Networked Cyber-physical Systems Research Articles

An Online Optimization Approach for Control and Communication Codesign in Networked Cyber-Physical Systems

Networked cyber-physical systems (NCPS), where control and communication are closely integrated, have been envisioned to have a large number of high-impact applications. In this paper, a joint optimization framework is presented, which combines the objective of control as well as other relevant system objectives and constraints such as communication errors, delays and the limited capabilities (e.g., energy capacities) of devices. The problem is solved by an online optimization approach, which consists of a communication protocol and a simulated annealing based control algorithm. Meanwhile, by taking into account the communication cost, we optimize the control intervals by integrating two kinds of acceptances, i.e., cyber and physical acceptances, into the control algorithm. Numerical results show the effectiveness of the proposed approach.

Editorial for Special Issue on “New Technologies and Applications for Wireless Communications & Mobile Cloud Computing”

Editorial: This special issue features eight selected papers with high quality. The first article, “A Cost-Effective Methodology Applied to Videoconference Services on Hybrid Clouds” by Javier Cervino, Pedro Rodriguez, Irena Trajkovska, Fernando Escribano and Joaquin Salvachua, tackles the optimization of applications in multi-provider hybrid cloud scenarios from an economic point of view. However the approach was intended to introduce a novel solution by making maximum use of divide and rule. Also this article describes a methodology to create cost aware cloud applications that can be broken down into the three most important components in cloud infrastructures: computation, network and storage. A real videoconference system has been modified in order to evaluate this idea with both theoretical and empirical experiments. The proposed system has become a widely used as a tool in several national and European projects for e-learning and collaboration purposes. The second article, “An Efficient Dynamic Integration Middleware for Cyber-Physical Systems in Mobile Environments” by Young-Sik Jeong, Sang Oh Park and Jong Hyuk Park, proposes a cyber-physical system (CPS) middleware framework that ensures interoperability and communication between heterogeneous components in a global CPS network. A CPS is a tight integration of the system’s computational and physical elements. The CPS technology builds on the older discipline of embedded systems, and CPS applications can be found in diverse industry sectors, such as smart home, health care, and transportation. The article assume that a global CPS network that integrates different CPS networks appears in the near future. Through local and global communications, the proposed middleware makes mobile devices in different networks interoperable. The third article, “Particle Swarm Optimization with Skyline Operator for Fast Cloud-based Web Service Composition” by Shangguang Wang, Qibo Sun, Hua Zou, Fangchun Yang, proposed a fast Cloud-based web service T. Shon (*) Division of Information and Computer Engineering, College of Information Technology, Ajou University, Suwon, South Korea e-mail: taeshik.shon@gmail.com

An Efficient Dynamic Integration Middleware for Cyber-Physical Systems in Mobile Environments

Advances in information technologies have brought a wide variety of computing environments. In recent years, integrations of computational, networking, and physical elements in different environments tend to increase, so interoperability between heterogeneous computing elements has become a key area of research. A cyber-physical system (CPS) that has gained a lot of attention lately is a tight integration of the system's computational and physical elements. The CPS technology builds on the older discipline of embedded systems, and CPS applications can be found in diverse industry sectors, such as smart home, health care, and transportation. There is a high possibility that a global CPS network that integrates different CPS networks appears in the near future. This paper proposes a CPS middleware framework that ensures interoperability and communication between heterogeneous components in a global CPS network. Through local and global communications, the proposed middleware makes mobile devices in different networks interoperable. It employs Internet Protocol version 6 (IPv6) and performs protocol conversion to communicate with devices using different protocols.

A Survey on Security Issues of M2M Communications in Cyber-Physical Systems

In this paper, we present a survey of security and privacy preserving issues in M2M communications in Cyber-Physical Systems. First, we discuss the security challenges in M2M communications in wireless networks of Cyber-Physical Systems and outline the constraints, attack issues, and a set of challenges that need to be addressed for building secure Cyber-Physical Systems. Then, a secure architecture suitable for Cyber-Physical Systems is proposed to cope with these security issues. Eventually, the corresponding countermeasures to the security issues are discussed from four aspects: access control, intrusion detection, authentication and privacy preserving, respectively. Along the way we highlight the advantages and disadvantages of various existing security schemes and further compare and evaluate these schemes from each of these four aspects. We also point out the open research issues in each subarea and conclude with possible future research directions on security in Cyber-Physical Systems. It is believed that once these challenges are surmounted, applications with intrinsic security considerations will become immediately realizable.

