scholarly journals Impact of Inter-Gateway Distance on LoRaWAN Performance

Electronics ◽  
2021 ◽  
Vol 10 (18) ◽  
pp. 2197
Author(s):  
Bruno Citoni ◽  
Shuja Ansari ◽  
Qammer Hussain Abbasi ◽  
Muhammad Ali Imran ◽  
Sajjad Hussain
Keyword(s):  
Large Scale ◽  
Discrete Event ◽  
Comprehensive Analysis ◽  
Future Research ◽  
Network Simulator ◽  
Packet Collision ◽  
Set Up ◽  
The One ◽  
Best Fit

The large-scale behaviour of LoRaWAN networks has been studied through mathematical analysis and discrete-time simulations to understand their limitations. However, current literature is not always coherent in its assumptions and network setups. This paper proposes a comprehensive analysis of the known causes of packet loss in an uplink-only LoRaWAN network: duty cycle limitations, packet collision, insufficient coverage, and saturation of a receiver’s demodulation paths. Their impact on the overall Quality of Service (QoS) for a two-gateway network is also studied. The analysis is carried out with the discrete-event network simulator NS-3 and is set up to best fit the real behaviour of devices. This approach shows that increasing gateway density is only effective as the gateways are placed at a distance. Moreover, the trade-off between different outage conditions due to the uneven distribution of spreading factors is not always beneficial, diminishing returns as networks grow denser and wider. In particular, networks operating similarly to the one analysed in this paper should specifically avoid SF11 and 12, which decrease the average overall PDR by about 7% at 10% nodes increment across all configurations. The results of this work intend to homogenise behavioural assumptions and setups of future research investigating the capability of LoRaWAN networks and provide insight on the weight of each outage condition in a varying two-gateway network.

Analysis of the industrial quality of three sugarcane cultivars at “santa rosalía de la chontalpa” sugarcane mill

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Samuel Córdova-Sánchez ◽  
José Izquierdo-Hernández ◽  
Sergio Salgado-García ◽  
Luz del Carmen Lagunes-Espinoza ◽  
David Jesús Palma-López ◽  
...  
Keyword(s):  
Design Methodology ◽  
Reducing Sugars ◽  
Environmental Friendly ◽  
Linear Polynomial ◽  
Sugar Mills ◽  
Standard Values ◽  
Santa Rosalia ◽  
The One ◽  
Best Fit

Objective: To evaluate the industrial quality of three sugarcane cultivars in a template cycle at the supply area of “Santa Rosalía de la Chontalpa” sugarcane mill. Design / Methodology / Approach: An experiment was established under a factorial design 3x3 (3 cultivars: CP 72-2086, MEX 79-431 and MEX 69-290; x 3 sampling dates: 330, 390 and 450 DDS, Spanish equivalent for days after sowing) on an Eutric Fluvisol soil. In each plantation, a sample of 10 stems with three replications was collected to determine the industrial quality by polarimetry. Results: The industrial quality of the evaluated cultivars only differed statistically in terms of the percentage of purity, MEX 79-431 was the one that presented the lowest value for this variable. At 450 DDS, the highest value was observed for °Brix (17.28), POL percentage (14.92), purity (86.44%). The values obtained in the present study for the quality of juice in the evaluated cultivars are within the range of the standard values established for Mexico. Limitations / Implications: Polarimetry is still the method used by most of the sugar mills in Mexico, even if other more environmental-friendly methodologies exist. Findings / Conclusions: The trend line that best fit to MEX 69-290 and MEX 79-431, for °Brix, POL and purity, was a linear polynomial and to CP 72-2086, a polynomial quadratic. Fresh stems and reducing sugars showed best fit with an inverse polynomial. °Brix presented strong and positive correlation with POL (R = 0.99**); and strong and negative with reducer sugars (R = -0.95**) and fresh stem humidity (R = -0.91**).

scholarly journals Quality of learners at the start of each educational process

2019 ◽  
Vol 9 (14) ◽  
Author(s):  
Abdennasser Naji
Keyword(s):  
Control Systems ◽  
Preventive Measures ◽  
Educational Process ◽  
Service Needs ◽  
True Value ◽  
Previous Cycle ◽  
Set Up ◽  
The One

The education system is organized in the form of cycles, each feeding the one following it with learners. They will continue their studies in the destination cycle, and their future will certainly depend, at least in part, on the quality of the skills acquired in the previous cycle. Given the divergences and disparities existing between the different cycles mainly due to the fact that each responds to its own design logic and in the absence of coordination between them, there is a huge lack of quality to gain at the interface of the cycles . The referral system that plays the role of supply service needs to be updated to strengthen educational quality, but it is not the only one. It is also necessary to help the orienting staff to assess the quality of the learners at its true value, to set up partnership links between the cycles to help each other in favor of quality, and to set up reception control systems at the entry of each cycle, supported by corrective and preventive measures.

