Resilience options for provisioning anycast cloud services with virtual optical networks

Optical networks are crucial to support increasingly demanding cloud services. Delivering the requested quality of services (in particular latency) is key to successfully provisioning end-to-end services in clouds. Therefore, as for traditional optical network services, it is of utter importance to guarantee that clouds are resilient to any failure of either network infrastructure (links and/or nodes) or data centers. A crucial concept in establishing cloud services is that of network virtualization: the physical infrastructure is logically partitioned in separate virtual networks. To guarantee end-to-end resilience for cloud services in such a set-up, we need to simultaneously route the services and map the virtual network, in such a way that an alternate routing in case of physical resource failures is always available. Note that combined control of the network and data center resources is exploited, and the anycast routing concept applies: we can choose the data center to provide server resources requested by the customer to optimize resource usage and/or resiliency. This paper investigates the design of scalable optimization models to perform the virtual network mapping resiliently. We compare various resilience options, and analyze their compromise between bandwidth requirements and resiliency quality

Scalable algorithms for QoS-aware virtual network mapping for cloud services

Both business and consumer applications increasingly depend on cloud solutions. Yet, many are still reluctant to move to cloud-based solutions, mainly due to concerns of service quality and reliability. Since cloud platforms depend both on IT resources (located in data centers, DCs) and network infrastructure connecting to it, both QoS and resilience should be offered with end-to-end guarantees up to and including the server resources. The latter currently is largely impeded by the fact that the network and cloud DC domains are typically operated by disjoint entities. Network virtualization, together with combined control of network and IT resources can solve that problem. Here, we formally state the combined network and IT provisioning problem for a set of virtual networks, incorporating resilience as well as QoS in physical and virtual layers. We provide a scalable column generation model, to address real world network sizes. We analyze the latter in extensive case studies, to answer the question at which layer to provision QoS and resilience in virtual networks for cloud services

A Risk-focused Performance Management System Framework for Planning Change in Organisations: New Zealand 'Gentailers' and the ETS

In 2007 the New Zealand government in principle adopted the implementation of a cap and trade emissions trading scheme (ETS) in the energy sector from 2010. The objective of this paper is to develop a risk-focused performance management system (PMS) planning framework for organisations undergoing externally-driven regulatory change that constrains their operating environment and increases business and operating risk exposure. This paper focuses on the New Zealand electricity generators and retailers (gentailers). It utilises contingency theory and secondary data to explain PMS change implications due to the altered business risk exposure potential of the proposed emissions trading regime and the associated carbon constraints this regulatory change imposes on these organisations' operating environment. The risk-focused PMS planning framework developed in this study allowed the identification of the drivers and attributes that due to the ETS adoption potentially have significant negative business risk impacts for some gentailers. The findings arising from the application of this risk-focused PMS framework to the New Zealand electricity gentailers suggest that the predominantly thermal-based generators will be more disadvantaged due to a reduction in competitiveness and profitability. This reduction is the result of the interaction between the ETS-related risks and the sources and types of external and internal environmental uncertainty associated with the regulatory change. The business risks identified not only influence organisational-level PMS design function and operation needs but also have economic consequences at sectoral and national levels particularly in relation to national security of electricity supply. The paper provides insights into an organisation's potential internal adjustments in response to increases in internal and external business risks due to the introduction of the ETS and changing wider environmental management expectations. Theory implications relate to the role and use of risk in improving the application of contingency theory in explaining organisational change under environmental pressures. Additionally the paper contributes to the management accounting research through the examination of the internalisation of externalities such as wider climate change management. Consequently the findings of this study will be of potential interest to academics managers accountants other professionals governments and policy-makers

Uncertainty, MCS and Firm Performance: Towards an Integrated Business Risk Focused Framework

