• Journal of Engineering Education Research
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• 제25권2호
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• pp.32-41
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• 2022

The purpose of this study was in a pandemic situation caused by COVID-19 to explore the online distance experiments and interaction of engineering freshmen, and to identify practical difficulties, resulting in to derive implications. Seven freshmen from engineering college participated in the interview, of which data were analyzed based on phenomenological analysis methods. The types of non-face-to-face experiments experienced by students were complete non-face-to-face experiment, mixed face-to-face experiment, and fusion face-to-face experiment. Students were completely isolated in time and space in complete non-face-to-face experiment. In biweekly mixed face-to-face experiment, isolation was halved. In fusion face-to-face experiment, isolation was removed. Non-face-to-face interactions can be characterized by restrictions on simultaneous activities, on rapport formation, and on observation opportunities. Based on these results, three implications were derived: First, it is necessary to allow students to manage time and space constraints on their own in non-face-to-face experiments. Second, support is needed to solve the difficulty of forming rapport, which is a characteristic of non-face-to-face interaction. Third, an opportunity to observe the interaction between other students and professors should be provided.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제16권7호
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• pp.1370-1376
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• 2012

This paper proposes a gender recognition algorithm which classifies a male or female speaker. In this paper, characteristic vectors for the male and female speaker are analyzed, and recognition experiments for the proposed gender recognition by a neural network are performed using these characteristic vectors for the male and female. Input characteristic vectors of the proposed neural network are 10 LPC (Linear Predictive Coding) cepstrum coefficients, 12 LPC cepstrum coefficients, 12 FFT (Fast Fourier Transform) cepstrum coefficients and 1 RMS (Root Mean Square), and 12 LPC cepstrum coefficients and 8 FFT spectrum. The proposed neural network trained by 20-20-2 network are especially used in this experiment, using 12 LPC cepstrum coefficients and 8 FFT spectrum. From the experiment results, the average recognition rates obtained by the gender recognition algorithm is 99.8% for the male speaker and 96.5% for the female speaker.

• Journal of Korea Water Resources Association
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• 제43권4호
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• pp.399-408
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• 2010

The sensitivity of Nash model parameters is analyzed about characteristic velocities considering geomorphological dispersion in the present study. And changing shape of IUH compared and analyzed as variation of characteristic velocities through numerical experiment. Application watersheds are selected 4 subwatersheds which are located at main stream of Bocheong basin. The mean and variance of hillslope and stream path length are estimated in each watershed with GIS. And Nash model parameters are estimated with moments of path lengths and characteristic velocities. The changing trend about IUH which is derived Nash model parameters are compared as variation of characteristic velocities. The Major results of this study are summarized as follows. The Nash model parameters sensitively present changes about hillslope characteristic velocity. And the effect of the peak discharge and shape of recession in IUH dominate with hillslope's characteristic velocity, the effect of the peak time and shape of ascension in IUH dominate with channel's characteristic velocity.

• Nuclear Engineering and Technology
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• 제41권7호
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• pp.929-944
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• 2009

The present study is concerned with the extension of the Effective Convectivity Model (ECM) to the phase-change problem to simulate the dynamics of the melt pool formation in a Light Water Reactor (LWR) lower plenum during hypothetical severe accident progression. The ECM uses heat transfer characteristic velocities to describe turbulent natural convection of a melt pool. The simple approach of the ECM method allows implementing different models of the characteristic velocity in a mushy zone for non-eutectic mixtures. The Phase-change ECM (PECM) was examined using three models of the characteristic velocities in a mushy zone and its performance was compared. The PECM was validated using a dual-tier approach, namely validations against existing experimental data (the SIMECO experiment) and validations against results obtained from Computational Fluid Dynamics (CFD) simulations. The results predicted by the PECM implementing the linear dependency of mushy-zone characteristic velocity on fluid fraction are well agreed with the experimental correlation and CFD simulation results. The PECM was applied to simulation of melt pool formation heat transfer in a Pressurized Water Reactor (PWR) and Boiling Water Reactor (BWR) lower plenum. The study suggests that the PECM is an adequate and effective tool to compute the dynamics of core melt pool formation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권8호
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• pp.2974-2992
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• 2021

Crowd-based outsourcing is an emerging trend in testing, which integrates advantages of crowd-based outsourcing in software testing. Open call format is used to accomplish various network tasks involving different types of testing levels and techniques at various places by software testers. Crowd-sourced software testing can lead to an improper testing process as if it does not allocate the right task to the right crowd with required skills and not choose the right crowd; it can lead to huge results, which become time-consuming and challenging crowd-source manager for the identification of improper one. The primary purpose of this research is to make crowd-based outsourced software testing more effective and reliable by relating association between the software tester, personality characteristic, and different levels of software testing, i.e., unit, integration, and system, in order to find appropriate personality characteristic for required testing level. This research has shown an observed experiment to determine which software testing level suits which personality characteristic tester in a crowd-based software testing environment. A total of 1000 software testers from different software houses and firms in Pakistan were registered to perform tasks at different software testing levels. The Myers-Briggs Type Indicator (MBTI) test is used to identify each tester's personality characteristic involved in this research study.

