• Journal of the Korean Wood Science and Technology
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• 제49권6호
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• pp.541-549
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• 2021

This paper reports a method to evaluate the residual strength of insect-damaged radiata pine lumber, such as the screw withdrawal strength as a semi-destructive method and a compression parallel to the grain test to assess the density changes after exposure to outdoor conditions. The screw withdrawal strength test was used as a semi-destructive method to estimate the residual density of decayed lumber. A compression parallel to the grain test was applied to evaluate the residual density. Three variables, such as the screw withdrawal strength, compression parallel to the grain, and residual density, were analyzed statistically to evaluate their relationships. The relationship between the residual density and screw withdrawal strength showed a good correlation, in which the screw withdrawal strength decreased with decreasing density. The other relationship between the residual density and compression parallel to the grain was also positively correlated; the compression parallel to the grain strength decreased with decreasing density. Finally, the correlation between the three variables was statistically significant, and the mutual correlation coefficients showed a strong correlation between the three variables. Hence, these variables are closely correlated. The test results showed that the screw withdrawal strength could be used as a semi-destructive method for an in situ estimation of an existing wood structure. Moreover, the method might approximate the residual density and compression parallel to the grain if supplemented with additional data.

• Communications for Statistical Applications and Methods
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• 제14권2호
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• pp.301-307
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• 2007

A effective teaching method on correlation coefficient for elementary level statistics course is discussed in this article. The well known inequalities, such as Theorem 368 of Hardy et al. (1952), are used for the interpretation of concept of covariance. An Excel example is provided for the illustration of concept of correlation coefficient.

• 전자공학회논문지B
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• 제33B권6호
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• pp.64-72
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• 1996

In this paper, we propose predictive motion estimatin algorithm which can predict motion without additional side information considering spatio-tempral correlatio of motion vector. This method performs motion prediction of current block using correlation of the motion vector for two spatially adjacent blocks and a temporally adjacent block. Form predicted motion, the position of searhc area is determined. Then in this searhc area, we estimate motion vector of current block using block matching algoirthm. Considering spatial an temporal correlation of motion vector, the proposed method can predict motion precisely much more. Especially when the motion of objects is rapid, this method can estimate motion more precisely without reducing block size or increasing search area. Futhrmore, the proposed method has computation time the same as conventional block matching algorithm. And as it predicts motion from adjacent blocks, it does not require additional side information for adjacent block. Computer simulation results show that motion estimation of proposed method is more precise than that of conventioanl method.

• ETRI Journal
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• 제40권3호
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• pp.303-308
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• 2018

This paper proposes a simple yet accurate method for estimating the antenna correlation coefficient (ACC) of a high-order multiple-input multiple-output (MIMO) antenna. The conventional method employed to obtain the ACC from three-dimensional radiation patterns is costly and difficult to measure. An alternate method is to use the S-parameters, which can be easily measured using a network analyzer. However, this method assumes that the antennas are highly efficient, and it is therefore not suitable for lossy MIMO antenna arrays. To overcome this limitation, we define and utilize the non-coupled radiation efficiency in the S-parameter-based ACC formula. The accuracy of the proposed method is verified by the simulation results of a 4-port highly coupled lossy MIMO array. Further, the proposed method can be applied to N-port arrays by expanding the calculation matrix.

• 한국환경보건학회지
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• 제33권5호
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• pp.422-427
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• 2007

The purposes of this study were to investigate the concentration of total coliforms in sewage effluents during the period from August 2004 to October 2005. The removal efficiency range of multi-tube method and plate count method were $31.3{\sim}99.5%$ and $66.8{\sim}99.2%$, respectively. Though a correlation between the multi-tube method and the plate count method in the same sample is low, not only is an experimental procedure very simple, but the time required also is short. The seasonal correlation between methods showed more sensitive spring and summer than autumn and winter. So the study indicated plate count method can be used in rapid and reliance identification of total coliform more than the multi-tube method.

