Статьи журнала - International Journal of Wireless and Microwave Technologies
Все статьи: 454
Adaptive HEC-VPS: The Real-time Reliable Wireless Multimedia Multicast Scheme
Статья научная
To satisfy the reliability of real-time wireless multimedia multicast services, the existing erasure error correction schemes usually assume that the packet size in transmissions is fixed. However, recent studies have shown that Variable Packet Size (VPS) can deeply influence the performance of unicast wireless services. Accordingly, using a delay-limited general architecture of EEC for real-time wireless multicast, this paper proposes an Adaptive Hybrid Error Correction (AHEC) scheme with VPS. Comparing with the AHEC schemes with fixed packet size, the analysis results show that the AHEC with VPS scheme can improve the throughput by about 10% in some cases.
Бесплатно
Adaptive Multi User Detection for FD-MC-CDMA in Presence of CFO
Статья научная
The main targets of multi-carrier direct sequence code division multiple access (MC-DS-CDMA) mobile communication systems are to overcome the multi-path fading influences as well as the near-far effect and to increase its capacity. Different types of optimal and suboptimal multi-user detection schemes have been proposed and analyzed in literature. Unfortunately, most of them share the drawback of requiring an efficient practical solution. Genetic algorithm provides a more robust and efficient approach for solving complex real world problem such as multi user detection, but genetic algorithms are not computationally efficient. Computational complexity and performance of the genetic algorithms depends on number of generations and/or the population size, schemes involving genetic algorithms would compromise in computational complexity or performance. In this paper we propose adaptive population sizing genetic algorithm based multi user detection algorithm and compare its performance with existing multi user detection algorithms in various channels. Simulation results confirmed that the proposed adaptive genetic algorithm assisted multi user detection algorithm performs better compared to the existing multi user detection algorithms.
Бесплатно
Adversarial Machine Learning Attacks and Defenses in Network Intrusion Detection Systems
Статья научная
Machine learning is now being used for applications ranging from healthcare to network security. However, machine learning models can be easily fooled into making mistakes using adversarial machine learning attacks. In this article, we focus on the evasion attacks against Network Intrusion Detection System (NIDS) and specifically on designing novel adversarial attacks and defenses using adversarial training. We propose white box attacks against intrusion detection systems. Under these attacks, the detection accuracy of model suffered significantly. Also, we propose a defense mechanism against adversarial attacks using adversarial sample augmented training. The biggest advantage of proposed defense is that it doesn’t require any modification to deep neural network architecture or any additional hyperparameter tuning. The gain in accuracy using very small adversarial samples for training deep neural network was however found to be significant.
Бесплатно
An Analysis of VoIP Application in Fixed and Mobile WiMAX Networks
Статья научная
WiMAX is a wireless broadband technology, which promises maximum coverage area and high data rates. WiMAX provides last mile connectivity. This network defines two working models such as fixed WiMAX and mobile WiMAX. The main aim of this paper is to compare and also analyze the performance of the VoIP application over fixed and mobile WiMAX, with respect to various codecs such as G.711, G.723.1ar5.3, G.726ar24, G.728ar16 and G.729. We have considered few QoS parameters such as average end-to-end delay, throughput, average jitter, average one-way delay and average MOS. From the obtained result, codec G.711 and G.726ar24 performs better when compared to other codecs in both fixed and mobile WiMAX network.
Бесплатно
An Approach Towards Dynamic Opportunistic Routing in Wireless Mesh Networks
Статья научная
Opportunistic routing (OR) for multi-hop wireless networks was first proposed by Biswas and Morris in 2004, but again as a modified version in 2005 as Extremely Opportunistic Routing (ExOR). A few other variants of the same were also proposed in the meanwhile time. In this paper we propose a Dynamic Opportunistic Routing (DOR) protocol which depends on network density and also provides spatial diversity. Our routing protocol is distributed in nature and provides partial 802.11 MAC layer abstraction. To verify the results of our protocol we took a network with light-density of nodes and bigger in size (as OR performs better in higher node density). A wireless mesh network in “QualNet network simulator” was created, where the average end-to-end delay and throughput at every node are compared with that of other standard routing protocol OLSR-INRIA.
