Мультиагентный метод оптимизации с адаптивными параметрами

Исследован мультиагентный подход к оптимизации многомерных нелинейных функций. Разработан мультиагентный метод оптимизации с адаптивными параметрами. Проведены эксперименты по поиску глобального оптимума многомерной функции на основе предложенного метода.Досліджено мультиагентний підхід до оптимізації багатовимірних нелінійних функцій. Розроблено мультиагентний метод оптимізації з адаптивними параметрами. Проведено експерименти по пошуку глобального оптимуму багатовимірної функції на основі запропонованого методу.The approach to optimization of multidimensional nonlinear functions is investigated. The multiagent optimization method with adaptive parameters is developed. Experiments on search of global optimum of multidimensional function based on the offered method are made

Редукция баз нечётких правил на основе мультиагентного подхода

В статье рассмотрена актуальная задача отбора и преобразования баз нечётких правил, которые используются в экспертных системах. Для решения данной задачи предложен мультиагентный метод с непрямой связью между агентами, учитывающий взаимовлияние правил при прогнозировании. Проведены эксперименты по решению тестовых задач. Полученные результаты показали эффективность разработанного метода

Simplified modeling of the evolution of skills in a spatially resolved environment

We present a model for the spread, transmission and competition of skills with an emphasis on the role of spatial mobility of individuals. From a methodological point of view, we seek mathematical and computational simplicity in the sense of a minimal model. This minimalism lets us use a infinite dimensional simplex space and not a Euclidean space as underlying structure. Such a simplex captures the essentials of spatial heterogeneity without the mathematical difficulties of neighborhood structures. In the presented model, individuals may have no skill or either skill A or B. Individuals are born unskilled and may acquire skills by learning from a skilled individual. Skill A results in a small reproductive advantage and is easy to transmit (teaching happens at high rate), whereas skill B is harder to teach but results in a high benefit. The model exhibits a rich behavior; after an initial transient, the system settles to a fix point (constant distribution of skills), whereby the distribution of skills depends on a mobility parameter m. We observe different regimes, and as the main result, we conclude that for some settings of the system parameters, the spread of the (harder to learn but more beneficial) skill B is only possible within a specific range of the mobility parameter. From a technical point of view, this paper presents the application of the PRESS–method (probability reduced evolution of spatially resolved species) that enables the study of spatial effects in a very efficient manner. We analyze the consequences of spatial organization and argue that we can study aspects of social dynamics in an infinite dimensional simplex space. In spite of this maybe daunting name, the dynamics on such a structure is comparably easy to implement. The model we present is far from reflecting all the details of human interaction. On the contrary, we deliberately tailored the model to be as simple as possible from a mathematical point of view (but still reflecting central properties of spatial organization). This approach is guided by physics, where seemingly simple models which obviously don’t reflect the true physical behavior of a system (such as the Ising model) are nevertheless suited to reveal fundamental aspects and limiting cases of the real world

Selecting valued ecosystem components for cumulative effects in federally assessed road infrastructure projects in Canada

The concept of a ‘valued ecosystem component’ (VEC) was introduced in Canada in the early 1980s to bring focus to project-specific environmental assessment (EA), and its corollary, cumulative effects assessment (CEA). Despite the now central role of VECs in EA and that CEA practice has for years been plagued by poor practice reviews, surprisingly little research has been done in the past few decades to examine the principles, processes, and rationales applied to VEC selection in either assessment modality. Because VECs are at the heart of impact prediction, knowing more about how and why they are chosen and if they adequately represent cumulative effects (CEs) may help to reform CEA practice, and improve EA generally. Given this, the purpose of this thesis is to advance current understanding of VECs and VEC selection processes for CEs using comprehensive study EAs of major road transportation projects in Canada as a basis for the investigation. The research methodology adopts standard methods of qualitative inquiry. First, an in-depth review of literature since 1983 (when the term was introduced) was undertaken to examine VEC concept definitions and applications. Second, a document analysis of 11 comprehensive study reports (CSRs) and environmental impact statement (EISs) prepared for road construction projects was conducted. These CSRs represent the total number of road projects that triggered a comprehensive study since 1995, when CEA was introduced into the Canadian Environmental Assessment Act. Third, semi-structured interviews with 22 individuals directly involved in the road construction project EAs were conducted. Those interviewed include project proponents, federal responsible authorities, consultants, provincial government representatives, and Canadian Environmental Assessment Agency project managers. Data were gathered regarding the types of VECs typically selected in EA and CEA, VEC selection processes and actors, their values and rationales, and tools used to aid decision-making. Emphasis was also placed on examining process effectiveness and deficiencies. Significant findings include that science plays a very limited role in VEC selection for CEA, and overall, the CE VEC selection process is largely subjective rather than evidence-based. Further, CE VEC selection processes are strongly influenced by the initial set of VECs selected for the parent project. Most of the time, VEC lists for both project and CEA are exactly the same. Sometimes, a subset of project VECs are chosen to act as CE VECs using a deductive process called ‘residual effects analysis.’ CE VEC selection is not sensitive to ‘triple bottom line’ sustainability principles, and the level of public engagement in VEC selection decreases significantly at this stage of assessment. In the context of road construction EAs, the major challenges to CE VEC selection are (1) the ‘begin-again’ approach to each new project assessment, whereby there is very little knowledge transfer or capacity building from one assessment to another; (2) the linear nature of road development, which may compound experts’ evaluation of the local and regional importance of some ecological components and the decision to include them as CE VECs; and (3) the growth-inducing potentials of roads, which may result in high environmental risks to some (non-valued) components not anticipated during project VEC selection stage. Conversely, the major opportunities to improve CE VEC selection are: increasing public involvement; application of science to CE VEC selection processes; and early consideration of CEs at the scoping phase of the project assessment. The need for some form of VEC selection guidance in EA is clear, and transcends the road construction sector itself

Contributions to an anthropological approach to the cultural adaptation of migrant agents

This thesis proposes the use of Cultural Anthropology as a source of inspiration for solutions to the problem of adaptation of autonomous, intelligent, computational agents that migrate to societies of agents with distinctive features from the ones of the society where those agents were originally conceived. This has implications for interoperation of disparate Multi-Agent Systems. In particular, the cognitive approach to anthropology is argued to be a suitable theoretical foun-dation for this topic. Fieldwork practice in social anthropology is also indicated as an useful source of ideas. A pragmatic theory of intensionality is incorporated in this anthropological approach, resulting in a mechanism that allows agents to ascribe intensional ontologies of terms to societies that use unfamiliar means of communication; also, taxonomical relations among the terms in such ontologies can be retrieved, by means of a process inspired by the counterpart activity of ethnographers. This is presented using the Z notation for formal specification of systems, and illustrated on a set of terms from the game of cricket. Subsequently, a simulation of a game of cricket is described where one of the players is unfamiliar with the game, and therefore needs to learn the game by observing the other players. A reasonable behaviour for such a player is obtained, and the simulation offers grounds for further anthropologically-based studies. Further, a study of theories of moral sentiments is presented, and the Iterated Prisoner's Dilemma is used in simulations based on those ideas. The results of the simulations show clearly the positive impact, on groups of agents, of altruistic behaviour; this can only be coherently obtained in autonomous agents by modelling emotions, which are relevant for this project as anthropologists recognise them as an essential cross-cultural link. Finally, the consequences of this project to conceptions of Distributed Artificial Intelligence are discussed

Sourcing and outsourcing of materials and services in chemical supply chains

Ph.DDOCTOR OF PHILOSOPH