• 교육녹색환경연구
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• 제11권2호
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• pp.51-60
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• 2012

This research aims to take a close look at the following topics; the ground elevation of playground, equipments of playground, and equipments around playground, and to propose the improvement measure for favorable educational environment. In consideration of the needs mentioned, the following improvement measure for playground can be suggested. First, the elevation of playground should be changed. According to Environment psychology, current playground elevation should be lowered 2 stair-long height from a classroom site. This kind of elevation change can remove unnecessary stairs, and reduces inconvenience incurred by stairs and edges, which results in considerable educational finance saving. Second, the incidental equipment within a playground needs to be improved. This fact is found out at the surveyed schools; school gathering is held at classrooms (through broadcasting) or a multi-purpose auditorium in place of a playground. The results of this study make us conclude that the most important issue to be considered in the processes of selection and investigation for school playground elevation, incidental equipments and others.

• 제어로봇시스템학회논문지
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• 제20권10호
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• pp.1067-1072
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• 2014

The ability to overcome obstacles is necessary for field robots for various applications including the ability to climb stairs. While much research has been performed focusing on overcoming obstacles, the resulting robots do not have sufficient ability to overcome obstacles such as stairs. In this research, the purpose is to overcome relatively large obstacles by flipping locomotion through the modification of the stair climbing robotic platform of the previous research. We propose two scenarios to overcome large obstacles: a rear wheel driving system and an elevation system using a ball screw. The research is performed based on static analyses on obstacle-climbing. As the simulation results indicate, we determined the optimal posture of the robot for climbing obstacles for rear wheel driving. Also, an elevation system is analyzed for obstacle climbing. Between the two scenarios an elevation system is determined to reduce the operating torque of the actuator, and the prototype was recently assembled. The climbing ability of the robotic platform is verified. We expect the application area for this robotic platform will be in accident areas of nuclear power plants.

• 대한의용생체공학회:의공학회지
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• 제32권2호
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• pp.93-104
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• 2011

The purpose of this study was to investigate lower-limb joint torque of the two groups as it changed by somatosensory stimulation during the descent down three stairs of different heights and to describe the difference between the two groups, which are young people group and elderly people group. Subjects of each groups climbed down a stair at four stimulation conditions, which are non-stimulation, tibialis anterior tendon stimulation, achilles tendon stimulation, tibialis anterior - achilles tendon stimulation. Motion capture data were collected using 3D optoelectric motion tracking system that utilizes active infrared LEDs, near infrared sensor and force plate. The obtained motion capture data was used to build 3D computer simulation model. The results show that lower-limb joint torque of the two groups changed with somatosensory stimulation as they descended the stairs and the joint torque of the two groups differed from each other.

• 토지주택연구
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• 제2권4호
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• pp.509-516
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• 2011

프리캐스트 콘크리트는 현장작업을 최소화하고 공사품질을 보장할 수 있으며 공사기간을 단축시킬 수 있는 장점을 갖고 있다. 특히 계단실의 경우 재래식 거푸집을 사용할 경우 골조공사의 품질저하와 다수의 인력투입에 따른 생산성의 저하 및 시공의 어려움 등의 문제점이 있다. 본 연구에서는 PC 계단 접합부 상세를 개발하고, 제안한 접합부의 일체성확보와 사용성 및 안전성을 검증하기 위해 구조성능실험을 수행하였으며, 단순 핀접합 실험체에 비해 구속도의 증가, 내력, 강성 및 연성의 증가를 확인할 수 있었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.598-603
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• 2005

Recently, the advanced industries using micro parts are rapidly growing. The appearance of ultra-precision feed mechanism and the development of control system make it possible to process parts in sub millimeter scale by mechanical methods. Micro endmilling is one of the prominent technology that has wide spectrum of application field ranging from macro parts to micro products. So, micro stairs have been trying to cut by using high revolution air turbine spindle and micro-endmill, and studying for magnitude of cutting force. This investigation deals removal characteristics of burr generated by micro endmilling process. Also, decreasing of burr is significant problem in making smooth and precise parts in micro endmilling. In micro endmilling, the material removal rate(MRR) and cutting forces are very small. This paper presents an investigation on the machining characteristics for micro stairs by using ultrahigh-speed air turbine spindle in machining.

• 반도체디스플레이기술학회지
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• 제21권4호
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• pp.121-125
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• 2022

This paper deals with the development of a deep-learning-based robot that recognizes various types of stairs and performs a mission to go up to the target floor. The overall motion sequence of the robot is performed based on the ROS robot operating system, and it is possible to detect the shape of the stairs required to implement the motion sequence through rapid object recognition through YOLOv4 and Cuda acceleration calculations. Using the ROS operating system installed in Jetson Nano, a system was built to support communication between Arduino DUE and OpenCM 9.04 with heterogeneous hardware and to control the movement of the robot by aligning the received sensors and data. In addition, the web server for robot control was manufactured as ROS web server, and flow chart and basic ROS communication were designed to enable control through computer and smartphone through message passing.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.863-870
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• 2022

