Towards Assume-Guarantee Profiles for Autonomous Vehicles

Rules or specifications for autonomous vehicles are currently formulated on a case-by-case basis, and put together in a rather ad-hoc fashion. As a step towards eliminating this practice, we propose a systematic procedure for generating a set of supervisory specifications for self-driving cars that are 1) associated with a distributed assume-guarantee structure and 2) characterizable by the notion of consistency and completeness. Besides helping autonomous vehicles make better decisions on the road, the assume-guarantee contract structure also helps address the notion of blame when undesirable events occur. We give several game-theoretic examples to demonstrate applicability of our framework

A generic, collaborative framework for internal constraint solving

Esta tesis propone un esquema genérico y cooperativo para CLP(Interval(X)) donde X es cualquier dominio de computación con estructura de retículo. El esquema, que está basado en la teoría de retículos, es un enfoque general para la satisfacción y op-timización de restricciones de intervalo así como para la cooperación de resolutores de intervalo definidos sobre dominios de computación con estructura de retículos, independientemente de la cardinalidad de estos. Nuestra propuesta asegura un enfoque transparente sobre el cual las restricciones, los dominios de computación y los mecanismos de propagación y cooperación, definidos entre las variables restringidas, pueden ser fácilmente especificados a nivel del usuario. La parte principal de la tesis presenta una especificación formal de este esquema.Los principales resultados conseguidos en esta tesis son los siguientes:Una comparativa global de la eficiencia y algunos aspectos de la expresividad de ocho sistemas de restricciones. Esta comparativa, realizada sobre el dominio finito y el dominio Booleano, muestra diferencias principales entre los sistemas de restricciones existentes.Para formalizar el marco de satisfacción de restricciones para CLP(Interval(X))hemos descrito el proceso global de resolución de restricciones de intervalo sobre cualquier retículo, separando claramente los procesos de propagación y división (ramificación) de intervalos. Una de las ventajas de nuestra propuesta es que la monótona de las restricciones esta implícitamente definida en la teoría. Además, declaramos un conjunto de propiedades interesantes que, bajo ciertas condiciones, son satisfechas por cualquier instancia del esquema genérico. Mas aún, mostramos que muchos sistemas de restricciones actualmente existentes satisfacen estas condiciones y, además, proporcionamos indicaciones sobre como extender el sistema mediante la especificación de otras instancias interesantes y novedosas. Nuestro esquema para CLP(Interval(X)) permite la cooperación de resolutores de manera que la información puede ⁰uir entre diferentes dominios de computación.Además, es posible combinar distintas instancias del esquema: por ejemplo, instancias bien conocidas tales como CLP(Interval(<)), CLP(Interval(Integer)),CLP(Interval(Set)), CLP(Interval(Bool)), y otras novedosas que son el resultado de la generación de nuevos dominios de computación definidos por el usuario, o incluso que surgen de la combinación de dominios ya existentes como puede ser CLP(Interval(X1 £ : : : £ Xn)). Por lo tanto, X puede ser instanciado a cualquier conjunto de dominios de computación con estructura de retículo de forma que su correspondiente instancia CLP(Interval(X)) permite una amplia flexibilidad en la definición de dominios en X (probablemente definidos por el usuario) y en la interaccion entre estos dominios.Mediante la implementacion de un prototipo, demostramos que un unico sistema,que este basado en nuestro esquema para CLP(Interval(X)), puede proporcionarsoporte para la satisfaccion y la optimizacion de restricciones as como para la cooperacion de resolutores sobre un conjunto conteniendo multiples dominios decomputacion. Ademas, el sistema sigue un novedoso enfoque transparente sujeto a una doble perspectiva ya que el usuario puede definir no solo nuevas restricciones y su mecanismo de propagacion, sino tambien nuevos dominios sobre los cuales nuevas restricciones pueden ser resueltas as como el mecanismo de cooperacion entre todos los dominios de computación (ya sean definidos por el usuario o predefinidos por el sistema).En nuestra opinión, esta tesis apunta nuevas y potenciales direcciones de investigación dentro de la comunidad de las restricciones de intervalo.Para alcanzar los resultados expuestos, hemos seguido los siguientes pasos (1) la elección de un enfoque adecuado sobre el cual construir los fundamentos teóricos de nuestro esquema genérico; (2) la construcción de un marco teórico genérico (que llamaremos el marco básico) para la propagación de restricciones de intervalo sobre cualquier retículo; (3) la integración, en el marco básico, de una técnica novedosa que facilita la cooperación de resolutores y que surge de la definición, sobre múltiples dominios, de operadores de restricciones y (4) la extensión del marco resultante para la resolución y optimización completa de las restricciones de intervalo.Finalmente presentamos clp(L), un lenguaje de programación lógica de restricciones de intervalo que posibilita la resolución de restricciones sobre cualquier conjunto de retículos y que esta implementado a partir de las ideas formalizadas en el marco teórico. Describimos una primera implementación de este lenguaje y desarrollamos algunos ejemplos de como usarla. Este prototipo demuestra que nuestro esquema para CLP(Interval(X)) puede ser implementado en un sistema único que, como consecuencia, proporciona, bajo un enfoque transparente sobre dominios y restricciones, cooperación de resolutores así como satisfacción y optimización completa de restricciones sobre diferentes dominios de computación

