• Journal of Institute of Control, Robotics and Systems
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• v.7 no.5
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• pp.432-437
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• 2001

Korea High Speed Train(KHST) is supposed to run up 350km/h, in which the braking system has a crucial role for the safety of the train. In the design st데 of the braking system, its very hard to ac-quire information data for design guidelines. A HILS(Hardware-In-the-Loop Simulation) system can be used to get design data which could simulate the braking system of the real train in real-time. In this paper, cars are modelled including car dynamics, brake blending algorithms, pneumatic actuator dynamics, the models of each braking devices, adhesive coefficients, and soon. Real-time braking time, distance, and other design parameters are simulated using a DSP board and C language which shows the validity of the proposed method.

• Safety and Health at Work
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• v.8 no.1
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• pp.36-41
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• 2017

Background: Police work is generally sedentary although there may be situations that require physical endurance and strength, such as foot chases and arresting suspects. Factors such as excessive body fat can impede an officer's physical ability to deal with such occurrences. Our objective was to examine associations between officers' body fat percentage (BF%) and performance on a standardized fitness protocol. Methods: Data were obtained from fitness screening among 1,826 male and 115 female officers in a large US police agency. The screening consisted of a 2.4-km run, push-ups, sit-ups, and sit-and-reach test. Sex-specific body fat percentages were estimated from skinfold thickness measured using calipers. Linear regression models were used to examine unadjusted and adjusted mean scores of fitness tests across BF% tertiles. Results: The prevalence of overall fitness was 4.3 times greater in male officers and 3.6 times greater in female officers having the lowest BF% tertile compared with the highest tertile (30.3% vs 7.1% and 46.0% vs 12.8%, respectively). BF% was linearly and positively associated with the time of 2.4-km run (p < 0.001), and linearly and inversely associated with the number of push-ups (p < 0.001), sit-ups (p < 0.001), and the distance of sit-and-reach (p < 0.001) in men. Similar associations were observed in women with the exception of sit-and-reach (p = 0.122). Associations were independent of age, race/ethnicity, rank, and duty station. Conclusion: Overall, BF% was inversely associated with fitness levels in male and female officers. Future longitudinal studies should be initiated to explore the potentially causal relationship between BF% and fitness in law enforcement officers.

• Journal of the Korean Society of Marine Environment & Safety
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• v.1 no.1
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• pp.63-82
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• 1995

In recent years, through the rapid development in personal computer technology, it has become possible to make a radar simulator based on the personal computer. The advantage of the personal Computer aidd radar simulator lies in its cost effectiveness, when comparing with that using the real radar. Although there have been studies carried out to develop radar simulator using PC and the products of thi kind is in the commercial market already, they are all using the mockup of the real radar, and therefore, the price of the simulator is still rather expensive. In this respect, this thesis aims to develop a ARPA radar simulator which is running on the sole PC, so that the students of the maritime educational institution may get ARPA radar training easily and cheaply. The simulator developed in this thesis using Visual Basic is found to run successfully on the 486PC, and it is expected that this new simulator system designed first time in Korea would be used as an easily accessible ARPA radar training equipment.

• Journal of Navigation and Port Research
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• v.39 no.2
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• pp.83-88
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• 2015

Korea has a systemic problem with lack of engine maintenance, especially among the Commercial Fishing Vessel fleet. This results in a inordinate percent of SAR call-outs for vessels with engine failure. These SAR call-outs lead to a free tow to shore by KCG or by one of its volunteer associates. Although these tows are not a terrible economic burden on KCG, it is a burden in terms of time and resources mis-allocated. This paper proposes a Commercial Fishing Vessel Examination (CFVE) program modeled after the program run by USCG. It is expected that adopting the CFVE program, KCG may be able to create a culture of safety among fishermen; thus, replicating the USCG's success rates.

