Reliability degradation prediction of photovoltaic modules based on dependability methods

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hadef Hefaidh ◽  
Djebabra Mébarek ◽  
Belkhir Negrou ◽  
Zied Driss
Keyword(s):  
System Performance ◽  
Design Methodology ◽  
Fault Tree Analysis ◽  
Reliability Prediction ◽  
Accelerated Tests ◽  
Tree Analysis ◽  
Content Type ◽  
Photovoltaic Modules ◽  
Pv Modules ◽  
Criticality Analysis

PurposeThe reliability prediction is among the most important objectives for achieving overall system performance, and this prediction carried out by anticipating system performance degradation. In this context, the purpose of this research paper is to development of methodology for the photovoltaic (PV) modules' reliability prediction taking into account their future operating context.Design/methodology/approachThe proposed methodology is framed by dependability methods, in this regard, two methods of dysfunctional analysis were used, the Failure Mode and Effects Criticality Analysis (FMECA) method is carried out for identification of the degradation modes, and the Fault Tree Analysis (FTA) method is used for identification the causes of PV modules degradation and the parameters influencing its degradation. Then, based on these parameters, accelerated tests have been used to predict the reliability of PV modules.FindingsThe application of the proposed methodology on PWX 500 PV modules' in different regions of Algeria makes it possible to predict its reliability, taking into account the future constraints on its operation. In this case, the temperature and relative humidity vary from one region to another was chosen as constraints. The results obtained from the different regions confirms the reliability provided by the designer of the Saharan cities Biskra, In Salah, Tamanraset, and affirms this value for the two Mediterranean cities of Oran and Algiers.Originality/valueThe proposed methodology is developed for the reliability prediction of the PV modules taking into account their future operating context and, the choice of different regions confirms or disproves the reliability provided by the designer of the PV modules studied. This application confirms their performance within the framework of the reliability prediction.

Design and fabrication of a lower limb exoskeleton to assist in stair ascending

2019 ◽  
Vol 46 (2) ◽  
pp. 290-299 ◽  
Author(s):  
Payman Joudzadeh ◽  
Alireza Hadi ◽  
Bahram Tarvirdizadeh ◽  
Danial Borooghani ◽  
Khalil Alipour
Keyword(s):  
Lower Limb ◽  
System Performance ◽  
Design Methodology ◽  
Stair Climbing ◽  
Robot Design ◽  
Disabled People ◽  
Content Type ◽  
Lower Limb Exoskeleton ◽  
Knee Braces ◽  
Novel Design

Purpose This paper aims to deal with the development of a novel lower limb exoskeleton to assist disabled people in stair ascending. Design/methodology/approach For this purpose, a novel design of a mixture of motors and cables has been proposed for users to wear them easily and show the application of the system in stair climbing. Findings One of the prominences of this study is the provided robot design where four joints are actuated with only two motors; each motor actuates either the knees or ankles. Another advantage of the designed system is that with motors placed in a backpack, the knee braces can be worn under clothes to be concealed. Finally, the system performance is evaluated using electromyography (EMG) signals showing 28 per cent reduction in energy consumption of related muscles. Originality/value This investigation deals with the development of a novel lower limb exoskeleton to assist disabled people in stair ascending.

A fuzzy fault tree analysis based risk assessment approach for enterprise resource planning projects

2018 ◽  
Vol 35 (5) ◽  
pp. 1115-1141 ◽  
Author(s):  
Mina Moeinedini ◽  
Sadigh Raissi ◽  
Kaveh Khalili-Damghani
Keyword(s):  
Risk Factors ◽  
Enterprise Resource Planning ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Resource Planning ◽  
Successful Implementation ◽  
Tree Analysis ◽  
Content Type ◽  
Cause And Effect ◽  
Fuzzy Fault Tree Analysis

