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Prof. Nikos Petrellis
Department of Electrical and Computer Engineering, University of Peloponnese, 26334 Patra, Greece

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0 Embedded Systems
0 Signal Processing
0 VLSI
0 FPGAs
0 Mixed analog/digital design

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Embedded Systems
Signal Processing

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Short Biography

Nikos Petrellis is an associate professor in the Electrical and Computer Engineering Department at the University of Peloponnese in Patras, Greece. He was with the University of Thessaly (former TEI of Thessaly) from 2010 to 2019. He has also served as adjunct faculty at the University of Patras and TEI of Mesolonghi from 2003 to 2010. He has worked for several companies, including Atmel Greece, Giga Hellas (Intel Corp.) and Analogies S.A. He has published more than 100 papers in peer-reviewed international journals and conference proceedings. He is the sole or main author of nine international and Greek patents. His research interests include the hardware/software codesign of embedded systems, reconfigurable hardware, VLSI, image and signal processing, ML and AI applications accelerated in hardware, the development of smart phone and cloud-based applications, and the IoT.

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Journal article
Published: 01 June 2021 in Electronics
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This work investigates the real-time performance of Linux kernels and distributions with a PREEMPT_RT real-time patch on ARM-based embedded devices. Experimental measurements, which are mainly based on heuristic methods, provide novel insights into Linux real-time performance on ARM-based embedded devices (e.g., BeagleBoard and RaspberryPi). Evaluations of the Linux real-time performance are based on specific real-time software measurement modules, developed for this purpose, and the use of a standard benchmark tool, cyclictest. Software modules were designed upon the introduction of a new response task model, an innovative aspect of this work. Measurements include the latency of response tasks at user and kernel space, the response on the execution of periodic tasks, the maximum sustained frequency and general latency performance metrics. The results show that in such systems the PREEMPT_RT patch provides more improved real-time performance than the default Linux kernels. The latencies and particularly the worst-case latencies are reduced with real-time support, thus making such devices running Linux with PREEMPT_RT more appropriate for use in time-sensitive embedded control systems and applications. Furthermore, the proposed performance measurements approach and evaluation methodology could be applied and deployed on other Linux-based real-time platforms.

ACS Style

George Adam; Nikos Petrellis; Lambros Doulos. Performance Assessment of Linux Kernels with PREEMPT_RT on ARM-Based Embedded Devices. Electronics 2021, 10, 1331 .

AMA Style

George Adam, Nikos Petrellis, Lambros Doulos. Performance Assessment of Linux Kernels with PREEMPT_RT on ARM-Based Embedded Devices. Electronics. 2021; 10 (11):1331.

Chicago/Turabian Style

George Adam; Nikos Petrellis; Lambros Doulos. 2021. "Performance Assessment of Linux Kernels with PREEMPT_RT on ARM-Based Embedded Devices." Electronics 10, no. 11: 1331.

Journal article
Published: 13 May 2021 in Applied Sciences
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Noninvasive morphological feature monitoring is essential in fish culture, since these features are currently measured manually with a high cost. These morphological parameters can concern the size or mass of the fish, or its health as indicated, for example, by the color of the eyes or the gills. Several approaches have been proposed, based either on image processing or machine learning techniques. In this paper, both of these approaches have been combined in a unified environment with novel techniques (e.g., edge or corner detection and pattern stretching) to estimate the fish’s relative length, height and the area it occupies in the image. The method can be extended to estimate the absolute dimensions if a pair of cameras is used for obscured or slanted fish. Moreover, important fish parts such as the caudal, spiny and soft dorsal, pelvic and anal fins are located. Four species popular in fish cultures have been studied: Dicentrarchus labrax (sea bass), Diplodus puntazzo, Merluccius merluccius (cod fish) and Sparus aurata (sea bream). Taking into consideration that there are no large public datasets for the specific species, the training and testing of the developed methods has been performed using 25 photographs per species. The fish length estimation error ranges between 1.9% and 13.2%, which is comparable to the referenced approaches that are trained with much larger datasets and do not offer the full functionality of the proposed method.

