1,057 research outputs found
A B-ISDN-compatible modem/codec
Coded modulation techniques for development of a broadband integrated services digital network (B-ISDN)-compatible modem/codec are investigated. The selected baseband processor system must support transmission of 155.52 Mbit/s of data over an INTELSAT 72-MHz transponder. Performance objectives and fundamental system parameters, including channel symbol rate, code rate, and the modulation scheme are determined. From several candidate codes, a concatenated coding system consisting of a coded octal phase shift keying modulation as the inner code and a high rate Reed-Solomon as the outer code is selected and its bit error rate performance is analyzed by computer simulation. The hardware implementation of the decoder for the selected code is also described
Efficient Optimal Minimum Error Discrimination of Symmetric Quantum States
This paper deals with the quantum optimal discrimination among mixed quantum
states enjoying geometrical uniform symmetry with respect to a reference
density operator . It is well-known that the minimal error probability
is given by the positive operator-valued measure (POVM) obtained as a solution
of a convex optimization problem, namely a set of operators satisfying
geometrical symmetry, with respect to a reference operator , and
maximizing . In this paper, by resolving the dual
problem, we show that the same result is obtained by minimizing the trace of a
semidefinite positive operator commuting with the symmetry operator and
such that . The new formulation gives a deeper insight into the
optimization problem and allows to obtain closed-form analytical solutions, as
shown by a simple but not trivial explanatory example. Besides the theoretical
interest, the result leads to semidefinite programming solutions of reduced
complexity, allowing to extend the numerical performance evaluation to quantum
communication systems modeled in Hilbert spaces of large dimension.Comment: 5 pages, 1 Table, no figure
Ionization Rate, Temperature, and Number Density for Breakdown Waves with a Large Current Behind the Shock Front
A three component, one-dimensional, constant velocity, steady-state fluid model is employed to describe the breakdown waves with a current behind the wave front propagating into a neutral gas subjected to an external electric field. Electron gas partial pressure is much larger than that of the other species and therefore is considered to provide the driving force for the wave. The system of equations includes the equations of conservation of mass, momentum, and energy coupled with Poisson’s equation. Inclusion of current behind the wave front in the system of fluid equations also alters the initial boundary conditions and ionization rate. We are considering an ionization rate which changes from accelerational ionization at the front of the wave to directed velocity ionization in the intermediate stages of the wave to thermal ionization at the end of the wave. Using the modified boundary conditions, the set of electron fluid dynamical equations have been integrated through the dynamical transition region of the wave. The effect of current behind the shock front on the wave profile for electric field, electron velocity, ionization rate, electron number density, and electron temperature will be presented
CANDELS Multi-wavelength Catalogs: Source Identification and Photometry in the CANDELS COSMOS Survey Field
We present a multi-wavelength photometric catalog in the COSMOS field as part of the observations by the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey. The catalog is based on Hubble Space Telescope Wide Field Camera 3 (HST/WFC3) and Advanced Camera for Surveys observations of the COSMOS field (centered at R.A.: 10^h00^m28^s, Decl.:+02^º12^'21^"). The final catalog has 38671 sources with photometric data in 42 bands from UV to the infrared (~ 0.3-8 µm). This includes broadband photometry from HST, CFHT, Subaru, the Visible and Infrared Survey Telescope for Astronomy, and Spitzer Space Telescope in the visible, near-infrared, and infrared bands along with intermediate- and narrowband photometry from Subaru and medium-band data from Mayall NEWFIRM. Source detection was conducted in the WFC3 F160W band (at 1.6 μm) and photometry is generated using the Template FITting algorithm. We further present a catalog of the physical properties of sources as identified in the HST F160W band and measured from the multi-band photometry by fitting the observed spectral energy distributions of sources against templates
Microencapsulation of saffron petal anthocyanins with cress seed gum compared with Arabic gum through freeze drying
In this research, encapsulation efficiency of cress seed gum (CSG) as a native hydrocolloid was compared with Arabic gum (AG) and maltodextrin (dextrose equivalent of 20 (M20), and 7 (M7)) for saffron (Crocus sativus) petal's extract by freeze drying method. Combinations of CSG-M20, AG-M20, and M7-M20 with ratios of 50:50 and M20 alone (100%) were used as wall materials. A mixture of 1:5 (based on dry matter) between core (concentrated anthocyanin extract of saffron petal) and wall materials were freeze dried and stability of encapsulated anthocyanins along with color parameters (a∗, b∗, L∗, C, H° and TCD) of final powders were measured during 10 weeks of storage (at 35 °C as an accelerated method). Total anthocyanins were determined through pH differential method every week. Four prepared formulations of encapsulated powders didn't show any significant differences (P > 0.01) in terms of total anthocyanin content measured immediately after production and after 10 weeks storage. AG-M20 mixture and M20 alone showed the highest and lowest TCD, respectively. The mixture of CSG-M20 in comparison with AG-M20 and M20 had the same protecting effect (P < 0.01) but showed a relatively high TCD (9.33). © 2015 Elsevier Ltd. All rights reserved
Momentum analysis of complex time-periodic flows
Several methods have been proposed to characterize the complex interactions
in turbulent wakes, especially for flows with strong cyclic dynamics. This
paper introduces the concept of Fourier-Averaged Navier-Stokes (FANS) equations
as a framework to obtain direct insights into the dynamics of complex coherent
wake interactions. The method simplifies the interpretations of flow physics by
identifying terms contributing to momentum transport at different timescales.
