4,458 research outputs found
Challenges and complexities in application of LCA approaches in the case of ICT for a sustainable future
In this work, three of many ICT-specific challenges of LCA are discussed.
First, the inconsistency versus uncertainty is reviewed with regard to the
meta-technological nature of ICT. As an example, the semiconductor technologies
are used to highlight the complexities especially with respect to energy and
water consumption. The need for specific representations and metric to
separately assess products and technologies is discussed. It is highlighted
that applying product-oriented approaches would result in abandoning or
disfavoring of new technologies that could otherwise help toward a better
world. Second, several believed-untouchable hot spots are highlighted to
emphasize on their importance and footprint. The list includes, but not limited
to, i) User Computer-Interfaces (UCIs), especially screens and displays, ii)
Network-Computer Interlaces (NCIs), such as electronic and optical ports, and
iii) electricity power interfaces. In addition, considering cross-regional
social and economic impacts, and also taking into account the marketing nature
of the need for many ICT's product and services in both forms of hardware and
software, the complexity of End of Life (EoL) stage of ICT products,
technologies, and services is explored. Finally, the impact of smart management
and intelligence, and in general software, in ICT solutions and products is
highlighted. In particular, it is observed that, even using the same
technology, the significance of software could be highly variable depending on
the level of intelligence and awareness deployed. With examples from an
interconnected network of data centers managed using Dynamic Voltage and
Frequency Scaling (DVFS) technology and smart cooling systems, it is shown that
the unadjusted assessments could be highly uncertain, and even inconsistent, in
calculating the management component's significance on the ICT impacts.Comment: 10 pages. Preprint/Accepted of a paper submitted to the ICT4S
Conferenc
Objective assessment of region of interest-aware adaptive multimedia streaming quality
Adaptive multimedia streaming relies on controlled
adjustment of content bitrate and consequent video quality variation in order to meet the bandwidth constraints of the communication
link used for content delivery to the end-user. The values of the easy to measure network-related Quality of Service metrics have no direct relationship with the way moving images are
perceived by the human viewer. Consequently variations in the video stream bitrate are not clearly linked to similar variation in the user perceived quality. This is especially true if some human visual system-based adaptation techniques are employed. As research has shown, there are certain image regions in each frame of a video sequence on which the users are more interested than in the others. This paper presents the Region of Interest-based Adaptive Scheme (ROIAS) which adjusts differently the regions within each frame of the streamed multimedia content based on the user interest in them. ROIAS is presented and discussed in terms of the adjustment algorithms employed and their impact on the human perceived video quality. Comparisons with existing approaches, including a constant quality adaptation scheme across the whole frame area, are performed employing two objective metrics which estimate user perceived video quality
Research and Education in Computational Science and Engineering
Over the past two decades the field of computational science and engineering
(CSE) has penetrated both basic and applied research in academia, industry, and
laboratories to advance discovery, optimize systems, support decision-makers,
and educate the scientific and engineering workforce. Informed by centuries of
theory and experiment, CSE performs computational experiments to answer
questions that neither theory nor experiment alone is equipped to answer. CSE
provides scientists and engineers of all persuasions with algorithmic
inventions and software systems that transcend disciplines and scales. Carried
on a wave of digital technology, CSE brings the power of parallelism to bear on
troves of data. Mathematics-based advanced computing has become a prevalent
means of discovery and innovation in essentially all areas of science,
engineering, technology, and society; and the CSE community is at the core of
this transformation. However, a combination of disruptive
developments---including the architectural complexity of extreme-scale
computing, the data revolution that engulfs the planet, and the specialization
required to follow the applications to new frontiers---is redefining the scope
and reach of the CSE endeavor. This report describes the rapid expansion of CSE
and the challenges to sustaining its bold advances. The report also presents
strategies and directions for CSE research and education for the next decade.Comment: Major revision, to appear in SIAM Revie
Sub-GHz LPWAN network coexistence, management and virtualization : an overview and open research challenges
The IoT domain is characterized by many applications that require low-bandwidth communications over a long range, at a low cost and at low power. Low power wide area networks (LPWANs) fulfill these requirements by using sub-GHz radio frequencies (typically 433 or 868 MHz) with typical transmission ranges in the order of 1 up to 50 km. As a result, a single base station can cover large areas and can support high numbers of connected devices (> 1000 per base station). Notorious initiatives in this domain are LoRa, Sigfox and the upcoming IEEE 802.11ah (or "HaLow") standard. Although these new technologies have the potential to significantly impact many IoT deployments, the current market is very fragmented and many challenges exists related to deployment, scalability, management and coexistence aspects, making adoption of these technologies difficult for many companies. To remedy this, this paper proposes a conceptual framework to improve the performance of LPWAN networks through in-network optimization, cross-technology coexistence and cooperation and virtualization of management functions. In addition, the paper gives an overview of state of the art solutions and identifies open challenges for each of these aspects
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