Multiagent Cooperative Search for Portfolio Selection

We present a new multiagent model for the multiperiod portfolio selection problem. A system of cooperative agents divide initial wealth and follow individual worst-case optimal investment strategies from random portfolios, sharing their final profits and losses. The multiagent system achieves better average-case performance than a single agent with the same initial wealth in a simple stochastic market. A further increase in performance is achieved through communication of hints between agents and probabilistic strategy-switching. However, this explicit cooperation is redundant in a market that approximates the Capital Asset Pricing Model, a model of equilibrium stock price dynamics. Journal of Economic Literature Classification Numbers: C63, C73, D83, G11.Engineering and Applied Science

Cooperative Multiagent Search for Portfolio Selection

We present a new multiagent model for the multiperiod portfolio selection problem. Individual agents receive a share of initial wealth, and follow an investment strategy that adjusts their portfolio as they observe movements of the market over time. The agents share their wealth at the end of the final investment period. We show that a multiagent system can outperform a single agent that invests all the wealth in a simple stochastic market environment. Furthermore, a cooperative multiagent system, with a simple communication mechanism of explicit hint exchange, achieves a further increase in performance. Finally we show that communication is redundant in a more realistic market that satisfies the constraints between volatility and return implied by the Capital Asset Pricing Model.Engineering and Applied Science

Assessing the environmental and economic performance of alternative car chassis

The main objective of this study is to evaluate the life cycle environmental and economic performance of a car multimedia chassis containing metallic parts, and compare it with new, totally plastic, chassis designs. The Life Cycle Assessment and Life Cycle Costing methodologies were applied. All systems boundaries consider material and parts production, and the use and End of Life (EoL) phases of the chassis. The results showed that the former system has a higher environmental impact, the material production being the main contributor followed by the use phase, and Fossil depletion the most burdensome impact category. All total plastic scenarios enable approximately 40% weight reduction, mitigating both the Global Warming Potential and the Cumulative Energy Demand environmental impacts until the end of the use phase. However, this result is inverted including the EoL phase, as recycling the metal is more favourable than incinerating the polymer and recovering energy. All TPC scenarios present a higher cost. Although their assembly and use phases costs are lower than the corresponding BSL ones, this does not mitigate the higher material and production costs. Again, at EoL, recycling the metal is more cost favourable. The present work evidences that to make sustainable decisions environmental and economic considerations should be concurrently contemplated in product development.The present work was partially financed by the Portuguese Incentive System for Research and Technological Development, as co-promotion Project nº 36265/2013 (Project HMIExcel – 2013-2015). The authors thank the support of the Bosch Car Multimedia Portugal, S.A. company throughout the inventory phase of the study. Two of the authors (CAB, AJP) acknowledge the funding received from FCT, the Portuguese Foundation for Science and Technology, through project UID/CTM/50025/2013 and from the COMPETE 2020 Programme under project POCI-01-0145-FEDER-00768

The use of a three-point support flexural test to predict the stiffness of anisotropic composite plates in bending

http://www.sciencedirect.com/science/journal/01429418Anisotropic polymeric matrix composite discs supported on three points were subjected to a non-destructive bending test to study their behaviour in complex flexural loading situations. The results show that the flexural behaviour of the composites depends on several factors, such as fibre orientation, laminate stacking, surface waviness and moulding temperature. The experimental data were compared with those obtained from the finite element program software Algor. Differences up to 13% were found between the experimental and simulated values of the flexural stiffness. In spite of that, it was concluded that the non-destructive test used is a useful tool to predict the behaviour of anisotropic composites and to validate the results obtained from computer FEM analysis

A Framework for Efficient Adaptively Secure Composable Oblivious Transfer in the ROM

