86 research outputs found

    Analyse inter-critère basée sur les fonctions de croyance pour l'analyse GPS

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    International audienceIn this paper we present an application of a new Belief Function-based Inter-Criteria Analysis (BF-ICrA) approach for Global Positioning System (GPS) Surveying Problems (GSP). GPS surveying is an NP-hard problem. For designing Global Positioning System surveying network, a given set of earth points must be observed consecutively. The survey cost is the sum of the distances to go from one point to another one. This kind of problems is hard to be solved with traditional numerical methods. In this paper we use BF-ICrA to analyze an Ant Colony Optimization (ACO) algorithm developed to provide near-optimal solutions for Global Positioning System surveying problem

    Hybrid Taguchi-GRA-CRITIC Optimization Method for Multi-Response Optimization of Micro-EDM Drilling Process Parameters

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    In this study, an attempt is made to investigate how the operational parameters such as capacitance, voltage, feed rate, and rotating speed affect the material removal rate, tool wear, overcut, and taper angle for micro-EDM drilling of aluminium 6061 utilizing brass C360 electrode. A novel Taguchi-GRA-CRITIC hybrid optimization methodology is used to obtain the optimal combination of micro-EDM drilling process parameters. The experiment was designed using the Taguchi L18 orthogonal array, and responses were recorded for each experiment. Grey Relational Analysis (GRA) is applied to improve the multi-response of the planned experiment. The weighting values corresponding to various responses are determined using CRITIC (criterion importance through intercriteria correlation) analysis. The hybrid methodology determines the best combination of process parameters for different responses. ANOVA was used to discover the most critical parameters. Finally, confirmation experiments were conducted with optimal parameters to identify improvement in grey relational grade over the initial parameters. The study\u27s findings indicate that, compared to the initial process parameter setting, the grey relational grade (GRG) increased by 92.36% with the optimal parameter setting

    Functional and structural leaf plasticity determine photosynthetic performances during drought stress and recovery in two platanus orientalis populations from contrasting habitats.

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    In the context of climatic change, more severe and long-lasting droughts will modify the fitness of plants, with potentially worse consequences on the relict trees. We have investigated the leaf phenotypic (anatomical, physiological and biochemical) plasticity in well-watered, drought- stressed and re-watered plants of two populations of Platanus orientalis, an endangered species in the west of the Mediterranean area. The two populations originated in contrasting climate (drier and warmer, Italy (IT) population; more humid and colder, Bulgaria (BG) population). The IT control plants had thicker leaves, enabling them to maintain higher leaf water content in the dry environment, and more spongy parenchyma, which could improve water conductivity of these plants and may result in easier CO2 diffusion than in BG plants. Control BG plants were also characterized by higher photorespiration and leaf antioxidants compared to IT plants. BG plants responded to drought with greater leaf thickness shrinkage. Drought also caused substantial reduction in photosynthetic parameters of both IT and BG plants. After re-watering, photosynthesis did not fully recover in either of the two populations. However, IT leaves became thicker, while photorespiration in BG plants further increased, perhaps indicating sustained activation of defensive mechanisms. Overall, our hypothesis, that plants with a fragmented habitat (i.e., the IT population) lose phenotypic plasticity but acquire traits allowing better resistance to the climate where they became adapted, remains confirmed

    An integrated CRITIC-COPRAS approach for multi-response optimization on AWJM of hybrid filler–reinforced polymer composite and its surface integrity

