The computation of latest starting times and floats of activities in networks with uncertain durations, represented by means of interval and fuzzy numbers, is investigated.

in this paper, we introduce and study the concepts of $mathcal{i}_2$-convergence, $mathcal{i}_2^{*}$-convergence for double sequences of fuzzy real numbers, where $mathcal{i}_2$ denotes the ideal of subsets of $mathbb n times mathbb n$. also, we study some properties and relations of them.

the methods of assessing the individuals’ performance usually applied in practice are based on principles of the bivalent logic (yes-no). however, fuzzy logic, due to its nature of including multiple values, offers a wider and richer field of resources for this purpose. in this paper we use principles of fuzzy logic in developing a new method for assessing the performance of groups of individua...

Manpower recruitment and training in uncertain and turbulent environments is a challenge to decision makers in large organizations. In the absence of numerical precision on market growth and the ensuing manpower demand, designing manpower planning policies is vital. Often times, companies incur losses due to overstaffing and/or understaffing. For instance, organizations lose business when criti...

Firefly algorithm is a swarm-based algorithm that can be used for solving optimization problems. In this paper, we focus on image clustering algorithm using the fuzzy set of possible solution is incorporated into the original firefly to improve the performance. The movement of the firefly still follows the original pattern but they are updated according fuzzy c-means algorithm. All method, k-me...

There exists a vast literature about the di erentiabil ity of fuzzy valued mappings see for instance Dubois and Prade Puri and Ralescu Goetschel and Voxman or Kaleva One of the main problems in working with di erentials of fuzzy valued mappings is that the usual class of fuzzy sets of R does not con gure a vectorial space with respect to the sum and the product by a scalar induced by Zadeh s Ex...

seismic hazard assessment like many other issues in seismology is a complicated problem, which is due to variety of parameters affecting the occurrence of earthquake. uncertainty, which is a result of vagueness and incompleteness of the data, should be considered in a rationale way. herein, fuzzy set theory is used to take into account the uncertainty existed in the seismic hazard analysis. the...

The 3 degree of freedom (3-DOF) helicopter system is a typical higher-order times, instability, multi-variable, nonlinear and strong coupling control system. This paper presents the analysis of the mathematical model and the basic principle of PID control and fuzzy PID control, which are based on 3-DOF helicopter systems. In allusion to balance control of 3-DOF helicopter system, PID controller...

In this paper, the authors develop a model to estimate future performance of construction projects. For the purpose of estimation, fuzzy times series models are used as an effective approach in estimation process. Furthermore, linguistic terms are applied to interpret the fuzzy-based results. The proposed model can assists project managers to develop their knowledge concerning the future aspect...

In this paper, a multi-objective genetic algorithm is proposed to deal with a real-world fuzzy job shop scheduling problem. Fuzzy sets are used to model uncertain due dates and processing times of jobs. The objectives considered are average tardiness and the number of tardy jobs. Fuzzy sets are used to represent satisfaction grades for the objectives taking into consideration the preferences of...