Adaptive Design for 2D Optical Coding PON Link Health Detection System in Complex Environment

2020 ◽  
Vol 38 (23) ◽  
pp. 6458-6464
Author(s):  
Zhiqun Ge ◽  
Tao Lv ◽  
Xiaokai Ye ◽  
Yu Zheng ◽  
Zhengying Xu ◽  
...  
2020 ◽  
Vol 17 (2) ◽  
pp. 558-569
Author(s):  
Areej Ghazi Abdulshaheed ◽  
Mohamed Bin Hussein ◽  
Mohd Azuwan Mat Dzahir ◽  
Shaharil Mad Saad ◽  
Rohani Othman

The flexibility of the snake robot body and its ability to adapt to different types of terrain attracted the attention of researchers to the great possibilities of its application in inspection, rescue, and searching tasks. These tasks require the robot to have the ability to navigate smartly in a complex environment (CE), which is considered to be one of the most critical challenges in the robotics field. The robot should be able to sense the surrounding environment and overcome different types of obstacles. In this paper, we have presented a review of the different type of snake robot locomotion and the controlling strategies in an environment with obstacles. We focus on avoidance obstacle locomotion as it is considered to be the most common strategy for dealing with obstacles. In addition, various types of modeling and controlling of locomotion with the presence of obstacles are discussed. Finally, a recommendation on the introduction of an obstacle detection system (ODS) and sensor fusion technology is given.


2012 ◽  
Vol 605-607 ◽  
pp. 1063-1067
Author(s):  
Xian Jun Yi ◽  
Jun Xia Jiang ◽  
De Wen Guo ◽  
Di Feng Zhang

Communications equipments' voltage, current fluctuations and power changes will bring uncertain hazards in communication systems, monitoring each functional unit's power is necessary. However, communication equipment's power supply has characteristics such as high transient and wide-scale fluctuations, which increases the difficulty of monitoring the power output. This paper introduces a design of an accurate real-time detection of each functional unit's power in communications equipment. The design uses dedicated power detection chip LTC4151 as the core components of the power collection, the LTC4151 which has wide range and high DC voltage input can measure output power, determine and make alarm processing under the management of the micro-controller. The hardware and software design of system are described in detail. The design has high reliability which solved the problem of monitoring communication equipment's power under the complex environment with simple circuit.


Author(s):  
J. B. Warren

Electron diffraction intensity profiles have been used extensively in studies of polycrystalline and amorphous thin films. In previous work, diffraction intensity profiles were quantitized either by mechanically scanning the photographic emulsion with a densitometer or by using deflection coils to scan the diffraction pattern over a stationary detector. Such methods tend to be slow, and the intensities must still be converted from analog to digital form for quantitative analysis. The Instrumentation Division at Brookhaven has designed and constructed a electron diffractometer, based on a silicon photodiode array, that overcomes these disadvantages. The instrument is compact (Fig. 1), can be used with any unmodified electron microscope, and acquires the data in a form immediately accessible by microcomputer.Major components include a RETICON 1024 element photodiode array for the de tector, an Analog Devices MAS-1202 analog digital converter and a Digital Equipment LSI 11/2 microcomputer. The photodiode array cannot detect high energy electrons without damage so an f/1.4 lens is used to focus the phosphor screen image of the diffraction pattern on to the photodiode array.


Author(s):  
P. Trebbia ◽  
P. Ballongue ◽  
C. Colliex

An effective use of electron energy loss spectroscopy for chemical characterization of selected areas in the electron microscope can only be achieved with the development of quantitative measurements capabilities.The experimental assembly, which is sketched in Fig.l, has therefore been carried out. It comprises four main elements.The analytical transmission electron microscope is a conventional microscope fitted with a Castaing and Henry dispersive unit (magnetic prism and electrostatic mirror). Recent modifications include the improvement of the vacuum in the specimen chamber (below 10-6 torr) and the adaptation of a new electrostatic mirror.The detection system, similar to the one described by Hermann et al (1), is located in a separate chamber below the fluorescent screen which visualizes the energy loss spectrum. Variable apertures select the electrons, which have lost an energy AE within an energy window smaller than 1 eV, in front of a surface barrier solid state detector RTC BPY 52 100 S.Q. The saw tooth signal delivered by a charge sensitive preamplifier (decay time of 5.10-5 S) is amplified, shaped into a gaussian profile through an active filter and counted by a single channel analyser.


