Search

Background. In colorectal surgery, detecting ureters and mesenteric arteries is of utmost importance to prevent iatrogenic injury and to facilitate intraoperative decision making. A tool enabling ureter- and artery-specific image enhancement within (and possibly through) surrounding adipose tissue would facilitate this need, especially during laparoscopy. To evaluate the potential of hyperspectral imaging in colorectal surgery, we explored spectral tissue signatures using single-spot diffuse reflectance spectroscopy (DRS). As hyperspectral cameras with silicon (Si) and indium gallium arsenide (InGaAs) sensor chips are becoming available, we investigated spectral distinctive features for both sensor ranges. Methods. In vivo wide-band (wavelength range 350-1830 nm) DRS was performed during open colorectal surgery. From the recorded spectra, 36 features were extracted at predefined wavelengths: 18 gradients and 18 amplitude differences. For classification of respectively ureter and artery in relation to surrounding adipose tissue, the best distinctive feature was selected using binary logistic regression for Si- and InGaAs-sensor spectral ranges separately. Classification performance was evaluated by leave-one-out cross-validation. Results. In 10 consecutive patients, 253 spectra were recorded on 53 tissue sites (including colon, adipose tissue, muscle, artery, vein, ureter). Classification of ureter versus adipose tissue revealed accuracy of 100% for both Si range and InGaAs range. Classification of artery versus surrounding adipose tissue revealed accuracies of 95% (Si) and 89% (InGaAs). Conclusions. Intraoperative DRS showed that Si and InGaAs sensors are equally suited for automated classification of ureter versus surrounding adipose tissue. Si sensors seem better suited for classifying artery versus mesenteric adipose tissue. Progress toward hyperspectral imaging within this field is promising.

TROPOMI, the Tropospheric Monitoring Instrument, is a passive UV-VIS-NIR-SWIR trace gas spectrograph in the line of SCIAMACHY (2002) and OMI (2004), instruments with the Netherlands in a leading role. Both instruments are very successful and remained operational long after their nominal life time.

The Tropospheric Monitoring Instrument TROPOMI is ready for system level verification. All sub-units have been integrated and tested and final integration at Dutch Space in Leiden has been completed. The instrument will be subjected to a testing and calibration program and is expected to be ready for delivery to the spacecraft early 2015. Using TROPOMI measurements, scientists will be able to improve and continue the study of the Earth’s atmosphere and to monitor air quality, on both global and local scale. TROPOMI is a passive UV-VIS-NIR-SWIR imaging spectrograph and as such is the next step in a series of successful instruments like SCIAMACHY, GOME and OMI. TROPOMI is the only instrument on the Sentinel 5 Precursor satellite (S5P), indicating also its function as a forerunner for the Sentinel 5 instrument. Compared with its predecessors, TROPOMI will be a major improvement in terms of spatial resolution and data quality. In previous papers on TROPOMI, emphasis has been on the performance specifications and on some novel technologies applied in TROPOMI. This paper provides a short recapitulation of TROPOMI’s main features, presents some test results obtained and provides an overview of the verification steps still to come. Subsystem test results are very promising and we anticipate that TROPOMI will fully meet the user’s expectations.

Acoustic underwater communication is an enabler for the use of autonomous underwater vehicles (AUVs). AUVs can operate in acoustically challenging environments, e.g., near offshore platforms and in harbours. To realize robust underwater communication in such environments, the propagation conditions need to be properly understood. In this paper, the performance of underwater acoustic communication in shallow water harbour environments is investigated. To perform our investigation, channel soundings (i.e., empirical channel impulse responses) captured in the Port of East-Vlissingen (The Netherlands) are employed. In particular, it is investigated how the increase of acoustic reverberation caused by reflections from physical structures in a harbour (e.g., quay walls, jetties, piers) affects the underwater acoustic communication performance. The empirical reverberation obtained from the channel soundings is compared with the modelled two-dimensional equivalent in order to make a distinction between bottom-surface paths and reflections from physical structures in the harbour. The collected channel soundings and their analysis are necessary for the development of novel modulation methods and provide useful input for an improved understanding of the acoustic propagation conditions in harbour environments. The findings in this paper can be used by future tools for autonomous underwater operations.

The Tropospheric Monitoring Instrument TROPOMI is ready for system level verification. All sub-units have been integrated and tested and final integration at Dutch Space in Leiden has been completed. The instrument will be subjected to a testing and calibration program and is expected to be ready for delivery to the spacecraft early 2015. Using TROPOMI measurements, scientists will be able to improve and continue the study of the Earth’s atmosphere and to monitor air quality, on both global and local scale. TROPOMI is a passive UV-VIS-NIR-SWIR imaging spectrograph and as such is the next step in a series of successful instruments like SCIAMACHY, GOME and OMI. TROPOMI is the only instrument on the Sentinel 5 Precursor satellite (S5P), indicating also its function as a forerunner for the Sentinel 5 instrument. Compared with its predecessors, TROPOMI will be a major improvement in terms of spatial resolution and data quality. In previous papers on TROPOMI, emphasis has been on the performance specifications and on some novel technologies applied in TROPOMI. This paper provides a short recapitulation of TROPOMI’s main features, presents some test results obtained and provides an overview of the verification steps still to come. Subsystem test results are very promising and we anticipate that TROPOMI will fully meet the user’s expectations.

TNO has built EBL2; a facility for EUV exposure testing and surface analysis. EBL2 is capable of testing EUV optics, EUV photomasks, pellicles, and other components under controlled conditions, relevant to EUV scanner and source operation at all foreseen source power nodes. The system consists of an EUV beam line coupled to an X-ray Photoelectron Spectroscopy system by an automated sample handler. The current contribution reports on the results of the qualification testing of the EUV beam line. Topics investigated include handling and position control, thermal management, a relevant gas environment, EUV irradiation and metrology, and first EUV exposures.

