959 resultados para Information by segment


Relevância:

80.00% 80.00%

Publicador:

Resumo:

This thesis adresses the problem of localization, and analyzes its crucial aspects, within the context of cooperative WSNs. The three main issues discussed in the following are: network synchronization, position estimate and tracking. Time synchronization is a fundamental requirement for every network. In this context, a new approach based on the estimation theory is proposed to evaluate the ultimate performance limit in network time synchronization. In particular the lower bound on the variance of the average synchronization error in a fully connected network is derived by taking into account the statistical characterization of the Message Delivering Time (MDT) . Sensor network localization algorithms estimate the locations of sensors with initially unknown location information by using knowledge of the absolute positions of a few sensors and inter-sensor measurements such as distance and bearing measurements. Concerning this issue, i.e. the position estimate problem, two main contributions are given. The first is a new Semidefinite Programming (SDP) framework to analyze and solve the problem of flip-ambiguity that afflicts range-based network localization algorithms with incomplete ranging information. The occurrence of flip-ambiguous nodes and errors due to flip ambiguity is studied, then with this information a new SDP formulation of the localization problem is built. Finally a flip-ambiguity-robust network localization algorithm is derived and its performance is studied by Monte-Carlo simulations. The second contribution in the field of position estimate is about multihop networks. A multihop network is a network with a low degree of connectivity, in which couples of given any nodes, in order to communicate, they have to rely on one or more intermediate nodes (hops). Two new distance-based source localization algorithms, highly robust to distance overestimates, typically present in multihop networks, are presented and studied. The last point of this thesis discuss a new low-complexity tracking algorithm, inspired by the Fano’s sequential decoding algorithm for the position tracking of a user in a WLAN-based indoor localization system.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

This book is dedicated to the Law and Economics analysis of civil liability of securities underwriters for the damage caused by material misstatements of corporate information by securities issuers. It seeks to answer a series of important questions. Who the are underwriters and what is their main role in the securities offering? Why there is a need for legal intervention in the underwriting market? What is so special about civil liability as an enforcement tool? How is civil liability used in a real world and does it really reach its goals? Finally, is there a need for a change and, if so, by what means?

Relevância:

80.00% 80.00%

Publicador:

Resumo:

