• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.571-573
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• 2009

Mobile Ad-hoc Network(MANET) needs efficient node management because the wireless network has energy constraints. Mobility of MANET would require the topology change frequently compared with a static network. To improve the routing protocol in MANET, energy efficient routing protocol would be required as well as considering the mobility would be needed. Previously proposed a hybrid routing CACH prolong the network lifetime and decrease latency. However the algorithm has a problem when node density is increase. In this paper, we propose a new method that the CACHE(Context-aware Clustering Hierarchy and Energy efficient) algorithm. The proposed analysis could not only help in defining the optimum depth of hierarchy architecture CACH utilize, but also improve the problem about node density.

• The Korean Journal of Emergency Medical Services
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• v.23 no.2
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• pp.7-18
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• 2019

Purpose: This study aimed to determine the core competencies for 119 emergency medical technicians (EMTs) and to provide evidence for the development and utilization of 119 EMTs, education and training programs. Methods: Data were collected with a questionnaire that consisted of items on the general characteristics of the subjects (8 items) and importance and satisfaction levels for 10 competencies, including 34 items on subfactors. The Borich Needs Assessment Model was used in designing the questionnaire. A locus for focus model was used to derive the top priority competencies for the improvement of core competency in the profession. Data were analyzed with by SPSS ver.21 (IBM, Armonk, NY, USA). Results: The core competencies for 119 EMTs were derived from technical competency, information competency, communication competency, problem-solving competency, self-development competency and interpersonal competency. In addition, among the sub-factors of these competencies, 16 abilities (including leadership), ability to apply technical knowledge, technical comprehension, conflict management ability, ability to create documents, problem handling ability, ability to think, technical selection ability, and computer literacy were included in the priority category. Conclusion: This study derived and presented the core competencies for 119 EMTs to enable them to meet the modern day requirements of their roles, which may contribute to enhancing their professionalism.

• International Journal of Computer Science & Network Security
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• v.21 no.9
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• pp.31-40
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• 2021

The increasing number of credit card fraud cases has become a considerable problem since the past decades. This phenomenon is due to the expansion of new technologies, including the increased popularity and volume of online banking transactions and e-commerce. In order to address the problem of credit card fraud detection, a rule-based approach has been widely utilized to detect and guard against fraudulent activities. However, it requires huge computational power and high complexity in defining and building the rule base for pattern matching, in order to precisely identifying the fraud patterns. In addition, it does not come with intelligence and ability in predicting or analysing transaction data in looking for new fraud patterns and strategies. As such, Data Mining and Machine Learning algorithms are proposed to overcome the shortcomings in this paper. The aim of this paper is to highlight the important techniques and methodologies that are employed in fraud detection, while at the same time focusing on the existing literature. Methods such as Artificial Neural Networks (ANNs), Support Vector Machines (SVMs), naïve Bayesian, k-Nearest Neighbour (k-NN), Decision Tree and Frequent Pattern Mining algorithms are reviewed and evaluated for their performance in detecting fraudulent transaction.

• Journal of Korean Elementary Science Education
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• v.35 no.2
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• pp.181-193
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• 2016

We examined the inquiry activities in the material domain of the elementary science textbooks and experimental workbooks based on 2009 revised curriculum. The analysis framework was SEP (Science and Engineering Practices) - 'Asking questions and defining problems', 'developing and using models', 'planning and carrying out investigations', 'analyzing and interpreting data', 'using mathematics and computational thinking', 'constructing explanations and designing solutions', 'engaging in argument from evidence', and 'obtaining, evaluating, and communicating information'. Sub-SEP of each grade band were also used. The results showed that the $3^{rd}{\sim}5^{th}$ grade science textbooks and workbooks mainly emphasized 'make observations and/or measurements', 'represent data in tables and/or various graphical displays', or 'use evidence to construct or support an explanation or design a solution to a problem' among around 40 sub-SEP. In the case of the inquiry activities for $6^{th}$ grade, majority of sub-SEP included were also only 'collect data to produce data to serve as the basis for evidence to answer scientific questions or test design solutions', 'analyze and interpret data to provide evidence for phenomena' or 'construct a scientific explanation based on valid and reliable evidence obtained from sources'. The type of 'asking questions and defining problems', 'using mathematics and computational thinking' or 'obtaining, evaluating, and communicating information' were little found out of 8 SEP. Educational implications were discussed.

• Safety and Health at Work
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• v.6 no.3
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• pp.159-173
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• 2015

The hand coordinate systems for measuring vibration exposures and biodynamic responses have been standardized, but they are not actually used in many studies. This contradicts the purpose of the standardization. The objectives of this study were to identify the major sources of this problem, and to help define or identify better coordinate systems for the standardization. This study systematically reviewed the principles and definition methods, and evaluated typical hand coordinate systems. This study confirms that, as accelerometers remain the major technology for vibration measurement, it is reasonable to standardize two types of coordinate systems: a tool-based basicentric (BC) system and an anatomically based biodynamic (BD) system. However, these coordinate systems are not well defined in the current standard. Definition of the standard BC system is confusing, and it can be interpreted differently; as a result, it has been inconsistently applied in various standards and studies. The standard hand BD system is defined using the orientation of the third metacarpal bone. It is neither convenient nor defined based on important biological or biodynamic features. This explains why it is rarely used in practice. To resolve these inconsistencies and deficiencies, we proposed a revised method for defining the realistic handle BC system and an alternative method for defining the hand BD system. A fingertip-based BD system for measuring the principal grip force is also proposed based on an important feature of the grip force confirmed in this study.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.3
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• pp.313-324
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• 2013

