Thermography and Sonic Anemometry to Analyze Air Heaters in Mediterranean Greenhouses

The present work has developed a methodology based on thermography and sonic anemometry for studying the microclimate in Mediterranean greenhouses equipped with air heaters and polyethylene distribution ducts to distribute the warm air. Sonic anemometry allows us to identify the airflow pattern generated by the heaters and to analyze the temperature distribution inside the greenhouse, while thermography provides accurate crop temperature data. Air distribution by means of perforated polyethylene ducts at ground level, widely used in Mediterranean-type greenhouses, can generate heterogeneous temperature distributions inside the greenhouse when the system is not correctly designed. The system analyzed in this work used a polyethylene duct with a row of hot air outlet holes (all of equal diameter) that expel warm air toward the ground to avoid plant damage. We have observed that this design (the most widely used in Almería’s greenhouses) produces stagnation of hot air in the highest part of the structure, reducing the heating of the crop zone. Using 88 kW heating power (146.7 W∙m−2) the temperature inside the greenhouse is maintained 7.2 to 11.2 °C above the outside temperature. The crop temperature (17.6 to 19.9 °C) was maintained above the minimum recommended value of 10 °C

Conflicts in abstract argumentation systems

In this work we explore the inclusion of the notion of multiple argument conflicts, those in which two or more arguments are involved. In formal systems of defeasible argumentation, arguments for and against a proposition are produced and evaluated to verify the acceptability of that proposition. The development of argumentation systems has grown in the last years [AG95, BV, Dung93, PRAK, Sim92, GS99] but no consensus has been reached yet on some issues, such as the representation of arguments, the way they interact, and the output of that interaction. Even then, the main idea in these systems is that any proposition will be accepted as true if there exists an argument that supports it, and this argument is acceptable according to an analysis between it and its counterarguments. Therefore, in the set of arguments of the system, some of them will be acceptable or justified arguments, while others not. Almost every system of this kind is based on the notion of binary conflicts between arguments. We consider here the existence of a more complex form of conflict, how to solve it, and the corresponding acceptability semantic.Eje: Inteligencia Artificial Distribuida, Aspectos Teóricos de la Inteligencia Artificial y Teoría de la ComputaciónRed de Universidades con Carreras en Informática (RedUNCI

Dialoguing DeLP-based agents

A multi-agent system is made up of multiple interacting autonomous agents. It can be viewed as a society in which each agent performs its activity cooperating to achieve common goals, or competing for them. They establish dialogues via some kind of agent-communication language, under some communication protocol. We think argumentation is suitable to model several kind of dialogues in multi-agents systems. In this paper we define dialogues and persuasion dialogues between two agents using Defeasible Logic Programs as a knowledge base, together with an algorithm defining how this dialogue may be engaged. We also show an indication of how an agent could use opponent’s information for its own benefit.Eje: AgentesRed de Universidades con Carreras en Informática (RedUNCI

Abstract argumentation and dialogues between agents

A multiagent system (MAS) is made up of multiple interacting autonomous agents. It can be viewed as a society in which each agent performs its activity, cooperating to achieve common goals, or competing for them. Thus, every agent has the ability to do social interactions with other agents establishing dialogues via some kind of agent-communication language, under some communication protocol [6]. Argumentation is suitable to model several kind of dialogues in multi-agents systems. Some authors are actually using defeasible argumentation to model negotiation processes between agents [3, 7]. Our current research activities are related to the use of argumentation in agent’s interaction, such as negotiation among several participants, persuasion, acquisition of knowledge and other forms of social dialogue. Usually, argumentation appears as a mechanism to deal with disagreement between agents, for example when some conflict of interest is present. Argumentation can be used, not only to argue about something, but to know more about other agents: it is enough powerfull to play an important role in general social interaction in multiagents systems. The kind of arguments used in dialogues, and their relationship, depends on the type of dialogue involved. According to [8], dialogues can be classified in negotiation, where there is a conflict of interests, persuasion where there is a conflict of opinion or beliefs, indagation where there is a need for an explanation or proof of some proposition, deliberation or coordination where there is a need to coordinate goals and actions, and one special kind of dialogue called eristic based on personal conflicts. Except the last one, all these dialogues may exist in multi-agents systems as part of social activities among agents. Our aim is to define an abstract argumentation framework to capture the behaviour of these different dialogues, and we present here the main ideas behind this task and the new formal definitions. We are not interested in the logic used to construct arguments, nor the comparison method used. Our formulation completely abstracts from the internal structure of the arguments, considering them as moves made in a dialogue. We also consider multiagent systems as a set of multiple interacting autonomous agents.Eje: Inteligencia artificialRed de Universidades con Carreras en Informática (RedUNCI

Capturing the behaviour of inter-agent dialogues

A multiagent system (MAS) is made up of multiple interacting autonomous agents. It can be viewed as a society in which each agent performs its activity, cooperating to achieve common goals, or competing for them. Thus, every agent has the ability to do social interactions with other agents establishing dialogues via some kind of agent-communication language, under some communication protocol [13]. Argumentation has been used to model several kind of dialogues in multi-agents systems, such as negotiation or coordination [1, 7, 8, 5, 9]. Our current research activities are related to the use of argumentation in agent’s interaction, as a form of social dialogue. According to [15], dialogues can be classified in negotiation, where there is a conflict of interests, persuasion where there is a conflict of opinion or beliefs, indagation where there is a need for an explanation or proof of some proposition, deliberation or coordination where there is a need to coordinate goals and actions, and one special kind of dialogue called eristic based on personal conflicts. Except the last one, all this dialogues may exist in multi-agents systems as part of social activities among agents. We also study the use of argumentation formalisms to model the internal process of reasoning of an agent, often called monologues. Our aim is to define an abstract argumentation framework to capture the behaviour of these different dialogues. We are not interested in the logic used to construct arguments. Our formulation completely abstracts from the internal structure of the arguments, considering them as moves made in a dialogue. We also consider multiagent systems as a set of multiple interacting autonomous agents.Eje: Inteligencia artificial distribuida, aspectos teóricos de la inteligencia artificial y teoría de computaciónRed de Universidades con Carreras en Informática (RedUNCI

