Abstract: Studying alternative raw materials for biodiesel production is of major importance. The use of mixtures with incorporation of wastes is an environmental friendly alternative and might reduce biodiesel production costs. The objective of the present work was: (i) to study biodiesel production using waste frying oil mixed with pork lard and (ii) to understand how mixture composition influences biodiesel quality. Biodiesel was produced by transesterification and quality was evaluated through determination of several parameters according to EN 14214. The weight fraction of lard in the mixture varied from 0 to 1 in 0.2 intervals. Biodiesel production yields varied from 81.7 to 88.0 (wt%), the lowest yields being the ones obtained using waste frying oil and lard alone as raw materials. The obtained products fulfilled most of the determined quality specifications according to European biodiesel quality standard EN 14214. Minimum purity (96.5 wt%) was closely obtained when waste frying oil was used alone and when 0.2% of lard was incorporated in the raw material (96.3 wt%); however, it ranged from 93.9 to 96.3 (wt%) being always close to the limit. From the evaluation of the influence of mixture composition in biodiesel quality, it was possible to establish a model to be used for predicting some parameters of biodiesel resulting from mixtures of waste frying oil with lard when different lard contents are used.
Abstract: In order to answer the general question: “What does a simple agent with a limited life-time require for constructing a useful representation of the environment?" we propose a robot platform including the simplest probabilistic sensory and motor layers. Then we use the platform as a test-bed for evaluation of the navigational capabilities of the robot with different “brains". We claim that a protocognitive behavior is not a consequence of highly sophisticated sensory–motor organs but instead emerges through an increment of the internal complexity and reutilization of the minimal sensory information. We show that the most fundamental robot element, the short-time memory, is essential in obstacle avoidance. However, in the simplest conditions of no obstacles the straightforward memoryless robot is usually superior. We also demonstrate how a low level action planning, involving essentially nonlinear dynamics, provides a considerable gain to the robot performance dynamically changing the robot strategy. Still, however, for very short life time the brainless robot is superior. Accordingly we suggest that small organisms (or agents) with short life-time does not require complex brains and even can benefit from simple brain-like (reflex) structures. To some extend this may mean that controlling blocks of modern robots are too complicated comparative to their life-time and mechanical abilities.
Abstract: We proposed the use of a Toda-Rayleigh ring as a
central pattern generator (CPG) for controlling hexapodal robots. We
show that the ring composed of six Toda-Rayleigh units coupled to
the limb actuators reproduces the most common hexapodal gaits. We
provide an electrical circuit implementation of the CPG and test our
theoretical results obtaining fixed gaits. Then we propose a method
of incorporation of the actuator (motor) dynamics in the CPG. With
this approach we close the loop CPG – environment – CPG, thus
obtaining a decentralized model for the leg control that does not
require higher level intervention to the CPG during locomotion in
a nonhomogeneous environments. The gaits generated by the novel
CPG are not fixed, but adapt to the current robot bahvior.
Abstract: This paper presents anapproach of hybridizing two or more artificial intelligence (AI) techniques which arebeing used to
fuzzify the workstress level ranking and categorize the rating accordingly. The use of two or more techniques (hybrid approach)
has been considered in this case, as combining different techniques may lead to neutralizing each other-s weaknesses generating a
superior hybrid solution. Recent researches have shown that there is a
need for a more valid and reliable tools, for assessing work stress. Thus artificial intelligence techniques have been applied in this
instance to provide a solution to a psychological application. An overview about the novel and autonomous interactive model for analysing work-stress that has been developedusing multi-agent
systems is also presented in this paper. The establishment of the intelligent multi-agent decision analyser (IMADA) using hybridized technique of neural networks and fuzzy logic within the multi-agent based framework is also described.
Abstract: One approach to assess neural networks underlying the cognitive processes is to study Electroencephalography (EEG). It is relevant to detect various mental states and characterize the physiological changes that help to discriminate two situations. That is why an EEG (amplitude, synchrony) classification procedure is described, validated. The two situations are "eyes closed" and "eyes opened" in order to study the "alpha blocking response" phenomenon in the occipital area. The good classification rate between the two situations is 92.1 % (SD = 3.5%) The spatial distribution of a part of amplitude features that helps to discriminate the two situations are located in the occipital regions that permit to validate the localization method. Moreover amplitude features in frontal areas, "short distant" synchrony in frontal areas and "long distant" synchrony between frontal and occipital area also help to discriminate between the two situations. This procedure will be used for mental fatigue detection.
