1,532 research outputs found

    Elevation, pitch and travel axis stabilization of 3DOF helicopter with hybrid control system by GA-LQR based PID controller

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    This research work presents an efficient hybrid control methodology through combining the traditional proportional-integral-derivative (PID) controller and linear quadratic regulator (LQR) optimal controlher. The proposed hybrid control approach is adopted to design three degree of freedom (3DOF) stabilizing system for helicopter. The gain parameters of the classic PID controller are determined using the elements of the LQR feedback gain matrix. The dynamic behaviour of the LQR based PID controller, is modeled and the formulated in state space form to enable utlizing state feedback controller technique. The performance of the proposed LQR based LQR controller is improved by using Genetic Algorithm optimization method which are adopted to obtain optimum values for LQR controller gain parameters. The LQR-PID hybrid controller is simulated using Matlab environment and its performance is evaluated based on rise time, settling time, overshoot and steady state error parameters to validate the proposed 3DOF helicopter balancing system. Based on GA tuning approach, the simulation results suggest that the hybrid LQR-PID controller can be effectively adopted to stabilize the 3DOF helicopter system

    Balancing a Segway robot using LQR controller based on genetic and bacteria foraging optimization algorithms

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    A two-wheeled single seat Segway robot is a special kind of wheeled mobile robot, using it as a human transporter system needs applying a robust control system to overcome its inherent unstable problem. The mathematical model of the system dynamics is derived and then state space formulation for the system is presented to enable design state feedback controller scheme. In this research, an optimal control system based on linear quadratic regulator (LQR) technique is proposed to stabilize the mobile robot. The LQR controller is designed to control the position and yaw rotation of the two-wheeled vehicle. The proposed balancing robot system is validated by simulating the LQR using Matlab software. Two tuning methods, genetic algorithm (GA) and bacteria foraging optimization algorithm (BFOA) are used to obtain optimal values for controller parameters. A comparison between the performance of both controllers GA-LQR and BFO-LQR is achieved based on the standard control criteria which includes rise time, maximum overshoot, settling time and control input of the system. Simulation results suggest that the BFOA-LQR controller can be adopted to balance the Segway robot with minimal overshoot and oscillation frequency

    On computing fixpoints in well-structured regular model checking, with applications to lossy channel systems

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    We prove a general finite convergence theorem for "upward-guarded" fixpoint expressions over a well-quasi-ordered set. This has immediate applications in regular model checking of well-structured systems, where a main issue is the eventual convergence of fixpoint computations. In particular, we are able to directly obtain several new decidability results on lossy channel systems.Comment: 16 page

    Reachability of Communicating Timed Processes

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    We study the reachability problem for communicating timed processes, both in discrete and dense time. Our model comprises automata with local timing constraints communicating over unbounded FIFO channels. Each automaton can only access its set of local clocks; all clocks evolve at the same rate. Our main contribution is a complete characterization of decidable and undecidable communication topologies, for both discrete and dense time. We also obtain complexity results, by showing that communicating timed processes are at least as hard as Petri nets; in the discrete time, we also show equivalence with Petri nets. Our results follow from mutual topology-preserving reductions between timed automata and (untimed) counter automata.Comment: Extended versio

    Review of Detection Denial of Service Attacks using Machine Learning through Ensemble Learning

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    Today's network hacking is more resource-intensive because the goal is to prohibit the user from using the network's resources when the target is either offensive or for financial gain, especially in businesses and organizations. That relies on the Internet like Amazon Due to this, several techniques, such as artificial intelligence algorithms like machine learning (ML) and deep learning (DL), have been developed to identify intrusion and network infiltration and discriminate between legitimate and unauthorized users. Application of machine learning and ensemble learning algorithms to various datasets, consideration of homogeneous ensembles using a single algorithm type or heterogeneous ensembles using several algorithm types, and evaluation of the discovery outcomes in terms of accuracy or discovery error for detecting attacks. The survey literature provides an overview of the many approaches and approaches of one or more machine-learning algorithms used in various datasets to identify denial of service attacks. It has also been shown that employing the hybrid approach is the most common and produces better attack detection outcomes than using the sole approaches. Numerous machine learning techniques, including support vector machines (SVM), K-Nearest Neighbors (KNN), and ensemble learning like random forest (RF), bagging, and boosting, are illustrated in this work (DT). That is employed in several articles to identify different denial of service (DoS) assaults, including the trojan horse, teardrop, land, smurf, flooding, and worm. That attacks network traffic and resources to deny users access to the resources or to steal confidential information from the company without damaging the system and employs several algorithms to obtain high attack detection accuracy and low false alarm rates

    Determinants of Tax Incentives and the Effect of Corporate Tax Rate on the Foreign Direct Investment

