Link-time optimization techniques for eliminating conditional branch redundancies

Author(s):  
M. Fernandez ◽  
R. Espasa
Author(s):  
Zhongyou Wu ◽  
Yaoyu Li

Real-time optimization of wind farm energy capture for below rated wind speed is critical for reducing the levelized cost of energy (LCOE). Performance of model based control and optimization techniques can be significantly limited by the difficulty in obtaining accurate turbine and farm models in field operation, as well as the prohibitive cost for accurate wind measurements. The Nested-Loop Extremum Seeking Control (NLESC), recently proposed as a model free method has demonstrated its great potential in wind farm energy capture optimization. However, a major limitation of previous work is the slow convergence, for which a primary cause is the low dither frequencies used by upwind turbines, primarily due to wake propagation delay through the turbine array. In this study, NLESC is enhanced with the predictor based delay compensation proposed by Oliveira and Krstic [1], which allows the use of higher dither frequencies for upwind turbines. The convergence speed can thus be improved, increasing the energy capture consequently. Simulation study is performed for a cascaded three-turbine array using the SimWindFarm platform. Simulation results show the improved energy capture of the wind turbine array under smooth and turbulent wind conditions, even up to 10% turbulence intensity. The impact of the proposed optimization methods on the fatigue loads of wind turbine structures is also evaluated.


Repositor ◽  
2020 ◽  
Vol 2 (11) ◽  
pp. 1456
Author(s):  
Akhmad Yusuf F ◽  
Ilyas Nuryasin ◽  
Zamah Sari

AbstrakSitus web merupakan sekumpulan dokumen Hypertext Markup Language (HTML) statis yang dibangun untuk memudahkan setiap orang berbagi informasi, selama terhubung ke dalam jaringan internet. Salah satu bagian dari sistem sebuah situs web adalah web template. Web template adalah komponen dasar dari sistem web template berguna untuk memudahkan pengembang web merancang ulang sebuah halaman web. Salah satu yang mempengaruhi kinerja halaman web yaitu loading time, dimana loading time adalah waktu yang dibutuhkan oleh browser agar dapat menampilkan halaman web secara menyeluruh oleh pengguna ketika pengguna melakukan request, selain itu loading time merupakan salah satu bagian penting dari optimasi situs web. Optimasi merupakan suatu proses dimana memodifikasi atau merubah sesuatu yang telah ada agar efektifitasnya meningkat. Dalam sebuah situs web, terdapat beberapa konsep dalam optimasi, yaitu First Paint, Time To Interactivity (TTI), First Meaningful Paint (FMP) dan Long Task. Berdasarkan penelitian-penelitian yang sudah ada, diketahui bahwa optimasi loading time web dapat dilakukan dari sisi front-end. Oleh karena itu pada penelitian ini melakukan teknik optimasi dengan menggunakan critical rendering path, above the fold, priority resource, bundle and minify, gzip, dan splitting code. Hasil dari peforma web berdasarkan metriks first meaningful paint (FMP), first contetful paint (FCP), dan time to interactivity (TTI) mengalami peningkatan rata-rata kecepatan (perosentase) yaitu FMP sebesar 73%, FCP sebesar 60%, TTI sebesar 50%, dan loading time sebesar 29%. Selanjutnya, pada resource file rata-rata ukuran file menurun sebesar 59% dan jumlah request file menurun sebesar 21%.AbstractWebsite is a collection of HTML documents that are built to make it easy for everyone to share information, as long as they are connected to the internet. One part of a website system is a web template. Web templates are the basic components of a web template system useful for making it easy for web developers to redesign a web page. One that affects the performance of web pages is loading time, where loading time is the time needed by the browser to be able to display the web page as a whole by the user when the user makes a request, besides that loading time is one important part of website optimization. Optimization is a process where modifying or changing something that already exists in order to increase its effectiveness. In a website, there are several concepts in optimization, namely First Paint, Time To Interactivity, and First Meaningful Paint Based on existing research, it is known that web loading time optimization can be done from the front-end side. Therefore, in this study, optimization techniques using critical rendering path, above the fold, priority resources, bundle and minify, gzip, and splitting code. The implementation of matrics first meaningful paint (FMP), first contetful paint (FCP), dan time to interactivity (TTI) make increase average of speed FMP as 73%, FCP as 60%, TTI as 50%, and loading time as 29%. And then average of resource file decrease as 59% and total file of request decrease as 21%.  


2020 ◽  
Vol 14 (4) ◽  
pp. 7446-7468
Author(s):  
Manish Sharma ◽  
Beena D. Baloni

In a turbofan engine, the air is brought from the low to the high-pressure compressor through an intermediate compressor duct. Weight and design space limitations impel to its design as an S-shaped. Despite it, the intermediate duct has to guide the flow carefully to the high-pressure compressor without disturbances and flow separations hence, flow analysis within the duct has been attractive to the researchers ever since its inception. Consequently, a number of researchers and experimentalists from the aerospace industry could not keep themselves away from this research. Further demand for increasing by-pass ratio will change the shape and weight of the duct that uplift encourages them to continue research in this field. Innumerable studies related to S-shaped duct have proven that its performance depends on many factors like curvature, upstream compressor’s vortices, swirl, insertion of struts, geometrical aspects, Mach number and many more. The application of flow control devices, wall shape optimization techniques, and integrated concepts lead a better system performance and shorten the duct length.  This review paper is an endeavor to encapsulate all the above aspects and finally, it can be concluded that the intermediate duct is a key component to keep the overall weight and specific fuel consumption low. The shape and curvature of the duct significantly affect the pressure distortion. The wall static pressure distribution along the inner wall significantly higher than that of the outer wall. Duct pressure loss enhances with the aggressive design of duct, incursion of struts, thick inlet boundary layer and higher swirl at the inlet. Thus, one should focus on research areas for better aerodynamic effects of the above parameters which give duct design with optimum pressure loss and non-uniformity within the duct.


2011 ◽  
Vol 39 (4) ◽  
pp. 223-244 ◽  
Author(s):  
Y. Nakajima

Abstract The tire technology related with the computational mechanics is reviewed from the standpoint of yesterday, today, and tomorrow. Yesterday: A finite element method was developed in the 1950s as a tool of computational mechanics. In the tire manufacturers, finite element analysis (FEA) was started applying to a tire analysis in the beginning of 1970s and this was much earlier than the vehicle industry, electric industry, and others. The main reason was that construction and configurations of a tire were so complicated that analytical approach could not solve many problems related with tire mechanics. Since commercial software was not so popular in 1970s, in-house axisymmetric codes were developed for three kinds of application such as stress/strain, heat conduction, and modal analysis. Since FEA could make the stress/strain visible in a tire, the application area was mainly tire durability. Today: combining FEA with optimization techniques, the tire design procedure is drastically changed in side wall shape, tire crown shape, pitch variation, tire pattern, etc. So the computational mechanics becomes an indispensable tool for tire industry. Furthermore, an insight to improve tire performance is obtained from the optimized solution and the new technologies were created from the insight. Then, FEA is applied to various areas such as hydroplaning and snow traction based on the formulation of fluid–tire interaction. Since the computational mechanics enables us to see what we could not see, new tire patterns were developed by seeing the streamline in tire contact area and shear stress in snow in traction.Tomorrow: The computational mechanics will be applied in multidisciplinary areas and nano-scale areas to create new technologies. The environmental subjects will be more important such as rolling resistance, noise and wear.


Sign in / Sign up

Export Citation Format

Share Document