Performance of Efficient Signal Detection for LED-ID Systems

In this paper, effects of reader-to-reader interference are investigated for LED identification (LED-ID) system in a multi-reader environment. The LED-ID readers typically use different channels to avoid collision between readers. However, in-channel collision usually happens in terms of interrogation range. A reader-to-reader interference scenario is proposed, and nominal interrogation range of a desired reader is derived from this model. In order to evaluate the LED-ID reader-to-reader interference quantitatively, an efficient detection scheme is proposed and simulated by employing spreading sequence. The spreading sequence is inserted between each user’s frame formats. In the receiver, the desired signal is detected by using correlation among inserted spreading sequences. From simulation results, it is confirmed that the proposed scheme is very effective to enhance reliability of LED-ID communication systems.     

A Review of Three‐Dimensional Resistive Switching Cross‐Bar Array Memories from the Integration and Materials Property Points of View

Issues in the circuitry, integration, and material properties of the two‐dimensional (2D) and three‐dimensional (3D) crossbar array (CBA)‐type resistance switching memories are described. Two important quantitative guidelines for the memory integration are provided with respect to the required numbers of signal wires and sneak current paths. The advantage of 3D CBAs over 2D CBAs (i.e., the decrease in effect memory cell size) can be exploited only under certain limited conditions due to the increased area and layout complexity of the periphery circuits. The sneak current problem can be mitigated by the adoption of different voltage application schemes and various selection devices. These have critical correlations, however, and depend on the involved types of resistance switching memory. The problem is quantitatively dealt with using the generalized equation for the overall resistance of the parasitic current paths. Atomic layer deposition is discussed in detail as the most feasible fabrication process of 3D CBAs because it can provide the device with the necessary conformality and atomic‐level accuracy in thickness control. Other subsidiary issues related to the line resistance, maximum available current, and fabrication technologies are also reviewed. Finally, a summary and outlook on various other applications of 3D CBAs are provided.     

Poly(lactic acid) nanocomposites: comparison of their properties with montmorillonite and synthetic mica (II)

Our study was to clarify the intercalation of polymer chains to organoclays and to improve the thermo-mechanical properties. Two organoclays were synthesized. One was a montmorillonite modified with hexadecylamine (C₁₆-MMT); the other was a fluorinated-mica modified with hexadecylamine (C₁₆-Mica). Dispersions of organoclays with poly(lactic acid) (PLA) were by using the solution intercalation method at different organoclay contents to produce nano-scale composites. The maximum ultimate tensile strength was observed for blends containing 4 wt% of either of the two organoclays and decreased with further increases in the organoclay content. The initial modulus increased with increasing organoclay content up to 4 wt% for C₁₆-MMT. When the C₁₆-MMT content was greater than this critical wt%, the modulus of the hybrids started to decrease. In contrast, the initial modulus of the hybrids using C₁₆-Mica increased continually with increasing clay content from 2 to 8 wt%. The tensile properties of the C₁₆-Mica hybrids were higher than those of the hybrids containing C₁₆-MMT. The optical translucency was not affected by the organoclay content up to 6 wt%; however, the films containing 8 wt% organoclays were slightly more cloudy.     

A case report: cephalic replacement and emergency caesarean section for the resolution of shoulder dystocia

Shoulder dystocia is a serious complication of delivery. Various manoeuvres had been described, all aim at achieving shoulder descent and vaginal delivery. We report a case whereby shoulder dystocia was managed by a rather unique technique--the foetal head was replaced in the vagina and baby delivered by emergency Caesarean Section.     

Phase transformation of metastable beta Ti alloys with tweed structure

This paper presents the finding of a microstructural abnormality generated in the metastable phase of a supersaturated state, and compares the results with ordering behavior such as premartensitic transformation. A tweed structure consisting of the metastable phase was observed by transmission electron microscopy, and spot satellites inflicted by streaks were also observed in lattice diffraction. The present report also reviews a new phase transformation from the metastable phase caused by the processes of aging, sub-zero quenching, and induced strain or stress.     

