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This paper is giving an overview of personal experience in research, development and testing of many types of vacuum switching devices. The common denominator is high-frequency (HF) phenomena.The overview starts with vacuum arc instability and current chopping and goes on into HF current interruption, first related to small-current interruption in research-type and commercial low-surge interrupters, later to high-voltage DC vacuum circuit breakers using very large HF currents. The fast phenomena occurring upon ‘late’ breakdown are discussed including analysis of field-electron emission (FEE) current. A conclusion is that FEE is not directly related to late breakdown in a full-power set-up.High-current interruption is discussed showing evidence of very large post-arc current in practical fault interruption. Modelling attempts of high-current interruption shows the complexity of the processes. An example of a hybrid vacuum/SF6 circuit breaker is discussed.In the second part of the paper, the author’s observations and expectations on high-voltage vacuum circuit breakers, novel actuators and insulation issues are shared. Trends and future directions of vacuum switching technology are reviewed, including research gaps and opportunities.

NATO member states are starting to talk more openly about the incentives and opportunities to conduct offensive cyber operations for military purposes. This growing interest in ‘offensive cyber’ is most clearly expressed in the creation of cyber commands, branches or services within the armed forces. Little research, however, has analyzed these organizational developments. This article provides a conceptual framework to facilitate empirical analysis across military cyber organizations (MCOs). The framework distinguishes between five stages of organizational development: i) seed, ii) startup, iii) growth, iv) expansion, and v) maturity. Our empirical analysis reveals that a significant number of NATO members started to carefully consider establishing MCOs from 2008 onwards, and some states had already started significant organizational efforts in the 1990s. However, I also reveal that the MCOs of most NATO members are still at the early stages of organizational development, and even those at the growth stage still have limited budgets to address the different workforce, capability, strategic and other requirements.

Sleep apnea is one of the most common sleep disorders. It is characterized by the cessation of breathing during sleep due to airway blockages (obstructive sleep apnea) or disturbances in the signals from the brain (central sleep apnea). The gold standard for diagnosing sleep apnea is performing an overnight polysomnography recording which contains, among others, a wide array of respiratory signals. Respiration information can also be extracted from other physiological signals such as an electrocardiogram or from a bio-impedance measurement on the chest. Studies have shown that algorithms can be developed for automated sleep apnea detection using one of these many respiratory signals. In this work, the predictive power of these different respiratory signals is analyzed and compared. The results provide useful insights into the comparative predictive power of the different respiratory signals in a realistic setting for automated sleep apnea detection and provide a basis for the development of less obtrusive measurement techniques.

There is a growing interest in the use of offensive cyber capabilities (OCC) among states. Despite the growing interest in these capabilities, little is still known about the nature of OCC as a tool of the state. This research therefore aims to understand if (and how) offensive cyber capabilities have the potential to change the role of military power. Drawing on a wide range of cases, we argue that these capabilities can alter the manner in which states use their military power strategically in at least four ways. OCC are not particularly effective in deterring adversary military action, except when threatened to be used by states with a credible reputation. However, they do have value in compellence. Unlike conventional capabilities, the effects of offensive cyber operations do not necessarily have to be exposed publicly, which means the compelled party can back down post-action without losing face thus deescalating conflict. The potential to control the reversibility of effect of an OCC by the attacker may also encourage compliance. OCC also contribute to the use of force for defensive purposes, as it could provide both a preemptive as well as preventive strike option. Finally, its symbolic value as a 'prestige weapon' to enhance 'swaggering' remains unclear, due to its largely non-material ontology and transitory nature.

Nowadays, a clear trend of increase of system voltage to 800 kV AC and above can be observed in the world. This calls for the need of having test facilities to verify the fault current interruption performance of circuit breakers for such “super grids”. Standard synthetic test-methods for fault current interruption verification cannot be applied to circuit breakers of 800 kV and above, and alternative solution must be searched for. The present contribution highlights the test-circuits and test-methods that the author's laboratories have developed in recent year to be able to carry out a full test-program of short-circuit tests on circuit breakers up to 1200 kV. For such tests, separate, well-synchronized sources for the supply of fault current and transient recovery voltage (TRV) are required, combined to synthetic test circuits. In this contribution, it is shown how this principle is stretched further to be applied for UHV (above 800 kV) switchgear. A recently commissioned system of a two-stage synthetic installation is demonstrated, with actual test examples of 800 and 1100 kV circuit breakers, for which TRV's in excess of 2000 kV are required. A key feature of the test-circuit is that the circuit breaker under test can remain on ground, which greatly facilitates efficient testing compared to test approaches in which the breaker must be installed on an isolated platform. In case of three poles of a circuit breakers being mounted in a single enclosure, the international standards require synthetic testing of each pole simultaneously. The expansion of the laboratory with a new synthetic installation enables full three-phase synthetic testing, even under effectively earthed conditions, examples of which will be shown. In addition, three-phase closing ('making') tests will be illustrated, including the full power testing of a switch, designed to activate closing resistors in an 800 kV GIS circuit breaker.

