| 1. |
- Alickovic, Emina, et al.
(författare)
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Ensemble SVM Method for Automatic Sleep Stage Classification
- 2018
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0018-9456 .- 1557-9662. ; 67:6, s. 1258-1265
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Tidskriftsartikel (refereegranskat)abstract
- Sleep scoring is used as a diagnostic technique in the diagnosis and treatment of sleep disorders. Automated sleep scoring is crucial, since the large volume of data should be analyzed visually by the sleep specialists which is burdensome, time-consuming tedious, subjective, and error prone. Therefore, automated sleep stage classification is a crucial step in sleep research and sleep disorder diagnosis. In this paper, a robust system, consisting of three modules, is proposed for automated classification of sleep stages from the single-channel electroencephalogram (EEG). In the first module, signals taken from Pz-Oz electrode were denoised using multiscale principal component analysis. In the second module, the most informative features are extracted using discrete wavelet transform (DWT), and then, statistical values of DWT subbands are calculated. In the third module, extracted features were fed into an ensemble classifier, which can be called as rotational support vector machine (RotSVM). The proposed classifier combines advantages of the principal component analysis and SVM to improve classification performances of the traditional SVM. The sensitivity and accuracy values across all subjects were 84.46% and 91.1%, respectively, for the five-stage sleep classification with Cohens kappa coefficient of 0.88. Obtained classification performance results indicate that, it is possible to have an efficient sleep monitoring system with a single-channel EEG, and can be used effectively in medical and home-care applications.
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| 2. |
- Alizadeh, Mahmoud, et al.
(författare)
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Measurement and Analysis of Frequency-Domain Volterra Kernels of Nonlinear Dynamic 3 x 3 MIMO Systems
- 2017
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0018-9456 .- 1557-9662. ; 66:7, s. 1893-1905
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Tidskriftsartikel (refereegranskat)abstract
- Multiple-input multiple-output (MIMO) frequencydomain Volterra kernels of nonlinear order 3 are experimentally determined in bandwidth-limited frequency regions. How the effect of higher nonlinear orders can be reduced and how this affects the estimated errors are discussed. The magnitude and the phase of the kernels are Kramers-Kronig consistent. The self-kernels and cross-kernels have different symmetries, and the kernels are therefore determined and analyzed in different regions in the 3-D frequency space. By analyzing the properties along certain paths in the 3-D frequency space, the block structures for the respective kernels are determined. These block structures contain the significant blocks of the general block structures for the third-order kernels. The device under test is an MIMO transmitter for radio frequency signals.
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| 3. |
- Alizadeh, Mahmoud, et al.
(författare)
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Measurement and analysis of frequency-domainVolterra kernels of nonlinear dynamic 3x3 MIMO systems
- 2016
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : IEEE Press. - 0018-9456 .- 1557-9662.
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Tidskriftsartikel (refereegranskat)abstract
- Multiple-input multiple-output (MIMO) frequency-domain Volterra kernels of nonlinear order 3 are experimentally determined in bandwidth-limited frequency regions. How the effect of higher nonlinear orders can be reduced and how this affects the estimated errors are discussed. The magnitude and phase of the kernels areKramers-Kronig consistent. The self- and cross-kernels have different symmetries and the kernels are therefore determined and analyzed in different regions in the 3D frequency space. By analyzing the properties along certain paths in the 3D frequency space, the block structures for the respective kernels are determined. These block structures contain the significant blocks of the general block structures for third-order kernels. The device under test is a MIMO transmitter for radio frequency signals.
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| 4. |
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| 5. |
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| 6. |
- Amin, Shoaib, et al.
(författare)
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Characterization of concurrent dual-band Power Amplifiers using a dual two-tone excitation signal
- 2015
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : IEEE Press. - 0018-9456 .- 1557-9662. ; :99
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Tidskriftsartikel (refereegranskat)abstract
- A method to characterize the memory effects in a nonlinear concurrent dual-band transmitter is presented. It is an extension of the conventional two tone test for power amplifiers to concurrent dual band transmitters. The output signal of a concurrent dual-band transmitter is affected not only by intermodulation products but also by cross-modulation products. In one frequency band, the transmitter is excited by a two tone signal which frequency separation is swept. In the second band the transmitter is concurrently excited by an other two tone signal with slightly wider frequency separation. The frequency difference of the two signals is fixed during the frequency sweep. The two tone test is made at different power levels. The upper and lower third-order inter- and cross-modulation products are measured. The asymmetry between the upper and lower third-order inter- and cross-modulation products are measures of the transmitter's memory effects. The measurement results show that the memory effects are more dominant in the third-order intermodulation products than in the cross modulation products. An error analysis and system calibration was performed and measurement results for two different devices are presented.
