Sharif Digital Repository

Textual news published in the media on a daily basis is a large and valuable source of unstructured data that can be used to analyze and model the financial market by using text mining methods. The purpose of this study is to design a news-reading system for economic analysis and modeling of gold prices using features extracted from textual news and text mining methods; it seeks to enable the machine to read news like financial analysts then analyze and forecast the economic situation and market trends. For this purpose, we collected news from the website of an Iranian economic news agency. To design the economic analyzer, we extracted important economic, political, and social factors from... 

Three distinct areas in linguistic studies are typically considered, namely, syntax, semantics and pragmatics. Each category has a specific realm and deals with special linguistic phenomena. Presenting exact definition and clarification of the corresponding boundaries of each area is considered in both linguistics and philosophy of language. In order to explain the “meaning” for sentences of a language, this issue turns out to be vital. Representing the definition and evaluating the domain of each area, is the objective of the first chapter. In chapter two, some important semantic theories have been investigated. Since at first one semantic theory ought to clear its position about reference,... 

Common Object Request Broker Architecture (CORBA) is a standard for hybrid applications that is designed and supported by Object Management Group (OMG). This standard defines protocols and Relational Data Model Objects / Services which can be connected into heterogeneous software (written in different languages). So we can use CORBA to share the distributed object platform, without worrying about where they are located or who has designed them. CORBA can package the codes (in some programming languages) and add the packaging information, such as the ability to execute the codes and how to implement them. So this package or object code can execute some other programs or CORBA objects that... 

The purpose of this dissertation is proposing a probabilistic model in transition systems of records. In these systems, two acceptance state of finite and infinite string have proposed which acceptance state of finite string is called probabilistic finite automata of records and acceptance state of infinite string is called probabilistic buchi automata of records. The buchi automata of records is an operational semantic for Reo coordination language. Reo is a coordination language to coordinate existing component of a component based system. Reo circuits with non-deterministic and probabilistic channel can be modeled by proposing probabilistic buchi automata of records. In this dissertation... 

The main goal of this thesis is to verify real-time properties of timed coordinated systems specified by timed-Reo circuits using the model checking techniqe. We use Timed Buchi Automata of Records (TBAR) as the semantics of timed-Reo. The model checking is done by converting Timed Buchi Automata of Records to an extension of Timed Automata that are usingas input of UPPAAL tool. We introduce a writer-automaton, which is synchronous with the desired Timed Automata, for initializing input ports. A tool that transforms Timed Buchi Automata of Records to UPPAAL Timed Automata has been implemented. Finally, two model checking case studies are examined by usingof our implemented tool over UPPAAL  

In this thesis the usage of probabilistic reasoning in collaborative filtering is investigated. The problem of predicting users' rating is formulated as a Bayesian decision problem and a generative probabilistic model is used in order to find the optimal decision. Two different probabilistic models are considered: user based model and rating based model. In user based model prediction of ratings is based on structural learning of Bayesian networks. In rating based model, we assume a predefined Bayesian network represents the joint distribution over model variables and rating prediction is carried out using McMc inference method. MovieLens dataset is chosen to evaluate and compare the results... 

Approximate Agreement (AA) is one of the most important issues in distributed networks in which non-faulty processes execute a voting algorithm to reach the values that are very close to each other. AA for Partially Connected Networks (PCNs) is very limited because a node may not have a complete view of the whole network which makes it difficult to reach the convergence. This research proposes a convergent Fuzzy algorithm for synchronous distributed networks in the presence of faulty or Byzantine processes. When each node receives a new value from its neighbors,it runs the convergent Fuzzy algorithm. If the received value is not in the expected range of values, the processor can discard the... 

In a distributed system, each solution for the problem of Byzantine Agreement requires that some of correct processes reach a common decision value from a set of proposed values while Byzantine processes may behave arbitrary. This problem is one of the most fundamental problems in the theory of distributed systems. While the problem has been widely studied in fully-connected fixed networks, few studies have been carried out in the context of self-organizing mobile networks such as Mobile Ad-Hoc Networks.
This research presents a randomized consensus protocol with three additional modules for the case of dynamic networks: Participant Detectors, Failure Detectors and Maintainer. We assume... 

Network Motifs are subgraphs that appear more frequently in real networks than randomize networks. Frequent replication of a subgraph could imply evolution, network performance or some other particular reasons. From algorithmic perspective, network motif discovery in a graph is a difficult problem. Since, at least it includes the whole graph isomorphism. Hence, for solving this problem in practice, we need computable graphs. The existing algorithms so far, have high running times and memory usages. In this thesis, we present a new algorithm called CGQ. Within this algorithm, we use both QuateXelero and G-Trie algorithms which respectively have better performance in census of real networks... 

Monitoring of activities of elderly and intelligent decisions about their living environment is a key challenge in smart environments. In the case of such challenges, correctness of system performance is highly dependent on how the model is designed. In the ambient intelligence (AMI) modeling, formal modeling is one of the best approaches because it supports certainty. In addition, time, location and mobility in AMI are crucial requirements, particularly in emergency treatment services. Ambient calculus is a formalism for describing mobility, process migration and message transfer, but it cannot express metric time duration. In this paper we propose an extension of ambient calculus with time... 

