Sharif Digital Repository

Modern societies are strongly dependent on the continuous and efficient operation of electric power systems as a critical infrastructure. Besides, information and communication systems play a crucial role in the resiliency enhancement of the power system. As power communication systems are vulnerable against physical and cyber attack, these systems themselves can be an internal source of threat for power grids. Therefore, there is a need to identify and study the threats and weaknesses of power communication systems using a comprehensive framework. This framework helps power communication network planners evaluate all challenges and their numerous effects on the system, as a very important... 

A potential peculiarity of software systems is that a large number of soft-errors are inherently derated (masked) at the software level. The rate of error-deration may depend on the type of algorithms and data structures used in the software. This paper investigates the effects of the underlying algorithms of programs on the rate of error-deration. Eight different benchmark programs were used in the study; each of them was implemented by four different algorithms, i.e. divide-and-conquer, dynamic, backtracking and branch-and-bound. About 10,000 errors were injected into each program in order to quantify and analyze the error-derating capabilities of different algorithm-designing- techniques.... 

Multiple description coding (MDC) is one of the promising solutions for live video delivery over lossy networks. In this paper, we present a review of MDC techniques based on their application domain and we explain their functionality, with the objective of giving enough insight to designers to decide which MDC scheme is best suited for their specific application based on requirements such as standard compatibility, redundancy tunability, complexity, and extendibility to n-description coding. The focus is mainly on video sources but imagebased algorithms applicable to video are considered as well. We also cover the well-known and important problem of drift and solutions to avoid it  

Abnormalities in the topology of brain networks may be an important feature and etiological factor for psychogenic non-epileptic seizures (PNES). To explore this possibility, we applied a graph theoretical approach to functional networks based on resting state EEGs from 13 PNES patients and 13 age- and gender-matched controls. The networks were extracted from Laplacian-transformed time-series by a cross-correlation method. PNES patients showed close to normal local and global connectivity and small-world structure, estimated with clustering coefficient, modularity, global efficiency, and small-worldness metrics, respectively. Yet the number of PNES attacks per month correlated with a... 

System Dynamics approach is a powerful tool in water resources systems simulation for evaluating proposed plans and policies in development projects. In Aras River basin, existing water resources do not suffice increasing demand in the near future, thus construction of new reservoirs is under study. In this study, system dynamics approach is used to simulate the water resources system of Darehrood sub basin located in eastern part of Aras River basin. Performance indices are used to evaluate the alternative plans and policies.. Reliability, resiliency and vulnerability, the three performance indices used in study, are estimated using maximum value and mean value estimators mentioned in the... 

Performance of routing is severely degraded when misbehaving nodes drop packets instead of properly forwarding them. In this paper, we propose a Game-Theoretic Adaptive Multipath Routing (GTAMR) protocol to detect and punish selfish or malicious nodes which try to drop information packets in routing phase and defend against collaborative attacks in which nodes try to disrupt communication or save their power. Our proposed algorithm outranks previous schemes because it is resilient against attacks in which more than one node coordinate their misbehavior and can be used in networks which wireless nodes use directional antennas. We then propose a game theoretic strategy, ERTFT, for nodes to... 

Network tools have been extensively applied to study the properties of brain functional and anatomical networks. In this paper, resiliency of Caenorhabditis elegans cortical networks against cascaded failures is studied. To this end, directed network formed by chemical connections and undirected network formed by electrical couplings through gap junctions are considered. Furthermore, two types of C. elegans networks are studied: the whole cortical network of the hermaphrodite type and the network of the posterior cortex in male C. elegans. The results show that resiliency of hermaphrodite and male networks is different. The male cortical network of chemical synapses shows extensively weaker... 

Locally multipath adaptive routing (LMAR) protocol, classified as a new reactive distance vector routing protocol for MANETs is proposed in this paper. LMAR can find an ad-hoc path without selfish nodes and wormholes using a random search algorithm in polynomial-time. Also when the primary path fails, it discovers an alternative safe path if network graph remains connected after eliminating selfish/malicious nodes. The main feature of LMAR to seek safe route free of selfish and malicious nodes in polynomial time is its searching algorithm and flooding stage that its generated traffic is equiloaded compared to single-path routing protocols but its ability to bypass the attacks is much better... 

Today, peer-to-peer networks are become more popular among internet users and more than millions peers share high volume of data from anywhere. Sending and receiving these data increase the network traffics terribly. By improving the performance of these networks not only the efficiency of these networks increase but also the overall performance of the internet augments. To achieve high performance and resilience to failures, a peer can make connections with those other peers that are geographically closer to it. There are many solutions that are suggested for locality problem. In this paper, we suggest a Cube Connected Cycle as an overlay network to improve locality with higher performance  

Today, peer-to-peer networks are become more popular among internet users and more than millions peers share high volume of data from anywhere. Sending and receiving these data increase the network traffics terribly. By improving the performance of these networks not only the efficiency of these networks increase but also the overall performance of the internet augments. To achieve high performance and resilience to failures, a peer can make connections with those other peers that are geographically closer to it. In this paper, we present a novel mechanism for placing peers on the overlay network, which supports locality without increasing network traffic seriously  

Non-malleable codes are kind of encoding schemes which are resilient to tampering attacks. The main idea behind the non-malleable coding is that the adversary can't be able to obtain any valuable information about the message. Non-malleable codes are used in tamper resilient cryptography and protecting memory against tampering attacks. Several kinds of definitions for the non-malleability exist in the literature. The Continuous non-malleability is aiming to protect messages against the adversary who issues polynomially many tampering queries. The first continuous non-malleable encoding scheme has been proposed by Faust et al. (FMNV) in 2014. In this paper, we propose a new method for proving... 

This paper proposes a hierarchical outage management scheme to enhance the resilience of a smart distribution system comprised of multi-microgrids against unexpected disaster events. In this regard, after identifying the main features and requirements for a resilient outage management scheme, an appropriate framework is devised and the roles and tasks of different management entities in a multi-microgrids system are introduced. Based on this framework, the microgrids schedule their available resources in the first stage using a novel model predictive control-based algorithm. In the second stage, distribution system operator coordinates the possible power transfers among the microgrids and... 

A disaster is an adverse event resulting from natural processes of the Earth or sometimes from terrorist attacks. Since the concept of disaster resilience has become prominent, research and practice for making the cities resilient play an important role in urban management. Cities are composed of a variety of structures and providing the structural resiliency can protect them. Resilient structures are composed of a number of ideal performance criteria, which based on analysis, experiment, and past experience, are capable to withstand the required level of stress and deformation. In addition, durability, fire resistance, and other capabilities, such as being environmentally friendly with no...