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At present, the rate control algorithm for multiview high-efficiency video coding (MV-HEVC) does not have the capability of efficient coding tree unit(CTU) layer bit allocation, and the video quality varies greatly for sequences with sudden scene changes or large motions. To overcome this limitation, this paper proposes a rate control algorithm for MV-HEVC based on scene detection. Firstly, we established ρ domain rate control model based on multi-objective optimization. Then, it uses image similarity to make reasonable bit allocation among viewpoints. If the video scene is switched, the image similarity is recalculated, and then the correlation between the weights of the interview point rates and the correlation between the viewpoints are analyzed. Finally, the frame layer rate control considers the layer B-frame and other factors in allocating the code rate, and the basic unit layer rate control adopts different quantization methods according to the content complexity of the CTU. Experimental results show that the proposed rate control algorithm can maintain good coding efficiency and decrease the average video quality variation by 25.29%.

The rapid development of the Internet of Things (IoT) concept has promoted the presence of routing protocol for low power and lossy network (RPL). Unlike traditional applications, many applications envisioned for IoT networks may have different and sometimes conflicting requirements. In this context, the underlying routing protocol requires to provide quality of service (QoS) for multipurpose IoT and is inevitable. However, the routing approach in RPL is not efficient because default objective functions (OFs) rely on a single metric, which can result in a tradeoff in routing performance, particularly for multipurpose IoT that enchant different QoS requirements in the same network. Although RPL specification allows the use of multiple metrics for parent selection, however, no specific guideline is defined for metric combinations. Besides, many studies have revealed that RPL encounters severe problems in large scale networks as it was mainly designed for low data traffic network. To address these problems, in this paper, we primarily focus on QoS differentiation by exploiting the multi-topology routing feature of the RPL standard. For this, we propose different OFs, which ensures the QoS differentiation at the network level by splitting the physical network virtually into multiple RPL Instances. Each Instance can incorporate different traffic by associating with differing OFs, and routed it through the corresponding virtual network topology. We also present a new parent selection framework based on a multi-attribute decision-making approach that addresses the single routing metric problem in RPL. The extensive simulation results verify that our multi-topology routing approach can support the QoS provisioning and is suitable for large scale networks as compared with standard RPL.

The distribution system plays an important role in the power system to meet out the power demands of the utility customer. It may lose its stability due to the influence of faults which leads to interruptions in supply to the utility customers. Therefore, the utility should take immediate necessary measures to ensure the quality of supply and restored the system to optimal that can satisfy all the constraints of the power system. This research work focuses on joined service restoration and optimization. Service restoration is done through restructuring and optimization is carried out through Stud Krill Herd Algorithm (SKHA). The distribution system optimization is achieved by reconfiguration and capacitor placement. SKHA is utilized for handling reconfiguration and optimal capacitor placement simultaneously. The effectiveness of the proposed strategy is validated by implementing two benchmark case studies namely IEEE 33 Bus Radial Distribution System (RDS) and Taiwan Power Distribution Company (TPDC) System.

Power Distribution systems are one of the most critical links between utility and utility customers. Control of power loss in distribution systems is desperately essential considering the economic aspects. Reconfiguration, Capacitor Placement, and Phase Balancing are the different methods practiced for power loss reduction. Due to the unbalanced nature of the distribution system, phase balancing is considered as the effective one amongst the above mentioned three methods. Unbalanced feeders not only increase power losses and the risk of overload situations, but they also affect power quality and electricity prices. A severely unbalanced circuit can result in excessive voltage drops on the heavy phase. Even a feeder system is intended as a balanced feeder supported the given load data, load prediction errors and unbalanced load growth can induce feeder imbalance. Phase swapping is a direct and effective way to balance a feeder in terms of phases. It has been practiced by engineers based on their previous experiences, and trial and error for phase balancing. In this paper, a phase swapping algorithm based on Stud Krill Herd Algorithm (SKHA) has been developed to minimize the phase current deviation amongst the phases. The validation of the proposed algorithm is done through two standard test cases and simulation results are compared with literature.

