Scalable Control Research Articles

Stochastic modeling and scalable predictive control for automated demand response

AbstractAutomated demand response (ADR) is a utility program that is designed to achieve electricity conservation. An ADR program is regarded as the problem of controlling the power consumption of a set of consumers. In this article, we propose a control‐theoretic approach for an ADR program. First, a mathematical model of the power consumption is proposed. This model can express complex behavior by switching a Markov chain. Its effectiveness is illustrated by modeling the power consumption of an air‐conditioner. Next, a new method of model predictive control for a set of consumers is developed using the proposed model. The control strategy at each time is chosen from a given finite set by solving a mixed integer linear programming (MILP) problem. The advantage of the proposed method is that the MILP problem is scalable with respect to the number of consumers. To show its effectiveness, we present a numerical example.

Minimal Fault-Tolerant Coverage of Controllers in IaaS Datacenters

Large-scale datacenters are the key infrastructures of cloud computing. Inside a datacenter, a large number of servers are interconnected using a specific datacenter network to deliver the infrastructure as a service (IaaS) for tenants. To realize novel cloud applications like the network virtualization and network isolation among tenants, the principle of software-defined network (SDN) has been applied to datacenters. In the setting, multiple distributed controllers are deployed to offer a control plane over the entire datacenter to efficiently manage the network usage. Despite such efforts, cloud datacenters, however, still lack a scalable and resilient control plane. Consequently, this paper systematically studies the coverage problem of controllers, which means to cover all network devices using the least number of controllers. More precisely, we tackle this essential problem from three aspects, including the minimal coverage, the minimal fault-tolerant coverage, and the minimal communication overhead among controllers. After modelling and analyzing such three problems, we design efficient approaches to approximate the optimal solution, respectively. Extensive evaluation results indicate that our approaches can significantly save the number of required controllers, improve the fault-tolerant capability of the control plane and reduce the communication overhead of state synchronization among controllers. The design methodologies proposed in this paper can be applied to cloud datacenters with other networking structures after minimal modifications.

A Novel Fair and Scalable Relay Control Scheme for Internet of Things in LoRa-Based Low-Power Wide-Area Networks

This article proposes a novel fair and scalable relay control (FSRC) scheme for the Internet-of-Things (IoT) services in long range (LoRa)-based low-power wide-area networks. The proposed FSRC scheme promotes relay operation with low spreading factor (SF) to improve the success probability for distant end-devices (EDs) and the fairness of success probability for each SF region. To achieve this, a theoretical framework for designing the relay operation is analytically developed by considering a practical LoRaWAN MAC protocol as an analytical model. The proposed FSRC scheme encompasses a selective relay operation by considering both signal-to-noise ratio and signal-to-interference ratio and the receive signal strength indicator value for the location-unaware relay selection strategy. Using this model, a genetic algorithm-based relay control strategy is proposed to maximize both coverage probability and minimum success probability for all SF regions by controlling the relay parameters, such as source-relay region and source-relay ratio. Our numerical analysis validates the effectiveness of the proposed FSRC scheme under various parameters in terms of the minimum success probability of each SF region, coverage probability, and fairness. Specifically, we verify that the proposed FSRC scheme achieves a maximum of approximately 37% and 33% improvement of the minimum success probability and coverage probability, respectively, under practical LoRa PHY/MAC parameters, compared to the single-hop environment (without relay operation).

Distributed Control Design for Heterogeneous Interconnected Systems

This article presents scalable controller synthesis methods for heterogeneous and partially heterogeneous systems. First, heterogeneous systems composed of different subsystems that are interconnected over a directed graph are considered. Techniques from robust and gain-scheduled controller synthesis are employed, in particular, the full-block S-procedure, to deal with the decentralized system part in a nominal condition and with the interconnection part in a multiplier condition. Under some structural assumptions, we can decompose the synthesis conditions into conditions that are the size of the individual subsystems. To solve these decomposed synthesis conditions that are coupled only over neighboring subsystems, we propose a distributed method based on the alternating direction method of multipliers. It only requires nearest-neighbor communication and no central coordination is needed. Then, a new classification of systems is introduced that consists of groups of homogeneous subsystems with different interconnection types. This classification includes heterogeneous systems as the most general and homogeneous systems as the most specific case. Based on this classification, we show how the interconnected system model and the decomposed synthesis conditions can be formulated in a more compact way. The computational scalability of the presented methods with respect to a growing number of subsystems and interconnections is analyzed, and the results are demonstrated in numerical examples.

