508 research outputs found
Data fusion strategy for precise vehicle location for intelligent self-aware maintenance systems
Abstractâ Nowadays careful measurement applications are
handed over to Wired and Wireless Sensor Network. Taking
the scenario of train location as an example, this would lead to
an increase in uncertainty about position related to sensors
with long acquisition times like Balises, RFID and
Transponders along the track. We take into account the data
without any synchronization protocols, for increase the
accuracy and reduce the uncertainty after the data fusion
algorithms. The case studies, we have analysed, derived from
the needs of the project partners: train localization, head of an
auger in the drilling sector localization and the location of
containers of radioactive material waste in a reprocessing
nuclear plant. They have the necessity to plan the maintenance
operations of their infrastructure basing through architecture
that taking input from the sensors, which are localization and
diagnosis, maps and cost, to optimize the cost effectiveness and
reduce the time of operation
Precise vehicle location as a fundamental parameter for intelligent selfaware rail-track maintenance systems
The rail industry in the UK is undergoing substantial changes in response to a modernisation vision for 2040. Development and implementation of these will lead to a highly automated and safe railway. Real-time regulation of traffic will optimise the performance of the network, with trains running in succession within an adjacent movable safety zone. Critically, maintenance will use intelligent trainborne and track-based systems. These will provide accurate and timely information for condition based intervention at precise track locations, reducing possession downtime and minimising the presence of workers in operating railways. Clearly, precise knowledge of trainsâ real-time location is of paramount importance.
The positional accuracy demand of the future railway is less than 2m. A critical consideration of this requirement is the capability to resolve train occupancy in adjacent tracks, with the highest degree of confidence. A finer resolution is required for locating faults such as damage or missing parts, precisely.
Location of trains currently relies on track signalling technology. However, these systems mostly provide an indication of the presence of trains within discrete track sections. The standard Global Navigation Satellite Systems (GNSS), cannot precisely and reliably resolve location as required either.
Within the context of the needs of the future railway, state of the art location technologies and systems were reviewed and critiqued. It was found that no current technology is able to resolve location as required. Uncertainty is a significant factor. A new integrated approach employing complimentary technologies and more efficient data fusion process, can potentially offer a more accurate and robust solution. Data fusion architectures enabling intelligent self-aware rail-track maintenance systems are proposed
Relation of project managers' personality and project performance: an approach based on value stream mapping
Purpose: This work investigates the influence of project managersâ personality on the success of a project in a Multinational Corporation. The methodology proposed for analyzing the project managersâ personality is based on the Myers-Briggs Type Indicator.
Design/methodology/approach: Forty projects carried out in 2012 by multinational corporation, concerning new product development (NPD), have been analyzed, comparing the profile of project managers with results obtained in terms of traditional performance indexes (time delay and over-budget of projects) and performance indexes usually used in âLean Productionâ sector (waste time and type of âwastesâ). A detailed analysis of the most important âwastesâ during the project development is carried out using the Value Stream Mapping (VSM) technique.
Findings and Originality/value: Relying on the MyersâBriggs personality instrument, results show that extroverted managers (as opposed to introverted managers) carry out projects that show lower delay and lower waste time. Introverted managers often make âOver-processingâ and âDefectâ types of waste. Moreover, lower delay and over-budget have been shown by perceiving managers.
Research limitations: Regarding the limitations of this work it is necessary to highlight that we collected data from project managers in a retrospective way. While we believe that several aspects of our data collection effort helped enhance the accuracy of the results, future research could conduct real-time case study research to get more detailed insights into the proposed relationships and avoid retrospective bias. Moreover we focused on a single respondent, the project manager. This helped us ensure that their interpretations played an important role in product development. But, we cannot examined the opinion of team members that could be different from project managers opinion regarding some questions.
