• Journal of Internet Computing and Services
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• v.16 no.6
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• pp.89-95
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• 2015

Traditional frequent pattern mining discovers valid patterns with no smaller frequency than a user-defined minimum threshold from databases. In this framework, an enormous number of patterns may be extracted by a too low threshold, which makes result analysis difficult, and a too high one may generate no valid pattern. Setting an appropriate threshold is not an easy task since it requires the prior knowledge for its domain. Therefore, a pattern mining approach that is not based on the domain knowledge became needed due to inability of the framework to predict and control mining results precisely according to the given threshold. Top-k frequent pattern mining was proposed to solve the problem, and it mines top-k important patterns without any threshold setting. Through this method, users can find patterns from ones with the highest frequency to ones with the k-th highest frequency regardless of databases. In this paper, we provide knowledge both on frequent and top-k pattern mining. Although top-k frequent pattern mining extracts top-k significant patterns without the setting, it cannot consider both item quantities in transactions and relative importance of items in databases, and this is why the method cannot meet requirements of many real-world applications. That is, patterns with low frequency can be meaningful, and vice versa, in the applications. High utility pattern mining was proposed to reflect the characteristics of non-binary databases and requires a minimum threshold. Recently, top-k high utility pattern mining has been developed, through which users can mine the desired number of high utility patterns without the prior knowledge. In this paper, we analyze two algorithms related to top-k high utility pattern mining in detail. We also conduct various experiments for the algorithms on real datasets and study improvement point and development direction of top-k high utility pattern mining through performance analysis with respect to the experimental results.

• Journal of Digital Convergence
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• v.20 no.5
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• pp.513-523
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• 2022

Generally, people act to use Information Technology on the premise of their experience in using various Information Technology. Namely, users perceive Information Technology through their User Experience, and these User Experiences can be said to impact Continuous Use Intention of the Information Technology. Based on this condition, the present study was proceeded to investigate the User Satisfaction's Mediating effect in the relationship between User Experience and Continuous Use Intention of the OTT services. For this purpose, 195 male and female college students' survey data were used for analysis, verified through the SPSS Process Macro. As a result of the analysis, not only the Reliability experience for the OTT services but also the Usability, Convenience, and Pleasurable experiences' User Experiences were verified that Use Satisfaction was Fully Mediating in relation to Continuous Use Intention. This result gives an implication that the importance of User Experience and Use Satisfaction in maintaining customers through continuous use of OTT services are worth noting. Overall, the present study increased the customer utility for OTT services and confirmed the importance of User Experience and Use Satisfaction in order to increase the competitiveness of the company. Also, it proposed a direction for an in-depth future research to develop this study.

• The Research Journal of the Costume Culture
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• v.28 no.4
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• pp.420-428
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• 2020

This study analyzed the expression of hanbok in online fashion styling games, and examined the main themes of and user reactions to hanbok fashion styling games through semantic network analysis and sentiment analysis. KrKwic, Textom, and NodeXL were used for data collection and analysis. The findings of the study are as follows: First, depending on the designer's expressive method, hanbok fashion styling games provide typical traditional hanbok, modern hanbok, and dress-like fusion hanbok, demonstrating contents with various themes for different sexes, classes, and situations. Second, as a result of analyzing the themes of hanbok-related styling game contents, it turned out that the main themes are tradition, color, historical drama, fusion hanbok, holiday, and love. Most of them produce modernized hanbok that reflect the situation and utility rather than strictly traditional ones. Third, as a result of analyzing user reviews of hanbok styling game contents, positive factors mostly turned out to be the satisfaction of the hanbok contents, with the users also showing positive intent to wear hanbok. Through this, it was found out that hanboks portrayed in game contents could potentially cause the user's positive intent to wear hanbok. Negative factors turned out to be the discordance between the intrinsic image of hanbok and the game character's image.

• Journal of the Ergonomics Society of Korea
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• v.29 no.5
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• pp.797-810
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• 2010

This study examined perceived discomforts encountered in residential facilities such as individual houses and apartments, and suggested a procedure for improving the problems in the living residence. The participants consisted of two groups of people: normal and underprivileged people; the underprivileged group was classified into 3 sub-groups: elderly people (over 65 years old), handicapped people and pregnant women. To identify inconvenient places and design factors in the residential housing, a total of 200 subjects (50 for each group) participated in the survey using the 7-point Likert scale. As a result, all the user groups mainly answered a high degree of discomfort due to narrow parking places, doorsills, and height differences between floors. The elderly, the handicapped, and the pregnant women replied that it is uncomfortable to use ramps and utility rooms. In a follow-up study, one-to-one in-depth interviews were conducted with some of the participants to analyze the detailed causes of inconvenient places and design factors. This study also suggested the procedure for solving the problems in various design factors from perspective of universal design, by considering prior studies which focused on a certain user group like the elderly. This procedure was suggested to consider as many user groups as possible at the same time. The results can be used to understand the discomforts of various user groups on residential housing. The procedure can also be used to develop universal design guidelines for the living residence.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.5
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• pp.1569-1586
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• 2015

This paper considers the optimal cell association and resource allocation for load balancing in a heterogeneous cellular network subject to user's quality-of-service (QoS) constraints. We adopt the proportional fairness (PF) utility maximization formulation which also accommodates the QoS constraints in terms of minimum rate requirements. With equal resource allocation this joint optimization problem is either infeasible or requires relaxation that yields a solution which is difficult to implement. Nevertheless, we show that this joint optimization problem can be effectively solved without any priori assumption on resource allocation and yields a cell association scheme which enforces single BS association for each user. We re-formulated the joint optimization problem as a network-wide resource allocation problem with cardinality constraints. A reweighted heuristic l₁-norm regularization method is used to obtain a sparse solution to the re-formulated problem. The cell association scheme is then derived from the sparsity pattern of the solution, which guarantees a single BS association for each user. Compared with the previously proposed method based on equal resource allocation, the proposed framework results in a feasible cell association scheme and yields a robust solution on resource allocation that satisfies the QoS constraints. Our simulations illustrate the impact of user's minimum rate requirements on cell association and demonstrate that the proposed approach achieves load balancing and enforces single BS association for users.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.10
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• pp.4661-4680
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• 2016

