Sharif Digital Repository

A comparative world map of scientific misconduct reveals that countries with the most rapid growth in scientific publications also have the highest retraction rate. To avoid polluting the scientific record further, these nations must urgently commit to enforcing research integrity among their academic communities. © 2017 Springer Science+Business Media B.V  

A comparative world map of scientific misconduct reveals that countries with the most rapid growth in scientific publications also have the highest retraction rate. To avoid polluting the scientific record further, these nations must urgently commit to enforcing research integrity among their academic communities. © 2017, Springer Science+Business Media B.V  

The current study investigated the attitudes of 140 Iranian English language learners toward World Englishes. The participants were required to listen to recordings of the same natural speech from a series of speakers with five different accents. The results showed that the participants had a more positive attitude toward American and British English. On the other hand, African-American Vernacular English received the lowest level and Persian English and Australian English were in the middle of this scale. While American English was evaluated as the most socially attractive and African-American as the least socially attractive, British and African-American accents were evaluated as of the... 

The current study investigated the attitudes of 140 Iranian English language learners toward World Englishes. The participants were required to listen to recordings of the same natural speech from a series of speakers with five different accents. The results showed that the participants had a more positive attitude toward American and British English. On the other hand, African-American Vernacular English received the lowest level and Persian English and Australian English were in the middle of this scale. While American English was evaluated as the most socially attractive and African-American as the least socially attractive, British and African-American accents were evaluated as of the... 

Identifying the factors affecting profitability is important from the perspective of market players. One of the most important benchmarks of firm performance is accounting profit and effective factors analysis so that users of accounting information analyse the factors affecting profit, firm performance and various aspects of its performance and according to estimates Done, make your own decision on how to allocate resources. The main purpose of this study is to investigate the impact of some factors of competitiveness, entrepreneurship and business environment indicators on the profitability of the world’s top companies. For this purpose, 176 top companies in the world from 2013 to 2018... 

In real-world networks, nodes might have more than one type of relationship. Signed networks are an important class of such networks consisting of two types of relations: positive and negative. Recently, embedding signed networks has attracted increasing attention and is more challenging than classic networks since nodes are connected by paths with multi-types of links. Existing works capture the complex relationships by relying on social theories. However, this approach has major drawbacks, including the incompleteness/inaccurateness of such theories. Thus, we propose network transformation based embedding to address these shortcomings. The core idea is that rather than directly finding the... 

As web contents grow, the importance of search engines became more critical and at the same time user satisfaction decreased. Query recommendation is a new approach to improve search results in web. In this paper we represent a method to help search engine users in attaining required information. Such facility could be provided by offering some queries associated with queries submitted by users in order to direct them toward their target. At first, all previous query contained in a query log should be clustered, therefore, all queries that are semantically similar will be detected. Then all queries that are similar to user's queries are ranked according to a relevance criterion. The method... 

Many applications in wireless networks impose locally distributed traffic on the network. We consider the effect of traffic localization on throughput of large wireless networks in the scaling sense. We show that by careful exploitation of traffic localization, one can enhance the throughput of various schemes in wireless networks. Also, the important case of Small World traffic distribution in wireless networks is addressed. In this type of traffic, in addition to the local traffic, a non-negligible amount of global traffic should be handled by the network. It is shown that a non-negligible amount of network-wide traffic can be tolerated by network without any performance degradation in the... 

This article introduces the concept of latecomer systems integration capability (LSIC) as a construct for theory development in the area of emergence and competitiveness of producers of complex capital goods from developing economies. The study draws on three bodies of the literature to conceptualize LSIC and then presents an in-depth case study of the development of LSIC in a major Iranian firm engaged in producing electricity generation systems. Although an exploratory study, the findings suggest that, in this case, LSIC evolved in a fairly short period of time from simple low-cost project management skills to innovative capabilities, supported by some sophisticated engineering and design... 

Many real-world networks show community structure characterized by dense intra-community connections and sparse inter-community links. In this paper we investigated the synchronization properties of such networks. In this work we constructed such networks in a way that they consist of a number of communities with scale-free or small-world structure. Furthermore, with a probability, the intra-community connections are rewired to inter-community links. Two synchronizability measures were considered as the eigenratio of the Laplacian matrix and the phase order parameter obtained for coupled nonidentical Kuramoto oscillators. We found a power-law relation between the eigenratio and the... 

