• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.1
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• pp.179-187
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• 2014

The underlay protocol is a cognitive radio method in which secondary or cognitive users use the same frequency without affecting the quality of service (QoS) for the primary users. In addition, because of the broadcast characteristics of the wireless environment, some nodes, which are called eavesdropper nodes, want to illegally receive information that is intended for other communication links. Hence, Physical Layer Security is applied considering the achievable secrecy rate (ASR) to prevent this from happening. In this paper, a performance analysis of the amplify-and-forward scheme under an interference constraint and Physical Layer Security is investigated in the cooperative communication mode. In this model, the relays use an amplify-and- forward method to help transmit signals from a source to a destination. The best relay is chosen using an opportunistic relay selection method, which is based on the end-to-end ASR. The system performance is evaluated in terms of the outage probability of the ASR. The lower and upper bounds of this probability, based on the global statistical channel state information (CSI), are derived in closed form. Our simulation results show that the system performance improves when the distances from the relays to the eavesdropper are larger than the distances from the relays to the destination, and the cognitive network is far enough from the primary user.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.4
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• pp.296-301
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• 2017

In various industrial places such as power generation plants, petrochemical and unit factories, the demands of systems that produce hot water by utilizing wasted or surplus steam have been increased. Compact steam unit(CSU) is a system that can meet these demands and produce hot water by using surplus or wasted steam, and it is also one of the good solutions in view of energy reuse. The new CSU with a capacity of 1,600 kW was developed with a hybrid plate heat exchanger of which thermal performances are better than a conventional plate heat exchanger, an improved temperature control valve, a user-friendly control system, and other components in this study. The purpose of this study was to obtain performance data of the new CSU through various experiments and utilize them for the CSU commercialization. The experimental results show that heat balances between the hot side(steam) and the cold side(cold water) were within ${\pm}0.77%$, and the fluctuations of outlet temperature of the secondary side which are one of the most important evaluation factors in the CSU were $(0{\sim}0.3)^{\circ}C$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.745-755
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• 2017

University campuses try to satisfy students' demands. Therefore, the physical environment of university campuses keeps changing. Due to the increasing the number of students and shortage of school building facilities, it is necessary to improve the facilities and create new space in the campus, in order to solve this problem and improve the universities. At the moment, the learning method of university students is evolving toward discussion sessions involving fellow students and presentations utilizing multimedia facilities. In response to these changes, a new type of independent space has appeared, which is called the Group Study Room. In this study, we analyze the spatial characteristics of the Group Study Room. Also, through an IPA(Importance Performance Analysis), this study tries to examine the relationship between the spatial characteristics and users' satisfaction. This analysis is expected to reveal the importance of the spatial characteristics of the group study rooms from the users' point of view. This research can be used for facility planning in universities in the future. The primary aim of this study is to analyze the physical environment of the Group Study Rooms of K university. The secondary aim of this study is to manifest the characteristics of these new learning spaces and to check the space elements of the group study rooms for the sake of efficient planning and management.

• Journal of The Korean Association For Science Education
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• v.38 no.5
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• pp.649-665
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• 2018

In this study, we extracted the core competencies of makers through the analysis of critical incident technique and behavioral event interview to explore the nature and attributes of maker education, and then we developed a maker competency model based on these core competencies. As a result, six competency groups and 23 sub-competencies were extracted. In other words, we were able to confirm the existence of integrated thinking competency group consisting of four competencies made up of 'analytic thinking', 'intuitive thinking', 'visual thinking', and 'empirical thinking' and that of collaborative competency group with four competencies of 'sharing', 'communication', 'conflict management', and 'scrupulosity'. In addition, we could also confirm the existence of making mind competency group, which is composed of four competencies namely 'interest in various areas', 'challenge consciousness', 'failure management', and 'pleasure of the making process'. We could also confirm that human-centered competence group consisting of two competencies of 'humanity' and 'user-oriented' and the problem-finding competence group consisting of two competencies of 'observation' and 'recognition of discomfort in daily life'. Lastly, the making practice competency group is composed of seven competencies: 'understanding making tool', 'understanding electricity', 'understanding programming', 'planning', 'hand knowledge', 'information search', and 'direct execution'. We discussed educational implications of these findings.

• Journal of Digital Convergence
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• v.15 no.7
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• pp.259-269
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• 2017

This study analyzed medical aid case management effects based on the number of access by visits, phone calls, letters, internal investigation, resource links, and requests, in medical aid case management business that is carried out to improve the quality of life of medical care beneficiaries and reduce financial cost. Secondary analysis study using data of 564 high-risk group in the medical aid case management and their healthcare utilization data. Letters had positive correlations with the scores of all case management domains. The higher visits was, the lower the score of self-health care ability was, and the higher the number of phone calls was, the higher the score for reasonable medical use was. While there was no significant difference in medical cost according to aid management by interventions, the higher visits and resource links were, the lower the subjects' total number of payment days was. There is a difference in the various areas of the quality of health -related life and medical use depending on case management by intervention method and its number. It is necessary to carry out the efficient number of access to case management by intervention method.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.7
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• pp.927-935
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• 2019

