Sharif Digital Repository

An adjustable join (AdjoinAdjoin) scheme [4] is a symmetric-key primitive that enables a user to securely outsource his database to a server, and later to issue join queries for a pair of columns. When queries are extended to a list of columns, the 3Partition3Partition security of Adjoin schemes [8] does not capture the expected security. To address this deficiency, we introduce the syntax and security notion of multi-adjustable join (M-AdjoinM-Adjoin) schemes. We propose a new security notion for this purpose, which we refer to as M3PartitionM3Partition. The 3Partition3Partition security of AdjoinAdjoin extends to the M3PartitionM3Partition security of M-AdjoinM-Adjoin in a straightforward... 

Database management systems (DBMS) are one of cloud services with major applications in industry and business. In the use of such services, since the cloud service provider cannot be entrusted with the plain data, the databases are typically encrypted prior to outsourcing. One of the most challenging issues in designing these services is supporting SQL join queries on the encrypted database. The multi-adjustable join scheme (M-Adjoin) [Khazaei-Rafiee 2020], an extension of Adjoin [Popa-Zeldovich 2012 and Mironov-Segev-Shahaf 2017], is a symmetric-key primitive that supports the join queries for a list of column labels on an encrypted database. In previous works, the following security... 

Database management systems (DBMS) are one of cloud services with major applications in industry and business. In the use of such services, since the cloud service provider cannot be entrusted with the plain data, the databases are typically encrypted prior to outsourcing. One of the most challenging issues in designing these services is supporting SQL join queries on the encrypted database. The multi-adjustable join scheme (M-Adjoin) [Khazaei-Rafiee 2020], an extension of Adjoin [Popa-Zeldovich 2012 and Mironov-Segev-Shahaf 2017], is a symmetric-key primitive that supports the join queries for a list of column labels on an encrypted database. In previous works, the following security... 

One of the organizations’ main concerns is to protect sensitive data in database systems, especially the ones outsourced to untrusted service providers. An effective solution for this issue is to employ database encryption methods. Among different encryption approaches, Bucket-based method has the advantage of balancing security and performance of database operations. However, generating false-positive results in executing queries is the main drawback of this method. On the other hand, multi-join queries are one of the most critical operations executed on these stored sensitive data. Hence, acceptable processing and response time in executing multi-join queries is required. In this paper, we... 

The increase in complexity and rate of technological changes in modern software development has led to a demand for systematic methods that raise the abstraction level for system maintenance and regression testing. Model-driven development (MDD) has promised to reduce extra coding efforts in software maintenance activities using traceable change management. The research described in this paper presents a Z-notation-based framework, called delta-based regression testing (DbRT), for formal modeling of regression testing in the context of MDD. The framework proposes to propagate the changes from a software specification to testing artifacts in order to preserve consistency after system... 

A major challenge organizations face when hosting or moving their data to the Cloud is how to support complex queries over outsourced data while preserving their confidentiality. In principle, encryption-based systems can support querying encrypted data, but their high complexity has severely limited their practical use. In this paper, we propose an efficient yet secure secret sharing-based approach for outsourcing relational data to honest-but-curious data servers. The problem with using secret sharing in a data outsourcing scenario is how to efficiently search within randomly generated shares. We present multiple partitioning methods that enable clients to efficiently search among shared... 

Fetching Lexico-Syntactic patterns from text rely on pairs of words (positive instances) that represent the target relation, and finding their simultaneous occurrence in text corpus. Due to existence of WordNet thesaurus (which contains the semantic relationship between words), collecting positive instances is easy. In non-english languages, it's hard to collect large number of positive instances in various contexts. We investigated some new ideas for collecting them in Persian language and finally run the best one and collected approximately 6,000 positive instances  

Modeling languages are needed to describe the conceptual construct underlying software. Several modeling languages have been proposed during the last decades. Cognitive complexity is one of the common problems in designing modeling languages. Users have to split their attention and cognitive resources between two different tasks when working with complex language: solving the problem and understanding the elements composing the language. Several researches have been accomplished to evaluate cognitive complexity of modeling languages, among them, metric based and empirical approaches aremore important and convenient than others. In this paper, we compared these two methods. Results show that... 

One of the most important services in the Semantic Web is the Reasoning Service. According to the Semantic Web requirements, reasoning under time pressure or other restrictions is needed; and, reasoning which is not 'perfect' but instead 'good enough' for given tasks is acceptable. One of the approaches for the improvement of reasoning performance is approximation; of course, there is an effort for raising more precise approximations. One of the fields in which approximation seems to be useful is query. So far, all of the approximation strategies introduced for conjunctive queries just consider the query's structure. In this paper, a semantic approach for conjunctive query approximation... 

