An 8-Bit, 100-MSPS Fully Dynamic SAR ADC for Ultra-High Speed Image Sensor
In this paper, a dynamic and power efficient 8-bit and 100-MSPS Successive Approximation Register (SAR) Analog-to-Digital Converter (ADC) is presented. The circuit uses a non-differential capacitive Digital-to-Analog (DAC) architecture segmented by 2. The prototype is produced in a commercial 65-nm 1P7M CMOS technology with 1.2-V supply voltage. The size of the core ADC is 208.6 x 103.6 µm2. The post-layout noise simulation results feature a SNR of 46.9 dB at Nyquist frequency, which means an effective number of bit (ENOB) of 7.5-b. The total power consumption of this SAR ADC is only 1.55 mW at 100-MSPS. It achieves then a figure of merit of 85.6 fJ/step.
Extended Constraint Mask Based One-Bit Transform for Low-Complexity Fast Motion Estimation
In this paper, an improved motion estimation (ME) approach based on weighted constrained one-bit transform is proposed for block-based ME employed in video encoders. Binary ME approaches utilize low bit-depth representation of the original image frames with a Boolean exclusive-OR based hardware efficient matching criterion to decrease computational burden of the ME stage. Weighted constrained one-bit transform (WC‑1BT) based approach improves the performance of conventional C-1BT based ME employing 2-bit depth constraint mask instead of a 1-bit depth mask. In this work, the range of constraint mask is further extended to increase ME performance of WC-1BT approach. Experiments reveal that the proposed method provides better ME accuracy compared existing similar ME methods in the literature.
FPGA Implementation of Adaptive Clock Recovery for TDMoIP Systems
Circuit switched networks widely used until the end of the 20th century have been transformed into packages switched networks. Time Division Multiplexing over Internet Protocol (TDMoIP) is a system that enables Time Division Multiplexing (TDM) traffic to be carried over packet switched networks (PSN). In TDMoIP systems, devices that send TDM data to the PSN and receive it from the network must operate with the same clock frequency. In this study, it was aimed to implement clock synchronization process in Field Programmable Gate Array (FPGA) chips using time information attached to the packages received from PSN. The designed hardware is verified using the datasets obtained for the different carrier types and comparing the results with the software model. Field tests are also performed by using the real time TDMoIP system.
Conditions for Fault Recovery of Interconnected Asynchronous Sequential Machines with State Feedback
In this paper, fault recovery for parallel interconnected
asynchronous sequential machines is studied. An adversarial input
can infiltrate into one of two submachines comprising parallel
composition of the considered asynchronous sequential machine,
causing an unauthorized state transition. The control objective is to
elucidate the condition for the existence of a corrective controller
that makes the closed-loop system immune against any occurrence
of adversarial inputs. In particular, an efficient existence condition
is presented that does not need the complete modeling of the
interconnected asynchronous sequential machine.
Improvement of GVPI Insulation System Characteristics by Curing Process Modification
The curing process of insulation system for electrical machines plays a determinative role for its durability and reliability. Polar structure of insulating resin molecules and used filler of insulation system can be taken as an occasion to leverage it to enhance overall characteristics of insulation system, mechanically and electrically. The curing process regime for insulating system plays an important role for its mechanical and electrical characteristics by arranging the polymerization of chain structure for resin. In this research, the effect of electrical field application on in-curing insulating system for Global Vacuum Pressurized Impregnation (GVPI) system for traction motor was considered by performing the dissipation factor, polarization and de-polarization current (PDC) and voltage endurance (aging) measurements on sample test objects. Outcome results depicted obvious improvement in mechanical strength of the insulation system as well as higher electrical characteristics with routing and long-time (aging) electrical tests. Coming together, polarization of insulation system during curing process would enhance the machine life time.
A Low Profile Dual Polarized Slot Coupled Patch Antenna
A low profile, dual polarized, slot coupled patch antenna is designed and developed in this paper. The antenna has a measured bandwidth of 17.2% for return loss > 15 dB and pair ports isolation >23 dB. The gain of the antenna is over 10 dBi and the half power beam widths (HPBW) of the antenna are 80±3o in the horizontal plane and 39±2o in the vertical plane. The cross polarization discrimination (XPD) is less than 20 dB in HPBW. Within the operating band, the performances of good impedance match, high ports isolation, low cross polarization, and stable radiation patterns are achieved.
