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12.
Data centers, as resource providers, are expected to deliver on performance guarantees while optimizing resource utilization
to reduce cost. Virtualization techniques provide the opportunity of consolidating multiple separately managed containers
of virtual resources on underutilized physical servers. A key challenge that comes with virtualization is the simultaneous
on-demand provisioning of shared physical resources to virtual containers and the management of their capacities to meet service-quality
targets at the least cost. This paper proposes a two-level resource management system to dynamically allocate resources to
individual virtual containers. It uses local controllers at the virtual-container level and a global controller at the resource-pool
level. An important advantage of this two-level control architecture is that it allows independent controller designs for
separately optimizing the performance of applications and the use of resources. Autonomic resource allocation is realized
through the interaction of the local and global controllers. A novelty of the local controller designs is their use of fuzzy
logic-based approaches to efficiently and robustly deal with the complexity and uncertainties of dynamically changing workloads
and resource usage. The global controller determines the resource allocation based on a proposed profit model, with the goal
of maximizing the total profit of the data center. Experimental results obtained through a prototype implementation demonstrate
that, for the scenarios under consideration, the proposed resource management system can significantly reduce resource consumption
while still achieving application performance targets.
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13.
This article proposes a linear programming model that is based on the wastewater treatment input‐output model (W 2IO) to identify the lowest‐emission choice among alternative feasible options for wastewater treatment; this model can be considered as an application of the waste input‐output linear programming model (WIO‐LP) to wastewater issues. Using the data of the Tokyo metropolitan W 2IO table, I apply this model to obtain the optimal wastewater treatment options under alternative scenarios. The Pareto frontiers of environmental loads are derived to show the trade‐off relationships among various types of environmental load and the effect of the introduction of high‐temperature incineration of dewatered sludge on the generation of environmental loads. The main conclusion of the study is that when all three types of environmental load (landfill level, global warming potential, and chemical oxygen demand) are considered, the introduction of high‐temperature incineration causes the widening of the Pareto frontier of environmental loads and also causes it to move closer to the origin. 相似文献
14.
Invasive species can cause severe damage in their introduced range; this damage often persists even after removal of the invader. In order to efficiently allocate a limited budget between invader removal and restoration of habitat from which the invader has been removed, it is vital to quantify the impacts of the invasion within an economic context. Here we develop optimal management strategies for biological invasions, which minimize both the direct economic costs of removal and restoration, and the ecological costs of present and future damage caused by the invasion. We demonstrate how this can be formulated as a linear programming problem, enabling the fast and efficient computation of optimal solutions. Using a simple example, we outline some general principles for the optimal control of an invader that damages its environment. Notably, we show that the most effective strategies often switch the priority of removal and restoration over time, and outline the conditions under which restoration is prioritized over removal. The proportion of total funds allocated to restoration will depend on the annual budget, the persistence of damage, and the relative costs of damage, removal and restoration. 相似文献
15.
Summary The effect is modeled of a positive relationship between clutch size and offspring fitness on the optimal investment in offspring. In species which meet the assumptions of the model, the model predicts a positive correlation between maternal resource level and offspring size. If larger mothers are able to allocate more resources to offspring, then the model would also predict a positive correlation between maternal size and offspring size when the assumptions of the model are met. Thus, this model may help explain both among and within individual variation in offspring size. When offspring are produced in groups and the number of offspring killed per clutch is limited by predator satiation, offspring in larger clutches may experience a higher probability of survival. Such a life style may be found in animals such as sea turtles. Offspring size is positively correlated with maternal size in some members of this group. 相似文献
16.
The expense of traditional capture‐recapture methods, interest in less invasive survey methods, and the circumpolar decline of polar bear ( Ursus maritimus) habitat require evaluation of alternative methods for monitoring polar bear populations. Aerial line transect distance sampling (DS) surveys are thought to be a promising monitoring tool. However, low densities and few observations during a survey can result in low precision, and logistical constraints such as heavy ice and fuel and safety limitations may restrict survey coverage. We used simulations to investigate the accuracy and precision of, DS for estimating polar bear abundance in sea ice habitats, using the Chukchi Sea subpopulation as an example. Simulation parameters were informed from a recent pilot survey. Predictions from a resource selection model were used for stratification, and we compared two ratio estimators to account for areas that cannot be sampled. The ratio estimator using predictions of resource selection by polar bears allowed for extrapolation beyond sampled areas and provided results with low bias and CVs ranging from 21% to 36% when abundance was >1,000. These techniques could be applied to other DS surveys to allocate effort and potentially extrapolate estimates to include portions of the landscape that are logistically impossible to survey. 相似文献
17.
