7,791 research outputs found

    Strategy Selection for Product Service Systems Using Case-based Reasoning

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    A product service system integrates products and services in order to lower environmental impact. It can achieve good eco-efficiency and has received increase in the last decade. This study focuses on strategy selection for product service system design. Case-based reasoning is utilized to provide suggestions for finding an appropriate strategy. To build a case database, successful PSS cases from the literature and websites were collected and formulated. Twelve indices under three categories were analyzed and selected to describe cases. A lot of successful PSS cases and their information were collected. Forty seven cases were used in this study because of the completeness of information. The analytic hierarchic process is used to find the relative weights of the factors that relate to the selection of customers. These weights are used in calculating the similarity in the case-based reasoning process. The successful strategy of the most similar case is extracted and recommended for PSS strategy determination. More than 90% of tested cases obtained an appropriate strategy from the most similar case. Finally, two new products are introduced to find the best strategy for product service system design and development using the proposed case-based reasoning system

    Evaluation of ballast water treatment systems from the perspective of expert seafarers\u27 ship experiences

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    Until recently, the selection of ballast water treatment (BWT) systems was based on a predetermined set of criteria that did not include evaluations for system utilization due to lack of experience. The experience-building phase for the systems began, especially with the entry of the Ballast Water Management Convention into force. For effective assessment and decision-making, the evaluations of expert seafarers responsible for using ballast water treatment systems on-board ships are of paramount importance. This study was completed by evaluating the experience and evaluations of 50 expert seafarers (24 deck personnel and 26 engine personnel) working in a Turkish maritime company in three phases to contribute to the decision-making and system evaluation processes: 1- The failure reports written by the ship personnel of the maritime company were examined, and bilateral interviews with expert seafarers working on these tankers were held; 2- an online questionnaire was prepared and presented to seafarers; 3Analytic hierarchy process (AHP) was used to obtain a common perspective of the seafarers. In this study\u27s first phase, \u27ideal system characteristics\u27 were determined. Based on these characteristics, an online questionnaire was prepared in the second phase of this study and presented to seafarers. In the third phase, a set of six criteria was developed, and the Analytic Hierarchy Process (AHP) was used to obtain the common perspective of 50 participants. Pairwise comparisons revealed that ‘Rare alarms and malfunctions’ was the most important criterion from the perspective of all seafarers and UV-type BWTSs were 1.76 times more preferable than the electrochemical (El-Chem) type BWTSs as a common approach

    An application of fuzzy-AHP to ship operational energy efficiency measures

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    Lowering fuel consumption of ships has gained a great deal of attention in maritime industry with regards to both environmental and economic concerns. The potential for fuel economy in shipping ranging between 25% to 75% is possible by using existing technology and practices and technical improvements in the design of new ship. Despite the existence of many technology and design-based approaches, limitations of emerging these measures has led to discussions about the potential energy savings through operational changes. In this study, operational measures were examined within the scope of Ship Energy Efficiency Management Plan (SEEMP) adopted by International Maritime Organization (IMO). We applied the Analytic Hierarchy Process (Fuzzy-AHP) approach, one of multi-criteria decision making (MCDM) techniques, to prioritize the weight of each measure. Fuzzy AHP effectively reflects the vagueness of human thinking with interval values, and shows the relative importance of operational measures - which can be the fundamental decision making data for decision makers (ships' masters, operating companies and ship owners) - by providing a strategic approach to identify energy efficient solutions

