• Journal of The Korean Society of Integrative Medicine
• /
• v.12 no.1
• /
• pp.139-150
• /
• 2024

Purpose : Scapular dyskinesis, it have been shown to be common in overhead athletes and has been associated with RC muscle strength. Posterior shoulder tightness (PST) has been suggested as an important factor causing scapular dyskinesis. Therefore, rehabilitation programs should focus on a posterior shoulder stretch combined with scapular stabilization exercise (PSSE) intervention. Determine the effects of posterior shoulder stretch combined with scapular stabilization exercise on the rotator cuff (RC) muscles strength, functional strength ratio (FSR), range of motion (ROM), and pain. Methods : 30 adolescent baseball players participated and subjects were allocated PSSE group (n=15) or the SSE group (n=15). Both group performed a 6-weeks intervention and measured of isokinetic peak torque/body weight (PT/BW) of concentric external rotator (CER), eccentric external rotator (EER), concentric internal rotator (CIR), eccentric internal rotator (EIR), FSR, ROM, and pain. Results : After 6 weeks PSSE, significant increase CER PT/BW (+6.02±4.76 %), EER PT/BW (+5.39±4.22 %), EER to CIR ratio (+.17±.16), and internal rotation ROM (+15.08±3.57 °). Whereas, significant decrease EIR to CER ratio (-.14±.18), external rotation ROM (-12.00±6.94 °), and GIRD (-17.41±2.84 °) compared with pre-intervention. No significant difference of isokinetic PT/BW of CIR and EER post-intervention. In the SSE group showed no significant difference all measurements for isokinetic PT/BW, FSR, and ROM post-intervention. The pain was significant improve both PSSE group (-3.25±1.60) and SSE group (-2.83±1.85) post-intervention. Conclusion : Both the PSSE and SSE interventions led to more pain relief. However, only the PSSE group showed ROM, CER, EER PT/BW, and FSR improvements. These results might suggest that the PSSE intervention is a more effective program for improving RC muscle strength and balance, in particular, concentric and eccentric ER muscle strength, FSR and can expect to prevent shoulder injuries in adolescent baseball players with scapular dyskinesis.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.7
• /
• pp.4494-4499
• /
• 2014

The margin of transient stability of a weak grid system is very low because of the small short-circuit ratio and large impedance. If the fault of the weak grid is cleared by the protection system, one of the major lines is disconnected after the fault is cleared. This further reduces the system strength. Therefore, it is necessary that a new generation system be added to the weak grid to enhance the transient stability margin. A conventional synchronous generator and wind turbine generator were added to a base grid system. The results of transient stability analysis with additional generators using PSSE were compared. The simulations showed that wind turbine generators provide good damping performance and enhance the transient stability margin based on CCT up to 5 times.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.27 no.1
• /
• pp.68-75
• /
• 2013

This paper presents a scheme to improve transient stability using Newton's Approach for generation rescheduling. For a given contingency, the energy margin and sensitivities are computed. The bigger energy margin sensitivity of generator is, the more the generation of the generator effects to the transient stability. According to energy margin sensitivity, the control variables of generation rescheduling are selected. The fuel cost function is used as objective function to reallocate power generation. The results are compared to the results of time simulation to show its the effectiveness.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.59 no.3
• /
• pp.506-514
• /
• 2010

Defense systems are needed to prevent catastrophic failures of a power grid due to cascaded events. Cascaded events can be occurred by power flow overload. Especially, it is the most dangerous problem that overload line is outage, because it can make the power system face danger of cascaded. In this paper, vulnerability evaluation for monitoring wide are outage is proposed using by configuration information of transmission systems. This method of vulnerability evaluation is considered direct effect and indirect effect of power flow, especially overload. What is more, it can be used when the configuration of power system changes, as simple fault occurs or maintenance of facility. In the case studies, the estimation and simulation network have been testified and analysed in PSSE and C programming.

• Proceedings of the KIEE Conference
• /
• 2005.07a
• /
• pp.670-672
• /
• 2005

발전원이 다른 계동으로 연계된 춘천, 남춘천변전소의 태전선로간 Loop 시행시 일부배전선로가 Trip되는 현상에 대하여 PSSE 검토 TOOL을 활용하여 계통을 모의하고 변압기 병렬운전조건에 대한 물리적 의미와 검토대상 배전선로 계통특성, 주변 발전원의 발전력과의 상관관계를 기술검토를 통하여 계통특성을 분석함으로써 Loop시행이 가능한 계통여건을 파악, 선로 운영의 최적방안을 제시하고자 한다.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.6
• /
• pp.2966-2970
• /
• 2013

In this paper, a simulation study on dynamic characteristics of wind turbine generators is performed. The generation of electricity using wind turbines is being recently spotlighted as a renewable way. The wind is an infinite primary energy source. Further, other environmental impacts of wind power are limited as well. Therefore, the wind turbine generation itself has many advantages. However, when generators using wind turbines are connected to the conventional power system, the impact of the power system is different from that of the power system that consists of only synchronous generators, especially in dynamic characteristics. Therefore, it is essential to examine the characteristics of wind turbines in order to ensure reliable wind turbine generation in the power system containing wind turbine generators. In this paper, the dynamic characteristics of GE1.5MW wind turbine are simulated by using PSS/E. In the simulation of GE1.5MW wind turbine, wind speed variation, load change and voltage deviation of infinite bus are considered.