A Two-Stage Online Approach for Collaborative Multi-Agent Planning under Uncertainty

In a team of multiple agents, the pursuance of a common goal is a defining characteristic. Since agents may have different capabilities, and effects of actions may be uncertain, a common goal can generally only be achieved through a careful cooperation between the different agents. In this work, we propose a novel two-stage planner that combines online planning at both team level and individual level through a subgoal delegation scheme. The proposal brings the advantages of online planning approaches to the multi-agent setting. A number of modifications are made to a classical UCT approximate algorithm to (i) adapt it to the application domains considered, (ii) reduce the branching factor in the underlying search process, and (iii) effectively manage uncertain information of action effects by using information fusion mechanisms. The proposed online multi-agent planner reduces the cost of planning and decreases the temporal cost of reaching a goal, while significantly increasing the chance of success of achieving the common goal. 

Hierarchical Task Network Planning with Common-Sense Reasoning for Multiple-People Behaviour Analysis

Safety on public transport is a major concern for the relevant authorities. We
address this issue by proposing an automated surveillance platform which combines data from video, infrared and pressure sensors. Data homogenisation and integration is achieved by a distributed architecture based on communication middleware that resolves interconnection issues, thereby enabling data modelling. A common-sense knowledge base models and encodes knowledge about public-transport platforms and the actions and activities of passengers. Trajectory data from passengers is modelled as a time-series of human activities. Common-sense knowledge and rules are then applied to detect inconsistencies or errors in the data interpretation. Lastly, the rationality that characterises human behaviour is also captured here through a bottom-up Hierarchical Task Network planner that, along with common-sense, corrects misinterpretations to explain passenger behaviour. The system is validated using a simulated bus saloon scenario as a case-study. Eighteen video sequences were recorded with up to six passengers. Four metrics were used to evaluate performance. The system, with an accuracy greater than 90% for each of the four metrics, was found to outperform a rule-base system and a system containing planning alone.

A Collaborative Multiagent Framework based on Online Risk-Aware Planning and Decision-Making

Planning is an essential process in teams of multiple agents pursuing a common goal. When the effects of actions undertaken by agents are uncertain, evaluating the potential risk of such actions alongside their utility might lead to more rational decisions upon planning. This challenge has been recently tackled for single agent settings, yet domains with multiple agents that present diverse viewpoints towards risk still necessitate comprehensive decision making mechanisms that balance the utility and risk of actions. In this work, we propose a novel collaborative multi-agent planning framework that integrates (i) a team-level online planner under uncertainty that extends the classical UCT approximate algorithm, and (ii) a preference modeling and multicriteria group decision making approach that allows agents to find accepted and rational solutions for planning problems, predicated on the attitude each agent adopts towards risk. When utilised in risk-pervaded scenarios, the proposed framework can reduce the cost of reaching the common goal sought and increase effectiveness, before making collective decisions by appropriately balancing risk and utility of actions. 