Secure and scalable access control protocol for IoT environment

Smart applications based on IoT has gained huge momentum in recent times. Typically, these applications involve the deployment of smart devices within the perception layer of three-tier IoT architecture. The smart devices may be required to be re-deployed due to adversary attacks, or outage of power. Deployment of new smart devices within the perception layer of IoT based applications is a significant security concern. The deployed smart device can be a malicious node that can disrupt the complete network operations. An access control protocol regulates the deployment of smart devices within the perception layer. Besides obliging the resource constraint nature of smart devices, an access control protocol must also fulfill specific security and functional requirements for its practical consideration. In this paper, an access control protocol based on Elliptical Curve Cryptography (ECC) has been presented. Besides sufficing to all other major security and functional requirements, the proposed protocol is also scalable and independent of clock synchronization issues. The correctness and the soundness of the proposed protocol has been validated using BAN logic. The proposed protocol has also been formally validated using automated validation of internet security protocols and applications (AVISPA) and Scyther tools. The proposed protocol has been compared with relevant existing schemes on various security and functional requirements. The comparison suggests that the proposed protocol has a better trade-off as compared to relevant existing schemes.

A Scalable Cryo-CMOS Controller for the Wideband Frequency-Multiplexed Control of Spin Qubits and Transmons

Building a large-scale quantum computer requires the co-optimization of both the quantum bits (qubits) and their control electronics. By operating the CMOS control circuits at cryogenic temperatures (cryo-CMOS), and hence in close proximity to the cryogenic solid-state qubits, a compact quantum-computing system can be achieved, thus promising scalability to the large number of qubits required in a practical application. This work presents a cryo-CMOS microwave signal generator for frequency-multiplexed control of 4 × 32 qubits (32 qubits per RF output). A digitally intensive architecture offering full programmability of phase, amplitude, and frequency of the output microwave pulses and a wideband RF front end operating from 2 to 20 GHz allow targeting both spin qubits and transmons. The controller comprises a qubit-phase-tracking direct digital synthesis (DDS) back end for coherent qubit control and a single-sideband (SSB) RF front end optimized for minimum leakage between the qubit channels. Fabricated in Intel 22-nm FinFET technology, it achieves a 48-dB SNR and 45-dB spurious-free dynamic range (SFDR) in a 1-GHz data bandwidth when operating at 3 K, thus enabling high-fidelity qubit control. By exploiting the on-chip 4096-instruction memory, the capability to translate quantum algorithms to microwave signals has been demonstrated by coherently controlling a spin qubit at both 14 and 18 GHz.

A scalable and secure attribute-based access control method in Internet of Things with efficient revocation

The Internet of Things (IoT) is an emerging network paradigm that understands the Because IoT is connections between all things and is the foundation of the intelligent community. The pervasive, always about everyday life or daily work of the user, privacy and security are important.
 In other complex and heterogeneous properties of the IoT make its security issues very challenging. words, how to achieve data, while data privacy is a challenging task. In addition, resource constraints In spite of the attribute based of node creates a lightweight requirement for IoT security mechanisms. encryption like (CP-ABE), can provide access control to data by allowing specific users who their This paper provides a method of a attributes in accordance with the policy of access to decoded text. scalable and secure access control based on attribute with effective revocation based on allow users to access and as well as the possibility of expiring some users' access. Security and efficiency evaluations show that the proposed scheme can achieve the desired security goals, while keeping comparable
 computation overhead.

Designing a DDS-Based SoC for High-Fidelity Multi-Qubit Control

The design of a large-scale quantum computer requires co-optimization of both the quantum bits (qubits) and their control electronics. This work presents the first systematic design of such a controller to simultaneously and accurately manipulate the states of multiple spin qubits or transmons. By employing both analytical and simulation techniques, the detailed electrical specifications of the controller have been derived for a single-qubit gate fidelity of 99.99% and validated using a qubit Hamiltonian simulator. Trade-offs between several architectures with different levels of digitization are discussed, resulting in the selection of a highly digital DDS-based solution. Initiating from the system specifications, a complete error budget for the various analog and digital circuit blocks is drafted and their detailed electrical specifications, such as signal power, linearity, spurs and noise, are derived to obtain a digital-intensive power-optimized multi-qubit controller. A power consumption estimate demonstrates the feasibility of such a system in a nanometer CMOS technology node. Finally, application examples, including qubit calibration and multi-qubit excitation, are simulated with the proposed controller to demonstrate its efficacy. The proposed methodology, and more specifically, the proposed error budget lay the foundations for the design of a scalable electronic controller enabling large-scale quantum computers with practical applications.

