scholarly journals Predictive CDN Selection for Video Delivery Based on LSTM Network Performance Forecasts and Cost-Effective Trade-Offs

2020 ◽  
pp. 1-14
Author(s):  
Roberto Viola ◽  
Angel Martin ◽  
Javier Morgade ◽  
Stefano Masneri ◽  
Mikel Zorrilla ◽  
...  
2019 ◽  
Vol 12 (5) ◽  
pp. 1093-1102
Author(s):  
Dieter Vanderelst ◽  
Jurgen Willems

AbstractFuture Care Robots (CRs) should be able to balance a patient’s, often conflicting, rights without ongoing supervision. Many of the trade-offs faced by such a robot will require a degree of moral judgment. Some progress has been made on methods to guarantee robots comply with a predefined set of ethical rules. In contrast, methods for selecting these rules are lacking. Approaches departing from existing philosophical frameworks, often do not result in implementable robotic control rules. Machine learning approaches are sensitive to biases in the training data and suffer from opacity. Here, we propose an alternative, empirical, survey-based approach to rule selection. We suggest this approach has several advantages, including transparency and legitimacy. The major challenge for this approach, however, is that a workable solution, or social compromise, has to be found: it must be possible to obtain a consistent and agreed-upon set of rules to govern robotic behavior. In this article, we present an exercise in rule selection for a hypothetical CR to assess the feasibility of our approach. We assume the role of robot developers using a survey to evaluate which robot behavior potential users deem appropriate in a practically relevant setting, i.e., patient non-compliance. We evaluate whether it is possible to find such behaviors through a consensus. Assessing a set of potential robot behaviors, we surveyed the acceptability of robot actions that potentially violate a patient’s autonomy or privacy. Our data support the empirical approach as a promising and cost-effective way to query ethical intuitions, allowing us to select behavior for the hypothetical CR.


2020 ◽  
Vol 2 (7A) ◽  
Author(s):  
Robyn Jerdan ◽  
Scott Cameron ◽  
Emily Donaldson ◽  
Andrew Spiers

Static microcosms are a well-established system used to study the adaptive radiation of Pseudomonas fluorescens SBW25 and the adaptive biofilm-forming mutants known as the Wrinkly Spreaders (WS). We have developed this system to investigate selection within multi-species communities using a soil-wash inoculum dominated by biofilm-competent pseudomonads. Here we present community and isolate-level analyses of one serial-transfer experiment in which replicate populations were selected for over ten transfers and 60 days. Although no significant trends in improving community biofilm characteristics or total microcosm productivity were observed, a significant shift in biofilm-formation and microcosm growth by individual isolates recovered from the initial soil-wash inoculum and final transfers indicated that these communities were subject to selection for growth in these microcosms. Surprisingly, the fitness of the archetypal WS was poor when competing against community samples, and having compared the cell densities in the low-O2 region of liquid column below the biofilm, we suggest that part of the community’s fitness advantage comes from the ability to colonise this under-utilised niche as well as to compete at the A-L interface. Samples from the community biofilms and the low-O2 region were able to re-colonize both niches and many final transfer isolates grew throughout the liquid column as well as forming A-L interface biofilms. This suggests that there is a trade-off between fast growth under highly competitive conditions at the A-L interface and slower growth with less competition in the low-O2 region, with some isolates taking a bet-hedging approach a colonizing both niches in our microcosm system.


2009 ◽  
Vol 10 (04) ◽  
pp. 435-457
Author(s):  
ATHANASIOS KINALIS ◽  
SOTIRIS NIKOLETSEAS

Motivated by emerging applications, we consider sensor networks where the sensors themselves (not just the sinks) are mobile. Furthermore, we focus on mobility scenarios characterized by heterogeneous, highly changing mobility roles in the network. To capture these high dynamics of diverse sensory motion we propose a novel network parameter, the mobility level, which, although simple and local, quite accurately takes into account both the spatial and speed characteristics of motion. We then propose adaptive data dissemination protocols that use the mobility level estimation to optimize performance, by basically exploiting high mobility (redundant message ferrying) as a cost-effective replacement of flooding, e.g. the sensors tend to dynamically propagate less data in the presence of high mobility, while nodes of high mobility are favored for moving data around. These dissemination schemes are enhanced by a distance-sensitive probabilistic message flooding inhibition mechanism that further reduces communication cost, especially for fast nodes of high mobility level, and as distance to data destination decreases. Our simulation findings demonstrate significant performance gains of our protocols compared to non-adaptive protocols, i.e. adaptation increases the success rate and reduces latency (even by 15%) while at the same time significantly reducing energy dissipation (in most cases by even 40%). Also, our adaptive schemes achieve significantly higher message delivery ratio and satisfactory energy-latency trade-offs when compared to flooding when sensor nodes have limited message queues.


