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The Software Defined Network (SDN) provides higher programmable functionality for network configuration and management dynamically. Moreover, SDN introduces a centralized management approach by dividing the network into control and data planes. In this paper, we introduce a deep learning enabled intrusion detection and prevention system (DL-IDPS) to prevent secure shell (SSH) brute-force attacks and distributed denial-of-service (DDoS) attacks in SDN. The packet length in SDN switch has been collected as a sequence for deep learning models to identify anomalous and malicious packets. Four deep learning models, including Multilayer Perceptron (MLP), Convolutional Neural Network (CNN), Long Short-Term Memory (LSTM) and Stacked Auto-encoder (SAE), are implemented and compared for the proposed DL-IDPS. The experimental results show that the proposed MLP based DL-IDPS has the highest accuracy which can achieve nearly 99% and 100% accuracy to prevent SSH Brute-force and DDoS attacks, respectively.

Many industrial wireless sensor networks deploy the IEEE 802.15.4-2015 standard with low power consumption and the Internet networking capabilities. The time-slotted channel hopping (TSCH) is an amendment to the medium access control protocol defined by the IEEE 802.15.4 standard. Furthermore, the Internet engineering task force (IETF) defines an architecture for IPv6 over the TSCH mode of IEEE 802.15.4 (6TiSCH) to provide deterministic properties on wireless sensor networks. The TSCH leverages the scheduled time slot to achieve low power operation and frequency hopping to combat external interference and multi-path fading. Although TSCH provides the channel hopping mechanism to increase transmission reliability, it is still susceptible to periodic interference for the specific frequency. In this research, we focus on the issue of random channel hopping in the error-prone wireless channel condition and the scheduling for different service requirements. We propose a priority-based scheduling using best channel (P-SBC) mechanism for periodic sensing data and emergency packets transmission in 6TiSCH networks. The simulation results show that the proposed P-SBC achieves higher reliability with significantly lower end-to-end latency for emergency packets transmission as compared to TSCH standard.

The routing protocol for low power and lossy network (RPL), constructed according to the objective function (OF), is the standard for routing selection in low power and lossy networks (LLNs). Most schemes utilise the expected transmission count (ETX) as the routing metric for the next hop. Designing effective and efficient routing protocols in LLNs require the mechanism to meet the criteria of different applications or services. In this paper, we propose a service-aware OF with quality of service (SOF-QoS) mechanism which integrates received signal strength indicator (RSSI), energy consumption, and hop count metrics into RPL OF for path selection according to different services, such as normal data, video packets and emergency messages transmission in LLNs. The proposed SOF-QoS mechanism defines various weights with fuzzy logic for the next routing selection in response to each service. We conduct the simulation under different network topologies with static and mobile scenarios to analyse the performance of the proposed SOF-QoS mechanism and compare them with the traditional RPL schemes. The simulation result shows that our proposed SOF-QoS mechanism provides relatively better or superior performance with reliability than traditional ones for different services.

In recent years, software defined networking (SDN) has become a novel network architecture and design by employing manageable software between the control and data planes. Many SDN-based intrusion detection systems (IDS) have been proposed in recent researches. On the other hand, deep learning has emerged as an explosive growth in research and industry. The application of deep learning on IDS has been studied in many security-critical scenarios. However, some reports has indicated the vulnerability of adversarial attacks on deep learning IDS system with intentional perturbation injection or manipulation. It is important for the empowered IDS system employing deep learning to be responsible for not leading misclassification. Therefore, exploring the impact on the adversarial attacks over SDN networks or security-critical scenarios applying deep learning is an important step to confront such urgent issues. In this paper, we will conduct the SDN-based experiments on adversarial attacks for deep learning detecting system. We propose a novel class of adversarial attacks that exploits the vulnerability of the deep learning classifiers in SDN environment. Three typical deep learning models combining with four different adversarial testing will be conducted in the simulation for complete analysis.

The technology of Internet of Things is gradually maturing. IoT has applied in many fields and extended to industrial networks. Thus, the IETF has proposed 6TiSCH (IPv6 over the TSCH mode of IEEE 802.15.4e) to establish the link between Internet and IWSNs (Industrial Wireless Sensor Networks). The main purpose of this research is to enhance the performance of Multi-hop 6TiSCH network by using the proposed Priority-based Fast Forward Scheduling Function (PFFSF). According to the simulation results, the proposed PFFSF has lower end-to-end transmission delay and higher throughput then the original 6TiSCH SF0 mechanism.