Author(s):  
Huang Min ◽  
P.S. Flora ◽  
C.J. Harland ◽  
J.A. Venables

A cylindrical mirror analyser (CMA) has been built with a parallel recording detection system. It is being used for angular resolved electron spectroscopy (ARES) within a SEM. The CMA has been optimised for imaging applications; the inner cylinder contains a magnetically focused and scanned, 30kV, SEM electron-optical column. The CMA has a large inner radius (50.8mm) and a large collection solid angle (Ω > 1sterad). An energy resolution (ΔE/E) of 1-2% has been achieved. The design and performance of the combination SEM/CMA instrument has been described previously and the CMA and detector system has been used for low voltage electron spectroscopy. Here we discuss the use of the CMA for ARES and present some preliminary results.The CMA has been designed for an axis-to-ring focus and uses an annular type detector. This detector consists of a channel-plate/YAG/mirror assembly which is optically coupled to either a photomultiplier for spectroscopy or a TV camera for parallel detection.


Author(s):  
G.F. Bastin ◽  
H.J.M. Heijligers

Among the ultra-light elements B, C, N, and O nitrogen is the most difficult element to deal with in the electron probe microanalyzer. This is mainly caused by the severe absorption that N-Kα radiation suffers in carbon which is abundantly present in the detection system (lead-stearate crystal, carbonaceous counter window). As a result the peak-to-background ratios for N-Kα measured with a conventional lead-stearate crystal can attain values well below unity in many binary nitrides . An additional complication can be caused by the presence of interfering higher-order reflections from the metal partner in the nitride specimen; notorious examples are elements such as Zr and Nb. In nitrides containing these elements is is virtually impossible to carry out an accurate background subtraction which becomes increasingly important with lower and lower peak-to-background ratios. The use of a synthetic multilayer crystal such as W/Si (2d-spacing 59.8 Å) can bring significant improvements in terms of both higher peak count rates as well as a strong suppression of higher-order reflections.


Author(s):  
G. W. Hacker ◽  
I. Zehbe ◽  
J. Hainfeld ◽  
A.-H. Graf ◽  
C. Hauser-Kronberger ◽  
...  

In situ hybridization (ISH) with biotin-labeled probes is increasingly used in histology, histopathology and molecular biology, to detect genetic nucleic acid sequences of interest, such as viruses, genetic alterations and peptide-/protein-encoding messenger RNA (mRNA). In situ polymerase chain reaction (PCR) (PCR in situ hybridization = PISH) and the new in situ self-sustained sequence replication-based amplification (3SR) method even allow the detection of single copies of DNA or RNA in cytological and histological material. However, there is a number of considerable problems with the in situ PCR methods available today: False positives due to mis-priming of DNA breakdown products contained in several types of cells causing non-specific incorporation of label in direct methods, and re-diffusion artefacts of amplicons into previously negative cells have been observed. To avoid these problems, super-sensitive ISH procedures can be used, and it is well known that the sensitivity and outcome of these methods partially depend on the detection system used.


Author(s):  
Maoxu Qian ◽  
Mehmet Sarikaya ◽  
Edward A. Stern

It is difficult, in general, to perform quantitative EELS to determine, for example, relative or absolute compositions of elements with relatively high atomic numbers (using, e.g., K edge energies from 500 eV to 2000 eV), to study ELNES (energy loss near edge structure) signal using the white lines to determine oxidation states, and to analyze EXELFS (extended energy loss fine structure) to study short range ordering. In all these cases, it is essential to have high signal-to-noise (S/N) ratio (low systematical error) with high overall counts, and sufficient energy resolution (∽ 1 eV), requirements which are, in general, difficult to attain. The reason is mainly due to three important inherent limitations in spectrum acquisition with EELS in the TEM. These are (i) large intrinsic background in EELS spectra, (ii) channel-to-channel gain variation (CCGV) in the parallel detection system, and (iii) difficulties in obtaining statistically high total counts (∽106) per channel (CH). Except the high background in the EELS spectrum, the last two limitations may be circumvented, and the S/N ratio may be attained by the improvement in the on-line acquisition procedures. This short report addresses such procedures.


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