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| 7. |
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| 8. |
- Andersen, Olav, et al.
(författare)
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Extending the Bandwidth and Dynamic Range of Old RF Instruments to Meet State-of-the-Art Performance, Using a Synthetic Instrument Approach
- 2009
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456 .- 1557-9662. ; 58:2, s. 248-254
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Tidskriftsartikel (refereegranskat)abstract
- A decrease in life cycle cost is a key issue for testing mobile communication systems. The rapid development and edge technology requires high-performance instruments and state-of-the-art measurement technology. New investments are expensive, but even older generation instruments are capable of extending their bandwidth and dynamic range to meet even the latest Third-Generation Partnership Project (3GPP) cellular measurement requirements by the addition of external hardware using a synthetic instrument approach. The novelty of this paper is the high performance on the most crucial parameters, i.e., the dynamic range and bandwidth achieved by only replacing some parts of the legacy instrument. Moreover, the demonstrated direct IF synthesis has a high degree of novelty at wide modulation bandwidths. It is desired to use virtual/synthetic instruments and make the signal processing in the software independent of the hardware, i.e., software-defined measurements (SDMs). In this paper, a state-of-the-art experimental setup for signal generation and signal analysis is demonstrated. A direct IF synthesis is used to generate a wideband code-division multiple-access (WCDMA) carrier with more than 72-dB adjacent carrier leakage ratio (ACLR) up to 12 parallel carriers with more than 68-dBc ACLR over a total bandwidth of 100 MHz. The signal analysis capabilities (e.g., ACLR performance) for a WCDMA carrier is better than -70 dBc and for a continuous wave better than -85 dBc over a bandwidth of 42.5 MHz. The critical RF downconverter in the setup is carefully designed not to degrade the dynamic range performance.
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| 9. |
- Andersson, Tomas, et al.
(författare)
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IEEE standard 1057, Cramer-Rao bound and the parsimony principle
- 2006
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9456 .- 1557-9662. ; 55:1, s. 44-53
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Tidskriftsartikel (refereegranskat)abstract
- This paper deals with some fundamental properties of the sine-wave-fit algorithm included in IEEE Standards 1057 and 1241. Asymptotic Cramer-Rao bounds (CRBs) for three and four model parameters are derived under the Gaussian assumption. Further, the sine-wave-fitting properties of the algorithm are analyzed by the parsimony principle. A decision criterion whether to use the three- or four-parameter model is derived. It is shown that a three-parameter sine-wave fit produces a better fit than the four-parameter fit if the frequency is known to be within an interval related to the number of samples and the signal-to-noise ratio. By a numerical analysis, the theoretical results are shown to be also valid for the uniform noise model of quantization.
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| 10. |
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| 11. |
- Aranda, Jesus Javier Lechuga, et al.
(författare)
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An Apparatus For The Performance Estimation Of Pressure Fluctuation Energy Harvesters
- 2018
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : IEEE. - 0018-9456 .- 1557-9662. ; 67:11, s. 2705-2713
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Tidskriftsartikel (refereegranskat)abstract
- Hydraulic pressure fluctuation energy harvesters are promising alternatives to power up wireless sensor nodes in hydraulic systems. The characterization of these harvesters under dynamic and band-limited pressure signals is imperative for the research and development of novel concepts. To generate and control these signals in a hydraulic medium, a versatile apparatus capable of reproducing pressure signals is proposed. In this paper, a comprehensive discussion of the design considerations for this apparatus and its performance is given. The suggested setup enables the investigation of devices tailored for the harvesting of energy in conventional hydraulic systems. To mimic these systems, static pressures can be tuned up to 300 bar, and the pressure amplitudes with a maximum of 28 Bar at 40 Hz and 0.5 bar at 1000 Hz can be generated. In addition, pressure signals found in commercial hydraulic systems can be reproduced with good accuracy. This apparatus proves to be an accessible, robust, and versatile experimental setup to create environments for the complete performance estimation of pressure fluctuation energy harvesters.
