scholarly journals A Novel LT Scheme without Feedback Messages for IoT of Smart City Scenarios

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Shuang Wu ◽  
Qingyang Guan ◽  
Shanshan Li
Keyword(s):  
Smart City ◽  
Low Cost ◽  
Transmission Efficiency ◽  
Low Power Consumption ◽  
Lt Codes ◽  
High Transmission ◽  
Feedback Message ◽  
Negative Effect ◽  
Arq Schemes ◽  
Optimal Decoding

For IoTs of smart city scenarios always with the low cost, low power consumption, and high transmission delay properties, the traditional protocols based on feedback messages, e.g., the Automatic Repeat reQuest (ARQ) schemes, would dramatically affect the transmission efficiency. Therefore, the LT codes with only one feedback message in each entire coding process can be used to substitute the traditional protocols. As in many IoTs of smart city scenarios, the data must have both high transmission efficiency and timeliness requirements; thus, the negative effect of only the feedback message in each entire coding process cannot be neglected in such transmission environments. To enhance the transmission efficiency of such ensembles, a novel LT scheme without feedback messages is proposed in this paper. By presenting the definitions of optimal decoding overhead and recovery ratio per symbol, the optimal decoding overhead of LT codes can be found directly, then the encoding overhead of the encoder can be predesigned also. For this reason, the feedback messages in LT schemes can be removed. By using the proposed LT scheme, the transmission efficiency of IoT of smart city scenarios can be enhanced.

Can Virtual Replace In-person Coaching? Experimental Evidence on Teacher Professional Development and Student Learning in South Africa

2021 ◽  
Author(s):  
Jacobus Cilliers ◽  
Brahm Fleisch ◽  
Janeli Kotzé ◽  
Nompumelelo Mohohlwane ◽  
Stephen Taylor ◽  
...  
Keyword(s):  
Professional Development ◽  
South Africa ◽  
Language Proficiency ◽  
Oral Language ◽  
Low Cost ◽  
Reading Proficiency ◽  
Home Language ◽  
Oral Language Proficiency ◽  
Virtual Coaching ◽  
Negative Effect

Virtual communication holds the promise of enabling low-cost professional development at scale, but the benefits of in-person interaction might be difficult to replicate. We report on an experiment in South Africa comparing on-site with virtual coaching of public primary school teachers. After three years, on-site coaching improved students' English oral language and reading proficiency (0.31 and 0.13 SD, respectively). Virtual coaching had a smaller impact on English oral language proficiency (0.12 SD), no impact on English reading proficiency, and an unintended negative effect on home language literacy. Classroom observations show that on-site coaching improved teaching practices, and virtual coaching led to larger crowding-out of home language teaching time. Implementation and survey data suggest technology itself was not a barrier to implementation, but rather that in-person contact enabled more accountability and support.

scholarly journals All-Optical Non-Inverted Parity Generator and Checker Based on Semiconductor Optical Amplifiers

2021 ◽  
Vol 11 (4) ◽  
pp. 1499
Author(s):  
Bingchen Han ◽  
Junyu Xu ◽  
Pengfei Chen ◽  
Rongrong Guo ◽  
Yuanqi Gu ◽  
...  
Keyword(s):  
Optical Amplifiers ◽  
Signal To Noise Ratio ◽  
Low Cost ◽  
Extinction Ratio ◽  
Semiconductor Optical Amplifiers ◽  
Optical Signal ◽  
Probe Light ◽  
All Optical ◽  
Negative Effect ◽  
Parity Generator