• Journal of the Korea Safety Management & Science
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• v.8 no.5
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• pp.167-180
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• 2006

This study expands limitation of OASIS(Optimal Allocation of Spares for Initial Supports) program, which calculates CSP(Concurrent Spare Part), not only availability but also cost, and developed the program enabling run in WINDOW OS. By considering multi-step repair and logistics support system, repairing capability at the time of deployment, and procurement period, this model is the first local model reflecting circumstances of the armed forces of the Republic of Korea. Furthermore, the programmed model was selected as the military standard software and has being essentially used for CSP calculation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.1
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• pp.93-99
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• 2011

A PRT vehicle's control method is presented in this paper. In the asynchronous vehicle control system, vehicles follow their leading vehicles. Leading vehicles are defined differently among the different types of track. The main topic of this paper is to present a method to define the leading vehicle among different types of track and the calculation algorithm of the safety length the following vehicle must maintain. Simulation program is developed using the algorithm and the results of the test run are presented. An asynchronous PRT vehicle control algorithm was presented by Szillat in the paper "A low level PRT Microsimulation, Dissertation, University of Bristol, 2001". But it is different from the algorithm in this paper. In the algorithm proposed by Markus, vehicles in the merging track are controlled synchronously, and its safety distance between the leading and the following car is evaluated after the establishment of the complicated future time-location table instead of simple equations proposed in this paper.

• Journal of the Korea Safety Management & Science
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• v.12 no.2
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• pp.139-146
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• 2010

The advent of Internet has greatly increased the ability of companies to conduct their business faster, more accurately, over a wider range of time and space, at reduced cost and with the ability to customize and personalize customer offerings. However it may be difficult for companies to sustain a long-run survival in competition environment of e-business. The purpose in this study is to analyze the relationship among site loyalty characteristics, customer's repurchasing intention and switching intention of internet shopping mall. The results showed that reputation variables of internet shopping mall only affected significantly e-loyalty. And the relationship among e-brand loyalty, customer's repurchasing intention and switching intention was significantly supported.

• Journal of the Korean Society of Safety
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• v.11 no.2
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• pp.33-41
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• 1996

Experiments were performed to study solidification of phase change material on a finned vertical tube when either conduction In the solid or natural convection in a liquid controls the heat transfer. The liquid was housed in a cylindrical containment vessel whose surface was maintained at a uniform, time-invariment temperature during a data run, and the solidification occurred at a finned and unfinned vertical tube positioned along the axis of the vassel. The phase change material(PCM) employed in this experiment is 99 percent pure n-Octacosan paraffin($C -{28}H_{58}/$). For conduction-controlled and convection-controlled solidification, the enhancement of the solidified mass rate due to finning is great when the solidified layer is thin and decreases as the layer grows thicker. It is studied that the latent energy($E_{\lambda}$) is the largest contributor to the total extracted energy($E_{\lambda} ＋ E_{sl}＋E_{s2}$) and the total extracted energy rate at a finned vertical tube is greater than that at a unfinned vertical tube.

• Journal of the Korea Safety Management & Science
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• v.12 no.4
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• pp.145-151
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• 2010

It seems that a primary concern of the project-based company, which provides a large scale product or service over long term period, is to run a successful project through systematic project process control and control costs. One of the typical project control methods is Earned Value Management System(EVMS) which analyses the precess through performance measurement. Even though the EVMS is a highly efficient tool in the managerial aspect, it cannot easily determine the Planned Value(PV), Actual Cost(AC), or Earned Value(EV) due to the indistinct criteria and extensive data. The accurate calculation of AC in particular, is the basic of project management, but most companies record direct personnel expenses or direct expenses only. Since they calculate indirect expenses based on the estimated ratio, it limits the systematic project management that reflects changes in profit and loss of a company. This study introduces a EVMS for project management and its actual case based on EVMS and ERP system which some additional modules are installed for performance measurement. It is expected that this new method enables a company to save time and effort, and also to improve transparency by specifying expense items in detail and to switch quarterly settlement to monthly by reducing the time of calculation.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.3
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• pp.232-238
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• 2004

The brake system of a high-speed train has a crucial role for the safety of human mass transportation. However, it is hard to acquire design parameters of the brake system in the design step of the new high-speed train. In this paper, we build a HILS (Hardware In-the- Loop Simulation) system for the brake system of the Korea High-Speed Train (KHST) that is supposed to run up to 350 km/h, and analyze the characteristics of the brake system of the KHST (composed of 7 cars) via real-time simulations. In the HILS system that is built using a DSP board of dSPACE, the dynamics of the 7 car bodies and several bogies and characteristics of springs and dampers of connection devices between cars are considered separately. Simulation results show that the designed brake system of the KHST is valid and satisfies design specifications.