Several proximate factors of masting have been provided. Here, I focus on the role of internal factors, especially the relationship between internal carbon resources and modular structures in trees. I summarize various studies of carbon resource allocation for reproduction during masting events in terms of the proximate factors of masting and discuss the modular structure in which trees accumulate and consume carbon resources as well as the timing when internal carbon resources affect masting since trees have complex resource dynamics among organs. The resource budget model, which provides a simple mechanistic explanation of the masting mechanism, is supported by various study lines. This model assumes decreasing levels of stored photosynthate after flowering and fruiting. According to several studies, however, carbon reserves do not decrease after fruiting in species in which the modules autonomously allocate current photosynthate for fruiting. In addition, it is important to elucidate when carbon resources affect masting events because during their long developmental processes, trees pass through various stages until they produce maturing fruits to create successful masting events. To explore the mechanisms of masting in future studies, it would be important to figure out how and when candidate factors (including nutrients other than carbon) may influence the entire reproduction process, for example, using field manipulation experiments. 相似文献
18.
The problem of invasive species and their control is one of the most pressing applied issues in ecology today. We developed simple approaches based on linear programming for determining the optimal removal strategies of different stage or age classes for control of invasive species that are still in a density-independent phase of growth. We illustrate the application of this method to the specific example of invasive Spartina alterniflora in Willapa Bay, WA. For all such systems, linear programming shows in general that the optimal strategy in any time step is to prioritize removal of a single age or stage class. The optimal strategy adjusts which class is the focus of control through time and can be much more cost effective than prioritizing removal of the same stage class each year. 相似文献
19.
In this paper we present a scheduling strategy for workstation clusters able to effectively and fairly schedule general-purpose workloads potentially made up by compute-bound, interactive, and I/O-intensive applications, that may each be sequential, client-server, or parallel. The scheduling strategy allocates resources to processes of the same parallel applications in such a way that they all get the same CPU share regardless of the level of resource contention on the respective machines, and relies on an extended stride scheduler to fairly allocate individual workstations. A simulation analysis carried out for a variety of workloads and operational conditions shows that our strategy (a) delivers good performance to all the applications classes composing general-purpose workloads, (b) fairly allocates resources among competing applications, and (c) outperforms alternative strategies. 相似文献
20.
Land use optimization as a resource allocation problem can be defined as the process of assigning different land uses to a region. Sustainable development also involves the exploitation of environmental resources, investment orientation, technology development, and industrial changes in a coordinated form. This paper studies the multi-objective sustainable land use planning problem and proposes an integrated framework, including simulation, forecasting, and optimization approaches for this problem. Land use optimization, a multifaceted process, requires complex decisions, including selection of land uses, forecasting land use allocation percentage, and assigning locations to land uses. The land use allocation percentage in the selected horizons is simulated and predicted by designing a System Dynamics (SD) model based on socio-economic variables. Furthermore, land use assignment is accomplished with a multi-objective integer programming model that is solved using augmented ε-constraint and non-dominated sorting genetic algorithm II (NSGA-II) methods. According to the results of the SD model, land use changes depend on population growth rate and labor productivity variables. Among the possible scenarios, a scenario focusing more on sustainable planning is chosen and the forecasting results of this scenario are used for optimal land use allocation. The computational results show that the augmented ε-constraint method cannot solve this problem even for medium sizes. The NSGA-II method not only solves the problem at large sizes over a reasonable time, but also generates good-quality solutions. NSGA-II showed better performance in metrics, including number of non-dominated Pareto solutions (NNPS), mean ideal distance (MID), and dispersion metric (DM). Integrated framework is implemented to allocate four types of land uses consisting of residential, commercial, industrial, and agricultural to a given region with 900 cells. 相似文献
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