Sharif Digital Repository

Nowadays, wireless communications for multimedia purposes is widely spreaded especially due to video communication demands. One of important considerations in this area is to receive video stream with less effect of errors related to transition channel as well as optimal utilization of bandwidth. The H.264 is exploited as the most efficient video compression standard and because of its predictive nature of encoder and decoder, it is very sensitive to error propagation, so error resilient technics should be applied along with the video compression to reduce the visual impacts of error occurrence and propagation. In this thesis existing methods of video error resilience, video quality measures... 

In the recent years, emerging vehicular ad hoc networks offer a wide variety of applications, including safety, convenience and entertainment. One of the beneficial applications in these fields is video streaming. However, according to the features like high mobility and loss of links, establishment of video streaming which requires stringent Quality of Service is a daunting task. In this thesis, the goal is introducing approaches in two levels, one for resilient video coding and the other one for network routing. For resilient video coding, the concentration is on the scalable video coding, which supports various applications for users with different requirements. The introduced approach... 

Video communications over mobile ad hoc networks is increasingly deployable as these networks become deployed in various applications such as disaster recovery. Error-prone nature of the mobile ad hoc networks and the vulnerability of compressed video to packet losses have brought many challenges to realize video transmission over MANETs. In this thesis, it is tried to achieve a good quality of service by resilient video coding and multipath transmission over mobile ad hoc networks. To generate error resilient video, a hybrid method is used by combining scalable video coding and multiple description video coding techniques. First, the video sequence is coded to two layers and then each layer... 

Side channel attacks, where an attacker learns some physical information about the state of a device, are one of the ways in which cryptographic schemes are broken in practice. leakage resilient ryptography addressed this issue at a higher abstraction level, proposing models capturing such attacks. Auxiliary Input is one of these models. In this thesis, we study public-key encryption schemes in this model of leakage. we also propose a method to consider this leakage continuously (i.e., not just one observation of the adversary). at the end, we consider the leakage from both the secret key owner and the encryptor. This odel captures a wider class of side-channel attacks  

Supplier selection and order quantity allocation problem is one of the most complex making decision problems comes into account. In the past, supplier selection done based on criteria such as price, quality and delivery time. Today's supply chains with the aim of expanding business activities and improving their performances, Follow process such as outsourcing, product development, and selection of multi-supplier strategies. This conditions will bring opportunities and threats for supply chains. One of the possible risks to supply chains are disruption risks and disruption has been a great concern in the past decade and disruption of suppliers are one of the new topics that have recently... 

In recent years, climate change due to greenhouse gases caused an increase in frequency and intensity of the natural disasters such as hurricanes, blizzards and floods. Moreover, it is anticipated that such events will increase in the future. As a result, power system decision makers are looking for methods to improve power system resiliency against such natural disasters with low occurrence probability and high impact. In this report, the distribution system resiliency has improved via placing remote control sectionalizing switches and micro grids formation during natural disasters. In this regard, the concept of resiliency and its characteristics along with the effect of remote control... 

The concept of smart grid to realize the triple goals of economy, reliability and environmental improvements has taken advantage of modern equipment and new structures. Beside these goals smart grids seek to increase the level of penetration of renewable resources for environmental improvement. On the other hand, increase in dispersed products and problems resulting from increasing these non-dispatchable resources thus led the researches to design a new structure called microgrid. Microgrid improves the reliability of these resources and facilities their uses. But uncertainty and intermittency in producing renewable energy resources are among the main challenges facing these microgrids.... 

As a result of numerous earthquakes happened in recent decades, widespread failures were observed in conventional braced frames, which were mostly created due to buckling of the braces under compression. To find a solution to overcome this problem, Ribbed Bracing System (RBS) was developed by Golafshani et al. in 2004. In this study, continuing the experimental investigation and considering the previous outcomes, the RBS bracing was redesigned based on some modifications. Then, two half-scale RBS braces with pinned frames were constructed and tested under cyclic loading. RBS systems were utilized in two options, CC-RBS and SC-RBS, in X configuration, the first of which was constantly... 

This dissertation proposes a new platform and a new software for evaluation of urban Water Distribution Network (WDN) resilience. Resilience is considerd as the ability of an infrastructure to come back to steady state after being affected by any environmental or man-made disturbance. WDN, as an essential infrastructure, has major role on resilience and sustainability of cities and communities. Today, uninterrupted performance of WDN is a basic need of people who live in cities. This uninterrupted performance becomes bolder in face of man-made or natural disasters like earthquake. The uninterrupted performance of a system is dependent on the system’s resilience. Majority of researchers... 

Occurrence of natural disasters such as flood, windstorms, tsunamis and earthquakes has caused striking effects on critical infrastructures like power systems in recent decades. There are some examples of high-impact low-possibility (HILP) events which causes catastrophic effects on power systems. Traditionally, planning and operational studies of power system have been run taking into account some reliability metrics. Although, the reliability indices can represent the ability of a system in confronting with possible failures of components, they are unable to efficiently consider the effects of severe events such as earthquake and other HILP events. Moreover, traditional power systems were... 