High voltage direct current circuit breakers (HVDC CBs) are necessary for reliable and safe operation of future multi-terminal meshed HVDC grids. So far no commercially mature products of such equipment exist. A few industrial concepts as a result of advances in power electronics have been proposed and prototypes have been built. However, performances of these concepts have never been demonstrated under realistic operation conditions. Since these tests require construction of high power DC sources incurring significant investment costs, alternative test circuits providing equivalent stresses must be considered. In this paper various test methods and circuits used for testing HVDC CBs are investigated and their performance is evaluated against the stresses in a conceptual future HVDC grid. A novel method of testing an HVDC CB using existing installations in a high power ac test laboratory is proposed and its prospective fault current and voltage is experimentally demonstrated. It is concluded that adequate test circuits need to maintain the supply voltage not only up to the current zero in the main interrupter unit of the HVDC CB, but also during the entire energy dissipation phase of the interruption process.

Organisational Integration has become a key agenda point for policy-makers as governments continue to change and create new organisations to address the cyber threat. Passing references on this topic, however, far outnumber systematic treatments. The aim of this paper is to investigate the potential effects of organisational integration of offensive cyber capabilities (OIOCC). I argue that OIOCC may lead to three key benefits: enhanced interaction efficiency, greater knowledge transfer and improved resource allocation. There are, however, several negative effects of integration, which have so far received little attention. OIOCC may lead to an intensification of the cyber security dilemma, increase costs overall, and impel ‘cyber mission creep’. Though the benefits seem to outweigh the risks, I note that ignoring the potential negative effects may be dangerous, as activity is more likely to go beyond the foreign-policy goals of governments and intrusions are more likely to trigger a disproportionate response by the defender.

Passive assistive devices that compensate gravity can reduce human effort during transportation of heavy objects. The additional reduction of inertial forces, which are still present during deceleration when using gravity compensation, could further increase movement performance in terms of accuracy and duration. This study investigated whether position dependent damping forces (PDD) around targets could assist during planar reaching movements. The PDD damping coefficient value increased linearly from 0 Ns/m to 200 Ns/m over 18 cm (long PDD) or 9 cm (short PDD). Movement performance of reaching with both PDDs was compared against damping free baseline conditions and against constant damping (40 Ns/m). Using a Fitts' like experiment design 18 subjects performed a series of reaching movements with index of difficulty: 3.5, 4.5 and 5.5 bits, and distances 18, 23 and 28 cm for all conditions. Results show that PPD reduced (compared to baseline and constant damping) movement times by more than 30% and reduced the number of target reentries, i.e. increasing reaching accuracy, by a factor of 4. Results were inconclusive about whether the long or short PDD conditions achieved better task performance, although mean human acceleration forces were higher for the short PDD, hinting at marginally faster movements. Overall, PDD is a useful haptic force to get humans to decrease their reaching movement times while increasing their targeting accuracy.

In the present work, we investigate light-management concepts applied subsequent to the passivation of the Si wafer of planar Si heterojunction solar cells. As a first concept, we apply amorphous silicon based nanophotonic textures at the back side of the Si wafer to realize efficient light trapping. As a second concept, we use a nanoimprint lithography based front side anti-reflection coating to improve the incoupling of light into the solar cell absorber. Both concepts allow for efficient improvements in the short-circuit current densities without degrading the planar passivation layers. As the highlight of this work, we demonstrate planar silicon heterojunction solar cells (thickness ∼ 280 μm) with high passivation quality as well as a short-circuit current density of 38.8 mA/cm2.

