• Membrane Journal
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• v.27 no.6
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• pp.519-527
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• 2017

Membrane fouling is the main issue hindering the expansion of low pressure membrane processes for surface water treatment. Therefore, applying periodic hydraulic cleaning for fouling control should be well optimized. Better understanding of membrane fouling associated with periodic hydraulic cleaning would be useful to optimize membrane cleaning strategies. By comparing experimental permeability data with the classical Hermia blocking laws, this study aims at analyzing membrane fouling and understanding dominant fouling mechanisms occurring when filtering a synthetic surface water solution with a pressurized membrane process during six filtration cycles of 30 min each, separated with cyclic cleaning of 1 min by backwashing and forward flushing separately and combined. When applying single cleaning technique, membrane fouling during the first cycles was controlled by complete blocking mechanism while the last cycles were dominated by cake formation. Nevertheless, when combining cleaning technique better membrane regeneration was obtained and fouling was mainly due to cake formation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.3
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• pp.296-304
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• 1998

A design method of an electromagnetic wave absorber with ferrite fins in the second layer, which has very wide band frequency characteristics and is used for single-polarized wave absorption such as TV wave etc, has been designed. To examine the effectiveness of the Equivalent Material Constants Method$(EMCM)^{[1]}$ which is approximate method, the effective complex permittivity calculated by the Hashin-Strikman formulas and the EMCM are compared. Since, furthermore, the reflectivities by the EMCM in space and the FDTD method in an rectangular waveguide agreed well each other, it has been confirmed that the proposed electromagnetic wave absorber has excellent absorption characteristics in the frequency range of 30 MHz to 5830 MHz. Thus, it can be concluded that the EMCM is usefull to design and analyze the electro-magnetic wave absorber proposed here.

• Journal of the Korean Home Economics Association
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• v.47 no.5
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• pp.23-34
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• 2009

The purpose of this study was to e${\times}$amine the effect of visual imagery stimulated by product information on consumer responses in online shopping conte${\times}$ts. Dual coding theory provided the theoretical framework of the study. The proposed model of the study was e${\times}$amined by conducting an e${\times}$periment using mock apparel websites with a between-subject factorial design: [2 (pictorial information: detailed views vs. no detailed views) ${\times}$ 2 (verbal information: detailed descriptions vs. abstract descriptions)]. A total of 439 female college students participated in the e${\times}$periment, and 433 responses were ultimately used to test the hypotheses. The findings from the results revealed: (1) the main effects of the pictorial and verbal information on visual imagery, and (2) positive relationships between (a) visual imagery and mood, (b) visual imagery and perceived product quality, (c) mood and perceived product quality, and (d) perceived quality and purchase intentions.

• Journal of Elementary Mathematics Education in Korea
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• v.24 no.2
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• pp.231-257
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• 2020

As the main mathematical concepts are presented and expressed in various ways through textbooks during the teaching and learning process, it is necessary to look at the representations used in elementary math textbooks to find effective guidance. This study analyzed sentences used in the definition of mathematical terms and unit assessments of current elementary mathematics textbooks according to word depth (Yngve, 1960) from a syntactic perspective. As a result of the analysis, it could be seen that the sentences in textbook were generally concise, the word depth was lower, and the sentence structure and form were different depending on the individual characteristics of each term. Also, the sentences in the lower grade textbooks were more easily constructed, and the sentences of the term definition were more complex than the sentences of the unit assessments. Efforts should be made to help learners learn mathematical concepts, such as clarifying sentences in textbooks, presenting visual materials together, and providing additional explanations to suit the level of individual learners.

• KIISE Transactions on Computing Practices
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• v.21 no.11
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• pp.727-732
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• 2015

These days, many researchers are working on Future Internet and a new networking paradigm called Software Defined Networking draws a great attention. In this paper, we redefine Software Defined Networking as Service Defined Networking which means that packets are categorized according to types of services. By using Service Defined Networking, we are not only dealing with the way to utilize the network resources efficiently but we also propose an algorithm to minimize the waiting time for packets to be delivered. This proposed algorithm can solve the delay problem, one of the most significant problems caused by network congestion. Also, since we are adopting Service Defined Networking, network resource utilization can be improved compared to the existing network.

