Centralized Control Architecture Research Articles

Formal specification and verification of a distributed fault localization, isolation and supply restoration algorithm

Distributed fault localization, isolation and supply restoration (FLISR) algorithm only uses local topology information to improve system reliability in electric power enterprises. It has better adaptability than traditional centralized control architecture. To verify the correctness and reliabilit y of the distributed FLISR algorithm which applied to complex distribution network is very important in the operation of distribution network. A formal method for the specification and verification of the distributed FLISR algorithm which uses linear temporal logic (LTL) language is presented in this paper. In addition, the correctness of the algorithm in interference-free situation and the security of the algorithm in some uncertain interference such as switch action failure, communication failure and other confounding factors are proved mathematically.

Challenges: From Standards to Implementation for Industrial Wireless Sensor Networks

Despite the fact that a number of research efforts in the area of Industrial Wireless Sensor Networks (IWSNs) exist, there is a lack of really practical IWSN implementations, deployments, and in-field applications. This paper presents the design and implementation of an IWSN for welder machine systems, called WirelessCAN which is based on WirelessHART to replace wired CAN fieldbus. Although the implementation and challenges are application-specific, we believe that the problems we encountered will be faced by many IWSN designers. In this paper, selected challenges exposed in our implementation and the potential solutions are introduced, which have not been addressed previously. Specifically, communication resource constraint, real-time rescheduling, integrated knowledge for IWSN applications, centralized control architecture, reliable and immediate message delivery for human and equipment safety, and differential QoS requirements are discussed in detail and in depth. The goal of this paper is to make the design and implementation of IWSNs more efficient and applicable.

Energy storage requirements of dc microgrids with high penetration renewables under droop control

Energy storage is a important design component in microgrids with high penetration renewable sources to maintain the system because of the highly variable and sometimes stochastic nature of the sources. Storage devices can be distributed close to the sources and/or at the microgrid bus. In addition, storage requirements can be minimized with a centralized control architecture, but this creates a single point of failure. Distributed droop control enables a completely decentralized architecture but, the energy storage optimization becomes more difficult. Our paper presents an approach to droop control that enables the local and bus storage requirements to be determined. Given a priori knowledge of the design structure of a microgrid and the basic cycles of the renewable sources, we found that the droop settings of the sources are such that they minimize both the bus voltage variations and overall energy storage capacity required in the system. This approach can be used in the design phase of a microgrid with a decentralized control structure to determine appropriate droop settings as well as the sizing of energy storage devices.

Scalable Centralized Control Architecture of Virtual Switch on Large-Scale Network

Router virtualization is becoming more common as a method that uses network (NW) equipment effectively and robustly similar to server virtualization. Edge routers, which are gateways of core NWs, should be virtualized because they have many functions and resources just as servers do. To virtualize edge routers, a metro NW, which is a wide area layer-2 NW connecting each user's residential gateway to edge routers, must trace dynamic edge router re-allocation by changing the route of each Ethernet flow. Therefore, we propose a scalable centralized control architecture of a virtual layer-2 switch on a metro NW to trace virtual router re-allocation and use metro NW equipment effectively. The proposed scalable control architecture improves the centralized route control performance by processing in parallel on a flow-by-flow basis taking into account route information even in the worst case where edge routers fail. In addition, the architecture can equalize the load among parallel processes dynamically by using two proposed load re-allocation methods to increase the route control performance stably while minimizing the amount of resources for the control. We evaluate the scalability of the proposed architecture through theoretical analysis and experiments on a prototype and show that the proposed architecture increases the number of flows accommodated in a metro NW. Moreover, we evaluate the load re-allocation methods through simulation and show that they can evenly distribute the load among parallel processes. Finally, we show that the proposed architecture can be applied to not only large-scale metro NWs but also to data center NWs, which have recently become an important type of large-scale layer-2 NW.

