• Journal of the Korean Society for Library and Information Science
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• v.57 no.3
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• pp.97-117
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• 2023

The purpose of this study is to suggest a mid- to long-term expansion plan to resolve the blind spot and alleviate the imbalance of public library services in Daegu City. The research methods for this purpose included literature review, related laws and statistical data analysis, case study, and opinion survey. As a result, the first service area was set as a total of 14 areas based on administrative districts(Jung-gu, Seo-gu, Nam-gu, and Dalseong-gun each have one, Dong-gu and Buk-gu each have two, and Suseong-gu and Dalseo-gu have three each). Second, the expansion scenario for public libraries in Daegu City was proposed to add 26 libraries by the final target year (2032) based on the trend of national library growth over the past 13 years (2008-2020) and the forecast for the next 10 years (2023-2032). Third, the construction scenarios for each basic local government, excluding the Daegu representative library, are as follows: One library each in Jung-gu, Seo-gu, and Nam-gu; two libraries in Suseong-gu; three libraries in Dalseong-gun; four libraries in Dong-gu; and seven libraries each in Buk-gu and Dalseo-gu. In terms of floor area, it is proposed to add a total of 17 branch libraries with a minimum legal standard of 330-2,499㎡, four central libraries with 2,500-4,999㎡ each, and four central libraries with 5,000-9,999㎡ each. On the premise of these conditions, Daegu City and public libraries should focus on creating an inclusive and open community space, creating a digital platform, strengthening the library operation and cooperation system centered on Daegu representative library, developing collections and specializing services for local hub libraries, enhancing various knowledge information and program services, managing key library indicators and improving social contribution.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.4D
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• pp.547-553
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• 2011

This study has redefined the concepts of mobility indexes and potential demand, standards to evaluate areas with the worst public transportation system and applied the relevant indexes to select the areas with the worst public transportation mobility and present a method to set direct public transportation lines between these regions. The mobility indexes and indexes to evaluate potential demand were applied to select the regions with the worst public transportation systems in four metropolitan cities and case studies were carried out on direct lines provided between these regions. The analysis results showed that in public transportation mobility blind spots, public transportation takes much longer than driving an automobile or public transportation services are not provided. In addition, the analysis showed that a direct lines system to solve such worst off regions should be built to have public transportation take as much time as driving an automobile by establishing lines for automobiles only, minimize time lost from hopping up and down a bus and maximize connections.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.1
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• pp.355-365
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• 1991

New definition for the interaction of flames is introduced and interacting turbulent diffusion flames issuing from two rectangular nozzles are investigated on the basis of the definition. Theoretical study through numerical model is carried out and experiment for validation is conducted. The characteristics of interaction due to the variation of major parameters such as nozzle spacing, Reynolds number and nozzle aspect ratio are studied. Results show that strong interaction occurs for small nozzle spacing, small Reynolds number and large aspect ratio. In order of their magnitude, the intensity of interactions on the individual transport mechanism is momentum, heat and mass. It is also found that interaction makes flames longer, tilted and finally merged. Increase of velocities and temperature, decrease of oxygen concentration and depression of turbulence are occurred in the region between flames.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.5
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• pp.475-479
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• 2003

Traditional ultrasonic evaluation to detect micro/small surface cracks is the pulse-echo technique using the normal immersion transducer with high frequency, or the angle beam transducer with surface wave. It is difficult to make the automatic ultrasonic system that is to detect micro and small surface crack and position on the large structure like steel and ceramic rolls, because of the huge data of inspection and the ambiguous position data of transducer. The aim of this study using the high precision scanning acoustic microscope with 10MHz large aperture transducer was to display the real time A, B, C-scan for the automatic ultrasonic system in order to detect the existence and position of surface crack. The ultrasonic method with large aperture transducer was improved the scanning time and speed over 10times faster than traditional methods.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.10
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• pp.1012-1015
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• 2011

The decision-directed blind equalization algorithm is often used due to its simplicity and good convergence property when the eye pattern is open. However, in a channel where the eye pattern is closed, the decision-directed algorithm is not guaranteed to converge. Hence, a modified Bussgang-type algorithm using a hyperbolic tangent function for zero-memory nonlinear(ZNL) function has been proposed and applied to avoid this problem by Filho et al. But application of this algorithm includes the calculation of hyperbolic tangent function and its derivative or a look-up table which may need a large amount of memory due to channel variations. To reduce the computational and/or hardware complexity of Filho's algorithm, in this paper, an improved method for the decision-directed algorithm is proposed. In the proposed scheme, the ZNL function and its derivative are respectively set to be the original signum function and a narrow rectangular pulse which is an approximation of Dirac delta function. It is shown that the proposed scheme, when it is combined with decision-directed algorithm, reduces the computational complexity drastically while it retains the convergence and steady-state performance of the Filho's algorithm.

