964 resultados para construction applications


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Integrity of Real Time Kinematic (RTK) positioning solutions relates to the confidential level that can be placed in the information provided by the RTK system. It includes the ability of the RTK system to provide timely valid warnings to users when the system must not be used for the intended operation. For instance, in the controlled traffic farming (CTF) system that controls traffic separates wheel beds and root beds, RTK positioning error causes overlap and increases the amount of soil compaction. The RTK system’s integrity capacity can inform users when the actual positional errors of the RTK solutions have exceeded Horizontal Protection Levels (HPL) within a certain Time-To-Alert (TTA) at a given Integrity Risk (IR). The later is defined as the probability that the system claims its normal operational status while actually being in an abnormal status, e.g., the ambiguities being incorrectly fixed and positional errors having exceeded the HPL. The paper studies the required positioning performance (RPP) of GPS positioning system for PA applications such as a CTF system, according to literature review and survey conducted among a number of farming companies. The HPL and IR are derived from these RPP parameters. A RTK-specific rover autonomous integrity monitoring (RAIM) algorithm is developed to determine the system integrity according to real time outputs, such as residual square sum (RSS), HDOP values. A two-station baseline data set is analyzed to demonstrate the concept of RTK integrity and assess the RTK solution continuity, missed detection probability and false alarm probability.

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Employing multilevel inverters is a proper solution to reduce harmonic content of output voltage and electromagnetic interference in high power electronic applications. In this paper, a new pulse width modulation method for multilevel inverters is proposed in which power devices’ on-off switching times have been considered. This method can be surveyed in order to analyse the effect of switching time on harmonic contents of output voltage in high frequency applications when a switching time is not negligible compared to a switching cycle. Fast Fourier transform calculation and analysis of output voltage waveforms and harmonic contents with regard to switching time variation are presented in this paper for a single phase (3, 5)-level inverters used in high voltage and high frequency converters. Mathematical analysis and MATLAB simulation results have been carried out to validate the proposed method.

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This paper reports on an intervention study planned to help Year 6 students construct the multiplicative structure underlying decimal-number numeration. Three types of intervention were designed from a numeration model developed from a large study of 173 Year 6 students’ decimal-number knowledge. The study found that students could acquire multiplicative structure as an abstract schema if instruction took account of prior knowledge as informed by the model.

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Since the early 1980s, researchers and practitioners in the organisational and management fields have presumed a link between organisational, or corporate, culture and organisational performance. Whilst many believe this exists, other authors have been critical of the validity of such studies. Part of this doubt stems from a reliance on measures of organisational performance that are based purely on financial measures of business growth. Using the construction industry as the subject of his research, Vaughan Coffey traces the development of the literature on organisational culture and business effectiveness and investigates the culture–performance link using a new and highly objective measure of company performance and an evaluation of organisational culture, which is largely behaviourally-based. Providing a theoretical contribution to the field, this work shows that various cultural traits appear to be closely linked to objectively measured organisational effectiveness. This book will be valuable to professionals and researchers in the fields of management and public policy. It indicates directions for construction companies to develop and change, and in doing so strengthen their chances of remaining strong when opportunities for work might deplete and only the most successful companies will be able to survive.---- Selected Contents: 1. An Introduction to Organizations, Culture, Performance and Construction 2. Organizations, Culture and Climate 3. Organizational Culture Studies 4. Measuring Organizational Performance and Effectiveness 5. Organizational Culture and Effectiveness – The Link Between Them 6. Research on the Relationship between Organizational Culture and Performance in Hong Kong Construction Companies 7. The Hong Kong Experiment – Presentation of Demographic Data, Overall Results and some Descriptive and Qualitative Analysis 8. Detailed Statistical Analysis of the Docs and Pass Data in Relation to the Major Research Questions 9. Four Hong Kong Construction Mini-Case Studies 10. Conclusions and Future Research Directions