A New Scalable and Expandable Access Control Model for Distributed Database Systems in Data Security

Access control models are an important tool developed for securing today’s data systems. Institutions use the access control models specifically to define who their employees are, what they can do, which resources they can reach, and which processes they can perform and use them to manage the whole process. This is a very hard and costly process for institutions with distributed database systems. However, access control models cannot be implemented in a qualified way due to the fact that the conditions for defining users’ demands to reach resources distributed on different servers, one of which is consequentially bound to the other, the verification and authorization of those user demands, and being able to monitor the actions of the users cannot be configured in an efficient way all the time. With our model suggested in this study, the aim is to automatically calculate the permissions and access levels of all users defined in the distributed database systems for the objects, and, in this way, we will reach a more efficient decision as to which objects the users can access while preventing their access to the information they do not need. Our proposed model in this study has been applied to real life data clusters from organizations providing health and education services and a public service. With the proposed model, all models have been run on servers sharing resources in a private network. The performance of the proposed model has been compared to that of traditional access models. It was confirmed that the proposed model presented an access control model providing more accurate access level results as well as being scalable to many distributed database systems.

RabbitQC: high-speed scalable quality control for sequencing data.

Modern sequencing technologies continue to revolutionize many areas of biology and medicine. Since the generated datasets are error-prone, downstream applications usually require quality control methods to pre-process FASTQ files. However, existing tools for this task are currently not able to fully exploit the capabilities of computing platforms leading to slow runtimes. We present RabbitQC, an extremely fast integrated quality control tool for FASTQ files, which can take full advantage of modern hardware. It includes a variety of operations and supports different sequencing technologies (Illumina, Oxford Nanopore and PacBio). RabbitQC achieves speedups between one and two orders-of-magnitude compared to other state-of-the-art tools. C++ sources and binaries are available at https://github.com/ZekunYin/RabbitQC. Supplementary data are available at Bioinformatics online.

A permission‐combination scalable access control model for Internet of things

AbstractDevelopment of the Internet of things (IoT) is considered as one of the major events in modern manufacturing industry, and IoT devices are expected to create and exchange vast amounts of data, thereby bringing forth unprecedented challenges in terms of robust and vendor‐neutral data sharing. While access control is widely used to protect the security of data sharing, it still has some security flaws and limitations, such as privacy leakage, fixed access permissions, security vulnerabilities, and so on. Aiming at these problems, this article proposes a permission‐combination scalable access control (PCS‐AC) scheme, in which the methods of access permissions assignment, data encryption, and data access are given. In contrast to prior works, PCS‐AC differs in several significant ways: (1) it supports anonymous access and traceability. Anonymous access can prevent leakage of users' privacy. Traceability can track the illegally accessed entity when the resource is illegally accessed; (2) it supports scalable access to data resources. Users use a combination of attribute permissions to access data at different security levels; (3) it achieves high efficiency because the entity can quickly search ciphertext resources by plaintext keywords. After searching and downloading the ciphertext, decrypt it by group key to obtain the corresponding plaintext information. PCS‐AC is proven secure under the hardness assumption of Discrete Logarithm problem and Inverse Computational Diffe‐Hellman problem. The performance analysis shows that PCS‐AC has higher efficiency than the referred works.

Structured Massive Access for Scalable Cell-Free Massive MIMO Systems

How to meet the demand for increasing number of users, higher data rates, and stringent quality-of-service (QoS) in the beyond fifth-generation (B5G) networks? Cell-free massive multiple-input multiple-output (MIMO) is considered as a promising solution, in which many wireless access points cooperate to jointly serve the users by exploiting coherent signal processing. However, there are still many unsolved practical issues in cell-free massive MIMO systems, whereof scalable massive access implementation is one of the most vital. In this paper, we propose a new framework for structured massive access in cell-free massive MIMO systems, which comprises one initial access algorithm, a partial large-scale fading decoding (P-LSFD) strategy, two pilot assignment schemes, and one fractional power control policy. New closed-form spectral efficiency (SE) expressions with maximum ratio (MR) combining are derived. The simulation results show that our proposed framework provides high SE when using local partial minimum mean-square error (LP-MMSE) and MR combining. Specifically, the proposed initial access algorithm and pilot assignment schemes outperform their corresponding benchmarks, P-LSFD achieves scalability with a negligible performance loss compared to the conventional optimal large-scale fading decoding (LSFD), and scalable fractional power control provides a controllable trade-off between user fairness and the average SE.

