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The purpose of this work in designing a wideband ring voltage-controlled oscillator (VCO) based on programmable current topology. It occupies a very tiny area yet achieving a good phase noise performance, which is suitable to be implemented in cost-effective and wideband frequency synthesizers.

The tuning range and gain are improved by dividing the VCO tuning curve into multiple curves controlled by programmable current sources without introducing additional parasitic capacitance.

Fabricated in 130-nm standard complementary metal oxide semiconductor technology and occupying an area of 0.079 mm², the VCO is tunable from 2.05 to 4.19 GHz, with a tuning percentage of 68.5 per cent. The VCO measures a phase noise performance of −96.7 dBc/Hz at an offset of 1 MHz from a 4.19 GHz carrier while consuming an average current of 6.5 mA, achieving figure of merit (FoM) and FoM_T of −158.9 and −175.6 dBc/Hz, respectively.

The proposed design uses programmable current topology without introducing parasitic capacitance, hence achieving wideband operation. It also occupies a tiny area and achieves a good phase noise performance.

To describe the development of a three dimensional programmable transceiver system of modular design for use as a development tool for a variety of wireless sensor node applications.

As a stepping‐stone towards the development of wireless nodes, sensor networks programme was put in place to develop a 25 mm cube module, which was modular in construction, programmable and miniaturised in form factor. This was to facilitate the development of wireless sensor networks for a variety of different applications. The nodes are used as a platform for sensing and actuating through various parameters, for use in scalable, reconfigurable distributed autonomous sensing networks in a number of research projects currently underway in the Tyndall Institute, as well as other institutes and in a variety of research programs in the area of wireless sensor networks.

The modular construction enables the heterogeneous implementation of a variety of technologies required in the arena of wireless sensor networks: Intelligence, numerical processing, memory, sensors, power supply and conditioning, all in a similar form factor. This enables rapid deployment of different sensor network nodes in an application specific fashion.

Characterisation of the transceiver module is ongoing, particularly in the field of the wireless communication platform utilized, and its capabilities.

A rapid prototyping and development cycle of application specific wireless sensor networks has been enabled by the development of this modular system.

This paper provides information about the development work and some potential application areas made available by the implementation of a miniaturised modular wireless sensor node for use in a variety of application scenarios.

This paper aims to investigate the perception threshold (PT) of electrotactile stimulation under non-steady contact condition (NSCC) which is rarely considered in previous reports mainly because of the difficulty with experimental control. Three factors of NSCC are involved, including the current alternating frequency, the tapping interval of stimulation and the stimulating area of skin. The study is aimed at providing the basic PT data for design and application of wearable and portable electrotactile device.

The up-down method was selected to assess PT, and 72 experimental scenarios were constructed. During the study, we developed an experimental platform with the function of data record and programmable current stimulation. With psychophysical experiment, more than 10,000 data were collected. Furthermore, statics analysis and ANOVA test were opted for exploring the main factor influencing PT.

NSCC has different PTs on each body location, and PT has a positive correlation with frequency. In general, PT in NSCC is significantly lower than that in SCC. In some cases, it can be lower by more than 60 per cent. In addition, women have a lower PT than men across all age groups, and the younger is generally more sensitive than the older in electro-sensation.

Limited factors of NSCC were considered in this study. Contact time and break interval should be investigated in the future work.

The paper includes implications for the development of smart electrotactile device.

This paper fulfills a challenge in assessing the PT under NSCC.

The paper aims to develop a wireless addressing interface circuitry for solid propellant microthruster array applications.

The solid propellant microthruster is a relatively new class of micropropulsion system for microspacecraft. To produce a controlled vectored thrust, a microthruster array is needed. Realization of the addressing ability and wireless communication is the key to the development of the microthruster array. Therefore, a prototype wireless addressing circuitry was developed to realize the addressing of the microthruster array by a multiplexing system. The addressing circuitry also enables measurement of the igniter temperature variation with time by measuring the igniter resistance change and automatic control by RS232 and RF wireless communications. Operating principles, design, fabrication, and testing of the circuitry are addressed.