OPNET Simulation Setup for QoE Based Network Selection

2012 ◽  
pp. 100-139
Author(s):  
Umar Toseef ◽  
Manzoor Ahmed Khan
Keyword(s):  
User Satisfaction ◽  
Discrete Event ◽  
Mobile Terminal ◽  
Research Literature ◽  
User Preferences ◽  
Transport Infrastructure ◽  
Network Simulator ◽  
Component Development ◽  
Efficient Resource

In its most generic sense, the user-centric view in telecommunications considers that the users are free from subscription to any one network operator and can instead dynamically choose the most suitable transport infrastructure from the available network providers for their terminal and application requirements. In this approach, the decision of interface selection is delegated to the mobile terminal enabling end users to exploit the best available characteristics of different network technologies and network providers, with the objective of increased satisfaction. In order to more accurately express the user satisfaction in telecommunications, a more subjective and application-specific measure, namely, the Quality-of-Experience (QoE) is introduced. QoE is the core requirement in future wireless networks and provisions. It is a framework that optimizes the global system of networks and users in terms of efficient resource utilization and meeting user preferences (guaranteeing certain Quality-of-Service [QoS] requirements). A number of solution frameworks to address the mentioned problems using different theoretical approaches are proposed in the research literature. Such scholarly approaches need to be evaluated using simulation platforms (e.g., OPNET, NS2, OMNET++, etc.). This chapter focuses on developing the simulation using a standard discrete event network simulator, OPNET. It outlines the general development procedures of different components in simulation and details the following important aspects: Long Term Evolution (LTE) network component development, impairment entity development, implementing IPv6 flow management, developing an integrated heterogeneous scenario with LTE and WLAN, implementing an example scenario, and generating and analyzing the results.

Exploring the Role of Complexity, Content and Individual Differences in Aesthetic Reactions to Semi-Abstract Art Photographs

2020 ◽  
Vol 8 (1) ◽  
pp. 89-119
Author(s):  
Nathalie Vissers ◽  
Pieter Moors ◽  
Dominique Genin ◽  
Johan Wagemans
Keyword(s):  
Large Scale ◽  
A Priori ◽  
Data Driven ◽  
Future Research ◽  
Response Patterns ◽  
Online Study ◽  
Exploratory Data ◽  
Science Collaboration ◽  
Set Up ◽  
Different Response

Artistic photography is an interesting, but often overlooked, medium within the field of empirical aesthetics. Grounded in an art–science collaboration with art photographer Dominique Genin, this project focused on the relationship between the complexity of a photograph and its aesthetic appeal (beauty, pleasantness, interest). An artistic series of 24 semi-abstract photographs that play with multiple layers, recognisability vs unrecognizability and complexity was specifically created and selected for the project. A large-scale online study with a broad range of individuals (n = 453, varying in age, gender and art expertise) was set up. Exploratory data-driven analyses revealed two clusters of individuals, who responded differently to the photographs. Despite the semi-abstract nature of the photographs, differences seemed to be driven more consistently by the ‘content’ of the photograph than by its complexity levels. No consistent differences were found between clusters in age, gender or art expertise. Together, these results highlight the importance of exploratory, data-driven work in empirical aesthetics to complement and nuance findings from hypotheses-driven studies, as they allow to go further than a priori assumptions, to explore underlying clusters of participants with different response patterns, and to point towards new venues for future research. Data and code for the analyses reported in this article can be found at https://osf.io/2fws6/.

scholarly journals Improving the Activity of Fe/C/N ORR Electrocatalyst Using Double Ammonia Promoted CO2 Laser Pyrolysis

2020 ◽  
Vol 6 (4) ◽  
pp. 63
Author(s):  
Henri Perez ◽  
Mathieu Frégnaux ◽  
Emeline Charon ◽  
Arnaud Etcheberry ◽  
Olivier Sublemontier
Keyword(s):  
Co2 Laser ◽  
Large Scale ◽  
Laser Energy ◽  
Reduction Reaction ◽  
Laser Pyrolysis ◽  
Highly Active ◽  
One Step ◽  
Orr Activity ◽  
Set Up ◽  
The One

