Efficient and scalable continuous skyline monitoring in two-tier streaming settings

Two-tier streaming settings are a typical dynamic environment where continuous skylines represent an important semantic indicator for multiple attributes. To monitor skylines over the dynamic data in such settings, one needs to continuously update the skyline query results in order to reflect the new data values. This paper tackles the problem of continuous skyline monitoring on a central query server over dynamic data from multiple data sites. Simply sending the updates of tuple values to the server is cost-prohibitive. Therefore, we propose an approach that allows the central server to collaborate with the data sites to monitor the possible skyline changes. By doing so, the processing load is distributed over all the data sites instead of only on the central server. Furthermore, this collaborative approach minimizes the bandwidth consumption between the server and the data sites, which is often critical in a widely distributed environment such as a wide-area sensor network. We give theoretical upper bounds for the computation costs and communication costs of the proposed collaborative approach. We also conduct extensive experiments on both synthetic and real data sets. The experimental results demonstrate that our collaborative approach is efficient, scalable and well-balanced in terms of communication costs and computation costs.     

Coordination-based inventory management for deteriorating items in a two-echelon supply chain with profit sharing

This study develops a model for inventory management consisting of a two-echelon supply chain (SC) with profit sharing and deteriorating items. The retailer and the supplier act as the leader and follower, in which the supplier faces a huge setup cost and economic order quantity ordering strategy. The market demand is affected by the sale price of the product, and the inventory has a deterioration rate following a Weibull distribution. The retailer executes three profit-sharing mechanisms to motivate the supplier to participate in SC optimisation and to extend the life cycle of the product. A search algorithm is developed to determine the solutions as using the profit-sharing mechanisms. The outcomes from numerical experiments demonstrate the profitability of the proposed model.     

Emotional labor, strain, and performance: Testing reciprocal relationships in a longitudinal panel study.

Models of emotional labor suggest that emotional labor leads to strain and affects job performance. Although the link between emotional labor, strain, and performance has been well documented in cross-sectional field studies, not much is known about the causal direction of relationships between emotional labor, strain, and performance. Goal of the present study was therefore to test the direction of effects in a two-wave longitudinal panel study using a sample of 151 trainee teachers. Longitudinal lagged effects were tested using structural equation modeling. Results revealed that the emotional labor strategy of surface acting led to increases in subsequent strain while deep acting led to increases in job performance. In contrast, there was no indication of reverse causation: Neither strain nor job performance had a significant lagged effect on subsequent surface or deep acting. Overall, results support models of emotional labor suggesting that surface and deep acting causally precede individual and organizational well-being. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Avrami kinetics of dynamic recrystallization

Twenty-six flow curves determined under dynamic recrystallization (DRX) conditions on 11 different steels were analyzed. The double-differentiation method was used to define the critical strain ε_c for initiation of DRX. The “athermal” hardening parameter h and the dynamic recovery parameter r were evaluated from the work-hardening behavior prior to ε_c. The saturation stresses σ_sat pertaining to the unrecrystallized regions as well as the associated work-hardening curves, σ_recov, were derived in this way. The net softening attributable to DRX was then defined as the difference between the σ_recov and experimental curves. Avrami plots were prepared from all 26 sets of data. The time exponents were all in the neighborhood of 3.0; however, the strain rate and temperature dependences differed considerably from their static values. The dependence of the time of half-softening, t₅₀, on strain rate and temperature is used to predict the DRX curves expected under industrial conditions.     

Scalable production of graphene sheets by mechanical delamination

Mono- and multilayer graphene sheets have been successfully produced from commercial graphite powder in a wet grinding process under mild milling conditions. The shear forces in the milling chamber lead to a continuous delamination of ultrathin graphene flakes which are dispersed in a liquid medium. To avoid agglomeration of the exfoliated flakes the anionic surfactant sodium dodecyl sulfate was used. By adjusting the process parameters in a way to overcome the weak interlayer forces between the sheets without breaking them leads to the fabrication of thin flakes with high aspect ratios. The presented scalable process allows a high-yield and low-cost production of free-standing graphene sheets for various applications.     

An Adaptive Contact Model for the Robust Simulation of Knots

In this paper, we present an adaptive model for dynamically deforming hyper‐elastic rods. In contrast to existing approaches, adaptively introduced control points are not governed by geometric subdivision rules. Instead, their states are determined by employing a non‐linear energy‐minimization approach. Since valid control points are computed instantaneously, post‐stabilization schemes are avoided and the stability of the dynamic simulation is improved. Due to inherently complex contact configurations, the simulation of knot tying using rods is a challenging task. In order to address this problem, we combine our adaptive model with a robust and accurate collision handling method for elastic rods. By employing our scheme, complex knot configurations can be simulated in a physically plausible way.     

Human fear conditioning is related to dopaminergic and serotonergic biological markers.

Biological markers for acquisition and extinction of fear conditioning were studied in 40 individuals selected for displaying either good or poor acquisiton of fear conditioning, as estimated by the skin conductance response. Participants with a short serotonin transporter (5-HTT) promoter allele or low monoamine oxidase activity in platelets (trbc-MAO) displayed better acquisition than those with only long alleles or high trbc-MAO, whereas participants with a long dopamine D4 receptor (D4DR) exon III allele showed delayed extinction compared with those with only short alleles. The findings, that D4DR exon III and 5-HTT promotor genotypes and trbc-MAO activity are related to human fear conditioning, a basic form of associative learning, are consistent with animal studies suggesting a genetic contribution to fear conditioning. The authors suggest that in humans these genetic mechanisms are partly dopaminergic and serotonergic in origin. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

New Jersey Acts on Energy and Climate Change [Living with Technology]

An unusual aspect of this conference was its focus on state-level energy and climate policies. The lack of federal leadership on these issues within the U.S.A. has opened a window of opportunity at the state level for policy entrepreneurs. California acted in 2005 with an executive order establishing greenhouse gas emission reduction targets, ratified in 2006 by the state legislature. New Jersey acted in 2007, helped along by the fact-finding, target-setting effort leading to this conference. The thoughtful discussions and careful analysis that played out during 2006 and early 2007 played a role in giving policymakers and stake holders the confidence to act decisively. Thus, by February 2007, New Jersey's governor had penned an executive order setting two greenhouse gas targets: reduce emissions to 1990 levels by 2020, and reduce emissions to 80% below current levels by 2050.     

No security: A meta-analysis and review of job insecurity and its consequences.

Meta-analytic techniques were used to estimate how job insecurity relates to its postulated outcomes. Consistent with the conceptual framework, the results indicate that job insecurity has detrimental consequences for employees' job attitudes, organizational attitudes, health, and, to some extent, their behavioral relationship with the organization. Moderator analyses suggest that these relationships may be underestimated in studies relying on single-item measures of job insecurity and that the behavioral consequences of insecurity are more detrimental among manual, as compared with nonmanual, workers. Recommendations made for future research include utilization of multidimensional measures, consideration of a broader spectrum of outcomes and moderators, and use of longitudinal designs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)