Security protocols assure the security of the communications in computer systems using techniques such as cryptographic primitives. However, the usage of such protocols is faced by the lack of fault tolerance, where a minor disruption could cause a destructive damage. Therefore, there is a requirement to assess the reliability of these protocols. In this thesis model checking of timed security protocols is done. Model checking process includes steps that will be modeling protocol with high level and human readable specification language named THLPSL and converting this specification to special kind of timed automata named XTA and model checking will be done with UPPAAL verification tool. We... 

Paraphrases are sentences or phrases, which convey the same meaning using different words. There are different definitions for paraphrasing and most linguists believe that, paraphrases approximately equivalent in meaning. Paraphrase recognition is useful in different natural language processing areas such as question answering, information extraction, plagiarism recognition and machine translation. In this thesis, the purpose is to present a method for paraphrase recognition, using deep semantic analysis and meaning representation of sentences. To achieve this purpose first, meaning features were defined for every syntactic category and semantic analysis of sentences alongside mapping of... 

With long-term evolution of large scale software systems, the study and engineering of architectural evolution becomes more and more important. In order to manage high level changes, the architects should plan the architecture evolution in a series of releases. Planning and analysis of architectural evolution is a challenge and plays a significant role in evolution management. An assessment solution could promote overall accuracy and quality of the evolution process. Compliance checking with expert-defined rules is a well-known assessment solution and could be applied in the field of architectural evolution. In this thesis, a solution is proposed in order to compliance check these evolution... 

If we consider a point set on the plane as the vertices and straight-line segments between them as the edges of a graph, and weight of each edge is equal to its Euclidean length, from this kind of graphs, triangulation is the graph with maximum number of the edges. In a triangulation, dilation of any two vertices is equal to the ratio of their shortest path length to their Euclidean distance, and dilation of the triangulation is defined as the maximum dilation of any pair of its vertices. Dilation is a characteristic that shows how much a triangulation approximates a complete graph. In the minimum dilation triangulation problem, the objective is to find a triangulation of a given set of... 

The amount of ever-growing generated data increases the need for automatic methods in text processing. As a solution, sentence compression and text summarization are considered as methods of managing and dealing with this huge amount of data. Additionally, Sentence compression is also useful in different text processing systems such as text summarization, news condensation, information extraction and question-answering systems. A sentence compression system takes a long sentence as input and returns a shorter form of the sentence in a way that its important information and grammaticality is preserved. In this thesis, we devise a rule-based extractive sentence compression method. This... 

Knowledge graphs are structured data sources which are widely used in the information process techniques. There are general and specialized knowledge graphs out there. These graphs will be used as the kernel of future search engines. Due to the lack of proper and tested Persian knowledge graphs, a method for knowledge graph extraction from news sources of the web has been introduced in this research.A knowledge graph extraction system from the unstructured web sources has been implemented in this research. In order to achieve this, a training dataset for the classifier was first extracted from semi-structured data of Wikipedia pages. At that time sentences were extracted from the... 

In recent years, cloud computing has provided a well-known platform to provide on-the-fly and cost-efficient services on local and world area networks. As a result, the number of cloud data centers is increasing due to the increasing number of customers. For this reason, the energy consumption of numerous cloud data centers is one of the biggest bottlenecks for cloud providers. In general, various hardware and software-based solutions can be used to optimize power consumption at the same time of guaranty service level agreements. One of the most popular of these software-based solutions is dynamic allocation of resources to virtual machines (VM), i.e. a sandboxing technique responsible for... 

Developing distributed systems is always harder than centralized systems, because in distributed systems there are problems like how nodes must collaborate with each other, throughput, latency and so on, that is not concerned in centralized systems. For solving this problem, It's better to have an abstract view of system to show this concerns. one of the coordination languages to have that abstract view of system, is Reo language. Reo language is a coordination language that describe how components of systems, can coordinate with each other. This project is built to decrease the distance between designing and implementing. In this project an abstract view of system which is in Reo language,... 

In component-based design, each system consists of a set of heterogeneous components that are in interaction with each other. In this approach of design, computation is executed by the components, and their interactions are considered individually. BIP and Reo are coordination languages implemented in component-based modeling of systems. The BIP framework has a layered structure to separate interactions from the calculations. There are several approachesfor the formal definition of BIP layers. There are also semantics for BIP, based on two data-based and data-agnostic approaches. On the other hand, automata of records of a model is an operational semantics for Reo coordination language, one... 

The progress and development in the field of Natural Language Processing (NLP) have led to the emergence of Natural Language Understanding (NLU). One of the main objectives in this field is inference, deduction, or entailment from the phrases (sentences) of a natural language. The crucial question here is whether it is possible to semantically infer a natural language hypothesis from a set of natural language premises. Since in many applications of Natural Language Inference (NLI) in the real world, it has a decisive role, this problem is of the utmost importance. Furthermore, the previously proposed approaches to tackle this problem incorporate a wide range of classic logic-based and new...