Recently, we reported the use of CO2 laser pyrolysis for the synthesis of promising Fe/C/N electrocatalysts for Oxygen Reduction Reaction (ORR) in fuel cells. The set-up used single laser pyrolysis of an aerosolized solution of iron acetylacetonate in toluene with ammonia, both as laser energy transfer agent and nitrogen source. In the present paper, we investigate the effect of a second ammonia promoted CO2 laser pyrolysis on the feature and ORR activity of Fe/C/N electrocatalysts. Indeed, compared to single pyrolysis, the second ammonia promoted CO2 laser pyrolysis could be an interesting way to synthesize in one-step performing ORR electrocatalysts on a large scale. For this comparison, a two-stage reactor was built, allowing both single ammonia-induced CO2 laser pyrolysis as reported previously or double ammonia-induced CO2 laser pyrolysis. In the latter configuration, the catalyst nanopowder flow is formed at the first stage of the reactor, then mixed with a second ammonia flow and allowed to cross a second CO2 laser beam, thus undergoing a second ammonia-induced CO2 laser pyrolysis before being collected on filters. It is found that the second ammonia-induced CO2 laser pyrolysis significantly improves the ORR performances of the materials prepared by single CO2 laser pyrolysis. The effect is demonstrated for three different catalysts for which the onset potentials for the ORR from single-stage to double-stage configuration increase from 625 mV to 845 mV, 790 mV to 860 mV, and 800 mV to 885 mV, respectively. The selectivity of the ORR was determined at 600 mV/SHE and lie between 3.41 and 3.72. These promising performances suggesting potentialities for the one-step formation of highly active Fe/C/N ORR electrocatalysts are discussed, based on results of surface analysis by XPS, specific surface area measurements, and Raman spectroscopy.

Africa — Latin America — Asia and Pacific — Middle East

1986 ◽  
Vol 26 (251) ◽  
pp. 115-124
Keyword(s):  
Latin America ◽  
Middle East ◽  
Large Scale ◽  
The Other ◽  
Displaced Persons ◽  
Assistance Programme ◽  
Medical Teams ◽  
Set Up ◽  
The One ◽  
Voluntary Agencies

In January and February, the ICRC reduced, as planned, the level of its relief activities in Ethiopia. This reduction was made possible, on the one hand, by an increase in food supplies for the population in the northern provinces of that country affected by conflict and drought and, on the other, by more intensive activity on the part of other voluntary agencies in the area. While leaving in place the structures which would enable it rapidly to set up a large-scale assistance programme if the need were to appear in a given region, the ICRC has lowered the volume of its general relief distributions. In December 1985, 10,700 tonnes were distributed to 830,000 persons. This was reduced to 5,000 tonnes for 424,300 persons in January, and further to 2,800 tonnes for 181,000 persons in February in the provinces of Eritrea, Tigray, Wollo, Gondar and Hararge. The last three therapeutic feeding centres were closed on 16 January (Wukro), and on 16 and 27 February (Idaga Hamus and Adwa). However, ICRC medical teams continued to monitor the health of the populations living in provinces which were receiving assistance, concentrating their activities on groups of displaced persons in Eritrea (in the region between Keren and Barentu), Tigray (in the region between Aksum and Adwa and the region of Mehony), Wollo (in the region of Sekota) and Hararge (Wobera Woreda; Habro Woreda), all areas with major security problems.

scholarly journals Optimising Differentiated Services Strategies under IMS

2018 ◽  
Vol 2 (3) ◽  
pp. 1-10
Author(s):  
David K. Osei-Aboagye ◽  
Peter S. Excell
Keyword(s):  
Mobile Communications ◽  
Network Architecture ◽  
Discrete Event ◽  
Differentiated Services ◽  
Main Concern ◽  
Network Architectures ◽  
Network Simulator ◽  
Core Network ◽  
Network Technologies

The evolving standards of mobile communications, the wide variety of services they offer and the rapid growth of the Internet have made a merger of the two network technologies inevitable. One of the most prominent platforms that has been developed to facilitate this is the IP Multimedia Subsystem (IMS) concept. Many mobile communications standards integrate IMS as the main core network architecture and Quality of Service (QoS) is the main concern for customer satisfaction. A major approach to optimisation of QoS is the Differentiated Services scheme, and a simulation study of implementations of this is presented. The study covered an IMS core network architecture modelled with discrete-event network simulator software, with a Differentiated Services QoS scheme run over it with differing bearer traffic scenarios. Implications for core network architectures are discussed.

