Dan Necsulescu - Academia.edu (original) (raw)
Papers by Dan Necsulescu
In the era of the Internet of Things (IoT), it is crucial to study the real-time dependencies of ... more In the era of the Internet of Things (IoT), it is crucial to study the real-time dependencies of the Web, its failures, and the time delays. Wireless links widen the domain of applications of mixed, engineered systems such that computer integration includes remote nodes that are not wired to a central station. System integration requires addressing, monitoring and control issues resulting from link uncertainty. The performance of a real-time control system depends not only on the reliability of the hardware and software used but also on the time delay in estimating the output, because of the effects of computing time delay on the control system performance. New solutions are required based on distributed model predictive control, inverse problem solutions, and fractional order modeling. Remote monitoring and control contain wireless sensors and actuator networks that are stand-alone or embedded in an Internet of Things system. The focus of the paper is on enhancing continuity of ope...
In this paper is presented an approach for fire detection and estimation robots. The approach is ... more In this paper is presented an approach for fire detection and estimation robots. The approach is based on type-2 fuzzy logic system that utilizes measured temperature and light intensity to detect fires of various intensities at different distances. Type-2 fuzzy logic system (T2 FLS) is known for not needing exact mathematic model and for its capability to handle more complicated uncertain situations compared with Type-1 fuzzy logic system (T1 FLS). Due to lack of expertise for new facilities, a new approach for training experts’ expertise and setting up T2 FLS parameters from pure data is discussed and simulated in this paper.
In this paper, an approach for human-following robot control is investigated. The approach is bas... more In this paper, an approach for human-following robot control is investigated. The approach is based on velocity potential fields that permit to generate velocity vector commands that drive the robot at a safe distance with regard to the human while avoiding obstacles. Velocity potential fields are known for not crating local minima present in the case of artificial potential fields. The approach is first formulated and illustrated for a robot moving toward a fixed goal while avoiding two close-by obstacles without being stopped in a local minimum. For achieving a safe stop at the goal. A quasi-harmonic control law is proposed. Next, for the same environment, the approach is formulated and simulated for a robot following a human.
SAE International Journal of Passenger Cars - Electronic and Electrical Systems, 2019
IEEE Transactions on Industrial Electronics, 2018
Linear transform has been widely used in time-frequency analysis of rotational machine vibration.... more Linear transform has been widely used in time-frequency analysis of rotational machine vibration. However, the linear transform and its variants in current forms cannot be used to reliably analyze rotational machinery vibration signals under non-stationary conditions because of their smear effect and limited time-variability in time-frequency resolution. As such, this paper proposes a new time-frequency method, named velocity synchronous linear chirplet transform (VSLCT). The proposed VSLCT is an extended version of the current linear transform. It can effectively alleviate the smear effect and can dynamically provide desirable time-frequency resolution in response to condition variations. The smearing problem is resolved by using linear chirplet bases with frequencies synchronous with shaft rotational velocity, and the time-frequency resolution is made responsive to signal condition changes using time-varying window lengths. To successfully implement the VSLCT, a kurtosis-guided approach is proposed to dynamically determine the two time-varying parameters, i.e., window length and normalized angle. Therefore, the VSLCT does not require the user to provide such parameters and hence avoids the subjectivity and bias of human judgment that is often time-consuming and knowledge-demanding. This method can also analyze normal mono-component frequency-modulated signal.
Proceedings of the 3rd International Conference of Control, Dynamic Systems, and Robotics (CDSR'16), 2016
In this paper is investigated the control of the temperature on one side of the plate from the op... more In this paper is investigated the control of the temperature on one side of the plate from the opposite side. To solve this problem, Laplace transform is used to obtain the quadrupole model of the direct heat equation and the analytical solution for the transfer function for the inverse problem. The resulting hyperbolic functions are approximated by Taylor expansions and the real-time open loop temperature control to a desired value is formulated. This approach is different from previous regularization methods of ill-posed problem and is suitable for real-time temperature control. Simulation results show the advantages and limitations of using inverse problem to control temperature of a plate.