• 설비공학논문집
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• 제14권10호
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• pp.854-862
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• 2002

In the previous research, a simplified correlation method was developed as an easy prediction tool for comparing energy use of cooling plants. The purpose of this paper is to test the applicability of this method for economic evaluation with two zones of a 20-story commercial building in Seoul. The results of this method were compared with the DOE-2 simulation and actual measured data. Then, Comparisons of life cycle cost were carried out for three types of cooling plants. Testing of one zone showed good agreement of within 10% error in cooling energy use and within 2% error in LCC. But testing of the other zone indicated that the use of this method were invalid when input variables were used beyond its valid range.

• 한국구조물진단유지관리공학회 논문집
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• 제3권2호
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• pp.177-183
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• 1999

The major object of this study is to investigate experimentally the experimental equation by the non-destructive testing methods of ultrasonic pulse velocity, rebound number, combined method of ultrasonic pulse velocity and rebound number, maturity which are applicable to the evaluation of compressive strength of concrete at early ages. Also test result of mix are statistically analyzed to infer the correlation coefficient between the maturity and the compressive strength of concrete. The results show good application of Logistic curve for estimating strength development under various curing temperature. The relation between ultrasonic pulse velocity, rebound number, combined method of ultrasonic pulse velocity and rebound number and compressive strength of concrete have low correlation coefficient, but maturity method show good correlation coefficient.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.81-85
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• 1999

DWMT VDSL system needs A/D converter clock, bit clock, symbol clock, frame clock, etc. DMT ADSL system utilizes a correlation method which makes use of cyclic prefix or preamble pattern for clock recovery. But the correlation method is difficult to apply to the DWMT system because modulated symbols are overlapped in the time domain. This paper proposes a novel clock recovery method which can be used for the DWMT system due to its inherent independence of the modulation method. This new method is verified by SPICE simulations.

• ETRI Journal
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• 제19권4호
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• pp.389-401
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• 1997

In this paper, we consider the relationship between nonlinearity and correlation immunity of Boolean functions. In particular, we discuss the nonlinearity of correlation immune functions suggested by P. Camion et al. For the analysis of such functions, we present a simple method of generating the same set of functions, which makes it possible to construct correlation immune functions with controllable correlation immunity and nonlinearity. Also, we find a bound for the correlation immunity of functions having maximal nonlinearity.

• 한국정보과학회논문지:정보통신
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• 제30권4호
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• pp.504-512
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• 2003

본 논문에서는 디졸브 모델링 오차를 이용한 디졸브 검출 방법을 제안한다. 디졸브 모델링 오차는 디졸브 구간을 구성하는 두 장면 사이에 상관성이 없는 이상적인 디졸브 모델과 상관성이 존재하는 실제 디졸브 사이의 차이로 정의된다. 제안된 방법은 두 단계로 구성된다. 첫 번째 단계에서는 분산 곡선에서 나타나는 디졸브 구간의 특성인 아래로 볼록한 포물선을 검출하여 디졸브 후보 구간을 설정한다. 두 번째 단계에서는 선택된 후보 구간 자각에 대해 디졸브 모델링 오차를 정의하고 모델링 오차가 기준치와 비교한다. 기준치는 목표 모델링 오차로 각 후보 구간의 분산과 사용자에 의해 주어지는 목표 상관성에 대한 함수로 표현됨으로 제안된 기준치, 목표 모델링 오차는 각 후보 구간의 분산 변화에 적응적이다. 제안한 디졸브 검출 방법은 디졸브 구간을 구성하는 두 장면의 상관성을 고려하므로, 의미론적 디졸브 검출 방법이 될 수 있다. 제안된 방법을 다양한 동영상에 적용하여 성능을 평가하였다. 실험 결과 제안한 방법이 다양한 분산의 변화에도 불구하고 기존의 방법보다 정확하고 신뢰성 높은 디졸브 검출 결과를 나타내었다.