• 한국소음진동공학회논문집
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• 제13권8호
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• pp.583-590
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• 2003

For the preestimate of the vibration level of the ground next to a dwelling, a multivariate statistical analysis on the experiment data acquired from a variety of construction sites was performed, and then a new estimate model for the value of K and n that can be applied in the diagnosis of the damage was offered. The results maybe summarized as follows : First, the $K_{95}$ and n showed high correlation at P$\leq$0.05. Specially the correlation coefficient about $W_{max}$, S were higher in $K_{95}$ than in n. indicating that $K_{95}$ is generally associated with source conditions. Second, the factor analysis permitted to identify two major sources in each fraction. These sources accounted for at least 73 % of valiance of $K_{95}$. Third, the multiple regression model for the estimate of $K_{95}$ was developed from Fac1 which depend upon the source conditions and Fac2 which depend upon the transmission conditions. The n value is able to determine from the correlation relationship associated with $K_{95}$./.

• 전기학회논문지
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• 제60권8호
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• pp.1599-1605
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• 2011

From now on, power line communication was made use of controling using 450 kHz narrow band, but as the PLC technology developing, in the near future get to the commercial step that is broadband PLC upto 30 MHz. In this paper, analyze the possibility of moving picture transmission for adapting surveillance camera which is among of the application of PLC. To analyze characteristics of channel, estimate the noise and impedance of lab, office, home. In case of noise, there is no problem to communicate each other because of 20 ~ 50 dB gain. In case of impedance, average impedance is about 100 ohm, it satisfy standards of designing modem but because max and min values get out of expectation there are some problem to acquire fully capacity of modems. Its condition is the same as transmission of multimedia data. In this test as more packets, as more handling rate, in lab, for the case that transmit 1,518 byte as the speed of 6 Mbps handling rate is upto 100%, it means possibility of moving picture transmission as the 6 Mbps speed. For delayed time there is no relationship about transmitted packets. As a result, there is no problem about applying surveillance camera via the PLC. And more cameras can work within PLC for considering the number of transmitted frames.

• Earthquakes and Structures
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• 제3권1호
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• pp.1-15
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• 2012

An empirical predictive relationship correlating bracketed duration to earthquake magnitude, site-to-source distance, and local site conditions (i.e. rock vs. stiff soil) for stable continental regions of North America is presented herein. The correlation was developed from data from 620 horizontal motions for central and eastern North America (CENA), consisting of 28 recorded motions and 592 scaled motions. The bracketed duration data was comprised of nonzero and zero durations. The non-linear mixed-effects regression technique was used to fit a predictive model to the nonzero duration data. To account for the zero duration data, logistic regression was conducted to model the probability of zero duration occurrences. Then, the probability models were applied as weighting functions to the NLME regression results. Comparing the bracketed durations for CENA motions with those from active shallow crustal regions (e.g. western North America: WNA), the motions in CENA have longer bracketed durations than those in the WNA. Especially for larger magnitudes at far distances, the bracketed durations in CENA tend to be significantly longer than those in WNA.

• Journal of Nutrition and Health
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• 제29권9호
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• pp.1028-1034
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• 1996

This study examined within-and between-individual variation in nutrient intakes in order to estimate the degrees of precison in dietary assessment among 59 female volunteers aged 21-23 years. Self-recorded 7-day dietary recalls and records were collected by during a 3 month period. Between the recall and record methods, there were little difference of within-and between-individual variations. Within-to-between individual variation ratios were > 2.0 for most of the nutrients examined, and were higher for niacin, vitamin A and C (>2.5) in the recals and for calcium, iron, vitamin A and C(>3.0) in the records. With 7-day dietary data, observed nutrient intakes were estimated to within 26-107% of the subjects' true(usual) intakes, among those vitamin C and energy showed the highest and lowest values, respectively. Correlation coefficients between observed and true nutrient intakes were 0.73-0.81 for the recalls and 0.68-0.77 for the records. In order to estimate with 20% precision, 12-13 days of dietary study were required for energy, 46 for calcium, 71-72 for vitamin A, and 199-200 for vitamin C. Attenuation factor ranged 0.73-0.81 for the recalls and 0.68-0.77 for the records. This study implies that commonly used 1 or 3 day dietary studies may not be appropriate for assessing individuals' nutrient intakes. Further research focusing on the methodological issues in the assessment of Korean diet are needed for between understanding of the relationship between diet and health in Koreans.

• 한국지하수토양환경학회지:지하수토양환경
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• 제21권3호
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• pp.88-94
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• 2016

The simultaneous biodegradation between MTBE (Gasoline additives) and BTEX (Benzene, Toluene, Ethyl-benzene, o-Xylene, m-Xylene, p-Xylene) was achieved within a competitive inter-relationship, with not only electron accepters such as nitrate, sulfate, and iron(III) without oxygen, but also with electron donors such as MTBE and BTEX. Preexisting indigenous microorganisms from a domestic sample of gasoline contaminated soil was used for a lab-scale batch test. The result of the test showed that the biodegradation rate of MTBE decreased when there was co-existing MTBE and BTEX, compared to having just MTBE present. The growth of indigenous microorganisms was not affected in the case of the MTBE treatment, whereas the growth of the microorganisms was decreased in combined MTBE and BTEX sample. This may indicate that an inhibitor related to biodegradation when BTEX and MTBE are mixed will be found. This inhibitor may be found to retard the anaerobic conditions needed for efficient breakdown of these complex carbon chain molecules in-situ. Moreover, it is also possible that an unknown competitive reaction is being imposed on the interactions between MTBE and BTEX dependent on conditions, ratios of mixture, etc.

