• Proceedings of the KSRS Conference
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• v.2
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• pp.563-566
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• 2006

In order for the evaluation and analysis of the spring drought which has been periodically occurring in Korean peninsula since 2000, the use of satellite image data is increasing to investigate temporal and spatial characteristics of the drought areas. The recent spring droughts in south Korea have some characteristics. It last for short period in spring when the activity of vegetation is not lively and it have large areal deviation in the severity of drought. In this study, considering the characteristics of the spring drought in Korean peninsular, the MODIS satellite image data which has superior spatial and radiometric resolutions was used for the analysis of the spring drought. In two basins having different spatial characteristics, the drought events were selected and their severities were analyzed using the MODIS NDVI, LSWI, and daily rainfall data since 2000, and the spatial characteristics of the drought area were analyzed using the DEM, land cover, and digital forest map of the study areas.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.1
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• pp.52-61
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• 2009

This experiment was conducted in attempt of improving hydrodynamic efficiency of the propulsion mechanism by installing a spring to the wing so that the opening angle of the wing in one stroke can be changed automatically, compared to the existing method of fixed maximum opening angle in Weis-Fogh type ship propulsion mechanism. Average thrust coefficient was almost fixed with all velocity ratio with the prototype, but with the spring type, thrust coefficient increased sharply as velocity ratio increased. Average propulsive efficiency was larger with bigger opening angle in the prototype, but in the spring type, the one with smaller spring coefficient had larger value. In the range over 1.0 in velocity ratio where big thrust can be generated, spring type had more than twice of propulsive efficiency increase compared to the prototype.

• Transactions of Materials Processing
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• v.20 no.6
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• pp.456-460
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• 2011

A major source of difficulty in die design for high strength steel is the high level of elastic recovery during unloading. The degree of elastic recovery is affected by factors such as material strength, bending angle, punch's corner radius and sheet thickness. Finite Element Method was used in the present work to quantitatively analyze the elastic recovery for various combinations of these parameters. In some cases elastic recovery happened in reverse direction. This phenomenon, which we call spring-go, was explained via changes in stress distribution in the panel occurring in the forming process.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.942-945
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• 2002

A garter spring, which is a long. special, close-coiled extension spring with its ends joined to form a ring, is used in connection between vacuum circuit breaker and bus bar in switchgear. To carry short-time current and resist welding at the contact surface in the connection, the garter spring must transmits an uniform contact force to the contact surface through the contact chips arranged in the circumference of bus bar. In this paper, the system for measurement of the contact force by the garter spring is developed. Using the developed measurement system, the design of the connection structure including the garter spring is reviewed to obtain the uniform contact forces in all of contact chips.

• Structural Engineering and Mechanics
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• v.65 no.4
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• pp.447-452
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• 2018

The controlling and prediction of spring back is one of the most important factors in sheet metal forming processes which require high dimensional precision. The relationship between effective parameters and spring back phenomenon is highly nonlinear and complicated. Moreover, the objective function is implicit with regard to the design variables. In this paper, first the influence of some effective factors on spring back in U-die bending process was studied through some experiments and then regarding the robustness of artificial neural network (ANN) approach in predicting objectives in mentioned kind of problems, ANN was used to estimate a prediction model of spring back. Eventually, the spring back angle was optimized using the Imperialist Competitive Algorithm (ICA). The results showed that the employment of ANN provides us with less complicated and time-consuming analytical calculations as well as good results with reasonable accuracy.

• Journal of the Korean Home Economics Association
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• v.30 no.4
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• pp.15-26
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• 1992

To investigate the seasonal effects on physiological responses of human body, clothing micro-climate, and subjective sensation, selected the cloths the most frequently dressed by men in spring and fall, and completed wearing trials in the climatic chamber. The results are as follows: 1. Rectal temp. ranged 36.8-37.1$^{\circ}C$ in either spring or fall, and no seasonal effect was found. 2. In skin temp., there was no seasonal effect in forehead, abdomen, and forearm. Skin temp. of chest was higher in spring than in fall. On the contrary, reverse was true in high and leg. Average skin temp. ranged 32.2-33.2$^{\circ}C$ in spring and 32.9-34.$0^{\circ}C$ in fall. 3. Average total sweat rate of spring, 79.4g/hr, was smaller than that of fall, 110.9g/hr. 4. Clothing temp. ranged 28.1-32.8$^{\circ}C$ in spring and 27.6-31.$0^{\circ}C$ in fall. Clothing humidity ranged 36.9-48.9% in spring and 38.2-51.1% in fall. Therefore, clothing microclimate was higher during fall than during spring. As results, skin temp. of the body core except chest did not show seasonal variation, but there was obvious seasonal variation in skin temp. of the extremities. Therefore, seasonal variation should be take into consideration in the experiments related to the cloth. In addition, standard for each season and the degree of work performance should be re-established in clothing micro-climate.

