Mostafa Salehi

University of Tehran | UT

Textual contents are very powerful sources of information about events. Twitter, as a microblogging social network provides such a platform for users in order to publish their thoughts about a special happening. However, deliberation on this social network indicates that words are majorly used in sentiments different that their original sounds. For...

The diffusion process in networks is studied with the objective of identifying the dynamics and for predicting the behavior of network entities. Social media plays an important role in people's lives. Diffusion processes, as one of the most important branches of social media analysis, have their presence in various domains such as information sprea...

برمبنای مفاهیم علوم داده و شبکه، هر سیستم اطلاعاتی در دنیای واقعی را می¬توان به شکل یک شبکه اطلاعاتی شامل عامل‌ها و ارتباط‌های مابین آنها مدلسازی کرد، که از آن جمله می‌توان به شبکه‌های اجتماعی، کامپیوتری، زیستی و اقتصادی اشاره کرد. تشخیص رفتارهای ناهنجار در شبکه¬های اطلاعاتی، کاربردهای مختلفی را متناسب با حوزه مورد مطالعه شامل می‌شود و از اهمیت ویژ...

Identifying influential users and measure the influence of nodes in social networks have become an interesting and important topic of research. It is crucial to find out to what extent individuals influence each other because it can be used to control rumors, diseases, and diffusion. There are numerous relevant models most of which are based on a h...

Crowdsourcing has been widely used recently as an alternative to traditional annotations that is costly and usually done by experts. However, crowdsourcing tasks are not interesting by themselves, therefore, combining tasks with game will increase both participants motivation and engagement. In this paper, we have proposed a gamified crowdsourcing...

In recent years, with the growing number of online social networks, these networks have become one of the best markets for advertising and commerce, so studying these networks is very important. Forecasting new edges in online social networks can give us a better understanding of the growth of these networks. There have been many studies of link pr...

With the social media engagement on the rise, the resulting data can be used as a rich resource for analyzing and understanding different phenomena around us. A sentiment analysis system employs these data to find the attitude of social media users towards certain entities in a given document. In this paper we propose a sentiment analysis method fo...

In addition to formal and informal words, Contemporary Persian also consists of some words which due to Phonetic changes have different written form from both their formal and informal equivalents. These variations are not fixed and usually produce words which are not having unified forms. So these out-of-vocabulary units cannot be analyzed with a...

Complex networks have now become integral parts of modern information infrastructures. This paper proposes a user-centric method for detecting anomalies in heterogeneous information networks, in which nodes and/or edges might be from different types. In the proposed anomaly detection method, users interact directly with the system and anomalous ent...

Some networked systems can be better modeled by multilayer structure where the individual nodes develop relationships in multiple layers. Multilayer networks with similar nodes across layers are also known as multiplex networks. This manuscript proposes a novel framework for predicting forthcoming or missing links in multiplex networks. The link pr...

Some networked systems can be better modelled by multilayer structure where the individual nodes develop relationships in multiple layers. Multilayer networks with similar nodes across layers are also known as multiplex networks. This manuscript proposes a novel framework for predicting forthcoming or missing links in multiplex networks. The link p...

Seasonal influenza epidemics affect millions of people with respiratory illnesses and cause 250,000 to 500,000 deaths worldwide each year. Rapidly predicting the outbreak of epidemics leads to an earlier detection and control. In this study, we predicted an influenza-like illness (ILI) based on social media data derived from Twitter. Tweets and pat...

با فراگیر شدن اینترنت و وب حجم زیادی از متون که به هر زبانی نوشته می‌شوند در دسترس است. مسئله تشخیص زبان یکی از مراحل اصلی برای هر نوع پردازش دیگر بر روی متن است. تاکنون پژوهش‌هایی بر روی تشخیص زبان در متون انگلیسی انجام شده اما کارها روی زبان فارسی در این حوزه محدود است. از طرفی با گسترش رسانه‌های اجتماعی متون محاوره بیشتر مورد استفاده قرار می‌گیر...

