16,590 research outputs found
Recent Results From the EU POF-PLUS Project: Multi-Gigabit Transmission Over 1 mm Core Diameter Plastic Optical Fibers
No full textRecent activity to achieve multi-gigabit transmission over 1 mm core diameter graded-index and step-index plastic optical fibers for distances up to 50 meters is reported in this paper. By employing a simple intensity-modulated direct-detection system with pulse amplitude or digital multi-tone modulation techniques, low-cost transceivers and easy to install large-core POFs, it is demonstrated that multi-gigabit transmission up to 10 Gbit/s over 1-mm core diameter POF infrastructure is feasible. The results presented in this paper were obtained in the EU FP7 POF-PLUS project, which focused on applications in different scenarios, such as in next-generation in-building residential networks and in datacom applications
Harmonization of land registry in Europe
No full textAn increase in cross-border transactions of immovable property within the European Union puts a demand for easy access to the information of the national land administrations of the member states. The European Union Land Information System (EULIS) project brings together the registrations of eight European jurisdictions in one portal. In this way it provides cross-border access to information about the rights on real estate, using the information in thecomputerized databases of the participating land registries. The EULIS project is the first step towards a more transparent system of real estate transactions. The next logical step, from the viewpoint of international accessibility of the information, is that the national land registries within the united Europe will be harmonized or even integrated in one European land registry or administration.In order to promote cross-border transactions and to facilitate the European mortgage market the authors suggest the introduction of a common way of land registration, in addition to the existing national land registrations: the EuroTitle system. This is a challenging concept, which may bring the required uniformity of land registration in Europe. This approach is in the beginning stages of development and the legal and organisational consequences need to be further explored and developed in order to assess the feasibility of the introduction of such a concept in European land registry.OLD Geo-information and Land Developmen
Employing M1 direct calibration/de-embedding approaches for large signal model validation at mm-wave frequencies
No full textIn this contribution, we employ direct calibration/de-embedding approaches to validate the large signal device model of state-of-the-art HBTs and CMOS technologies operating in the mm-wave frequency band WR6. The capability of placing the first tier calibration reference plane in close proximity to the DUT allows the large signal metric to be directly compared with foundry models.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic
The role of access policies on the Development of local SDIs: the Special Role of Utilities
No full textWithin the context of Spatial data infrastructures (SDI) access-to-government-data policies are important for the existence and successful use of the data, and the success of the SDI itself. Many researches have attempted to assess the success of access policies for public sector (geographic) information. Most compare the open access approach of the United States federal government with the cost recovery models in other countries, and conclude that the open access policy is more successful. Consistently, most research recommend nations toconvert cost recovery policies into open access policies. The SDI hierarchy of global, regional, national, state, local and corporate SDIs, however, suggests that success of a specific policy option at one SDI level does not necessarily apply to other levels of SDIs.Therefore, although at first sight the accomplished researches provide convincing evidence for the success of the open access model at the national (or regional) level, they appear to have some deficiencies for application to the local levels of SDIs. The frequently cited researches underestimate the role cost recovery policies may have in the availability of spatial framework data at the local levels of SDI. Through an analysis of the large-scale topographic datasets in three jurisdictions in Europe and two states in the United States, this paper provides insights in the technical and non-technical characteristics of these data, and in the role private or semi-public utilities may play at the local SDI levels. The paper will show that cost recovery policies may be more beneficial for SDI development at the local levels than current research has suggested.OLD Geo-information and Land Developmen
ICEB 2009 Dortmund: International Conference on Extrusion and 3rd Extrusion Benchmark
No full textIn the 2009 Benchmark, a multiple hole die for the simultaneous extrusion of two U shape profiles was designed
(Figure 2, left) in order to produce an effective comparison for different tongue design strategies. The bottom profile was characterized by a standard supporting
shape while the supporting part of the upper profile was deeply shortened (26.95 mm) in order to achieve a measurable die deflection during the process (Figure 2, right). With this configuration, a higher deflection of the upper part of the die with the less supported inner profile
contour was expected, producing a loss of contact in the bearing zones and an alteration of the thermal field at the two exits and as a consequence a difference also in material flow and profile distortions was expected for the two profiles. On the other hand, the U-shape of the profiles
allows the accessibility for laser measuring devices to detect the deflection of the inner tongues along the extrusion
direction, while the length of the U-shape (59.3 mm) provided for an adequate magnification of the die deflection. The die was made of AISI H-13 hot-working tool steel tempered to 45 HRC hardness and built by WEFA, Germany
Dynamic Estimation of Vital Signs with mm-wave FMCW Radar
No full textIn this paper, we propose a method for continuous monitoring of vital signs-in particular, respiration frequency-with a commercial mm-wave radar. The nearly constant frequency (NCF) model is adopted to represent chest displacement due to respiration and simulate radar response. Based on this model, an extended Kalman filter (EKF) based estimator is developed to track the breathing frequency of a person. The impact of dynamic model parameters is investigated in numerical simulation. The possibility to track breathing frequency with the proposed method is demonstrated by experimental data processing. Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Microwave Sensing, Signals & System