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| 12. |
- Ascorti, Leonardo, et al.
(författare)
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A Wireless Cloud Network Platform for Industrial Process Automation : Critical Data Publishing and Distributed Sensing
- 2017
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456 .- 1557-9662. ; 66:4, s. 592-603
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Tidskriftsartikel (refereegranskat)abstract
- Wireless technologies combined with advanced computing are changing industrial communications. Industrial wireless networks can improve the monitoring and the control of the entire system by jointly exploiting massively interacting communication and distributed computing paradigms. In this paper, we develop a wireless cloud platform for supporting critical data publishing and distributed sensing of the surrounding environment. The cloud system is designed as a self-contained network that interacts with devices exploiting the time synchronized channel hopping protocol (TSCH), supported by WirelessHART (IEC 62591). The cloud platform augments industry-standard networking functions as it handles the delivery (or publishing) of latency and throughput-critical data by implementing a cooperative-multihop forwarding scheme. In addition, it supports distributed sensing functions through consensus-based algorithms. Experimental activities are presented to show the feasibility of the approach in two real industrial plant sites representative of typical indoor and outdoor environments. Validation of cooperative forwarding schemes shows substantial improvements compared with standard industrial solutions. Distributed sensing functions are developed to enable the autonomous identification of recurring cochannel interference patterns.
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| 13. |
- Barac, Filip, et al.
(författare)
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Scrutinizing Bit- and Symbol-Errors of IEEE 802.15.4 Communication in Industrial Environments
- 2014
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456 .- 1557-9662. ; 63:7, s. 1783-1794
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Tidskriftsartikel (refereegranskat)abstract
- The knowledge of error nature in wireless channels is an essential constituent of efficient communication protocol design. To this end, this paper is the first comprehensive bit- and symbol-level analysis of IEEE 802.15.4 transmission errors in industrial environments. The intention with this paper is to extract the error properties relevant for future improvements of wireless communication reliability and coexistence of radio systems in these harsh conditions. An extensive set of bit-error traces was collected in a variety of scenarios and industrial environments, showing that error behavior is highly dependent on the cause of packet corruption. It is shown that errors inflicted by multipath fading and attenuation exhibit different properties than those imposed by IEEE 802.11 interference. The statistical behavior of these two patterns is concurrently investigated in terms of differences in bit-error distribution, error burst length, channel memory length, and the scale of packet corruption. With these conclusions at hand, abiding to the computational constraints of embedded sensors and the statistical properties of bit-errors, a Reed-Solomon $(15,k)$ block code is chosen to investigate the implications of bit-error nature on practical aspects of channel coding and interleaving. This paper is concluded by a number of findings of high practical relevance, concerning the optimal type, depth, and meaningfulness of interleaving.
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| 14. |
- Barbé, Kurt, et al.
(författare)
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A Simple Nonparametric Preprocessing Technique to Correct for Nonstationary Effects in Measured Data
- 2012
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456 .- 1557-9662. ; 61:8, s. 2085-2094
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Tidskriftsartikel (refereegranskat)abstract
- The general approach for modeling systems assumes that the measured signals are (weakly) stationary, i.e., the power spectrum is time invariant. However, the stationarity assumption is violated when: 1) transient effects due to experimental conditions are dominant; 2) data are missing due to, for instance, sensor failure; or 3) the amplitude of the excitation signals smoothly varies over time due to, for instance, actuator problems. Although different methods exist to deal with each of these nonstationary effects specifically, no unified approach is available. In this paper, a new and general technique is presented to handle nonstationary effects, based on processing overlapping subrecords of the measured data. The proposed method is a simple preprocessing step where the user does not need to specify which nonstationary effect is present, nor the time interval where the nonstationary effect appears. The merits of the proposed approach are demonstrated on an operational wireless system suffering from interrupted link effects.
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| 15. |
- Bastos, M. C., et al.
(författare)
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A high-voltage test bed for the evaluation of high-voltage dividers for pulsed applications
- 2011
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456 .- 1557-9662. ; 60:7, s. 2462-2468
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Tidskriftsartikel (refereegranskat)abstract
- The design, evaluation, and commissioning of a high-voltage reference test bed for pulsed applications to be used in the precision testing of high-voltage dividers is described. The test bed is composed of a pulsed power supply, a reference divider based on compressed-gas capacitor technology, and an acquisition system that makes use of the fast measurement capabilities of the HP3458 digital voltmeter. The results of the evaluation of the reference system are presented. © 2006 IEEE.
