Holistic Measures for Evaluating Prediction Models in Smart Grids

The performance of prediction models is often based on "abstract metrics" that estimate the model's ability to limit residual errors between the observed and predicted values. However, meaningful evaluation and selection of prediction models for end-user domains requires holistic and application-sensitive performance measures. Inspired by energy consumption prediction models used in the emerging "big data" domain of Smart Power Grids, we propose a suite of performance measures to rationally compare models along the dimensions of scale independence, reliability, volatility and cost. We include both application independent and dependent measures, the latter parameterized to allow customization by domain experts to fit their scenario. While our measures are generalizable to other domains, we offer an empirical analysis using real energy use data for three Smart Grid applications: planning, customer education and demand response, which are relevant for energy sustainability. Our results underscore the value of the proposed measures to offer a deeper insight into models' behavior and their impact on real applications, which benefit both data mining researchers and practitioners.Comment: 14 Pages, 8 figures, Accepted and to appear in IEEE Transactions on Knowledge and Data Engineering, 2014. Authors' final version. Copyright transferred to IEE

Methodologies for Assessment of Building's Energy Efficiency and Conservation: A Policy-Maker View

Recent global peer-review reports have concluded on importance of buildings in tacking the energy security and climate change challenges. To integrate the buildings energy efficiency into the policy agenda, significant research efforts have been recently done. More specifically, the public domain provides a bulk of literature on the application of buildings-related efficiency technologies and behavioural patterns, barriers to penetration of these practices, policies to overcome these barriers. From the policy-making perspective it is useful to understand how far our understanding of building energy efficiency goes and the approaches and methodologies are behind such assessment.Buildings, energy efficiency potential, greenhouse gas mitigation, policy assessment, energy policy impact evaluation, sectoral efficiency targets

Total energy-rate feedback for automatic glide-slope tracking during wind-shear penetration

Low-altitude wind shear is recognized as an infrequent but significant hazard to all aircraft during the take-off and landing phases of flight. A total energy-rate sensor was developed for measuring the specific total energy rate of an airplane with respect to the air mass. Control-system designs, both with and without energy-rate feedback, for the approach to landing of a transport airplane through a severe-wind-shear and gust environment are presented in order to evaluate this application of the sensor. A system model incorporates wind-shear-dynamics equations with the airplane equations of motion to permit analysis of the control systems under various wind-shear conditions. The control systems are designed using optimal-output feedback and are analyzed using frequency-domain control-theory techniques. Control-system performance is evaluated using a complete nonlinear simulation of the airplane combined with a severe-wind-shear and gust data package. This evaluation is concerned with control system stability and regulation capability only

Application Performance of Physical System Simulations

Various parallel computer benchmarking projects have been around since early 1990s but the adopted so far approaches for performance analysis require a significant revision in view of the recent developments of both the application domain and the computer technologies. This paper presents a novel performance evaluation methodology based on assessing the processing rate of two orthogonal use cases – dense and sparse physical systems – as well as the energy efficiency for both. Evaluation results with two popular codes — HPL and HPCG — validate our approach and demonstrate its use for analysis and interpretation in order to identify and confirm current technological challenges as well as to track and roadmap the future application performance of physical system simulations

Evaluating the Transition Towards Post-Carbon Cities: A Literature Review

To achieve the new European targets concerning CO2 emission reduction, the concept of a post-carbon city has been promoted, which is focused on low-energy and low-emission buildings provided with intelligent heating and cooling systems, electric and hybrid cars, and better public transport. This paradigm entails the inclusion of aspects not strictly related to energy exploitation but referring to environmental, social, and economic domains, such as improvement in local energy security, people’s opinion on different energy solutions, economic co-benefits for private users, environmental externalities, and so on. In this domain, it is of particular importance to provide the decision makers with evaluation tools able to consider the complexity of the impacts, thus leading to the choice of the most sustainable solutions. The paper aims to investigate the scientific literature in the context of evaluation frameworks for supporting decision problems related to the energy transition. The review is carried out through the scientific database SCOPUS. The analysis allows for systematizing the contributions according to the main families of evaluation methodologies, discussing to what extent they can be useful in real-world applications. The paper also proposes emerging trends and innovative research lines in the domain of energy planning and urban management. While the energy transition is an important trend, the analysis showed that few studies were conducted on the evaluation of projects, plans, and policies that aim to reach post-carbon targets. The scales of application refer mainly to global or national levels, while few studies have been developed at the district level. Life cycle thinking techniques, such as life cycle assessment and cost-benefit analysis, were widely used in this research field

A model evaluation protocol for Computational Fluid Dynamics (CFD) models used in safety analyses for hydrogen and fuel cell technologies

