• Journal of the Korean Institute of Navigation
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• v.20 no.4
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• pp.81-98
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• 1996

The purpose of this study was analysis of the muscle action in physical exercise in the rolling machine. The rolling machine moved by eletric power-driven was made to keep the constant cycle and size of rolling. The subjects of this study consist of 4 seaman(SM) and 4 landman (LM). The experiment analyzed the muscle power of lower and upper limbs by Intergrated Electromyogram(IEMG). The measurement was made on the ground, and 6 and 8 degrees of rolling separately. This study concludes as follows ; including analysis of IEMG of heavy exercise in two hands curl, a standstill walking and just standing. 1. IEMG of the lower limbs when standing. 1) In 6 degrees of rolling, for the landman(LM), vastus medialis m.(9.73), vastus lateralis m.(9.55), and rectus femores m.(8.73) acted more. As for the seaman(SM), tibialis anterior m.(5.38), biceps femores m.(5.05), and gastrocnemius m.(4.47) acted more. 2) In 8 degrees of rolling, in common, for both LM and SM, it were vastus medialis m.(11.20 and 8.97), vastus lateralis m.(16.20 and 4.63), and tibialis anterior m.(5.13 and 4.47). 3) It was showed that IEMG of LM was larger than that of SM. 2. IEMG of the lower limbs when walking. 1) On the ground, for the LM, gastrocnemius m.(7.08), vastus medialis m.(6.65), and vastus latralis m.(6.60) acted more. As for the SM, vastus lateralis m.(7.08), vastus medialis m.(6.58) and restus femores m.(5.10) acted more. 2) In both 8 and 6 degrees of rolling, vastus medials m.(14.50 and 11.98), vastus lateralis m.(10.10 and 14.10), and gastrocnemius m.(11.75 and 7.10) acted more in two groups. 3) It was showed that IEMG of LM was larger than that of SM. 3. IEMG of the lower limbs when heavy exercise(two hands curl). 1) On the ground, for the LM, vastus lateralis m.(21.68), vastus medialis m.(16.08), and rectus femores m.(14.08) acted more. As for the SM, tibialis anterior m.(16.08), vastus medialis m.(14.58), and vastus lateralis m.(8.78) acted more. 2) In 8 and 6 dgrees of rolling, it were vastus medialis m.(17.05 and 12.45), vastus lateralis m.(37.98 and 17.08), and tibialis anterior m.(19.83 and 13.20). 3) It was showed that IEMG of LM was larger than that of SM. 4. IEMG of the upper limbs when heavy exercise. 1) On the ground, the brachialis m.(44.30 and 17.80), and biceps brachii m.(13.40 and 25.10) acted more in two groups. 2) In both 6 and 8 degrees of rolling, the brachialis m.(37.60 and 24.35), and biceps brachii m.(11.38 and 7.97) acted more in two groups. 3) It was showed that IEMG of SM was larger than that of LM.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.559-560
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• 2006

Powder forging is used for heavy-loaded parts (rings of rolling-contact bearings, gears etc.) production. Rolling contact fatigue is material property values of which characterize possibility of practical utilization of such parts. Rolling contact fatigue of some steels obtained out of prealloyed powders Astaloy CrM, Atomet 4601, Atomet 4901 and powder blends iron-carbon-nickel by hot forging is studied in the present paper. Effect of various kinds of heat and thermomechanical treatment on rolling contact fatigue is determined. Thermomechanical treatment provides optimal values of rolling contact fatigue. In this case steel structure contains up to 40% of retained metastable austenite which is transformed to martensite on trials. Thus typically crack is generated on residual pores and non-metallic inclusions instead of martensite zones in wrought steels.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.04a
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• pp.62-64
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• 2009

Control of back-up roll deformation and wear profile in plate rolling is important not only for enhancement of the structural precision of mill, but also for improving the yield and rolling operation. in the heavy plate mill, there have been strong demands for upgrading back up roll operation technology. In order to satisfy these demands, it is essential to develop the backup roll deformation analysis models and wear profile prediction models. This paper gives a general description of the backup roll deformation and wear model, simulation result for deformation analysis and wear profile.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1301-1307
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• 2008

The Seoul-Metro is the first city railroad corporation to operate RIMS(Rolling-stock Information Maintenance System). The development of "RIMS Project" and trial running task were started from Mar 29, 2001. Finally, this project was completed successfully on Dec 31, 2005, as integrated systems including light or heavy maintenance works in Ji-Chuk and Chang-Dong Rolling-stock Offices. After that, from 2006 to Dec 31, 2007, we promoted a this new program to other four rolling-stock offices (Su-Seo, Gun-Ja, Sin-Jeong) and the headquarter. For the duration of trial running, we developed and applied new complementary program having made up for the weak points or defects. The series of new program which were newly developed and applied are comprised of an operation management, trouble management, wheel management, heavy maintenance table automatic creation programs and ordering prediction programs to purchase goods smoothly. The Seoul-Metro have registered these programs(RIMS) to Computer Program Protection Committee. We'd like to introduce a composition of program for enhancement of a city railroad Information Systems.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.91-92
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• 2007

Control of crown and flatness in plate rolling is important not only for enhancement of the structural precision of products, but also for improving the yield and rolling operation. In the heavy plate mill, there have been strong demands for upgrading plate crown and flatness. In order to satisfy these demands, it is essential to develop the high precision numerical models. This paper gives a general description of the crown and flatness preset control model, work roll bender system, simulation result for shape control.

