• JSTS:Journal of Semiconductor Technology and Science
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• 제10권1호
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• pp.28-36
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• 2010

Hardware implementation methods for Artificial Neural Network (ANN) have been researched for a long time to achieve high performance. We have proposed a Network on Chip (NoC) for ANN, and this architecture can reduce communication load and increase performance when an implemented ANN is small. In this paper, a multiple NoC models are proposed for ANN, which can implement both a small size ANN and a large size one. The simulation result shows that the proposed multiple NoC models can reduce communication load, increase system performance of connection-per-second (CPS), and reduce system running time compared with the existing hardware ANN. Furthermore, this architecture is reconfigurable and reparable. It can be used to implement different applications of ANN.

• 한국통신학회논문지
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• 제34권12B호
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• pp.1444-1451
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• 2009

본 논문은 EPCglobal C1 Gen 2 표준에서 제안한 Q 알고리즘에서 사용되는 C값에 대한 다양한 모델을 제시하고 시뮬레이션을 통하여 그 성능을 비교, 평가한다. EPCglobal C1 Gen 2 표준에서는 다중 태그 인식을 위해서 slot-count (Q) Selection Algorithm을 제안하고 있지만, Q 알고리즘에서 태그의 충돌과 무응답의 상태에 따라서 Q값을 변화시키는 값인 C 값에 대한 정확한 정의가 내려져 있지 않다. Q 알고리즘에서는 태그 충돌의 경우 C를 Q에 더하고 무응답인 경우에는 C를 감산하여 변화되는 Q값으로 태그들의 새로운 slot-count를 결정하기 때문에 다중 태그 인식 환경에 있어서 이 C값은 태그 인식 속도에 커다란 영향을 준다. 하지만 기존 연구들에서는 C값에 따른 태그 인식 속도 성능 평가나 비교 없이, Q 알고리즘을 변형하거나 새로운 방법을 제안하여 태그 인식 속도를 늘리기 위한 연구들이 존재한다. 본 연구에서는 EPCglobal C1 Gen 2 표준을 만족하는 C값의 다양한 모델을 제시하고 각각에 대해 다중 태그 인식 환경에 있어서 그 성능을 비교하고 평가한다. 본 연구의 결과물은 향후 EPCglobal C1 Gen 2 C 모델에 대한 연구나 태그 인식 성능 연구를 위한 하나의 지표로 쓰일 수 있다.

• 대한수의학회지
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• 제61권2호
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• pp.12.1-12.9
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• 2021

The mosquito-borne pathogen Zika virus may result in neurological disorders such as Guillain-Barré syndrome and microcephaly. The virus is classified as a member of the Flaviviridae family and its wide spread in multiple continents is a significant threat to public health. So, there is a need to develop animal models to examine the pathogenesis of the disease and to develop vaccines. To examine the clinical profile during Zika virus infection, we infected neonatal and adult wild-type mice (C57BL/6 and Balb/c) and compared the clinical signs of African-lineage strain (MR766) and Asian-lineage strain (PRVABC59, MEX2-81) of Zika virus. Consistent with previous reports, eight-week-old female Balb/c mice infected with these viral strains showed no changes in body weight, survival rate, and neurologic signs, but demonstrated increases in the weights of spleens and hearts. However, one-day-old neonates showed significantly lower survival rate and body weight with the African-lineage strain than the Asian-lineage strain. These results confirmed the pathogenic differences between Zika virus strains. We also evaluated the clinical responses in neonatal and adult mice of different strains. Our findings suggest that these are useful mouse models for characterization of Zika virus for vaccine development.

• Journal of Ecology and Environment
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• 제33권2호
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• pp.165-173
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• 2010