Essays on optimal fiscal and monetary policies

Cette thèse se compose de trois articles sur les politiques budgétaires et monétaires optimales. Dans le premier article, J'étudie la détermination conjointe de la politique budgétaire et monétaire optimale dans un cadre néo-keynésien avec les marchés du travail frictionnels, de la monnaie et avec distortion des taux d'imposition du revenu du travail. Dans le premier article, je trouve que lorsque le pouvoir de négociation des travailleurs est faible, la politique Ramsey-optimale appelle à un taux optimal d'inflation annuel significativement plus élevé, au-delà de 9.5%, qui est aussi très volatile, au-delà de 7.4%. Le gouvernement Ramsey utilise l'inflation pour induire des fluctuations efficaces dans les marchés du travail, malgré le fait que l'évolution des prix est coûteuse et malgré la présence de la fiscalité du travail variant dans le temps. Les résultats quantitatifs montrent clairement que le planificateur s'appuie plus fortement sur l'inflation, pas sur l'impôts, pour lisser les distorsions dans l'économie au cours du cycle économique. En effet, il ya un compromis tout à fait clair entre le taux optimal de l'inflation et sa volatilité et le taux d'impôt sur le revenu optimal et sa variabilité. Le plus faible est le degré de rigidité des prix, le plus élevé sont le taux d'inflation optimal et la volatilité de l'inflation et le plus faible sont le taux d'impôt optimal sur le revenu et la volatilité de l'impôt sur le revenu. Pour dix fois plus petit degré de rigidité des prix, le taux d'inflation optimal et sa volatilité augmentent remarquablement, plus de 58% et 10%, respectivement, et le taux d'impôt optimal sur le revenu et sa volatilité déclinent de façon spectaculaire. Ces résultats sont d'une grande importance étant donné que dans les modèles frictionnels du marché du travail sans politique budgétaire et monnaie, ou dans les Nouveaux cadres keynésien même avec un riche éventail de rigidités réelles et nominales et un minuscule degré de rigidité des prix, la stabilité des prix semble être l'objectif central de la politique monétaire optimale. En l'absence de politique budgétaire et la demande de monnaie, le taux d'inflation optimal tombe très proche de zéro, avec une volatilité environ 97 pour cent moins, compatible avec la littérature. Dans le deuxième article, je montre comment les résultats quantitatifs impliquent que le pouvoir de négociation des travailleurs et les coûts de l'aide sociale de règles monétaires sont liées négativement. Autrement dit, le plus faible est le pouvoir de négociation des travailleurs, le plus grand sont les coûts sociaux des règles de politique monétaire. Toutefois, dans un contraste saisissant par rapport à la littérature, les règles qui régissent à la production et à l'étroitesse du marché du travail entraînent des coûts de bien-être considérablement plus faible que la règle de ciblage de l'inflation. C'est en particulier le cas pour la règle qui répond à l'étroitesse du marché du travail. Les coûts de l'aide sociale aussi baisse remarquablement en augmentant la taille du coefficient de production dans les règles monétaires. Mes résultats indiquent qu'en augmentant le pouvoir de négociation du travailleur au niveau Hosios ou plus, les coûts de l'aide sociale des trois règles monétaires diminuent significativement et la réponse à la production ou à la étroitesse du marché du travail n'entraîne plus une baisse des coûts de bien-être moindre que la règle de ciblage de l'inflation, qui est en ligne avec la littérature existante. Dans le troisième article, je montre d'abord que la règle Friedman dans un modèle monétaire avec une contrainte de type cash-in-advance pour les entreprises n’est pas optimale lorsque le gouvernement pour financer ses dépenses a accès à des taxes à distorsion sur la consommation. Je soutiens donc que, la règle Friedman en présence de ces taxes à distorsion est optimale si nous supposons un modèle avec travaie raw-efficace où seule le travaie raw est soumis à la contrainte de type cash-in-advance et la fonction d'utilité est homothétique dans deux types de main-d'oeuvre et séparable dans la consommation. Lorsque la fonction de production présente des rendements constants à l'échelle, contrairement au modèle des produits de trésorerie de crédit que les prix de ces deux produits sont les mêmes, la règle Friedman est optimal même lorsque les taux de salaire sont différents. Si la fonction de production des rendements d'échelle croissant ou decroissant, pour avoir l'optimalité de la règle Friedman, les taux de salaire doivent être égales.

Production planning, pricing and market coordination for news vendor problem with price dependent demand