Бесплатно
An Approach to Micro-blog Sentiment Intensity Computing Based on Public Opinion Corpus
Статья научная
Based on the analysis of the status of network public opinion, the features of short content and nearly real-time broadcasting velocity in this paper, it constructs a public opinion corpus on the content of micro-blog information, and proposes an approach to marking corpus on the basis of sentiment tendency from the semantic point of view; Furthermore, considering the characteristics of micro-blog, it calculates the sentiment intensity from three levels on words, sentences and documents respectively, which improves the efficiency of the public opinion characteristics analysis and supervision. So as to provide a better technical support for content auditing and public opinion monitoring for micro-blog platform.
Бесплатно
An Efficient and Cloud Based Architecture for Smart Grid Security
Статья научная
Due to explosive growth of users, increasing energy demand and also the need to improve efficiency and maintain the stability of the electricity grid, smart grid is the only option available to electrical industry engineers. In fact, the smart grid is a physical-cyber system that provides coherent and integrated communication, processing and control functions. The smart grid provides control and management of millions of devices in the electricity industry in a reliable, scalable, cost-effective, real time and two-sided manner. Given the increasing growth of cyber threats in the last decade, the need to protect the electricity industry and its critical systems seems essential. The slightest disruption to the power industry's systems results in disruption to other industries, reduced productivity, and discontent. Hence we proposed an efficient cloud based architecture to improve smart grid performance. Proposed architecture provides data security and privacy against different types of cyber threats such as replay attack, modification attack and so on.
Бесплатно
An Efficient and Comapct Design of Coupled-Line Unequal Wilkinson Power Divider
Статья научная
In this paper, 3:1 and 10:1 unequal Wilkinson power dividers are designed and investigated. Unequal power dividers are an integral part of the feeding network for antenna array where their performance affects a group of elements rather than an individual element. Thus, there is a need for an accurate design for such dividers. A coupled-line section with two grounding via has been used to attain the high characteristic impedance line. This is done in order to outplay the microstrip fabrication constraints of printing very thin/fine conductor lines. Further to reduce the size of the structure, meandering of the transmission line has been done which procreates three designs, namely: 00 Serpentine Flexure, 1800 Serpentine Flexure and Compact Meandered Flexure. Verification of the design methodology has been done by creating a 10:1 Unequal WPD. The structures are implemented on a high-resistive silicon substrate (HRS) for a centre frequency of 1.575 GHz. Further, their EM analysis is done in terms of S-parameters such as return loss and insertion loss using commercially available FEM solver. Satisfactory RF performance, with return loss better than -10 dB and required power split for all the structures, has been achieved.
Бесплатно
An Energy Efficient Routing Algorithm for Wireless Body Area Network
Статья научная
Wireless body area networks (WBANs) are emerging as one of the newest forms of Wireless Sensor Networks. In WBANs, sensor nodes accumulate human physiological data and transmit it to the sink node. However, transmission of physiological data to the sink node over a mobile route becomes a very daunting task for sensors due to their limited battery power. Moreover, replacement of critical sensor nodes is a major challenge in such scenarios. In order to increase network lifetime, some routing protocols have been proposed in the literature, but the majority of them are focused on coverage distance and residual energy of sensor nodes. In this work, we will propose an energy efficient routing algorithm for WBANs that will take into consideration two additional attributes (node criticality and communication count) along with the above stated attributes. These four parameters in the proposed algorithm will result in enhancement of working lifetime of the network via less energy consumption in comparison to existing routing protocols.
Бесплатно
An Enhanced LEACH Routing Algorithm for Energy Conservation in A Wireless Sensor Network
Статья научная
It has been well established that the lifetime of a Wireless Sensor Network (WSN) depends on the energy of the sensor nodes which is limited by the battery capacity of the nodes. This challenge has led to research efforts towards developing a more efficient energy based routing algorithms and architectures. One of such popular algorithm is the Low-Energy Adaptive Clustering Hierarchy (LEACH). The LEACH approach adopts randomized rotation of local base stations (or cluster-heads (CH)) to evenly distribute energy load amongst the sensors in the network. A variant of LEACH known as Vice-LEACH (V-LEACH) introduces the concept of a vice-CH that takes over the role of the main CH in the event of CH death. Random selection of cluster- head node in both LEACH and V-LEACH ignore node's residual energy and the optimal number and distribution of cluster head is not ensured in all rounds. This work presents an enhanced cluster-based routing algorithm which took into consideration the residual energy of nodes in the network while maintaining the optimal number of CHs throughout the network lifetime. A sensor network was developed on OPNET Modeler software tool and simulation tests were performed to evaluate the performance of the enhanced routing algorithm on the network. Simulation results showed that this enhanced routing algorithm distributed network energy consumption across the network nodes hence significantly improving the lifetime of the sensor network.
