• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.4
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• pp.59-64
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• 2018

Construction schedule acceleration due to unreasonable construction planning frequently leads to construction accidents. In order to avoid such inevitable acceleration and to ensure safety in construction sites, there is a need for objective standards to determine appropriate construction duration for each construction process earlier in the process. In order to achieve the goal, intensive experts interviews were firstly conducted to identify candidate drivers affecting construction schedule of road tunnel excavation works. Then, a total of 34 field data was collected from on-going sites to analyze. It was found that actual excavation length per one day on site is varied mostly by Rock Mass Rating(RMR) types from various statistical analyses. Therefore an one-way table of excavation length per a day by RMR types were presented in a form of percentile. The results will help industry experts determine the most appropriate construction schedule for the works, which eventually lead to a zero accident site in many ways.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.654-658
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• 2003

In this study a control system with variable gain schedule using real speed and moving direction is proposed to control a Permanent Magnet Linear Synchronous Motor (PMLSM) with Z-axis operation structure. The implementation of the controller is designed on the DSP TMS320C32 board. PMLSM is operated by using 4-point absolute positions profile with each velocity, acceleration and deceleration. The direction of the initial angle action for starting is set from the lower limit point to the upper limit point on PMLSM operation stroke. The effectiveness of a control system with variable gain schedule is demonstrated by some experimental results.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.92-97
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• 1988

The path planning is done at the joint level. Cubic spline functions are used for constructing joint trajectories for industrial robots. For N-joint robot, Cartesian knots are transformed into N sets of joint displacements, with one set for each joint. For industrial application the speed of operation affects the productivity. An algorithm is developed to schedule the time intervals between each pair of adjacent knots such that the total traveling time is minimized subject to the physical constraints on joint velocties acceleration and jerks.

• Industrial Engineering and Management Systems
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• v.8 no.4
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• pp.239-246
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• 2009

This paper deals with the makespan minimization problem of job shops. The problem is known as one of hard problems to optimize, and therefore, many heuristic methods have been proposed by many researchers. The aim of this study is also to propose a heuristic scheduling method for the problem. However, the difference between the proposed method and many other heuristics is that the proposed method is based on depth-first branch and bound, and thus it is possible to find an optimal solution at least in principle. To accelerate the search, when a node is judged hopeless in the search tree, the proposed flexible branch and bound method can indicate a higher backtracking node. The unexplored nodes are stored and may be explored later to realize the strict optimization. Two methods are proposed to generate the backtracking point based on the critical path of the current best feasible schedule, and the minimum lower bound for the makespan in the unexplored sub-problems. Schedules are generated based on Giffler and Thompson's active schedule generation algorithm. Acceleration of the search by the flexible branch and bound is confirmed by numerical experiment.

• Korean Journal of Construction Engineering and Management
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• v.6 no.5 s.27
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• pp.139-147
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• 2005

During a typical construction project, a contractor nay often find that the time originally available or normally expected to perform its work has been severely reduced. To finish the project by the completion date, the contractor is forced to find a way to speed up the progress of its work to compensate for the reduction in available time. The most frequent initial reaction of contractors to this situation is to increase on-site manpower by working longer time (overtime), adding more workers (overmanning), or implementing shift work (shift work) to increase the rate of progress. The goals of this study were to investigate how these three methods affect labor productivity and to quantify their impact on labor productivity by analyzing real project data collected from sheet metal contractors and mechanical contractors in the US.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.446-451
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• 2004

Over testing problems of satellites and theirs components have been issued due to their effects on satellite development cost and schedule. Force limited vibration tests were introduced as solution of the problems in 1980s. Over testing phenomena occurs due to the lack of similarity on interface impedance. Force limited vibration tests control interface force to simulate actual interface impedance. In this research, force limited vibration tests are applied on two satellites environmental tests. Force limits are calculated by using TDFS method and Semi-Empirical method. Four force sensors are employed to control interface force. The tests prove that force limited control reduced maximum interface acceleration in order of 3.

• International Journal of High-Rise Buildings
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• v.8 no.3
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• pp.185-192
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• 2019

Citic Tower is the first over-500 m-tall super highrise building in the world, located in the high seismic intensity area with paek ground acceleration over 0.2g in 475 years. This project is unique in its complexity, large volume, and challenging site conditions (zero site for construction). The traditional techniques can hardly meet safty, quality and schedule requirements of the construction. This article introduces the key construction technologies that are innovatively developed and applied in Citic Tower project construction, including intelligent super-high-rise building integrated construction platform system, independently developed by the CCTEB; Jump-Lift Elevator, which is the first of the kind with service height over 500 meters; combined temporary-and-permanent fire protection systems. The BIM technology is also applied in this project. Through technical innovation, and utilization of technologies, construction speed and safety had been greatly improved.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.2
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• pp.142-149
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• 2004

PMLSM(Permanent Magnet linear Synchronous Motor) has widely applied to industrial automations, machine tools and semiconductor equipments due to the merit on the reduction of noise, vibration and the superior dynamic characteristics in comparison to the conventional method, which uses mechanical transfer equipments. Especially, in the case of applying to Z-axis operation structure, control system needs the method of an initial angle setting and the improvement of up/down operation characteristics. This paper proposes an initial angle setting algorithm and a variable gain schedule using real speed and moving direction to improve up/down operation characteristics. The effectiveness of proposed algorithms Is demonstrated by comparing to a conventional gain system via 4-point absolute positions profile with each velocity, acceleration and deceleration.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.8 no.4
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• pp.275-281
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• 2014

The purpose of this study was development and evaluation of putting training system with specialized guides which were adjustable its width and changeable its distance from the ball. The system hardwares that used in this study were made by LEGO NXT and Tetrix set. The system software was made by LabVIEW ver. 2010. The subjects were organized in non-experts(10persons) and KPGA(5persons) players. The putting training schedule was composed of 10 sets and each sets were identically same, which were organized in 4 different width of its guide at 3 different distance from the ball hitting spot, 3 repetition each. The speed/acceleration in wrist area and movement in head area were both reduced by the putting training. Most of testees submitted positive comments in aspect of concentration and motivation. This training method which had changeable width and distance will be able to adapt easily to another sports for the handicapped and the elderly such as ParkGolf or Gateball.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.344-351
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• 2016

In the point of view of a train operator, the main concern with a train operation is not only to maintain a time schedule, but also to decrease the energy consumption as much as possible. Generally for a manual drive, a train conductor controls the train acceleration and deceleration by controlling the notches not to exceed the regulation velocity by considering the given maximum velocity profile for an operation route. For this case, the guideline for a conductor is needed to choose the proper notches by applying the notch optimization so as to drive at the regulation velocity and minimize energy consumption simultaneously. In this paper, the real-time notch optimization plan is suggested using a genetic algorithm that optimizes the notches for the remaining route in real time when the event occurs that track information or regulation velocity profile of the remaining route changes during train operation as well as a normal operation situation. An energy saving effect and the convergence behavior of the optimal solution obtained was analyzed in a genetic algorithm.