An all-optical non-inverted parity generator and checker based on semiconductor optical amplifiers (SOAs) are proposed with four-wave mixing (FWM) and cross-gain modulation (XGM) non-linear effects. A 2-bit parity generator and checker using by exclusive NOR (XNOR) and exclusive OR (XOR) gates are implemented by first SOA and second SOA with 10 Gb/s return-to-zero (RZ) code, respectively. The parity and check bits are provided by adjusting the center wavelength of the tunable optical bandpass filter (TOBPF). A saturable absorber (SA) is used to reduce the negative effect of small signal clock (Clk) probe light to improve extinction ratio (ER) and optical signal-to-noise ratio (OSNR). For Pe and Ce (even parity bit and even check bit) without Clk probe light, ER and OSNR still maintain good performance because of the amplified effect of SOA. For Po (odd parity bit), ER and OSNR are improved to 1 dB difference for the original value. For Co (odd check bit), ER is deteriorated by 4 dB without SA, while OSNR is deteriorated by 12 dB. ER and OSNR are improved by about 2 dB for the original value with the SA. This design has the advantages of simple structure and great integration capability and low cost.

Based on FPGA Intelligent Physiological Parameters Acquisition

2013 ◽  
Vol 344 ◽  
pp. 107-110
Author(s):  
Shun Ren Hu ◽  
Ya Chen Gan ◽  
Ming Bao ◽  
Jing Wei Wang
Keyword(s):  
High Speed ◽  
Low Cost ◽  
Physiological Parameters ◽  
Sensor Data ◽  
Low Power Consumption ◽  
Physiological Signal ◽  
Pulse Sensor ◽  
Monitoring Applications ◽  
Field Programmable ◽  
Design Ideas

For the physiological signal monitoring applications, as a micro-controller based on field programmable gate array (FPGA) physiological parameters intelligent acquisition system is given, which has the advantages of low cost, high speed, low power consumption. FPGA is responsible for the completion of pulse sensor, the temperature sensor, acceleration sensor data acquisition and serial output and so on. Focuses on the design ideas and architecture of the various subsystems of the whole system, gives the internal FPGA circuit diagram of the entire system. The whole system is easy to implement and has a very good promotional value.

MODE ANALYSIS AND SYSTEMATICAL DESIGN OF WIDE-BANDWIDTH PHOTONIC CRYSTAL 60° WAVEGUIDE BENDS WITH HIGH TRANSMISSION

2012 ◽  
Vol 26 (26) ◽  
pp. 1250170 ◽  
Author(s):  
TAO CHEN ◽  
CAILONG ZHENG ◽  
JINXING LI
Keyword(s):  
Photonic Crystal ◽  
Expansion Method ◽  
Transmission Efficiency ◽  
Slab Waveguide ◽  
Mode Analysis ◽  
Two Dimensional ◽  
Photonic Crystal Slab ◽  
High Transmission ◽  
Index Approach ◽  
Waveguide Bend

We present a procedure to enhance the transmission efficiency of a photonic crystal slab waveguide bend by introducing an air hole with the same radius at the center of bend and optimizing the positions of three neighboring holes in the corner. The improvement relies only on the method of displacing holes which is technologically preferred to controlling variations in hole size or shape. We employ the effective refractive index approach and two-dimensional plane wave expansion method to analyze the guide modes of the straight waveguide and waveguide bend. The transmission character of bent waveguides is investigated using two-dimensional finite-difference time-domain method. Numerical studies demonstrate that the approximate method of mode analysis is unsuitable to our model. Alternatively, we systematically study the effect of different positions of the holes on the transmission. The optimized bends for the high transmission with broad bandwidth are proposed.

The Research into the Key Problem of Multi-Channel Video Acquisition and Display System Based on FPGA

2012 ◽  
Vol 433-440 ◽  
pp. 5611-5615
Author(s):  
Jian Sheng Hu
Keyword(s):  
Power Consumption ◽  
Low Cost ◽  
Time Sequence ◽  
Good Effect ◽  
Low Power Consumption ◽  
Display System ◽  
Reading And Writing ◽  
Video Acquisition ◽  
System A ◽  
Time Division

Aimed at the problem of the embedded multi-channel video acquisition and display system, a new one based on FPGA is put forward. The configuration of the system is given. The principle and key issue is analyzed. Using of the state shift mechanism, t the controlling time sequence signals of TFT-LCD are produced; The synchronization among multi-channel video acquisition is realized by using time-division multiplexing technology; The problem of conflict between reading and writing frame cache is solved through the two SRAM switch; The frames composition technology is applied to accomplish the change from interlaced scanning to progressive scanning. The result of project application shows the virtues of system, such as good effect of acquisition and display, low cost and low power consumption.

