1,824 research outputs found

    Managing the Influence of Stakeholders on the Scope of Major Construction Projects to Prevent Scope Creep in the BIM Era

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    The present PhD thesis is centred on investigating the challenge of scope creep within construction projects, denoting the phenomenon of an uncontrolled enlargement of project scope without essential adaptations. Stakeholders are identified as a major source of uncertainty and requests for changes in scope, which can result in risky events. Therefore, an overarching framework is needed to effectively resolve the problem of scope creep caused by stakeholder influence. The adoption of Building Information Modelling (BIM) is suggested as an effective methodology for the streamlined management of information in construction projects, thus enabling project managers to develop an appropriate solution for the identified problem. To develop this framework, a meta-analysis approach and case study strategy is employed to analyse and synthesise secondary data collected from the PMBOK GUIDE’S (PMI, 2017) project management processes, BIM-related standards, and six case study projects. The objective is to identify essential processes and activities, their sequence and interdependencies, problematic issues, and best practices. The outcome of the research is the creation of a Process Framework designed to address the problem of scope creep triggered by stakeholder influence. The elements and concepts of this framework are verified by undertaking semi-structured interviews with five practitioners from the construction and infrastructure industry. The Process Framework functions as a unifying mechanism that combines project management and BIM processes, thereby ensuring coordination and integration towards the overarching objective of managing stakeholder influence on project scope and mitigating scope creep. Additionally, this research contributes to the understanding of the relationship between BIM documents and project management processes. The study explores how BIM fits within project management processes and identifies the benefits of BIM for the resolution of issues in construction projects, including end product visualization, clash detection, and efficient information sharing. This study provides an extensive and meticulous analysis of scope creep within construction projects and presents a pragmatic framework for dealing with this issue

    Migrating to Cloud-Native Architectures Using Microservices: An Experience Report

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    Migration to the cloud has been a popular topic in industry and academia in recent years. Despite many benefits that the cloud presents, such as high availability and scalability, most of the on-premise application architectures are not ready to fully exploit the benefits of this environment, and adapting them to this environment is a non-trivial task. Microservices have appeared recently as novel architectural styles that are native to the cloud. These cloud-native architectures can facilitate migrating on-premise architectures to fully benefit from the cloud environments because non-functional attributes, like scalability, are inherent in this style. The existing approaches on cloud migration does not mostly consider cloud-native architectures as their first-class citizens. As a result, the final product may not meet its primary drivers for migration. In this paper, we intend to report our experience and lessons learned in an ongoing project on migrating a monolithic on-premise software architecture to microservices. We concluded that microservices is not a one-fit-all solution as it introduces new complexities to the system, and many factors, such as distribution complexities, should be considered before adopting this style. However, if adopted in a context that needs high flexibility in terms of scalability and availability, it can deliver its promised benefits

    Mechanical performance of concrete with partial replacement of sand by sewage sludge ash

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    The production of sewage sludge from waste water treatment plants is increasing all over the world. Disposal of sewage sludge is a serious environmental problem. If we think of the areas needed for sludge ash disposal, we clearly understand the importance of reusing sewage sludge ash in concrete. This paper presents results related to the replacement of sand by sewage sludge ash. The sludge was characterized for chemical composition (XRF analysis), crystalline phases (XRD analysis) and pozzolanic activity. The effects of incineration on crystal phases of dry sludge were investigated. Two (W/C) ratios (0.55 and 0.45) and three sludge percentages (5%, 10% and 20%) by cement mass were used. The mechanical performance of SSAC at different curing ages (3, 7, 28 and 90 days) was assessed by means of mechanical tests. Results show that sewage sludge ash leads to a reduction in density and mechanical strength. Results also show that concrete with 20% of sewage sludge ash and W/C=0.45 has a 28 day compressive strength of almost 30MPa

    Mechanical performance of concrete with partial replacement of sand by sewage sludge ash from incineration

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    "Advanced Materials Forum VI , vol. 730-732"The production of sewage sludge from waste water treatment plants is increasing all over the world. Disposal of sewage sludge ash is a serious environmental problem. If we think of the areas needed for sludge ash disposal, we clearly understand the importance of reusing sewage sludge ash in concrete. This paper presents results related to the replacement of sand by sewage sludge ash. The sludge was characterized for chemical composition (XRF analysis), crystalline phases (XRD analysis) and pozzolanic activity. The effects of incineration on crystal phases of dry sludge were investigated. Two (W/C) ratios (0.55 and 0.45) and three sludge percentages (5%, 10% and 20%) by cement mass were used. The mechanical performance of SSAC at different curing ages (3, 7, 28 and 90 days) was assessed by means of mechanical tests. Results show that sewage sludge ash leads to a reduction in density and mechanical strength. Results also show that concrete with 20% of sewage sludge ash and W/C=0.45 has a 28 day compressive strength of almost 30MPa