Abstract: The aim of this paper is to propose a mathematical
model to determine invariant sets, set covering, orbits and, in
particular, attractors in the set of tourism variables. Analysis was
carried out based on a pre-designed algorithm and applying our
interpretation of chaos theory developed in the context of General
Systems Theory. This article sets out the causal relationships
associated with tourist flows in order to enable the formulation of
appropriate strategies. Our results can be applied to numerous cases.
For example, in the analysis of tourist flows, these findings can be
used to determine whether the behaviour of certain groups affects that
of other groups and to analyse tourist behaviour in terms of the most
relevant variables. Unlike statistical analyses that merely provide
information on current data, our method uses orbit analysis to
forecast, if attractors are found, the behaviour of tourist variables in
the immediate future.
Abstract: We consider a network of two M/M/1 parallel queues having the same poisonnian arrival stream with rate λ. Upon his arrival to the system a customer heads to the shortest queue and stays until being served. If the two queues have the same length, an arriving customer chooses one of the two queues with the same probability. Each duration of service in the two queues is an exponential random variable with rate μ and no jockeying is permitted between the two queues. A new numerical method, based on linear programming and convex optimization, is performed for the computation of the steady state solution of the system.
Abstract: There is increasing pressure on, and decline of
mopane woodlands due to increasing use and competition for
mopane resources in Zimbabwe in Namibia. Community management strategies, based largely on local knowledge are
evidently unable to cope. Research has generated potentially useful
information for mopane woodland management, but this information
has not been utilized. The work reported in this paper sought to add value to research work conducted on mopane woodlands by
developing effective community-based mopane woodland
management regimes that were based on both local and scientific
knowledge in Zimbabwe and Namibia. The conditions under which research findings were likely to be adopted for mopane woodland management by communities were investigated. The study was conducted at two sites each in Matobo and Omusati Districts in Zimbabwe and Namibia respectively. The mopane woodland
resources in the two study areas were assessed using scientific
ecological methods. A range of participatory methods was used to collect information on use of mopane woodland resources by communities, institutional arrangements governing access to and use
of these resources and to evaluate scientific knowledge for
applicability in local management regimes. Coppicing, thinning and
pollarding were the research generated management methods evaluated. Realities such as availability of woodland resources and
social roles and responsibilities influenced preferences for woodland
management interventions
Abstract: In this paper we study a system composed by carbon
nanotube (CNT) and bundle of carbon nanotube (BuCNT) interacting
with a specific fatty acid as molecular probe. Full system is
represented by open nanotube (or nanotubes) and the linoleic acid
(LA) relaxing due the interaction with CNT and BuCNT. The LA has
in his form an asymmetric shape with COOH termination provoking
a close BuCNT interaction mainly by van der Waals force field. The
simulations were performed by classical molecular dynamics with
standard parameterizations.
Our results show that these BuCNT and CNT are dynamically
stable and it shows a preferential interaction position with LA
resulting in three features: (i) when the LA is interacting with CNT
and BuCNT (including both termination, CH2 or COOH), the LA is
repelled; (ii) when the LA terminated with CH2 is closer to open
extremity of BuCNT, the LA is also repelled by the interaction
between them; and (iii) when the LA terminated with COOH is
closer to open extremity of BuCNT, the LA is encapsulated by the
BuCNT. These simulations are part of a more extensive work on
searching efficient selective molecular devices and could be useful to
reach this goal.
Abstract: International literature emphasizes on the concern regarding the phenomenon of aggression in hospital. This paper focuses on the reality of aggressive interactions reigning within an emergency triage involving three chaps of protagonists: the professionals, the patients and their carers. The data collection was made from a grid of observation, in which the various variables exposed in the literature were integrated. They observations took place around the clock, for three weeks, at the rate of one week a month. In this research 331 aggressive interactions have been listed and analyzed by means of the software SPSS. This research is one of the very few continuous observation surveys in the literature. It shows the various human factors at play in the emergence of aggressive interaction. The data may be used both for taking steps in primary prevention, thanks to the analysis of interaction modes, and in secondary prevention by integrating the useful results in situational prevention.