ACS Style

Nikos Petrellis. Measurement of Fish Morphological Features through Image Processing and Deep Learning Techniques. Applied Sciences 2021, 11, 4416 .

AMA Style

Nikos Petrellis. Measurement of Fish Morphological Features through Image Processing and Deep Learning Techniques. Applied Sciences. 2021; 11 (10):4416.

Chicago/Turabian Style

Nikos Petrellis. 2021. "Measurement of Fish Morphological Features through Image Processing and Deep Learning Techniques." Applied Sciences 11, no. 10: 4416.

Journal article
Published: 07 February 2021 in Computers
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Remote symptom tracking is critical for the prevention of Covid-19 spread. The qualified medical staff working in the call centers of primary health care units have to take critical decisions often based on vague information about the patient condition. The congestion and the medical protocols that are constantly changing often lead to incorrect decisions. The proposed platform allows the remote assessment of symptoms and can be useful for patients, health institutes and researchers. It consists of mobile desktop applications and medical sensors connected to cloud infrastructure. The unique features offered by the proposed solution are: (a) dynamic adaptation of Medical Protocols (MP) is supported (for the definition of alert rules, sensor sampling strategy and questionnaire structure) covering different medical cases (pre- or post-hospitalization, vulnerable population, etc.), (b) anonymous medical data can be statistically processed in the context of the research about an infection such as Covid-19, (c) reliable diagnosis is supported since several factors are taken into consideration, (d) the platform can be used to drastically reduce the congestion in various healthcare units. For the demonstration of (b), new classification methods based on similarity metrics have been tested for cough sound classification with an accuracy in the order of 90%.

ACS Style

Nikos Petrellis; George Adam. Symptom Tracking and Experimentation Platform for Covid-19 or Similar Infections. Computers 2021, 10, 22 .

AMA Style

Nikos Petrellis, George Adam. Symptom Tracking and Experimentation Platform for Covid-19 or Similar Infections. Computers. 2021; 10 (2):22.

Chicago/Turabian Style

Nikos Petrellis; George Adam. 2021. "Symptom Tracking and Experimentation Platform for Covid-19 or Similar Infections." Computers 10, no. 2: 22.

Journal article
Published: 05 December 2020 in Computers
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The progress of embedded control systems in the last several years has made possible the realization of highly-effective controllers in many domains. It is essential for such systems to provide effective performance at an affordable cost. Furthermore, real-time embedded control systems must have low energy consumption, as well as be reliable and timely. This research investigates primarily the feasibility of implementing an embedded real-time control system, based on a low-cost, commercially off-the-shelf (COTS) microcontroller platform. It explores real-time issues, such as the reliability and timely response, of such a system implementation. This work presents the development and performance evaluation of a novel real-time control architecture, based upon a BeagleBoard microcontroller, and applied into the PWM (pulse width modulation) control of a three-phase induction motor in a suction pump. The approach followed makes minimal use of general-purpose hardware (BeagleBone Black microcontroller board) and open-source software components (including Linux Operating System with PREEMPT_RT real-time support) for building a reliable real-time control system. The applicability of the proposed control system architecture is validated and evaluated in a real case study in manufacturing. The results provide sufficient evidence of the efficiency and reliability of the proposed approach into the development of a real-time control system based upon COTS components.

ACS Style

George K. Adam; Nikos Petrellis; Panagiotis A. Kontaxis; Tilemachos Stylianos. COTS-Based Real-Time System Development: An Effective Application in Pump Motor Control. Computers 2020, 9, 97 .

AMA Style

George K. Adam, Nikos Petrellis, Panagiotis A. Kontaxis, Tilemachos Stylianos. COTS-Based Real-Time System Development: An Effective Application in Pump Motor Control. Computers. 2020; 9 (4):97.

Chicago/Turabian Style

George K. Adam; Nikos Petrellis; Panagiotis A. Kontaxis; Tilemachos Stylianos. 2020. "COTS-Based Real-Time System Development: An Effective Application in Pump Motor Control." Computers 9, no. 4: 97.

