In-loop Feature Tracking for Structure and Motion with Out-of-core Optimization

In this paper, a novel and approach for obtaining 3D models from video sequences captured with hand-held cameras is addressed. We define a pipeline that robustly deals with different types of sequences and acquiring devices. Our system follows a divide and conquer approach: after a frame decimation that pre-conditions the input sequence, the video is split into short-length clips. This allows to parallelize the reconstruction step which translates into a reduction in the amount of computational resources required. The short length of the clips allows an intensive search for the best solution at each step of reconstruction which robustifies the system. The process of feature tracking is embedded within the reconstruction loop for each clip as opposed to other approaches. A final registration step, merges all the processed clips to the same coordinate frame

Potential to attract drivers out of their cars in dense urban areas.

Purpose Sustainable mobility urban policies intend reducing car use and increasing walking, cycling and public transport. However, this transfer from private car to these more sustainable modes is only a real alternative where distances are small and the public transport supply competitive enough. This paper proposes a methodology to calculate the number of trips that can be transferred from private car to other modes in city centres. Method The method starts analyzing which kind of trips cannot change its mode (purposes, conditions, safety , etc.), and then setting a process to determine under which conditions trips made by car between given O-D pairs can be transferable. Then, the application of demand models allow to determine which trips fulfil the transferability conditions. The process test the possibility of transfer in a sequential way: firs to walking, then cycling and finally to public transport. Results The methodology is tested through its application to the city of Madrid (Spain), with the result of only some 18% of the trips currently made by car could be made by other modes, under the same conditions of trip time, and without affecting their characteristics. Out of these trips, 75% could be made by public transport, 15% cycling and 10% on foot. The possible mode to be transferred depends on the location: city centre areas are more favourable for walking and cycling while city skirts could attract more PT trips. Conclusions The proposed method has demonstrated its validity to determine the potential of transferring trips out of cars to more sustainable modes. Al the same time it is clear that, even in areas with favourable conditions for walking, cycling and PT trips, the potential of transfer is limited because cars fulfil more properly special requirements of some trips and tours.

Magnetic Properties of Sputtered Permalloy/Molybdenum Multilayers

In this work, we report the magnetic properties of sputtered Permalloy (Py: Ni80Fe20)/molybdenum (Mo) multilayer thin films. We show that it is possible to maintain a low coercivity and a high permeability in thick sputtered Py films when reducing the out-of-plane component of the anisotropy by inserting thin film spacers of a non-magnetic material like Mo. For these kind of multilayers, we have found coercivities which are close to those for single layer films with no out-of-plane anisotropy. The coercivity is also dependent on the number of layers exhibiting a minimum value when each single Py layer has a thickness close to the transition thickness between Neel and Bloch domain walls.

OSIA: Out-of-order scheduling for in-order arriving in concurrent multi-path transfer.

One major problem of concurrent multi-path transfer (CMT) scheme in multi-homed mobile networks is that the utilization of different paths with diverse delays may cause packet reordering among packets of the same ?ow. In the case of TCP-like, the reordering exacerbates the problem by bringing more timeouts and unnecessary retransmissions, which eventually degrades the throughput of connections considerably. To address this issue, we ?rst propose an Out-of-order Scheduling for In-order Arriving (OSIA), which exploits the sending time discrepancy to preserve the in-order packet arrival. Then, we formulate the optimal traf?c scheduling as a constrained optimization problem and derive its closedform solution by our proposed progressive water-?lling solution. We also present an implementation to enforce the optimal scheduling scheme using cascaded leaky buckets with multiple faucets, which provides simple guidelines on maximizing the utilization of aggregate bandwidth while decreasing the probability of triggering 3 dupACKs. Compared with previous work, the proposed scheme has lower computation complexity and can also provide the possibility for dynamic network adaptability and ?ner-grain load balancing. Simulation results show that our scheme signi?cantly alleviates reordering and enhances transmission performance.