GAIA is a global space astrometry mission, successor to the Hipparcos mission, launched in 1989. The GAIA spacecraft is being built by EADS Astrium France and is scheduled for launch in 2013. At a distance of 1.5 million km from Earth at Lagrangian point L2, slowly spinning around its axis, GAIA will monitor each target star about 100 times over a 5-year period, precisely measuring its distance, movement, and change in brightness. Through spectrophotometric classification, it will provide the detailed physical properties of each star observed: luminosity, temperature, gravity, and elemental composition. This massive stellar census will provide the basic data to tackle an enormous range of important questions related to the origin, structure, and evolutionary history of our Galaxy. The measurements performed with GAIA will be accurate to 24 microarcsec, about 100 times more accurate than Hipparcos. To achieve this extreme accuracy at an operational temperature of 100 K, the entire GAIA Payload is made out of Silicon Carbide (SiC).

GAIA is a global space astrometry mission, successor to the Hipparcos mission, launched in 1989. The GAIA spacecraft is being built by EADS Astrium France and is scheduled for launch in 2013. At a distance of 1.5 million km from Earth at Lagrangian point L2, slowly spinning around its axis, GAIA will monitor each target star about 100 times over a 5-year period, precisely measuring its distance, movement, and change in brightness. Through spectrophotometric classification, it will provide the detailed physical properties of each star observed: luminosity, temperature, gravity, and elemental composition. This massive stellar census will provide the basic data to tackle an enormous range of important questions related to the origin, structure, and evolutionary history of our Galaxy. The measurements performed with GAIA will be accurate to 24 microarcsec, about 100 times more accurate than Hipparcos. To achieve this extreme accuracy at an operational temperature of 100 K, the entire GAIA Payload is made out of Silicon Carbide (SiC).

Further scaling and miniaturization of nanodevices (nanoelectronics, Quantum devices bio-nano devices for healthcare) brings major manufacturing, metrology and characterization challenges that cannot be met anymore by current techniques. The High Volume Manufacturing industry requires, more than ever, metrology methods that routinely measure structural and material parameters at atomic level in nm-sized structures, with atomic precision, with high throughput, for an ever increasing set of combinations of new materials in 3D structures. The research program 3D nanomanufacturing will enable the transition from 2D to 3D nanostructures, that will support the need for ever more powerful devices. The focus is on the development of instruments and techniques which enable manufacturing and metrology of nanostructures at the very high speeds, accuracies and reliabilities required for industrial applications.

Optical components such as diffraction gratings are widely used in Space-flight satellites to analyse light properties from soft-X rays to Infra-Red. The diffraction gratings are one of the key optical components of space-flight instruments and have to exhibit very high optical performances. TROPOMI (Tropospheric Monitoring Instrument) is a spectrometer to measure the tropospheric composition for climate and air quality applications. TROPOMI is the payload of the Sentinel-5 Precursor mission which is a collaborative effort of ESA and the Netherlands Space Office (NSO), part of the GMES Space Component Programme. For TROPOMI, HORIBA Jobin Yvon SAS (France) has designed, produced and characterized, in collaboration with TNO, a set of blazed holographic plane reflexion gratings optimized in the UV spectral range. HORIBA Jobin Yvon SAS (HJY) has been producing such gratings for space experiments since 1968 and has produced some of the most technically-challenging space-flight gratings ever designed, applications ranging from off-plane X-ray gratings to toroidal Variable-Line-Spacing (VLS) gratings for the VUV and transmission deep groove gratings for the IR range.

The LISA Optical Stability Characterization project is part of the LISA CTP activities to achieve the required TRL level for all of the LISA technologies used. In 2012 the LISA mission was reformulated and transferred to the New Gravitational Observatory (NGO), which has similar performance requirements. This activity targets the demonstration of the Telescope Assembly (TA), with a structure based on CFRP technology, to show that total deformations corresponding to a system CTE of 10-7 K-1 can be passively achieved, i.e., without a dedicated thermal control. In addition it is required to prove that the structure exhibits highly predictable mechanical distortion characteristics when cooling down to ˗90°C, during outgassing in space and when going from 1g environment to 0g. A dedicated test setup is designed and realized to allow monitoring dimensional variations of the TAstructure using three interferometers, while varying the temperature in a thermal vacuum chamber. Critical parameters of the verification setup are the length metrology accuracy in thermal vacuum and the stability. For practical application also a high degree of flexibility and ease of operation are required. The test programme includes CTE measurements and thermal gradient characterization of the Telescope Assembly. This paper describes the current development status of the telescope structure. Previously the test facilities as well as the first test results were presented. In this paper the results of these thermal vacuum experiments are described. These results then are analyzed using FEM analysis and compared to the predicted performance. From this comparison modifications are derived to finely trim the thermo-elastic behavior of the telescope assembly. A second thermal vacuum experiment is performed to validate the improved thermo-elastic performance of this off-axis telescope. A third experiment has been performed, which confirms the findings of the second test.

Optical components such as diffraction gratings are widely used in Space-flight satellites to analyse light properties from soft-X rays to Infra-Red. The diffraction gratings are one of the key optical components of space-flight instruments and have to exhibit very high optical performances. TROPOMI (Tropospheric Monitoring Instrument) is a spectrometer to measure the tropospheric composition for climate and air quality applications. TROPOMI is the payload of the Sentinel-5 Precursor mission which is a collaborative effort of ESA and the Netherlands Space Office (NSO), part of the GMES Space Component Programme. For TROPOMI, HORIBA Jobin Yvon SAS (France) has designed, produced and characterized, in collaboration with TNO, a set of blazed holographic plane reflexion gratings optimized in the UV spectral range. HORIBA Jobin Yvon SAS (HJY) has been producing such gratings for space experiments since 1968 and has produced some of the most technically-challenging space-flight gratings ever designed, applications ranging from off-plane X-ray gratings to toroidal Variable-Line-Spacing (VLS) gratings for the VUV and transmission deep groove gratings for the IR range.

Further scaling and miniaturization of nanodevices (nanoelectronics, Quantum devices bio-nano devices for healthcare) brings major manufacturing, metrology and characterization challenges that cannot be met anymore by current techniques. The High Volume Manufacturing industry requires, more than ever, metrology methods that routinely measure structural and material parameters at atomic level in nm-sized structures, with atomic precision, with high throughput, for an ever increasing set of combinations of new materials in 3D structures. The research program 3D nanomanufacturing will enable the transition from 2D to 3D nanostructures, that will support the need for ever more powerful devices. The focus is on the development of instruments and techniques which enable manufacturing and metrology of nanostructures at the very high speeds, accuracies and reliabilities required for industrial applications.

