292 research outputs found

    A tabu search heuristic for routing in WDM networks.

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    Optical networks and Wavelength-Division Multiplexing (WDM) have been widely studied and utilized in recent years. By exploiting the huge bandwidth of optical networks, WDM appears to be one of the most promising technologies to meet the dramatically increased demand for bandwidth. Since optical resources in optical networks are very expensive, development of dynamic lightpath allocation strategies, which utilize network resource efficiently, is an important area of research. We assume that there is no optical wavelength conversion device in the network, and the wavelength-continuity constraint must be satisfied. Exact optimization techniques are typically too time-consuming to be useful for practical-sized networks. In this thesis we present a tabu search based heuristic approach which is used to establish an optimal lightpath dynamically in response to a new communication request in a WDM network. As far as we know, this is the first investigation using tabu search techniques for dynamical lightpath allocation in WDM networks. We have tested our approach with networks having different sizes. And then we have compared our results with those obtained using the MILP approach. In the vast majority of cases, tabu search was able to quickly generate a solution that was optimal or near-optimal, indicating that tabu search is a promising approach for the dynamic lightpath allocation problem in WDM networks. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2004 .W36. Source: Masters Abstracts International, Volume: 43-01, page: 0247. Advisers: Subir Bandyopadhyay; Arunita Jaekel. Thesis (M.Sc.)--University of Windsor (Canada), 2004

    Executives Political Connection and Over-investment in New Energy Companies:Empirical Evidence from China\u27s Capital Market

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    Establishing links between business and government is a common phenomenon in the world. Using data of new energy companies listed in Shenzhen and Shanghai Stock Exchange,the paper examines the relationship between political connection and firms’ over-investment. We find that executives political connection is a significant promotion of firms’ over-investment; the political connection is divided into the central- and local-level, and further tests find that political connections with different levels have no significant impact on firms’ over-investment. Our findings provide an empirical evidence for strengthening the Governance Reform of the government

    Effect of yaw angle on flow structure and cross-flow force around a circular cylinder

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    Flow around an inclined circular cylinder at yaw angles of α = 0°, 30°, 45°, and 60° has been numerically studied using the delayed detached eddy simulation at a Reynolds number of 1.4 × 104. Periodic boundary conditions are utilized to minimize the end effect. The focus is to explore the effect of yaw angle on the flow structure and the spatial distribution of the cross-flow forces. For the normal flow case, the modulation of the span-wise averaged lift force coefficient is found to be related to the unstable shear layer. For the inclined cases, contours of the sectional lift force coefficient show that the local vortex shedding staggers in time along the axial span at the early stage of the simulation, when the flow approaches the cylinder. After the flow reaches the quasi-periodic state, the axial difference disappears for α \u3e 45° but not for α = 30°. In particular, the axial difference of the sectional lift force coefficient results in a near-zero value of the span-wise averaged lift force coefficient. The transition from a two-dimensional flow to a three-dimensional one is not captured in the current simulation. However, wake visualization indicates a mitigation of von Kármán vortex shedding when the yaw angle is greater than 30°. Although the Strouhal number is well predicted by the Independence Principle (IP), other flow properties are less agreeable with the prediction by IP

    Scoulerine promotes cytotoxicity and attenuates stemness in ovarian cancer by targeting PI3K/AKT/mTOR axis

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    In women, ovarian cancer is a common gynecological cancer associated with poor prognosis, reoccurrence and chemoresistance. Scoulerine, a benzylisoquinoline alkaloid, has been reported effective against several carcinomas. Thus, we investigated the impact of scoulerine on ovarian cancer cells (OVCAR3). Cell viability was assessed by MTT assay, migration was determined by Boyden Chamber assay, while the invasion was monitored by Boyden Chamber assay using the matrigel. The stemness properties of OVCAR3 cells were observed by tumorsphere assay. Epithelial to mesenchymal transition (EMT) and stemness-related protein markers were monitored by real-time PCR analysis and immunoblotting. Scoulerine inhibits the viability of OVCAR3 cells with the IC50 observed at 10 µmol L–1 after 48 h treatment. Scoulerine inhibited the colony-forming ability, migration and invasiveness of OVCAR3 cells in a dose-dependent fashion. Scoulerine treatment also drastically reduced the spheroid-forming ability of OVCAR3 cells. The mesenchymal and stemness-related markers like N-cadherin, vimentin, CD-44, Oct-4, Sox-2 and Aldh1A1 were downregulated, whereas the epithelial markers like E-cadherin and CD-24 were upregulated in scoulerine-treated cells. The upstream PI3K/Akt/mTOR-axis was downregulated in scoulerine-treated cells. We concluded that scoulerine successfully perturbs the cancerous properties of OVCAR3 cells by targeting the PI3K/Akt/mTOR axis. In vivo studies revealed a substantial decrease in tumor mass and volume after scoulerine treatment. Furthermore, scoulerine treatment was found to decrease oxidative stress factors in ovarian cancer mice model. Scoulerine is a potential anticancer agent against ovarian cancer and can be considered as a lead molecule for this malignancy, provided further investigations are performed