Research reports research article
Published: 06 October 2020 in Digital Biomarkers
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Background: Contactless symptom tracking is essential for the diagnosis of COVID-19 cases that need hospitalization. Indications from sensors and user descriptions have to be combined in order to make the right decisions. Methods: The proposed multipurpose platform Coronario combines sensory information from different sources for a valid diagnosis following a dynamically adaptable protocol. The information exchanged can also be exploited for the advancement of research on COVID-19. The platform consists of mobile and desktop applications, sensor infrastructure, and cloud services. It may be used by patients in pre- and post-hospitalization stages, vulnerable populations, medical practitioners, and researchers. Results: The supported audio processing is used to demonstrate how the Coronario platform can assist research on the nature of COVID-19. Cough sounds are classified as a case study, with 90% accuracy. Discussion/Conclusions: The dynamic adaptation to new medical protocols is one of the main advantages of the developed platform, making it particularly useful for several target groups of patients that require different screening methods. A medical protocol determines the structure of the questionnaires, the medical sensor sampling strategy and, the alert rules.

ACS Style

Nikos Petrellis. A COVID-19 Multipurpose Platform. Digital Biomarkers 2020, 4, 89 -98.

AMA Style

Nikos Petrellis. A COVID-19 Multipurpose Platform. Digital Biomarkers. 2020; 4 (3):89-98.

Chicago/Turabian Style

Nikos Petrellis. 2020. "A COVID-19 Multipurpose Platform." Digital Biomarkers 4, no. 3: 89-98.

Journal article
Published: 06 May 2020 in Applied Sciences
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The challenge of keeping the development and implementation of real-time control systems reliable and efficient and at the same time, low-cost and low-energy, is getting harder. This is because system designers and developers are faced with the dependability, inflexibility and often high-cost of specialized or custom-built hardware and software components. This research attempts to tackle issues such as the reliability and efficiency of real-time control systems and advance further the current state-of-the-art. For this purpose, a strong emphasis is placed on finding novel efficient solutions based on standardized and commercially available off-the-shelf hardware/software components. In this direction, this research applies credible and feasible methodologies (e.g., model-based design, component-based design, formal verification, real-time scheduling, prototyping, and validation) in an innovative enhanced way. As an important outcome, a versatile integrative design approach and architectural framework (VIDAF) is proposed, which supports the development and implementation of reliable real-time control systems and applications using commercial off-the-shelf (COTS) components. The feasibility and applicability of the proposed system’s architecture are evaluated and validated through a system application in embedded real-time control in manufacturing. The research outcomes are expected to have a positive impact on emerging areas such as the Industrial Internet of Things (IIoT).

ACS Style

George K. Adam; Nikos Petrellis; Georgia Garani; Tilemachos Stylianos. COTS-Based Architectural Framework for Reliable Real-Time Control Applications in Manufacturing. Applied Sciences 2020, 10, 3228 .

AMA Style

George K. Adam, Nikos Petrellis, Georgia Garani, Tilemachos Stylianos. COTS-Based Architectural Framework for Reliable Real-Time Control Applications in Manufacturing. Applied Sciences. 2020; 10 (9):3228.

Chicago/Turabian Style

George K. Adam; Nikos Petrellis; Georgia Garani; Tilemachos Stylianos. 2020. "COTS-Based Architectural Framework for Reliable Real-Time Control Applications in Manufacturing." Applied Sciences 10, no. 9: 3228.