Thesis (Ph.D.)--University of Washington, 2016-08

A assistência técnica nos habitats do MST e o papel do arquiteto e urbanista

This dissertation is about Architect and town planner inserts in the technical support of the Rural establishment and of the possibilities of changes in their habitat. It also looks for its participation through the production of those spaces with or without its performance through two references cases, in Rio Grande do Norte , one called settlement Eldorado de Carajás and another one called Maria da Paz. At first the process represents the model that was adopted systematically by Incra until the middle of the year 2000 with the sub-contracting of their construction work through small companies. These standardized projects which are executed without registration in the system CONFEA/CREA without demand of professional authorship and of technical responsibility of the work. But the process taken place at Maria da Paz s area was configured as one of the first initiatives that stopped with those practices. Consolidated through a partnership among UFRN MST and INCRA/RN, the Architect s technical support and town planner brought new technician-scientific organization and execution of the soil parcels and its habitat. The participation of UFRN was done through a group of studies in land reform and Habitat (GERAH) being this author and coordinator of the methodological proposal, based on the regressive-progressive method and in the inclusion of the conflict as responsible of the ruptures and transductions both done by Henry Léfèbvre and in the research action approached by Carlos Brandão. Therefore it included the process of social learning and collective production of new knowledge and attitudes in relation to the environment in the process called as attended self management in spite of the transformations happened with this new agent s participation. The people re-located to the new areas that got involved in the process and finished their constructions reelaborating the daily practice of the collective effort passed to the self management without technical support. Years later the implantation of those two experiences our research verified that there is a positive image concerning the Architect and town planner, related, most of all to the conception of the activities, orientation and execution of constructions projects and of acceptance of those professionals to the processes of implementation of the Habitats of the Rural establishments. This dissertation analyses this form of performance, from and beyond these images trying to find the professional, specificities or methodological in such a way to demonstrate the importance of its insertion in the formulation and attendance of the more of 100.000 habitats of Rural establishments of the land reform of the country that correspond to most of the housing social interest in the country side

A Relação professor-aluno e a afirmação do discente como sujeito do processo projetual: um estudo exploratório sobre a produção do trabalho final de graduação em arquitetura e urbanismo na UFC e na UFRN

This work deals with teacher-student relationship (TSR), held in a very special moment: the semester of graduation of architecture and urbanism, where students prepare the final work called Graduation Final Work (GFW). That is the last stage to obtain the title of architect and urban planner in Brazil. The text discusses this problem in several ways, emphasing the relationship between graduated student and his/her mentors into the consolidation process of the student as an actor of the planning process, here defined as "autonomy". The work is focused on understanding the TSR in order to elucidate its importance for improvement of teaching bases on development of the GFW, more than the relation between curriculum and institution. Related with the exploratory characteristic of this master thesis, methodologically, the field work happened through: (i) observation of mentorship guidance, (ii) interviews, and (iii) application of questionnaires to teachers and students. Participated 10 pairs of student and mentors of two federal university of Northeast: 05 pairs of the Federal University of Ceará (UFC) and 05 pairs of the Federal University of Rio Grande do Norte (UFRN). The results presented the development of the GFW as a difficult process / fearful for students, highlighting the main problem situations: the difficulty in choosing the theme, the super-sizing of the process, students' insecurities, and parental relationship with the supervisor process. Summing up, the work indicates that the students has a limited autonomy on the GFW process, which calls for a revision in order to promote the consolidation of the student autonomy, which must be observed for some positions recognition of the role of each actor in the process of orientation

The Productive use of Failure to Generate Witnesses from Divergent Proof Attempts for Coinduction

Coinduction is a proof rule. It is the dual of induction. It allows reasoning about non--well--founded structures such as lazy lists or streams and is of particular use for reasoning about equivalences. A central difficulty in the automation of coinductive proof is the choice of a relation (called a bisimulation). We present an automation of coinductive theorem proving. This automation is based on the idea of proof planning. Proof planning constructs the higher level steps in a proof, using knowledge of the general structure of a family of proofs and exploiting this knowledge to control the proof search. Part of proof planning involves the use of failure information to modify the plan by the use of a proof critic which exploits the information gained from the failed proof attempt. Our approach to the problem was to develop a strategy that makes an initial simple guess at a bisimulation and then uses generalisation techniques, motivated by a critic, to refine this guess, so that a larger class of coinductive problems can be automatically verified. The implementation of this strategy has focused on the use of coinduction to prove the equivalence of programs in a small lazy functional language which is similar to Haskell. We have developed a proof plan for coinduction and a critic associated with this proof plan. These have been implemented in CoClam, an extended version of Clam with encouraging results. The planner has been successfully tested on a number of theorems.

