• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.05a
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• pp.245-250
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• 2003

Hull form development and Anti-rolling tank of G/T 360ton class fishery patrol ship was carried out in the CWC at Chosun university, cooperatively with WJFEL(The West Japan Fluid Engineering Laboratory). Same size of 15 knots class fishery patrol ship was selected as a parent form(Model number: CU-015), and modified fore and after body hull form under the slightly lengthened to be suitable for the operation at 20 knots. This paper investigated for a rolling performance and an effective using method when fishery patrol ship was equipped with anti-rolling tank. On several occasions of rolling test was made reference to design data of a similar ship. Although the hull form was highly constrained in being limited to modification of a parent hull form, significant wave resistance improvement was made.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.355-360
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• 2005

This paper describes how to measure the running safety using vibration accelerometers theoretically, and considers the effect of vibration parameters, such as amplitude and period, on the running safety by numerical analysis, which shows that the running safety are decreased as those parameters are increased.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1412-1417
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• 2011

Safety is soaring up as a core value in accordance with the recent improvement of operating speed & incidents. rolling stock is a kind of system which works together with several components. one component has an effect on the sub-system, which can cause to the train safety operation, therefore reliability management of the major components of rolling stock is a kind of solution to the safety operation of train, but realistically maintenance in korea performed based on period rather than TBO of major components, but Japan does new maintenance system based on the major components, which optimizes maintenance tasks. actually Japan can apply to new maintenance system because they are ready in planning step but in this study, making a reliability data of major components and review the adaptability of new maintenance system to the rolling stock operating in Ansan line.

• Journal of the Korean Operations Research and Management Science Society
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• v.14 no.2
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• pp.67-74
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• 1989

This paper considers single-product production and inventory management problem where cumulative demands up to each time period are mutually independent random variables(known) having continuous probability distributions and the associated cost-minimizing production schedule (when to produce and how much to produce) need be determined in rolling horizon environment. For the problem, both the production cost and the inventory holding and backlogging costs are included in the whole system cost. The probability distributions of these costs are expressed in terms of random demands, and utilized to exploit a solution procedure for a production schedule which minimizes the expected unit time system cost and also reduces the probability of rist that, for the first-period of each production cycle (rolling horizon), the cost of the "production" option will exceed that of the "non-production" one. Numerical examples are presented for the solution procedure illustration.cedure illustration.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.158-166
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• 2007

After constructing the high-speed railroad, KORAIL acquired advanced maintenance techniques about Rolling-stocks. Also RCM theory is applied to maintenance field like as inspection period and method. In the meantime, the development of the maintenance methode for Rolling-stock is slow when it compares to the components and system technology. For this reason KORAIL tries to build the optimal maintenance system which can lead the Rolling-stock maintenance technique. The existing vehicle except High Speed train KTX are separated to electric motor car, electric locomotive, diesel locomotive, diesel car, passenger car and freight car. The inspection period and methode for existing vehicles which mentioned above will be examined and the optimal Rolling-stock maintenance technique will be applied.

• Journal of the Korean Society for Railway
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• v.13 no.3
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• pp.251-256
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• 2010

By legislating safety regulations for design, manufacturing and operation of rolling stock through rolling stock safety law, diverse of safety requirements have been established. On the other hands, differences of technical level in practical circumstances between domestic and overseas are pointed out that not be able to be overcome in short period. About collision safety requirements for rolling stock, European countries have been applying TSI requirement to all of rolling stock and domestic collision safety requirements in rolling stock safety law are based on TSI. In following thesis, it is showing an analysis simulation for current rubber cushion and hydraulic buffer system to verify if they are fit to collision safety requirements and result of the simulation program for prior verification. This also suggests a method to prove the performances of coupler system for future.