Бесплатно
An Enhanced Reputation-based for Detecting Misbehaving Nodes in MANET
Статья научная
In this paper, we propose an enhanced approach based on first-hand reputation with allows to detected misbehavior node in Manet. The network's security is an important challenge in this kind of networks. The main objective of the misbehaving nodes in AODV routing protocol deletes all data packets that received thus, don’t transmit to their destination. In a reputation-based system, each node overhears the activity of its neighbors (transmit and receive) in first-hand or combined with second-hand. Our approach is composed of three-phase directly monitoring, calculating reputation value and node isolation. The reputation value is enhanced by the packet dropped due to other events such as overloading of queue and node availability. The node with a negative reputation will be isolated, and an alert packet will be distributed to neighboring nodes to inform, afterwards an improved local repair is started. The simulation results show that the proposed approach can detect and isolate a malicious node, which improves the packet delivery ratio and lowest increasing in the throughput, while reducing the success rate of the misbehaving nodes.
Бесплатно
An Epistemic Model Checking Approach to Web Service Compositions
Статья научная
Due to the dynamics of Web services, the openness and variability of Internet, and the loosely-coupled developing approach of Web services, the development and execution process of Web service compositions becomes uncertain, which imperils the trustworthy properties. In this paper we abstract Web service compositions as multi-agent systems, propose a formal model BSTS for modeling BPEL, develop and implement two translation algorithms B2S and S2I, to translate BPEL into BSTS and translate BSTS into the input language ISPL of the model checker MCMAS for multi-agent systems, respectively. The proposed method supports not only temporal properties, but also epistemic and cooperation properties, which are supported only in multi-agent systems. We implemented the prototype tool, called MCWS, for the proposed method. We modeled and verified an example of Web service compositions. The experimental results show the validity of MCWS.
Бесплатно
An Extended Research on the Blood Donor Community as a Mobile Application
Статья научная
In the developing and the least developed countries, the number of blood banks are limited and it is hard to find a blood donor with exact blood group in a crucial moment. Patients have to suffer a lot and in some cases, death is inevitable. Emergency situations like- accidents, ongoing treatments and elective surgeries create critical and immediate need for specific group of blood. In this regards, a little attention has been given on the easier availability of blood from nearest locations. In this paper, we propose a mobile phone application by which anyone will be able to look for their desired blood group at the nearest location. A large number of people is currently using smartphones running on different operating systems. The application will be developed in different platforms e.g. Android, Windows Phone or iOS, where only registered person, with willingness to donate blood will be able to access the service.
Бесплатно
An Improved Dynamic Probabilistic Packet Marking Algorithm
Статья научная
An improved dynamic probabilistic packet marking algorithm named IDPPM is presented, which not only can reduce the marking overhead of routers near the attackers, but also can locate attack source rapidly and accurately. The challenge of weakest node and weakest link is solved with the price of a little more numbers of packets to reconstruct the attack path. Theoretical analysis and NS2 simulation demonstrate the effectiveness of the algorithm.
Бесплатно
An Incentive Compatible Reputation Model for P2P Networks
Статья научная
An important challenge regarding peer's trust assessment in peer-to-peer (P2P) networks is how to cope with such issues as the fraudulent behaviors and the dishonest feedback behaviors from malicious peers, and the issue of inactive recommendations to others. However, these issues cannot be effectively addressed by the existing solutions. Thus, an incentive compatible reputation management model for P2P networks, named ICRM, is proposed to solve them. In ICRM, the metric of time zone is used to describe the time property of the transaction experience and the recommendation. Three other metrics such as the direct trust value, the recommendation trust value and the recommendation credibility, based on the metric of time zone are applied to express accurately the final trust level of a peer. Furthermore, the participating level is introduced as the metric to identify a peer's activeness degree. Theoretical analysis and simulation experiments demonstrate that, ICRM can effectively suppress the malicious behaviors such as providing unreliable services, or giving dishonest feedbacks to others in the P2P networks. What's more, it also can incent peers to offer recommendations to others more actively.