Dynamically balanced and plausible trajectory planning for human-like characters

International audience

Essays on optimal fiscal and monetary policies

Cette thèse se compose de trois articles sur les politiques budgétaires et monétaires optimales. Dans le premier article, J'étudie la détermination conjointe de la politique budgétaire et monétaire optimale dans un cadre néo-keynésien avec les marchés du travail frictionnels, de la monnaie et avec distortion des taux d'imposition du revenu du travail. Dans le premier article, je trouve que lorsque le pouvoir de négociation des travailleurs est faible, la politique Ramsey-optimale appelle à un taux optimal d'inflation annuel significativement plus élevé, au-delà de 9.5%, qui est aussi très volatile, au-delà de 7.4%. Le gouvernement Ramsey utilise l'inflation pour induire des fluctuations efficaces dans les marchés du travail, malgré le fait que l'évolution des prix est coûteuse et malgré la présence de la fiscalité du travail variant dans le temps. Les résultats quantitatifs montrent clairement que le planificateur s'appuie plus fortement sur l'inflation, pas sur l'impôts, pour lisser les distorsions dans l'économie au cours du cycle économique. En effet, il ya un compromis tout à fait clair entre le taux optimal de l'inflation et sa volatilité et le taux d'impôt sur le revenu optimal et sa variabilité. Le plus faible est le degré de rigidité des prix, le plus élevé sont le taux d'inflation optimal et la volatilité de l'inflation et le plus faible sont le taux d'impôt optimal sur le revenu et la volatilité de l'impôt sur le revenu. Pour dix fois plus petit degré de rigidité des prix, le taux d'inflation optimal et sa volatilité augmentent remarquablement, plus de 58% et 10%, respectivement, et le taux d'impôt optimal sur le revenu et sa volatilité déclinent de façon spectaculaire. Ces résultats sont d'une grande importance étant donné que dans les modèles frictionnels du marché du travail sans politique budgétaire et monnaie, ou dans les Nouveaux cadres keynésien même avec un riche éventail de rigidités réelles et nominales et un minuscule degré de rigidité des prix, la stabilité des prix semble être l'objectif central de la politique monétaire optimale. En l'absence de politique budgétaire et la demande de monnaie, le taux d'inflation optimal tombe très proche de zéro, avec une volatilité environ 97 pour cent moins, compatible avec la littérature. Dans le deuxième article, je montre comment les résultats quantitatifs impliquent que le pouvoir de négociation des travailleurs et les coûts de l'aide sociale de règles monétaires sont liées négativement. Autrement dit, le plus faible est le pouvoir de négociation des travailleurs, le plus grand sont les coûts sociaux des règles de politique monétaire. Toutefois, dans un contraste saisissant par rapport à la littérature, les règles qui régissent à la production et à l'étroitesse du marché du travail entraînent des coûts de bien-être considérablement plus faible que la règle de ciblage de l'inflation. C'est en particulier le cas pour la règle qui répond à l'étroitesse du marché du travail. Les coûts de l'aide sociale aussi baisse remarquablement en augmentant la taille du coefficient de production dans les règles monétaires. Mes résultats indiquent qu'en augmentant le pouvoir de négociation du travailleur au niveau Hosios ou plus, les coûts de l'aide sociale des trois règles monétaires diminuent significativement et la réponse à la production ou à la étroitesse du marché du travail n'entraîne plus une baisse des coûts de bien-être moindre que la règle de ciblage de l'inflation, qui est en ligne avec la littérature existante. Dans le troisième article, je montre d'abord que la règle Friedman dans un modèle monétaire avec une contrainte de type cash-in-advance pour les entreprises n’est pas optimale lorsque le gouvernement pour financer ses dépenses a accès à des taxes à distorsion sur la consommation. Je soutiens donc que, la règle Friedman en présence de ces taxes à distorsion est optimale si nous supposons un modèle avec travaie raw-efficace où seule le travaie raw est soumis à la contrainte de type cash-in-advance et la fonction d'utilité est homothétique dans deux types de main-d'oeuvre et séparable dans la consommation. Lorsque la fonction de production présente des rendements constants à l'échelle, contrairement au modèle des produits de trésorerie de crédit que les prix de ces deux produits sont les mêmes, la règle Friedman est optimal même lorsque les taux de salaire sont différents. Si la fonction de production des rendements d'échelle croissant ou decroissant, pour avoir l'optimalité de la règle Friedman, les taux de salaire doivent être égales.

