RFID Transponder Collision Control Algorithm

Transponder collision problem can be significant when a large number of RFID (radio frequency identification) transponders exist in field. Most existing anti-collision algorithms can solve this problem. However, problem arises when all or part of these transponders are having identical UID (unique identification). This paper proposes a new transponder collision control algorithm to overcome overlapping that occurs among transponders with identical UID in RFID large scale deployment (e.g., in a large warehouse), so that the RFID reader can successfully identify the quantity of transponders for each particular UID with high identification accuracy. The proposed anti-collision algorithm adopts a modified version of frequency domain method by adding stochastic delays in time domain. The obtained results show that the proposed method can achieve optimum frequency bandwidth utilization and at the same time poses high identification accuracy (almost 100%) with low identification delay.     

Efficiency enhancement in organic solar cells by configuring hybrid interfaces with narrow bandgap PbSSe nanocrystals

We hereby present an incorporation technique for inorganic nanocrystals (NCs) in organic solar cells (OSCs) for the improvement of power conversion efficiency (PCE). Ternary PbSSe NCs constitute stable conformations with regular poly(3-hexylthiophene):phenyl-C₇₀ butyric acid methyl ester (P3HT:PCBM) organic composites under two heterojunction systems, and significant solar performance modification was obtained, depending on the incorporation type. Bilayer heterojunction (Bi-HJ) SCs, in which a pristine NC layer is sandwiched between the organic composite and cathode, showed significantly broadened photon-harvesting resulting from combination of both layers and energetic carrier transport as a result of reduced recombination losses. In contrast, bulk heterojunction (BHJ) SCs comprising combined composites of P3HT:PCBM:NCs in a single layer suffered from inefficient charge transport as a result of ubiquitous charge traps. Use of Bi-HJ cells with an NC layer of optimal thickness greatly enhanced the short-circuit current (J_SC) to 10.54 mA cm^?2 and a PCE of 3.12% was achieved; this is a 31% improvement over the conversion efficiency of purely organic cells without NCs. The separate PbSSe NC layer coupled well with the organic composite to provide a broad-range photon-harvesting ability and vertically efficient interfacial junctions for systematic charge transport; this greatly enhances the photovoltaic performances of the OSCs.     

Fine‐Grained FSMD Power Gating Considering Power Overhead

As a fine‐grained power gating method for achieving greater power savings, our approach takes advantage of the finite state machine with a datapath (FSMD) characteristic which shows sequential idleness among subcircuits. In an FSMD‐based power gating, while only an active subcircuit is expected to be turned on, more subcircuits should be activated due to the power overhead. To reduce the number of missed opportunities for power savings, we deactivated some of the turned‐on subcircuits by slowing the FSMD down and predicting its behavior. Our microprocessor experiments showed that the power savings are close to the upper bound.     

Computational analysis of the interfacial effect on electromigration in flip chip solder joints

Recent experiments have shown failure in flip chip micro solder joints induced by electromigration. This paper proposes a three-dimensional computational model to simulate the evolution of micro and sub-micro scale solder joints due to electromigration induced diffusion. The evolving morphology of the solder joint related with multiple mechanisms causes a computational challenge. This is addressed by employing a diffuse interface model with multiple concentrations. To efficiently resolve complications, a semi-implicit Fourier spectral scheme and a biconjugate-gradient method are adopted. Results have demonstrated rich dynamics and solder breakage at the interface on the cathode side. Furthermore, the effect of the designed interface region on the reliability of solder joints has been investigated with the developed model.     

柔性有源OLED显示器制造几点技术方面的考虑

AMOLED在柔性显示领域前途似锦。LG显示展示了一款全彩4in柔性AMOLED样机,衬底为80μm厚的不锈钢薄片,曲率达到5cm弯曲半径。本文就此项柔性显示技术所面临的挑战进行了探讨．包括柔性衬底衬底的传送、如何获得特性稳定可靠的TFT以使OLED的亮度和一致性适用于此项技术的商业化推广。     

Smart TDI readout circuit for long-wavelength IR detector

A smart time delay and integration (TDI) readout circuit is suggested which performs background suppression, cell-to-cell non-uniformity compensation, and dead pixel correction. Using the smart TDI readout circuit, the integration capacitor area occupying almost the whole area of a unit-cell can be reduced to one-fifth and transimpedance gain can increase by five times. From measurement results, it is found that the skimming current error for a few hundred nA background current is < 1.25 nA corresponding to LSB/2 of ADC and the non-uniformity introduced by cell-to-cell background current variation is reduced to 1.02 nA     

Simulation and design methodology for a 50-Gb/s multiplexer/demultiplexer package

A 50 Gb/s package for SiGe BiCMOS 4:1 multiplexer and 1:4 demultiplexer targeting SONET OC-768 serial communication systems is introduced in this work. The package was designed to facilitate bit-error-rate tests and constructed with high-speed coaxial connectors, transmission lines on ceramic substrate, ribbon bonds for chip-to-package interconnects, and a metal composite housing. Numerical simulations were conducted to guide the package design, and both small signal measurements and operational tests were performed thereafter to verify the design and modeling concepts. To keep the model structure under the existing computing capability, the simulation was segmented into three sections - coaxial connector to transmission line, transmission line alone, and transmission line to ribbon bond, and then the results were assembled to predict the performance of the entire package. The package was operated up to 50 Gb/s with low degradation to input digital waveforms and free of error.     

Characterization of picosecond electric-pulse propagation on CPW components by transient near-field mapping

For the first time, the picosecond electric-pulse propagation characteristics of a few coplanar waveguide (CPW) components, including transmission lines, capacitive open and short terminations and a right-angle bend, have been successfully measured by mapping the time-dependent tangential near-electric-field distributions. The measurement was performed using a two-dimensional photoconductive (PC) near-field mapping system incorporating a recently developed novel PC electric-field probe, which could measure the separate picosecond orthogonal electric-field components with minimal loading effects. The resulting field-images mapped over the structural capacitive open termination and the short termination, showed previously unknown, and quite remarkable, transient picosecond electric-pulse reflection phenomena, which cannot be measured using conventional test instruments. In addition, the images showed that reflection-phenomenon itself required about 1 ps of propagation delay, and that the pulse-reflection from the capacitive open-termination required additional time delay matched to the length of the open-gap between the two slots of the CPW.     

Signaling and Control Procedures Using Generalized MPLS Protocol for IP over an Optical Network

This paper reviews the existing research activities on signaling and control procedures for IP over optical networks. We focus on the IP‐centric signaling and control architecture based on the generalized multi‐protocol label switching (GMPLS) protocol and analyze various scenarios and technical issues for deploying the IP over an optical network. We analyze the signaling and operations and administration and maintenance requirements for integrating an IP network and an optical network in order to cope with the high bandwidth and poor resource granularity of the optical network, including the optical cross‐connect system. On the basis of network architecture and a reference configuration model, we investigate the GMPLS‐based control architecture and interconnection model appropriate for controlling IP bandwidth and optical lambda resources. The signaling and control procedure based on GMPLS on optical user‐network interface and network‐network interface are comparatively investigated to provide the optical lightpath. We also study protection and restoration procedures to protect link failure when it applies to GMPLS signaling.