Batteryless DCM Boost Converter for Kinetic Energy Harvesting Applications
In this paper, a bidirectional boost converter operated
in Discontinuous Conduction Mode (DCM) is presented as a suitable
power conditioning circuit for tuning of kinetic energy harvesters
without the need of a battery. A nonlinear control scheme, composed
by two linear controllers, is used to control the average value of
the input current, enabling the synthesization of complex loads. The
converter, along with the control system, is validated through SPICE
simulations using the LTspice tool. The converter model and the
controller transfer functions are derived. From the simulation results,
it was found that the input current distortion increases with the
introduced phase shift and that, such distortion, is almost entirely
present at the zero-crossing point of the input voltage.
A 3Y/3Y Pole-Changing Winding of High-Power Asynchronous Motors
Requirement for pole-changing motors emerged at the very early times of asynchronous motor design. Different solutions have been elaborated and some of them are generally used. An alternative is the so called 3 Y/3 Y pole-changing winding. This paper deals with high power application of this solution. A complete and comprehensive study is introduced, including features and design guidelines. The method presented in this paper is especially suitable for pole numbers being close to each other. The study also reveals that the method is more advantageous then the existing solutions for high power motors with 1:3 pole ratio. Using this motor, a new and complete drive supply system has been proposed as most appropriate arrangement of high power main naval propulsion drive. Further, the method makes possible to extend the pole ratio to 1:6, 1:9, 1:12, etc. At the end, the proposal is further extended to the here so far missing 1:4, 1:5, 1:7 etc. pole ratios. A complete proposal for the theoretically infinite range has been given in this way.
Development and Range Testing of a LoRaWAN System in an Urban Environment
This paper describes the construction and operation of an experimental LoRaWAN network surrounding the University of Southampton in the United Kingdom. Following successful installation, an experimental node design is built and characterised, with particular emphasis on radio range. Several configurations are investigated, including different data rates, and varying heights of node. It is concluded that although range can be great (over 8 km in this case), environmental topology is critical. However, shorter range implementations, up to about 2 km in an urban environment, are relatively insensitive although care is still needed. The example node and the relatively simple base station reported demonstrate that LoraWan can be a very low cost and practical solution to Internet of Things type applications for distributed monitoring systems with sensors spread over distances of several km.
The Security Trade-Offs in Resource Constrained Nodes for IoT Application
The concept of the Internet of Things (IoT) has
received much attention over the last five years. It is predicted
that the IoT will influence every aspect of our lifestyles in the
near future. Wireless Sensor Networks are one of the key enablers
of the operation of IoTs, allowing data to be collected from the
surrounding environment. However, due to limited resources, nature
of deployment and unattended operation, a WSN is vulnerable to
various types of attack. Security is paramount for reliable and safe
communication between IoT embedded devices, but it does, however,
come at a cost to resources. Nodes are usually equipped with small
batteries, which makes energy conservation crucial to IoT devices.
Nevertheless, security cost in terms of energy consumption has
not been studied sufficiently. Previous research has used a security
specification of 802.15.4 for IoT applications, but the energy cost
of each security level and the impact on quality of services (QoS)
parameters remain unknown. This research focuses on the cost of
security at the IoT media access control (MAC) layer. It begins
by studying the energy consumption of IEEE 802.15.4 security
levels, which is followed by an evaluation for the impact of security
on data latency and throughput, and then presents the impact of
transmission power on security overhead, and finally shows the effects
of security on memory footprint. The results show that security
overhead in terms of energy consumption with a payload of 24 bytes
fluctuates between 31.5% at minimum level over non-secure packets
and 60.4% at the top security level of 802.15.4 security specification.
Also, it shows that security cost has less impact at longer packet
lengths, and more with smaller packet size. In addition, the results
depicts a significant impact on data latency and throughput. Overall,
maximum authentication length decreases throughput by almost 53%,
and encryption and authentication together by almost 62%.
