• 한국경영과학회지
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• 제34권3호
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• pp.43-53
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• 2009

The pallet loading problem(PLP) requires the best orthogonal layout that loads the maximum number of identical boxes(small rectangle) onto a pallet(large rectangle). Since the high pallet utilization saves the distribution and storage costs, many heuristic and exact algorithms have been developed so far. Martins and Dell have found the optimal layouts for the all PLPs less than or equal to 100 boxes except for only 5 problems in their recent research. This paper defines the 'stair structure' and proposes a new exact algorithm applying it. In order to show the priority of the proposed algorithm, computational results are compared to previous algorithms and the optimal layouts for the S unsolved problems are given.

• 로봇학회논문지
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• 제4권4호
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• pp.265-272
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• 2009

IVarious driving mechanisms to adapt to uneven environment have been developed for many urban search and rescue (USAR) missions. A tracked mechanism has been widely used to maintain the stability of robot's pose and to produce large traction force on uneven terrain in this research area. However, it has a drawback of low energy efficiency due to friction force when rotating. Moreover, single tracked mechanism can be in trouble when the body gets caught with high projections, so the track doesn't contact on the ground. A transformable tracked mechanism is proposed to solve these problems. The mechanism is designed with several articulations surrounded by tracks, used to generate an attack angle when the robot comes near obstacles. The stair climbing ability of proposed robot was analyzed since stairs are one of the most difficult obstacles in USAR mission. Stair climbing process is divided into four separate static analysis phases. Design parameters are optimized according to geometric limitations from the static analysis. The proposed mechanism was produced from optimized design parameters, and demonstrated in artificially constructed uneven environment and the actual stairway.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.104.3-104
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• 2002

A quadruped stair robot introduced here plays a role in monitoring and moving some place where an operator can not reach or when he may not keep watching. It has several features that travels and poses variable position by four caterpillars and quadruped typed arms, transmits an image and command data via RF wireless and network communication. The robot can balance itself when it moves up and down on a slope by using the quadruped mechanism. The robot vision scans ahead before it moves, and the captured image is transferred to a main computer via a RF image module. The main computer analyzes the obstacle, and when it is found the obstacle, the robot avoids from the obstacle and keep moving f...

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.45-48
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• 2001

SL(Stereolithogrphy) part is made by piling up thin layers which causes the stair stepping effect at the surface of SL parts. This effect causes excessive surface roughness and requires additional postprocess finishing such as abrasive basting which is detrimental to part geometry and time consuming. Hence paraffin coating and grinding postprocess is proposed to raise the surface quality of SL part. The paraffin which has suitable properties for the proposed postprocess is coated all over the part surface. By grinding the thin layer of coated on the SL part only, the surface roughness can be improved without any damage on the part. From the experimental result, It is verified as very practical for die casting with silicon rubber mold.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.143-146
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• 1999

The traditional FDTD method in the stair case, the CP-FDTD method, the modified CP-FDTD method, and Dey method have been developed to analyze smooth-curved- surface structures. These methods have some disadvantages such as inaccuracy of the stair-case FDTD, instability of the modified CP-FDTD, and complexity of Dey method. The improved algorithm presented here is a mixed-form of the modified CP algorithm and Dey algorithm. It is to avoid collinear borrowing approximations and to manipulate field update equations. All of preceding methods are applied to the E-plane sectoral horn antenna to get far-field patterns. The validity and applicability of the presented one is to be shown by comparing computed far-field patterns with measured values.

• The Journal of Korean Physical Therapy
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• 제22권6호
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• pp.21-28
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• 2010

Purpose: The purpose of this study was to investigate the kinematic adaptation of head and trunk to ascend stairs and a ramp. Subjects were healthy young adults. Three-dimensional kinematic patterns of head and trunk movements were examined during stair climbing and steeper ramp climbing. Methods: Fourteen young subjects with no history of chronic or acute musculoskeletal, cardiovascular or respiratory disorders took part in this experiment. Kinematic data were collected using a 6 camera Vicon system (Oxford Metrix, Oxford, England). Repeated measures ANOVA analyses were used to investigate the effect of gait mode on kinematics of the head and trunk. Results: The angle of the trunk while ascending stairs or a ramp was modified in three human planes (p<0.05). The angle of head and neck during the ascending of stairs or a ramp was not changed in the sagittal plane but was changed in the frontal and transverse planes (p<0.05). Conclusion: This study describes and discusses some basic kinematic mechanisms underlying the pattern of head and trunk changes during stair and ramp climbing and showed that postural adaptation of the head and trunk is necessary to maintain balance.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.21-28
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• 2006

In the present study, the analysis on heat and fluid flow in subway station platform is carried out by considering the pressure drop between screen doors and stair passages. To investigate the effect on the characteristics of heat and fluid flow of pressure drop, Numerical simulation is applied. The present results show a better cooling condition, in the case of without pressure drop.

• 한국컴퓨터정보학회논문지
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• 제24권1호
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• pp.159-166
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• 2019

Recently, the advanced development of smart devices has increased the interest in health-care, and many people are paying more attentions to disease prevention than disease treatment. Among these prevention methods, the bare body movement has received much attention, and especially walking exercise is attracting much attention because it is enjoyable without any restrictions on place and time. Walking exercise is generally divided into two types: walking on the ground and climbing the stairs. Walking up the stairs consumes much more calories compared to walking on the ground. These walking exercises have the advantage that they can be easily performed by male and female without special equipments or economic considerations. However, there is a lack of applications and systems that accurately determine such walking and stair walking and measure momentum according to stair walking. In this paper, we designed and implemented a real-time walking status analysis system using smartwatch's, pedometer, smartphone's barometer and beacons.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 가을학술발표대회논문집
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• pp.103-104
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• 2023

The purpose of this study is to specify an erection process for each member of the PC staircase. For this purpose, field work was investigated at the LH PC apartment building site and classified in detail through unit work analysis inspection. The results of this study are intended to be used as basic data for creating work sequences and related guidelines for LH's PC staircase.

• 한국전문물리치료학회지
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• 제13권3호
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• pp.10-17
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• 2006

The purpose of this study was to determine the consequence of resistance strengthening exercise on the hip flexor and extensor performed to improve functional mobility in stroke patients more than six months post stroke. Seventeen patients were randomized into two groups. Both groups received conventional physical therapy for six weeks. In addition, the experimental group performed eccentric resistance strengthening exercise in the hip flexor and extensor using an isokinetic dynamometer. The hip flexor and extensor strength, stair up and down mobility, timed get up and go (TUG), 10 m gait velocity, and functional reach were repeatedly measured at baseline, three weeks, and six weeks after treatment. The results were as follows: 1. The experimental group improved more remarkably in the hip flexor and extensor strength, stair up and down mobility, and the 10 m gait velocity after three weeks and six weeks of treatment (p<.05), 2. The control group improved significantly in the hip flexor and extensor strength, and 10 m gait velocity after three weeks of treatment (p<.05), 3. At each three and six week point, the experimental group made greater gains in hip flexor and extensor strength, stair up and down mobility, and 10 m gait velocity than the control group (p<.05). In conclusion, it is desirable to perform resistance strengthening exercises combined with conventional physical therapy to improve functional mobility in chronic stroke patients.