Two parametric quasi-cyclic codes as hyperinvariants subspaces

It is known the relationship between cyclic codes and invariant subspaces. In this work we present a general- ization considering “generalized” cyclic codes and hy- perinvariant subspacesPostprint (published version

Cyclic codes as hyperinvariant subspaces

It is known the relationship between cyclic codes and invariant subspaces. We present in this work some codes which are obtained from invariant and hyperinvariant subspaces of the linear maps having associated matrices, in the standard basis, of a special form. xxxPostprint (published version

Asset integrity in the case of Wildfires at Wildland-Industrial Interfaces

Wildfires are uncontrolled fires involving the combustion of wild vegetation. When a wildfire front approaches the Wildland-Industrial Interface there can be a serious threat for process and storage equipment items located at the plant boundary. Ensuring the integrity of such equipment prevents the fire from spreading inside the plant site and causing major accidents such as fire, explosion, and toxic gas dispersion. The provision of adequate clearance areas is paramount since the early stages of the plant design. Once the facility is built, the implementation of safety measures can protect industrial items and ensure tank integrity. A tailored methodology for the calculation of safety distances between wild vegetation and tanks accounting for the safety system was developed and applied to a case study. The outcomes provide useful information on the effectiveness of safety measures for the protection of industrial items exposed to wildfire

CFD Simulation of Explosions in Fired Combustion Chambers

A wide range of equipment (boilers, furnaces, reformers, etc.) in industrial processes use fired combustion chambers to retrieve heat from a fuel. Although these systems have been used since long time and their safety has been significantly improved, explosions related with disturbances in the firing chamber still occur with certain frequency. The experimental testing of these explosions is challenging due to the complex design and large volume of combustion equipment, along with the presence of internal elements (heating tubes, burners, ignitors) and explosion relief panels. Moreover, empirical explosion evaluation methods may lack accuracy by not considering overpressure reflections and the effects of internal elements. Computational Fluid Dynamics (CFD) models are becoming nowadays accessible and runnable with ordinary desktop computers. In the present work, GEXCON FLACS software has been used to evaluate the effects of explosions inside combustion chambers. The results obtained confirm the potential utility of CFD simulations to analyze this type of explosions

Image similarity metrics suitable for infrared video stabilization during active wildfire monitoring : a comparative analysis

Aerial Thermal Infrared (TIR) imagery has demonstrated tremendous potential to monitor active forest fires and acquire detailed information about fire behavior. However, aerial video is usually unstable and requires inter-frame registration before further processing. Measurement of image misalignment is an essential operation for video stabilization. Misalignment can usually be estimated through image similarity, although image similarity metrics are also sensitive to other factors such as changes in the scene and lighting conditions. Therefore, this article presents a thorough analysis of image similarity measurement techniques useful for inter-frame registration in wildfire thermal video. Image similarity metrics most commonly and successfully employed in other fields were surveyed, adapted, benchmarked and compared. We investigated their response to different camera movement components as well as recording frequency and natural variations in fire, background and ambient conditions. The study was conducted in real video from six fire experimental scenarios, ranging from laboratory tests to large-scale controlled burns. Both Global and Local Sensitivity Analyses (GSA and LSA, respectively) were performed using state-of-the-art techniques. Based on the obtained results, two different similarity metrics are proposed to satisfy two different needs. A normalized version of Mutual Information is recommended as cost function during registration, whereas 2D correlation performed the best as quality control metric after registration. These results provide a sound basis for image alignment measurement and open the door to further developments in image registration, motion estimation and video stabilization for aerial monitoring of active wildland fires

COMPARTMENT AND FAÇADE LARGE SCALE TESTS: BEHAVIOR COMPARISON OF DIFFERENT INSULATING MATERIALS IN CASE OF FIRE

Fire safety community is currently concerned about the response of some widely used insulating materials in case of fire, due to the fact that existing regulations do not show how these materials behave in real conditions, which in some applications may be indeed critical. Within this context, several institutions have recently carried out large-scale tests with the aim of testing such insulator’s contribution to fire growth. In this paper we present a set of large scale tests of compartment and façade fires involving materials and configurations of different nature. Our experiments provided evidence that mineral wool insulator preserves its properties in case of fire, whilst other polymeric-type insulators contribute to fire growth in conditions close to the ones present in real fires

