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Publications

2009

Scheduling of Head-Sensitive Cascaded Hydro Systems: A Nonlinear Approach

Authors
Catalao, JPS; Mariano, SJPS; Mendes, VMF; Ferreira, LAFM;

Publication
IEEE TRANSACTIONS ON POWER SYSTEMS

Abstract
In this paper, we propose a novel nonlinear approach to solve the short-term hydro scheduling problem under deregulation, considering head-dependency. The actual size of hydro systems, the continuous reservoir dynamics and constraints, the hydraulic coupling of cascaded hydro, systems, and the complexity associated with head-sensitive hydroelectric power generation still pose a real challenge to the modelers. These concerns are all accounted for in our approach. Results from a case study based on one of the main Portuguese cascaded hydro systems are presented, showing that the proposed nonlinear approach is proficient.

2009

EXPLORATORY INVESTIGATION OF E-BUSINESS CONSTRAINTS AMONG LARGE ORGANIZATIONS IN PORTUGAL

Authors
Morais, E; Pires, JA; Goncalves, R;

Publication
ICE-B 2009: PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON E-BUSINESS

Abstract
It is well recognized that e-business supports all parts of an organization's value chain, and offer valuable competitive advantages to firms. It is imperative for an organization to identify potential constraints to e-business in order to minimize the risk derived from its e-business initiative. Hence, in this paper, we explore a range of constraints that the literature suggests influences e-business evolution, so that organizations could be better equipped in anticipating any difficulties while in progress through their e-business initiatives. Thirteen hypotheses were formulated and tested. Questionnaires were applied to investigate the research problem. It was administered to 1000 managing directors of the biggest (according to the amount of business) Portuguese enterprises. Results suggest that organizational constraints are more critical, such as, conflict with traditional trading partners, conflict with traditional business and e-business initiatives, reengineering business processes and resistance to change, among other.

2009

An Analysis of Navigation Algorithms for Smartphones Using J2ME

Authors
Santos, AC; Tarrataca, L; Cardoso, JMP;

Publication
MOBILE WIRELESS MIDDLEWARE, OPERATING SYSTEMS, AND APPLICATIONS

Abstract
Embedded systems are considered one of the most potential areas for future innovations. Two embedded fields that will most certainly take a primary role in future innovations are mobile robotics and mobile computing. Mobile robots and srnartphones are growing in number and functionalities. becoming a presence in our daily life. In this paper, we study the current feasibility of a smartphone to execute navigation algorithms. As a test case, we use a smartphone to control an autonomous mobile robot. We tested three navigation problems: Mapping, Localization and Path Planning. For each of these problems, an algorithm has been chosen, developed in J2ME, and tested on the field. Results show the current mobile Java capacity for executing computationally demanding algorithms and reveal the real possibility of using smartphones for autonomous navigation.

2009

Unit Commitment in a Competitive and Emission Constrained Environment

Authors
Catalao, JPS; Mariano, SJPS; Mendes, VMF; Ferreira, LAFM;

Publication
IEEE LATIN AMERICA TRANSACTIONS

Abstract
This paper is on the unit commitment problem, considering not only the economic perspective, but also the environmental perspective. We propose a bi-objective approach to handle the problem with conflicting profit and emission objectives. Numerical results based on the standard IEEE 30-bus test system illustrate the proficiency of the proposed approach.

2009

A methodology for planning and controlling workload in a job-shop: a four-way decision-making problem

Authors
Moreira, MRA; Alves, RAFS;

Publication
INTERNATIONAL JOURNAL OF PRODUCTION RESEARCH

Abstract
There has been extensive research on workload and input-output control with the objective of improving manufacturing operations in job-shops. In this paper, a multiple decision-making scheme is proposed to plan and control operations in a general job-shop, and to improve delivery and workload related performance measures. The job-shop characteristics reinforce the need for designing a global system that controls both the jobs entering (order acceptance, due date setting and job release) and the work-in-process (dispatching), leading to an improvement of operational measures. Previous research has concentrated on scheduling a set of orders through the shop floor, according to some decision mechanism, in order to optimise some measure of performance (usually total lead time). This means that, since only a part of the decision-making system is being optimised, the resulting decision may be sub-optimal. In this paper it is shown that the performance of the different decision rules changes when they are considered simultaneously. Hence, a higher level approach, where the four decisions (order acceptance, due date setting, job release and dispatching) are considered at the same time, should be adopted to improve job-shop operational performance.

2009

IntelligentCart: Architecture of an Innovative System for the Acquisition of Products in Grocery Stores

Authors
Santos, DSS; Pereira, AMJ; Goncalves, RMRM;

Publication
INNOVATION AND KNOWLEDGE MANAGEMENT IN TWIN TRACK ECONOMIES: CHALLENGES & SOLUTIONS, VOLS 1-3

Abstract
Large grocery stores are nowadays used by millions of people for the acquisition of an enlarging number of products. Product acquisition represents a complex process that comprises lime spent in corridors, product location and checkout queues. On the other hand, it is becoming increasingly difficult for retailers to keep their clients loyal and to predict their needs due to the influence of competition and the lack of tools that discriminate consumption patterns. In this article it is presented the proposal of an architecture and solution of an innovative system for the acquisition of products in grocery stores (IntelligentCart). The IntelligentCart explores enlarging mobile technologies and automatic identification technologies (such as RFID) as a way to improve the quality of services provided by retailers and to augment the consumer value thus allowing to save time and money.

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