• Journal of the Korean Institute of Navigation
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• v.3 no.1
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• pp.19-28
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• 1979

There are two different assertions on the rolling error in the solid-controlled gyro compass which contains two rotors in its inner gyro sphere. One assertion is that there is a rolling error and the other is that there is no rolling error. This paper examines the rolling error caused by the centrifugal force by the experiment to reveal that the first assertionis reasonable, and it also attempts to explain qualitatively how the rolling error occurs. The Hokushin-Plath gyro compass is chosen as a model. The rolling error is examined by the swing test in various periods. From the tests, the following results are obtained. As long as the swing is continued under the fixed condition of the ship's heading, the swinging period and the amplitude, no error appears. In case the gyro compass is affected by the swingings except those of the cardinal planes, the error starts to appear only after the swing is finished and it is increasing slowly. It takes about 20 minutes for the error to reach its maximum value. The type of this error is a quadrantal one which makes the ship's heading high in the first and third quarters and low in the second and fourth quarters. But in each case the experimental maximum error is greater than the theorectical one.

• Transactions of Materials Processing
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• v.4 no.4
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• pp.375-389
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• 1995

In H shape rolling, accurate predictions of deformation and temperature distribution in a billet are quite important because they are the main factors in determining roll calibers and roll pass schedules. Many researches have been performed to achieve the predictions, but most of them are limited to single pass or isothermal assumptions. In the present investigation, it is attempted to develop a method to predict the deformation and temperature distributions which is applicable to a complete rolling process that usually consists of several rollings under different rolls for a period of time. The method works by coupling two analyses : one is an approximate analysis for temperature distribution prediction and the other is the slab-FEM hybrid analysis for deformation prediction. The method is applied to analyze a "H" shape rolling process consisting of nine passes under four different rolls. In the present paper, basic ideas of the method are presented. Also, shapes of cross sections, strain and temperature distributions, roll separating force and roll torque predicted by the method are discussed.

• Journal of the Korean Society for Railway
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• v.9 no.5 s.36
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• pp.555-560
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• 2006

This study finds out and suggests success factors for the application of RIMS project through the case study of Seoul Metro and literature survey. The successful application of RIMS needs expert knowledge and concept of BOM, standardization of maintenance planning, check lists of heavy maintenance inspection, organization structure of rolling stock maintenance offices, material management system of warehousing and the process of parts repairing between offices, connection of material ordering system, problem solving of circular spare parts administration among inspection, maintenance, and material organizational units, systemic serial number management of parts with RFID, daily closing diary connected with work process chart, and sufficient period of RIMS's test run. RIMS contributes to real time management of rolling stock maintenance, transparency of management, reliability of train operation, customer satisfaction, and management innovation.

• Journal of dental hygiene science
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• v.17 no.3
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• pp.267-274
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• 2017

This study aimed to compare the effectiveness of chewable toothbrush and manual toothbrush and provide basic data for recommendation of the chewable toothbrush in specific groups and situations. A total of 20 subjects participated in this study (rolling method, 10; non-rolling method, 10). After professional prophylaxis, participants used the manual toothbrush to brush their teeth for 3 minutes. After a 7-day wash-out period, participants used the chewable toothbrush according to the manufacturer's instructions. Pre- and post-plaque indexing of the teeth was performed. The dental plaque index was assessed using the Turesky Modification of the Quigley-Hein Plaque Index (TMQHPI) for amount of plaque and Silness-Loe Plaque Index (SLPI) for plaque thickness. The difference between pre- and post-dental plaque index was analyzed using a paired t-test and the Wilcoxon signed-rank test. The Mann-Whitney U test was also used to compare the dental plaque index reduction rates. The dental plaque index differed significantly between the chewable toothbrush and the manual toothbrush. The TMQHPI reduction rate was significantly different between the rolling and non-rolling method groups for the manual toothbrush but not the chewable toothbrush. The difference in SLPI reduction rate between the rolling and non-rolling method groups was significant for the manual toothbrush but not for the chewable toothbrush. Differences in the dental plaque index reduction rates between the chewable and manual toothbrushes were not significant in the non-rolling method group. The results of this study showed higher reduction rates in dental plaque with manual toothbrush use than with chewable toothbrush use. However, the non-rolling method group did not show statistically significant differences according to toothbrush type. The present study showed that a chewable toothbrush can be an alternative to a manual toothbrush for individuals who have difficulty using the generally recommended rolling method.