Thermal infrared video stabilization for aerial monitoring of active wildfires

Measuring wildland fire behavior is essential for fire science and fire management. Aerial thermal infrared (TIR) imaging provides outstanding opportunities to acquire such information remotely. Variables such as fire rate of spread (ROS), fire radiative power (FRP), and fireline intensity may be measured explicitly both in time and space, providing the necessary data to study the response of fire behavior to weather, vegetation, topography, and firefighting efforts. However, raw TIR imagery acquired by unmanned aerial vehicles (UAVs) requires stabilization and georeferencing before any other processing can be performed. Aerial video usually suffers from instabilities produced by sensor movement. This problem is especially acute near an active wildfire due to fire-generated turbulence. Furthermore, the nature of fire TIR video presents some specific challenges that hinder robust interframe registration. Therefore, this article presents a software-based video stabilization algorithm specifically designed for TIR imagery of forest fires. After a comparative analysis of existing image registration algorithms, the KAZE feature-matching method was selected and accompanied by pre- and postprocessing modules. These included foreground histogram equalization and a multireference framework designed to increase the algorithm's robustness in the presence of missing or faulty frames. The performance of the proposed algorithm was validated in a total of nine video sequences acquired during field fire experiments. The proposed algorithm yielded a registration accuracy between 10 and 1000x higher than other tested methods, returned 10x more meaningful feature matches, and proved robust in the presence of faulty video frames. The ability to automatically cancel camera movement for every frame in a video sequence solves a key limitation in data processing pipelines and opens the door to a number of systematic fire behavior experimental analyses. Moreover, a completely automated process supports the development of decision support tools that can operate in real time during an emergency

Differential clinical characteristics and prognosis of intraventricular conduction defects in patients with chronic heart failure

Intraventricular conduction defects (IVCDs) can impair prognosis of heart failure (HF), but their specific impact is not well established. This study aimed to analyse the clinical profile and outcomes of HF patients with LBBB, right bundle branch block (RBBB), left anterior fascicular block (LAFB), and no IVCDs. Clinical variables and outcomes after a median follow-up of 21 months were analysed in 1762 patients with chronic HF and LBBB (n = 532), RBBB (n = 134), LAFB (n = 154), and no IVCDs (n = 942). LBBB was associated with more marked LV dilation, depressed LVEF, and mitral valve regurgitation. Patients with RBBB presented overt signs of congestive HF and depressed right ventricular motion. The LAFB group presented intermediate clinical characteristics, and patients with no IVCDs were more often women with less enlarged left ventricles and less depressed LVEF. Death occurred in 332 patients (interannual mortality = 10.8%): cardiovascular in 257, extravascular in 61, and of unknown origin in 14 patients. Cardiac death occurred in 230 (pump failure in 171 and sudden death in 59). An adjusted Cox model showed higher risk of cardiac death and pump failure death in the LBBB and RBBB than in the LAFB and the no IVCD groups. LBBB and RBBB are associated with different clinical profiles and both are independent predictors of increased risk of cardiac death in patients with HF. A more favourable prognosis was observed in patients with LAFB and in those free of IVCDs. Further research in HF patients with RBBB is warranted

Computing the rate of spread of linear flame fronts by thermal image processing

et al.This work proposes a new thermal image processing method for computing the rate of spread (ROS) of forest fires. It is based on an application for linear flame fronts that are generated on flat surfaces with known dimensions. In the first step of the method, the correspondence between the points of the thermal image obtained and the real plane is calculated by means of a direct linear transformation (DLT). Subsequently, the position of the flame front is determined by applying a threshold-value-searching criterion within the temperature matrix of the target surface. The design principles for the implementation of this method in the laboratory are described in depth, as well as the considerations that must be taken into account if the method is to be correctly extrapolated to more complex experimental scenarios, such as prescribed burnings or real forest fire emergencies.This work was supported by the project 'Integration of robust perception, learning, and navigation systems in mobile robotics' (J-0929).This research is supported by the Spanish Ministry of Education and Science under projects DPI 2004-5414, TIC 2003-09291, and a Juan de la Cierva Post doctoral Fellow ship to JAC. It is also supported by the Department of Universities, Research and the Information Society (DURSI) of the Catalan government, the European Social Fund and the Polytechnic University of Catalonia (UPC).Peer Reviewe

Contribucio a l'estudi de la proteccio contra incendis en instal.lacions de proces

Centro de Informacion y Documentacion Cientifica (CINDOC). C/Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai