Sharif Digital Repository

The quality of service in Wireless Multimedia Sensor Networks (WMSN) is related to congestion in network. 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 novel transport layer protocol, called Energy Efficient Congestion Avoidance (EECA), is proposed to minimize the packet loss ratio in WMSN by predicting congestion in network, and adjusting the source nodes output rate before congestion happening. EECA adjusts the output video quality in source nodes to adjust the source nodes video quality. The... 

This paper presents a comparative performance analysis in more realistic scenario and more performance metrics of ADMR and ODMRP, two on-demand multicast routing protocols for Mobile Ad hoc Networks (MANETs) and Wireless Sensor Networks (WSNs). There are a few comparison works done between two multicast Ad hoc routing protocols, ADMR and ODMRP; these works are not complete in terms of both performance metrics and realistic scenarios. Simulation results show an unusual low number of control packets transmitted per data packet delivered in ADMR, this low number of control packet transmitted per data packet in ADMR has caused some comparison works to judge to better performance of ADMR than... 

Nowadays, we are facing epidemic spreading in many different areas; examples are infection propagation, rumor spreading and computer viruses in computer networks. Finding a strategy to control and mitigate the spread of these epidemics is gaining much interest in recent researches. Due to limitation of immunization resources, it is important to establish a strategy for selecting nodes which has the most effect in mitigating epidemics. In this paper, we propose a new algorithm that minimizes the worst expected growth of an epidemic by reducing the size of the largest connected component of the underlying contact network. The proposed algorithm is applicable to any level of available resources... 

In this paper, we present a new approach to localize a bug in the software source file hierarchy. The proposed approach uses log files of the revision control system and bug reports information in open bug repository of open source projects to train a Support Vector Machine (SVM) classifier. Our approach employs textual information in summary and description of bugs reported to the bug repository, in order to form machine learning features. The class labels are revision paths of fixed issues, as recorded in the log file of the revision control system. Given an unseen bug instance, the trained classifier can predict which part of the software source file hierarchy (revision path) is more... 

In this paper, we propose a new algorithm that minimizes the worst expected growth of an epidemic by reducing the size of the largest connected component (LCC) of the underlying contact network. The proposed algorithm is applicable to any level of available resources and, despite the greedy approaches of most immunization strategies, selects nodes simultaneously. In each iteration, the proposed method partitions the LCC into two groups. These are the best candidates for communities in that component, and the available resources are sufficient to separate them. Using Laplacian spectral partitioning, the proposed method performs community detection inference with a time complexity that rivals... 

Research in modeling epidemic spreading in static networks has reached maturity in recent years. On the contrary, disease spreading in dynamic networks can be considered as an important open issue. Hence, mapping dynamic interactions of crowds to a static network and then immunizing the resulting network is the subject of this paper. In this work, we analogize spreading of diseases in dynamic networks -based on dynamic interactions- to message delivery in opportunistic networks. Thus, different diseases which have different spreading behaviors could be simulated by specific routing protocols. Having used interactions among individuals in the utilized dataset, the resulting network is... 

Nowadays, deployment of peer-to-peer video streaming systems over wireless mesh networks has attained raising popularity among large number of users around the world. In this paper, we present an efficient peer-to-peer live video streaming architecture over multi-hop wireless mesh networks. In our proposed architecture, we take the physical topology of network into account and based on a distributed distributed locality-aware neighbor selection algorithm in the overlay construction phase, we generate an efficient mesh-based overlay on top of wireless mesh networks. In locality-aware neighbor selection algorithm, instead of choosing randomly, peers find their best neighbors based on their... 

Multiple paths are mainly used in order to achieve higher throughput and reduce the end-to-end delivery latency as well. However, the overall network performance greatly suffers from the available interference between paths, even if node disjoint multipaths are used. This problem is highlighted more when dealing with transmission of the video data where the timeliness is of primary concern. In this paper, we propose a novel Interference-Aware Multipath routing for Video Delivery (IAMVD) in the realm of wireless multimedia sensor networks. It constructs multiple paths while considering the effect of different QoS requirements of multi-priority packets, without needing any hardware support for... 

The main source of energy consumption in the current MAC protocols for wireless sensor networks is idle listening. To mitigate this problem, duty cycling is used. However, it increases data delivery latency. In this paper, we propose an Interference-aware duty-cycle MAC (IMAC) protocol for wireless sensor networks that uses cross-layer information to reserve multiple paths for each source and send data packets along them efficiently. IMAC also handles the existing interference between these paths such that data packets can be delivered in the minimum required number of cycles. Simulation results in ns-2 show that the proposed algorithm has an average reduction of 49% in data delivery latency... 

This paper presents a mesh-pull peer-to-peer (P2P) live video streaming system. The proposed XOR-based Network Coding (XOR-NC) system is based on GIA protocol and introduces new search and answer data formats for chunks which are used by the network coding algorithm for exchanging data among peers. The search message contains the XORed GOP (Group of Picture) keys and some meta-data such as search key. The answer message, however, has the XORed GOP data and a summary of video blocks of the encoded GOP. In order to reduce the encoding complexity at each peer, a new content-based cache (CCache) is also introduced. Comparison of LiveCod with traditional GIA and GIA with random network coding... 