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| 16. |
- Baumann, N., et al.
(författare)
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Piepser 2.0 : A Self-Sustaining Smartwatch to Maximize the Paragliders Flytime
- 2020
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers Inc.. - 0018-9456 .- 1557-9662. ; 69:4, s. 1445-1454
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Tidskriftsartikel (refereegranskat)abstract
- The main motivation of paraglider pilots is to stay in the air for as long as possible. Therefore, paraglider pilots are always searching for thermal upwind that allow them to gain altitude. These thermal lifts are difficult to detect. Therefore, sensors and devices that indicate the vertical speed (so-called variometers) are widely used among paraglider pilots. This article presents the design and the implementation of an ultralow-power, self-sustaining, high-precision, wrist-worn variometer with a minimal form factor but infinite lifetime, which can visually and acoustically indicate the vertical velocity. This article demonstrates the benefits of combining multisource energy harvesting (EH) for wearable devices with low power design, exploiting a novel near-threshold ARM Cortex-M4F microcontroller, the Ambiq Apollo2, for the onboard processing. The experimental results show a power consumption of only 17.12~\mu \text{W} in sleep mode and 1937.21~\mu \text{W} in the worst case scenario when processing the data and outputting an audio feedback. Measurements confirmed that combining both thermal and solar EH makes the designed electronics self-sustaining. Without EH, the system will be operational for up to 372 h in always-on mode (worst case scenario) supplied by a 200-mAh lithium-ion battery. © 1963-2012 IEEE.
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| 17. |
- Beltramelli, Luca, et al.
(författare)
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Energy efficiency of slotted LoRaWANcommunication with out-of-band synchronization
- 2021
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456 .- 1557-9662.
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Tidskriftsartikel (refereegranskat)abstract
- Although the idea of using wireless links for covering large areas is not new, the advent of Low Power Wide area networks (LPWANs) has recently started changing the game. Simple, robust, narrowband modulation schemes permit the implementation of low-cost radio devices offering high receiver sensitivity, thus improving the overall link budget. The several technologies belonging to the LPWAN family, including the well-known LoRaWAN solution, provide a cost-effective answer to many Internet-of-things (IoT) applications, requiring wireless communication capable of supporting large networks of many devices (e.g., smart metering). Generally, the adopted medium access control (MAC) strategy is based on pure ALOHA, which, among other things, allows to minimize the traffic overhead under constrained duty cycle limitations of the unlicensed bands. Unfortunately, ALOHA suffers from poor scalability, rapidly collapsing in dense networks. This work investigates the design of an improved LoRaWAN MAC scheme based on slotted ALOHA. In particular, the required time dissemination is provided by out-of-band communications leveraging on Radio Data System(FM-RDS) broadcasting, which natively covers wide areas both indoor and outdoor. An experimental setup based on low-cost hardware is used to characterize the obtainable synchronization performance and derive a timing error model. Consequently, improvements in success probability and energy efficiency have been validated by means of simulations in very large networks with up to 10000 nodes. It is shown that the advantage of the proposed scheme over conventional LoRaWAN communication is up to 100% when short update time and large payload are required. Similar results are obtained regarding the energy efficiency improvement, that is close to 100% for relatively short transmission intervals and long message duration; however, due to the additional overhead for listening the time dissemination messages, efficiency gain can be negative for very short duration of message fastly repeating.
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| 18. |
- Bergman, Anders, et al.
(författare)
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A Constant Voltage Source Based on a Mercury Battery
- 1993
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9456 .- 1557-9662. ; 42:2, s. 365-367
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Tidskriftsartikel (refereegranskat)abstract
- A constant voltage source based on a stable mercury battery has been developed at SP (Swedish National Testing and Research Institute). By using as active current compensation technique, the inherent high stability of a mercury battery can be retained up to a load current of several milliamperes.
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| 19. |
- Bergman, Sixten, et al.