TNO has built EBL2; a facility for EUV exposure testing and surface analysis. EBL2 is capable of testing EUV optics, EUV photomasks, pellicles, and other components under controlled conditions, relevant to EUV scanner and source operation at all foreseen source power nodes. The system consists of an EUV beam line coupled to an X-ray Photoelectron Spectroscopy system by an automated sample handler. The current contribution reports on the results of the qualification testing of the EUV beam line. Topics investigated include handling and position control, thermal management, a relevant gas environment, EUV irradiation and metrology, and first EUV exposures.

By end of 2017 there will be more than 8.4 billion connected devices (Gartner 2017). This means for the first time, Internet of Things (IoT) devices will outnumber the world’s population. In 2020, the number of connected devices will increase to more than 20 billion. This means nearly every devices we own or can imagine will be connected to the Internet. The range is from our mobile phones, wearables, home appliances to even our cities. This full integration of data can have an unprecedented impact in our society by better management of water, energy, transportation and safety, and reaching fully sustainable cities. Growth in IoT scales up the demands for more powerful and energy efficient nanodevices. To enable the power and efficiency demand, 1) the device dimensions are shrinking to atomic dimensions and 2) 3D nanoarchitectures have been introduced to achieve new functionalities and to make optimum use of the available space. However, the technologies currently used for production and quality control approach physical boundaries and will no longer be technologically or economically feasible. As a result of both challenges breakthroughs in manufacturing and metrology methods for (3D) nanoarchitectures are required. TNO’s early research program (ERP) 3D Nanomanufacturing, in close collaboration with its industrial and academic partners have established an innovation ecosystem, to bring solutions for nanomanufacturing and nanometrology challenges. Thanks to our industrial partners, the program has a clear long-term focus on real industrial challenges. The solutions are being developed in close collaborations between our academic partners for low Technical Readiness Levels (TRL) and TNO for developing the technology to an acceptable level to be taken over by industry; in short tackling the very high technical risks. Similar to last three years, again this year we organize the Nanomanufacturing Dissemination Workshop. One of the unique and valuable dimensions to this dissemination workshop is the way it brings industrial and academic world together. The workshop disseminates the technical developments which were achieved every year. Our internationally renowned speakers will present the latest achievements in the field and describe the upcoming challenges. Following that, several oral contributions will present the recent developments in this program. Moreover, the detail of the developments will be discussed and presented by poster presentations. This proceeding includes the Keynote and invited talks, oral contributions of the program and more than 50 poster presentations. The reader will discover that both industry challenges and possible solutions are being presented in this proceeding. Finally, we would like to express our deep appreciation to our invited speakers, Dr. Urs Duerig, Prof. Willem Vos, Prof. Paul Koenraad, Dr. Stefan Witte and Dr. Jason Benkoski.

By end of 2017 there will be more than 8.4 billion connected devices (Gartner 2017). This means for the first time, Internet of Things (IoT) devices will outnumber the world’s population. In 2020, the number of connected devices will increase to more than 20 billion. This means nearly every devices we own or can imagine will be connected to the Internet. The range is from our mobile phones, wearables, home appliances to even our cities. This full integration of data can have an unprecedented impact in our society by better management of water, energy, transportation and safety, and reaching fully sustainable cities. Growth in IoT scales up the demands for more powerful and energy efficient nanodevices. To enable the power and efficiency demand, 1) the device dimensions are shrinking to atomic dimensions and 2) 3D nanoarchitectures have been introduced to achieve new functionalities and to make optimum use of the available space. However, the technologies currently used for production and quality control approach physical boundaries and will no longer be technologically or economically feasible. As a result of both challenges breakthroughs in manufacturing and metrology methods for (3D) nanoarchitectures are required. TNO’s early research program (ERP) 3D Nanomanufacturing, in close collaboration with its industrial and academic partners have established an innovation ecosystem, to bring solutions for nanomanufacturing and nanometrology challenges. Thanks to our industrial partners, the program has a clear long-term focus on real industrial challenges. The solutions are being developed in close collaborations between our academic partners for low Technical Readiness Levels (TRL) and TNO for developing the technology to an acceptable level to be taken over by industry; in short tackling the very high technical risks. Similar to last three years, again this year we organize the Nanomanufacturing Dissemination Workshop. One of the unique and valuable dimensions to this dissemination workshop is the way it brings industrial and academic world together. The workshop disseminates the technical developments which were achieved every year. Our internationally renowned speakers will present the latest achievements in the field and describe the upcoming challenges. Following that, several oral contributions will present the recent developments in this program. Moreover, the detail of the developments will be discussed and presented by poster presentations. This proceeding includes the Keynote and invited talks, oral contributions of the program and more than 50 poster presentations. The reader will discover that both industry challenges and possible solutions are being presented in this proceeding. Finally, we would like to express our deep appreciation to our invited speakers, Dr. Urs Duerig, Prof. Willem Vos, Prof. Paul Koenraad, Dr. Stefan Witte and Dr. Jason Benkoski.

By end of 2017 there will be more than 8.4 billion connected devices (Gartner 2017). This means for the first time, Internet of Things (IoT) devices will outnumber the world’s population. In 2020, the number of connected devices will increase to more than 20 billion. This means nearly every devices we own or can imagine will be connected to the Internet. The range is from our mobile phones, wearables, home appliances to even our cities. This full integration of data can have an unprecedented impact in our society by better management of water, energy, transportation and safety, and reaching fully sustainable cities. Growth in IoT scales up the demands for more powerful and energy efficient nanodevices. To enable the power and efficiency demand, 1) the device dimensions are shrinking to atomic dimensions and 2) 3D nanoarchitectures have been introduced to achieve new functionalities and to make optimum use of the available space. However, the technologies currently used for production and quality control approach physical boundaries and will no longer be technologically or economically feasible. As a result of both challenges breakthroughs in manufacturing and metrology methods for (3D) nanoarchitectures are required. TNO’s early research program (ERP) 3D Nanomanufacturing, in close collaboration with its industrial and academic partners have established an innovation ecosystem, to bring solutions for nanomanufacturing and nanometrology challenges. Thanks to our industrial partners, the program has a clear long-term focus on real industrial challenges. The solutions are being developed in close collaborations between our academic partners for low Technical Readiness Levels (TRL) and TNO for developing the technology to an acceptable level to be taken over by industry; in short tackling the very high technical risks. Similar to last three years, again this year we organize the Nanomanufacturing Dissemination Workshop. One of the unique and valuable dimensions to this dissemination workshop is the way it brings industrial and academic world together. The workshop disseminates the technical developments which were achieved every year. Our internationally renowned speakers will present the latest achievements in the field and describe the upcoming challenges. Following that, several oral contributions will present the recent developments in this program. Moreover, the detail of the developments will be discussed and presented by poster presentations. This proceeding includes the Keynote and invited talks, oral contributions of the program and more than 50 poster presentations. The reader will discover that both industry challenges and possible solutions are being presented in this proceeding. Finally, we would like to express our deep appreciation to our invited speakers, Dr. Urs Duerig, Prof. Willem Vos, Prof. Paul Koenraad, Dr. Stefan Witte and Dr. Jason Benkoski.

