• Journal of Korean Society of Transportation
• /
• v.18 no.1
• /
• pp.35-43
• /
• 2000

The Purpose of this Paper was to study the relationship between the change of operating speeds and the accidents on horizontal curves. For this purpose, we divided a horizontal curve section into two parts, a tangent section and a curve section, to estimate the operating speed for each vehicle. For studying relationship between the change of speed and geometric effect, the free-flow speed was used. The location and speed for the lowest speed were studied. Also, we analyzed the relationship between the change of operating speeds and the accidents. The followings are resulted in this study. First, drivers tend to reduce speeds significantly before they reach a curve. And the lowest speed was recorded at the downstream of the Point of curve (PC) due to the limited sight-distance of drivers on curve. Second, the larger the change of operating speeds become, the greater frequency of accident was recorded. These results can be used for developing the safety index on highways to check the design consistency.

• The Journal of Fisheries Business Administration
• /
• v.36 no.3 s.69
• /
• pp.65-88
• /
• 2005

The fisheries industry has been changed drastically during the so - called Golden Growth Era of Korea. Recently, WTO/DDA agenda drove industries out of their safe refuges toward infinite competitions in the world. This paper aims at finding out distinguished features in the structural changes of fisheries since 70s. Furthermore, policy implications are investigated in order for the fisheries to survive in the outdoors. The paper consists of the following sections. First, we consider why and for what the structural change of fisheries in historical perspective should be investigated. And we introduce how we can approach to the goal in various aspects in the second section. In the third section, we examine the historical change of Korean fisheries in respect of national economy, resource allocation mechanism, industrial structure, and fisheries society. In the fourth section, we extract the development steps in fisheries from the periodic characteristics, using various methods of the above approaches. And we deduce the next step for Korean fisheries in the future. Finally, we conclude that there needs some turning point of fisheries policies in Korea, striving to foster the fisheries industry in the future. As results of empirical analysis in this paper, we find that fisheries industry in Korea has experienced some momentous changes during 30 years, using I/O data of B.O.K. The weight of fisheries sector in the whole economy of Korea increased during early 70s, initially leading the national economy to export - oriented engine for growth. But fisheries sector has shrunk rapidly since late 70s. Almost resources in Korea were allocated to expanding manufacturing industries. Further, fisheries industry has encountered perfect international competitions since the late 90s. This paper draws that fisheries industry in Korea will jump across to next step of qualitative growth in the future. Therefore, we recommend that the policies should be focused on enhancing the industrial competitiveness, switching quantitative growth to qualitative advance in fisheries.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2008.11a
• /
• pp.348-353
• /
• 2008

A vibration analysis for a rotating cantilever beam with the tapered cross section is presented in this study. The stiffness changes due to the stretching caused by centrifugal inertia forces when a tapered cantilever beam rotates about the axis perpendicular to its longitudinal axis. When the cross section of cantilever beam are assumed to decrease constantly, the mass and stiffness also change according to the variation of the thickness and width ratio of a tapered cantilever beam. Such phenomena result in variations of natural frequencies and mode shapes. Therefore it is important to the equations of motion in order to be obtained accurate predictions of these variations. The equations of motion of a rotating tapered cantilever beam are derived by using hybrid deformation variable modeling method and numerical results are obtained along with the angular velocity and the thickness and width ratio.

• Steel and Composite Structures
• /
• v.28 no.4
• /
• pp.403-414
• /
• 2018

In this paper, the lateral-torsional buckling of axially-transversally functionally graded tapered beam is investigated. The structure cross-section is assumed to be symmetric I-section, and it is continuously laterally supported by torsional springs through the length. In addition, the height of cross-section varies linearly throughout the length of structure. The proposed formulation is obtained for the case that the elastic and shear modulus change as a power function along the beam length and section height. This structure carries two concentrated moments at the ends. In this study, the lateral displacement and twisting angle relation of the beam are defined by sinusoidal series. After establishing the eigenvalue equation of unknown constants, the beam critical bending moment is found. To validate the accuracy and correctness of results, several numerical examples are solved.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.19 no.4
• /
• pp.363-369
• /
• 2009

A vibration analysis for a rotating cantilever beam with the tapered cross section is presented in this study. The stiffness changes due to the stretching caused by centrifugal inertia forces when a tapered cantilever beam rotates about the axis perpendicular to its longitudinal axis. When the cross section of cantilever beam are assumed to decrease constantly, the mass and stiffness also change according to the variation of the thickness and width ratio of a tapered cantilever beam. Such phenomena result in variations of natural frequencies and mode shapes. Therefore it is important to the equations of motion in order to be obtained accurate predictions of these variations. The equations of motion of a rotating tapered cantilever beam are derived by using hybrid deformation variable modeling method and numerical results are obtained along with the angular velocity and the thickness and width ratio.