In the last few years, a new generation of Business Intelligence (BI) tools called BI 2.0 has emerged to meet the new and ambitious requirements of business users. BI 2.0 not only introduces brand new topics, but in some cases it re-examines past challenges according to new perspectives depending on the market changes and needs. In this context, the term pervasive BI has gained increasing interest as an innovative and forward-looking perspective. This thesis investigates three different aspects of pervasive BI: personalization, timeliness, and integration. Personalization refers to the capacity of BI tools to customize the query result according to the user who takes advantage of it, facilitating the fruition of BI information by different type of users (e.g., front-line employees, suppliers, customers, or business partners). In this direction, the thesis proposes a model for On-Line Analytical Process (OLAP) query personalization to reduce the query result to the most relevant information for the specific user. Timeliness refers to the timely provision of business information for decision-making. In this direction, this thesis defines a new Data Warehuose (DW) methodology, Four-Wheel-Drive (4WD), that combines traditional development approaches with agile methods; the aim is to accelerate the project development and reduce the software costs, so as to decrease the number of DW project failures and favour the BI tool penetration even in small and medium companies. Integration refers to the ability of BI tools to allow users to access information anywhere it can be found, by using the device they prefer. To this end, this thesis proposes Business Intelligence Network (BIN), a peer-to-peer data warehousing architecture, where a user can formulate an OLAP query on its own system and retrieve relevant information from both its local system and the DWs of the net, preserving its autonomy and independency.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Acute type A aortic dissection is a serious emergency with a mortality rate of up to 40% within the first 24 h when left untreated. Surgical therapy needs to be initiated promptly. Due to this urgent situation, preoperative evaluation of the coronary arteries is not routinely performed in these patients. The aim of this study was to evaluate the accuracy of 64-slice computed tomography angiography (CTA) for postoperative coronary artery assessment in these patients. Ten consecutive patients with two or more cardiovascular risk factors were prospectively enrolled. Patients had type A aortic dissection treated surgically with a supracoronary graft of the ascending aorta. Performance of CTA to exclude significant stenosis (>50% lumen narrowing) and/or coronary artery dissection was compared with quantitative coronary angiography. A total of 147 segments were evaluated. Three segments (2%) were excluded from analysis. CTA correctly assessed one of three significant stenoses in three patients and correctly excluded coronary artery disease (CAD) in six of ten patients. One patient was rated false positive. Overall accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of CT for identifying coronary artery disease by segment was 98%, 33%, 99%, 50%, and 99%, respectively (P<0.05). By patient, it was 70%, 33%, 86%, 50%, and 75%, respectively. No coronary artery dissection was found. Noninvasive CTA may be a viable alternative to conventional angiography for postoperative coronary artery evaluation in patients with surgically treated type A aortic dissection and cardiovascular risk factors. An NPV of 99% should allow for reliable exclusion of CAD. Further studies with higher patient numbers are warranted.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Background The release of quality data from acute care hospitals to the general public is based on the aim to inform the public, to provide transparency and to foster quality-based competition among providers. Due to the expected mechanisms of action and possibly the adverse consequences of public quality comparison, it is a controversial topic. The perspective of physicians and nurses is of particular importance in this context. They are mainly responsible for the collection of quality-control data, and are directly confronted with the results of public comparison. The research focus of this qualitative study was to discover what the views and opinions of the Swiss physicians and nurses were regarding these issues. It was investigated as to how the two professional groups appraised the opportunities as well as the risks of the release of quality data in Switzerland. Methods A qualitative approach was chosen to answer the research question. For data collection, four focus groups were conducted with physicians and nurses who were employed in Swiss acute care hospitals. Qualitative content analysis was applied to the data. Results The results revealed that both occupational groups had a very critical and negative attitude regarding the recent developments. The perceived risks were dominating their view. In summary, their main concerns were: the reduction of complexity, the one-sided focus on measurable quality variables, risk selection, the threat of data manipulation and the abuse of published information by the media. An additional concern was that the impression is given that the complex construct of quality can be reduced to a few key figures, and it that it is constructed from a false message which then influences society and politics. This critical attitude is associated with the different value system and the professional self-concept that both physicians and nurses have, in comparison to the underlying principles of a market-based economy and the economic orientation of health care business. Conclusions The critical and negative attitude of Swiss physicians and nurses must, under all conditions, be heeded to and investigated regarding its impact on work motivation and identification with the profession. At the same time, the two professional groups are obligated to reflect upon their critical attitude and take a proactive role in the development of appropriate quality indicators for the publication of quality data in Switzerland.