• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.5
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• pp.557-565
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• 2021

Path-following control is considered as one of the most fundamental skills to realize autonomous navigation of marine vessels in the ocean. This study addresses with the path-following control for a ship in which there are environmental disturbances in the directions of the surge, sway, and yaw motions. The guiding principle and back-stepping method was utilized to solve the ship's tracking problem on the reference path generated by a virtual ship. For path-following control, error dynamics is one of the most important skills, and it extends to the research fields of automatic collision avoidance and automatic berthing control. The algorithms for the guiding principles and error variables have been verified by numerical simulation. As a result, most error variables converged to zero values with the controller except for the yaw angle error. One of the most interesting results is that the tracking errors of path-following control between two ships are smaller than the existing safe passing distances considering interaction forces from near passing ships. Moreover, a trade-off between tracking performance and the ship's safety should be considered for determining the proper control parameters to prevent the destructive failure of actuators such as propellers, fins, and rudders during the path-following of marine vessels.

• Journal of Marine Life Science
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• v.4 no.1
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• pp.1-13
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• 2019

Fucoidan is a physiologically functional ingredient extracted from seaweed brown algae, which is a sulfated polysaccharide containing fucose as a main molecule backbone. Fucoidan has a variety of immune-modulating or -stimulating effects, including promoting antigen uptake and enhancing anti-bacterial, anti-viral and anti-tumor effects. In addition, recent studies have suggested the possibility of use of fucoidan as a vaccine adjuvant in the field of human vaccine. Use of fucoidan as supplementary feeds have already been studied, but the development of fucoidan as an adjuvant of fish vaccine is still premature. However, the intracellular uptake of fucoidan differs depending on the molecular weight of fucoidan, and there is a limit to the study on specific immune response including the production of antibodies to fish caused by an artificial infection of pathogen. Although the safety of fucoidan has been demonstrated in animal cells, there is a need to confirm the safety of fucoidan in fish. Therefore, active research in this field is needed to use fucoidan as a vaccine adjuvant. This study discussed the effects of fucoidan on immune stimulation, humoraland cellular- immunity including humans and animals. The prospect of fucoidan as a vaccine adjuvant in fisheries also reviewed.

• Journal of the Society of Disaster Information
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• v.17 no.3
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• pp.655-666
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• 2021

Purpose: This study is to develop a method for measuring dynamic speeding risks using vehicle trajectory big data and to demonstrate the feasibility of the devised speeding index. Method: The speed behaviors of vehicles were analysed in microscopic space and time using individual vehicle trajectories, and then the boundary condition of speeding (i.e., boundary speed) was determined from the standpoint of crash risk. A novel index for measuring the risk exposure of speeding was developed in microscopic space and time with the boundary speed. Result: A validation study was conducted with vehicle-GPS trajectory big data and ground-truth vehicle crash data. As a result of the analysis, it turned out that the index of speeding-risk exposure has a strong explanatory power (R²=0.7) for motorway traffic accidents. This directly indicates that speeding behaviors should be analysed at a microscopic spatiotemporal dimension. Conclusion: The spatial and temporal evolution of vehicle velocity is very variable. It is, hence, expected that the method presented in this study could be efficaciously employed to analyse the causal factors of traffic accidents and the crash risk exposure in microscopic space using mobility trajectory data.

• The Southeast Asian review
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• v.20 no.3
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• pp.183-222
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• 2010