Opportunistic networks are delay-tolerant networks which enable network connectivity while there is limited access to network infrastructure, such as natural disaster happenings. Since opportunistic networks use store-carry-forward mechanism to deliver data, routing algorithms have significant impact on successful data delivery. Due to the Operatin...

Opportunistic networks are delay-tolerant networks which enable network connectivity while access to network infrastructure is limited, such as natural disaster happening. Since opportunistic networks use store-carry-forward mechanism to deliver data, routing algorithms have significant impact on data delivery. Due to the Operating System restricti...

Complex networks have now become integral parts of modern information infrastructures. This paper proposes a user-centric method for detecting anomalies in heterogeneous information networks, in which nodes and/or edges might be from different types. In the proposed anomaly detection method, users interact directly with the system and anomalous ent...

Multiplex networks are defined by the presence of multiple edge types. As a consequence, it is hard to produce a single visualization of a network revealing both the structure of each edge type and their mutual relationships: multiple visualization strategies are possible, depending on how each edge type should influence the position of the nodes i...

Diffusion of information in complex networks largely depends on the network structure. Recent studies have mainly addressed information diffusion in homogeneous networks where there is only a single type of nodes and edges. However, some real-world networks consist of heterogeneous types of nodes and edges. In this manuscript, we model information...

Respondent Driven Sampling (RDS) is a popular network-based method for sampling from hidden population. This method is a type of chain referral (or snowball) sampling in which an estimator is used to infer the proportion of the population with that property. Existing RDS estimators are asymptotically unbiased based on various underlying assumptions...

Name Entity Recognition (NER) is one of the main components of information extraction systems. It identifies the name entities of a textual document into their categories such as names of persons, organizations and locations. The documents in microblog services or social media sites often include informal texts which processing them is challenging....

The shortest path problem is one of the most fundamental networks optimization problems. Nowadays, individuals interact in extraordinarily numerous ways through their offline and online life (e.g., co-authorship, co-workership, or retweet relation in Twitter). These interactions have two key features. First, they have a heterogeneous nature, and se...

Nowadays, a big part of people rely on available content in social media in their decisions (e.g. reviews and feedback on a topic or product). The possibility that anybody can leave a review provide a golden opportunity for spammers to write spam reviews about products and services for different interests. Identifying these spammers and the spam co...

Since full coverage treatment is not feasible due to limited resources, we need to utilize an immunization strategy to effectively distribute the available vaccines. On the other hand, the structure of contact network among people has a significant impact on epidemics of infectious diseases (such as SARS and influenza) in a population. Therefore, n...

We introduce multiforce, a force-directed layout for multiplex networks, where the nodes of the network are organized into multiple layers and both in-layer and inter-layer relationships among nodes are used to compute node coordinates. The proposed approach generalizes existing work, providing a range of intermediate layouts in-between the ones pr...

Several systems can be modeled as sets of interconnected networks or networks with multiple types of connections, here generally called multilayer networks. Spreading processes such as information propagation among users of online social networks, or the diffusion of pathogens among individuals through their contact network, are fundamental phenome...

The ways in which an innovation (e.g., new behaviour, idea, technology, product) diffuses among people can determine its success or failure. In this paper, we address the problem of diffusion of innovations over multiplex social networks where the neighbours of a person belong to one or multiple networks (or layers) such as friends, families, or co...

Several systems can be modeled as sets of interdependent networks where each network contains distinct nodes. Diffusion processes like the spreading of a disease or the propagation of information constitute fundamental phenomena occurring over such coupled networks. In this paper we propose a new concept of multidimensional epidemic threshold chara...

Since there is no difference between uplink and downlink subframes in the IEEE 802.16 mesh mode; both downlink and uplink traffics are transmitted within a single time frame. Hence, in most scheduling methods, only one scheduling algorithm is used for both uplink and downlink traffic. However, because of the different characteristics of uplink and...

Partially-observed data collected by sampling methods is often being studied to obtain the characteristics of information diffusion networks. However, these methods usually do not consider the behavior of diffusion process. In this paper, we propose a novel two-step (sampling/estimation) measurement framework by utilizing the diffusion process char...