Bluetooth Piconet System for Child Care Applications
This study mainly concerns a safety device designed for child care. When children are out of sight or the caregivers cannot always pay attention to the situation, through the functions of this device, caregivers can immediately be informed to make sure that the children do not get lost or hurt, and thus, ensure their safety. Starting from this concept, a device is produced based on the relatively low-cost Bluetooth piconet system and a three-axis gyroscope sensor. This device can transmit data to a mobile phone app through Bluetooth, in order that the user can learn the situation at any time. By simply clipping the device in a pocket or on the waist, after switching on/starting the device, it will send data to the phone to detect the child’s fall and distance. Once the child is beyond the angle or distance set by the app, it will issue a warning to inform the phone owner.
The Excess Loop Delay Calibration in a Bandpass Continuous-Time Delta Sigma Modulators Based on Q-Enhanced LC Filter
The Q-enhanced LC filters are the most used
architecture in the Bandpass (BP) Continuous-Time (CT)
Delta-Sigma (ΣΔ) modulators, due to their: high frequencies
operation, high linearity than the active filters and a high quality
factor obtained by Q-enhanced technique. This technique consists
of the use of a negative resistance that compensate the ohmic
losses in the on-chip inductor. However, this technique introduces a
zero in the filter transfer function which will affect the modulator
performances in term of Dynamic Range (DR), stability and in-band
noise (Signal-to-Noise Ratio (SNR)). In this paper, we study the
effect of this zero and we demonstrate that a calibration of the
excess loop delay (ELD) is required to ensure the best performances
of the modulator. System level simulations are done for a 2ndorder
BP CT (ΣΔ) modulator at a center frequency of 300MHz. Simulation
results indicate that the optimal ELD should be reduced by 13% to
achieve the maximum SNR and DR compared to the ideal LC-based
Performance Evaluation of Thermosiphon Based Solar Water Heater in India
This paper aims to study performance of a thermosiphon solar water heating system with the help of the proposed analytical model. This proposed model predicts the temperature and mass flow rate in a thermosiphon solar water heating system depending on radiation intensity and ambient temperature. The performance of the thermosiphon solar water heating system is evaluated in the Indian context. For this, eight cities in India are selected considering radiation intensity and geographical positions. Predicted performance at various cities reveals the potential for thermosiphon solar water in India.
An Intelligent Baby Care System Based on IoT and Deep Learning Techniques
Due to the heavy burden and pressure of caring for infants, an integrated automatic baby watching system based on IoT smart sensing and deep learning machine vision techniques is proposed in this paper. By monitoring infant body conditions such as heartbeat, breathing, body temperature, sleeping posture, as well as the surrounding conditions such as dangerous/sharp objects, light, noise, humidity and temperature, the proposed system can analyze and predict the obvious/potential dangerous conditions according to observed data and then adopt suitable actions in real time to protect the infant from harm. Thus, reducing the burden of the caregiver and improving safety efficiency of the caring work. The experimental results show that the proposed system works successfully for the infant care work and thus can be implemented in various life fields practically.
A Multiple Beam LTE Base Station Antenna with Simultaneous Vertical and Horizontal Sectorization
A low wind-load light-weight broad-band multi-beam base station antenna has been developed. It can generate any required number of beams with the required beamwidths. It can have horizontal and vertical sectorization at the same time. Vertical sectorization doubles the overall number of beams. It will be very valuable in LTE-A and 5G. It can be used to serve vertically split inner and outer cells, which improves system performance. The intersection between the beams of the proposed multi-beam antenna can be controlled by optimizing the design parameters of the antenna. The gain at the points of intersection between the beams, the null filling and the overlap between the beams can all be modified. The proposed multi-beam base station antenna can cover an unlimited number of wireless applications, regardless of their frequency bands. It can simultaneously cover all, current and future, wireless technology generations such as 2G, 3G, 4G (LTE), --- etc. For example, in LTE, it covers the bands 450-470 MHz, 690-960 MHz, 1.4-2.7 GHz and 3.3-3.8 GHz. It has at least 2 ports for each band in each beam for ±45° polarizations. It can include up to 72 ports or even more, which could facilitate any further needed capacity expansions.
