Generation of Generalized Impedance Converter Circuits Using NAM Expansion

The generation of the voltage generalized impedance converter (VGIC) circuits using a nodal admittance matrix (NAM) expansion is given in detail. Thirty-two equivalent circuits using current conveyors (CCII) or inverting current conveyors (ICCII) or a combination of both are generated. The reported circuits are suitable for realizing inductors or frequency dependent negative resistors (FDNR) using grounded passive elements. Similarly the generation of the current generalized impedance converter (CGIC) circuits published recently is reexamined and this resulted in 16 more new CGIC circuits using an alternative NAM expansion. Modification of two of the generated circuits to realize a floating inductor or floating FDNR is also given together with Spice simulation results.     

A Behavioral Model of MEMS Convective Accelerometers for the Evaluation of Design and Calibration Strategies at System Level

This paper presents a behavioral model that can be used to improve the manufacturability of systems based on MEMS convective sensors. This model permits to handle faults related to process scattering, taking into account not only the electrical and lateral geometrical parameters but also the influence of the cavity depth. Moreover correlations between conductive and convective phenomena are included. The model is validated with respect to FEM simulations and a very good agreement is obtained between the behavioral model and FEM results. The proposed model can then be used in system-level simulations, for instance to evaluate the impact of process scattering on the performances of the sensing part and/or to investigate different design and calibration strategies with respect to the system robustness.     

Conceptual framework for the security of mobile health applications on Android platform

Mobile Health (mHealth) applications are readily accessible to the average user of mobile devices, and despite the potential of mHealth applications to improve the availability, affordability and effectiveness of delivering healthcare services, they handle sensitive medical data, and as such, have also the potential to carry substantial risks to the security and privacy of their users. Developers of applications are usually unknown, and users are unaware of how their data are being managed and used. This is combined with the emergence of new threats due to the deficiency in mobile applications development or the design ambiguities of the current mobile operating systems. A number of mobile operating systems are available in the market, but the Android platform has gained the topmost popularity. However, Android security model is short of completely ensuring the privacy and security of users’ data, including the data of mHealth applications. Despite the security mechanisms provided by Android such as permissions and sandboxing, mHealth applications are still plagued by serious privacy and security issues. These security issues need to be addressed in order to improve the acceptance of mHealth applications among users and the efficacy of mHealth applications in the healthcare systems. Thus, this paper presents a conceptual framework to improve the security of medical data associated with Android mHealth applications, as well as to protect the privacy of their users. Based on the literature review that suggested the need for the intended security framework, three-distinct and successive phases are presented, each of which is described in a separate section. First, discussed the design process of the first phase to develop a security framework for mHealth apps to ensure the security and privacy of sensitive medical data. The second phase is discussed who to achieve the implementation of a prototypic proof-of-concept version of the framework. Finally, the third phase ending discussed the evaluation process in terms of effectiveness and efficiency for the proposed framework.     

Effects of Plasticizers,Antioxidants and Burning Rate Modifiers on Aging Performance of the HTPB/HMDI Composite Solid Propellant

The effects of plasticizers,antioxidants and burning rate modifiers on the aging performance of the composite solid propellant based on hydroxyl-terminated polybutadiene(HTPB)/hexamethylene diisocyanate(HMDI)were explored by apply-ing an accelerated aging program for 90 day at 70 ℃. The HTPB propellant matrix with the diisooctyl sebacate(DOS)as plasti-cizers and diisooctyl azelate(DOZ), antioxidants as N,N ′-Diphenyl-p-phenylenediamine(AO) and 2,2′-methylenebis(4-methyl-6-tert-butylphenol)(cyanox 2246)and burning rate modifiers as barium ferrite(BF),copper chromites(CC)and fer-ric oxide(FO)were varied. Results show that sample(S1)which based on DOS decreases the stress value and increases the strain value which considered to be an excellent start for aging program. Sample(S3)containing AO presents the higher resis-tance to oxidation showing the better performance that reflects on increasing the shelf life of the composite solid propellant mo-tor. Sample(S5)which based on BF enhances the ballistic performance among over the other tested two samples. The accelerat-ed aging program allowed us to estimate the motor in-service lifetime.     

