Sharif Digital Repository

Automatic translation of a high-level specification language to an executable implementation would be highly useful in maximizing the benefits of formal methods. We will introduce a set of translation functions to fill the specification-implementation gap in the domain of database applications. We chose Z, SQL and Delphi languages to illustrate our methodology. We extend Delphi libraries to support mathematical objects exist in Z. Then, based on the extended libraries, we extract the translation functions from Z to Delphi. The translation functions from Z to SQL are more easily extracted, because the mathematical foundation of Z has many properties in common with SQL. Based on the extracted... 

Nowadays spam has become as a universal problem which all email users are familiar with it. Studies show that a large proportion of sent emails are spam. Obviously it results in wasting a vast range of resources. There is different ways to fight spam; each of them has its own strengths and weaknesses. The most common filtering technique is content based filtering. This problem has been addressed as a text classification problem. Two main defect of spam filtering techniques are manually definition of rules and circumventing them, one solution for overcoming this problem is applying machine learning algorithms. Spam classification using machine learning techniques is very successful and... 

Object oriented analysis and design hase become the paradigm of choice for many software builders. For, it has filled the gap between the problem domain and its solution. However, most of object oriented methods can not prove their model against the software specification and do not ensure that they realize what the customer needs. Formal method is one of the methods used for building softwares. Since a software is specified accurately by this method, the specification can be used to build the software in addition to being used as a test for the final software. A specification can be refined to code step by step. Since an object oriented model is close to problem domain in real world, a... 

Samples of INCONEL 718 were levitated and melted in a slag by the application of an electromagnetic field. The effects of temperature, time and slag composition on the inclusion content of the samples were studied thoroughly. Samples were compared with the original alloy to study the effect of the process on inclusions. Size, shape and chemical composition of remaining nonmetallic inclusions were investigated. The samples were prepared by Standard Guide for Preparing and Evaluating Specimens for Automatic Inclusion Assessment of Steel (ASTM E 768-99) method and the results were reported by means of the Standard Test Methods for Determining the Inclusion Content of Steel (ASTM E 45-97).... 

The oil refining industry, as the first oil supply chain, is of great importance. By examining the issue of the Iranian Oil Refining Industry, using the game theory, one can find an accurate analysis of the barriers to the development of this industry. For this purpose, the main factors affecting the oil refining industry, the government and the refinery's owner, are modeled and their benefits are considered. By examining the relationship between these actors and their actions, the following strategies are proposed to improve the administration and regulate the Iranian oil refining industry:
1- Refining feed prices, according to the quality of crude oil (sulfur content and API... 

Much research has been done in the electromagnetic levitation process, but there is not any information about carrying out this process to refine steel continuously. In this study inclusion behavior of molten steel in contact with slag, in the presence of an electeomagnetic field, has been investigated. The steel sample, in an elliptical section, was levitated in an electromagnetic field, in a chamber containing slag consisting of CaF2-Al2O3-CaO, in order to achieve a continuous process, and changes in time, temperature and slag composition parameters in this process were studied. According to ASTM E45 standard, after performing metallographic process on melted samples, using light...