In this paper, a human friendly autonomous robot, was presented. Navigation of this robot applies... more In this paper, a human friendly autonomous robot, was presented. Navigation of this robot applies sensor fusion technique based on Dempster-Shafer method and velocity potential field. The controller of the autonomous mobile robot is designed to lead the robot toward the goal while avoiding collisions in complex environments and maintain human safety as a first priority. The approach is based on Dempster-Shafer sensor fusion of signals from sonar and passive infrared sensors to allow the robot to identify human presence. A velocity potential field robot controller is formulated for the case of avoiding collisions while giving higher priority to collision avoidance with humans as opposed of objects. Simulations and experiments illustrate the performance of the approach in extreme situations. Keywordshuman friendly robots; Dempster-Shafer evidence theory; sensor fusion; human safety.
Proceedings of the 12th International Conference on Informatics in Control, Automation and Robotics, 2015
This paper addresses an ongoing research on a novel approach to Simultaneous Localization and Map... more This paper addresses an ongoing research on a novel approach to Simultaneous Localization and Mapping problem called Unscented HybridSLAM. The main contribution of this paper is to develop the map update formulas along with proof results in order to investigate the validation of the map evolution. The investigation is presented using the help of simulations in terms of robustness, map fusion, and the update process. Results clearly show that as the vehicle travels along the path and the map evolves, the Unscented HybridSLAM algorithm avoids the overestimation of landmarks.
Blindness affects the perception of the surrounding environmental conditions. The primary require... more Blindness affects the perception of the surrounding environmental conditions. The primary requirement of any visual aid for mobility is obstacle detection. This work proposes an indoor navigation system for the visually impaired people. The system presented in this study is a robust, independent and portable aid to assist the user to navigate with auditory guidance. Computer-based algorithms developed in C sharp for the Microsoft Xbox Kinect 360 sensor allows to build a device for the navigational purpose. Kinect sensor streams both colour and depth data from the surrounding environment in real-time, which is then processed to provide the user with directional feedback using the wireless earphones. The effectiveness of the system was tested in experiments conducted with six blindfolded volunteers who successfully navigated across various indoor locations. Moreover, the user could also follow a specific individual through the output generated from the processed images.
Proceedings of the 4th International Conference of Control, Dynamic Systems, and Robotics (CDSR'17), 2017
This thesis has been a challenging and wonderful journey. I take this opportunity to firstly than... more This thesis has been a challenging and wonderful journey. I take this opportunity to firstly thank Faculty of Engineering, University of Ottawa for giving me this opportunity. Such an endeavor would not have been possible without the much-appreciated help and support of every single person in my life has provided. I would like to express my gratitude to my supervisor Dr. Dan Necsulescu whose continuous guidance, encouragement and support made it possible for me to finish this work and helped me improve different aspects of this thesis. I would also like to especially thank Dr. Natalie Baddour for her valuable comments and ideas for further improvement of this thesis work. Also, I would like to express my thanks to Leo Denner who helped me with setting up the apparatus for my experimental work. Further, I would like to thank my Father, his blessings made me reach here, he provided me all the strength, courage, guidance and the environment to grow which led my interest in the research field. Mom has been my backbone, my inspiration, she has provided me with all the strength. And further, I would thank my loving sister who has been there for me whenever I needed her.
Proceedings of the 13th International Conference on Informatics in Control, Automation and Robotics, 2016
In this paper the temperature at one side of a plate is used to control in closed loop the temper... more In this paper the temperature at one side of a plate is used to control in closed loop the temperature on the opposite side of the plate. To solve this problem, Laplace transform is used to obtain the quadrupole model of the direct heat equation and the analytical solution for the transfer function for the inverse problem. The resulting hyperbolic functions are approximated by Taylor expansions to facilitate the real-time closed loop temperature control formulation. Simulation results illustrate the advantages and permit to identify the limitations of using inverse problem to closed loop control temperature of a plate.
