34,068 research outputs found
Key Extraction from the Primary Side of a Switched-Mode Power Supply
In this paper we detail techniques that can be used to analyze and attack an AES implementation on an FPGA from the primary (i.e., external) side of a switched-mode power supply. Our attack only requires measurements of the duty cycle of the power supply, and then increases the signal-to-noise ratio (SNR) though averaging, deconvolution and wavelet based detrending. The result is an exploitable source of leakage that allows a secret key to be determined from low-frequency power measurements. The techniques and procedures provide a general approach to performing differential power analysis (DPA) from a single point of information for any single hypothesized intermediate value, suggesting their potential for improving other types of side-channel analysis
Remote real-time monitoring of subsurface landfill gas migration
The cost of monitoring greenhouse gas emissions from landfill sites is of major concern for regulatory authorities. The current monitoring procedure is recognised as labour intensive, requiring agency inspectors to physically travel to perimeter borehole wells in rough terrain and manually measure gas concentration levels with expensive hand-held instrumentation. In this article we present a cost-effective and efficient system for remotely monitoring landfill subsurface migration of methane and carbon dioxide concentration levels. Based purely on an autonomous sensing architecture, the proposed sensing platform was capable of performing complex analytical measurements in situ and successfully communicating the data remotely to a cloud database. A web tool was developed to present the sensed data to relevant stakeholders. We report our experiences in deploying such an approach in the field over a period of approximately 16 months
Electrical Loads and Power Systems for the DEMO Nuclear Fusion Project
EU-DEMO is a European project, having the ambitious goal to be the first demonstrative
power plant based on nuclear fusion. The electrical power that is expected to be produced is in the
order of 700â800 MW, to be delivered via a connection to the European High Voltage electrical grid.
The initiation and control of fusion processes, besides the problems related to the nuclear physics,
need very complex electrical systems. Moreover, also the conversion of the output power is not
trivial, especially because of the inherent discontinuity in the EU-DEMO operations. The present
article concerns preliminary studies for the feasibility and realization of the nuclear fusion power
plant EU-DEMO, with a special focus on the power electrical systems. In particular, the first stage of
the study deals with the survey and analysis of the electrical loads, starting from the steady-state
loads. Their impact is so relevant that could jeopardy the efficiency and the convenience of the plant
itself. Afterwards, the loads are inserted into a preliminary internal distribution grid, sizing the main
electrical components to carry out the power flow analysis, which is based on simulation models
implemented in the DIgSILENT PowerFactory software
Systems study for an Integrated Digital-Electric Aircraft (IDEA)
The results of the Integrated Digital/Electric Aircraft (IDEA) Study are presented. Airplanes with advanced systems were, defined and evaluated, as a means of identifying potential high payoff research tasks. A baseline airplane was defined for comparison, typical of a 1990's airplane with advanced active controls, propulsion, aerodynamics, and structures technology. Trade studies led to definition of an IDEA airplane, with extensive digital systems and electric secondary power distribution. This airplane showed an improvement of 3% in fuel use and 1.8% in DOC relative to the baseline configuration. An alternate configuration, an advanced technology turboprop, was also evaluated, with greater improvement supported by digital electric systems. Recommended research programs were defined for high risk, high payoff areas appropriate for implementation under NASA leadership
Enhancing the environmental sustainability of IT
Emerging technologies for learning report - Article exploring green I
Case studies of outdoor testing and analysis of building components
The construction and development of the PASSYS/PASLINK outdoor test cells were funded by the European Commission, with the objective of providing high-quality test environments for quantifying the performance of passive solar building components. Over the years since the original test cells were commissioned, the initial concept for outdoor testing has been extended to include other test cell types. Significant improvements have been made to the experimental procedures and analysis techniques, and a broad range of components has been tested. This paper describes representative experiments that have been conducted using these highly controlled outdoor test environments, indicates some of the related analysis, and shows the type of information that can be obtained from such tests. It demonstrates the way in which component performance can be ascertained in the realistic external environment. The case studies chosen range from building component tests within EC research projects to commercial tests, and from conventional building components to novel integrated facade systems. They also include a large range of passive and active components. Each case study summarises the test component, the purpose of the test, details of the test configuration (period of test, instrumentation, etc.), results and analysis, and associated modelling and monitoring where appropriate. The paper concludes with an appraisal of the advantages and limitations of the test cells for the various component types
Technological Aspects: High Voltage
This paper covers the theory and technological aspects of high-voltage design
for ion sources. Electric field strengths are critical to understanding
high-voltage breakdown. The equations governing electric fields and the
techniques to solve them are discussed. The fundamental physics of high-voltage
breakdown and electrical discharges are outlined. Different types of electrical
discharges are catalogued and their behaviour in environments ranging from air
to vacuum are detailed. The importance of surfaces is discussed. The principles
of designing electrodes and insulators are introduced. The use of high-voltage
platforms and their relation to system design are discussed. The use of
commercially available high-voltage technology such as connectors, feedthroughs
and cables are considered. Different power supply technologies and their
procurement are briefly outlined. High-voltage safety, electric shocks and
system design rules are covered.Comment: 39 pages, contribution to the CAS-CERN Accelerator School: Ion
Sources, Senec, Slovakia, 29 May - 8 June 2012, edited by R. Bailey,
CERN-2013-00
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A holographic system for subsea recording and analysis of plankton and other marine particles
We report here details of the design, development, initial testing and field-deployment of the HOLOMAR system for in-situ subsea holography and analysis of marine plankton and nonliving particles. HOLOMAR comprises a submersible holographic camera ("HoloCam") able to record in-line and off-axis holograms at depths down to 100 m, together with specialised reconstruction hardware ("HoloScan") linked to custom image processing and classification software. The HoloCam consists of a laser and power supply, holographic recording optics and holographic plate holders, a water-tight housing and a support frame. It utilises two basic holographic geometries, in-line and off-axis such that a wide range of species, sizes and concentrations can be recorded. After holograms have been recorded and processed they are reconstructed in full three-dimensional detail in air in a dedicated replay facility. A computer-controlled microscope, using video cameras to record the image at a given depth, is used to digitise the scene. Specially written software extracts a binarised image of an object in its true focal plane and is classified using a neural network. The HoloCam was deployed on two separate cruises in a Scottish sea loch (Loch Etive) to a depth of 100 m and over 300 holograms were recorded
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