    A NOVEL RISK EVALUATION APPROACH FOR FREQUENTLY ENCOUNTERED RISKS IN SHIP ENGINE ROOMS

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    The purpose of this study is to evaluate risks which are frequently encountered in the engine room on-board. In this context, twenty common risks are assessed using the neutrosophic analytic hierarchy process (N-AHP) and trapezoidal fuzzy technique for order preference by similarity to ideal solution (TrF-TOPSIS). In maritime risk evaluation, since it is frequently required the linguistic assessment of decision-makers to achieve a robust risk assessment tool, neutrosophic sets and fuzzy sets are used together in this study. Neutrosophic sets represent real-world problems effectively by considering all aspects of decision-making situations, (i.e. truthiness, indeterminacy, and falsity). Therefore, AHP is integrated with neutrosophic sets to assign weights of risk parameters initially. Then, the encountered risks are prioritized by TrF-TOPSIS. Finally, preventative actions for the risks have been discussed. In conclusion of the study, it is shown that skin exposure to the fuels/oils, exposure to chemicals and exposure to high pressure and temperature liquids are the most important risks through the engine room on-board. This study both emphasizes the importance of preventing damage to crew in the risk assessment of ship engine rooms and aims to increase the level of safety control and minimize the potential environmental impacts of a ship\u27s damage

    Site Locating For Inspection Posts of Freight Cars in Railway Network Using Analytical Hierarchy Process (AHP) and Geographic Information System (GIS) (CaseStudy: Iranian Railway Network)

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    Freight car inspection and maintenance system have an undeniable role in total costs imposed on system for repair and rehabilitation process of different components of it. This issue shows its importance when railway transportation comes to competition with other modes of transportation. In this competition, lower total cost means more demands and more benefits for optimum systems. Using preventive maintenance methods for rolling stock are among appropriate solutions in order to lower the costs. These methods require to have an exact monitoring system to achieve a reliable scope of system. Inspection posts play an essential role as “wise eyes” on inspection system.Using Analytical Hierarchy Process (AHP) in this article has developed decision tree including goals, criteria, sub criteria and alternatives. The main criteria are 1-traffic, 2-geographical position, 3-loction of station on railway network, and 4-repair and maneuver equipment of station. These criteria and sub criteria have been weighted and quantified using expert’s opinion. The use of Geographical information system, 403 stations had been evaluated with 26 criteria and sub criteria and prioritized. By considering coverage of network in next step, 43 stations are recommended as required station numbers in railway network to provide 70.53% Coverage of railway network traffic

    An Integrated Multicriteria Decision-Making Approach for Collection Modes Selection in Remanufacturing Reverse Logistics

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    Reverse logistics (RL) is closely related to remanufacturing and could have a profound impact on the remanufacturing industry. Different from sustainable development which is focused on economy, environment and society, circular economy (CE) puts forward more requirements on the circularity and resource efficiency of manufacturing industry. In order to select the best reverse logistics provider for remanufacturing, a multicriteria decision-making (MCDM) method considering the circular economy is proposed. In this article, a circularity dimension is included in the evaluation criteria. Then, analytic hierarchy process (AHP) is used to calculate the global weights of each criterion, which are used as the parameters in selecting RL providers. Finally, technique for order of preference by similarity to ideal solution (TOPSIS) is applied to rank reverse logistics providers with three different modes. A medium-sized engine manufacturer in China is taken as a case study to validate the applicability and effectiveness of the proposed framework

    Cost modelling to support optimised selection of the end of life options for automotive components.

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    In automotive sector, the End-of-Life components, especially the uni-material components e.g. steel, plastics etc., traditionally normally go to material recycling. However, this conventional disposing approach has nowadays moved towards the secondary utilization approach which closes the loop in the material flow process, i.e. reuse via remanufacturing, reconditioning, and repairing etc. However, the economic benefit of different End-of-Life options for automotive components remain unclear, there is a need to quantitatively evaluate the economic benefit of different End-of-Life options. This project aims to develop a cost estimation model to assess the cost- effectiveness between recovery alternatives for End-of-Life automotive components. Firstly, the remanufacturing process for automotive components has been modelled consisting different stages and activities involved. Thereafter, the cost elements in each stage and the cost drivers for each cost element have been identified; cost breakdown structure has been established. Next, cost estimation relationships between cost elements and cost drivers have been established. A cost estimation model has been developed, validated and implemented in MS Excel@ platform. Finally, two case studies about comparison of different End-of-Life options for crankshaft and composite oil pan has been performed, it has been shown that the developed cost model can inform which End-of-Life option is more cost effective

