Optimal Reconfiguration of Formation Flying Spacecraft--a Decentralized Approach

This paper introduces a hierarchical, decentralized, and parallelizable method for dealing with optimization problems with many agents. It is theoretically based on a hierarchical optimization theorem that establishes the equivalence of two forms of the problem, and this idea is implemented using DMOC (Discrete Mechanics and Optimal Control). The result is a method that is scalable to certain optimization problems for large numbers of agents, whereas the usual “monolithic” approach can only deal with systems with a rather small number of degrees of freedom. The method is illustrated with the example of deployment of spacecraft, motivated by the Darwin (ESA) and Terrestrial Planet Finder (NASA) missions

Collision and evaporation avoidance for spacecraft formation

<p>Formation flying is an extremely promising approach to space operations with the potential to enable new types of missions and providing substantial increase in the performance of future space science and Earth observation applications. To successfully validate formation flying however requires the development of specific technologies and methodologies, which are beyond current state-of-the art in a wide range of diverse fields such as metrology and spacecraft guidance, navigation and control. A number of missions are currently under different stages of development to implement some of these stringent requirements.</p> <p>The paper develops and compares collision avoidance algorithms, demonstrating them within a 6 degrees of freedom, multi-spacecraft environment. At first a number of different collision avoidance scenarios will be identified alongside the triggers that will cause the algorithms to be activated. Once activated the collision avoidance algorithm must ensure corrective action to avoid catastrophic consequences to the mission.</p&gt

High-Tech Urban Agriculture in Amsterdam : An Actor Network Analysis

The agriculture and horticulture sector in the Netherlands is one of the most productive in the world. Although the sector is one of the most advanced and intense agricultural production systems worldwide, it faces challenges, such as climate change and environmental and social unsustainability of industrial production. To overcome these challenges, alternative food production initiatives have emerged, especially in large cities such as Amsterdam. Some initiatives involve producing food in the urban environment, supported by new technologies and practices, so-called high-tech urban agriculture (HTUA). These initiatives make cultivation of plants inside and on top of buildings possible and increase green spaces in urban areas. The emerging agricultural technologies are creating new business environments that are shape d by technology developers (e.g., suppliers of horticultural light emitting diodes (LED) and control environment systems) and developers of alternative food production practices (e.g., HTUA start-ups). However, research shows that the uptake of these technological innovations in urban planning processes is problematic. Therefore, this research analyzes the barriers that local government planners and HTUA developers are facing in the embedding of HTUA in urban planning processes, using the city of Amsterdam as a case study. This study draws on actor-network theory (ANT) to analyze the interactions between planners, technologies, technology developers and developers of alternative food production practices. Several concepts of ANT are integrated into a multi-level perspective on sustainability transitions (MLP) to create a new theoretical framework that can explain how interactions between technologies and planning actors transform the incumbent social\u2013technical regime. The configuration of interactions between social and material entities in technology development and adoption processes in Amsterdam is analyzed through the lens of this theoretical framework. The data in this study were gathered by tracing actors and their connections by using ethnographic research methods. In the course of the integration of new technologies into urban planning practices, gaps between technologies, technology developers, and planning actors have been identified. The results of this study show a lacking connection between planning actors and technology developers, although planning actors do interact with developers of alternative food production practices. These interactions are influenced by agency of artefacts such as visualizations of the future projects. The paper concludes that for the utilization of emerging technologies for sustainability transition of cities, the existing gap between technology developers and planning actors needs to be bridged through the integration of technology development visions in urban agendas and planning processe

Reconfiguration of Distributed Information Fusion System ? A case study

Information Fusion Systems are now widely used in different fusion contexts, like scientific processing, sensor networks, video and image processing. One of the current trends in this area is to cope with distributed systems. In this context, we have defined and implemented a Dynamic Distributed Information Fusion System runtime model. It allows us to cope with dynamic execution supports while trying to maintain the functionalities of a given Dynamic Distributed Information Fusion System. The paper presents our system, the reconfiguration problems we are faced with and our solutions.Comment: 6 pages - Preprint versio

Colombia Firm Energy Market

A firm energy market for Colombia is presented. Firm energy—the ability to provide energy in a dry period—is the product needed for reliability in Colombia’s hydro-dominated electricity market. The firm energy market coordinates investment in new resources to assure that sufficient firm energy is available in dry periods. Load procures in an annual auction enough firm energy to cover its needs. The firm energy product includes both a financial call option and the physical capability to supply firm energy. The call option protects load from high spot prices and improves the performance of the spot market during scarcity. The market provides strong performance incentives through the spot energy price. Market power is addressed directly: existing resources cannot impact the firm energy price. Since load is hedged from high spot prices, the market can rely on high prices to balance supply and demand during dry periods, rather than rationing.Auctions