• Journal of Energy Engineering
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• v.17 no.1
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• pp.1-7
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• 2008

The present study has been conducted to understand the heat and mass transfer characteristics of humid airflow in frosting conditions. A flat plate of aluminum was used for the simulation of flat surface part of the fin of the heat exchanger. The aluminum surface temperatures were measured and analyzed to clarify the heat and mass transfer characteristics under frosting conditions. Also, the pressure drops were measured to clarify the air-blocking effect of frost in the mini channel of the air-side hoot exchangers. A data reduction method was developed far the analysis of local characteristics of humid air under frosting conditions.

• The Journal of the Acoustical Society of Korea
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• v.30 no.6
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• pp.303-307
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• 2011

This paper describes an audio watermarking using Quantization Index Modulation (QIM) on significant peaks in frequency domain. The audio signal is broken up into L samples length frames with non-overlapping and rectangular window. The zero-crossing rate of each frame is calculated for decision whether it is proper to be watermarked or not. If the frame is legitimate, frequency magnitude response is computed by discrete Fourier transform. For the QIM, we set the quantization step size based on maximum value of frequency magnitude response and select n significant peaks with w samples around them in frequency domain, totally $n{\times}(w+1)$ samples. Finally, watermark embedding is performed. Decoder extract watermarks based on Euclidean distance, that is a blind detection. The proposed method is robust against many attacks of watermark benchmark.

• Journal of the Korea Convergence Society
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• v.6 no.6
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• pp.1-8
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• 2015

In this paper, we proposed image enhancement method using sharpening filter for improving the accuracy of object detection using the existing Grabcut algorithm. GrabCut algorithm is the excellent performance extracting an object within a rectangular window range, but it has the drawback of the inferior performance in image with no clear distinction between background and objects. So, in this paper, reinforcing the brightness and clarity through histogram equalization, and tightening the border of the object using the sharpening filter look better than that extracted result of existing GrabCut algorithm in a similar image of the object and the background. Based on improved Grabcut algorithm, it is possible to obtain an improved result in the image processing convergence technique of character recognition, real-time object tracking and so on.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.2
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• pp.158-173
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• 1985

An experimental investigation has been made to study the interaction between and incident oblique shock wave and an unstabilized turbulent boundary layer on a solid surface downstream of a porous surface with air injection through the porous surface. The boundary layer upstream of the interaction is unstabilized by the injection and provokes a shock wave which eventually interacts with the unstabilized boundary layer after reflecting from the upper wall of the test section. Three cases having diferent upstream Mach numbers and different shock strengthes are studied. According to the level of the unstabilization, two cases are of attached boundary layers and the other one is of a separated boundary layer. The result shows that the reflected wavey system is composed of the compression wave, expansion wave fan, and recompression wave like the ordinary interaction while the separated boundary layer strengthens the reflected expansion waves. The interactions of the attached boundary layers show a similar tendency of the upstream wall pressure distribution as that of the ordinary interacton but the pressure rise rather decays in the downstream region. In case of the separated boundary layer, the wall pressure continues to rise in the downstream as opposed ot the former cases. This indicates that the interaction region spreads out widely adn the viscous effect of the separated boundary layer smoothens the abrupt pressure increase due to the shock inpingement.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.7
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• pp.777-787
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• 2012

The transient analysis for the output voltage of a piezoresistive microaccelerometer takes a relatively high computation time because at least two iterations are required to calculate the piezoresistive-structural coupled response at each time step. In this study, the high computational cost for calculating the transient output voltage is considerably reduced by an approach integrating the mode superposition method and the least square method. In the approach, data on static displacement and output voltage calculated by piezoresistive-structural coupled simulation for three acceleration inputs are used to develop a quadratic regression model, relating the output voltage to the displacement at a certain observation point. The transient output voltage is then approximated by a regression model using the displacement response cheaply calculated by the mode superposition method. A high-impact microaccelerometer subject to several types of acceleration inputs such as 100,000 G shock, sine, step, and square pulses are adopted as a numerical example to represent the efficiency and accuracy of the suggested approach.