• Title/Summary/Keyword: stability control measures

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A Plan on the Flood Control Ability Improvement Project to maintain stability of existing dams (기존댐 치수능력 증대사업의 시행 방안)

  • Lee, Wan-Ho;Ahn, Hee-Bok
    • Proceedings of the Korean Geotechical Society Conference
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    • 2006.10a
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    • pp.191-201
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    • 2006
  • The flood control ability improvement project on existing dams is the project for prevention of disasters from excessive flood due to climate changes and thus protects lives and property damages by increasing safety of dams. The collapse of dam brings unimaginable disasters, so the project needs to be swiftly conducted by Government's funding. This paper introduces tile examples of the flood control ability improvement projects of multi-purpose and water supply dams, which is conducted in the way of structural measures among 26 dams operated by Kwater.

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Development of float off Operation Design for Mdlti Semi-submersible Barges with Symmetrical Stability Casings (반 잠수식 복수부선의 진수설계)

  • 양영태;최문길;이춘보;박병남;성석부
    • Journal of Ocean Engineering and Technology
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    • v.17 no.2
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    • pp.72-76
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    • 2003
  • This paper presents the design concept and operation results of float-off for FSO (340,000 DWT Class, ELF AMENAM KPONO Project) built on the ground, without dry dock facilities. It was the first attempt to build FSO, completely, on the ground and launch it using DBU (Double Barge Unit, which was connected by rigid frame structure.) The major characteristics of FSO, which are similar to general VLCC type hull, including topside structure, weigh 51,000 metric ton. In order to have sufficient stability during the deck immersion of DBU, while passing through a minimum water plane area zone, proper trim control was completed with LMC (Load Master Computer). The major features of the monitoring system include calculation for transverse bending moment, shear force, local strength check of each connector, based on component stress, and deformation check during the load-out and float-off. Another major concern during the operation was to avoid damages at the bottom and sides of FSO, due to motion & movement after free-floating; therefore, adequate clearances between DBU and FSO were to be provided, and guide posts were installed to prevent side damage of the DBU casings. This paper also presents various measures that indecate the connector bending moment, damage stability analysis, and mooring of DBU during float off.

The Thermal Stability Analysis of Fumes and Mists During the Drying Process of a PCB (PCB 건조공정의 흄과 미스트에 대한 열안정성 분석)

  • Chu, Chang Yeop;Lee, Jung Suk;Baek, Jong Bae
    • Journal of the Korean Society of Safety
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    • v.34 no.4
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    • pp.32-40
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    • 2019
  • During the manufacturing process of a printed circuit board(PCB), fumes and mists are generated as the ink dries on the PCB surface. The generated fumes and mists are deposited in the dryer wall and the exhaust duct. Deposited fumes and mists may present a fire hazard if the dryer temperature control system fails. In this study, the thermal stability of the fumes and mists deposited in the dryer and ducts has been analyzed by experimental methods such as thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), auto ignition temperature (AIT), and multiple mode calorimetry(MMC). According to the experimental analyses, experimental samples are likely to generate gas at the temperature ($180{\sim}240^{\circ}C$) that deviates from the normal operating temperature ($150{\sim}156^{\circ}C$). It has been shown that the thermal stability is degraded when the temperature is deviated from the normal operating temperature. In the end, engineering and management safety measures of accidental prevention have been suggested.

Development of Digital controller for emergency power generating system Using Micro-Controller (마이크로컨트롤러를 이용한 비상발전계통의 제어장치 개발)

  • Jeong, Eull-Gi;Jeon, Hee-Jong;Shon, Jin-Geun;Na, Chae-Dong;Lee, Seong-Bum
    • Proceedings of the KIEE Conference
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    • 2001.07e
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    • pp.100-102
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    • 2001
  • This paper resents digital controller of emergency power generator system. The controller offers an integrated alternative for Genset control, metering and remote monitoring. Proposed controller used 80c196kc one chip microprocessor for digital control, it measures parameters of generator and provides output signals to control starting and stopping of generator. Additionally protection and alarm functions are considered to system stability. As almost parts of controller are embedded by digital microprocessor and FPGA techniques, the controller has a more flexible feature and an improvement of precision. The developed system has a big merit economically and is suitable for any kW size generator.

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Development & Application of Generator Control System Models of EUROSTAG for Stability Study of Power Systems (전력계통의 안정도 해석용 발전기제어계의 EUROSTAG 모형 개발 및 적용)

  • 김학만;오태규
    • Journal of Energy Engineering
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    • v.12 no.2
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    • pp.109-117
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    • 2003
  • Because of the difficulty of acquiring new generation sites and right-of-way, additional units have been added to the existing generation sites and the transmission system has been developed into highly meshed configuration. This structural characteristics may cause restriction on the reliable operation of power systems. In other to meet with this problem, the enhancement of system analysis techniques and establishment of appropriate measures have been required in this situation. In addition the deregulation of electric power industry in Korea would require better tools for power system analysis and control. In this paper, exciter system models, speed governor system models and PSS models of EUROSTAG for stability study are developed. Comparison with simulation results of PSS/E is performed for verification of EUROSTAG models.

