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Publications

2015

Assessing low voltage network constraints in distributed energy resources planning

Authors
Calvillo, CF; Sanchez Miralles, A; Villar, J;

Publication
ENERGY

Abstract
Many efforts are being devoted towards achieving optimal planning and operation of DER (Distributed Energy Resources). However, during the planning process, not all relevant thermal constraints of the distribution network are considered; some works claim that they must be taken into account, while others follow the single-node approach. This paper assesses the effects of the distribution network thermal constraints in DER planning, using a deterministic linear programming problem to find the optimal DER planning and operation. Three case studies with different network topologies under several DER implementation scenarios are analyzed. A DC load flow is used to estimate the required network reinforcements to accommodate optimal DER investments, if any. Reinforcement costs are then calculated to assess the net benefit compared to limiting DER investments and operation, according to the network thermal limits. Results suggest that there is no significant economic advantage in limiting DER investments and line flows, compared to reinforcing the low voltage network to allow the larger flows that result from an unconstrained network problem.

2015

Waste identification diagrams

Authors
Dinis Carvalho, J; Moreira, F; Braganca, S; Costa, E; Alves, A; Sousa, R;

Publication
PRODUCTION PLANNING & CONTROL

Abstract
Value Stream Mapping (VSM) is a very popular tool in lean environments to represent production flows, mapping value stream of a product or family of products, and helps to identify some types of waste. Although very popular, this tool has some limitations as already described in many publications, especially in terms of restrictions in showing most types of waste as well as in its inability to represent various production routes. The purpose of this study is to introduce the waste identification diagram (WID), a new tool to represent production units with its different forms of waste, which overcomes some VSM limitations. The originality of WID comes from the use of its symbols' dimensions to convey, in a visual and immediate way, relevant information about a production unit. In this paper, WID is applied on a production unit of a lift manufacturer, for testing its performance and comparing it to VSM. The main findings are that WID is in general more effective than VSM in terms of representation of complex production units and in terms of identification of more forms of waste. WID must however overcome some of its limitations such as the lack of information-flow representation and the links to suppliers and clients.

2015

POPmine: Tracking Political Opinion on the Web

Authors
Saleiro, P; Amir, S; Silva, M; Soares, C;

Publication
CIT/IUCC/DASC/PICOM 2015 IEEE INTERNATIONAL CONFERENCE ON COMPUTER AND INFORMATION TECHNOLOGY - UBIQUITOUS COMPUTING AND COMMUNICATIONS - DEPENDABLE, AUTONOMIC AND SECURE COMPUTING - PERVASIVE INTELLIGENCE AND COMPUTING

Abstract
The automatic content analysis of mass media in the social sciences has become necessary and possible with the raise of social media and computational power. One particularly promising avenue of research concerns the use of opinion mining. We design and implement the POPmine system which is able to collect texts from web-based conventional media (news items in mainstream media sites) and social media (blogs and Twitter) and to process those texts, recognizing topics and political actors, analyzing relevant linguistic units, and generating indicators of both frequency of mention and polarity (positivity/negativity) of mentions to political actors across sources, types of sources, and across time.

2015

Influence of Large Renewable Energy Integration on Insular Grid Code Compliance

Authors
Rodrigues, EMG; Godina, R; Mendes, TDP; Matias, JCO; Catalao, JPS;

Publication
TECHNOLOGICAL INNOVATION FOR CLOUD-BASED ENGINEERING SYSTEMS

Abstract
Large-scale deployment of renewables in island energy systems attracts local attention of grid operators as a way of reducing fuel fossil consumption. Planning a grid based on renewable power plants poses serious challenges to the normal operation of a power system, namely on frequency and voltage stability. In past grid code compliance, wind turbines did not require services for supporting grid operation. To shift to large renewable energy integration, the island grid code should incorporate a new set of requirements in order to regulate the inclusion of these services, which is the aim of this paper. The paper also discusses additional requirements such as "virtual" wind inertia.

2015

Towards a standard model for research in agent-based modeling and simulation

Authors
Fachada, N; Lopes, VV; Martins, RC; Rosa, AC;

Publication
PeerJ Computer Science

Abstract
Agent-based modeling (ABM) is a bottom-up modeling approach, where each entity of the system being modeled is uniquely represented as an independent decision-making agent. ABMs are very sensitive to implementation details. Thus, it is very easy to inadvertently introduce changes which modify model dynamics. Such problems usually arise due to the lack of transparency in model descriptions, which constrains how models are assessed, implemented and replicated. In this paper, we present PPHPC, a model which aims to serve as a standard in agent based modeling research, namely, but not limited to, conceptual model specification, statistical analysis of simulation output, model comparison and parallelization studies. This paper focuses on the first two aspects (conceptual model specification and statistical analysis of simulation output), also providing a canonical implementation of PPHPC. The paper serves as a complete reference to the presented model, and can be used as a tutorial for simulation practitioners who wish to improve the way they communicate their ABMs.

2015

Identifying technology interaction opportunities within a gastroenterology exam room

Authors
Abrantes, D; Nunes, PP; Ribeiro, MD; Coimbra, MT;

Publication
MIE

Abstract
Gastric cancer is a serious disease that most people usually do not know they have until they start to get symptoms. Gastroenterology imaging is an essential tool for this battle, since an early diagnosis typically leads to a good prognosis. However, this is a rapidly evolving technological area with novel imaging devices such as capsule, narrow-band imaging or high-definition endoscopy. Adapting to these technologies has a high time-price cost, even for experienced clinicians, motivating the appearance of interactive environments that can accelerate these training processes. The GEMINI (Gastroenterology Made Interactive) project aims to create an interactive clinical decision support system (CDSS) that can be used to help with the diagnosis within a gastroenterology room during real endoscopic examinations. We used human computer interaction (HCI) support methodologies in order to identify interaction opportunities. As a final conclusion, the most promising avenue for interactions with CDSS is probably using mobile devices such as tablets, controlled by a nurse at the physician's request. As future work, we will prototype and evaluate such a system in a real hospital environment.

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