Further scaling and miniaturization of nanodevices (nanoelectronics, Quantum devices bio-nano devices for healthcare) brings major manufacturing, metrology and characterization challenges that cannot be met anymore by current techniques. The High Volume Manufacturing industry requires, more than ever, metrology methods that routinely measure structural and material parameters at atomic level in nm-sized structures, with atomic precision, with high throughput, for an ever increasing set of combinations of new materials in 3D structures. The research program 3D nanomanufacturing will enable the transition from 2D to 3D nanostructures, that will support the need for ever more powerful devices. The focus is on the development of instruments and techniques which enable manufacturing and metrology of nanostructures at the very high speeds, accuracies and reliabilities required for industrial applications.

The LISA Optical Stability Characterization project is part of the LISA CTP activities to achieve the required TRL level for all of the LISA technologies used. In 2012 the LISA mission was reformulated and transferred to the New Gravitational Observatory (NGO), which has similar performance requirements. This activity targets the demonstration of the Telescope Assembly (TA), with a structure based on CFRP technology, to show that total deformations corresponding to a system CTE of 10-7 K-1 can be passively achieved, i.e., without a dedicated thermal control. In addition it is required to prove that the structure exhibits highly predictable mechanical distortion characteristics when cooling down to ˗90°C, during outgassing in space and when going from 1g environment to 0g. A dedicated test setup is designed and realized to allow monitoring dimensional variations of the TAstructure using three interferometers, while varying the temperature in a thermal vacuum chamber. Critical parameters of the verification setup are the length metrology accuracy in thermal vacuum and the stability. For practical application also a high degree of flexibility and ease of operation are required. The test programme includes CTE measurements and thermal gradient characterization of the Telescope Assembly. This paper describes the current development status of the telescope structure. Previously the test facilities as well as the first test results were presented. In this paper the results of these thermal vacuum experiments are described. These results then are analyzed using FEM analysis and compared to the predicted performance. From this comparison modifications are derived to finely trim the thermo-elastic behavior of the telescope assembly. A second thermal vacuum experiment is performed to validate the improved thermo-elastic performance of this off-axis telescope. A third experiment has been performed, which confirms the findings of the second test.

Acoustic underwater communication is an enabler for the use of autonomous underwater vehicles (AUVs). AUVs can operate in acoustically challenging environments, e.g., near offshore platforms and in harbours. To realize robust underwater communication in such environments, the propagation conditions need to be properly understood. In this paper, the performance of underwater acoustic communication in shallow water harbour environments is investigated. To perform our investigation, channel soundings (i.e., empirical channel impulse responses) captured in the Port of East-Vlissingen (The Netherlands) are employed. In particular, it is investigated how the increase of acoustic reverberation caused by reflections from physical structures in a harbour (e.g., quay walls, jetties, piers) affects the underwater acoustic communication performance. The empirical reverberation obtained from the channel soundings is compared with the modelled two-dimensional equivalent in order to make a distinction between bottom-surface paths and reflections from physical structures in the harbour. The collected channel soundings and their analysis are necessary for the development of novel modulation methods and provide useful input for an improved understanding of the acoustic propagation conditionsin harbour environments. The findings in this paper can be used by future tools for autonomous underwater operations.

Acoustic Mitigation Devices (AMDs) are used to deter marine mammals from construction sites, in order to prevent hearing injury by offshore pile driving noise. To estimate the distance at which two AMDs designed as ‘seal scarers’ (Ace Aquatec and Lofitech) are detected by harbor porpoises, the 50% hearing detection thresholds for playbacks of recordings of the AMD sounds were assessed. Both became audible at a received broadband sound pressure level (SPL) of 55 dB re 1 µPa. The effect of the AMDs on porpoise behavior was quantified at three SPLs determined during a pre-test: one which just did not cause a behavioral change, one which caused a small change in surfacing and swimming pattern, and one which caused the harbor porpoise to swim away from the transducers. The corresponding mean received SPLs in the pool were respectively: Ace Aquatec: 77, 117, and 139 dB re 1 µPa; and: Lofitech: 91, 121, and 151 dB re 1 µPa. As the mean received SPL increased, greater displacement occurred, and higher numbers of surfacings and increased swimming speed occurred in test periods than in associated baseline periods. By combining these results with the source level, the current local propagation conditions and the background noise, the deterring distance at sea for the AMDs can be calculated.

Threat detection is a challenging problem, because threats appear in many variations and differences to normal behaviour can be very subtle. In this paper, we consider threats on a parking lot, where theft of a truck’s cargo occurs. The theft takes place in very different forms, in the midst of many people who pose no threat. The threats range from explicit, e.g., a person attacking the truck driver, to implicit, e.g., somebody loitering and then fiddling with the exterior of the truck in order to open it. Our goal is a system that is able to recognize a threat instantaneously as they develop. Typical observables of the threats are a person’s activity, presence in a particular zone, and the trajectory. The novelty of this paper is an encoding of these threat observables in a semantic, intermediate-level representation, based on low-level visual features that have no intrinsic semantic meaning themselves. The semantic representation encodes the notions of trajectories, zones and activities. The aim of this representation is to bridge the semantic gap between the low-level tracks and motion and the higher-level notion of threats. In our experiments, we demonstrate that our semantic representation is more descriptive for threat detection than directly using low-level features. We find that a person’s activities are the most important elements of this semantic representation, followed by the person’s trajectory. The proposed threat detection system is very accurate: 96.6% of the tracks are correctly interpreted, when considering the temporal context. *