Unsatisfactory urban walking environment stresses urban residents, and may cause mental illness and chronic diseases by reducing walking activities. Therefore, establishing a high-quality walking environment that can promote walking activities in urban residents has emerged as an important issue. The walking environment consists of various components, such as trees, stairs, streetlights, benches, signs, fences, and facilities, and it is essential to understand which components and their settings act as satisfiers or dissatisfiers for pedestrians, to create a better quality walking environment. Therefore, this study investigated pedestrian satisfaction and dissatisfaction as a function of various environmental components through a survey using walking environment images. The results revealed that most of the walking environment components except the braille block and treezone exhibited significant correlations with pedestrian satisfaction. Particularly, safety-related component (e.g., adjacent roads, parked cars, traffic cushions, and car separation), and landscape-related components (e.g., trees and green), as well as the material settings of landscape facilities (e.g., wooden fences, benches, stairs, and walkway surfaces) correlated with pedestrian satisfaction. The results of this study can contribute to the extraction of useful features to evaluate pedestrian satisfaction as a function of the walking environment. The research outcome is expected to assist in the effective arrangement of walking environment components and their settings, which will ultimately contribute to significantly satisfactory walking environment and encourage walking activities.

• 로봇학회논문지
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• 제19권2호
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• pp.149-158
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• 2024

This paper presents a robust autonomous navigation and reconnaissance system for tracked robots, designed to handle complex multi-floor indoor environments with stairs. We introduce a localization algorithm that adjusts scan matching parameters to robustly estimate positions and create maps in environments with scarce features, such as narrow rooms and staircases. Our system also features a path planning algorithm that calculates distance costs from surrounding obstacles, integrated with a specialized PID controller tuned to the robot's differential kinematics for collision-free navigation in confined spaces. The perception module leverages multi-image fusion and camera-LiDAR fusion to accurately detect and map the 3D positions of objects around the robot in real time. Through practical tests in real settings, we have verified that our system performs reliably. Based on this reliability, we expect that our research team's autonomous reconnaissance system will be practically utilized in actual disaster situations and environments that are difficult for humans to access, thereby making a significant contribution.

• 한국전문물리치료학회지
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• 제20권1호
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• pp.18-27
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• 2013

The purpose of this study was to compare the ring lock type knee-ankle-foot orthosis (KAFO) with newly developed 4-bar linkage KAFO on the gait characteristics of persons with poliomyelitis clinically. This 4-bar linkage is the stance control type KAFO which provide the stability during stance phase and knee flexion during swing phase. Two subjects participated in this study voluntarily. We provided the customized 4-bar linkage KAFO then asked the subjects to walk in level surface and stairs under the two different KAFO conditions. The characteristics of gait in the persons with poliomyelitis were evaluated using a 3D motion analysis system and force plate. Additionally 6 minute walk test for physiological cost index were conducted using pulse oximeter to measure the energy consumption. In the results of this study, the differences of 4-bar linkage KAFO compared with ring lock type KAFO are as follows: (1) Walking speed, stride length, and step length on level increased in subjects, (2) The gait symmetry was improved by generated knee flexion and decreased pelvic external rotation on level and stairs walking, (3) Decreased vertical excursion of center of mass and pelvic elevation during swing phase was decreased on level, (4) Knee extension moment, hip flexion moment, hip and knee internal rotation moment of non-braced limb were decreased on level walking, (5) Walking speed in 6-minute walk test was increased and physiological cost index was decreased. These findings indicate that 4-bar linkage KAFO compared with ring lock type KAFO is effective in enhancing pattern, endurance, and energy consumption in level surface and stairs walking.

• 한국운동역학회지
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• 제25권3호
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• pp.323-333
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• 2015

Objective : The purpose of this study was to investigate the changes of gait patterns and muscle activations with increased loads during stair walking. Also, it can be used as descriptive data about continuous stair walking in a real life setting. Method : Twelve sedentary young male adults(Age: $27.0{\pm}1.8yrs$, Weight: $65.8{\pm}9.9kg$) without any lower extremity injuries participated in this study. Participants performed stair walking up 7 floors and their ascending and descending motion on each floor was analyzed. A wireless electromyography(EMG) were attached on the Rectus Femoris(RF), Biceps Femoris(BF), Gastrocnemius(GN), Tibialis Anterior(TA) muscle to calculate integrated EMG(iEMG), median frequency(MDF) and co-contraction index(CI). Chest and left heel accelerometer signal were recorded by wireless accelerometer and those were used to calculate approximate entropy(ApEn) for analyzing gait pattern. All analyses were performed with SPSS 21.0 and for repeated measured ANOVA and Post-hoc was LSD. Results : During ascending stairs, there were a statistically significant difference in Walking time between 1-2nd and other floors(p=.000), GN iEMG between 2-3th and 6-7th(p=.043) floor, TA MDF between 1-2nd and 5-6th(p=.030), 6-7th(p=.015) floor and TA/GN CI between 2-3th and 6-7th(p=.038) floor and ApEn between 1-2nd and 6-7th(x: p=.003, y: p=.005, z: p=.006) floor. During descending stairs, there were a statistically significant difference in TA iEMG between the 6-5th and 3-2nd(p=.026) floor, and for the ApEn between the 1-2nd and 6-7th(x: p=.037, y: p=.000, z: p=.000) floor. Conclusion : Subjects showed more regular pattern and muscle activation response caused by regularity during ascending stairs. Regularity during the first part of stair-descending could be a sign of adaptation; however, complexity during the second part could be a strategy to decrease the impact.