• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1036-1044
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• 2015

This paper estimates the relative risk aversion coefficients of apple farmers. Two hypothetical situations are designed and two-stage questionnaires are conducted for each situation. A utility function that has constant relative risk aversion was used, and it was assumed that the relative risk aversion coefficients follow a log-normal distribution. To reduce the hypothetical bias, the data was collected from repetitive questions. As a result, the mean and standard deviation of the relative risk aversion coefficients of apple farmers was 10.915 and 7.516, respectively. The relative risk aversion coefficients conditional on a survey response in each category were also measured. These findings can be used as parameters to analyze the effects of risk management tools.

• Information Systems Review
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• v.23 no.4
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• pp.165-182
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• 2021

In nowadays, Covid-19 has transformed patterns of consumers' behavior into a non-face-to-face mode. As the patterns of consumption have been digitalized, it has become a daily routine for consumers who perform so-called shadow work, which involves unpaid jobs that they have to do by themselves. In mobile grocery service context, consumers' shadow work could lead to shopping avoidance as well as switching toward other shopping channels. Thus, this study is to examine how consumers' perception of shadow work affect mobile shopping avoidance and switching intention toward other shopping channels. This study collected 283 survey data from online respondents who have experience on subscription services for ordering groceries in online. We also tested our research model by using partial least squares. Based on our results, this study has found that the perception of shadow work had a positive effect on mobile shopping avoidance as well as switching intention. We expect that our findings could contribute to relevant research on shadow work and suggest practical implications for digital platforms dealing with subscription business models

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.1
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• pp.10-17
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• 2018

To prepare the integrated safety management system 'e-navigation', research is being conducted on the route exchange for sharing intended routes between ship and ship, and between ship and land. But they don't have enough specific grounds for the effects of route exchange and the necessity of its introduction and focus on technical aspects like the implementation of route exchange. This study tried to quantitatively analyze the effects of route exchange on sailing safety with the use of ship handling simulation, integrate simulation performers' subjective evaluations, and investigate the effects of route exchange. The ship-to-ship route exchange resulted in the initial collision avoidance action time was 3.43 minutes faster, the collision avoidance direction change rate was 60 %, the proximity to target A was 31 %, and Mean Rudder Angle Index decreased by 57 %. In addition, 95 % of the survey respondents had an effect on the decision making of collision avoidance, 85 % had a positive impact on safety navigation, 90 % had an accident prevention effect, 70 % reduced the psychological burden of officers, and 70 % should be introduced in practice.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2009.05a
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• pp.88-92
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• 2009

본 논문에서는 시선인식을 이용한 지능형 휠체어 시스템에 대해 설명한다. 지능형 휠체어는 초음파센서를 이용하여 전동휠체어가 장애물을 감지하여 회피할 수 있게 하고, 조이스틱을 움직이기 힘든 중증 장애인을 위해 시선인식 및 추적을 이용하여 전동휠체어를 움직일 수 있게 하는 인터페이스를 제안한다. 지능형 휠체어는 시선인식 및 추적 모듈, 사용자 인터페이스, 장애물 회피 모듈, 모터 제어 모듈, 초음파 센서 모듈로 구성된다. 시선인식 및 추적 모듈은 적외선 카메라와 두개의 광원으로 사용자 눈의 각막 표면에 두 개의 반사점을 생성하고, 중심점을 구한 뒤, 동공의 중심점과 두 반사점의 중심을 이용하여 시선 추적을 한다. 시선이 응시하는 곳의 명령어를 사용자 인터페이스를 통해서 하달 받고, 모터 제어 모듈은 하달된 명령과 센서들에 의해 반환된 장애물과의 거리 정보로 모터제어보드에 연결되어 있는 두 개의 좌우 모터들을 조종한다. 센서 모듈은 전등휠체어가 움직이는 동안에 주기적으로 센서들로부터 거리 값을 반환 받아 벽 또는 장애물을 감지하여 장애물 회피 모듈에 의해 장애물을 우회 하도록 움직인다. 제안된 방법의 인터페이스는 실험을 통해 시선을 이용하여 지능형 휠체어에 명령을 하달하고 지능형 휠체어가 임의로 설치된 장애물을 효과적으로 감지하고 보다 정확하게 장애물을 회피 할 수 있음을 보였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.9
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• pp.1718-1726
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• 2006

In this paper, we proposed a fuzzy controller and algorithm for efficiently obstacle avoidance in unknown space. The ultrasonic sensor is used for position and distance recognition of obstacle, and fuzzy controller is used for left and right wheels angular velocity control. The fuzzification is used singleton method and the control rule is each wheel forty-nine. The fuzzy inference is used simplified Mamdani's reasoning and defuzzification is used SCOG(Simplified Center Of Gravity). The computer simulation based on mobile robot modelling was performed for the capacity of fuzzy controller and the really applicable possibility revaluation of the proposed avoidance algorithm and fuzzy controller. As a result, mobile robot was exactly reached in target and it avoided obstacle efficiently.