Configurable FFT Processor Using Dynamically Reconfigurable Resource Arrays

This paper presents results of using a Coarse Grain Reconfigurable Architecture called DRRA (Dynamically Reconfigurable Resource Array) for FFT implementations varying in order and degree of parallelism using radix-2 decimation in time (DIT). The DRRA fabric is extended with memory architecture to be able to deal with data-sets much larger than what can be accommodated in the register files of DRRA. The proposed implementation scheme is generic in terms of the number of FFT point, the size of memory and the size of register file in DRRA. Two implementations (DRRA-1 and DRRA-2) have been synthesized in 65 nm technology and energy/delay numbers measured with post-layout annotated gate level simulations. The results are compared to other Coarse Grain Reconfigurable Architectures (CGRAs), and dedicated FFT processors for 1024 and 2048 point FFT. For 1024 point FFT, in terms of FFT operations per unit energy, DRRA-1 and DRRA-2 outperforms all CGRA by at least 2× and is worse than ASIC by 3.45×. However, in terms of energy-delay product DRRA-2 outperforms CGRAs by at least 1.66× and dedicated FFT processors by at least 10.9×. For 2048-point FFT, DRRA-1 and DRRA-2 are 10× better for energy efficiency and 94.84 better for energy-delay product. However, radix-2 implementation is worse by 9.64× and 255× in terms of energy efficiency and energy-delay product when compared against a radix-2⁴ implementation.

     

The case for SIMO random access in multi-antenna multi-hop wireless networks

In this paper, we demonstrate that multiple concurrent asynchronous and uncoordinated Single-Input Multiple-Output (SIMO) transmissions can successfully take place even though the respective receivers do not explicitly null out interfering signals. Hence, we propose simple modifications to the widely deployed IEEE 802.11 Medium Access Control (MAC) to enable multiple non-spatially-isolated SIMO sender-receiver pairs to share the medium. Namely, we propose to increase the physical carrier sense threshold, disable virtual carrier sensing, and enable message-in-message packet detection. We use experiments to show that while increasing the peak transmission rate, spatial multiplexing schemes such as those employed by the IEEE 802.11n are highly non-robust to asynchronous and uncoordinated interferers. In contrast, we show that the proposed multi-flow SIMO MAC scheme alleviates the severe unfairness resulting from uncoordinated transmissions in 802.11 multi-hop networks. We analytically compute the optimal carrier sense threshold based on different network performance objectives for a given node density and number of receive antennas.     

Potential interference and rain attenuation at 21.4–22 GHz downlink broadcasting satellite signals

World Radio Conference WRC-1992 has allocated the frequency band 21.4–22.0?GHz to regions 1 and 3 to be utilised to carry direct broadcasting satellite (DBS) services. This high-frequency band is more susceptible to rain attenuation, leading to degradation of the signal quality. Moreover, this frequency band is assigned to two different services, i.e. satellite broadcasting and fixed mobile services at the same regions; hence, the impact of intersystem interference in a depredated signal is a critical issue in the DBS receiver. In this study, the effects of rain attenuation on the DBS downlink signals as well as the impact of the potential interference on the reception quality will be estimated. An interference scenario will be introduced to investigate the system performance in both propagation mechanisms of clear-sky and rain conditions.     

Impact of Offloading on the Efficiency of Wireless Access Networks

International Journal of Wireless Information Networks - Wireless access networks need to deliver a satisfactory level of Quality of Service (QoS) to their subscribers. The service quality can be...     

WCDMA Multiclass Downlink Capacity and Interference Statistics of Cigar-Shaped Microcells in Highways

In this paper, the multiclass downlink capacity and the interference statistics of the sectors of a cigar-shaped microcells using wideband code-division multiple-access with soft handover mode are analyzed. The two-slope propagation model with log-normal shadowing is used in the analysis where a model of 8 cigar-shaped microcells is utilized. The performance of the downlink is studied for different [sector range R, standard deviation of the shadowing ( $\sigma _{1}$ and $\sigma _{2})$ and propagation exponents ( $\text{ s}_{1}$ and $\text{ s}_{2})$ ]. It is found that increasing the sector range from 500 to 1,000 m will increase the sector downlink capacity. Also, it is found that increasing the value of the propagation parameters ( $\sigma _{1}$ and $\sigma _{2})$ will reduce the downlink sector capacity. It is noticed that, the effect of changing the propagation exponent $\text{ s}_{1}$ is null while increasing the propagation exponent $\text{ s}_{2}$ will increase the downlink capacity.     

INSPAD: a system for automatic bond pad inspection

A method of detecting probe mark defects in semiconductor bond pads is presented that uses digitized images of color Polaroid photographs from an optical microscope. INSPAD inspects the bond pads in a magnified IC circuit image taken after the electrical testing stage. These are: probe marks must not extend beyond pad boundaries such that they damage glassivation; scratches on the bond pads must not exceed 50% of the bond pad width; and the probe marks must not exceed 25% of the bond pad area. Three types of commonly used bond pad geometries have been addressed. Morphological filtering is performed on the bond pad, to isolate and identify the major probe mark regions. Inspection of each pad takes approximately 2 to 3 s on an Apollo DN-4000 workstation which makes it suitable for real-time applications