Reducing Delay in Retrial Queues by Simultaneously Differentiating Service and Retrial Rates

2020 ◽  
Vol 68 (6) ◽  
pp. 1648-1667
Author(s):  
Jinting Wang ◽  
Zhongbin Wang ◽  
Yunan Liu
Keyword(s):  
Mobile Networks ◽  
Heavy Traffic ◽  
Inventory Systems ◽  
Service Systems ◽  
Retrial Queues ◽  
Complex Nature ◽  
Service Capacity ◽  
Asymptotic Reduction ◽  
Additional Service ◽  
The Impact

Customer retrials commonly occur in many service systems, such as healthcare, call centers, mobile networks, computer systems, and inventory systems. However, because of their complex nature, retrial queues are often more difficult to analyze than queues without retrials. In “Reducing Delay in Retrial Queues by Simultaneously Differentiating Service and Retrial Rates”, J. Wang, Z. Wang, and Y. Liu develop a service grade differentiation policy for queueing models with customer retrials. They show that the average waiting time can be reduced through strategically allocating the rates of service and retrial times without needing additional service capacity. Counter to the intuition that higher service variability usually yields a larger delay, the authors show that the benefits of this simultaneous service-and-retrial differentiation (SSRD) policy outweigh the impact of the increased service variability. To validate the effectiveness of the new SSRD policy, the authors provide (i) conditions under which SSRD is more beneficial, (ii) closed-form expressions of the optimal policy, (iii) asymptotic reduction of customer delays when the system is in heavy traffic, and (iv) insightful observations/discussions and numerical results.

scholarly journals Improving Drought Tolerance in Mungbean (Vigna radiata L. Wilczek): Morpho-Physiological, Biochemical and Molecular Perspectives

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1534
Author(s):  
Chandra Mohan Singh ◽  
Poornima Singh ◽  
Chandrakant Tiwari ◽  
Shalini Purwar ◽  
Mukul Kumar ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Crop Production ◽  
Mitigation Strategies ◽  
Theoretical Research ◽  
Whole Genome Sequence ◽  
Complex Nature ◽  
Drought Tolerant ◽  
Breeding Programmes ◽  
The Impact

Drought stress is considered a severe threat to crop production. It adversely affects the morpho-physiological, biochemical and molecular functions of the plants, especially in short duration crops like mungbean. In the past few decades, significant progress has been made towards enhancing climate resilience in legumes through classical and next-generation breeding coupled with omics approaches. Various defence mechanisms have been reported as key players in crop adaptation to drought stress. Many researchers have identified potential donors, QTLs/genes and candidate genes associated to drought tolerance-related traits. However, cloning and exploitation of these loci/gene(s) in breeding programmes are still limited. To bridge the gap between theoretical research and practical breeding, we need to reveal the omics-assisted genetic variations associated with drought tolerance in mungbean to tackle this stress. Furthermore, the use of wild relatives in breeding programmes for drought tolerance is also limited and needs to be focused. Even after six years of decoding the whole genome sequence of mungbean, the genome-wide characterization and expression of various gene families and transcriptional factors are still lacking. Due to the complex nature of drought tolerance, it also requires integrating high throughput multi-omics approaches to increase breeding efficiency and genomic selection for rapid genetic gains to develop drought-tolerant mungbean cultivars. This review highlights the impact of drought stress on mungbean and mitigation strategies for breeding high-yielding drought-tolerant mungbean varieties through classical and modern omics technologies.

Type A aortic dissection: involvement of carotid artery and impact on cerebral malperfusion

2020 ◽  
pp. 021849232098432
Author(s):  
Wahaj Munir ◽  
Jun Heng Chong ◽  
Amer Harky ◽  
Mohamad Bashir ◽  
Benjamin Adams
Keyword(s):  
Carotid Artery ◽  
Aortic Dissection ◽  
Type A ◽  
Current Evidence ◽  
Management Approach ◽  
Complex Nature ◽  
Acute Type ◽  
Type A Aortic Dissection ◽  
Cerebral Malperfusion ◽  
The Impact

Acute type A aortic dissection is a surgical emergency and management of such pathology can be complex with poor outcomes when there is organ malperfusion. Carotid artery involvement is present in 30% of patients diagnosed with acute type A aortic dissection, and given its emergency and complex nature, there is much controversy regarding the approach, extent of treatment, and timing of the intervention. It is clear that the occurrence of cerebral malperfusion adds an extra layer of complexity to the decision-making framework for treatment. Standardization and validation of the optimal management approach is required, and this should ideally be addressed with large-scale studies. Nonetheless, current literature supports the need for rapid recognition and diagnosis of acute type A aortic dissection with cerebral malperfusion, immediate and extensive surgical repair, and the appropriate use of cerebral perfusion techniques. This paper aims to discuss the current evidence regarding the impact of carotid artery involvement in both the management and outcomes of acute type A aortic dissection.