© 2016 IEEE. In this paper, a new single-image super-resolution method is presented to increase the spatial resolution of metabolite maps computed from magnetic resonance spectroscopic imaging. The proposed method is based on a non-local patch-based strategy that uses a high resolution T1-weighted image to regularise the super-resolution process. The method is implemented in a multi-scale fashion. The accuracy of the method is validated on both phantom and in vivo images. Both qualitative and quantitative validation suggest that the method has potential for clinically relevant neuroimaging applications. Jain S., Sima D., Sanaei Nezhad F., Williams S., Van Huffel S., Maes F., Smeets D., ''Patch based super-resolution of MR spectroscopic images'', Proceedings 13th IEEE international symposium on biomedical imaging - ISBI 2016, pp. 452-456, April 13-16, 2016, Prague, Czech Republic. ispartof: pages:452-456 ispartof: Proceedings ISBI 2016 vol:2016-June pages:452-456 ispartof: IEEE international symposium on biomedical imaging - ISBI 2016 location:Prague, Czech Republic date:13 Apr - 16 Apr 2016 status: published

In recent years, the demand for testing of inductive load current switching duties has significantly increased. Parallel to this, a range of changes to the IEC standard 62271-110 have become effective. This contribution is intended to give an overview on some recent test experiences in inductive load switching with circuit breakers in a voltage range 12–550 kV, showing practical examples, changes and interpretations of the latest IEC standard. In the first part, an introduction will be given on the inductive switching duty, its typical features and its standard, IEC 62271-110. In the second part, vacuum circuit breakers are considered. Compared to SF6 circuit breakers, the re-ignition pattern differs significantly, given the inherent capability of vacuum circuit breakers to interrupt high-frequency current. This was identified by CIGRE WG A3.27 on high-voltage vacuum circuit breakers. Test-examples of vacuum breakers up to 84 kV regarding shunt-reactor switching are shown and explained in its Technical Brochure 589from 2014. Also, test-examples of HV motor switching, and the inherent overvoltages due to multiple reignition and virtual current chopping are highlighted and explained quantitatively. In the third part, shunt reactor switching with EHV circuit breakers is considered. Test examples will be highlighted of 550 kV circuit breakers. Recent publications have shown that more and more air-core shunt reactors are applied at EHV level. It will be demonstrated that in such cases, TRV requirements, in excess of those, as specified in the IEC standard may be met.

DC circuit breakers are essential components in the protection of multi-terminal and meshed DC grids. So far, no practical application of HVDC circuit breakers is known and intense research is being carried out regarding various concepts, practical realization and ultimately testing of such devices. In the present contribution, several breaker concepts, based on the hybrid method of DC fault current interruption, described in (patent-) literature, are modelled in order to investigate their interaction with a DC grid. For this purpose, the CIGRE B4 test-system, a combination of DC and AC grids, consisting of multiple in-feeds and having lines and cables, is modelled. The impact of a fault on the breaker is considered. Since industrial concepts of hybrid HVDC breakers are modelled including their key elements, the electrical stresses on various parts of the breakers are analyzed in detail. These stresses are used as a guide to design high-power test circuits that can be used to test DC switchgear under realistic conditions. Two classes of DC test circuits are considered and investigated based on high-power test circuits, supplied by AC generators: • One class can produce pseudo-DC currents of short duration that can be adequate to test DC equipment (including switchgear) under normal and fault conditions. Three basic circuits will be demonstrated and compared. • Another class is a set of basic test-circuits having capability of creating similar stresses on HVDC circuit breakers as in service. Four basic circuits are investigated and compared to an ideal DC circuit: discharge of a charged high-current reactor, discharge of a charged high-voltage capacitor bank and high-power high-voltage AC circuits of 16.7 and 50 Hz. Comparison of each of these circuits shows that low frequency AC circuits are possible candidates to represent the interaction of HVDC circuit breaker with a DC circuit adequately; regarding fault current rise, interruption performance, counter voltage creation and energy management.

A new technique to monitor the fluid status of congestive heart failure (CHF) patients in the hospital is proposed and verified in a clinical trial with 8 patients. A wearable Bio-impedance (BioZ) sensor allows a continuous localized measurement which can be complement clinical tools in the hospital. Thanks to the multi-parametric approach and correlation analysis with clinical reference, BioZ is successfully shown as a promising parameter for continuous and wearable CHF patient monitoring application.

