Sharif Digital Repository

Network management includes a wide range of topics such as performance, security, monitoring, debugging and so on. The network monitoring plays a vital role and can cover a wide range of network management requirements. Monitoring is the only way to know the correct network performance in accordance with the network design. In order to understand what is happening on the network and how network performance over time, the network should have a reporting system. Today, the reporting is done using network monitoring tools. In traditional networks, network monitoring is done using additional hardware which imposes high costs, complexity and also additional traffic overheads to the network. But... 

Software Defined Networks provide programmability and centralized control for network’s administrator. Like other networks, security problems are important in these networks, but there is not enough research in this area. The problem being discussed here is to elevate the security level in software defined networks using centralized control and programmability of these networks. We will accomplish this purpose by using hosts and controller at the same time to prevent unwanted traffic from entering the network. By using this approach, we will be able to remove many short comings of these networks and implement security systems, like intrusion detection systems, more efficient. One of these... 

Wireless technology can now be seen almost everywhere. This technology has recently become very popular, and with the convenience that comes with its use, it will probably be the most commonly used technology among computer networks in the near future. Unfortunately, new technology is always under fire when it comes to security.So that this type of network security has become a big challenge for them.
The researchers approach to security in wireless networks that have a lot of attention is the use of intrusion detection systems. An intrusion detection system (IDS) monitors network traffic and monitors for suspicious activity and alerts the system or network administrator. In some cases... 

Network methods have had profound influence in many domains and fields in the past decade. Community structure is a very important property of complex networks, but the precise definition of a community remains an unresolved problem and Community detection in complex networks has recently attracted wide attention in several research areas such as social networks, communication networks, and biological systems. Complex network studies grow by the scientific community, thanks to the increasing accessibility of real-world network data. The emphasis of use analysis on the network algorithms and community structure is one of the most important problems in the field of complex network. Many... 

With the introduction of SDN and OpenFlow as novel approaches for better network management and virtualization, it is now easier to perform QoS measurement anywhere, anytime, and anyplace through the use of self-directed, self-tuning mechanisms that continuously monitor and measure network performance and react swiftly to problems. Using programmable interfaces to OpenFlow controllers, software-defined measurement solutions provide consistent traffic measurement of flow parameters, such as bandwidth, packet loss, and latency to support the diversity requirements of next generation network applications and services. The flexibility of software-defined measurement gives the network operator... 

Complex networks represent a wide diversity of systems in nature and human interactions. Networks are graphs that describe the structures of interacting systems and give significant information about the patterns of connections between the nodes in a particular system. In turn, having knowledge about the structure of networks and their arrangements enables one to make certain types of predictions about their behavior of network.Network methods have had profound influence in many domains and fields in the past decade. Centrality measures are very important tool for analysis complex networks, in real-world complex networks are heterogeneous structures, all their components such as nodes... 

Indoor Positioning Systems (IPS) are commonly used in context-aware environments in order to determine the location of any desired object. In such environments location awareness is a key to adequate response. There are several positioning technologies available such as beacon-based positioning, camera-based positioning, Wi-Fi positioning, etc. Among these positioning systems Radio Frequency Identification (RFID) positioning has significant advantages over other technologies. Flexibility, ease of implementation, cost and accuracy are key advantages for RFID positioning technology. RFID positioning systems are classified in three categories: RF signal analysis-based, active RFID and passive... 

The Vehicular Ad hoc Network (VANET) have been presented to enhance the safety and comfort of driver and passengers. Thus, the functionality of VANET is related to the accuracy of disseminated messages about surrounding environment. Therefore, it is critical to detect the true reports among false reports which they have been reported by malicious nodes. However, in this research, the proposed scheme presents a centralized trust management assessment scheme named Detection of Best Report (DBR) in vehicular ad hoc environments. Each received message is evaluated individually according to its reporter interactions during event reporting. Based on this evaluation in RSU, the most reliable nodes... 

Optimization of energy consumption is generally important in mobile networks and in particular in automotive networks. One of the challenges of installing roadside units in automotive case networks is to provide energy to the equipment assigned to these units. In some cases, power is easily available, but in many places, the cost of energy is very high and does not have economic justification. Therefore, optimization of energy consumption in roadside unit is of great importance. Typically, vehicles limitations in terms of energy consumption for communications are far lower than that of a roadside unit. In this dissertation, part of roadside communication to vehicles is shifted to the... 

Reducing energy consumption is one of the challenges facing wireless sensor networks with many solutions introduced for them with each having advantages and disadvantages. Some of the solutions introduced are based on using movable sinks. In this project, we attempt at proposing a place for the establishment of sinks using genetic algorithm that can reduce energy consumption in the net knots and increase the net life. This work should be done after reviewing the results of past researches and introduced methods. We will analyze the practicality of the proposed model using simulation and will show their advantages over the previous mentioned methods  

In 2008, a decentralized and distributed payment solution called Bitcoin was born. Since then, it has made the payment industry think about banks and companies on the one hand and government authorities on the other. By using mathematics and cryptography, Bitcoin was able to eliminate the need for trust and in this way it was able to eliminate intermediaries such as banks. In traditional financial affairs such as banks, the user must trust the bank and everything relies on the bank’s servers. While Bitcoin stores the history of transactions in a public and distributed ledger. This ledger is encrypted so that the state of the blockchain is always reliable. In Bitcoin’s decentralized and... 