The primary aim of the utility must be delivering of power supply to the utility customers with the minimal cost. Therefore, it is essential to prepare the optimal load dispatch strategy for minimization of generation cost. However, with the increase in environmental consciousness and impact of global warming, the emission dispatch from the generating stations should be viewed seriously along with generation cost reduction. The joined optimization of generation cost and emission cost has been referred as Dynamic Economic and Emission Dispatch (DEED). The combined objective function is subject to power flow, generator limit and ramp rate constraints for providing better operating conditions at the generation and transmission system. Additionally, the rapid increase of Plug-in Electric Vehicles (PEV's) in power networks makes the allocation of generating units more dynamic. The allocation of generating units under the dynamic behavior of PEV's at the energy network requires a dynamic optimization procedure. This paper proposes a hybrid Fuzzy and Flower Pollination Optimization Algorithm (FFPOA) for optimal load and emission dispatching. FFPOA is used to find the optimal solution and fuzzy is used to combine both economic and emission dispatch together. In addition, the solution process addresses the presence of PEV's in the power network along with the normal electric loads. The validation of the proposed algorithm is done with two benchmark test cases.

The primary goal of distribution networks is to transfer uninterrupted power supply between utility and utility customers with greater quality. The control of real power transmission loss and maintaining the bus voltage within the permissible range are considered to measure the quality of power delivery by the utility. In recent years, strategies such as reconfiguration, capacitor placement and Distributed Energy Resources (DER) placement are practiced for improving the power delivery performance of the distribution system. Furthermore, the placement of Flexible AC Transmission System (FACTS) devices such as series and shunt controllers are also used for line and load compensation in the power system for performance enhancement. In this research work, the performance analysis of three types of the FACTS devices such as Static VAR Compensators (SVC), Thyristor Controlled Series Capacitor (TCSC) and Unified Power Flow Controller (UPFC) have been carried out with the support of hybrid Fuzzy-Flower Pollination Optimization Algorithm (FFPOA). The FPOA identifies the optimal size and location of suitable FACTS devices in a distribution system for optimizing the Total Operating Cost (TOC) and bus voltage improvement. In addition, heuristic fuzzy is integrated for the effective handling of the multi-objective problem on distribution system optimization. The efficiency of the proposed hybrid algorithm is validated with the three standard benchmark test cases.

Effect of annealing to realize high-quality $\alpha$ -Ga 2 O 3 epilayers grown by halide vapor phase epitaxy has been studied. The structural and optical properties of $\alpha$ -Ga 2 O 3 changed with changing annealing duration. In particular, for an annealing duration of 3 min, the crystal quality improved from 51 and 2757 arcsec to 28 and 1539 arcsec for (0006) and (10-14) FWHM, respectively. X-ray photoelectron spectroscopy results confirmed that the oxygen gas during annealing reacted to compensate the oxygen vacancies in the $\alpha$ -Ga 2 O 3 epilayers. These results show that the optimized thermal annealing improved the crystal quality of $\alpha$ -Ga 2 O 3 epilayers.

This paper explores mobility mining to extract relevant node and network characteristics in Delay Tolerant Networks during disaster scenarios. Through mobility analysis, this paper aims to discover location hotspots and look at mobility entropy of different node groups with different roles during a disaster. In general, this paper presents a routing scheme for DTN that aims to improve the effective delivery of messages on specific geographic locations and entities. The routing scheme incorporates Area of Interest (AoI) of nodes and calculation of encounter probability in the routing decision and proposes better message management to optimize node’s memory. Simulation results show significant advantages of the proposed scheme compared to Epidemic for geographic routing and Epidemic scheme with Angle of Deviation (AoD) in terms of delivery rate, delivery latency, and message overhead.

Current implementation of VANET-based road safety warning message and advertisement dissemination does not consider cooperation of other available helpful parties such as nearby establishments. This paper presents a communication scheme that can support both road safety warning (RSW) and advertisement dissemination that also considers the participation of an establishment-based Road Side Unit (eRSU) for message dissemination. To reduce message overhead and ensure prompt and effective delivery of RSW and advertisements, the proposed scheme utilizes an interest-area aware and destination probability of encounter metrics for vehicle to vehicle (V2V) message dissemination. The proposed work is compared with several dissemination protocols and simulation results show several significant advantages of the approach in terms of effective delivery rate, delivery time and message overhead.