Several systems can be modelled as sets of interdependent networks or networks with multiple types of connections, here generally called multilayer networks. Diffusion processes like the propagation of information or the spreading of diseases are fundamental phenomena occurring in these networks. However, while the study of diffusion processes in s...

How does one develop a new online community that is highly engaging to each user and promotes social interaction? A number of websites offer friend-finding features that help users bootstrap social networks on the website by copying links from an established network like Facebook or Twitter. This paper quantifies the extent to which such social boo...

Despite the efforts to design better antivirus soft-ware, malware continue to spread and cause enormous damages. Effect of immunizing computer systems as the most effective control policy for preventing such infections is two-fold. On one hand, it increases the global immunity of the network by providing indirect protection for unimmunized systems....

This paper presents a new Compressive Sensing (CS) scheme for detecting network congested links. We focus on decreasing the required number of measurements to detect all congested links in the required number of measurements to detect all congested links in the context of network tomography. We have expanded the LASSO objective function by adding a...

Partially-observed network data collected by link-tracing based sampling methods is often being studied to obtain the characteristics of a large complex network. However, little attention has been paid to sampling from directed networks such as WWW and Peer-to-Peer networks. In this paper, we propose a novel two-step (sampling/estimation) framework...

The current multi-channel P2P video streaming architectures still suffer from several performance problems such as low Quality of Service (QoS) in unpopular channels. The P2P systems are inherently dynamic, and their performance problems could be categorized into four groups, peer churn, channel churn, uncooperative peers, and geographical distribu...

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 Recons...

The diffusion phenomenon has a remarkable impact on Online Social Networks (OSNs). Gathering diffusion data over these large networks encounters many challenges which can be alleviated by adopting a suitable sampling approach. The contributions of this paper is twofold. First we study the sampling approaches over diffusion networks, and for the fir...

Recently, using Peer-to-Peer (P2P) overlay architectures have become a popular approach for live video streaming over the Internet. Since the peers in these systems are geographically distributed, the communication between them imposes huge redundant traffic into the Internet. One solution to address this problem is utilizing the locality aware alg...

The emerging multimedia applications of Wireless Sensor Network (WSNs) impose new challenges in design of algorithms and communication protocols for such networks. In the view of these challenges, error control is an important mechanism that enables us to provide robust multimedia communication and maintain Quality of Service (QoS). Despite the exi...

Using Peer-to-Peer (P2P) overlay networks have become a progressively popular approach for streaming live media over the Internet due to their deployment simplicity and scalability. In this paper, we propose a new hybrid push-pull live P2P video streaming protocol called PPM that combines the benefits of pull and push mechanisms for video delivery....

In this paper, we propose a novel link-tracing sampling algorithm, based on the concepts from PageRank vectors, to sample from networks with high community structures. Our method has two phases; (1) Sampling the closest nodes to the initial nodes by approximating personalized PageRank vectors and (2) Jumping to a new community by using PageRank vec...

The quality of service inWireless Multimedia Sensor Networks (WMSN) is related to packet loss rate. Recently different studies have been done on developing efficient protocols in the transport layer for controlling packet loss in WMSN. However, all of these protocols are independent of the characteristics of multimedia content. In this paper, a nov...

Twitter as one of the most important microblogging online social networks has attracted more than 200 million users in recent years. Although there have been several attempts on characterizing the Twitter by using incomplete sampled data, they have not been very successful to estimate the characteristics of the whole network. In this paper, we char...

The spread of information cascades over social networks forms the diffusion networks. The latent structure of diffusion networks makes the problem of extracting diffusion links difficult. As observing the sources of information is not usually possible, the only available prior knowledge is the infection times of individuals. We confront these chall...

Networks of dynamical nodes serve as generic models for real-world systems in many branches of science ranging from mathematics to physics, technology, sociology and biology. Collective behavior of agents interacting over complex networks is important in many applications. The cooperation between selfish individuals is one of the most interesting c...

In this paper we address the problem of modelling brain functional networks using Electroencephalography (EEG) data. The high density EEGs of fourteen healthy subjects are processed and the topology of their brain network is extracted by employing partial correlation analysis. As the networks are constructed, some measures such as average degree, g...