Motion Planning and Controls with Safety and Temporal Constraints

Motion planning, or trajectory planning, commonly refers to a process of converting high-level task specifications into low-level control commands that can be executed on the system of interest. For different applications, the system will be different. It can be an autonomous vehicle, an Unmanned Aerial Vehicle(UAV), a humanoid robot, or an industrial robotic arm. As human machine interaction is essential in many of these systems, safety is fundamental and crucial. Many of the applications also involve performing a task in an optimal manner within a given time constraint. Therefore, in this thesis, we focus on two aspects of the motion planning problem. One is the verification and synthesis of the safe controls for autonomous ground and air vehicles in collision avoidance scenarios. The other part focuses on the high-level planning for the autonomous vehicles with the timed temporal constraints. In the first aspect of our work, we first propose a verification method to prove the safety and robustness of a path planner and the path following controls based on reachable sets. We demonstrate the method on quadrotor and automobile applications. Secondly, we propose a reachable set based collision avoidance algorithm for UAVs. Instead of the traditional approaches of collision avoidance between trajectories, we propose a collision avoidance scheme based on reachable sets and tubes. We then formulate the problem as a convex optimization problem seeking control set design for the aircraft to avoid collision. We apply our approach to collision avoidance scenarios of quadrotors and fixed-wing aircraft. In the second aspect of our work, we address the high level planning problems with timed temporal logic constraints. Firstly, we present an optimization based method for path planning of a mobile robot subject to timed temporal constraints, in a dynamic environment. Temporal logic (TL) can address very complex task specifications such as safety, coverage, motion sequencing etc. We use metric temporal logic (MTL) to encode the task specifications with timing constraints. We then translate the MTL formulae into mixed integer linear constraints and solve the associated optimization problem using a mixed integer linear program solver. We have applied our approach on several case studies in complex dynamical environments subjected to timed temporal specifications. Secondly, we also present a timed automaton based method for planning under the given timed temporal logic specifications. We use metric interval temporal logic (MITL), a member of the MTL family, to represent the task specification, and provide a constructive way to generate a timed automaton and methods to look for accepting runs on the automaton to find an optimal motion (or path) sequence for the robot to complete the task.

Shadedpath : aplicación Android para calcular rutas peatonales con mínima exposición solar

El trabajo de fin de grado consiste en realizar una aplicación móvil basada en Android [7]. Para calcular la ruta más sombreada desde un punto de origen a un punto de destino. Dicha aplicación móvil realizará peticiones a un servidor que estará ejecutando un programa que realizará el cálculo de rutas conforme a los parámetros que elegirá el usuario desde su móvil. Estos parámetros pueden ser: la hora de partida, la fecha y la importancia de la sombra a la hora de calcular la ruta. Siempre podremos elegir entre una ruta más corta o una más sombreada, según la importancia que le quiera dar el usuario. La lógica de la aplicación del lado del servidor que realiza el cálculo está basada en Open- TripPlanner, el cual usa algoritmos de búsqueda para encontrar el camino más corto. Sirviéndonos de dicho algoritmo realizaremos las modificaciones e implementaciones necesarias para calcular la ruta más sombreada.