scholarly journals The Science of Ageism: Two Steps Forward, One Step Back

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 646-646
Author(s):  
Jerin Lee ◽  
Natalie Shook
Keyword(s):  
Psychological Health ◽  
Well Being ◽  
Census Bureau ◽  
Complex Nature ◽  
The Past ◽  
Growing Pains ◽  
Research Findings ◽  
One Step ◽  
Prejudicial Attitudes ◽  
The Impact

Abstract The past two decades have been marked by a rapidly aging population in the U.S. (U.S. Census Bureau, 2018), making prejudicial attitudes toward older adults (i.e., ageism) and the impact of such attitudes more relevant. As such, ageism researchers have worked tirelessly to not only understand this normalized and insidious form of bias, but also develop efforts to combat it. This symposium will feature four ageism researchers who will showcase both the growing pains and novel contributions of ageism research, ranging from the impact of ageism on psychological health to ageism interventions to issues related to the measurement of ageism. Specifically, Dr. Ayalon will present findings regarding difficulties with the assessment of exposure to ageism and the consequences of ageism for psychological well-being. Dr. Horhota will share research demonstrating challenges associated with confronting ageism. Dr. Levy will present a model showcasing factors associated with the reduction of ageism. Ms. Lee will discuss research findings examining the construct validity of several ageism measures. These talks highlight theoretical and real-world implications associated with the complex nature of ageism, providing important directions for enriching ageism research going forward.

scholarly journals The Impact of Probability Density Functions Assessment on Model Performance for Slope Stability Analysis

Geosciences ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 322
Author(s):  
Evelina Volpe ◽  
Luca Ciabatta ◽  
Diana Salciarini ◽  
Stefania Camici ◽  
Elisabetta Cattoni ◽  
...  
Keyword(s):  
Probability Density ◽  
Central Italy ◽  
Model Performance ◽  
Probability Density Functions ◽  
Slope Instability ◽  
Complex Nature ◽  
Density Functions ◽  
Umbria Region ◽  
Input Variables ◽  
The Impact

The development of forecasting models for the evaluation of potential slope instability after rainfall events represents an important issue for the scientific community. This topic has received considerable impetus due to the climate change effect on territories, as several studies demonstrate that an increase in global warming can significantly influence the landslide activity and stability conditions of natural and artificial slopes. A consolidated approach in evaluating rainfall-induced landslide hazard is based on the integration of rainfall forecasts and physically based (PB) predictive models through deterministic laws. However, considering the complex nature of the processes and the high variability of the random quantities involved, probabilistic approaches are recommended in order to obtain reliable predictions. A crucial aspect of the stochastic approach is represented by the definition of appropriate probability density functions (pdfs) to model the uncertainty of the input variables as this may have an important effect on the evaluation of the probability of failure (PoF). The role of the pdf definition on reliability analysis is discussed through a comparison of PoF maps generated using Monte Carlo (MC) simulations performed over a study area located in the Umbria region of central Italy. The study revealed that the use of uniform pdfs for the random input variables, often considered when a detailed geotechnical characterization for the soil is not available, could be inappropriate.

scholarly journals The Correlation between Physical Crosslinking and Water-Soluble Drug Release from Chitosan-Based Microparticles

Pharmaceutics ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 455
Author(s):  
Emilia Szymańska ◽  
Katarzyna Woś-Latosi ◽  
Julia Jacyna ◽  
Magdalena Dąbrowska ◽  
Joanna Potaś ◽  
...  
Keyword(s):  
Drug Release ◽  
Polymer Matrix ◽  
Drug Loading ◽  
Water Soluble ◽  
Dissolution Behavior ◽  
Complex Nature ◽  
Prolonged Release ◽  
Scanning Calorimetry ◽  
Burst Effect ◽  
The Impact

Microparticles containing water-soluble zidovudine were prepared by spray-drying using chitosan glutamate and beta-glycerophosphate as an ion crosslinker (CF). The Box–Behnken design was applied to optimize the microparticles in terms of their drug loading and release behavior. Physicochemical studies were undertaken to support the results from dissolution tests and to evaluate the impact of the crosslinking ratio on the microparticles’ characteristics. The zidovudine dissolution behavior had a complex nature which comprised two phases: an initial burst effect followed with a prolonged release stage. The initial drug release, which can be modulated by the crosslinking degree, was primarily governed by the dissolution of the drug crystals located on the microparticles’ surfaces. In turn, the further dissolution stage was related to the drug diffusion from the swollen polymer matrix and was found to correlate with the drug loading. Differential Scanning Calorimetry (DSC) studies revealed the partial incorporation of a non-crystallized drug within the polymer matrix, which correlated with the amount of CF. Although CF influenced the swelling capacity of chitosan glutamate microparticles, surprisingly a higher amount of CF did not impact the time required for 80% of the drug to be released markedly. The formulation with the lowest polymer:CF ratio, 3:1, was selected as optimal, providing satisfactory drug loading and displaying a moderate burst effect within the first 30 min of the study, followed with a prolonged drug release of up to 210 min.

