Application Layer Multicast Model with Low Delay and High Stability

As an alternative of Internet protocol(IP)multicast,application layer multicast(ALM)is widely used with the advantage of simplicity and flexibility.However,the existing problems of large transmission delay and poor stability limit the application and development.In this article,to solve these problems,an ALM model based on node potential(NP)and topological index(TI)is proposed.The proposed model considers the factors of node capability and node distance in constructing and maintaining multicast tree to reduce transmission delay and increase stability,and thus it improves the application level in real-time multimedia multicast.The computer simulations prove that the proposed model reduces the ALM transmission delay,increases multicast tree stability effectively,and improves the ALM performance,and therefore it is suitable to apply in large-scale real-time multimedia environment.

Architecture design and demand analysis on application layer of standard system for ubiquitous power Internet of Things

The ubiquitous power Internet of Things(UPIoT)is an intelligent service system with comprehensive state perception,efficient processing,and flexible application of information.It focuses on each link of the power system and makes full use of the mobile internet,artificial intelligence,and other advanced information and communication technologies in order to realize the inter-human interaction of all things in all links of the power system.This article systematically presents to the national and international organizations and agencies in charge of UPIoT layer standardization the status quo of the research on the Internet of Things(IoT)-related industry standards system.It briefly describes the generic standard classification methods,layered architecture,conceptual model,and system tables in the UPIoT application layer.Based on the principles of inheritance,innovation,and practicability,this study divides the application layer into customer service,power grid operation,integrated energy,and enterprise operation,emerging business and analyzes the standard requirements of these five fields.This study also proposes a standard plan.Finally,it summarizes the research report and provides suggestions for a follow-up work.

Survey on recent advances in IoT application layer protocols and machine learning scope for research directions

The Internet of Things(IoT)has been growing over the past few years due to its flexibility and ease of use in real-time applications.The IoT's foremost task is ensuring that there is proper communication among different types of applications and devices,and that the application layer protocols fulfill this necessity.However,as the number of applications grows,it is necessary to modify or enhance the application layer protocols according to specific IoT applications,allowing specific issues to be addressed,such as dynamic adaption to network conditions and interoperability.Recently,several IoT application layer protocols have been enhanced and modified according to application requirements.However,no existing survey articles focus on these protocols.In this article,we survey traditional and recent advances in IoT application layer protocols,as well as relevant real-time applications and their adapted application layer protocols for improving performance.As changing the nature of protocols for each application is unrealistic,machine learning offers means of making protocols intelligent and is able to adapt dynamically.In this context,we focus on providing open challenges to drive IoT application layer protocols in such a direction.

Application layer multicast routing solution based on genetic algorithms

Application layer multicast routing is a multiobjective optimization problem.Three routing constraints,tree’s cost,tree’s balance and network layer load distribution are analyzed in this paper.The three fitness functions are used to evaluate a multicast tree on the three indexes respectively and one general fitness function is generated.A novel approach based on genetic algorithms is proposed.Numerical simulations show that,compared with geometrical routing rules,the proposed algorithm improve all three indexes,especially on cost and network layer load distribution indexes.

THE APPLICATION OF DYNAMICSCHLIEREN-PHOTON CORRELATIONTECHNIQUE TO A SUPERSONIC SHEAR LAYER

By applying the dynamic schlieren-photon correlation technique to a two dimensional separated supersonic shear layer, the convection velocity of large eddies inside the shear layer and the frequency of the self-sustaining oscillation of the shear layer induced by the shedding of large eddies have been obtained. The distribution of the turbulence intensity inside the shear layer can also be estimated. It is shown that the method has its promising potentials in the measurement of high speed complex flows.

Material manufacturing from atomic layer

Atomic scale engineering of materials and interfaces has become increasingly important in material manufacturing.Atomic layer deposition(ALD)is a technology that can offer many unique properties to achieve atomic-scale material manufacturing controllability.Herein,we discuss this ALD technology for its applications,attributes,technology status and challenges.We envision that the ALD technology will continue making significant contributions to various industries and technologies in the coming years.

A survey on communication protocols and performance evaluations for Internet of Things

The Internet of Things (IoT) is a large-scale network of devices capable of sensing, data processing, and communicating with each other through different communication protocols. In today's technology ecosystem, IoT interacts with many application areas such as smart city, smart building, security, traffic, remote monitoring, health, energy, disaster, agriculture, industry. The IoT network in these scenarios comprises tiny devices, gateways, and cloud platforms. An IoT network is able to keep these fundamental components in transmission under many conditions with lightweight communication protocols taking into account the limited hardware features (memory, processor, energy, etc.) of tiny devices. These lightweight communication protocols affect the network traffic, reliability, bandwidth, and energy consumption of the IoT application. Therefore, determining the most proper communication protocol for application developers emerges as an important engineering problem. This paper presents a straightforward overview of the lightweight communication protocols, technological advancements in application layer for the IoT ecosystem. The survey then analyzes various recent lightweight communication protocols and reviews their strengths and limitations. In addition, the paper explains the experimental comparison of Constrained Applications Protocol (CoAP), Message Queuing Telemetry (MQTT), and WebSocket protocols, more convenient for tiny IoT devices. Finally, we discuss future research directions of communication protocols for IoT.

An ALM Model for Streaming Media Service in P2P-SIP Network

Application layer multicast (ALM) has been widely applied in Internet, as a substitute for IP multicast. However, it causes network load to increase because it adopts unicast in data transmission, which limits the application. In this article, in order to improve the ALM performance in P2P-SIP network, an ALM model was proposed which reduced network load via merging messages in concast mode. Finally network simulations prove that this model has better benefit on single node load and average network load. Therefore, it is suitable for streaming media service in P2P-SIP Network.

Thin layer gas electrode and its application to measurement of dissolved oxygen

A novel thin layer cell equipped with thin layer gas electrode(TLGE)was studied as electrochemical gas sensor for the measurement of dissolved oxygen in water or aqueous solutions. The working electrode(TLGE)is a hydrophohic gas diffusing electrode placed between the cell electrolyte and the solution to be tested.The hydrophobic pores in TLGE serve as a gas chamber. After the sampling period,in which the partial pressure of dissolved oxygen in test solution becomes in equilibrium with that in the gas chamber,the TLGE is polarized with square wave or linear potential signal.Then the Faradaic charge (Q) consumed in depletion of the oxygen contained in pores of TLGE is measured.The main merits of this system are good linearity between the partial pressure of dissolved oxygen in test solution and Q,low zero-reading,negligible liquid-gas difference,con- venient calibration and very low temperature coefficient(ca.0.5%/℃).This technique can also be applied to the measurement of oxygen partial pressure in gas phases.

Streaming Media over a Color Overlay Based on Forward Error Correction Technique

The number of clients that receive high-quality streaming video from a source is greatly limited by the application requirements, such as the high bandwidth and reliability. In this work, a method was de-veloped to construct a color overlay, which enables clients to receive data across multiple paths, based on the forward error correction technique. The color overlay enlarges system capacity by reducing the bottle-necks and extending the bandwidth, improves reliability against node failure, and is more resilient to fluctua-tions of network metrics. A light-weight protocol for building the overlay is also presented. Extensive simula-tions were conducted and the results clearly support the claimed advantages.