Uncertainty is the core variable in any contingency theoretical framework (Chapman, 1997; Donaldson, 2001). Many reviews however have claimed that the accounting literature lacks a comprehensive framework for analysis of the relationship between uncertainty and MCS (Otley, 1980; Dent, 1990; Chapman, 1997; Langfield-Smith, 1997, Chenhall, 2003). Central to this study is the specification of uncertainty as it has been applied in contingency-based MCS research. This study argues that uncertainty, whilst well specified in terms of sources and types, it is under (not sufficiently) specified in terms of determining the degrees of uncertainty. This limitation is argued to impact on the explanatory and predictive capacity of an MCS based contingency theory (Schoonhoven, 1981). A theoretical framework is developed drawing insights from Otley (1999) and Kaufman (1992) that adopts a business risk view of uncertainty to explain or predict MCS fit/misfit with firm objectives, strategies and operational activities. It is postulated that the degree of change in business risk will signal and influence the level of required changes in MCS design and/or use and go toward addressing the under-specification of ‘degrees of uncertainty’. The level, extent and form of actual changes are dependent on firm capacity, defined as the available and accessible human and non-human resources, to realize the required changes. In doing so, along with considering the equilibrium/fit issues raised by Hartman and Moers (1999), the framework provides a potential basis for reviewing the apparent inconsistencies of past MCS research, and for positioning those studies argued to be narrow and/or of incomparable research design (Otley, 1981; Chapman, 1997). More importantly, a methodology for identifying external and internal drivers of uncertainty from a business risk perspective is presented. Additionally, through such identification a potentially proactive signalling mechanism for changes to MCS design and/or use is provided. The analytical findings of this paper will be of interest to managers, industry professionals, practitioners and academics alike

Anycast end-to-end resilience for cloud services over virtual optical networks

Optical networks are crucial to support increasingly demanding cloud services. Delivering the requested quality of service is key to successfully provisioning end-to-end services in clouds. Therefore, as for traditional optical network services, it is of utter importance to guarantee that clouds are resilient to any failure of either network infrastructure or data centers. A crucial concept in establishing cloud services is that of network virtualization: the physical infrastructure is logically partitioned in separate virtual networks. Also, combined control of the network and data center (IT) resources is exploited. To guarantee end-to-end resilience for cloud services in such a set-up, we need to simultaneously route the services and map the virtual network, while ensuring that an alternate routing is always available. Note that the anycast routing concept applies: assigning server resources requested by the customer to a particular (physical) data center can be done transparently. This paper investigates the design of scalable optimization models to perform the virtual network mapping resiliently (for single bidirectional link failures), thus supporting resilient anycast cloud virtual networks. We compare two resilience approaches: PIP-resilience maps each virtual link to two alternate physical routes, VNO-resilience provides alternate paths in the virtual topology (while enforcing physical link disjointness)

Mars methane engine

The feasibility of an internal combustion engine operating on a mixture of methane, carbon dioxide, and oxygen has been verified by previous design groups for the Mars Methane Engine Project. Preliminary stoichiometric calculations examined the theoretical fuel-air ratios needed for the combustion of methane. Installation of a computer data acquisition system along with various ancillary components will enable the performance of the engine, running on the described methane mixture, to be optimized with respect to minimizing excess fuel. Theoretical calculations for stoichiometric combustion of methane-oxygen-carbon dioxide mixtures yielded a ratio of 1:2:4.79 for a methane-oxygen-carbon dioxide mixture. Empirical data shows the values to be closer to 1:2.33:3.69 for optimum operation

Time-varying resilient virtual network mapping for multi-location cloud data centers

Optical networks constitute a fundamental building block that has enabled the success of cloud computing. Virtualization, a cornerstone of cloud computing, today is applied in the networking field: physical network infrastructure is logically partitioned into separate virtual networks, thus providing isolation between distinct virtual network operators (VNOs). Hence, the problem of virtual network mapping has arisen: how to decide which physical resources to allocate for a particular virtual network? In a cloud context, not just network connectivity is required, but also data center (DC) resources located at multiple locations, for computation and/or storage. Given the underlying anycast routing principle, the network operator has some freedom to which specific DC to allocate these resources. In this paper, we solve a resilient virtual network mapping problem that optimally decides on the mapping of both network and multi-location data center resources resiliently using anycast routing, considering time-varying traffic conditions. In terms of resilience, we consider the so-called VNO-resilience scheme, where resilience is provided in the virtual network layer. To minimize physical resource capacity requirements, we allow reuse of both network and DC resources. The failures we protect against include both network and DC resource failures: we hence allocate backup DC resources, and also account for synchronization between primary and backup DC. As optimization criteria, we not only consider resource usage minimization, but also aim to limit virtual network reconfigurations from one time period to the next. We propose a scalable column generation approach to solve the dynamic resilient virtual network mapping problem, and demonstrate it in a case study on a nationwide US backbone network