A assistência técnica nos habitats do MST e o papel do arquiteto e urbanista

This dissertation is about Architect and town planner inserts in the technical support of the Rural establishment and of the possibilities of changes in their habitat. It also looks for its participation through the production of those spaces with or without its performance through two references cases, in Rio Grande do Norte , one called settlement Eldorado de Carajás and another one called Maria da Paz. At first the process represents the model that was adopted systematically by Incra until the middle of the year 2000 with the sub-contracting of their construction work through small companies. These standardized projects which are executed without registration in the system CONFEA/CREA without demand of professional authorship and of technical responsibility of the work. But the process taken place at Maria da Paz s area was configured as one of the first initiatives that stopped with those practices. Consolidated through a partnership among UFRN MST and INCRA/RN, the Architect s technical support and town planner brought new technician-scientific organization and execution of the soil parcels and its habitat. The participation of UFRN was done through a group of studies in land reform and Habitat (GERAH) being this author and coordinator of the methodological proposal, based on the regressive-progressive method and in the inclusion of the conflict as responsible of the ruptures and transductions both done by Henry Léfèbvre and in the research action approached by Carlos Brandão. Therefore it included the process of social learning and collective production of new knowledge and attitudes in relation to the environment in the process called as attended self management in spite of the transformations happened with this new agent s participation. The people re-located to the new areas that got involved in the process and finished their constructions reelaborating the daily practice of the collective effort passed to the self management without technical support. Years later the implantation of those two experiences our research verified that there is a positive image concerning the Architect and town planner, related, most of all to the conception of the activities, orientation and execution of constructions projects and of acceptance of those professionals to the processes of implementation of the Habitats of the Rural establishments. This dissertation analyses this form of performance, from and beyond these images trying to find the professional, specificities or methodological in such a way to demonstrate the importance of its insertion in the formulation and attendance of the more of 100.000 habitats of Rural establishments of the land reform of the country that correspond to most of the housing social interest in the country side

A Relação professor-aluno e a afirmação do discente como sujeito do processo projetual: um estudo exploratório sobre a produção do trabalho final de graduação em arquitetura e urbanismo na UFC e na UFRN

This work deals with teacher-student relationship (TSR), held in a very special moment: the semester of graduation of architecture and urbanism, where students prepare the final work called Graduation Final Work (GFW). That is the last stage to obtain the title of architect and urban planner in Brazil. The text discusses this problem in several ways, emphasing the relationship between graduated student and his/her mentors into the consolidation process of the student as an actor of the planning process, here defined as "autonomy". The work is focused on understanding the TSR in order to elucidate its importance for improvement of teaching bases on development of the GFW, more than the relation between curriculum and institution. Related with the exploratory characteristic of this master thesis, methodologically, the field work happened through: (i) observation of mentorship guidance, (ii) interviews, and (iii) application of questionnaires to teachers and students. Participated 10 pairs of student and mentors of two federal university of Northeast: 05 pairs of the Federal University of Ceará (UFC) and 05 pairs of the Federal University of Rio Grande do Norte (UFRN). The results presented the development of the GFW as a difficult process / fearful for students, highlighting the main problem situations: the difficulty in choosing the theme, the super-sizing of the process, students' insecurities, and parental relationship with the supervisor process. Summing up, the work indicates that the students has a limited autonomy on the GFW process, which calls for a revision in order to promote the consolidation of the student autonomy, which must be observed for some positions recognition of the role of each actor in the process of orientation

AUTONOMOUS POWER DISTRIBUTION SYSTEMS

Using robotic systems for many missions that require power distribution can decrease the need for human intervention in such missions significantly. For accomplishing this capability a robotic system capable of autonomous navigation, power systems adaptation, and establishing physical connection needs to be developed. This thesis presents developed path planning and navigation algorithms for an autonomous ground power distribution system. In this work, a survey on existing path planning methods along with two developed algorithms by author is presented. One of these algorithms is a simple path planner suitable for implementation on lab-size platforms. A navigation hierarchy is developed for experimental validation of the path planner and proof of concept for autonomous ground power distribution system in lab environment. The second algorithm is a robust path planner developed for real-size implementation based on lessons learned from lab-size experiments. The simulation results illustrates that the algorithm is efficient and reliable in unknown environments. Future plans for developing intelligent power electronics and integrating them with robotic systems is presented. The ultimate goal is to create a power distribution system capable of regulating power flow at a desired voltage and frequency adaptable to load demands.