본 연구의 목적은 2008년 후반에 발생한 국제금융위기에 대응하여 조직 개편을 선택한 기업과 그 기업 내의 근로자들 실태 파악을 하는데 있다. 특히 기업구조조정 명목으로 단행된 해고를 모면한 근로자들 (생존자)의 상태를 그들이 지각하는 각 개인의 관리자에 대한 만족도와 그들의 직무관련태도인 직무만족, 조직적 몰입 그리고 이직 의도 간의 관계 관점에서 살피고자 한다. 관리자에 대한 만족도는 근로자들의 직무 관련 태도 변수와 관련되어 사회적 선행변수로 선택되었으며 직무관련태도는 결과변수로 선택하였다. 본 연구를 통해 생존자들의 조직 내 직무관련태도에 관한 이해를 높이는데 필요한 정보를 표출해내어 그들의 실태를 파악하는데 하나의 목적을 두었으며 그들의 관리자와의 사회적 관계가 그들에게 미치는 영향을 파악하는 것이 또 하나의 목적이라 하겠다. 이상과 같은 관계 파악을 통해 얻은 정보로 관련기업이 단기적으로 성공적인 자립을 하여 장기적으로 경쟁력 있는 조직으로 성장할 수 있는 인적자원전략을 제공하는데 2차적인 목적을 두고 있다. 본 연구는 이상과 같은 목적을 달성하고자 그 유의성이 증명된 현존하는 설문을 활용한 조사기법을 채택하여 실증연구를 하였다. 수집한 자료는 SPSS 17.0과 LISREL 8.5을 사용하여 연구모형과 연구의 가설들을 검증하였다. 연구목적을 달성하고자 채택된 가설들은 기존의 문헌연구를 토대로 세워졌다. 연구대상은 태국 북부지역의 대표도시인 치앙마이 내 관광호텔 종사자들로서 외부적으로는 2008년 국제금융위기와 그에 따른 경제침체, 내부적으로는 극심한 정치적 사회적 불안에 의한 관광객의 급감소와 조직의 자구책으로 행해진 조직재구조 차원에서의 해고를 이겨낸 근로자들, 즉 생존자들이었다. 가설검증을 통해 입증된 연구결과에 의하면 1) 근로자들의 관리자에 대한 만족은 그들의 직무만족, 정서적 조직몰입과 지속적 조직몰입에 영향을 미치는 것으로 검증됐다. 2) 근로자들의 관리자에 대한 만족은 그들의 이직의도에는 영향을 미치지 못하는 것으로 검증됐다. 3) 근로자들의 직무만족은 그들의 이직의도에 영향을 미치는 것으로 검증되었다. 4) 근로자들의 조직적 몰입과 이직의도 간의 관계에 있어서는 오직 경제적 성격의 지속적 조직몰입만 영향을 미치는 것으로 검증되었다. 이러한 연구 결과는 기존의 타 연구 결과와 기본적인 맥락은 같게 나왔으나 근로자들의 정서적인 면의 부재는 2008년 후반 당시의 독특한 태국의 사회적, 경제적 그리고 문화적 실태를 보여주는 것이 아닌 가 사료된다. 특히 근로자들이 그들의 직장과의 관계와 관련된 의사결정을 가치가 아닌 경제적인 요소에 의존한다는 결과 그리고 상관인 관리자가 이러한 태도에 전혀 영향력을 미치지 못한다는 결과는 전통적으로 감성적이며 집단주의적인 동양적 문화가 지배하리라고 예상했던 태국에서는 이례적인 결과였다. 그러나 관리자들이 그들의 직무만족 그리고 조직적 몰입에 영향을 주며 직무만족이 이직 의도에 영향을 미친다는 결과와 지속적 조직몰입이 이직의도에 영향을 미친다는 결과는 장기적으로 적극적인 관리자 교육을 통해 근로자들을 조직에 정서적으로도 올바르게 안착시키고 긍정적인 구성원으로 존재하면서 조직에 기여할 수 있는 그들의 역할을 기대할 수 있다고 볼 수도 있다. 이 점은 매우 중요한데 그 이유는 해고를 이겨낸 근로자들은 그 조직이 미래를 짊어지는 마지막 기대변수이기 때문이다.

• Journal of the Society of Disaster Information
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• v.19 no.1
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• pp.161-172
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• 2023

Safety education delivered to construction workers in a lecture manner has limitations in concentration and immersion, so delivery power and interest are low. In order to improve unstable behavior through education and prevent safety accidents, it is necessary to change the paradigm to hands-on education. Purpose: Experiential safety education aims to contribute to preventing accidents for construction workers by quickly recognizing risks, improving emergency response skills, and verifying the effectiveness of pre- and post-learning. Method: Based on a survey of workers who experienced the same work environment as the actual construction site, an opinion survey on the pre- and post-safety experience education and a variable measurement tool were planned, and a research hypothesis was established. Results: The Bayesian theory and MC simulation analysis were used to analyze the structural equation model, and the change in construction worker behavior was confirmed through the intended safety (A), non-experiential education in the sub-area of anxiety (B), average, standard deviation, and minimum and maximum values. Conclusion: The effect of education and industrial accidents are reduced only when construction workers are motivated to participate.