(författare)
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New reference measurement system for calibration of VLF high voltage
- 2011
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456 .- 1557-9662. ; 60:7, s. 2422-2426
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Tidskriftsartikel (refereegranskat)abstract
- A reference measuring system for 200 kV from very low frequencies (0.1 Hz, VLF) up to 50 Hz based on traditional high-voltage components, such as compressed gas capacitors, has been developed and verified. The verification of the measuring system has been performed by two experimental methods, one directly measuring the scale factor and one using measurements over the frequency and voltage range of the components of the measuring system. The frequency dependence of the measuring system proved to be one of the dominating uncertainties and was extensively researched. Proper correction for known errors and estimation of uncertainty contributions proved that traceable measurement of VLF voltage can be made with an uncertainty of less than 0.038% up to a voltage of 200 kV. This measurement service has been notified to be included in SP entries for Bureau International des Poids et Mesures key comparison database and can serve an important need for the cable industry. © 2006 IEEE.
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| 20. |
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| 21. |
- Bergsten, Tobias, et al.
(författare)
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An Active Filter for Delta-Sigma-Modulated Josephson Waveforms
- 2015
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456 .- 1557-9662. ; 64:6, s. 1559-1563
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Tidskriftsartikel (refereegranskat)abstract
- We present the design and electrical characteristics of an active low-pass filter. It will be used in a reference waveform source based on a programmable Josephson voltage standard with multilevel delta-sigma modulation to generate accurate and spectrally pure arbitrary waveforms. The filter has a fifth-order Butterworth characteristic with high input impedance, low distortion, high stopband attenuation, and stable passband performance, including dc.
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| 22. |
- Bergsten, Tobias, et al.
(författare)
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Realization of Absolute Phase and AC Resistance of Current Shunts by Ratio Measurements
- 2019
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456 .- 1557-9662. ; 68:6, s. 2041-2046
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a simplified method for realizing absolute phase and ac resistance for current shunts using only impedance ratio measurements. The method is based on three geometrically identical current shunts with different resistances, but with the same inductance, capacitance, and ac-dc resistance change of resistance at ac compared to dc). We demonstrate how the inductance, capacitance, and ac resistance can be calculated from the complex impedance ratio measurements, therefore realizing absolute current shunt impedance. The method gives competitive uncertainties of around 200 μΩ/Ω for amplitude and 400 μrad for phase at 1 MHz in the 1-Ω range.
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| 23. |
- Björsell, Niclas, et al.
(författare)
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Histogram Tests for Wideband Applications
- 2008
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456 .- 1557-9662. ; 57:1, s. 70-75
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Tidskriftsartikel (refereegranskat)abstract
- Characterization and testing of analog-to-digital converters (ADCs) are important for many reasons. A histogram test is a common method to characterize the linearity features of an ADC. Two commonly used stimulus signals are sine waves and Gaussian noise. This paper presents a metrological comparison between Gaussian and sine-wave histogram tests for wide-band applications, that is, we evaluate the performance of the characterization of the ADC and the usability of postcorrection. A postcorrection procedure involves the characterization of the ADC nonlinearity and then the use of this information by processing the ADC output samples to remove the distortion. The results show that the Gaussian histogram test gives reasonable accuracy in measuring nonlinearities. However, it does not result in a suitable model for postcorrection in wideband applications. A single-tone sine-wave histogram will be a better basis for postcorrection. The best result can be obtained if the lookup table is trained with several single-tone sine waves in the frequency band.
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| 24. |
- Björsell, Niklas, et al.
(författare)
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Measuring Volterra Kernels of Analog To Digital Converters Using a Stepped Three-Tone Scan
- 2008
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456 .- 1557-9662. ; 57:4, s. 666-671
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Tidskriftsartikel (refereegranskat)abstract
- The Volterra theory can be used to mathematically model nonlinear dynamic components such as analog-to-digital converters (ADCs). This paper describes how frequency-domain Volterra kernels of an ADC are determined from measurements. The elements of the Volterra theory are given, and practical issues are considered, such as methods for signal conditioning and finding the appropriate test signals scenario and suitable sampling frequency. The results show that, for the used pipeline ADC, the frequency dependence is significantly stronger for second-order difference products than for sum products and the linear frequency dependence was not as pronounced as that of the second-order Volterra kernel. It is suggested that the Volterra kernels have the symmetry properties of a specific box model, namely, the parallel Hammerstein system.
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| 25. |
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