STRATEGY MANAGEMENT IN A MULTI-AGENT SYSTEM USING NEURAL NETWORKS FOR INDUCTIVE AND EXPERIENCE-BASED LEARNING

Intelligent agents and multi-agent systems prove to be a promising paradigm for solving problems in a distributed, cooperative way. Neural networks are a classical solution for ensuring the learning ability of agents. In this paper, we analyse a multi-agent system where agents use different training algorithms and different topologies for their neural networks, which they use to solve classification and regression problems provided by a user. Out of the three training algorithms under investigation, Backpropagation, Quickprop and Rprop, the first demonstrates inferior performance to the other two when considered in isolation. However, by optimizing the strategy of accepting or rejecting tasks, Backpropagation agents succeed in outperforming the other types of agents in terms of the total utility gained. This strategy is learned also with a neural network, by processing the results of past experiences. Therefore, we show a way in which agents can use neural network models for both external purposes and internal ones.agents, learning, neural networks, strategy management multi-agent system.

Adaptive multiagent system for seismic emergency management

Presently, most multiagent frameworks are typically programmed in Java. Since the JADE platform has been recently ported to .NET, we used it to create an adaptive multiagent system where the knowledge base of the agents is managed using the CLIPS language, also called from .NET. The multiagent system is applied to create seismic risk scenarios, simulations of emergency situations, in which different parties, modeled as adaptive agents, interact and cooperate.adaptive systems, risk management, seisms.

Design patterns for multi-agent simulations

The advent of mobile agent technology has brought along a few difficulties in designing a stable, efficient and scalable system for a certain problem. Agent-based simulations prove to be powerful tools for economic analyses. In this paper we aim at describing a set of design patterns which were specifically built for agents and multi-agent systems. The details of each design pattern discussed are presented and the possible applications and known issues are noted. In order to aid the software designers, we provide some examples of the basic implementation of these patterns using the JADE multi-agent framework.intelligent agent, multi-agent design, multi-agent simulation.

A Review of Platforms for the Development of Agent Systems

Agent-based computing is an active field of research with the goal of building autonomous software of hardware entities. This task is often facilitated by the use of dedicated, specialized frameworks. For almost thirty years, many such agent platforms have been developed. Meanwhile, some of them have been abandoned, others continue their development and new platforms are released. This paper presents a up-to-date review of the existing agent platforms and also a historical perspective of this domain. It aims to serve as a reference point for people interested in developing agent systems. This work details the main characteristics of the included agent platforms, together with links to specific projects where they have been used. It distinguishes between the active platforms and those no longer under development or with unclear status. It also classifies the agent platforms as general purpose ones, free or commercial, and specialized ones, which can be used for particular types of applications.Comment: 40 pages, 2 figures, 9 tables, 83 reference

Surgery in tumors of the lateral ventricles – last 8 years experience

Introduction: Tumors of the lateral ventricle are rare lesions including a large variety of benign or malignant tumors. These tumors could originate in the ventricular wall or arising and expanding within the lateral ventricle from the surrounding neural structures. The purpose of this study is to discuss postoperative results and factors that affected the preference for transcallosal or transcortical approach.Material and methods: We performed a retrospective study, lasted between 2005-2013, that comprised 26 consecutive patients who underwent operation for lateral ventricle tumors. The main clinical symptoms and signs were associated with the localization and size of the tumors. Cerebral computed tomography and magnetic resonance imaging were used to determine the location and expansion of each tumor. The transcortical approach was used in 17 patients and the transcallosal approach was used in 9 patients.Results: Total tumor resection was achieved in 73% of cases (19 patients). Most frequent histological tumor’s type was glioblastoma, choroid plexus papilloma, ependymoma and meningioma. Signs of increased intracranial pressure were most dominant. One patient died because of postoperative intraventricular hemorrhage. Additional neurological deficits were seen in 3 patients and postoperative seizure occurred in three patients. One patient with preoperative hydrocephalus required ventriculo-peritoneal shunting after tumor’s resection. Two patients developed postoperative epidural hematoma and one required reoperation. 15 of 26 patients received postoperative radiotherapy and 6 of them received adjuvant chemotherapy. The mean duration of postoperative evaluation was 24,32 (range 5-92). Excepting the cases with subtotal resection, two patients were reoperated for recurrences.Conclusions: The nature, size, location and vascularization of intraventricular tumors are the most important elements influencing the choice of surgical approach. Surgeons must evaluate all these factors and prefer the short and safe way to remove the tumor

Large olfactory groove meningiomas: Clinical outcome considering different surgical approaches

Olfactory groove meningiomas (OGMs) account for 4.5 to 13% of all intracranial meningiomas (1,2). They arise in the anterior cranial fossa at the cribriform plate of the ethmoid bone and the area of the suture adjoining the planum sphenoidale.We performed a large retrospective study of 98 patients (59 females and 39 males) evaluated and operated in the Neurosurgical Department of the National Institute of Neurology and Neurovascular Diseases between 1979 – 2009. This represented 7.93% of all intracranial meningiomas operated in our department (1235 cases). These operations were done by or under the supervision of the senior neurosurgeon (LD). For the surgical removal of the OGMs we used both frontolateral (67 cases) or bifrontal approaches (31 cases). We achieved total removal of the meningioma in most of the cases (93.9%), meaning in 66 patients operated through unilateral frontolateral craniotomy (98.5%), and in 26 patients operated through bifrontal craniotomy (83.9%). As postoperative complications, were encountered: subdural hygroma, postoperative hemorrhage, cerebrospinal fluid (CSF) leak, postoperative seizures, diffuse cerebral edema and local infection. Postoperative mortality was 7.14% (7 patients). Frontolateral approach allowed, even in large OGMs, very good postoperative results, with high rates of total tumor resection and low rates of morbidity and mortality

Experimental analysis and mathematical prediction of Cd(II) removal by biosorption using support vector machines and genetic algorithms

We investigated the bioremoval of Cd(II) in batch mode, using dead and living biomass of Trichoderma viride. Kinetic studies revealed three distinct stages of the biosorption process. The pseudo-second order model and the Langmuir model described well the kinetics and equilibrium of the biosorption process, with a determination coefficient, R2 > 0.99. The value of the mean free energy of adsorption, E, is less than 16 kJ/mol at 25°C, suggesting that, at low temperature, the dominant process involved in Cd(II) biosorption by dead T. viride is the chemical ion-exchange. With the temperature increasing to 4050°C, E values are above 16 kJ/mol, showing that the particle diffusion mechanism could play an important role in Cd(II) biosorption. The studies on T. viride growth in Cd(II) solutions and its bioaccumulation performance showed that the living biomass was able to bioaccumulate 100% Cd(II) from a 50 mg/L solution at pH 6.0. The influence of pH, biomass dosage, metal concentration, contact time and temperature on the bioremoval efficiency was evaluated to further assess the biosorption capability of the dead biosorbent. These complex influences were correlated by means of a modeling procedure consisting in data driven approach in which the principles of artificial intelligence were applied with the help of support vector machines (SVM), combined with genetic algorithms (GA). According to our data, the optimal working conditions for the removal of 98.91% Cd(II) by T. viride were found for an aqueous solution containing 26.11 mg/L Cd(II) as follows: pH 6.0, contact time of 3833 min, 8 g/L biosorbent, temperature 46.5°C. The complete characterization of bioremoval parameters indicates that T. viride is an excellent material to treat wastewater containing low concentrations of metal