Journal article
Published: 03 April 2020 in Symmetry
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In this paper, we focus on Orthogonal Frequency Division Multiplexing (OFDM) transceivers where undersampling is employed by the receiver Analog/Digital Converter (ADC) when sparse information is exchanged. Several Fast Fourier Transform (FFT) symmetry properties are exploited to allow the substitution of specific input values by others that have already been sampled by the ADC. Several architectures have been proposed in the literature for efficient FFT implementations in terms of power, speed and hardware resources. The FFT input/output values, twiddle factors, etc., are complex numbers with their real and imaginary parts being represented using fixed point format. A tradeoff has to be made between rounding error and complexity. The optimal minimum FFT word length is investigated by combining the undersampling and the rounding error. A configurable new FFT architecture has been developed in hardware description language to test the error model with various FFT sizes, word lengths and Quadrature Amplitude Modulations (QAM). A system designer can take into account the sparseness of the input data and define the desired rounding and undersampling error relation. Τhe developed error model would then predict the required word length and ADC resolution with average Root Mean Square Error (RMSE) less than 1.

ACS Style

Nikos Petrellis. Selecting FFT Word Length for an OFDM Receiver That Supports Undersampling. Symmetry 2020, 12, 543 .

AMA Style

Nikos Petrellis. Selecting FFT Word Length for an OFDM Receiver That Supports Undersampling. Symmetry. 2020; 12 (4):543.

Chicago/Turabian Style

Nikos Petrellis. 2020. "Selecting FFT Word Length for an OFDM Receiver That Supports Undersampling." Symmetry 12, no. 4: 543.

Journal article
Published: 13 May 2019 in Applied Sciences
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A plant disease diagnosis method that can be implemented with the resources of a mobile phone application, that does not have to be connected to a remote server, is presented and evaluated on citrus diseases. It can be used both by amateur gardeners and by professional agriculturists for early detection of diseases. The features used are extracted from photographs of plant parts like leaves or fruits and include the color, the relative area and the number of the lesion spots. These classification features, along with additional information like weather metadata, form disease signatures that can be easily defined by the end user (e.g., an agronomist). These signatures are based on the statistical processing of a small number of representative training photographs. The extracted features of a test photograph are compared against the disease signatures in order to select the most likely disease. An important advantage of the proposed approach is that the diagnosis does not depend on the orientation, the scale or the resolution of the photograph. The experiments have been conducted under several light exposure conditions. The accuracy was experimentally measured between 70% and 99%. An acceptable accuracy higher than 90% can be achieved in most of the cases since the lesion spots can recognized interactively with high precision.

ACS Style

Nikos Petrellis. Plant Disease Diagnosis for Smart Phone Applications with Extensible Set of Diseases. Applied Sciences 2019, 9, 1952 .

AMA Style

Nikos Petrellis. Plant Disease Diagnosis for Smart Phone Applications with Extensible Set of Diseases. Applied Sciences. 2019; 9 (9):1952.

Chicago/Turabian Style

Nikos Petrellis. 2019. "Plant Disease Diagnosis for Smart Phone Applications with Extensible Set of Diseases." Applied Sciences 9, no. 9: 1952.

Conference paper
Published: 12 February 2019 in Communications in Computer and Information Science
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The recognition of plant diseases is a responsibility of professional agriculture engineers. Intelligent systems can assist plant disease diagnosis in the early stages with low cost. User descriptions and image comparison are exploited in some expert systems that are already available. More sophisticated techniques like the one presented in this paper are based on features extracted from the symptoms (e.g., lesions) of a plant disease that appear on the leaves, the fruits, etc. The color, the dimensions and the number of these lesion spots can be used in some cases to discriminate the disease that has mortified a plant. In this paper, we describe a smart phone application that measures the features of the plant lesions with higher than 90% precision. The accuracy in the recognition of grapevine or citrus diseases that have been used as case studies is higher than 70% in most of the cases using only 5 photographs for the definition of each disease. The most important advantage of the proposed method is that the set of the supported diseases can be easily extended by the end-user.

ACS Style

Nikos Petrellis. Techniques for Plant Disease Diagnosis Evaluated on a Windows Phone Platform. Communications in Computer and Information Science 2019, 148 -163.

AMA Style

Nikos Petrellis. Techniques for Plant Disease Diagnosis Evaluated on a Windows Phone Platform. Communications in Computer and Information Science. 2019; ():148-163.

Chicago/Turabian Style

Nikos Petrellis. 2019. "Techniques for Plant Disease Diagnosis Evaluated on a Windows Phone Platform." Communications in Computer and Information Science , no. : 148-163.