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This paper has two main sections, the first of which presents a summarized review of the literature concerning previous studies on the implementation of ISO 9000 quality management systems (QMSs) both in global construction companies as well as in Indonesian construction firms, and the perceived correlation between organisational culture and QMS practices in the construction sector. The first section of the paper contributes to the development of the second section, which presents details of the research project being undertaken. Based on the fundamental questions that led to the development of the main research objectives, suitable research methods have been developed in order to meet these objectives. Primary data will be collected by use of a mixed methods approach, i.e., questionnaire surveys and focus group discussions/interviews in order to obtain opinions from respondents drawn from targeted ISO construction firms. Most of the data expected to be obtained will be in future be analyzed using statistical software then the findings will be discussed in order to ultimately develop a culture-based QMS framework.

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The development of effective workplace pedagogies is integral to work-integrated and work-based learning. The workplace pedagogies that facilitate and support learning include: activities in which individuals engage such as daily work practices, questioning; observing, and listening; interactions with more experienced workers through coaching and modelling; and referencing documented procedures. Each of these dimensions is significant in enhancing processes of workplace learning. Learning can be optimised when these pedagogies are appropriately embedded in the context of and process of participating in normal work activities. Yet learners need to understand the nature of these pedagogies, and how and for what purposes to use these to achieve a range of learning outcomes. This is because it is the worker-learners who play the key roles in the process and outcomes of learning through work. A pilot study was conducted on students’ conceptions of how each of these dimensions of workplace pedagogy help their learning, by providing examples of learning from these sources; and stating their preferences for learning in the workplace. A sample of seventeen students, enrolled in the second year of a Diploma in Nursing course at a Technical and Further Education institution, participated in a survey intended to capture these conceptions and the importance attached to each of them. The findings indicate that these students have basic understanding of how each of seven workplace pedagogic practices can contribute to their learning. They reported relying mostly on daily practices, observing and listening to others, modelling, coaching, and other workers. Their selection of these contributions emphasise significant opportunities for guided learning by others, yet suggest fewer student-initiated interactions, less intensity in interactions, and likelihood that learning is more passive. The data also suggests that these students rely mostly on using academic learning skill, and limited workplace learning skills. It is proposed, therefore, that the knowledge and understandings about workplace learning and pedagogies might be best embedded in the full curriculum and not become add-on shortly before students go on work placement. This approach will allow students to appreciate the significance and use of workplace pedagogies for learning.

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Building project management requires effective coordination and collaboration between multiple project members. It can be achieved through real time communication flow between all. In present scenario, it can be achieved through adoption of Information and Communication Technologies (ICT). Construction industry primarily comprises small and medium enterprises (SMEs). Also, ICT adoption has been slow in the industry.---------- Research is required to assess the factors that affect ICT adoption at the three levels of industry, organization and people, with focus on SMEs. This paper discusses a component of the research undertaken to study these factors and issues in the context of Indian construction industry. A questionnaire survey was conducted and through quantitative data analysis the extent of adoption of formal Project Management processes, ICT adoption for these processes and factors including perception based factors affecting ICT adoption were studied. Results of data analysis includes identification of issues that require action at the three study levels.---------- The results can be generalized for other countries with due considerations, specifically for countries where the construction industry is similar to Indian construction industry in terms of working methodologies or for large countries.

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Building construction is a highly competitive and risky business. This competitiveness is compounded where conflicting objectives amongst contracting and subcontracting firms sets the stage for an adversarial and potentially destructive approach. There is a need for change in the construction industry—not only to a more cooperative approach to build mutual trust, respect and good faith—but also from a confrontationist and adversarial attitude to a harmonious relationship. It is necessary to change the culture to create a win-win situation. “Strategic Alliances” is one such concept. A strategic alliance is a cooperative arrangement between two or more organisations that forms part of their overall strategies, and contributes to achieving their major goals and objectives. This paper begins with an overview of the Australian building construction industry, then reviews the literature and describes an analysis framework comprising six attributes of strategic alliances—trust, commitment, interdependence, cooperation, communication, and joint problem solving. Given the trend towards greater emphasis on broader contracting firm performance criteria, indicators are proposed as a component of the tender evaluation process for public works.

