• Journal of the Korean Society of Propulsion Engineers
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• v.13 no.2
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• pp.26-34
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• 2009

Secondary flow losses can be as high as 30~50% of the total aerodynamic losses for a turbo-machinery blade or stator row. These are important part for improving a turbine efficiency. Therefore, many studies have been performed to decrease the secondary flow losses. The present study deals with the chamfered leading-edge at a generic wing-body junction to decrease the horseshoe vortex, one of factors to generate the secondary flow losses, and investigates the vortex generation and the characteristics of the horseshoe vortex with the chamfered height, and depth of the chamfer by using $FLUENT^{TM}$. It was found that the total pressure loss for the best case can be decreased about 1.55% compare to the baseline case.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.7-7
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• 2019

우리나라에서의 대마는 마약류로 분류되어 기호용과 의료용 모두 법적인 제재를 받아왔으나 최근에 의료용 대마가 법적으로 허용이 되어 환자들에게 처방 받을 수 있게 되었다. 하지만 우리나라 사람들에게 대마는 환각성분을 가진 마약류로 깊이 인식되어 왔으며 의료용 대마에 대한 연구는 거의 전무한 실정이다. 노지재배에서 발생할 수 있는 범죄의 위험성, 자연교배에 의한 품질저하를 피할 수 있으며 재배조건(양액, 광조건, 광주기, 대기환경조성) 등을 제어할 수 있는 밀폐형 LED 식물공장은 의료용 대마 생산에 제일 적합한 모델이 될 수 있다. 식물체의 광합성은 가시광선 중 특정 파장 450nm 청색광과 660nm 적생광을 주로 이용하며 'LED (Light Emitting Diode) 발광다이오드'는 식물체의 광합성에 적합한 파장으로 광원을 조사할 수 있는 장점이 있다. 이러한 LED를 이용한 광합성은 식물체의 2차 대사물질 Anthocyanins, phenolic compounds 등의 향상과 생육에도 긍정적인 영향을 미치며 식물 뿐만 아니라 광합성을 하는 미세조류(micro algae)에서도 이용이 가능하며 해마토 코쿠스(Hematococcus)의 세포증식과 항산화물질 아스타잔틴(astaxathin)생산에 유용하게 쓰이고 있다. 최근 미국과 다른 나라에서도 기호용, 의료용 대마사업에 대한 관심이 높아지고 있으며 캐나다와 미국에서는 밀폐형 유리온실과 식물공장을 이용한 의료용 대마를 생산, 추출, 가공까지 하여 산업적인 영역을 넓히고 있는 실정이다. 특히, 실내재배에서는 광원이 필수적인 요소이며 식물생육에 선택적인 파장을 조사할 수 있는 LED와 재배조건을 정밀하게 제어할 수 있는 밀폐형 식물공장을 이용한 의료용 대마 생산에 대한 연구가 절실히 필요한 시점이다.

• Smart Media Journal
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• v.11 no.9
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• pp.47-55
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• 2022

Quality control in the smart factory manufacturing process is an important factor. Currently, quality inspection of home appliance manufacturing parts produced by the mold process is mostly performed with the naked eye of the operator, resulting in a high error rate of inspection. In order to improve the quality competition, an automatic defect detection system was designed and implemented. The proposed system acquires an image by photographing an object with a high-performance scan camera at a specific location, and reads defective products due to scratches, dents, and foreign substances according to the vision inspection algorithm. In this study, the depth-based branch decision algorithm (DBD) was developed to increase the recognition rate of defects due to scratches, and the accuracy was improved.

• Journal of Internet Computing and Services
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• v.14 no.5
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• pp.1-10
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• 2013

