• Journal of the Korean Operations Research and Management Science Society
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• v.5 no.1
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• pp.39-51
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• 1980

This paper deals with the problem of determining the capacity expansion timing and sizes of conduits and feeder cables for a given cable network configuration of a single exchange ares, which minimizes the present worth of total costs. The planning horizon is infinite and the demand of line pairs at each cabinet is assumed to be determininstically growing. As a solution method, the heuristic branch-and-bound algorithm of Freidenfelds and Mclaughlin is elaborated by adding details and some minor modifications, which generates a good near-optimal solution with far less computation than would otherwise be possible. We also develop a computer program, which is shown to be effective and efficient through the test run of an illustrative example.

• 한국연소학회:학술대회논문집
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• 2005.10a
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• pp.132-137
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• 2005

The burning characteristics of interacting spherical droplet in a turbulent flow are numerically investigated. The transient combustion of 3-dimensionally arranged droplets, both the fixed streamwise droplet distances of 3 radii and 10 radii and different turbulence intensities, is studied. The results obtained from the present numerical analysis show that droplet vaporization rate for heptane droplet is insensitive to turbulence intensity, and that the transient flame configuration and retardation of droplet surface temperature augmentation with streamwise droplet spacing substantially influence vaporization process of interacting droplets. Single flame mode in which individual flames are merged into single flame, with decreasing streamwise droplet spacing, becomes faster. Therefore, vaporization rate of the second droplet with decreasing streamwise droplet spacing decreases remarkably with flame movement.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.630-632
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• 2018

The compensation characteristics of the distorted WDM channels compensated for by dispersion management (DM) and optical phase conjugation in the long-haul (50 fiber spans ${\times}$ 80 km) transmission link with the randomly distributed single mode fiber (SMF) length and residual dispersion per spans (RDPS) for implementing of the flexible link configuration are investigated.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.8
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• pp.621-626
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• 2012

A new baffle configuration, an annular baffles, are considered in the present study as an alternative to reduce the excessive pressure drop associated with the conventional segmental ones in typical operating conditions. The heat transfer and pressure drops are numerically simulated for a single tube shell-and-tube model and compared against the conventional-baffle cases. Baffle blockage ratio and number of baffles are considered as the major variables for the present study specifying a fixed baffle spacing. It is found that the heat transfer increases 1.4~2.2 times without significant pressure loss compared to the bare tube cases and the goodness factor increases 1.35 times compared to the conventional-baffle model.

• Journal of the Optical Society of Korea
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• v.20 no.2
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• pp.245-250
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• 2016

In this paper, we demonstrate a self-imaging technique that can visualize longitudinal interference patterns behind periodically-structured objects, which is often referred to as Talbot carpet. Talbot carpet is of great interest due to ever-decreasing scale of interference features. We demonstrate experimentally that Talbot carpets can be imaged in a single exposure configuration revealing a broad spectrum of multi-scale features. We have performed rigorous diffraction simulations for showing that Talbot carpet print can produce ever-decreasing structures down to limits set by mask feature sizes. This demonstrates that large-scale pattern masks may be used for direct printing of features with substantially smaller scales. This approach is also useful for characterization of image sensors and recording media.

• Journal of the Optical Society of Korea
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• v.20 no.2
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• pp.223-227
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• 2016

The impact of optical receiver configuration on in-band crosstalk-induced penalty has been investigated in both theoretical and experimental analyses, for differential phase-shift keying (DPSK) and differential quadrature phase-shift keying (DQPSK) signals. Previously it has been shown that DPSK signals are ~6 dB more tolerant to in-band crosstalk than on-off keying (OOK) signals. However, we find that the tolerance difference between the two signals is reduced to ~3 dB when the decision threshold of the receiver is optimized to minimize the bit-error rate for each signal. Then we derive simple equations for the in-band crosstalk-induced penalty in DPSK and DQPSK signals with two different optical receiver configurations: balanced and single-ended direct-detection receivers. We confirm that the penalties obtained from our simple equations agree well with the measured results.

• Korean Journal of Crystallography
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• v.16 no.1
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• pp.1-5
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• 2005

The structure of the title compound has been determined by single-crystal X-ray diffraction work. The crystals are orthorhombic, space group $Pna2_1$ with a=11.095(3), b=21.834(7), c=12.574(4) $\AA$, and R1=0.0667. The average carbon bond length in aromaticity In the molecule is 1.386(1) $\AA$ and the average single bond length linking the central benEene ring and peripheral phenyl rings is 1.491(3) $\AA$. The average dihedral angle between the central benzene ring and each of six peripheral phenyl rings is $67.1(1)^{\circ}$ and the average dihedral angle between neighboring two phenyl rings is $55.0(1)^{\circ}$. Thus the molecule adopts a quasi-propeller configuration with approximate six-fold rotation symmetry.

• Journal of information and communication convergence engineering
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• v.5 no.4
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• pp.362-368
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• 2007

A single-phase uninterruptible power supply system equipped with a superconducting magnet energy storage unit is proposed to achieve a simple circuit configuration and higher system reliability. It reduces a number of switching devices by applying a common-arm scheme. Removing some switches or substituting passive elements for active switches can increase the sophistication and reduces degree of freedom in control strategy. However, high-performance DSP controller can execute the complicated control task with no additional cost. Operational principles to normal, stored-energy, and bypass mode are discussed in detail. The validity of the proposed system is verified by experimental results.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.743-746
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• 2006

We have demonstrated a transflective liquid crystal display (LCD) with a single cell gap in a patterned vertically aligned mode. In our configuration, the different electrode structure in a transmissive and a reflective part was suggested to compensate an optical path difference of each region. As the result, the similar electro-optic characteristic of each region was obtained which results in an enhanced performance of the device. Moreover, suggested technique can be highly effective to realize the practical transflective LCD due to the simple fabrication process.

• Journal of the Korean housing association
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• v.19 no.3
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• pp.71-81
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• 2008

A traditional Korean housing is a typical type which is contained life style, spatial organization and scape element of people who lived in Korea. In the hanok, people want to be live not only in human environment and traditional culture, but also modem urban housing as a high density. This article deals as follows: First, Hanok as urban housing would be composed in a housing lot, linear type layout, devide building, and cluster type. Second, Housing unit and configuration of Multi family housing can be used single story, second story, second story + single story, multi story and Hanok roofing. Thirds, structure of the building are traditional wooden, combined one of steel and wood or concrete and wood, and the building system in exterior and interior can be seperated into another system. Forth, Image of multi story Hanok A last, consistency of Hanok is not a repeat of an origin but application and creative aptitude of the origin, and multi family housing application of Hanok can be a trial creative.