StreetlightSim: a simulation environment to evaluate networked and adaptive street lighting

Sustaining the operation of street lights incurs substantial financial and environmental cost. Consequently, adaptive lighting systems have been proposed incorporating ad-hoc networking, sensing, and data processing, in order to better manage the street lights and their energy demands. Evaluating the efficiency and effectiveness of these complex systems requires the modelling of vehicles, road networks, algorithms, and communication systems, yet tools are not available to permit this. This paper proposes StreetlightSim, a novel simulation environment combining OMNeT++ and SUMO tools to model both traffic patterns and adaptive networked street lights. StreetlightSim’s models are illustrated through the simulation of a simple example, and a more complex scenario is used to show the potential of the tool and the obtainable results. StreetlightSim has been made open-source, and hence is available to the community

ACCELERATIVE STABILIZATION OF SOLID WASTE IN ANAEROBIC/AEROBIC LAB-SCALE LANDFILL BIOREACTORS

Joint Research on Environmental Science and Technology for the Eart

Finite-temperature Mott transitions in multi-orbital Hubbard model

We investigate the Mott transitions in the multi-orbital Hubbard model at half-filling by means of the self-energy functional approach. The phase diagrams are obtained at finite temperatures for the Hubbard model with up to four-fold degenerate bands. We discuss how the first-order Mott transition points $U_{c1}$ and $U_{c2}$ as well as the critical temperature $T_c$ depend on the orbital degeneracy. It is elucidated that enhanced orbital fluctuations play a key role to control the Mott transitions in the multi-orbital Hubbard model.Comment: 8 pages, 7 figure

Quantum Monte Carlo study of the formation of molecular polarizations and the antiferroelectric ordering in squaric acid crystals

Effects of geometrical frustration and quantum fluctuation are theoretically investigated for the proton ordering in a quasi-two-dimensional hydrogen-bonded system, squaric acid crystal. We elucidate the phase diagram for an effective model, the transverse-field Ising model on a frustrated checkerboard lattice, by using quantum Monte Carlo simulation. A crossover to liquidlike paraelectric state with well-developed molecular polarizations is identified, distinguishably from long-range ordering. Emergence of long-range order from the liquidlike state exhibits peculiar aspects originating from the lifting of quasi-macroscopic degeneracy, such as colossal enhancement of the transition temperature and a vanishingly small anomaly in the specific heat.Comment: 6 pages, 4 figures, accepted for publication in Physical Review

Three Lyα Emitting Galaxies within a Quasar Proximity Zone at z ~ 5.8

Quasar proximity zones at z > 5.5 correspond to overdense and overionized environments. Galaxies found inside proximity zones can therefore display features that would otherwise be masked by absorption in the intergalactic medium. We demonstrate the utility of this quasar-galaxy synergy by reporting the discovery of the first three “proximate Lyα emitters” (LAEs) within the proximity zone of quasar J0836+0054 at z = 5.795 (Aerith A, B, and C). Aerith A, located behind the quasar with an impact parameter D^{\perp} = 278 \pm 8 pkpc, provides the first detection of an Lyα transverse proximity effect. We model the transmission and show that it constrains the onset of J0836ʼs quasar phase to 0.2Myr < 28Myr < t in the past. The second object, Aerith B at a distance D < 912 pkpc from the quasar, displays a bright and broad double-peaked Lyα emission line. The peak separation implies a low ionizing f_{esc} \leqslant 1%. We fit the Lyα line with an outflowing shell model, finding a typical central density log N_{HI}/cm^{-2} = 19.3_{-0.2}^{+0.8}, outflow velocity v_{out} = 16_{-11}^{+4}km s^{-1}, and gas temperature log T/K = 3.8_{-0.7}^{+0.8} compared to 2 < z < 3 analog LAEs. We detect object Aerith C via an Lyα emission line at z = 5.726. This corresponds with the edge of the quasar’s proximity zone (Dz < 0.02), suggesting that the proximity zone is truncated by a density fluctuation. Via the analyses conducted here, we illustrate how proximate LAEs offer unique insight into the ionizing properties of both quasars and galaxies during hydrogen reionization

ABSOLUTE CONTINUITY AND HYPONORMAL OPERATORS

ABSTRACT. Let T be a completely hyponormal operator, wit

Quantum-thermal annealing with cluster-flip algorithm

A quantum-thermal annealing method using a cluster-flip algorithm is studied in the two-dimensional spin-glass model. The temperature (T) and the transverse field (Gamma) are decreased simultaneously with the same rate along a linear path on the T-Gamma plane. We found that the additional pulse of the transverse field to the frozen local spins produces a good approximate solution with a low computational cost.Comment: 4 pages, 3 figure

Poster Abstract: Solar-Powered Adaptive Street Lighting Evaluated with Real Traffic and Sunlight Data

Street lighting is an important resource; it has been shown to reduce crime, improve road safety, and increase economic activity. These benefits, however, come with a cost: an annual emission of 64 million tonnes of CO2. Solar-powered street lighting is attractive for its use of renewable energy and its ease of installation (particularly in off-grid applications), but sizing and control is a non-trivial task. This paper describes TALiSMaN-Green, a traffic-aware street lighting scheme which takes account of road users as well as the available energy to dynamically adjust lighting levels. Simulations using real traffic and sunlight data illustrate that solar-powered streetlights can be managed to deliver consistent usefulness throughout the night

Incommensurate state in a quasi-one-dimensional S=1/2S=1/2 bond-alternating antiferromagnet with frustration in magnetic fields

We investigate the critical properties of the $S=1/2$ bond-alternating spin chain with a next-nearest-neighbor interaction in magnetic fields. By the numerical calculation and the exact solution based on the effective Hamiltonian, we show that there is a parameter region where the longitudinal incommensurate spin correlation becomes dominant around the half-magnetization of the saturation. Possible interpretations of our results are discussed. We next investigate the effects of the interchain interaction ($J^{\prime}$). The staggered susceptibility and the uniform magnetization are calculated by combining the density-matrix renormalization group method with the interchain mean-field theory. For the parameters where the dominant longitudinal incommensurate spin correlation appears in the case $J^{\prime}=0$, the staggered long-range order does not emerge up to a certain critical value of $J^{\prime}$ around the half-magnetization of the saturation. We calculate the static structure factor in such a parameter region. The size dependence of the static structure factor at $k=2k_{\rm F}$ implies that the system has a tendency to form an incommensurate long-range order around the half-magnetization of the saturation. We discuss the recent experimental results for the NMR relaxation rate in magnetic fields performed for pentafluorophenyl nitronyl nitroxide.Comment: 10 pages, 12 figures, final version, to appear in PRB vol. 70, No. 5 (2004

Dynamical structure factors of S=1/2S=1/2 two-leg spin ladder systems

We investigate dynamical properties of $S=1/2$ two-leg spin ladder systems. In a strong coupling region, an isolated mode appears in the lowest excited states, while in a weak coupling region, an isolated mode is reduced and the lowest excited states become a lower bound of the excitation continuum. We find in the system with equal intrachain and interchain couplings that due to a cyclic four-spin interaction, the distribution of the weights for the dynamical structure factor and characteristics of the lowest excited states are strongly influenced. The dynamical properties of two systems proposed for ${\rm SrCu_2O_3}$ are also discussed.Comment: 5 pages, 6 figure