Maintenance operations on ITER tokamak components will be largely performed by remote handling. In previous work it was shown that representative maintenance tasks could be performed significantly faster with direct visual feedback than with camera feedback. In post-test interviews, operators indicated that they regarded the lack of 3D perception as the primary factor hindering their performance. This paper discusses various techniques to improve depth perception in teleoperation, including stereo vision, head tracking, virtual camera views and depth gauges. The most promising techniques were tested. Performance metrics included time-to-complete, path analysis and operator work-load. In a first experiment, artificial depth gauges views were tested in a 1:1 scale hardware testbed with mechanical master-slave manipulators handled by experienced operators. Robust real-time image processing was achieved with marker-based objects. The simple depth gauge and graphical overlay did not significantly improve task performance. Operators commented on their view of the task being “obstructed” by the graphical overlay, and the depth gauge was judged not very informative. In a second experiment, real time tracking was combined with VR display including stereo and head tracking. While stereo was found to improve the task performance significantly over the 1 camera (mono) condition, head tracking unexpectedly did not.

The kinetics and the mechanism of reduction of a RuO2(110) film, grown thermally on a Ru(0001) surface, has been studied in the temperature range of 60-200 °C by using an atomic hydrogen flux of 2 × 1019 at. H m-2 s-1. The reduction kinetics is dominated by the creation of oxygen vacancies at the surface (Vbr) and bulk lattice positions (V3f), and by the subsequent diffusion of subsurface oxygen species (O3f) to these vacancies. The activation energy associated with this reduction process equals 0.43 eV. At 200 °C, about 10 H atoms are required for the removal of an oxygen atom from the RuO2 lattice. This value is about an order of magnitude lower when compared with the reduction of RuO2 by molecular hydrogen under similar conditions. Moreover, the reduction proceeds at least 14 times faster when using highly reactive atomic hydrogen species. © 2013 Elsevier B.V. All rights reserved.

Reliable localization of marine mammals using towed arrays is often required for mitigation, population density estimates, and bioacoustics research. The accuracy of the range estimates using towed arrays is often not well quantified. Triangulation methods using multiple hydrophones allow for fast range estimates but are sensitive to the species type, location of the animal with respect to the array, sound propagation conditions, and array stability. A simple model is presented that is used to estimate the range accuracy of towed arrays for different vocalizations and is compared to measured range accuracies of sperm whale clicks recorded with a 15m baseline towed array. The ranging performance is particularly sensitive to hydrophone position errors which are found to dominate. Hydrophone position errors could be estimated using heading sensors placed in the array and are taken into account in the model. A good agreement is found between the empirical range errors and theoretically predicted ones. Extrapolation of the model to other species suggests that species emitting high frequency clicks and calls can be localized from distances out to a few kilometers with a baseline of 15 m, but baleen whales transmitting low frequency calls require longer baselines to obtain range estimates. VC 2013 Acoustical Society of America.

Well-calibrated scaling relations between the observable properties and the total masses of clusters of galaxies are important for understanding the physical processes that give rise to these relations. They are also a critical ingredient for studies that aim to constrain cosmological parameters using galaxy clusters. For this reason much effort has been spent during the last decade to better understand and interpret relations of the properties of the intra-cluster medium. Improved X-ray data have expanded the mass range down to galaxy groups, whereas SZ surveys have openened a new observational window on the intracluster medium. In addition,continued progress in the performance of cosmological simulations has allowed a better understanding of the physical processes and selection effects affecting the observed scaling relations. Here we review the recent literature on various scaling relations, focussing on the latest observational measurements and the progress in our understanding of the deviations from self similarity., 38 pages. Review paper. Accepted for publication in Space Science Reviews (eds: S. Ettori, M. Meneghetti). This is a product of the work done by an international team at the International Space Science Institute (ISSI) in Bern on "Astrophysics and Cosmology with Galaxy Clusters: the X-ray and Lensing View"

A type-III PLL is used to generate linear frequency ramps with 386 kHz RMS frequency error in L-band (3088 kHz in X-band) and 10% fractional bandwidth. Pulse durations can be as low as 10 μs without performance degradation. The system covers the L-, S-, C- and X-bands. A programmable output driver delivering -17.9 to +4.9 dBm differentially is included on chip. The system is fully integrated using a 250 nm SiGe BiCMOS process. © 2013 IEEE.

We consider the problem of target detection from a set of Compressed Sensing (CS) radar measurements corrupted by additive white Gaussian noise. We propose two novel architectures and compare their performance by means of Receiver Operating Characteristic (ROC) curves. Using asymptotic arguments and the Complex Approximate Message Passing (CAMP) algorithm, we characterize the statistics of the l1-norm reconstruction error and derive closed form expressions for both the detection and false alarm probabilities of both schemes. Of the two architectures, we demonstrate that the best performing one consists of a reconstruction stage based on CAMP followed by a detector. This architecture, which outperforms the l1-based detector in the ideal case of known background noise, can also be made fully adaptive by combining it with a conventional Constant False Alarm Rate (CFAR) processor. Using the state evolution framework of CAMP, we also derive Signal to Noise Ratio (SNR) maps that, together with the ROC curves, can be used to design a CS-based CFAR radar detector. Our theoretical findings are confirmed by means of both Monte Carlo simulations and experimental results. © 2012 IEEE.

