Timestamp Technique Research Articles

Network control based load frequency control considering the transmission delay

AbstractThis study introduces a network‐based controller to regulate frequency within power systems. The primary objective of this investigation is to ensure the stability of power systems experiencing delays in control signal transmission. Initially, a modified networked predictor is proposed to anticipate future signals within a decentralized load frequency control framework. Subsequently, a timestamp technique is employed to actively compensate for the impact of transmission delays. Additionally, an event trigger mechanism is incorporated to complement the extended state observer and optimize signal transmission resource usage. The outcomes of the study indicate that the proposed method effectively mitigates delay effects while maintaining superior performance. Moreover, the proposed method remarkably reduces the required transmission resources.

Resilient Load Frequency Control of Power Systems to Compensate Random Time Delays and Time-Delay Attacks

Load frequency control (LFC) of modern power systems tends to employ open communication networks to transmit measurement/control signals, which makes the LFC scheme more vulnerable to random time delays and time delay attacks. In this paper, a resilient and active time-delay-compensation-based LFC scheme is proposed to compensate the random time delays and time delay attacks. At first, a state observer is employed to estimate the state of the LFC system. Then a networked predictive control method is used to predict the control signals of the system at the future moments. Next, an evaluation and compensation scheme for random time delays and time delay attacks is constructed in the actuator side of the LFC scheme based on the updating period of the actuator and the timestamp technique. Due to the stochastic characteristics of the random time delays or TDAs, the stability condition of the proposed scheme is developed with the aid of the mean square stability theory. Moreover, a dual-loop open communication is employed in the proposed scheme to improve the reliability and resilience. At last, simulation and experiment tests are undertaken to demonstrate the effectiveness of the proposed scheme.

SF-LAP: Secure M2M Communication in IIoT with a Single-Factor Lightweight Authentication Protocol

Machine-to-machine communication allows smart devices like sensors, actuators, networks, gateways, and other controllers to communicate with one another. The industrial Internet of things (IIoT) has become a vital component. Many industrial devices are connected to perform a task automatically in machine-to-machine communication, but they are not properly secured, allowing an adversary to compromise them against a variety of attacks due to communication system vulnerabilities. Recently, a secure lightweight authentication protocol (SLAP) was proposed by Panda et al. They asserted that every known attack that could happen in the IIoT is deterred by their suggested protocol. In this study, we prove that the SLAP protocol is vulnerable to desynchronization, impersonation, replay, and eavesdropping attacks. To prevent these attacks and enhance that protocol, we need to implement a secure authentication mechanism that ensures the security of communication. This paper proposed a secure M2M Communication in IIoT with a single-factor lightweight authentication protocol (SF-LAP). Single-factor authentication is a simple and secure way to communicate. It uses less power and communication overhead while providing a secure mechanism for conversation. In the machine-to-machine (M2M) scenario, the proposed protocol uses an exclusive-OR operation and a hashing function to ensure secure communication between the sensor and the controller. The proposed mechanism uses a secure preshared key and timestamp technique to protect and safeguard this connection against desynchronization attacks and eavesdropping attacks. We used Burrows Abadi Needham (BAN) Gong, Needham, and Yahalom (GNY) logic, and the automated validation of Internet security protocols applications (AVISPA) tool for formal verification and perform a security analysis as an informal verification to make sure the suggested protocol is secure. Analysis that shows the SF-LAP consumes the least computing and communication overhead and is more secure because it prevents desynchronization and eavesdropping attacks to all of the known attacks that are modification attacks, tracing attacks, impersonation, man-in-the-middle, and replay attacks.

