• Structural Engineering and Mechanics
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• v.59 no.6
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• pp.1037-1054
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• 2016

Structural parameter evaluation and external force estimation are two important parts of structural health monitoring. But the structural parameter identification with limited input information is still a challenging problem. A new simultaneous identification method in time domain is proposed in this study to identify the structural parameters and evaluate the external force. Each sampling point in the time history of external force is taken as the unknowns in force evaluation. To reduce the number of unknowns for force evaluation the time domain measurements are divided into several windows. In each time window the structural excitation is decomposed by orthogonal polynomials. The time-variant excitation can be represented approximately by the linear combination of these orthogonal bases. Structural parameters and the coefficients of decomposition are added to the state variable to be identified. The extended Kalman filter (EKF) is augmented and selected as the mathematical tool for the implementation of state variable evaluation. The proposed method is validated numerically with simulation studies of a time-invariant linear structure, a hysteretic nonlinear structure and a time-variant linear shear frame, respectively. Results from the simulation studies indicate that the proposed method is capable of identifying the dynamic load and structural parameters fairly accurately. This method could also identify the time-variant and nonlinear structural parameter even with contaminated incomplete measurement.

• Journal of the East Asian Society of Dietary Life
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• v.1 no.3
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• pp.305-311
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• 1991

The study was designed to investigate overall acceptability of rice extrudate with added ginseng flour extruded by single screw extruder. Graphic three dimension analysis on response surface regression was conducted for overall acceptability evaluated by balanced incomplete block design. Overall acceptability, which formed a saddle point, increased as moisture content increased at lower die temperature, and as moisture content decreased at higher die temperature. Critical values of each variable which indicated optimum response are 5.0% ginseng content, 17.8% moisture content and 104.6$^{\circ}C$ die temperature, and optimum inferred score of overall acceptability is 59.6 and 90. Key words: extrdate, overall acceptability, response surface regression analysis, balanced incomplete block method.

• Proceedings of the Korean Reliability Society Conference
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• 2005.06a
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• pp.265-269
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• 2005

Cox's proportional hazards model (PHM) has been widely applied in the analysis of lifetime data, and it can be characterized by the baseline hazard function and covariates influencing systems' lifetime, where the covariates describe operating environments (e.g. temperature, pressure, humidity). In this article, we consider the constant baseline hazard function and a discrete random variable of a covariate. The estimation procedure is developed in a parametric framework when there are not only complete data but also incomplete one. The Expectation-Maximization (EM) algorithm is employed to handle the incomplete data problem. Simulation results are presented to illustrate the accuracy and some properties of the estimation results.

• Journal of Information Technology Applications and Management
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• v.11 no.2
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• pp.149-166
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• 2004

In the wake of Fishbein and Ajzen's the Theory of Reasoned Action (TRA), Davis (1989) proposed a Technology Acceptance Model (TAM) to account for how perceived ease of use, perceived usefulness, and attitude predict behavioral intention to use Information Systems (IS). However, TAM is incomplete in one important respect: it does not account for social influence In the acceptance and utilization of new information systems. This study investigated the relationships between organizational tasks and intention to use internet using TAM. For using internet, social network is an important factor because the natural characteristic of internet is community-based. The results showed that Organizational Culture (OC) plays an important role in explaining intention to use the internet. Using O'Reilly et al. 's measurements, we extended and empirically validated the proposed model using Structured Equation Modeling (SEM). These findings enable future researchers and practitioners to apply the OC variable in the various contextual domains.

• Communications for Statistical Applications and Methods
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• v.26 no.4
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• pp.371-383
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• 2019

Panel data sets have been developed in various areas, and many recent studies have analyzed panel, or longitudinal data sets. Maximum likelihood (ML) may be the most common statistical method for analyzing panel data models; however, the inference based on the ML estimate will have an inflated Type I error because the ML method tends to give a downwardly biased estimate of variance components when the sample size is small. The under estimation could be severe when data is incomplete. This paper proposes the restricted maximum likelihood (REML) method for a random effects panel data model with a censored dependent variable. Note that the likelihood function of the model is complex in that it includes a multidimensional integral. Many authors proposed to use integral approximation methods for the computation of likelihood function; however, it is well known that integral approximation methods are inadequate for high dimensional integrals in practice. This paper introduces to use the moments of truncated multivariate normal random vector for the calculation of multidimensional integral. In addition, a proper asymptotic standard error of REML estimate is given.