A dynamic control middleware for cyber physical systems on an IPv6‐based global network

SUMMARYA cyber physical system (CPS) is a deeply embedded system that can be applied to home devices, medical equipment, cars, and so on. Because it is expected that a CPS system will be integrated with other CPSes designed for various areas to ultimately create a global CPS network, IPv6 is suitable for these large‐scale integrated network environments. In addition, it is important to reduce high network load for efficient device control. This paper proposes a dynamic control middleware for an efficient search and control of devices on an IPv6‐based global network from anywhere through smartphones along with a new mechanism intended to drastically reduce the number of messages that are generated for searching devices. We construct an IPv6‐based testbed using laptops and smartphones to demonstrate that this middleware can be adopted by mobile devices for dynamic remote control of home devices. Copyright © 2011 John Wiley & Sons, Ltd.

Experimental Analysis of Link Estimation Methods in Low Power Wireless Networks

Wireless sensor networks are envisioned to be an integral part of cyber-physical systems, yet wireless networks are inherently dynamic and come with various uncertainties. One such uncertainty is wireless communication itself which assumes complex spatial and temporal dynamics. For dependable and predictable performance, therefore, link estimation has become a basic element of wireless network routing. Several approaches using broadcast beacons and/or unicast MAC feedback have been proposed in the past years, but there is still no systematic characterization of the drawbacks and sources of errors in beacon-based link estimation in low-power wireless networks, which leads to ad hoc usage of beacons in routing. Using a testbed of 98 XSM motes (an enhanced version of MICA2 motes), we characterize the negative impact that link layer retransmission and traffic-induced interference have on the accuracy of beacon-based link estimation, and we show that data-driven link estimation and routing achieve higher event reliability (e.g., by up to 18.75%) and transmission efficiency (e.g., by up to a factor of 1.96) than beacon-based approaches. These findings provide solid evidence for the necessity of data-driven link estimation and demonstrate the importance of addressing the drawbacks of beacon-based link estimation when designing protocols for low-power wireless networks of cyber-physical systems.

An Efficient Cyber Physical System-Based Middleware for Interoperability among Heterogeneous Devices in Game Environment

With the recent development of IT technology, various game environments are being provided. Furthermore, many studies on interoperability among heterogeneous devices are being conducted. The cyber physical system is closely related to the embedded system and can be applied to game devices, home appliances, medical equipment, and automobiles. It is expected that a global cyber physical system network will be created through the integration of various cyber physical systems in the near future. This paper proposes a cyber physical system-based middleware for interoperability among heterogeneous devices in game environment. This middleware supports local and global communications for interoperability among game devices wherever they are. In addition, the middleware supports IPv6 to control multiple home appliances.

Computing needs time

The passage of time is essential to ensuring the repeatability and predictability of software and networks in cyber-physical systems.

Experimental investigation of subcooled liquid nitrogen impingement cooling of a silicon chip : David T. Vader, Gregory M. Chrysler, Richard C. Chu and Robert E. Simons. IEEE Transactions on Components, Packaging and Manufacturing Technology—Part A, 18 (4), 788 (1995)

Several embedded system applications are used to control physical processes thus leading to the concept of Cyber-Physical System. Sensing, computation and actuation are combined by involving a set of highly heterogeneous components, i.e., digital and analog hardware, software, energy sources, and external physical systems (e.g., a room to be heated, a mechanical component). Moreover, we see the growing use of networks to connect several sub-systems in a more efficient way; this contributes to introduce a further level of heterogeneity due to the presence of messages exchanged over communication channels. All these aspects should be taken into account in the design process to find highly optimized solutions; in particular, simulation is a key technique for their verification. However, the heterogeneity of components, together with the presence of the network, forces to adopt complex and slow co-simulation techniques to carry on the simulation of the entire system.This work aims at proposing SystemC as unified framework to model and simulate Networked Cyber-Physical Systems. Concerning the modeling of continuous-time components and a specific class of discrete-time components, the different Models of Computation provided by the Analog/Mixed-Signal (AMS) extension of SystemC are used. Regarding the network, SystemC and the SystemC Network Simulation Library are used to model communications at different abstraction levels. The approach is validated by considering a networked control system. First, the accuracy and speed of SystemC simulation is compared to Matlab/Simulink simulation. Second, different simulation alternatives are compared to co-simulation. Finally, we show that the simulation speed-up achieved by all-SystemC modeling allows to explore several design alternatives and the accurate modeling of the communication network can improve the design of the controller.