• Transactions of Materials Processing
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• v.11 no.1
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• pp.24-35
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• 2002

Recent trend and future prospect of flat rolling of steel has been summarized based on the earlier reports. Key technology in the plate rolling is to have ultra fine microstructure having high resistance against crack propagation during application. Heavy accelerated cooling facility and high power rolling mill will be helpful to develope the high toughness steel. Precise modeling of properly prediction based on deformation and transformation imposed on microstructure of steel during processing is highly anticipated. For the hot strip rolling process, new trend is lies on the production of ultra-thin gauged hot strip to substitute cold rolled strip. For the substitution of cold rolled strip into hot rolled strip widely, high formable property of hot strip is highly required. For the formabilit, the ferritic rolling of extra low carbon steel under high lubricated condition is essential. Recently introduced semi-continuous thin slab and rolling mill line is very plausible to develope those kinds of products easily In the view groin facility combination. New idea to modify the existing continuous hot strip mill line to produce the ultra thin-gauged hot strip in an economic way is suggested in this report.

• Journal of the Korean Institute of Navigation
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• v.13 no.2
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• pp.23-36
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• 1989

Marine casualities in the high sea are mainly classified into the breakage of hull and capsize , of which the latter occurs frequently to a small craft and container vessels by extreme rolling. The aim of this study is to develop shiphandling techniques for the prevention of ship's large rolling by way of evaluating dangerous degree of rolling in heavy weather. In this study, rolling motion is analized by using statistical method as follow : (1) 8 sample ships is presented for calculation. (2) Analized sea state are Beaufort scale 7 and 10 (wind velocity 30kts and 50kts respectively) and significant wave height is put as 5.2m and 11.2m. (3) The formula recommended by International Towing Tank Conference (ITTC) is used to calculated the wave spectrum. The results of this study are as follow : The results of this study are as follow : (1) Most of the vessels with beam of 20 meters or less was found to be capized in the waves abeam under the sea condition of Bearfort scale7(30kts). (2) For the vessels range 20m to 30m was found safe under the sea conditions of Bearfort scale 7(30kts) and imminent danger under the sea condition of Beaufort scale 11(50kts). (3) It is proved that any vessel could be capsized by heavy rolling regardless of vessel's size whenever the motion is synchronized with waves abeam. This study concludes that the navigator, especially at night , must anticipate the exact wave direction, referring to the wether report and coastaline, not to lay the vessel in the serial wave abeam.

• Journal of the Korean Society for Railway
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• v.14 no.4
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• pp.333-340
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• 2011

The purpose of this paper is to develop two kinds of finite element models for the heavy deformable obstacle defined in grade crossing collision scenario of the Europe TSI and the Korean rolling stock safety regulations and to apply the crashworthiness evaluation for the Korean high-speed EMU with the FE model. The numerical models of the heavy obstacle were changed from a past rigid one to a current deformable one whose stiffness requirement should be verified by a collision simulation defined in the regulations. Through several trial simulations, two types of numerical models for the heavy obstacle were developed, which satisfied physical properties specifies in the regulations. One is a solid-type obstacle with uniform density and the other is a shell-type. With the obstacles developed in this study, the grade crossing collision scenario for Korean high-speed EMU was simulated and evaluated for the two-type obstacle models. From the simulation results, the shell and solid-type obstacles showed quite different behaviors after collision, and the shell type model gave more severe results.

• Journal of the Korean Society for Railway
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• v.6 no.1
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• pp.41-48
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• 2003

Most of people spends their times in indoor about 85% of a day. Thus, indoor is more serious than outdoor concerned with the health. We discussed comfortableness in a railroad electric rolling stock, and focused on temperature and humidity. Electric rolling stock is one of major public transportation system because of an increasing in population and heavy traffic problems. The passengers are under the influence of indoor air quality such as air temperature, relative humidity and air velocity. Ventilation system in electric rolling stock should be designed for the health and comfort. One of the main aims is to create an acceptable thermal environment without draught problem. The draught sensation increases when the air temperature decreases and the air velocity increases. Airflow in electric rolling stork is turbulent. Temperature and humidity gradients in electric rolling stock have been studied. And, the difference between mean temperature and rotative humidity measured at 0.7, 0.9, 1.2, 1.7m above the floor. It has been found that temperature and relative humidity with large fluctuations caused more draught complaints.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.5
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• pp.380-387
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• 2016

Present research target to develop the procedure of long-term fatigue analysis of the structural details near the upper rolling chock of IMO type B tank by using the time domain modal analysis technique where both the contact and friction behavior can be accurately simulated. In order to perform the time domain analysis focused on the contact and friction, the entire model of the hull and tank was condensed with DOF reduction technique, which is obtained by transforming the global finite element model into its quasi-static modal coordinate. Modal analysis using the quasi-static deformation modes is chosen as a cost effective time domain simulation method and this is based on the fact that the structural response of the tank is quasi-static. Based on the developed cost effective time domain simulation method, the long-term fatigue analysis procedure for the structural details near the rolling chock and key of independent type tank is targeted to be established. The developed fatigue assessment procedure takes into account, wave induced stress and both contact and friction induced stress without loss of accuracy.