Dimming cellular networks

We propose a novel technique called dimming to improve the energy efficiency of cellular networks by reducing the capacity, services, and energy consumption of cells without turning off the cells. We define three basic methods to dim the network: coverage, frequency, and service dimming. We construct a multi-time period optimization problem to implement frequency dimming and extend it to implement both frequency and service dimming together. We illustrate the ability of dimming techniques to adapt the capacity and network services in proportion to the dynamic spatial and temporal load resulting in significant energy savings through numerical results for a sample network. ©2010 IEEE

Resource Allocation for Heterogeneous Traffic in LTE Virtual Networks

Cellular network virtualization is being considered as a key trend in future mobile networks towards improved resource utilization. However, virtualization scenarios need investigation to understand the considerations which should be taken into account when deploying virtualized wireless networks in practice. Towards this, we address the performance of a virtualized network in the presence of heterogeneous classes of traffic. In previous cellular network virtualization literature, both Real time (RT) and Non-Real time (NRT) traffic requests have been included without distinction. Both types are provisioned using the same algorithm for allocation of resources specified by the Network Scheduler [1]. However, different types of traffic have different characteristics [2], e.g., RT requests are delay sensitive but may need fixed bandwidth, and hence should be treated differently, especially when wireless channel conditions are factored into the scheduling. We recognize this difference and in this paper, we propose a new approach to improve scheduling of resources for RT and NRT traffic. In particular, we prioritize the traffic belonging to different virtual slices from all service providers (SP/VEs) at the Network Scheduler before allocating resources to different SP/VEs, i.e., We form a Virtual Prioritized Slice (VPS). The virtual prioritized slice is forwarded to the VPS scheduler to serve all RT requests first. Only after the RT traffic is scheduled, the NRT traffic is provisioned using proportional fairness (PF) scheduling. We show by simulation results that this new VPS approach helps outperform recently proposed resource allocation schemes

Modeling and simulation of wireless link quality (ETT) through principal component analysis of trace data

Principal Component Analysis (PCA) is a powerful method in data analysis. In this paper, we employ the capabilities of PCA combined with statistical fits to trace data to develop tractable models that can be used to simulate the quality of links in wireless mesh networks using the expected transmission time (ETT) metric. We apply principal component analysis to ETT traces from a wireless mesh network to determine what features in the ETT traces are important and to extract any meaningful relationships therein. We demonstrate that PCA can be used to efficiently approximate large volumes of ETT values. In particular, the ETT trace for each link can be expressed as a combination of two basis vectors - one fairly stable and the other containing the variations in time. We also show how the extracted features can be employed to simulate ETT for a given network topology with and without known ETT trace data. Copyright 2011 ACM

Mg isotope systematics during magmatic processes: Inter-mineral fractionation in mafic to ultramafic Hawaiian xenoliths

© 2018 Elsevier Ltd Observed differences in Mg isotope ratios between bulk magmatic rocks are small, often on a sub per mill level. Inter–mineral differences in the 26Mg/24Mg ratio (expressed as δ26Mg) in plutonic rocks are on a similar scale, and have mostly been attributed to equilibrium isotope fractionation at magmatic temperatures. Here we report Mg isotope data on minerals in spinel peridotite and garnet pyroxenite xenoliths from the rejuvenated stage of volcanism on Oahu and Kauai, Hawaii. The new data are compared to literature data and to theoretical predictions to investigate the processes responsible for inter–mineral Mg isotope fractionation at magmatic temperatures. Theory predicts up to per mill level differences in δ26Mg between olivine and spinel at magmatic temperatures and a general decrease in Δ26Mgolivine-spinel (=δ26Mgolivine – δ26Mgspinel) with increasing temperature, but also with increasing Cr# in spinel. For peridotites with a simple petrogenetic history by melt depletion, where increasing depletion relates to increasing melting temperatures, Δ26Mgolivine-spinel should thus systematically decrease with increasing Cr# in spinel. However, most natural peridotites, including the Hawaiian spinel peridotites investigated in this study, are overprinted by variable extents of melt-rock reaction, which disturb the systematic primary temperature and compositionally related olivine–spinel Mg isotope systematics. Diffusion, subsolidus re-equilibration, or surface alteration may further affect the observed olivine–spinel Mg isotope fractionation in peridotites, making Δ26Mgolivine-spinel in peridotites a difficult–to–apply geothermometer. The available Mg isotope data on clinopyroxene and garnet suggest that this mineral pair is a more promising geothermometer, but its application is restricted to garnet–bearing igneous (garnet pyroxenites) and metamorphic rocks (eclogites). Although the observed δ26Mg variation is on a sub per mill range in bulk magmatic rocks, the clearly resolvable inter–mineral Mg isotope differences imply that crystallization or preferential melting of isotopically distinct minerals such garnet, spinel, and clinopyroxene should cause Mg isotope fractionation between bulk melt and residue. Calculated Mg isotope variations during partial mantle melting indeed predict differences between melt and residue, but these are analytically resolvable only for melting of mafic lithologies, that is, garnet pyroxenites. Contributions from garnet pyroxenite melts may thus account for some of the isotopically light δ26Mg observed in ocean island basalts and trace lithological mantle heterogeneity. Consequently, applications for high-temperature Mg isotope fractionations are promising and diverse, and recent advances in analytical precision may allow the full petrogenetic potential inherent in the sub per mill variations in δ26Mg in magmatic rocks to be exploited

