601 research outputs found

    An energy management strategy for plug-in hybrid electric vehicles

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    This dissertation formulates a proposal for a real time implementable energy management strategy (EMS) for plug-in hybrid electric vehicles. The EMS is developed to minimize vehicle fuel consumption through the utilisation of stored electric energy and high-efficiency operation of powertrain components. This objective is achieved through the development of a predictive EMS, which, in addition to fuel efficiency, is optimized in terms of computational cost and drivability. The requirement for an EMS in hybrid powertrain vehicles stems from the integration of two energy stores and converters in the powertrain; in the case of hybrid electric vehicles (HEVs) usually a combustion engine and one or more electric machines powered by a battery. During operation of the vehicle the EMS controls power distribution between engine and electric traction motor. Power distribution is optimized according to the operating point dependent efficiencies of the components, energy level of the battery and trip foreknowledge. Drivability considerations, e.g. frequency of engine starts, can also be considered. Due to high oil prices and legislative requirements caused by the environmental impact of greenhouse emissions, fuel economy has gained importance in recent years. In addition to increased fuel economy, powertrain hybridization permits the substituton of fuel for electrical energy by implementing an external recharging option for the battery. This vehicle class, incorporating a battery rechargeable via the electrical grid, is known as a plug-in HEV (PHEV). PHEV share characteristics of both HEVs and all-electric vehicles combining several advantages of both technologies. The rechargeable battery feature of the PHEVs makes their EMS development espe-cially challenging. For minimal fuel consumption, the battery is discharged optimally over the whole trip length, prioritising electrical energy when driving conditions are such that its use maximises the fuel saving that can be achieved. Therefore, an EMS for a PHEV depends heavily on the availability of a priori knowledge about the trip, i.e. the knowledge about future vehicle speed and road grade. This requires the driver to indi-cate the route before trip start. The route knowledge in combination with GPS or Galileo based next generation navigation systems using information from a geographic in-formation system (GIS) about terrain height profile, road type (e.g. motorway or country road), and legal speed limits can be evaluated by a speed prediction algorithm including information about the driver's behaviour for a detailed prediction of the trip. These navigation systems and algorithms in combination with expected future advances and the deployment of technologies such as intelligent transport systems (ITS) and vehicle-to-vehicle communication (V2V), will make more exact traffic information available to further improve prediction. Despite expected advances in prediction quality, inaccuracy of prediction data has to be considered and is therefore regarded in this work. The EMS proposed in this dissertation combines different approaches which are exe-cuted step by step. A first approximation of the energy distribution during the trip is based on a mixed integer linear program (MILP), which gives the optimal energy state of the battery during the trip. This is especially important for trips with long uphill, downhill or urban phases, i.e. sections with a particularly high or lower power requirement. The results from MILP are then used by a dynamic programming (DP) algorithm to calculate optimal torque and gear using a receding prediction horizon. Using a receding prediction horizon, an important reduction of computational cost is achieved. Lastly, from the DP results a rule-based strategy is extracted using a support vector machine (SVM). This last step is necessary to ensure the drivability of the vehicle also for inaccurate prediction data

    Россия в условиях современной экономической глобализации

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    В статье автор пытается определить содержание глобализации как экономической категории. Рассматривает различные подходы к определению глобализации. Выделяет наиболее характерные признаки глобализации, положительные и отрицательные стороны этого явления. На базе анализа глобализации как экономического явления он пытается сделать выводы для российской экономической политики. Акцентирует внимание на необходимости адекватно реагировать на вызовы мировой капиталистической реальности, обращает внимание на то, что абсолютизация рыночных начал дискредитирует идею глобализации. Делает вывод о необходимости усиления внимания к социальным аспектам и противоречиям глобализации с целью минимизации негативных последствий этого явления

    Other‐Sacrificing Options

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    I argue that you can be permitted to discount the interests of your adversaries even though doing so would be impartially suboptimal. This means that, in addition to the kinds of moral options that the literature traditionally recognises, there exist what I call other-sacrificing options. I explore the idea that you cannot discount the interests of your adversaries as much as you can favour the interests of your intimates; if this is correct, then there is an asymmetry between negative partiality toward your adversaries and positive partiality toward your intimates

    Does what happens abroad stay abroad? Displaced aggression and emotional regulation in expatriate psychological contracts

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    The effects of psychological contract violation are the subject of considerable research. Yet, their effects in work arrangements with more than two parties are largely unknown. Multi‐party work arrangements differ from traditional ones because individuals may be vulnerable to psychological contract breach and violation by more than one party, potentially directing negative emotional responses not only towards the responsible party but also displacing it to the other (innocent) party. Primary data from a two‐wave survey of 221 current expatriates is used to test the effects of displaced aggression and emotion regulation in multi‐party psychological contracts. We find that the negative emotions (violation experiences) associated with breach predict reduced commitment both to the perpetrating organization and the innocent party. However, this spillover effect is asymmetric and follows displaced aggregation theory: Expatriates displace their aggressive behaviour on to the host when the home organization violated the psychological contract, not the reverse

    When Foreign Waves Hit Home Shores: Organizational Identification in Psychological Contract Breach‐Violation Relationships During International Assignments