Time-sensitive software-defined networking (Ts-SDN) control architecture for flexi-grid optical networks with data center application

Data center interconnected by flexi-grid optical networks is a promising scenario to meet the high burstiness and high bandwidth requirement of data center application, because flexi-grid optical networks can allocate spectral resources for applications in a dynamic, tunable and efficient control manner. Meanwhile, as centralized control architecture, the software-defined networking (SDN) enabled by OpenFlow protocol can provide maximum flexibility for the networks and make a unified control over various resources for the joint optimization of data center and network resources. Time factor is firstly introduced into SDN-based control architecture for flexi-grid optical networks supporting data center application. A traffic model considering time factor is proposed, and a requirement parameter, i.e., bandwidth-period product is adopted for the service requirement measurement. Then, time-sensitive software-defined networking (Ts-SDN)-based control architecture is designed with OpenFlow protocol extension. A novel deadline-driven PCE algorithm is proposed for the deadline-driven service under Ts-SDN-based control architecture, which can complete data center selection, path computation and bandwidth resource allocation. Finally, simulation results shows that our proposed Ts-SDN control architecture and deadline-driven PCE algorithm can improve the application and network performance to a large extent in blocking probability.

Critical-path-aware high-level synthesis with distributed controller for fast timing closure

Centralized controllers commonly used in high-level synthesis often require long wires and cause high load capacitance, and that is why critical paths typically occur on paths from controllers to data registers instead of paths from data registers to data registers. However, conventional high-level synthesis has focused on delays within a datapath, making it difficult to solve the timing closure problem during physical synthesis. This article presents hardware architecture with a distributed controller, which makes the timing closure problem much easier. A novel critical-path-aware high-level synthesis flow is also presented for synthesizing such hardware through datapath partitioning, register binding, and controller optimization. We explore the design space related to the number of partitions, which is an important design parameter for target architecture. According to our experiments, the proposed approach reduces the critical path delay excluding FUs by 29.3% and that including FUs by 10.0%, with 2.2% area overhead on average compared to centralized controller architecture.

Distributed Control Architecture for Wireless Sensor Networks Using IEC 61499 Function Blocks for Industrial Automation

Wireless Sensor Networks (WSN) technology is rapidly becoming a feasible solution for monitoring and control at the lowest level of manufacturing automation systems. This paper presents a distributed approach for modeling WSN for applications of intelligent manufacturing automation and control. The proposed approach uses IEC 61499 function blocks, which is a new industry standard in the context of manufacturing automation. The distributed modeling of WSN through the function blocks provides flexibility and scalability to the low-level monitoring and control of the manufacturing systems, which are two important challenges in today's conventional manufacturing control systems. The proposed model is a replacement of the conventional centralized control architecture, where local processing is performed rather than having a central control unit.

OVERVIEW OF WIRELESS NETWORK CONTROL PROTOCOL IN SMART PHONE DEVICES

The computer network connection without wire or any cable is referring as wireless network. These wireless local area networks are popular for its worldwide applications. It has covered wide scale wireless local area network. The large scale systems to all applicable areas make large numbers of wireless termination and covering very much area. To reduce the complexity associated with server management, Information Technology organizations begins the process of centralizing servers. It used with architecture principles of centralized management requirement for network to scale, network architecture needs to be able to support enhanced services in addition to just raw connectivity, distributed processing is required both for scalability ability and services, network support continuously increase the level of throughputs etc. Wireless LAN product architectures have evolved from single autonomous access points to systems, consisting of a centralized Access Controller and Wireless Termination Points. The basic goal of centralized control architectures is to move access control, including user authentication and authorization, mobility & radio management, from one access point to centralized controller. The Wireless network Control Protocol allows for access and control of large-scale wireless local area networks. It can allows management of these networks, Control and Provisioning of Wireless Access Points In computer networking, a wireless access point is a device that allows wireless devices to connect to wired network using Wi-Fi, Bluetooth or related standards. The WAP usually connects to a router via a wired network, and can relay data between the wireless devices such as computers or printers and wired devices on the network.

