Dose control circuit for digital electrostatic electron-beam array lithography

This paper demonstrates a technique for controlling the electron emission of an array of field emitting vertically aligned carbon nanofibers (VACNFs). An array of carbon nanofibers (CNF) is to be used as the source of electron beams for lithography purposes. This tool is intended to replace the mask in the conventional photolithography process by controlling their charge emission using the “Dose Control Circuitry” (DCC). The large variation in the charge emitted between CNFs grown in identical conditions forced the controller design to be based on fixed dose rather than on fixed time. Compact digital control logic has been designed for controlling the operation of DCC. This system has been implemented in a 0.5 μm CMOS process. Chandra Sekhar A. Durisety received his B.E. (Hons.) Instrumentation from Birla Institute of Technology and Sciences, Pilani, India in 1997 and his M.S in Electrical Engineering from University of Tennessee, Knoxville in 2002. Since 2003, he has been working towards his Ph.D degree also in Electrical Engineering at Integrated Circuits and Systems Lab (ICASL), University of Tennessee, Knoxville. He joined Wipro Infotech Ltd, Global R & D, Bangalore, India in 1997, where he designed FPGA based IPs for network routers. Since 1999, he was involved in the PCI bridge implementation at CMOS chips Inc, Santa Clara, CA, and the test bench development for Sony’s MP3 player, while at Toshiba America Electronic Components Inc., San Jose, CA. His research interests include multi-stage amplifiers, data converters, circuits in SOI and Floating Gate Devices. Rajagopal Vijayaraghavan received the B.E degree in electronics and communication engineering from Madras University in 1998 and the M.S degree in electrical engineering from the University of Texas, Dallas in 2001.He is currently working towards the Ph.D degree in electrical engineering at the University of Tennessee. His research interest is in the area of CMOS Analog and RF IC design. His current research focuses on LNAs and VCOs using SOI based MESFET devices. Lakshmipriya Seshan was born in Trivandrum, India on April 30, 1979. She received her B.tech in Electronincs & Communication Engg from Kerala University, India in June 2000 and M.S in Electrical Engg from University of Tennessee in 2004. In 2004, she joined Intel Corporation as an Analog Engineer, where she is engaged in the design of low power, high speed analog circuits for various I/O interface topologies. Syed K. Islam received his B.Sc. in Electrical and Electronic Engineering from Bangladesh University of Engineering and Technology (BUET) and M.S. and Ph.D. in Electrical and Systems Engineering from the University of Connecticut. He is presently an Associate Professor in the Department of Electrical and Computer Engineering at the University of Tennessee, Knoxville. Dr. Islam is leading the research efforts of the Analog VLSI and Devices Laboratory at the University of Tennessee. His research interests are design, modeling and fabrication of microelectronic/optoelectronic devices, molecular scale electronics and nanotechnology, biomicroelectronics and monolithic sensors. Dr. Islam has numerous publications in technical journals and conference proceedings in the areas of semiconductors devices and circuits. Benjamin J. Blalock received his B.S. degree in electrical engineering from The University of Tennessee, Knoxville, in 1991 and the M.S. and Ph.D. degrees, also in electrical engineering, from the Georgia Institute of Technology, Atlanta, in 1993 and 1996 respectively. He is currently an Assistant Professor in the Department of Electrical and Computer Engineering at The University of Tennessee where he directs the Integrated Circuits and Systems Laboratory (ICASL). His research focus there includes analog IC design for extreme environments (both wide temperature and radiation immune), multi-gate transistors and circuits on SOI, body-driven circuit techniques for ultra low-voltage analog, mixed-signal/mixed-voltage circuit design for systems-on-a-chip, and bio-microelectronics. Dr. Blalock has co-authored over 60 published refereed papers. He has also worked as an analog IC design consultant for Cypress Semiconductor Corp. and Concorde Microsystems Inc.     

