Sharif Digital Repository

XML has been emerged as a de facto standard for data exchange and information transition over computer networks including Web. On the other hand by the growing use of sensors and data streams over computer networks, the usage of XML data format for data streams between data and processing units like sensors and information centers is growing. In this thesis first we do a survey on XML query processing and optimization and after that we propose methods for optimizing query processing over XML data streams based on data stream unique attributes and incremental completeness of XML data trees for increasing the speed of processing and decreasing the amount of memory that processing needs. For... 

Infrastructural costs of data management, have led people and organizations to outsource their data. This approach is facing with some significant security challenges and risks. The goal of this research, is to present an architecture for secure outsourcing of data in a way that used methods, storage processes, query processing methods and access control mechanisms work together to preserve confidentiality and integrity of outsourced data. In this architecture, the main challenge is transparent placement of some components between client and server in order to prevent user from being aware of communication with a secured server. In order to create this degree of transparency, we need to pay... 

This project aims to highlight vision related tasks centered around "car". First, we gathered a dataset of 4343 front view car images, captured from the streets of Iran and Syria during daylight, the images of which are all manually cropped around their corresponding accurately chosen bounding boxes. we also extracted seven parts (i.e. left and right front lights, left and right mirrors, bumper, plate, and air intake) from each car image in the dataset. Our dataset is suitable for developing and testing bounding box extraction algorithms, holistic and part based analyses, occlusion handling algorithms, etc. next, we utilized Viola-Jones Detector to develop a system for car detection, in... 

SQL injection is one of the most important security threats in web applications with backend SQLbased database. An attacker can abuse an application’s vulnerability to change the queries sent from the application to the database. Many techniques and frameworks have been proposed for detecting and preventing SQL injection. But most of them cannot detect all types of SQL injection such as second-order attacks. In this thesis, we propose a new method to detect and prevent all types of this attack. The proposed method is a kind of anomaly-based intrusion detection methods and could be considered as a proxy between the application server and the database server. The proposed method, can detect... 

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... 

While data outsourcing provides some benefits, it suffers from new privacy and security concerns, mainly about the confidentiality and integrity of the stored sensitive data, as well as enforcing access control policies. Current solutions to these aims are not comprehensive and consider only one aspect of security requirements. A secure DBMS architecture is introduced that simultaneously considers confidentiality, integrity and access control enforcement requirements. The transparency of security functions from data owner, service providers, and applications facilitates the operationality of the solution.Additionally, a new indexing technique for character encrypted data is proposed that... 

Recently XML has become a standard for data representation and the preferred method of encoding structured data for exchange over the Internet. Moreover it is frequently used as a logical format to store structured and semi-structured data in databases. In this research we focus on semantic modeling for XML data and we propose a model-driven approach for modeling and designing XML databases. In the approach data is modeled without considering representation and implementation details in a platform independent model.
We use Object-Role Modeling as the platform independent model. We specify a formal meta-model of this model in Alloy and we validate instance models by checking... 

Protecting sensitive data stored in database systems, especially in outsourced ones, has become a major concern in many organizations. One of the main possible solutions is to encrypt data before storing them on databases. Bucket-based encryption is among different approaches proposed to accomplish this goal which besides its various benefits, suffers from generating false-positive results. Multi-join queries are one of the most important operations in database systems and their usage grows rapidly in comparison to other types of queries by increasing the size of stored information. While using the decision support systems and data mining solutions are growing continuously, executing... 

Text-to-speech synthesis, one of the key technologies in speech processing, is a technique for generating speech signal from arbitrarily given text with target speaker’s voice characteristics and various speaking styles and emotional expressions. Statistical parametric speech synthesishasrecently been shown to be very effective in generating acceptable synthesized speech. Therefore, in this study,the main focus is on one of the instances of these techniquescalled hidden Markov model-based speech synthesis. In text-to-speech systems, it is desirable to synthesize high quality speech using a small amount of speech data; this goal would be achieved by employing speaker adaptation framework and... 

The quality assessment of image and video data has became an important and challenging problem in the fields of image/video processing. Oftentimes, the images/videos files are designed to be viewed by a human observer. Further, the number and size of such files
are growing everyday. Thus, computer-assisted monitoring of the quality has emerged as the only possible solution for this challenge. In this thesis, we shall first review the existing techniques for no-reference(blind) quality assessment of image and video data. Next, we propose some new approaches for the no-reference quality assessment of image and video data in-the-wild. In the case of images, our contributions consist of two... 

In this study, using the MCNPX computer code based on the Monte Carlo method, the properties of protection against gamma-rays of the glass system with the combination of (55-x)Bi2O3-15Pb3O4-20Al2O3-10ZnO-xTiO2 with certain concentrations (x= 0, 5, 10, 15, 20, 25, 30 and 35 mol percent) and in nano and micro dimensions by calculating several parameters related to photon attenuation such as half value layer (HVL), Tenth value layer (TVL), mean free range (MFP), mass attenuation coefficient (m), linear attenuation coefficient (l), effective atomic number (Zeff) and buildup factor (BF) for We investigated different energy levels in the range of 1500-100 keV. To verify the simulation results,... 

Majority of the oil and gas reservoirs, in the main hydrocarbon production regions around the world, are naturally fractured reservoirs. Fractures play an important role in reservoir fluid flow either in the form of high permeable complex conduits or strong permeability anisotropies. Realistic characterization of naturally fractured reservoirs requires an exhaustive understanding of fracture connectivity and fracture pattern geometry. These subsequently demand description of many fracture parameters such as density (intensity), spacing, orientation, size and aperture. Therefore, a first step in fractured reservoirs characterization is the static geometric modeling of the subsurface fracture... 

Nowadays, NGOs have a special roll in solving social problems in the world. In regards to the developing state of these organizations in Iran, the need of adopting a systematic approach in managing these organizations, is bold. Renewing of the old methods of work in these organizations, is an aid to removing the barriers of development faced by these organizations.
In this regard, this thesis subjects the reengineering of business processes of Rayehe Charity Foundation which is an NGO dealing with empowerment of households women.
After studding the literature of reengineering, the thesis continues on introducing the organization and its activities in more detail. It categorizes... 

One important problem in query optimization in centralized and decentralized databases is optimizing queries containing common sub-expressions, known as multi-query optimization. In processing these queries, the goal is to process a group of queries together and find a global execution plan with minimum cost for the query set. In most of researches which have approached this problem the focus were on exhaustive algorithms. Since size of the problem space for these algorithms grows exponential with query set size, these approaches are impractical. In this research we have presented six algorithms based on Ant Colony Optimization metaheuristic. We have compared the efficiency of these methods...