We report on the monolithic integration of RGB InGaN dot-in-a-wire LEDs on a single chip. The correlated color temperature can be continuously varied in the range of 1900K to 6800K, while maintaining excellent color rendering index capability (CRI>90). Moreover, submicron scale RGB pixels were demonstrated.

A monolithic integrated photonic platform is essentially required for a broad range of applications, including optical interconnect, quantum information processing, lighting, display, and sensing. To date, however, a ubiquitous platform for photonic integration has remained elusive. While Si photonics has been extensively studied, it has several serious shortcomings [1], including optical absorption in the ultraviolet, visible and telecom wavelengths range, and lack of second order nonlinearity. Moreover, due to the indirect bandgap of Si, a practical Si-based electrically injected laser has not been possible. These critical challenges can be readily addressed by developing a GaN-based integrated photonic platform. GaN has a direct energy bandgap of 3.4 eV and can be further tuned from 6.2 eV to 0.65 eV through alloying with In and Al, which enables a broad range of active photonic devices, including light emitting diodes (LEDs), lasers, and photodetectors operating in the deep ultraviolet (UV), visible and near-infrared spectral range. GaN exhibits strong second order nonlinearity, and the χ(2) coefficient is on the same order as LiNbOs [2, 3]. GaN has excellent thermal, electrical and optoelectronic properties, and possess outstanding potential for both linear, nonlinear, and quantum optical applications. Moreover, GaN has a wide transparency window, from ∼ 0.36 μm to 13.6 μm [4]. To date, however, the extraordinary potential of GaN-based materials for integrated photonics has been severely limited by the presence of large densities of defects and dislocations in conventional GaN planar heterostructures. In this context, we propose to develop a GaN nanowire based platform for integrated nanophotonics, which can be monolithically integrated on Si and other foreign substrates and are nearly free of dislocations. We have demonstrated the epitaxy of InGaN nanostructures with controlled shape, composition, and morphology, which will serve as the building block for the emerging GaN integrated nanophotonics.

Corrections have been made to the above named paper.

This paper presents an energy-efficient scheme for wireless body area networks that utilizes two-hop strategy to forward packets to the coordinator node. It selects a forwarder node with the lowest cost function based on remaining energy and distance to the coordinator node for minimum energy consumption. The scheme includes a decision rule that ensures delivery of important packets during low energy conditions. Simulation results show that the proposed scheme performs better than other transmission schemes in terms of network lifetime, network stability, total and average residual energy and number of packets transmitted in success.

Context information utilization for routing in Delay Tolerant Networks (DTN) has received great research attention in recent years. Context information is inherent and dynamic in mobile nodes and its application improves message delivery in DTN. This paper presents a context-metric queuing method, called CEAMS for DTN that aims to optimize the delivery of message with HIGH priority by exploiting time-variant context information of a node in the network. Our approach introduces a Node Delivery Capability (NDC) metric using node's remaining energy, estimated distance to the destination and speed as metric in queuing and sorting messages in a buffer. We also design and implement the use of an energy-aware message priority transmission scheme with the proposed buffering model with admission and transmission control unit components. Our experimental results show the increase in delivery rate of HIGH priority messages and decrease in message redundancy compare to other DTN routing protocols using other queuing schemes.

An ultrahigh photocurrent (PC) signal which was about thousand times higher compared to the corresponding dark current was achieved in a two-dimensional (2D) multi-layer MoS2 field effect transistor (FET), owing to a gate-controlled MoS2/Ti/Au Schottky barrier (SB) modulation. The SBs can be enlarged for suppressing the electron drift along the channel in dark environment, and be reduced for the collection of photo-excited charge carriers in illuminating environment, providing the great potential for 2D electronic and optoelectronic applications.