• Journal of the Korean Institute of Landscape Architecture
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• v.34 no.5 s.118
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• pp.24-31
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• 2006

The tourism sites and attractions of South Korea in many ways have little specialties in their image due to the local development plan's uniformed way of designing and improving landscape. The lack of specialties in tourist sites and attractions have caused displeasure from the local residents, as the sites don't characterize the locals as attractively and appealingly as is the potential. There have been no research or studies on the scenic effect on tourism or resort development thus producing an urgent call for local authorities to develop planned landscapes of local sites. This study compares Bugok Onchon (hot spring), whose image hardly differentiates itself from the others, with Kinosaki Onsen (hot spring). Bugok Hot Spring, which is the case study of this report, has recorded a steady decline of visitors due to a result of uniformed development planning. In the case of Kinosaki Hot Spring, scenery development, however, has made a breakthrough in tourist increase despite its no-so-easily-accessible location. The study assumes that scenery effects changes in promoting local tourism, thus analyzing and comparing the two hot springs to unearth critical factors in tourist site development, as well as viewing the present state of Bugok Hot Spring for further study. Furthermore, the study provides tourist site developers with a guideline of the two comparative Hot Spring cases. Investigations and analyses are mainly focused on colors, which are important factors in making underlying images of tourist sites, and the comparison of Bugok Hot Spring with Kinosaki Hot Suing. Bugok Hot Spring shows the influences of accent colors as well as a variety of color combinations and similarities of color tones. Kinosaki Hot Spring shows a combination of naturally-generated colors its own scenic beauty by trimming the landscape. Through the comparative study of the two hot springs, Bugok (boulevard) uncovers a typical case of Korean local landscape planning, even with the well-known tourist attraction 'Bugok-Hawaii', and calls upon a new, serious landscape-improvement plan to increase visitors.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.3
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• pp.202-209
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• 2003

A simply supported beam subjected to a uniformly distributed tangential follower force and the two successively moving spring-mass systems upon it constitute this vibration system. The influences of the velocities of the moving spring-mass system, the distance between two successively moving spring-mass systems and the uniformly distributed tangential follower force have been studied on the dynamic behavior of a simply supported beam by numerical method. The uniformly distributed tangential follower force is considered within its critical value of a simply supported beam without two successively moving spring-mass systems, and three kinds of constant velocities and constant initial displacement of two successively moving spring-mass systems are also chosen. Their coupling effects on the transverse vibration of the simply supported beam are inspected too. In this study the simply supported beam is deflected with small vibration proportional to natural frequency of the moving spring-mass systems. According to the increasing of initial displacement of the moving spring-mass systems the amplitude of the small vibration of the simply supported beam is increased due to the spring force. The velocity of the moving spring-mass system more affect on the transverse deflection of simply supported beam than other factors of the system and the effect is dominant at high velocity of the moving spring-mass systems.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.2
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• pp.247-254
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• 2003

The paper presents the influence of spring dynamics and friction on dynamic responses in a spring-driven cam system. The characteristics of the friction on the camshaft are analyzed using the nonlinear pendulum experiment while the parameters of the friction model are estimated using the optimization technique. The analysis reveals that the friction of the camshaft depends on stick-slip, Stribeck effect and viscous damping. Spring elements are found to have much influence on the dynamic characteristics. Hence, they are modeled as four-degree-of-freedom lumped masses with equivalent springs. The appropriateness of the derived friction model and spring model is verified by its application to a vacuum circuit breaker mechanism of the cam-follower type.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.2236-2241
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• 2008

To predict the dynamic behaviour of railway vehicle, the complex vehicle structure has been described by mathmatical model such as mass, spring and damper. Air-spring has played a major role to improve dynamic characteristics, vibration isolation and ride comfort. The mechanical behaviour of air spring is very complicated. The behaviour is based on fluid and thermodynamic mechanisms. The main parameters of air spring are stiffness due to compression of the air in the spring and surge reservoir, change of area stiffness and orifice damping. In this paper, we have studied an air-spring modeling method and compared the difference between calculation and test.