RFID(Radio Frequency Identification) system is non-contact identification technology. A basic RFID system consists of a reader, and a set of tags. RFID tags can be divided into active and passive tags. Active tags with power source allows their own operation execution and passive tags are small and low-cost. So passive tags are more suitable for distribution industry than active tags. A reader processes the information receiving from tags. RFID system achieves a fast identification of multiple tags using radio frequency. RFID systems has been applied into a variety of fields such as distribution, logistics, transportation, inventory management, access control, finance and etc. To encourage the introduction of RFID systems, several problems (price, size, power consumption, security) should be resolved. In this paper, we proposed an algorithm to significantly alleviate the collision problem caused by simultaneous responses of multiple tags. In the RFID systems, in anti-collision schemes, there are three methods: probabilistic, deterministic, and hybrid. In this paper, we introduce ALOHA-based protocol as a probabilistic method, and Tree-based protocol as a deterministic one. In Aloha-based protocols, time is divided into multiple slots. Tags randomly select their own IDs and transmit it. But Aloha-based protocol cannot guarantee that all tags are identified because they are probabilistic methods. In contrast, Tree-based protocols guarantee that a reader identifies all tags within the transmission range of the reader. In Tree-based protocols, a reader sends a query, and tags respond it with their own IDs. When a reader sends a query and two or more tags respond, a collision occurs. Then the reader makes and sends a new query. Frequent collisions make the identification performance degrade. Therefore, to identify tags quickly, it is necessary to reduce collisions efficiently. Each RFID tag has an ID of 96bit EPC(Electronic Product Code). The tags in a company or manufacturer have similar tag IDs with the same prefix. Unnecessary collisions occur while identifying multiple tags using Query Tree protocol. It results in growth of query-responses and idle time, which the identification time significantly increases. To solve this problem, Collision Tree protocol and M-ary Query Tree protocol have been proposed. However, in Collision Tree protocol and Query Tree protocol, only one bit is identified during one query-response. And, when similar tag IDs exist, M-ary Query Tree Protocol generates unnecessary query-responses. In this paper, we propose Adaptive M-ary Query Tree protocol that improves the identification performance using m-bit recognition, collision information of tag IDs, and prediction technique. We compare our proposed scheme with other Tree-based protocols under the same conditions. We show that our proposed scheme outperforms others in terms of identification time and identification efficiency.

• Journal of Hospice and Palliative Care
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• v.19 no.1
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• pp.45-60
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• 2016

Purpose: This study is aimed at understanding the volunteers' experiences and interactions with their corresponding teams during their participation in hospice care. More specifically, the study is to contribute policy-wise to development of hospice care in Korea by helping policy-makers and organizers and managers of hospice care provides better understand the importance of the meaning and roles of volunteers in hospice care. Methods: In-depth interviews and participant observation were performed with study participants who were selected from four different types of hospice agencies. Study analysis was conducted using "case study" as one of the rigorous qualitative research methods to develop "inter-" and "intra-" comparisons among the study participants. Results: Volunteers in hospice care were initially motivated by religion and faith, and the motivation grew stronger through the volunteer experiences. They emphasized that the essence of the hospice volunteering was motivation from religion and faith and something they do for themselves. They characterized their experience as a true service that is offered for free and a job that requires expertise. In addition, they achieved personal (internal) growth by reflecting on the meaning of "good death" and better understood the importance of respecting spiritual diversity. Conclusions: This study could help hospice officials offers better understand hospice volunteers' role and their importance. The study also provide practical implications and policy suggestions.

• Journal of Korea Game Society
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• v.12 no.5
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• pp.79-88
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• 2012

In this paper, we present a real-time hand pose recognition method to provide an intuitive user interface through hand poses or movements without a keyboard and a mouse. For this, the areas of right and left hands are segmented from the depth camera image, and noise removal is performed. Then, the rotation angle and the centroid point of each hand area are calculated. Subsequently, a circle is expanded at regular intervals from a centroid point of the hand to detect joint points and end points of the finger by obtaining the midway points of the hand boundary crossing. Lastly, the matching between the hand information calculated previously and the hand model of previous frame is performed, and the hand model is recognized to update the hand model for the next frame. This method enables users to predict the hidden fingers through the hand model information of the previous frame using temporal coherence in consecutive frames. As a result of the experiment on various hand poses with the hidden fingers using both hands, the accuracy showed over 95% and the performance indicated over 32 fps. The proposed method can be used as a contactless input interface in presentation, advertisement, education, and game applications.

