• 전자공학회논문지CI
• /
• 제49권1호
• /
• pp.16-22
• /
• 2012

본 논문에서는 알츠하이머병이 유도된 형질전환 마우스로부터 획득한 혈소판 라만 스펙트럼의 분석을 위해 가우시안 모델을 이용한 커브 피팅으로 기준선을 추정하고 보정하는 방법을 제안하였다. 측정된 라만 스펙트럼은 의미 있는 정보와 불필요한 노이즈 성분인 기준선과 가산 노이즈를 포함하고 있다. 스펙트럼의 효율적인 분석을 위해 노이즈를 포함하고 있는 스펙트럼을 몇 개의 피크를 포함하는 영역으로 분할하고 각 로컬 영역의 스펙트럼을 가우시안 모델을 이용한 커브 피팅으로 모델링한다. 가산 노이즈는 원 스펙트럼을 이 델로 대체하는 과정에서 명백하게 제거된다. 피팅된 모델의 로컬 최저점을 linear, piecewise cubic Hermite, cubic spline 알고리즘으로 보간하고 기준선을 보정한다. 기준선을 보정한 피팅 모델은 PCA(principal component analysis) 방법을 이용하여 특징을 추출하고 SVM(support vector machine)과 MAP(maximum $a$ posteriori probability) 분류 방법으로 성능 비교 실험을 하였다. 실험 결과에 따르면 linear 보간법이 모든 주성분 수에 대한 분류율의 평균에서 우세하였고 특히 piecewise cubic Hermite 보간법은 주성분의 수가 5개인 경우에서 SVM 분류율이 약 97.3%로 가장 좋은 성능을 보였다. 또한 이전의 연구 결과와 비교를 통해 제안한 기준선 보정 방법이 혈소판 라만 스펙트럼의 분석에 효과적으로 적용될 수 있음을 확인하였다.

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

• 한국통신학회논문지
• /
• 제26권12A호
• /
• pp.1971-1977
• /
• 2001

이동무선통신환경에서의 다중경로 레일레이 페이딩 채널은 선형 필터 모델로 나타내어 질 수 있고, 지연 경로의 특성에 따라 필터 탭 중 일부만이 수신기 설계에 있어 중요하게 고려될 수 있다. 지연경로를 나타내는 탭 계수의 크기에 따라 채널 등화기에서 선택적으로 탭을 사용함으로써 수신기의 복잡도를 감소시키고 사용 전력을 줄이는 효과를 가져오게 된다. 본 논문에서는 주어진 채널의 선형 필터 모델에서 최적의 방법으로 탭을 선택하는 방법을 제시하고, 기존의 방법과 비교하여 성능 향상을 보였다. 또한 잡음 전력 값에 대한 정보가 있는 경우, 제시된 방법은 CFAR (Constant False Alarm Rate) 판별의 장점을 가지게 됨을 보이고, 잡음 전력을 추정했을 시의 성능을 정확한 수식으로 유도하였다. 잡음 전력 추정을 위한 잡음 샘플 수를 증가시킴에 따라 빠른 속도로 최적 성능으로 수렴함을 유도된 수식과 시뮬레이션 결과를 통해 확인하였다.

• Journal of applied mathematics & informatics
• /
• 제41권4호
• /
• pp.861-868
• /
• 2023

Nonlinear network creates complex homotopy structural communication in wireless network medium because of complex distribution approach. Due to this multicast topological connection structure, the queuing probability was non regular principles to create routing structures. To resolve this problem, we propose a Co-cluster homotopy queuing model (Co-CHQT) for Nonlinear Algebraic Topological Structure (NLTS-) for improving poison distribution network communication. Initially this collects the routing propagation based on Nonlinear Distance Theory (NLDT) to estimate the nearest neighbor network nodes undernon linear at x_(a,b)→ax²+bx² = c. Then Quillen Network Decomposition Theorem (QNDT) was applied to sustain the non-regular routing propagation to create cluster path. Each cluster be form with co variance structure based on Two unicast 2(n+1)-Z2(n+1)-Z network. Based on the poison distribution theory X_(a,b) ≠ µ(C), at number of distribution routing strategies weights are estimated based on node response rate. Deriving shorte;'l/st path from behavioral of the node response, Hilbert -Krylov subspace clustering estimates the Cluster Head (CH) to the routing head. This solves the approximation routing strategy from the nonlinear communication depending on Max- equivalence theory (Max-T). This proposed system improves communication to construction topological cluster based on optimized level to produce better performance in distance theory, throughput latency in non-variation delay tolerant.

• International Journal of Reliability and Applications
• /
• 제5권1호
• /
• pp.25-36
• /
• 2004

Ultrasonic inspection system consist of the examination procedures, equipment, and operators. The reliability of nondestructive testing is influenced by the inspection environment, materials and types of defect. It is very difficult to estimate the reliability of NDT due to the various factors. Piping inspection round robin was conducted to quantify the capability of ultrasonic inspection during in-service. In this study, the models for predicting the ultrasonic NDE reliability by logistic model and linear regression model are discussed. The utility of the NDT reliability assessment is verified by the analysis of the data from round robin test with these models.

