Publications
551 results found
Salaoru I, Prodromakis T, Khiat A, et al., 2013, Resistive switching of oxygen enhanced TiO<sub>2</sub> thin-film devices, APPLIED PHYSICS LETTERS, Vol: 102, ISSN: 0003-6951
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- Citations: 50
Premanode B, Toumazou C, 2013, Improving prediction of exchange rates using Differential EMD, EXPERT SYSTEMS WITH APPLICATIONS, Vol: 40, Pages: 377-384, ISSN: 0957-4174
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- Citations: 51
Trantidou T, Tariq M, Chang Y-C, et al., 2013, Free-standing Parylene C Thin Films As Flexible pH Sensing Membranes, 12th IEEE Sensors Conference, Publisher: IEEE, Pages: 1827-1830, ISSN: 1930-0395
Berdan R, Prodromakis T, Khiat A, et al., 2013, Temporal Processing with Volatile Memristors, IEEE International Symposium on Circuits and Systems (ISCAS), Publisher: IEEE, Pages: 425-428, ISSN: 0271-4302
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- Citations: 4
Sohbati M, Georgiou P, Toumazou C, 2013, A Piecewise Linear Approximating ISFET Readout, IEEE Biomedical Circuits and Systems Conference (BioCAS), Publisher: IEEE, Pages: 37-40, ISSN: 2163-4025
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- Citations: 3
Sohbati M, Georgiou P, Toumazou C, 2013, REFET Replication for ISFET-based SNP Detection Arrays, IEEE International Symposium on Circuits and Systems (ISCAS), Publisher: IEEE, Pages: 185-188, ISSN: 0271-4302
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- Citations: 6
Eftekhar A, Toumazou C, Drakakis EM, 2013, Empirical Mode Decomposition: Real-Time Implementation and Applicationss, Journal of Signal Processing Systems, Vol: 73, Pages: 43-58, ISSN: 1939-8018
Herrero P, Georgiou P, Oliver N, et al., 2013, In-Silico Comparison of a Bio-Inspired Glucose Controller vs. a PID controller with Insulin Feedback, Advanced Technologies & Treatments for Diabetes (ATTD)
A recently developed bio-inspired glucose controller (BIAP) based on a model of β-cell physiology is compared against a recently published PID controller with insulin feedback (PID-IF) using the UVa/Padova T1DM metabolic simulator.Both controllers were tuned using a 24-hour scenario containing a 40g(10am) carbohydrates meal and initial blood glucose of 160mg/dl. A single tuning parameter was adjusted to stabilize glucose around 100mg/dl, avoiding dropping below 80mg/dl. To compare controllers, a 24-hour scenario containing 3 meals (30g(6am), 40g(2pm), 20g(10pm)) was employed. In both controllers, a partial bolus corresponding to 50% of the required insulin to cover a meal was delivered at the time of ingestion. Standard metrics provided by the simulator were employed for comparison purposes.See table for results of BIAP and PID-IF in n=10 adult, n=10 adolescent and n=10 children in-silico subjects. Mean blood glucose with PID-IF was lower than with BIAP in the adult cohort, percentage of time below target with BIAP was lower in the children cohort, percentage of time within target with BIAP was higher in the adolescents cohort and risk index was lower with BIAP in the adult and adolescent groups.The tuning parameter in BIAP correlated very well with the insulin sensitivity factor of the test subjects (R2=0.9), while the correlation observed within PID-IF was lower (R2=0.6).The BIAP glucose controller performed comparably to the PID-IF controller in in-silico setting with superior metrics in an adolescent cohort. The BIAP controller can be easily tuned by using a simple correlation with the insulin sensitivity factor.
Trantidou T, Prodromakis T, Tsiligkiridis V, et al., 2013, Sensing H+ with conventional neural probes, Applied Physics Letters, Vol: 102, ISSN: 1077-3118
In this paper, we demonstrate a technique for transforming commercially available neural probes used for electrical recordings, into chemical sensing devices for detection of ionic concentrations in electrolytes, with particular emphasis to pH. This transformation requires a single post-processing step to incorporate a thin indium tin oxide membrane for sensing H+. Measured results indicate a chemical sensitivity of 28 mV/pH, and relatively low leakage currents (2–10 nA) and drifts (1–10 mV/h). The proposed sensing device demonstrates the possibility of a low-cost implementation that can be reusable and thus versatile, with potential applications in real-time extracellular but mainly intracellular chemical monitoring.
