• Title/Summary/Keyword: Impact control

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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.

Metrics for evaluation of heavy-weight impact noise generated by impact ball (임팩트 볼에 의한 중량충격음의 평가 메트릭스 설정)

  • Lee, Pyoung-Jik;Jeong, Young;Jeon, Jin-Yong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.11a
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    • pp.636-640
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    • 2006
  • In this study, metrics for evaluation of heavy-weight impact noise were investigated. Heavy-weight impact noises generated by impact ball were recorded in real apartments using binaural microphone. Those sounds were classified into three groups according to frequency characteristics in order to control aspects which affect subjective responses to heavy-weight impact noise. Sound sources for auditory experiment were selected based on the classification result. Then auditory experiments were conducted to investigate the relationship between level indices and subjective responses. The results showed that $L_{Aeq},\;L_{Amax}$ and $LL_z$ as well as $L_{iFmax,AW}$ were highly correlated with subjective response. Therefore, $L_{Aeq}$ and $L_{Amax}$ can be used as metrics for evaluation of heavy-weight impact noise. In further studies, it is needed to verify classification of heavy-weight impact noise generated by bang machine and impact ball.

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The Influence of Sales-force System on Salesperson's Job Attitude and Sales Performance (영업통제시스템이 판매사원의 직무태도와 판매성과에 미치는 영향)

  • YI, Ho-Taek;YU, Jung-Rim
    • Journal of Distribution Science
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    • v.17 no.11
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    • pp.81-92
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    • 2019
  • Purpose: The salesperson, the core of the operating activities, plays the role of connecting the inside and outside of the company, representing the company to the consumer and identifying and responding to the customer's needs. The department store industry is the most representative retail industry in South Korea, and competition among its peer group and industry is intensifying, requiring differentiated service sales activities and performance from its employees. This study divided the sales force system into activity control(process-oriented control) and output control(performance-oriented control) and verified the differential impact on the job attitude of the salesperson (e.g., job satisfaction and burn-out), respectively. In addition, the effect of job satisfaction and burn-out of the salesperson on the job performance were checked. Research design, data, and methodology: The survey was conducted on 200 sales people working at five branch stores of Hyundai department store in Seoul, and 194 of them were analyzed. The reliability and validity of the variables were analyzed and hypotheses were verified through the SEM. Results: Results have shown that activity control has a greater impact on burn-out compared to output control, and output control has a greater impact on job satisfaction compared to activity control. It has been shown that the salesperson's burn-out does not affect sales performance, but that job satisfaction has a positive effect on sales performance. Conclusions: This study examines the effect of sales force management system such as activity control and output control, on the job attitude and sales performance in department stores. According to the results of this research, each of two control systems have a discriminatory effect on the job attitude variables. For the sales managers of department store, it is recommended to increase the efficiency of sales management by increasing the use of outcome control compared to activity control.

Experimental Study and Finite Element Analysis about Vehicle Laminated Glass Subject to Headform Impact (머리모형 충돌에 의한 자동차 접합유리의 실험적 연구 및 유한요소해석)

  • Choi, Jihun;Oh, Wontek;Kim, Jonghyuk;Park, Jongchan
    • Transactions of the Korean Society of Automotive Engineers
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    • v.25 no.3
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    • pp.374-379
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    • 2017
  • In vehicle to pedestrian accidents, cracks occur in the vehicle laminated glass due to impact of a pedestrian's head. In this study, FMH(Free Motion Headform) was used to experiment on and analyze the crack patterns on a vehicle laminated glass that collides with an adult headform at speeds of 20 km/h, 30 km/h, and 40 km/h, respectively. Applying the acquired experimental data and material property of the vehicle laminated glass to the structural analysis program LS-Dyna, we could develop the FE model of vehicle laminated glass similar to real vehicle laminated glass. We could estimate the head impact velocity and pedestrian's vehicle impact velocity using the Madymo program.

Liquidity and Solvency Management and its Impact on Financial Performance: Empirical Evidence from Jordan

  • DAHIYAT, Ahmad Abdelrahim;WESHAH, Sulaiman Raji;ALDAHIYAT, Mohammad
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.5
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    • pp.135-141
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    • 2021
  • The study aims to examine the impact of liquidity and solvency management on the financial performance of Jordanian manufacturing companies listed on the Amman Stock Exchange, for a period of 10 years from 2010 to 2019. The size of the company was used as a control variable. The study employs Return on Assets (ROA) and Earnings Per Share (EPS) to measure financial performance. Current ratio (CR) and total debts to total assets were used as proxies for liquidity and solvency management, while logarithm of total assets was used to measure the size. Correlation and multi regression analyses have been applied to analyze the data. The results show a statistically significant impact of independent and control variables (liquidity and solvency management and the size of the company) on financial performance, while the detailed results of the hypotheses indicate that liquidity has an insignificant reverse impact on financial performance. With respect to other variables, there is a significant positive impact of size on performance and a significant negative impact of solvency on performance. The study suggests in light of results, increasing investments in companies' assets by focusing on internal financing, such that large-sized companies with low leverage will have a good performance.