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    Corporate tax incentives are granted by governments to encourage foreign direct investment FDI. While the tax policy in Iraq varies for both domestic and foreign investments, the Iraqi government offers tax holidays between 3 to 10 years to attract foreign investors to do their desirable investments. The objective of this research is to analyze how Iraqi's corporate tax rate affects FDI, and study the comparison between Iraqi and KRG tax policies. The data are annual observations of the Iraqi tax rate which is the net percentage of profit, and FDI net percentage of GDP. The time-series data from 2005 to 2019 were employed. Three distinct sorts of tests are engaged in this research, the first stage unit root test is conducted to determine the stationary of the data, secondly, Johansen co-integration test was used to find co-integration between variables, and finally, the Granger Causation test is used to determine causality among variables over the period. The finding result shows that the tax rate and FDI are co-integrated and have a long-run relationship. Particularly, foreign direct investment is impacted by changes in the tax rate, while fluctuation in the number of FDI has not any influence on the tax rate

    Planning a Family:priorities and concerns in rural Tanzanmia

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    A fertility survey using qualitative and quantitative techniques described a high fertility setting (TFR 5.8) in southern Tanzania where family planning use was 16%. Current use was influenced by rising parity, educational level, age of last born child, breastfeeding status, a\ud preference for longer than the mean birth interval (32 months), not being related to the household head, and living in a house with a tin roof. Three principal concerns amongst women were outlined from the findings. First, that there is a large unmet need for family planning services in the area particularly among teenagers for whom it is associated with induced abortion. Second, that family planning is being used predominantly for spacing but fears\ud associated with it often curtail effective use. Third, that service provision is perceived to be lacking in two main areas — regularity of supply, and addressing rumours and fears associated with family planning. Reproductive health interventions in the area should ultimately be more\ud widespread and, in particular, abortion is highlighted as an urgent issue for further research.\ud The potential for a fast and positive impact is high, given the simplicity of the perceived needs of\ud women from this study. (Afr J Reprod Health 2004; 8[2]:111-123)\u

    Electronic Toll Collection System based on Radio Frequency Identification System

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    This papaer entitled electronic toll collection system based on Radio Frequncy Identification System explained in detail based on current issue at toll collection system. There are some obstacles faced every day where the users spent their valuable time in queue at tollgate due to traffic congestion as well as using traditional manual method in most existing toll ETC system to collect toll from road users. Besides that, the barrier design where each vehicle stop waiting until barrier lift which consider source of time delay. To tackle stated problems, an electronic toll collection system is proposed which based on RFID technology. The integrated system consists of two main sections, electronic sides where all input data received from while database management office is where all necessary information stored. To compare the current ETC system, in this research elaborated internet of things where all data transmit through cloud and then to the main office in real time. Not only that, there is some enhancement based on barrier design where, gate is remained open for all vehicles with sufficient tags without requiring to stop to eliminate time delay.By check system throughput compare to existing toll systems, various tests have been carried out in different method where proposed system throughput much higher percentage the current system

    Exploring multi-stakeholder perceptions of practice-related facilitators to optimising the quality of integration of regulated pharmacy technicians in community pharmacy in Ontario: A qualitative study

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    OBJECTIVES: The objective of this study was to investigate multi-stakeholder perceptions of practice-related facilitators to optimising the quality of Regulated Pharmacy Technician (RPT) integration into the community workforce in Ontario. Facilitators to incorporating technicians into the workflow and supporting their optimal scope of practice were explored. METHODS: A qualitative exploratory study comprising a series of one-to-one interviews using a piloted, semi-structured interview guide was conducted with four community pharmacy stakeholder groups; pharmacists, RPTs, pharmacy assistants and pharmacy owners. Interviews were conducted until saturation of themes. Verbatim transcripts were coded inductively using the software, NVivo v12 (QSR International) and general inductive analysis identified key findings. KEY FINDINGS: Twenty-seven interviews were conducted consisting of seven pharmacists, seven RPTs, eight assistants and five pharmacy owners working within community pharmacy and/or academia or hospital. All participants from every stakeholder group acknowledged that the promise of regulation of pharmacy technicians was unfulfilled in practice. Three major themes of practical significance were derived: (i) A viable business plan that incorporates RPT remuneration and ensures sustainability is a facilitator to fuller integration of RPTs, (ii) Planning the pharmacy workflow to support RPTs’ and pharmacists’ evolving scopes is a facilitator to RPT integration and (iii) Schedule planning to incorporate RPTs and appropriate staffing ratios in relation to prescription volume and pharmacy services allows for optimal utilisation of RPT skills and facilitates their integration. CONCLUSIONS: Achieving integration of RPTs into the business of a community pharmacy has educational, workplace and regulatory implications, requiring the effective engagement of all stakeholders in pharmacy
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