Journal article
Published: 02 February 2019 in Electronics
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The proliferation of Internet of Things (IoT) devices for patient monitoring has gained much attention in clinical care performance, proficient chronic disease management, and home caregiving. This work presents the design of efficient medical IoT sensor nodes (SNs) in terms of low-cost, low power-consumption, and increased data accuracy based on open-source platforms. The method utilizes a Sensor Controller (SC) within the IoT SN, which is capable of performing medical checks supporting a broad coverage of medical uses. A communication protocol has been developed for data and command exchange among SC, local gateways, and physicians’ or patients’ mobile devices (tablets, smart phones). The SC supports moving average window (MAW) and principle component analysis (PCA) filtering algorithms to capture data from the attached low-cost body sensors of different sampling profiles. Significant extensions in SN’s portability is achieved through energy consumption minimization based on the idle time gaps between sensors’ activations. SN’s components are either deactivated or set to low activity operation during these idle intervals. A medical case study is presented and the evaluated results show that the proposed SN can be incorporated into e-health platforms since it achieves comparable accuracy to its certified and high-cost commercial counterparts.

ACS Style

Nikos Petrellis; Michael Birbas; Fotios Gioulekas. On the Design of Low-Cost IoT Sensor Node for e-Health Environments. Electronics 2019, 8, 178 .

AMA Style

Nikos Petrellis, Michael Birbas, Fotios Gioulekas. On the Design of Low-Cost IoT Sensor Node for e-Health Environments. Electronics. 2019; 8 (2):178.

Chicago/Turabian Style

Nikos Petrellis; Michael Birbas; Fotios Gioulekas. 2019. "On the Design of Low-Cost IoT Sensor Node for e-Health Environments." Electronics 8, no. 2: 178.

Journal article
Published: 01 January 2019 in AIMS Electronics and Electrical Engineering
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ACS Style

Nikos Petrellis. Skin disorder diagnosis with ambiguity reduction assisted by lesion color adaptation. AIMS Electronics and Electrical Engineering 2019, 3, 290 -308.

AMA Style

Nikos Petrellis. Skin disorder diagnosis with ambiguity reduction assisted by lesion color adaptation. AIMS Electronics and Electrical Engineering. 2019; 3 (3):290-308.

Chicago/Turabian Style

Nikos Petrellis. 2019. "Skin disorder diagnosis with ambiguity reduction assisted by lesion color adaptation." AIMS Electronics and Electrical Engineering 3, no. 3: 290-308.

Review
Published: 09 July 2018 in Symmetry
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Image processing has been extensively used in various (human, animal, plant) disease diagnosis approaches, assisting experts to select the right treatment. It has been applied to both images captured from cameras of visible light and from equipment that captures information in invisible wavelengths (magnetic/ultrasonic sensors, microscopes, etc.). In most of the referenced diagnosis applications, the image is enhanced by various filtering methods and segmentation follows isolating the regions of interest. Classification of the input image is performed at the final stage. The disease diagnosis approaches based on these steps and the common methods are described. The features extracted from a plant/skin disease diagnosis framework developed by the author are used here to demonstrate various techniques adopted in the literature. The various metrics along with the available experimental conditions and results presented in the referenced approaches are also discussed. The accuracy achieved in the diagnosis methods that are based on image processing is often higher than 90%. The motivation for this review is to highlight the most common and efficient methods that have been employed in various disease diagnosis approaches and suggest how they can be used in similar or different applications.

ACS Style

Nikos Petrellis. A Review of Image Processing Techniques Common in Human and Plant Disease Diagnosis. Symmetry 2018, 10, 270 .

AMA Style

Nikos Petrellis. A Review of Image Processing Techniques Common in Human and Plant Disease Diagnosis. Symmetry. 2018; 10 (7):270.

Chicago/Turabian Style

Nikos Petrellis. 2018. "A Review of Image Processing Techniques Common in Human and Plant Disease Diagnosis." Symmetry 10, no. 7: 270.

