947 resultados para Unreliable Equipment
Resumo:
OBJECTIVE To compare the physical activity levels of overweight and non overweight 3- to 5-y-old children while attending preschool. A secondary aim was to evaluate weight-related differences in hypothesized parental determinants of child physical activity behavior. DESIGN Cross-sectional study. SUBJECTS A total of 245, 3- to 5-y-olds (127 girls, 118 boys) and their parent(s) (242 mothers, 173 fathers) recruited from nine preschools. Overweight status determined using the age- and sex-specific 85th percentile for body mass index (BMI) from CDC Growth Charts. MEASUREMENTS Physical activity during the preschool day was assessed on multiple days via two independent objective measures direct observation using the observation system for recording activity in preschools (OSRAP) and real-time accelerometry using the MTI/CSA 7164 accelerometer. Parents completed a take-home survey assessing sociodemographic information, parental height and weight, modeling of physical activity, support for physical activity, active toys and sporting equipment at home, child’s television watching, frequency of park visitation, and perceptions of child competence. RESULTS Overweight boys were significantly less active than their nonoverweight peers during the preschool day. No significant differences were observed in girls. Despite a strong association between childhood overweight status and parental obesity, no significant differences were observed for the hypothesized parental influences on physical activity behavior. CONCLUSIONS Our results suggest that a significant proportion of overweight children may be at increased risk for further gains in adiposity because of low levels of physical activity during the preschool day.
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OBJECTIVE To compare the physical activity levels of overweight and non overweight 3- to 5-y-old children while attending preschool. A secondary aim was to evaluate weight-related differences in hypothesized parental determinants of child physical activity behavior. DESIGN: Cross-sectional study. SUBJECTS A total of 245, 3- to 5-y-olds (127 girls, 118 boys) and their parent(s) (242 mothers, 173 fathers) recruited from nine preschools. Overweight status determined using the age- and sex-specific 85th percentile for body mass index (BMI) from CDC Growth Charts. MEASUREMENTS Physical activity during the preschool day was assessed on multiple days via two independent objective measuresFdirect observation using the observation system for recording activity in preschools (OSRAP) and real-time accelerometry using the MTI/CSA 7164 accelerometer. Parents completed a take-home survey assessing sociodemographic information, parental height and weight, modeling of physical activity, support for physical activity, active toys and sporting equipment at home, child’s television watching, frequency of park visitation, and perceptions of child competence. RESULTS Overweight boys were significantly less active than their nonoverweight peers during the preschool day. No significant differences were observed in girls. Despite a strong association between childhood overweight status and parental obesity, no significant differences were observed for the hypothesized parental influences on physical activity behavior. CONCLUSIONS Our results suggest that a significant proportion of overweight children may be at increased risk for further gains in adiposity because of low levels of physical activity during the preschool day.
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The Wet Tropics region has a unique water asset and is also considered a priority region for the improvement of water quality entering the Great Barrier Reef due to a combination of high rainfall, intensive agricultural use, urban areas and the proximity of valuable reef assets to the coast. Agricultural activities are one of many identified threats to water quality and water flows in the Wet Tropics in terms of sediment and pollutant-related water quality decline. Information describing the current state of agricultural management practices across the region is patchy at best. Based on the best available information on agricultural management practices in the Wet Tropics in 2008, it is clear that opportunities exist to improve nutrient, sediment and pesticide management practice to reduce the impact on the water asset and the Great Barrier Reef. Based on current understandings of practices and the relationship between practices and reef water quality, the greatest opportunities for improved water quality are as follows: · nutrients – correct rate and the placement of fertilisers; · pesticides – improve weed control planning, herbicide rates and calibration practice; and · soil and sediment – implement new farming system practices. The 2008-09 Reef Rescue program sought to accelerate the rate of adoption of improved management practices and through Terrain invested $6.8M in the 2008-09 year for: · landholder water quality improvement incentive payments; · cross regional catchment repair of wetlands and riparian lands in areas of high sediment or nutrient loss; and · partnerships in the region to