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    Composites have gained acceptance in an extensive range of applications owing to their unique characteristics. But, machining of these materials is often challenging due to improved bonding between matrix and fibre when fillers are added. Since the machinability is an important aspect for any material for its successful utilization, it is essential to analyse the effect of secondary phase on machinability. However, investigations on the effect of fillers on machinability of polymer composites are minimal. In this research, hybrid fillers, namely boron nitride (BN) and montmorillonite (MMT) nanoclay, were added to epoxy/glass fibre composite through compression moulding, in which quantity of MMT is fixed and BN is varied from 2 to 6 wt%. Abrasive water jet machining (AWJM) is a leading method for machining polymer composites in which transverse speed, stand-off distance, pump pressure and filler percentage are key factors and are considered as input variables. To assess the machinability, material removal rate (MRR), surface roughness (Ra) and kerf taper (Kt) are chosen as response variables. Experimental planning is done through Taguchi method, and Criteria Importance Through Intercriteria Correlation (CRITIC)-weighted Complex Proportional Assessment (COPRAS) technique is utilized for optimization. The results revealed that addition of BN reduces the MRR while it improves the surface finish and reduces the Kt. Transverse speed has the most influence over all the considered output responses, stand-off distance and water pressure mainly affect the MRR and Ra while filler addition mainly affects the Kt. The hybrid CRITIC-COPRAS approach–recommended optimal control factors resulted in 16.20 mm 3/min MRR with 0.29° Kt and 3.86 µm Ra. The recommended optical condition can be utilized for effective machining of polymer composite with MMT/BN fillers.</p

    A Novel Risk Assessment Model for Prefabricated Building Construction Based on Combination Weight and Catastrophe Progression Method

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    To reduce the construction risk of prefabricated building projects, a prefabricated building construction risk assessment index system with five first-level indicators and 21 second-level indicators was established based on human, machine, material, management, and environmental factors. By combining the analytic hierarchy process (AHP), CRiteria Importance through Intercriteria Correlation (CRITIC), and catastrophe theory, a risk assessment model of prefabricated building construction based on a combination weighting and catastrophe progression method was constructed. The effectiveness of the assessment model using the combination weighting and catastrophe progression method was verified through case analysis. The results show the following: (1) The quality of the prefabricated components, the standardization degree of the prefabricated components, and the environment of the installation working space in the construction risk assessment indicators of prefabricated buildings obtained by the AHP-CRITIC weighting method have higher weights. (2) Four prefabricated construction enterprises under China State Construction Corporation are evaluated, and the evaluation results effectively evaluate the project risk situation before an accident occurred, achieving the goal of improving the risk management efficiency. (3) The AHP-CRITIC weighting method can reflect the fuzziness of the construction risk of the evaluated project, effectively reduce information loss, and thus make the evaluation results more accurate. The conclusions have important practical significance for improving the construction risk management of prefabricated buildings

    INFLUENCE OF THE “PUSH & FLICK” METHODOLOGY ON THE ACCURACY OF THE INDOOR HOCKEY PENALTY CORNER SHOOTING

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    The penalty corner (PC) is one of the most important game situations in hockey (both outdoors and indoors), which results in 30 – 40% of all goals. The aim of this paper is to study the influence of the quasi-experimental methodology on the dynamics in the development of indicators characterizing the accuracy of shooting when performing PC in the potentially effective goal zones. Through the application of InterCriteria Analysis (ICrA), the research team sought to establish relationships and directions of dependencies between indicators reflecting the accuracy of zone shooting. Four elite female indoor hockey players from the team of the National Sports Academy in Bulgaria, participants in the European Indoor Hockey Clubs Challenge, were involved in the examination sessions. According to the requirements of the quasi-experimental “Push & Flick” methodology, the duration of the specialized training was set to 16 weeks. Each player performed 4,800 shootings, or approximately 300 shootings each week. Tests were carried out at the beginning (the first week) and at the end (the sixteenth week) of the experiment in order to determine the accuracy of the shooting – push/flick from a penalty corner spot (9 meters, central from the goal line). We used InterCriteria Analysis and Variance Analysis to analyze the results. The results of the study provide valuable information related to the training and specialization of elite hockey players profiled in the execution of a penalty corne

    Optimization of a Multiple Injection System in a Marine Diesel Engine through a Multiple-Criteria Decision-Making Approach