Conference paper
Published: 01 July 2018 in 2018 41st International Conference on Telecommunications and Signal Processing (TSP)
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The Savitzky-Golay (SG) filtering is evaluated in a low cost e-health platform that has been recently presented by the authors. The sensors' precision is not guaranteed in such a low cost platform since these sensors are not medically certified. The accuracy of the sensor measurements has to be improved in order to have a reliable e-health platform. Filtering methods like moving average window (MAW), principal component analysis (PCA) and a simplified Kalman filter have already been used for smoothing and for sensor precision improvement. The comparison of these methods with SG filtering shows that the latter can offer a significant precision improvement without the problems offered by other methods like the latency of the MAW. More specifically, the SG filtering can offer an up to 10 times better Normalized Mean Square Error (NMSE) or 25dB higher Signal to Noise Ratio (SNR) than the original values. PCA on the other hand offers a remarkable precision improvement in many cases (e.g., half NMSE or 5dB better SNR) along with 20% compression that leads to lower power consumption.

ACS Style

Ioannis- Emmanouil Kosmadakis; Nikos Petrellis; Michael Birbas; Miltiadis Vardakas. Employing Savitzky-Golay Smoothing in a Low Cost eHealth Platform. 2018 41st International Conference on Telecommunications and Signal Processing (TSP) 2018, 1 -5.

AMA Style

Ioannis- Emmanouil Kosmadakis, Nikos Petrellis, Michael Birbas, Miltiadis Vardakas. Employing Savitzky-Golay Smoothing in a Low Cost eHealth Platform. 2018 41st International Conference on Telecommunications and Signal Processing (TSP). 2018; ():1-5.

Chicago/Turabian Style

Ioannis- Emmanouil Kosmadakis; Nikos Petrellis; Michael Birbas; Miltiadis Vardakas. 2018. "Employing Savitzky-Golay Smoothing in a Low Cost eHealth Platform." 2018 41st International Conference on Telecommunications and Signal Processing (TSP) , no. : 1-5.

Journal article
Published: 01 November 2016 in Measurement
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ACS Style

Nikos Petrellis. A low complexity digital unit for scalar linear interpolation and compression. Measurement 2016, 93, 288 -302.

AMA Style

Nikos Petrellis. A low complexity digital unit for scalar linear interpolation and compression. Measurement. 2016; 93 ():288-302.

Chicago/Turabian Style

Nikos Petrellis. 2016. "A low complexity digital unit for scalar linear interpolation and compression." Measurement 93, no. : 288-302.

Journal article
Published: 01 June 2016 in Image Processing & Communications
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The sub-sampling method for Orthogonal Frequency Division Multiplexing proposed recently, has been extended in this paper allowing the Analog-to-Digital Converter on the receiver side to operate in low power mode, up to 3/4 of the time. The predictability of the parity patterns generated by the Forward Error Correction encoder of the transmitter, when sparse data are exchanged, is exploited in order to define appropriate Inverse Fast Fourier Transform input symbol arrangements. These symbol arrangements allow the substitution of a number of samples by others that have already been received. Moreover, several operations of the Fast Fourier Transform can be omitted because their result is zero when identical values appear at its input. The advantages of the proposed method are: low power, higher speed and fewer memory resources. Despite other iterative sub-sampling approaches like Compressive Sampling, the proposed method is not iterative and thus it can be implemented with very low complexity hardware. The simulation results show that full input signal recovery or at least a very low Bit Error Rate is achieved in most of the cases that have been tested.

ACS Style

Nikos Petrellis. Sub-Sampling in OFDM with Constant Time Signal Recovery. Image Processing & Communications 2016, 21, 19 -32.

AMA Style

Nikos Petrellis. Sub-Sampling in OFDM with Constant Time Signal Recovery. Image Processing & Communications. 2016; 21 (2):19-32.

Chicago/Turabian Style

Nikos Petrellis. 2016. "Sub-Sampling in OFDM with Constant Time Signal Recovery." Image Processing & Communications 21, no. 2: 19-32.