Towards Assume-Guarantee Profiles for Autonomous Vehicles

Rules or specifications for autonomous vehicles are currently formulated on a case-by-case basis, and put together in a rather ad-hoc fashion. As a step towards eliminating this practice, we propose a systematic procedure for generating a set of supervisory specifications for self-driving cars that are 1) associated with a distributed assume-guarantee structure and 2) characterizable by the notion of consistency and completeness. Besides helping autonomous vehicles make better decisions on the road, the assume-guarantee contract structure also helps address the notion of blame when undesirable events occur. We give several game-theoretic examples to demonstrate applicability of our framework

The Interrelationship between Formal and Informal Delcentralization and its Impact on Sub-Central Governance Performance: The Case of Vietnam

Formal and informal institutions are often viewed as complements or substitutes in empirical and theoretical works. However, no evidence of complementarities or substitutes is found in our empirical analysis of the interrelation between formal and informal decentralization across 64 provinces of Vietnam. This paper finds that the formally decentralized system of public service supply is accommodating the informal one, but informal decentralization in public order provision tends to compete with the existing ineffective formal system. This implies that the central government needs to reorganize the system of decentralizing the provision of public goods/services and public in order to make informal institutions complementary rather than rival or free-riding on formal ones.formal decentralization, informal decentralization, sub-central governance, accommodating, and competing

Optimal dynamic risk sharing when enforcement is a decision variable

JEL Classification: C73, D60, D91, K49dynamic risk sharing, enforcement

Communal Responsibility and the Coexistence of Money and Credit Under Anonymous Matching

Communal responsibility, a medieval institution studied by Greif (2006), supported the use of credit among European merchants in the absence of modern enforcement technologies. This paper shows how this mechanism helps to overcome enforcement problems in anonymous buyer/seller transactions. In a village economy version of the Lagos and Wright (2005) model, agents trading anonymously in decentralized markets can be identified by their citizenship and thus be held liable for each other. Enforceability within each village's centralized afternoon market ensures collateralization of credit in decentralized markets. In the resulting equilibrium, money and credit coexist in decentralized markets if the use of credit is costly. Our analysis easily extends itself to other payment systems like credit cards that provide a group identity to otherwise anonymous agents.Communal responsibility, anonymous matching, money demand, credit, bills of exchange

Corporate Governance: A Conceptual Analysis

According to the Chartered Institute of Corporate Governance, the term corporate governance is the system of rules, practices and processes by which a company is directed and controlled. Corporate Governance refers to the way in which companies are governed and to what purpose. It identifies who has power and accountability, and who makes decisions. It is, in essence, a toolkit that enables management and the board to deal more effectively with the challenges of running a company. Corporate governance ensures that businesses have appropriate decision-making processes and controls in place so that the interests of all stakeholders (shareholders, employees, suppliers, customers and the community) are balanced. Therefore, the aim of this paper is to provide a conceptual analysis of the term Corporate Governance. The paper further reviews the state of corporate governance in State-Owned Enterprises (SOEs) in Zambia. The paper uses traditional or narrative literature review as the methodology. The paper concludes that Corporate Governance has been a central issue in developing countries long before the recent spate of corporate scandals in advanced countries. The paper concludes that Corporate Governance gained tremendous importance due to economic liberalization and deregulation of industry and business. It is against this background that it has gained so much prominence in the running of State-Owned Enterprises. Keywords: Corporate Governance; Indicators of Corporate Governance; State-Owned Enterprises; SOEs, Zambia DOI: 10.7176/RJFA/14-17-05 Publication date:September 30th 2023

The calculation of optical absorption spectra using linear-scaling density-functional theory

The goal of the work presented in this thesis was to develop and implement a method for calculating optical absorption spectra for large electronic systems within a linear-scaling density-functional theory (LS-DFT) formalism. The key feature of this method was the development of a scheme for optimizing a set of localized orbitals to accurately represent unoccupied Kohn-Sham states, which are not well represented by the localized orbital basis sets used for ground state LS-DFT calculations. Three different schemes were compared for the calculation of unoccupied states using a one-dimensional “toy model” and the most promising of these, based on the use of a projection operator, was implemented in a fully-functional LS-DFT code. Using the toy model, two methods for the calculation of band structures within a localized basis set were investigated and some of the features required by localized basis sets in order to produce accurate band structures were identified. The method was tested by the application to both molecular and extended systems, with calculations of densities of states, band structures and optical absorption spectra. The results for the smaller systems were validated by comparison with a cubic-scaling plane-wave density-functional theory code, with which excellent agreement was achieved. Additionally, the method was shown to be linear-scaling for a conjugated polymer for system sizes up to 1000 atoms. The use of the projection method was shown to be crucial for calculating the above results, as was the implementation of a momentum operator based formalism for the calculation of spectra. Finally, it was shown that the method can be used to identify the transitions responsible for particular peaks in the spectra and is sensitive enough to distinguish between spectra for systems with very similar structures, demonstrating the capabilities of the method to aid the interpretation of experimental results