• Journal of electromagnetic engineering and science
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• v.15 no.1
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• pp.14-19
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• 2015

In multicellular wireless networks, intercell interference limits system performance, especially cell edge user performance. One promising approach to solve this problem is the intercell interference coordination (ICIC) scheme. In this paper, we propose a new ICIC scheme based on a resource partitioning approach to enhance cell edge user performance in a wireless multicellular system. The most important feature of the proposed scheme is that the algorithm is performed at each base station in a distributed manner and therefore minimizes the required information exchange between neighboring base stations. The proposed scheme has benefits in a practical environment where the traffic load distribution is not uniform among base stations and the backhaul capacity between the base stations is limited.

• Asia pacific journal of information systems
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• v.16 no.3
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• pp.1-27
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• 2006

In supply chains, collaboration between buyer and supplier can improve firms' ability of supply chains to their objectives and competitive advantages. A key factor in collaboration in supply chain is to identify buyer relationships and supply relationships as antecedents of the factor collaboration. We analyzed data collected from buyers and suppliers sampled from a mobile networks industry in Korea and found that the level of collaboration comes from strong relationships between two parties and the collaboration enhances the supply chain performances. However, buyer relationships and supplier relationships have indirect impacts on trading partners' performance through collaboration whereas both have direct impacts on one's performance. Therefore to enhance supply chain performances, supplier's operational efficiency and buyer satisfaction, firms of buyers and suppliers should consider pursuing practical and substantial collaboration along with buyer-supplier relationships.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.11
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• pp.4595-4610
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• 2020

In the practical communication environment, the accurate channel state information (CSI) is difficult to obtain, which will cause the mismatch of resource and degrade the system performance. In this paper, to account for the channel uncertainties, a robust power allocation scheme for a downlink Non-orthogonal multiple access (NOMA) heterogeneous network (HetNet) is designed to maximize energy efficiency (EE), which can ensure the quality of service (QoS) of users. We conduct the robust optimization model based on worse-case method, in which the channel gains belong to certain ellipsoid sets. To solve the non-convex non-liner optimization, we transform the optimization problem via Dinkelbach method and sequential convex programming, and the power allocation of small cell users (SCUs) is achieved by Lagrange dual approach. Finally, we analysis the convergence performance of proposed scheme. The simulation results demonstrate that the proposed algorithm can improve total EE of SCUs, and has a fast convergence performance.

• Journal of Korean Institute of Industrial Engineers
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• v.14 no.1
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• pp.1-15
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• 1988

DS1 transmission systems use framing bit errors, bipolar violations and code-detected errors to estimate the bit error rate when determining errored and severely errored seconds. Using the coefficient of variation under the memoryless binary symmetric channel assumption, a basic framework to evaluate these estimation schemes is proposed to provide a practical guideline in determining errored and severely errored seconds which are fundamental in monitoring the real-ime error performance of DS1 transmission systems carrying live traffic. To evaluate the performance of the cyclic redundancy check code (CRC), a computer simulation model is used. Several drawbacks of the superframe format in association with real time error performance monitoring are discussed. A few recommendations are suggested in measuring errored and severely errored seconds, and determining service limit alarms through the use of the superframe format. Furthermore, we propose a new robust scheme for determining service limit alarms which take into consideration the limitations of some estimation schemes for the time interval of one second.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.3
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• pp.191-197
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• 1993

In this paper, experimental studies are mainly carried out for the evaluation of precision cutting performance of a machine tool spincle running at high speed with the low load, in consideration of the bending vibration characteristics. As a result a process in presented for the practical application in the machine tools industry to evaluate the cutting performance in design stage of spindles.

• Educational Technology International
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• v.11 no.2
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• pp.105-121
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• 2010

Collaborative learning encourages the use of high-level cognitive strategies, critical thinking, and interpersonal relationships. Despite these advantages, most instructors reveal the difficulties of using project-based collaborative learning; a common problem is the failure of the group to work effectively together. Thus, this study attempted to provide practical advice on group composition with self-regulation. In a college course, 31 groups with 129 students were asked to discuss and prepare the final presentation material and present it together as a collaborative work. All students' self-regulation skills were measured at the beginning of the semester, and the collective self-regulation was computed as an average of the individual scores of each group. The results of regression analysis indicate that the group's collective self-regulation shows a highly significant positive effect on group performance and satisfaction, as self-regulation predicts individual academic performance. The results also show that there is a significant positive relationship between students' self-regulation and participation in group work.

• Educational Technology International
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• v.11 no.2
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• pp.1-24
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• 2010

The study aimed to investigate the differential effects of visual and verbal scaffoldings on web-based problem solving performance. A quasi-experiment with 143 high school students in South Korea was administered. Each student's visualization tendency score was obtained at the beginning of the study. Based on the visualization tendency scores, students were divided into two groups; low and high level visualization tendency groups. Then each group was split in half and randomly assigned to one of the two lessons - one with visual scaffolding and the other with verbal scaffolding. The contents of the two lessons were the same. All students' performance was measured through an essay assignment for a problem solving at the end of the lesson. The result showed that the visual scaffolding group outperformed the verbal scaffolding group (F=22.54, p<.01), regardless of each student's visualization tendency level. The effect size was 0.81, indicating high practical significance. There was no statistically significant interaction effect between scaffolding modalities and students' visualization tendency levels. These findings imply that visual scaffolding is an effective strategy to promote students' problem solving performance.