Along with the emergence of the smart city concept and the increasing demand for a wide range of vehicles, the Internet of Vehicles (IoV) has attracted a lot of attention by providing numerous benefits including vehicle accident warning, reducing pollution levels and traffic congestion, as well as entertainment services. Furthermore, IoV offers various services combining Vehicular ad hoc networks (VANETs) and IoT in smart cities. However, these types of networks are exposed to a variety of security and privacy risks due to the wireless nature, because the sensitive message is transmitted through an insecure channel in the IoV-based smart city environment, therefore, it is necessary to... 

Focusing on developing the EEPS (Energy Electric and Power System) based on the SG (Smart Grid) infrastructure to achieve implementation of EI (Energy Internet) ultimately, in order to analyze and manage the energy/power consumption, requires a robust embedded EMS (Energy Management System) to implement real-time LF (Load Forecasting), prevent the power waste and realize consumption management which eventually leads toward the smart industries/buildings. STLF (Short Term Load Forecasting) is an essential component that an industrial plant requires to manage the power, regarding the load fluctuations during production, and compulsory requirement of cost mitigation. This thesis, in order to... 

The main idea of the upcoming research is to provide a way of benefiting from processing at the edge and processing in the fog for the open source platform openremote; In such a way that the central core of the platform can offload its processing tasks to the edge of the network. With this work, a large amount of the processes that used to be done by the core will be offloaded from the core. On the other hand, by applying processes at the edge of the network, it becomes possible to eliminate a large amount of overhead caused by raw data transmission, and as a result, the productivity of the network increases. In the current research, in addition to designing a model to add the mentioned... 

The stock market is vital to the economy as it serves as a key indicator of economic health. AI algorithms can process vast amounts of market data at high speeds, identifying patterns and trends that are often invisible to human analysts. Forecasting future stock trends poses significant challenges due to the complex inter-stock and intra-stock dynamics that influence stock prices. Recently, graph neural networks have shown promising results by modeling multiple stocks as graph-structured data. However, many of these approaches depend on manually defined factors to construct static stock graphs, which fail to capture the rapidly changing interdependencies between stocks. In this work,... 

In opportunistic networks, the nodes have ad-hoc communications that are formed directly between them, without any infrastructure, and not by any using any other intermediate node. In case that the destination node is not in the same region as the source during the sending of a message, the source will send the message to one or a few of its neighbors so that they can store and carry out the message to the original destination in cooperation known as Store-Carry-Forward Mechanism. Remarkably, in most cases, the devices involving in this type of network, e.g., smartphones, have limited source of energy or they use a battery, there is a need to minimize the energy consumption in the nodes.... 

Mobility is one of the most challenging issues in mobile Ad-Hoc networks which has a significant impact on performance of network protocols. To cope with this issue, the protocol designers should be able to analyze the movement of mobile nodes in a particular wireless network. In this thesis, a new framework called Mobility Analyzer has been proposed. At first, Mobility Analyzer categorizes mobility models based on their mobility characteristics; subsequently, it uses mobility metrics for evaluating mobility traces which are collected by GPS or generated by mobility simulators. Finally, Mobility Analyzer recognizes the mobility model of mobility traces based on mobility metrics and measures... 

Recent researches show inefficient use of frequency spectrum such that there is shortage of frequency in operation. In order to overcome this problem cognitive radio are introduced that opportunist usage of frequency band is their prominent characteristic. Problems and challenges caused by using these networks are wide and increasing. In this thesis we focus on improving resource management algorithms in cognitive radio. In this study in order to have a dynamic and efficient management in choosing reliable and quality channels, reinforcement learning algorithms are used based upon existing data and experiences. Since this tool has the learning capability and analysis in dynamic situation of... 

Data aggregation is an efficient method to conserve energy by reducing packet transmissions in Wireless Sensor Networks. However, providing end-to-end data reliability is a major challenge when the network uses data aggregation. In this case a packet loss can miss a complete subtree of values, so greatly affect final results. Data transmission in multiple paths can tolerate this problem, but it may incur some computational error for duplicate-sensitive aggregates when aggregating individual sensor values multiple times. In this thesis, we have proposed a reliable data Aggregation protocol which uses the available path redundancy to deliver a correct aggregate result to the sink with a high... 

In recent decades, Securing mobile ad hoc networks has attracted much attention. Today, several security tools, such as intrusion detection systems are used in the network. Methods based IDS works on pattern recognition and anomaly detection are divided into two categories. Pattern recognition methods based on known attack patterns work with high detection rate, but do not have the ability to detect new attacks. Anomaly detection techniques have the ability to detect new attacks, but they have high false alarm rate.
In this thesis, an anomaly detection system based on artificial immune designed, implemented and evaluated.For example, an anomaly detection methods such cases, a variety of...