Soil respiration ($R_S$) is a critical component of the annual carbon balance of forests, but few studies thus far have attempted to evaluate empirical regression models in $R_S$. The principal objectives of this study were to evaluate the relationship between $R_S$ rates and soil temperature (ST) and soil water content (SWC) in soil from a cool-temperate deciduous broad-leaved forest, and to evaluate empirical regression models for the prediction of $R_S$ using ST and SWC. We have been measuring $R_S$, using an open-flow gas-exchange system with an infrared gas analyzer during the snowfree season from 1999 to 2001 at the Takayama Forest, Japan. To evaluate the empirical regression models used for the prediction of $R_S$, we compared a simple exponential regression (flux = $ae^{bt}$Eq. [1]) and two polynomial multiple-regression models (flux = $ae^{bt}{\times}({\theta}{\nu}-c){\times}(d-{\theta}{\nu})^f:$ Eq. [2] and flux = $ae^{bt}{\times}(1-(1-({\theta}{\nu}/c))^2)$: Eq. [3]) that included two variables (ST: t and SWC: ${\theta}{\nu}$) and that utilized hourly data for $R_S$. In general, daily mean $R_S$ rates were positively well-correlated with ST, but no significant correlations were observed with any significant frequency between the ST and $R_S$ rates on periods of a day based on the hourly $R_S$ data. Eq. (2) has many more site-specific parameters than Eq. (3) and resulted in some significant underestimation. The empirical regression, Eq. (3) was best explained by temporal variations, as it provided a more unbiased fit to the data compared to Eq. (2). The Eq. (3) (ST $\times$ SWC function) also increased the predictive ability as compared to Eq. (1) (only ST exponential function), increasing the $R^2$ from 0.71 to 0.78.

• International Journal of Concrete Structures and Materials
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• 제7권4호
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• pp.303-317
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• 2013

This study evaluates the shear strength of steel fiber reinforced concrete (SFRC) beams from a database, which consists of extensive experimental results of 222 SFRC beams having no stirrups. In order to predict the analytical shear strength of the SFRC beams more precisely, the selected beams were sorted into six different groups based on their ultimate concrete strength (low strength with $f_c^{\prime}$ <50 MPa and high strength with $f_c^{\prime}$ <50 MPa), span-depth ratio (shallow beam with $a/d{\geq}2.5 $and deep beam with a/d<2.5) and steel fiber shape (plain, crimped and hooked). Principal component and multiple regression analyses were performed to determine the most feasible model in predicting the shear strength of SFRC beams. A variety of statistical analyses were conducted, and compared with those of the existing equations in estimating the shear strength of SFRC beams. The results showed that the recommended empirical equations were best suited to assess the shear strength of SFRC beams more accurately as compared to those obtained by the previously developed models.

• Laboraroty Animal Research
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• 제34권4호
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• pp.232-238
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• 2018

Animal models have been used to elucidate the pathophysiology of varying diseases and to provide insight into potential targets for therapeutic intervention. Although alternatives to animal testing have been proposed to help overcome potential drawbacks related to animal experiments and avoid ethical issues, their use remains vital for the testing of new drug candidates and to identify the most effective strategies for therapeutic intervention. Particularly, the study of metabolic diseases requires the use of animal models to monitor whole-body physiology. In line with this, the National Institute of Food and Drug Safety Evaluation (NIFDS) in Korea has established their own animal strains to help evaluate both efficacy and safety during new drug development. The objective of this study was to characterize the response of C57BL/6NKorl mice from the NIFDS compared with that of other mice originating from the USA and Japan in a chemical-induced diabetic condition. Multiple low-dose treatments with streptozotocin were used to generate a type-1 diabetic animal model which is closely linked to the known clinical pathology of this disease. There were no significantly different responses observed between the varying streptozotocin-induced type-1 diabetic models tested in this study. When comparing control and diabetic mice, increases in liver weight and disturbances in serum amino acids levels of diabetic mice were most remarkable. Although the relationship between type-1 diabetes and BCAA has not been elucidated in this study, the results, which reveal a characteristic increase in diabetic mice of all origins are considered worthy of further study.

• 한국통신학회논문지
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• 제38C권1호
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• pp.57-63
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• 2013

본 논문에서는 통신 시뮬레이터인 OPNET을 두 개 이상의 실체계와 연동하기 위하여 필요한 게이트웨이 모델의 구현 방법을 제안한다. 일반적으로 두 개 이상의 실체계가 시뮬레이터와 연동하기 위해서는 시뮬레이터 외부에서 스위치를 이용하여 실체계들을 단일 링크로 구성한 후 시뮬레이터와 연결하여야 한다. 이는 시뮬레이터와 실체계가 독립적인 송수신기를 가지고 이동성을 가지지 않는 형태로 모델링 되는 경우에 가능한 방법이다. 시뮬레이터가 실체계의 일부 모듈을 모델링하고 이동성을 가지는 경우에는 기존의 방법을 사용할 수 없다. 본 논문에서는 이러한 경우에 사용될 수 있는 연동 게이트웨이 모델을 구현하는 방법을 제안한다. 본 논문에서 제안하는 방법은 OPNET에서 제공하는 SITL 게이트웨이 모델에 리모트 인터럽트를 통한 패킷 교환을 위한 모듈을 추가함으로써 구현된다.