2011 19th Mediterranean Conference on Control & Automation (MED), 2011
Index Terms—Non destructive testing; Fault diagnosis; Ex- periment design; Parameters predetermin... more Index Terms—Non destructive testing; Fault diagnosis; Ex- periment design; Parameters predetermination; Modeling & simulation. Abstract—We analyse heat conduction in a slab with imposed persistent oscillating temperature. Fourier series and periodic time varying solutions are derived by using separation of variables techniques. The analysis is aimed at assessing the limits of applicability of the simplified analytical model derived in (1) under the hypothesis of semi-infinite spatial domain. Such model allows for parameters predetermination in the design of experiments related with nondestructive tests for defects detection and failure prediction. The effect of the finite length of the specimen is investigated, therefore setting the foundation for experimental investigation of nondestructive damage detec- tion with infrared active thermography with boundary effects accounted for. simple formula that relates the frequency of the excitation with the amplitude of the temperature profile at a certain point in the domain. In this paper we want to asses the limitations of such simplified model by deriving analyti- cal series solutions of the initial-boundary-values problem associated with the heat conduction in a finite bar with one extreme exposed to periodic time varying excitation. Findings of the simplified model in (1) are also compared with numerical solutions obtained with the commercial finite element software ANSYS TM . Closed form expressions to evaluate the error introduced by discarding the finite length of the domain are derived. The analytical analysis is carried out by (i) using Fourier series projection which accounts for the transient time solution, and (ii) by assuming that the steady-state solution in the time domain due to a purely periodical persistent excitation is periodical with amplitude characterized by the properties of the space differential operator in the governing equation. Analytical models are useful in assessing the validity of the simplified model in (1), and to design non destructive testing experiments when the semi-infinite domain hypothesis is not applicable. The rest of the paper is organized as follows. In Section II we derive analytical solutions that can be used for design of our experimental setup, and to assess the validity range and limitations of the model in (1). Comparisons between the analytical and the numerical solutions in finite domain versus the solution in the semi-infinite domain are shown in Section III, and the effect of the finite length of the domain in the experimental setup is investigated. Conclusions and future research directions are discussed in Section IV. II. ANALYTICAL INVESTIGATION IN A FINITE DOMAIN
2012 IEEE International Instrumentation and Measurement Technology Conference Proceedings, 2012
ABSTRACT Infrared cameras working in the range of long wave infrared region from 8 to 14 µm are u... more ABSTRACT Infrared cameras working in the range of long wave infrared region from 8 to 14 µm are used in fever screening. An algorithm to automatically detect human subjects with fever in infrared images is presented in this paper. The algorithm was tested on a training data population to obtain a decision threshold in the framework of Neyman-Pearson hypothesis testing. Results show a high detection frequency. The algorithm is illustrated by testing it with simulated images and with images acquired by an infrared camera system. Several relevant scenarios involving different radiating objects in the field of the camera were reproduced and tested.
Proceedings of the 11th International Conference on Informatics in Control, Automation and Robotics, 2014
Autonomous robots can be equipped to detect potential threats of fire and find out the source whi... more Autonomous robots can be equipped to detect potential threats of fire and find out the source while avoiding the obstacles during navigation. The proposed system uses Voting Logic Fusion to approach and declare a potential fire source autonomously. The robot follows the increasing gradient of light and heat to identify the threat and approach source.
Proceedings of the 11th International Conference on Informatics in Control, Automation and Robotics, 2014
The inverse heat conduction in a multi-material slab with periodic temperature excitation is inve... more The inverse heat conduction in a multi-material slab with periodic temperature excitation is investigated. We derive a polynomial relation to estimate the frequency of the periodic excitation as a function of the temperature amplitude at a given observation point in the material specimen. The formula includes characteristic geometric and material parameters of the system. The polynomial formula can be an effective design tool for quick frequency predetermination in the design of non-destructive testing experiments with infrared thermography. The convergence and accuracy of the formula are assessed by comparison with analytical thermal quadrupoles solution.