OVERVIEW OF WIRELESS NETWORK CONTROL PROTOCOL IN SMART PHONE DEVICES

The computer network connection without wire or any cable is referring as wireless network. These wireless local area networks are popular for its worldwide applications. It has covered wide scale wireless local area network. The large scale systems to all applicable areas make large numbers of wireless termination and covering very much area. To reduce the complexity associated with server management, Information Technology organizations begins the process of centralizing servers. It used with architecture principles of centralized management requirement for network to scale, network architecture needs to be able to support enhanced services in addition to just raw connectivity, distributed processing is required both for scalability ability and services, network support continuously increase the level of throughputs etc. Wireless LAN product architectures have evolved from single autonomous access points to systems, consisting of a centralized Access Controller and Wireless Termination Points. The basic goal of centralized control architectures is to move access control, including user authentication and authorization, mobility & radio management, from one access point to centralized controller. The Wireless network Control Protocol allows for access and control of large-scale wireless local area networks. It can allows management of these networks, Control and Provisioning of Wireless Access Points In computer networking, a wireless access point is a device that allows wireless devices to connect to wired network using Wi-Fi, Bluetooth or related standards. The WAP usually connects to a router via a wired network, and can relay data between the wireless devices such as computers or printers and wired devices on the network

Computer Tool With a Code Generator for Avionic Distributed Fuel Control Systems With Smart Sensors and Actuators

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> This paper describes the development of a graphic computer tool that facilitates the generation of control software for a new distributed fuel management system for aircraft. The system has been the result of a three-year European Community Research Project. The goal was to move from a centralized control architecture to a fully distributed one, where each component of the system makes a decision by itself and the control of the whole system is a shared task. The interchange of information between components is performed via fieldbuses. The graphic computer tool developed is able to perform an automatic code generation starting from a graphic description of the system provided by the user. Thus, different aircraft fuel system configurations can be considered. According to the specific aircraft under study, they can include more or less tanks and components in the system. For each case, the control code of the distributed system can be quickly modified. It can, then, be integrated in each component device to operate in the system. This paper describes the main ideas of the new distributed avionic system and the graphical tool. Some experimental results in a laboratory plant simulator are also shown. </para>

Multi-robot cooperation-based mobile printer system

This paper proposes a mobile printer system (MPS) based on multi-robot cooperation. The system consists of multiple mobile robots, a wireless LAN system, a graphic user interface (GUI), and a host computer. The GUI comprises a user input section, a task allocation optimization section, and a control and communication section. Its operation is as follows: a user draws a picture on an input window of the GUI, and then the host computer commands client printer-robots to reproduce the same on a paper in a finite time. To control multiple robots during this process, two kinds of multi-robot control architectures along with a collision-free arbitration configuration are proposed. One is a decentralized control architecture, which employs subsumption architecture based on behavior-based robotics. The robots continue to seek the nearest line and to draw it repeatedly until all lines are drawn. This architecture needs no pre-planning and is fault-tolerant. Another is a centralized control architecture, which employs an evolutionary algorithm (EA). The host computer optimizes the task (finding time-optimal path) allocation for each robot by using an evolutionary algorithm and sends the optimized job sequence to the robots. To minimize the elapsed time in drawing all the lines, an evolutionary algorithm with a representation of an individual suitable for the MPS is employed for the task optimization. This architecture can minimize the elapsed time effectively and offers the option of distance-optimality in addition to time-optimality. The proposed architectures are simulated and real experiments with three omni-directional robots are carried out to demonstrate the effectiveness and the applicability of the proposed mobile printer system.

A Fully Distributed Architecture for Large Scale Workflow Enactment

Standard client-server workflow management systems are usually designed as client-server systems. The central server is responsible for the coordination of the workflow execution and, in some cases, may manage the activities database. This centralized control architecture may represent a single point of failure, which compromises the availability of the system. We propose a fully distributed and configurable architecture for workflow management systems. It is based on the idea that the activities of a case (an instance of the process) migrate from host to host, executing the workflow tasks, following a process plan. This core architecture is improved with the addition of other distributed components so that other requirements for Workflow Management Systems, besides scalability, are also addressed. The components of the architecture were tested in different distributed and centralized configurations. The ability to configure the location of components and the use of dynamic allocation of tasks were effective for the implementation of load balancing policies.