Transformers belong to the crucial components in distribution and transmission networks. Reliable use for many years needs to be guaranteed. Besides quality assurance of the manufacturer type testing is the most common way to prove this reliability under normal and extreme conditions. In addition, for dry-type transformers, special tests to prove climatic (C), environmental (E) and fire behaviour (F) class are defined in the international standard IEC 60076-11. End users, e.g. utilities and wind turbine manufacturers, are demanding proof of the claimed qualities of dry-type transformers increasingly. The independent KEMA laboratories, owned by DNV-GL, gained large testing experience for C and E class verification. In 2013 also verification for F class was added to KEMA laboratories portfolio, where now experience has been built-up. For C class verification, a thermal shock test is to be performed. The most common failure is the appearance of cracks, found during visual inspection after the test. The most important part for E2 class verification is the performance of a condensation test, where the transformer is energized while salt condensation is to be present on the surfaces of the object. Failures are flashovers causing voltage breakdowns and serious tracking degrading the transformers dielectric qualities. As part of the F class verification, a complete assembled phase of a transformer is set on fire in a test chamber equipped with air inlet and chimney. Temperatures in the chimney above the allowed limits will lead to unsuccessful results. In the last five years, many (> 40) dry-type distribution transformers (power range up to 3,5 MVA) were tested for verification of one or more of these classes. Often (> 50%) the requirements as per IEC 60076-11 and/or clients specifications could not be met. In some cases design changes and retests were required to meet the requirements, in other cases test programs were stopped due to failure of the object. This paper will explain the importance of the above mentioned tests. Also explanation will be given on the testing methods and procedures required for reliable and reproducible tests, results and conclusions. Climatic, environmental and fire behaviour tests are important special tests proving utilities and other end users of dry-type transformers the quality of the product.

The most critical transient a circuit breaker has to endure during its operation is the transient recovery voltage (TRV), initiated by the electric power system as a natural reaction on current interruption. For circuit breakers intended to operate in ultra-high voltage systems (with rated voltage above 800 kV), the realization of realistic transient recovery voltages in testing of these circuit breakers becomes a real challenge. In this contribution a new and proven method is described of creating adequate TRVs by a double stage synthetic test circuit. Due to the extremely high voltages to be applied immediately after interruption of very high fault current, a two-stage approach is necessary. This is the only way to perform full-pole testing, the realistic laboratory simulation of service conditions during fault current interruption.

The characteristic dose profile of accelerated ions has opened up new horizons in the context of cancer treatment. However, particle range uncertainties strongly constrain the potentialities of ion beam therapy. In spite of worldwide efforts, a detector system for range and dose delivery assessment in real-time is not yet available for clinical routine.

As demonstrated by the recent attack on Intel's Ivy Bridge processor, the traditional Logic Built-In Self-Test (LBIST) methods do not provide adequate protection of SoC against malicious modifications known as hardware Trojans. In this paper, we introduce a simple but efficient countermeasure against hardware Trojans which exploits non-zero aliasing probability of LBIST. We propose to generate LBIST test patterns based on a configurable key which is decided and programed into the circuit after the manufacturing stage. Since the key and hence expected LBIST signature are unknown at the manufacturing stage, an attack based on selecting suitable values for the Trojan which result in the same signature as a fault-free circuit signature becomes infeasible.

Mobile networks today are divided into multiple radio access technologies (RATs) scattered over a variety of frequencies and functionality depending on the network region. The scattered networks require that the digital baseband for mobile user equipment handle multiple RATs, multiple bands, as well as seamlessly transition between these. In 3GPP release 10 [1] the problem with scattered frequency bands has been addressed by the possibility to aggregate spectrum from two separated carriers to create a wider aggregated total bandwidth. Which carriers to combine depends on the spectrum available to the specific operator.

Haptic guidance systems support the operator in task execution using additional forces on the input device. Scaling of the guidance forces determines the control authority of the support system. As task complexity may vary, one level of the guidance scaling may be insufficient, and adaptation of the control authority may be helpful. The available literature mostly proposed to adapt the authority based on external cues (e.g. actual performance or safety) and the user had no direct way to modulate the desired level of support. In this paper we investigated a variable authority guidance scheme based on the user grip force. During a user study (with 8 subjects) we explored two opposite approaches to trade the control authority (i.e. increasing or decreasing guidance force magnitude with increased user grip). To simulate increased task difficulty and imperfections of the haptic guidance system, at random times either an unpredictable force disturbance was added or subjects were presented with incorrect guidance. While the performance differences between the fixed- and the variable-authority schemes were not significant, the "decreasing guidance with increased user grip" scheme allowed to substantially reduce the user control effort (steering force), especially when the guidance system was incorrect. The presented method essentially provides additional control over the guidance system without reducing the performance.