QoS Oriented Enhancement based on the Analysis of Dynamic Job Scheduling in HPC

2014 ◽  
Vol 6 (4) ◽  
pp. 28-45 ◽  
Author(s):  
Reshmi Raveendran ◽  
D. Shanthi Saravanan
Keyword(s):  
Resource Allocation ◽  
Quality Of Service ◽  
High Performance ◽  
Large Scale ◽  
Job Scheduling ◽  
Dynamic Scheduling ◽  
Future Research ◽  
Dynamic Allocation ◽  
The Impact

With the advent of High Performance Computing (HPC) in the large-scale parallel computational environment, better job scheduling and resource allocation techniques are required to deliver Quality of Service (QoS). Therefore, job scheduling on a large-scale parallel system has been studied to minimize the queue time, response time, and to maximize the overall system utilization. The objective of this paper is to touch upon the recent methods used for dynamic resource allocation across multiple computing nodes and the impact of scheduling algorithms. In addition, a quantitative approach which explains a trend line analysis on dynamic allocation for batch processors is depicted. Throughout the survey, the trends in research on dynamic allocation and parallel computing is identified, besides, highlights the potential areas for future research and development. This study proposes the design for an efficient dynamic scheduling algorithm based on the Quality-of-Service. The analysis provides a compelling research platform to optimize dynamic scheduling of jobs in HPC.

QoS Oriented Enhancement based on the Analysis of Dynamic Job Scheduling in HPC

2016 ◽  
pp. 1800-1817
Author(s):  
Reshmi Raveendran ◽  
D. Shanthi Saravanan
Keyword(s):  
Resource Allocation ◽  
Quality Of Service ◽  
Large Scale ◽  
Job Scheduling ◽  
Dynamic Scheduling ◽  
Future Research ◽  
Dynamic Allocation ◽  
System Utilization ◽  
Batch Processors

With the advent of High Performance Computing (HPC) in the large-scale parallel computational environment, better job scheduling and resource allocation techniques are required to deliver Quality of Service (QoS). Therefore, job scheduling on a large-scale parallel system has been studied to minimize the queue time, response time, and to maximize the overall system utilization. The objective of this paper is to touch upon the recent methods used for dynamic resource allocation across multiple computing nodes and the impact of scheduling algorithms. In addition, a quantitative approach which explains a trend line analysis on dynamic allocation for batch processors is depicted. Throughout the survey, the trends in research on dynamic allocation and parallel computing is identified, besides, highlights the potential areas for future research and development. This study proposes the design for an efficient dynamic scheduling algorithm based on the Quality-of-Service. The analysis provides a compelling research platform to optimize dynamic scheduling of jobs in HPC.

A comparative judgment approach to assessing Chinese Sign Language interpreting

2021 ◽  
pp. 026553222110389
Author(s):  
Chao Han ◽  
Xiaoyan Xiao
Keyword(s):  
Sign Language ◽  
Comparative Judgment ◽  
Binary Outcomes ◽  
Future Research ◽  
Evidential Support ◽  
Valid Assessment ◽  
Novel Method ◽  
The One ◽  
Sign Language Interpreting

The quality of sign language interpreting (SLI) is a gripping construct among practitioners, educators and researchers, calling for reliable and valid assessment. There has been a diverse array of methods in the extant literature to measure SLI quality, ranging from traditional error analysis to recent rubric scoring. In this study, we want to expand the terrain of SLI assessment, by exploring and evaluating a novel method, known as comparative judgment (CJ), to assess SLI quality. Briefly, CJ involves judges to compare two like objects/items and make a decision by choosing the one with higher quality. The binary outcomes from repeated comparisons by a group of judges are then modelled statistically to produce standardized estimates of perceived quality for each object/item. We recruited 12 expert judges to operationalize CJ via a computerized system to assess the quality of Chinese Sign Language interpreting produced by 36 trainee interpreters. Overall, our analysis of quantitative and qualitative data provided preliminary evidential support for the validity and utility of CJ in SLI assessment. We discussed these results in relation to previous SLI literature, and suggested future research to cast light on CJ’s usefulness in applied assessment contexts.

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