• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.3
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• pp.171-177
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• 2016

Noise problem that occurs in living environment is a big trouble in the economic, social and environmental aspects. In this paper, the filtered-X LMS algorithms, the adjoint LMS algorithms, and the robust adjoint LMS algorithms will be introduced for applications in active noise control(ANC). The filtered-X LMS algorithms is currently the most popular method for adapting a filter when the filter exits a transfer function in the error path. The adjoint LMS algorithms, that prefilter the error signals instead of divided reference signals in frequency band, is also used for adaptive filter algorithms to reduce the computational burden of multi-channel ANC systems such as the 3D space. To improve performance of the adjoint LMS ANC system, an off-line measured transfer function is connected parallel to the LMS filter. This parallel-fixed filter acts as a noise controller only when the LMS filter is abnormal condition. The superior performance of the proposed system was compared through simulation with the adjoint LMS ANC system when the adaptive filter is in normal and abnormal condition.

• Journal of Mechanical Science and Technology
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• v.20 no.4
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• pp.569-579
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• 2006

In the present study, the unsteady Couette flow with heat transfer of a dusty viscous incompressible electrically conducting fluid under the influence of an exponential decaying pressure gradient is studied without neglecting the Hall effect. The parallel plates are assumed to be porous and subjected to a uniform suction from above and injection from below while the fluid is acted upon by an external uniform magnetic field is applied perpendicular to the plates. The governing equations are solved numerically using finite differences to yield the velocity and temperature distributions for both the fluid and dust particles.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.390-395
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• 2001

Cooling characteristics using convection and conduction heat transfer in a parallel channel with extruding heat sources are studied numerically. A two-dimensional model has been developed for numerical prediction of transient, compressible, viscous, laminar flow, and conjugate heat transfer between parallel plates with uniform block heat sources. The finite volume method is used to solve this problem. The considered assembly consists of two channels formed by two covers and one PCB which has three uniform heat source blocks. Five different cooling methods are considered to find efficient cooling method in a given geometry and heat source. The velocity and temperature fields, local temperature distribution along surface of blocks, and the maximum temperature in each block are obtained.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.3
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• pp.294-302
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• 1998

The charateristics of the convective mass transfer in horizontal rectangular enclosure with horizontal concentration gradients are analyzed. The effect of Grashof number(Gr) and aspect ratio(L/H) is investigated numerically using the control-volume method. Numerical results are obtained for Grashof numbers between $10^4$ and $10^6$ aspect ratios from 1 to 100 and results are compared with existing andlytical results. It is found that there exists a well defined aspect ratio for which the mean Sherwood number is maximum and the core flow changes from parallel to non-parallel at $Gr^2{Sc^2}(A^{-3}}{\geq}{10^5}$ and in the Ralongrightarrow0 regime the numerical results agreed very well with correlation derived from analytical results.

• Journal of the Korean Operations Research and Management Science Society
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• v.25 no.2
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• pp.33-46
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• 2000

The problem of scheduling n independent jobs on serial stages with identical parallel machines at each stage is considered. Each job lot is allocated evenly to all machines at each stage for processing and moved in transfer batches between states., This scheduling strategy is called an identical production pattern. The objective is to find a permutation schedule that minimizes makespan. A branch and bound algorithm is suggested to find an optimal permutation schedule for a transformed problem A number examples is presented to illustrate the branch and bound algorithm, Computational results for 640 problems generated randomly show that within a resonable time the suggested algorithm can be used for transfer batch scheduling in a flexible flowshop.

• Solar Energy
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• v.6 no.2
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• pp.62-69
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• 1986

An analysis is made of the fully developed laminar flow and heat transfer in a parallel flat plate with heated rectangular block arrays to investigated the influence of bouyancy force. The shrouds is considered as adiabatic, while the heated block surface transmit a uniform rate of heat flux per unit axial length. The governing equations for velocity and temperature are solved by SIMPLE(Semi-Implicit Method Pressure Linked Equation) algorithm. Detailed velocity and temperature fields and overall heat transfer on wide range of Rayleigh number and various aspect ratios of heated rectangular blocks are computed. The result show that bouyancy leads to a significient enhancement in heat transfer along with a smaller increase in pressure drop, with the great enhancement found when the aspect ratio is 3.0.

• Journal of Mechanical Science and Technology
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• v.17 no.8
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• pp.1226-1233
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• 2003

Experimental heat transfer data for single-phase water flow in the annuli with corrugated inner tubes are presented. In the annuli with parallel flow, ten different annular arrangements are considered. For water flow rate in 1,700${\gamma}$$\^$*/). As P/e becomes closer to 8 in the range below the radius ratio (${\gamma}$$\^$*/) of 0.5, Nusselt numbers increase. However, Nusselt numbers decrease in the range above the radius ratio (${\gamma}$$\^$*/) of 0.5 because flow reattachment position becomes farther in the narrower clearance.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.6
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• pp.477-483
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• 2020

This study proposes a DQ synchronous reference frame model of a series-parallel tuned inductive power transfer (SP-IPT) system. The wireless power transmission system experiences control difficulty because the transmitter-side controller cannot directly measure the receiver-side load voltages and currents. Therefore, a control-oriented circuit model that shows the dynamics of the IPT system is required to achieve a well-behaved controller. In this study, an equivalent circuit model of the SP-IPT system in a synchronously rotating reference frame is proposed using the single-phase DQ transformation technique. The proposed circuit model is helpful in modeling the dynamics of the voltages and currents of the transmitter- and receiver-side resonant tanks and loads. The proposed circuit model is evaluated using frequency- and time-domain simulation results.

• Industrial Engineering and Management Systems
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• v.4 no.2
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• pp.117-122
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• 2005

An assembly system (AS), a valuable tool for mass production, is generally composed of a number of workstations and a transport system. While the workstations perform some preplanned operations, the transport system moves the assemblies by special designed pallets from one station to another. One common problem associated with automatic assembly systems is that some assembly operations may have relatively long cycle times. As a consequence, the productivity, as determined by the operations with the longest cycle time, can be reduced significantly. Therefore, special forms of parallel workstations were developed to improve the performance of an assembly system. In this paper, three most commonly used parallel stations: on-line, off-line and tunnel-gated stations in a free transfer assembly system are studied via discrete event simulation. Our findings revealed that the off-line parallel system has the best performance because the two independent parallel stations can lower the buffer requirement; reduce the sensitivity to variability of processing time and balance of a line. On-line parallel systems were found to have a relatively poor performance, because the operations of two parallel stations block each other, and higher buffer capacity is required to achieve similar capacity. The tunnel-gated system was more efficient than the on-line system since the first parallel station can operate independently. More importantly, we have quantified the productivity of the three different strategies mentioned. Engineers can choose the optimal strategies for installing parallel stations under their working environment.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.8
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• pp.1043-1050
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• 2013

Parallel robots used in industry require high stiffness or high speed because of their structural characteristics. Nowadays, the importance of rapid transportation has increased in the distribution industry. In this light, an industrial parallel robot has been developed for high-speed transfer. The developed parallel robot can handle a maximum payload of 3 kg. For a payload of 0.1 kg, the trajectory cycle time is 0.3 s (come and go), and the maximum velocity is 4.5 m/s (pick amp, place work, adept cycle). In this motion, its maximum acceleration is very high and reaches approximately 13g. In this paper, the design, analysis, and performance test results of the developed parallel robot system are introduced.