Riding out of the storm: How to deal with the complexity of grid and cloud management

Over the last decade, Grid computing paved the way for a new level of large scale distributed systems. This infrastructure made it possible to securely and reliably take advantage of widely separated computational resources that are part of several different organizations. Resources can be incorporated to the Grid, building a theoretical virtual supercomputer. In time, cloud computing emerged as a new type of large scale distributed system, inheriting and expanding the expertise and knowledge that have been obtained so far. Some of the main characteristics of Grids naturally evolved into clouds, others were modified and adapted and others were simply discarded or postponed. Regardless of these technical specifics, both Grids and clouds together can be considered as one of the most important advances in large scale distributed computing of the past ten years; however, this step in distributed computing has came along with a completely new level of complexity. Grid and cloud management mechanisms play a key role, and correct analysis and understanding of the system behavior are needed. Large scale distributed systems must be able to self-manage, incorporating autonomic features capable of controlling and optimizing all resources and services. Traditional distributed computing management mechanisms analyze each resource separately and adjust specific parameters of each one of them. When trying to adapt the same procedures to Grid and cloud computing, the vast complexity of these systems can make this task extremely complicated. But large scale distributed systems complexity could only be a matter of perspective. It could be possible to understand the Grid or cloud behavior as a single entity, instead of a set of resources. This abstraction could provide a different understanding of the system, describing large scale behavior and global events that probably would not be detected analyzing each resource separately. In this work we define a theoretical framework that combines both ideas, multiple resources and single entity, to develop large scale distributed systems management techniques aimed at system performance optimization, increased dependability and Quality of Service (QoS). The resulting synergy could be the key 350 J. Montes et al. to address the most important difficulties of Grid and cloud management.

Buckling instability of web plastifying dampers: analytical and numerical approach

This paper describes a numerical study on the instability of a brace-type seismic damper based on the out of plane yielding of the web of wide-flange steel sections (Web Plastifying Damper, WPD)The damper is intended to be installed in a framed structure as a standard diagonal brace. Under lateral forces, the damper is subjected to high axial forces, therefore its buckling instability is a matter of concern. Several finite element models representing WPDs with different axial stiffness and various geometries of their components were developed and analyzed taking into account both material and geometrical nonlinearities. The influence of several parameters defining the WPD in the load-displacement curve was examined. Furthermore, a simplified model to predict the buckling load is proposed.

Failure mechanism of reinforced concrete structural walls with and without confinement

This paper presents the results of cyclic loading tests on two large-scale reinforced concrete structural walls that were conducted at Purdue University. One of the walls had confinement reinforcement meeting ACI-318-11 requirements while the other wall did not have any confinement reinforcement. The walls were tested as part of a larger study aimed at indentifying parameters affecting failure modes observed to limit the drift capacity of structural walls in Chile during the Maule Earthquake of 2010. These failure modes include out-of-plane buckling (of the wall rather tan individual reinforcing bars), compression failure, and bond failure. This paper discusses the effects of confinement on failure mode. Distributions of unit strain and curvature obtained with a dense array of non-contact coordinate-tracking targets are also presented.

Analog mitigation of out of band strong interferers in wide band acquisition for multiband HF transmissions

It is clear that in the near future much broader transmissions in the HF band will replace part of the current narrow band links. Our personal view is that a real wide band signal is infeasible in this environment because the usage is typically very intensive and may suffer interferences from all over the world. Therefore, we envision that dynamic multiband transmissions may provide better satisfactory performance. From the very beginning, we observed that real links with our broadband transceiver suffered interferences out of our multiband but within the acquisition bandwidth that degrade the expected performance. Therefore, we concluded that a mitigation structure is required that operates on severely saturated signals as the interference may be of much higher power. In this paper we address a procedure based on Higher Order Crossings (HOC) statistics that are able to extract most of the signal structure in the case where the amplitude is severely distorted and allows the estimation of the interference carrier frequency to command a variable notch filter that mitigates its effect in the analog domain.