Recently it has been shown that network coding can highly improve the network throughput in the communication systems and specifically increase the downloading performance in P2P networks. This paper presents a new live streaming system for GIA-based P2P networks. In the proposed system the traditional GIA protocol is improved for an efficient use in multimedia applications. We introduce a new mesh-pull layered video streaming framework for GIA-based systems and employ random network coding to improve the network performance. Random network coding algorithm enables each peer to send a single encoded video chunk instead of multiple video blocks toward the destination node and save its... 

Error control is an important mechanism for providing robust multimedia communication in wireless sensor networks. Although there have been several research works in analysis of error control mechanisms in wireless multimedia networks and wireless sensor networks, but none of them are directly applicable to the wireless multimedia sensor networks (WMSNs) which has resource and performance constraints of WSNs as well as QoS requirements of multimedia communications. In this paper, we comprehensively evaluate the performance of several error control mechanisms in WMSNs. The results of our analysis provide an extensive comparison between automatic repeat request (ARQ), forward error correction... 

In this paper, we propose a new peer-to-peer (P2P) video streaming protocol which presents an implementation of network coding with a new caching mechanism. It employs a push-pull mechanism for sending the video chunks between peers. More specifically, this push-pull mechanism gives priority to the video chunks according to their video layers. The video base layer is transmitted through a pushing mechanism while the enhancement layers employ a pulling mechanism. Moreover, in the network coding algorithm of this protocol, we introduce a caching mechanism to improve the network's performance as well as the video streaming quality. The comprehensive simulations show that the proposed protocol... 

In this paper a new method for face virtual pose generation is presented. The proposed method uses subspace image representation. The general problem of blurring is addressed by introducing a multi resolution time-frequency analysis to subspace image representation. The training gallery contains face images in two different poses. Undecimated Wavelet Transform is applied on all training face images in first pose and the corresponding images in the second pose to produce image subbands. Then, a new subspace is constructed for each subband in both poses. The mapping between two corresponding subbands of two poses is learnt using linear regression. The resulted mapping matrix is used to... 

The growing interest in applications of Wireless Multimedia Sensor Networks (WMSNs) imposes new challenges on congestion control protocols in such networks. In this paper, we propose a new content-aware cross layer WMSN Congestion Control Protocol (WCCP) by considering the characteristics of multimedia content. WCCP employs a Source Congestion Avoidance Protocol (SCAP) in the source nodes, and a Receiver Congestion Control Protocol (RCCP) in the intermediate nodes. SCAP uses Group of Picture (GOP) size prediction to detect congestion in the network, and avoids congestion by adjusting the sending rate of source nodes and distribution of the departing packets from the source nodes. In... 

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. Our main goal is to minimize the network end-to-end delay compared to the pure mesh networks. The PPM consists of two phases; Pull-based and Push-based. In the first phase, a new peer joins to the network based on a pull-based mechanism. In the second phase, a parent node based on the peers' overlay hop count in the mesh topology is selected.... 

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 existence of some good research works on error control analysis in WSNs, none of them provides a thorough study of error control schemes for multimedia delivery. In this paper, a comprehensive performance evaluation of Automatic Repeat Request (ARQ), Forward Error Correction (FEC), Erasure Coding (EC), link-layer hybrid FEC/ARQ, and cross-layer hybrid... 

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 novel transport layer protocol, called User Datagram Dispatcher Protocol (UDDP), is proposed to minimize the packet loss ratio in WMSN by considering traffic characteristics, the inter-arrival pattern of packets and packet priority. UDDP is a new cross-layer transport layer that uses information of MAC and application layers to distribute packet... 

Peer-to-Peer overlay networks are an attractive foundation for video streaming. However, live Peer-to-Peer media streaming systems face many challenges such as bandwidth heterogeneity, node churn, and selfish nodes. Although many tree based and mesh based streaming protocols have been proposed, each has its own drawbacks such as unreliability and unfairness in tree based and long startup delay and complex scheduling in mesh based protocols. In this paper, we propose a new video streaming protocol called LayeredCast main features of which are: 1) Hybrid: Drawbacks of the simple approaches are compensated using a hybrid of mesh and tree overlays. 2) Layered Video: Provides an adaptive scheme... 

Catecholamine neurotransmitters, generally including dopamine (DA), epinephrine (EP) and norepinephrine (NE) are known as substantial indicators of various neurological diseases. Simultaneous detection of these compounds and their metabolites is highly recommended in early clinical diagnosis. To this aim, in the present contribution, a high performance colorimetric sensor array has been proposed for the detection and discrimination of catecholamines based on their reducing ability to deposit silver on the surface of gold nanorods (AuNRs). The amassed silver nanoshell led to a blue shift in the longitudinal localized surface plasmon resonance (LSPR) peak of AuNRs, creating a unique pattern...