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The post-matching (PM) topology is an effective approach to broaden the bandwidth of Doherty power amplifiers (DPA). However, its efficiency has been limited because previous works only considered the fundamental frequency termination, and not the harmonics. In this paper, a modified phase compensation network is used in the PM Doherty topology to realize a third harmonic open as viewed by both carrier...
In this paper, the use of semantic web parsing technique in extracting learning design elements from existing course materials published on the web is described. The rationale of this work is to assist the authoring process of IMS Learning Design (IMS-LD) and thus boosting the adoption of the standard as a publication format of course materials on the Internet. By adopting IMS-LD, learners can be...
A new algorithm is proposed for robust principal component analysis with predefined sparsity patterns. The algorithm is then applied to separate the singing voice from the instrumental accompaniment using vocal activity information. To evaluate its performance, we construct a new publicly available iKala dataset that features longer durations and higher quality than the existing MIR-1K dataset for...
A low-complexity residual carrier frequency offsets (CFOs) estimation scheme of a multiuser uplink orthogonal frequency division multiplexing (OFDM) system is presented as an improvement to the traditional time-multiplexed method. This method employs an orthogonal code, such as the Frank-Zadoff code, in the training sequence. Each antenna transmits this code sequence according to a prearranged schedule...
Personal identification from the iris images acquired under less-constrained imaging environment is highly challenging problem but with several important applications in surveillance, image forensics, search for missing children and wandering elderly. In this paper, we develop and formulate a new approach for the iris recognition using hypercomplex (quaternionic or octonionic) and sparse representation...
Automated human identification at-a-distance, using completely automated iris segmentation, is highly challenging and has wide range of civilian and forensics applications. Iris images acquired at-a-distance using visible and infrared imaging are often noisy and suffer from divergent spectral changes largely resulting from scattering, albedo and spectral absorbance selectivity. Therefore further research...
Planar microstrip branch line couplers are simple but have narrow bandwidth and are unable to reject out-of-band signals adequately. This paper proposes a new feeding network for branch line couplers, using this feeding network the bandwidth of the coupler has a five-fold increase in bandwidth and with bandpass characteristics. The flat response is obtained by impedance matching from the feeding network,...
Every design engineer has an experience of facing common problems of short lead times, clear specification, sufficient design criteria, material costing, environmental regulations, and product reliability constraints. However, for maintaining sustainable growth of a company, a new product should be time-in-market that keeping business growth strategy. Under such environment, it is clear that more...
For the first time a reconfigurable top loaded monopole antenna is proposed for use in multiband wireless applications. It was designed and verified for operation across the frequency range from 1.8 GHz to 4.6 GHz using a simple switching approach. To further increase the tuning range of the antenna, higher order space-filling curve could be used.
This work describes a simple active quasi-circulator that gives wideband operation, and differs from previous structures which were limited to a narrow frequency range. Experimental results shows good return loss and isolation within the expected operating frequency range, making it practical to implement.
This paper introduces the development of a mobile human airbag system that is designed for fall protection for the elderly. A Micro Inertial Measurement Unit (mulMU) that is 66 mm x 20 mm x 20 mm in size is built. This unit consists of three dimensional MEMS accelerometers, gyroscopes, and a Bluetooth module. It records human motion information, and, with a Support Vector Machine (SVM) training process,...
A sickle-shape patch dipolar antenna is proposed for UWB use. When optimizing the proposed antenna by genetic algorithm, it not only has a wide impedance bandwidth, but also has a constant radiation pattern across the operating frequency band. Thus, distortion can be reduced throughout the entire UWB frequency range, making it a good choice for UWB systems.
This paper describes the development of a human airbag system which is designed to reduce the impact force from slippage falling-down. A micro inertial measurement unit (muIMU) which is based on MEMS accelerometers and gyro sensors is developed as the motion sensing part of the system. A weightless recognition algorithm is used for real-time falling determination. With the algorithm, the microcontroller...
In this paper, an active broadband integrated antenna is presented. The antenna can operate from 900 MHz to 2.3 GHz, with 87.5% bandwidth and over 12 dBi gain. This antenna can directly connect with the differential output of the IC module to provide amplification, radiation and signal combination. Since, there are no more broadband hybrids, the size and the complexity of the unit can be reduced....
Traditional radio frequency bi-directional amplifiers rely on switches with their associated increase in cost, size and loss to achieve time division duplexing. A switchless bi-directional amplifier is proposed whereby the power amplifier (PA) and low noise amplifier (LNA) are connected directly in an anti-parallel configuration. Experimental results show that there is no gain degradation when compared...
This paper describes the development of a human airbag system which is designed to reduce the impact force from falls. A micro inertial measurement unit (muIMU), based on MEMS accelerometers and gyro sensors is developed as the motion sensing part of the system. A recognition algorithm is used for real-time fall determination. With the algorithm, a microcontroller integrated with the muIMU can discriminate...
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