• Korean Security Journal
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• no.43
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• pp.99-120
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• 2015

This research aimed at analyzing health behavior of private security guards applying planned behavioral theory. In order to achieve the above purpose, this research conducted purposive sampling on the security guards who live in Seoul Gyeonggi region. Excluding unfaithful response and abnormal outlier, material of 187 persons was used for analysis. As the concrete analysis method, multiple regression analysis and logistic regression analysis to presume exploratory factory analysis(EFA), Polyserial Exploratory Factor Analysis(EFA), Polyserial correlation analysis, and causal relationship between each variable. The result can be summarized as follows. First, attachment, attitude subjective standard on behavior, perceived behavioral control appeared to positively influence affirmative(+) effect on health behavior continuance will. Second, attachment had no meaningful influence attitude toward behavior. Third, attachment had affirmative(+) influence on health behavior continuance will. Fourth, perceived behavioral control had affirmative(+) influence on realization of health behavior, possibility of practising health behavior increased by about 62.9% when perceived behavioral control increased by 1 unit.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.1
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• pp.105-111
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• 2013

The spindle is the main component in machine tools. The static and dynamic characteristics of the spindle directly affect the machining accuracy of workpieces. The characteristics of the spindle depend on the shaft size, bearing span, built-in motor location, and so on. Therefore, the appropriate selection of these parameters is important to improve the spindle characteristics. This paper presents the analysis of the static and dynamic characteristics and optimization design of a 40,000-rpm high-speed spindle. Statistical analysis for optimization and finite element analysis were performed. This study uses the response surface method to optimize the objective function and design factors. The targets are the natural frequency and displacement. The design factors are the shaft length, shaft diameter, bearing span, and motor location. The optimized design provides better results than the initial model, and these results are expected to improve the static and dynamic characteristics of the spindle.

• Journal of the Institute of Convergence Signal Processing
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• v.12 no.2
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• pp.113-118
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• 2011

In this paper, we develop a speaker gender classification technique using collaborative sensor fusion for use in a wireless sensor network. The distributed sensor nodes remove the unwanted input data using the BER(Band Energy Ration) based voice activity detection, process only the relevant data, and transmit the hard labeled decisions to the fusion center where a global decision fusion is carried out. This takes advantages of power consumption and network resource management. The Bayesian sensor fusion and the global weighting decision fusion methods are proposed to achieve the gender classification. As the number of the sensor nodes varies, the Bayesian sensor fusion yields the best classification accuracy using the optimal operating points of the ROC(Receiver Operating Characteristic) curves_ For the weights used in the global decision fusion, the BER and MCL(Mutual Confidence Level) are employed to effectively combined at the fusion center. The simulation results show that as the number of the sensor nodes increases, the classification accuracy was even more improved in the low SNR(Signal to Noise Ration) condition.

• The Journal of the Korea Contents Association
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• v.9 no.9
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• pp.243-248
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• 2009

Among 74 patients who came to pain clinic to treat their backache, 37 patient were randomly allocated to experimental(finger-pressure therapy)group and another 37 patients were allocated to control(transcutaneous electrical nerve stimulator)group. The extent of backache was compared before and after experiment by ANCOVA test at both groups(p<0.005). The reduction of pain level by visual analogue scale at experimental group was statistically significantly bigger than control group when motion with front flexion(1.92), extension after front flexion(2.22), right flexion(1.23), and left flexion(1.21)(p<0.05).

• The Journal of the Korea Contents Association
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• v.19 no.10
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• pp.698-711
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• 2019

The purpose of this study was to investigate the effect of social servicescape on customer satisfaction, customer trust, and customer loyalty. Data were collected from 311 adults who lived in Daegu where they had used Japanese restaurants. For data analysis, frequency analysis, factor analysis, regression analysis and multiple regression analysis were used. Through the factor analysis, the social servicescape of Japanese restaurant was identified as two components of human service and customer similarity. As a result of the multiple regression analysis, two components of social servicescape have positive effects on customer satisfaction and customer trust, and have a partial positive effect on customer loyalty. The results of regression analysis showed that customer satisfaction had a positive effect on customer trust and customer loyalty. In addition, customer trust has a positive effect on customer loyalty. The results of this study confirmed the influence of social servicescape on Japanese specialty restaurants and suggested practical and theoretical implications.