lever resources and support for on-ground practice change. The program delivered $3,021,999 in onground incentives to landholders in the Wet Tropics to improve farm practices from D or C level to B or A level. The landholder Water Quality Incentives Grants program received 300 individual applications for funding and funded 143 individual landholders to implement practice change across 36,098 ha of farm land. It is estimated that the Reef Rescue program facilitated practice change across 21% of the cane industry, and 20% of the banana industry. The program levered an additional $2,441,166 in landholder cash contributions and a further $907,653 in non-cash in-kind contributions bringing the total project value of the landholder grants program in the Wet Tropics to $6,370,819. Most funded projects targeted multiple water quality objectives with a focus on nutrient and sediment reduction. Of the 143 projects funded, 115 projects addressed nutrient management either as the primary focus or in combination with strategies that targeted other water quality objectives. Overall, 82 projects addressed two or more water quality targets. Forty-five percent of incentive funds were allocated to new farming system practices (direct drill legumes, zonal tillage equipment, permanent beds, min till planting equipment, GPS units, laser levelling), followed by 24% allocated to subsurface fertiliser applicators (subsurface application of fertiliser using a stool splitter or beside the stool, at the correct Six Easy Steps rate). As a result, Terrain estimates that the incentive grants achieved considerable reductions in nitrogen, phosphorus, sediment and pesticide loads. The program supported nutrient management training of 167 growers managing farms covering over 20% of the area harvested in 2008, and 18 industry advisors and resellers. This resulted in 115 growers (155 farms) developing nutrient management plans. The program also supported Integrated Weed Management training of 80 growers managing farms covering 8% of the area harvested in 2008, and 6 industry advisors and resellers. This report, which draws on the best available Reef Rescue Management Monitoring, Evaluation, Reporting, and Improvement (MERI) information to evaluate program performance and impact on water quality outcomes, is the first in a series of annual reports that will assess and evaluate the impact of the Reef Rescue program on agricultural practices and water quality outcomes. The assessment is predominantly focused on the cane industry because of data availability. In the next stage, efforts will expand to: · improve practice data for the banana and grazing industry; · gain a better understanding of the water quality trends and the factors influencing them in the Wet Tropics; in particular work will focus on linking the results of the Paddock to Reef monitoring program and practice change data to assess program impact; · enhance estimations of the impact of practice change on pollutant loads from agricultural land use; · gain a better understanding of the extent of ancillary practice (change not directly funded) resulting from Reef Rescue training/ education/communication programs; and · provide a better understanding of the economic cost of practice change across the Wet Tropics region. From an ecological perspective, water quality trends and the factors that may be contributing to change, require further investigation. There is a critical need to work towards an enhanced understanding of the link between catchment land management practice change and reef water quality, so that reduced nutrient, sediment, and pesticide discharge to the Great Barrier Reef can be quantified. This will also assist with future prioritisation of grants money to agricultural industries, catchments and sub catchments. From a social perspective, the program has delivered significant water quality benefits from landholder education and training. It is believed that these activities are giving landholders the information and tools to implement further lasting change in their production systems and in doing so, creating a change in attitude that is supportive and inclusive of Natural Resource Management (NRM). The program in the Wet Tropics has also considerably strengthened institutional partnerships for NRM, particularly between NRM and industry and extension organisations. As a result of the Reef Rescue program, all institutions are actively working together to collectively improve water quality. The Reef Rescue program is improving water quality entering the Great Barrier Reef Lagoon by catalysing substantial activity in the Wet Tropics region to improve land management practices and reduce the water quality impact of agricultural landscapes. The solid institutional partnerships between the regional body, industry, catchment and government organisations have been fundamental to the successful delivery of the landholder grant and catchment rehabilitation programs. Landholders have generally had a positive perception and reaction to the program, its intent, and the practical, focused nature of grant-based support. Demand in the program was extremely high in 2008-09 and is expected to increase in 2009-2010.
