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Study of a Leveling Mobile Platform for Take-off and Landing of Unmanned Aerial Vehicles (무인항공기 이착륙을 위한 수평 유지 이동 플랫폼)

  • Lee, Sangwoong;Kawk, Junyoung;Chu, Baeksuk
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.19 no.4
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    • pp.85-92
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    • 2020
  • Applications for the unmanned aerial vehicle (UAV) have expanded enormously in recent years. Of all its various technologies, the UAV's ability to take off and land in a moving environment is particularly required for military or oceanic usage. In this study, we develop a novel leveling platform that allows the UAV to stably take off and land even on uneven terrains or in moving environments. The leveling platform is composed of an upper pad and a lower mobile base. The upper pad, from which the UAV can take off or land, is designed in the form of a 2 degrees of freedom (DOF) gimbal mechanism that generates the leveling function. The lower mobile base has a four-wheel drive structure that can be operated remotely. We evaluate the developed leveling platform by performing extensive experiments on both the horizontal terrain and the 5-degree ramped terrain, and confirm that the leveling platform successfully maintains the horizontal pose on both terrains. This allows the UAV to stably take off and land in moving environments.

A Verification of the Accuracy in BIM-Based Quantity Taking-Off - Focusing on Finishing Work (BIM 기반 물량 산출의 정확성 검증 - 마감공사 공종을 중심으로)

  • Kim, Ji-Hyun;Yoon, Su-Won
    • Journal of KIBIM
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    • v.3 no.2
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    • pp.1-9
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    • 2013
  • Currently, various studies and applications related BIM based quantity take-off have been attempted, because of the accuracy of cost estimating and reliability by using the BIM model information in automatical calculation. Finishing works that have a large number of various types and materials need the higher accuracy and reliability on the BIM-based quantity take-off. Therefore, this study compared and analyzed 2D and 3D based quantity through Test-bed and determine the cause of the quantity difference. This verified the accuracy and efficiency in the BIM-based quantity take-off for finishing works. Also this study has been proposed opinions for calculating the exact BIM-based quantity take-off.

Residual Vibration Control of High Speed Take-out Robot Used for Handling of Injection Mold Plastic Part (고속운동 플라스틱 금형사출 부품 취출 로봇의 잔류진동 제어)

  • Rhim, Sung-Soo;Park, Joo-Han
    • Journal of the Korean Society for Precision Engineering
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    • v.28 no.9
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    • pp.1025-1031
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    • 2011
  • Take-out robots used for handling of the plastic parts manufactured with the injection mold are usually the gantry type that consists of long and thin links, The performance of the take-out robot is determined by the speed of the motion and the positioning accuracy to grab the part out of the mold, As the speed of the robot increases the flexure in the links of the take-out robot becomes more significant and it results in more residual vibration, The residual vibration deteriorates the positioning accuracy and compels the operator to slow down the motion of the robot. The typical method to reduce the vibration in the robot requires stiffening the links and/or slowing down the robot, Vibration control could achieve the desired performance without increasing the manufacturing cost or the operation cost that would be incurred otherwise, Considering the point-to-point nature of the task to be performed by the take-out robot the time-delay command (or input) shaping filter approach would be the most effective control method to be adopted among a few available control schemes. In this paper a direct adaptive command shaping filter (ACSF) algorithm has been modified and applied to design the optimal command shaping filters for various configuration of the take-out robot. Optimal filters designed by ACSF algorithm have been implemented on a take-out robot and the effectiveness of the designed filters in terms of vibration suppression has been verified for multiple positions of the robot.

Estimation of Cut-off Stratum in the Highly Skewed Population (왜도가 심한 모집단의 절사층 추정)

  • 한근식
    • Survey Research
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    • v.5 no.1
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    • pp.93-101
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    • 2004
  • In business survey, cut-off sampling is usual, The contribution from cut-off part of the population is at least small in comparison with the remaining population. In this case, part of the target population is excluded from the selection and parameter estimations are only based on Take-all and Take-some stratum. It may be tempting not to use resources on enterprises that contribute little to the overall results of the survey. And this reduces the response burden for these small enterprises. But, the size of cut-off stratum has been increased as a way to manage reduced budgets. This leads to additional bias. In this study, the population have been separated as three stratum, cut -off, take-some, take-all, and we will estimate cut-off part using auxiliary variable.

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Estimation of WIGs' Take-off State Based on Planing Theory (활주선의 정상 활주 상태 모델을 이용한 WIG선의 이수 상태 추정)

  • Yeo, Dong-Jin;Yoon, Hyeon-Kyu;Lee, Chang-Min
    • Journal of the Society of Naval Architects of Korea
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    • v.44 no.5
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    • pp.534-541
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    • 2007
  • This paper suggests the mathematical method for the estimation of the required engine output for WIG crafts. The engine size of a WIG craft Is a key parameter in the design stage, because WIGs should overcome the hump drag during the take-off. Therefore, it is very important for a WIG designer to estimate required power and state change during take-off. The mathematical method was developed based on the steady planing state model of a planing boat. Through numerical calculations on various take-off states, it was found that the suggested method could give reasonable estimation of required power and state change during take-off.