Treatments delivered by proton therapy are affected by uncertainties on the range of the beam within the patient. To reduce these margins and improve feedback on treatment delivery, different projects are investigating real-time range control by imaging prompt gammas emitted along the proton tracks in the patient. This study supports the development of a prompt gamma camera using a knife-edge slit collimator to produce a reversed 1-dimensional projection of the beam path on a scintillation detector for treatments delivered in pencil beam scanning mode. The ability of this camera design to detect modifications of the beam penetration depth in a PMMA target was already demonstrated down to 1 mm accuracy for doses compatible with single pencil beams at low proton beam currents thanks to the HiCam photo-detection system. In order to fulfill the very demanding count rate capability required for prompt gamma imaging at clinical beam currents, a new, dedicated, cost-effective photo-detection system was designed. This 1-dimensional, high-energy gamma imaging device relies on two rows of 20 LYSO crystal slabs, directly coupled to SiPMs' arrays and readout by 40 independent acquisition channels in fast counting mode. A first prototype limited to 20 channels was implemented to benchmark the performances of various components and validate the adequate combination of crystal material, surface treatment, optical coupling and SiPMs. This prototype was tested during proton irradiation at the West German Proton Therapy Centre in Essen at clinical beam currents of several nA at nozzle exit.

Capacitor bank switching can cause significant inrush current to flow during the closing phase of circuit breakers. From test-statistics, it is derived that switching capacitor banks at higher voltage under the IEC 'back-to-back' inrush current condition, is a significant challenge for SF6 and vacuum circuit breakers. In the case of vacuum circuit breakers, field electron emission (FEE) current during the opening phase under full recovery voltage conditions are measured. It was concluded that in spite of the wide variety of measured FEE current magnitude (from tens of μA up to several rnA) there is no direct relationship between magnitude of FEE current and probability of breakdown. Longer arc duration of the normal load current reduces the FEE current level after load current interruption.

From a large number of short-line fault tests with high-voltage SF6 AC circuit breakers with rated voltage 72.5 - 550 kV, a validated arc model is derived that describes the current-zero behaviour of the breaker rather well. This model is used to investigate the possibility to interrupt DC current by means of arc current oscillations with increasing amplitude until current zero is reached. Two aspects are of importance: the excitation of the negatively damped oscillation and the capability to interrupt the high-frequency (few kHz) current. In small scale experiments, using an AC current of 1 kA at 16.7 Hz the capability of exciting negatively damped oscillations with a properly tuned parallel LC circuit was confirmed as predicted by the model. Regarding interruption capability, model predictions show that because of the special conditions, the SF6 arc may interrupt higher di/dt than in a typical AC application.

Summary form only given. The design and development of digital electronic systems is mainly performed by use of a hardware description language. To prepare students in electrical engineering for a career in hardware design many universities provide courses on VHDL. The traditional approach in teaching VHDL is mainly by means of textbook examples and simulation provided by software applications. These exercises are perceived as monotonous by the students and do not or only very slightly correspond with actual real-life applications based on FPGAs. Moreover, most real-life applications are too expensive to be equipped in student laboratories. To bridge the gap between a simulation-only environment and affordable real-life applications students should be provided access to remote real-life setups with a 24/7 availability and preferably shared between multiple institutes. The eDiViDe platform (European Digital Virtual Design Lab, http://www.edivide.eu), see Fig. 1, provides students with this unlimited and exciting access to FPGA based setups. Instead of theory-only courses and a quick basic lab, they can work their way through digital design courses testing their skills on real-life setups to trigger their interest. The platform hosts multiple FPGA setups at different European institutes. These setups are accessible through a web-based interface with video feedback. VHDL development is performed offline, given an entity and specific setup information. All further steps of the FPGA toolchain are performed on the platform. A reservation system takes care of the FPGA programming and student interaction with the setups. Similar initiatives provide stable solutions with educational support [1,2,3]. The eDiViDe platform differentiates with a distributed platform across several institutes and with the support for advanced setups. It is the result of a joint effort and easily expandable with additional setups at any location. At this moment following setups are available: greenhouse, stepper motor control, sea noise emulator, state machine workshop, Geffe generator, pong / game of life, traffic light control, MIPS CPU. This set will be extended with more advanced setups that include e.g. a partial reconfiguration workshop for audio/video filters, a side-channel analysis setup and a mars rover playfield. Besides promoting digital design education, the eDiViDe platform creates a channel to make the research activities in the contributing universities more visible. Industry could also benefit from this platform to promote their brand and products to soon to be engineers.