• 한국식품위생안전성학회지
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• 제9권4호
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• pp.213-220
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• 1994

Customary usage of oil at homes and rancidity of edible soybean oil by cooking frequency at homes and mass meal services were investigated. 80% of house wives bought the cooking oil by 1.8ι unit container and 70% of them read either the manufactured date or explanatory note for use. 85% of house wives kept oil in the storage case under sink or in the pantry chest, and 80% of oils were used once or twice and 20% used three times for cooking. Acid value(AV), iodine value(IV), peroxide value(POV), carbonyl value(CoV) and thiobarbituric acid value(TBAV) of fresh soybean oil were lower than standard level. In the rancidity by cooking frequency, the acid value, peroxide value, carbonyl value and thiobarbituric acid value increased significantly when oil was used once and iodine value decreased significantly when used once and twice at both mass meal services and homes. The level of the acid value, iodine value, carbonyl value and thiobarbituric acid value of oil used at mass meal services did not show significant difference from those of oil used at homes. But, the peroxide value of oil used thrice at mass meal services was significantly higher than those of homes.

• 한국수산과학회지
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• 제51권3호
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• pp.305-312
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• 2018

This study was carried out to investigate euphausiid abundance in an acoustic survey from March 2010 to July 2010 to suggest reasonable usage and management of the euphausiid Euphausia pacifica in the coastal area of Guryongpo Pohang. The acoustic data were analyzed by the 2-frequency difference method and the distorted wave born approximation acoustical theoretical model, which is used for organisms of weak target strength with small scatter, such as euphausiid scatter, among other marine organisms. The distribution and monthly density of euphausiids were estimated in the survey area. The results show that the volume back scattering strength frequency difference for euphausiid was 13.91-7.6 dB, and their monthly averag density was $28.2g/m^2$.

• 인지과학
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• 제11권3_4호
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• pp.57-72
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• 2000

최근 국내에서도 기억 및 표상 연구에서 그림자극을 사용하는 예가 증가하기 시작하면서 한국판 그림자극 규준이 필요하게 되었다. 본 논문에서는 그림과 단어처리의인지적 기제를 밝히려하거나 그림을 자극으로 사용하는 기억연구를 위해 한국판 그림자극 규준을 제시한다. 본 규준은 213개의 그림들과 이 그림들에 대한 명명일치도, 표현적절성, 친숙도 평정자료, 그리고 이전 연구들에서 다루어진 관련 변인들(빈도, 범주, 범주빈도)의 정리를 포함한다. 아울러, 최근의 암묵기억과 외현기억 연구들에서 논의되고 있는 변인들을 중심으로 본 자극 세트의 제한점을 살펴보고, 응용범위에 대해 고찰해 본다.

• 대한기계학회논문집A
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• 제21권12호
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• pp.2068-2072
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• 1997

Acoustic noise has become an increasingly important issue, especially in the industrial environment. Nowadays home and office are not exceptional, mainly due to the increase in the usage of machinery. Active Noise Control(ANC) becomes efficiently an available tool for the noise suppression with rapid advances of solid state electronics. In this study an ANC system is developed for audio headphone to work as a noise protector, so called an ear-muff. The system is developed to kill a certain frequency band noises selectively which is purposed to suppress only the dominant ambient noise such that normal numan conversation is not disturbed with wearing the ear-muff. For the purpose, an ANC design strategy is suggested and implemented with an analogue control circuit. The performance is evaluated by frequency response test, which shows well consistence with theoretical one. The results are so satisfactory that noise of 640 Hz, which is aimed to suppress, is reduced by 20db without significant distortion in other frequency band.

• Structural Engineering and Mechanics
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• 제22권2호
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• pp.185-195
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• 2006

Nowadays it is very necessary to generate artificial accelerograms because of lack of adequate earthquake records and vast usage of time-history dynamic analysis to calculate responses of structures. According to the lack of natural records, the best choice is to use proper artificial earthquake records for the specified design zone. These records should be generated in a way that would contain seismic properties of a vast area and therefore could be applied as design records. The main objective of this paper is to present a new method based on wavelet theory to generate more artificial earthquake records, which are compatible with target spectrum. Wavelets are able to decompose time series to several levels that each level covers a specific range of frequencies. If an accelerogram is transformed by Fourier transform to frequency domain, then wavelets are considered as a transform in time-scale domain which frequency has been changed to scale in the recent domain. Since wavelet theory separates each signal, it is able to generate so many artificial records having the same target spectrum.