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Meta-cognition, or "thinking about thinking," has been studied extensively in humans, but very little is known about the process in animals. Although great apes and rhesus macaques (Macaca mulatta) have demonstrated multiple apparently meta-cognitive abilities, other species have either been largely ignored or failed to convincingly display meta-cognitive traits. Recent work by Marsh, however, raised the possibility that some species may possess rudimentary or partial forms of meta-cognition. This thesis sought to further investigate this possibility by running multiple comparative experiments. The goal of the first study was to examine whether lion-tailed macaques, a species that may have a rudimentary form of meta-cognition, are able to use an uncertainty response adaptively, and if so, whether they could use the response flexibly when the stimuli for which the subjects should be uncertain changed. The macaques' acquisition of the initial discrimination task is ongoing, and as such there were not yet data to support a conclusion either way. In the second study, tufted capuchins were required to locate a food reward hidden beneath inverted cups that sat on a Plexiglas tray. In some conditions the capuchins were shown where the food was hidden, in others they could infer its location, and in yet others they were not given information about the location of the food. On all trials, however, capuchins could optionally seek additional information by looking up through the Plexiglas into the cups. In general, capuchins did this less often when they were shown the food reward, but not when they could infer the reward's location. These data suggest capuchins only meta-cognitively control their information seeking in some conditions, and thus, add support to the potential for a rudimentary form of meta-cognition. In convergence with other studies, these results may represent early models for rudimentary meta-cognition, although viable alternative explanations still remain.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Myocardial perfusion imaging with SPECT (SPECT-MPI) and 64-slice CT angiography (CTA) are both established techniques for the noninvasive evaluation of coronary artery disease (CAD). Three-dimensional (3D) SPECT/CT image fusion may offer an incremental diagnostic value by integrating both sets of information. We report our first clinical experiences with fused 3D SPECT/CT in CAD patients. METHODS: Thirty-eight consecutive patients with at least 1 perfusion defect on SPECT-MPI (1-d adenosine stress/rest SPECT with (99m)Tc-tetrofosmin) and 64-slice CTA were included. 3D volume-rendered fused SPECT/CT images were generated and compared with the findings from the side-by-side analysis with regard to coronary lesion interpretation by assigning the perfusion defects to their corresponding coronary lesion. RESULTS: The fused SPECT/CT images added information on pathophysiologic lesion severity in 27 coronary stenoses (22%) of 12 patients (29%) (P<0.001). Among 40 equivocal lesions on side-by-side analysis, the fused interpretation confirmed hemodynamic significance in 14 lesions and excluded functional relevance in 10 lesions. In 3 lesions, assignment of perfusion defect and coronary lesion appeared to be reliable on side-by-side analysis but proved to be inaccurate on fused interpretation. Added diagnostic information by SPECT/CT was more commonly found in patients with stenoses of small vessels (P=0.004) and involvement of diagonal branches (P=0.01). CONCLUSION: In addition to being intuitively convincing, 3D SPECT/CT fusion images in CAD may provide added diagnostic information on the functional relevance of coronary artery lesions.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Currently photon Monte Carlo treatment planning (MCTP) for a patient stored in the patient database of a treatment planning system (TPS) can usually only be performed using a cumbersome multi-step procedure where many user interactions are needed. This means automation is needed for usage in clinical routine. In addition, because of the long computing time in MCTP, optimization of the MC calculations is essential. For these purposes a new graphical user interface (GUI)-based photon MC environment has been developed resulting in a very flexible framework. By this means appropriate MC transport methods are assigned to different geometric regions by still benefiting from the features included in the TPS. In order to provide a flexible MC environment, the MC particle transport has been divided into different parts: the source, beam modifiers and the patient. The source part includes the phase-space source, source models and full MC transport through the treatment head. The beam modifier part consists of one module for each beam modifier. To simulate the radiation transport through each individual beam modifier, one out of three full MC transport codes can be selected independently. Additionally, for each beam modifier a simple or an exact geometry can be chosen. Thereby, different complexity levels of radiation transport are applied during the simulation. For the patient dose calculation, two different MC codes are available. A special plug-in in Eclipse providing all necessary information by means of Dicom streams was used to start the developed MC GUI. The implementation of this framework separates the MC transport from the geometry and the modules pass the particles in memory; hence, no files are used as the interface. The implementation is realized for 6 and 15 MV beams of a Varian Clinac 2300 C/D. Several applications demonstrate the usefulness of the framework. Apart from applications dealing with the beam modifiers, two patient cases are shown. Thereby, comparisons are performed between MC calculated dose distributions and those calculated by a pencil beam or the AAA algorithm. Interfacing this flexible and efficient MC environment with Eclipse allows a widespread use for all kinds of investigations from timing and benchmarking studies to clinical patient studies. Additionally, it is possible to add modules keeping the system highly flexible and efficient.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Floral scents are important information cues used to organize foraging-related tasks in honeybees. The waggle dance, apart from encoding spatial information about food sources, might facilitate the transfer of olfactory information by increasing the dissipation of volatiles brought back by successful foragers. By assuming that food scents are more intensive on specific body parts of returning foragers, i.e., the posterior legs of pollen foragers and mouthparts of nectar foragers, we quantified the interactions between hive mates and foragers during dances advertising different types of food sources. For natural sources, a higher proportion of hive mates contacted the hind legs of pollen dancers (where the pollen loads were located) with their heads compared to non-pollen dancers. On the other hand, the proportion of head-to-head contacts was higher for non-pollen foragers during the waggle runs. When the food scent was manipulated, dancers collecting scented sugar solution had a higher proportion of head-to-head contacts and a lower proportion around their hind legs compared to dancers collecting unscented solution. The presence of food odors did not affect in-hive behaviors of dancers, but it increased the number of trophallaxes in-between waggle runs (i.e., during circle phases). These results suggest that the honeybee dance facilitates the olfactory information transfer between incoming foragers and hive mates, and we propose that excitatory displays in other social insect species serve the same purpose. While recent empirical and theoretical findings suggested that the colony level foraging benefits of the spatial information encoded in the waggle dance vary seasonally and with habitats, the role of the dance as a compound signal not only indicating the presence of a profitable resource but also amplifying the information transfer regarding floral odors may be important under any ecological circumstances.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