Originality/value: This research provides insight useful to develop proactive approaches to prevent project failures, including the creation of more effective messages and methods to help companies to make the best choices during managersÂŽ hiring. Moreover this research would allow organizations to better match the short-term organizational needs with appropriate personality types.Peer Reviewe
A design method for improving assembly and environmental sustainability in packaging solutions: a case study in household appliances
By using a functional requirement analysis, through Design for Manufacture and Assembly and Design for Environment principles, this paper aims at showing a new design method to improve the overall assembly features and environmental sustainability of a packaging solution. This method provides to rank functional requirements according to three different design specifications and also to the number of relationships they have with each other. At the same time, a ranked order of importance for the packaging parts has been realised, considering the number of performed functions. The purpose of this method is to support the designers in focusing their attention on the most important packaging parts and, at the same time, giving them a clear idea of which are the most important functional requirements to be satisfied. This study has been focused on domestic household packaging, but the provided method can be extended to any particular packaging solution and its findings are still valid. According to the Design for Environmental perspective, the actual and the new resulting packaging solutions have been then compared through Life Cycle Assessment method. The results have shown the new packaging solution being able to cut down the environmental impacts, on average, of approximately 30%
sustainability analysis of friction stir welding of aa5754 sheets
Abstract The environmental impact of friction stir welding process vs. welding parameters was evaluated and analysed in detail. To this purpose, butt joints in AA5754 aluminum alloy sheets were obtained at different rotational and welding speeds. All input and output data, in terms of materials, energies and emissions, were collected and analyzed using a life cycle assessment software in order to evaluate the environmental impact index. Sound weld was used as functional unit and all energy and material flows were based on it. The results given by the life cycle assessment analysis has shown that the environmental impact of friction stir welding is strongly affected by rotational and welding speeds. The environmental impact was also related to the mechanical properties of joints, expressed as ultimate tensile strength and ultimate elongation
autonomic cardiovascular control in hyperthyroid women during sleep
Hyperthyroidism is characterized by hyperadrenergic symptoms (i.e., tachycardia, anxiety, and increased metabolic state). Although hyperthyroid patients often complain about an impairment of sleep, no data are available on sleep characteristics and autonomic cardiovascular control during sleep in these patients. We aimed to assess sleep qualitative indices and autonomic cardiovascular regulation during sleep in hyperthyroidism (Hyperthyr) and after treatment. Six subjects with a first diagnosis of Graves' disease or hyperfunctioning nodule underwent a complete polysomnographic study (PSG) at the time of diagnosis and after the treatment, when they became euthyroid (Euthyr). ECG and respiratory signals were extracted and samples of consecutive 250â300 beats were analyzed using linear spectral and nonlinear entropy analysis of heart rate variability (HRV), during the different sleep stages. Heart rate was decreased and total power increased in Euthyr compared to Hyperthyr, both during wake and sleep; no changes of the sympathovagal balance were observed. Entropy analysis showed that regularity index was reduced in Euthyr compared to Hyperthyr, suggesting changes in the complexity of the cardiovascular control. Periodic leg movements (PLM) were reduced in Euthyr compared to Hyperthyr. In conclusion, hyperthyroidism seems to be associated with an increased sleep fragmentation, due to PLM and an altered cardiac autonomic control
Double-inlet single left ventricle: Echocardiographic anatomy with emphasis on the morphology of the atrioventricular valves and ventricular septal defect
AbstractThe echocardiographic anatomy of double inlet single left ventricle was studied in 57 patients, aged 1 day to 27 years (mean 6 years); the variables examined included morphology, size and function of the atrioventricular AV) valves and ventricular septal defect and their relation to pulmonary stenosis, aortic stenosis and aortic arch obstruction. The visceroatrial situs was solitus and the heart was in the left side of the chest in all 57 patients. A d-loop ventricle was present in 21 patients and an l-loop ventricle in 36. The great arteries were normally related (Holmes heart) in 8 patients and transposed in 49.In all hearts, the right AV valve was anterior to the left AV valve. In 53 patients, the tricuspid valve (right valve in d-loop and left valve in l-loop) was closer to and had attachments on the septum. The tricuspid valve straddled the outflow chamber in eight patients. No significant difference was noted in the mean AV valve diameter when comparing mitral and tricuspid valves within the same group or between the groups with a d- or l-loop ventricle. The right AV valve diameter had a significant direct correlation with the aortic valve diameter and the size or (he ventricular septal defect regardless of ventricular loop. Both AV valves were functionally normal in 34 patients. Among patients with AV valve dysfunction, the tricuspid valve tended to be stenotic in patients with an l-loop ventricle and regurgitant in patients with a d-loop ventricle. Mitral valve dysfunction was uncommon.The ventricular septal defect (46 patients) was separated from the semilunar valves in 24 patients (muscular defect) and adjacent to the anterior semilunar valve as a result of hypoplasia or malalignment, or both, of the infundibular septum (subaortic defect) in 19 patients. Multiple defects were present in three patients. The difect was unrestrictive in 26 patients, restrictive in 23 and could not be evaluated in 8. Pulmonary artery banding had been performed in 8 of the 26 patients with an unrestrictive defect and in 10 of the 23 patients with a restrictive defect. Only 4 of 19 subaortic defects compared with 16 of 24 muscular defects were restrictive. The size of the defect was significantly correlated with the measured pressure gradient. Among patients with transposition, only 2 of 13 with pulmonary stenosis had a restrictive ventricular septal defect compared with 15 of 30 without pulmonary stenosis. In patients with transposition, the defect size was significantly smaller when coarctation was present
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