Multiattribute‐based routing for lifetime maximization in opportunistic mobile social networks

With the advancement in wireless technology and portable devices, smart phones have become one of the belongings of human being. People share their data online, but it has limitations due to transmission range and mobility. Yet opportunistic mobile social network enables users to share data online even if there is no connected path between source and destination. The widespread use of mobile phones equipped with WiFi, Bluetooth, and several other components and contact opportunities among humans bridge the gap between internet available and nonavailable area. In this paper, we have proposed a new routing approach which utilizes both spatial and temporal attributes of user such as probability to meet a particular location and remaining intercontact time between two nodes to select better relay nodes. Generally, users visit different locations such as sports stadium and mall, with varying probability. Users with similar interest form group, and each user has different intercontact time with other users according to their point of interest and visiting pattern. By utilizing multiattributes, different forwarding strategies have been devised for both inter and intragroup routing. The proposed work “point of interest (PoI)‐based routing” is implemented in Opportunistic Network Environment simulator, and the performance is analysed in terms of delivery rate, latency, overhead, goodput, and energy consumed. The simulation results show that PoI diminishes 23% of overhead and yields 24% improvement in goodput over the state‐of‐the‐art protocol. Thus, the simulation results reveal that our proposed work provides the balance between routing performance and resource consumption.     

Data broadcasting strategies for cognitive radio based AMI networks

Wireless Networks - Communication systems play an important role in smart grid (SG). Advanced Metering Infrastructure (AMI) is hybrid architecture in smart grid comprising of smart meters and...     

Energy‐efficient data transmission technique for wireless sensor networks based on DSC and virtual MIMO

In a wireless sensor network (WSN), the data transmission technique based on the cooperative multiple‐input multiple‐output (CMIMO) scheme reduces the energy consumption of sensor nodes quite effectively by utilizing the space‐time block coding scheme. However, in networks with high node density, the scheme is ineffective due to the high degree of correlated data. Therefore, to enhance the energy efficiency in high node density WSNs, we implemented the distributed source coding (DSC) with the virtual multiple‐input multiple‐output (MIMO) data transmission technique in the WSNs. The DSC‐MIMO first compresses redundant source data using the DSC and then sends it to a virtual MIMO link. The results reveal that, in the DSC‐MIMO scheme, energy consumption is lower than that in the CMIMO technique; it is also lower in the DSC single‐input single‐output (SISO) scheme, compared to that in the SISO technique at various code rates, compression rates, and training overhead factors. The results also indicate that the energy consumption per bit is directly proportional to the velocity and training overhead factor in all the energy saving schemes.     

Analysis of Multi-Server Scheduling Paradigm for Service Guarantees during Network Mobility

Multi-server scheduling of traffic flows over heterogeneous wireless channels affix fresh concerns of inter-packet delay variations and associated problems of out-of-sequence reception, buffer management complexity, packet drops and re-ordering overhead. In this paper, we have presented an exclusive multi-server scheduling algorithm that is specifically tuned for mobile routers equipped with multiple wireless interfaces and has attained multiple care-of-address registrations with its home agent (HA). The proposed adaptive, Self-clocked, Multi-server (ASM) scheduling algorithm is based on predetermined transmission deadlines for each arrived packet at the mobile router. The mobile flows receive desired service levels in accordance with their negotiated service rates and are only constraint by the cumulative capacity of all active links. The major challenge lies in the handling of asymmetric channels to stitch into a unified virtual channel of higher capacity with reliable service guarantees during mobility. The sorted list of transmission schedules is used to assign physical channels in increasing order of their availability. This approach specifically encapsulates the physical layer disconnections during the handovers and ensures continuous service to ongoing flows. The proposed scheduling scheme is supplemented by an analytical model and simulations to verify its efficacy. The simulation results demonstrate higher degree of reliability and scalability of service provisioning to flows during mobility.     

A universal low-noise analog receiver baseband in 65-nm CMOS

In this paper, a novel universal receiver baseband approach is introduced. The chain includes a post-mixer noise shaping blocker pre-filter, a programmable-gain post mixer amplifier (PMA) with blocker suppression, a differential ramp-based novel linear-in-dB variable gain amplifier and a Sallen–Key output buffer. The 1.2-V chain is implemented in a 65-nm CMOS process, occupying a die area of 0.45 mm². The total power consumption of the baseband chain is 11.5 mW. The device can be tuned across a bandwidth of 700-KHz to 5.2-MHz with 20 kHz resolution and is tested for two distinct mobile-TV applications; integrated services digital broadcasting-terrestrial ISDB-T (3-segment f _c = 700 kHz) and digital video broadcasting-terrestrial/handheld (DVB-T/H f _c = 3.8 MHz). The measured IIP3 of the whole chain for the adjacent blocker channel is 24.2 and 24 dBm for the ISDB-T and DVB-T/H modes, respectively. The measured input-referred noise density is 10.5 nV/sqrtHz in DVB-T/H mode and 14.5 nV/sqrtHz in ISDB-T mode.     