    Frequency-dependent anti arrhythmic effects of crataegus monogyna on the extracellular field potential recordings in the rabbit atrioventricular node, an experimental model of AF

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    Introduction: Despite extensive studies that have been performed on the effects of Crataegus monogyna in cardiovascular diseases, only few investigations have addressed the antiarrhythmic properties of this plant. Aims of the present study were: 1) To determine the protective role of methanolic extract of C. monogyna on the rate-dependent model and the concealed conduction of the AV node. 2) To explore the role of Na+-K+ ATPase in the protective role of C. monogyna Methods: Male New Zealand rabbits (1.5-2kg) were used in all experiments. Stimulation protocols were used to measure basic and rate-dependent AV nodal properties (recovery, atrial fibrilation and zone of concealment) in two groups (N=14). In the first group, all the stimulation protocols were performed before and after the administration of different concentrations of C. monogyna extract (n=7), while in the second group (n=7), all stimulation protocols were carried out in the presence of ouabaine (0.05 μM) and the plant extract. Results: Basic and rate-dependent properties of the AV node were inhibited after the addition of the extract of C. monogyna to Kerebs Henselite solution. At the maximum concentration of C. monogyna (30 mg/l), WBCL cycle length was significantly increased from 156.5±3.4 to 173±5.8 ms and the nodal functional refractory period was prolonged from 164.4±4.1 to 182.7±3.8 ms (P<0.05). Significant decreases of ventricular rhythm were recorded in both selective concentrations of the plant extract. The depressant electrophysiological effect of C. monogyna on the AV node was not abolished by ouabaine, a selective inhibitor of Na+-K+ ATPase enzyme. Conclusion: The results showed a potential anti-arrhythmic and protective effect for C. monogyna. The effect of the plant extract in increasing nodal refractory period and widening of the concealment zone might be the major mechanisms involved. The protective role of C. monogyna was not related to the Na+-K+ ATPase activity

    Inheritance of RAPD marker in female grass carp (Ctenopharyngodon idella), male bighead carp (Hypophthalmichthys nobilis) and their F1 hybrids

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    Genetic variation and inheritance of randomly amplified polymorphic DNA (RAPD) markers in female grass carp (Ctenopharyngodon idella) and male bighead carp (Hypophthalmichthys nobilis) and their F1 offspring hybrid have been studied. For this purpose, genomic DNA was extracted from muscle tissue according to phenol-chloroform method, and six decamer primers were used for amplifying polymorphic DNA. Results from 77 produced bands showed that all RAPD bands pattern of parents were present in F1 offspring hybrid, which indicated the high influence and dominance of the mentioned markers. The low difference in polymorphisms in used markers between F1 offspring hybrid and parents shows that parents are heterozygous in some loci, which can cause low difference in hybrids of two distinct genera. Although our results revealed that RAPD markers had a suitable efficiency in distinguishing parents from F1 hybrids, genetic diversity of triploid and diploid F1 hybrid were not detected by introduced primers

    AUV location detection in an enclosed environment

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    Normally, experiments are done in a controlled environment so that different systems under test can be isolated. The added benefit is that the sensors used are a lot more accurate under controlled conditions. In the experiments perform on underwater robot localization, this was not the case. The sonar localization equipment use perform flawlessly in open water as it was designed to do, but poorly in an indoor pool. It is believed that the sonar had too much power causing too many reflections in the enclosed space. Unfortunately the experiments are better done in a pool so as to control the elements under test. This paper is the search to improve the equipment\u27s accuracy in an enclosed environment by attempting to reduce the power of the sonar via mechanical means

    Survey of the robust control of robots

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    Browse Conference Publications \u3e American Control Conference, ... Page Help Survey of the Robust Control of Robots This paper appears in: American Control Conference, 1990 Date of Conference: 23-25 May 1990 Author(s): Abdallah, C. CAD Laboratory for Systems and Robotics, Electrical and Computer Engineering Department, University of New Mexico, Albuquerque, NM 87131. Dorato, P. ; Jamshidi, M. On Page(s): 718 - 721 Product Type: Conference Publications 4790827 searchabstract .Abstract In this survey, we discuss current approaches to the robust control of the motion of robots and summarize the available literature on the subject. The three major designs discussed are the Linear-Multivariable Approach, the Passivity approach and the Variable-Structure approach. The survey is limited to rigid robots and nonadaptive controllers
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