Ultrafast atomic view of laser-induced melting and breathing motion of metallic liquid clusters with MeV ultrafast electron diffraction

Under the irradiation of an ultrafast intense laser, solid materials can be driven into nonequilibrium states undergoing an ultrafast solid-liquid phase transition. Understanding such nonequilibrium states is essential for scientific research and industrial applications because they exist in various processes including laser fusion and laser machining yet challenging in the sense that high resolution and single-shot capability are required for the measurements. Herein, an ultrafast diffraction technique with megaelectron-volt (MeV) electrons is used to resolve the atomic pathway over the entire laser-induced ultrafast melting process, from the initial loss of long-range order and the formation of high-density liquid to the progressive evolution of short-range order and relaxation into the metastable low-density liquid state. High-resolution measurements using electron pulse compression and a time-stamping technique reveal a coherent breathing motion of polyhedral clusters in transient liquid aluminum during the ultrafast melting process, as indicated by the oscillation of the interatomic distance between the center atom and atoms in the nearest-neighbor shell. Furthermore, contraction of interatomic distance was observed in a superheated liquid state with temperatures up to 6,000 K. The results provide an atomic view of melting accompanied with internal pressure relaxation and are critical for understanding the structures and properties of matter under extreme conditions.

A Modified EKF for Vehicle State Estimation With Partial Missing Measurements

During vehicle driving, all aspects of data monitorings are not accurate enough for the vehicle, and there may be packet loss of measurement data. In addition, the accuracy of vehicle data is more difficult to guarantee when the vehicle state is continuously changing, which may lead to some potential safety hazards during driving. Consequently, many algorithms, which only use the statistical characteristics of packet loss information, have been proposed to improve the accuracy. However, with the rapid development of technology, the time-stamp technique in sensor networks can obtain packet loss information at the current moment. In contrast, although the time-stamp technique can effectively improve the filter performance, it cannot analyze the convergence of the Riccati equation. Therefore, this paper proposes a modified EKF algorithm for balancing these two algorithms, and meanwhile, simulation experiments test and verify the effectiveness and feasibility of our proposed algorithm.

Further Study on Networked Control Systems with Unreliable Communication Channels

This paper focuses on the fundamental problems of linear quadratic gaussian (LQG) control and stabilization problems for networked control systems (NCSs) with unreliable communication channels (UCCs) where packet dropout, input delay and observation delay occur. These basic issues have attracted extensive attentions due to broad applications. Our contributions are as follows. For the finite horizon case, without time-stamping technique, the optimal estimator is derived by using the novelty method of innovation sequences based on the delayed intermittent observations; A necessary and sufficient condition for the optimal control problem is presented on the basis of the solution to the forward and backward difference equations (FBDEs) and two coupled Riccati equations. For the infinite horizon case, it is shown that under certain assumption, the system can stay bounded in the mean square sense if and only if the algebraic Riccati equation admits the unique positive solution.

Fuzzy-Observer-Based Predictive Stabilization of DC Microgrids With Power Buffers Through an Imperfect 5G Network

This article investigates the fuzzy model predictive control synthesis of a power buffer for dynamic stabilization of a dc microgrid (MG), which is controlled through a low-latency communication network, such as the one envisioned in fifth-generation (5G). The proposed approach employs a Takagi–Sugeno fuzzy model, a fuzzy observer, and a model predictive scheme to alleviate the effects of the 5G-network-induced delays and data loss of the sensor-to-controller and controller-to-actuator links on the dc MG plant response. By employing the so-called time-stamp technique and network delay compensator (NDC), the delays are computed, and the data loss effects are compensated, thus improving the effectiveness and robustness of the proposed controller. In addition, a time-delay-independent observer is proposed to estimate the states of the constant power loads (CPLs) and the power buffer, based on the measured information. Due to the usage of two NDCs, the presented approach is robust against the network delays and results in a small computational burden. To show the merits of the proposed approach, it is applied to a dc MG that feeds two CPLs. Results show the simplicity of designing the observer-based controller and better robustness against the network delays, compared with the state-of-the-art methods. Additionally, software-in-the-loop simulations are presented to prove the practical applicability of the proposed controller.