Screw-failure accidents in small ships frequently occur in coastal waters. In particular, vessels' propulsion systems are frequently coiled due to objects such as fish-nets and ropes that float on the sea. The failure of the ship's propulsion system can cause primary accidents such as ship operation delays and drifting due to loss of power; furthermore, the possibility of secondary accidents such as those involving operators in the underwater removal of rope stuck in a propeller. Ships that do not have the proper tools to solve these problems must be either lifted onto land to be repaired or divers must dive directly under the ship to solve the problem. Accordingly, some small vessels have been equipped with rope-cutter devices on the propeller shaft to prevent ship propeller system accidents in recent years; however, they are not being applied efficiently due to the cost and time of installation. To solve these problems, this study develops an underwater rope-cutter device and controller for the removal of propeller and shaft foreign material in small vessels. This device has simple structures that use the principle of a saw. Meteor gears and crank pins were used for the straight-line rotation of saw blades of the underwater rope-cutters to allow for long strokes. Furthermore, the underwater rope-cutting machines can be operated by being connected to the ship battery. The user, a non-professional, can ensure convenience and stability by applying reverse current prevention and a speed control circuit so that it can be used more conveniently and safely.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.7
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• pp.1546-1553
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• 2015

In cognitive radio technology, the overall capacity of communications systems can be improved without allocating additional bands by allowing secondary system to utilize the band when a primary system who has right to use the band does not utilize it. Therefore, spectrum sensing to determine the existence of primary system is utmost important in the cognitive radio technology. In this work, we consider a novel cooperative spectrum sensing in cognitive cellular systems. Especially, we consider the case in which heterogeneous primary systems coexist, i.e., heterogenous transmission power and sensing requirement of primary system, such that only portion of users in cognitive cellular systems are able to detect the primary system. In this case, we propose new cooperative spectrum sensing with multiple sensing stages to properly detect the existence of primary systems in this kind of situations. Moreover, we analyze the performance of conventional cooperative spectrum sensing schemes such as OR-rule, AND-rule and MAJORITY-rule under the existence of heterogeneous primary systems. Finally, we investigate the performance of the proposed scheme through computer based simulations and show that the existence of primary systems can be determined accurately by using our proposed scheme.

• Journal of Plant Biotechnology
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• v.45 no.4
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• pp.289-298
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• 2018

The Biosafety Division of the National Academy of Agricultural Science has developed a 'Crop Composition DB' that provides analytical data on commercialized crops. It can be used as a reference in the 'Comparative Evaluation by Compositional Analysis' for the safety assessment of genetically modified (GM) crops. This database provides the composition of crops cultivated in Korea, and thus upgrades the data to check the extent of changes in the compositional content depending on the cultivated area, varieties and year. The database is a compilation of data on the antioxidant, nutrient and secondary metabolite compositions of rice and capsicum grown in two or more cultivation areas for a period of more than two years. Data analysis was conducted under the guidelines of the Association of Official Analytical Chemists or methods previously reported on papers. The data was provided as average, minimum and maximum values to assess whether the statistical differences between the GM crops and comparative non-GM crops fall within the biological differences or tolerances of the existing commercial crops. The Crop Composition DB is an open-access source and is easy to access based on the query selected by the user. Moreover, functional ingredients of colored crops, such as potatoes, sweet potatoes and cauliflowers, were provided so that food information can be used and utilized by general consumers. This paper introduces the feature and usage of 'Crop Composition DB', which is a valuable tool for characterizing the composition of conventional crops.

• Journal of Korean Library and Information Science Society
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• v.53 no.1
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• pp.55-79
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• 2022

In this study, the current status of operation was analyzed with a view to analyze the areas in need of improvement and the status of portals of similar institutions. Based on which, a proposal was made to help improve the function of utilization as well as search the products of studies by and for the research institutes funded by the government having jurisdiction by applying the information service technology developing in line with the fourth industrial revolution for the purposes of aiding and fostering with efficiency toward achieving the goal of establishment for such institutes, while strengthening the utility of NKIS. First, in order to secure the membership, it is necessary to find the targets for policy information and promotion, and it is also necessary to increase the demand for policy information, such as by preparing the people friendly policy reports, infographics, and information delivery in an easy manner. Second, it is necessary to provide customized services in the manner which reinforces reports and policy data on the social issues and education topics, which are among the interests of the primary user base by considering the ratio of visiting occupations. Third, for the diversification and expansion of video data services, it is necessary to prepare alternatives, such as by setting regulations and encouraging the institutions of jurisdiction to upload the video data. Fourth, it will be necessary to improve the overall public relations service. It is also necessary to proceed with the NKIS' publicity webtoon serialization with the latest contents or abolish the current webtoon promotion, while it is necessary to derive the plans for the efficient implementation of the contest, further to the need to discuss the secondary publicity after the contest rather than halting after it.

• Information Systems Review
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• v.25 no.3
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• pp.99-120
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• 2023

Courier services users' experience of violating privacy affects psychology and behavior of protecting personal privacy. Depending on what privacy infringement experience (PIE) of courier services users, learning about perceived privacy infringement incidents is made, recognition is formed, affection is formed, and behavior is appeared. This paradigm of changing in privacy psychologies of courier services users has an important impact on predicting responses of privacy protective action (PPA). In this study, a theoretical research framework are developed to explain the privacy protective action (PPA) of courier services users by applying attitude theory. Based on this framework, the relationships among past privacy infringement experience (PIE), perceived privacy risk (PPR), privacy concerns (i.e., concerns in unlicensed secondary use (CIUSU), concerns in information error (CIE), concerns in improper access (CIA), and concern in information collection (CIC), and privacy protective action (PPA) are analyzed. In this study, the proposed research model was surveyed by people with experience in using courier services and was analyzed for finding relationships among research variables using structured an equation modeling software, SMART-PLS. The empirical results show the causal relationships among PIE, PPR, privacy concerns (CIUSU, CIE, CIA, and CIC), and PPA. The results of this study provide useful theoretical implications for privacy management research in courier services, and practical implications for the development of courier services business model.