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

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

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

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

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

Environmental consequences of Maltese MSW incineration

The intensity of Municipal Solid Waste (MSW) generation by human and economic activities causes environmental impacts, particularly critical in small insular countries, such as Malta. Thus, an investigation of the potential of Maltese MSW incineration with energy recovery was performed in this work focused on thermodynamic and land use aspects. The electricity potential of an MSW incinerator with associated electrical power plant to be built in Malta can be estimated as 5% of the total energy consumed in 2010 in the archipelago; alternatively, in a CHP configuration, it can also supply all the thermal energy required in 2010 for Multi-Effect Desalination. During its lifespan the plant can reduce deposition in landfills by at least 270,000 m2 (0.09% of the archipelago total area), diminishing also the potential for water and soil contamination. Last but not least, it can contribute to decrease the dependence on imported fossil fuels

Maximum Entropy and Bayesian Data Analysis: Entropic Priors

The problem of assigning probability distributions which objectively reflect the prior information available about experiments is one of the major stumbling blocks in the use of Bayesian methods of data analysis. In this paper the method of Maximum (relative) Entropy (ME) is used to translate the information contained in the known form of the likelihood into a prior distribution for Bayesian inference. The argument is inspired and guided by intuition gained from the successful use of ME methods in statistical mechanics. For experiments that cannot be repeated the resulting "entropic prior" is formally identical with the Einstein fluctuation formula. For repeatable experiments, however, the expected value of the entropy of the likelihood turns out to be relevant information that must be included in the analysis. The important case of a Gaussian likelihood is treated in detail.Comment: 23 pages, 2 figure

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