133 research outputs found
Collective Specialization for Evolutionary Design of a Multi-Robot System
Abstract. This research is positioned in the context of controller design for (simulated) multi-robot applications. Inspired by research in survey and exploration of unknown environments where a multi-robot system is to discover features of interest given strict time and energy constraints, we defined an abstract task domain with adaptable features of interest. Additionally, we parameterized the behavioral features of the robots, so that we could classify behavioral specialization in the space of these parameters. This allowed systematic experimentation over a range of task instances and types of specialization in order to investigate the advantage of specialization. These experiments also delivered a novel neuroevolution approach to controller design, called the collective specialization method. Results elucidated that this method derived multi-robot system controllers that outperformed a high performance heuristic and conventional neuro-evolution method.
Modeling Decentralized Organizational Change in Honeybee Societies
Multi-agent organizations in dynamic environments, need to have the ability to adapt to environmental changes to ensure a continuation of proper functioning. Such adaptations can be made through a centralized decision process or come from the individuals within the organization. In the domain of social insects, such as honeybees and wasps, organizations are known to adapt in a decentralized fashion to environmental changes. An organizational model for decentralized organizational change is presented that can aid in analyzing and designing such organizations. The model is specified by dynamic properties at different aggregation levels. At the lowest level such properties characterize the behavior of individual roles, which can be related to higher level properties that express important elements such as survival of an organization. A honeybee colony is used as a case study
Analysis of Meeting Protocols by Formalisation, Simulation and Verification
Organizations depend on regular meetings to carry out their everyday tasks. When carried out successfully, meetings offer a common medium for participants to exchange ideas and make decisions. However, many meetings suffer from unfocused discussions or irrelevant dialogues. To study meetings in detail, we first formalize general properties of meetings and a generic meeting protocol to specify how roles in a meeting should interact to realize these properties. This generic protocol is used as a starting point to study real-life meetings. Next, an example meeting is simulated using the generic meeting protocol. The general properties are formally verified in the simulation trace. Next, these properties are also verified formally against empirical data of a real meeting in the same context. A comparison of the two traces reveals that a real meeting is more robust since when exceptions happen and the rules of the protocol are violated, these exceptions are handled effectively. Given this observation, a more refined protocol is specified that includes exception-handling strategies. Based on this refined protocol a meeting is simulated that closely resembles the real meeting. This protocol is then validated against another set of data from another real meeting. By iteratively adding exception handling rules, the protocol is enhanced to handle a variety of situations successfully. © Springer Science+Business Media, LLC 2006
Investigation and modification of the inversed vortex phase field method for phase unwrapping
Поступила: 12.07.2021. Принята в печать: 05.08.2021.Received: 12.07.2021. Accepted: 05.08.2021.Предложена модификация метода встречного вихревого поля для развертывания фазы при интерферометрической обработке данных космических радиолокаторов с синтезированной апертурой. Модификация включает в себя выделение и развертывание низкочастотной фазы, получение интерферограммы остаточной фазы и ее фильтровую обработку. Произведена оценка точности получаемых при помощи алгоритма цифровых моделей рельефа на примере интерферометрической обработки радиолокационных данных ALOS PALSAR с использованием эталонных высотных данных. Произведено сравнение точности с другими распространенными алгоритмами развертывания фазы.The paper focuses on the problem of the phase unwrapping in spaceborne remote-sensing interferometric synthesized aperture radar (InSAR) systems. Major unwrapping methods and techniques are considered and the modification of the inversed vortex phase field method of phase unwrapping for interferometric data processing of space-borne synthesized aperture radars is proposed. The modification includes the separation and unwrapping of the low-frequency phase only, and obtaining of the residual phase interferogram, which phase range does not exceed 1–2 ambiguity height values. This approach significantly reduces the number of phase residues and increases the processing speed. The other modification implies filter processing of the residual phase without phase unwrapping, which includes iterative separation of the low-frequency using the Gaussian filter and phase subtraction. This approach moves phase fringes to the relief inflection areas, and is similar to the minimum-cost flow unwrapping results.
The computational complexity of the algorithm is proportional to the interferogram size and the number of the phase residues of the lowfrequency phase interferogram. The accuracy of digital elevation models obtained by the algorithm was estimated using the ALOS PALSAR radar data and the reference altitude data. The results show, that the accuracy is compared with the minimum-cost flow method, but has less computational complexity
Особливості скульптури поверхні зерен мінералів у паласитах
Наведено результати растрових електронно-мікроскопічних досліджень скульптури поверхні зерен мінералів із паласитів. Показано, що тонкі скульптурні особливості на поверхні зерен є чутливим індикатором фізико-хімічних умов утворення та еволюції паласитів у космосі й на Землі.The results of the scanning electron microscopic study of surface sculpture of mineral grains from pallasites are given. It is shown that the fine sculpture features belong to a sensitive indicator of physico-chemical conditions of pallasites formation and evolution in space and on the Earth
Emerging Artificial Societies Through Learning
The NewTies project is implementing a simulation in which societies of agents are expected to de-velop autonomously as a result of individual, population and social learning. These societies are expected to be able to solve environmental challenges by acting collectively. The challenges are in-tended to be analogous to those faced by early, simple, small-scale human societies. This report on work in progress outlines the major features of the system as it is currently conceived within the project, including the design of the agents, the environment, the mechanism for the evolution of language and the peer-to-peer infrastructure on which the simulation runs
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