4,634 research outputs found
Development of a structured approach for decomposition of complex systems on a functional basis
YesThe purpose of this paper is to present the System State Flow Diagram (SSFD) as a structured and coherent methodology to decompose a complex system on a solution-independent functional basis. The paper starts by reviewing common function modelling frameworks in literature and discusses practical requirements of the SSFD in the context of the current literature and current approaches in industry. The proposed methodology is illustrated through the analysis of a case study: design analysis of a generic Bread Toasting System (BTS)
Research on the efficiency and performance of camera traps and dome system for wild goat inventory
This study, carried out in 2009-2010, aims to use imaging technology for wild goat inventory in the study area, because direct counts done by means of labor intensive techniques give high error rates. Camera traps and dome systems are used to investigate the replacement of direct counts done by authorized institutions, using manpower in vast and rough terrains for Capra aegagrus. In a total area of 555 hectares, of which 50 were for establishing dome and camera traps, the monitoring system recorded images in predefined hours (07.00 to 09.00; 17.00 to 19.00). These periods also coincide with the selected hours for point counts during periodical inventories for wild goat by the relevant official department. The group size of wild goat was determined as 18. 1, which was captured by the dome camera or camera traps. While dome camera system was not able to monitor the entire group, significant information on the number of the wild goats was via camera system. As a result, if used together, camera traps and dome camera system could contribute effectively to wildlife inventory work, providing 70% of the need for the inventory. The study has shown that it is possible to transfer load of manmade inventory to technology and to achieve much more economical inventories by eliminating the risks and disadvantages caused by human factorKey words: Wild goat (Capra aegagrus), inventory, direct counts, camera traps, dome system
Towards an Integrated Approach to Verification and Model-Based Testing in System Engineering
yesEngineering design in general and system design of embedded software have a direct impact on the final engineering product and the software implementation, respectively. Guaranteeing that the models utilised meet the specified requirements is beneficial in detecting misbehaviour and software flaws. This requires an integrated approach, combining verification and model-based testing methodology and notations and methods from system engineering and software engineering. In this paper, we propose a model-based approach integrating various notations utilised in the functional design of complex systems with formal verification and testing. We illustrate our approach on the cruise control system of an e-Bike case study
Comparison of PI Controllers Designed for the Delay Model of TCP/AQM Networks
Cataloged from PDF version of article.One of the major problems of communication networks is congestion. In order to address this problem in TCP/IP networks, Active Queue Management (AQM) scheme is recommended. AQM aims to minimize the congestion by regulating the average queue size at the routers. To improve upon AQM, recently, several feedback control approaches were proposed. Among these approaches, PI controllers are gaining attention because of their simplicity and ease of implementation. In this paper, by utilizing the fluid-flow model of TCP networks, we study the PI controllers designed for TCP/AQM. We compare these controllers by first analyzing their robustness and fragility. Then, we implement these controllers in ns-2 platform and conduct simulation experiments to compare their performances in terms of queue length. Taken together, our results provide a guideline for choosing a PI controller for AQM given specific performance requirements. (C) 2013 Elsevier B.V. All rights reserved
Application of Deep Neural Network to Predict the High-Cycle Fatigue Life of AISI 1045 Steel Coated by Industrial Coatings
In this study, deep learning approach was utilized for fatigue behavior prediction, analysis, and optimization of the coated AISI 1045 mild carbon steel with galvanization, hardened chromium, and nickel materials with different thicknesses of 13 and 19 mu m were used for coatings and afterward fatigue behavior of related specimens were achieved via rotating bending fatigue test. Experimental results revealed fatigue life improvement up to 60% after applying galvanization coat on untreated material. Obtained experimental data were used for developing a Deep Neural Network (DNN) modelling and accuracy of more than 99%.was achieved. Predicted results have a fine agreement with experiments. In addition, parametric analysis was carried out for optimization which indicated that coating thickness of 10-15 mu m had the highest effects on fatigue life improvement
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Functional Modelling of Systems with Multiple Operation Modes: Case Study on an Active Spoiler System
YesThis article presents the application of the Enhanced Sequence Diagram (ESD) for the analysis of the functionality of a system with shape-changing aspects in the context of its multiple operational
modes, considering an active rear spoiler as a case study. The article provides new insights on the ESD support for model-based capture and articulation of functional requirements across multiple operation modes of the same system, with appropriate detail on attributes and metrics, and the alignment of these attributes and metrics in line with the concept of time through scope lines. The article also provides a comprehensive argument and discussion, exemplified based on the case study, for the support that the ESD provides for early systems functional and architecture analysis, within the context of a broader model-based Failure Mode Analysis methodology
Dual functionality of conjugated polymer nanoparticles as an anticancer drug carrier and a fluorescent probe for cell imaging
Cataloged from PDF version of article.Multifunctional nanoparticles based on a green emitting, hydrophobic conjugated polymer, poly[(9,9-bis{propeny}fluorenyl-2,7-diyl)-co-(1,4- benzo-{2,1,3}-thiodiazole)] (PPFBT), that acts both as a fluorescent reporter and a matrix to accommodate an anti-cancer compound, camptothecin (CPT), were prepared, characterized and their potential as a fluorescent probe for cell imaging and as a drug delivery vehicle were evaluated via in vitro cell assays. The cell viability of human hepatocellular carcinoma cell line (Huh7) was investigated in the absence and presence of CPT with sulforhodamine B (SRB) and real-time cell electronic sensing (RT-CES) cytotoxicity assays
The electron diffusion coefficient tensor by using the real geometry of the Earth’s magnetic field in ionospheric plasma
In this study, the electron diffusion coefficients are calculated as depending on latitude, local time and seasonal in the ionospheric plasma by using the real geometry of Earth’s magnetic field for north hemisphere. It is observed that if the earth’s magnetic field is taken into account, the medium is anisotropic in ionospheric plasma. Due to this, the electron diffusion coefficients have tensorial form in the ionospheric plasma. As general, there is a harmony between change of the electron diffusion coefficient and the change of the electron density with local time in the ionospheric plasmaBu çalışmada, dünyanın gerçek manyetik alan geometrisi kullanılarak kuzey yarım küre için iyonosferik plazmada elektron difüzyon katsayıları yüksekliğe, yerel zamana ve mevsime bağlı olarak hesaplandı. Eğer dünyanın manyetik alanı hesaba katılırsa iyonosferik plazmada ortam anizotropik olur. Bundan dolayı iyonosferik plazmada elektron difüzyon katsayısı tensörel bir forma sahiptir. Genel olarak, elektron difüzyon katsayısının yerel zamanla değişimi ve elektron yoğunluğun yerel zamanla değişimi arasında bir uyum vardı
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The Use of Function Modelling Methods in Industry: Insights from a Large Scale Study with an Automotive OEM
YesThis paper presents an evaluation study for the System State Flow Diagram function modeling framework
based on a large-scale study with an automotive OEM. Technical reports are used to evaluate the usage of
the framework within the organization. The paper also introduces a list of the type of problems that
engineers are interested in in practical function modelling. The findings suggest that there is a widespread
uptake of the framework across the organization and it supports the usage of relevant key engineering tools
within the context of a broader model-based Failure Mode Analysis methodology
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