Software defined network (SDN) is a new modern network technology which decouples control plane and data plane to simplify network management. The separation of control plane from data plane arises ...the control placement problem (CPP) in these networks. The main questions in the CPP are (1) how many controllers are required to be used in such networks and (2) where these controllers should be placed. To achieve an efficient solution for such problem in SDN, we define the CPP as a multi-objective combinational optimization problem in this paper and solve the CPP by applying the antlion optimization algorithm on it. We consider three metrics for the CPP: (a) Inter-controllers latency, (b) switch to controller latency, and (c) multiple disjoint connectivity paths between switches and controllers. We evaluate our proposed solution by performing several experiments using different real network topologies. Experimental results show that our proposed solution provides better performance compared to the existing solutions.
Advanced persistent threat attacks are considered as a serious risk to almost any infrastructure since attackers are constantly changing and evolving their advanced techniques and methods. It is ...difficult to use traditional defense for detecting the advanced persistent threat attacks and protect network information. The detection of advanced persistent threat attack is usually mixed with many other attacks. Therefore, it is necessary to have a solution that is safe from error and failure in detecting them. In this paper, an intelligent approach is proposed called “APT-Dt-KC” to analyze, identify, and prevent cyber-attacks using the cyber-kill chain model and matching its fuzzy characteristics with the advanced persistent threat attack. In APT-Dt-KC, Pearson correlation test is used to reduce the amount of processing data, and then, a hybrid intrusion detection method is proposed using Bayesian classification algorithm and fuzzy analytical hierarchy process. The experimental results show that APT-Dt-KC has a false positive rate and false negative rate 1.9% and 3.6% less than the existing approach, respectively. The accuracy and detection rate of APT-Dt-KC has reached 98% with an average improvement of 5% over the existing approach.
Broadcasting is one of the basic ways to access XML data via mobile wireless networks. In these networks, XML data are disseminated over a wireless broadcast channel and mobile clients can connect to ...this channel via portable devices and receive the XML data they need. To date, various indexing methods have been proposed to broadcast the XML data over mobile wireless broadcast networks, each of which attempts to reduce the latency and energy consumption of mobile devices in processing the different types of XML queries. Most of the proposed indexing methods use only a single wireless broadcast channel for XML data dissemination. Due to the sequential data access over a wireless broadcast channel, the access time to retrieve the desired XML data over a broadcast channel is longer if the length of generated XML data stream is large. This paper proposes two new XML data placement schemes to disseminate the XML data over multiple wireless broadcast channels by partitioning the XML data stream into several partitions and placing them into multiple wireless broadcast channels. The goal of both of which is a further reduction of the access time during the process of XML querying over the broadcast channels. According to the experimental results, the proposed XML data placement schemes have achieved the goal of further reducing the access time, especially when the size of XML document to be disseminated is large.
In recent years, the development of IOTA, a new type of Distributed Ledger (DL) for internet of things (IoT), has gained significant attention. IOTA DL offers key features like scalability, fast and ...free transactions, making it an optimal choice for IoT devices. However, a major concern with IOTA DL is its reliance on a single coordinator for transaction confirmation. This default coordinator introduces issues of single point of failure and incomplete distribution. To address these limitations, this paper proposes the Multiple Coordinator Selection (MCS) algorithm. MCS aims to overcome the problem by involving multiple coordinators in the consensus process. Four metrics, namely "trust level," "distance from input transactions," "node activity," and "transaction distribution," are defined as properties for coordinator selection. Additionally, a checklist is employed to minimize the probability of collusion within the system. Furthermore, the paper introduces a three-layered architecture based on cloud and fog computing, where the MCS algorithm is implemented. Experimental results demonstrate improved security and distribution of the system, while reducing the chances of collusion and single point of failure.
Todays, XML as a de facto standard is used to broadcast data over mobile wireless networks. In these networks, mobile clients send their XML queries over a wireless broadcast channel and recieve ...their desired XML data from the channel. However, downloading the whole XML data by a mobile device is a challenge since the mobile devices used by clients are small battery powered devices with limited resources. To meet this challenge, the XML data should be indexed in such a way that the desired XML data can be found easily and only such data can be downloaded instead of the whole XML data by the mobile clients. Several indexing methods are proposed to selectively access the XML data over an XML stream. However, the existing indexing methods cause an increase in the size of XML stream by including some extra information over the XML stream. In this paper, a new XML stream structure is proposed to disseminate the XML data over a broadcast channel by grouping and summarizing the structural information of XML nodes. By summarizing such information, the size of XML stream can be reduced and therefore, the latency of retrieving the desired XML data over a wirless broadcast channel can be reduced. The proposed XML stream structure also contains indexes in order to skip from the irrelevant parts over the XML stream. It therefore can reduce the energy consumption of mobile devices in downloading the results of XML queries. In addition, our proposed XML stream structure can process different types of XML queries and experimental results showed that it improves the performace of XML query processing over the XML data stream compared to the existing research works in terms of access and tuning times.