Mobility model is an essential factor in evaluating routing protocols designed for Delay Tolerant Networks. The use of inappropriate mobility models for evaluating a routing protocol in DTN can significantly affect its performance and the applicability in real world. In literature, many of existing mobility models designed for their own routing protocols are somewhat inappropriate since they are not designed for all possible scenarios. In this paper, we seek to understand the effects of different mobility patterns on routing protocols developed for DTNs applied in a specific environment, and then evaluate the impact of these mobility models by varying the number of nodes in the network. This paper is mainly focused on using mobility-based models and assessing their performance in terms of encounter times, contacts per hour, delivery probability, average latency and remaining energy of nodes.

Wind energy is currently the fastest growing source of renewable energy used for electrical generation around world. Wind farms are adding a significant amount of electrical generation capacity. The increase in the number of wind farms has led to the need for more effective operation and maintenance procedures. Condition Monitoring System(CMS) can be used to aid plant owners in achieving these goals. Its aim is to provide operators with information regarding the health of their machines, which in turn, can help them improve operational efficiency. In this work, wind turbine fault detection system based on wind vs. power performance curve obtained from SCADA is studied. Considered fault detection scheme utilizes artificial neural network for training normal behavior of wind turbine system. Furthermore, In order to verify the effectiveness of the performance curve based fault detection scheme, SCADA data obtained from 850kW wind turbine system installed in Kunsan Korea are used and various simulation studies were carried out.

In this work, we propose an instantaneous rate based cooperative medium access control (MAC) protocol (termed as IrcMAC) and compare its performance gain over the existing cooperative MAC protocols under heavy load and fast fading conditions. CoopMAC I protocol, proposed in [5] which selects either direct path or relay path based on rate comparison to enhance average throughput and delay, performs worse under fading conditions due to lower direct path or relay path reliability. UtdMAC protocol, proposed in [8], performs better than CoopMAC I due to improved transmission reliability provided by the back up relay path, however, it uses relay path only as a secondary backup path. Our proposed IrcMAC protocol makes use of channel coherence time and estimates instantaneous signal-to-noise ratio (snr(t)) of source-to-relay, relay-to-destination and source-to-destination links; to reliably select between relay path or direct path for enhanced throughput and delay performances. Simulation results clearly show that IrcMAC significantly outperforms the existing CoopMAC I and the UtdMAC protocols in wireless ad hoc network.

In this paper, we propose hybrid cooperative medium access control (MAC) protocol that adaptively uses single relay path or two relay paths for enhanced throughput and delay performance under fast Rayleigh fading conditions. The proposed protocol, termed as 2rcMAC, invokes two best relay (cooperating) paths for improved spatial diversity that offer higher transmission rate compared to the direct transmission path. It transmits through primary relay path for higher throughput performance and uses secondary relay path for reliable backup transmission. In case, only one best relay path (with higher rate than the direct transmission path) is available, the 2rcMAC protocol transmits directly to the destination node and invokes the secondary relay path for backup transmission only. Furthermore, handshaking and single bit feedback in 2rcMAC protocol resolve contentions among relay nodes in close proximity at the time, and further provide source node with rate information on source-to-destination, source-to-relay and relay-to-destination links. Simulation results clearly show average throughput improvement of 7% and 25% and average delay improvement of 94.8% and 98.9% compared to UtdMAC and CoopMAC I, respectively [4], [5], [7].

Evergrowing consumer demand for wireless connectivity is opening a new paradigm of communications, “Aeronautical Data Networks (ADN)”. The desire is to provide high throughput and cost effective data network not only for an aeronautical applications, but also for terrestrial networks by using aeronautical platforms as a backbone. An aeronautical station (AS) could be a commercial plane, a helicopter, or any other low orbit station, i.e., Unmanned Air Vehicle, High Altitude Platforms. In this paper, we study an aeronautical broadband wireless access scheme to provide throughput and delay analysis for ADN. First, a simple topology of ADN is presented as a mobile ad-hoc network (MANET). A two-hop network model is considered where each packet makes two hops, one from the source AS to a relay AS and one from the relay AS to the destination AS. Then, based on the method of finding the maximum number of concurrent successful transmissions, the ADN throughput upper bound is obtained. Closed-form end-to-end delay expression is also derived, to provide a general ADN system performance in terms of throughput and delay. Numerical results are presented, which show the alignment with our theoretical analysis.