    Construction of index system for external risk factors of disease on large-scale farm based on the analytic hierarchy process

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    AbstractAnimal health risk analysis technology on large-scale farm is becoming more important, but the assessment of relevant external risk factors of disease spreading into pig farm is an complex multi-dimensional process. The analytic hierarchy process (AHP) has been accepted as a robust and flexible multi-criteria decision-making tool for dealing with complex decision problems. On this study, The index system of external risk factors on large-scale farm is built based on AHP. The result shows that farm management practices, Biosecurity and site are major risk factors and reveals AHP can be used in animal risk analysis for disease control and prevention

    Multi-criteria decision methods to support the maintenance management of complex systems

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    [ES] Esta tesis doctoral propone el uso de métodos de toma de decisiones multi-criterio (MCDM, por sus iniciales en inglés) como herramienta estratégica para apoyar la gestión del mantenimiento de sistemas complejos. El desarrollo de esta tesis doctoral se enmarca dentro de un acuerdo de cotutela entre la Università degli Studi di Palermo (UNIPA) y la Universitat Politècnica de València (UPV), dentro de sus respectivos programas de doctorado en 'Ingeniería de Innovación Tecnológica' y 'Matemáticas'. Estos programas están estrechamente vinculados a través del tópico MCDM, ya que proporciona herramientas cruciales para gestionar el mantenimiento de sistemas complejos reales utilizando análisis matemáticos serios. El propósito de esta sinergia es tener en cuenta de forma sólida la incertidumbre al atribuir evaluaciones subjetivas, recopilar y sintetizar juicios atribuidos por varios responsables de la toma de decisiones, y tratar con conjuntos grandes de esos elementos. El tema principal del presente trabajo de doctorado es el gestionamiento de las actividades de mantenimiento para aumentar los niveles de innovación tecnológica y el rendimiento de los sistemas complejos. Cualquier sistema puede ser considerado objeto de estudio, incluidos los sistemas de producción y los de prestación de servicios, entre otros, mediante la evaluación de sus contextos reales. Esta tesis doctoral propone afrontar la gestión del mantenimiento a través del desarrollo de tres líneas principales de investigación estrechamente vinculadas. ¿ La primera es el núcleo, e ilustra la mayoría de los aspectos metodológicos de la tesis. Se refiere al uso de métodos MCDM para apoyar decisiones estratégicas de mantenimiento, y para hacer frente a la incertidumbre que afecta a los datos/evaluaciones, incluso cuando están involucrados varios responsables (expertos en mantenimiento) en la toma de decisiones. ¿ La segunda línea desarrolla análisis de fiabilidad para sistemas complejos reales (también en términos de fiabilidad humana) sobre cuya base se debe implementar cualquier actividad de mantenimiento. Estos análisis consideran la configuración de fiabilidad de los componentes del sistema en estudio y las características específicas del entorno operativo. ¿ La tercera línea de investigación aborda aspectos metodológicos importantes de la gestión de mantenimiento y enfatiza la necesidad de monitorizar el funcionamiento de las actividades de mantenimiento y de evaluar su efectividad utilizando indicadores adecuados. Se ha elaborado una amplia gama de casos de estudio del mundo real para evaluar la eficacia de los métodos MCDM en el mantenimiento y así probar la utilidad del enfoque propuesto.[CA] Aquesta tesi doctoral proposa l'ús de mètodes de presa de decisions multi-criteri (MCDM, per les seves inicials en anglès) com a eina estratègica per donar suport a la gestió del manteniment de sistemes complexos. El desenvolupament d'aquesta tesi doctoral s'emmarca dins d'un acord de cotutela entre la Università degli Studi di Palermo (UNIPA) i la Universitat Politècnica de València (UPV), dins dels seus respectius programes de doctorat en 'Enginyeria d'Innovació Tecnològica' i ' Matemàtiques '. Aquests programes estan estretament vinculats a través del tòpic MCDM, ja que proporciona eines crucials per gestionar el manteniment de sistemes complexos reals utilitzant anàlisis matemàtics profunds. El propòsit d'aquesta sinergia és tenir en compte de forma sòlida la incertesa en atribuir avaluacions subjectius, recopilar i sintetitzar judicis