scholarly journals Transmission Delay-Based Uplink Multi-User Scheduling in IEEE 802.11ax Networks

2021 ◽  
Vol 11 (19) ◽  
pp. 9196
Author(s):  
Yonggang Kim ◽  
Gyungmin Kim ◽  
Youngwoo Oh ◽  
Wooyeol Choi
Keyword(s):  
Research Area ◽  
Network Throughput ◽  
Transmission Delay ◽  
User Scheduling ◽  
Throughput Performance ◽  
Research Attention ◽  
Transmission Delays ◽  
Ieee 802.11Ax ◽  
Excessive Competition ◽  
Scheduling Method

As the demands for uplink traffic increase, improving the uplink throughput has attracted research attention in IEEE 802.11 networks. To avoid excessive competition among stations and enhance the uplink throughput performance, the IEEE 802.11ax standard supports uplink multi-user transmission scenarios, in which AP triggers certain stations in a network to transmit uplink data simultaneously. The performance of uplink multi-user transmissions highly depends on the scheduler, and station scheduling is still an open research area in IEEE-802.11ax-based networks. In this paper, we propose a transmission delay-based uplink multi-user scheduling method. The proposed method consists of two steps. In the first step, the proposed method makcreateses station clusters so that stations in each cluster have similar expected transmission delays. The transmission delay-based station clustering increases the ues of uplink data channels during the uplink multi-user transmission scenario specified in IEEE 802.11ax. In the second step, the proposed method selects cluster for uplink multi-user transmissions. The cluster selection can be performed with a proportional fair-based approach. With the highly channel-efficient station cluster, the proposed scheduling method increases network throughput performance. Through the IEEE 802.11ax standard compliant simulations, we verify the network throughput performance of the proposed uplink scheduling method.

25 Years (1988-2012) of Freshwater Research in the Philippines: What has been done and what to do next?

2017 ◽  
Vol 11 (1) ◽  
Keyword(s):  
Current Knowledge ◽  
Critical Evaluation ◽  
Research Area ◽  
The Philippines ◽  
Freshwater Ecosystems ◽  
Steady Increase ◽  
Freshwater Biodiversity ◽  
Research Attention ◽  
Freshwater Systems ◽  
Tropical Asia

Globally, declines in freshwater biodiversity have been recognized to be far greater than those in marine or terrestrial realms. And like the rest of tropical Asia, the Philippine freshwater ecosystems and their biodiversity have been neglected. Our goals in this review are to provide indications where further research is needed, what systems are underrepresented and which organisms have been neglected. In this study, we determined the current knowledge on freshwater ecosystems in the country through critical evaluation of available peer-reviewed literature. A structured search on studies on Philippine freshwater systems published from January 1988 to December 2012 was performed using the Thomson Reuter’s Web of Science and Zoological Records. A total of 281 papers that have directly assessed Philippine freshwater systems and/or have actually collected and examined aquatic organisms from these systems were included in the review. More than 70% of the papers were produced solely by local researchers or with international collaborators. There was a significant steady increase in Philippine freshwater studies, with systematics (105 papers) and freshwater fish (78 papers) being the most frequently studied research area and organism, respectively. Rivers (116 studies) and lakes (112 studies) are still the most frequently studied freshwater systems. Among the papers reviewed, Luzon freshwater systems were the focus of most studies with Laguna de Bay being the most researched. Freshwater systems in the Visayas and Mindanao received little research attention. Finally, we presented a four-point research agenda, the results of which could form the basis for policy or management decisions to aid future conservation and sustainable management of freshwater ecosystems and their biodiversity in the Philippines.

Modeling attitude constructs in movie product placements

2014 ◽  
Vol 23 (7) ◽  
pp. 516-531 ◽  
Author(s):  
Siva K. Balasubramanian ◽  
Hemant Patwardhan ◽  
Deepa Pillai ◽  
Kesha K. Coker
Keyword(s):  
Conceptual Framework ◽  
Structural Equation ◽  
Research Area ◽  
Product Placement ◽  
Equation Model ◽  
Equation Modeling ◽  
Future Research ◽  
Research Attention ◽  
Content Type ◽  
Product Placements