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There is a need in industry for a commodity polyethylene film with controllable degradation properties that will degrade in an environmentally neutral way, for applications such as shopping bags and packaging film. Additives such as starch have been shown to accelerate the degradation of plastic films, however control of degradation is required so that the film will retain its mechanical properties during storage and use, and then degrade when no longer required. By the addition of a photocatalyst it is hoped that polymer film will breakdown with exposure to sunlight. Furthermore, it is desired that the polymer film will degrade in the dark, after a short initial exposure to sunlight. Research has been undertaken into the photo- and thermo-oxidative degradation processes of 25 ìm thick LLDPE (linear low density polyethylene) film containing titania from different manufacturers. Films were aged in a suntest or in an oven at 50 °C, and the oxidation product formation was followed using IR spectroscopy. Degussa P25, Kronos 1002, and various organic-modified and doped titanias of the types Satchleben Hombitan and Hunstsman Tioxide incorporated into LLDPE films were assessed for photoactivity. Degussa P25 was found to be the most photoactive with UVA and UVC exposure. Surface modification of titania was found to reduce photoactivity. Crystal phase is thought to be among the most important factors when assessing the photoactivity of titania as a photocatalyst for degradation. Pre-irradiation with UVA or UVC for 24 hours of the film containing 3% Degussa P25 titania prior to aging in an oven resulted in embrittlement in ca. 200 days. The multivariate data analysis technique PCA (principal component analysis) was used as an exploratory tool to investigate the IR spectral data. Oxidation products formed in similar relative concentrations across all samples, confirming that titania was catalysing the oxidation of the LLDPE film without changing the oxidation pathway. PCA was also employed to compare rates of degradation in different films. PCA enabled the discovery of water vapour trapped inside cavities formed by oxidation by titania particles. Imaging ATR/FTIR spectroscopy with high lateral resolution was used in a novel experiment to examine the heterogeneous nature of oxidation of a model polymer compound caused by the presence of titania particles. A model polymer containing Degussa P25 titania was solvent cast onto the internal reflection element of the imaging ATR/FTIR and the oxidation under UVC was examined over time. Sensitisation of 5 ìm domains by titania resulted in areas of relatively high oxidation product concentration. The suitability of transmission IR with a synchrotron light source to the study of polymer film oxidation was assessed as the Australian Synchrotron in Melbourne, Australia. Challenges such as interference fringes and poor signal-to-noise ratio need to be addressed before this can become a routine technique.

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Construction clients often use financial incentives to encourage stakeholder motivation and commitment to voluntary higher-order project goals. Despite the increased use of financial incentives, there is little literature addressing means of optimizing outcomes. Using a case study methodology, the examination of a successful Australian construction project demonstrates the features of a positively geared procurement approach that promotes the effectiveness of financial incentives. The research results show that if the incentive system is perceived to be fair and is applied to reward exceptional performance, and not to manipulate, then contractors are more likely to be positively motivated.

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Client-side project managers face challenges in motivating project organisations to pursue exceptional design and construction performance. One approach to improving the motivation of project organisations is by offering a financial incentive reward for the achievement of voluntary performance standards above the minimum required standard. However, little investigation has been undertaken into the features of a successful incentive system as a part of an overall procurement strategy. In response to a lack of information available to client-side project managers tasked with the initial design of an incentive system, the paper explores motivation under a successful incentive and identifies key learnings for client-side project managers to consider when designing incentives. Our findings are based on the results of a large Australian case study which is interpreted against a conceptual framework based on both economic and psychological perspectives of motivation. The results suggest that motivation towards incentive goals is influenced by the value the project organisations place on the incentive reward as a commercial opportunity to increase their profit margins. However, perhaps more important are the relationship management processes that promote commitment to the project; and pride in the achievement of project goals. In the case study, these processes intensified the direct motivational effect of the incentive reward on offer. The findings also highlight the importance of ensuring that incentive goals and performance measurement processes remain relevant to the organisations throughout a project to continuously encourage motivation under changing project conditions.