143,126 research outputs found
Bad Data Injection Attack and Defense in Electricity Market using Game Theory Study
Applications of cyber technologies improve the quality of monitoring and
decision making in smart grid. These cyber technologies are vulnerable to
malicious attacks, and compromising them can have serious technical and
economical problems. This paper specifies the effect of compromising each
measurement on the price of electricity, so that the attacker is able to change
the prices in the desired direction (increasing or decreasing). Attacking and
defending all measurements are impossible for the attacker and defender,
respectively. This situation is modeled as a zero sum game between the attacker
and defender. The game defines the proportion of times that the attacker and
defender like to attack and defend different measurements, respectively. From
the simulation results based on the PJM 5 Bus test system, we can show the
effectiveness and properties of the studied game.Comment: To appear in IEEE Transactions on Smart Grid, Special Issue on Cyber,
Physical, and System Security for Smart Gri
Selection of the key earth observation sensors and platforms focusing on applications for Polar Regions in the scope of Copernicus system 2020-2030
An optimal payload selection conducted in the frame of the H2020 ONION project (id 687490) is presented based on the ability to cover the observation needs of the Copernicus system in the time period 2020–2030. Payload selection is constrained by the variables that can be measured, the power consumption, and weight of the instrument, and the required accuracy and spatial resolution (horizontal or vertical). It involved 20 measurements with observation gaps according to the user requirements that were detected in the top 10 use cases in the scope of Copernicus space infrastructure, 9 potential applied technologies, and 39 available commercial platforms. Additional Earth Observation (EO) infrastructures are proposed to reduce measurements gaps, based on a weighting system that assigned high relevance for measurements associated to Marine for Weather Forecast over Polar Regions. This study concludes with a rank and mapping of the potential technologies and the suitable commercial platforms to cover most of the requirements of the top ten use cases, analyzing the Marine for Weather Forecast, Sea Ice Monitoring, Fishing Pressure, and Agriculture and Forestry: Hydric stress as the priority use cases.Peer ReviewedPostprint (published version
On Small Satellites for Oceanography: A Survey
The recent explosive growth of small satellite operations driven primarily
from an academic or pedagogical need, has demonstrated the viability of
commercial-off-the-shelf technologies in space. They have also leveraged and
shown the need for development of compatible sensors primarily aimed for Earth
observation tasks including monitoring terrestrial domains, communications and
engineering tests. However, one domain that these platforms have not yet made
substantial inroads into, is in the ocean sciences. Remote sensing has long
been within the repertoire of tools for oceanographers to study dynamic large
scale physical phenomena, such as gyres and fronts, bio-geochemical process
transport, primary productivity and process studies in the coastal ocean. We
argue that the time has come for micro and nano satellites (with mass smaller
than 100 kg and 2 to 3 year development times) designed, built, tested and
flown by academic departments, for coordinated observations with robotic assets
in situ. We do so primarily by surveying SmallSat missions oriented towards
ocean observations in the recent past, and in doing so, we update the current
knowledge about what is feasible in the rapidly evolving field of platforms and
sensors for this domain. We conclude by proposing a set of candidate ocean
observing missions with an emphasis on radar-based observations, with a focus
on Synthetic Aperture Radar.Comment: 63 pages, 4 figures, 8 table
Contention-aware performance monitoring counter support for real-time MPSoCs
Tasks running in MPSoCs experience contention delays when accessing MPSoC’s shared resources, complicating task timing analysis and deriving execution time bounds. Understanding the Actual Contention Delay (ACD) each task suffers due to other corunning tasks, and the particular hardware shared resources in which contention occurs, is of prominent importance to increase confidence on derived execution time bounds of tasks. And, whenever those bounds are violated, ACD provides information on the reasons for overruns. Unfortunately, existing MPSoC designs considered in real-time domains offer limited hardware support to measure tasks’ ACD losing all these potential benefits. In this paper we propose the Contention Cycle Stack (CCS), a mechanism that extends performance monitoring counters to track specific events that allow estimating the ACD that each task suffers from every contending task on every hardware shared resource. We build the CCS using a set of specialized low-overhead Performance Monitoring Counters for the Cobham Gaisler GR740 (NGMP) MPSoC – used in the space domain – for which we show CCS’s benefits.The research leading to these results has received funding from the European Space Agency under contracts 4000109680,
4000110157 and NPI 4000102880, and the Ministry of Science and Technology of Spain under contract TIN-2015-65316-P.
