• Title/Summary/Keyword: working platforms

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Cooperative control system of the floating cranes for the dual lifting

  • Nam, Mihee;Kim, Jinbeom;Lee, Jaechang;Kim, Daekyung;Lee, Donghyuk;Lee, Jangmyung
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.10 no.1
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    • pp.95-102
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    • 2018
  • This paper proposes a dual lifting and its cooperative control system with two different kinds of floating cranes. The Mega-erection and Giga-erection in the ship building are used to handle heavier and wider blocks and modules as ships and off-shore platforms are enlarged. However, there is no equipment to handle such Tera-blocks. In order to overcome the limit on performance of existing floating cranes, the dual lifting is proposed in this research. In the dual lifting, two floating cranes are well-coordinated to add up the lift capabilities of both cranes without any loss such that virtually a single crane is lifting, maneuvering and unloading. Two main constraints for the dual lifting are as follows: First, two barges of floating cranes should be constrained as a rigid body not to cause a relative motion between two barges and main hooks of the two cranes should be controlled as main hooks of a single crane. In order words, it is necessary to develop the cooperative control of two floating cranes in order to sustain a center of gravity of the module and minimize the tilting angle during the lifting and unloading by the two floating cranes. Two floating cranes are handled as a master-slave system. The master crane is able to gather information about all working conditions and make a decision to control the individual hook speed, which communicates the slave crane by TCP/IP. The developed control system has been embedded in the real floating crane systems and the dual lifting has been demonstrated five times at SHI shipyard in 2015. The moving angles of the lifting module are analyzed and verified to be suitable for hoisting control. It is verified that the dual lifting can be applied for many heavier and wider blocks and modules to shorten the construction time of ships and off-shore platforms.

A Fatigue Failure Analysis of Fractured Fixing Bolts of a Mobile Elevating Work Platform using Finite Element Methods (유한요소기법을 이용한 고소작업대의 파손된 고정볼트의 피로 파손 분석)

  • Choi, Dong Hoon;Kim, Jae Hoon
    • Journal of the Korean Society of Safety
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    • v.35 no.5
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    • pp.1-8
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    • 2020
  • Mobile elevating work platforms (MEWPs) consist of a work platform, extending structure, and chassis, and are used to move persons to working positions. MEWPs are useful but are composed of pieces of equipment, and accidents do occur owing to equipment defects. Among these defects, accidents caused by the fracture of bolts fixed to the extension structure and swing system are increasing. This paper presents a failure analysis of the fixing bolts of MEWP. Standard procedure for failure analysis was employed in this investigation. Visual inspection, chemical analysis, tensile strength measurement, microstructural characterization, fractography analysis by Optical Microscope(OM) and Scanning Electron Microscopy(SEM), and finite element analysis (FEA) were used to analyze the failure of the fixing bolts. Using this failure analysis approach, we found the root cause of failure and proposed a means for solving this type of failure in the future. First, the chemical composition of the fixing bolt is obtained by a spectroscopy chemical analysis method, which determined that the chemical composition matched the required standard. The tensile test showed that the tensile and yield strengths were within the required capacity. The stress analysis was carried out at five different boom angles, and it was determined that the fixing bolt of MEWP can withstand the loads at all the boom angles. The outcomes of the fatigue analysis revealed that the fixing bolt fails before reaching the design requirements. The results of the fatigue analysis showed primarily that the failure of the fixing bolt was due to fatigue. A visual inspection of the fractured section of the fixing bolt also confirmed the fatigue failure. We propose a method to prevent failure of the fixing bolt of the MEWP from four different standpoints: the manufacturer, safety certification authority, safety inspection agency, and owner.

A Study on Experts' Perception Survey on Elementary AI Education Platform (초등 AI 교육 플랫폼에 대한 전문가 인식조사 연구)

  • Lee, Jaeho;Lee, Seunghoon
    • Journal of The Korean Association of Information Education
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    • v.24 no.5
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    • pp.483-494
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    • 2020
  • With the advent of the 4th Industrial Revolution, interest in AI education is increasing. In order to cultivate talented people with AI competencies who will lead the future, AI education must be conducted in a sound manner at the school site. Although AI education is being conducted at home and abroad, it was determined that the role of the AI education platform is important to implement better AI education, so this study investigated the perception of experts on the AI education platform. A perception survey was conducted based on five criteria: teaching and learning management, educational contents, accessibility, performance of AI education platform, and level suitability of elementary school students. As a results, the number of 103 educational experts selected 'Entry' as the most proper platform among the eight platforms - 'Machine learning for Kids', 'Teachable Machine', 'AI Oceans(code.org)', 'Entry', 'Genie Block', 'Elice', 'mBlock' and etc. Analysis shows that this is because 'Entry' provides quality educational content, has convenient accessibility, is easy to manage teaching and learning, as well as an AI education platform suitable for the level of elementary school. In order to apply various AI education platforms to the school field, it is necessary to train teachers in AI-related training to train them as AI education experts, and to continuously provide opportunities to experience AI education platforms. In this study, there are limitations to what is called 'a population perception survey'. because only 103 people were surveyed, and most of the experts are working in a specific area(Gyeonggi-do). In the future, it is judged that research targeting experts at the national level should be conducted to supplement these limitations.

