Reducing Electricity Demand Charge for Data Centers with Partial Execution

Data centers consume a large amount of energy and incur substantial electricity cost. In this paper, we study the familiar problem of reducing data center energy cost with two new perspectives. First, we find, through an empirical study of contracts from electric utilities powering Google data centers, that demand charge per kW for the maximum power used is a major component of the total cost. Second, many services such as Web search tolerate partial execution of the requests because the response quality is a concave function of processing time. Data from Microsoft Bing search engine confirms this observation. We propose a simple idea of using partial execution to reduce the peak power demand and energy cost of data centers. We systematically study the problem of scheduling partial execution with stringent SLAs on response quality. For a single data center, we derive an optimal algorithm to solve the workload scheduling problem. In the case of multiple geo-distributed data centers, the demand of each data center is controlled by the request routing algorithm, which makes the problem much more involved. We decouple the two aspects, and develop a distributed optimization algorithm to solve the large-scale request routing problem. Trace-driven simulations show that partial execution reduces cost by $3\%--10.5\%$ for one data center, and by $15.5\%$ for geo-distributed data centers together with request routing.Comment: 12 page

Performance Analysis of Free-space Quantum Key Distribution Using Multiple Spatial Modes

In the diffraction-limited near-field propagation regime, free-space optical quantum key distribution (QKD) systems can employ multiple spatial modes to improve their key rate. Here, we analyze QKD using the non-orthogonal flat-top focused beams. Although they suffer from a rate penalty, their ease of implementation makes them an attractive alternative to the well-studied orthonormal Laguerre-Gauss (LG) modes. Indeed, in the presence of turbulence, the non-orthogonal modes may achieve higher QKD rate than the LG modes.Comment: 13 pages, 5 figures (if I count all the subfigures the total number is 9) submitted to Optics expres

Revisiting Deniability in Quantum Key Exchange via Covert Communication and Entanglement Distillation

We revisit the notion of deniability in quantum key exchange (QKE), a topic that remains largely unexplored. In the only work on this subject by Donald Beaver, it is argued that QKE is not necessarily deniable due to an eavesdropping attack that limits key equivocation. We provide more insight into the nature of this attack and how it extends to other constructions such as QKE obtained from uncloneable encryption. We then adopt the framework for quantum authenticated key exchange, developed by Mosca et al., and extend it to introduce the notion of coercer-deniable QKE, formalized in terms of the indistinguishability of real and fake coercer views. Next, we apply results from a recent work by Arrazola and Scarani on covert quantum communication to establish a connection between covert QKE and deniability. We propose DC-QKE, a simple deniable covert QKE protocol, and prove its deniability via a reduction to the security of covert QKE. Finally, we consider how entanglement distillation can be used to enable information-theoretically deniable protocols for QKE and tasks beyond key exchange.Comment: 16 pages, published in the proceedings of NordSec 201

HNC, HCN and CN in Seyfert galaxies

Bright HNC 1--0 emission has been found towards several Seyfert galaxies. This is unexpected since traditionally HNC is a tracer of cold (10 K) gas, and the molecular gas of luminous galaxies like Seyferts is thought to have bulk kinetic temperatures surpassing 50 K. In this work we aim to distinguish the cause of the bright HNC and to model the physical conditions of the HNC and HCN emitting gas. We have used SEST, JCMT and IRAM 30m telescopes to observe HNC 3-2 and HCN 3-2 line emission in a selection of 5 HNC-luminous Seyfert galaxies. We estimate and discuss the excitation conditions of HCN and HNC in NGC 1068, NGC 3079, NGC 2623 and NGC 7469, based on the observed 3-2/1-0 line intensity ratios. We also observed CN 1-0 and 2-1 emission and discuss its role in photon and X-ray dominated regions. HNC 3-2 was detected in 3 galaxies (NGC 3079, NGC 1068 and NGC 2623). HCN 3-2 was detected in NGC 3079, NGC 1068 and NGC 1365. The HCN 3-2/1-0 ratio is lower than 0.3 only in NGC 3079, whereas the HNC 3-2/1-0 ratio is larger than 0.3 only in NGC 2623. The HCN/HNC 1-0 and 3-2 line ratios are larger than unity in all the galaxies. The HCN/HNC 3-2 line ratio is lower than unity only in NGC 2623, similar to Arp 220, Mrk 231 and NGC 4418. In three of the galaxies the HNC emissions emerge from gas of densities n<10^5 cm^3, where the chemistry is dominated by ion-neutral reactions. In NGC 1068 the emission of HNC emerges from lower (<10^5 cm^3) density gas than HCN (>10^5 cm^3). Instead, the emissions of HNC and HCN emerge from the same gas in NGC 3079. The observed HCN/HNC and CN/HCN line ratios favor a PDR scenario, rather than an XDR one. However, the N(HNC)/N(HCN) column density ratios obtained for NGC 3079 can be found only in XDR environments.Comment: Accepted for publication in A&A. A selection of this paper will be presented as a poster in the FIR workshop 2007, held at Bad Honnef, Germany. High resolution figures in original paper. 16 pages, 8 figure

