Sharif Digital Repository

Ways to reduce an airline's cost has been studied for years. In fact, in order to achieve this goal, ones need to know different types of airline's costs including; fuel and oil, maintenance, Ticketing, passenger services, etc. and their impact on the total cost of an airline. According to announcement of ICAO [1], "maintenance cost (about 11% of total cost) is the second major cost after fuel and oil". Therefore, this may attract airline owners' attention to find ways to control maintenance cost and eventually the total cost of an airline. Though, there are many systematic approaches to analyze cost reduction and making policies, in this article, SD modeling is applied to develop a... 

In this research, a web-based simulator is developed, which can be used for generating image sequences of moving spermatozoa cells. It can be used for assessment of multiple object tracking algorithms, especially Computer Aided Sperm Analysis (CASA) systems. The developed software has many useful parameters such as blurring images or adding noise and it also gives full control of sperm counts and types. To illustrate performance of the developed simulator, three parameters (spermatozoa population, standard deviation of Gaussian blur filter and noise intensity) have been swept and the results of three different multiple object tracking algorithms were compared as an application of this... 

Lumbar disc diseases are the commonest complaint of Lower Back Pain (LBP). In this paper, a new method for automatic diagnosis of lumbar disc herniation is proposed which is based on clinical Magnetic Resonance Images (MRI) data. We use T2-W sagittal and myelograph images. Our method uses Otsu thresholding method to extract the spinal cord from MR images of Lumbar disc. In the next step, a third-order polynomial is aligned on the extracted spinal cords, and in the end of preprocessing step all the T2-W sagittal images are prepared for extracting disc boundary and labeling. After labeling and extracting a ROI for each disc, intensity and shape features are used for classification. The... 

The Atmospheric Lifetime (ALT) of a compound represents the potential for the atmospheric accumulation of chemicals. Chemicals with a long lifetime are more resistant to natural decomposition and remain in the environment for a longer period. Minimum Ignition Energy (MIE) is one of the most important properties when evaluating hazardous chemicals. Despite the significance of these environment and safety-related properties, currently, there are no group contribution (GC) models that enable their predictive modeling. The present research aims at filling this gap. To this end, experimental data were collected from literature and the GC model parameters were estimated using the weighted... 

Analogous to Computer-Aided Software Engineering (CASE), which aims to facilitate Software Engineering through specialized tools, Computer-Aided Method Engineering (CAME) strives to support a wide range of activities carried out by method engineers. Although there is consensus on the importance of tool support in method engineering, existing CAME environments are incomplete prototypes, each covering just a few steps of the method engineering process. This paper summarizes the history and the state of the practice in CAME technology, and provides criteria-based critique on existing CAME environments, thus highlighting their strengths and weaknesses. © 2008 Springer-Verlag Berlin Heidelberg  

A hybrid method consisting of principal component analysis (PCA), multiple linear regressions (MLR), and artificial neural network (ANN) was developed to predict the retention time of 149 C3 - C12 volatile organic compounds for a DB-1 stationary phase. PCA and MLR methods were used as feature-selection tools, and a neural network was employed for predicting the retention times. The regression method was also used as a calibration model for calculating the retention time of VOCs and investigating their linear characteristics. The descriptors of the total information index of atomic composition, IAC, Wiener number, W, solvation connectivity index, Xlsol, and number of substituted aromatic... 

This article describes an automatic reactor power control system for VVER-1000 reactor and reports simulation analysis results for a typical daily load follow operation. The associated reactor control algorithm is called `mode G' that uses a heavy-worth bank (H-bank) dedicated to axial power shape control and the light-gray banks (G-banks) for reactor power change and reactivity compensation. The simulation results for daily load follow operation in three burnup states of first cycle illustrate that the load follow capability of VVER-1000 reactors using this algorithm will be improved