An All-wireless SDN Framework for BLE Mesh

The Internet of Things (IoT) paradigm combines the interconnection of massive amounts of battery-constrained and low-computational-power devices with low-latency and high-reliability network requirements. Additionally, diverse end-to-end services and applications with different Quality of Service (QoS) requirements are expected to coexist in the same network infrastructure. Software-defined Networking (SDN) is a paradigm designed to solve these problems, but its implementation in wireless networks and especially in the resource-constrained IoT systems is extremely challenging and has seen very limited adoption, since it requires isolation of data and control plane information flows and a reliable and scalable control plane. In this work, Bluetooth Low Energy (BLE) mesh is introduced as an adequate technology for an all-wireless SDN-BLE implementation, which is a technology that has become the de-facto standard for IoT. The proposed SDN-BLE framework uses a routing network slice for the data plane information flow and a flooding network slice for the control plane information flow, ensuring their isolation while still being transmitted over the wireless medium. The design and implementation of all the classical SDN layers on a hybrid BLE mesh testbed is given, where the data plane is formed by the BLE nodes and the control plane can be centralized on a server or distributed over several WiFi gateways. Several controllers are described and implemented, allowing the framework to obtain end-to-end network knowledge to manage individual nodes over the air and configure their behavior to meet application requirements. An experimental characterization of the SDN-BLE framework is given, where the impact of the different parameters of the system on the network reliability, overhead, and energy consumption is studied. Additionally, the distributed versus centralized control plane operation modes are experimentally characterized, and it is shown that the distributed approach can provide the same performance as the centralized one when careful system design is performed. Finally, a proof of concept for the SDN-BLE framework is presented, where a network congestion is automatically detected and the nodes responsible of such congestion are identified and reconfigured over the air, bypassing the congested links, to resume regular network performance.

A Waypoint Tracking Controller for Autonomous Road Vehicles Using ROS Framework.

Automated Driving Systems (ADSs) require robust and scalable control systems in order to achieve a safe, efficient and comfortable driving experience. Most global planners for autonomous vehicles provide as output a sequence of waypoints to be followed. This paper proposes a modular and scalable waypoint tracking controller for Robot Operating System (ROS)-based autonomous guided vehicles. The proposed controller performs a smooth interpolation of the waypoints and uses optimal control techniques to ensure robust trajectory tracking even at high speeds in urban environments (up to 50 km/h). The delays in the localization system and actuators are compensated in the control loop to stabilize the system. Forward velocity is adapted to path characteristics using a velocity profiler. The controller has been implemented as an ROS package providing scalability and exportability to the system in order to be used with a wide variety of simulators and real vehicles. We show the results of this controller using the novel and hyper realistic CARLA Simulator and carrying out a comparison with other standard and state-of-art trajectory tracking controllers.

Scalable and secure access control policy for healthcare system using blockchain and enhanced Bell–LaPadula model

Access control is a policy in data security that controls access to resources. The current access control mechanisms are facing many problems, due to the interference of the third-party, privacy, and security of data. These problems can be addressed by blockchain, the technology that gained major attention in recent years and has many capabilities. However, in the blockchain network, every peer maintains the same state of the ledger to view the complete history of transactions that leads to scalability issues in the blockchain network. To address the problem of scalability we propose an enhanced Bell–LaPadula model and categorized the peers and transactions in different clearance and security levels. The peers don’t have to maintain the complete history of transactions owing to the clearance level. To provide data security in the network we constructed a dynamic access control policies using a smart contracts. We test our model on a blockchain-based healthcare network. The Hyperledger Fabric tool is used to run a complete infrastructure of healthcare organization while the Hyperledger composer modeling tool is used to implement the smart contracts and to provide dynamic access control functionality on the blockchain network.

A single-hole spin qubit

Qubits based on quantum dots have excellent prospects for scalable quantum technology due to their compatibility with standard semiconductor manufacturing. While early research focused on the simpler electron system, recent demonstrations using multi-hole quantum dots illustrated the favourable properties holes can offer for fast and scalable quantum control. Here, we establish a single-hole spin qubit in germanium and demonstrate the integration of single-shot readout and quantum control. We deplete a planar germanium double quantum dot to the last hole, confirmed by radio-frequency reflectrometry charge sensing. To demonstrate the integration of single-shot readout and qubit operation, we show Rabi driving on both qubits. We find remarkable electric control over the qubit resonance frequencies, providing great qubit addressability. Finally, we analyse the spin relaxation time, which we find to exceed one millisecond, setting the benchmark for hole quantum dot qubits. The ability to coherently manipulate a single hole spin underpins the quality of strained germanium and defines an excellent starting point for the construction of quantum hardware.

