http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Model parameter identification of the Hansel-Spitttel flow stress equation by statistical regression
Kyunghoon Lee(이경훈),Woojin Song(송우진) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.2015 No.11
For forming simulation flow stress modeling is imperative in emulating the mechanical behavior of a material of interest. Flow stress models are typically determined by model parameter identification via least squares methods. Instead, this research tackles the same problem of model parameters identification by statistical regression. To determine the parameters of a flow stress model, this research presumes an additive noise model for experimental strain and stress measurements in a log space. Based on a probabilistic formulation, this research draws on the method of maximum likelihood to derive the parameters of a flow stress model. For illustration, we used the Hansel-Spittel flow stress equation with strain and stress measurements of AA1070 aluminum alloys. We found that the fitted Hansel-Spittel flow stress model agrees well with the strain and stress measurements.
Study on Performance Prediction of Electric Propulsion System for Multirotor UAVs
정진석(Jinseok Jeong),변영섭(Youngseop Byun),송우진(Woojin Song),강범수(Beomsoo Kang) Korean Society for Precision Engineering 2016 한국정밀공학회지 Vol.33 No.6
This paper describes a study of performance prediction of an electric propulsion system for multirotor UAVs. The electric propulsion system consists of motors, propellers, batteries and speed controllers, and significantly affects performance characteristics of the platform. The performance of the electric propulsion system for multirotor UAVs was predicted using an analytical model derived from the characteristics of each component, operation experiments and statistical analyses. Ground performance tests and endurance flights were performed to verify the reliability of the proposed performance prediction method. A quadrotor platform was designed to demonstrate the parcel delivery service used in the endurance flight. From the result of verification tests, it was confirmed that the proposed method has a good agreement.