In mobile wireless broadcast networks, XML data is encrypted before it is sent over the broadcast channel in order to ensure the confidentiality of XML data. In these networks, mobile clients must ...not have access to all the XML data; rather they should have access to some parts of the XML data that are relevant to them and to which they are authorized to have access. In this paper, a new encrypted XML data stream structure is proposed which supports the confidentiality of XML data over the broadcast channel. In our proposed stream structure, the size of encrypted XML data stream is reduced by grouping the paths, XML nodes, texts, and attributes together. The proposed structure includes several indexes to skip from irrelevant data over the broadcast channel. The experimental results demonstrate that the use of our proposed stream structure efficiently disseminates XML data in mobile wireless broadcast networks in a secure manner and the indexes in our proposed stream structure improve the performance of XML query processing over the encrypted XML data stream.
•A new structure for streaming the XML data is proposed which guarantees confidentiality of the XML data over the wireless stream.•An access mechanism is proposed to efficiently process XML queries ...over the encrypted XML stream.
Recently, the use of XML for data broadcasting in mobile wireless networks has gained many attentions. One of the most essential requirements for such networks is data confidentiality. In order to secure XML data broadcast in mobile wireless networks, mobile clients should obey a set of access authorizations specified on the original XML document. In such environments, mobile clients can only access authorized parts of encrypted XML stream based on their access authorizations. Several indexing methods have been proposed in order to have selective access to XML data over the XML stream. However, these indexing methods cannot be used for encrypted XML data. In this paper, we define a new structure for XML stream which supports data confidentiality of XML data over the wireless broadcast channel. We also define an access mechanism for our proposed structure to efficiently process XML queries over the encrypted XML stream. The experimental results demonstrate that the use of our proposed structure and access mechanism for XML data broadcast efficiently disseminates XML data in mobile wireless networks.
A data stream exhibits as a massive unbounded sequence of data elements continuously generated at a high rate. Stream databases raise new challenges for query processing due to both the streaming ...nature of data which constantly changes over time and the wider range of queries submitted by the user when compared with the traditional databases. In this paper, we propose a system architecture which includes components for both distributed indexing of streaming data and distributed processing of range queries on streaming data. Instead of creating a large and centralized B+Tree index structure, we create a set of small B+Tree indexes in such a way that a B+Tree index can be created for every partition of streaming data. We also design a distributed range search algorithm which can be used by each individual machine inside a Spark cluster to independently process range queries on each partition of streaming data. By exploiting the proposed system architecture, the process of indexing of streaming data and the process of querying over streaming data can be performed in a distributed and parallel manner. By performing several experiments, we demonstrate that our proposed indexing method is scalable and efficient for processing range queries on streaming data compared to the existing centralized B+Tree indexing methods and therefore, it can be used for applications involving data streams with a large volume of data elements and a large number of range queries.
Blockchain networks are consistently challenged with security and accessibility issues, and technological developments call for the need for their security and integrity more than ever. Security ...vulnerabilities such as distributed denial-of-service (DDoS) attacks and Eclipse attacks influence public and private blockchains imposing significant losses to the network. Considering the key distribution and management service as a major part of the blockchain architecture, the present study proposes a combinatorial design-based token management system (CD-TMS) while offering optimum accessibility for the blockchain network. Our combinatorial design-based, clustered tokenization system enables the blockchain to prevent DDoS attacks. We also offer a leader selection mechanism relying on a probabilistic tokenization system that reduces communication overhead compared to voting-based systems. In this regard, CD-TMS integrates Balanced incomplete block designs and transversal designs (TD), as well as Eschenauer and Gligor (EG) designs, to distribute tokens on a public blockchain framework (i.e., Bitcoin), though it focuses mainly on DDoS and Eclipse attacks. The performance function, evaluated in terms of security, resiliency, communication overhead, connectivity, reliability, availability, and scalability, has shown the proposed architecture's superiority over conventional methods.