scholarly journals Measuring Key Quality Indicators in Cloud Gaming: Framework and Assessment Over Wireless Networks

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1387
Author(s):  
Oswaldo Sebastian Peñaherrera-Pulla ◽  
Carlos Baena ◽  
Sergio Fortes ◽  
Eduardo Baena ◽  
Raquel Barco
Keyword(s):  
Communication Networks ◽  
Mobile Networks ◽  
Video Game ◽  
Know How ◽  
Fifth Generation ◽  
New Generation ◽  
Graphics Rendering ◽  
The Impact

Cloud Gaming is a cutting-edge paradigm in the video game provision where the graphics rendering and logic are computed in the cloud. This allows a user’s thin client systems with much more limited capabilities to offer a comparable experience with traditional local and online gaming but using reduced hardware requirements. In contrast, this approach stresses the communication networks between the client and the cloud. In this context, it is necessary to know how to configure the network in order to provide service with the best quality. To that end, the present work defines a novel framework for Cloud Gaming performance evaluation. This system is implemented in a real testbed and evaluates the Cloud Gaming approach for different transport networks (Ethernet, WiFi, and LTE (Long Term Evolution)) and scenarios, automating the acquisition of the gaming metrics. From this, the impact on the overall gaming experience is analyzed identifying the main parameters involved in its performance. Hence, the future lines for Cloud Gaming QoE-based (Quality of Experience) optimization are established, this way being of configuration, a trendy paradigm in the new-generation networks, such as 4G and 5G (Fourth and Fifth Generation of Mobile Networks).

scholarly journals Analytical Model for Estimating the Impact of Changing the Nominal Power Parameter in LTE

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
A. B. Vallejo-Mora ◽  
M. Toril ◽  
S. Luna-Ramírez ◽  
M. Regueira ◽  
S. Pedraza
Keyword(s):  
Analytical Model ◽  
Mobile Networks ◽  
Radio Resource Management ◽  
Estimation Accuracy ◽  
Model Assessment ◽  
Power Parameter ◽  
Management Procedure ◽  
Proposed Model ◽  
A Cell ◽  
The Impact

UpLink Power Control (ULPC) is a key radio resource management procedure in mobile networks. In this paper, an analytical model for estimating the impact of increasing the nominal power parameter in the ULPC algorithm for the Physical Uplink Shared CHannel (PUSCH) in Long Term Evolution (LTE) is presented. The aim of the model is to predict the effect of changing the nominal power parameter in a cell on the interference and Signal-to-Interference-plus-Noise Ratio (SINR) of that cell and its neighbors from network statistics. Model assessment is carried out by means of a field trial where the nominal power parameter is increased in some cells of a live LTE network. Results show that the proposed model achieves reasonable estimation accuracy, provided uplink traffic does not change significantly.

scholarly journals Implementation of the No Poverty Sustainable Development Goal (SDG) in Visegrad Group (V4)

2021 ◽  
Vol 13 (3) ◽  
pp. 1030
Author(s):  
Elżbieta Sobczak ◽  
Bartosz Bartniczak ◽  
Andrzej Raszkowski
Keyword(s):  
Sustainable Development ◽  
Socioeconomic Development ◽  
Complex Nature ◽  
Sustainable Development Goal ◽  
Development Goal ◽  
Poverty Area ◽  
Development Level ◽  
Poverty Indicators ◽  
The Impact ◽  
Visegrad Group

This presented study discusses problems related to the implementation of the Sustainable Development Goal 1: No Poverty, aimed at eliminating poverty, based on the example of the Visegrad Group (V4) countries. The introduction addresses the general characteristics of the V4 and attempts to define the concept of sustainable development, with particular emphasis on its complex nature and importance for future generations. The purpose of the research was to assess the diversity within the Visegrad Group countries in the years 2005–2018 in terms of poverty and sustainable development level in the No Poverty area and also to identify the impact of the socioeconomic development level in the studied countries on sustainable development in the No Poverty area. Taking into account the analysis of poverty indicators in the Visegrad Group countries, the best results were recorded for Czechia. The second part of the conducted analyzed allowed us to conclude that Czechia definitely presents the highest level of sustainable development, followed by Slovakia. The highest average dynamics of changes occur in Poland and Hungary, which result in the gradual elimination of the existing disproportions. Among other research results, it is worth highlighting that the V4 countries show significant, however, decreasing differences regarding the indicators describing poverty in relation to sustainable development.

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