Spatial domain mitigation of out of band strong interferers in HF wide band acquisition using analog beamforming principles

We envision that dynamic multiband transmissions taking advantage of the receiver diversity (even for collocated antennas with different polarization or radiation pattern) will create a new paradigm for these links guaranteeing high quality and reliability. However, there are many challenges to face regarding the use of broadband reception where several out of band (with respect to multiband transmission) strong interferers, but still within the acquisition band, may limit dramatically the expected performance. In this paper we address this problem introducing a specific capability of the communication system that is able to mitigate these interferences using analog beamforming principles. Indeed, Higher Order Crossing (HOCs) joint statistics of the Single Input ? Multiple Output (SIMO) system are shown to effectively determine the angle on arrival of the wavefront even operating over highly distorted signals.

Development of One Meter Long Double-Sided CeO2 Buffered Ni-5at.W Templates by Reel-to-Reel Chemical Solution Deposition Route

High performance long-length coated conductors fabricated using various techniques have attracted a lot of interest recently. In this work, a reel-to-reel design for depositing double-sided coatings on long-length flexible metallic tapes via a chemical solution method is proposed and realized. The major achievement of the design is to combine the dip coating and drying processes in order to overcome the technical difficulties of dealing with the wet films on both sides of the tape. We report the successful application of the design to fabricate a one-meter-long double side coated CeO2/Ni-5at%W template. The CeO2 films on both sides exhibit a dense, crack-free morphology, and a high fraction of cube texture on the surface. Homogeneity studies on global texture over the length also reveal that the average full width at half maximum values of the in-plane and out-of-plane orientation on the CeO2 layer are 7.2 ° and 5.8° with standard deviation of 0.26° and 0.34°, respectively, being indicative of the high quality epitaxial growth of the films prepared in the continuous manner. An all chemical solution derived YBCOLow-TFA/Ce0.9La0.1O2 /Gd2Zr2O7/CeO2 structure is obtained on a short sample, demonstrating the possibility of producing long-length texture templates for coated conductors by this low cost deposition route.

X-ray microtomography analysis of the damage micromechanisms in 3D woven composites under low-velocity impact

3D woven composites reinforced with either S2 glass, carbon or a hybrid combination of both and containing either polyethylene or carbon z-yarns were tested under low-velocity impact. Different impact energies (in the range of 21–316 J) were used and the mechanical response (in terms of the impact strength and energy dissipated) was compared with that measured in high-performance, albeit standard, 2D laminates. It was found that the impact strength in both 2D and 3D materials was mainly dependent on the in-plane fiber fracture. Conversely, the energy absorption capability was primarily influenced by the presence of z-yarns, having the 3D composites dissipated over twice the energy than the 2D laminates, irrespective of their individual characteristics (fiber type, compaction degree, porosity, etc.). X-ray microtomography revealed that this improvement was due to the z-yarns, which delayed delamination and maintained the structural integrity of the laminate, promoting energy dissipation by tow splitting, intensive fiber breakage under the tup and formation of a plug by out-of-plane shear.

A numerical study of the influence of microvoids in the transverse mechanical response of unidirectional composites

The effect of porosity on the transverse mechanical properties of unidirectional fiber-reinforced composites is studied by means of computational micromechanics. The composite behavior is simulated by the finite element analysis of a representative volume element of the composite microstructure in which the random distribution of fibers and the voids are explicitly included. Two types of voids – interfiber voids and matrix voids – were included in the microstructure and the actual damage mechanisms in the composite, namely matrix and interface failure, were accounted for. It was found that porosity (in the range 1–5%) led to a large reduction in the transverse strength and the influence of both types of voids in the onset and propagation of damage throughout the microstructure was studied under transverse tension and compression. Finally, the failure locus of the composite lamina under transverse tension/compression and out-of-plane shear was obtained by means of computational micromechanics and compared with the predictions of Puck’s model and with experimental data available in the literature. The results show that the strength of composites is significantly reduced by the presence of voids