Hydrogen and fuel cell technologies are seen as an increasingly important means of energy conversion and energy storage as European energy policies encourage transition to renewable sources, reduction of greenhouse gas emissions, and an increase in energy efficiency. This brings a corresponding move of these technologies out of the industrial domain, which is characterised by large quantities and a controlled environment, to the public domain which is characterised by a more diverse range of applications in typically less well controlled environments. The increase in demand brings an increasing need to carry out safety analyses and will therefore result in a more widespread deployment of modern numerical tools such as Computational Fluid Dynamics (CFD). This in turn has led to a requirement for a better understanding of the suitability of CFD models for each specific application. Model Evaluation Protocols have been in existence for many years as a means of testing the quality of simulation tools mainly in the area of pollutant dispersion modelling. There have been several European initiatives for model evaluation covering dispersion, as well as fire and explosion modelling. The “SUpport to SAfety ANalysis of Hydrogen and Fuel Cell Technologies” (SUSANA) project aims to support stakeholders using CFD for safety engineering design and assessment of fuel cells and hydrogen (FCH) systems and infrastructure through the development of a new model evaluation protocol. The protocol covers all aspects of safety assessment modelling using CFD, from release, through dispersion to combustion and not only aims to enable users to evaluate models but to inform them of the state of the art and best practices in numerical modelling. To achieve the aims, the project has seven work packages which are based upon a support strategy of collecting information from outside the project and disseminating this information to the user community. There are seven partners in the SUSANA consortium and each is responsible for a particular work package and coordinating the work of the other partners in that area. This paper gives an overview of the SUSANA project, the work packages and the main stages of the model evaluation protocol.JRC.F.2-Energy Conversion and Storage Technologie

Development of an oceanographic application in HPC

High Performance Computing (HPC) is used for running advanced application programs efficiently, reliably, and quickly. In earlier decades, performance analysis of HPC applications was evaluated based on speed, scalability of threads, memory hierarchy. Now, it is essential to consider the energy or the power consumed by the system while executing an application. In fact, the High Power Consumption (HPC) is one of biggest problems for the High Performance Computing (HPC) community and one of the major obstacles for exascale systems design. The new generations of HPC systems intend to achieve exaflop performances and will demand even more energy to processing and cooling. Nowadays, the growth of HPC systems is limited by energy issues Recently, many research centers have focused the attention on doing an automatic tuning of HPC applications which require a wide study of HPC applications in terms of power efficiency. In this context, this paper aims to propose the study of an oceanographic application, named OceanVar, that implements Domain Decomposition based 4D Variational model (DD-4DVar), one of the most commonly used HPC applications, going to evaluate not only the classic aspects of performance but also aspects related to power efficiency in different case of studies. These work were realized at Bsc (Barcelona Supercomputing Center), Spain within the Mont-Blanc project, performing the test first on HCA server with Intel technology and then on a mini-cluster Thunder with ARM technology. In this work of thesis it was initially explained the concept of assimilation date, the context in which it is developed, and a brief description of the mathematical model 4DVAR. After this problem’s close examination, it was performed a porting from Matlab description of the problem of data-assimilation to its sequential version in C language. Secondly, after identifying the most onerous computational kernels in order of time, it has been developed a parallel version of the application with a parallel multiprocessor programming style, using the MPI (Message Passing Interface) protocol. The experiments results, in terms of performance, have shown that, in the case of running on HCA server, an Intel architecture, values of efficiency of the two most onerous functions obtained, growing the number of process, are approximately equal to 80%. In the case of running on ARM architecture, specifically on Thunder mini-cluster, instead, the trend obtained is labeled as "SuperLinear Speedup" and, in our case, it can be explained by a more efficient use of resources (cache memory access) compared with the sequential case. In the second part of this paper was presented an analysis of the some issues of this application that has impact in the energy efficiency. After a brief discussion about the energy consumption characteristics of the Thunder chip in technological landscape, through the use of a power consumption detector, the Yokogawa Power Meter, values of energy consumption of mini-cluster Thunder were evaluated in order to determine an overview on the power-to-solution of this application to use as the basic standard for successive analysis with other parallel styles. Finally, a comprehensive performance evaluation, targeted to estimate the goodness of MPI parallelization, is conducted using a suitable performance tool named Paraver, developed by BSC. Paraver is such a performance analysis and visualisation tool which can be used to analyse MPI, threaded or mixed mode programmes and represents the key to perform a parallel profiling and to optimise the code for High Performance Computing. A set of graphical representation of these statistics make it easy for a developer to identify performance problems. Some of the problems that can be easily identified are load imbalanced decompositions, excessive communication overheads and poor average floating operations per second achieved. Paraver can also report statistics based on hardware counters, which are provided by the underlying hardware. This project aimed to use Paraver configuration files to allow certain metrics to be analysed for this application. To explain in some way the performance trend obtained in the case of analysis on the mini-cluster Thunder, the tracks were extracted from various case of studies and the results achieved is what expected, that is a drastic drop of cache misses by the case ppn (process per node) = 1 to case ppn = 16. This in some way explains a more efficient use of cluster resources with an increase of the number of processes

Comparative performance of isolated and fixed-base reinforced concrete structures

The earthquake transmits to the structure a large quantity of energy that causes damage to structures. The seismic isolation technique can absorb a large quantity of the seismic energy. The seismic isolation concept is a new technique in earthquake engineering, its principle is quite simple, and it consists to create a discontinuity between the foundation and the superstructure, so that seismic energy cannot be completely transmitted into the structure.Therefore, this article includes a numerical application of the nonlinear static method, the capacity spectrum method (CSM), on two types of structures, fixed base structure and isolated base structure. The CSM is one of the methods used for the evaluation of seismic performance. Its principle consists in superimposing a curve which represents the capacity of the structure originated from a non-linear static analysis (Pushover), with a curve representing the solicitation brought by the earthquake. The intersection of these two curves represents the point performance, which evaluates the maximum displacement of the structure in the plastic domain