• Journal of the Society of Naval Architects of Korea
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• v.46 no.2
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• pp.105-113
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• 2009

A theoretical study on the pressure fluctuation induced by a propeller was carried out in this study. The main objective of this study is to analyze the source mechanism of the pressure fluctuation induced by propeller sheet cavitation. To analyze the pressure fluctuation induced by propeller sheet cavitation, modern acoustic theory was applied. Governing equation of pressure fluctuation induced by sheet cavitation was derived using Ffowcs Williams proposed time domain acoustic approaches. Several factors affecting pressure fluctuation were analyzed based on the derived governing equation. Pressure fluctuation result was represented by combined results of the far field term and near field term. Finally, the physical mechanism of pressure fluctuation at the blade rate frequency was analyzed using numerically generated cavitation volume variation.

• Journal of Digital Convergence
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• v.11 no.3
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• pp.293-298
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• 2013

We consider about software quality nowadays. The company considers about software quality more and more compare to software development. We analyze the software testing data in this paper. We find the software effect according to the number of testing, the number of testing date, the number of fault according to characteristics. Also, we analyze the result by regression. Also, we propose the testing effect by sex.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.217-221
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• 2000

In this paper, we analyze the effect of phase noise from PLL frequency synthesizer on 64QAM when detecting the corrupted signals. To predict the phase noise of oscillator very accurately, we considered that oscillator has the linearly time-varying nature when the input impulsive torrent to oscillator is small. The performance which detects the corrupted signal by oscillator phase noise is compared with only affected by AWCN and then analyze how much it degrade system performance for 64QAM.

• Korea Trade Review
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• v.47 no.6
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• pp.211-228
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• 2022

With the advent of a recent knowledge-based society, interest in patents is steadily increasing. The patent is an important indicator that can capture the level of R&D investment and technology development. In an era of deepening new protectionism and the pandemic of COVID-19, patents play an important role in sustainable economic development and establishing a strong domestic industrial ecosystem. In this paper, we analyze the impact of patent applications on the corporate performance of the Korean manufacturing industry over the past 21 years from 1999 to 2019. We divide patents into overseas patents and domestic patents and analyze the respective effects on the entire manufacturing industry, ICT industries, and non-ICT industries. Major findings are summarized as follows. First, patents have a positive effect on both exports and sales of Korean manufacturing companies. Second, overseas patents have a greater impact on corporate performance than domestic patents. Third, Patents have a more positive effect on ICT industries than on non-ICT industries.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.646-649
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• 2002

It can be effect on diagnosis of hydraulic machining system to analyze working conditions with shape characteristics of wear debris in a lubricated machine. But, in order to predict and estimate working conditions, it is need to analyze the shape characteristics of wear debris and to identify. Therefor, if shape characteristics of wear debris is identified by computer image analysis and the neural network, it is possible to find the cause and effect of moving condition. In this study, wear debris in the lubricant oil are extracted by membrane filter, and the quantitative value of shape characteristics of wear debris we calculated by the digital image processing. This morphological informations are studied and identified by the artificial neural network. The purpose of this study is In apply morphological characteristics of wear debris to prediction and estimation of working condition in hydraulic driving systems.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.4
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• pp.197-203
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• 2003

Accurate stress intensity factor analyses and crack growth rate of surface -cracked components in inhomogeneous materials are needed fur reliable prediction of their fatigue life and fracture strengths. This paper describes an automated stress intensity factor analysis of three-dimensional (3D) cracks in inhomogeneous materials. 3D finite element method (FEM) was used to obtain the stress intensity factor fur subsurface cracks and surface cracks existing in inhomogeneous materials. To examine accuracy and efficiency of the present system, the stress intensity factor for a semi-elliptical surface crack in a plate subjected to uniform tension is calculated, and compared with Raju-Newman's solutions. Then the system is applied to analyze cladding effect of subsurface cracks in inhomogeneous materials. The results were compared with those surface cracks in homogeneous materials. It is clearly demonstrated from these analyses that the stress intensity factors for subsurface cracks are less than those of surface cracks. Also, this system is applied to analyze cladding effect of surface cracks in inhomogeneous materials.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.984-985
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• 2014

This research investigates to analyze the effect of laser of thermally assisted magnetic recording system on diamond like carbon (DLC) layer of slider. We investigated a damaged DLC layer of slider with laser spot-induced damage and analyze the effect of the damaged DLC layer in slider dynamics. The damaged DLC layer resulted in change of flying height and air bearing stiffness pressure.

