On the solution of some non-local problems

summary:This paper deals with two types of non-local problems for the Poisson equation in the disc. The first of them deals with the situation when the function value on the circle is given as a combination of unknown function values in the disc. The other type deals with the situation when a combination of the value of the function and its derivative by radius on the circle are given as a combination of unknown function values in the disc. The existence and uniqueness of the classical solution of these problems is proved. The solutions are constructed in an explicit form

Norm reasoning services

Norms are used in open Multi-Agent Systems as a formal specification of deontic statements aimed at regulating the actions of agents and the interactions among them. In this paper, we propose a set of services facilitating the development of both non-normative and normative agents for norm-governed MAS. Specifically, we propose to provide agents with norm reasoning services. These services will help agent designers/developers to programme agents that consider norm reasoning without having to implement the needed mechanisms to reason about norms by themselves. This article shows how these services perform as well as the results of the experiments that we conducted to evaluate their performance

Refracting profiles and generalized holodiagrams

The recently developed concept of refracting profiles and that of refraction holodiagrams are combined so that the classical Abramson holodiagrams can be generalized taking into account a wider class of wave fronts and refraction at an interface, whenever regions of caustics are avoided. These holodiagrams are obtained as envelopes of specific families of Cartesian Ovals with an appropriate parametrization. Classical and reflecting holodiagrams are particular cases of this class. Several of the properties of the classical holodiagrams are shared by their richer generalized versionsComment: 12 pages, 7 figure

Norm Monitoring under Partial Action Observability

In the context of using norms for controlling multi-agent systems, a vitally important question that has not yet been addressed in the literature is the development of mechanisms for monitoring norm compliance under partial action observability. This paper proposes the reconstruction of unobserved actions to tackle this problem. In particular, we formalise the problem of reconstructing unobserved actions, and propose an information model and algorithms for monitoring norms under partial action observability using two different processes for reconstructing unobserved actions. Our evaluation shows that reconstructing unobserved actions increases significantly the number of norm violations and fulfilments detected

Resolving Multi-party Privacy Conflicts in Social Media

Items shared through Social Media may affect more than one user's privacy --- e.g., photos that depict multiple users, comments that mention multiple users, events in which multiple users are invited, etc. The lack of multi-party privacy management support in current mainstream Social Media infrastructures makes users unable to appropriately control to whom these items are actually shared or not. Computational mechanisms that are able to merge the privacy preferences of multiple users into a single policy for an item can help solve this problem. However, merging multiple users' privacy preferences is not an easy task, because privacy preferences may conflict, so methods to resolve conflicts are needed. Moreover, these methods need to consider how users' would actually reach an agreement about a solution to the conflict in order to propose solutions that can be acceptable by all of the users affected by the item to be shared. Current approaches are either too demanding or only consider fixed ways of aggregating privacy preferences. In this paper, we propose the first computational mechanism to resolve conflicts for multi-party privacy management in Social Media that is able to adapt to different situations by modelling the concessions that users make to reach a solution to the conflicts. We also present results of a user study in which our proposed mechanism outperformed other existing approaches in terms of how many times each approach matched users' behaviour

Multi-Agent Systems for Dynamic Forensic Investigation

In recent years Multi-Agent Systems have proven to be a useful paradigm for areas where inconsistency and uncertainty are the norm. Network security environments suffer from these problems and could benefit from a Multi-Agent model for dynamic forensic investigations. Building upon previous solutions that lack the necessary levels of scalability and autonomy, we present a decentralised model for collecting and analysing network security data to attain higher levels of accuracy and efficiency. The main contributions of the paper are: (i) a Multi-Agent model for the dynamic organisation of agents participating in forensic investigations; (ii) an agent architecture endowed with mechanisms for collecting and analysing network data; (iii) a protocol for allowing agents to coordinate and make collective decisions on the maliciousness of suspicious activity; and (iv) a simulator tool to test the proposed decentralised model, agents and communication protocol under a wide range of circumstances and scenarios

Photoionization-ion mobility spectrometer for non-targeted screening analysis or for targeted analysis coupling a Tenax TA column

Photoionization-ion mobility spectrometer (UV-IMS) can be used as a screening instrument to distinguish gasoline vapors from other similar samples, obtaining characteristic fingerprints in a quick and simple analysis. A non-targeted approach can be used to resolve many problems, moreover, this device can also be used for targeted analysis. In this case a Tenax TA trap was connected to the UV-IMS as a pre-separation step in order to identify compounds present in the gasoline gaseous sample, such as benzene and toluene. Firstly, target analytes were trapped in a Tenax TA column at ambient temperature and then they were desorbed thermally in an oven and connected to the UV-IMS for their analysis. Instrumental parameters such as temperature ramp, sample gas flow rate, drift gas flow rate, adsorption time and adsorption flow rate were optimized to obtain high sensitivity, selectivity and precision to determine benzene and toluene in vapour gaseous samples. The UV-IMS was calibrated with standard gases generated in an exponential dilution flask, obtaining a limit of quantification of 1.8 and 1.9 mg m-3 for benzene and toluene, respectively. The method developed was successfully applied to identify these analytes in air samples close to a gasoline spillag

An Active Learning Technique Enhanced with Electronic Polls

Only very few students answer questions like: “Did you understand this?”, “Do you have any question?”, etc. In this paper, we present an active learning technique that is based on the think-pair-share technique improved with the introduction of electronic polls to obtain anonymous instant feedback from the students. Electronic polls have been usually performed using Classroom Response Systems in the related literature, but these systems introduce a number of problems related to the excessive cost of the systems and the technical problems that they may cause to the instructors. Thus, we implement our active learning technique in an Interaction System that provides the benefits of supporting electronic polls but avoids the problems of Classroom Response Systems. We also present an example of how we applied our proposal to an Operating System lectures. Finally, we evaluate our proposal and demonstrate that the results we obtain are very similar to the ones obtained in the existing CRS literature without the problems that they introduce

Reasoning about norms under uncertainty in dynamic environments

The behaviour of norm-autonomous agents is determined by their goals and the norms that are explicitly represented inside their minds. Thus, they require mechanisms for acquiring and accepting norms, determining when norms are relevant to their case, and making decisions about norm compliance. Up until now the existing proposals on norm-autonomous agents assume that agents interact within a deterministic environment that is certainly perceived. In practise, agents interact by means of sensors and actuators under uncertainty with non-deterministic and dynamic environments. Therefore, the existing proposals are unsuitable or, even, useless to be applied when agents have a physical presence in some real-world environment. In response to this problem we have developed the n-BDI architecture. In this paper, we propose a multi-context graded BDI architecture (called n-BDI) that models norm-autonomous agents able to deal with uncertainty in dynamic environments. The n-BDI architecture has been experimentally evaluated and the results are shown in this paper. © 2014 Elsevier Inc. All rights reserved

A method to construct refracting profiles

We propose an original method for determining suitable refracting profiles between two media to solve two related problems: to produce a given wave front from a single point source after refraction at the refracting profile, and to focus a given wave front in a fixed point. These profiles are obtained as envelopes of specific families of Cartesian ovals. We study the singularities of these profiles and give a method to construct them from the data of the associated caustic.Comment: 12 pages, 5 figure