• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.144-147
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• 2006

A proportional intergral (PI) control strategy is commonly used for constant current and extinction angle control in a HVDC (High Voltage Direct Current) system. A PI control strategy is based on a stactic design where the gains of a PI controller are fixed. Since the response of a HVDC plant dynamically changes with variations in the operation point a PI controller performance is far from optimum. The contribution of this paper is the presentation of the design of a rough set based, fuzzy adaptive control scheme. Experimental results that compare the performance of the adaptive control and PI control schemes are also given.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.145-146
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• 2006

Recently, the next-generation advanced flow visualization techniques such as holographic PIV, dynamic PIV, echo-PIV, micro/nano-PIV, and X-ray PIV have been introduced. These advanced measurement techniques have a big potential as the core technology for analyzing outmost thermo-fluid flows in future. These would be indispensable in solving complicated thermo-fluid flow problems not only in the industrial fields such as automotive, space, electronics, aero- and hydro-dynamics, steel, and information engineering, but also in the research fields of medical science, bio-medical engineering, environmental and energy engineering etc. Especially, NT (Nano Technology) and BT (Bio Technology) strongly demand these advanced measurement techniques, because it is impossible for conventional measurement methods to observe most complicated nano- and bio-fluidic phenomena. In this presentation, the basic principle of these high-tech flow visualization techniques and their practical applications which cannot be resolved by conventional methods, such as blood flows in a micro-tube, in vivo analysis of micro-circulation, and flow around a living body will be introduced as a blue ocean strategy.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.3-3
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• 2021

The ongoing global pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has not only influenced over 1.26 billion people but also caused 2.77 million deaths worldwide (as of March 28, 2021). The vaccination could be the most efficient strategy to prevent SARS-CoV-2 infection. However, the continuous emergence of novel variants such as VUI-202012/01 (United Kingdom) and 501.V2 (South Africa) raises huge concerns about the effectiveness of the vaccine designed to target the original virus strain. Since ancient times regardless of the East and West, the plants which refered in this presentation have been consumed not only as food but also as a natural medicine to treat diverse diseases including infectious diseases. Importantly, these plants contain secondary metabolites that display antiviral activity involved in the inhibition of viral adsorption, penetration, and replication. Also, plant-derived natural medicines are expected to have a wider range of efficacy and fewer side effects than synthetic medicine, discovering novel plant-based viral agents would be a promising strategy to fight against SARS-CoV-2.

• Journal of Korean Elementary Science Education
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• v.38 no.1
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• pp.73-86
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• 2019

The purpose of this study is to investigate the characteristics of problem solving strategies that gifted students use in science inquiry problem. The subjects of the study are the notes and presentation materials that the 15 team of elementary and junior high school students have solved the problem. They are a team consisting of 27 elementary gifted and 29 middle gifted children who voluntarily selected topics related to dimple among the various inquiry themes. The analysis data are the observations of the subjects' inquiry process, the notes recorded in the inquiry process, and the results of the presentations. In this process, the knowledge related to dimple is classified into the declarative knowledge level and the process knowledge level, and the strategies used by the gifted students are divided into general strategy and supplementary strategy. The results of this study are as follows. First, as a result of categorizing gifted students into knowledge level, six types of AA, AB, BA, BB, BC, and CB were found among the 9 types of knowledge level. Therefore, gifted students did not have a high declarative knowledge level (AC type) or very low level of procedural knowledge level (CA type). Second, the general strategy that gifted students used to solve the dimple problem was using deductive reasoning, inductive reasoning, finding the rule, solving the problem in reverse, building similar problems, and guessing & reviewing strategies. The supplementary strategies used to solve the dimple problem was finding clues, recording important information, using tables and graphs, making tools, using pictures, and thinking experiment strategies. Third, the higher the knowledge level of gifted students, the more common type of strategies they use. In the case of supplementary strategy, it was not related to each type according to knowledge level. Knowledge-based learning related to problem situations can be helpful in understanding, interpreting, and representing problems. In a new problem situation, more problem solving strategies can be used to solve problems in various ways.

• Fashion & Textile Research Journal
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• v.14 no.5
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• pp.778-790
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• 2012

This research categorizes and analyzes different online fashion store studies conducted over the past 10 years based on study type. The results are as follows. First, it was found that 116 studies out of 118 studies on online fashion stores conducted from 2000 to 2012 were based on PC web. Second, the studies on PC web-based fashion stores were reclassified into 9 different categories based on their topics: purchase behavior, word-of-mouth behavior, website, and product information presentation as well as products for sale, return behavior, customer service, system, present condition, marketing strategy, and promotions. However, mobile web-based studies were categorized into 2 categories of introduction of the fashion stores and purchase behavior. Third, we reclassified the studies chronologically to observe studies conducted at different times. In the early phase (in addition to studies on purchase behavior) studies on present condition, marketing strategy, and website constituted the majority of studies conducted because the field research was just starting to grow; however, studies conducted in the latter phase showed new patterns of study, such as word-of-mouth effect, and return behavior. Future studies conducted on competitive PC web-based fashion stores require a more specific classification of studies (according to their purpose) to develop an effective marketing strategy.