Health monitoring of web plastifying dampers subjected to cyclic loading through vibration tests

This article investigates experimentally the application of health monitoring techniques to assess the damage on a particular kind of hysteretic (metallic) damper called web plastifying dampers, which are subjected to cyclic loading. In general terms, hysteretic dampers are increasingly used as passive control systems in advanced earthquake-resistant structures. Nonparametric statistical processing of the signals obtained from simple vibration tests of the web plastifying damper is used here to propose an area index damage. This area index damage is compared with an alternative energy-based index of damage proposed in past research that is based on the decomposition of the load?displacement curve experienced by the damper. Index of damage has been proven to accurately predict the level of damage and the proximity to failure of web plastifying damper, but obtaining the load?displacement curve for its direct calculation requires the use of costly instrumentation. For this reason, the aim of this study is to estimate index of damage indirectly from simple vibration tests, calling for much simpler and cheaper instrumentation, through an auxiliary index called area index damage. Web plastifying damper is a particular type of hysteretic damper that uses the out-of-plane plastic deformation of the web of I-section steel segments as a source of energy dissipation. Four I-section steel segments with similar geometry were subjected to the same pattern of cyclic loading, and the damage was evaluated with the index of damage and area index damage indexes at several stages of the loading process. A good correlation was found between area index damage and index of damage. Based on this correlation, simple formulae are proposed to estimate index of damage from the area index damage.

Thinking way out of the box

l objeto de este trabajo es investigar sobre la arquitectura futurista mediante la figura de Jan Kaplický, el cual realizó planteamientos y arquitecturas que todavía hoy son realmente innovadoras e impactantes, centrando el tema en sus propuestas de vanguardia sobre lo doméstico. La obra elegida para este análisis es la House for a Helicopter Pilot (1979), una arquitectura nómada y cinética en que se habitaría una cápsula modular que puede elevar o bajar sus brazos hidráulicos y luego, una vez cansado el usuario del entorno, podría abandonarlo y encontrar otro lugar salvaje en que situarse. Al ser una obra no construida y utópica, sobre la que no hay apenas documentación, se propone como objetivo indagar sobre esta arquitectura alternativa que hoy en día sigue resultando innovadora, y realizar hipótesis explorando los detalles y objetos que aparecen en la escasa documentación existente, profundizando en las ideas utópicas de Jan Kaplicky

Post-CMOS compatible high-throughput fabrication of AIN-based piezoelectric microcantilevers

A post-complementary metal oxide semiconductor (CMOS) compatible microfabrication process of piezoelectric cantilevers has been developed. The fabrication process is suitable for standard silicon technology and provides low-cost and high-throughput manufacturing. This work reports design, fabrication and characterization of piezoelectric cantilevers based on aluminum nitride (AlN) thin films synthesized at room temperature. The proposed microcantilever system is a sandwich structure composed of chromium (Cr) electrodes and a sputtered AlN film. The key issue for cantilever fabrication is the growth at room temperature of the AlN layer by reactive sputtering, making possible the innovative compatibility of piezoelectric MEMS devices with CMOS circuits already processed. AlN and Cr have been etched by inductively coupled plasma (ICP) dry etching using a BCl3–Cl2–Ar plasma chemistry. As part of the novelty of the post-CMOS micromachining process presented here, a silicon Si (1 0 0) wafer has been used as substrate as well as the sacrificial layer used to release the microcantilevers. In order to achieve this, the Si surface underneath the structure has been wet etched using an HNA (hydrofluoric acid + nitric acid + acetic acid) based solution. X-ray diffraction (XRD) characterization indicated the high crystalline quality of the AlN film. An atomic force microscope (AFM) has been used to determine the Cr electrode surface roughness. The morphology of the fabricated devices has been studied by scanning electron microscope (SEM). The cantilevers have been piezoelectrically actuated and their out-of-plane vibration modes were detected by vibrometry.