Study on the Power-Grid Impact and Optimal Charging Control Strategy with PHEV Market Penetration (PHEV 시장 형성 시 전력망에 미치는 영향 및 최적 충전 제어 전략에 관한 연구)

  • Roh, Chul-Woo;Kim, Min-Soo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.33 no.4
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    • pp.278-287
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    • 2009
  • Plug-in hybrid electric vehicle (PHEV) with capability of being recharged from the power-grid will reduce oil consumption. Also, the PHEV will affect the utility operations by adding additional electricity demand for charging. In this research, the power-grid impact by demand of PHEV charging is presented and the optimal charging control strategy for utility operators is proposed with simulated data. The penetration of PHEV is assumed to be 50% in the circumstances of Korean passenger car market and Korean power-grid market limitedly. To obtain smooth load shape and utilize the surplus electricity in power-grid at midnight and dawn, the peak of charging demand should be controlled to be located before 4:00 a.m., and the time slot which can supply the electricity power to PHEV should be allowed between 1:00 a.m.$\sim$7:00 a.m.

Trajectory Optimization for Impact Angle Control based on Sequential Convex Programming (순차 컨벡스 프로그래밍을 이용한 충돌각 제어 비행궤적 최적화)

  • Kwon, Hyuck-Hoon;Shin, Hyo-Sub;Kim, Yoon-Hwan;Lee, Dong-Hee
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.68 no.1
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    • pp.159-166
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    • 2019
  • Due to the various engagement situations, it is very difficult to generate the optimal trajectory with several constraints. This paper investigates the sequential convex programming for the impact angle control with the additional constraint of altitude limit. Recently, the SOCP(Second-Order Cone Programming), which is one area of the convex optimization, is widely used to solve variable optimal problems because it is robust to initial values, and resolves problems quickly and reliably. The trajectory optimization problem is reconstructed as convex optimization problem using appropriate linearization and discretization. Finally, simulation results are compared with analytic result and nonlinear optimization result for verification.

Regulatory Development of Environmental Impact Assessment in Korea (한국 환경 영향평가제도의 변천)

  • Chang, Chun-Ki;Lee, Jae-Woon;Kwon, Myeong-Hee;Jeong, Dong-Hwan
    • Journal of Environmental Impact Assessment
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    • v.2 no.2
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    • pp.95-103
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    • 1993
  • EIA has been introduced as a tool for environment protection into promulgation of the Environment Preservation Act in 1977, which replaced the Pollution Control Act in Korea. EIA system has been improved with the enlargement of project type, public participation, guideline improvement, and regulatory development. Recently, Environmental Impact Assessment(EIA) Act will have an important role for sustainable development. This article deals with regulatory development, implementation order, EIA project type, and EIS preparation guidelines by Act promulgated and amended, also it explains comparison analysis of Environmental Policy Act and Environment Impact Assessment Act Major results are summarized in the table.

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A Study on the Systematization of the Legal Framework for Environmental Impact Assessment Systems (환경영향평가법(環境影響評價法)의 체계정립(體系定立)에 관한 연구(硏究))

  • Jeong, Yeon-Man
    • Journal of Environmental Impact Assessment
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    • v.10 no.3
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    • pp.195-209
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    • 2001
  • The objective of this study is intended to propose plans for reforming environmental impact assessment(EIA) systems by reviewing the current legal systems of EIA related laws and their implementation status in Korea, and by comparing the Korean situation to EIA systems in several foreign countries. This study tried to integrate all EIA related systems scattered over several laws into one comprehensive EIA law, and also to develop legal procedures necessary to accomplish the legislative purpose of the integrated EIA law. Therefore, I propose four reforms (1) All EIA systems should be integrated into one comprehensive EIA act. (2) Administrative plans and policies, though environmentally harmful, which are not currently subject to any prior consultation system, should be covered by the prior consultation system. (3) A screening or scoping should be adopted. (4) Widen civil participation should be encouraged and the administrative control enforcement and introduction of group litigation or citizen suits would be considered.

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Finite element analysis and experiment on the formation of adiabatic shear band in 4340 steel (4340강의 단열 전단밴드생성에 대한 유한요소해석 및 실험적 고찰)

  • 정동택;유요한
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.5
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    • pp.1134-1143
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    • 1994
  • A study of adiabatic shear band formation and propagation of 4340 steel was done using the stepped speciment which was subjected to high velocity impact. The high velocity impact was performed on compression Hopkinson bar impact machine. After the controlled impact, the specimen was prepared for visual inspection. Numerical simulation was also performed with same geometrical dimension using explicit time integration finite element code. Experimental results were then compared with the numerical prediction. It was found that the numerical prediction is quite accurate, average thickness of adiabatic shear band is about $10{\mu}m$, the macro crack around shoulder is due to folding, and the deformation control ring is effective to freeze the propagation of adiabatic shear band.