State Estimation for Systems With Packet Dropping and State Equality Constraints

We consider the linear estimation problem for systems with packet dropping and equality constraints in this brief, where two kinds of constrained estimators will be designed. First, the constrained state estimator is derived based on the projection method and the unconstrained linear minimum mean square error estimator, and the estimator gains can be yielded in terms of the solutions to a Ricatti equation and a Lyapunov equation. However, when referring to the infinite horizon state estimation, there is a need to consider the convergence of the Lyapunov equation. To meet the requirement of the convergence analysis, the condition that the system matrix is stable should be imposed. Then, in order to remove the restrict condition that the system matrix is stable, another constrained state estimator is designed based on the projection method and time-stamp technique, where the estimator gains can be yielded only in terms of the solutions to a Riccati equation. Finally, we give two numerical examples to show that the second constraint estimator is more effective compared with the first constraint estimator.

Networked Fuzzy Predictive Control of Power Buffers for Dynamic Stabilization of DC Microgrids

This letter investigates the fuzzy model predictive control synthesis of networked controlled power buffer for dynamic stabilization of a dc microgrid (MG). The proposed is based on Takagi–Sugeno fuzzy model and model predictive scheme to mitigate the network-induced delays from the sensor-to-controller and controller-to-actuator links. By employing the so-called time-stamp technique and network delay compensator (NDC), the delays are computed and compensated, which improves the effectiveness and robustness of the proposed controller. Due to the usage of two NDCs, the presented approach is robust against the network delays and results in small computational burden. Therefore, it can widely be employed on large distributed power systems. To show the merits of the proposed approach, it is applied to a dc MG that feeds one constant power load. Results show the simplicity of designing the controller and better robustness against the network's delays compared to the state-of-the-art methods. Additionally, hardware-in-the-loop simulations are presented to prove the practical applicability of the proposed controller.

An in vivo translation-reporter system for the study of protein synthesis in zebrafish embryos.

ABSTRACTControl of gene expression at the translation level is increasingly regarded as a key feature in many biological processes. Simple, inexpensive and reliable procedures to visualize sites of protein production are required to allow observation of the spatiotemporal patterns of mRNA translation at subcellular resolution. We present a method, named SPoT (for Subcellular Patterns of Translation), developed upon the original TimeStamp technique ( Lin et al., 2008), consisting in the expression of a fluorescent protein fused to a tagged, self-cleavable protease domain. The addition of a cell-permeable protease inhibitor instantly stabilizes newly produced tagged protein allowing us to distinguish recently synthesized proteins from pre-existing ones. After a brief protease inhibitor treatment, the ratio of tagged versus non-tagged forms is highest at sites where proteins are the most recent, i.e. sites of synthesis. Therefore, by comparing tagged and non-tagged proteins it is possible to spotlight sites of translation. By specifically expressing the SPoT cassette in neurons of transgenic zebrafish embryos, we reveal sites of neuronal protein synthesis in diverse cellular compartments during early development.

Security Analysis and Enhancement of the Most Recent RFID Authentication Protocol for Telecare Medicine Information System

Radio frequency identification (RFID) technology has been used in a wide variety of applications, more recently as a leading identification technology in healthcare environments. In the most recent years, this technology is adopted for telecare medicine information system (TMIS) for authentication, safety, security, data confidentiality and patient’s privacy protection over public networks. TMIS is the bridge between patients at home and doctors at healthcare organizations that permits to confirm the correctness of exchanged information between different actors of the system. Recently, several RFID authentication schemes have been presented and suggested for the TMIS in the literature. These schemes try to resolve the security and privacy problems over insecure healthcare networks environments by exploiting different cryptographic primitive’s solutions. In this paper, we analyze in depth the security of the most recent proposed protocol for TMIS in the literature and find out its main vulnerabilities. The proposed attacks are possible due to some weaknesses related to the misuse of the timestamp technique, the calculation of the reader request and tag response messages using the one-way hash function, which are not attentively scrutinized. Furthermore, we propose an efficient and robust improved mobile authentication protocol with high efficiency and security for TMIS. The performance analysis shows that our improved protocol could solve security weaknesses of the studied protocol and provide mobility, efficiency and is well-suited to adoption for TMIS.