Journal article
Published: 01 January 2016 in International Journal of Distributed Sensor Networks
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An undersampling technique appropriate for Orthogonal Frequency Division Multiplexing (OFDM) that can be implemented with low complexity hardware is presented. The OFDM receiver can operate in undersampling mode, 75% of the time. One of the advantages of the proposed scheme is the reduction down to the half of the power consumed by the Analog Digital Converter (ADC) and the Fast Fourier Transform (FFT). The FFT memory requirements for sample storage can also be reduced and its operating speed can be increased. Simulations were performed for two Quadrature Amplitude Modulation orders (16-QAM and 32-QAM), two options for the FFT size (1024 and 4096), two alternative input symbol structures for the inverse FFT (IFFT), and several sparseness levels and samples substitution options. The Symbol Error Rate (SER) and image reconstruction examples are used to show that a full reconstruction or a very low error can be achieved. Although the proposed undersampling method is evaluated for wired channel, it can also be used without any modification to wireless Single Input Single Output (SISO) systems (with an expected SER degradation). It can also be used with Multiple Input Multiple Output (MIMO) systems when an appropriate arrangement of the IFFT input symbols is adopted.

ACS Style

Nikos Petrellis. Low Power OFDM Receiver Exploiting Data Sparseness and DFT Symmetry. International Journal of Distributed Sensor Networks 2016, 12, 1 .

AMA Style

Nikos Petrellis. Low Power OFDM Receiver Exploiting Data Sparseness and DFT Symmetry. International Journal of Distributed Sensor Networks. 2016; 12 (1):1.

Chicago/Turabian Style

Nikos Petrellis. 2016. "Low Power OFDM Receiver Exploiting Data Sparseness and DFT Symmetry." International Journal of Distributed Sensor Networks 12, no. 1: 1.

Conference paper
Published: 01 October 2015 in Proceedings of the 19th Panhellenic Conference on Informatics
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The continuous growing of the percentage of elderly people in total population the last decades has given significant boost to ehealth technology and applications that allow for the remote health monitoring of aging people, thus acting as a remedy to the explosive costs that would be otherwise needed for full medical coverage. In this context, we present in this paper an efficient ehealth platform based on a low-cost medical sensor controller system, the main features of which have been successfully enhanced in terms of flexibility, accuracy and power consumption so as to be able to provide wide coverage of tests/medical scenarios with the best possible reliability and low power consumption. A low-cost sensor controller capable of performing both simple and more advanced tests with increased accuracy forms the core of the system communicating with a Gateway installed in the patient's residence and a tablet or smart phone used for giving instructions to the patient by the medical supervisors. Appropriate processing and filtering algorithms are applied where necessary to enhance the accuracy of sensor measurements achieving substantial improvements close to the level of high-cost commercial ones. Furthermore, a combination of hardware and software techniques are employed which exploit at the best possible extent the idle intervals between measurements resulting in considerably lower power requirements and extension of the platform's portability.

ACS Style

Nikos Petrellis; Michael K. Birbas; Fotios Gioulekas. Precision and power issues in a medical sensor controller. Proceedings of the 19th Panhellenic Conference on Informatics 2015, 171 -176.

AMA Style

Nikos Petrellis, Michael K. Birbas, Fotios Gioulekas. Precision and power issues in a medical sensor controller. Proceedings of the 19th Panhellenic Conference on Informatics. 2015; ():171-176.

Chicago/Turabian Style

Nikos Petrellis; Michael K. Birbas; Fotios Gioulekas. 2015. "Precision and power issues in a medical sensor controller." Proceedings of the 19th Panhellenic Conference on Informatics , no. : 171-176.