• Korean Journal of Head & Neck Oncology
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• v.33 no.1
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• pp.1-5
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• 2017

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer globally with high morbidity and mortality. Immune surveillance is well recognized as an important mechanism to prevent development or progression of HNSCC. HNSCC can escape the immune system through multiple mechanisms including development of tolerance in T cells and inhibition of T-cell-related pathways, generally referred to as checkpoint inhibitors. Recent clinical trials have demonstrated a clear advantage in advanced HNSCC patients treated with immune checkpoint blockade. Right at the front of the new era of immunotherapy, we will review current knowledge of immune escape mechanisms and clinical implication for HNSCC.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.9
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• pp.1795-1802
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• 2009

Motion based serious game is a new style of game and exercise using hands, arms, head and whole body. At that time gamer's reachable movement space is an important game space and interaction happening place. We propose efficient game spatial division and analysis algorithm that gives special information for collision avoidance of game objects. We devide into 9 parts of game space and check the enemy position and upper, down, left and right side movement information of gamer and calculate optimal path for collide avoidance of the enemy. To evaluate the method, we implemented a motion base serious game that consists of a web cam, a player, an enemy, and we obtained some valid results of our method for the collision avoidance. The resole demonstrated that the proposed approach is robust. If movement information is in front of enemy, then the enemy waits and finds the place and runs to avoid collision. This algorithm can be used basic development of level control and effective interaction method for motion based serious game.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1992.05a
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• pp.43-43
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• 1992

최근 수년 전부터 학습(learning), 기억(memory)의 분자약리학적 기전과 치매(dementia)의 신경생리학적 원인 규명에 대한 연구가 사회적 요구에 부응하여 증가하고 있다. 이에 본 연구에서는 횐쥐를 이용하여 실험실적 건망모델을 설정하여 항치매 물질의 효력 screening을 시도하였다. 실험실적 건망모델은 다음 두 가지 방법으로 설정하였다. 첫째, Acetylcholine 길항제인 Scopolamine을 사용하여 중추신경계중 기억, 학습기전과 관련된 것으로 알려진 cholinergic신경계률 차단하여 유발한 실험적 건망모델과, 둘째, 단백질합성 저해제인 cycloheximide를 사용하여 기억, 학습경로에 관여하는 수종의 중추 단백질듈을 비선택적으로 저해하여 유발한 실험적 건망모델을 이용하여 인삼, 오미자등의 항치매 효과를 검색하고자 수동적 회피학습능, 능동적 회피학습능, 자발운동량을 측정하여 기억, 학습, 행동의 상관 관계를 고찰하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.535-537
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• 2010

군집로봇은 어떤 작업을 수행하기 위해 여러 로봇이 함께 움직이게 된다. 이렇게 여러 로봇이 함께 작업을 수행하다 보면 로봇 간의 충돌을 피해야 할 경우가 발생한다. 각 로봇은 주어진 환경을 인식하고 모델링하며 로봇들 간에 충돌을 피하여 주어진 임무를 효과적으로 이행할 수 있게 하는 것이 이 연구의 핵심이다. 로봇 간 충돌을 효과적으로 해결하기 위해 충돌 전 다양한 위치와 다양한 방법으로 충돌을 피할 수 있도록 했다. 따라서 이 논문에서는 카메라 센서와 위치정보 통신을 이용한 방법을 통해 군집로봇간의 충돌 회피에 대해 연구하였다.

• Science of Emotion and Sensibility
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• v.17 no.4
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• pp.29-40
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• 2014

The positive relationship between older driver's mobility and life satisfaction is well established(e. g., Collins, 2008). The present study showed that this relationship can be changed by older drivers' motivation, aspects of mobility, and affectivity. Specifically, this study examined whether aspects of mobility(amount of driving measured by travel distance and time: 'AD' or amount of driving for social activity: 'DSA') can be differed as a function of approach/avoidance motivation(measured by BIS/BAS scale, Carver et al., 1994) and positive/negative affect(PA/NA; measured by SPANAS, Diener et al., 2009) mediate the relationship between the aspects of mobility and life satisfaction(measured by SWLS, Diener et al., 1985). Self-reported scores of the variables of 132 older drivers(ages of over 65) were analyzed using correlation analysis and path analysis. The results can be summarized as followings. First, the older driver's BAS was found to be positively related to DSA, but BIS was negatively to AD. In particular, DSA positively mediated the relationship between BAS and PA. Second, PA, in turn, positively mediated the relationship between DSA and life satisfaction. The results can provide useful insights to understand the relationship between older driver's driving property, motivation, affectivity and life satisfaction.