Dual cooperative RFID‐telecare medicine information system authentication protocol for healthcare environments

AbstractRadio Frequency IDentification (RFID) technology is used in a wide variety of applications, more recently as a leading identification technology in healthcare environments. In the most recent years, this technology has been adopted for telecare medicine information system (TMIS) for authentication, safety, security, data confidentiality, and patient's privacy protection over public networks. TMIS is the bridge between patients at home and doctors at healthcare organizations that permits to validate the correctness of exchanged information between different actors of the system. Recently, several RFID and smart cards authentication schemes have been presented and suggested for the TMIS in the literature. These schemes try to resolve the security and privacy problems over insecure healthcare network environments by exploiting different cryptographic primitive's solutions. In this paper, we first highlighted the vulnerabilities of the most recent proposed protocol for TMIS in the literature and proposed attacks based on the weaknesses related to the misuse of the timestamp technique, the calculation of the reader request and tag response messages using the one‐way hash function, which are not attentively scrutinized. Second, we propose an efficient dual RFID‐TMIS mobile authentication protocol with high efficiency and security for healthcare systems. Our proposal is an improvement and extension of the protocol of Li et al., where we propose to associate the RFID technology with TMIS in the same authentication system to take advantages of both these two promising technologies. The performance analysis shows that our improved protocol could solve security weaknesses of the studied protocol and provide mobility, efficiency and is well suited for TMIS adoption in remote areas and low population density. Copyright © 2016 John Wiley & Sons, Ltd.

Về một ứng dụng của vector time trong các hệ CSDL phân tán

For the concurrence control algorithms using timestamp technique in Distributed Database Systems, the technique of generating labels for the events is very important. This paper presents the method of generating label that bases on the technique of Vector time for concurrence control algorithms in Distributed Database Systems. An algorithm basing on this method has been presented. The evaluation of performance of algorithm is also examined.

Data‐based predictive control for networked non‐linear systems with two‐channel packet dropouts

This study is concerned with the data-based control of networked non-linear control systems with random packet dropouts in both the sensor-to-controller and controller-to-actuator channels. By taking advantage of the characteristics of networked control systems such as the packet-based transmission, timestamp technique, as well as smart sensor and actuator, a data-based networked predictive control (DBNPC) method is proposed to actively compensate for the two-channel packet dropouts, where only the input and output data of the non-linear plant are required. A sufficient condition for the stability of the closed-loop system is developed. Furthermore, the resulting DBNPC system can achieve a zero steady-state output tracking error for step commands. Finally, extensive simulation results on a networked non-linear system demonstrate the effectiveness of the proposed method.

Design of Networked Control System with Time-Delay and Packet Loss

For Networked Control System (NCS) with random network-induced delay and packet loss, an observer is designed to reconstruct the states using output values. A piece-wise time-delay strategy and the timestamp technique are used, improving the system performance. Depending on whether data dropout occurs or not, system is modeled as an Asynchronous Dynamical System (ADS), and theorem guaranteeing the system closed-loop stability is also given. Based on Lyapunov and Linear Matrix Inequality (LMI), controller gain and observer gain are solved and TrueTime toolbox is used to verify the effectiveness of the algorithm.

Adding accurate timestamping capability to wireless networks for smart grids

Smart grids rely on bi-directional communications between energy production sites and utilization sites. Usually, different approaches are used for implementing the required Wide, Field, and Home Area Networks (WAN, FAN and HAN, respectively). These networks are realized using very different (hybrid) technologies, for instance wired for WAN and wireless for FAN and HAN. However, an accurate common sense of time must be guaranteed among all smart grid participants, as it happens in any other distributed systems. Satisfying this need is challenging for wireless networks, while mature time distribution technologies are available for wired networks. The major issue for wireless devices is to provide accurate timestamping of network events, the key element of any time synchronization protocol. The objective of this paper is to propose low-cost and low-complexity timestamping techniques that also maintain full compatibility with already existing (unlicensed) communication standard for wireless nodes used in smart grids. In addition, a suitable platform exploiting the Software Defined Radio paradigm for comparative evaluation of these techniques is also discussed. Simulation and experimental results confirm the feasibility of the proposed approach, with the standard deviation of the timestamping error scalable down to 5ns.