The recent IEEE 802.15.4-2015 standard proposes a number of Medium Access Control (MAC) layer protocols for low-power and lossy networks. The Timeslotted Channel Hopping (TSCH) is one of the proposed MAC operation modes, which take the advantage of channel hopping to make the transmissions more reliable and deterministic. In TSCH, slotframe is sliced into a timeslots and random channel hopping is used to mitigate the effects of co-channel interference and multipath fading. In this paper, we focus on the issue of random channel hopping in the error-prone wireless channel condition. In this research, a QoS Channel Allocation Scheme (QCAS) is proposed to enhance the reliability of emergency packet transmission in 6TiSCH networks. Based on our simulation results, we have observed that the proposed QCAS can achieve higher reliability of transmission over selected channel to provide higher throughput and higher delivery ratio than the original TSCH.

Wireless multimedia sensing network, used to transmit multimedia files over zigbee wireless communication, faces a big challenge in terms of transmission bandwidth and node lifetime. In this paper, we will implement the testbed of 6LoWPAN transmission for video service. We used Contiki OS to implement the wireless zigbee Zigduino nodes. We first simulated the packet loss of video transmission to optimize the packet loss recovery mechanism. Then we conducted the testbed to analyze the performance and feasibility of the wireless zigbee communication for video transmission.

In recent years, within large cities with a high population density, traffic congestion has become more and more serious, resulting in increased emissions of vehicles and reducing the efficiency of urban operations. Many factors have caused traffic congestion, such as insufficient road capacity, high vehicle density, poor urban traffic planning and inconsistent traffic light cycle configuration. Among these factors, the problems of traffic light cycle configuration are the focal points of this paper. If traffic lights can adjust the cycle dynamically with traffic data, it will reduce degrees of traffic congestion significantly. Therefore, a modified mechanism based on Q-Learning to optimize traffic light cycle configuration is proposed to obtain lower average vehicle delay time, while keeping significantly fewer processing steps. The experimental results will show that the number of processing steps of this proposed mechanism is 11.76 times fewer than that of the exhaustive search scheme, and also that the average vehicle delay is only slightly lower than that of the exhaustive search scheme by 5.4%. Therefore the proposed modified Q-learning mechanism will be capable of reducing the degrees of traffic congestions effectively by minimizing processing steps.

6LoWPAN technology has attracted extensive attention recently. It is because 6LoWPAN is one of Internet of Things standard and it adapts to IPv6 protocol stack over low-rate wireless personal area network, such as IEEE 802.15.4. One view is that IP architecture is not suitable for low-rate wireless personal area network. It is a challenge to implement the IPv6 protocol stack into IEEE 802.15.4 devices due to that the size of IPv6 packet is much larger than the maximum packet size of IEEE 802.15.4 in data link layer. In order to solve this problem, 6LoWPAN provides header compression to reduce the transmission overhead for IP packets. In addition, two selected routing schemes, mesh-under and route-over routing schemes, are also proposed in 6LoWPAN to forward IP fragmentations under IEEE 802.15.4 radio link. The distinction is based on which layer of the 6LoWPAN protocol stack is in charge of routing decisions. In route-over routing scheme, the routing distinction is taken at the network layer and, in mesh-under, is taken by the adaptation layer. Thus, the goal of this research is to understand the performance of two routing schemes in 6LoWPAN under error-prone channel condition.

Voice over Internet protocol (VoIP) has been a prevalent multimedia service nowadays. It allows us to transmit voice data over IP networks. However, quality of service (QoS) is a major challenge to VoIP services. It must provide similar quality to traditional public switched telephone network or cellular phone services. Therefore, QoS related protocols have become important for real-time applications. Multi-protocol label switch (MPLS) is one of the important techniques to improve the network performance from QoS point of view. It employs label swapping to speed up packet forwarding. However, when a large number of users utilize VoIP services, the network congestion issue still exists. It causes delay, jitter and packet loss that affect VoIP QoS. In this paper, we propose a QoS-aware path switching strategy by using stream control transmission protocol (SCTP) in MPLS network to improve the VoIP traffic. This was done by employing SCTP selective acknowledgment mechanism to report the transmission parameters of primary path and to determine the criteria to switch to backup path. Simulation results show significant improvement in VoIP QoS.

Advances of the identifying, sensing, and communicating technologies make the applications of Internet of Things (IoT) possible. Among others, the ubiquitous deployment of wireless sensor networks (WSNs) is regarded as one of the most significant forces in the IoT. Great progress in micro-electro-mechanical systems and wireless communications make the applications of WSNs more and more accessible. The limited battery power of the sensor node is vitally precious. Therefore, it is important to promote the energy efficiency to stretch the lifetime of the WSNs. In this paper, a low-power data transmission protocol, which includes a dual-frequency model, local synchronization, and channel reservation, is proposed. The results of numerical analyses and simulations show that the proposed protocol presents better energy efficiency without sacrificing end-to-end latency of data transmission in WSNs.

