This paper investigates the effects of a dielectric-constant mismatch between gate dielectric and silicon substrate on the capacitance-voltage curve of high-K MOS structures, numerically, via fully self-consistent solutions of Schrφdinger and Poisson equations. Results demonstrate that the capacitance-voltage curve of a high-K MOS structure compared to that of SiO ₂ MOS structure with the same equivalent oxide thickness shifts to lower gate voltage with increasing dielectric constant of the gate dielectric, thickness of gate dielectric, and acceptor density in silicon substrate. The results also demonstrate that a higher dielectric thickness, thicker gate dielectric, and higher acceptor density for a high-K MOS structure lead to a larger increase in capacitance compared to SiO ₂ MOS structure with the same ­equivalent oxide thickness.

[ABSTRACT]  [FULL TEXT]  [PDF]

Cooperative relaying is a promising approach to enlarge coverage area and enhance system capacity. Capacity of such a system depends on the SNR of the received signal. Therefore, allocation of available power between source and relay, to achieve maximum SNR, is an important issue. A power allocation scheme depends not only on channel state information (CSI) but also on the degree of knowledge of this CSI. This paper investigates different power allocation strategies in presence of full CSI, without CSI, and statistical CSI through simulation studies. Knowledge of full CSI can be utilized to obtain optimal performance at the cost of system complexity. Use of statistical feedback reduces complexity and its performance is found to be close to optimal one. Its performance is close to optimum one for the placement of relay node near destination or with decrease in fading severity. However, in the absence of CSI, placement of relay at middle is the best solution, for similar channel conditions.

[ABSTRACT]  [FULL TEXT]  [PDF] [CITATIONS]

This paper presents a bandwidth increasing technique using a modified ground plane with diagonal edges for the design of compact antennas. The proposed low-cost, compact-size circular patch antenna on 3 cm x 5.1 cm printed circuit board (FR-4) is designed and validated through simulations and experiments. Results show that with ­diagonal cuts at corners of the ground plane, the enhanced bandwidth can be tunable depending on the removed area. Return losses of minus 17 and minus 30 dBs for the first and second resonant frequencies, respectively, can be achieved when the depth of the diagonal cut is at optimum value of five mm, providing an 18.13% wider bandwidth (2.95-12.615 GHz) than the Federal Communication Commission (FCC) standard.

[ABSTRACT]  [FULL TEXT]  [PDF] [CITATIONS]

Charge Coupled Devices (CCDs) are used in imaging as they have advantages over conventional bulky tube type TV cameras. The complementary metal oxide semiconductor (CMOS) based image sensors, passive pixel sensors (PPS), and active pixel sensor (APS) have advantages in implementation. This makes the APS competitive with CCDs. However, APS is not popular because of the poor fill factor and lack of resolution. With the development of image sensor technology, digital pixel sensor (DPS) has overcome all problems associated with CCDs and CMOS-APS image sensor. In DPS, comparator and memory are implemented on chip for each pixel. This results in benefits in terms of power, pixel size, fill factor and resolutions. This paper analyses earlier DPS pixel with an analog comparator and inverter-based comparator. The limitations reported in the analysis of analog comparator are overcome using cascaded CMOS inverter-based comparator. The cascaded CMOS inverter is built with proper adjustment of Width (W) to Length (L) ratio. This adjustment sets the threshold voltage 'V _th ' that remains fixed for the pixel (in our case V _th is equal to 2.2V). This cascaded inverter based comparator is called as threshold inverter quantizer (TIQ) and is further analyzed with biasing for high gain. Four-pixel and 16-pixel array design is done using TIQ based pixel. Extensive simulation of the TIQ based pixel array is done and results are reported for current and power dissipation.

[ABSTRACT]  [FULL TEXT]  [PDF] [CITATIONS]

It is challenging to maintain normoglycemic range of glucose concentration in type I diabetic patients. In this study H` control is applied for insulin delivery to prevent the hyperglycemic levels in a type I diabetic patient. From a ­control theory point of view, the blood glucose regulation problem is reformulated as a tracking one. A glucose ­tolerance curve (GTC) validated from several patients is used as reference model. Intra- and inter-patient ­variability poses a ­challenging task to control blood glucose concentration in diabetic patients. We develop a data based ­robust ­controller to control blood glucose concentration in type I diabetic (TIDM) patients in the presence of meal ­disturbances under patient-model mismatch. Simulation studies are performed on the diabetic patient model under feedback control. It is seen that the proposed control strategy is able to control blood glucose concentration well within the acceptable limits and also compensate for slow parametric drifts.

[ABSTRACT]  [FULL TEXT]  [PDF] [CITATIONS]

In this paper, we explore a new voice quality management model under ambience environment suitable for voice over internet protocol (VoIP) calls in wireless WLAN 802.11 Linux environment. The system is based on a setup that assimilates environment noise level using noise detector and adaptive audio manager used to tune the audio level and thereby quality is ensured. Further, existing models such as E-model, PESQ model and adaptive model address QoS in a VoIP networking perspective but do not address voice quality management in real time environment to ­improve voice quality. We propose to use background noise and its associated source information in an adaptive ­environment to boost user perception, audio level, thereby ensuring quality. This issue is important because in real time, consumers might be interested in mobiles that address ambience effect to determine human audible effect based on environment conditions. The experimental results of the proposed method outperform the existing method in terms of QoS factor metric; we get extensive results with more number of calls.

[ABSTRACT]  [FULL TEXT]  [PDF]

In this paper, we apply the sorting network theory to construct an analog rank order filter. We present a voltage mode CMOS two-input sorting element and arrange these to form a rank order filter. The resulting circuit is simple and is a high-speed, high-precision design. Although the transistor count is moderately higher than other designs, the proposed circuit simultaneously outputs signals of all ranks rather than of just one specified rank. We also develop a slightly modified design which calculates the rank of a given signal. We present reports of simulations to verify the performance of the device.

[ABSTRACT]  [FULL TEXT]  [PDF] [CITATIONS]

[FULL TEXT]  [PDF]

A novel wavelength assignment method is proposed for a bidirectional WDM ring network and the minimum number of wavelengths required to support all-to-all broadcast is determined. The new method can assign each wavelength directly and simultaneously to a group of non-overlapping connections on an N-node ring without the aid of any table or matrix. The presented wavelength assignment method is much faster than other direct methods with explicit ­formulas previously reported for WDM ring network.

[ABSTRACT]  [FULL TEXT]  [PDF] [CITATIONS]