Purpose Enterprise resource planning (ERP) is assumed as a commonly used solution in order to provide an integrated view of core business processes, including product planning, manufacturing cost, delivery, marketing, sales, inventory management, shipping and payment. Selection and implementation of a suitable ERP solution are not assumed a trivial project because of the challenging nature of it, high costs, long-duration of installation and customization, as well as lack of successful benchmarking experiences. During the ERP projects, several risk factors threat the successful implementation of the project. These risk factors usually refer to different phases of the ERP projects including purchasing, pilot implementation, teaching, install, synchronizing, and movement from old systems toward new ones, initiation and utilization. These risk factors have dominant effects on each other. The purpose of this paper is to explore the hybrid reliability-based method is proposed to assess the risk factors of ERP solutions. Design/methodology/approach In this regard, the most important risk factors of ERP solutions are first determined. Then, the interactive relations of these factors are recognized using a graph based method, called interpretive structural modeling. The resultant network of relations between these factors initiates a new viewpoint toward the cause and effect relations among risk factors. Afterwards, a fuzzy fault tree analysis is proposed to calculate Failure Fuzzy Possibility (FFP) for the basic events of the fault tree leading to a quantitative evaluation of risk factors. Findings The whole proposed method is applied in a well-known Iranian foodservice distributor as a case study. The most impressive risk factors are identified, classified and prioritized. Moreover, the cause and effect diagram between the risk factors are identified. So, the ERP leader can plan a low-risk project and increase the chance of success. Originality/value According to the authors’ best knowledge, such approach was not reported before in the literature of ERP risk assessments.

scholarly journals Evaluations on adequacy and utility of Failure Modes and Effects and Criticality Analysis and Fault Tree Analysis methodologies applied to civil RPAS systems

2018 ◽  
Vol 233 ◽  
pp. 00002 ◽  
Author(s):  
Federica Bonfante ◽  
Matteo D. L. Dalla Vedova ◽  
Paolo Maggiore
Keyword(s):  
Information Science ◽  
Failure Modes ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Economic Benefits ◽  
Tree Analysis ◽  
Research Activities ◽  
Remotely Piloted Aircraft ◽  
Critical Issues ◽  
Criticality Analysis

This paper is on the Failure Modes and Effects and Criticality Analysis and Fault Tree Analysis methodologies applied to the equipment and functional subsystems of Remotely Piloted Aircraft Systems (RPAS). Such aerial vehicles have been used almost exclusively for military purposes until the first decade of the 2000s. The debate then was focused both on technical and regulatory issues and research activities. Thanks to this renewed interest on unmanned systems and thanks to relatively recent improvements in information science, telecommunication, electronics and material science a strong awareness on the potential extension of unmanned technologies to civil applications arose up. A variety of economic benefits has been recognized by the aviation community from the civil use of RPAS, but, due to the absence of the pilot on board both military and civilian RPAS have always been relegated to fly into segregated airspaces. Technical potentialities of RPAS will be fully exploited integrating them into controlled airspaces in a reliable and safe way. This paper shows an example of application of FMECA and FTA to RPAS and discuss the most critical issues related to the performed analyses as well as possible future developments of this work.

Design and implementation of a directly cooled PV/T

2015 ◽  
Vol 13 (3) ◽  
pp. 369-379
Author(s):  
Busiso Mtunzi ◽  
Edson L. Meyer
Keyword(s):  
Hybrid System ◽  
Design Methodology ◽  
Air Cooling ◽  
Water Cooling ◽  
Content Type ◽  
Water Ingress ◽  
Design And Implementation ◽  
Pv Module ◽  
Pv Modules ◽  
Practical Implications

Purpose – The purpose of this paper is to design and implement a directly cooled photovoltaic thermal (PV/T) hybrid system. Design/methodology/approach – The research design subjects, instruments and methods that were used to collect data are as detailed in the paper. Two polycrystalline photovoltaic (PV) modules were used in this study. Findings – The directly water-cooled PV module (PV/T) was found to operate better as compared to a naturally cooled module for the first three months. The PV/T initially operated at a higher electrical efficiency for 87 per cent of the day. The monthly energy-saving efficiency of the PV/T was found to be approximately 61 per cent, while the solar utilisation of the naturally cooled PV module M1 was found to be 8.79 per cent and that of M2 was 47.93 per cent. Research limitations/implications – The major limitation was the continued drop in efficiency after the first three months of the PV/T placed outdoors. The fall in the efficiency was attributed to water ingress. Practical implications – Direct water cooling of PV modules is possible, only that a better sealing is needed to prevent water ingress. Originality/value – PV air cooling has been researched on. Use of water as a cooling medium has been carried out using serpentine pipes or riser tube, and no direct water cooling on the back of the module has been researched on.

scholarly journals Managing the tension between opposing effects of explainability of artificial intelligence: a contingency theory perspective

