Two Particle States in a Box and the ss-Matrix in Multi-Channel Scattering

Using a quantum mechanical model, the exact energy eigenstates for two-particle two-channel scattering are studied in a cubic box with periodic boundary conditions. A relation between the exact energy eigenvalue in the box and the two-channel $S$-matrix elements in the continuum is obtained. This result can be viewed as a generalization of the well-known L\"uscher's formula which establishes a similar relation in elastic scattering.Comment: 4 pages, typeset with ws-ijmpa.cls. Talk presented at International Conference on QCD and Hadronic Physics, June 16-20, 2005, Beijing, China. One reference adde

MODEL-BASED TESTING AND EVALUATION OF SORPTION MEDIA FOR REMOVING VOLATILE ORGANIC COMPOUNDS IN INDOOR AIR

Volatile Organic Compounds (VOCs), which may cause short and long term adverse health effects, constitute a significant class of indoor gaseous pollutants. To reduce the VOC concentration of indoor environment, an in-depth understanding of the performance of the air cleaning technologies that address VOCs is important. Although many studies have been conducted to evaluate the performance of air cleaning devices, most of them were performed at elevated concentration level (~ppmv). The performance of the sorbent media at realistic VOC concentration (ppbv) is still not clear due to lack of experiment data and theoretical study. The test conducted under the low concentration is not cost-effective and difficult to perform. Currently, no mathematical model can be effectively used for sorbent media performance simulation at ppb level. The main objective of the presented research is to investigate the adsorption mechanism, address the existing problems through a model-based testing and evaluation method, develop and validate reliable methodologies to predict the long-term performance of filter sorbent media, when exposed to the realistic indoor concentration of VOCs. A series of long-term tests were conducted at six concentration levels from 100 ppm to 66 ppb, and different test conditions (particle size, flow rate and sorbent bed length) to reveal the different behavior of the filter media at different concentration levels. A new mechanistic model named convective & diffusion mass transfer model with variable partition coefficient (C&DMT-VP) was proposed to simulate the performance of adsorption-based air cleaning devices under the typical indoor VOC concentrations. The applications of this model were demonstrated, including the determination of the surface diffusion coefficient, prediction of sorbent media filter performance via C&DMT-VP at typical indoor concentration level based on the model parameters determined from different test methods, including the ASHRAE standard test 145.1, ground pellet test and thin layer with ground pellet test. Finally, the proposed methods were compared and validated with the experimental data. It was found that 1) the partition coefficient varied with the concentration in the form of (or ; 2) The C&DMT-VP model incorporating the K(C) relationship significantly improved the representation of the performance at the low concentration as well as being able to represent the high concentration performance as in previous model; 3) The three accelerated methods were able to provide the data needed to determine the function for a given adsorption media’s performance at low concentrations typically found indoors

3E: Energy-Efficient Elastic Scheduling for Independent Tasks in Heterogeneous Computing Systems

Reducing energy consumption is a major design constraint for modern heterogeneous computing systems to minimize electricity cost, improve system reliability and protect environment. Conventional energy-efficient scheduling strategies developed on these systems do not sufficiently exploit the system elasticity and adaptability for maximum energy savings, and do not simultaneously take account of user expected finish time. In this paper, we develop a novel scheduling strategy named energy-efficient elastic (3E) scheduling for aperiodic, independent and non-real-time tasks with user expected finish times on DVFS-enabled heterogeneous computing systems. The 3E strategy adjusts processors’ supply voltages and frequencies according to the system workload, and makes trade-offs between energy consumption and user expected finish times. Compared with other energy-efficient strategies, 3E significantly improves the scheduling quality and effectively enhances the system elasticity

KSS unit root test of nonlinearity and nonstationarity in China’s agricultural futures markets

AbstractUnit root tests are the starting points of most economic time series analyses. Based on the nonlinear unit root test proposed by Kapetanios, Shin and Shell (KSS), this article propose a procedure to detect the presence of nonstationarity against nonlinear processes in 5 representative China’s agricultural futures markets. Our results illustrate that a unit root is rejected in favor of nonlinear trend stationary for these markets; therefore, the results in current literature based on the linear hypothesis may be spurious in understanding true market’s dynamics. We contribute to current literature in providing for the first time the empirical evidence of these facts in China’s agricultural futures markets, which is fundamentally important in relevant researches

Newton-CG methods for nonconvex unconstrained optimization with H\"older continuous Hessian

In this paper we consider a nonconvex unconstrained optimization problem minimizing a twice differentiable objective function with H\"older continuous Hessian. Specifically, we first propose a Newton-conjugate gradient (Newton-CG) method for finding an approximate first-order stationary point (FOSP) of this problem, assuming the associated the H\"older parameters are explicitly known. Then we develop a parameter-free Newton-CG method without requiring any prior knowledge of these parameters. To the best of our knowledge, this method is the first parameter-free second-order method achieving the best-known iteration and operation complexity for finding an approximate FOSP of this problem. Furthermore, we propose a Newton-CG method for finding an approximate second-order stationary point (SOSP) of the considered problem with high probability and establish its iteration and operation complexity. Finally, we present preliminary numerical results to demonstrate the superior practical performance of our parameter-free Newton-CG method over a well-known regularized Newton method.Comment: arXiv admin note: text overlap with arXiv:2301.0313