Search results for "Fuzzy"

Defining and measuring the network flexibility of humanitarian supply chains: insights from the 2015 Nepal earthquake

2019

International audience; The efficient and effective response to disasters critically depends on humanitarian supply chains (HSCs). HSCs need to be flexible to adapt to uncertainties in needs, infrastructure conditions, and behavior of other organizations. The concept of ‘network flexibility’ is, however, not clearly defined. The lack of an unanimous definition has led to a lack of consistent understanding and comparisons. This paper makes a threefold contribution: first, it defines the concept of network flexibility for HSC in the context of sudden onset disasters. Second, it proposes a framework to measure network flexibility in HSCs. Third, we apply our framework to the 2015 Nepal earthqu…

Companies’ Selection Methods for Inclusion in Sustainable Indices: A Fuzzy Approach

2017

Sustainability indices handle concepts which are both, of numerical and non-numerical nature. In this context, the use of Fuzzy Logic is highly useful as allows a more faithful representation of reality. Usually these indices follow a three-step process to define sustainable investment universes. First step consists of sustainability assessment. In the second step, assets are rated based on the previously assessed sustainability scores and finally, best assets are selected. This last step relies on the construction of a global score reflecting the performance of the assets in main sustainability dimensions. In this Chapter we are concerned with the third step of the selection process. We re…

Trattamento dell'incertezza epistemica nell'analisi affidabilistica

TREEZZY2, a Fuzzy Logic Computer Code for Fault Tree and Event Tree Analyses

2004

In conventional approach to reliability analysis using logical trees methodologies, uncertainties in system components or basic events failure probabilities are approached by assuming probability distribution functions. However, data are often insufficient for statistical estimation, and therefore it is required to resort to approximate estimations. Moreover, complicate calculations are needed to propagate uncertainties up to the final results. In our work, in order to take account of the uncertainties in system failure probabilities, the methodology based on fuzzy sets theory is used both in fault tree and event tree analyses. This paper just presents our work in this issue, which resulted…

Full- and reduced-order filter design for discrete-time T-S fuzzy systems with time-varying delay

2012

This paper is focused on the problem of ℋ ∞ filtering for a class of discrete-time T-S fuzzy time-varying delay systems. Our interest is how to design full- and reduced-order filters that guarantee the filtering error system to be asymptotically stable with a prescribed ℋ ∞ performance. Sufficient conditions for the obtained filtering error system are proposed by applying an input-output approach and a two-term approximation method, which is employed to approximate the time-varying delay. The corresponding full and reduced-order filter design is cast into a convex optimization problem, which can be efficiently solved by standard numerical algorithms.

Filtering with dissipativity for T-S fuzzy systems with time-varying delay: Reciprocally convex approach

2013

This paper is focused on the problem of reliable filter design with strictly dissipativity for a class of discrete-time T-S fuzzy time-delay systems. Our attention is paid on the design of reliable filter to ensure a strictly dissipative performance for the filtering error system. By employing the reciprocally convex approach, a sufficient condition of dissipativity analysis is obtained for T-S fuzzy delayed systems with sensor failures. A desired reliable filter is designed by solving a convex optimization problem.

Allocation of logistic risk-investment in public-private-partnership – use of fuzzy TOPSIS method

2018

Appropriate risk assessment related to the project, and then its distribution between partners is the core of cooperation in the framework of public-private partnership (PPP). Risk analysis for investment project in the PPP formula includes: preliminary identification of risks associated with the investment, preliminary assessment and forecast of probability of occurrence of risks in the recommended option of investment implementation, initial analysis of the distribution of risks between a public and private entity depending on the legal and organizational model adopted, including the determination of the appropriate separation between the parties to the contract. The article presents the …

A Simultaneous Approach for IMS Design: a Possibility Based Approach

1999

IMS investments are characterised by high fixed costs and long life cycles. On the other hand, their redditivity and risk coverage depend on their manufacturing efficiency that is mainly defined during the design phase by fixing the system configuration. Due to the flexibility required to IMS, system configuration depends not only from technological information, such as product routing table and service times, but also from marketing data such as the typology of products to be manufacture and their production volumes. Moreover, the evaluation of the redditivity and the risk of the investment depends on market information such as product prices as well. Such interdependencies make the invest…

Early Vision and Soft Computing

2002

The term soft-computing has been introduced by Zadeh in 1994. Soft-computing provides an appropriate paradigm to program malleable and smooth concepts. For example, it can be used to introduce flexibility in artificial systems and possibly to improve their Intelligent Quotient. Aim of this paper is to describe the applicability of soft-computing to early vision problems. The good performance of this approach is claimed by the fact that digital images are examples of fuzzy entities, where geometry of shapes are not always describable by exact equations and their approximation can be very complex.

Selecting between CNC turning centers using a combined AHP and fuzzy approach

2019

Abstract CNC turning centers (CNCTC) are designed to perform simple turning operations, for parts having a symmetry axis. However, the flexibility of these machine-tools is increasing rapidly. Supplementary modules, such as Y-axis and driven tools, which allow the user to perform milling operations, are fitted on CNCTC. Selecting the proper CNCTC, out of a great number of commercially available solution has become a very difficult task. A combined approach using Analytic Hierarchy Process (AHP) and fuzzy logic is proposed, to assist the decision-making process of choosing between three variants of CNCTC.