Body controlled threshold voltage shifting variable gain current mirror

A programmable high-speed source-series-terminated driver with signal boost capability is presented. The driver uses only one main input data tap and is divided into main units and auxiliary units. A passive high pass filter is utilized to detect data transitions and control the inputs of the auxiliary units to enable a programmable amplitude boost for the output signal. The corner frequency of the high pass filter is adjusted depending on the data rate. Further, the amount of the high frequency signal boost can be adjusted depending on the loss of the channel. HSPICE simulations are used to demonstrate the performance of the driver at 10, 20 and 40 Gbps data rates. At 40 Gbps, the driver is capable of equalizing a PRBS9 data pattern signal through a channel that has a loss of 9 dB. At worst case conditions and 40 Gbps date rate, the driver achieves a differential eye-opening amplitude of 201 mVppd and an eye-opening of 0.952 UI. The driver is designed using 28 nm CMOS process and uses a nominal 1 V supply voltage. It consumes a maximum of 12 mW of at-speed power.     

Analysis of Handover Performance in LTE Femtocells Network

Handover management is one of the main factors representing the effectiveness of every wireless network technology. Due to the special characteristics of a femtocell, unnecessary handover occurs more frequently. This issue has attracted interest in developing a new handover algorithm in femtocell network. The standard handover algorithm relies on Reference Signal Received Power or Reference Signal Received Quality (RSRQ) level. However, this technique causes an unnecessary handover and reduces the user throughput. Mobility prediction is one of a popular technique to be implemented in handover algorithm. This paper analyzes the handover performance in femtocell network by using two types of handover algorithm which are standard A2-A4-RSRQ handover algorithm and proposed prediction handover algorithm. The analysis is performed in terms of the number of handover, the number of unnecessary handover, and the user throughput. The root cause of user throughput degradation is also analyzed. The results show that the prediction handover algorithm provides better performance than the A2-A4-RSRQ handover algorithm in terms of the number of handover and user throughput.     

Optical Properties of K<Subscript>2</Subscript>O-Li<Subscript>2</Subscript>O-WO<Subscript>3</Subscript>-B<Subscript>2</Subscript>O<Subscript>3</Subscript> Glasses: Evidence of Mixed Alkali Effect

Glass with compositions xK₂O-(30 ? x)Li₂O-10WO₃-60B₂O₃ for 0 ≤ x ≤ 30 mol.% have been prepared using the normal melt quenching technique. The optical reflection and absorption spectra were recorded at room temperature in the wavelength range 300–800 nm. From the absorption edge studies, the values of the optical band gap (E _opt) and Urbach energy (ΔE) have been evaluated. The values of E _opt and ΔE vary non-linearly with composition parameter, showing the mixed alkali effect. The dispersion of the refractive index is discussed in terms of the single oscillator Wemple Di-Domenico model.     

Job search website for illiterate users of Pakistan

Illiteracy is a major hurdle in socio-economic development of Pakistan. Research in the Information and Communication Technology (ICT) can help in tackling this issue by developing solutions tailored for illiterate population. The work presented within this paper proposes a job search website for illiterate population of KPK province of Pakistan. The designed website does not require any human assistance while searching a job. Moreover, the website uses culturally relevant graphical and audio content. The usability of the website is tested according to the ISO-9241-11 specification. Furthermore, we have studied the effect of the participants’ characteristics, i.e., their age, computer and mobile usage experience on the usability of the website. The results show that the participants found the website usable. Specifically, they could search suitable jobs with a minimal number of clicks and in less time as compared to the usual task completion rates reported throughout the literature. None of the participants’ characteristics were found to be affecting the usability of the website. These results suggest a promising potential of ICT solutions for providing services to illiterate population of Pakistan.