• 경영과학
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• 제21권1호
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• pp.39-55
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• 2004

Efficient crew scheduling for cockpit crew is important in airline industry due to operational safety and cost associated with the flight duty time. Because of complexity of regulations imposed to the cockpit crew. it is complicated to generate an efficient schedule. Schedule of cockpit crew can be generated through two steps; selecting of flight patterns. and scheduling of them to the specific time horizon. Heuristic method is developed and applied with massive data in a limited time of computation. A set of flight patterns is selected from all possible flight patterns. which are generated by composing the flight leg based on regulations. by using the set partitioning problem with objective function of oversea stay cost. The selected set of flight patterns found at the first step is allocated to 4 week crew schedule to minimize the variance of total fight time assigned to each crew. The crew schedules obtained are evaluated and compared with the ones currently used in one of major airline company.

• 로봇학회논문지
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• 제16권2호
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• pp.155-163
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• 2021

In this paper, we propose a four 2-link robotic leg landing system that is used for leveling the bottom of the landing system, even when the quadcopter posture is changed. The case of conventional skid type landing gear has a risk when the quadcopter lands on a moving vehicle because the skid type landing gear is tilted to the landing site at this situation. To solve this problem, it is necessary to level the bottom of the landing system when the quadcopter posture is changed in the flight. Therefore, the proposed landing system used a four 2-link robotic leg with leveling method. The leveling method was derived from the method of determining a plane. The superiority of the proposed system was verified with 6-axis stewart platform and real flight experiment, and it shows feasibility of leveling method and proposed landing system.

• 로봇학회논문지
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• 제17권4호
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• pp.438-446
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• 2022

In this paper, we propose an intelligent three-legged landing system that can maintain stability and level even on rough terrain than conventional four-legged landing systems. Conventional landing gear has the limitation that it requires flat terrain for landing. The 3-leg landing system proposed in this paper extends the usable range of the legs and reduces the weight, allowing the quadcopter to operate in various environments. To do this, kinematics determine the joint angles and coordinates of the legs of the two-link structure. Based on the angle value of the quadcopter detected via the IMU sensor, the leg control method that corrects the posture is determined. A force sensor attached to the end of the leg is used to detect contact with the ground. At the moment of contact with the ground, landing control starts according to the value of the IMU sensor. The proposed system verifies its reliability in various environments through an indoor landing test stand. Finally, in an outdoor environment, the quadcopter lands on a 20 degree incline and 20 cm rough terrain after flight. This demonstrates the stability and effectiveness of the 3-leg landing system even on rough terrain compared to the 4-leg landing system.

• 한국의류산업학회지
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• 제11권2호
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• pp.286-292
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• 2009

The purpose of this study is to analyze the pattern of the present flight suit, to select variables of human body and key dimensions for making pattern of the flight suit, and to decide the most appropriate size of human body and rate of ease for designing an overall flight suit. For analyzing the pattern of flight suit, we used "M95Special" (men ; chest circumference 92-97 cm ; height : above 177 cm), which was indicated as the standard of the Ministry of National Defense. We analyzed general appearance and the actual dimensions of the pattern of the flight suit. As a result of analyzing the pattern, flight suit was front-opened overall style which had a flat collar with rounded edges, two-pieced sleeves with lower height of the sleeve's cap, 3cm-width belt on the waist and 8 pockets. To decide the most appropriate size of human body, we selected 20 variables of human body in the 359 variables of the Size Korea by referring the previous studies. The 20 variables of human body were 9 circumferences (chest, waist, hip, neck, armscye, wrist, thigh, knee, and ankle), 9 lengths (stature, back interscye fold, waist back, crotch height, crotch, body rise, arm, outside leg and total), and 2 breadths (biacromial and chest). We drew out the size of 20 variables from the Size Korea and US Army anthropometry data and decided the most appropriate values from the drawn data for applying to the pattern of flight suit.