atribuïts per diversos responsables de la presa de decisions, i tractar amb conjunts grans d'aquests elements en els problemes plantejats. El tema principal del present treball de doctorat es la gestió de les activitats de manteniment per augmentar els nivells d'innovació tecnològica i el rendiment dels sistemes complexos. Qualsevol sistema pot ser considerat objecte d'estudi, inclosos els sistemes de producció i els de prestació de serveis, entre d'altres, mitjançant l'avaluació dels seus contextos reals. Aquesta tesi doctoral proposa afrontar la gestió del manteniment mitjançant el desenvolupament de tres línies principals d'investigació estretament vinculades. ¿ La primera és el nucli, i il·lustra la majoria dels aspectes metodològics de la tesi. Es refereix a l'ús de mètodes MCDM per donar suport a decisions estratègiques de manteniment, i per fer front a la incertesa que afecta les dades/avaluacions, fins i tot quan estan involucrats diversos responsables (experts en manteniment) en la presa de decisions. ¿ La segona línia desenvolupa anàlisis de fiabilitat per a sistemes complexos reals (també en termes de fiabilitat humana) sobre la qual base s'ha d'implementar qualsevol activitat de manteniment. Aquestes anàlisis consideren la configuració de fiabilitat dels components del sistema en estudi i les característiques específiques de l'entorn operatiu. ¿ La tercera línia d'investigació aborda aspectes metodològics importants de la gestió de manteniment i emfatitza la necessitat de monitoritzar el funcionament de les activitats de manteniment i d'avaluar la seva efectivitat utilitzant indicadors adequats. S'ha elaborat una àmplia gamma de casos d'estudi del món real per avaluar l'eficàcia dels mètodes MCDM en el manteniment i així provar la utilitat de l'enfocament proposat.[EN] This doctoral thesis proposes using multi-criteria decision making (MCDM) methods as a strategic tool to support maintenance management of complex systems. The development of this doctoral thesis is framed within a cotutelle (co-tutoring) agreement between the Università degli Studi di Palermo (UNIPA) and the Universitat Politècnica de València (UPV), within their respective programmes of doctorates in 'Technological Innovation Engineering' and 'Mathematics'. Regarding this thesis, these programmes are closely linked through the topic of MCDM, providing crucial tools to manage maintenance of real complex systems by applying in-depth mathematical analyses. The purpose of this connection is to robustly take into account uncertainty in attributing subjective evaluations, collecting and synthetizing judgments attributed by various decision makers, and dealing with large sets of elements characterising the faced issue. The main topic of the present doctoral work is the management of maintenance activities to increase the levels of technological innovation and performance of the analysed complex systems. All kinds of systems can be considered as objects of study, including production systems and service delivery systems, among others, by evaluating their real contexts. Thus, this doctoral thesis proposes facing maintenance management through the development of three tightly linked main research lines. ¿ The first is the core and illustrates most of the methodological aspects of the thesis. It refers to the use of MCDM methods for supporting strategic maintenance decisions, and dealing with uncertainty affecting data/evaluations even when several decision makers are involved (experts in maintenance). ¿ The second line develops reliability analyses for real complex systems (also in terms of human reliability analysis) on the basis of which any maintenance activity must be implemented. These analyses are approached by considering the reliability configuration of both the components belonging to the system under study and the specific features of the operational environment. ¿ The third research line focuses on important methodological aspects to support maintenance management, and emphasises the need to monitor the performance of maintenance activities and evaluate their effectiveness using suitable indicators. A wide range of real real-world case studies has been faced to evaluate the effectiveness of MCDM methods in maintenance and then prove the usefulness of the proposed approach.Carpitella, S. (2019). Multi-criteria decision methods to support the maintenance management of complex systems [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/11911
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