• Journal of the Korean Geotechnical Society
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• v.23 no.6
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• pp.97-102
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• 2007

Though the stability analysis of soil slopes widely employs the limit equilibrium method, the study on the jointed rock slopes must consider the direction of joint and the characteristics of Joint at the same time. This study analyzes the result of the change in the factors which show the characteristics of discontinuity and the shape factor of rock slopes, and so on, in an attempt to validate the propriety as to the interpretation of jointed rock slope stability which uses the general finite element program. First, the difference depending on the flow rules was compared, and the factor effect study was conducted. The selected independent variables included the direction of joint which displays the mechanical characteristics of discontinuity, adhesive cohesion, friction angle, the inclination and height of rock slope which reveal the shape of slope and surcharge load. And the horizontal displacement was numerically interpreted at the 1/3 point below the slope, a dependent variable, to compare the relative degree of factor effects. The findings of study on factor effects led to the validation that the result of horizontal displacement for each factor satisfied various engineering characteristics, making it possible to be applied to stability interpretation of jointed rock slope. A modelling is possible, which considers the application of the result of real geotechnical surveys & laboratory studies and the non-linear characteristics when designing the rock slope. In addition, the stress change which may result from the natural disaster, such as precipitation, and the construction, can be expressed. Furthermore, as the complicated rock condition and the ground supporting effect can be considered through FEM, it is considered to be very useful in making an engineering decision on the cut-slope, reinforcement and so on.

• Journal of Technology Innovation
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• v.19 no.1
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• pp.79-109
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• 2011

In his highly cited book, Innovator's Dilemma (1997), Christensen introduced a notion of disruptive technology that is based on the observations from disk-drive industry and used it as an explanatory variable through which new entrants outperform incumbents in the industry. In explaining his later observations of disruptive innovations in other industries, however, his early theory based on disruptive technology has been applied to all cases without careful distinction between the notions of technology and business model (Markides, 2006). Furthermore, it has been criticized that his model suffers from lack of enough explanatory power and other important factors that are necessary to fully explain the observed phenomena in various cases (Danneels, 2004). Motivated by the critics in literature, the current study carefully distinguishes between innovation of technology and innovation of business model in the process of disruptive innovation, and apply our framework to the case of internet shopping mall business. Our study yields two main results. First, the internet-related business model which Christensen argued as an example of disruptive innovation is accomplished through two distinctive and separable growth phases: a period of technology growth and a period of business model growth. Second, in the process of disruptive innovation, the notion of enabling technology plays an important bridging role that connects core technology and business model. Furthermore, we confirm that the success of business model innovation depends on the degree of maturity of the enabling technologies. In conclusion, Christensen's notion of disruptive innovation can be further detailed in terms of technology innovation and business model innovation, and if there exist enabling technologies, the chance of success of the business model is higher when the enabling technology is matured rather than when the core technology is merely acknowledged as a disruptive technology.

• Journal of Distribution Science
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• v.9 no.2
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• pp.31-36
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• 2011

I conducted empirical analyses of what happens when an offline channel expands to an online channel and whether the pre-existing offline channel's competitive assets (e.g. brand reputation and level of service satisfaction) can be linked to online channel preference. I found that an offline channel's brand reputation and level of service satisfaction can have a direct influence on offline channel preference and a second-hand influence on online channel preference. Thus, if the competitiveness of the online channel is strong enough and its customers have a higher preference for the offline channel, they will be committed and loyal to the company. The resultant enhanced competitiveness of the offline channel will present opportunities for both present and future success. The main results are the following. First, the management of the distribution channel service quality is more important than that of the brand reputation. Customers' experiences of service and subjective evaluations are not important only as the leading factors in the long-term brand reputation management but also as influential factors in channel preference. SoThus, given that the service quality of the pre-existing channel is not the customers' main concern, a strategy of improving the level of service satisfaction aimed at present customers is more valuable than a wide brand positioning strategy aimed at general and new customers. Second, when an offline channel company establishes an internet shopping mall on an online channel, it is highly likely that the preference and subjective evaluation of the present customers will influence the online channel. This applies not only to the special case of an expansion from an offline intermediary channel to an online one, but also to an online channel acting as an expansion of the business model of a conventional manufacturing or service company: both cases are vertical integrations of marketing channels in an expansion of the distribution channel. My theory applies to a wide range of contexts. Third and finally, any business strategy can grasp the meaning of 'channel expansion. Fundamentally, it is an expansion of the sales activity channel and marketing activity. However, it is also a way of enhancing marketing and sales competitiveness through an expansion to an online or offline channel. The expansion of an offline company to an online channel could be seen not as improvement but as an innovation of the business process by which two goals are achieved with one technique. The former is expected to increase the sales of the offline company, and the latter is also expected to increase sales while also contributing to cost reduction.