• 대한원격탐사학회지
• /
• 제13권2호
• /
• pp.121-132
• /
• 1997

본 논문에서는 위성영상으로부터 수치표고모형 추출을 목적으로 하는 영상정합 알고리즘 의 개발에 관하여 기술한다. 개발된 알고리즘은 주어진 목적에 맞추어 비선형 최소자승법에 기초 한 영역정합방식에 기초하였으나 새롭게 정의된 정합구역을 이용함으로써 기존의 정합방식보다 향상된 정합 수행속도를 가진다. 이 정합 알고리즘은 정합수행 모듈, 정합조절 모듈, 정합최적화 모듈로 구성되어 있으며 각각의 기능에 대하여 기술한다. 또한 제안된 알고리즘의 성능을 정합 가능도, 수행 속도, 정합 수렴 반경 등을 이용하여 정량적으로 분석한다.

• 한국항공우주학회지
• /
• 제33권2호
• /
• pp.32-38
• /
• 2005

본 연구에서는 근사모델을 이용하여 설계공간의 타당성을 높일 수 있는 방법을 제시하였다. 이때 설계공간을 이동시키기 위한 기준으로 Chebyshev Inequality를 사용하였다. 이를 공탄성을 고려한 항공기 익형 설계문제에 적용함으로써 타당성이 크게 향상됨을 확인하였으며 이렇게 구한 설계공간 내에서 최적화를 수행함으로써 보다 우수한 최적값도 얻을 수 있었다. 즉 설계공간 내에서 주어진 제약조건을 만족할 확률이 증가하였으며, 설계공간을 이동시킴으로써 보다 우수한 최적점이 설계공간 내에 포함되었다고 할 수 있다. 또한 이 과정에서 반응면 모델과 크리깅 모델, 두 가지 근사모델을 사용하여 정확성과 효율성, 실험점에 대한 강건성 등을 비교하였으며, 본 연구에서 설계한 문제의 경우 비교적 선형적인 특징으로 인해 반응면이 보다 우수한 결과를 보여줌을 확인하였다.

• Wind and Structures
• /
• 제31권3호
• /
• pp.217-227
• /
• 2020

Based on translation models, both Gaussian and non-Gaussian wind fields are generated using spectral representation method for investigating the influence of non-Gaussian characteristics and directivity effect of wind load on fatigue damage of wind turbine. Using the blade aerodynamic model and multi-body dynamics, dynamic responses are calculated. Using linear damage accumulation theory and linear crack propagation theory, crack initiation life and crack propagation life are discussed with consideration of the joint probability density distribution of the wind direction and mean wind speed in detail. The result shows that non-Gaussian characteristics of wind load have less influence on fatigue life of wind turbine in the area with smaller annual mean wind speeds. Whereas, the influence becomes significant with the increase of the annual mean wind speed. When the annual mean wind speeds are 7 m/s and 9 m/s at hub height of 90 m, the crack initiation lives under softening non-Gaussian wind decrease by 10% compared with Gaussian wind fields or at higher hub height. The study indicates that the consideration of the influence of softening non-Gaussian characteristics of wind inflows can significantly decrease the fatigue life, and, if neglected, it can result in non-conservative fatigue life estimates for the areas with higher annual mean wind speeds.

• Smart Structures and Systems
• /
• 제24권4호
• /
• pp.507-524
• /
• 2019

A Bayesian dynamic linear model (BDLM) is presented for a data-driven analysis for response prediction and load effect separation of a revolving auditorium structure, where the main loads are self-weight and dead loads, temperature load, and audience load. Analyses are carried out based on the long-term monitoring data for static strains on several key members of the structure. Three improvements are introduced to the ordinary regression BDLM, which are a classificatory regression term to address the temporary audience load effect, improved inference for the variance of observation noise to be updated continuously, and component discount factors for effective load effect separation. The effects of those improvements are evaluated regarding the root mean square errors, standard deviations, and 95% confidence intervals of the predictions. Bayes factors are used for evaluating the probability distributions of the predictions, which are essential to structural condition assessments, such as outlier identification and reliability analysis. The performance of the present BDLM has been successfully verified based on the simulated data and the real data obtained from the structural health monitoring system installed on the revolving structure.

• 경영과학
• /
• 제25권1호
• /
• pp.139-147
• /
• 2008

Conjoint Analysis is marketers' favorite methodology for finding out how buyers make trade-offs among competing products and suppliers. Thousands of applications of conjoint analysis have been carried out over the past three decades. The conjoint analysis has been so popular as a management decision tool due to the availability of a choice simulator. A conjoint simulator enables managers to perform 'what if' question accompanying the output of a conjoint study. Traditionally the First Choice Model (FCM) has been widely used as a choice simulator. The FCM is simple to do, easy to understand. In the FCM, the probability of an alternative is zero until its value is greater than others in the set. Once its value exceeds that threshold, however, it receives 100%. The LOGIT simulation model, which is also called as "Share of Preference", has been used commonly as an alternative of the FCM. In the model part worth utilities aren't required to be positive. Besides, it doesn't require part worth utilities computed under LOGIT model. The simulator can be used based on regression, monotone regression, linear programming, and so on. However, it is not free from the Independent from Irrelevant Alternatives (IIA) problem. This paper proposes the EBA (Elimination-By-Aspects) model as a useful conjoint-like method. One advantage of the EBA model is that it models choice in terms of the actual psychological processes that might be taking place. According to EBA, when choosing from choice objects, a person chooses one of the aspects that are effective for the objects and eliminates all objects which do not have this aspect. This process continues until only one alternative remains.