We present a technique for online compression of ECG signals using the Golomb-Rice encoding algorithm. This is facilitated by a novel time encoding asynchronous analog-to-digital converter targeted for low-power, implantable, long-term bio-medical sensing applications. In contrast to capturing the actual signal (voltage) values the asynchronous time encoder captures and encodes the time information at which predefined changes occur in the signal thereby minimizing the sensor's energy use and the number of bits we store to represent the information by not capturing unnecessary samples. The time encoder transforms the ECG signal data to pure time information that has a geometric distribution such that the Golomb-Rice encoding algorithm can be used to further compress the data. An overall online compression rate of about 6 times is achievable without the usual computations associated with most compression methods.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Ships’ protests have been used for centuries as legal documents to record and detail damages and indemnify Captains from fault. We use them in this article, along with data extracted through forensic synoptic analysis (McNally, 1994, 2004) to identify a tropical or subtropical system in the North Atlantic Ocean in 1785. They are shown to be viable sources of meteorological information. By comparing a damaging storm in New England in 1996, which included an offshore tropical system, with one reconstructed in 1785, we demonstrate that the tropical system identified in a ship’s protest played a significant role in the 1785 storm. With both forensic reconstruction and anecdotal evidence, we are able to assess that these storms are remarkably identical. The recurrence rate calculated in previous studies of the 1996 storm is 400–500 years. We suggest that reconstruction of additional years in the 1700s would provide the basis for a reanalysis of recurrence rates, with implications for future insurance and reinsurance rates. The application of the methodology to this new data source can also be used for extension of the hurricane database in the North Atlantic basin, and elsewhere, much further back into history than is currently available.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Conservation and monitoring of forest biodiversity requires reliable information about forest structure and composition at multiple spatial scales. However, detailed data about forest habitat characteristics across large areas are often incomplete due to difficulties associated with field sampling methods. To overcome this limitation we employed a nationally available light detection and ranging (LiDAR) remote sensing dataset to develop variables describing forest landscape structure across a large environmental gradient in Switzerland. Using a model species indicative of structurally rich mountain forests (hazel grouse Bonasa bonasia), we tested the potential of such variables to predict species occurrence and evaluated the additional benefit of LiDAR data when used in combination with traditional, sample plot-based field variables. We calibrated boosted regression trees (BRT) models for both variable sets separately and in combination, and compared the models’ accuracies. While both field-based and LiDAR models performed well, combining the two data sources improved the accuracy of the species’ habitat model. The variables retained from the two datasets held different types of information: field variables mostly quantified food resources and cover in the field and shrub layer, LiDAR variables characterized heterogeneity of vegetation structure which correlated with field variables describing the understory and ground vegetation. When combined with data on forest vegetation composition from field surveys, LiDAR provides valuable complementary information for encompassing species niches more comprehensively. Thus, LiDAR bridges the gap between precise, locally restricted field-data and coarse digital land cover information by reliably identifying habitat structure and quality across large areas.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Increasing commercial pressures on land are provoking fundamental and far-reaching changes in the relationships between people and land. Much knowledge on land-oriented investments projects currently comes from the media. Although this provides a good starting point, lack of transparency and rapidly changing contexts mean that this is often unreliable. The International Land Coalition, in partnership with Oxfam Novib, Centre de coopération internationale en recherche agronomique pour le développement (CIRAD), University of Pretoria, Centre for Development and Environment of the University of Bern (CDE), and GIZ, started to compile an inventory of land-related investments. This project aims to better understand the extent, trends and impacts of land-related investments by supporting an ongoing and systematic stocktaking exercise of the various investment projects currently taking place worldwide. It involves a large number of organizations and individuals working in areas where land transactions are being made, and able to provide details of such investments. The project monitors land transactions in rural areas that imply a transformation of land use rights from communities and smallholders to commercial use, and are made both by domestic and foreign investors (private actors, governments, government-back private investors). The focus is on investments for food or agrofuel production, timber extraction, carbon trading, mineral extraction, conservation and tourism. A novel way of using ITC to document land acquisitions in a spatially explicit way and by using an approach called “crowdsourcing” is being developed. This approach will allow actors to share information and knowledge directly and at any time on a public platform, where it will be scrutinized in terms of reliability and cross checked with other sources. Up to now, over 1200 deals have been recorded across 96 countries. Details of such transactions have been classified in a matrix and distributed to over 350 contacts worldwide for verification. The verified information has been geo-referenced and represented in two global maps. This is an open database enabling a continued monitoring exercise and the improvement of data accuracy. More information will be released over time. The opportunities arise from overcoming constraints by incomplete information by proposing a new way of collecting, enhancing and sharing information and knowledge in a more democratic and transparent manner. The intention is to develop interactive knowledge platform where any interested person can share and access information on land deals, their link to involved stakeholders, and their embedding into a geographical context. By making use of new ICT technologies that are more and more in the reach of local stakeholders, as well as open access and web-based spatial information systems, it will become possible to create a dynamic database containing spatial explicit data. Feeding in data by a large number of stakeholders, increasingly also by means of new mobile ITC technologies, will open up new opportunities to analyse, monitor and assess highly dynamic trends of land acquisition and rural transformation.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