The ITER core CXRS diagnostic system collects the light emitted from the interaction of the diagnostic neutral beam with the core plasma and guides it via a mirror labyrinth through the upper port plug #3 towards a fiber bundle, which then transmits the light into a set of spectrometers for spectral analysis. In order to test the accessibility of the special parameter range required for the ITER measurement, a prototype spectrometer was built and operated successfully at the TEXTOR tokamak. In addition to the He/Be, C/Ne and H/D/T regular spectral channels, a fluctuation beam emission spectroscopy (BES) system has been integrated to measure core MHD activity, and validate corresponding ITER simulation results. The fluctuation system can be operated as an alternative to the spectral BES measurement, and has 8 spatial channels sampled at 2 MHz. In this paper, we present details of the fluctuation BES system and its interface to the ITER prototype spectrometer along with simulation and measurement results at TEXTOR. We show that the measurement fully confirms the simulation results on achievable photon current at the detector and on the signal to noise ratio. Keywords ITER; MHD; CXRS; Fluctuation; Beam emission; TEXTOR; Validation

A wideband, wide-scan phased array of connected dipoles has been designed and fabricated. Measured results from a 7 7 prototype demonstrator are presented for experimental validation. In order to avoid common-mode resonances that typically affect this type of array, loop-shaped transformers are included in the feed network. The common-mode rejection implemented by these transformers allow maintaining the cross-polarization levels to values lower than 10 dB over a 30% relative bandwidth, for an elevation angle up to 45 in all azimuth planes. The array exhibits a measured voltage standing-wave ratio (VSWR) lower than 2.5 from 3 to 5 GHz for broadside radiation. The VSWR maintains levels lower than 3 within a scan volume of 45 from broadside in all planes.

Electrotaxis is the cell migration in the presence of an electric field (EF). This migration is parallel to the EF vector and overrides chemical migration cues. In this paper we introduce a mathematical model for the electrotaxis in osteoblastic cells. The model is evaluated using different EF strengths and different configurations of both electrical and chemical stimuli. Accordingly, we found that the cell migration speed is described as the combination of an electrical and a chemical term. Cell migration is faster when both stimuli orient cell migration towards the same direction. In contrast, a reduced speed is obtained when the EF vector is opposed to the direction of the chemical stimulus. Numerical relations were obtained to quantify the cell migration speed at each configuration. Additional calculations for the cell colonization of a substrate also show mediation of the EF strength. Therefore, the term electro-osteoconduction is introduced to account the electrically induced cell colonization. Since numerical results compare favorably with experimental evidence, the model is suitable to be extended to other types of cells, and to numerically explore the influence of EF during wound healing.

The generation and decomposition rate of volatile tin hydrides (SnH 4) was determined with two quartz crystal microbalances (QCM). One crystal covered with Sn was exposed to a known flux of atomic hydrogen (H) to generate SnH 4. Another Au coated QCM was placed opposite to the Sn coated surface to determine the decomposition characteristics of the generated SnH 4. The chemical nature and the morphology of the deposits were investigated with X-ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscopy (SEM), respectively. © 2012 Elsevier B.V. All rights reserved.

To reduce the amount of data transfer in networked systems, measurements are usually taken only when an event occurs rather than at each synchronous sample instant. However, this complicates estimation problems considerably, especially in the situation when no measurement is received anymore. The goal of this paper is therefore to develop a state estimator that can successfully cope with event based measurements and attains an asymptotically bounded error-covariance matrix. To that extent, a general mathematical description of event sampling is proposed. This description is used to set-up a state estimator with a hybrid update, i.e., when an event occurs the estimated state is updated using the measurement, while at synchronous instants the update is based on knowledge that the sensor value lies within a bounded subset of the measurement space. Furthermore, to minimize computational complexity of the estimator, the algorithm is implemented using a sum of Gaussians approach. The benefits of this implementation are demonstrated by an illustrative example of state estimation with event sampling.

In May 2011, the Grand Cooperative Driving Challenge (GCDC) was held, providing the possibility for teams to develop and compare their cooperative driving solutions in a competitive setting. The challenge was organized to further accelerate developments in the area of cooperative driving. Nine international teams challenged each other to handle both an urban and a highway scenario. These scenarios have been chosen such that the performance of the implementation of cooperative adaptive cruise control of each participant can be judged. Evaluation of the vehicle behavior has been performed by means of video-based roadside units, installed at the test site in The Netherlands, that is capable of tracking the individual vehicles, in addition to the information obtained through wireless communication. Judgement criteria include both macroscale criteria, such as platoon length and traffic light throughput, and individual criterion, like string stability. Most teams performed well, although clear differences in performance and reliability could be observed. The GCDC showed that it is possible to cooperatively drive with heterogeneous systems. It is envisioned to make the GCDC a regular event and to further extend the active role of roadside communication units, as well as include automated lateral vehicle control.

This article focuses on the problem of fusing two prior Gaussian estimates into a single estimate, when the correlation is unknown. Existing solutions either lead to a conservative fusion result, as the chosen parametrization focuses on the fusion formulas instead of correlations, or they are computationally expensive. The contribution of this article is a novel parametrization, in which the correlation is explicitly characterized a priori to deriving the fusion formulas. Then, maximizing the correlation ensures that the fusion result is based on independent parts of the prior estimates and, simultaneously, addresses the fact that the correlation is unknown. In addition, a guaranteed improvement of the accuracy after fusion is attained. An illustrative example demonstrates the benefits of the proposed method compared to an existing fusion method.

Chatter is an instability phenomenon in machining processes which limits productivity and results in inferior workpiece quality, noise and rapid tool wear. The increasing demand for productivity in the manufacturing community motivates the development of an active control strategy to shape the chatter stability boundary of manufacturing processes. In this work a control methodology for the high-speed milling process is developed that alters the chatter stability boundary such that the area of chatter-free operating points is increased and a higher productivity can be attained. The methodology developed in this paper is based on a robust control approach using μ-synthesis. Hereto, the most important process parameters (depth of cut and spindle speed) are treated as uncertainties to guarantee the robust stability (i.e., no chatter) in an a priori specified range of these process parameters. Effectiveness of the proposed methodology is demonstrated by means of illustrative examples. © 2011 IEEE.

Weather Research and Forecasting (WRF) model predictions using different boundary layer schemes and horizontal grid spacings were compared with observational and numerical large-eddy simulation data for conditions corresponding to a dry atmospheric convective boundary layer (CBL) over the southern Great Plains (SGP). The first studied case exhibited a dryline passage during the simulation window, and the second studied case was used to examine the CBL in a post-cold-frontal environment. The model runs were conducted with three boundary layer parameterization schemes (Yonsei University, Mellor–Yamada–Janjić, and asymmetrical convective) commonly employed within the WRF model environment to represent effects of small-scale turbulent transport. A study domain was centered over the Atmospheric Radiation Measurement Program SGP site in Lamont, Oklahoma. Results show that near-surface flow and turbulence parameters are predicted reasonably well with all tested horizontal grid spacings (1, 2, and 4 km) and that value added through refining grid spacing was minimal at best for conditions considered in this study. In accord with this result, it was suggested that the 16-fold increase in computing overhead associated with changing from 4- to 1-km grid spacing was not justified. Therefore, only differences among schemes at 4-km spacing were presented in detail. WRF model predictions generally overestimated the contribution to turbulence generation by mechanical forcing over buoyancy forcing in both studied CBL cases. Nonlocal parameterization schemes were found to match observational data more closely than did the local scheme, although differences among the predictions with all three schemes were relatively small.