• 한국보건간호학회지
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• 제33권1호
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• pp.47-58
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• 2019

Purpose: Regarding the rapid growth of the obesity in Korea's youths, environmental factors as well as biological tendencies have been major focus of years of study. Methods: This study, as a secondary analysis research, bases its source upon the raw data from the 13th on-line survey of the Korean adolescents' health behaviors. In particular, it is a descriptive research for clarifying the relevance of the Korean youths' smart phone use with their health behaviors and obesity. Results: In logistic analysis, variables showing a significant difference are as follows: soft drinks frequency(p<.001), sweet drinks intake frequency(p<.001), fast food intake frequency(p<.001) and smoking status (p=.005). Based on the amount of time the teenagers using smart phones, there have been different results in the risk of obesity. Four to six hours a week of smart phone use (p=.002) has a 1.132 times higher risk, six to eight hours(p<.001) are 1.212 times higher, over eight hours(p=.020) are 1.132 times higher, than less than two hours'. Conclusion: This study has significance in that it has emphasized the new lifestyle, teenagers' smart phone use, as an additional important factor for the increased risk of obesity.

• ETRI Journal
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• 제46권3호
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• pp.392-403
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• 2024

Even though generalized frequency division multiplexing is an alternative waveform method expected to replace the orthogonal frequency division multiplexing in the future, its implementation must alleviate channel effects. Least-squares (LS), a low-complexity channel estimation technique, could be improved by using the discrete Fourier transform (DFT) without increasing complexity. Unlike the usage of the LS method, the DFT-based method requires the receiver to know the channel impulse response (CIR) length, which is unknown. This study introduces a simple, yet effective, CIR length estimator by utilizing LS estimation. As the cyclic prefix (CP) length is commonly set to be longer than the CIR length, it is possible to search through the first samples if CP is larger than a threshold set using the remaining samples. An adaptive scale is also designed to lower the error probability of the estimation, and a simple signal-to-interference-noise ratio estimation is also proposed by utilizing a sparse preamble to support the use of the scale. A software simulation is used to show the ability of the proposed system to estimate the CIR length. Due to shorter CIR length of rural area, the performance is slightly poorer compared to urban environment. Nevertheless, satisfactory performance is shown for both environments.

• Journal of the Korean Data and Information Science Society
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• 제23권5호
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• pp.927-937
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• 2012

본 연구는 특수교사들의 정보통신기술 (ICT; information & communication technology) 활용에 관한 실태 및 인식을 알아보기 위하여 특수교사들을 대상으로 설문조사를 실시하였다. 총 103부의 설문지를 토대로 교사들의 ICT 활용 현황과 수업에서 ICT 활용에 대한 태도와 시각, ICT 활용과 관련된 교원 연수의 필요성과 연수에 필요한 교육 내용을 분석하였다. 특히 ICT의 활용 교과목이 대학의 특수교육과에 반영된 시점을 기준으로 교직경력을 구분하여 그 차이를 검증하였으며 두 집단에 대한 ICT 활용 현황과 수준은 차이가 있는 것으로 분석되었다.

• 제어로봇시스템학회논문지
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• 제15권6호
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• pp.641-648
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• 2009

Currently several kinds of sensor localization methods have been developed for terrestrial wireless sensor networks. This study, in order to extend the field to underwater environments, a localization technique is studied for UWSNs (Underwater Wireless Sensor Networks). In underwater environments, RF (Radio Frequency) signal is not suitable for underwater usage because of extremely limited propagation. Because of that reason UWSNs should be constituted with acoustic modems. But, to realize underwater application, we can borrow many design principles from ongoing research for terrestrial environments. So, in this paper we introduce the modified localization algorithm using ToA method which is based on the terrestrial research. First of all, we study the localization techniques for terrestrial environments where we investigate possible methods to underwater environment. And then the appropriate algorithm is presented in the underwater usage. Finally the proposed underwater based localization algorithm is evaluated by using computer.

• 수산해양교육연구
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• 제27권5호
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• pp.1273-1289
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• 2015

The purpose of this study was to use the parent of the infant status and their media perception (3-7 five years) the infants' media use by examining the situation looking at the parents' use of media that cause impact on infants' media use parents will be validated accordingly to seek the solutions for the media and the involvement of infants perception. U City and 14 practitioners in preschool infants aged 5-7 target parents from 1307 people based in September 2014, a survey was conducted two months until October. This study was a mixed Methods for quantitative analysis of all the results and qualitative analysis of the results. Results for media use quantitative analysis of the results and impact parents have on infants' media use their media usage status of the parents and the media use of infants by their perceived status has been subjected to frequency analysis and hierarchical multiple regression analysis, parents perception results. Analysis of the solution for the immersion of the media and the infants unit of analysis was used for componential analysis. Through this study, parents would like to establish a plan to take advantage of essential educational content in the media and sought ways for the correct use of infants in the media and practice at home.