The Future of Workplace in Vertical Cities: Hanging Gardens, Roof Terraces and Vertical Plazas

  • Reinke, Stephan C.
    • International Journal of High-Rise Buildings
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    • v.9 no.1
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    • pp.71-79
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    • 2020
  • As the workplace evolves in our vertical cities, the need for "think spaces" and the public realm to meet, create and innovate will become integral to tall buildings. These people places are designed to address the social challenges and enhance the co-working environments which are emerging in the dense urban context of our future cities. The design of sky terraces and the "spaces between" offer a greener, more humane and smarter work environment for the future. The public realm should no longer be held down, fixed to the ground plane, but rather become part and parcel of the upper levels of our workplace centers. These collective spaces in our workplace centers must provide a three dimensional matrix of connected and identifiable platforms to leverage the open and progressive future way of working. This will enable social networking and idea sharing, and create multi-dimensional, multi-level business incubators for innovation and creativity. The BCO ( British Council of Offices) has performed a landmark Wellness Matters Report which provides an exemplary roadmap for the future of the workplace. Our future vertical cities must also provide for serendipity in the workplace; a key attribute to drive the information exchange and collaboration that are proven to provide positive and progressive business outcomes. In addition to demonstrating examples of existing built work and the concept of the integrated vertical public realm, the presentation also will consider and define wellness in the workplace as a critical factor in our design strategies and our future workplace environments Hanging Gardens, Roof Terraces and the Vertical Plazas; designed for interchange, wellness, animation and collaboration.

A Conceptual Architecture and its Experimental Validation of CCTV-Video Object Activitization for Tangible Assets of Experts' Visual Knowledge in Smart Factories (고숙련자 공장작업지식 자산화를 위한 CCTV-동영상 객체능동화의 개념적 아키텍처와 실험적 검증)

  • Eun-Bi Cho;Dinh-Lam Pham;Kyung-Hee Sun;Kwanghoon Pio Kim
    • Journal of Internet Computing and Services
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    • v.25 no.2
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    • pp.101-111
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    • 2024
  • In this paper, we propose a concpetual architecture and its implementation approach for contextualizing unstructured CCTV-video frame data into structured XML-video textual data by using the deep-learning neural network models and frameworks. Conclusively, through the conceptual architecture and the implementation approach proposed in this paper, we can eventually realize and implement the so-called sharable working and experiencing knowledge management platforms to be adopted to smart factories in various industries.

Current State and Improvement of Safety Regulations of Working Platform and Working Passage in Construction Sites (건설현장 작업발판 및 가설통로의 안전기준 현황 및 개선점)

  • Jang, Jun Young;Ahn, Hongseob;Oh, Inhwan;Kim, Tae Wan
    • Journal of the Korea Institute of Construction Safety
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    • v.2 no.1
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    • pp.28-35
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    • 2019
  • The average number of deaths in the construction industry reaches 500 per year, and in particular, it is confirmed that the type of accidents and deaths caused by disasters such as work platforms has occupied more than 60% of the total. In this study, we presented a structured and combined solution for technology, management, education, and cost that can solve systematically, politically, and external environmental factors as well as direct influence factors. In addition, we examined the safety and safety standards of domestic and international safety, and discussed implications. First, direct impact factors, organizational impact factors, policy influence factors, and external environmental impact factors were examined and classified into technical, education, and institutional dimensions. Second, in relation to the installation of the work scaffold, the standards (OSHA 1926.452), UK (The Work at Height Regulations 2005 No.735, BS5975), Japan (Labor Safety and Sanitation Regulations) and Germany (DIN 4420_4, DIN EN12810). In the case of domestic safety standards, similar to the foreign safety standards, safety measures such as materials and specifications are applied. However, details related to the installation, assembly and structure of the work platform are somewhat different from those in the United States and the United Kingdom excluding Japan. Using the results of this study, it is possible to understand the cause of the accident of foot pedestrian accident more systematically and comprehensively, and safety managers and researchers are expected to help in the accident investigation.