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Babak Abedin
Keyword(s):  
Artificial Intelligence ◽  
System Performance ◽  
Fuzzy Systems ◽  
Data Analytics ◽  
Design Methodology ◽  
Contingency Theory ◽  
Content Type ◽  
The Social ◽  
Opposing Effects ◽  
Practical Implications

PurposeResearch into the interpretability and explainability of data analytics and artificial intelligence (AI) systems is on the rise. However, most recent studies either solely promote the benefits of explainability or criticize it due to its counterproductive effects. This study addresses this polarized space and aims to identify opposing effects of the explainability of AI and the tensions between them and propose how to manage this tension to optimize AI system performance and trustworthiness.Design/methodology/approachThe author systematically reviews the literature and synthesizes it using a contingency theory lens to develop a framework for managing the opposing effects of AI explainability.FindingsThe author finds five opposing effects of explainability: comprehensibility, conduct, confidentiality, completeness and confidence in AI (5Cs). The author also proposes six perspectives on managing the tensions between the 5Cs: pragmatism in explanation, contextualization of the explanation, cohabitation of human agency and AI agency, metrics and standardization, regulatory and ethical principles, and other emerging solutions (i.e. AI enveloping, blockchain and AI fuzzy systems).Research limitations/implicationsAs in other systematic literature review studies, the results are limited by the content of the selected papers.Practical implicationsThe findings show how AI owners and developers can manage tensions between profitability, prediction accuracy and system performance via visibility, accountability and maintaining the “social goodness” of AI. The results guide practitioners in developing metrics and standards for AI explainability, with the context of AI operation as the focus.Originality/valueThis study addresses polarized beliefs amongst scholars and practitioners about the benefits of AI explainability versus its counterproductive effects. It poses that there is no single best way to maximize AI explainability. Instead, the co-existence of enabling and constraining effects must be managed.

Probabilistic Design Methodology and the Application of Probabilistic Fault Tree Analysis to Machine Design

1995 ◽  
Author(s):  
Landon C. Onyebueke ◽  
Chinyere Onwubiko ◽  
Feng C. Chen
Keyword(s):  
Design Methodology ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Computer Code ◽  
Spur Gear ◽  
Probabilistic Design ◽  
System Construction ◽  
Tree Analysis ◽  
Design Variables ◽  
Structural Variables

Abstract This paper gives an overview of Probabilistic Design Methodology (PDM) with emphasis on quantification of the effects of uncertainties for structural variables and the evaluation of failure probability. The application of Probabilistic Fault Tree Analysis (PFTA) to the design of a shaft carrying a spur gear is also presented. The PFTA includes the development of a fault tree to represent the system, construction of an approximation function for bottom events, computation of sensitivity factors of design variables, and the calculation of the system reliability. The computer code employed for the analyses is known as “Numerical Evaluation of Stochastic Structures Under Stress” (NESSUS). NESSUS is developed under NASA probabilistic structural analysis program.

Understanding and visualizing schedule deviations in construction projects using fault tree analysis

2020 ◽  
Vol 27 (9) ◽  
pp. 2501-2522 ◽  
Author(s):  
Pei-Yuan Hsu ◽  
Marco Aurisicchio ◽  
Panagiotis Angeloudis ◽  
Jennifer Whyte
Keyword(s):  
Construction Projects ◽  
Complex Structure ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Causal Connection ◽  
Critical Systems ◽  
Tree Analysis ◽  
Content Type ◽  
Schedule Delay ◽  
Depth Analysis

