• 한국유체기계학회 논문집
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• 제16권2호
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• pp.5-9
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• 2013

The aim of present study is to evaluate the stability of GM(Metacentric Height) calculation and investigate the damping effect of free rolling test. Moreover, GZ(Righting arm in stability) curve shows that it can provide reasonable design conditions for Fish boat. The roll damping characteristics of the improved model for an 7.9 ton class fishing boat are investigated through the free roll test in towing tank. The safety and boarding sensitivity are evaluated by GM calculation and roll motion period. Therefore, the results in this paper describe that the effect for improved hull is more improved than the original hull.

• 한국해양공학회지
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• 제24권1호
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• pp.83-89
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• 2010

This study presents a stability analysis procedure for caisson structures and a case study for a honeycomb slit-caisson. CADMAS-SURF was used to calculate the wave pressures based on an irregular wave with a 50-year period and the data for three regular waves obtained from a target site. Then, the irregular and regular wave pressures were used to obtain the dynamic responses (stresses) of the caisson structure using an explicit time integration program, ANSYS/LS-DYNA. Finally, the DNV code was used for structural and fatigue stability analyses.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 A
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• pp.104-106
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• 2000

Transient Stability of a power systems is its ability to maintain synchronous operation of machine when subjected to a large disturbance. This paper presents a new methodology for speed-up transient stability evaluation in SIME. SIME is a hybrid direct method including time simulation to enhance flexibility. The First features of the proposed method are that generator grouping can be performed even in very stable cases and that the stability of a contingency can be evaluated from a short period of time simulation results. The second features of the proposed method are that using power-angle trajectory and subdividing contingency classification have improved the screening capability.

• Journal of applied mathematics & informatics
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• 제5권3호
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• pp.597-606
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• 1998

In the present study we consider a mathematical model of a non-interactive type autotroph-herbivore system in which the amount of autotroph biomass consumed by the herbivore is assumed to follow a Holling type II functional response. We have also incorpo-rated discrete time delays in the numerical response term to represent a delay due to gestation and in the recycling term which represent a delay due to gestation and in the recycling term which represents the time required for bacterial decomposition. We have derived con-dition for global asymptotic stability of the model in the absence of delays. Conditions for delay-induced asymptotic stability of the steady state are also derived. The length of the delay preserving stability has been estimated and interpreted ecologically.

• 미생물학회지
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• 제13권2호
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• pp.59-63
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• 1975

When the enzyme preparations were at various temperatures for 1 hour, the thermal stability for the enzyme was maximum at $30{\circ}C.$ The optimum temperature for the enzyme activity was at $40{\circ}C.$ When the enzyme preparations were exposed to various pHs for 22 hours, the enzyme stability was maximum at pH 3.8, and it was decreased gradually as the pH rose up to 4.8, above which the stability was greatly restored. When the exposure period was extended from 22 to pH's 3.0 and 5.9, but the stability tended to rise at pH's below 3.0 and above 5.9. The optimum pH for the enzyme activity was obtained at 4.8.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 D
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• pp.2231-2233
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• 2002

Recently NCS(Networked Control System) is widely used in distributed control system design. The insertion of the network in the feedback control loop makes the analysis and design of NCS complex. Especially, the network-induced delay can vary the system stability and even destabilizes the entire control system. This paper deals with the stability analysis method of NCS. Also, we analyze the influence of sampling period and network-induced delay on power plant stability.

• 대한전기학회논문지:시스템및제어부문D
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• 제52권5호
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• pp.268-276
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• 2003

In this paper, we present a new control and monitoring technique for a power system using CAN(Controller Area Network). Feedback control systems having co'ntrol loops closed through a network(i.e. Ethernet, ControlNet, CAN) are called NCSs(Networked Control Systems). The major problem of NCSs is the variation of stability property according to time delay including network-induced delay and computation delay in nodes. We present a new stability analysis method of NCSs with time delay exploiting a state-space model of LTI(Linear Time Invariant) interconnected systems. The proposed method can determine a proper sampling period of NCSs that preserves stability performance even in NCSs with a dynamic controller. We design CAN nodes which can transmit control and monitoring data through CAN bus and apply these to NCSs for a power system. The results of the experiment validate effectiveness of our control and monitoring technique for a power system.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2001년도 춘계학술대회 논문집
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• pp.70-75
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• 2001

Intensive experimental investigations were carried out to provide information of the effects of inflow on the rolling characteristics and stability of ships, which becomes great concern in relation to ship's capsizing. A series of systematic experiments have been performed considering the effects cf combined motion of roll-heave-sway and relevant parameters, such as roll angle and period, tank water height etc. To accommodate this type of experiments with 3-degree of freedom of motion, a bench tester has been developed and verified using existing data. Also, theoretical application of anti-roll tank has been incorporated to support the process of investigation. A model of Ro-Ro ships is used in the present study as this type of vessels, as well as fishing vessels, with large open decks, can loose stability rapidly when there is inflow on the decks.

• 한국전문물리치료학회지
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• 제24권1호
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• pp.1-8
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• 2017

Background: The multiple hop test is an active performance test that has been commonly used to assess individuals with functional ankle instability. Previous studies have suggested that insufficiency of dynamic postural stability and passive stability during dynamic activities can have an influence on performance in the multiple hop test. However, no study has investigated the effects of dynamic postural stability training and ankle bracing on multiple hop test performance in individuals with functional ankle instability. Objects: The purpose of this study was to compare the immediate effects of dynamic postural stability training versus ankle bracing in the performance of the multiple hop test for participants with functional ankle instability. Methods: Twenty-nine participants with functional ankle instability who scored below 24 in the Cumberland Ankle Instability Tool were selected. The participants were randomly divided into two groups: a dynamic postural stability training group (n1=14) and an ankle bracing control group ($n_2=15$). The multiple hop tests were performed before and after applying each intervention. Dynamic postural stability training was performed using visual-feedback-based balance-training equipment; participants in this group were asked to perform a heel raise in a standing position while watching the centering of their forefoot pressure to prevent excessive ankle inversion. Ankle bracing was applied in the control group. Results: When comparing the pre- and post-intervention period for both groups, both methods significantly improved the results of the multiple hop test (p<.05). However, no significant differences were shown between the dynamic postural stability training and ankle bracing groups (p>.05). Conclusion: Both dynamic postural stability training and ankle bracing showed significant improvement (2.85 seconds and 2.05 seconds, respectively) in test performance. Further study is needed to determine the long-term effects of dynamic postural stability training and to determine whether insufficient dynamic postural stability is a causative factor for functional ankle instability.

• Journal of applied mathematics & informatics
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• 제17권1_2_3호
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• pp.269-282
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• 2005

We study the global asymptotic stability, global attractivity, boundedness character, and periodic nature of all positive solutions and all negative solutions of the difference equation $$x_{n+1}\;=\;{\alpha}-{\frac{x_{n-1}}{x_{n}},\;n=0,1,\;{\cdots}$$, where ${\alpha}\;\in\; R$ is a real number, and the initial conditions $x_{-1},\;x_0$ are arbitrary real numbers.