Sharif Digital Repository

The quality characteristics of both manufacturing and service industries include not only the variables but the attributes as well. While a substantial research have been performed on auto-correlated variables, no attempt has been fulfilled for auto-correlated attributes. Ignoring the imbedded autocorrelation structure in constructing control charts cause not only the in-control run length to decrease, but also the false alarms to increase. To overcome these shortcomings, in this research, an auto-regressive (AR) vector first models the autocorrelation structure of the process data. Then, a modified Elman neural network is developed to generate simulated data using the ARTA algorithm. Next,... 

The picosecond (ps) pulses in a synchronously pumped optical parametric oscillator (SPOPO) is generated by a 20W and 81.1 MHz Yb fiber laser at 1064nm, providing 11.7 W of total average power in near to mid-IR at 73% efficiency so that the signal pulse with a wavelength of 1560 nm and 7.1W average power and 3330 nm idler pulse with an average power of about 4.6W has been produced. The optical parametric oscillator (OPO), based on a 50 mm MgO:PPLN crystal with 5 gratings which is capable of withstanding large average powers without thermal effects.
The duration of these ultrashort infrared signal pulse generated by the described SPOPO is measured by using homemade interferometric... 

A statistically-based method has been developed for automated identification of steady state. The method is computationally inexpensive when compared to conventional techniques. The R-statistic is dimensionless and independent of the measurement level. Because it is a ratio of estimated variances, it is also independent of the process variance. Simulations show that for recommended critical values are also effectively independent of the magnitude and distribution of the noise.
A fuzzy-logic-based methodology for on-line steady state and transient state identification is introduced. Although steady state identification is complicated by the presence of noise, fuzzy logic can help capture... 

Nowadays,The use of employ of Simulation techniques to estimate different determine characteristics and analyze of any kinds of various systems performance measures has increaseds drastically. The output analysis in simulation plays a key role to obtain the estimates. Consequently, in a given simulation project, whether it is terminating or steady state, the use of statistical approaches to analyze output data derived by running the simulation model is inevitable.During a given Simulation project, most of time is devoted to build, and run a model; however, to analyze the outputs of model plays a key role to obtain desire goals of project. Consequently, in a predefine simulation project,... 

Nowadays due to the advancement in technology, most of the production processes consist of several dependent stages and the quality characteristics of products at each stage depends not only on the operation at the current stage but also to the quality characteristics at the upstream stages. In other words, the disturbance in the quality characteristics of each stage would propagate to the downstream stages and affects the quality of the products at downstream stages. This property is referred to as the cascade property of multistage processes. However, the most of the conventional SPC tools were developed based on the assumption of processes with single stage or processes with multiple... 

Nowadays, due to the advancement in manufacturing technology and increasing use of information technology in the services and industries, most of production proccess consist of complex and high-dimensional data. These processes include multivariate processes, complex profiles and multistage processes. In some quality control applications, processes consist of multiple components, stations or stages to finish the final product or service which are called multistage processes. In addition, some quality characteristics in each stage can be represented by a relationship between a response variable and one or more explanatory variables which is named as profile. In this research, a general model... 

In this thesis, we investigate the imprint of gravitational microlensing effects on the light curves of Gamma-ray burst (GRBs) to estimate compact object mass in the form of black holes in the Universe. We assume a point mass model of the gravitational lens and a geometry in which the source−lens are at the same direction that manifests in the GRB light curve as superimposed peaks by the time delay between the two images and searches the Fermi/GBM catalog. According to the sensitivity of our detection method, we consider microlensing events with a time delay on the order of 10 s due to point-mass lenses in the range of 〖10〗^5- 〖10〗^7 M_(⊙ ). We found one microlensed GRB candidate out of...