In the aftermath of earthquakes, hospitals serve the critical role of treating casualties and reducing mortalities and severe injuries. A hospital must be resilient to play its role correctly after the earthquake. A resilient hospital is able to maintain its functionality at an acceptable level and provide service to the injured. In order to enhance the resilience of a hospital, an appropriate framework is needed to evaluate the hospital resilience and determines the impact of modification actions. This framework should characterize the serviceability of a hospital in terms of an appropriate metric. In this framework, the behavior of a given hospital building in the event of an earthquake as... 

In this thesis the resilience of a neural network is examined under structural perturbation.The network consists of Spiking neurons with specific dynamics or they are binary neurons and the network is non-spiking. Neural network is a multi-dimensional and multi-stable system therefore we can map their dynamical equations to effective one-dimensional equation with one parameter which shows the environmental conditions.The resilience of the system is evaluated with respect to changes in weights and edges of the network and the the resilience pattern of the system is obtained.Finally, the recovery and control methods are briefly discussed  

The aim of this research is presentation of A framework to select the appropriate combination of retrofit and insurance in order to reduce earthquake losses. The vulnerability of buildings to earthquakes can lead to significant damage to owners and residents of these buildings. It is imperative that appropriate measures be taken to reduce these adverse effects before the risk occurs. Some of these measures, such as seismic retrofit of buildings, can reduce the vulnerability of buildings and, consequently, financial and human losses. Some other measures like insurance, in the event of an earthquake, can reduce the financial losses incurred by owners and residents of vulnerable buildings.... 

Security analysis of cryptographic systems against implementation attacks, including active and passive attacks, is an important issue due to the large number of such attacks in the real world. Since 2000’s, cryptographers have begun attempting to model active and passive attacks to implementation of cryptographic algorithms. At first, cryptographers modeled the attackers with ability to exploit leakaged information, leading to leakage-resilient cryptography. Afterwards, cryptographers modeled the attackers with ability to tamper with the cryptographic algorithms which led to tamper-resilient cryptography. Actually, the major proposed cryptographic primitive dealing with tampering is the... 

The design and planning of resilient supply chains is a major challenge due to the increasing complexity of these systems that operate in a global market and therefore are more exposed to disruptions. Present work aims to apply principle of resiliency in a supply chain by simulation. A case study of Shahab Company is used to illustrate the effect of redundancy and agility on its resiliency. We simulate the relationships of Shahab Company with its suppliers, and the suppliers with their sources and investigate the effects of disruptions in the model. Shahab Company has two main supplier and they own sources. To evaluate the designed model, two performance measures were defined, inventory and... 

Natural disasters, earthquakes in particular, claim many human lives and damage major lifelines such as transportation networks. Transportation networks play an important role in various stages of response to disasters, such as evacuation, search, rescue and reconstruction missions. Hence, special attention must be paid to transportation networks in any disaster management system. Hence, in order to reduce the impacts of earthquakes on denser cities and metropolitan areas, analysis of the resiliency and vulnerability of critical infrastructures such as transportation network, can be used as an effective strategy.The resiliency and vulnerability of transportation network have attract a lot... 

Natural hazards such as earthquake take many lives each year and cause significant damages to infrastructures such as transportation networks. Whether after occurrence of a natural disaster like storm in order to evacuate, or after an abrupt event such as earthquake in order to provide emergency measures, a transportation network should maintain its functionality and performance in an acceptable degree and should recover in an effectively short period of time. In this study, the link or the set of links which their removal causes significant damage to the transportation network are identified. A specific index (N-Q index) has been used to describe the performance of the network. In addition,... 

Back then and still now natural calamities have been a serious threat for energy systems. On that front, this thesis constitutes a three-stage mixed integer linear programming (MILP) model to enhance the resilience of power distribution systems to deal with disas-trous events. The proposed model involves in pre-, mid-, and post-event stages. In this con-text, to increase the preparedness of the power distribution system, system operator recon-figures the system by taking benefit of remote-control switches (RCSs), manual switches (MSs), and distributed generations (DGs) before the natural calamity hits. The proposed model contemplates the traveling time of crew teams to the MS sites in order... 

This study proposes a probabilistic framework to quantitatively evaluate the resilience of a community comprising a building stock, commercial facilities, and interdependent infrastructure systems. To this end, the proposed framework employs Monte Carlo sampling in which each sample comprises multiple stages. The sample starts with the occurrence of a hazard event. It then follows by evaluating the consequences incurred by the community in the face of the hazard event. It is concluded by simulating the operations aimed at complete recovery of the community comprising inspection, rescue and relief, restoration, and recovery. For this purpose, chains of interacting probabilistic models are... 

This thesis proposes a probabilistic modeling framework for networked infrastructure systems in community resilience analysis. In particular, the framework is presented for the electric power infrastructure. Models are proposed at two levels of refinement. The basic model only determines the connectivity of different elements in the network, whereas the refined model also quantifies the amount of the power transmitted through the network elements. In a community resilience analysis, the proposed basic model provides a rather simple tool to determine those buildings and infrastructure systems that suffer from power outage when the supplying power station loses connectivity with the network....