• Journal of the Korean GEO-environmental Society
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• v.7 no.2
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• pp.25-32
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• 2006

The deformation modulus of rock masse is a very important design factor for the computation of stability of tunnels and their support systems. Several empirical formulas to estimate the deformation modulus using simple rock classification methods such as RQD or RMR are widely used because field tests to evaluate the deformation modulus are very expensive and time consuming work. However, these formulas can be depended on experiences from the characteristics of local sites in each country. Therefore, in this study, the applicability of empirical formulas was analyzed by comparing estimated value with the measured value from eight sites in South Korea. The results show that the estimated value based on the empirical formulas partially have tendency to overestimate. Especially, in case of sedimentary rocks, it was too difficult to apply to the empirical formulas because there was no relationship between estimated value and measured value. For these reasons, additional data from many tests and accurate analyses are necessary to evaluate the estimation method for the deformation modulus considering the local characteristics of rock masse.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2017.11a
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• pp.51-53
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• 2017

본 논문은 프레임 율 향상을 위한 움직임 추정 알고리듬을 제안한다. 양방향 움직임 추정은 중첩 영역이나 홀 (hole) 영역이 발생하지 않지만 물체의 실제 움직임을 찾는 데에 어려움이 있다. 이중 움직임 추정 방법은 이를 어느정도 해결하였지만 여전히 실제 물체의 이동과는 다른 움직임 벡터들이 남아있다. 움직임 벡터의 정확도를 향상시키기 위해 기존의 이중 움직임 추정 알고리듬을 토대로 SMD (side matching distortion)를 움직임 추정 매칭 식에 결합한 새로운 매칭 기준 식을 제안한다. 결과적으로 제안하는 알고리듬은 기존의 이중움직임 추정 방법에 비해 정량적으로 PSNR (peark signal-to-noise ratio)이 크게 향상되었으며 주관적으로도 뛰어난 결과를 보여주었다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.4
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• pp.25-34
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• 2015

Proposed equation is used many time in calculation of concrete compressive strength using the non-destructive testing at precision safety diagnosis. Most of proposed equation is suggested in abroad and have an error to estimate concrete compressive strength in the domestic. Therefor, proposed equation is low reliability to estimate concrete compressive and it has a significant effect in reliability of precision safety diagnosis. Nevertheless, It is possible to increase the reliability through a number of experiments from this problem that occurs in some localized part. This paper is proposed assessment formula of reliability related core compressive strength to increase the reliability. It is verified that reliability of proposed assessment formula is useful by probabilistic techniques. It is compared with each graphs of concrete compressive strength of proposed equation. It has been found that the present methods are very efficient.

• Journal of Korean Society of Transportation
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• v.20 no.4
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• pp.123-134
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• 2002

감응식 신호운영변수 설계에 관한 연구는 정주기식 신호운영변수 설계의 그것보다 그 수준이 현저히 미비하며 이는 감응식 신호운영 특성을 반영한 평가방법의 부재로 감응식 운영변수의 평가가 불가능하였기 때문이다. 본 논문은 최근에 소개된 평균 감응현시 녹색시간 추정 수리모형을 이용하여 Highway Capacity Manual (HCM) 지체도를 최소화하는 최대녹색시간의 설계방안을 제시한다. - '최소녹색시간'과 '단위연장시간'은 보행자 횡단시간 및 차량 차두시간 등 지역별 운전자/보행자의 특성과 관련이 있어 일반적인 최적화 설계 수리모형의 적용에 무리가 있어 제외한다. 제안된 설계방안은 감응식 운영논리를 토대로 감응현시 군의 평균녹색시간과 평균주기를 산정하며, HCM 지체도를 평가하고, 가능한 대안 중 지체를 최소화하는 최대녹색시간 운영변수 군을 '혼혈 유전자 알고리즘'으로 도출한다. 현장실험을 통해 도출이 불가능한 실제 최적치를 Corridor Simulation(CORSIM)모형을 이용하여 추정하였고 이를 제안된 설계방안으로 도출된 최대녹색시간 운영변수' 값들과 비교하였다. 비교결과 교차로 v/c 비율이 1.0 보다 낮을 시는 제안된 방법을 통해 설계된 최대녹색시간 운영변수 군이 최소 CORSIM 지체도를 산출하는 최대녹색시간 운영변수 군과 동일한 것으로, v/c비율이 1.0보다 높을 시는 다른 것으로 결과되었다. v/c비율이 1.0 보다 높은 경우는 정주기식 교차로 운영에 효율적이라 감응식 운영의 필요를 벗어나므로 제안된 최대녹색시간 설계방안은 감응식 신호운영 필요범위 내에서 효율적이다. 기존의 최대녹색시간 설계는 정수기식 최적녹색시간을 기준으로 최대녹색시간을 추정하며, 그러한 과정을 돕기 위하여 추정범위(설계자가 범위 내에서 임의로 선택함)를 제시하는 것이 기존의 연구임을 비교하면 본 연구에서 제안하고 있는 설계방법의 의미가 크다.