• 한국운동역학회지
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• 제16권4호
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• pp.115-124
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• 2006

This study was conducted to investigate the running motion in the max-velocity phase(150-160m) and the fatigue phase(350-360m) during 400m sprint by performed elementary school athletes. Eighteen elementary school male athletes who achieved at least the 3rd place in the sprint at the Korea Gangwon-Do elementary school track and field meetings during 2004 and 2005 were selected as subjects. The running motions performed by the subjects were recorded using two 8mm high speed cameras at the nominal speed of 100 frames per second. The Direct Linear Transformation technique was adopted from the beginning of filming to the final stage of data extraction. KWON 3D motion analysis package program was used to compute the 3 Dimensional coordinates, smoothing factor in which lowpass filtering method was used and cutoff frequency was 6.0 Hz. The movement patterns during foot touchdown and takeoff for the running stride were related with the biomechanical consideration. Within the limitations of this study it is concluded: In order to increase running velocity, several conditions must be fullfilled at the instant of leg touchdown and takeoff during the fatigue phase(350-360m). First, the body C.O.G(Center of Gravity) height should be raised at the instant of leg touchdown and takeoff during the fatigue phase. Second, the foot contact time should be shortened and the takeoff distance should be increased at the foot takeoff during the fatigue phase. Third, the shank angular velocity with respect to a transverse axis through the center of gravity should be increased during the leg touchdown and takeoff in the fatigue phase. Forth, the active landing style described as clawing the ground with the sole of the foot should be performed during the leg touchdown and takeoff in the fatigue phase) phase. Fifth, In order to increase running velocity in the fatigue phase while taking a slightly greater leg knee angle and body lean angle within the range of the subject's running motion during the fatigue phase would result in greater flight distance.

• 한국의류산업학회지
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• 제12권5호
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• pp.633-641
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• 2010

The purpose of this study is to evaluate a new flight suit in bilateral ways; subjectively and objectively in the improvements of comfort and mobility. Seven healthy males at the age of twenties volunteered in this wearing test. They were over 177 cm in height and 92-95 cm in chest circumference, which satisfies the M95 Special' size described in the Korean Military Specifications and Standards. The subjective satisfaction was evaluated according to the criteria of ease of donning and doffing, fitness of wear, mobility, space between cloth and body, convenience in using restroom. Subjective satisfaction evaluation says that the best improvement of movement are neck circumference, chest breadth, armscye circumference, waist back length, crotch length, crotch height and body rise. According to the evaluation, improvements of mobility were conspicuous especially in parts of body like neck, breast, waist, back, and arms. When evaluating objective satisfaction, we measured a angle difference in a prescribed standard-grid on a photograph that picked up while the subject performed each motion in front of 10 cm-interval grid. As a result, the motion that had angle difference above 5 degrees were arm stretching and standing on single leg holding at forward or at his side. Bending necks and waist, crouching also had angle difference of over 5 degrees. The improvements are discussed from the viewpoint that the increased ease in parts of armscye circumference and crotch in new flight suit pattern.

• 한국운동역학회지
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• 제23권1호
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• pp.19-24
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• 2013

The aim of the study was a quantitative analysis of elite athlete's $540^{\circ}$ Dwihuryeochagi and effects of ground movements to the jumping height and kicking velocity. Eleven elite players(Taekwondo demonstration team) participated in this study. In order to get the kinetic and kinematic variables, ten Vicon cameras and a force plate were used. Foot segment velocity(FSV), vertical ground reaction force(GRF), impulse, ground time(GT) in phase 1, trunk angular velocity(TAV), vertical center of gravity(COG), flight time(FT) in phase 2 and kicking leg segment velocity(KSV) in phase 3 were measured and analyzed. Results indicated that there were similar patterns of variables among phases between subjects. Non-significant correlation(r=.145) between flight time(FT) and impulse was found. Also non-significant correlation(r=.119) between center of gravity(COG) and impulse was found. In conclusions, there were similar strategies in phase 1, phase 2, and phase 3 between subjects.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2008년도 추계학술대회 및 정기총회
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• pp.65-75
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• 2008

Over the last three decades, there are many researches focusing on the practice and theory of RM in airlines. Most of them have dealt with a seat assignment problem for maximizing the total revenue. In this study, we focus on a seat assignment problem in airlines. The seat assignment problem can be modeled as a stochastic programming model which is difficulty to solve optimally. However, with some assumptions on the demand distribution functions and a linear approximation technique, we can transform the complex stochastic programming model to a Linear Programming model. Some computational experiments are performed to evaluate out model with randomly generated data. They show that our model has a good performance comparing to existing models, and can be considered as a basis for further studies on improving existing seat assignment models.

