Epizootic Hemorrhagic Disease in Cattle, Western Turkey

In 2007, an outbreak of epizootic hemorrhagic disease (EHD) occurred in Turkey. On the basis of clinical investigation, 41 cattle were suspected to have EHD. Reverse transcription–PCR and sequence analyses indicated that the virus belonged to EHD virus serotype 6, thus confirming EHD virus infection of cattle in Turkey

Small response surface designs for metamodel estimation

WOS: 000180099100017The primary objective of this study is to provide the novice researchers in simulation metamodeling with guidance on how to use small designs for metamodel estimation especially when cost effectiveness is a concern. This study was carried out in three phases: First, a group of second-order small designs were evaluated with respect to various criteria. Next, the metamodel of a time-shared computer system was estimated using these designs. Finally, the predictive capabilities of these small designs in giving the best metamodel fit were investigated, and also, the performance of small designs was compared with two large size standard designs. Results indicate that the metamodel estimated using the hybrid design has the best predictive capability among the small designs, and its performance competes with that of the standard designs studied. (C) 2002 Published by Elsevier Science B.V

Dealing with the least squares regression assumptions in simulation metamodeling

WOS: 000090012300007The aim of this study is twofold. The first is to estimate a metamodel for a time-shared computer system using a sequential design procedure, The second is to deal extensively with the least squares regression assumptions during the metamodel development. In the first stage of the experimentation, a first-order metamodel is estimated using the two-level factorial design. Later, the design is augmented with replicated center points for curvature check. Upon the detection of the significance of the curvature, a central composite design is used for fitting a second-order metamodel, which explains the relation between the levels of the input factors, and the response of interest. In both stages, various diagnostic statistical tests such as normality test, variance homogeneity test, lack-of-fit test and etc, are carried out to make sure that the method of least squares is properly and efficiently applied. (C) 2000 Elsevier Science Ltd. All rights reserved

Second-order experimental designs for simulation metamodeling

WOS: 000181725900001The main purpose of this study is to compare the performance of a group of second-order designs such as Box-Behnken, face-center cube, three-level factorial, central composite, minimum bias, and minimum variance plus bias for estimating a quadratic metamodel. A time-shared computer system is used to demonstrate the ability of the designs in providing good fit of the metamodel to the simulation response. First, for various numbers of center runs, these designs are compared with respect to their efficiency, rotatability, orthogonality, robustness, bias, and prediction variance. Next, second-order metamodels are fit to the data collected using these designs. Metamodel fit is investigated using criteria such as average absolute error, PRESS, and the C-p statistic. Results indicate that the minimum variance plus bias design is the most promising design to estimate a metamodel for the case studied

A metamodeling methodology involving both qualitative and quantitative input factors

This paper suggests a methodology for developing a simulation metamodel involving both quantitative and qualitative factors. The methodology mainly deals with various strategic issues involved in metamodel estimation, analysis, comparison, and validation. To illustrate how to apply the methodology, a regression metamodel is developed for a client-server computer system. In particular, we studied how the response time is affected by the quantum interval, the buffer size. and the total number of terminals when different queuing disciplines are employed in the operation of the round-robin queue with a limited buffer. The results of the study indicate that the relationship between the response time and the quantitative factors cannot be adequately described by a single metamodel for all queuing disciplines

A comparative study on the actual and estimated seismic response of Kiralkizi Dam in Turkey

Kiralkizi Dam, a 120 in high earthfill dam located in Diyarbakir city, Turkey, was shaken by a moment magnitude, M-w = 4.6 earthquake at an epicentral distance of 8 km, on December 24, 2000, at 13:31 local time. The seismic response of the dam was assessed by using spectral ratios between (i) available crest and foundation records (C/F), (ii) horizontal and vertical components of the recorded motions (H/V), (iii) by performing 2 dimensional finite difference-based seismic response analyses (Flac-2D), and (iv) 1D elastic shear beam solutions. First mode of vibration of the dam in the transverse direction by all four methods were estimated in the range of 0.55 to 0.62 second. Similar close agreement was not observed in higher modal periods estimated by H/V technique as compared to the predictions by C/F, Flac-2D, shear beam analysis techniques. Thus, H/V technique was concluded to be useful for the estimation of the fundamental resonance frequency of a soil structure, but not for its higher harmonics as consistent with available limited literature. In the longitudinal direction, natural period of the dam was estimated as 0.28 and 0.82 second by H/V and C/F techniques, respectively. Such disagreement was explained by (i) differences in the definitions of the estimated periods, (ii) internal impedance contrast of the dam, (iii) contributions of 3D valley effects. Single seismometer record obtained from crest level was found to be inadequate for reliably assessing the response of a dam in the longitudinal direction, and it is recommended to install multiple seismometers both within dambody and the abutments. Last but not least, the results of these analyses were further compared by available accelograms recorded at three earthfill and rockfill dams from Japan. In general, it was concluded that the seismic response of Kiralkizi Dam is comparable and within the prediction ranges of available analyses methods and is consistent with the expected response of a dam this height

Dynamic simulation metamodeling using MARS: A case of radar simulation

Dynamic system simulations require relating the inputs to the multivariate output which can be a function of time space coordinates. In this work, we propose a methodology for the metamodeling of dynamic simulation models via Multivariate Adaptive Regression Splines (MARS). To handle incomplete output processes, where the simulation model does not produce an output in some steps due to missing inputs, we have devised a two-stage metamodeling scheme. The methodology is demonstrated on a dynamic radar simulation model. The prediction performance of the resulting metamodel is tested with four different sampling techniques (i.e., designs) and 16 sample sizes. We also investigate the effect of alternative coordinate system representations on the metamodeling performance. The results suggest that MARS is an effective method for metamodeling dynamic simulations, particularly, when expert judgment is not readily available. Results also show that there are interactions between the coordinate systems and sampling techniques, and some design-representation-size combinations are very promising in the metamodeling of radar simulations. (C) 2016 International Association for Mathematics and Computers in Simulation (IMACS). Published by Elsevier B.V. All rights reserved