Sharif Digital Repository

Given two speech segments, the task of speaker verification is defined as determining whether or not both of them have been uttered by the same person. Most of the new approaches in speaker verification are based on Total Variability Space which is the result of applying a factor analysis on GMM mean supervector space. The representation of speech with arbitrary duration in this space is called i-vector.
In this thesis, first the basics of speaker verification is described and i-vector approaches are explained in more details. Then, a method for improving accuracy of Cosine Similarity Scoring is proposed which normalize the raw score using the score of test utterance against a model- and... 

Distributed computation has an important role in data mining. Data mining, usually requires a lot of resources both in terms of storage space and computing time. To reach scalability, some mechanisms for the distribution of work is required. Moreover, in many systems today, data is distributed in several databases. In this case, due to traffic overload in network, transferring all data to a central server and applying process centrally is inefficient and is subject to privacy issues. Distributed data mining provides some techniques for efficient mining in decentralized mode. Identifying frequent itemsets is one of the important branches of data mining. Frequent patterns are set of items,... 

It's impossible to check all inputs of a software program due to infinite input domain, therefore the domain should be somehow restricted. One popular approach to do so, is input space partitioning. In this approach, the input domain has been modeled and partitioned into some equivalent classes or blocks. Using these blocks, it's possible to select one sample from each one and reduce the number of test cases to a small desirable number. To automate this approach, it's essential to firstly define the software requirements specification in a well-defined machine understandable template, then with processing this document we can detect program’s functionality and testable functions. Our goal in... 

Mutation testing is known to be one of the best strategies to improve the quality of test suites, consequently the quality of the software. However, some challenges make mutaton testing unpractical. One of the main challenges confronting mutation testing is that it demands exhustive computation and is time consuming because of the large number of mutants that need to be compiled and executed on the test cases of the test suite. Many researches have been conducted to reduce the number of mutants without losing the main characteristics of the all possible mutants. Most of these researches select the mutants without considering the characteristics of the test suite, therefore the reduced set of... 

The presented work provides a calculus for refining an object oriented formal specification to an object oriented code. A refinement calculus provides a framework to produce executable code from a specification while preserving its correctness. Eiffel Refinement Calculus is the most complete work in this domain which is studied in this research.
The Formal specification language which is considered for this purpose is .JML to specify executable code in .Java language. For this calculus some refinement laws are pre- sented and their proofs is given by weakest precondition predicate transformer, a work which was not considered in Eiffel Refinement Calculus. The constructs which are used in... 

Software development process is a base ground for all software activities and ensures all aspects of the software. No quality is guaranteed without a definite process. Model-Driven Software Development process proposes an industrial method for software companies to produce the required software through model(s) and tools. On the other hand, Software Product Line imposes a set of frameworks and principles. As a result a tangible decrement of development time and cost along with an increment of quality is achieved. Mixing both processes creates a stronger industrial process in order to decrease the development time and cost. In this thesis, through a survey on both of the processes and related... 

Less than a decade ago, Test Driven Development (TDD) emerged as a quality assurance approach and applied in agile software developments. In this method, test cases act as software development driver and a new piece of code is added just to satisfy the corresponding test case in the test repository. Although the results of applying TDD show its success in software quality promotion, but the method suffers from some limitations and shortcomings that make its usage hard in complicated and enterprise software projects, particularly in the industry. The goal of the following research is to mitigate the drawbacks of TDD and improve the method in order to make it more applicable for complicated... 

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... 

Nowadays, small and big businesses do their best to automate their business process by using a workflow management system. Therefore, these systems play a key role in IT. By expansion of the business and ever-changing rules and procedures of organization, the need for consecutive changes to workflow management systems arises. The most challenging part of this change is the state of running instances. Previous solutions put the challenges of migrating instances, dealing with their inconsistencies and runtime errors on the users. It is worth noting that there are a few tools which consider instance migrations, but most of them lack a comprehensive viewpoint. Related solutions are often based... 

A workflow management system is a software system which manages and coordinates the operational tasks of an organization. Typically, the def­ inition of a workflow involves human and computer resources and tools on various geographic locations, and thus the concerns of distributed systems are one of the main challenges in this domain. Following this,allocating various resources to different tasks of a workflow and schedul­ ing them in a manner which satisfies some predefined constraints is one of the new and fundamental challenges in this field.The main goal of this research is to design an agent-oriented workflow system which utilizes a novel method for resource allocation and schedul­ ing... 

