A heuristic approach for provider selection and task allocation model in telecommunication networks under stochastic QOS guaranties

In this study, we model provider selection and task allocation problem as an expected cost minimization problem with stochastic chance constraints. Two important parameters of Quality of Service (QoS), delay and jitter are considered as random variables to capture stochastic nature of telecom network environment. As solution methodology, stochastic model is converted into its deterministic equivalent and then a novel heuristic algorithm is proposed to solve resulting nonlinear mixed integer programming model. Finally, performance of solution procedure is tested by several randomly generated scenarios

The effects of qos level degradation cost on provider selection and task allocation model in telecommunication networks

Firms acquire network capacity from multiple suppliers which offer different Quality of Service (QoS) levels. After acquisition, day-to-day operations such as video conferencing, voice over IP and data applications are allocated between these acquired capacities by considering QoS requirement of each operation. In optimal allocation scheme, it is generally assumed each operation has to be placed into resource that provides equal or higher QoS Level. Conversely, in this study it is showed that former allocation strategy may lead to suboptimal solutions depending upon penalty cost policy to charge degradation in QoS requirements. We model a cost minimization problem which includes three cost components namely capacity acquisition, opportunity and penalty due to loss in QoS

Production of upgraded metallurgical-grade silicon for a low-cost, high-efficiency, and reliable PV technology

Upgraded metallurgical-grade silicon (UMG-Si) has the potential to reduce the cost of photovoltaic (PV) technology and improve its environmental profile. In this contribution, we summarize the extensive work made in the research and development of UMG technology for PV, which has led to the demonstration of UMG-Si as a competitive alternative to polysilicon for the production of high-efficiency multicrystalline solar cells and modules. The tailoring of the processing steps along the complete Ferrosolar’s UMG-Si manufacturing value chain is addressed, commencing with the purification stage that results in a moderately compensated material due to the presence of phosphorous and boron. Gallium is added as a dopant at the crystallization stage to obtain a uniform resistivity profile of ∼1 Ω cm along the ingot height. Defect engineering techniques based on phosphorus diffusion gettering are optimized to improve the bulk electronic quality of UMG-Si wafers. Black silicon texturing, compatible with subsequent gettering and surface passivation, is successfully implemented. Industrial-type aluminum back surface field (Al-BSF) and passivated emitter and rear cell (PERC) solar cells are fabricated, achieving cell efficiencies in the range of those obtained with conventional polysilicon substrates. TOPCon solar cell processing key steps are also tested to further evaluate the potential of the material in advanced device architectures beyond the PERC. Degradation mechanisms related to light exposure and operation temperature are shown to be insignificant in UMG PERC solar cells when a regeneration step is implemented, and PV modules with several years of outdoor operation demonstrated similar performance to reference ones based on poly-Si. Life cycle analysis (LCA) is carried out to evaluate the environmental impact of UMG-based PV technology when compared to poly-Si-based technology, considering different scenarios for both the manufacturing sites and the PV installations

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Stochastic fuzzy multi-objective backbone selection and capacity allocation problem under tax-band pricing policy with different fuzzy operators

In this paper, we investigate a multi-objective optimization problem that a telecom bandwidth broker (BB) faces when acquiring and selling bandwidth in an uncertain market environment in which there exists several backbone providers (BPs) and end users. The proposed model incorporates two important goals: maximizing expected profit and minimizing expected loss capacity within realistic constraints such as BPs' capacity, meeting the end users' bandwidth requests and satisfying the Quality of Service requests of end users', considering stochastic capacity loss rates of BPs. The fuzzy set theory and stochastic programming techniques are employed to handle the non-deterministic nature of telecommunication network setting due to the presence of vagueness and randomness of information. The model is formulated in such a way that it simultaneously considers the randomness in demand and determines the allocation of end users' bandwidth requests into purchased capacity based on tax-band pricing scheme. As solution strategies, two different fuzzy operators, namely max-min and weighted additive max-min, are integrated into a resulting two-stage multi-objective stochastic linear programming model. Then, algorithms are provided to solve and to compare methodologies with deterministic approaches. Finally, the proposed algorithms are tested on several randomly generated test scenarios to provide managerial insight to decision makers of BB companies. , Springer-Verlag Berlin Heidelberg.Scopu

A research on the effect of social media from digital marketing tools on hedonic consumption behaviors

Günümüzde artan sosyal medya kullanımı nedeniyle işletmeler de pazarlama kampanyalarında bazı yeni stratejiler uygulamaya başlamıştır. Sosyal ağ kullanım oranının artmasıyla birlikte, dijital platformlarda yapılan satın alımlar da önemli ölçüde artış görülmüştür. Bu nedenle sosyal ağlarda ve dijital platformlarda karşılaşılan içerikler tüketicilerin satın alma davranışlarını etkilemektedir. Bu çalışmanın amacı; dijital pazarlama araçlarından olan sosyal medya pazarlamasının hazcı tüketim üzerinde etkisinin olup olmadığını belirlemektir. Kolayda örnekleme yöntemiyle online anket uygulayarak Gaziantep'te bulunan 400 kişiye uygulanmıştır. Ulaşılan veriler SPSS ve AMOS paket programlarıyla analiz yapılarak yorumlanmıştır. Analizler sonucunda değişkenler arasında anlamlı ilişkiler bulunmuştur. Bu çalışma kapsamında; dijital pazarlama araçlarından olan sosyal medya pazarlaması hazcı tüketimi etkilediği tespit edilmiştir.Due to the increasing use of social media today, businesses have started to implement some new strategies in their marketing campaigns. With the increase in the use of social networks, purchases made on digital platforms have also increased significantly. For this reason, the contents encountered in social networks and digital platforms affect the purchasing behavior of consumers. The aim of this study; To determine whether social media marketing, which is one of the digital marketing tools, has an effect on hedonistic consumption. It was applied to 400 people in Gaziantep by applying an online survey with easy sampling method. The obtained data were interpreted by analyzing with SPSS and AMOS package programs. As a result of the analyzes, significant relationships were found between the variables. This scope of work; It has been determined that social media marketing, which is one of the digital marketing tools, affects hedonistic consumption

Provider selection and task allocation problems under fuzzy QoS constraints and volume discount pricing policy for telecommunication network

Nowadays every firm uses telecommunication networks to continue their existence and complete their daily operations. In this paper, we investigate an optimization problem that a firm faces when acquiring network capacity from a market in which there exist several network providers offering different pricing and quality of service schemes. In the mathematical model, quality of service level guaranteed by network providers and minimum quality of service level which is needed to accomplishing operations are denoted as fuzzy numbers. Finally, a heuristic solution procedure is proposed to solve resulting nonlinear mixed integer programming model with fuzzy coefficients

A bandwidth sourcing and task allocation model in telecommunications under stochastic QoS guarantees

In this study, we model bandwidth provider selection and task allocation problem as an expected cost minimization problem with stochastic constraints. Two important parameters of quality of service (QoS), namely delay and jitter are considered as random variables to capture stochastic nature of telecom network environment. As solution methodology, stochastic model is converted into its deterministic equivalent and then a novel heuristic algorithm is proposed to solve resulting nonlinear mixed integer programming model. We analyze how different prices, quality and task distribution affect the optimal behavior of the firm. Finally, performance of solution procedure is tested by several randomly generated scenarios and by a relaxation of this problem as tight lower bound