• Journal of the Society of Naval Architects of Korea
• /
• v.33 no.1
• /
• pp.90-97
• /
• 1996

The optimal mesh refinement has a meaning that error of the every element is within an allowable level and in uniformly distributed. The adaptive mesh generation may be required to achieve the optimal mesh generation. For the purpose of optimal mesh generation, an error estimation and an adaptive mesh refinement are required. Using the adaptive mesh generation the second finite element analysis is performed with the result of the first analysis. In the process the error estimation is required. In this study the adaptive mesh generation program for triangular element is developed, and for a posteriori error estimation the stress projection approach is considered. It has been found the multigrid technique, where the error estimation and the mesh generation are combined in multi-step of analysis, may be used efficiently in the finite element analysis.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.48 no.1
• /
• pp.157-165
• /
• 2011

It is challenging to detect foreground objects when background includes an illumination variation, shadow or structural variation due to its motion. Basically pixel-based background models including codebook-based modeling suffer from statistical randomness of each pixel. This paper proposes an algorithm that incorporates Markov random field model into pixel-based background modeling to achieve more accurate foreground detection. Under the assumptions the distance between the pixel on the input imaging and the corresponding background model and the difference between the scene estimates of the spatio-temporally neighboring pixels are exponentially distributed, a recursive approach for estimating the MRF regularizing parameters is proposed. The proposed method alternates between estimating the parameters with the intermediate foreground detection and estimating the foreground detection with the estimated parameters, after computing it with random initial parameters. Extensive experiment is conducted with several videos recorded both indoors and outdoors to compare the proposed method with the standard codebook-based algorithm.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.8
• /
• pp.18-24
• /
• 2017

The process of transmitting messages through a medium with a limited bandwidth or channel dispersion inevitably involves signal distortion and noise influxes, resulting in the degradation of transmission quality due to the inter-symbol interference and additional noise, which increases the error rate of the received symbols. The main role of the equalizer is to remove the channel distortion and noise from the received signal to recover the transmitted messages. A number of studies on the equalizer composed of a combination of linear filter and error control coding have shown that they played a key role in enhancing the transmission efficiency, which is essential for digital communication. This paper proposes a new algorithm to correct the residual symbol errors in the message signal. In general, equalizer performance improvement algorithms were developed to improve the initial convergence speed or steady-state error. In this paper, however, the equalizer input signal was reconstructed using the equalizer decision symbols and the channel estimates to directly correct the decision errors by analyzing the statistical characteristics of the difference signal between the actual received signal and the reconstructed signal.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2009.10a
• /
• pp.595-598
• /
• 2009

최근 영재 및 영재교육에 관련된 연구가 다방면에서 진행되고 있으며, 초기에 수학 및 과학 분야 위주로 이루어졌던 영재교육은 정보, 발명, 인문, 예술 등의 기타 분야로 점차 확대되어 가고 있다. 사회적으로는 고도화된 정보화 사회로의 진행과 더불어 정보과학에서도 영재교육데 대한 관심과 중요성이 커지고 있다. 그러나 정보과학의 학문적 역사가 짧고 그 범위의 설정이 어려운 만큼 정보과학 분야의 영재교육에 있어서도 대상자의 선발과 교육이 어려운 것이 사실이다. 특히 영재교육 대상자의 선정과 교육에 필수적인 평가 방식에 대한 학문적 연구가 부족하여 교육 방식의 보완과 창의적인 대상자 선발에 있어 개선에 대한 목소리가 높다. 이에 본 연구에서는 여러 형태의 평가 방식 중 관찰평가가 평가도구로서 어떻게 작용하는지 다면 평가의 측면에서 지필평가와 보완적 작용을 하는지에 대해 연구하였다. 이를 위해 2년간의 학습자들의 지필평가 성적과 관찰평가 중 리커트 척도 방식의 체크리스트와 서술형 관찰 기록지 사이의 상관관계를 통계적으로 분석 하였다. 또한 항목간의 상관관계를 알아보기 위해 체크리스트와 서술형 관찰기록지의 하위 항목간의 상관관계를 분석하였다. 연구 결과 체크리스트의 하위항목 분석을 통해서는 태도와 문제해결 능력 간의 상관관계, 수학적인지영역과 문제해결 능력 간의 유의미한 상관 관계를 알 수 있었으며, 서술형 관찰 기록지 분석을 통해서는 투입 프로그램 적응 능력이라 할 수 있는 과정적 영역은 정의적 영역과 인지적 영역의 상관 관계가 중요함을 알 수 있었다. 또한 평가 방식간의 상관 관계는 지필 평가와 관찰 평가의 유의미한 연관성이 없다는 것이 밝혀졌다. 즉, 정보과학 분야 영재교육 학습자의 잠재 능력이나 사회성, 창의성, 문제해결력 등을 평가하기 위해서는 지필평가와 더불어 관찰평가가 반드시 필요하며 다면평가의 측면에서 상호 보완적인 역할을 한다는 것이다.

• Journal of the Korea Society of Computer and Information
• /
• v.26 no.9
• /
• pp.27-35
• /
• 2021

Artificial life is used in various fields of applied science by evaluating natural life-related systems, their processes, and evolution. Research has been actively conducted to evolve physical body design and behavioral control strategies for the dynamic activities of these artificial life forms. However, since co-evolution of shapes and neural networks is difficult, artificial life with optimized movements has only one movement in one form and most do not consider the environmental conditions around it. In this paper, artificial life that co-evolve bodies and neural networks using predator-prey models have environmental adaptive movements. The predator-prey hierarchy is then extended to the top-level predator, medium predator, prey three stages to determine the stability of the simulation according to initial population density and correlate between body evolution and population dynamics.

