143 research outputs found

    Numerical/Experimental Studies on Performance at Low Engine Speeds:A Case study Downsized Iranian National Engine (EF7)

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    Engine downsizing is a trusted method to reduce fuel consumption and pollution emitted from internal combustion engines. In this method, engine displacement volume is reduced while maintaining the same power/torque characteristics. However, there still exist several limitations to utilize this technology. In this paper, the naturally aspirated type of Iran national engine (EF7-NA) is investigated for a possible downsized version. A one-dimensional engine model equipped with a zero-dimensional two-zone combustion sub-model was developed and validated via experimental results for both natural aspirated and turbocharged engine types. Then experimental and numerical studies were carried out for the primary concept, deactivation of one cylinder besides using a turbocharger. To overcome the concept shortages, especially in lower ranges of engine speed, numerical studies were extended. Deployment of several turbochargers with different performance maps and different valve timing via a dual CVVT system were investigated. The results showed that there is a feasible method for EF7 engine downsizing via a 3-cylinder type equipped with a modified turbocharger and valve timing. The maximum difference between base-engine and downsized version torque is about 7% in low engine speeds

    RTLola Cleared for Take-Off: Monitoring Autonomous Aircraft

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    The autonomous control of unmanned aircraft is a highly safety-critical domain with great economic potential in a wide range of application areas, including logistics, agriculture, civil engineering, and disaster recovery. We report on the development of a dynamic monitoring framework for the DLR ARTIS (Autonomous Rotorcraft Testbed for Intelligent Systems) family of unmanned aircraft based on the formal specification language RTLola. RTLola is a stream-based specification language for real-time properties. An RTLola specification of hazardous situations and system failures is statically analyzed in terms of consistency and resource usage and then automatically translated into an FPGA-based monitor. Our approach leads to highly efficient, parallelized monitors with formal guarantees on the noninterference of the monitor with the normal operation of the autonomous system

    From Object-Process Diagrams to a Natural Object-Process Language

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    High-levelexpression of functional recombinant human coagulation factor VII in insect cells

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    Abstract: Recombinant coagulation factor VII (FVII) is used as a potential therapeutic intervention in hemophilia patients who produce antibodies against the coagulation factors. Mammalian cell lines provide low levels of expression, however, the Spodoptera frugiperda Sf9 cell line and baculovirus expression system are powerful systems for high-level expression of recombinant proteins, but due to the lack of endogenous vitamin K-dependent carboxylase, expression of functional FVII using this system is impossible. In the present study, we report a simple but versatile method to overcome the defect for high-level expression of the functional recombinant coagulation FVII in Sf9 cells. This method involves simultaneous expression of both human γ-carboxylase (hGC) and human FVII genes in the host. It may be possible to express other vitamin K-dependent coagulation factors using this method in the future. Keywords: Baculovirus; γ-carboxylase; Coagulation FVII; Factor VII; Insect cel

    MAC and baseband processors for RF-MIMO WLAN

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    The article describes hardware solutions for the IEEE 802.11 medium access control (MAC) layer and IEEE 802.11a digital baseband in an RF-MIMO WLAN transceiver that performs the signal combining in the analogue domain. Architecture and implementation details of the MAC processor including a hardware accelerator and a 16-bit MACphysical layer (PHY) interface are presented. The proposed hardware solution is tested and verified using a PHY link emulator. Architecture, design, implementation, and test of a reconfigurable digital baseband processor are described too. Description includes the baseband algorithms (the main blocks being MIMO channel estimation and Tx-Rx analogue beamforming), their FPGA-based implementation, baseband printed-circuit-board, and real-time test

    Mobile Consumer Behavior in Fashion m-Retail: An Eye Tracking Study to Understand Gender Differences

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    © 2020 ACM. With exponential adoption of mobile devices, consumers increasingly use them for shopping. There is a need to understand the gender differences in mobile consumer behavior. This study used mobile eye tracking technology and mixed-method approach to analyze and compare how male and female mobile fashion consumers browse and shop on smartphones. Mobile eye tracking glasses recorded fashion consumers' shopping experiences using smartphones for browsing and shopping on the actual fashion retailer's website. 14 participants successfully completed this study, half of them were males and half females. Two different data analysis approaches were employed, namely a novel framework of the shopping journey, and semantic gaze mapping with 31 Areas of Interest (AOI) representing the elements of the shopping journey. The results showed that male and female users exhibited significantly different behavior patterns, which have implications for mobile website design and fashion m-retail. The shopping journey map framework proves useful for further application in market research
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