Provably secure three-party authenticated key agreement protocol using smart cards

Authenticated key agreement protocol is a useful cryptographic primitive, which can be used to protect the confidentiality, integrity and authenticity for transmitted data over insecure networks. From the point of view of the management of pre-shared secrets, one of the advantages of three-party authenticated key agreement (3PAKA) protocols is that they are more suitable for use in a network with large numbers of users compared with two-party authenticated key agreement protocols. Using smart cards is a practical, secure measure to protect the secret private keys of a user. Recently, some 3PAKA protocols using smart cards have been proposed. However, up to now, it is still a challenging problem to propose a 3PAKA protocol using smart cards with fewer rounds of messages and without using timestamp technique. Another important fact to be mentioned is that existing 3PAKA protocols using smart cards all lack provable-security guarantees. In this paper, we propose a new 3PAKA protocol using smart cards. The proposed protocol gains several advantages over existing related protocols: (1) The protocol is provably secure under the computational Diffie–Hellman assumption in the random oracle model, and hence can resist strong adversaries in network scenarios; (2) The protocol needs fewer rounds of messages, and can enable short communication latency and rapid response; and (3) The protocol is not based on timestamp technique, and does not need the complicated clock synchronization.

무선 인체 영역 네트워크(WBAN)를 위한 실용적인 인증 시스템

In this paper, we propose a practical authentication system based on Wireless Body Area Networks(WBAN) for U-healthcare medical information environments. The proposed authentication system is based on symmetric cryptosystem such as AES and is designed to not only provide security such as data secrecy, data authentication, data integrity, but also prevent replay attack by adopting timestamp technique and perform secure authentication between sensor node, master node, base-station, and medical server.

An efficient and secure multi-server authentication scheme with key agreement

Remote user authentication is used to validate the legitimacy of a remote log-in user. Due to the rapid growth of computer networks, many network environments have been becoming multi-server based. Recently, much research has been focused on proposing remote password authentication schemes based on smart cards for securing multi-server environments. Each of these schemes used either a nonce or a timestamp technique to prevent the replay attack. However, using the nonce technique to withstand the replay attack is potentially susceptible to the man-in-the-middle attack. Alternatively, when employing the timestamp method to secure remote password authentication, it will require the cost of implementing clock synchronization. In order to solve the above two issues, this paper proposes a self-verified timestamp technique to help the smart-card-based authentication scheme not only effectively achieve password-authenticated key agreement but also avoid the difficulty of implementing clock synchronization in multi-server environments. A secure authenticated key agreement should accomplish both mutual authentication and session key establishment. Therefore, in this paper we further give the formal proof on the execution of the proposed authenticated key agreement scheme.

Time stamp technique using a nuclear emulsion multi-stage shifter for gamma-ray telescope

Nuclear emulsion has a potential use as a gamma-ray telescope with high angular resolution. For this application it is necessary to know the time when each track was recorded in the emulsion. In previous experiments using nuclear emulsion, various efforts were used to associate time to nuclear emulsion tracks and to improve the time resolution. Using a high speed readout system for nuclear emulsion together with a clock-based multi-stage emulsion shifter, we invented a technique to give a time-stamp to emulsion tracks and greatly improve the time resolution. A test experiment with a 2-stage shifter was used to demonstrate the principle of multi-stage shifting, and we achieved a time resolution 1.5 s for 12.1 h (about 1 part in 29 000) with the time stamp reliability 97% and the time stamp efficiency 98%. This multi-stage shifter can achieve the time resolution required for a gamma-ray telescope and can also be applied to another cosmic ray observations and accelerator experiments using nuclear emulsion.