197 research outputs found
Secrecy outage analysis for Alamouti space-time block coded non-orthogonal multiple access
This letter proposed a novel transmission technique for physical layer security by applying the Alamouti Space-Time Block Coded Non-orthogonal Multiple Access (STBC-NOMA) scheme. The secure outage performance under both perfect successive interference cancellation (pSIC) and imperfect successive interference cancellation (ipSIC) are investigated. In particular, novel exact and asymptotic expressions of secrecy outage probability are derived. Numerical and theoretical results are presented to corroborate the derived expressions and to demonstrate the superiority of STBC-NOMA and its ability to enhance the secrecy outage performance compared to conventional NOMA
Decision Model for COTS Component Procurement Based on Case-based Retrieval and Goal Programming
Compared with traditional information system development methodology, COTS-based information system has the following advantages: Avoid expensive development and maintenance; frequent upgrades often anticipate organization’s need; rich functionality; mature technologies; tracks technology trends, etc. However, how to select appropriate COTS components is a complex problem. For improving the accuracy of decision-making in COTS component procurement, a two-period model is put forward. In the first period, the procurement requirement of each COTS component is compared with a COTS component case base by case-based retrieval (CBR) and the initial candidates are selected. In the second period, a (0-1) integer goal programming model is created to optimize cost and time of the whole COTS-based system, and help decision makers to decide the final candidates. Case shows that the two-period method declines the complexity of computation and increases the rationality of decisio
Simultaneous Measurement of Temperature and Pressure with Cascaded Extrinsic Fabry-Perot Interferometer and Intrinsic Fabry-Perot Interferometer Sensors
This paper presents an approach for simultaneous measurement of temperature and pressure using miniaturized fiber inline sensors. The approach utilizes the cascaded optical fiber inline intrinsic Fabry-Perot interferometer and extrinsic Fabry-Perot interferometer as temperature and pressure sensing elements, respectively. A CO2 laser was used to create a loss between them to balance their reflection power levels. The multiplexed signals were demodulated using a Fast Fourier transform-based wavelength tracking method. Experimental results showed that the sensing system could measure temperature and pressure unambiguously in a pressure range of 0 to 6.895 x 105 Pa and a temperature range from 20°C to 700°C
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