A prototype integrated wireless addressing circuitry was designed and fabricated to realize the addressing of individual microthrusters in the microthruster array, to measure the igniter temperature variation with time, and to achieve automatic control using RS232 and RF wireless communications. Using the programmable voltage source in the circuitry, the igniter temperature could be accurately controlled in 256 steps using an 8 bit word. The 10 bit analog‐to‐digital converter feedback loop circuitry enabled real‐time monitoring of each igniter in the microthruster array and allowing each igniter to be functionally controlled.

In this paper, a wireless addressing interface circuitry is developed for the first time for solid propellant microthruster array applications.

The purpose of this paper is to describe the application of soft systems methodology (SSM) to address the problematic situation of low opt-in rates for Precision Health-Care (PHC).

The design logic is that when trust is enhanced and compliance is better assured, participants such as patients and their doctors would be more likely to share their medical data and diagnosis for the purpose of precision modeling.

The authors present the findings of an empirical study that confronts the design challenge of increasing participant opt-in to a PHC repository of Electronic Medical Records and genetic sequencing. Guided by SSM, the authors formulate design rules for the establishment of a trust-less platform for PHC which incorporates key principles of transparency, traceability and immutability.

The SSM approach has been criticized for its lack of “rigour” and “replicability”. This is a fallacy in understanding its purpose – theory exploration rather than theory confirmation. Moreover, it is unlikely that quantitative modeling yields any clearer an understanding of complex, socio-technical systems.

The application of Blockchain, a platform for distributed ledgers, and associated technologies present a feasible approach for resolving the problematic situation of low opt-in rates.

A consequence of low participation is the weak recall and precision of descriptive, predictive and prescriptive analytic models. Factors such as cyber-crime, data violation and the potential for misuse of genetic and medical records have led to a lack of trust from key stakeholders – accessors, participants, miners and regulators – to varying degrees.

The application of Blockchain as a trust-enabling platform in the domain of an emerging eco-system such as precision health is novel and pioneering.

THE great expansion in the use of complex electronic equipment over the past few years has imposed an ever increasing problem of testing and maintaining such equipments on both the source manufacturer and the user. Automatic testing can to a large degree solve this problem by increasing the speed and reliability of the testing method and by reducing the manpower involved.

The purpose of this paper is to discuss the effect of electric reverse stress currents on the performance of photovoltaic solar modules.

The effect of a reverse introduced current as a function of time is studied on the I‐V and C‐V characteristics and parameters which were extracted and analyzed using numerical analysis based on a reliable double exponential model.

The effect of an introduced reverse current for different periods simulated the effect of accumulated extreme reverse currents which may arise in solar cells and modules due to different reasons, causing dramatic changes in the shunt resistance as well as other characteristics, mainly when the time of the current application exceeded a certain limit.

The paper contributes to the research on the damaging effects of reverse currents on the normal operation of the solar cells and modules.

Spring Test Probe for Microcircuit Testing Coda Systems have announced the availability of a new range of spring test probes originating from their principal, Ostby and Barton, which have been specifically designed for the testing of thick and thin film microcircuits.

The purpose of this study is to investigate the effect of electrical and thermal stresses on the void formation of the Sn3.0Ag0.5Cu (SAC305) lead-free ball grid array (BGA) solder joints and to propose a modified mean-time-to-failure (MTTF) equation when joints are subjected to coupling stress.

The samples of the BGA package were subjected to a migration test at different currents and temperatures. Voltage variation was recorded for analysis. Scanning electron microscope and electron back-scattered diffraction were applied to achieve the micromorphological observations. Additionally, the experimental and simulation results were combined to fit the modified model parameters.

Voids appeared at the corner of the cathode. The resistance of the daisy chain increased. Two stages of resistance variation were confirmed. The crystal lattice orientation rotated and became consistent and ordered. Electrical and thermal stresses had an impact on the void formation. As the current density and temperature increased, the void increased. The lifetime of the solder joint decreased as the electrical and thermal stresses increased. A modified MTTF model was proposed and its parameters were confirmed by theoretical derivation and test data fitting.

This study focuses on the effects of coupling stress on the void formation of the SAC305 BGA solder joint. The microstructure and macroscopic performance were studied to identify the effects of different stresses with the use of a variety of analytical methods. The modified MTTF model was constructed for application to SAC305 BGA solder joints. It was found suitable for larger current densities and larger influences of Joule heating and for the welding ball structure with current crowding.