, sentiment analysis, and a convolutional neural network (CNN) were implemented. A performance comparison of the models revealed that the predictive model using the CNN provided the best performance with regard to predictive power, followed by the model using the TF-IDF, and then the model using semantic network analysis. In particular, a character-level CNN and a word-level CNN were developed separately, and the character-level CNN exhibited better performance, according to an analysis for the Korean language. Moreover, a systematic selection model for optimal text mining techniques was proposed, suggesting which analytical technique is appropriate for analyzing text data depending on the context. This study also provides evidence that the results of previous studies, indicating that individual customers leave when their loyalty and switching cost are low, are also applicable to corporate customers and suggests that VOC data indicating customers' needs are very effective for predicting their behavior.

• The Korean Journal of Food And Nutrition
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• v.34 no.6
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• pp.650-661
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• 2021

The purpose of this study was to compare and analyze the importance and satisfaction of consumer selective attributes by home meal replacement (HMR) types using local ingredients. This study was conducted from December 4 to December 8, 2020. A total of 380 responses organized according to preferred types of HMR (100 for Ready to Eat (RTE), 92 for Ready to Heat (RTH), 88 for Ready to Cook (RTC), 100 for Ready to Prepared (RTP) were used for the final analysis. Statistical analysis was conducted by descriptive analysis, paired t-test, and importance-satisfaction analysis by HMR type. Findings of this study showed significant differences in consumer selective attributes by HMR type. RTE and RTC need to improve quality while RTH needs to improve quality and packaging. Notable selective attributes were quality, packaging, and information. They were located in different quadrants of each HMR type. All other attributes appeared in the same quadrant. Further research is needed to determine differences in quality, packaging, and information for each HMR type. Results of this study provide basic data for developing products and marketing strategies for each type of HMR products using local ingredients.

• Journal of Information Science Theory and Practice
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• v.4 no.3
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• pp.28-42
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• 2016

Smartphones have become one of the most prevalent information devices in the current information environment. Although many people use smartphones for communication and information acquisition, these two functions are closely related and cannot be separated. However, many studies have focused on identifying each function of a smartphone independently. There are few studies that investigate the relationships between communication and information acquisition functions on smartphones. This research empirically analyzed and identified the relationships between these two functions of smartphones by conducting a survey. The results of the analysis showed that the activities for information acquisition make differences in communication on a smartphone. People who want to acquire more information tend to use a smartphone for communication purposes. Besides, communication activities on a smartphone also affect the acquisition of information. In addition, communication activities on a smartphone also affect the establishment of interpersonal relationships that lead to the acquisition of more information. From these results, it is identified that communication activities and information acquisition are interrelated when satisfying the information needs of smartphone users. Especially, communication activities on a smartphone positively affect people's information activities and enhance information acquisition.