12x12 MIMO Terminal Antennas Covering the Whole LTE and WiFi Spectrum
A broadband resonant terminal antenna has been developed. It can be used in different MIMO arrangements such as 2x2, 4x4, 8x8, or even 12x12 MIMO configurations. The antenna covers the whole LTE and WiFi bands besides the existing 2G/3G bands (700-5800 MHz), without using any matching/tuning circuits. Matching circuits significantly reduce the efficiency of any antenna and reduce the battery life. They also reduce the bandwidth because they are frequency dependent. The antenna can be implemented in smartphone handsets, tablets, laptops, notebooks or any other terminal. It is also suitable for different IoT and vehicle applications. The antenna is manufactured from a flexible material and can be bent or folded and shaped in any form to fit any available space in any terminal. It is self-contained and does not need to use the ground plane, the chassis or any other component of the terminal. Hence, it can be mounted on any terminal at different positions and configurations. Its performance does not get affected by the terminal, regardless of its type, shape or size. Moreover, its performance does not get affected by the human body of the terminal’s users. Because of all these unique features of the antenna, multiples of them can be simultaneously used for MIMO diversity coverage in any terminal device with a high isolation and a low correlation factor between them.
Automatic Classification of Periodic Heart Sounds Using Convolutional Neural Network
This paper presents an automatic normal and abnormal heart sound classification model developed based on deep learning algorithm. MITHSDB heart sounds datasets obtained from the 2016 PhysioNet/Computing in Cardiology Challenge database were used in this research with the assumption that the electrocardiograms (ECG) were recorded simultaneously with the heart sounds (phonocardiogram, PCG). The PCG time series are segmented per heart beat, and each sub-segment is converted to form a square intensity matrix, and classified using convolutional neural network (CNN) models. This approach removes the need to provide classification features for the supervised machine learning algorithm. Instead, the features are determined automatically through training, from the time series provided. The result proves that the prediction model is able to provide reasonable and comparable classification accuracy despite simple implementation. This approach can be used for real-time classification of heart sounds in Internet of Medical Things (IoMT), e.g. remote monitoring applications of PCG signal.
Comparative Analysis of SVPWM and the Standard PWM Technique for Three Level Diode Clamped Inverter fed Induction Motor
The multi-level inverters present an important novelty in the field of energy control with high voltage and power. The major advantage of all multi-level inverters is the improvement and spectral quality of its generated output signals. In recent years, various pulse width modulation techniques have been developed. From these technics we have: Sinusoidal Pulse Width Modulation (SPWM) and Space Vector Pulse Width Modulation (SVPWM). This work presents a detailed analysis of the comparative advantage of space vector pulse width modulation (SVPWM) and the standard SPWM technique for Three Level Diode Clamped Inverter fed Induction Motor. The comparison is based on the evaluation of harmonic distortion THD.
PIN-Diode Based Slotted Reconfigurable Multiband Antenna Array for Vehicular Communication
In this paper, a patch antenna array design is proposed for vehicular communication. The antenna consists of 2-element patch array. The antenna array is operating at multiple frequency bands. The multiband operation is achieved by use of slots at proper locations at the patch. The array is made reconfigurable by use of two PIN-diodes. The antenna is simulated and measured in four states of diodes i.e. ON-ON, ON-OFF, OFF-ON, and OFF-OFF. In ON-ON state of diodes, the resonant frequencies are 4.62-4.96, 6.50-6.75, 6.90-7.01, 7.34-8.22, 8.89-9.09 GHz. In ON-OFF state of diodes, the measured resonant frequencies are 4.63-4.93, 6.50-6.70 and 7.81-7.91 GHz. In OFF-ON states of diodes the resonant frequencies are 1.24-1.46, 3.40-3.75, 5.07-5.25 and 6.90-7.20 GHz and in the OFF-OFF state of diodes 4.49-4.75 and 5.61-5.98 GHz. The maximum bandwidth of the proposed antenna is 16.29%. The peak gain of the antenna is 3.4 dB at 5.9 GHz, which makes it suitable for vehicular communication.