• The Journal of the Acoustical Society of Korea
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• v.20 no.8
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• pp.58-66
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• 2001

In this paper, a computationally efficient time delay and doppler estimation algorithm is proposed for active sonar with Linear Frequency Modulated (LFM) signal. To reduce the computational burden of the conventional estimation algorithm, an algebraic equation is used which represents the relationship between the time delay and doppler in cross-ambiguity function of the LFM signal. The algebraic equation is derived based on the Fast maximum Likelihood (FML) method. Using this algebraic relation, the time delay and doppler are estimated with two 1-D search instead of the conventional 2-D search. The estimation errors of the proposed algorithm are analyzed for various SNR's. The simulation result demonstrates the good performance of the proposed algorithm.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2732-2734
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• 2003

본 논문에서는 낮은 공간 해상도로의 디지털 비디오 변환 부호화기에 대한 움직임 벡터 추정 기법을 제안한다. 블록 정합 에러가 테일러 급수 전개에 의한 참조 블록의 복잡도에 비례한다는 사실에 근거하여 새로운 움직임 벡터 평가식을 유도하여 변환 부호화기에 대한 움직임 벡터를 이 평가식에 의해 추정한다. 제안한 방법에 의해 추정된 움직임 벡터들은 기존 방법에 의해 추정된 벡터보다 최적 벡터에 더 인접하였으며, 부호화된 영상은 더 좋은 화질을 보인다. 특히 빠른 움직임을 포함하는 영상에서 제안된 방법의 우수성은 더 두드러진다.

• Journal of the Korea Institute of Building Construction
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• v.16 no.3
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• pp.229-235
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• 2016

In construction field, it used various technique for concrete formwork. Part of them, non-destructive test has been conducted to estimate a compressive strength of concrete easily such as rebound method and ultrasonic pulse velocity method etc. Former research has recommend proposed equation based on experimental data to investigate strength of concrete but it was sometimes deferent actual value of that from in field because of the few of data in case of early strength concrete. In this study, an experiment was conducted to analyze strength properties for early strength concrete using cylinder mold and $1,000mm{\times}1,000mm{\times}200mm$ rectangular specimen. And compressive strength of concrete was tested by non-destructive test, and calculated by the equation proposed former research. As a result, the non-destructive test results showed approximately 70 percent of the failure test value for all conditions, and worse reliability was obtained for high strength concrete samples when the ultrasonic pulse velocity method was used. Based on the scope of this study, the experimental equation for estimating compressive strength of early strength concrete from 24MPa to 60MPa was proposed.

• The Journal of the Acoustical Society of Korea
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• v.16 no.3
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• pp.81-85
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• 1997

In this paper, a recursive estimation algorithm for FIR systems is proposed using the 3rd and 4th order cumulants. To obtain the Overdetermined Recursive Instrumental Variable(ORIV) method type algorithm, we transform the 3'th and 4'th order cumulant relationship to a certain matrix form which is consist of only output data. From the matrix form, we induce the proposed algorithm procedure following the ORIV method. The proposed algorithm provides improved estimation accuracy with smaller data and can be applied to a time varying system as well. In addition, it reduces the estimation error due to the additive Gaussian noise compared to conventional 2'rd order based algorithms since it only uses higher than 2'rd order cumulant. Simulation results are presented to compare the performance with other HOS-based algorithms.

• Communications for Statistical Applications and Methods
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• v.4 no.1
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• pp.301-310
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• 1997

본 연구에서는 비(ratio)에 대한 2차잭나이프 추정량을 제안하고, 그것의 편의와 분산이 집단의 수에 대한 감소함수임을 보인다. 또한, 이 추정량의 우수성을 편의와 평균제곱오차의 측면에서 기존의 추정량과 비교 분석한다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.4
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• pp.71-78
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• 2007

Schmidt hammer and ultra-sonic method are commonly used for crushed sand concrete compressive strength test in a construction field. At present, various of equations for prediction of strength are present, which have been used in a construction field. The purpose of this study is to evaluate the correlation between prediction strength by presentation equations and destructive strength to test specimen, and find out which is a suitable equation for the construction site. In this study, a strength test was carried out destructive test by means of core sampling and traditional test. The experimental parameter were concrete age, curing condition, and strength level.