• Journal of Mushroom
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• 제6권3_4호
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• pp.146-149
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• 2008

Pleurotus pulmonarius usually grows on the dead wood of deciduous trees in mid summer to early fall. The pileus color is white to tan and fruiting body is generally smaller than P. ostreatus. This study was carried out to investigate the characteristics of cultivation and consumer acceptance of P. pulmonarius. The period of incubation and primordial occurrence were required about 33days, 5days in bottle cultivation repectively, and the yield was 170g/850cc bottle. In bed cultivation, the period of primordial occurrence was similar to that of bottle cultivation and the yields was $35.7{\sim}46.2kg/3.3m^2$. Taste and favor of P. pulmonarius were superior to P. oostreatus., but the appearance, color and shape, was slightly inferior to P. ostreatus.

• Journal of the Korean Applied Science and Technology
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• 제26권1호
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• pp.51-59
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• 2009

Natural Artemisia extraction was extracted from Artemisia component using diethyl ether as a solvent, and we tested various pharmacetical and chemical characteristics of this extract. Characteristic experiments to use natural Artemisia extract tested antimicrobial experiment using microbe in pharmacetical material, and tested dye experiment using fiber in chemical material. From the result of characteristics experiment, some conclusions are obtained as follow. From the result of extraction experiment, it obtained about 10.4%-Artemisia extraction ratio as semi-solid state, and after dried in freezing from Artemisia extract of semi-solid state, it obtained about 10%-Artemisia extraction ratio as solid state of dark blue-green color. From result of antimicrobial experiment of Artemisia extract, number of staphylococcus aureus (ATCC-01) and aspergillus niger (ATCC-02) in microbe decreased more and more according to time passage. This phenomenon showed that Artemisia extract influences to antimicrobial effect. From the result of dye experiment of Artemisia extract, it appeared in direction of dark blue-green color after dyed to use cotton and silk with fiber to control in pH 7.5. Specially the result which confirmed dye of fiber with optical electron microscope (OEM), we could know that it appears darker silk than cotton.

• Journal of the Korean Applied Science and Technology
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• 제26권3호
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• pp.341-349
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• 2009

Natural grape extraction was extracted from grape component using diethyl ether as a solvent, and we tested various pharmaceutical and chemical characteristics of this extract. Characteristic experiments to use natural grape extract tested antimicrobial experiment using microbe in pharmaceutical material, and tested dye experiment using fiber in chemical material. From the result of characteristics experiment, some conclusions are obtained as follow. From the result of characteristics experiment, it obtained about 7.5%-grape extraction ratio as semi-solid state, and after dried in freezing from grape extract of semi-solid state, it obtained about 10%-grape extraction ratio as solid state of dark purple color. From result of antimicrobial experiment of grape extract, number of staphylococcus aureus (KCMC-01) and aspergillus niger (KCMC-02) in microbe decreased more and more according to time passage. This phenomenon showed that grape extract influences to antimicrobial effect. From the result of dye experiment of grape extract, it appeared in direction of dark purple color after dyed to use cotton and silk with fiber to control in pH 7.5. Specially the result which confirmed dye of fiber with optical electron microscope(OEM), we could know that it appears darker silk than cotton.

• The Transactions of The Korean Institute of Electrical Engineers
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• 제58권8호
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• pp.1624-1632
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• 2009

In this study, we introduce the design methodology of an optimized Interval Type-2 fuzzy controller. The fixed MF design of type-1 based FLC leads to the difficulty of rule-based control design for representing the linguistically uncertain expression. In the Type-2 FLC as the expanded type of Type-1 FLC, we can effectively improve the control characteristic by using the footprint of uncertainty(FOU) of membership function. Type-2 FLC has a robust characteristic in the unknown system with unspecific noise when compared with Type-1 FLC. Through computer simulation as well as practical experiment, we compare their performance by applying both the optimized Type-1 and Type-2 fuzzy cascade controllers to ball and beam system. To evaluate each controller performance, we consider controller characteristic parameters such as maximum overshoot, delay time, rise time, settling time and steady-state error.

• Journal of the Korean Society for Precision Engineering
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• 제22권8호
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• pp.108-117
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• 2005

In modern industrial society, many kinds of valves have been used to control fluid flow. For the optimization of a ball valve, a quarter of spherical ball was modeled and evaluated. However, there is a difficulty in the application of the optimization technique because of the complexity of the fluid and the restriction of analysis. Therefore, in this study, it is performed to evaluate the stability of an initial model using FEM(Finite Element Method) and CFD. In addition, a shape optimization design of the valve is accomplished using an orthogonal arrangement and characteristic functions. From the result, a new design method is represented that could overcome the time and space restriction in structural design, such as the divided ball valve with less experiment.