• Journal of the Semiconductor & Display Technology
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• v.22 no.2
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• pp.64-71
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• 2023

If an impedance mismatch occurs between the source and load in a Radio Frequency transmission system, reflected power is generated. This results in incomplete power transmission and the generation of Reflected Power, which returns to the Radio Frequency generator. To minimize this Reflected Power, Impedance matching is performed. Fast and efficient Impedance matching, along with converging reflected power towards zero, is advantageous for achieving desired plasma characteristics in semiconductor processes. This paper explores Impedance matching by adjusting the Vacuum Variable Capacitor of an L-type Matching Module based on the trends observed in the voltage of the Phase Sensor and Electromotive Force voltage. After assessing the impedance matching characteristics, the findings are described.

• The Research Journal of the Costume Culture
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• v.12 no.2
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• pp.199-210
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• 2004

This study was intended to identify the differences in perception of image words and perception dimension of desired image according to sex variable for college students in a school context. Data were collected by questionnaires distributed to 443 college students from August to September of 2000. After eliminating incomplete questionnaires, 396 were analyzed. As results of factor analysis, 7 desired image factors were determined for male and female, respectively. On the basis of these results, major perception differences were identified according to sex variable. Differently-perceived image words were as fellows: For intellectual image, male relates it with sporty while female relates it with graceful; for masculine image, male relates it with mature while female relates it with sporty; and for feminine image, male relates it with sexy and graceful while female relates it modest, pure, and cute. Multidimensional scaling was employed to determine the perception dimension of desired image. Two dimensions were accepted to interpret the results for both sex, respectively. 'Feminine-masculine' and 'conspicuous-plain' were criteria for male students, while 'unnatural-natural' and 'feminine-masculine' were criteria for female students.

• Archives of Plastic Surgery
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• v.39 no.2
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• pp.162-165
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• 2012

The synchondrosis between the sixth and seventh costal cartilage is usually used for the base frame in autogenous ear reconstruction. If the synchondrosis is loose, a variety of modifications can be devised. This report introduces new methods for these problems. In cases of incomplete synchondrosis, only the surface of the base block margin was smoothly tapered without carving for the removal of the conchal deepening. The secure fixation of the two segments (helix and antihelix) to the base block using fine wire sutures gave stability to the unstable basal frame. After confirming that all the segments were assembled in one stable piece, the remaining conchal deepening of the basal framework was removed, and the outer lower portion of the basal cartilage was trimmed along its whole length. A total of 10 consecutive patients with microtia, ranging from 8 to 13 years old, were treated from 2008 to 2009. The follow-up period was 6 months to 2 years. Despite incomplete synchondrosis, the stable frameworks were constructed using the authors' method and aesthetically acceptable results were achieved. The proposed method can provide an easy way to make a stable cartilage framework regardless of the variable conditions of synchondrosis.

• Journal of the Korea Convergence Society
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• v.12 no.8
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• pp.39-45
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• 2021

This paper discusses how to handle incomplete data including missing values. Optimally processing the missing value means obtaining an estimate that is the closest to the original value from the information contained in the training data, and replacing the missing value with this value. The way to achieve this is to use a decision tree that is completed in the process of classifying information by the classifier. In other words, this decision tree is obtained in the process of learning by inputting only complete information that does not include loss values among all training data into the C4.5 classifier. The nodes of this decision tree have classification variable information, and the higher node closer to the root contains more information, and the leaf node forms a classification region through a path from the root. In addition, the average of classified data events is recorded in each region. Events including the missing value are input to this decision tree, and the region closest to the event is searched through a traversal process according to the information of each node. The average value recorded in this area is regarded as an estimate of the missing value, and the compensation process is completed.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.386-391
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• 2001

This paper presents a new two-point approximation method based on the exponential intervening variable. To avoid the lack of definition of the conventional exponential intervening variables due to zero- or negative-valued design variables the shifting level into each exponential intervening variable is introduced. Then a new quadratic approximation, whose Hessian matrix has only diagonal elements of different values, is proposed in terms of these intervening variables. These diagonal elements are computed in a closed form, which correct the typical error in the approximate gradient of the TANA series due to the lack of definition of exponential type intervening variables and their incomplete second-order terms. Also, a correction coefficient is multiplied to the pre-determined quadratic term to match the value of approximate function with that of the original function at the previous point. Finally, the authors developed a sequential approximate optimizer, solved several typical design problems used in the literature and compared these optimization results with those of TANA-3. These comparisons show that the proposed method gives more efficient and reliable results than TANA-3.