Cognitive radio (CR) technology is an effective solution to the spectrum scarcity issue. Collaborative spectrum sensing is known as a promising technique to improve the performance of spectrum sensing in cognitive radio networks (CRNs). However, collaborative spectrum sensing is vulnerable to spectrum data falsification (SSDF) attack, where malicious users (MUs) may send false sensing data to mislead other secondary users (SUs) to make an incorrect decision about primary user (PUs) activity, which is one of the key adversaries to the performance of CRNs. In this paper, we propose a coalition based malicious users detection (CMD) algorithm to detect the malicious user in CRNs. The proposed CMD algorithm can efficiently detect MUs base on the Geary'C theory and be modeled as a coalition formation game. Specifically, SSDF attack is one of the key issues to affect the resource allocation process. Focusing on the security issues, in this paper, we analyze the power allocation problem with MUs, and propose MUs detection based power allocation (MPA) algorithm. The MPA algorithm is divided into two steps: the MUs detection step and the optimal power allocation step. Firstly, in the MUs detection step, by the CMD algorithm we can obtain the MUs detection probability and the energy consumption of MUs detection. Secondly, in the optimal power allocation step, we use the Lagrange dual decomposition method to obtain the optimal transmission power of each SU and achieve the maximum utility of the whole CRN. Numerical simulation results show that the proposed CMD and MPA scheme can achieve a considerable performance improvement in MUs detection and power allocation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.2
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• pp.538-561
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• 2020

Recommender Systems (RecSys) have a major role in e-commerce for recommending products, which they may like for every user and thus improve their business aspects. Although many types of RecSyss are there in the research field, the state of the art RecSys has focused on finding the user similarity based on sequence (e.g. purchase history, movie-watching history) analyzing and prediction techniques like Recurrent Neural Network in Deep learning. That is RecSys has considered as a sequence prediction problem. However, evaluation of similarities among the customers is challenging while considering temporal aspects, context and multi-component ratings of the item-records in the customer sequences. For addressing this issue, we are proposing a Deep Learning based model which learns customer similarity directly from the sequence to sequence similarity as well as item to item similarity by considering all features of the item, contexts, and rating components using Dynamic Temporal Warping(DTW) distance measure for dynamic temporal matching and 2D-GRU (Two Dimensional-Gated Recurrent Unit) architecture. This will overcome the limitation of non-linearity in the time dimension while measuring the similarity, and the find patterns more accurately and speedily from temporal and spatial contexts. Experiment on the real world movie data set LDOS-CoMoDa demonstrates the efficacy and promising utility of the proposed personalized RecSys architecture.

• The KIPS Transactions:PartC
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• v.8C no.5
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• pp.557-564
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• 2001

Many people use Linux and FreeBSD because it is freeware and excellent performance. The open source code is very important feature but it also has some problem which may be attacked by hackers frequently. This paper describes the SecuROS of secure operating system that is best solution to this problem and introduces user and programmer interface for active use of secure operating system. Developed secure operating system is composed of the access control method MAC and ACL and conforms to the POSIX which is universally used.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.7
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• pp.2530-2547
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• 2015

In the recent years, femtocell technology has received a considerable attention due to the ability to provide an efficient indoor wireless coverage as well as enhanced capacity. However, under the spectrum sharing between femtocell user equipment (FUEs) and the owner of spectrum macrocell user equipment (MUEs), both may experience higher uplink interference to each other. This paper proposes a novel distributed power control algorithm for the interference management in two-tier femtocell networks. Due to the assignment of licensed radio frequency to the outdoor macrocell users, the access priority of MUEs should be higher than FUEs. In addition, the quality of service (QoS) of MUEs that is expressed in the target signal-to-interference-plus-noise ratio (SINR) must always be achieved. On the other hand, we consider an efficient QoS provisioning cost function for the low-tier FUEs. The proposed algorithm requires only local information and converges even in cases where the frontiers of available power serve the target SINRs impossible. The advantage of the algorithm is the ability to implement in a distributed manner. Simulation results show that the proposed algorithm based on our cost function provides effective resource allocation and substantial power saving as compared to the traditional algorithms.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2001.10a
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• pp.11-28
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• 2001

The Korean functional Genomics Project focuses on stomach and liver cancers. Specimens collected by six hospital teams are used in BNA microarray experiments. Experimental conditions, spot measurement data, and the associated clinical information are stored in a relational database. Microarray database schema was developed based on EBI's ArrayExpress. A diagrammatic representation of the schema is used to help navigate over marty tables in the database. Field description, table-to-table relationship, and other database features are also stored in the database and these are used by a PERL interface program to generate web-based input forms on the fly. As such, it is rather simple to modify the database definition and implement controlled vocabularies. This PERL program is a general-purpose utility which can be used for inputting and updating data in relational databases. It supports file upload and user-supplied filters of uploaded data. Joining related tables is implemented using JavaScripts, allowing this step to be deferred to a later stage. This feature alleviates the pain of inputting data into a multi-table database and promotes collaborative data input among several teams. Pathological finding, clinical laboratory parameters, demographical information, and environmental factors are also collected and stored in a separate database. The same PERL program facilitated developing this database and its user-interface.