• Communications of Mathematical Education
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• v.29 no.3
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• pp.441-463
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• 2015

The big issue of mathematics education in 2009 revised curriculum is to introduce story-telling in math textbook and to aim toward the math that students can learn easily and interestingly. Therefore, this study examine the perception of middle school teachers in working with story-telling, analyze actual utilization of story-telling in class and provide the basic materials for effective practical application. After making questionnaires to check the real conditions of the story-telling and asking math teachers in charge of the first and second graders, this research came to the conclusion as follows. First, the teachers who took part in this research showed positive perception in story-telling textbook the practical use of a variety of materials and the improvement of thinking faculty and creativity. Second, math teachers made use of a variety of storytelling data and especially reflection media in class, but this was limited in introductory part. Mathematic concept was delivered mainly through the activities of exchanging questions and answers between the teachers and students. Third, students showed positive reaction about story-telling class on the whole. For example, they understood the concept easily and they could apply it in real life. However, story-telling failed to bring the attention and interest of math itself. Therefore, teachers' ability is needed in the way that math knowledge and concept should be formed and expressed interestingly.

• Journal of Korea Multimedia Society
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• v.14 no.10
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• pp.1348-1364
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• 2011

As the existing edutainment contents for children are mostly comprised of educational tools which unilaterally induce educatees to passively respond to them, the content-creating methodologies in terms of which active and voluntary learning is made possible is urgently needed. In this paper, we present the implementation of the tangible 'electronic dice' interface as an interactive tool for behavior-based edutainment contents, and propose a methodology for developing edutainment contents for children by utilizing the recognition technique of hand movement based on depth-image information. Also proposed in the paper are an authoring and management tool of learning quizzes that allows educators to set up and manage their learning courseware, and a log analysis system of learning achievement for real-time monitoring of educational progress. The behavior-based tangible interface and edutainment contents that we propose provide the easy-to-operate interaction with a real object, which augments educatees' interest in learning, thus leading to their active and voluntary attitude toward learning. Furthermore, The authoring and management tool and log analysis system allow us to construct learning programs by children's achievement level and to monitor in real-time the learning development of children educatees by understanding the situation and behavior of their learning development from the analytic results obtained by observing the processes of educatees' solving problems for themselves, and utilizing them for evaluation materials for lesson plans.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.3
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• pp.1382-1389
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• 2014

As an origin and a starting point of business start-up, this start-up intention is believed to be the driving force of economic growth. Being aware of the importance of the start-up intention, the study looked into cause-and-effect relationships of variables focusing on intermediate roles of start-up self-efficacy and intrinsic motivation in self-leadership and start-up intention of business founders. In order to achieve the research goal, the study conducted both a survey targeting a total of 195 business founders registered at a business incubation center and an empirical analysis on the results of the survey. According to the findings from the analysis, the study first learned that the self-leadership would have a positive effect on the start-up self-efficacy and the intrinsic motivation which eventually proved that the self-leadership is a leading variable of the start-up self-efficacy and the intrinsic motivation. Second, both the start-up self-efficacy and the intrinsic motivation were observed to be positively related to the start-up intention. That finding signified that roles of the start-up self-efficacy and the intrinsic motivation are important to increase the start-up intention. Third, intermediate effects of the start-up self-efficacy and the start-up intention were discovered from the self-leadership and the start-up intention, the main topics of the research. Hence, in order to improve the start-up intention, the importance of the start-up self-efficacy and the intrinsic motivation should be recognized and promoted as well and for this goal to be achieved, the business founders should understand the idea that the self-leadership has to come first than anything else in this case. Based on the results of the research, the study offers theoretical and practical implications.

• Korean Journal of Environment and Ecology
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• v.10 no.1
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• pp.14-23
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• 1996

Visitors to Naejangsan National Park were surveyed from October 31 to November 3 in 1995, 151 visitors were participated. Of those individuals, 55% were males. 48% of respondests reported that they had gone beyond high school, and over one-half(52%) had gone as far as college. 61.3% were 20 years of age. The largest percentage of respondents were reported that they visited Naejangsan Nat'l Park to see the scarlet maple leaces there. Most respondents who witness other visitors' littering were not likely to intervene to stop their visitors' depreciative behavior(Bystander intervention Begavior). Most of visitors got information for use Naejangsan Nat'l Park from a guide sign(31.8%) or guide themselves(29.1%). They didn't know the Clean-up Time Movement Program. But they understood it after notice hanging placards(81.6%). Most of visitors responded that didn't hear the mass communication program in National. But they recognized necessity of the mass communication program in National Park. The results showed that most visitors believed that Clean-up Time Movement was in succession consequently it turned out to be effective in managing visitors' littering behavior. And it seemed to effective in managing depreciative behavior through the mass communication program in National Park.