• Journal of Digital Convergence
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• v.18 no.9
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• pp.145-157
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• 2020

The purpose of this study is first to analyze the effects of university students' autonomous motivations to start a business on their attitude toward entrepreneurship, subjective norms, and perceived behavioral control, second to analyze the effect of university students' attitude toward entrepreneurship, subjective norms, and perceived behavioral control on entrepreneurship intentions, and third to analyze the moderating effect of entrepreneurship education for university students on entrepreneurship intention. Based on the previous research, a research model and a research hypothesis were established. 251 questionnaire responses were collected through a survey of university students in Seoul and Gyeonggi Province and empirical analysis was performed using SPSS 24 and AMOS 23. As a result of the analysis, first, the autonomous motivation was found to have a positive effect on attitude, subjective norms, and perceived behavioral control. In addition, attitude, subjective norms, and perceived behavioral control all showed a positive effect on entrepreneurship intention. Entrepreneurship education for university students was found to control the effect of subjective norms on entrepreneurship intention and the effect of perceived behavioral control on entrepreneurship intention in the positive direction. The results of this study can contribute to the establishment of more effective educational policies and startup support program planning that can increase the entrepreneurial intention of university students.

• KDI Journal of Economic Policy
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• v.44 no.4
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• pp.25-42
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• 2022

I analyze how the food delivery market's indirect network effect and spillover effect influence the spread of food delivery platforms in different counties. This study finds that there is a positive local indirect network effect and a positive spillover effect in the adoption of the platform by examining the food delivery platform market in South Korea as of 2020. As food delivery platforms secure consumers who use them, more restaurants on the other side of a two-sided market adopt such platforms (indirect network effect). The spillover effect would allow other restaurants in a region to become more likely to adopt food delivery platforms if there are a greater number of restaurants in the region that use such platforms. This study contributes to the comprehension of technology diffusion and the marketing strategies of platform providers by providing empirical evidence of both effects.

• The Journal of Internal Korean Medicine
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• v.27 no.2
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• pp.316-326
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• 2006

Backgrounds & Objects: The aim of this study was to investigate the radioprotective effect of Shengmai-san(SMS), a herbal medicine, on mice jejunal crypt cell survival and Apoptosis. Methods: Mice were devided into 4 groups according to radiation dose and SMS treatment: Normal was the group without irradiation. Control was the group treated with D.W before 10 Gy irradiation. SMS 2.9 was sample group treated with 2.9 mg/10 g of SMS extract before 10 Gy irradiation and SMS 29 was sample group treated with 29 mg/10 g of SMS extract before 10 Gy irradiation. And Each group were sacrificedat 24 hours and 72 hours after irradiation. To analyze the crypt survival, hematoxylin-eosin staining was used and to analyze the apoptosis, the TUNEL assay was done. Results: 1. From the microcolony survival assay, the SMS 2.9 and SMS 29 showed the radioprotective effect with a statistical significance compared to the control group at 24 hr (P < 0.01) and 72 hr (p < 0.001) after 10 Gy irradiatien. And the differences of radioprotective effect between SMS 2.9 and SMS 29 were net significant. 2. The results of the TUNEL assay showed that the apoptotic index in SMS 2.9 and SMS 29 was significantly decreased, as compared to the control group at both 24 hr ( p < 0.01) and 72 hr (SMS 2.9 : p < 0.001. SMS 29 : P < 0.01) after 10Gy irradiation And the differences of between SMS 2.9 and SMS 29 were not significant. Conclusions: It could be suggested that the Shengmai-san has a prominent Protective effect in mice intestines against the radiation damage. And the radieprotective effect seems to be related to inhibition of the apoptosis.