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Level crossing risk continues to be a significant safety concern for the security of rail operations around the world. Over the last decade or so, a third of railway related fatalities occurred as a direct result of collisions between road and rail vehicles in Australia. Importantly, nearly half of these collisions occurred at railway level crossings with no active protection, such as flashing lights or boom barriers. Current practice is to upgrade level crossings that have no active protection. However, the total number of level crossings found across Australia exceed 23,500, and targeting the proportion of these that are considered high risk (e.g. public crossings with passive controls) would cost in excess of AU$3.25 billion based on equipment, installation and commissioning costs of warning devices that are currently type approved. Level crossing warning devices that are low-cost provide a potentially effective control for reducing risk; however, over the last decade, there have been significant barriers and legal issues in both Australia and the US that have foreshadowed their adoption. These devices are designed to have significantly lower lifecycle costs compared with traditional warning devices. They often make use of use of alternative technologies for train detection, wireless connectivity and solar energy supply. This paper describes the barriers that have been encountered for the adoption of these devices in Australia, including the challenges associated with: (1) determining requisite safety levels for such devices; (2) legal issues relating to duty of care obligations of railway operators; and (3) issues of Tort liability around the use of less than fail-safe equipment. This paper provides an overview of a comprehensive safety justification that was developed as part of a project funded by a collaborative rail research initiative established by the Australian government, and describes the conceptual framework and processes being used to justify its adoption. The paper provides a summary of key points from peer review and discusses prospective barriers that may need to be overcome for future adoption. A successful outcome from this process would result in the development of a guideline for decision-making, providing a precedence for adopting low-cost level crossing warning devices in other parts of the world. The framework described in this paper also provides relevance to the review and adoption of analogous technologies in rail and other safety critical industries.
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Intelligent Transport System (ITS) technology is seen as a cost-effective way to increase the conspicuity of approaching trains and the effectiveness of train warnings at level crossings by providing an in-vehicle warning of an approaching train. The technology is often seen as a potential low-cost alternative to upgrading passive level crossings with traditional active warning systems (flashing lights and boom barriers). ITS platforms provide sensor, localization and dedicated short-range communication (DSRC) technologies to support cooperative applications such as collision avoidance for road vehicles. In recent years, in-vehicle warning systems based on ITS technology have been trialed at numerous locations around Australia, at level crossing sites with active and passive controls. While significant research has been conducted on the benefits of the technology in nominal operating modes, little research has focused on the effects of the failure modes, the human factors implications of unreliable warnings and the technology adoption process from the railway industry’s perspective. Many ITS technology suppliers originate from the road industry and often have limited awareness of the safety assurance requirements, operational requirements and legal obligations of railway operators. This paper aims to raise awareness of these issues and start a discussion on how such technology could be adopted. This paper will describe several ITS implementation cenarios and discuss failure modes, human factors considerations and the impact these scenarios are likely to have in terms of safety, railway safety assurance requirements and the practicability of meeting these requirements. The paper will identify the key obstacles impeding the adoption of ITS systems for the different implementation scenarios and a possible path forward towards the adoption of ITS technology.
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We first classify the state-of-the-art stream authentication problem in the multicast environment and group them into Signing and MAC approaches. A new approach for authenticating digital streams using Threshold Techniques is introduced. The new approach main advantages are in tolerating packet loss, up to a threshold number, and having a minimum space overhead. It is most suitable for multicast applications running over lossy, unreliable communication channels while, in same time, are pertain the security requirements. We use linear equations based on Lagrange polynomial interpolation and Combinatorial Design methods.
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This article presents the field applications and validations for the controlled Monte Carlo data generation scheme. This scheme was previously derived to assist the Mahalanobis squared distance–based damage identification method to cope with data-shortage problems which often cause inadequate data multinormality and unreliable identification outcome. To do so, real-vibration datasets from two actual civil engineering structures with such data (and identification) problems are selected as the test objects which are then shown to be in need of enhancement to consolidate their conditions. By utilizing the robust probability measures of the data condition indices in controlled Monte Carlo data generation and statistical sensitivity analysis of the Mahalanobis squared distance computational system, well-conditioned synthetic data generated by an optimal controlled Monte Carlo data generation configurations can be unbiasedly evaluated against those generated by other set-ups and against the original data. The analysis results reconfirm that controlled Monte Carlo data generation is able to overcome the shortage of observations, improve the data multinormality and enhance the reliability of the Mahalanobis squared distance–based damage identification method particularly with respect to false-positive errors. The results also highlight the dynamic structure of controlled Monte Carlo data generation that makes this scheme well adaptive to any type of input data with any (original) distributional condition.