In the era of the Internet of Things (IoT), it is crucial to study the real-time dependencies of ... more In the era of the Internet of Things (IoT), it is crucial to study the real-time dependencies of the Web, its failures, and the time delays. Wireless links widen the domain of applications of mixed, engineered systems such that computer integration includes remote nodes that are not wired to a central station. System integration requires addressing, monitoring and control issues resulting from link uncertainty. The performance of a real-time control system depends not only on the reliability of the hardware and software used but also on the time delay in estimating the output, because of the effects of computing time delay on the control system performance. New solutions are required based on distributed model predictive control, inverse problem solutions, and fractional order modeling. Remote monitoring and control contain wireless sensors and actuator networks that are stand-alone or embedded in an Internet of Things system. The focus of the paper is on enhancing continuity of ope...
In this paper is presented an approach for fire detection and estimation robots. The approach is ... more In this paper is presented an approach for fire detection and estimation robots. The approach is based on type-2 fuzzy logic system that utilizes measured temperature and light intensity to detect fires of various intensities at different distances. Type-2 fuzzy logic system (T2 FLS) is known for not needing exact mathematic model and for its capability to handle more complicated uncertain situations compared with Type-1 fuzzy logic system (T1 FLS). Due to lack of expertise for new facilities, a new approach for training experts’ expertise and setting up T2 FLS parameters from pure data is discussed and simulated in this paper.
In this paper, an approach for human-following robot control is investigated. The approach is bas... more In this paper, an approach for human-following robot control is investigated. The approach is based on velocity potential fields that permit to generate velocity vector commands that drive the robot at a safe distance with regard to the human while avoiding obstacles. Velocity potential fields are known for not crating local minima present in the case of artificial potential fields. The approach is first formulated and illustrated for a robot moving toward a fixed goal while avoiding two close-by obstacles without being stopped in a local minimum. For achieving a safe stop at the goal. A quasi-harmonic control law is proposed. Next, for the same environment, the approach is formulated and simulated for a robot following a human.
SAE International Journal of Passenger Cars - Electronic and Electrical Systems, 2019
IEEE Transactions on Industrial Electronics, 2018
Linear transform has been widely used in time-frequency analysis of rotational machine vibration.... more Linear transform has been widely used in time-frequency analysis of rotational machine vibration. However, the linear transform and its variants in current forms cannot be used to reliably analyze rotational machinery vibration signals under non-stationary conditions because of their smear effect and limited time-variability in time-frequency resolution. As such, this paper proposes a new time-frequency method, named velocity synchronous linear chirplet transform (VSLCT). The proposed VSLCT is an extended version of the current linear transform. It can effectively alleviate the smear effect and can dynamically provide desirable time-frequency resolution in response to condition variations. The smearing problem is resolved by using linear chirplet bases with frequencies synchronous with shaft rotational velocity, and the time-frequency resolution is made responsive to signal condition changes using time-varying window lengths. To successfully implement the VSLCT, a kurtosis-guided approach is proposed to dynamically determine the two time-varying parameters, i.e., window length and normalized angle. Therefore, the VSLCT does not require the user to provide such parameters and hence avoids the subjectivity and bias of human judgment that is often time-consuming and knowledge-demanding. This method can also analyze normal mono-component frequency-modulated signal.
Proceedings of the 3rd International Conference of Control, Dynamic Systems, and Robotics (CDSR'16), 2016
In this paper is investigated the control of the temperature on one side of the plate from the op... more In this paper is investigated the control of the temperature on one side of the plate from the opposite side. To solve this problem, Laplace transform is used to obtain the quadrupole model of the direct heat equation and the analytical solution for the transfer function for the inverse problem. The resulting hyperbolic functions are approximated by Taylor expansions and the real-time open loop temperature control to a desired value is formulated. This approach is different from previous regularization methods of ill-posed problem and is suitable for real-time temperature control. Simulation results show the advantages and limitations of using inverse problem to control temperature of a plate.