A Study on the Development of Underwater Robot Control System for Autonomous Grasping (자율 파지를 위한 수중 로봇 제어 시스템 구축에 관한 연구)

  • Lee, Yoongeon;Lee, Yeongjun;Chae, Junbo;Choi, Hyun-Taek;Yeu, Taekyeong
    • The Journal of Korea Robotics Society
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    • v.15 no.1
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    • pp.39-47
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    • 2020
  • This paper presents a control and operation system for a remotely operated vehicle (ROV). The ROV used in the study was equipped with a manipulator and is being developed for underwater exploration and autonomous underwater working. Precision position and attitude control ability is essential for underwater operation using a manipulator. For propulsion, the ROV is equipped with eight thrusters, the number of those are more than six degrees-of-freedom. Four of them are in charge of surge, sway, and yaw motion, and the other four are responsible for heave, roll, and pitch motion. Therefore, it is more efficient to integrate the management of the thrusters rather than control them individually. In this paper, a thrust allocation method for thruster management is presented, and the design of a feedback controller using sensor data is described. The software for the ROV operation consists of a robot operating system that can efficiently process data between multiple hardware platforms. Through experimental analysis, the validity of the control system performance was verified.

Development of S/W Framework for the Industrial Dual-arm Robot (산업용 양팔로봇 제어 S/W 프레임 개발)

  • Choi, Taeyong;Do, Hyun Min;Park, Dong Il;Park, Chanhun;Kim, Doohyung;Park, Kyung-Taik
    • Journal of the Korean Society for Precision Engineering
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    • v.30 no.9
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    • pp.887-891
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    • 2013
  • Human rights at poor working condition is the severe problem in modern manufacturing system. The industrial dual-arm robot is being developed to meet these social issues fundamentally. The dual-arm robot can work instead of human workers. We developed the new dual-arm robot for manufacturing mobile phone and TV. It has advantages such as the solo controller for both arms, the human sized body and arms. The software platform for the industrial dual-arm robot is being developed which has strength in its convenience and intelligence compared to conventional the robot software platforms. Here the development of the dual-arm robot software platform is introduced.

Detection of Sequence-Specific Gene by Multi-Channel Electrochemical DNA Chips

  • Zhang, Xuzhi;Ji, Xinming;Cui, Zhengguo;Yang, Bing;Huang, Jie
    • Bulletin of the Korean Chemical Society
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    • v.33 no.1
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    • pp.69-75
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    • 2012
  • Five-channel electrochemical chips were fabricated based on the Micro-electromechanical System (MEMS) technology and were used as platforms to develop DNA arrays. Different kinds of thiolated DNA strands, whose sequences were related to white spot syndrome virus (WSSV) gene, were separately immobilized onto different working electrodes to fabricate a combinatorial biosensor system. As a result, different kinds of target DNA could be analyzed on one chip via a simultaneous recognition process using potassium ferricyanide as an indicator. To perform quantitative target DNA detection, a limit of 70 nM (S/N=3) was found in the presence of 600 nM coexisting noncomplementary ssDNA. The real samples of loop-mediated isothermal amplification (LAMP) products were detected by the proposed method with satisfactory result, suggesting that the multichannel chips had the potential for a high effective microdevice to recognize specific gene sequence for pointof-care applications.

Smart PZT-interface for wireless impedance-based prestress-loss monitoring in tendon-anchorage connection

  • Nguyen, Khac-Duy;Kim, Jeong-Tae
    • Smart Structures and Systems
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    • v.9 no.6
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    • pp.489-504
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    • 2012
  • For the safety of prestressed structures such as cable-stayed bridges and prestressed concrete bridges, it is very important to ensure the prestress force of cable or tendon. The loss of prestress force could significantly reduce load carrying capacity of the structure and even result in structural collapse. The objective of this study is to present a smart PZT-interface for wireless impedance-based prestress-loss monitoring in tendon-anchorage connection. Firstly, a smart PZT-interface is newly designed for sensitively monitoring of electro-mechanical impedance changes in tendon-anchorage subsystem. To analyze the effect of prestress force, an analytical model of tendon-anchorage is described regarding to the relationship between prestress force and structural parameters of the anchorage contact region. Based on the analytical model, an impedance-based method for monitoring of prestress-loss is conducted using the impedance-sensitive PZT-interface. Secondly, wireless impedance sensor node working on Imote2 platforms, which is interacted with the smart PZT-interface, is outlined. Finally, experiment on a lab-scale tendon-anchorage of a prestressed concrete girder is conducted to evaluate the performance of the smart PZT-interface along with the wireless impedance sensor node on prestress-loss detection. Frequency shift and cross correlation deviation of impedance signature are utilized to estimate impedance variation due to prestress-loss.