Laser Pouch Motors: Selective and Wireless Activation of Soft Actuators by Laser-Powered Liquid-to-Gas Phase Change

Untethered control of soft-bodied robots is attractive for interactions in a variety of unstructured and dynamic environments. However, soft robotics systems are currently limited in terms of wireless, selective, and scalable control of multiple actuators. Therefore, we propose a method to wirelessly drive multiple soft actuators by laser projection. A small amount of low-boiling-point liquid inside a planar thin pouch can be heated by a laser and evaporated to inflate the whole body. Laser projection enables both wireless energy supply and the selection of target actuators. Further, the low-boiling-point liquid serves as an actuation source and as a receiver of laser irradiation. Thus, we do not need additional components such as electric circuits and batteries to achieve simple and scalable implementation of multiple soft actuators. We evaluated the mechanical properties and demonstrated that the system can wirelessly control the gestures of fingers of a robot hand. We also verified that our method can activate a group of mobile soft robots simultaneously and individually while tracking the actuator positions. Our approach contributes to the scalable deployment of soft robotic systems by removing tethers for power and communication.

Electrically controlled rapid adiabatic passage in a single quantum dot

We demonstrate electrically controlled robust state preparation of an exciton qubit by rapid adiabatic passage with Fourier-limited laser pulses. In our approach, resonant ps laser pulses are applied to generate excitonic population in a quantum dot, whereas synchronously applied ps electric transients provide a controlled sweep of the exciton transition energy. The ps electric transients applied to the quantum dot in a diode structure result in ultrafast Stark shifts of the exciton energy on time scales below the decoherence time of the exciton. We experimentally demonstrate that the tailored electric chirp of the exciton energy leads to a controlled rapid adiabatic passage, which results in a robust state preparation of the exciton. Our experimental results are confirmed by a theoretical analysis of the chirped coherent manipulation of the exciton two level system. Our approach toward optoelectronic quantum control paves the way for broader applications that require a scalable control of functional coherent systems.

A review on control systems hardware and software for robots of various scale and purpose. Part 3. Extreme robotics

A review of robotic systems is carried out. The paper analyzes applied hardware and software solutions and summarizes the most common block diagrams of control systems. The analysis of approaches to control systems scaling, the use of intelligent control, achieving of fault tolerance, reducing the weight and size of control system elements belonging to various classes of robotic systems is carried out. The goal of the review is finding common approaches used in various areas of robotics to build on their basis a uniform methodology for designing scalable intelligent control systems for robots with a given level of fault tolerance on a unified component base. This part is dedicated to extreme robotics and the generalization of the conclusions for the whole review. The paper notes the possibility and necessity of developing common approaches to the creation of robots of various sizes and purposes. It is noted that, in contrast to many foreign countries, in the Russian Federation developers must consider the serious limitations on the electronics components, which do not allow for the free conversion of technologies between civilian, military and space robotics. In this regard, it is proposed to analyze the interchangeable Russian and foreign microelectronic components, to find technical solutions in the field of the control systems and communication between them, which could be implemented both in foreign and Russian microelectronics, and to create on their basis a conceptual model of scalable intelligent control system with a required level of fault tolerance. The model should be based on a unified set of components.

Layer-to-Layer Predictive Control of Inkjet 3-D Printing

This article develops and experimentally validates a distributed predictive control algorithm for closed-loop control of inkjet 3-D printing to handle constraints, e.g., droplet volume bounds, as well as the large-scale nature of the 3-D printing problem. The large number of decision variables, i.e., droplet volumes at each grid point, in high resolution inkjet 3-D printing makes centralized methods extremely time-consuming, thus, a distributed implementation of the controller is necessary. First, a graph-based height evolution model that captures the liquid spreading dynamics is described. Based on this model, a scalable closed-loop control algorithm using distributed model predictive control (MPC) that can reduce computation time significantly is designed and experimentally implemented. The performance and efficiency of the algorithm are shown to outperform open-loop printing and closed-loop printing with existing centralized MPC methods.