After a disaster such as an earthquake or tsunami it is important to know quickly the dimensions of the damage to human relief work and crisis management. To study the utility of high-resolution radar damage-assessment for this purpose, pre- and post-seismic TerraSAR-X and Cosmo-SkyMed data of the earthquake in Haiti on 12 January 2010 were compared with the results of visual damage assessment, carried out in the framework of the Post Disaster Needs Assessment and Recovery Framework (PDNA). Studied were grid-based methods estimating the average damage, and detailed methods up to building level. On a grid-scale of 200 m, regression analysis of the average normalized difference between pre- and post-seismic data, and the PDNA, results in an average correlation coefficient of up to 0.49 for medium density built-up in TerraSAR-X. Correlation of the shanty areas is lower than for high density built-up. Industrial areas are excluded because of the continuous activity not related to the earthquake. Detailed damage assessment at building level is less hopeful because the correlation per building is low, though improvement is expected from adding information on the boundaries of buildings, if available. To summarize, grid-based average radar damage assessment in the first days after an earthquake event looks promising, but the type of built-up and the period of time between the acquisitions have to be taken into account. For a more detailed assessment on the long term, in working on reconstruction, it is better to rely on other sources.

We present the design and first field trial results of an all-day all-weather enhanced and synthetic-fused multi-band colour night vision surveillance and observation system. The system augments a fused and dynamic three-band natural-colour night vision image with synthetic 3D imagery in real-time. The night vision sensor suite consists of three cameras, sensitive in, respectively, the visual (400–700 nm), the near-infrared (NIR, 700–1000 nm) and the long-wave infrared (LWIR, 8–14 mm) bands of the electromagnetic spectrum. The optical axes of the three cameras are aligned. Image quality of the fused sensor signals is enhanced in real-time through dynamic noise reduction, super resolution and local adaptive contrast enhancement. The quality of the LWIR image is enhanced through scene-based non-uniformity correction. The visual and NIR signals are used to represent the fused multi-band night vision image in natural daytime colours, using the Colour-the-Night colour remapping technique. Colour remapping can also be deployed to enhance the visibility of thermal targets that are camouflaged in the visual and NIR range of the spectrum. The dynamic false-colour night-time images are augmented with corresponding synthetic 3D scene views, generated in real-time using a geometric 3D scene model in combination with position and orientation information supplied by the Global Positioning System and inertial sensors of the system. Initial field trials show that this system provides enhanced situational information in various low-visibility conditions.

RF arc detection is a key operational and safety issue for ICRF systems. Dedicated measurements on a RF test-stand were made in order to characterize the optical signature of RF arcs (time and spectrum) to assess the potential of optical arc detection on ICRF systems. Time-resolved intensity measurements were carried out using high-speed Si photodetectors with different bandpass filters. The rise time of the arc emission, the light intensity and the time evolution of the arc under different pressure conditions are discussed. Spectral signature of the arcs was obtained using spectrometers in the visible and UV range. It is shown that the arc emission spectrum is independent of the gas pressure and that it is mainly dominated by the stainless steel components of the test bench. The results of the RF arc optical characterization is discussed with a view on the implementation of an optical arc detection system for an ICRF antenna on a fusion machine, both for sections viewing the plasma light as for private vacuum sections. © 2011 Pierre Dumortier Published by Elsevier B.V. All rights reserved.

New optical configurations for the ITER core CXRS system offer the possibility of longer ducts between the first mirror and the plasma. This has led to a renewed optimization of the availability. using a simple model of the degradation of the first mirror that starts with the conditions of (a) the required measurement performance and (b) the geometry of the port plug. It is found that for a fully passive system the design should strive for the longest duct length possible. Given known data, this will result in a diagnostic lifetime still substantially shorter than ITER lifetime. When an option of cleaning the first mirror is introduced (assuming this is a feasible option) the optimum is less straightforward, because the lifetime of the second mirror then also becomes important. The optimum then depends on the ratio between the cleaning interval and the ITER lifetime. Options are presented for various sets of assumptions. Finally practical limitations of supporting subsystems (cleaning system, shutter, calibration system) may influence the final design. Examples of such limitations with their impact are presented. (C) 2011 Published by Elsevier B.V.

Sparse signal representation (SSR) is considered to be an appealing alternative to classical beamforming for direction-of-arrival (DOA) estimation. For wideband signals, the SSR-based approach constructs steering matrices, referred to as dictionaries in this paper, corresponding to different frequency components of the target signal. However, the SSR-based approach is subject to ambiguity resulting from not only spatial aliasing, just like in classical beamforming, but also from the over-completeness of the dictionary, which is typical to SSR. We show that the ambiguity caused by the over-completeness of the dictionary can be alleviated by using multiple measurement vectors. In addition, by considering the uniform linear array (ULA) structure, we argue that if the target signal contains at least two frequencies, whose absolute difference phrased in wavelengths is larger than twice the array spacing, the spatial aliasing corresponding to these frequencies will be completely distinct. These properties enable us to adapt the existing l1 algorithms to extract the target DOAs without ambiguity.

