Reducing the exhaust emissions of an spark ignition engine by means of engine modifications requires consideration of the effects of these modifications on the variations of crankshaft torque and the engine roughness respectively. Only if the roughness does not exceed a certain level the vehicle do not begin to surge. This paper presents a method for controlling the air-fuel ratio for a lean bu...

Fuzzy clustering methods are conveniently employed in constructing a fuzzy model of a system, but they need to tune some parameters. In this research, FCM is chosen for fuzzy clustering. Parameters such as the number of clusters and the value of fuzzifier significantly influence the extent of generalization of the fuzzy model. These two parameters require tuning to reduce the overfitting in the...

a few years after the implementation of computerize maintenance management systems (cmms), showing the analysis results of the collected data in these systems is necessary and important for continuing the usage of these systems. equipment downtime and cost data can identify patterns of equipment faults and equipment costs. it can also show deficiencies in the implementation of maintenance syste...

Water obtained from any source may contain impurities induced by erosion, dissolved minerals, dissolved gases and material produced from organic matter decomposing. If the amount of these substances exceed a certain limit, not only the water would not be potable, but the water containing the material will not be suitable to be used in most applications, or at least before treatment cannot be ap...

this paper submitting the computation of optimize point of ordering in inventory control systems and particularly for continuous review of ordering system (r,q) by fuzzy logic method which similarly can be used for other ordering systems. since in the ordering models we cannot forecast the parameters like cost exactly, we have ambiguity. in this case using precise parameters may cause wrong dec...

this study was conducted to evaluate the share of cost factors affecting on final cost of broiler live weight per kilogram in tehran province. data were collected through questionnaires. farms were divided to three cost ranges: less than 35,000, between 35,000 to 40,000, and over 40000 rails based on production cost per kg of live weight. in this study, water and additives, staff, vaccines, tra...