Green Communication Infrastructure (GCI) Serving Different Smart City Applications

2021 ◽  
Vol 01 ◽  
Author(s):  
Qutaiba I. Ali ◽  
Issam Jafar
Keyword(s):  
Rural Areas ◽  
Smart City ◽  
Low Cost ◽  
System Level ◽  
Green Communication ◽  
Communication Infrastructure ◽  
Wide Range ◽  
The World ◽  
Self Powered ◽  
Application Fields

Aims: The aim of the Green Communication Infrastructure ‎‎(GCI) project is to understand the idea of a self ‎‎"sustainably" controlled correspondence foundation ‎fitting for smart city application fields. ‎ Background: This paper shows the endeavors to understand the idea of a ‎self "sustainably" energized communication foundation ‎fitting for smart city application fields. The recommended ‎Green Communication Infrastructure (CGI) comprises ‎different kinds of remote settled (or even versatile) hubs ‎performing diverse activities as per the application ‎requests. An imperative class of these hubs is the Wireless ‎Solar Router (WSR). Objective: The work in this venture was begun in 2009 with the aim ‎of demonstrating the essential advances that must be taken to ‎accomplish such framework and to proclaim the value of ‎embracing natural vitality assets in building mission ‎basic frameworks. Alternate destinations of this venture ‎are introducing a sensibly cost, solid, verified, and simple ‎to introduce correspondence foundation.‎ Method: The arrangement to actualize the GCI was accomplished ‎subsequent to passing two structure levels: device level and ‎system level. Result: The suggested system is highly applicable and serves a wide ‎range of smart city application fields and hence many ‎people and organizations can utilize this system. ‎ Conclusion: The presence of a reliable, secured, low cost, easy to install ‎and self-powered communication infrastructure is ‎mandatory in our nowadays. The communities in ‎developing countries or in rural areas need such a system ‎highly in order to communicate with other people in the ‎world which will affect positively their social and ‎economic situation.

Electroless plating process for the manufacture of radiation protection suits for pregnant woman: Effect of bending on its electromagnetic shielding performance

2022 ◽  
pp. 152808372110682
Author(s):  
Chengmei Gui ◽  
Di Sun ◽  
Wenya Liu ◽  
Haodong Ma ◽  
Zhenming Chen ◽  
...  
Keyword(s):  
Pregnant Woman ◽  
Radiation Protection ◽  
Noble Metals ◽  
Low Cost ◽  
Fiber Surface ◽  
Electroless Nickel ◽  
Electromagnetic Shielding ◽  
Shielding Effectiveness ◽  
Blend Fiber ◽  
Negative Effect

Multi-ion fabrics (especially silver ion fabrics) have special advantages as electromagnetic radiation, but the use of noble metals enhances its cost. Electroless nickel plating (EP-Ni) has great potential application in fabricating low-cost metallized material. Here, EP-Ni on pure cotton surface to fabricate radiation protection suits for pregnant woman was established to replace traditional protection suits with silver film. The active groups on the cotton/polyester blend fiber surface could absorb tin and palladium ions, acting as catalytic centers, which can catalyze the reduction of Ni2+ in the plating solution. Ni particle with (111) crystal plane preferential oriented crystal structure deposited on cotton surface with a coarse microstructure. The Ni deposited amount is about 19%. The fabricated material exhibited a shielding effectiveness of 29.5 dB. Studies also shown that bending has no negative effect on crystallinity and electrical property. But more bending times could lead to crack, which would decline electromagnetic shielding performance by 24%.

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