Analysis of Oppositive Interaction between Cd and Zn Toxicity in Coastal Algae (연안 조류에서 Cd와 Zn 독성의 반대 작용 분석)

  • 이봉헌;김정호;정성옥;김성미;박흥재
    • Journal of Environmental Science International
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    • v.11 no.10
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    • pp.1069-1074
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    • 2002
  • The growth and heavy metal experiments revealed oppositive interactions between toxic metals(Zn and Cd) and Mn when the coastal diatom T. pseudonana were used. Cd and Zn inhibited the algal growth rate only at low Mn ion concentrations and this effect could be accounted for an inhibition of cellular Mn take by the toxic metals. Mn and Zn inhibited cellular Cd take and this indicated a reciprocal effects among the metals with respect to metal take. Saturation kinetics modeling of the take data was consistent with two metals competing with each other for binding to the Mn take system and with both Cd and Mn being transported into the cell by that system. Mathematical modeling of Mn and Cd take data revealed evidence fur a Cd efflux system.

A Study on making space planing of take-out coffee shops (테이크아웃(Take-out)커피 전문점의 유형별 공간 구성에 관한 연구)

  • Park Jae-Hee;Byun Lyang-Soun
    • Korean Institute of Interior Design Journal
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    • v.14 no.2 s.49
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    • pp.128-134
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    • 2005
  • This dissertation is about a study on the space planning of take-out coffee shops grouped by type. The classification is based primarily on stand-alone shop, which runs independently, and shop in shop, located inside of another shop with different industry. And its subdivision is characterize by 3 types: Combination type has not only space to enjoy coffee as we can usually see in conventional coffee shops, but also a counter where take-out coffee is served. Separation type has space for drinking coffee and an external booth for easy buy. Booth type is a booth itself or driving (cruising) booth. In conclusion, some take-out coffee shop are exampled and space analysis is made with analytic tools, such as people of preference, location evaluation, functional space division, dimension per person, and planning of traffic line.

Analyzing the Impact of Changes in the Driving Environmenton the Stabilization Time of Take-over in Conditional Automation (조건부 자율주행시 주행환경 변화에 따른 제어권 전환 안정화 시간 영향 분석)

  • Sungho Park;Kyeongjin Lee;Jungeun Yoon;Yejin Kim;Ilsoo Yun
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.22 no.6
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    • pp.246-263
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    • 2023
  • The stabilization time of take-over refers to the time it takes for driving to stabilize after the take-over. Following a take-over request from an automated driving system, the driver must become aware of the road driving environment and perform manual driving, making it crucial to clearly understand the relationship between the driving environment and stabilization time of take-over. However, previous studies specifically focusing on stabilization time after take-over are rare, and research considering the driving environment is also lacking. To address this, our study conducted experiments using a driving simulator to observe take-over transitions. The results were analyzed using a liner mixed model to quantitatively identify the driving environment factors affecting the stabilization time of take-over. Additionally, coefficients for stabilization time based on each influencing factor were derived.

Analysis of Take-over Time and Stabilization of Autonomous Vehicle Using a Driving Simulator (드라이빙 시뮬레이터를 이용한 자율주행자동차 제어권 전환 소요시간 및 안정화 특성 분석)

  • Park, Sungho;Jeong, Harim;Kwon, Cheolwoo;Kim, Jonghwa;Yun, Ilsoo
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.18 no.4
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    • pp.31-43
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    • 2019
  • Take-overs occur in autonomous vehicles at levels 3 and 4 based on SAE. For safe take-over, it is necessary to set the time required for diverse drivers to complete take-over in various road conditions. In this study, take-over time and stabilization characteristics were measured to secure safety of take-over in autonomous vehicle. To this end, a virtual driving simulator was used to set up situations similar to those on real expressways. Fifty drivers with various sexes and ages participated in the experiment where changes in traffic volume and geometry were applied to measure change in takeover time and stabilization characteristics according to various road conditions. Experimental results show that the average take-over time was 2.3 seconds and the standard deviation was 0.1 second. As a result of analysis of stabilization characteristics, there was no difference in take-over stabilization time due to the difference of traffic volume, and there was a significant difference by curvature changes.

A Study on the Choice Attributes and Customer Satisfaction of a Take-out Coffee Shop (테이크아웃 커피전문점의 선택속성과 고객만족에 관한 연구)

  • 김영옥
    • Culinary science and hospitality research
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    • v.9 no.3
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    • pp.141-154
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    • 2003
  • The purpose of this study is to find customer satisfaction at take-out coffee shops by examining their choice attributes, and to find the operational suggestion of the shops by identifying relations between customer satisfaction and choice factors and by finding significant factors, in order to offer subsequential developments for take-out coffee shops. When it comes to choosing a take-out coffee shop, women are found to consider pleasantness, kindness, and warranty more than men do. By age, those in the thirties are found to think much of typicalness, pleasantness, and trust than people in any age do, while those under the twenties kindness. By job, it is found that office workers think typicalness, pleasantness to be important, while students trust The more customers are satisfied at trust and kindness, the more customers are willing to use the shop again. Thus, to make the better service of take-out coffee shops, it requires drastic, continuous training for employees, introduction of specific marketings, management of corporate brand images, manpower administration that will maximize profits with small members, continuous menu development, study of taste, stage preparation and standardized service quality techniques and know-how specific to a coffee shop that will lead customers to revisit the shop.

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