• Journal of the Society of Naval Architects of Korea
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• 제43권1호
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• pp.50-58
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• 2006

Free running model tests gives us only maneuvering indices not hydrodynamic derivatives. For this reason, system identification method has been applied to the measured data to identify mathematical model describing hydrodynamic force. However It is difficult to obtain complete set of maneuvering derivatives because of strong correlation of sway velocity and yaw rate. Therefore, in this paper, we assumed that sway velocity related coefficients would be obtained by oblique towing test. and then proposed new procedure to estimate yaw related coefficients. To do this, correlation and regression analyses were carried out to establish modified model and estimate maneuvering derivatives. Also D-optimal rudder input scenario was found based on the modified model and confirmed the validity of its sufficient richness as a input scenario.

• Journal of the Korean Society of Marine Environment & Safety
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• 제18권6호
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• pp.591-596
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• 2012

Recently, a vessel's maneuvering performance is considered to be an important subject to secure safety at short sea shipping. Especially the high turning performance, which is required to avoid the marine pollution by the ships that was grounded, becomes more severe. In this paper, we discuss the effect of increasing rudder force on turning performance of short sea shipping ship by free running test in towing tank. First of all, we make the 47K PC model ship and high-lift rudder using Coanda effect. And we make the free running test system for the turning test in towing tank. And also we perform the turing test of 47K PC model in several changes of Coanda jet momentum and evaluate the turing performance such as advance and tactical diameter. Finally, we confirm that the increasing of rudder force is very effective to improvement of turning performance of short sea shipping ship.

• Transactions of the Korean Society of Automotive Engineers
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• 제19권4호
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• pp.121-129
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• 2011

Hydrocarbons which are the main sources of VOCs from motor vehicles are emitted not only from the engine exhaust gas but also from evaporation of the fuel in storage and supplying systems. Evaporative emissions from gasoline fuel systems could be classified by diurnal, hotsoak and running loss. Diurnal loss test procedures are different as countries. Korea introduced new evaporative regulation in 2009 with 24hour VT-shed test procedure and relaxed emission standards. The estimations on different test procedures in this study show that the new Korean regulation get a little more severe than before and the 2 day diurnal loss test of U.S. is the most severe. So the test procedures as well as the stronger standards should be considered in the next evaporative emission regulation to reduce VOCs from motor vehicles. The important parameters to affect evaporative emissions are air and fuel temperature and fuel vapor pressure. Diurnal loss increases exponentially as rising air temperature and vapor pressure. The effects of vapor pressure on running loss are different as the capacities of canisters. Tests with simulating real temperature and driving conditions show that hydrocarbons in evaporative emissions could be more than those in exhaust gas in summer season because of the higher air temperature.

• Korean Journal of Applied Biomechanics
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• 제28권1호
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• pp.29-35
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• 2018

Objective: The purpose of this study was to determine the asymmetry of vertical ground reaction force (GRF) components between dominant and non-dominant legs in rested and fatigued states in prolonged running. Method: Twenty healthy men, heel strikers, were included (age: $24.00{\pm}5.0years$; height: $176.1{\pm}6.0cm$; body mass: $69.0{\pm}6.0kg$) in this study. Subjects ran on an instrumented treadmill for 130 minutes. During treadmill running, GRF data (1,000 Hz) were collected for 20 strides at five minutes (rested) and 125 minutes (fatigued) running while they were unaware of collecting data. Asymmetry indexes (ASI) were calculated to quantify the asymmetry magnitude in rested and fatigued states. Paired t-test was used to verify the differences between dominant and non-dominant legs in rested and fatigued states. In addition, one-way repeated measure analysis of variance was applied for comparison of ASI of both states. The level of significance was set at p < .05. Results: Passive force peak magnitude, loading rate, and impulse affecting the development of running injury were found significantly greater in dominant leg than in non-dominant leg at rested state (p < .05). However, passive force peak time and active force peak magnitude were found significantly different between legs in fatigued state (p < .05). To determine changes in percentage of asymmetry between legs in both states, ASI was used. ASI for all variables increased in fatigued state; however, no significant differences were found between both states. Conclusion: This study found that fatigue did not affect differences in vertical GRF between dominant and non-dominant legs and asymmetry changes.