• Clinical and Experimental Pediatrics
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• v.50 no.8
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• pp.740-745
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• 2007

Purpose : There is a dominant opinion that in vitro fertilization (IVF) leads to an increased incidence of twins, low birth weight (LBW) infants, prematurity and mortality. On the other hand, technical development of IVF and improvement of neonatal intensive care have increased the survival rate of neonates. The purpose of this study was to verify the tendency by comparing the clinical aspects of IVF and spontaneously conceived twins, and to establish methods to increase the survival rate of neonates after IVF. Methods : Retrospective reviews were performed on all twin infants who were admitted to the nursery and NICU at Kangnam Sacred Heart Hospital, Hallym University from January 1, 2000 to December 31, 2006. Medical records of IVF twins (study group, n=92) and spontaneously conceived twins (control group, n=265) were analyzed and compared. Neonatal outcomes and complications, as well as obstetric outcomes, were analyzed and compared. Results : Mean gestational age and birth weight of the study group ($34.6{\pm}3.5$ weeks, $2,203.9{\pm}617.2g$) were considerably lower than those of the control group ($36.3{\pm}2.4$ weeks, $2,367.0{\pm}517.9g$). The frequency of prematurity less than 37 weeks (68.5% vs 51.3%) and extremely LBW (15.2% vs 6.4%) were also significantly higher in the study group. Other neonatal outcomes were all insignificant. The obstetric characteristics, maternal age ($32.6{\pm}3.3$ years vs $30.3{\pm}3.9$ years) and the frequency of cesarean delivery(95.7% vs 79.9%) were significantly higher in the study group. Other obstetric outcomes were insignificant except for the frequency of incompetent internal os of cervix (36.2% vs 3.6%) and cerclage operation (38.3% vs 4.3%). Conclusion : Based on the above results, clinical outcomes of twin infants will be further improved by careful attention and thorough antenatal care of the IVF twins.

• The Journal of the Convergence on Culture Technology
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• v.6 no.2
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• pp.99-106
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• 2020

Changam, Lee Samman(1770~1845), who created his own handwriiting to be referred to as the three great writers of the late Joseon Dynasty, invented as the original 'Haengunyusu Typeface' and developed Calligraphy spirit of DonggugJinche in Honam province. He ultimately pursued the state of tonglyeong by raising the personality of 'writing is the person's personality' and the attitude of learning the old. Through the book chang-amseogyeol, he basically polished Haeseo of Han Dynasty and Wi Dynasty and emphasized that Haengseo and Choseo are done automatically when muscle strength and bone strength are established. And since calligraphy originated from 'nature', it goes through the 'Beobcheongwijin' spirit. After doing so, expressed the state of tonglyeong of " mubeob-ibeob ", the stage of reaching. In addition, Changam showed the aesthetic that you can get the novelty by pursuing the philosophy of 'Wu' and the 'beauty of Stupid and Lacking' based on LaoTzu and ChuangTzu. This is a philosophy that follows nature's logic to reveal nature's nature. And it is an aesthetic that protects his 'True Wu' without knowing and greedy. On the other hand, Changam promoted natural and vital beauty through force in the method of using the brush. He suggested the 'Push and Hard' of the Han dynasty, pushing it with force using this power properly. In particular, the feeling of an IlunMujeog brush in 『Changam Calligraphy-The cloud stays Poem』 overflows with the vitality and bizarre and strange dynamism of the spirit and typeface as eum-yang harmonizes with each other. In addition, the beauty of Push and Hard containing polyeoghamse is misaligned, but it has achieved a natural aesthetic without invading. This work demonstrates the real look of Changam choseo. In addition, the beauty of Push and Hard containing polyeoghamse is misaligned, but it has achieved a natural aesthetic without invading. Changam proves the real look of "Haedong's best Chose Maestro".