• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.2
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• pp.174-185
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• 2002

The automotive industry faces many competitive challenges including weight and cost reduction to meet need for higher fuel economy. Tailored blanks offer the opportunity to decrease door weight, reduce manufacturing costs, and improve door stiffness. Optimization technology is applied to the inner panel of a door which is made by tailored blanks. The design of tailored blanks door starts from an existing door. At first, the hinge reinforcement and inner reinforcement are removed to use tailored blanks technology. The number of parts and the welding lines are determined from intuitions and the structural analysis results of the existing door. Size optimization is carried out to find thickness while the stiffness constraints are satisfied. The door hinge system is optimized using design of experiment approach. A commercial optimization software MSC/NASTRAN is utilized for the structural analysis and the optimization processes.

• Journal of Multimedia Information System
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• v.4 no.4
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• pp.239-242
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• 2017

This paper proposes a low-cost method for counting people based on blob detection and blob tracking. Here background subtraction is used to detected blob and then the blob is classified with its width and height to specify that the blob is a person. In this system we first define the area of entry and exit point in the video frame. The counting of people starts when midpoint of the people blob crosses the defined point. Finally, total number of people entry and exit from the place is displayed. Experiment result of this proposed system has high accuracy in real-time performance.

• Journal of Korean Institute of Industrial Engineers
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• v.26 no.2
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• pp.81-87
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• 2000

As for M/G/1 queueing system, we use various control policies, with which we can optimize the system. Up to now the most widely adopted policies are N-Policy, T-Policy, D-Policy, and so on. The existing researches are largely concerned to find an optimal operation condition or to optimize the system under single policy in M/G/1 system. There are, however, few literatures dealing with multiple control policies at once to enhance the flexibility of the model. In this study, we consider M/G/1 system adopting N-Policy and T-Policy simultaneously. If one of two conditions is satisfied, then, the server starts the service. We call this Min(N,T)-Policy. We find the probability distribution of the number of customers and mean waiting time in steady state and derive a cost function. Next, we seek the $N^*$, optimal threshold under various N values. Finally, we reveal the characteristics of cost function.

• Bulletin of the Society of Naval Architects of Korea
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• v.17 no.1
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• pp.31-37
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• 1980

Herein the flow past a submerged circular cylinder with a free surface is mapped onto a reference plane, in which the free surface is transformed to a straight line and the cylinder to a certain shape. A global mapping function between two planes is sought in a manner that linear free-surface elevation is generated in the physical plane. Hereby the Froude mumber $F_h$, based on the submergence depth h', is assumed to be of order 0(1) and the ratio a'/h'(a'=cylinder radius) of order o(1). Wave thus obtained are slightly different in magnitude and phase from usual linear solution. The resulting free wave starts advanced ahead compared to the classical result and its amount depends on Froude number. Based on the present concept wave forces are calculated. In this type of approach the body boundary condition gives more influence on wave resistance than that by the free surface in the speed range $F_h>1$.

• Journal of ILASS-Korea
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• v.14 no.4
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• pp.184-189
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• 2009

Recently, ultrafine particles emitted from internal combustion engine is main concern because of its well known adverse health effects. So Europe decided to start the regulation about diesel engine particle number emissions. The nanoparticles smaller than 50nm in diameter have the ability to penetrate deep into interstitial tissue of luge, where they may cause severe respiratory inflammation and acute pulmonary toxicity. Recent studies have showed that spark ignition engines emit particles number concentration comparable to those from diesel engines with DPF under high load and rich mixture conditions, including cold starts and acceleration. So this study investigated emission characteristics of ultrafine particles according to fuel injection type in gasoline vehicles and LPG vehicles. The test vehicles were tested on CVS-75 and NEDC vehicle test mode using the chassis dynamometer, CPC system applied as a particle measuring instrument at the end of dilution tunnel. As a result, the correlation between fuel injection type and particulate emission was determined. GDI vehicle emitted 10 times higher particles than PFI vehicles, and compared to Mixer and LPGI type LPG vehicle, LPLI vehicle emitted particles high.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.7
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• pp.72-84
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• 2001

This paper proposes a design methodology for customer, assembly and disassembly considering recycling. The disign process starts with the identification of customer needs, which are in turn converted into functional requirements. The concepts of Design for Customer(DFC), Design for Assembly(DFA), Design for Variety(DFV) and Design for Disassembly(DFD) are considered in the product design phases in order to decreas production variety and mass customization. And, a new module generation approach is developed for rearranging and clustering parts and subassemblies for disassembly and recycling. Based on the result of the module generation, a new configuration methodology is suggested to minimize the disassembly time or number of disassembly operations for recycling.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.04b
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• pp.187-194
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• 2000

Weight reduction for an automobile body is being sought for the fuel efficiency and the energy conservation. One way of the efforts is adopting Ultra Light Steel Auto Body (ULSAB) concept. The ULSAB concept can be used for the light weight of an automobile door with the tailor welded blank (TWB). A design process is defined for the TWB. The inner panel of door is designed by the TWB and optimization. The design starts from an existing component. At first, the hinge and inner reinforcements are removed. In the conceptual design stage, topology optimization is conducted to find the distribution of variable thicknesses. The number of parts and the welding lines are determined from the topology design. In the detailed design process, size optimization is carried out to find thickness while stiffness constraints are satisfied. The final parting lines are determined by shape optimization.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.2 s.95
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• pp.164-175
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• 1999

If the camera plane is nearly parallel to the calibration board on which objects are defined, most of existing calibration approaches such as Tsai's radial-alignment-constraint method cannot be applied. Recently, for such an ill-conditioned case, Zhuang & Wu suggested the linear two-stage calibration algorithm assuming that the exact values of focal length and scale factor are known a priori. In this paper, we developed an iterative two-stage algorithm starts with initial guess fo the two parameters to determine the value of the others using Zhuang & Wu's method. In the second stage, the two parameters are locally optimized. This process is repeated until any improvement cannot be expected any more. The performance comparison between Zhuang & Wu's method and our algorithm shows the superiority of ours. Also included are the computational results for the effects of the distribution and the number of calibration points on the calibration performance.

• Journal of the Korean Operations Research and Management Science Society
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• v.27 no.2
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• pp.111-121
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• 2002

In this paper, we analyze an M$^{x}$ /G/1 with three types of vacation periods including setup time. Three types of vacations are : N-policy, single vacation, and multiple vacation. We consider compound poisson arrival process and general service time, where the server starts his service when a setup is completed. We find the PGF of the number of customers in system and LST of waiting time, with welch we obtain their means. A decomposition property for the system sloe and waiting time is described also.

• Journal of the Korean Society for Library and Information Science
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• v.36 no.3
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• pp.181-200
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• 2002

This paper starts by exploring the definition and scope of digital culture contents under digital environments. It then analyzes the classification system of search engines about digital culture contents in terms of subject catagories and the number of web documents. Finally, this study suggests the recommendations for effective retreival and management of digital culture contents.