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    [Abstract] In this work, a numerical model was developed to analyze the performance and emissions of a marine diesel engine, the Wärtsilä 6L 46. This model was validated using experimental measurements and was employed to analyze several pre-injection parameters such as pre-injection rate, duration, and starting instant. The modification of these parameters may lead to opposite effects on consumption and/or emissions of nitrogen oxides (NOₓ), carbon monoxide (CO), and hydrocarbons (HC). According to this, the main goal of the present work is to employ a multiple-criteria decision-making (MCDM) approach to characterize the most appropriate injection pattern. Since determining the criteria weights significantly influences the overall result of a MCDM problem, a subjective weighting method was compared with four objective weighting methods: entropy, CRITIC (CRiteria Importance Through Intercriteria Correlation), variance, and standard deviation. The results showed the importance of subjectivism over objectivism in MCDM analyses. The CRITIC, variance, and standard deviation methods assigned more importance to NOₓ emissions and provided similar results. Nevertheless, the entropy method assigned more importance to consumption and provided a different injection pattern

    Multi-criteria analysis to determine the most appropriate fuel composition in an ammonia/diesel oil dual fuel engine

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    [Abstract] The possibility to employ alternative fuels is gaining special interest in the marine sector. There are several suitable candidates for traditional fossil fuels substitution. Among them, ammonia is a promising solution that allows progress on decarbonization since the ammonia molecule does not contain carbon. Hence, the present work analyzes the use of ammonia as a potential fuel for a marine engine. Particularly, a dual fuel mode ammonia/diesel oil operation is proposed. As expected, the carbon dioxide emissions are reduced as the proportion of ammonia is increased. Nevertheless, other non-desirable substances are generated such as non-reacted ammonia, NOx and N2O. Due to these opposing effects, a multi-criteria analysis is proposed to characterize the most appropriate proportion of ammonia in the fuel. The environmental damage of the different pollutants was considered. Due to the important environmental adverse effects of NOx and N2O, only a maximum 20% ammonia percentage on the fuel was obtained as the most appropriate option. A higher ammonia content leads to excessive concentrations of NOx and N2O being emitted to the environment

    Algorithms for probabilistic uncertain linguistic multiple attribute group decision making based on the GRA and CRITIC method: application to location planning of electric vehicle charging stations

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    Electric vehicles (EVs) could be regarded as one of the most innovative and high technologies all over the world to cope with the fossil fuel energy resource crisis and environmental pollution issues. As the initiatory task of EV charging station (EVCS) construction, site selection play an important part throughout the whole life cycle, which is deemed to be multiple attribute group decision making (MAGDM) problem involving many experts and many conflicting attributes. In this paper, a grey relational analysis (GRA) method is investigated to tackle the probabilistic uncertain linguistic MAGDM in which the attribute weights are completely unknown information. Firstly, the definition of the expected value is then employed to objectively derive the attribute weights based on the CRiteria Importance Through Intercriteria Correlation (CRITIC) method. Then, the optimal alternative is chosen by calculating largest relative relational degree from the probabilistic uncertain linguistic positive ideal solution (PULPIS) which considers both the largest grey relational coefficient from the PULPIS and the smallest grey relational coefficient from the probabilistic uncertain linguistic negative ideal solution (PULNIS). Finally, a numerical case for site selection of electric vehicle charging stations (EVCS) is designed to illustrate the proposed method. The result shows the approach is simple, effective and easy to calculate

    Electronic Device Selection in Industrial Products and Machinery Industry: Comparative Analysis with Ocra and Maut Method

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    The diversity and abundance of product alternatives lead to vagueness on decisions related to procurement, production, and R &amp; D management processes along with other decisions taken within the company and render purchasing, production and R&amp;D decision processes, much more effortful. As choosing appropriate and effective decisions within purchasing, production, R&amp;D, and all other departments are of great importance in today’s competitive business environment, firms are strongly encouraged to concentrate on their decision processes. Within the scope of this study, the purchase decisions of electronic device alternatives are being analysed in industrial products and machinery industry with OCRA method. The importance levels of evaluation criteria for the purchase are obtained out of 100 points. These importance levels are then being used in OCRA method in an attempt to evaluate various electronic device alternatives. In order to scrutinize the results, it can be said that the same data set is compatible with MAUT, which is another multi-criteria decision making method. Information regarding the evaluation criteria as well as alternatives of electronic device has been gathered through focus group study that includes marketing and purchasing managers. The results provide useful information for the sector
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