In this paper, a human friendly autonomous robot, was presented. Navigation of this robot applies... more In this paper, a human friendly autonomous robot, was presented. Navigation of this robot applies sensor fusion technique based on Dempster-Shafer method and velocity potential field. The controller of the autonomous mobile robot is designed to lead the robot toward the goal while avoiding collisions in complex environments and maintain human safety as a first priority. The approach is based on Dempster-Shafer sensor fusion of signals from sonar and passive infrared sensors to allow the robot to identify human presence. A velocity potential field robot controller is formulated for the case of avoiding collisions while giving higher priority to collision avoidance with humans as opposed of objects. Simulations and experiments illustrate the performance of the approach in extreme situations. Keywordshuman friendly robots; Dempster-Shafer evidence theory; sensor fusion; human safety.
Proceedings of the 12th International Conference on Informatics in Control, Automation and Robotics, 2015
This paper addresses an ongoing research on a novel approach to Simultaneous Localization and Map... more This paper addresses an ongoing research on a novel approach to Simultaneous Localization and Mapping problem called Unscented HybridSLAM. The main contribution of this paper is to develop the map update formulas along with proof results in order to investigate the validation of the map evolution. The investigation is presented using the help of simulations in terms of robustness, map fusion, and the update process. Results clearly show that as the vehicle travels along the path and the map evolves, the Unscented HybridSLAM algorithm avoids the overestimation of landmarks.
Blindness affects the perception of the surrounding environmental conditions. The primary require... more Blindness affects the perception of the surrounding environmental conditions. The primary requirement of any visual aid for mobility is obstacle detection. This work proposes an indoor navigation system for the visually impaired people. The system presented in this study is a robust, independent and portable aid to assist the user to navigate with auditory guidance. Computer-based algorithms developed in C sharp for the Microsoft Xbox Kinect 360 sensor allows to build a device for the navigational purpose. Kinect sensor streams both colour and depth data from the surrounding environment in real-time, which is then processed to provide the user with directional feedback using the wireless earphones. The effectiveness of the system was tested in experiments conducted with six blindfolded volunteers who successfully navigated across various indoor locations. Moreover, the user could also follow a specific individual through the output generated from the processed images.
Proceedings of the 4th International Conference of Control, Dynamic Systems, and Robotics (CDSR'17), 2017
This thesis has been a challenging and wonderful journey. I take this opportunity to firstly than... more This thesis has been a challenging and wonderful journey. I take this opportunity to firstly thank Faculty of Engineering, University of Ottawa for giving me this opportunity. Such an endeavor would not have been possible without the much-appreciated help and support of every single person in my life has provided. I would like to express my gratitude to my supervisor Dr. Dan Necsulescu whose continuous guidance, encouragement and support made it possible for me to finish this work and helped me improve different aspects of this thesis. I would also like to especially thank Dr. Natalie Baddour for her valuable comments and ideas for further improvement of this thesis work. Also, I would like to express my thanks to Leo Denner who helped me with setting up the apparatus for my experimental work. Further, I would like to thank my Father, his blessings made me reach here, he provided me all the strength, courage, guidance and the environment to grow which led my interest in the research field. Mom has been my backbone, my inspiration, she has provided me with all the strength. And further, I would thank my loving sister who has been there for me whenever I needed her.
Proceedings of the 13th International Conference on Informatics in Control, Automation and Robotics, 2016
In this paper the temperature at one side of a plate is used to control in closed loop the temper... more In this paper the temperature at one side of a plate is used to control in closed loop the temperature on the opposite side of the plate. To solve this problem, Laplace transform is used to obtain the quadrupole model of the direct heat equation and the analytical solution for the transfer function for the inverse problem. The resulting hyperbolic functions are approximated by Taylor expansions to facilitate the real-time closed loop temperature control formulation. Simulation results illustrate the advantages and permit to identify the limitations of using inverse problem to closed loop control temperature of a plate.