BACKGROUND Newborn screening for CF started 01/2011 in Switzerland. We investigated the parents' opinions about the information received, their feelings, and overall approval of the screening. METHODS This is a prospective questionnaire survey of all parents of positively screened children. Parents were phoned by CF-centres and invited for diagnostic investigations. They completed a questionnaire after the visit to the CF-centre. RESULTS From 2011-2013, 246 families received the questionnaire and 138 (56%) replied. Of these 77 (60%) found the information received at birth satisfactory; 124 (91%) found the information provided in the CF-centre satisfactory. Most parents (n=98, 78%) felt troubled or anxious when the CF-centre called, 51 (38%) remained anxious after the visit. Most parents (n=122; 88%) were satisfied with the screening, 4 (3%) were not, and 12 (9%) were unsure. CONCLUSIONS The smooth organisation of the screening process, with personal information by a CF specialist and short delays between this information and the final diagnostic testing, might have contributed to reduce anxiety among parents. Most families were grateful that their child had been screened, and are happy with the process.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

El turismo rural ha sido incorporado por pequeños establecimientos agropecuarios del partido de Cnel. Suárez, provincia de Buenos Aires, Argentina, como actividad alternativa para mejorar la calidad de vida de sus miembros y superar situaciones de crisis agravadas por la marginalidad productiva del SO bonaerense, región a la que pertenecen. Bajo el programa Cambio Rural del INTA (Instituto Nacional de Tecnología Agropecuaria) conforman el Grupo 'Cortaderas II', junto a otros emprendedores interesados en valorar el medio rural. Han avanzado en el proceso de reconocimiento de su identidad y puesta en valor de recursos específicos con anclaje en el territorio. Esta identidad comienza a apreciarse internamente, a raíz de la dinámica grupal lograda y la incipiente articulación con otros actores para la construcción de un partenariado público y privado que genere sinergias y contribuya al desarrollo sustentable del territorio. Sin embargo, aún no es claramente percibida por el turista, cada vez más exigente. Por lo tanto, el presente trabajo persigue proponer indicadores para evaluar el desempeño de un Sistema de Gestión de Calidad con enfoque territorial que, adaptando el modelo europeo 'Marca de Calidad Territorial', sustente una estrategia comercial de diferenciación del servicio y simultáneamente, mida el progreso hacia una mejor calidad de vida y fortalecimiento de vínculos con la cultura local y el entorno físico-natural en el marco del desarrollo sustentable. La investigación se plantea para la micro escala, ya que se trata de un estudio de caso, relevándose información primaria mediante observación directa y entrevistas semi-estructuradas, complementada con información secundaria diagnóstica utilizada por INTA. Las características del grupo y su dinámica de funcionamiento bajo el programa Cambio Rural revelan que es posible adoptar un proceso de certificación participativa propuesto para cuatro pilares de la calidad: de Bienes y Servicios, Institucional, Social y Ambiental. El modelo se integra con indicadores de evaluación de desempeño, agrupados en áreas clave para cada una de las dimensiones de la sustentabilidad, que contemplan el paisaje y la gestión de los recursos naturales; el impacto económico de la actividad, la calidad de la oferta y satisfacción del turista; así como las relaciones sociales internas y los vínculos con otros actores del territorio. Principalmente se encontraron fortalezas en la búsqueda de partenariados y debilidades en aspectos de comunicación y promoción. Se considera que este sistema de herramientas de gestión sustentable permitiría superar las dificultades de una certificación individual, pudiendo aplicarse a emprendimientos con otra ubicación geográfica