An Optimization Method for Mobile Edge Service Migration in Cyberphysical Power System

To relieve the pressure of processing computation-intensive applications on mobile devices and avoid high latency during data transmission, edge computing is proposed to solve this problem. Mobile edge computing (MEC) allows the deployment of MEC servers at the edge of the network to interact with users on the premise of low transmission delay, thereby improving the quality of service (QoS) for users. However, due to the high mobility of users, with the continuous change of geographical location, when users exceed the signal range of the MEC server, the services they request on the MEC server will also be migrated to other MEC servers. The handoff process may involve high response delays caused by service forwarding, thereby greatly degrading QoS. For the above problems, in this paper, a service migration optimization method based on transmission power control is proposed. First, according to the transmission power of the MEC server, the user’s activity range is divided into multiple subregions based on a Voronoi diagram. Therefore, there is one MEC server in each subregion, and the size of each subregion is adjusted by controlling the transmission power of the MEC server to minimize the number of wireless handoffs and the energy consumption of the MEC server. Then, the particle swarm optimization (PSO) is adopted to solve the above multiobjective optimization problem. Finally, the effectiveness of the proposed method is verified through extensive experiments.

High-Throughput Large-Aperture Prism Prefilter for Ultraviolet Resonance Raman Spectroscopy

For the acquisition of high-quality ultraviolet resonance Raman spectra of strongly scattering samples such as membrane protein suspensions, an f/3.5 Littrow prism prefilter has been designed, built, and characterized. This prefilter has a Czerny–Turner configuration, and its focal length is 25 cm. The apex angle of the dispersive prism (20°) was chosen to provide maximum performance in the 220 to 240 nm range. The prism prefilter significantly reduced stray background due to Rayleigh scattering and visible fluorescence, while maintaining a low dispersion of 1300 cm−1/mm at 253 nm as well as a large f/3.5 aperture. The sharpness of the transmission edge (at 242 nm, the T = 0% to 95% transition occurs in 1.3 nm) quantitates its effectiveness as a sharp-cut Rayleigh scattering filter. The total throughput of the prefilter is ∼60% at 235 nm and ∼50% at 632.8 nm. The utility of this prefilter is demonstrated by obtaining high signal-to-noise resonance Raman spectra of bacteriorhodopsin in a purple membrane suspension with 239.5 nm excitation.

New fluoroindate glass compositions

The limits of glass formation of new fluoroindate glass compositions have been determined for the basic systems InF3–BaF2–GdF3−20ZnF2−20SrF2–2XFn where × = Na, La and InF3–BaF2−20ZnF2−20SrF2−2GdF3–XFn, where × = Ca and Y. The incorporation of small amounts of GaF3 and/or GdF3 increases strongly the thermal glass stability. All the fluoroindate compositions studied are highly transparent in the mid-infrared range; their transmission edge is shifted beyond 7 μm and the theoretical attenuation coefficient, extrapolated at the CO laser wavelength emission, is typically α = 100 dB/km. Large bulks and preforms have been prepared allowing the drawing of optical fibers.