The Health Council of the Netherlands (HCN) and other organisations hold the basic assumption that induced electric current and the generation and absorption of heat in biological material caused by radiofrequency electromagnetic fields are the only causal effects with possible adverse consequences for human health that have been scientifically established to date. Hence, the exposure guidelines for the 10 MHz-10 GHz frequency range are based on avoiding adverse effects of increased temperatures that may occur of the entire human body at a specific absorption rate (SAR) level above 4 W/kg.During the workshop on Thermal Aspects of Radio Frequency Exposure on 11-12 January 2010 in Gaithersburg, Maryland, USA, the question was raised whether there would be a practical advantage in shifting from expressing the exposure limits in SAR to expressing them in terms of a maximum allowable temperature increase. This would mean defining adverse time-temperature thresholds. In this paper, the HCN discusses the need for this, considering six points: consistency, applicability, quantification, causality, comprehensibility and acceptability.The HCN concludes that it seems unlikely that a change of dosimetric quantity will help us forward in the discussion on the scientific controversies regarding the existence or non-existence of non-thermal effects in humans following long duration, low intensity exposure to electromagnetic fields. Therefore, the HCN favours maintaining the current approach of basic restrictions and reference levels being expressed as SAR and in V/m or µT, respectively.Read More: http://informahealthcare.com/doi/abs/10.3109/02656736.2010.534528

Connected arrays constitute the only family of antenna arrays for which the spectral Green's Functions have been derived analytically. This formalism is extended here to the receiving case. When the arrays are assumed to be infinitely extended and periodically excited, rigorous equivalent networks can be derived to represent the electromagnetic field distribution in transmission and/or reception. These equivalent networks are based on Green's functions, thus each components can be associated with a specific physical wave mechanism. Moreover, all components are evaluated analytically. The total power transmitted, received and/or scattered by a connected array with and without backing reflector is discussed. The full efficiency of an array with backing reflector is demonstrated and explained. Finally, measurements from a dual-band connected array prototype validate the equivalent circuit representation.

Charged particle microscopes have been used extensively for the creation of nanostructures. As a subset of the techniques for this, the process of beam-induced chemistry offers almost endless flexibility for both additive (by beam-driven precursor deposition) and subtractive (by beam-catalyzed etching) processing. A recent review article makes it evident simply by its massive page count the number of materials that have been used to deposit a variety of conductive, insulating, magnetic, photonic, and other structures. To take advantage of these capabilities, though, the nanoarchitect must select the correct settings for a large number of parameters. One key figure of interest is the size of features that can be written by deposition of conducting material: how small can we go? Process development is complex, however: a standard beam-induced deposition process using the system described below calls for the control of sixteen different parameters! Several of these are used to set the flow of the reactant, several are required for defining the particle beam, and yet another set of parameters call out the routine by which the beam is scanned over the pattern of interest. In the end, the result provides just one recipe for one chemistry with one beam type. The wide scatter of reported outcomes in the review article mentioned above indicates the complexity of the problem, where each result given can be considered just a snapshot of one small corner of the parameter space. Our goal here is to apply a quantitative optimization methodology for the determination of beam chemistry processes in the helium ion microscope (HIM). In this article, we discuss efforts toward finding the minimum obtainable line width and gap width between line pairs of deposited platinum lines and giving a predictive formulation of the same.

We have investigated experimentally the pulse train (mode beating) stability of a monolithic mode-locked multi-section quantum-dot laser with an added passive auxiliary optical fiber cavity. Addition of the weakly coupled (∼ - 24 dB) cavity reduces the current-induced shift dv / dl of the principal peak in the RF spectrum (the effective pulse repetition frequency) by more than an order of magnitude, from -39.5 to - 2.3 kHz/mA. The rms timing jitter of the pulse train is simultaneously reduced from 1.4 to 0.9 ps. © 2009 IEEE.

This paper describes numerical and experimental results of beamforming algorithms for generation of directional sound. The intended application is a sound source for cars with the objective to warn vulnerable road users while minimising noise pollution. Nowadays, sensors exist which are able to reveal the position of the vulnerable road users, which information can be used by the warning signal generator. Based on this information, the signal generator is designed to generate the specified warning signal at the location of the vulnerable road user while the acoustic response at other locations is minimised. The directional sound beam was realised with an array of controlled acoustic moving coil sources. The paper compares different methods to generate the sound beam and investigates their effectiveness for this application by simulation and experimental results. The robustness under realistic conditions in simulations and in initial real-time experiments on a car are discussed.

The impedance of an antenna changes heavily with changing EM environments, while RF power amplifiers (PAs) are optimized for driving a well-defined load impedance. As a solution, switchable matching networks are used in automatic antenna tuners to match the antenna impedance to (about) the desired PA load impedance. This paper presents a theoretical treaty of the minimum number of required states for switchable matching networks to achieve sufficient matching from a certain load VSWR to a sufficiently low input VSWR. First for an arbitrary passive lossless switchable matching network, the mathematical minimum required number of states as a function of the required input VSWR and of the required load VSWR is derived. Several variants are analyzed and benchmarked: single-stage one-ring configuration, single-stage two-ring configuration, two-stage one-ring configuration and three-stage one-ring configuration showing that single-ring configurations are optimum. An extension towards the required number of states for lossy matching networks is also provided.

Acoustic mitigation devices (AMDs) are used to deter marine mammals from construction sites to prevent hearing injury by offshore pile-driving noise. In order to quantify the distance at which AMDs designed as ‘seal scarers’ are detected by seals, the 50% hearing thresholds for playbacks of their sounds were determined. The broadband hearing threshold sound pressure levels (SPLs) of two harbor seals for signals from two AMDs were similar (63–69 dB re 1 μPa, rms). Effects of the AMDs on the seals’ behavior were quantified at three SPLs: one which just did not cause behavioral changes, one which caused one of the seals to haul out occasionally, and one which caused one of the seals to haul out more than 10% of the time. The corresponding mean received SPLs were, respectively, Ace Aquatec: 109, 124, and 134 dB re 1 μPa, rms; Lofitech: 128, 133, and 138 dB re 1 μPa, rms. Thus at similar received levels, the Ace Aquatec seems more effective than the Lofitech in deterring harbor seals. Detection and behavioral response distances of the AMD sounds for harbor seals at sea can be estimated by combining the results from the present study with data on AMD source levels, propagation conditions, and background noise levels near construction sites.

For conservation purposes, it is important to evaluate potential population consequences of noise disturbance. Based on maximum reported sound levels of no response to sonar, a mathematical model is used to predict the potential risk to the population of herring (Clupea harengus) when these levels are exceeded. Results show that risk varies with season depending on density of fish. During widespread feeding, the risk of any population consequences is loweven at sonar source levels up to 235 dB (re 1 mPa m) and exercise durations exceeding 24 h at sonar frequencies 1–2 kHz. The risk of population effects increases in periods when the population aggregates, but given that our response estimates are conservative, it seems unlikely that today’s naval sonar activity will lead to population consequences in Atlantic herring.