• Asian-Australasian Journal of Animal Sciences
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• 제17권7호
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• pp.954-959
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• 2004

In a herd of 24 spring-born steers, plasma leptin and performance of selected purebred (n=5) and backcrossed Hereford (n=5) were compared in a year-round summer grazing and winter feedlot fattening. Bimonthly blood collection and body weight measurement were accomplished. The plasma samples were analyzed for leptin, insulin, total cholesterol, triglyceride, NEFA and glucose. The experimental design utilized one-way ANOVA with breed as the treatment. The purebred obtained higher plasma NEFA (p<0.001) compared to backcross, regardless of seasonal feeding systems (SFS). The backcross showed gradual increase and nonresponsiveness of plasma leptin to SFS. During summer grazing, attenuation of plasma leptin and sudden elevation when shifted to winter feedlot fattening were observed in purebred. Plasma leptin obtained linear relationship with body weight of purebred (r=0.53;p<0.001) and backcrossed Hereford (r=0.49; p<0.01). The purebred and backcrossed Hereford, when shifted to summer grazing, resulted to sustained and restricted daily gain, respectively. Therefore, cattle breeds of higher growth potential exhibit significant elevation of plasma leptin after 400 kg BW, when animal starts to deposit significant body fat.

• 한국지진공학회논문집
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• 제7권2호
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• pp.93-102
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• 2003

지진 하중을 받는 전체 네트워크 시스템 및 네트워크 구성 절점에 대한 신뢰성 지수를 구할 수 있는 지진 재해 신뢰성 평가 방법을 전력 송전 네트워크 시스템을 대상으로 개발하였다. 전력 송전 시스템에 대하여 절점과 링크로 구성된 네트워크 모형을 개발하였으며, 절점인 변전소의 지진 취약도 곡선은 변전소 구성 기기의 개별 취약도 곡선으로부터 구하였다. 입력 지진 모형으로서 점 지진원 모형을 사용하였고, doubly truncated Gutenberg-Richter 관계식과 감쇠공식을 적용하였다. 몬테 카를로 시뮬레이션을 적용하여 전력 송전 네트워크 시스템의 신뢰성을 평가한 결과 한국의 전력망에 대한 지진 재해의 효과는 무시할 수 있는 수준은 아닌것으로 평가되었다.

• 대한기계학회논문집A
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• 제26권4호
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• pp.745-753
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• 2002

It is required to evaluate nondestructively the crack depth of surface-breaking cracks for the assurance of safety of structure. Optical generation of ultrasound produces well defined pulses with a repeatable frequency content, that are free of any mechanical resonances; they are broad band and are ideal for the measurement of attenuation and scattering over a wide frequency range. Self-calibrating surface signal transmission measurement is very sensitive and practical tool for surface-breaking crack depth. In this paper, the self-calibrating technique by laser-based ultrasound is used to evaluate the depth of surface-breaking crack of material. It is suggested that the relationship between the signal transmission and crack depth can be used as a practical model for predicting the surface-breaking crack depths from the signal transmission measured in structure.

• International Journal of Computer Science & Network Security
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• 제22권3호
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• pp.382-388
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• 2022

Satellite communication for high altitude platform stations (HAPS) and low earth orbit (LEO) systems suffer from dust and sand (DU&SA) storms in the desert regions such as Saudi Arabia. These attenuations have a distorting effect on signal fidelity at high frequency of operations. This results signal to noise ratio (SNR) to dramatically decreasing and leads to wireless transmission error. The main focus in this paper is to propose common relations between HAPS and LEO for the atmospheric impairments affecting the satellite communication networks operating above Ku-band crossing the propagation path. A double phase three dimensional relationship for HAPS and LEO systems is then presented. The comparison model present the analysis of atmospheric attenuation with specific focus on sand and dust based on particular size, visibility, adding gaseous effects for different frequency, and propagation angle to provide system operations with a predicted vision of satellite parameters' values. Skillful decision and control system (SD&CS) is proposed to control applied parameters that lead to improve satellite network performance and to get the ultimate receiving wireless signal under bad weather condition.

• Asian Journal for Public Opinion Research
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• 제8권4호
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• pp.432-452
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• 2020

This study explored the representation of risks from the controversial Lynas rare earth refining as a risk event by five Malaysian online mainstream and alternative newspapers using qualitative content analysis. The aim is to uncover the role of the news media in the social amplification and attenuation of risks within the literature evidence as those roles are still uncertain. Content analysis is used to explore the online newspapers' roles guided by the Social Amplification of Risk Framework (SARF). The representations typified environmental, financial, health, occupational, property, radioactive, and technological risks and established connections between four risk types (environmental, financial, radioactive, and health risks). Radioactive risk was repeatedly associated with other risks, suggesting that the volume and information flow focused on radioactive risk as a key ingredient for amplification. This connection shows that the nature of the relationship between risks is multidimensional, contradicting the unidirectional type found in previous studies. Alternative online newspapers amplified and attenuated more risks, thus, providing more diverse coverage than mainstream sources. Consequently, this study provides evidence that risk representation from rare earth refining in a digital news environment is multidimensional and intensified or weakened in a multi-layered pattern. The stakeholders are engaged in a contestation by positioning their narratives to oppose or support their interests, which are amplified or attenuated by the online newspapers as social amplification stations.