A Survey on Industrial Internet of Things: A Cyber-Physical Systems Perspective <s> III. CONTROL SYSTEMS IN I-IOT <s> A survey on networked control systems (NCSs), published in a previous paper, is updated and extended. A simple framework and some general formulations for the study of NCSs are proposed. In addition to the survey on NCSs, the impact of NCSs on traditional large-scale system control methodologies with a related application is also reviewed. <s> BIB001 </s> A Survey on Industrial Internet of Things: A Cyber-Physical Systems Perspective <s> III. CONTROL SYSTEMS IN I-IOT <s> The aim of this paper is to review and to propose a classification of a number of decentralized, distributed and hierarchical control architectures for large scale systems. Attention is focused on the design approaches based on Model Predictive Control. For the considered architectures, the underlying rationale, the fields of application, the merits and limitations are discussed, the main references to the literature are reported and some future developments are suggested. Finally, a number of open problems is listed. <s> BIB002 </s> A Survey on Industrial Internet of Things: A Cyber-Physical Systems Perspective <s> III. CONTROL SYSTEMS IN I-IOT <s> This document provides guidance on how to secure Industrial Control Systems (ICS), including Supervisory Control and Data Acquisition (SCADA) systems, Distributed Control Systems (DCS), and other control system configurations such as Programmable Logic Controllers (PLC), while addressing their unique performance, reliability, and safety requirements. The document provides an overview of ICS and typical system topologies, identifies typical threats and vulnerabilities to these systems, and provides recommended security countermeasures to mitigate the associated risks. <s> BIB003 </s> A Survey on Industrial Internet of Things: A Cyber-Physical Systems Perspective <s> III. CONTROL SYSTEMS IN I-IOT <s> Industrial systems always prefer to reduce their operational expenses. To support such reductions, they need solutions that are capable of providing stability, fault tolerance, and flexibility. One such solution for industrial systems is cyber physical system (CPS) integration with the Internet of Things (IoT) utilizing cloud computing services. These CPSs can be considered as smart industrial systems, with their most prevalent applications in smart transportation, smart grids, smart medical and eHealthcare systems, and many more. These industrial CPSs mostly utilize supervisory control and data acquisition (SCADA) systems to control and monitor their critical infrastructure (CI). For example, WebSCADA is an application used for smart medical technologies, making improved patient monitoring and more timely decisions possible. The focus of the study presented in this paper is to highlight the security challenges that the industrial SCADA systems face in an IoT-cloud environment. Classical SCADA systems are already lacking in proper security measures; however, with the integration of complex new architectures for the future Internet based on the concepts of IoT, cloud computing, mobile wireless sensor networks, and so on, there are large issues at stakes in the security and deployment of these classical systems. Therefore, the integration of these future Internet concepts needs more research effort. This paper, along with highlighting the security challenges of these CI’s, also provides the existing best practices and recommendations for improving and maintaining security. Finally, this paper briefly describes future research directions to secure these critical CPSs and help the research community in identifying the research gaps in this regard. <s> BIB004 </s> A Survey on Industrial Internet of Things: A Cyber-Physical Systems Perspective <s> III. CONTROL SYSTEMS IN I-IOT <s> Supervisory control and data acquisition (SCADA) systems, are part of industrial control system (ICS), have been playing crucial roles in real-time industrial automation and controls. Through the evolution of 3rd generation, or networks based system, SCADA systems are connected to almost types of networks such as wired, wireless, and cellular and satellite communication, but security is still a big challenge for SCADA system while communicating within. Internet of things (IoT) is a ubiquitous platform, a new advance enhancement, for efficient SCADA system, where billions of network devices, with smart sensing capabilities, are networked over the Internet access. Deployment of smart IoT platform, SCADA system will significantly increase system efficiency, scalability, and reduce cost. Security is still a major issue for both-, as they were initially designed without any priority and requirements of security. This study modeled IoT-SCADA system and deployed a security mechanism, employing of cryptography based algorithm, which provided a secure transmission channel while each time communication occurred, between the field devices in the SCADA system. Proposed security implementation, and