Argument comparison criteria analysis

In this work we show a possible form of classification of comparison methods in argumentation systems [AG95,BV,Dung93,PRAK,Sim92]. The main idea in these systems is that any proposition will be accepted as true if there exists an argument that supports it, and this argument is acceptable according to an analysis between it and its counterarguments. This analysis requires a process of comparison of conflicting arguments, in order to decide which one is preferable. After this dialectical analysis in the set of arguments of the system, some of them will be acceptable or justified arguments, while others not. In this classification, the argument comparison method plays a very important role.Eje: Inteligencia Artificial Distribuida, Aspectos Teóricos de la Inteligencia Artificial y Teoría de la ComputaciónRed de Universidades con Carreras en Informática (RedUNCI

Conflicts in abstract argumentation systems

In this work we explore the inclusion of the notion of multiple argument conflicts, those in which two or more arguments are involved. In formal systems of defeasible argumentation, arguments for and against a proposition are produced and evaluated to verify the acceptability of that proposition. The development of argumentation systems has grown in the last years [AG95, BV, Dung93, PRAK, Sim92, GS99] but no consensus has been reached yet on some issues, such as the representation of arguments, the way they interact, and the output of that interaction. Even then, the main idea in these systems is that any proposition will be accepted as true if there exists an argument that supports it, and this argument is acceptable according to an analysis between it and its counterarguments. Therefore, in the set of arguments of the system, some of them will be acceptable or justified arguments, while others not. Almost every system of this kind is based on the notion of binary conflicts between arguments. We consider here the existence of a more complex form of conflict, how to solve it, and the corresponding acceptability semantic.Eje: Inteligencia Artificial Distribuida, Aspectos Teóricos de la Inteligencia Artificial y Teoría de la ComputaciónRed de Universidades con Carreras en Informática (RedUNCI

An abstract argumentation framework with comparison criterion

We define an abstract argumentation framework that includes a binary symmetric relation representing argument conflicts, and a function used to evaluate conflicting arguments. In this framework it is clear how defeat relations are constructed, even when the arguments are treated abstractly. We also present a basic classification of comparison criterions and its impact on the set of accepted arguments. Finally, we define the concept of improvements of a comparison criterion and its relation with the fallacies presented in the framework.Eje: Agentes y Sistemas Inteligentes (ASI)Red de Universidades con Carreras en Informática (RedUNCI

P mito - implementación de una plataforma móvil utilizando Arduino

Una plataforma móvil es un dispositivo formado por un conjunto de sensores y por unos dispositivos de movilidad que dinamizan la cinemática de un objeto que típicamente es una superficie cuadrilátera. La característica típica de una plataforma móvil es su autonomía en ambientes no estructurados o inexplorados, la cual le permite navegar en una geografía determinada a través de la toma de decisiones que permitan evadir obstáculos estáticos y reaccionar a eventos dinámicos ambos relacionados con una tarea en ejecución que se determina mediante la asignación de unos objetivos que se requiere que la plataforma cumpla como por ejemplo seguir una línea evitando obstáculos. En la toma de decisiones que permiten que la plataforma móvil ejecute su tarea se requiere un sistema de control con módulos instrumentados que permitan establecer un conjunto de posibles soluciones y posteriormente seleccionar una estrategia que permita la localización de la plataforma su globalización, navegación y evasión de obstáculos

Application of Semi-Empirical Ventilation Models in A Mediterranean Greenhouse with Opposing Thermal and Wind Effects. Use of Non-Constant Cd (Pressure Drop Coefficient Through the Vents) and Cw (Wind Effect Coefficient)

The present work analyses the natural ventilation of a multi-span greenhouse with one roof vent and two side vents by means of sonic anemometry. Opening the roof vent to windward, one side vent to leeward, and the other side vents to windward (this last vent obstructed by another greenhouse), causes opposing thermal GT (m3 s−1) and wind effects Gw (m3 s−1), as outside air entering the greenhouse through the roof vent circulates downward, contrary to natural convection due to the thermal effect. In our case, the ventilation rate RM (h−1) in a naturally ventilated greenhouse fits a second order polynomial with wind velocity uo (RM = 0.37 uo2 + 0.03 uo + 0.75; R2 = 0.99). The opposing wind and thermal effects mean that ventilation models based on Bernoulli’s equation must be modified in order to add or subtract their effects accordingly—Model 1, in which the flow is driven by the sum of two independent pressure fields GM1=√(∣∣G2T±G2w∣∣) , or Model 2, in which the flow is driven by the sum of two independent fluxes GM2=|GT±Gw| . A linear relationship has been obtained, which allows us to estimate the discharge coefficient of the side vents (CdVS) and roof vent (CdWR) as a function of uo [CdVS = 0.028 uo + 0.028 (R2 = 0.92); CdWR = 0.036 uo + 0.040 (R2 = 0.96)]. The wind effect coefficient Cw was determined by applying models M1 and M2 proved not to remain constant for the different experiments, but varied according to the ratio uo/∆Tio0.5 or δ [CwM1 = exp(−2.693 + 1.160/δ) (R2 = 0.94); CwM2 = exp(−2.128 + 1.264/δ) (R2 = 0.98)]