Effects of relaxation approach with self-exercise on head posture, static postural stability, and headache in persons with tension-type headache

  • Park, Sang-Yong;Hwang, Sujin
    • Physical Therapy Rehabilitation Science
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    • v.5 no.4
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    • pp.178-184
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    • 2016
  • Objective: Tension-type headache is caused by hormones, foods, irritants, stress, obesity, fatigue, and neck and head trigger points-prolonged abnormal posture. The purpose of this study was to evaluate the effects of relaxation approach on head posture, static postural stability, and headache in persons with tension-type headache. Design: Randomized controlled trial. Methods: Thirty-five persons with tension-type headache participated in this study. This study was a pretest-posttest with a control group design for a duration of 4 weeks (60 min/3 times/1 wk). The participants were randomly allocated to the relaxation approach group (n=18) and the control group with conventional rehabilitation including thermotherapy and transcutaneous electrical stimulation for the same period (n=17). Outcome measures involved forward head posture (FHP), foot pressure, neck disability index (NDI), and six-item headache impact test (HIT-6). Results: Relaxation approach and control groups improved significantly in the amount of forward head posture, neck disability index, and six-item headache impact test scores after training (p<0.05). The control group was found to be significantly different in the amount of FHP, backward foot pressure, NDI, and HIT-6 after training compared to before training (p<0.05). The relaxation approach group significantly improved in forward head posture, neck disability index, and six-item headache impact test compared with control group after training (p<0.05). Neck disability index and six-item headache impact test significantly improved after training compared with before training in the control group (p<0.05). However, the foot pressure was not significantly different between relaxation approach and control groups. Conclusions: This study suggests that treatment with relaxation approach combined with self-exercise would be effective in reducing the amount of forward head posture, neck disability and headache impacts.

Flatness Control System of the Hot Strip by Using Tension Profile between Stands (스탠드간 장력프로파일을 이용한 열연판 평탄도 제어시스템)

  • 홍완기;이준정
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1999.08a
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    • pp.27-36
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    • 1999
  • To have high flatness quality of hot rolled strip in the hot strip finishing mill train, a new inter-stand tension profile measuring device of segmented looper roll type(coined as Flatness Sensing Inter-stand Looper, FlatSIL) and a new flatness control system have been developed in this study. The device measures the strip tension profile across the strip width and informs the strip wave pattern to new flatness control system where work roll bending mode to relieve the strip wave is determined. The existing automatic shape control system which uses laser type shape-meter installed at the outlet of the last finishing mill stand strip tension between down coiler and last finishig mill since the latent wave concealed by the strip tension between down coiler and last finishing mill stand cannot be measured by the laser distance-meter. Thus the existing shape control system is not able to control the flatness through the full strip length. The new flatness control system, however, works for full strip length during strip rolling as far as the tension profile measuring device and work roll bender are on. With the new flatness control system, work roll bender is automatically controller to minimize the latent wave of the running strip and the flatness quality as well as strip travelling stability has been noticeably improved from strip head through body to tail.

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Design and Performance Evaluation of a Marine Engine Fault Detection System Using a Proximity Sensor for a Marine Engine (선박 엔진용 근접 센서를 이용한 선박 엔진 고장진단시스템 설계 및 성능 분석)

  • Pack, In-Tack;Kim, Seung-Hwan;Kim, Dong-Seong
    • Journal of Institute of Control, Robotics and Systems
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    • v.22 no.8
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    • pp.619-626
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    • 2016
  • This paper proposes the design and performance evaluation of a marine engine fault detection system using a proximity sensor for marine engine. Non-linearity is greatly reduced by using the sensor without increasing the response time by applying the CANopen protocol. The CANopen protocol enables the sensor to send initial values and measurement data. The marine engine fault detection system measures crankshaft deflection and the bottom dead center of the crosshead in real-time, which maintains stability and prevents the serious breakdown of the marine engine by use of an interlocking alarm monitoring system.

Idle Quality Optimization Study (공회전시 차량의 소음진동현상의 질적개선에 대한 고찰)

  • ;Norbert Wiehagen
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.05a
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    • pp.342-352
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    • 2003
  • Idle NVH characteristics are one of the most important aspects among the vehicle performances. Vehicle developers are devoted to improve vehicle interior noise and steering wheel and seat vibrations. In order to improve the idle quality, noise and vibration transfer path should be carefully evaluated. Also, effects of various components related to the idle performance should be confirmed. A general procedure for improving the idle qualify is described in detail. The relationship among cylinder pressure characteristics, crankshaft rotational speed variation, and vehicle vibrations is also investigated. Influences of drive shaft, torque converter, air conditioning system, vehicle structure including engine mount system, and idle control parameters on the vehicle idle quality are studied. Weak points of typical vehicles on the idle qualify are identified. Some of improvement measures are proposed and verified.

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The Effects of 12-Week of Proprioceptive Exercise Programs on Chronic Low Back Pain and Sensorimotor Control in Middle-Aged Females in Rural Areasa (12주간의 고유감각자극운동이 농촌지역 중년여성의 만성요통과 감각운동 조절능력에 미치는 효과)

  • Eun-Joo Kim
    • Journal of Advanced Technology Convergence
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    • v.3 no.1
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    • pp.33-42
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    • 2024
  • This study applied a props-based exercise program for 12 weeks to women in their mid-50s in rural areas who complained of back pain, and applied VAS (visual analogue scale), static balance ability left and right, front and back, and sensory movement. Ability Physical stability The left and right, before and after physical changes were investigated. The study subjects were randomly assigned to an experimental group (EG) of 24 people and a control group (CG) of 20 people. For the homogeneity test between the experimental group and the control group, an independent t-test was conducted to analyze the significant difference in average. When homogeneity was secured, two-way ANOVA repeated measures ANOVA was performed. As a result, there was an interaction effect between the group and the 12 weeks period. However, the VAS between periods within the group, static balance ability left and right, before and after, and sensorimotor ability and body stability left and right, before and after showed improved results with significant average differences. After 12 weeks between groups, the experimental group showed significant improvement effects in all variables.