computed measurements analyzed as potential security building block against authentication and confidentiality attacks. <s> BIB005 </s> A Survey on Industrial Internet of Things: A Cyber-Physical Systems Perspective <s> III. CONTROL SYSTEMS IN I-IOT <s> Electrical transmission lines are generally exposed to harsh natural environment and leads to different types of failures including thundering, rain, lightning phenomena, flashover, and overheating. The Internet of Things (IoT) represents a step beyond the utilization of conventional SCADA by increasing the use of wireless technology and provides real-time data acquisition. The objective of this paper is to design an Arduino connected to different sensors for monitoring and controlling transmission system problems. These sensors include PIR (Pyroelectric Infra-Red) sensor, relay for control, and wireless sensors for conductor galloping due to the wind, meteorology, and temperature. The IoT is applied by simulating circuit with different sensors to monitor and control possible technical failures. <s> BIB006
The control systems in I-IoT environments play a crucial role in controlling and operating the critical infrastructures for factory manufacturing, power generation plants, oil and gas distribution systems, and so on. Generally speaking, the control systems can be categorized into three types: centralized control, decentralized control, and hierarchical control, based on the overall system structure, as shown in Figures 3, 4 and 5 BIB001 , BIB002 . Additionally, the network provides communication infrastructure for the data exchange between subsystems. A. CENTRALIZED CONTROL Figure 3 illustrates the structure of a centralized control system, which uses a centralized controller to monitor and control a number of subsystems. Each subsystem consists of sets of sensors and actuators, denoted as S and A, respectively. The sensors capture the operation status and condition and report the information to the centralized controller. The centralized controller sends control and command signals to the actuators in each entity in response to command and control decisions. The collection of sensing, analysis, and command transmission for all entities are carried out in the centralized controller. Supervisory Control And Data Acquisition (SCADA) is an example of a centralized control system. SCADA has been widely used to monitor and control largescale interconnected systems, such as those for water distribution, in oil, gas and electricity industries, etc. BIB003 . A typical SCADA system, as shown in Figure 6 , consists of human machine interface (HMI), SCADA servers, remote terminal units (RTUs), sensors and actuators, and others BIB004 . In more detail, the HMI enables operators to direct command to the dispersed RTUs. The RTUs are often deployed in distributed sites to perform localized processing for monitoring and control. SCADA servers conduct information collection, analysis and command dissemination. The features of SCADA (i.e., data acquisition and supervisory control) enable the centralized monitoring and control on the dispersed assets in distributed locations. Recall that the emerging IoT integrates various stateof-the-art network technologies to provide ubiquitous 78242 VOLUME 6, 2018 connections for an enormous quantity of devices in a variety of application domains. A number of representative network technologies in IoT, such as 5G, WiFi, M2M communication, and SDN, among others, can be integrated into the SCADA system to provide ubiquitous connections for large numbers of industrial devices. In this case, the integration of IoT and SCADA can improve the interoperability of industrial applications along with optimized resource allocation  . For example, Lu and Yang  presented the integration of IoT with the centralized control system to monitor the critical infrastructure of industrial applications, where they illustrated the design of I-IoT from an engineering perspective (e.g., power supply, connectivity options, hardware, software and data acquisition methodologies). In addition, Alhebshi et al. BIB006 leveraged IoT to monitor and respond to the failures of transmission lines in the smart grid. Nonetheless, the integration of IoT and traditional SCADA expose industrial control systems to additional vulnerabilities. Particular to this issue, Sajid et al. BIB004 investigated the potential exposure of the critical industrial system to security issues in the IoT-cloud environment. Possible solutions to address these security vulnerabilities were also studied from two aspects. The first is the SCADA system security (e.g., policy management, data integrity, and weak communication), and the second is the SCADA system in the IoT-cloud environment (data integrity and privacy, data logging, and authentication encryption, etc.). In addition, Shahzad et al. BIB005 leveraged the advanced encryption standard (AES) algorithm to encrypt communication and prevent authentication and confidentiality attacks on IoT-SCADA systems.