As the increased use of workflow engine based systems in various domains, quality assurance and testing them has become critical. The majority of these systems are designed and implemented by a workflow language, so testing these systems is highly dependent of workflow language. In this thesis the common domain of business processes is chosen. In this area, little researches have examined the implemened processes with the second version of BPMN modeling language, and most methods, examined another language called BPEL. For this reason and due to the increased use of BPMN language because of its unique characteristics, this study focuses on testing of systems implemented with this language.... 

Aspect-Oriented Programming is a software engineering paradigm that offers new constructs, such as join points, pointcuts, advices and aspects in order to improve separation of crosscutting concerns. The new constructs bring new type of programming faults with respect to crosscutting concerns, such as incorrect pointcuts, advice or aspect precedence. In fact, existing object-oriented testing techniques are not adequate for testing aspect-oriented programs. As a result, new testing techniques must be developed. In this paper, an approach based upon UML sequence diagrams for testing aspect- oriented program is presented. The proposed approach focuses on integration of one or several... 

In the current decade there has been research works around adopting agile methodologies for software product line engineering. However, the emphasis has been on the process part of the methodology and the main product which is the source code has been neglected.The prevalent modeling and implementation method of software product line is the featureoriented method. The concept of ”Feature-to-code mapping” is introduced in the implementation phase which recently novel approaches have been proposed to realize it.Despite superiority of the novel approaches in this field, prevalent industrial product lines still use C language and map features to code by leveraging traditional preprocessors of C... 

Software Development is an engineering activity and similar to other engineering activities requires a process. Model-driven architecture introduces a group of processes which have models as their pivot. Throughout such processes we have to deal with models and model transformations. Model-driven architecture presents different abstraction levels for models used in a process. Model-driven architecture which, starting from business models acquired from the environment sets out guidelines for obtaining models that produces software source code as its final goal. The most important issue in model-driven architecture is transformation between models of different abstraction levels. Among them... 

Design patterns as successful solutions of recurring problems, have attracted much attention in the field of Software Engineering. These Patterns, which are derived from the principles of Object-Oriented programming, are fine-grained architectures that have significant impact on software quality attributes such as maintainability, scalability, configurability, understandability, and so on. On the other hand, Refactoring as behavior protective method for making changes to software structure, to enhance maintainability and reduce the cost of changes, is now widely used in industry. This structural changes, can be as simple as moving a method or adding a parameter, or as complex as transforming... 

Software Reuse, the use of (pre)existing artifacts to create new systems, can reduce development costs and improve software quality and productivity. With a primary investment, Software Product Line facilitates a systematic reuse of the common parts of an specific domain in developing similar systems of that domain. On the Contrary, Agile Methods who value working software over comprehensive documentations and such investments is not done, lack reuse in developing similar systems. Here the question arises: why do we completely or almost miss such reuse when the only focus is on creating working software? When such investments or additional works like documentation are not done? Is there any... 

Generating test cases based on software input interface is a black-box testing technique that can be made more effective by using structured input models such as input grammars. Automatically generating grammar-based test inputs may lead to structurally valid but semantically invalid inputs that may be rejected in early semantic error checking phases of a system under test. This research aims to introduce a method for specifying a grammar-based input model with the model’s semantic constraints to be used in the generation of positive test inputs. It is also important that the method can generate effective test suites based on appropriate grammar-based coverage criteria. Formal specification... 

Application of evolutionary algorithms in software testing, called evolutionary testing, has been an area of interest for many researchers. Automatic generation of test cases is the main purpose of evolutionary testing. In recent years lots of tools for test case generation in structured and object oriented softwares has been developed using different evolutionary algorithms. All of theses tools targeted unit test case generation and high code coverage of class under test. In this thesis we propose an approach for generation of integration test cases in object oriented softwares. We use bottom-up integration approach for generation of test cases by applying the solutions presented for... 

There are different classes of event-driven softwares. These softwares include Graphical user interface, web application or embedded software. In these kinds of softwares, each user’s action while using application, is known as “event”. The application responds to the action through changing behavior and then waiting for another event. Testing software is the best way for checking the quality assurance of event-driven softwares. However, there are some problems, such as lengthy event sequences, in testing these kinds of softwares. Therefore, many solutions are introduced for these problems. The goal of this report, is presenting new testing procedure for event-driven Android applications....