Registration websites use CAPTCHA (Completely Automated Public Turing test to tell Computers and Human Apart) systems to prevent the bot programs from wasting their resources. But sometimes the CAPTCHA test is difficult for human users to pass because the users have different ages, languages, etc. In this paper we propose a solution for this problem. The registration system can select a kind of CAPTCHA system among different available CAPTCHA systems regarding to the user's needs such as user language and disabilities. For example if the user has non-English language, the system chooses a CAPTCHA method which does not need English language knowledge. © 2008 IEEE  

Reo is an exogenous coordination language for compositional construction of the coordinating subsystem of a component-based software. Constraint automaton is defined as the operational semantics of Reo. The main goal of this work is to prepare a model checking based verification environment for component-based systems, which their component connectors are modeled by Reo networks and Constraint Automata. We use compositional minimization and abstraction methods of model checking for verification of component-based systems and their component connectors modeled by Reo  

In the last two decades, a number of architecture-based software development notations, methods, techniques, and tools were formulated. Of particular interest to the software architecture researchers and practitioners were the notations and languages for modeling software architectures, known as ADLs. Object Stochastic Activity Network (OSAN) is a new model which inherits useful features from Petri nets, stochastic activity networks and queue networks, which made it a powerful and flexible tool to model concurrent systems and evaluate and verify them. This paper introduces OSAN as a new analyzable architecture description language, which can be used both for modeling architectural aspects of... 

Recently query log mining is extensively used by web information systems. In this paper a new hierarchical co-clustering for queries and URLs of a search engine log is introduced. In this method, firstly we construct a bipartite graph for queries and visited URLs, and then to discover noiseless clusters, all queries and related URLs are projected in a reduced dimensional space by applying singular value decomposition. Finally, all queries and URLs are iteratively clustered for constructing hierarchical categorization. The method has been evaluated using a real world data set and shows promising results. © Springer-Verlag Berlin Heidelberg 2007  

Modern search engines use link structure of the World Wide Web in order to gain better results for ranking the results of users' queries. One of the most popular ranking algorithms which is based on link analysis is HITS. It generates very accurate outputs but because of huge amount of online computations, this algorithm is relatively slow. In this paper we introduce PHITS, a parallelized version of the HITS algorithm that is suitable for working with huge web graphs in a reasonable time. For implementing this algorithm, we use WebGraph framework and we focus on parallelizing access to web graph as the main bottleneck in the HITS algorithm. © 2006 IEEE  

In this paper, we consider the problem of computing the visibility of a query point inside polygons with holes. The goal is to perform this computation efficiently per query with more cost in the preprocessing phase. Our algorithm is based on solutions in [13] and [2] proposed for simple polygons. In our solution, the preprocessing is done in time O(n3 log(n)) to construct a data structure of size O(n3). It is then possible to report the visibility polygon of any query point q in time O((1 + h′) log n + |V(q)|), in which n and h are the number of the vertices and holes of the polygon respectively, |V(q)| is the size of the visibility polygon of q, and h′ is an output and preprocessing... 

This paper presents UOWD-Sharif team's approach for XML information retrieval. This approach is an extension of PLIR which is an experimental knowledge-based information retrieval system. This system like PLIR utilizes plausible inferences to first infer the relevance of sentences in XML documents and then propagates the relevance to the other textual units in the document tree. Two approaches have been used for propagation of confidence. The first approach labeled "propagate-DS" first propagates the confidence from sentences to upper elements and then combines these evidences by applying Dempster-Shafer theory of evidence to estimate the confidence in that element. The second approach... 

Different structures are used in peer-to-peer networks to represent their inherently distributed, self-organized, and decentralized memory structure. In this paper, a simple range-queriable distributed data structure, called RAQ, is proposed to efficiently support exact match and range queries over multi-dimensional data. In RAQ, the key space is partitioned among the network with n nodes, in which each element has links to O(log n) other elements. We will show that the look-up query for a specified key can be done via O(log n) message passing. Also, RAQ handles range-queries in at most O(logn) communication steps. © Springer-Verlag Berlin Heidelberg 2005  

XML has become the preferred format for representing and exchanging structured and semi-structured data on the web. The XML Schema language is widely used for defining and validating highly structured XML instance documents. While text-based languages, such as XML-Schema, offer great advantages for data interchange on the Internet, graphical modeling languages are widely accepted as a more visually effective means of specifying and communicating data requirements for a human audience. This paper uses Object-Relationship-Attribute model (ORA-SS) as a conceptual graphical model for designing XML-Schemas. To facilitate this process we introduce an xml representation for ORA-SS Schema Diagram... 

Class-based n-gram language models are those most frequently-used in continuous speech recognition systems, especially for languages for which no richly annotated corpora are available. Various word clustering algorithms have been proposed to build such class-based models. In this work, we discuss the superiority of soft approaches to class construction, whereby each word can be assigned to more than one class. We also propose a new method for possibilistic word clustering. The possibilistic C-mean algorithm is used as our clustering method. Various parameters of this algorithm are investigated; e.g., centroid initialization, distance measure, and words' feature vector. In the experiments...