Toward sustainable data centers: a comprehensive energy management strategy

Data centers are major contributors to the emission of carbon dioxide to the atmosphere, and this contribution is expected to increase in the following years. This has encouraged the development of techniques to reduce the energy consumption and the environmental footprint of data centers. Whereas some of these techniques have succeeded to reduce the energy consumption of the hardware equipment of data centers (including IT, cooling, and power supply systems), we claim that sustainable data centers will be only possible if the problem is faced by means of a holistic approach that includes not only the aforementioned techniques but also intelligent and unifying solutions that enable a synergistic and energy-aware management of data centers. In this paper, we propose a comprehensive strategy to reduce the carbon footprint of data centers that uses the energy as a driver of their management procedures. In addition, we present a holistic management architecture for sustainable data centers that implements the aforementioned strategy, and we propose design guidelines to accomplish each step of the proposed strategy, referring to related achievements and enumerating the main challenges that must be still solved.Peer ReviewedPostprint (author's final draft

Performance assessment of open software platforms for 5G prototyping

Given the urgency of standardizing the fifth generation (5G) mobile systems to meet the ever more stringent demands of new applications, the importance of field trials and experimentation cannot be overstated. Practical experimentation with cellular networks has been historically reserved exclusively to operators, primarily due to equipment costs and licensing constraints. The state of play is changing with the advent of open source cellular stacks based on increasingly more affordable software defined radio (SDR) systems. However, comprehensive understanding of the performance, limitations, and interoperability of these tools is lacking. In this article we fill this gap by assessing, by means of controlled experiments, the performance of today's most popular open software eNB solutions in combination with different commodity UE and an SDR alternative, over a range of practical settings. Although these cannot underpin complete 5G systems yet, their development is progressing rapidly, and researchers have employed them for 5G-specific applications including LTE unlicensed and network slicing. We further shed light on the perils of open tools and give configuration guidelines that can be used to deploy these solutions effectively. Our results quantify the throughput attainable with each stack, their resource consumption footprint, and their reliability and bootstrap times in view of automating experimentation. Lastly, we qualitatively evaluate the extensibility of the solutions considered.The work of P. Serrano was partially supported by the European Commission in the framework of the H2020 5G-PPP 5G-MoNArch project (grant agreement no. 761445) and by the Madrid Regional Government through the TIGRE5-CM program (S2013/ICE-2919)

Towards a Service-Oriented Architecture for Production Planning and Control: A Comprehensive Review and Novel Approach

The trends of shorter product lifecycles, customized products, and volatile market environments require manufacturers to reconfigure their production increasingly frequent to maintain competitiveness and customer satisfaction. More frequent reconfigurations, however, are linked to increased efforts in production planning and control (PPC). This poses a challenge for manufacturers, especially in regard of demographic change and shortage of qualified labour, since many tasks in PPC are performed manually by domain experts. Following the paradigm of software-defined manufacturing, this paper targets to enable a higher degree of automation and interoperability in PPC by applying the concepts of service-oriented architecture. As a result, production planners are empowered to orchestrate tasks in PPC without consideration of underlying implementation details. At first, it is investigated how tasks in PPC can be represented as services with the aim of encapsulation and reusability. Secondly, a software architecture based on asset administration shells is presented that allows connection to production data sources and enables integration and usage of such PPC services. In this sense, an approach for mapping asset administrations shells to OpenAPI Specifications is proposed for interoperable and semantic integration of existing services and legacy systems. Lastly, challenges and potential solutions for data integration are discussed considering the present heterogeneity of data sources in manufacturing

Project Management Methodology for the Development of M-Learning Web Based Applications

M-learning web based applications are a particular case of web applications designed to be operated from mobile devices. Also, their purpose is to implement learning aspects. Project management of such applications takes into account the identified peculiarities. M-learning web based application characteristics are identified. M-learning functionality covers the needs of an educational process. Development is described taking into account the mobile web and its influences over the analysis, design, construction and testing phases. Activities building up a work breakdown structure for development of m-learning web based applications are presented. Project monitoring and control techniques are proposed. Resources required for projects are discussed.Software Project Management, M-Learning Applications, Web Applications, Methodology

Balancing labor requirements in a manufacturing environment

“This research examines construction environments within manufacturing facilities, specifically semiconductor manufacturing facilities, and develops a new optimization method that is scalable for large construction projects with multiple execution modes and resource constraints. The model is developed to represent real-world conditions in which project activities do not have a fixed, prespecified duration but rather a total amount of work that is directly impacted by the level of resources assigned. To expand on the concept of resource driven project durations, this research aims to mimic manufacturing construction environments by allowing a non-continuous resource allocation to project tasks. This concept allows for resources to shift between projects in order to achieve the optimal result for the project manager. Our model generates a novel multi-objective resource constrained project scheduling problem. Specifically, two objectives are studied; the minimization of the total direct labor cost and the minimization of the resource leveling. This research will utilize multiple techniques to achieve resource leveling and discuss the advantage each one provides to the project team, as well as a comparison of the Pareto Fronts between the given resource leveling and cost minimization objective functions. Finally, a heuristic is developed utilizing partial linear relaxation to scale the optimization model for large scale projects. The computation results from multiple randomly generated case studies show that the new heuristic method is capable of generating high quality solutions at significantly less computational time”--Abstract, page iv

On green routing and scheduling problem

The vehicle routing and scheduling problem has been studied with much interest within the last four decades. In this paper, some of the existing literature dealing with routing and scheduling problems with environmental issues is reviewed, and a description is provided of the problems that have been investigated and how they are treated using combinatorial optimization tools