NASA Armstrong's Approach to Store Separation Analysis

Presentation will an overview of NASA Armstrong's store separation capabilities and how they have been applied recently. Objective of the presentation is to brief Generation Orbit and other potential partners on NASA Armstrong's store separation capabilities. It will include discussions on the use of NAVSEP and Cart3D, as well as some Python scripting work to perform the analysis, and a short overview of this methodology applied to the Towed Glider Air Launch System. Collaboration with potential customers in this area could lead to funding for the further development of a store separation capability at NASA Armstrong, which would boost the portfolio of engineering expertise at the center

Optimal control and real-time simulation of hybrid marine power plants

With significantly increasing concerns about greenhouse effects and sustainable economy, the marine industry presents great potential for reducing its environmental impact. Recent developments in power electronics and hybridisation technologies create new opportunities for innovative marine power plants which utilize both traditional diesel generators and energy storage like batteries and/or supercapacitors as the power sources. However, power management of such complex systems in order to achieve the best efficiency becomes one of the major challenges. Acknowledging this importance, this research aims to develop an optimal control strategy (OCS) for hybrid marine power plants. First, architecture of the researched marine power plant is briefly discussed and a simple plant model is presented. The generator can be used to charge the batteries when the ship works with low power demands. Conversely, this battery energy can be used as an additional power source to drive the propulsion or assist the generators when necessary. In addition, energy losses through braking can be recuperated and stored in the battery for later use. Second, the OCS is developed based on equivalent fuel consumption minimisation (EFCM) approach to manage efficiently the power flow between the power sources. This helps the generators to work at the optimal operating conditions, conserving fuel and lowering emissions. In principle, the EFCM is based on the simple concept that discharging the battery at present is equivalent to a fuel burn in the future and vice-versa and, is suitable for real-time implementation. However, instantaneously regulating the power sources’ demands could affect the system stability as well as the lifetime of the components. To overcome this drawback and to achieve smooth energy management, the OCS is designed with a number of penalty factors by considering carefully the system states, such as generators’ fuel consumption and dynamics (stop/start and cranking behaviour), battery state of charge and power demands. Moreover, adaptive energy conversion factors are designed using artificial intelligence and integrated in the OCS design to improve the management performance. The system therefore is capable of operating in the highest fuel economy zone and without sacrificing the overall performance. Furthermore, a real-time simulation platform has been developed for the future investigation of the control logic. The effectiveness of the proposed OCS is then verified through numerical simulations with a number of test cases

A Risk-focused Performance Management System Framework for Planning Change in Organisations: New Zealand 'Gentailers' and the ETS

In 2007 the New Zealand government in principle adopted the implementation of a cap and trade emissions trading scheme (ETS) in the energy sector from 2010. The objective of this paper is to develop a risk-focused performance management system (PMS) planning framework for organisations undergoing externally-driven regulatory change that constrains their operating environment and increases business and operating risk exposure. This paper focuses on the New Zealand electricity generators and retailers (gentailers). It utilises contingency theory and secondary data to explain PMS change implications due to the altered business risk exposure potential of the proposed emissions trading regime and the associated carbon constraints this regulatory change imposes on these organisations' operating environment. The risk-focused PMS planning framework developed in this study allowed the identification of the drivers and attributes that due to the ETS adoption potentially have significant negative business risk impacts for some gentailers. The findings arising from the application of this risk-focused PMS framework to the New Zealand electricity gentailers suggest that the predominantly thermal-based generators will be more disadvantaged due to a reduction in competitiveness and profitability. This reduction is the result of the interaction between the ETS-related risks and the sources and types of external and internal environmental uncertainty associated with the regulatory change. The business risks identified not only influence organisational-level PMS design function and operation needs but also have economic consequences at sectoral and national levels particularly in relation to national security of electricity supply. The paper provides insights into an organisation's potential internal adjustments in response to increases in internal and external business risks due to the introduction of the ETS and changing wider environmental management expectations. Theory implications relate to the role and use of risk in improving the application of contingency theory in explaining organisational change under environmental pressures. Additionally the paper contributes to the management accounting research through the examination of the internalisation of externalities such as wider climate change management. Consequently the findings of this study will be of potential interest to academics managers accountants other professionals governments and policy-makers