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An in situ X-ray diffraction investigation of goethite-seeded Al(OH)3 precipitation from synthetic Bayer liquor at 343 K has been performed. The presence of iron oxides and oxyhydroxides in the Bayer process has implications for alumina reversion, which causes significant process losses through unwanted gibbsite precipitation, and is also relevant for the nucleation and growth of scale on mild steel process equipment. The gibbsite, bayerite and nordstrandite polymorphs of Al(OH)3 precipitated from the liquor; gibbsite appeared to precipitate first, with subsequent formation of bayerite and nordstrandite. A Rietveld-based approach to quantitative phase analysis was implemented for the determination of absolute phase abundances as a function of time, from which kinetic information for the formation of the Al(OH)3 phases was determined.
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Background Person-to-person transmission of respiratory pathogens, including Pseudomonas aeruginosa, is a challenge facing many cystic fibrosis (CF) centres. Viable P aeruginosa are contained in aerosols produced during coughing, raising the possibility of airborne transmission. Methods Using purpose-built equipment, we measured viable P aeruginosa in cough aerosols at 1, 2 and 4 m from the subject (distance) and after allowing aerosols to age for 5, 15 and 45 min in a slowly rotating drum to minimise gravitational settling and inertial impaction (duration). Aerosol particles were captured and sized employing an Anderson Impactor and cultured using conventional microbiology. Sputum was also cultured and lung function and respiratory muscle strength measured. Results Nineteen patients with CF, mean age 25.8 (SD 9.2) years, chronically infected with P aeruginosa, and 10 healthy controls, 26.5 (8.7) years, participated. Viable P aeruginosa were detected in cough aerosols from all patients with CF, but not from controls; travelling 4 m in 17/18 (94%) and persisting for 45 min in 14/18 (78%) of the CF group. Marked inter-subject heterogeneity of P aeruginosa aerosol colony counts was seen and correlated strongly (r=0.73–0.90) with sputum bacterial loads. Modelling decay of viable P aeruginosa in a clinic room suggested that at the recommended ventilation rate of two air changes per hour almost 50 min were required for 90% to be removed after an infected patient left the room. Conclusions Viable P aeruginosa in cough aerosols travel further and last longer than recognised previously, providing additional evidence of airborne transmission between patients with CF.
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The world of Construction is changing, so too are the expectations of stakeholders regarding strategies for adapting existing resources (people, equipment and finances), processes and tools to the evolving needs of the industry. Building Information Modelling (BIM) is a data-rich, digital approach for representing building information required for design and construction. BIM tools play a crucial role and are instrumental to current approaches, by industry stakeholders, aimed at harnessing the power of a single information repository for improved project delivery and maintenance. Yet, building specifications - which document information on material quality, and workmanship requirements - remain distinctly separate from model information typically represented in BIM models. BIM adoption for building design, construction and maintenance is an industry-wide strategy aimed at addressing such concerns about information fragmentation. However, to effectively reduce inefficiencies due to fragmentation, BIM models require crucial building information contained in specifications. This paper profiles some specification tools which have been used in industry as a means of bridging the BIM-Specifications divide. We analyse the distinction between current attempts at integrating BIM and specifications and our approach which utilizes rich specification information embedded within objects in a product library as a method for improving the quality of information contained in BIM objects at various levels of model development.
