• Proceedings of the KSR Conference
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• 2007.11a
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• pp.581-584
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• 2007

The subway concrete box structure can`t establish expansion joint because of animal power delivery of the subway rail. In this case, As increase of structure volume, it is subjected to cause temperature crack. The temperature crack due to the heat of hydration classified a nonstructural crack. but it has a bad effect on durability of concrete structures. especially, in case of a subway concrete box structure, when a water-proof facilities is beaked on an outer-wall, the water leakage occurs through a penetration crack generated from a wall of the concrete structure too. This paper, for the subway concrete box structure, examined a condition of temperature crack occurrence by a heat of hydration concerned external temperature from analysing by a three dimensional finite element method.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.19 no.37
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• pp.221-231
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• 1996

Applying JIT(Just-In-Time) production system to strength competitiveness power and renovate managent has problems. This study is proposed to solve one of the problems, that mother company has different production system with subcontractor, in order to connect production system of mother company with subcontractor. In the view of the Pull System, production system of mother company, it is possible that the more smoothed production planning is established by developing the algorithm the smoothed production planning preserving the LOTproduction system and comparing the existing research. Also, in the view of subcontractor taking Push System, the possibility of keeping delivery and improving productivity is proved using simulation technique by changing Job shop to GT Cell production system because demand is fluctuating.

• Journal of Multimedia Information System
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• v.7 no.1
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• pp.55-72
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• 2020

As the IT service environment grows, it is critical in terms of IT service quality to minimize the occurrence of failures due to changes in applications and to diagnose and recover in a short period of time how failure will affect the business. Thus, the Defense Acquisition Program Administration (DAPA) has been building and operating ITSMs to implement IT service management in a leading manner. Information Technology Service Management (ITSM) is divided into events, obstacles, changes, versions and setup management to ensure flexibility and stability in service delivery. It is also operated separately from service level, availability, capacity, financial and IT service continuity management to ensure service quality and cost efficiency. Based on ITSM military service history, this study looks at the impact of quality of service on value, satisfaction, and trust. The results of the analysis are highly valuable for future ITSM implementation and operation.

• Journal of Drive and Control
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• v.10 no.3
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• pp.7-13
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• 2013

Hydraulic vane pumps are widely used in various hydraulic systems because of its compactness and light weight. It is well known that the vanes and cam ring are separated by very thin liquid films which result in the EHL state. Contrary to the case of cylindrical roller bearings, the inlet and side boundary pressures are much higher than the atmospheric pressure. In this paper, a numerical solution of the EHL of finite line contacts between the cam ring and vane tip with profiled ends is presented. Using a finite difference method with non-uniform grids and the Newton-Raphson method, converged solutions are obtained for moderate load and material parameters. The EHL pressure distribution and film shape are considerably affected by pump delivery pressure and the side boundary condition applied. Both the maximum pressure and the minimum film thickness always occurred near the edge regions. The present results can be used in the design of optimum vane profile in hydraulic vane pump.

• Management Science and Financial Engineering
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• v.20 no.2
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• pp.7-12
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• 2014

Content Delivery Network (CDN) has evolved to overcome a network bottleneck and improve user perceived Quality of Service (QoS). A CDN replicates contents from the origin server to replica servers to reduce the overload of the origin server. CDN providers would try to achieve an acceptable performance at the least cost including the storage space or processing power. In this paper, we introduce a new optimization model for the CDN design problem considering the user perceived QoS and single path (non-bifurcated) routing constraints and analyze the computational complexity for some special cases.

• International Journal of Quality Innovation
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• v.2 no.1
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• pp.106-116
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• 2001

The purpose of business strategy is to achieve competitive advantages which includes higher efficiency, better quality, more innovation and faster customer response. In other words, The business strategy is to build unique capability of lower cost and/or differentiation. In production aspect, unique capability means better production power with better performance at 3M(Man, Machine, Material) of input and PQCDSM (Product, Quality, Cost, Delivery, Safety, Moral) from output. The Total Productive management (TPM), a series of improvement activities focused on reduction of equipment loss, is a tool to establish business competitive advantages. In this paper, several domestic companies who won the Japan TPM Award have been studied. It is found that there is a strong cause-effect relationship between TPM and competitive advantages because. 1. TPM can change employees mindset effectively. 2. TPM can upgrade employees capabilities. 3. TPM can lead to excellent productivity.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.616-620
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• 2006

IEEE 802.15.4 is designed for low-rate wireless personal area networks (LR_WPAN) and it attempts to provide a low data rate, low power, low cost wireless networking on the device-level communication. In this paper, I have established a realistic environment for the effect of collision in nonbeacon-enabled mode and beacon enabled mode. The data throughput and delivery ratio are investigated as the performance metrics.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2001.06a
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• pp.57-60
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• 2001

Most power retailers adopt systematic, integral supply chain system to minimize the logistics cost. However, small and medium sized retail shops that don't have a distribution channel, unavoidably spend a big amount of distribution cost. This study is to propose an efficient system to manage the information of trucks by using the portable GPS. This system includes the real-time mapping of truck location, the transmission of delivery information from the truck, and the algorithm concerning the selection of the most cost efficient truck.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.2
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• pp.1-7
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• 2003

This paper proposes a method to detect misfired cylinders by the exhaust pressure ascent rate. The misfire is generated by faults of electric system or faults of fuel delivery system. It is one of the abnormal combustions. Therefore, it increases the unburned hydrocarbon and the carbon monoxide and affects a bad influence to the 3-way catalyst. The misfire causes to decrease the power of the engine and increase the consumption of the fuel. Early detection and correction of the misfired cylinders can prevent these unusual phenomena. The misfired cylinders can be detected by the comparison of exhaust pressure ascent rate during each cycle. The exhaust pressure ascent rate is defined as pressure rise per time. Our experimental results showed that the proposed method is effective in the detection of the misfired cylinders on a gasoline engine regardless loads and revolutions of the engine.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.55
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• pp.43-50
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• 2000

Recently, the companies can't avoid the change toward the jobbing production from mass production because manufacturing types are changed from manufacturing-oriented to customer-oriented for the security of competitive power among the related companies. The jobbing production system usually has such problems as low productivity, high unit cost, much stocks, long manufacturing time and one-sided decision of delivery date compared with the mass production. In order to settle these problems in the jobbing production system, we introduced the JIT production system including 3 regulations & 6S activities and Kanban system etc. The effective operation of JIT production system makes the processes efficiently and reduces the unneeded stocks and maximizes the revenue of company.