• Journal of Intelligence and Information Systems
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• v.10 no.1
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• pp.13-25
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• 2004

In the online shopping environment, consumers suffer from the process of selecting an optimal supplier. Although comparison shopping agent-based web sites and consumers' online community sites support the selection process, they have limitations when considering diverse and dynamic purchase conditions as a whole, which is the cause of additional consumer effort for optimal supplier selection. This study provides a decision support model with a sensitivity analysis for selecting an optimal supplier considering purchase conditions as a whole. It screens suppliers with filtering factors and provides optimal suppliers through a sensitivity analysis from a Quadratic Programming model. We implemented a prototype system and showed that it could be an effective decision support system for selecting the optimal supplier in the online shopping environment.

• The Journal of Korean Association of Computer Education
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• v.22 no.3
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• pp.55-65
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• 2019

In programming language learning system of flip learning methods, the evaluation of cyber lectures generally proceeds from online to multiple choice questions. In this case, the questions are randomly extracted from the question bank and given to individual learners. In order for these evaluation results to be reflected in the grades, the equity of the examination question is more important than anything else. Especially in the programming language subject, the degree of difficulty that learners think can be different depending on the type of problem. In this paper, we classify the types of multiple-choice problems into two categories, and manage the difficulty level by each type. And we propose a question selection algorithm that considers both difficulty level and type of question. Considering the characteristics of the programming language, experimental results show that the proposed algorithm is more efficient and fair than the conventional method.

• The Journal of Society for e-Business Studies
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• v.21 no.2
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• pp.151-161
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• 2016

In the era of the Web 2.0, characterized by the openness, sharing and participation, it is easy for internet users to produce and share the data. The amount of the unstructured data which occupies most of the digital world's data has increased exponentially. One of the kinds of the unstructured data called personal online product reviews is necessary for both the company that produces those products and the potential customers who are interested in those products. In order to extract useful information from lots of scattered review data, the process of collecting data, storing, preprocessing, analyzing, and drawing a conclusion is needed. Therefore we introduce the text-mining methodology for applying the natural language process technology to the text format data like product review in order to carry out extracting structured data by using R programming. Also, we introduce the data-mining to derive the purpose-specific customized information from the structured review information drawn by the text-mining.

• Convergence Security Journal
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• v.19 no.4
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• pp.43-53
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• 2019

Recently, a number of military intranet infiltrations suspected of North Korea have been discovered. There was a problem that a vulnerability could occur due to the modification of user authentication data that can access existing military information systems. In this paper, we applied mutual verification technique and API (Application Programming Interface) forgery / forgery blocking and obfuscation to solve the authentication weakness in web browsers that comply with FIDO (Fast IDentity Online) standard. In addition, user convenience is improved by implementing No-Plugin that does not require separate program installation. Performance tests show that most browsers perform about 0.1ms based on the RSA key generation rate. In addition, it proved that it can be used for commercialization by showing performance of less than 0.1 second even in the digital signature verification speed of the server. The service is expected to be useful for improving military information system security as an alternative to browser authentication by building a web secure storage.

• Journal of Korea Society of Industrial Information Systems
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• v.27 no.2
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• pp.11-24
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• 2022

For the questions asked for LMS-based online evaluation the professor directly set exam questions, or use the automatic question-taking method according to the level of difficulty using the question bank divided by category. Among them, it is important to manage the difficulty of questions in an objective and efficient way, above all, in the automatic question-taking method according to difficulty. Because the questions presented to the evaluators may be different. In this paper, we propose an difficulty re-adjustment algorithm that considers not only the correct rate of a problem but also the time taken to solve the problem. For this, a logistic regression classification algorithm was used of machine learning, and a reference threshold was set based on the predicted probability value of the learning model and used to readjust the difficulty of each item. As a result, it was confirmed that there were many changes in the difficulty of each item that depended only on the existing correct rate. Also, as a result of performing group evaluation using the adjustment difficulty problem, it was confirmed that the average score improved in most groups compared to the difficulty problem based on the percentage of correct answers.

• Journal of Industrial Convergence
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• v.20 no.2
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• pp.45-50
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• 2022

In this study, an e-portfolio system was constructed and utilized to communicate with students, while processing the overall procedure of teaching-learning activities as data for qualitative improvement in the non-face-to-face educational environment. The e-portfolio system was designed to support the entire process of reflection from the instructor's lesson planning, regular checking of the learner's understanding during the course operation process, online communication, and support for learner-centered educational activities. Analyzing the effectiveness of the communication-based learning effect between instructors and learners using the e-portfolio in liberal arts programming classes, which may be difficult for non-major students, a significant correlation was found in problem-solving skills, and midterm and final exams. Additionally, the result of analyzing the expanded applicability of e-portfolio satisfaction demonstrated a significant correlation with the students' computational thinking ability, test results, assignments, and academic performance. It was found to have a significant effect on the improvement of computational thinking ability. If non-face-to-face education is conducted using the proposed e-portfolio system type, it will be possible to improve the quality of online education, while communicating effectively with students.