    Bis(2,2′-bipyridyl-κ2 N,N′)bis­(dicyanamido-κN)manganese(II)

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    In title complex, [Mn(C2N3)2(C10H8N2)2], the MnII ion is coordinated in a slightly distorted octa­hedral geometry by six N atoms. Four of the N atoms are from two chelating bipyridine ligands and two are from a pair of cis-coordinated dicyanamide ligands. The dihedral angle formed by the mean planes of the bipyridine rings is 85.93 (14)°. The central N atom of one of the dicyanamide ligands was refined as disordered over two sites with equal occupancies

    Chlorido[4-chloro-2-(pyridin-2-yl­methyl­imino­meth­yl)phenolato-κ3 N,N′,O]copper(II)

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    In the title complex, [Cu(C13H10ClN2O)Cl], the CuII ion is coordinated by one O atom and two N atoms of the tridentate Schiff base ligand and one chloride ion, forming a slightly distorted square-planar geometry. Weak Cu⋯Cl inter­actions [2.793 (5) Å] result in the formation of a chain along the a axis

    A Pilot Study on Real-time Monitoring of Heart Rate and Movement Speed in Middle-distance Race of Physical Education Classes

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    In Chinese universities, students need to participate in the middle-distance-race. Normally, female students are required to participate in the race of 800 meters, while male students are required to participate in the race of 1000 meters. However, it is difficult for teachers to grasp the real time information of students during the race. And there is a lack of timely communications between the teachers and students. Focusing on this issue, this study, with the use of POLAR heart rate sensor and other modern information technologies, expands the original function of the sensor to achieve a concurrent operation of detecting heart rates and automatically measuring the movement speed. The researchers have successfully designed a micro system to monitor the process of middle-distance race. Moreover, the study also engages in a preliminary experiment verification so as to provide object and effective reference and basis for the middle-distance race physical education teaching in universities

    Measuring cosmic filament spin with the kinetic Sunyaev-Zel'dovich effect

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    The spin of intergalactic filaments has been predicted from simulations, and supported by tentative evidence from redshift-space filament shapes in a galaxy redshift survey: generally, a filament is redshifted on one side of its axis, and blueshifted on the other. Here, we investigate whether filament spins could have a measurable kinetic Sunyaev-Zel'dovich (kSZ) signal, from CMB photons being scattered by moving ionised gas; this pure velocity information is complementary to filament redshift-space shapes. We propose to measure the kSZ dipole by combining galaxy redshift surveys with CMB experiments. We base our S/N analyses first on an existing filament catalogue, and its combination with Planck data. We then investigate the detectability of the kSZ dipole using the combination of DESI or SKA-2 with next-stage CMB experiments. We find that the gas halos of filament galaxies co-rotating with filaments induce a stronger kSZ dipole signal than that from the diffuse filamentary gas, but both signals seem too small to be detected in near-term surveys such as DESI+future CMB experiments. But the combination of SKA-2 with future CMB experiments could give a more than 10σ\sigma detection. The gain comes mainly from an increased area overlap and an increased number of filaments, but also the low noise and high resolution in future CMB experiments are important to capture signals from filaments small on the sky. Successful detection of the signals may help to find the gravitomagnetic effect in large-scale structure and advance our understanding of baryons in the cosmic web.Comment: Minor revisions, MNRAS accepte

    Effects of Fallow Management Practices on Soil Water, Crop Yield and Water Use Efficiency in Winter Wheat Monoculture System: A Meta-Analysis

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    Winter wheat monoculture is a predominant cropping system for agricultural production in dry areas. However, fallow management effects on soil water conservation and crop yield and water use have been inconsistent among studies. We selected 137 studies and performed a meta-analysis to test the effects of tillage and mulching during the fallow period on precipitation storage efficiency (PSE), soil water storage at wheat planting (SWSp), crop yield, evapotranspiration (ET), and water use efficiency (WUE). Compared to conventional tillage (CT), conservation tillage during fallow period overall increased PSE, SWSp and wheat yield by 31.0, 6.4, and 7.9%, respectively, but did not affect ET and WUE. No tillage (NT) had a better performance on soil water conservation during fallow period but a similar effect on wheat yield and WUE compared to reduced tillage (RT) and subsoil tillage (ST). Compared to no mulching, fallow mulching practices overall increased PSE by 19.4%, but had a non-significant impact on SWSp, wheat yield, and ET. Compared to straw mulching, film mulching, and stubble mulching during fallow period, cover cropping as a biological mulching decreased SWSp, wheat yield, and WUE significantly. Wheat WUE was improved by straw mulching but not affected by film mulching and stubble mulching. Strong interactions between tillage method and mulching practices were found for most variables. NT with fallow mulching or with no mulching exhibited a greater impact on soil water conservation during fallow period compared to other combinations. The effects of tillage and mulching during fallow period on soil water conservation and wheat yield and water use also varied with soil and climatic conditions. Overall, NT in combination with straw mulching significantly increased SWSp, PSE, wheat yield, and WUE and can be the best fallow management practice for winter wheat production in varying edaphic and climatic conditions
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