• The Journal of the Korea Contents Association
• /
• v.21 no.7
• /
• pp.20-29
• /
• 2021

With the creation of a multi-platform media environment, contents production flows through convergence are being detected in the broadcasting contents sector, breaking the boundary between each other and breaking away from the rigid atmosphere of the past, when broadcasters were strictly divided or careful to comment on other programs. It is also quite encouraging that the method of collaboration has been done horizontally as a win-win strategy of co-existence and co-existence, not vertically based on one side's recognition or program popularity. Thus, this study noted the establishment of a world view to capture transmedia phenomena that transcend boundaries between each other to adapt and survive the rapidly reshaping media ecosystem at the base of this trend and to maintain the type of convergence and unrivaled value that emerges in various forms in the process. The research targets were selected for 'Usanseul' and 'Pengsoo', which are prominent in these movements and produce significant results at this point, and analyzed and compared to the results.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.7
• /
• pp.370-379
• /
• 2020

The purpose of this study is to estimate the longitudinal changes in the academic achievement of Korean adolescents who transition from elementary to middle school and examine the individual and social factors of the changes using piecewise growth modeling. For this study, the Multicultural Adolescents Panel Study (MAPS) data from 1st to 6th waves (4th-9th grade) were used. The results are as follows. First, the results showed that the piecewise growth function was the most appropriate method to explain changes in the academic achievement of Korean adolescents with respect to the time of vacation. Second, adolescents' academic achievement declined constantly and was greater for middle school students. Third, parental efficacy, self-esteem, and support from friends had a significant positive effect, while uninvolved parenting and acculturation stress had a significant negative effect on the initial value of academic achievement. Self-esteem and support from friends in the 4th grade prohibit its decline in the first change rate of academic achievements. Meanwhile, acculturation stress for 4th-grade students accelerates the decline of academic achievement.

• The Journal of the Korea Contents Association
• /
• v.18 no.8
• /
• pp.36-50
• /
• 2018

The subjects of this study are three visually-impaired undergraduates currently considering if they should take a leave of absence after finishing the first year in S University located in Busan City. From March to July, 2018, this researcher explored the meaning of their university entrance and the essential meaning and structure of their school life experiences by using Giorgi's phenomenological methodology. According to the results, this author drew 32 meaningful statements and also 10 main themes, "the excitement of campus life and the name of being an undergraduate", "parents' suggestion", "something other than being a massager", "Is it a place that anyone can enter? Or, is it a special place?", "loneliness within the public", "Everything is an obstacle.", "It's not giving up, but still I am in a vague moment.", "the beginning of another conflict", and "studying in a university is not for the present but for the future". They were categorized into being a university student and the meaning of it (category1), adaptation to university life and reality (category 2), and one year after the entrance: the meaning of being a university student (category 3). Based on the above results, this author intends to provide foundational material about what universities can do for visually-impaired students to adapt to university life in the initial steps properly.

• The Korean Journal of Malacology
• /
• v.32 no.3
• /
• pp.175-184
• /
• 2016

In this study, we transplanted Chinese (Liaoning Dandong) and Chungnam (Taean) manila clam seeds to Gochang tidal flats in Jeonbuk province, and compared growth, mortality, and condition indices from May 2015 to August 2016. Within 2 months after transplantation, clam mortality of Chungnam and Chinese origin were $6.9{\pm}4.3%$, $16.9{\pm}7.9{\sim}21.0{\pm}6.3%$, respectively. We supposed that higher mortality of Chinese manila clams might be due to higher stress and weakening of physiological functions by air-exposure and unavailability of food intake for 5 days harvesting, transportation, quarantine procedures. Unlike the local clam farmer's opinion based on their field experience, growth of Chungnam clams in shell length and total weight were a little better than Chinese without statistical significant difference (P > 0.05). Condition indices of Chinese clams showed declining tendency after reaching a peak in May 2014, and in June 2015, respectively. Meanwhile, Chungnam clams has reached its peak of condition indices in May 2014 and in April 2015, respectively. From this result, we supposed that there might be at least one month difference in reproduction between the Chinese and Chungnam manila clams during the first-transplanted year. Because the mortality of adult clam have sharply increased from June 2015 (due to high temperature, few rainfall and spawning) in Gochang tidal flat, it would be recommendable that farmers harvest the clams before June when its shell length are larger than 40 mm. In conclusion, we could directly compare the productivity of Chinese and Chungnam manila clam at Gochang tidal flats by field experiment, and these results are also meaningful to manila clam farmers.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.13 no.6
• /
• pp.177-189
• /
• 2018

Business environment is always full of challenges. Despite various strategic efforts, there are so many failure cases of misfit. With the weaker resource base and institutional foundation, startup firms find it more difficult to find the right spot in the stiff competition. In the middle of evolutionary process, the startup firms need proper strategies meeting the differential challenges along the multiple stages of growth. Following the idea of product life cycle, this study applies the four stages of growth-startup, initial growth, accelerated growth, matured, and decliing. The next step for the startup manager is meeting each stage of growth with proper strategic efforts, including strategy, structure, decision-making pattern, and control method. When the knowledge factor is introduced, there is a potential for higher performance. Based on the 'Detailed Survey on Startup Ventures in 2017,' this study explores the impact of the government subsidy program on the firm competitiveness and performance-along the four stages of growth. In each stage, the strategy factors showed differential impact.