• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.15 no.1
• /
• pp.34-41
• /
• 2016

Bar camber is a phenomenon in which a material with a deformation gradient across its width is bent in the right or left direction in the roll gap. This paper proposes a dynamic setup approach for a side guide for reducing bar camber. A bar tracking scheme using a rotary encoder was adopted to fix an operation point for the side guide. The guiding pressure was utilized for measuring the actual width of the bar with camber. Based on the accurate position and width of the bar, the side guide was dynamically set and operated at the actual roughing train in a hot strip rolling mill. The amount of camber was reduced notably when the dynamic setup scheme was installed in the side guide. 78% of the bars tested had a camber in the range of ${\pm}20mm$, which was an improvement of 27% in terms of production yield.

• Journal of the Korean Society of Safety
• /
• v.20 no.2 s.70
• /
• pp.119-126
• /
• 2005

Load bearing structural members in a wide variety of applications accumulate damage over their service life. From a standpoint of both safety and performance, it is desirable to monitor the occurrence, location, and extent of such damage. Structures require complicated element models with a number of degrees of freedom in structural analysis. During experiment much effort and cost is needed for measuring structural parameters. The sparseness and errors of measured data have to be considered during the parameter estimation Of Structures. In this paper we introduces damage identification algorithm by a system identification(S.I) using static and dynamic response. To study the behaviour of the estimators in noisy environment Using Monte Carlo simulation and a data measured perturbation scheme is adopted to investigate the influence of measurement errors on identification results. The assessment result by static and dynamic response were compared, and the efficiency and applicabilities of the proposed algorithm are demonstrated through simulated static and dynamic responses of a truss bridge. The assessment results by each method were compared and we could observe that the 5.1 method is superior to the other conventional methods.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.14 no.3
• /
• pp.473-485
• /
• 1994

Vibration control of concrete slab mounting precision instrument is needed to make the working vibration environments in frequency domain as well as time domain. In order to take the vibration control countermeasures, signal and system analyses of the concrete slab are processed. Through them the dynamic responses of concrete slab are obtained in frequency domain, and frequency response functions are acquired by exciting the concrete slab and measuring dynamic responses at various points across its surface. The dynamic characteristics of concrete slab are determined by experimental modal analysis. Based on modal parameters from a set of frequency response function measured, it is possible to investigate the effects of potential design modifications and reduce the dynamic response of concerned point by moving or suppressing an objectionable modal resonance conditions through structural dynamics modification.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.27 no.3
• /
• pp.93-114
• /
• 2002

This paper suggests a dynamic balanced scorecard (DBSC) model employing the concept of system dynamics (SD), which could overcome the limitations inherent in the conventional balanced scorecard (BSC) and facilitate strategic learning process in organizations. The BSC has been a successful framework for measuring an organization＇s performance in various Perspectives through translating an organization＇s vision and strategy into an interrelated set of key performance indicators and specific actions. The BSC, while having significant strengths over traditional performance measurement methods, however, has its own limitations, due to its static nature, such as overlooking two-way causation between performance Indicators and neglecting the impact of delayed feedback flowing from the adoption of new strategies or policy changes. To overcome these limitations, we employs SD, a methodology for understanding complex systems where dynamic feedback among the interrelated system components significantly impact on the system outcomes. The SD simulation model in the form of DBSC we suggest in this paper would serve as a useful strategic learning tool for facilitating an organization＇s communication process through various scenario analyses as well as predicting the dynamic behavior pattern of their key performance measures over a future time frame. For the demonstration purpose, we apply the DBSC model to Korea Coal Corporation (KoCoal ) BSC case.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.24 no.2
• /
• pp.83-93
• /
• 2020

Dynamic pressure transducer needs to be flush-mounted on hardware due to frequency response characteristics of pressure transmission system. However, it is sometimes necessary to be mounted in recessed configuration due to insufficient space for sensor installation and for protection of sensor from thermal damage. Dynamic response characteristics should be considered due to distortion of original dynamic pressure signal in the pressure transmission system. In this study, small perturbation model and 2nd order reduced model were compared with experiments and a guideline for selecting a frequency response model was suggested.