It is widely known that untreated Combined Sewer Overflows (CSOs) that directly discharged from receiving water have a negative impact. Recent concerns on the CSO problem have produced several large scale constructions of treatment facilities, but the facilities are normally designed under empirical design criteria. In this study, several criteria for defining CSOs (e.g. determination of effective rainfall, sampling time, minimum duration of data used for rainfall-runoff simulation and so on) were investigated. Then this study suggested a standard methodology for the CSO calculation and support formalized standard on the design criteria for CSO facilities. Criteria decided for an effective rainfall was over 0.5 mm of total rainfall depth and at least 4 hours should be exist between two different events. An Antecedent dry weather period prior to storm event to satisfy the effective rainfall criteria was over 3 days. Sampling time for the rainfall-runoff model simulation was suggested as 1 hour. A duration of long-term simulation CSO overflow and frequency calculation should be at least recent 10 year data. A Management plan for the CSOs should be established under a phase-in of the plan. That should reflect site-specific conditions of different catchments, and formalized criteria for defining CSOs should be used to examine the management plans.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.6
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• pp.663-668
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• 2012

Fly ash erosion is a leading cause of boiler tube failure in PC boilers. Therefore, shields or baffle plates are installed in specific areas to mitigate fly ash erosion and prevent boiler tube failure. However, the tube failure problems caused by fly ash erosion cannot be eliminated with this solution alone, because each PC boiler has a different flue-gas flow pattern and erosion can become severe in unexpected zones. This problem is caused by an asymmetric internal flow velocity and local growth of the flue gas velocity. For these reasons, clearly defining the flow pattern in PC boilers is important for solving the problem of tube failure caused by fly ash erosion. For this purpose, the cold air velocity technique (CAVT) can be applied to the fly ash erosion problem. In this study, CAVT was carried out on the Hadong #2 PC boiler and the feasibility of application of CAVT to conventional PC boilers was validated.

• Korean Institute of Interior Design Journal
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• v.18 no.5
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• pp.71-79
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• 2009

This research understands semantics-system in contemporary space design as a poetic form. It provides that the possibility of various interpretation of space and makes to escape from insipid formal logic of compulsion uniform meaning. In order to unfold this argument, poetic semantics system has to be revealed using conversion of articulation factors in text of space(semantics and syntax). First of all, after setting up the articulation system of space language, we have to understand the conversion of articulation factors that generate a new grammar breaking up the rule of old syntax. And the various expression of form in Contemporary Space design focuses on a poetic expression, that is, the abstraction system fused by space factors(conversion of articulation system). In this method of research to recognize the subject of space in architecture, the importance of interpretation has to be highlighted, as the importance of language is emphasized that intermediates between object and interpretation. The reason to recognize Contemporary space design as a text is that it is a gathering of symbol as a object of interpretation and a mediator. The important issue of this study is to research how and what to transmit by poetic semantics system in contemporary space design. It brings about a poetic problem what it intends to becomes(the problem of meaning operation) in a narrow sense and a interpretational problem what it intends to do(the problem of communication). When we define interpretation the technique of defining a text, it involves the premise of inevitableness of multiple understanding, or the possibility to Interpret variously. In the end the ambiguity of poetic language and the infinity of moaning process as the moaning expansion system in contemporary space design is the flexible measure to solve the self-criticism.

• Journal of Korea Society of Industrial Information Systems
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• v.24 no.6
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• pp.11-24
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• 2019

The tendency of buyers of web information is changing from the cost-effectiveness to the cost-satisfaction. There is such tendency in the recommendation of multimedia contents, some of which are folksonomy-based recommendation services using mood. However, there is a problem that they does not consider synonyms. In order to solve this problem, some studies have solved the problem by defining 12 moods of Thayer model as AV values (Arousal and Valence), but the recommendation performance is lower than that of a keyword-based method at the recall level 0.1. In this paper, we propose a method based on using mood vector of multimedia contents. The method can solve the synonym problem while maintaining the same performance as the keyword-based method even at the recall level 0.1. Also, for performance analysis, we compare the proposed method with an existing method based on AV value and a keyword-based method. The result shows that the proposed method outperform the existing methods.

• Research in Mathematical Education
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• v.17 no.2
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• pp.119-131
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• 2013

It is the first time that there is a subject, advanced mathematics in the 2009 revised high school curriculum. Therefore it is posing a challenge to the teachers who are teaching it. At the advanced level, it is important for learners to reflect on their mental mathematical activities. This research analysed pre-service secondary teachers' reflective thinking in solving the tasks specific for the teaching and learning of polar coordinates. We report how and through what process mathematical tasks that can create disequilibrium for pre-service secondary teachers enable reflective thinking and expand preservice secondary teachers' thoughts and recognition of defining reflective thinking in looking back on one's problem solving and thinking processes.