In this paper we design and implement the pseudo session initiation protocol (p-SIP) server embedded in each mobile node to provide the ad-hoc voice over Internet protocol (VoIP) services. The implemented p-SIP server, being compatible with common VoIP user agents, integrates the standard SIP protocol with SIP presence to handle SIP signaling and discovery mechanism in the ad-hoc VoIP networks. The ad-hoc VoIP signaling and voice traffic performances are analyzed using E-model R rating value for up to six hops in the implemented test-bed. We also conduct the interference experiments to imitate the practical ad-hoc VoIP environment. The analyzed results demonstrate the realization of ad-hoc VoIP services by using p-SIP server.

It is an important issue to provide the reliability as well as to balance the traffic load for the multihomed networks. In this paper, we deal with two most important factors, traffic load balancing and redundancy. The assigned weight for each link is dynamically computed according to the arrival and service rates via arrival rate dependent (ARD). By employing the adaptive-ARD (A-ARD) mechanism, the network performance in terms of average waiting time was further improved. The simulation result showed that more than 20% performance improvement was achieved by comparing A-ARD to RR, WRR and ARD with arrival rate 80 packets per second. Through the proposed redundancy scheme of A-ARD, the reliability of the packet transmission was fulfilled.

Thin films of BaTiO3 were deposited on single-crystal Si using rf magentron sputtering. Different microstructures resulted from varying the substrate temperature during sputtering or from post-annealing after film deposition. High trap and surface state densities at the interface between BaTiO3 and were found for the films deposited at room temperature even though such showed a relatively low leakage current and a high breakdown voltage. These surface states or traps, nevertheless, could be partially annealed out of the film a temperature around 450°C. High deposition temperatures above 600°C introduced unrecoverable surface states at the interface. BaTiO3 thin films were deposited at a substrate temperature in the range 450-500°C gave the performance in terms of their electrical and interface properties. BaTiO3 thin-film capacitors with a configuration of Au/BaTiO3/p-Si/Al, fabricated with optimized BaTiO3 thin-film deposition conditions, showed a value of the dielectric constant near 30, a leak...

Ferroelectric PbZr x Ti 1− x O 3 (PZT) thin films have been deposited on Pt-coated Si substrates by using r.f. magnetron sputtering. The optimized processing condition to obtain proper stoichiometric PZT, the desired ferroelectric perovskite phase, and better dielectric properties was demonstrated using a PZT target with Pb/(Zr + Ti) ratio of 1.2 and depositing at 350 °C, followed by thermal treatment at 620 °C for 30 min. The structural and electrical properties of the PZT layer were further improved by fabricating a novel multilayer structure which combined the PZT with the nanolayer BaTiO 3 . The leakage current density was reduced from 2 × 10 −7 A cm −2 for the single layer structure to 2 × 10 −9 A cm −2 for the multilayer structure at a field of 4 × 10 5 V cm −1 , while maintaining the high relative effective dielectric constant of 442. The relative dielectric constant of the PZT film in the multilayer structure was calculated to be about 880.

6LoWPAN is one of Internet of Things standard, which allows IPv6 over the low-rate wireless personal area networks. All sensor nodes have their own IPv6 address to connect to Internet. Therefore, the challenge of implementing secure communication in the Internet of Things must be addressed. There are various attack in 6LoWPAN, such as Denial-of-service, wormhole and selective forwarding attack methods. And the Dos attack method is one of the major attacks in WSN and 6LoWPAN. The sensor node’s energy will be exhausted by these attacks due to the battery power limitation. For this reason, security has become more important in 6LoWPAN. In this paper, we proposed a lightweight intrusion detection model based on analysis of node’s consumed in 6LowPAN. The 6LoWPAN energy consumption models for mesh-under and route-over routing schemes are also concerned in this paper. The sensor nodes with irregular energy consumptions are identified as malicious attackers. Our simulation results show the proposed intrusion detection system provides the method to accurately and effectively recognize malicious attacks.

The wireless sensor network (WSN) technology has been one of the most active research topics in the last several years. Besides sensing the environmental or physical data, there has been a growing need on supporting voice communication, particularly under emergency conditions, in WSNs. In this paper, we will conduct the implementation of voice codec on embedded system using multi-hopping ZigBee communication. The implementation issues, in terms of codec and transmission rate-dependence consideration, as well as the voice quality with multi-hopping are analyzed and evaluated for the designed test-bed.