2011 19th Mediterranean Conference on Control & Automation (MED), 2011
Index Terms—Non destructive testing; Fault diagnosis; Ex- periment design; Parameters predetermin... more Index Terms—Non destructive testing; Fault diagnosis; Ex- periment design; Parameters predetermination; Modeling & simulation. Abstract—We analyse heat conduction in a slab with imposed persistent oscillating temperature. Fourier series and periodic time varying solutions are derived by using separation of variables techniques. The analysis is aimed at assessing the limits of applicability of the simplified analytical model derived in (1) under the hypothesis of semi-infinite spatial domain. Such model allows for parameters predetermination in the design of experiments related with nondestructive tests for defects detection and failure prediction. The effect of the finite length of the specimen is investigated, therefore setting the foundation for experimental investigation of nondestructive damage detec- tion with infrared active thermography with boundary effects accounted for. simple formula that relates the frequency of the excitation with the amplitude of the temperature profile at a certain point in the domain. In this paper we want to asses the limitations of such simplified model by deriving analyti- cal series solutions of the initial-boundary-values problem associated with the heat conduction in a finite bar with one extreme exposed to periodic time varying excitation. Findings of the simplified model in (1) are also compared with numerical solutions obtained with the commercial finite element software ANSYS TM . Closed form expressions to evaluate the error introduced by discarding the finite length of the domain are derived. The analytical analysis is carried out by (i) using Fourier series projection which accounts for the transient time solution, and (ii) by assuming that the steady-state solution in the time domain due to a purely periodical persistent excitation is periodical with amplitude characterized by the properties of the space differential operator in the governing equation. Analytical models are useful in assessing the validity of the simplified model in (1), and to design non destructive testing experiments when the semi-infinite domain hypothesis is not applicable. The rest of the paper is organized as follows. In Section II we derive analytical solutions that can be used for design of our experimental setup, and to assess the validity range and limitations of the model in (1). Comparisons between the analytical and the numerical solutions in finite domain versus the solution in the semi-infinite domain are shown in Section III, and the effect of the finite length of the domain in the experimental setup is investigated. Conclusions and future research directions are discussed in Section IV. II. ANALYTICAL INVESTIGATION IN A FINITE DOMAIN
2012 IEEE International Instrumentation and Measurement Technology Conference Proceedings, 2012
ABSTRACT Infrared cameras working in the range of long wave infrared region from 8 to 14 µm are u... more ABSTRACT Infrared cameras working in the range of long wave infrared region from 8 to 14 µm are used in fever screening. An algorithm to automatically detect human subjects with fever in infrared images is presented in this paper. The algorithm was tested on a training data population to obtain a decision threshold in the framework of Neyman-Pearson hypothesis testing. Results show a high detection frequency. The algorithm is illustrated by testing it with simulated images and with images acquired by an infrared camera system. Several relevant scenarios involving different radiating objects in the field of the camera were reproduced and tested.
Proceedings of the 11th International Conference on Informatics in Control, Automation and Robotics, 2014
Autonomous robots can be equipped to detect potential threats of fire and find out the source whi... more Autonomous robots can be equipped to detect potential threats of fire and find out the source while avoiding the obstacles during navigation. The proposed system uses Voting Logic Fusion to approach and declare a potential fire source autonomously. The robot follows the increasing gradient of light and heat to identify the threat and approach source.
Proceedings of the 11th International Conference on Informatics in Control, Automation and Robotics, 2014
The inverse heat conduction in a multi-material slab with periodic temperature excitation is inve... more The inverse heat conduction in a multi-material slab with periodic temperature excitation is investigated. We derive a polynomial relation to estimate the frequency of the periodic excitation as a function of the temperature amplitude at a given observation point in the material specimen. The formula includes characteristic geometric and material parameters of the system. The polynomial formula can be an effective design tool for quick frequency predetermination in the design of non-destructive testing experiments with infrared thermography. The convergence and accuracy of the formula are assessed by comparison with analytical thermal quadrupoles solution.