Sustainable green energy management : Optimizing scheduling of multi-energy systems considered energy cost and emission using attractive repulsive shuffled frog-leaping

As energy systems become increasingly complex, there is a growing need for sustainable and efficient energy management strategies that reduce greenhouse gas emissions. In this paper, multi-energy systems (MES) have emerged as a promising solution that integrates various energy sources and enables energy sharing between different sectors. The proposed model is based on using an Attractive Repulsive Shuffled Frog-Leaping (ARSFL) algorithm that optimizes the scheduling of energy resources, taking into account constraints such as capacity limitations and environmental regulations. The model considers different energy sources, including renewable energy and a power-to-gas (P2G) network with power grid, and incorporates a demand–response mechanism that allows consumers to adjust their energy consumption patterns in response to price signals and other incentives. The ARSFL algorithm demonstrates superior performance in managing and minimizing energy purchase uncertainty compared to the particle swarm optimization (PSO) and genetic algorithm (GA). It also exhibits significantly reduced execution time, saving approximately 1.59% compared to PSO and 2.7% compared to GA

Processing and Technology of Fruits and Vegetables, 1960

Tomato Variety Evaluation for Processing, 1961 / W. A. Gould, J. R. Geisman and Wade Schulte -- Evaluation of Sweet Corn Varieties for Processing / J. R. Geisman and W. A. Gould -- Small Fruit Variety Evaluation Studies for Freezing / D. R. Davis and H. L. Stammer -- Evaluation of Apples for Processing. I. Fruit Juice Blends / D. R. Davis and H. L. Stammer -- Evaluation of Apples for Processing. II. Canned Apple Slices / D. R. Davis and H. L. Stammer -- Evaluation of Apples for Processing. III. Frozen Apple Slices / D. R. Davis and H. L. Stammer -- Evaluation of Apples for Processing. IV. Frozen Fruit Pies / D. R. Davis and H. L. Stammer -- A Study of Several Varieties of Pumpkin and Squash for Canning and Freezing for Use in Pies / Robert H. Clayton, J. R. Geisman and W. A. Gould -- Factors Effecting the Consistency of Cream Style Corn / D. R. Davis and W. A. Gould -- The Objective Measurement of Tomato Juice Consistency / Robert Kluter and W. A. Gould -- A Method for the Detection of Drosophila Fly Eggs and Larvae in Tomato Products / J. R. Geisman and Winston D. Bash -- A Chemical Study of Flavor and Flavor Substances in Tomatoes / John Hal Johnson and W. A. Gould -- Tannin Content Effects Grape Juice Quality / D. R. Davis and H. L. Stammer -- pH Survey for Tomatoes in Ohio / W. D. Bash -- Flavor Studies with Sauerkraut / J. R. Geisman, S. S. Verma and W. A. Gould -- The Effect of Fill Weight on Drained Weight of Canned Tomatoes / Wade A. Schulte and W. A. Gould -- A New Method for the Manufacture of Apple Sirup / M. P. Baldauf, D. R. Davis and H. L. Stammer -- Studies on Color Retention in Canned R.T.P. Cherries / D. R. Davis and H. L. Stammer -- Clumping Studies in Canned Blueberries / D. R. Davis and H. L. Stammer -- Infra-red Peeling Studies. I. Apples. / L. Lafferty and W. A. Gould -- Infra-red Peeling Studies. II. Tomatoes. / W. A. Gould, Richard Leiss and Donall Streets -- The Effect of Water Holding Times and Temperatures on Quality of Tomatoes / Richard Leiss, Ernest Anderson and W. A. Gould -- Quality Attributes of Sweet Potatoes - Glass Packed / Donald A. Giesser and W. A. Gould -- A Study of Some of the Factors Effecting the Efficiency of Washing of Fruits and Vegetables. I. Tomatoes / W. A. Gould and J. R. Geisman -- A Study of Some of the Factors Effecting the Efficiency of Washing of Fruits and Vegetables. II. Sweet Corn / J. R. Geisman and W. A. Gould -- A Study of Alpha-keto Acids, Amino Acids, and Citric Acid in Eight Tomato Varieties, and Their Changes During Processing / Mokhtar M. Hamdy and W. A. Goul