• Journal of Institute of Control, Robotics and Systems
• /
• v.7 no.6
• /
• pp.518-522
• /
• 2001

The main problem of the calibration of robots is to measure the position and orientation of a robot end effector. The calibration methods can be used as tool to improve the accuracy of robots without change of the arm or control architecture or robots. But such calibration methods require accurate measurements. Dynamic measurement of position and orientation provides a solution for this problem and improves dynamic accuracy by dynamic calibration of robots. This paper describes the development of the laser tracking system capable of determining the static and dynamic performance of industrial robots. The structure and systems components are presented and basic experimental results are included to demonstrated the instrument performance. The system can be applied to the remote controlled mobile robots as well s the calibration of robots.

• Journal of the Korean Society of Safety
• /
• v.15 no.4
• /
• pp.1-7
• /
• 2000

In this paper, an investigation was performed on the ModeII dynamic interlaminar fracture toughness of unidirectional CFRP laminates. The stacking sequences used in this experiment are two kinds of [$0_20$] and [$0_{10}F_20_{10}$]. In the experiments, Split Hopkinson's Bar test was applied to dynamic and notched flexure test. The Mode II fracture toughness of each unidirectional CFRP was estimated by the analyzed deflection of the specimen and J-Integral with the measured impulsive load and reactions at the supported points. As an experimental results, the specimen [$0_{10}F_20_{10}$] appears greater than that of [$0_20$] for the J-integral and displacement velocity at a measuring point within the range of experiment.

• Wind and Structures
• /
• v.24 no.4
• /
• pp.333-350
• /
• 2017

Differing from the fixed-type, the dynamic motion of floating-type offshore wind turbines is very sensitive to wind and wave excitations. Thus, the sensing and monitoring of its motion is important to evaluate the dynamic responses to the external excitation. In this context, a monitoring system for sensing and processing the wind-induced dynamic motion of spar-type floating offshore wind turbine is developed in this study. It is developed by integrating a 1/00 scale model of 2.5MW spar-type floating offshore wind turbine, water basin equipped with the wind generator, sensing and data acquisition systems, real-time CompactRIO controller and monitoring program. The scale model with the upper rotatable blades is installed within the basin by means of three mooring lines, and its translational and rotational motions are detected by 3-axis inclinometer and accelerometers and gyroscope. The detected motion signals are processed using a real-time controller CompactRIO to calculate the acceleration and tilting angle of nacelle and the attitude of floating platform. The developed monitoring system is demonstrated and validated by measuring and evaluating the time histories and trajectories of nacelle and platform motions for three different wind velocities and for eight different fairlead positions.

• Journal of the Korean Society for Railway
• /
• v.14 no.2
• /
• pp.137-142
• /
• 2011

A bimodal tram is a new design vehicle introduced to improve a current transportation system, and it has advantages of a bus and a subway. A pipe truss bridge, an exclusive road of the bimodal tram, is constructed for introduction of the bimodal tram. An analysis of dynamic response characteristics is required because this new bridge has never constructed before. A speed increasing test on the pipe truss bridge was conducted with attaching a sensor to bottom of the bridge. Also, Dynamic response characteristics were analyzed by measuring displacements, the maximum vertical and horizontal acceleration about the new bridge through the experiment.

• Journal of Fashion Business
• /
• v.15 no.6
• /
• pp.40-55
• /
• 2011

The purpose of this research is to review testing principle, testing design and experimental results of the four dynamic moisture movement testers. The research analyzes Moisture Manager Tester (MMT), Alambeta Instrument, Dynamic Surface Moisture Movement Tester, and Gravimetric Absorbent Testing Method based on American Society for Testing and Material (ASTM) E 96 which is an international standard testing method. Although many of researches use ASTM E 96 to measure moisture movement on a fabric, it has several weaknesses, such as long experimental time and a physical change of sample by a holder of the frame. Hence, lots of researchers have studied and developed the new measurement systems measuring moisture management on a fabric or garment and ultimately mimic heat energy and perspiration created by the human body. These moisture management systems use a variety of parameters, such as electricity, color, and sensor to measure their movement in the fabric. Through comparison with the existing tester (ASTM E 96), the research recognizes the strength and weakness in the dynamic moisture movement testers.