2014
Authors
Gupta, V; Pereira, N; Gaur, S; Tovar, E; Rajkumar, R;
Publication
2014 IEEE 20TH INTERNATIONAL CONFERENCE ON EMBEDDED AND REAL-TIME COMPUTING SYSTEMS AND APPLICATIONS (RTCSA)
Abstract
Support for multiple concurrent applications is an important enabler for promoting the use of sensor networks as an infrastructure technology, where multiple users can deploy their applications independently. In such a scenario, different applications on a node may transmit packets at distinct periods, causing the node to change from sleep to active state more often, which negatively impacts the energy consumption of the whole network. In this paper, we propose to batch the transmissions together by defining a harmonizing period to align the transmissions from multiple applications at periodic boundaries. This harmonizing period is then leveraged to design a protocol that coordinates the transmissions across nodes and provides real-time guarantees in a multi-hop network. This protocol, which we call Network-Harmonized Scheduling (NHS), takes advantage of the periodicity introduced to assign offsets to nodes at different hop-levels such that collisions are always avoided, and deterministic behavior is enforced. NHS is a light-weight and distributed protocol that does not require any global state-keeping mechanism. We implemented NHS on the Contiki operating system and show how it can achieve a duty-cycle comparable to an ideal TDMA approach.
2014
Authors
Goncalves, J; Batista, J; Costa, P;
Publication
2014 IEEE EMERGING TECHNOLOGY AND FACTORY AUTOMATION (ETFA)
Abstract
In this paper it is described the prototyping of an instrumented chair that allows to fully-automate the "Timed Up and Go", the "30-Second Chair Stand" and the "Hand-Force "tests assessment. The presented functional chair prototype is a low cost approach that uses inexpensive sensors and the Arduino platform as the data acquisition board, with its software developed in LabVIEW. The "Timed up and go test" consists in measuring the time spent in the task execution of standing up from a chair, walk three meters with a maximum speed without running, turn a cone and going back to the initial position. The "30-Second Chair Stand" test consists in counting the number of completed chair stands in 30 seconds. It are agility, strength and endurance tests easy to setup and execute although they lack of repeatability, whenever the measures are taken manually, due to the rough errors that are introduced. The "Hand-Force" test consists in measuring the hand strength, the relevant data are the peak and average values of several tests. The referred data is important in order to evaluate hand rehabilitation treatment results.
2014
Authors
Belo Filho, MAF; Toledo, FMB; Almada Lobo, B;
Publication
JOURNAL OF THE OPERATIONAL RESEARCH SOCIETY
Abstract
Setup operations are significant in some production environments. It is mandatory that their production plans consider some features, as setup state conservation across periods through setup carryover and crossover. The modelling of setup crossover allows more flexible decisions and is essential for problems with long setup times. This paper proposes two models for the capacitated lot-sizing problem with backlogging and setup carryover and crossover. The first is in line with other models from the literature, whereas the second considers a disaggregated setup variable, which tracks the starting and completion times of the setup operation. This innovative approach permits a more compact formulation. Computational results show that the proposed models have outperformed other state-of-the-art formulation.
2014
Authors
Almeida, A; Azevedo, A;
Publication
FAIM 2014 - Proceedings of the 24th International Conference on Flexible Automation and Intelligent Manufacturing: Capturing Competitive Advantage via Advanced Manufacturing and Enterprise Transformation
Abstract
To cope with today market challenges and guarantee adequate competitive performances, companies have been decreasing their products life cycles, as well as increasing the number of product varieties and respective services available on their portfolio. Consequently, it has been observed an increasing in complexity in all domains, from product and process development, factory and production planning to factory operation and management. This reality implies that organizations should be able to compile and analyze, in a more agile way, the immense quantity of data generated, as well as apply the suitable tools that, based on this knowledge, will supports stakeholders to take decision envisioning future performance scenarios. Aiming to pursuing this vision was developed a proactive performance management framework, composed by a performance thinking methodology and a performance estimation engine. While the methodology developed is an extension of the Systems Dynamics approach for complex systems' performance management, on the other hand, the performance estimation engine is an innovative IT solution responsible by capturing lagging indicators, as well as estimate future performance behaviors. As main outcome of this research work, it was demonstrated that following a systematic and formal approach, it is possible to identify the feedback loops and respective endogenous and exogenous variables responsible by hindering the systems behavior, in terms of a specific KPI. Moreover, based on this enhanced understanding about manufacturing systems behavior, it was proved to be possible to estimate with high levels of confidence not only the present but also future performance behavior. From the combination of both qualitative and quantitative approaches, it was explored an enhanced learning machine algorithm capable to specify the curve of behavior, characteristic from a specific manufacturing system, and thus estimate future behaviors based on a set of leading indicators. In order to achieve these objectives, both Neural Networks and Unscented Kalman Filter for nonlinear estimation were applied. Important results and conclusions were extracted from an application case performed within a real automotive plant, which demonstrated the feasibility of this research towards a more proactive management approach.
2014
Authors
Cota, MP; Barroso, J; Leal Ferreira, SB; Fonseca, B; Mikropoulos, TA; Paredes, H;
Publication
DSAI
Abstract
2014
Authors
Cruz, F; Rocha, R; Goldstein, SC; Pfenning, F;
Publication
THEORY AND PRACTICE OF LOGIC PROGRAMMING
Abstract
We have designed a new logic programming language called LM (Linear Meld) for programming graph- based algorithms in a declarative fashion. Our language is based on linear logic, an expressive logical system where logical facts can be consumed. Because LM integrates both classical and linear logic, LM tends to be more expressive than other logic programming languages. LM programs are naturally concurrent because facts are partitioned by nodes of a graph data structure. Computation is performed at the node level while communication happens between connected nodes. In this paper, we present the syntax and operational semantics of our language and illustrate its use through a number of examples.
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