Conference paper
Published: 16 September 2015 in Journal of Physics: Conference Series
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Aging population can benefit from health care systems that allow their health and daily life to be monitored by expert medical staff. Blood pressure, temperature measurements or more advanced tests like Electrocardiograms (ECG) can be ordered through such a healthcare system while urgent situations can be detected and alleviated on time. The results of these tests can be stored with security in a remote cloud or database. Such systems are often used to monitor non-life threatening patient health problems and their advantage in lowering the cost of the healthcare services is obvious. A low cost commercial medical sensor kit has been used in the present work, trying to improve the accuracy and stability of the sensor measurements, the power consumption, etc. This Sensor Controller communicates with a Gateway installed in the patient's residence and a tablet or smart phone used for giving instructions to the patient through a comprehensive user interface. A flexible communication protocol has been defined supporting any short or long term sensor sampling scenario. The experimental results show that it is possible to achieve low power consumption by applying apropriate sleep intervals to the Sensor Controller and by deactivating periodically some of its functionality.

ACS Style

M Birbas; N Petrellis; Fotios Gioulekas. A Low Cost Sensor Controller for Health Monitoring. Journal of Physics: Conference Series 2015, 637, 012021 .

AMA Style

M Birbas, N Petrellis, Fotios Gioulekas. A Low Cost Sensor Controller for Health Monitoring. Journal of Physics: Conference Series. 2015; 637 (1):012021.

Chicago/Turabian Style

M Birbas; N Petrellis; Fotios Gioulekas. 2015. "A Low Cost Sensor Controller for Health Monitoring." Journal of Physics: Conference Series 637, no. 1: 012021.

Conference paper
Published: 01 January 2014 in Proceedings of the 4th International Conference on Wireless Mobile Communication and Healthcare - "Transforming healthcare through innovations in mobile and wireless technologies"
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ACS Style

Nikos Petrellis. A Scalar Interpolator/Compressor for the Improvement of Sensor Linearity. Proceedings of the 4th International Conference on Wireless Mobile Communication and Healthcare - "Transforming healthcare through innovations in mobile and wireless technologies" 2014, 1 .

AMA Style

Nikos Petrellis. A Scalar Interpolator/Compressor for the Improvement of Sensor Linearity. Proceedings of the 4th International Conference on Wireless Mobile Communication and Healthcare - "Transforming healthcare through innovations in mobile and wireless technologies". 2014; ():1.

Chicago/Turabian Style

Nikos Petrellis. 2014. "A Scalar Interpolator/Compressor for the Improvement of Sensor Linearity." Proceedings of the 4th International Conference on Wireless Mobile Communication and Healthcare - "Transforming healthcare through innovations in mobile and wireless technologies" , no. : 1.

Journal article
Published: 30 December 2011 in Microelectronics Journal
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Current Mirrors are widely used in current mode circuits like A/D Converters, current conveyors, filters etc. The most important features of a current mirror are its precision, its input and output, resistance and minimum voltage and its frequency response. Although several mirrors with extremely small current transfer error have been presented, this error is usually measured in the typical case. This error may significantly differ in real-time conditions depending on mismatches, process and temperature variations. Stimulated by the current reference generation required in an A/D Converter with novel binary tree architecture that has been recently presented, an appropriate current mirror architecture supported by real time calibration logic is described in this paper. This mirror can generate a high enough output current (up to 1 mA), with relatively low transfer error (<4%), in a descent frequency range of up to 1 GHz. It requires a 1–1.2 V voltage supply and dissipates a power that can be as low as 0.3 mW. The error is measured using mismatch and process variation Monte Carlo post-layout simulations in TSMC 90 nm process.

ACS Style

Nikos Petrellis; George Adam; Dimitrios Ventzas. A real-time self-calibrated current mirror for wide range current reference generation, signal reproduction and delaying. Microelectronics Journal 2011, 43, 225 -234.

AMA Style

Nikos Petrellis, George Adam, Dimitrios Ventzas. A real-time self-calibrated current mirror for wide range current reference generation, signal reproduction and delaying. Microelectronics Journal. 2011; 43 (3):225-234.

Chicago/Turabian Style

Nikos Petrellis; George Adam; Dimitrios Ventzas. 2011. "A real-time self-calibrated current mirror for wide range current reference generation, signal reproduction and delaying." Microelectronics Journal 43, no. 3: 225-234.