The method also allows for direct interpretation of non-linear interactions of
the terms in the Navier-Stokes equations. By analysing well-known cases, the
characteristics of FANS are evaluated. Particularly, we focus on physical
interpretation of the terms as they relate to the interactions between modes at
different timescales. Through comparison with established physics and other
methods, FANS is shown to provide insight into the transfer of momentum between
modes by extracting information about the contributing pressure, convective,
and diffusive forces. FANS provides a simply calculated and easily interpreted
set of equations to analyse flow physics by leveraging momentum conservation
principles and Fourier analysis. The method is applicable to flows with complex
cyclic waveforms, including broadband spectral energy distributions.Comment: 28 pages, 23 figures. Submitted to the Journal of Fluid Mechanic
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Photoswitchable Nanoparticles for Triggered Tissue Penetration and Drug Delivery
We report a novel nanoparticulate drug delivery system that undergoes reversible volume change from 150 to 40 nm upon phototriggering with UV light. The volume change of these monodisperse nanoparticles comprising spiropyran, which undergoes reversible photoisomerization, and PEGylated lipid enables repetitive dosing from a single administration and enhances tissue penetration. The photoswitching allows particles to fluoresce and release drugs inside cells when illuminated with UV light. The mechanism of the light-induced size switching and triggered-release is studied. These particles provide spatiotemporal control of drug release and enhanced tissue penetration, useful properties in many disease states including cancer
Zero Energy Building by Multi-Carrier Energy Systems including Hydro, Wind, Solar and Hydrogen
This paper proposes a unified solution to address the energy issues in net zero energy building (ZEB), as a new contribution to earlier studies. The multi carrier energy system including hydro-wind-solar-hydrogen-methane-carbon dioxide-thermal energies is integrated and modeled in ZEB. The electrical sector is supplied by hydro-wind-solar, combined heat and power, and pumped hydro storage. The purpose is to minimize the released CO2 to the atmosphere while all the electrical-thermal load demands are successfully supplied following events and disruptions. The model improves the energy resilience and minimizes the environmental pollutions simultaneously. The results demonstrate that the developed model reduces the CO2 pollution by about 33451 kg per year. The model is a resilient energy system that can handle all failures of components and supply both the thermal and electrical loads following events. The model can efficiently handle 26% increment in the electrical loads and 110% increment in the thermal loads.© 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.fi=vertaisarvioitu|en=peerReviewed
A novel hybrid cybersecurity scheme against false data injection attacks in automated power systems
Multicarrier Microgrid Operation Model Using Stochastic Mixed Integer Linear Programming
The microgrid operation is addressed in this article based on a multicarrier energy hub. Natural gas, electricity, heating, cooling, hydrogen, carbon dioxide, and renewable energies are considered as the energy carriers. The designed microgrid optimizes and utilizes a wide range of resources at the same time including renewables, electrical storage, hybrid storage, heating-cooling storage, electric vehicles (EVs) charging station, power to gas unit, combined cooling-heating-power, and carbon capture-storage. The purpose is to reduce the environmental pollutions and operating costs. The resilience and flexibility of the energy hub is also improved. Vehicle to grid and fully-partial charge models are incorporated for EVs to improve the system resilience and supplying the critical loads following events. Different events are modeled to evaluate the system resilience. The model is expressed as a stochastic mixed integer linear programming problem. Both active and reactive powers are modeled. The microgrid is simulated under four different cases. The results show that the multitype energy storages reduce the annual cost of energy while the integrated charging station can decrease the load shedding.©2022 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.fi=vertaisarvioitu|en=peerReviewed
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