Joint Interference Alignment and Bi-Directional Scheduling for MIMO Two-Way Multi-Link Networks

By means of the emerging technique of dynamic Time Division Duplex (TDD), the switching point between uplink and downlink transmissions can be optimized across a multi-cell system in order to reduce the impact of inter-cell interference. It has been recently recognized that optimizing also the order in which uplink and downlink transmissions, or more generally the two directions of a two-way link, are scheduled can lead to significant benefits in terms of interference reduction. In this work, the optimization of bi-directional scheduling is investigated in conjunction with the design of linear precoding and equalization for a general multi-link MIMO two-way system. A simple algorithm is proposed that performs the joint optimization of the ordering of the transmissions in the two directions of the two-way links and of the linear transceivers, with the aim of minimizing the interference leakage power. Numerical results demonstrate the effectiveness of the proposed strategy.Comment: To be presented at ICC 2015, 6 pages, 7 figure

Dynamic Pricing of Substitutable Products in the Presence of Capacity Flexibility

Firms that offer multiple products are often susceptible to periods of inventory mismatches where one product may face shortages while the other has excess inventories. In this paper, we study a joint implementation of price- and capacity-based substitution mechanisms to alleviate the level of such inventory disparities. We consider a firm producing substitutable products via a capacity portfolio consisting of both product-dedicated and flexible resources and characterize the structure of the optimal production and pricing decisions. We then explore how changes in various problem parameters affect the optimal policy structure. We show that the availability of a flexible resource helps maintain stable price differences across products over time even though the price of each product may fluctuate over time. This result has favorable ramifications from a marketing standpoint because it suggests that even when a firm applies a dynamic pricing strategy, it may still establish consistent price positioning among multiple products if it can employ a flexible replenishment resource. We provide numerical examples for the price stabilization effect and discuss extensions of our results to a more general multiple product setting

Simulation of higher harmonics generation in tapping-mode atomic force microscopy

Cataloged from PDF version of article.In tapping-mode atomic force microscopy, nonlinear tip–sample interactions give rise to higher harmonics of the cantilever vibration. We present an electrical circuit to model the atomic force microscope cantilever with its first three flexural eigenmodes. An electrical circuit simulator is used to simulate the tapping-mode operation. Amplitude and phase responses of the third flexural eigenmode are obtained for different sample properties. It is found that amplitude and phase of higher harmonics depend highly on sample properties. © 2001 American Institute of Physic

A laboratory study of the effects of water dissolved gypsum application on hydraulic conductivity of saline-sodic soil under intermittent ponding conditions

peer-reviewedReclamation of saline-sodic soils has great importance in agricultural management. The objective of this study was to evaluate the effectiveness of the methods used to apply water and gypsum on hydraulic conductivity of a saline-sodic soil with an electrical conductivity of 28 dS/m and exchangeable sodium percentage of 46%. The experiment was conducted under laboratory conditions using disturbed and non-cropped soil columns. A total of 45 cm of water was applied to each column with 3, 6, or 9 separate water applications. Finely ground gypsum (< 0.5 mm maximum particle diameter) was either incorporated into the surface 2 to 3 cm of soil or was dissolved into the leaching water at a rate corresponding to 3.82 t/ha. Six or nine separate water applications of gypsum dissolved into leaching water significantly increased hydraulic conductivity (P < 0.01). Soil hydraulic conductivity increased (P < 0.01) with depth at separate applications of gypsum

Analysis of tip-sample interaction in tapping-mode atomic force microscope using an electrical circuit simulator

Cataloged from PDF version of article.We present a mechanical model for the atomic force microscope tip tapping on a sample. The model treats the tip as a forced oscillator and the sample as an elasticmaterial with adhesiveproperties. It is possible to transform the model into an electrical circuit, which offers a way of simulating the problem with an electrical circuit simulator. Also, the model predicts the energy dissipation during the tip–sample interaction. We briefly discuss the model and give some simulation results to promote an understanding of energy dissipation in a tapping mode. © 2001 American Institute of Physic

Efecto de ciclos congelación-deshielo en la estabilidad de los agregados del suelo en diversas condiciones de salinidad y sodicidad

Freezing and thawing affect soil aggregate stability. Understanding the effects of freezing and thawing processes on aggregate stability is necessary for the development of strategies for managing saline-sodic soils. This study was performed to determine the effects of freezing and thawing cycles (two, four, and six) on wet aggregate stability in six soils of different salinity and sodicity (54 dS/m, 11.7%; 49 dS/m, 11.8%; 53 dS/m, 31.7%; 85 dS/m, 39.7%; 59 dS/m, 13.9%; 68 dS/m, 36.8%, respectively) and three different aggregate sizes (< 1, 1-2, and 2-4 mm). The experiments were conducted under laboratory conditions using disturbed and non-cropped soil samples. In soils with a high percentage of exchangeable sodium and high electrical conductivity, the effect of freeze-thaw cycles on the wet aggregate stability was not significant. However, when the electrical conductivity was high and the percentage exchangeable sodium relatively low, wet aggregate stability was significantly reduced by the freeze-thaw cycles. Moreover, for aggregate sizes of 1-2 and 2-4 mm, a significant reduction (PPara desarrollar estrategias de manejo de suelos salino-sódicos, es necesario entender los efectos de los procesos de congelación y deshielo sobre la estabilidad de los agregados. Se realizó este estudio para determinar los efectos de ciclos hielo-deshielo (dos, cuatro o seis ciclos) en la estabilidad en agua de agregados en seis suelos con diversos niveles de salinidad y sodicidad (54 dS/m, 11,7%; 49 dS/m, 11,8%; 53 dS/m, 31,7%; 85 dS/m, 39,7%; 59 dS/m, 13,9%; 68 dS/m, 36,8%, respectivamente) y en tres tamaños de agregados (< 1, 1-2, y 2-4 mm). Los experimentos se llevaron a cabo bajo condiciones de laboratorio, usando muestras de suelo disturbadas y no-cosechadas. En suelos con unos altos porcentajes tanto de sodio de cambio como de conductividad eléctrica, el efecto de ciclos hielo-deshielo en la estabilidad en agua de agregados no fue significativo; sin embargo, con una conductividad eléctrica alta y un porcentaje de sodio de cambio relativamente bajo, la estabilidad disminuyó a un nivel significativo. Por otra parte, para los tamaños agregados de 1-2 y 2-4 mm, se observó una disminución significativa (

Dynamic Pricing and Replenishment with Customer Upgrades

We study a joint implementation of price‐ and availability‐based product substitution to better match demand and constrained supply across vertically differentiated products. Our study is motivated by firms that utilize dynamic pricing as well as customer upgrades, as ex ante and ex post mechanisms, respectively, to mitigate inventory mismatches. To gain insight into how offering product upgrades impacts optimal price selection, we formulate a multiple period, nested two‐stage model where the firm first sets prices and replenishment levels for each product while the demand is still uncertain, and after observing the demand, decides how many (if any) of the customers to upgrade to a higher quality product. We characterize the structure of the optimal upgrade, pricing and replenishment policies and find that firms having greater flexibility to offer product upgrades can restrain their reliance on dynamic pricing, enabling them to better protect the price differentiation between the products. We also show how the quality differential between the products or changes in the replenishment cost structures influence the optimal policy. Using insights gained from the optimal policy structure, we construct a heuristic policy and find that it performs well across various parameter values. Finally, we consider an extension in which the firm dynamically sets upgrade fees in each period. Our results overall help further our understanding of the intricate relationship among a firm's decisions on pricing, replenishment, and product upgrades in an effort to better match demand and constrained supply