Packing scheme for mean-filtering of an 8 bit image

Filtering is one of the most well known low-level image processing procedures. In most filtering procedures, the potential capability of an ALU in a processor is not fully used. The authors propose a packed mean filtering scheme. The scheme packs several pixels into a unit and processes them simultaneously. Experiments are held under three distinct machines to evaluate the performance of the scheme. The result shows that the scheme enhances processing speed in all three environments     

Critical Analysis of Computing Equations for Determination of BOD by Dilution Methods

The dilution method has been accepted widely as the standard procedure for determining biochemical oxygen demand (BOD). A mass-balance approach was used to analyze four equations for computing BOD: two involving external seed correction methods (Standard Methods) and two involving internal correction methods (Sawyer and McCarty in 1978 and Kline and Gibbs in 1979). Five testing conditions were identified as being pertinent to the underlying assumptions: seed addition method, uniform BOD bottle volume, uniform initial dissolved oxygen (DO), seed uptake linearity, and data handling method. The results of this study showed that internal methods may provide more reproducible results, primarily due to the inherent correction for dilution water demand and better data handling (regression) technique to cope with the variation in BOD bottle volume and initial DO. However, internal methods may violate the requirements imposed by Standard Methods for minimum final DO (1?mg/L) for the high spike runs and minimum 5?day DO depletion (2?mg/L) for the low spike runs. Recommendations are also made to improve the reliability of these methods.     

A flexible inspection cell for machined parts

This paper describes the development of a computer-aided vision system, in a flexible inspection cell, for checking the dimensional accuracy of machined parts. Most vision systems identify parts for which models are already reside in the database, whereas this particular system allows parts for which models are not available in the database to be checked. Also described in the paper is a feature-based approach which this system adopts for identifying the parts.     

Effects of organophilic‐modified attapulgite nanorods on thermal and mechanical behavior of segmented polyurethane elastomers

The effects of different grafting content of 4,4′‐methlenebis(phenyl isocyanate)‐modified attapulgite (ATT‐MDI) on thermal and mechanical properties of segmented polyurethane (PU) elastomers were investigated. The ATT‐MDI nanorods with different grafting content were prepared by treating ATT with heat and acid followed by grafting with MDI molecules. MDI‐modified ATT were characterized by transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy. TGA analysis revealed that at least 30 wt % of MDI was grafted/adsorbed on the surface of ATT following the modification. Three PU/ATT‐MDI nanocomposites were in situ synthesized using ATT with different grafting contents, and the materials were characterized by TEM, thermal analysis, and mechanical testing. The tensile strength and modulus increased with increasing grafting content of MDI molecules, and the crystallinity of soft and hard segments was increased by ATT‐MDI. POLYM. COMPOS., 31:1890–1898, 2010. © 2010 Society of Plastics Engineers.     

Fracture toughness of CFRP laminated plates according to resin content

CFRP(carbon fiber reinforced plastic) has recently found wide use in different industries. The material, however, is very prone to damage from collision with foreign objects. This study aims at finding Ĵ-integral in mode II for CFRP laminated plates based on classical bar theory for dynamic conditions in consideration of inertia forces and eventually to finding dynamic inter-layer fracture toughness. Dynamic inter-layer fracture toughness was observed using an in-house ENF (End Notched Flexure) experimental facility using Split Hopkinson’s Bar (SHPB). Also the variation of the fracture toughness depending on different resin contents and fiber arrangement in the CFRP specimen ([0°3/90°3/0°6/90°3/0°3], [0°20], [0°5/90°10/0°5]) was observed. It was established that under both quasi-static and dynamic load conditions, the critical load and the inter-layer fracture toughness increased sharply following the extension of the resin content. Thus, it may be concluded that the resin content is the major factor determining the inter-layer fracture toughness in the CFRP laminated plate.