• Journal of Korean Academy of Nursing
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• 제31권3호
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• pp.454-466
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• 2001

Purpose: The purpose of this study was to determine the effects of exercise program on cardiopulmonary functions and shoulder joint functioning in breast cancer patients who under- went radiation therapy after surgery. Method: Subjects in the experimental group(N=12) participated in an exercise program for eight weeks. The Exercise program consisted of shoulder stretching, arm weight training, and walking on treadmill. Maximal oxygen uptake (v2max), maximal running time, shoulder joint range of motion, and shoulder functional assessment were determined before and after the exercise program. Baseline sociodemographic and medical data were compared between experimental group and control group using the Fisher's exact test and Mann- Whitney U test. For effects of the exercise program, repeated measures ANOVA were used. Result: 1) Following the exercise program for eight weeks, both v$\alpha$ max and maximal running time tended to increase in experimental group comparing with the control group. 2) Shoulder abduction, extension and flexion of the operated upper extremity in the experimental group comparing with control significantly increased after the exercise program(p<0.05). 3) Shoulder flexion of the normal upper extremity in the experimental group comparing with control significantly increased after the exercise program(p<0.05). Conclusion: The results suggest that the exercise program for breast cancer patients undergoing radiation therapy after breast surgery can improve shoulder functions and increase cardiopulmonary functions, which are maximal oxygen uptake and maximal running time.

• Journal of the Society of Naval Architects of Korea
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• 제47권4호
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• pp.477-486
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• 2010

During sailing by wind-driven thrust on the sail, a catamaran sailing yacht generates leeway and heeling. For predicting sail force, a model test was carried out according to running attitude. Through the model test, drag and side force of the real ship was predicted. A purpose of this study is to find sail force to C.E from changed attitude during running direction. By balance of hull and sail, a heeling force of designed sail is predicted. Also through heeling force and driving force, total sail force and direction from C.E are considered with changed mast including leeway and heeling.

• Journal of the Korean Society for Railway
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• 제9권5호
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• pp.544-549
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• 2006

The characteristics of dynamic vibration are generally analyzed by an acceleration of a car body of high speed train and the acceleration can be applied to evaluation of running safety. The test of process and the analysis method about it are well explained on UIC Code 518 OR which is the spacial international standard about running safety and dynamic behavior on the line test for railway vehicle. Korean High Speed Train designed to operate at speed 350km/h has been tested on high speed line since it was developed in 2002 and it recorded the highest speed 352.4km/h at the 16th Dec. 2004 in Korea. This paper includes the analysis of running behavior of this train at speed 350km/h and the analysis of dynamic safety is presented in it, extending to the range of high speed while the UIC 518 limit the speed below 200km/h.

• Proceedings of the KSR Conference
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.1653-1661
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• 2008

A trial run of locally-developed tilting train has been in process on Chungbuk line since the test vehicle was first produced. For the system stabilization, interface verification among the systems including track, structure, catenary and signaling system, not to mention the rolling stock, is very crucial. In the area of wayside structure, the stability of track structure and train run shall be evaluated through the review of impact by increased speed by developed train on track structure. The study thus was intended to evaluate the impact on track while a tilting train is running the conventional line(ballast track), which is vulnerable to accelerated train speed. The evaluation of tilting train test running the part of Honam line was conducted to identify the impact on existing track performance by tilting train. To identify the performance of each part of track components while tilting train and high speed train were running the existing line, wheel load, rail bending stress, vertical displacement of rail and sleeper were compared so as to evaluate the expected impact by tilting train for improving the train speed.

• Steel and Composite Structures
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• 제27권2호
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• pp.161-175
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• 2018

In this study, in-situ dynamic tests of the world's longest steel box tied-arch bridge over the Yangtze River, China, are reported. The double deck bridge supports highway and monorail systems at upper and lower levels, respectively. Strain, displacement, and acceleration responses were measured and used to investigate the vibration characteristics of the bridge when excited by running trains and/or trucks at a speed of 5-60 km/h, train braking, and truck bouncing. Impact factors were correlated with the running speed of trains and trucks. A three-dimensional finite element model of the coupled monorail-train-bridge vibration system accounting for track irregularities was established to understand the system behavior and validated by the experimental results. Truck bouncing was the dominant impact factor on bridge responses. The running speed of vehicles determined the riding comfort of traveling trains.

• Journal of Ocean Engineering and Technology
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• 제23권4호
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• pp.38-46
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• 2009

Two sets of numerical simulations were carried out for a planing hull model ship. In the first, the WAVIS 1.4 linear and nonlinear potential solver was utilized with the free support condition, in which the running posture was determined during calculation. The linear and nonlinear potential calculation results showed qualitative agreement in the trim and resistance coefficient with the MOERI towing tank test. However, the nonlinear potential calculation gave better results than the linear method. In the next simulation, Fluent 6.3.26 with a VOF model and the WAVIS 1.4 nonlinear potential solver were used with the given running posture from the measurement carried out in the MOERI towing tank. Fluent with the VOF method had substantially better agreement with model test results than the results from the WAVIS nonlinear potential calculation for the total resistance coefficient, and for the bow and stern wave patterns, in spite of the much greater computational costs. Both methods can be utilized in planing hull design when their limitations are perceived, and the running posture should be predicted correctly.