The control of rocket fairing interior noise with a networked embedded system

Numerous investigations have been conducted with the purpose of attenuating the acoustic environment within rocket payload fairings. These, to date, theoretical and experimental laboratory studies have demonstrated a great deal of success. However, practical applications to this, and other large‐scale noise control problems, have been limited in their success. These limitations are due to nonscalable control systems, weight constraints and complexity. This work seeks to address these limitations by investigating the use of an array of networked embedded processors to control the interior acoustics of a rocket fairing. This networked embedded system consists of numerous computationally elements, paired with appropriate sensors and actuators, that communicate with each other over a wired or wireless network. The goal of the network is to minimize the interior acoustic level while expending a minimum amount of energy. Results from the simulation of such a control system will demonstrate the effectiveness of such an approach. These results will also be compared with those obtained by traditional, centralized control architectures.

The Shared Control Parallel Architecture Model

SIMD machines are considered special purpose architectures chiefly because of their inability to support control parallelism. This restriction exists because there is a single control unit that is shared at the thread level; concurrent control threads must time-share the control unit (they are sequentially executed). We present an alternative model for building centralized control architectures that allows better support for control parallelism. This model, called shared control, shares the control unit(s) at the instruction level. More precisely, in each cycle the control signals for all the supported instructions are broadcast to the PEs. In turn, each PE receives its control by synchronizing with the control unit responsible for its local instruction. The shared control model is fundamentally different from the SIMD model. There are a number of architectural issues that must be resolved in order for this model to be useful. This paper identifies some of these issues and discusses their respective trade-off spaces. An integrated shared-control/SIMD architecture design (SharC) is presented and used to demonstrate the relative performance relative to a SIMD architecture.

Development of a multi-behavior based mobile robot for remote supervisory control through the Internet

We review the networked mobile robot systems and suggest taxonomy based on the three levels of control commands. The performance analysis result shows that direct control has potential difficulty for implementation due to the unpredicted transmission delay of the network. To tackle this problem, we have suggested the behavior-programming control concept to avoid disturbances of the Internet latency. For this purpose, primitive local intelligence of the mobile robot is grouped into motion planner, motion executor, and motion assistant, where each of a group is treated as an agent. They are integrated by centralized control architecture based on multi-agent concept, communicated through a center information memory. The event-driven concept is applied on the robot to switch the behaviors to accommodate the unpredicted mission autonomously. We have successfully demonstrated experimentally the feasibility and reliability for system through a performance comparison with direct remote control.

Decentralized control of distributed intelligent robots and subsystems

In a distributed robot system, asynchronous and synchronous communication between the system components is necessary to guarantee problem soliving capability in realtime. On that account, the distributed control architecure of the Karlsruhe Autonomous Mobile Robot KAMRO which is being developed at IPR has been extended by these communication kinds. The robot system consists of several subcomponents, like manipulators, two hand-eyecameras, one overhead camera and a mobile platform. To get better problem solving capability than the former centralized control architecture, these components are able to work together in teams (asynchronous communication) or special agents (synchronous communication).

Congestion control for intelligent networks

Abstract Due to the centralized control architecture in Intelligent Networks (INs), Service Control Points (SCPs) working as central servers have to carry out a great variable number of service requests coming from underlying Service Switching Points (SSPs). Appropriate congestion control considering the special IN aspects is required. In view of the importance of insuring SCP thruput during network overload, it was judged worthwhile to perform a comparative study of the effectiveness of two different SCP congestion control methods. The first one is the call rate based control using the call gapping or leaky bucket principle, the second one is the window method. This study required the development of a simulation program, to determine call thruput resulting from use of these methods under various types of overload traffic. Presentation and discussion of the results of these simulations is the primary content of this paper.

Software Structure of No. 5 ESS--A Distributed Telephone Switching System

Most stored program controlled telephone switching systems are designed with centralized control architectures. Evolving processor technology and requirements of smooth growth over a wide size range have led system designers to take advantage of distributed processing architectures. This paper provides a conceptual framework for software partitioning on a distributed stored-program controlled switching system and discusses the resulting software structure as present in No. 5 ESS. To facilitate the software development process, a methodology based on current software engineering principles is employed. Sufficiently decoupled software components have expedited parallel development of software and provided reliability by reducing interaction and limiting propagation of errors among software components. The structuring strategy described for telephone switching is equally applicable to other distributed real-time control systems.