On Security and reliability using cooperative transmissions in sensor networks

Cooperative transmissions have received recent attention and research papers have demonstrated their benefits for wireless networks. Such benefits include improving the reliability of links through diversity and/or increasing the reach of a link compared to a single transmitter transmitting to a single receiver (single-input single-output or SISO). In one form of cooperative transmissions, multiple nodes can act as virtual antenna elements and provide diversity gain or range improvement using space-time coding. In a multi-hop ad hoc or sensor network, a source node can make use of its neighbors as relays with itself to reach an intermediate node with greater reliability or at a larger distance than otherwise possible. The intermediate node will use its neighbors in a similar manner and this process continues till the destination is reached. Thus, for the same reliability of a link as SISO, the number of hops between a source and destination may be reduced using cooperative transmissions as each hop spans a larger distance. However, the presence of ma-licious or compromised nodes in the network impacts the benefits obtained with cooperative transmissions. Using more relays can increase the reach of a link, but if one or more relays are malicious, the transmission may fail. However, the relationships between the number of relays, the number of hops, and success probabilities are not trivial to determine. In this paper, we analyze this problem to understand the conditions under which cooperative transmissions fare better or worse than SISO transmissions. We take into consideration additional parameters such as the path-loss exponent and provide a framework that allows us to evaluate the conditions when cooperative transmissions are better than SISO transmissions. This analysis provides insights that can be employed before resorting to simulations or experimentation. © Springer Science+Business Media, LLC 2012

Predictive person models elicit motor biases: The face-inhibition effect revisited

Using an established paradigm, we tested whether people derive motoric predictions about an actor’s forthcoming actions from prior knowledge about them and the context in which they are seen. In two experiments, participants identified famous tennis and soccer players using either hand or foot responses. Athletes were shown either carrying out or not carrying out their associated actions (swinging, kicking), either in the context where these actions are typically seen (tennis court, soccer Pitch) or outside these contexts (beach, awards ceremony). Replicating prior work, identifying non-acting athletes revealed the negative compatibility effects: viewing tennis players led to faster responses with a foot than a hand, and vice versa for viewing soccer players. Consistent with the idea that negative compatibility effects result from the absence of a predicted action, these effects were eliminated (or reversed) when the athletes were seen carrying out actions typically associated with them. Strikingly, however, these motoric biases were not limited to In-Context trials but were, if anything, more robust in the Out-of-Context trials. This pattern held even when attention was drawn specifically to the context (Experiment 2). These results confirm that people hold motoric knowledge about the actions that others typically carry out and that these actions are part of perceptual representations that are accessed when those others are re-encountered, possibly in order to resolve uncertainty in person perception

Gaze cueing and affective judgments of objects: I like what you look at

When we see another person look somewhere, we automatically attend to the same location in space. This joint attention emerges early in life and has a great impact on social interactions in development and in everyday adult life. The direction of another's gaze indicates what object is of current interest, which may be the target for a subsequent action. In this study, we found that objects that are looked at by other people are liked more than objects that do not receive the attention of other people (Experiment 1). This suggests that observing averted gaze can have an impact on the affective appraisals of objects in the environment. This liking effect was absent when an arrow was used to cue attention (Experiment 2). This underlines the importance of other people's interactions with objects for generating our own impressions of such stimuli in the world

Influence of hand position on the near-effect in 3D attention

Voluntary reorienting of attention in real depth situations is characterized by an attentional bias to locations near the viewer once attention is deployed to a spatially cued object in depth. Previously this effect (initially referred to as the ‘near-effect’) was attributed to access of a 3D viewer-centred spatial representation for guiding attention in 3D space. The aim of this study was to investigate whether the near-bias could have been associated with the position of the response-hand, always near the viewer in previous studies investigating endogenous attentional shifts in real depth. In Experiment 1, the response-hand was placed at either the near or far target depth in a depth cueing task. Placing the response-hand at the far target depth abolished the near-effect, but failed to bias spatial attention to the far location. Experiment 2 showed that the response-hand effect was not modulated by the presence of an additional passive hand, whereas Experiment 3 confirmed that attentional prioritization of the passive hand was not masked by the influence of the responding hand on spatial attention in Experiment 2. The pattern of results is most consistent with the idea that response preparation can modulate spatial attention within a 3D viewer-centred spatial representation

Translation of the L-species dsRNA genome of the killer-associated virus-like particles of Saccharomyces cerevisiae

Virus-like particles containing the L (P1)-species of double-stranded RNA (dsRNA) were isolated from Saccharomyces cerevisiae, and the translational activity of the virus-like particle-derived dsRNA was analyzed in the wheat germ cell-free system. Denaturation of the dsRNA immediately prior to in vitro translation resulted in the synthesis of one major and at least three minor polypeptides, whereas undenatured dsRNA, as expected, did not stimulate [35S]methionine incorporation into polypeptides, but actually slightly inhibited endogenous activity. The major in vitro translation product of the denatured L-dsRNA was shown to be identical with the major L-dsRNA containing virus-like particle capsid polypeptide on the basis of three criteria: co-electrophoresis on sodium dodecyl sulfate polyacrylamide gels, immunoprecipitation, and tryptic peptide analysis. We have therefore established that the L-dsRNA genome encodes the major virus-like particle capsid polypeptide. This result adds considerable support to the hypothesis that the L-dsRNA genome acts as a helper genome to the smaller (1.6 x 10(6) dalton) M-dsRNA genome in killer strains of yeast by providing the M-dsRNA containing virus-like particles with their major coat protein