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The preventive maintenance of traction equipment for Very High Speed Trains (VHST) nowadays is becoming very expensive owing to the high complexity and quality of these components that require high reliability. An efficient maintenance approach like the Condition-Based Maintenance (CBM) should be implemented to reduce the costs. For this purpose, an experimental full-scale test rig for the CBM of VHST traction equipment has been designed to investigate in detail failures in the main mechanical components of system, i.e. motor, bearings and gearbox. The paper describes the main characteristics of this unique test rig, able to reproduce accurately the train operating conditions, including the relative movements of the motor, the gearbox and the wheel axle. Gearbox, bearing seats and motor are equipped by accelerometers, thermocouples, torque meter and other sensors in different positions. The testing results give important information about the most suitable sensor position and type to be installed for each component and show the effectiveness of the techniques used for the signal analysis in order to identify faults of the gearbox and motor bearings.
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Vehicular Ad-hoc Networks (VANETs) can make roads safer, cleaner, and smarter. It can offer a wide range of services, which can be safety and non-safety related. Many safety-related VANETs applications are real-time and mission critical, which would require strict guarantee of security and reliability. Even non-safety related multimedia applications, which will play an important role in the future, will require security support. Lack of such security and privacy in VANETs is one of the key hindrances to the wide spread implementations of it. An insecure and unreliable VANET can be more dangerous than the system without VANET support. So it is essential to make sure that “life-critical safety” information is secure enough to rely on. Securing the VANETs along with appropriate protection of the privacy drivers or vehicle owners is a very challenging task. In this work we summarize the attacks, corresponding security requirements and challenges in VANETs. We also present the most popular generic security policies which are based on prevention as well detection methods. Many VANETs applications require system-wide security support rather than individual layer from the VANETs’ protocol stack. In this work we will review the existing works in the perspective of holistic approach of security. Finally, we will provide some possible future directions to achieve system-wide security as well as privacy-friendly security in VANETs.
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Wireless Sensor Networks (WSNs) are employed in numerous applications in different areas including military, ecology, and health; for example, to control of important information like the personnel position in a building, as a result, WSNs need security. However, several restrictions such as low capability of computation, small memory, limited resources of energy, and the unreliable channels employ communication in using WSNs can cause difficulty in use of security and protection in WSNs. It is very essential to save WSNs from malevolent attacks in unfriendly situations. Such networks require security plan due to various limitations of resources and the prominent characteristics of a wireless sensor network which is a considerable challenge. This article is an extensive review about problems of WSNs security, which examined recently by researchers and a better understanding of future directions for WSN security.
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This research adopts three different theoretical lenses- the attention-based view, institutional perspective and network theory- to investigate the effect of externally oriented capabilities (absorptive capacity and networking capabilities) on corporate entrepreneurship. Based on an Australian and Iranian sample of mining equipment, technology and service providers, this thesis provides new understanding of why some firms are able to generate higher levels of corporate entrepreneurship than others and opens new directions for more capabilities-oriented research in corporate entrepreneurship. In particular, this research provides new insight into how entrepreneurial management, institutional context and external knowledge search breadth shape the relationship between externally oriented capabilities and corporate entrepreneurship.
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This chapter focuses on the physicality of the iPad as an object, and how that physicality affects the interactions children have with the device generally, and the apps specifically. Thinking about the physicality of the iPad is important because the materials, size, weight and appearance make the iPad quite unlike most other toys and equipment in the kindergarten space. Most strikingly, this physicality does not ‘represent’ the virtual vast dimensions of the iPad brought about through the diverse functions and contents of the apps contained in it. While the iPad is small enough and functional enough to be easily handled and operated even by young children, it is capable of performing highly complex, highly technological tasks that take it beyond its diminutive dimensions. This virtual-actual contrast is interesting to consider in relation to the other resources more commonly found in a kindergarten space. While objects such as toys, bricks, building materials often do prompt the child to imagine and invent beyond the physical boundaries of the toy, they not have the same types of virtual-actual contrasts of a digital device such as the iPad. How then, might children be drawn to the iPad because of its physical, technological and virtual difference? Particularly, how might this virtual-actual difference impact on the physical skills associated with writing and drawing: skills usually learnt through the use of a pencil and paper? While the research project did not set out to compare how digital and paper-based resources affect writing and drawing skills there was great interest to see how young children negotiated drawing and writing on the shiny glass surface of the iPad.