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Comprehensive preliminary sizing/resizing method for a fixed wing – VTOL electric UAV
Tyan, Maxim,Nguyen, Nhu Van,Kim, Sangho,Lee, Jae-Woo Elsevier 2017 AEROSPACE SCIENCE AND TECHNOLOGY Vol.71 No.-
<P><B>Abstract</B></P> <P>A Fixed Wing (FW) aircraft with Vertical Takeoff and Landing (VTOL) is a new type of aircraft that inherits the hovering, VTOL, and maneuvering properties of multicopters and the power-efficient cruising of an FW aircraft. This paper presents a comprehensive method for FW-VTOL electric UAV sizing and resizing. The method uses newly developed integrated analysis that combines the VTOL propulsion sizing method with modified FW aircraft sizing theories. Performance requirements are specified as a set of functional relations. Several new empirical equations are derived using available data. The required battery capacity and total mass are determined from mission analysis that includes both VTOL and FW mission segments. The design is iteratively resized when the actual components of the propulsion system are selected. A case study of a 3.5-kg FW-VTOL electric UAV is presented in this research. The results of sizing and resizing are compared to parameters of the actual aircraft manufactured. Prediction of most parameters stays within a 10% error threshold.</P>
Tyan, M.,Nguyen, N. V.,Kim, S.,Lee, J.-W. American Institute of Aeronautics and Astronautics 2017 Journal of aircraft Vol. No.
<P>Aircraft conceptual design traditionally uses simplified analysis and optimization methods to generate the basic configuration of the aircraft. Analysis methods cannot fully represent the real physical phenomena, and hence the optimum solution may fail to satisfy the constraints when more sophisticated analysis is applied. This research proposes the use of a database to estimate the prediction errors associated with a particular analysis method. Newly proposed adaptive piecewise-linear fuzzy membership functions accurately represent the intervals of prediction errors to compensate for the discrepancies caused by analysis. A possibility-based design optimization framework is developed to solve nonprobabilistic design problems with uncertainties represented by the adaptive piecewise-linear fuzzy membership intervals. A two-seater light aircraft design problem has been solved to demonstrate the proposed method. The adaptive piecewise-linear fuzzy membership fu\nctions for six major analysis modules of in-house software were constructed using information about 15 aircraft stored in the database. Estimated errors of the analysis stay within 10% range. The adaptive piecewise-linear fuzzy membership function for selected parameters stores 39% more samples on average than the triangular functions that are traditionally used for possibility-based design optimization. The results of the design problem show that the objective function is improved by 3.4% with uncertain intervals covering 100% of database samples and by 46.1% with 12.3% database coverage.</P>
Nguyen Tyan Ahn,Jin Chul Shin,Byun-Woo Lee 韓國作物學會 2005 한국작물학회지 Vol.50 No.4
Rice yield and protein content have been shown to be highly variable across paddy fields. In order to characterize this spatial variability of rice within a field, two-year experiments were conducted in 2002 and 2003 in a large-scale rice field of 6,600m2 In year 2004, an experiment was conducted to know if variable rate treatment (VRT) of N fertilizer, that was prescribed for site-specific management at panicle initiation stage, could reduce spatial variation in yield and protein content of rice while increasing yield compared to conventional uniform N topdressing (UN, 33kg N/ha at PIS) method. VRT nitrogen prescription for each grid was calculated based on the nitrogen (N) uptake (from panicle initiation to harvest) required for target rice protein content of 6.8~% , natural soil N supply, and recovery of top-dressed N fertilizer. The required N uptake for target rice protein content was calculated from the equations to predict rice yield and protein content from plant growth parameters at panicle initiation stage (PIS) and N uptake from PIS to harvest. This model· equations were developed from the data obtained from the previous two-year experiments. The plant growth parameters for the calculation of the required N were predicted non-destructively by canopy reflectance measurement. Soil N supply for each grid was obtained from the experiment of year 2003, and N recovery was assumed to be 60~% according to the previous reports. The prescribed VRT N ranged from 0 to 110kg N/ha with an average of 57kg/ha that was higher than 33 kg/ha of UN. The results showed that VRT application successfully worked not only to reduce spatial variability of rice yield and protein content but also to increase rough rice yield by 960kg/ha. The coefficient of variation (CV) for rice yield and protein content was reduced significantly to 8.1~% and 7.1~% in VRT from 14.6~% and 13.0~% in UN, respectively. And also the average protein content of milled rice in VRT showed very similar value of target protein content of 6.8~% . In conclusion the procedure used in this paper was believed to be reliable and promising method for reducing within-field spatial variability of rice yield and protein content. However, inexpensive, reliable, and fast estimation methods of natural N supply and plant growth and nutrition status should be prepared before this method could be practically used for site-specific crop management in large-scale rice field.
Do institutional designs matter for planning review? A garbage-can simulation approach
Feng-Tyan Lin,Shih-Kung Lai 서울시립대학교 도시과학연구원 2022 도시과학국제저널 Vol.26 No.3
The fact that institutional design coordinates decisions are not a new idea, but the study of its effectiveness under different settings is still unrevealed. In this paper, inspired by the garbage-can model, we conduct a set of computer simulations of collective decision making based on urban land use planning and design review process. The simulation results show that institutional designs matter in affecting organizational performance, and that different distributions of case intricacies result in different outcomes of the collective decision making for planning review.
Integrated Analysis Program Development for Light Aircraft Preliminary Design Stage
Maxim Tyan,Daniel Neufeld,Jae-Woo Lee,Sangho Kim 한국항공우주학회 2013 한국항공우주학회 학술발표회 논문집 Vol.2013 No.4
A comprehensive program development using a multi-disciplinary approach for propeller driven aircraft analysis, design and optimization is presented in this paper. The program consists of a worksheet format database with a data processing module along with modules for aerodynamic, propulsion, mission, weight and geometry analysis, and 3D geometry display. The program was written using object oriented programming to enhance exibility and extensibility compared to functional programming approach. Additional analysis modules and design optimization extensions can be written and integrated easily. The developed program source code is being continuously optimized to reduce computational time and improve effciency. Most of the methods used in current program were used for conceptual and preliminary design of the KLA-100, a new VLA category aircraft. The accuracy of the analysis methods was validated using experimental and published data.