• Advances in aircraft and spacecraft science
• /
• v.2 no.4
• /
• pp.391-401
• /
• 2015

Crashworthiness design and certification have been and will continue to be the main concern in aviation safety. The effects of roll angles on fuselage section crashworthiness for typical civil transport category aircrafts were investigated. A fuselage section with waved-plates under cargo floor is suggested, and the finite element model of fuselage section is developed to simulate drop test subjected to 7 m/s impact velocity under conditions of 0-deg, 5-deg, 10-deg and 15-deg roll angles, respectively. A comparative analysis of failure modes, acceleration responses, and energy absorption of fuselage section under various conditions are given. The results show that the change of roll angles will significantly affect fuselage deformation, seat peak overloads, and energy absorption. The crashworthiness capability of aircraft can be effectively improved by choosing appropriate landing way.

• Journal of Korea Foundry Society
• /
• v.7 no.1
• /
• pp.28-37
• /
• 1987

The progression of the solidification wave front in V-section and finned casting was studied by use of the pour-out test, employed with high. Purity aluminum. The results obtained were as follows; a) The shape of solidification wave front at the inside and outside corners did not change according to solidification time, but it changes according to the corner angles at a given molding and melting condition. b) The cooling fin effect could be repserented as functions of solidification time and fin sise, and this result could be applied to enhance the accuracy of the section modulus method in the design of T and V section.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.60 no.3
• /
• pp.669-673
• /
• 2011

This study explores the numerical analysis method of fluid dynamics in the reaction section to improve the gas processing efficiency in the hazardous gas removal by atmospheric thermal plasma. This study also intends to contribute in technology advance to improve the processing efficiency and make the process more stable. Numerical analysis of temperature distribution in the reaction section dependent on the change in flow velocity of Ar and plasma temperature change, which are major control variables in the cracking process of HFC-23 using arc plasma, was done. The characteristic of incoming oxygen by temperature suggested that when temperature increased to 1600K, 1700K, 1800K respectively, the range of cracking temperature 1500K increased to 75.0%, 83.3%, 90.2% respectively. The temperature change of Ar by velocity change was widest in the area higher than 1500K when the velocity was 2.5m/s; however, since there was no big difference when the velocity was 2m/s, it is believed that 2 m/s would be most proper.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.8 no.1
• /
• pp.103-108
• /
• 2008

Riverbed change is greatly influenced by artificial factors such as dam construction, gravel collection, and river improvement. This study simulated a long-term bed change based on the GSTARS3 model using actual data from the area downstream of the Geum River Daecheong Dam and compared the estimation with a section of the actual measurement. As a result, it was found that the section of the actual measurement was far lower than the result of the simulation in terms of long-term bed change. While the area downstream of Daecheong Dam displayed approximately an average of 2.29 m of streambed degradation on average while the upper stream area showed approximately 0.63 m of bed degradation over 24 years. In the simulation of the area downstream of Daecheong Dam based on the GSTARS3 model, similar bed degradation was observed. However, a great difference was detected between the result and the actual measurement. According to the cause analysis, the riverbed in the area downstream of Daecheong Dam has continuously degraded due to the dam construction and mass collection of gravel. The mass collection of gravel was the main cause of riverbed change. It was found that about 76% of all riverbed degradation was caused by the mass collection of gravel.

• Journal of the Korean Home Economics Association
• /
• v.35 no.4
• /
• pp.79-94
• /
• 1997

This study was performed to develop a basic stacks pattern for middle-aged women reflecting the characteristics of their lower body types. Anthropometric measurements using sliding guage method were carried out for 4 women 40's For the analysis of the lower body types horizontal and vertical section maps obtained by sliding gauge method and 2 indices were produced. Based on the slacks construction components produced by the drafts of their lower body surface experimental slacks pattern was designed. Multiple comparison test was used to compare 3 existing slacks patterns with the experimental pattern. 1. The results of the body section map analysis were as follows: 1) In the frontal view silhouette of vertical section maps there were less individual differences in items with skeleton landmarks than those without them. 2) In the shape of horizontal section maps waist section represented more round shape than the others and thigh maximum width section had the flattest shape. Flat ratios(depth/width) of subjects were much higer than those of young women which clarified the change of depth was bigger than that of width with aging process. 2. The slacks construction components for pattern drafting were as follows: 1)Ease amount of waist was 0.5cm and front and back waist girth difference was 1.2cm Ease amount of hip was 1,8cm and front and back hip girth difference was 0.7 cm 2) The amount of dart intake incresed in the order of side(4cm) back(3,6cm) from (2.8cm) The length of dart leg incresed in the order of front side back.