Octupolar Films with Large Second Harmonic Generation and Electro‐Optical Effects

Thin films that benefit from efficient octupolar molecular packing are prepared for second harmonic generation (SHG) and electro‐optic (EO) applications. The films are composed of 1,3,5‐tricyano‐2, 4,6‐tris(p‐diethylaminostyryl)benzene (TTB) in a ploymethylmetacrylate (PMMA) matrix on aluminum/BK7 glass (Al/BK7) and polyimide/indium tin oxide (PI/ITO) substrates. Octupolar films prepared on both substrates display polycrystalline and cylindrical domains. The molecular orientation, SHG efficiencies, and EO coefficients of the crystalline domains are measured. In the cylinders, the molecular crystal planes are oriented perpendicularly to the major cylinder axis, whereas in the polycrystals, the planes are randomly oriented. While both structures exhibit high and stable SHG and EO efficiencies, the cylinders, in particular, exhibited a very large SHG, a large EO coefficient, and high thermal stability; these characteristics will be useful in second order nonlinear optical applications.     

Virtual-node-based multicast routing and wavelength assignment in sparse-splitting optical networks

This paper investigates several problems associated with optical multicast routing and wavelength assignment in sparse-splitting optical networks for interactive real-time media distribution. Unfortunately, the constrained multicast routing with optimized wavelength assignment leads to NP-complete condition. Thus, in this paper, a virtual-node-based multicast routing algorithm is first proposed to satisfy the requirements of interactive real-time multicasting as well as the constraints from underlying optical networks. For the constructed multicast tree, we then associate an effective wavelength assignment algorithm. The experimental results show that the proposed algorithm combination performs well in terms of (1) the wavelength channel cost, (2) the maximum variation of inter-destination node delays, (3) the signal quality, and (4) the number of wavelength conversions.     

Instruction‐Level Power Estimator for Sensor Networks

In sensor networks, analyzing power consumption before actual deployment is crucial for maximizing service lifetime. This paper proposes an instruction‐level power estimator (IPEN) for sensor networks. IPEN is an accurate and fine grain power estimation tool, using an instruction‐level simulator. It is independent of the operating system, so many different kinds of sensor node software can be simulated for estimation. We have developed the power model of a Micaz‐compatible mote. The power consumption of the ATmega128L microcontroller is modeled with the base energy cost and the instruction overheads. The CC2420 communication component and other peripherals are modeled according to their operation states. The energy consumption estimation module profiles peripheral accesses and function calls while an application is running. IPEN has shown excellent power estimation accuracy, with less than 5% estimation error compared to real sensor network implementation. With IPEN's high precision instruction‐level energy prediction, users can accurately estimate a sensor network's energy consumption and achieve fine‐grained optimization of their software.     

Intelligent process analytics for CRM

Many organisations use decision models in their processes such as tables or trees to provide decision support to their operational divisions. For example, in fault management, customer contact centre operators usually use a decision model in the form of prescribed interviews. Based on the answers given by customers, the operator navigates through the decision model to reach an assessment of the problem. In order to achieve customer satisfaction and operational excellence, it is very important to constantly monitor the performance of a decision model not only on an overall level, but also on the level of individual decisions. In this paper we present a configurable business process analytics tool, known as the intelligent Universal Service Management System, that constantly monitors decision data and is capable of optimising the decisions based on high-level business objectives. We explain the various features of the software and show how it can be used to optimise decision processes. We also show how we can easily provide a customised version to monitor the performance of provision processes.     

Design of flexible GF(2/sup m/) elliptic curve cryptography processors

The design of flexible elliptic curve cryptography processors (ECP) is considered in this paper. Novel word-level algorithms and implementations for the underlying GF(2/sup m/) multiplication and squaring arithmetic which enable improved flexibility versus performance tradeoffs, are presented and employed in the design of an efficient flexible ECP architecture; corresponding field-programmable gate-array (FPGA) prototyping results for two different processor word lengths are also included for evaluation.     

Placement for large-scale floating-gate field-programable analog arrays

Modern advances in reconfigurable analog technologies are allowing field-programmable analog arrays (FPAAs) to dramatically grow in size, flexibility, and usefulness. Our goal in this paper is to develop the first placement algorithm for large-scale floating-gate-based FPAAs with a focus on the minimization of the parasitic effects on interconnects under various device-related constraints. Our FPAA clustering algorithm first groups analog components into a set of clusters so that the total number of routing switches used is minimized and all IO paths are balanced in terms of routing switches used. Our FPAA placement algorithm then maps each cluster to a computational analog block (CAB) of the target FPAA while focusing on routing switch usage and balance again. Experimental results demonstrate the effectiveness of our approach.     

High‐Performance Dual‐Circularly Polarized Reflector Antenna Feed

This paper presents a high‐performance dual‐circularly polarized feed employing a dielectric‐filled circular waveguide. Novel features are incorporated in the proposed feed, such as a dielectric rod radiator for high gain and good impedance matching; dual quarter‐wave chokes for low axial ratio over wide angles and for low back radiation; an integrated septum polarizer; and two end‐launch‐type coaxial‐to‐waveguide transitions. The proposed feed shows excellent performance at 5.0 GHz to 5.2 GHz.     

Performance study of close-loop power control algorithms for acellular CDMA system

Performance of a reverse link code-division multiple-access (CDMA) system with fast close-loop power control algorithms is studied. It is found that if the fast close-loop power control algorithm functions effectively, the speed of the mobile unit is in the range such that its Doppler frequency is less than one tenth of the power control updating rate. This paper also proposes a new predictive power control algorithm with better performance in terms of system capacity than the conventional and adaptive step size algorithms. An increase in system capacity as high as 22% compared with the conventional algorithm can be achieved depending on the mobile velocity     

Combined beamforming with space-time block coding using double antenna array group

The performance of the combined beamforming of space-time block coding according to the number of antenna array groups has been analysed. CB/spl I.bar/STBC/spl I.bar/single array and CB/spl I.bar/STBC/spl I.bar/double array were compared under the condition of DOA and SNR. CB/spl I.bar/STBC/spl I.bar/double array is shown to have a stable performance independent of DOA and angular spread.