• 경영과학
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• 제26권3호
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• pp.117-131
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• 2009

Over the last three decades, there are many researches focusing on the practice and theory of RM in airlines. Most of them have dealt with a seat assignment problem for maximizing the total revenue. In this study, we focus on a seat assignment problem in airlines. The seat assignment problem can be modeled as a stochastic programming model which is difficulty to solve optimally. However, with some assumptions on the demand distribution functions and a linear approximation technique, we can transform the complex stochastic programming model to a Linear Programming model. Some computational experiments are performed to evaluate out model with randomly generated data. They show that our model has a good performance comparing to existing models, and can be considered as a basis for further studies on improving existing seat assignment models.

• 항공우주정책ㆍ법학회지
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• 제32권2호
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• pp.3-31
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• 2017

지난 2017년 10월 12일 영국 고등법원(Royal Courts of Justice)은 항공기 운항지연에 따른 항공사의 보상책임에 관하여 판단하였다. 2건의 사건이 병합된 사안에서 원고인 승객들은 영국 리버풀을 출발하여 아랍에미레이트의 두바이를 경유하여 각각의 목적지인 방콕과 시드니로 가기 위해 피고 항공사와 운송계약을 체결하였다. 사안에서 최종 목적지에 승객이 연착되었는지 여부를 판단함에 있어서 연결편을 포함하는 전체 항공여정이 고려되어야 한다는 원고측의 주장에 대해 피고 항공사는 첫 번째 항공편에 발생한 연착만이 항공사의 책임을 판정하는 고려의 대상이 되어야 한다고 주장하였다. 결국 이러한 다툼은 유럽연합(EU)의 항공소비자 보호에 관한 Regulation (EC) No. 261/2004의 적용범위에 관한 것이었다. 즉, 첫 번째 항공운송은 EU지역의 공항을 이륙한 항공편이었고, 두 번째 항공운송은 EU가 아닌 다른 지역에서 운항되었고 더욱이 해당 운송인이 EU에서 설립된 항공사가 아니므로 환승 이후의 항공운송에 관해서는 Regulation 261의 적용이 배제되므로 규정된 금전보상의무가 인정될 수 없다고 피고 항공사가 주장하였던 것이다. 본 논문은 이와 같이 연결편에 의한 항공운송 계약의 이행에서 발생한 지연에 관한 Regulation 261의 적용범위가 문제되었던 사례와 유럽연합사법법원(Court of Justice of the European Union, CJEU)의 판례를 검토할 목적에서 기술되었다. 해당 사례를 연구하는 것은 우리 국민과 항공사에게 시사하는 바가 적지 않다. 우선 Regulation 261 규정에 따라, EU지역을 출발하는 모든 항공사를 이용하는 승객은 동 규정의 적용대상에 포함되므로 EU를 출발하는 우리 국적사들은 Regulation의 직접 적용을 받게 된다. 비록 지리적인 이유로 유럽을 출발하여 우리나라를 경유해서 타국으로 환승하는 여객이 사안에서 문제가 되었던 중동지역과 비교할 때 절대적으로 많지는 않을 것으로 생각되지만, 해당 규정의 의미와 판례동향은 분명히 참고가 필요할 것으로 본다. 나아가 그 서문에서 천명하고 있는 바와 같이 Regulation 261은 기본적으로 항공운송인 보다 소비자인 여객의 권리보호에 친화적인 판례를 다수 도출하고 있는 바, 우리나라의 항공소비자 보호를 위한 법제연구에도 본 연구는 좋은 참고가 될 수 있을 것으로 본다.