Using mixed method research the current study has analyzed Iranian researchers' information searching behavior on the Web. Based on extracted concepts, the model of their information searching behavior was revealed. Forty-four participants, including academic staff from universities and research centers were recruited for this study selected by purposive sampling. Data were gathered from questionnaires including ten questions and semi-structured interview. Each participant's memos were analyzed using grounded theory methods adapted from Strauss & Corbin (1998). Results showed that the main objectives of subjects were doing a research, writing a paper, studying, doing assignments, downloading... 

By the immense growth of the Web-Based Social Networks (WBSNs), the role of trust in connecting people together through WBSNs is getting more important than ever. In other words, since the probability of malicious behavior in WBSNs is increasing, it is necessary to evaluate the reliability of a person before trying to communicate with. Hence, it is desirable to find out how much a person should trust another one in a network. The approach to answer this question is usually called trust inference. In this paper, we propose a new trust inference algorithm (Called RN-Trust) based on the resistive networks concept. The algorithm, in addition to being simple, resolves some problems of previously... 

So far several methods have been proposed for clustering the web. On the other hand, many algorithms have been developed for clustering the relational data, but their usage for the Web is to be investigated. One main category of such algorithms is density based methods providing high quality results. In this paper first, a new density based algorithm is introduced and then it is compared with other algorithms of this category. The proposed algorithm has some interesting properties and capabilities such as hierarchical clustering and sampling, making it suitable for clustering the web data. © Springer-Verlag Berlin Heidelberg 2007  

In [20] Krajíček and Pudlák discovered connections between problems in computational complexity and the lengths of first-order proofs of finite consistency statements. Later Pudlák [25] studied more statements that connect provability with computational complexity and conjectured that they are true. All these conjectures are at least as strong as [23-25].One of the problems concerning these conjectures is to find out how tightly they are connected with statements about computational complexity classes. Results of this kind had been proved in [20, 22].In this paper, we generalize and strengthen these results. Another question that we address concerns the dependence between these conjectures.... 

In this paper we investigated the structural properties of the ultra high voltage power transmission network of Iran. We modeled the power grid as a network with 105 nodes and 142 connection links. We found that the Iranian power grid displays a relatively moderate clustering coefficient-much larger than that of corresponding random networks-and small characteristics path length comparable to that of corresponding random networks; i.e. the power grid is a small-world network with exponential degree distribution. Global efficiency was considered as an indicator of grid's performance and the influence of random and intentional nodal failures on the efficiency was investigated. We also studied... 

Many real-world systems and applications such as World Wide Web, and social interactions can be modeled as networks of interacting nodes. However, in many cases, one encounters the situation where the pattern of the node-to-node interactions (i.e., edges) or the structure of a network is unknown. We address this issue by studying the Network Reconstruction Problem: Given a network with missing edges, how is it possible to uncover the network structure based on certain observable quantities extracted from partial measurements? We propose a novel framework called CS-NetRec based on a newly emerged paradigm in sparse signal recovery called Compressive Sensing (CS). The results demonstrate that... 

Many real-world networks have a modular structure, and their component may undergo random errors and/or intentional attacks. More devastating situations may happen if the network components have a limited load capacity; the errors and attacks may lead to a cascading component removal process, and consequently, the network may lose its desired performance. In this brief, we investigate the tolerance of cascading errors and attacks in modular small-world networks. This brief studies the size of the largest connected component of the networks when cascading errors or attacks occur. The robustness of the network is tested as a function of both the intermodular connection and intramodular... 

Many software development methodologies are based on modeling the real world. In some of these methodologies, real-world models are gradually transformed into software models, while in others, the real world is only considered as a preliminary source of insight into the physical business domain. Real-world modeling was pushed to the sidelines due to anomalies in real-world modeling approaches; however, with the advent of the Model-Driven Architecture (MDA), real-world conceptual modeling is likely to regain its importance. We propose a method for using Design Patterns in the context of model transformation, where real-world models are refactored through application of these patterns....