Digraph-based joint routing and resource allocation in software-defined backhaul networks

By decoupling the control plane from the data plane and providing programmability for network applications, software-defined network (SDN) is positioned to offer more efficient management, higher flexibility and better performance. Routing and resource allocation are two closely related applications in wireless networks. With close cooperation, better performance and lower complexity can be achieved in an SDN architecture. However, work that jointly studies routing and resource allocation is rarely seen. In this paper, the joint routing and resource allocation problem is investigated in OFDMA-based software-defined backhaul networks (SDBN). To exploit the SDN programmability, an SDBN system model is proposed, where the control panel can use high complexity algorithms in configuration phase in order to simplify algorithms in operation phases. Then the joint routing and resource allocation problem is formulated as a system throughput optimization problem. By constructing the interference digraph of the network and analysing the vertex degree characteristics, a digraph-based greedy algorithm (DBGA) is proposed. Simulation results have shown that, the proposed DBGA works well to increase the system throughput

Measurement back-action on the quantum spin-mixing dynamics of a spin-1 Bose-Einstein condensate

We consider a small F=1 spinor condensate inside an optical cavity driven by an optical probe field, and subject the output of the probe to a homodyne detection, with the goal of investigating the effect of measurement back-action on the spin dynamics of the condensate. Using the stochastic master equation approach, we show that the effect of back-action is sensitive to not only the measurement strength but also the quantum fluctuation of the spinor condensate. The same method is also used to estimate the atom numbers below which the effect of back-action becomes so prominent that extracting spin dynamics from this cavity-based detection scheme is no longer practical

Coverage Analysis of Reduced Power Subframes Applied in Heterogeneous Networks with Subframe Misalignment Interference

IEEE In heterogeneous networks (HetNets), to reduce the interference to users in Cell Range Expansion (CRE) areas of small cells, Reduced Power Subframes (RPSs) are used by macro base stations (BSs) to serve their center region users. CRE users can receive full power subframes (FPSs) from small-cell BSs in the same time slots as RPSs. However, it is difficult to maintain strict subframe alignment (SA) between neighbouring cells. Subframe misalignment (SM) between RPSs and FPSs transmitted by neighbouring macro BSs and small-cell BSs may degrade the coverage performance for macrocell center and small-cell CRE users. With existing time synchronization techniques used in HetNets, the SM offsets are actually upper-bounded. In this letter, we propose a novel SM model for a two-tier HetNet adopting RPSs with SM offsets restricted within a subframe duration, and analyse the coverage probability under the effects of RPSs and SM based on stochastic geometry. The results show that the strict SA requirement can be relaxed by up to 20% of subframe duration with below 5% coverage loss

Properties of a coupled two species atom-heteronuclear molecule condensate

We study the coherent association of a two-species atomic condensate into a condensate of heteronuclear diatomic molecules, using both a semiclassical treatment and a quantum mechanical approach. The differences and connections between the two approaches are examined. We show that, in this coupled nonlinear atom-molecule system, the population difference between the two atomic species plays a significant role in the ground-state stability properties as well as in coherent population oscillation dynamics.Comment: 7 pages, 4 figure

Study on Salting Out-Steam Distillation Extraction Technology and Antibacterial Activities of Essential Oil From Cumin Seeds

The effects of different factors on the yield of essential oil from were discussed, and the extraction conditions of essential oil from cumin seeds by salting out-steam distillation technology based on single-factor test and orthogonal experiment, as well as its antibacterial activities on several common food spoilage bacteria were studied in this paper. The results showed that, the impact order of the influence factors was liquid/solid ratio > distilling time > NaCl concentration, and optimized extraction conditions were as follows, liquid to material ratio 15:1, soaking time 1 h, 4% NaCl, steam distilling time 3 h. The yield of essential oil was up to 4.48% under these conditions. The results of antibacterial activity assays showed that the essential oil from cumin seeds exhibited the different antibacterial activities against some food borne pathogens, especially it presented the best inhibitory effect against Bacillus subtilis with the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 6.25 and 12.5 mg/mL respectively, followed by Staphylococcus albus and Staphylococcus aureus, the lowest for Pseudomonas aeruginosa and Shigella dysenteria