• KIPS Transactions on Software and Data Engineering
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• v.8 no.8
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• pp.317-322
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• 2019

Programming judge systems for programming training support are typically built on the Web, where the examiners uploads a programming problem, which the student reads and submits an answer to the problem. The judge system executes the submitted answer of source code to provide feedback such as pass, failure, and error messages. Students who receive the feedback except for the pass continues debugging the source code until they are judged to pass. We developed an online judge system to support programming training and analyzed answers submitted by the students and found that many of the students who were not judged to pass that test did not know exactly where they were wrong but continued to solve the problem. The current judge system generally feeds runtime error messages back to students. However, with only runtime error message, it is difficult for student who train to find the wrong part of the answer. Therefore, in this paper, we propose a system that provides the feedback of programming failure by analyzing the control flow of the test cases used in the source code submitted by the student. The proposed system helps students find the wrong parts more quickly by feeding back the paths where faults in the control flow may exist. In addition, we show that this system is applicable to the answer source code that the actual student submitted.

• Journal of Korean Library and Information Science Society
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• v.22
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• pp.61-93
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• 1995

This paper discussed which of the three basic entries of serials that changed their titles-earliest, latest, or successive entry cataloging-is the most efficient, informative, and economical in a manual and an online environment. The results of the study are as follow: 1. Earliest entry cataloging or as an alternative, successive entry cataloging advocated by Cutter in 1976 was replaced in ALA Cataloging Rules by latest entry cataloging and with AACR1 and AACR2, latest entry cataloging was replaced by successive entry cataloging again. 2. Entry method of serial cataloging should be determined in consideration of goals of catalog, efficiency of catalog retrieval, theoretical and practical standpoint of entry methods, average cataloging time and cost, the state of adaption. 3. In a card catalog environment, if the numbering and class number of the serial that title proper changed into initials itself continue and the title history must not be too complicated, the serial is desirable to entry under the latest title. Except for above case, successive entry cataloging enables serials to be more quickly and economically made available to users than with either earliest or latest entry cataloging. 4. In an automated catalog environment, successive entry cataloging has more potential of satisfying and impairs the efficiency of both accessing and processing a library's serials collection. However, when initial cataloging by MARC format is done, careful screen design and complex programming will be needed. And subfield containing the local record number should be added to the programming means to link the various records together, i.e., 780 (preceding title) and 785 (succeeding title) fields for all related titles.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.10
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• pp.4640-4661
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• 2018

To cope with the explosive growth of Internet services, Service Function Chaining (SFC) based on Software-defined Networking (SDN) is an emerging and promising technology that has been suggested to meet this challenge. Determining the placement of Virtual Network Functions (VNFs) and routing paths that optimize the network utilization and resource consumption is a challenging problem, particularly without violating service level agreements (SLAs). This problem is called the optimal SFC placement problem and an Integer Linear Programming (ILP) formulation is provided. A greedy heuristic solution is also provided based on an improved two-step mapping algorithm. The obtained experimental results show that the proposed algorithm can automatically place VNFs at the optimal locations and find the optimal routing paths for each online request. This algorithm can increase the average request acceptance rate by about 17.6% and provide more than 20-fold reduction of the computational complexity compared to the Greedy algorithm. The feasibility of this approach is demonstrated via NetFPGA-10G prototype implementation.

• The Journal of Industrial Distribution & Business
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• v.9 no.5
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• pp.25-35
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• 2018

Purpose - The purpose of this paper is to partition a last-mile delivery network into zones and to determine locations of last mile delivery centers (LMDCs) in Bangkok, Thailand. Research design, data, and methodology - As online shopping has become popular, parcel companies need to improve their delivery services as fast as possible. A network partition has been applied to evaluate suitable service areas by using METIS algorithm to solve this scenario and a facility location problem is used to address LMDC in a partitioned area. Research design, data, and methodology - Clustering and mixed integer programming algorithms are applied to partition the network and to locate facilities in the network. Results - Network partition improves last mile delivery service. METIS algorithm divided the area into 25 partitions by minimizing the inter-network links. To serve short-haul deliveries, this paper located 96 LMDCs in compact partitioning to satisfy customer demands. Conclusions -The computational results from the case study showed that the proposed two-phase algorithm with network partitioning and facility location can efficiently design a last-mile delivery network. It improves parcel delivery services when sending parcels to customers and reduces the overall delivery time. It is expected that the proposed two-phase approach can help parcel delivery companies minimize investment while providing faster delivery services.