Non-preemptive Scheduling in a Smart Grid Model and its Implications on Machine Minimization

We study a scheduling problem arising in demand response management in smart grid. Consumers send in power requests with a flexible feasible time interval during which their requests can be served. The grid controller, upon receiving power requests, schedules each request within the specified interval. The electricity cost is measured by a convex function of the load in each timeslot. The objective is to schedule all requests with the minimum total electricity cost. Previous work has studied cases where jobs have unit power requirement and unit duration. We extend the study to arbitrary power requirement and duration, which has been shown to be NP-hard. We give the first online algorithm for the general problem, and prove that the problem is fixed parameter tractable. We also show that the online algorithm is asymptotically optimal when the objective is to minimize the peak load. In addition, we observe that the classical non-preemptive machine minimization problem is a special case of the smart grid problem with min-peak objective, and show that we can solve the non-preemptive machine minimization problem asymptotically optimally

Proof of the Double Bubble Conjecture in R^n

The least-area hypersurface enclosing and separating two given volumes in R^n is the standard double bubble.Comment: 20 pages, 22 figure

LOCK CONGESTION AND ITS IMPACT ON GRAIN BARGE RATES ON THE UPPER MISSISSIPPI RIVER

An anticipated increase in lock delays on the upper Mississippi River has generated concern about its future navigational efficiency. The objective of this paper is to identify selected factors affecting lock delay on the River's busiest locks and to examine the impact of lock delay on grain barge rates. Results show that lock unavailability, traffic level, and delay at nearby locks affect lock delay. Further, barge rates are affected by lock delay, however, the impact is modest.Public Economics,

Cointegration and Causality Analysis of World Vegetable Oil and Crude Oil Prices

Because of the recent soaring petroleum price and growing environmental concerns, biodiesel has become an important alternative fuel. Biodiesel is the mono alky esters made from a vegetable oil, such as soybean or rapeseed oil, or sometimes from animal fats. The escalation in world petroleum price has stimulated the demand for biodiesel, which consequently expanded the use of vegetable oils. This paper investigates the long-run interdependence between major edible oil prices and examines the dynamic relationship between vegetable and crude oil prices. The data consists of 378 weekly observations extending from the first week of January in 1999 to the fourth week of March in 2006. We apply time-series analytical mechanisms and directed acyclic graphs to four major traded edible oils prices, including soybean, sunflower, rapeseed and palm oils, along with one weighted average world crude oil price. Tentative results suggest one long-run cointegration relationship among those five oil prices. Also, the edible oil markets are well linked in contemporaneous time with the palm oil market initiating the new information; however, soybean oil price dominates the edible oil markets in the long run. The influence of crude oil price on edible oil prices is not significant over the study period.Resource /Energy Economics and Policy,

Briefing Paper on the Upper Mississippi and Illinois Rivers Transportation Corridors: Grain Transportation Rates and Associated Market Area

This paper discusses the grain transportation rates and associated market areas of the upper Mississippi and Illinois Rivers transportation corridors

Real-time observation of a coherent lattice transformation into a high-symmetry phase

Excursions far from their equilibrium structures can bring crystalline solids through collective transformations including transitions into new phases that may be transient or long-lived. Direct spectroscopic observation of far-from-equilibrium rearrangements provides fundamental mechanistic insight into chemical and structural transformations, and a potential route to practical applications, including ultrafast optical control over material structure and properties. However, in many cases photoinduced transitions are irreversible or only slowly reversible, or the light fluence required exceeds material damage thresholds. This precludes conventional ultrafast spectroscopy in which optical excitation and probe pulses irradiate the sample many times, each measurement providing information about the sample response at just one probe delay time following excitation, with each measurement at a high repetition rate and with the sample fully recovering its initial state in between measurements. Using a single-shot, real-time measurement method, we were able to observe the photoinduced phase transition from the semimetallic, low-symmetry phase of crystalline bismuth into a high-symmetry phase whose existence at high electronic excitation densities was predicted based on earlier measurements at moderate excitation densities below the damage threshold. Our observations indicate that coherent lattice vibrational motion launched upon photoexcitation with an incident fluence above 10 mJ/cm2 in bulk bismuth brings the lattice structure directly into the high-symmetry configuration for tens of picoseconds, after which carrier relaxation and diffusion restore the equilibrium lattice configuration.Comment: 22 pages, 4 figure

Modeling Turbidity Currents Using the Multiple-state Discrete-time Markov Chain Approach

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchive

Fluctuation-induced forces between inclusions in a fluid membrane under tension

We discuss the fluctuation-induced force, a finite-temperature analog of the Casimir force, between two inclusions embedded in a fluid membrane under tension. We suggest a method to calculate this Casimir interaction in the most general case, where membrane fluctuations are governed by the combined action of surface tension, bending modulus, and the Gaussian rigidity. We find that the surface tension strongly modifies the power law in the separation dependence of the Casimir interaction. This results in a strong suppression of the Casimir force at separations beyond a characteristic length, which could affect protein aggregation dynamics in cell membranes.Comment: 4 pages, 1 figur