• Korean Journal of Poultry Science
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• v.26 no.2
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• pp.131-144
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• 1999

Coccidiosis, an intestinal infection caused by intracellular protozoan parasites belonging to several different species of Eimeria seriously impairs the growth and feed utilization of livestock and poultry. Due to complex life cycle of organism and intricate host immune responses to Elmeria, coccidia vaccine development has been difficult. Understanding of basic imunobiology of pertinent host-parasite interactions is necessary for the development of novel control strategy. Although chickens infected with Eimeria spp. produce parasite-specific antibodies in both the circulation and mucosal secretions, antibody mediated responses play a minor role in protection gainst coccidiosis. Rather, increasing evidence show that cell-mediated immunity plays a major role in resistance to coccidiosis. T-lymphocytes appear to respond to coccidiosis both through cytokine production and a direct cytotoxic attack on infected cells. The exact mechanisms by which T-cells eliminate the parasites, however, remain to be investigated. Since it is crucial to understand the intestinal immune system in order to develop an immunological control strategy against any intestinal immune system in order to develop an immunological control strategy against any intestinal diseases, this presentation will summarize our current understanding of the avian intestinal immune system and mucosal immune responses to Eimeria, to provide a conceptual overview of the complex molecular and cellular events involved in intestinal immune responses to enteric pathogens.

• Journal of the Korean School Mathematics Society
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• v.13 no.2
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• pp.225-241
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• 2010

Even though geometry is an important part basic to mathematics, studies on the program designs and teaching strategies of geometry are insufficient. The aims of this study are to propose the model of program design for autonomous learners taking their characteristics of the mathematically gifted into consideration. The core of teaching materials are analytic geometry and projective geometry. And the new teaching strategy will introduce three steps ; a draft strategies step(problem presentation, problem solving), a supportive strategies step(abstraction of a mathematical concept, mathematical induction, and extension), a transference strategies step to teaching strategy suitable for mathematically gifted. As a result, this study will suggest the effective methods of geometry teaching for the mathematically gifted.

• Journal of Korean Elementary Science Education
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• v.39 no.2
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• pp.228-242
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• 2020

The purpose of this study is to develop a student-led instructional strategy that is central to the teaching-learning process and to investigate its effects. For this study, we analyzed the learner-centered learning types (discovery learning, problem-based learning, inquiry learning) and extracted elements applicable to newly developed teaching-learning. Based on this, a student-led class strategy was established using pre-learning, teacher collaboration, small group composition, and limited open data and product presentation, and then science classes were conducted. As a result of the post-tests of the five science core competencies of the experimental group using the student-led instructional strategy and the comparative group conducting lecture-based classes, the experimental group showed higher scores than the comparative group in the scientific thinking, scientific communication, and scientific attitudes (p<.05). Based on these results, it was confirmed that the student-led class, in which the student self-adjusts the entire process of designing, exploring, and presenting learning, can help the student's scientific ability. In addition, I would like to discuss the implications of teachers' teaching-learning composition.

• Korean Institute of Interior Design Journal
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• v.22 no.5
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• pp.68-77
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• 2013

'The Third space,' which is the concept that embraces sociological, spatial, and marketing concepts, refers to the place which is other than the home and the workplace and which is a comfortable frequented place where meditation, psychological relaxation, and social needs can be satisfied. 'The Third space' has the characteristics of comfort, openness, interactivity, playfulness, and diversity. In modern times, most of consumption spaces play the role of 'the Third space,' and the typical example is $Caf{\acute{e}}$. $Caf{\acute{e}}$ began from its origin with the characteristics of 'the Third space,' and recently it has become the complex cultural space of urban dwellers. $Caf{\acute{e}}$ as 'the Third space' has the characteristics of a healing space, communication space, personalized space, value-expressive space, culture and consumption space, nomad space. Such characteristics of $Caf{\acute{e}}$ are well represented in the cafes around the regions where 'street culture' has recently been formed. As examined through the examples, $Caf{\acute{e}}$ as 'the Third space' can be more strategically produced by establishing themes through storytelling, giving spatial identity through style creation, diversifying the sequence through complex space organization, and establishing interaction devices through experience elements.

• Journal of Information Technology Applications and Management
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• v.25 no.2
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• pp.1-21
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• 2018

This study aims to investigate the usage patterns of users in Social Network Services (SNS) where is an upsurge. Specifically, the paper considers the reason why young people more and more prefer online (or mobile) SNS activities rather than offline face-to-face social relationship. Furthermore, the drivers which affect SNS usages are considered from users' personal characteristics and social influences. User's personal characteristics include their personalities (extraversion and introversion), narcissism, and life satisfaction. Social influences involve subjective norm, visibility, and image. Affected by personal and social factors in SNS, users intend to show positive self-presentation, which refers to a behavior to selectively expose his/her goodness to others. As one of the most influential drivers affecting SNS usage, the positive self-representation has an effect on the level of SNS usage. Thus, this paper suggests the hypothesized research model focusing on positive self-representation in the relationship among personal characteristics, social influence, and user's behavior in SNS. Empirical data analysis with 100 questionnaires suggests that all hypotheses were adopted except for the effect of visibility among social influence factors on positive self-representation.