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    In the context of international assignments, this study investigates the psychological contract breach-violation relationship from a multi-party employment perspective. Multi-party employment refers to arrangements where employees have concurrent psychological contracts with more than one party. Drawing on two-waves of survey data from 221 expatriates, we find both direct relationships and asymmetric spillover effects of psychological contract breach on violation. Psychological contract breach by either the home or host organization is directly linked to psychological contract violation by the breaching party. Additionally, spillover effects occur such that a breach by the host predicts psychological contract violation by the home organization, though not the reverse. These relationships are shaped by the expatriates’ organizational identification. Identification with the host buffers the direct effect between breach and violation by the host, while dual organizational identification mitigates the direct effect between breach and violation by the home organization. Identification with the home organization diminishes the spillover effect from host breach to home organization violation. The opposite, identification with the host, amplifies the spillover effect of host breach to home organization violation. By examining the distinct dynamics of home and host organization contract breach and violation, we develop theoretical implications for understanding PCs in multi-party work arrangements

    One way or another? An international comparison of expatriate performance management in multinational companies

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    Due to the high costs and strategic importance of expatriate assignments, expatriate performance management (EPM) plays an increasingly important role for multinational enterprises (MNEs). However, research on EPM is still in its infancy. Drawing from the convergence/divergence debate in international human resource management, this study investigates and compares EPM strategies and practices across MNEs from three different country clusters to better understand whether EPM practices tend to converge, diverge, or crossverge (i.e., show aspects of both). Results from surveying 132 Anglo‐Saxon, Germanic, and Japanese MNEs reveal prominent differences (divergence) at the EPM strategic level such that Japanese MNEs tend to pursue more ethnocentric staffing strategies and design EPM systems specifically tailored to expatriates

    Managing people in hostile environments: lessons learned and new grounds in HR research

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    Questions related to managing people in hostile environments have become more central on the agenda of business leaders and HR professionals in MNCs. This is due to developments such as the increase of terrorism or the political instability in many regions. In consequence, research on the role of HR in hostile environments has increased as well, though it can still be considered in its early stages. We would like to review the current state of research on managing people in hostile environment. In particular, with this article we contribute to the literature by developing a conceptual framework that distinguishes between micro-, meso- and marco-level research and charts progress, mechanisms and results. We call this the Situation – Response – Outcome (SRO) Framework of HRM in hostile environments. Depending on the level of analysis, the framework further differentiates between a pre-crises, acute-crisis, and post-crises phases of HRM in hostile environments. As a result, it serves as the basis to cluster existing literature around it and to show avenues for future research

    Functional characterization of GABAA receptor-mediated modulation of cortical neuron network activity in microelectrode array recordings

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    The numerous γ-aminobutyric acid type A receptor (GABAAR) subtypes are differentially expressed and mediate distinct functions at neuronal level. In this study we have investigated GABAAR-mediated modulation of the spontaneous activity patterns of primary neuronal networks from murine frontal cortex by characterizing the effects induced by a wide selection of pharmacological tools at a plethora of activity parameters in microelectrode array (MEA) recordings. The basic characteristics of the primary cortical neurons used in the recordings were studied in some detail, and the expression levels of various GABAAR subunits were investigated by western blotting and RT-qPCR. In the MEA recordings, the pan-GABAAR agonist muscimol and the GABABR agonist baclofen were observed to mediate phenotypically distinct changes in cortical network activity. Selective augmentation of αβγ GABAAR signaling by diazepam and of δ-containing GABAAR (δ-GABAAR) signaling by DS1 produced pronounced changes in the majority of the activity parameters, both drugs mediating similar patterns of activity changes as muscimol. The apparent importance of δ-GABAAR signaling for network activity was largely corroborated by the effects induced by the functionally selective δ-GABAAR agonists THIP and Thio-THIP, whereas the δ-GABAAR selective potentiator DS2 only mediated modest effects on network activity, even when co-applied with low THIP concentrations. Interestingly, diazepam exhibited dramatically right-shifted concentration-response relationships at many of the activity parameters when co-applied with a trace concentration of DS1 compared to when applied alone. In contrast, the potencies and efficacies displayed by DS1 at the networks were not substantially altered by the concomitant presence of diazepam. In conclusion, the holistic nature of the information extractable from the MEA recordings offers interesting insights into the contributions of various GABAAR subtypes/subgroups to cortical network activity and the putative functional interplay between these receptors in these neurons

    teaMPI---replication-based resiliency without the (performance) pain.

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    In an era where we can not afford to checkpoint frequently, replication is a generic way forward to construct numerical simulations that can continue to run even if hardware parts fail. Yet, replication often is not employed on larger scales, as naïvely mirroring a computation once effectively halves the machine size, and as keeping replicated simulations consistent with each other is not trivial. We demonstrate for the ExaHyPE engine—a task-based solver for hyperbolic equation systems—that it is possible to realise resiliency without major code changes on the user side, while we introduce a novel algorithmic idea where replication reduces the time-to-solution. The redundant CPU cycles are not burned “for nothing”. Our work employs a weakly consistent data model where replicas run independently yet inform each other through heartbeat messages whether they are still up and running. Our key performance idea is to let the tasks of the replicated simulations share some of their outcomes, while we shuffle the actual task execution order per replica. This way, replicated ranks can skip some local computations and automatically start to synchronise with each other. Our experiments with a production-level seismic wave-equation solver provide evidence that this novel concept has the potential to make replication affordable for large-scale simulations in high-performance computing
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