Бесплатно
An Ontology based Approach for Context-Aware Security in the Internet of Things (IoT)
Статья научная
Due to increased number of IoT devices, the marketplace is showing significant growth of sensor deployments around the world. The context involved in any IoT environment needs proper storage, processing and interpretation to get deeper insights from it. Previous research has not focussed much on context-ware security in IoT environment and has primarily relied on context-ware computing methods. In this research paper we implement logical decisions among IoT nodes in healthcare system using ontological approach. With the help of ontological method collected data is transferred between various healthcare devices to the knowledge base thereby achieving security of context like patient data by providing deeper insights, so as to generate intelligent suggested solutions. Incorporation of context-aware rules based on common experience for specific healthcare scenario is done to get implicit insight among IoT nodes. This work designs security ontology using Security Toolbox: Attacks & Countermeasures (STAC) framework that is implemented in Protégé 5. Moreover, Pellet (Incremental) reasoned is used to evaluate the ontology. Emergency ontology that can prove helpful at emergency times has also been designed. Different parameters addressed in this work are authentication, access-control, authorization and privacy using context-awareness methodology that can enable naive users make informed security decision.
Бесплатно
An Overview of Reconfigurable Antennas for Wireless Body Area Networks and Possible Future Prospects
Статья научная
The use of antennas in various fields and applications is gaining much importance because of their growing advancements and numerous facilities. Due to their vast advantages, now wearable antennas are used in fields of personal healthcare, entertainment, military and many others. For the fabrication of wearable antennas, many aspects need special consideration in order to manufacture a safe system for the user. As the applications of wireless body centric communication with antennas has a great variability, so enhancements are made in the systems by integrating reconfigurable antennas in it. These antennas work better than the single installed antennas because of their adjustable parameters thus increasing the performance of whole system. This paper provides an overview of the existing antennas and their applications, in order to better understand ways in which the limitations associated with wearable antennas could be overcome in the future. Certain design challenges which occur during the fabrication of wearable antennas like safety, cost and tolerance in addition to the recent advancements in this field are discussed. Designing a particular antenna for body area network mainly depends upon the application of the user and the place of installation. To build a review about the reconfigurable antenna for body centric communication, 15 papers from the last 6 years are consulted which fall under the domain of wearable antennas. There is still a margin of improvement in this field and better technologies will be introduced in coming years which include precision medicine.
Бесплатно
An Unconditionally Secure Authentication Code For Multi-Source Network Coding
Статья научная
In network system, network coding allows intermediate nodes to encode the received messages before forwarding them, thus network coding is vulnerable to pollution attacks. Besides, the attacks are amplified by the network coding process with the result that the whole network maybe pollutes. In this paper, we proposed a novel unconditionally secure authentication code for multi-source network coding, which is robust against pollution attacks. For the authentication scheme based on theoretic strength, it is robust against those attackers that have unlimited computational resources, and the intermediate nodes therein can verify the integrity and origin of the encoded messages received without having to decode them, and the receiver nodes can check them out and discard the messages that fail the verification. By this way, the pollution is canceled out before reaching the destinations.
Бесплатно
Статья научная
Recent advancement in microelectronics and sensor devices have led to the development of a new family of networks called Internet of things (IoT). One of the challenges of IoT is the integration of autonomous and smart devices with multiple constraints specific to the wireless sensor network (WSN) environment. Among these constraints, the most important constraint is the energy efficiency of medium access control (MAC) protocol. To solve this problem, we propose an improved protocol called clustering based load adaptive MAC (CLA-MAC) for WSNs in IoT scenario, which involves mainly traffic load balancing within each cluster to provide a tuneable trade-off between energy consumption, delay, and throughput. The proposed solution makes the MAC protocol more energy efficient by reducing competition between sensor nodes with the adoption of clustering scheme and traffic distribution, which can significantly reduce the probability of collision and idle listening. Simulation results indicate that the proposed approach performs better compared with load adaptive MAC (LA-MAC) protocol in typical IoT scenario.
Бесплатно
An improved IOT Authentication Process based on Distributed OTP and Blake2
Статья научная
The Internet of Things operates in vital areas and involves people, objects, and networks. Indeed, it ensures the interconnection and exchange of critical information that does not tolerate flaws. A successful attack on an object in one of these fields will cause fatal damage. Therefore, securing IOTs requires particular attention to the used protocols. It is essential to choose adapted protocols to the requirements of the objects and provide maximum security. Authentication is the first entry to IOTs that must be optimal and secure, without encumbering objects with limited capacities. To address this issue and to avoid concentration points, we present an improved authentication protocol based on the Blake2 hash function and the distribution of calculating OTP function. We will then evaluate, in terms of spatial and temporal complexity, the improvement brought to the IOT authentication process by the proposed process. We will prove that the use of these technics ensure a secure authentication that consumes less time and less memory.
Бесплатно