An electrically switchable graphene photo-sensor (SGPS) is proposed for multiple functional applications. SGPS is a dual-gate thin-film transistor with a graphene channel and a phase-change chalcogenide (GeSbTe) gate filter. This gate filter is switchable between the amorphous (optically transparent) and crystalline (optically non-transparent) phases by applying the gate biases. When the gate filter is switched to the amorphous/crystalline (a/c) phases, the SGPS will/not yield photo-current (I pc ) under a constant light source. By detecting the presence of I pc , two data states can be read out so as to accomplish non-volatile data storage. SGPS can present a switching speed of ∼50 ns between the a/c phases of GeSbTe and a data access speed as fast as 10 ns. SGPS shows very good 10-year data retention at 85°C and good endurance of >106 switching cycles between the a/c phases of the GeSbTe gate filter.

A cooperative ratio-based scheduling scheme with minimal signaling to enhance network throughput and fairness in wireless ad hoc network is presented in this paper. Throughput and fairness maximization problem in a finite horizon (short term) is formulated as a novel multi-window optimization problem. Through analysis users' thresholds are shown to be time variant to achieve throughput maximization with fairness in each window. Simulation results clearly show that compared with non decision-based strategy, ratio-based scheme achieves within 1.6 % of the maximum throughput value and is scalable in terms of the number of nodes. Fairness performance is marginally better than non decision-based strategy.

Potential well engineering is proposed for NAND Flash memory. With a variable (∼2nm–4.3nm) tunnel barrier, the engineered well (EW) enhances tunneling of carriers during program/erase (P/E) to result in fast P/E, while it suppresses charge loss under the retention mode to result in good data retention. The EWalso improves endurance, as it is insensitive to the P/E stress induced tunnel barrier degradation. The EW demonstrated in this work is formed by partial oxidation of TiN at the interfaces of the SiO 2 /TiN/SiO 2 stack during rapid thermal process (RTP), and its band profile is characterized by XPS, TEM, internal photoemission (IPE), XRD, and band simulation. The memory devices with an EW show promising performances in fast program (≪µs), low-voltage operation (6–8MV/cm), good 10-year data retention at 125°C, and excellent endurance (≫107 P/E cycles).

In a resource-limited wireless communication environment, various approaches to meet the ever growing application requirements in an efficient and transparent manner, are being researched and developed. Amongst many approaches, cross layer technique is by far one of the significant contributions that has undoubtedly revolutionized the way conventional layered architecture is perceived. In this paper, we propose a Cross Layer Framework based on vertical layer architecture. The primary contribution of this paper is the functional architecture of the vertical layer which is primarily responsible for cross layer interaction management and optimization. The second contribution is the use of optimization cycle that comprises awareness parameters collection, mapping, classification and the analysis phases. The third contribution of the paper is the decomposition of the parameters into local and global network perspective for opportunistic optimization. We have shown through simulations how parameters' variations can represent local and global views of the network and how we can set local and global thresholds to perform opportunistic optimization. Finally, we conclude and highlight future challenges associated with the proposed framework.

Ad hoc wireless networks operate without any infrastructure where a node can be a source and a router at the same time. This indispensably requires high throughput and low delay performance throughout the wireless network coverage span, particularly under heavy traffic conditions. Recent research on using multiple antennas in beam-forming or multiplexing modes over a wireless channel has shown promising results in terms of high throughput and low delay. Directional antennas have shown to increase spatial reuse by allowing multiple transmitters and receivers to communicate using directional beams as long as they do not significantly interfere with each other. However, directional antenna performance asymptotically approaches the omni-directional performance in a high density ad hoc network. Simulation results in QualNet validate that average throughput and packet corruption ratio of directional antenna approach omni-directional performance.

In video data transmission, a subsampling technique is used to reduce the number of transmitted frames. This paper presents a new technique to improve the performance of video interpolation by controlling the subsampling rate of a video sequence. Subsampling is determined by the motion complexity of a frame. In the simulation results, we find that the picture quality fluctuation is reduced.