著者

金崎 雅博 千葉 一永 北川 幸樹 嶋田 徹

出版者

進化計算学会

雑誌

進化計算学会論文誌 (ISSN:21857385)

巻号頁・発行日

vol.6, no.3, pp.137-145, 2015 (Released:2015-12-18)

参考文献数

19

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With the multi-combustion technology, the combustion in a hybrid rocket engine (HRE) can be temporarily stopped via oxidizer throttling. In this paper, two types of HREs, one with multi-combustion technology and the other without, are compared to investigate the effects of multi-combustion on the flight performance of launch vehicles (LVs). Non-dominated Sorting Genetic Algorithm-II (NSGA-II) which was a multi-objective evolutionary algorithm (MOEA) was applied to solve the design problems using real-number coding and the Pareto ranking method. To investigate the effects of the multi-combustion on flight performance of LV with HRE, three design problems were considered. The first case was the maximization of the flight altitude and the minimization of the gross weight. The second case was the minimization of the maximum acceleration and the minimization of the gross weight. The final case was the maximization of the flight downrange and the minimization of the gross weight. Many non-dominated solutions were obtained by NSGA-II, and a trade-off was observed between the two objective functions in each case. MOEA results were visualized using a parallel coordinate plot. According to the exploration result, it was found that the multi-combustion of HRE was effective to reduce the maximum acceleration. Such ability could be expected to reduce the shock load to payloads carried by the LV with HRE.

著者

千葉 一永 金崎 雅博

出版者

進化計算学会

雑誌

進化計算学会論文誌 (ISSN:21857385)

巻号頁・発行日

vol.4, no.1, pp.28-37, 2013 (Released:2013-05-17)

参考文献数

22

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Design informatics, which is the efficient design methodology, has three points of view. The first is the efficient exploration in design space using evolutionary-based optimization methods. The second is the structurization and visualization of design space using data mining techniques. The third is the application to practical problems. In the present study, the influence of the difference among the seven pure and hybrid optimization methods for design information has been investigated in order to explain the selection manner of optimization methods for data mining. The practical problem of a single-stage hybrid rocket is picked up as the present design object. A functional analysis of variance and a self-organizing map are employed as data mining techniques in order to acquire the global design information in dasign space. As a result, mining result depends on not the number of generation (i.e. convergence) but the optimization methods (i.e. exploration space). Consequently, the optimization method with diversity performance is the beneficial selection in order to obtain the global design information in design space.

著者

亀井 卓也 伊藤 那知 菅井 慎也 太田 諭志 佐鳥 新 千葉 一永

出版者

一般社団法人 日本航空宇宙学会

雑誌

航空宇宙技術 (ISSN:18840477)

巻号頁・発行日

vol.12, pp.111-117, 2013 (Released:2013-11-28)

参考文献数

16

被引用文献数

1 1

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Precision agriculture has been being implemented in order environmentally friendly and efficiently to product and manage crops. The remote sensing by satellite and aircraft is employed in order to obtain the information regarding the growth of crops. Although the data from satellites can include wide-range image each time, it is insufficient due to the fixed orbital path of satellites. Therefore, fixed-point observations cannot be sufficiently performed. Moreover, the observations on fixed orbital path cannot be always carried out because of cloud. Although aircrafts are used for the interpolation of the insufficient data by satellites, manned aircrafts need high personnel expenses and maintenance costs. Therefore, unmanned aerial vehicle (UAV) is recently employed. The objective of the present study is the development of the system to generate the interpolated image data by normalized difference vegetation index (NDVI) map taken by small-type UAV (sUAV), which is low-priced and simple system to implement precision agriculture. The following three assignments have been concretely performed in the present study; 1) light-weight four-band multispectral camera carried in sUAV will be developed, 2) sUAV is managed and the image data will be taken, and 3) NDVI map will be generated from the image data by sUAV and interpolated image data will also be developed to contribute precision agriculture. Consequently, the lightest four-band multispectral camera in the world has been developed, and also sUAV has been able to be successfully managed and acquired image data could also generates NDVI maps.