Purpose – The purpose of this paper is to propose and test a conceptual framework of attitudinal constructs that influence attitude toward the brand in movie product placements. Advertising literature is replete with studies on factors that influence attitude toward the brand (Ab). However, this topic remains under-explored for product placements. Design/methodology/approach – Our framework showcases several theories to relate attitude and fit constructs to attitudes toward the product placement and attitude toward the brand. We use the structural equation model approach to estimate the conceptual framework. Findings – Several attitudinal movie constructs (attitude toward the actor, the character and the movie) influence attitude toward the product placement, which in turn mediates the relationship between the former attitudinal constructs and attitude toward the brand. Interestingly, only the fit between the actor and placed brand impacted attitude toward the product placement, with no effects found for the fit between the character and the fit between the movie and brand and the attitude toward the product placement. Research limitations/implications – We focus on explicit attitudes; implicit attitudes need future research attention. Practical implications – Findings affirm a key role for the actor featured in the placement in directly or indirectly shaping the attitude toward the brand. Originality/value – This is the first study to apply the structural equation modeling approach to this research area.

scholarly journals Dynamics of multiple interacting excitatory and inhibitory populations with delays

2018 ◽  
Author(s):  
Christopher M. Kim ◽  
Ulrich Egert ◽  
Arvind Kumar
Keyword(s):  
Stationary State ◽  
Network Model ◽  
Transmission Delay ◽  
Network Activity ◽  
Oscillatory Activity ◽  
Bifurcation Structure ◽  
Transmission Delays ◽  
Spiking Network ◽  
Frequency Coupling ◽  
Cross Frequency Coupling

A network consisting of excitatory and inhibitory (EI) neurons is a canonical model for understanding cortical network activity. In this study, we extend the EI network model and investigate how its dynamical landscape can be enriched when it interacts with another excitatory (E) population with transmission delays. Through analysis and simulations of a rate model and a spiking network model, we study the transition from stationary to oscillatory states by analyzing the Hopf bifurcation structure in terms of two network parameters: 1) transmission delay between the EI subnetwork and the E population and 2) inhibitory couplings that induce oscillatory activity in the EI subnetwork. We find that the critical coupling strength can strongly modulate as a function of transmission delay, and consequently the stationary state is interwoven intricately with oscillatory states generating different frequency modes. This leads to the emergence of an isolated stationary state surrounded by multiple oscillatory states and cross-frequency coupling develops at the bifurcation points. We identify the possible network motifs that induce oscillations and examine how multiple oscillatory states come together to enrich the dynamical landscape.

Techniques for Exploiting Mobility in Wireless Sensor Networks

2009 ◽  
pp. 445-455 ◽  
Author(s):  
Ataul Bari ◽  
Arunita Jaekel
Keyword(s):  
Sensor Networks ◽  
Sensor Network ◽  
Network Performance ◽  
Research Area ◽  
Sensor Nodes ◽  
Mobile Nodes ◽  
Open Problems ◽  
Research Attention ◽  
Future Work ◽  
Collaborative Efforts

A sensor network consists of tiny, low-powered and multifunctional sensor devices and is able to perform complex tasks through the collaborative efforts of a large number of sensor nodes that are densely deployed within the sensing field. Maintaining connectivity and maximizing the network lifetime are among the critical considerations in designing sensor networks and its protocols. Conservation of limited energy reserves at each sensor node is one of the greatest challenges in a sensor network. It has been suggested that mobility of some nodes/entities in a sensor network can be exploited to improve network performance in a number of areas, including coverage, lifetime, connectivityy, and fault-tolerance. In this context, techniques for effectively utilizing the unique capabilities of mobile nodes have been attracting increasing research attention in the past few years. In this chapter, the authors focus on some of the new and innovative techniques that have been recently proposed to handle a number of important problems in this field. It also presents a number of open problems and some developing trends and directions for future work in this emerging research area.

scholarly journals Colorectal Cancer Outcome Prediction from H&E Whole Slide Images using Machine Learning and Automatically Inferred Phenotype Profiles

10.29007/n912 ◽  
2019 ◽  
Author(s):  
Xingzhi Yue ◽  
Neofytos Dimitriou ◽  
Peter Caie ◽  
David Harrison ◽  
Ognjen Arandjelovic
Keyword(s):  
Colorectal Cancer ◽  
Machine Learning ◽  
Health Informatics ◽  
Digital Pathology ◽  
Health Impact ◽  
Research Area ◽  
Real World Data ◽  
Data Set ◽  
Research Attention ◽  
Cancer Outcome