• Korean Journal of Materials Research
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• v.34 no.2
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• pp.72-78
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• 2024

The lightweight and high strength characteristics of aluminum alloy materials make them have promising prospects in the field of construction engineering. This paper primarily focuses on aluminum alloy materials. Aluminum alloy was combined with concrete, wood and carbon fiber reinforced plastic (CFRP) cloth to create a composite column. The axial compression test was then conducted to understand the mechanical properties of different composite structures. It was found that the pure aluminum tube exhibited poor performance in the axial compression test, with an ultimate load of only 302.56 kN. However, the performance of the various composite columns showed varying degrees of improvement. With the increase of the load, the displacement and strain of each specimen rapidly increased, and after reaching the ultimate load, both load and strain gradually decreased. In comparison, the aluminum alloy-concrete composite column performed better than the aluminum alloy-wood composite column, while the aluminum alloy-wood-CFRP cloth composite column demonstrated superior performance. These results highlight excellent performance potential for aluminum alloy-wood-CFRP composite columns in practical applications.

• Steel and Composite Structures
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• v.51 no.6
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• pp.619-645
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• 2024

In the construction industry, composite structures have revolutionized traditional design principles, opening innovative possibilities. The Concrete Encased - Concrete Filled Steel Tubular (CE-CFST) column stands out as a distinctive composite structure, offering structural stability and resilience for various engineering applications. Comprising Reinforced Concrete (RC) and Concrete Filled Steel Tubular (CFST) components, CE-CFST columns are valued for their inherent properties, including ductility and rigidity, CE-CFST is commonly used in the construction of bridges, high-rise buildings, and more. This article aims to provide a concise overview of the evolutionary development of CE-CFST columns and their performance in structural applications. Through a comprehensive review, the study delves into the behaviour of CE-CFST columns under different scenarios. It examines the influences of key parameters such as size, infills, cross section, failure causes, and design codes on the performance of CE-CFST columns, highlighting their enhanced functionality and future potential. Moreover, the review meticulously examines previous applications of CE-CFST columns, offering insights into their practical implementation.

• Asia pacific journal of information systems
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• v.24 no.1
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• pp.93-112
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• 2014

As personal data breach reared up as a problem domestically and globally, organizations appointing chief privacy officers (CPOs) are increasing. Related Korean laws, 'Personal Data Protection Act' and 'the Act on Promotion of Information and Communication Network Utilization and Information Protection, etc.' require personal data processing organizations to appoint CPOs. Research on the characteristics and role of CPO is called for because of the importance of CPO being emphasized. There are many researches on top management's role and their impact on organizational performance using the Upper Echelon theory. This study investigates what influence the characteristics of CPO gives on the organizational privacy performance. CPO's definition varies depending on industry, organization size, required responsibility and power. This study defines CPO as 'a person who takes responsibility for all the duties on handling the organization's privacy,' This research assumes that CPO characteristics such as role, personality and background knowledge have an influence on the organizational privacy performance. This study applies the part relevant to the upper echelon's characteristics and performance of the executives (CEOs, CIOs etc.) for CPO. First, following Mintzberg and other managerial role classification, information, strategic, and diplomacy roles are defined as the role of CPO. Second, the "Big Five" taxonomy on individual's personality was suggested in 1990. Among these five personalities, extraversion and conscientiousness are drawn as the personality characteristics of CPO. Third, advance study suggests complex knowledge of technology, law and business is necessary for CPO. Technical, legal, and business background knowledge are drawn as the background knowledge of CPO. To test this model empirically, 120 samples of data collected from CPOs of domestic organizations are used. Factor analysis is carried out and convergent validity and discriminant validity were verified using SPSS and Smart PLS, and the causal relationships between the CPO's role, personality, background knowledge and the organizational privacy performance are analyzed as well. The result of the analysis shows that CPO's diplomacy role and strategic role have significant impacts on organizational privacy performance. This reveals that CPO's active communication with other organizations is needed. Differentiated privacy policy or strategy of organizations is also important. Legal background knowledge and technical background knowledge were also found to be significant determinants to organizational privacy performance. In addition, CPOs conscientiousness has a positive impact on organizational privacy performance. The practical implication of this study is as follows: First, the research can be a yardstick for judgment when companies select CPOs and vest authority in them. Second, not only companies but also CPOs can judge what ability they should concentrate on for development of their career relevant to their job through results of this research. Cultural social value, citizen's consensus on the right to privacy, expected CPO's role will change in process of time. In future study, long-term time-series analysis based research can reveal these changes and can also offer practical implications for government and private organization's policy making on information privacy.