A 23-to-29GHz Receiver with mm-Wave N-Input-N-Output Spatial Notch Filtering and Autonomous Notch-Steering Achieving 20-to-40dB mm-Wave Spatial Rejection and -14dBm In-Notch IP1 dB
No full textDigital beamforming receivers (RXs) support MIMO operation and offer great flexibility and accuracy in multi-beam formation and calibration. However, compared with analog phased-array and hybrid systems, due to the absence of any rejection for spatial in-band blockers, the RX/ADC dynamic range and linearity should be high enough to prevent array saturation. Therefore, the use of self-steering spatial notch filters (SNFs) is necessary to aid the digital beamformers and reduce RX/ADC power consumption while strong blockers exist. To address that, the sub-6GHz RXs in [1], [2] synthesize a baseband spatial notch impedance and translate it to RF by passive mixers. However, this technique cannot be directly applied at mm-wave frequencies as the impedance translational performance of the passive mixers degrades significantly. Hence, the mm-wave beamformer in [3] realizes a cascadable SNF at an intermediate frequency (IF). However, the front-end mm-wave components like mixers and phase shifters have to tolerate strong blockers, thus degrading RX linearity. Besides, it uses multiple IF buffers and VGAs for signal scaling and combining, which could be power-hungry if a similar method is adopted to realize a mm-wave SNF. To improve on those limitations, we propose a scalable SNF structure, which (1) suppresses the strongest in-band blocker at mm-wave frequencies, (2) supports N-input-N-output MIMOs, and (3) requires no active blocks except the phase shifters. A two-step autonomous notch-steering technique is also developed to adjust the SNF notch direction power-efficiently and accurately.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic
Experiencing the armed struggle : the Soweto generation and after
No full textIncludes bibliographical references (p. 354-369).This study explores the experiences of the rank-and-file soldiers of Umkhonto we Sizwe and the Azanian People's Liberation Anny. Extensive interviews by the author and other researchers reveal the voices of the soldiers themselves. The African National Congress and Pan African Congress archives at the University of the Western Cape and the University of Fort Hare supplement and verify these oral testimonies, as do some published sources. Most previously published materials about the armed struggle against apartheid have already focused on diplomacy, strategy and tactics, operations, leadership, and human rights abuses to the neglect of the soldiers' actual experiences. This study complements these with significant new oral history materials from the Soweto generation of soldiers and their successors. When dealing with MK, many authors have documented issues of the camp structure in Angola, and operations inside South Africa, so much of this detail is only addressed briefly, leaving space to explore the soldiers' experiences. In the case of APLA, very little has been written on its history, and more detail is provided on these subjects. This study therefore deals with the soldiers' politicisation and motivation for joining the armed struggle, their experiences in leaving South Africa and training in exile, the crises in exile which limited their effectiveness for a time, their return to fight in South Africa, and their difficulties in the "new" South Africa. These materials reveal that vast problems remain facing these veterans of the struggle against apartheid, and that they have the potential, if properly supported and employed, to contribute substantially to the development of present day South Africa. Conversely, if their neglect continues, they also have the potential to bring vast harm to the country. Further use of the investigative tools of oral history, especially if extended to the former soldiers' vernacular languages, is necessary to augment the history of South Africa, and these soldiers' contributions
Effect of porthole design and welding chamber dimensions on material flow and weld deformability of extruded aluminium profiles
No full textAim of the work is to investigate different strategies in balancing material flow during
direct extrusion through porthole dies. Two AA6082 hollow profiles were simultaneously extruded
by a single die with different portholes extrusion ratio, dissimilar welding chambers and different
bearing lengths. A strict process control was realized by measuring thermal conditions in the die by
means of 6 thermocouples and on the profiles by a self calibrating pyrometer for aluminum alloy
applications. Several billets were extruded at different ram speeds (2 to 7 mm/sec) and the effect of
die design on surface quality, profile lengths and thermal field was recorded. The profiles were then
sectioned and the position of the seam welds in the profiles identified and compared also with the
profiles tip
Assessment of the Thermomechanical Behavior and Microstructure of AA 7075-T6 Aluminum Alloy Lap Joints at Optimal Predicted FSW Process Parameters
No full textThe lap joints of AA 7075-T6 aluminum alloy were assembled using the friction stir welding (FSW) technique. Experimental studies were performed to characterize the thermomechanical properties of these welds. The main goal of this research was to comprehensively assess the thermomechanical behavior of AA 7075-T6 aluminum alloy under FSW conditions. Tests were carried out at a tool rotational speed of 1320 rpm and at two advancing speeds of 70 mm/min and 120 mm/min, selected based on a previous study aiming to optimize the heat input during the FSW process. The experimental investigations involved the characterization of temperature profiles during welding, mechanical properties such as microhardness and tensile strength, and microstructure examination at the two advancing speed conditions. This study revealed that the welding speed has an obvious influence on the material thermal behavior during the FSW process. Indeed, the peak temperature obtained with a lower welding speed (70 mm/min) was higher by almost 10% compared to that obtained with a higher speed (120 mm/min). Moreover, by increasing the welding speed, the mechanical characteristics, such as microhardness and tensile strength, were increased by almost 5% for the mean microhardness and 6% for the ultimate tensile strength. Additionally, the microstructure examination demonstrated that, by decreasing the welding speed, more interaction between the tool and the material is observed, resulting in a deeper stir zone due to increased heat dissipation downwards into the material, affecting the thermal profile and influencing the resulting mechanical properties of the welded joint
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