PurposeDelays in construction projects are both disruptive and expensive. Thus, potential causes of schedule deviation need to be identified and mitigated. In previous research, delay factors were predominantly identified through surveys administered to stakeholders in construction projects. Such delay factors are typically considered individually and presented at the same level without explicitly examining their sequence of occurrence and inter-relationships. In reality, owing to the complex structure of construction projects and long execution time, non-conformance to schedule occurs by a chain of cascading events. An understanding of these linkages is important not only for minimising the delays but also for revealing the liability of stakeholders. To explicitly illustrate the cause–effect and logical relationship between delay factors and further identify the primary factors which possess the highest significance toward the overall project schedule delay, the fault tree analysis (FTA) method, a widely implemented approach to root cause problems in safety-critical systems, has been systematically and rigorously executed.Design/methodology/approachUsing a case study, the in-depth analysis for identifying the most fundamental delay factors has been fulfilled through FTA's tree structure. The logical deduction for mapping and visualising the chronological and cause–effect relationships between various delay factors has been conducted through the logical gate functions of FTA based on the data collected from the site event log, pre-fabricated structural component manufacturing log and face-to-face interview with project stakeholders.FindingsThe analysis identified multiple delay factors and showed how they are linked logically and chronologically from the primary causes to the ultimate undesired event in a rigorous manner. A comparison was performed between the proposed FTA model and the conventional investigation method for revealing the responsibility employed in the construction industry, consisting of event logs and problem reports. The results indicate that the FTA model provides richer information and a clearer picture of the network of delay factors. Importantly, the ability of FTA in revealing the causal connection between the events leading to the undesired delays and in comprehending their prominence in the real-world construction project has been clearly displayed.Originality/ valueThis study demonstrates a new application of FTA in the construction sector allowing the delay factors to be understood and visualised from a new perspective. The new approach has practical use in finding and removing root causes of the delay, as well as clarifying the attribution of responsibility that causes the delay.

An investigation of the influence of managerial factors on industrial accidents in the construction industry using the gray FTA method

2016 ◽  
Vol 6 (1) ◽  
pp. 96-109 ◽  
Author(s):  
Manouchehr Omidvari ◽  
Seyyed Morteza Abootorabi ◽  
Hossein Mehrno
Keyword(s):  
Construction Industry ◽  
Design Methodology ◽  
Fault Tree Analysis ◽  
Strong Relationship ◽  
Uncertain Information ◽  
Industrial Accidents ◽  
Content Type ◽  
Probability Of Occurrence ◽  
Work Related ◽  
Statistical Report

Purpose – The statistical report published by the Iranian Social Security Organization in 2012 showed that, of all industries, the construction industry is associated with the highest number of work-related accidents. Furthermore, as this sector contains a large human workforce, identification of the factors contributing to the occurrence of such accidents is vital. The paper aims to discuss these issues. Design/methodology/approach – Furthermore, as this sector contains a large human workforce, identification of the factors contributing to the occurrence of such accidents is vital. In the present study, such factors were initially identified, after which the most important of these, managerial factors, were selected. Subsequently, the identification of the causes of the managerial factors was carried out with the use of the fault tree analysis (FTA) method and application of OR and AND entries. Findings – Since it is difficult to determine the probability of occurrence of events in this industry with certainty, and because gray numbers (numbers of which the exact value is unknown, and which represent uncertain information) have a strong relationship with human expressions, the probability of occurrence of the main undesired events was also evaluated using the gray numbers as input entries, in addition to ranking the probability of occurrence of intermediate events. Originality/value – The findings revealed that FTA using gray numbers is a useful and effective tool in risk assessment.

An evaluation of EIA system performance in Turkey in the context of procedural effectiveness

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Deniz Çolakkadıoğlu
Keyword(s):  
Environmental Impact ◽  
Impact Assessment ◽  
Environmental Impact Assessment ◽  
System Performance ◽  
Design Methodology ◽  
Assessment Tool ◽  
Content Type ◽  
Administrative Process ◽  
The World ◽  
The Usa

Purpose In Turkey, where the environmental impact assessment (EIA) has been applied since 1993, there have been numerous amendments in the legal and administrative process of the EIA. This study aims to evaluate the effectiveness of those amendments to the EIA process. Design/methodology/approach This paper evaluated EIA system performance in the context of procedural effectiveness in Turkey from the day implementation was begun. From its beginning to the present day, the positive and negative developments at the EIA process in Turkey caused by the amendments were evaluated and at which stages. Measures recommended increasing the effectiveness of each of the EIA systems were also identified. Findings As the EIA Directive first came into force in the USA in 1970, EIA procedures have been widely adopted throughout the world. Although it has been implemented for many years, expectations regarding the EIA process have still not been realized which has forced countries to conduct studies to increase the effectiveness of the EIA process. Turkey, like other countries that are implementing the EIA, acknowledges that the EIA is a significant impact assessment tool and continues its studies to implement this system effectively. In this respect, in Turkey, where the EIA has been applied since 1993, there have been numerous amendments in the legal and administrative process of the EIA. Originality/value The results obtained from this study were expected to facilitate the evaluation of the EIA process in Turkey and to guide other similar countries.

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