41 research outputs found
Invited Abstract: Issues with State-based Energy Consumption Modelling
Energy consumption modelling by state based approaches often assume constant
energy consumption values in each state. However, it happens in certain
situations that during state transitions or even during a state the energy
consumption is not constant and does fluctuate. This paper discusses those
issues by presenting some examples from wireless sensor and wireless local area
networks for such cases and possible solutions.Comment: Published in: A. F\"orster, C. Minkenberg, G. R. Herrera, M. Kirsche
(Eds.), Proc. of the 2nd OMNeT++ Community Summit, IBM Research - Zurich,
Switzerland, September 3-4, 2015, arXiv:1509.03284, 201
The Internet of Things, fog and cloud continuum: Integration and challenges
The Internet of Things needs for computing power and storage are expected to remain on the rise in the next decade. Consequently, the amount of data generated by devices at the edge of the network will also grow. While cloud computing has been an established and effective way of acquiring computation and storage as a service to many applications, it may not be suitable to handle the myriad of data from IoT devices and fulfill largely heterogeneous application requirements. Fog computing has been developed to lie between IoT and the cloud, providing a hierarchy of computing power that can collect, aggregate, and process data from/to IoT devices. Combining fog and cloud may reduce data transfers and communication bottlenecks to the cloud and also contribute to reduced latencies, as fog computing resources exist closer to the edge. This paper examines this IoT-Fog-Cloud ecosystem and provides a literature review from different facets of it: how it can be organized, how management is being addressed, and how applications can benefit from it. Lastly, we present challenging issues yet to be addressed in IoT-Fog-Cloud infrastructures
Cost-effectiveness analysis of cinacalcet vs. paricalcitol in the treatment of hyperparathyroidism secondary to chronic kidney disease
ABSTRACT Introduction For the reduction of PTH levels, two classes of drugs are available in the Brazilian market: non-selective and selective vitamin D receptor activators and calcimimetics. Among the mentioned drugs, the SUS provides oral calcitriol, paricalcitol and cinacalcet. Objectives: Develop cost-effectiveness (CE) and budgetary impact (BI) analysis of cinacalcet versus paricalcitol for patients on dialysis with SHPT, from the perspective of SUS. Methodology: A decision tree model was constructed for CE analysis, which considered the outcome of avoided parathyroidectomy and a time horizon of 1 year. As for the BI analysis, two scenarios were considered, one of which was measured demand and other epidemiological, based on data from the Brazilian Society of Nephrology (BSN). Results: The CE analysis showed that the use of cinacalcet results in one-off savings of R 17,653.67 per avoided parathyroidectomy for cinacalcet, as it was more effective and cheaper compared to paricalcitol. As for the BI analysis, it was estimated that the incremental BI with the expansion of the use of cinacalcet in the SUS will be between - R 166,368.50 in the first year, considering the main and the epidemiological scenarios. At the end of 5 years after the expansion of use, an BI was estimated between - R 1,191,339.37; considering the same scenarios. Conclusion: Cinacalcet was dominant to avoid parathyroidectomies, being cost-effective
Experimental evaluation of multimedia services in WiMAX
WiMAX is a new technology that can provide long distance broadband wireless access based on IEEE 802.16 standards. After a short overview of IEEE 802.16 and the WiMAX network architecture, we center on the Quality of Service (QoS) support for multimedia applications in WiMAX. Inherent QoS support is an important factor differentiating WiMAX from other wireless access technologies, but so far has not been studied using off-the-shelf equipment. We fill this gap by empirically quantifying the performance of different multimedia applications and scheduling services in a WiMAX testbed. Specifically, the performance attained by multimedia applications over fixed WiMAX links, configured with Best Effort and Real Time Polling scheduling service classes is presented. We measure performance under both over-provisioned and under-provisioned configurations. When resources are substantially over-provisioned, the WiMAX equipment performs well and application requirements are fulfilled as expected. On the other hand, in under-provisioned conditions, applications using the Real Time Polling scheduling service enjoy better performance than those using the Best Effort scheduling service, but we note that proper configuration of the service flows may not be straightforward in practice
A Non-Intrusive Approach for Indoor Occupancy Detection in Smart Environments
Smart Environments try to adapt their conditions focusing on the detection, localisation, and identification of people to improve their comfort. It is common to use different sensors, actuators, and analytic techniques in this kind of environments to process data from the surroundings and actuate accordingly. In this research, a solution to improve the user’s experience in Smart Environments based on information obtained from indoor areas, following a non-intrusive approach, is proposed. We used Machine Learning techniques to determine occupants and estimate the number of persons in a specific indoor space. The solution proposed was tested in a real scenario using a prototype system, integrated by nodes and sensors, specifically designed and developed to gather the environmental data of interest. The results obtained demonstrate that with the developed system it is possible to obtain, process, and store environmental information. Additionally, the analysis performed over the gathered data using Machine Learning and pattern recognition mechanisms shows that it is possible to determine the occupancy of indoor environments
An IEEE 802.11 energy efficient mechanism for continuous media applications
The widespread deployment of wireless mobile communications enables an almost permanent usage of portable devices, which imposes high demands on the battery of these devices. Indeed, battery lifetime is becoming one the most critical factors on the end-users satisfaction when using wireless communications. In this work, the optimized power save algorithm for continuous media applications (OPAMA) is proposed, aiming at enhancing the energy efficiency on end-users devices. By combining the application specific requirements with data aggregation techniques, {OPAMA} improves the standard {IEEE} 802.11 legacy Power Save Mode (PSM) performance. The algorithm uses the feedback on the end-user expected quality to establish a proper tradeoff between energy consumption and application performance. {OPAMA} was assessed in the OMNeT++ simulator, using real traces of variable bitrate video streaming applications, and in a real testbed employing a novel methodology intended to perform an accurate evaluation concerning video Quality of Experience (QoE) perceived by the end-users. The results revealed the {OPAMA} capability to enhance energy efficiency without degrading the end-user observed QoE, achieving savings up to 44 when compared with the {IEEE} 802.11 legacy PSM