Oblivious Transfer (OT) is a fundamental cryptographic protocol that finds a number of applications, in particular, as an essential building block for two-party and multi-party computation. We construct a round-optimal (2 rounds) universally composable (UC) protocol for oblivious transfer secure against active adaptive adversaries from any OW-CPA secure public-key encryption scheme with certain properties in the random oracle model (ROM). In terms of computation, our protocol only requires the generation of a public/secret-key pair, two encryption operations and one decryption operation, apart from a few calls to the random oracle. In~terms of communication, our protocol only requires the transfer of one public-key, two ciphertexts, and three binary strings of roughly the same size as the message. Next, we show how to instantiate our construction under the low noise LPN, McEliece, QC-MDPC, LWE, and CDH assumptions. Our instantiations based on the low noise LPN, McEliece, and QC-MDPC assumptions are the first UC-secure OT protocols based on coding assumptions to achieve: 1) adaptive security, 2) optimal round complexity, 3) low communication and computational complexities. Previous results in this setting only achieved static security and used costly cut-and-choose techniques.Our instantiation based on CDH achieves adaptive security at the small cost of communicating only two more group elements as compared to the gap-DH based Simplest OT protocol of Chou and Orlandi (Latincrypt 15), which only achieves static security in the ROM

Harold Jeffreys's Theory of Probability Revisited

Published exactly seventy years ago, Jeffreys's Theory of Probability (1939) has had a unique impact on the Bayesian community and is now considered to be one of the main classics in Bayesian Statistics as well as the initiator of the objective Bayes school. In particular, its advances on the derivation of noninformative priors as well as on the scaling of Bayes factors have had a lasting impact on the field. However, the book reflects the characteristics of the time, especially in terms of mathematical rigor. In this paper we point out the fundamental aspects of this reference work, especially the thorough coverage of testing problems and the construction of both estimation and testing noninformative priors based on functional divergences. Our major aim here is to help modern readers in navigating in this difficult text and in concentrating on passages that are still relevant today.Comment: This paper commented in: [arXiv:1001.2967], [arXiv:1001.2968], [arXiv:1001.2970], [arXiv:1001.2975], [arXiv:1001.2985], [arXiv:1001.3073]. Rejoinder in [arXiv:0909.1008]. Published in at http://dx.doi.org/10.1214/09-STS284 the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org

Population dynamic of ring nematode in peach orchard managed with castor bean cake and millet crop.

Edição dos Proceedings do 6th International Congress of Nematology, Cape Town, South Africa, May 2014

Energy recovery and impact on land use of Maltese municipal solid waste incineration

An investigation of the potential of Maltese Municipal Solid Waste (MSW) for energy recovery is carried in this work together with a preliminary assessment of the corresponding economic and land use impacts. MSW composition data was collected to evaluate the waste combustion enthalpy. Data from 1997 to 2010 allowed the conclusion that an incinerator with a capacity of 32,500kg/h can treat all the waste expectably generated in Malta during next 20 years. The thermodynamics of the steam cycle combined with elemental analysis were applied to study the contribution for power (PG) and Combined Heat and Power (CHP) generation. The thermal energy was analyzed assuming its use in desalination. The best scenario considered corresponds to a potential electric power of 10 MW (PG) or to a maximum 4.8 million m3/year of desalinated water combined with and 7.25 MW (CHP). It was concluded that incineration and CHP have the greatest potential to maximize revenues, due to the optimal combination of heat production and electricity generation. Finally, a calculation of the savings in land use due to the MSW incineration implementation was performed. Those savings could represent from 13,500 to 17,000 m2 per year, a decisive benefit for Malta.The authors acknowledge the financial support of IPC through project PEst-C/CTM/LA0025/2011 (Strategic Project-LA 25-2011-2012) for the execution of the work described herein. The work would not have been possible without the support of various individuals and institutions in Portugal and in the Maltese islands. In Portugal, we are grateful for the information provided by LIPOR - Central de Valorizacao Energetica, at Maia, which allowed us to validate the incineration data gathered in the literature. Our sincere thanks are also addressed to Prof. Toste de Azevedo, Viriato Semiao, Zdena Zsigraiova, Gilberto Tavares and Rui Martins, of the Mechanical Engineering Department at the Instituto Superior Tecnico, who helped us with the thermodynamic calculations and with other important incineration related information. We acknowledge the help of Prof. Godfrey Pirotta, Edward Mallia, Tonio Sant and Maria Attard of the University of Malta for their availability to explain and contextualize the islands' energy and environment policies. Finally, the assistance of WasteServ Malta Corporation, which provided actual information about MSW generation and further details about the Maltese waste management system, should also be acknowledged