Digital pathology (DP) is a new research area which falls under the broad umbrella of health informatics. Owing to its potential for major public health impact, in recent years DP has been attracting much research attention. Nevertheless, a wide breadth of significant conceptual and technical challenges remain, few of them greater than those encountered in digital oncology. The automatic analysis of digital pathology slides of cancerous tissues is particularly problematic due to the inherent heterogeneity of the disease, extremely large images, and numerous others. In this paper we introduce a novel machine learning based framework for the prediction of colorectal cancer outcome from whole haematoxylin & eosin (H&E) stained histopathology slides. Using a real-world data set we demonstrate the effectiveness of the method and present a detailed analysis of its different elements which corroborate its ability to extract and learn salient, discriminative, and clinically meaningful content.

scholarly journals Vehicular Networks Performance Evaluation Based on Downlink Scheduling Algorithms for High-Speed Long Term Evolution – Vehicle

2021 ◽  
Vol 15 (21) ◽  
pp. 52
Author(s):  
Hussain Mahdi ◽  
Baidaa Al-Bander ◽  
Mohammed Hasan Alwan ◽  
Mohammed Salah Abood ◽  
Mustafa Maad Hamdi
Keyword(s):  
Spectrum Sharing ◽  
High Speed ◽  
Data Exchange ◽  
Scheduling Algorithms ◽  
Long Term Evolution ◽  
User Scheduling ◽  
Time Data ◽  
Throughput Performance ◽  
Term Evolution

<p class="Abstract"><span lang="EN-US">Moving is the key to modern life. Most things are in moving such as vehicles and user mobiles, so the need for high-speed wireless networks to serve the high demand of the wireless application becomes essential for any wireless network design. The use of web browsing, online gaming, and on-time data exchange like video calls as an example means that users need a high data rate and fewer error communication links. To satisfy this, increasing the bandwidth available for each network will enhance the throughput of the communication, but the bandwidth available is a limited resource which means that thinking about techniques to be used to increase the throughput of the network is very important. One of the techniques used is the spectrum sharing between the available networks, but the problem here is when there is no available channel to connect with. This encourages researchers to think about using scheduling as a technique to serve the high capacity on the network. Studying scheduling techniques depends on the Quality-of-Service (QoS) of the network, so the throughput performance is the metric of this paper. In this paper, an improved Best-CQI scheduling algorithm is proposed to enhance the throughput of the network. The proposed algorithm was compared with three </span><span lang="MS">user scheduling algorithms to evaluate the throughput performance which are Round Robin (RR), Proportional Fair (PF), and Best-CQI algorithms. The study is performed under Line-of-Sight (LoS) link at carrier frequency 2.6 GHz to satisfy the Vehicular Long Term Evolution (LTE-V) with the high-speed scenario. The simulation results show that the proposed algorithm outperforms the throughput performance of the other algorithms.</span></p>

Analysis of forward approach for upper bounding end-to-end transmission delays over distributed real-time avionics networks

2020 ◽  
Vol 124 (1279) ◽  
pp. 1399-1435
Author(s):  
Q. Xu ◽  
X. Yang
Keyword(s):  
Real Time ◽  
Upper Bound ◽  
Data Exchange ◽  
Direct Consequence ◽  
Transmission Delay ◽  
Worst Case ◽  
Engineering Research ◽  
Transmission Delays ◽  
Global Clock ◽  
End To End

ABSTRACTDistributed real-time avionics networks have been subjected to a great evolution in terms of functionality and complexity. A direct consequence of this evolution is a continual growth of data exchange. AFDX standardised as ARINC 664 is chosen as the backbone network for those distributed real-time avionics networks as it offers high throughput and does not require global clock synchronisation. For certification reasons and engineering research, a deterministic upper bound of the end-to-end transmission delay for packets of each flow should be guaranteed. The Forward Approach (FA) is proposed for the computation of the worst-case end-to-end transmission delay. This approach iteratively estimates the maximum backlog (amount of the pending packets) in each visited switch along the transmission path, and the worst-case end-to-end transmission delay can be computed. Although it is pessimistic (overestimated), the Forward Approach can provide a tighter upper bound of the end-to-end transmission delay while considering the serialisation effect. Recently, our research finds the computation of the serialisation effect might induce an optimistic (underestimated) upper bound. In this paper, we analyse the pessimism in the Forward Approach and the optimism induced by the computation of the serialisation effect, and then we provide a new computation of the serialisation effect. We compare this new computation with the original one, the experiments show that the new computation reduces the optimism and the upper bound of the end-to-end transmission delay can be computed more accurately.

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