2014
Autores
Ilie I.; Hernando-Gil I.; Djokic S.;
Publicação
International Journal of Electrical Power and Energy Systems
Abstract
Legislation defined to protect domestic and non-domestic customers from long durations of interruptions includes additional requirements to system's reliability-related performance that distribution network operators (DNOs) must consider in planning the operation and maintenance process of power supply systems. DNOs are required to restore the supply to interrupted customers that fall into "unprotected" customer class within a given period of time, otherwise penalties are applied. In order to meet these requirements, comprehensive strategies must be defined based on upfront analyses. Accordingly, this paper proposes a deterministic algorithm for estimating DNOs' risk of experiencing interruptions with durations above imposed targets. Besides the Regulator-defined legislation, security of supply requirements are engaged in the development of the proposed methodology. Failure analysis of network components is used to identify interrupted customers that are grouped into power demand classes such that the duration of interruptions can be addressed following the security of supply requirements. Moreover, the penalty times defined by the Energy Regulator are engaged in the analysis and used as thresholds to quantify the penalty risk that DNOs are exposed to. The proposed methodology is applied to a typical UK distribution system, whose average reliability performance is also considered in the analysis. © 2013 Elsevier Ltd. All rights reserved.
2014
Autores
Ziegler, J; Campos, JC; Nigay, L;
Publicação
ACM SIGCHI Symposium on Engineering Interactive Computing Systems, EICS'14, Rome, Italy, June 17-20, 2014
Abstract
This workshop intends to establish the basis of a roadmap addressing engineering challenges and emerging themes in HCI. Novel forms of interaction and new application domains involve aspects that are currently not sufficiently covered by existing methods and tools. The workshop will serve as a venue to bring together researchers and practitioners interested the Engineering of Human- Computer Interaction and in contributing to the definition of a roadmap for the field. The intention is to continue work on the roadmap in follow-up workshops as well as in the IFIP Working Group on User Interface Engineering. Copyright © 2014 ACM 978-1-4503-2725-1/14/06.
2014
Autores
Meira, D; Magalhães, L; Pereira, F; Peres, E;
Publicação
IJWP
Abstract
Despite being a recent phenomenon and being in constant evolution, e-commerce (EC) is already embedded in current society. However, difficulties in establishing a universally accepted definition have resulted in a multiplicity of meanings that sometimes merge with the e-business (EB) concept. This article presents a brief historical and conceptual evolution of EC and some of its most significant aspects. © 2018, IGI Global.
2014
Autores
Rocha, M; Oliveira, JF; Carravilla, MA;
Publicação
ANNALS OF OPERATIONS RESEARCH
Abstract
In this paper a constructive heuristic for solving the staff scheduling problem of a glass manufacture unit is proposed. Based on simple calculations and algorithms, the developed procedure assigns working shifts and days-off to teams of employees, ensuring the satisfaction of a mandatory sequence of working shifts and the balance of the workload between employees. The computational times for the experiments with the case study company, with three eight-hour working shifts and five teams of employees, fell consistently below 5 seconds for a set of different planning periods. Results are compared with the ones achieved with an optimization model (MIP), demonstrating the good performance of the heuristic, also in terms of the quality of the achieved solutions. The heuristic rarely fails to produce a feasible solution and whenever the solution is feasible then it is also optimal. When tackling problems with a large number of teams, the heuristic maintains the good performance while the MIP model is not able to find any solution within 16 hours of running time. Although it was designed for a particular problem of the glass industry, tests show that the heuristic is flexible enough to be applied to problems with different features, from other activity sectors, encouraging further extensions of this work.
2014
Autores
Tan, J; Drolia, U; Martins, R; Gandhi, R; Narasimhan, P;
Publicação
IEEE 6th International Conference on Cloud Computing Technology and Science, CloudCom 2014, Singapore, December 15-18, 2014
Abstract
The rapid growth in mobile devices will give rise to the trend of the leasing out of compute and data resources on mobile devices to third-parties for applications to be run on multiple mobile devices. However, these third-party applications running on leased mobile devices are typically written by unknown entities, and cannot be trusted by mobile device owners. Current mobile device platforms (e.g. Android) have permissions and access control systems designed for mobile apps that are written by reputable developers and vetted by authoritative app stores, and they are not suitable for untrusted apps. We propose STOVEPipe, an observable access control system for user data on mobile devices for untrusted third-party applications. STOVEPipe ensures that untrusted code is isolated and cannot directly access system data, and performs all data accesses on behalf of untrusted apps. This enables STOVEPipe to observe all data accessed by untrusted apps, implement content-based access control, perform accounting and auditing on accessed data easily, and perform privacy-preserving data transformations. © 2014 IEEE.
2014
Autores
Heydarian Forushani, E; Moghaddam, MP; Sheikh El Eslami, MK; Shafie khah, M; Catalao, JPS;
Publicação
IEEE TRANSACTIONS ON SUSTAINABLE ENERGY
Abstract
This paper proposes a comprehensive stochastic decision making model for wind power producers' (WPPs) participation in a competitive market. The presented model incorporates three trading floors: 1) day-ahead; 2) intraday; and 3) balancing markets. An efficient integration of intraday markets allows market players to react to the latest information (e. g., more accurate wind forecast). Creating a platform that allows demand response resources (DRRs) to contribute to the intraday markets improves both WPP's business and power system flexibility. In this context, providing an intraday demand response exchange (IDRX) market for trading demand response (DR) between DR providers and DR users (e. g., WPPs) is proposed. The problem uncertainties, such as wind power and market prices, are considered using a scenario-based approach. Moreover, an appropriate risk measurement, conditional value-at-risk (CVaR), is incorporated with the model. Numerical results illustrate that utilizing DR to compensate wind generation imbalances can increase WPP's profit and reduce the related risks.
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