• Advances in aircraft and spacecraft science
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• 제1권4호
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• pp.427-441
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• 2014

Orbit-raising is an important step to place spacecraft from parking orbits into working orbits. Attitude control system design is crucial in the success of orbit-raising. Several text books have discussed this design and focused mainly on the traditional methods based on single-input single-output (SISO) transfer function models. These models are not good representations for many orbit-raising control systems which have multiple thrusters and each thruster has impact on the attitude defined by all outputs. Only one published article is known to use a more suitable multi-input multi-output (MIMO) Euler angle model in spacecraft orbit-raising attitude control system design. In this paper, a quaternion based MIMO model for the orbit-raising attitude control system design is proposed. The advantages of using quaternion based model for orbit-raising control system designs are (a) there is no need for mathematical transformations because the attitude measurements are normally given by quaternion, (b) quaternion based model does not depend on rotational sequences, which reduces the chance of human errors, and (c) the singular point of reduced quaternion model is the farthest from the operational point where linearization is performed. We will show that performance of quaternion model based design will be as good as the performance of Euler angle model based design for orbit-raising problem.

• The Journal of Asian Finance, Economics and Business
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• 제6권3호
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• pp.305-313
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• 2019

The study examines whether higher CEO compensation is related to unobserved future firm performance in an emerging market, Pakistan. Further, it extends its scope to analyzing the impact of group affiliation and ownership concentration on the relationship between CEO compensation and future firm performance. The study uses an unbalanced panel data consisting of 1508 firm-year observations from 225 non-financial listed companies in Pakistan Stock Exchange (PSX) for period 2005 to 2012. The multiple regression models adjusted to heteroskedasticity and autocorrelation in error terms are used. The study finds that, in general, CEO compensation is positively associated with future operating performance. However, higher CEO compensation leads to lower operating performance in firms that have lower ownership concentration and are affiliated with business groups. When firms are not affiliated with any group and have high ownership concentration, the relationship between excessive CEO compensation and future operating performance becomes insignificant. Given that efficient compensation packages may lead to long term value creation to shareholders and reduce agency problems, this study highlights an important moderating role of ownership concentration and group affiliation of the firms in emerging markets.

• 한국식품과학회지
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• 제30권2호
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• pp.341-347
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• 1998

본 연구에서는 서로 다른 동결조건 및 방법에 따른 우육 및 tylose의 단순하며 간편한 동결시간을 예측할 수 있는 모델을 모색하기 위하여 23개의 실험데이터를 이용하여 시료의 초기온도$(X_1)$, 시료의 두께$(X_2)$와 시료의 초기빙결점에서 동결매체 온도사이의 차의 역수$(X_3)$ 및 표면열전달계수의 역수$(X_4)$를 독립변수로 하고 동결시간(Y)을 종속변수로 설정하여 다중회귀 분석을 실시한 결과, $Y_{tylose}=3.45X_1+7642.84X_2+4642.67X_3+2946.89X_4-431.33\;(R^2=0.9568)$ 및 $Y_{beef}=0.68X_1+7568.98X_2+2430.78X_3+3293.26X_4-299.00\;(R^2=0.9897)$의 방정식을 구하였다. 본 모델은 Cleland & Earle와 Hung & Thompson의 모델과 마찬가지로 평균절대오차는 10% 수준으로, Plank, Nagaoka 및 Pham의 모델보다 정확함과 아울러 매우 간편함을 보여 주었다. 또한, 우육 및 tylose의 $6{\sim}7^{\circ}C$ 범위에서의 열확산율은 $4.43{\times}10^{-4}m^2/hr$ 및 $4.39{\times}10^{-4}m^2/hr,\;-10{\sim}-12^{\circ}C$에서의 열확산율은 $2.42{\times}10^{-3}m^2/hr$ 및 $3.32{\times}10^{-3}m^2/hr$로 측정되었고, tylose 및 우육의 빙결점은 각각 $-0.6^{\circ}C$ 및 $-1.2^{\circ}C$로 나타났다. 그리고 표면열전달계수는 송풍식에서 무포장시 $20.57\;W/m^2^{\circ}C$, wrap 포장시는 $16.11\;W/m^2^{\circ}C$, wrap 과 Al-foil로 포장한 경우에는 $13.07\;W/m^2^{\circ}C$로 계산되었으며, 침지식은 송풍식보다 냉각속도가 약 10배 이상 빠르게 나타났다.