Berdan R, Prodromakis T, Salaoru I, et al., 2012, Memristive devices as parameter setting elements in programmable gain amplifiers, APPLIED PHYSICS LETTERS, Vol: 101, ISSN: 0003-6951
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- Citations: 24
Herrero P, Calm R, Vehi J, et al., 2012, Robust Fault Detection System For Insulin Pump Therapy using Continuous Glucose Monitoring, Journal of Diabetes Science and Technology, Vol: 6, Pages: 1131-1141
Background:The popularity of continuous subcutaneous insulin infusion (CSII), or insulin pump therapy, as a way to deliver insulin more physiologically and achieve better glycemic control in diabetes patients has increased. Despite the substantiated therapeutic advantages of using CSII, its use has also been associated with an increased risk of technical malfunctioning of the device, which leads to an increased risk of acute metabolic complications, such as diabetic ketoacidosis. Current insulin pumps already incorporate systems to detect some types of faults, such as obstructions in the infusion set, but are not able to detect other types of fault such as the disconnection or leakage of the infusion set. Methods:In this article, we propose utilizing a validated robust model-based fault detection technique, based on interval analysis, for detecting disconnections of the insulin infusion set. For this purpose, a previously validated metabolic model of glucose regulation in type 1 diabetes mellitus (T1DM) and a continuous glucose monitoring device were used. As a first step to assess the performance of the presented fault detection system, a Food and Drug Administration-accepted T1DM simulator was employed.Results:Of the 100 in silico tests (10 scenarios on 10 subjects), only two false negatives and one false positive occurred. All faults were detected before plasma glucose concentration reached 300 mg/dl, with a mean plasma glucose detection value of 163 mg/dl and a mean detection time of 200 min.Conclusions:Interval model-based fault detection has been proven (in silico) to be an effective tool for detecting disconnection faults in sensor-augmented CSII systems. Proper quantification of the uncertainty associated with the employed model has been observed to be crucial for the good performance of the proposed approach.
Berdan R, Prodromakis T, Toumazou C, 2012, High precision analogue memristor state tuning, ELECTRONICS LETTERS, Vol: 48, Pages: 1105-1106, ISSN: 0013-5194
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- Citations: 36
Guilvard A, Eftekhar A, Luan S, et al., 2012, A Fully-Programmable Neural Interface for Multi-Polar, Multi-Channel Stimulation Strategies, International Symposium on Circuits and Systems (ISCAS), ISSN: 0271-4302
This paper describes a novel integrated electrodeinterface for multi-polar stimulation of multi-electrode arrays. This interface allows for simultaneous stimulation using multiple electrodes configured as source or sink with different phase and amplitudes in order to perform field shaping inside the tissue. The system is designed in an high voltage 0.18 μm CMOS process with 8 channels. It features an output voltage swing of 16V and current up to 0.5mA for electrode impedences of up to 30kΩ which is suitable for cuff and cortical grid arrays. This electrode interface comprise a digital module which stores stimulation settings and operates the different electrode channels. Here we present the full system architecture and simulation results.
Al-Ahdal A, Toumazou C, 2012, High gain ISFET based νMOS chemical inverter, SENSORS AND ACTUATORS B-CHEMICAL, Vol: 171, Pages: 110-117
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- Citations: 9
Sanni A, Vilches A, Toumazou C, 2012, Inductive and Ultrasonic Multi-Tier Interface for Low-Power, Deeply Implantable Medical Devices, IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS, Vol: 6, Pages: 297-308, ISSN: 1932-4545
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- Citations: 47
Trantidou T, Prodromakis T, Toumazou C, 2012, Oxygen plasma induced hydrophilicity of Parylene-C thin films, Applied Surface Science, Vol: 261, Pages: 43-51, ISSN: 1873-5584
This paper investigates the surface modification of Parylene-C thin films under various oxygen plasma treatment conditions, such as power intensity (50:400 W) and exposure time (1:20 min). The extent of hydrophilicity was investigated through contact angle measurements, and correlations between treatment parameters, film thickness, restoration of hydrophobicity and etching rates were experimentally established. We also demonstrate the selective modification of Parylene-C films, facilitating distinct hydrophilic and hydrophobic areas with μm-resolution that can be exploited in self-alignment applications.