Jaume Abella has been partially supported by the Ministry of Economy and Competitiveness under Ramon y Cajal postdoctoral fellowship number RYC-2013-14717.Peer ReviewedPostprint (author's final draft
Resource-Based View and SMEs Performance Exporting through Foreign Intermediaries: The Mediating Effect of Management Controls
Following the resource-based view, this research empirically explores the role of formal and informal management control in mobilizing export resources to develop export capabilities, influencing the export performance of small and medium-sized enterprises (SMEs) in an interorganizational relationship context. Empirical data were collected using a survey administrated online to finance managers in Spanish SMEs which use foreign intermediaries to access export markets. In this setting, evidence mainly suggests, first, that management control systems (MCSs) play a relevant mediating role between the effect of, on the one hand, resources on capabilities, and, on the other hand, resources and capabilities on performance. Second, that MCSs and capabilities play a interrelated double mediating effect between the impact of resources on performance; more specifically, a significant double indirect effect is found (1) between financial resources, behavior control, customer relationship building capability and performance, and (2) between physical resources, behavior control, customer relationship building capability and performanc
Coverage and mobile sensor placement for vehicles on predetermined routes: a greedy heuristic approach
Road potholes are not only nuisance but can also damage vehicles and pose serious safety risks for drivers. Recently, a number of approaches have been developed for automatic pothole detection using equipment such as accelerometers, image sensors or LIDARs. Mounted on vehicles, such as taxis or buses, the sensors can automatically detect potholes as the vehicles carry out their normal operation. While prior work focused on improving the performance of a standalone device, it simply assumed that the sensors would be installed on the entire fleet of vehicles. When the number of sensors is limited it is important to select an optimal set of vehicles to make sure that they do not cover similar routes in order to maximize the total coverage of roads inspected by sensors. The paper investigates this problem for vehicles that follow pre-determined routes, formulates it as a linear optimization problem and proposes a solution based on a greedy heuristic. The proposed approach has been tested on an official London bus route dataset containing 713 routes and showed up to 78% improvement compared to a random sensor placement selected as a baseline algorithm
Road Pricing: The Potential for Comparative Monitoring. A Report to the London Planning Advisory Committee.
This study was designed to review the proposals for road user charging in the Randstad, Stockholm, Oslo and Singapore, to determine the intentions for monitoring of each of these proposed schemes, to assess the implications for the development of policy in London, and to identify any opportunities for obtaining experience which would help in clarifying the uncertainties associated with proposals for road pricing in London. The study reviewed the objectives and operational requirements for road pricing in London and the criticisms levelled against such proposals. On this basis it developed a series of requirements for monitoring and information gathering to help clarify the outstanding uncertainties. These were used as a check list for a series of discussions with those responsible for proposals in the case study cities. Discussions indicated that the proposals in most cities had changed markedly in the period since the study was commissioned. These changes, and the resulting nature of the proposals, meant that only the proposals for Stockholm were sufficiently similar to those in London to justify collaborative monitoring. The report recommends that such collaboration be developed. However, both the Randstad and Oslo schemes offer the opportunity for obtaining information on actual or predicted user response, while the Singapore proposals will provide valuable experience of new technology. It is recommended that all of these are pursued. The discussions highlighted several lessons of direct relevance to the development of policy in London. In particular it is seen as important to keep the specification of the measures simple; to pursue extensive consultation with those who might be affected and with all political parties and government bodies who might be involved in policy decisions; to provide clear guidance on the anticipated uses of the revenue: and to develop a system which is implemented flexibly, so that problems can be remedied as they arise.
In this context, the role of assessment and monitoring is limited. It should not be used to delay decisions; however, once a commitment is made to proceed, experience from elsewhere will be of value in informing the consultations. A carefully designed monitoring programme will be important in assessing and enhancing a scheme once implemented. It is recommended that the monitoring programme should be based on the requirements identified in this report
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