Author(s):  
Cesar A. Cortes-Quiroz ◽  
Alireza Azarbadegan ◽  
Emadaldin Moeendarbary ◽  
Mehrdad Zangeneh

Numerical simulations and an optimization method are used to study the design of a planar T-micromixer with curved-shaped baffles in the mixing channel. The mixing efficiency and the pressure loss in the mixing channel have been evaluated for Reynolds number (Re) in the mixing channel in the range 1 to 250. A Mixing index (Mi) has been defined to quantify the mixing efficiency. Three geometric dimensions: radius of baffle, baffles pitch and height of the channel, are taken as design parameters, whereas the mixing index at the outlet section and the pressure loss in the mixing channel are the performance parameters used to optimize the micromixer geometry. To investigate the effect of design and operation parameters on the device performance, a systematic design and optimization methodology is applied, which combines Computational Fluid Dynamics (CFD) with an optimization strategy that integrates Design of Experiments (DOE), Surrogate modeling (SM) and Multi-Objective Genetic Algorithm (MOGA) techniques. The Pareto front of designs with the optimum trade-offs of mixing index and pressure loss is obtained for different values of Re. The micromixer can enhance mixing using the mechanisms of diffusion (lower Re) and convection (higher Re) to achieve values over 90%, in particular for Re in the order of 100 that has been found the cost-effective level for volume flow. This study applies a systematic procedure for evaluation and optimization of a planar T-mixer with baffles in the channel that promote transversal 3-D flow as well as recirculation secondary flows that enhance mixing.


2018 ◽  
Vol 21 (8) ◽  
pp. 1503-1514 ◽  
Author(s):  
Anna K Farmery ◽  
Gabrielle O’Kane ◽  
Alexandra McManus ◽  
Bridget S Green

AbstractObjectiveEncouraging people to eat more seafood can offer a direct, cost-effective way of improving overall health outcomes. However, dietary recommendations to increase seafood consumption have been criticised following concern over the capacity of the seafood industry to meet increased demand, while maintaining sustainable fish stocks. The current research sought to investigate Australian accredited practising dietitians’ (APD) and public health nutritionists’ (PHN) views on seafood sustainability and their dietary recommendations, to identify ways to better align nutrition and sustainability goals.DesignA self-administered online questionnaire exploring seafood consumption advice, perceptions of seafood sustainability and information sources of APD and PHN. Qualitative and quantitative data were collected via open and closed questions. Quantitative data were analysed with χ2 tests and reported using descriptive statistics. Content analysis was used for qualitative data.SettingAustralia.SubjectsAPD and PHN were targeted to participate; the sample includes respondents from urban and regional areas throughout Australia.ResultsResults indicate confusion around the concept of seafood sustainability and where to obtain information, which may limit health professionals’ ability to recommend the best types of seafood to maximise health and sustainability outcomes. Respondents demonstrated limited understanding of seafood sustainability, with 7·5 % (n 6/80) satisfied with their level of understanding.ConclusionsNutrition and sustainability goals can be better aligned by increasing awareness on seafood that is healthy and sustainable. For health professionals to confidently make recommendations, or identify trade-offs, more evidence-based information needs to be made accessible through forums such as dietetic organisations, industry groups and nutrition programmes.


Author(s):  
Satyakiran Munaga ◽  
Francky Catthoor

Modern cost-conscious dynamic systems incorporate knobs that allow run-time trade-offs between system metrics of interest. In these systems regular knob tuning to minimize costs while satisfying hard system constraints is an important aspect. Knob tuning is a combinatorial constrained nonlinear dynamic optimization problem with uncertainties and time-linkage. Hiding uncertainties under worst-case bounds, reacting after the fact, optimizing only the present, and applying static greedy heuristics are widely used problem simplification strategies to keep the design complexity and decision overhead low. Applying any of these will result in highly sub-optimal system realizations in the presence of nonlinearities. The more recently introduced System Scenarios methodology can only handle limited form of dynamics and nonlinearities. Existing predictive optimization approaches are far from optimal as they do not fully exploit the predictability of the system at hand. To bridge this gap, the authors propose the combined strategy of dynamic bounding and proactive system conditioning for the predicted likely future. This paper describes systematic principles to design low-overhead controllers for cost-effective hard constraint management. When applied to fine-grain performance scaling mode assignment problem in a video decoder design, proposed concepts resulted in more than 2x energy gains compared to state-of-the-art techniques.


Author(s):  
G Simm ◽  
W S Dingwall ◽  
S V Murphy ◽  
J FitzSimons ◽  
W R Brown

It is likely that returns from lamb production in future will depend, much more than at present, on producing leaner carcasses. There are several short-term changes in management which could produce leaner carcasses. However, In the longer term genetic Improvement, particularly by within-breed selection In terminal sire breeds, is likely to provide permanent, cumulative and cost-effective benefits In carcass composition. In the early 1980s a research project was started at the Edinburgh School of Agriculture, using Suffolk sheep, to examine the genetic potential for Improving carcass composition In terminal sires. The work commenced with an evaluation of techniques for in vivo measurement of carcass composition (Simm, 1987) and derivation of selection indices to incorporate In vivo measurements (Simm and Dingwall, 1989). Since 1985 In vivo measurement and Index selection have been practised In the experimental flock, which now numbers about 220 ewes. This paper reports the interim results of selection.


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