Lui KW, Murphy OH, Toumazou C, 2012, 32-mu W Wirelessly-Powered Sensor Platform With a 2-m Range, IEEE SENSORS JOURNAL, Vol: 12, ISSN: 1530-437X
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- Citations: 2
Prodromakis T, Toumazou C, Chua LO, 2012, Two centuries of memristors, Nature Materials, Vol: 11, Pages: 478-481
Mou Z, Triantis IF, Woods VM, et al., 2012, A Simulation Study of the Combined Thermoelectric Extracellular Stimulation of the Sciatic Nerve of the <i>Xenopus Laevis</i>: The Localized Transient Heat Block, IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING, Vol: 59, Pages: 1758-1769, ISSN: 0018-9294
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- Citations: 39
Lui KW, Murphy OH, Toumazou C, 2012, 32-μW Wirelessly-Powered Sensor Platform With a 2-m Range, IEEE SENSORS JOURNAL, Vol: 12, Pages: 1919-1924, ISSN: 1530-437X
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- Citations: 8
Liu Y, Al-Ahdal A, Georgiou P, et al., 2012, Minimal readout scheme for ISFET sensing arrays based on pulse width modulation, ELECTRONICS LETTERS, Vol: 48, Pages: 548-U28, ISSN: 0013-5194
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- Citations: 9
AlAhdal A, Toumazou C, 2012, ISFET-based chemical Schmitt trigger, ELECTRONICS LETTERS, Vol: 48, Pages: 549-550, ISSN: 0013-5194
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- Citations: 5
Al-Ahdal A, Toumazou C, 2012, ISFET-Based Chemical Switch, IEEE SENSORS JOURNAL, Vol: 12, Pages: 1140-1146, ISSN: 1530-437X
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- Citations: 7
Gelencsér A, Prodromakis T, Toumazou C, et al., 2012, Biomimetic model of the outer plexiform layer by incorporating memristive devices., Phys Rev E Stat Nonlin Soft Matter Phys, Vol: 85
In this paper we present a biorealistic model for the first part of the early vision of processing by incorporating memristive nanodevices. The architecture of the proposed network is based on the organization and functioning of the outer plexiform layer (OPL) in the vertebrate retina. We demonstrate that memristive devices are indeed a valuable building block for neuromorphic architectures, as their highly nonlinear and adaptive response could be exploited for establishing ultradense networks with dynamics similar to that of their biological counterparts. We particularly show that hexagonal memristive grids can be employed for faithfully emulating the smoothing effect occurring in the OPL to enhance the dynamic range of the system. In addition, we employ a memristor-based thresholding scheme for detecting the edges of grayscale images, while the proposed system is also evaluated for its adaptation and fault tolerance capacity against different light or noise conditions as well as its distinct device yields.
Murphy OH, McLeod CN, Navaratnarajah M, et al., 2012, A Pseudo-Normal-Mode Helical Antenna for Use With Deeply Implanted Wireless Sensors, IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, Vol: 60, Pages: 1135-1139, ISSN: 0018-926X
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- Citations: 27
Kalofonou M, Georgiou P, Ou C-P, et al., 2012, An ISFET based translinear sensor for DNA methylation detection, SENSORS AND ACTUATORS B-CHEMICAL, Vol: 161, Pages: 156-162
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- Citations: 28
Herrero P, Bondia J, Palerm CC, et al., 2012, A simple robust method for estimating the glucose rate of appearance from mixed meals., J Diabetes Sci Technol, Vol: 6, Pages: 153-162
BACKGROUND: Estimating the rate of glucose appearance (R(a)) after ingestion of a mixed meal may be highly valuable in diabetes management. The gold standard technique for estimating R(a) is the use of a multitracer oral glucose protocol. However, this technique is complex and is usually not convenient for large studies. Alternatively, a simpler approach based on the glucose-insulin minimal model is available. The main drawback of this last approach is that it also requires a gastrointestinal model, something that may lead to identifiability problems. METHODS: In this article, we present an alternative, easy-to-use method based on the glucose-insulin minimal model for estimation of R(a). This new technique avoids complex experimental protocols by only requiring data from a standard meal tolerance test. Unlike other model-based approaches, this new approach does not require a gastrointestinal model, which leads to a much simpler solution. Furthermore, this novel technique requires the identification of only one parameter of the minimal model because the rest of the model parameters are considered to have small variability. In order to account for such variability as well as to account for errors associated to measurements, interval analysis has been employed. RESULTS: The current technique has been validated using data from a United States Food and Drug Administration-accepted type 1 diabetes simulator [root mean square error (RMSE) = 0.77] and successfully tested with two clinical data sets from the literature (RMSE = 0.69). CONCLUSIONS: The presented technique for the estimation of R(a) showed excellent results when tested with simulated and actual clinical data. The simplicity of this new technique makes it suitable for large clinical research studies for the evaluation of the role of R(a) in patients with impairments in glucose metabolism. In addition, this technique is being used to build a model library of mixed meals that could be incorporated into diabetic su
Al-Ahdal A, Toumazou C, 2012, A Digital CHEMFET Front End, 16th IEEE Mediterranean Electrotechnical Conference (MELECON), Publisher: IEEE, Pages: 634-636, ISSN: 2158-8481
Spulber I, Georgiou P, Eftekhar A, et al., 2012, Frequency analysis of wireless accelerometer and EMG sensors data: Towards discrimination of normal and asymmetric walking pattern, Circuits and Systems (ISCAS), 2012 IEEE International Symposium on, Pages: 2645-2648
This preliminary study reports on the combined use of wireless accelerometers and wireless EMG sensors for monitoring walking patterns. The sensor data was analyzed in frequency domain through FFT, PSD and time-frequency spectrogram analysis. Accelerometer spectra was found to shift towards lower frequencies (<3 Hz) while EMG spectra of selected muscles shifted towards higher frequencies (>50 Hz) during asymmetric walking. Median frequency was used to quantify the spectral shifts. The combined wireless accelerometer/EMG system showed potential for discrimination between the normal and asymmetric walking.
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