Explaining Simulations Through Self Explaining Agents

Several strategies are used to explain emergent interaction patterns in agent-based simulations. A distinction can be made between simulations in which the agents just behave in a reactive way, and simulations involving agents with also pro-active (goal-directed) behavior. Pro-active behavior is more variable and harder to predict than reactive behavior, and therefore it might be harder to explain. However, the approach presented in this paper tries to make advantage of the agents' pro-activeness by using it to explain their behavior. The aggregation of the agents' explanations form a basis for explaining the simulation as a whole. In this paper, an agent model that is able to generate (pro-active) behavior and explanations about that behavior is introduced, and the implementation of the model is discussed. Examples show how the link between behavior generation and explanation in the model can contribute to the explanation of a simulation.Explanation, Agents, Goal-Based Behavior, Virtual Training

Wave-particle duality: A proposed resolution

There are several integration problems of fundamental physics that still lack coherent solutions, the case in point being wave-particle duality. While empiricism and mathematical modelling have served physics well, they have not yet been able to achieve integrated causal models. Conventional theories and approaches have only provided partial solutions, and it is possible that a more radical reconceptualisation of fundamental physics may be required. This work comes at the issue from a totally different approach: it applies design thinking to the problem. The result is the cordus conjecture, which proposes that the photon, and indeed every matter ‘particle’, has an internal structure comprising a 'cordus': two reactive ends that each behave like a particle, with a fibril joining them. The reactive ends are proposed to be a small finite distance apart, and energised [typically in turn] at a frequency. When energised they emit a transient force pulse along a line called a hyperfine fibril [hyff], and this makes up the field. This concept is used to explain the path dilemmas of the single photon in the double-slit device, and the wave behaviour of light including the formation of fringes by single photons and beams of light. In addition it provides a tangible explanation for frequency. It also yields new quantitative derivations for several basic optical effects: critical angle, Snell’s law, and Brewster’s angle. Thus the cordus structure offers an alternative conceptual explanation for wave-particle duality

CAN WE LEGISLATE FOR PREVENTION AND EARLY INTERVENTION SERVICES FOR CHILDREN? AN ANALYSIS OF ASPECTS OF THE 2002 DRAFT CHILDREN’S BILL

This article provides an explanation and critical analysis of the prevention and early intervention provisions in the South African Law Commission ‘s 2002 Draft Children’s Bill. In addition, the inter-sectoral approach provided for in the Draft Bill and the proposed national policy framework are evaluated. Innovative recommendations that would allow child and family courts to issue early intervention orders are discussed. It is contended in the article that if the prevention and early intervention provisions in the Draft Bill were to be translated into legislation, this could produce significant consequences. It would cause a fundamental shift in balance between proactive and reactive social work services for children in South Africa

ACUTE NITRATE EXPOSURE CAUSES PROTEOMIC CHANGES CONSISTENT WITH THE REGULATION OF REACTIVE OXYGEN AND NITROGEN SPECIES

Nitrate is the most common ionic form of nitrogen in aquatic ecosystems. Although nitrate is known to affect ecosystems at high levels through eutrophication, hypoxia and loss of biodiversity, it is considered to be physiologically inert to the individual aquatic organism. To test the physiological effects of nitrate on aquatic life, we exposed gill tissue of the Pacific oyster, Crassostrea gigas, to nitrate and characterized changes in protein expression, using a gel-based proteomics approach. Of the 642 protein spots detected, we found that 24 proteins (15 identified) changed expression in response to a 6-hour exposure to nitrate concentrations ranging from 0-73 mg/L, values that characterize highly contaminated surface and ground waters. Proteins changing expression included the oxidative stress proteins thioredoxin and cavortin (a member of the superoxide dismutase family) as well as proteins that are involved in G-protein signaling (Rho-GDI, ADP-ribosylation factor, G-protein ß-subunit), protein homeostasis (heat shock protein 70, prohibitin, calreticulin, and proteasome &#;-type 4 subunit), glycolysis (enolase), transport of hydrophobic molecules (lipocalin) and cytoskeletal arrangements (intermediate filaments and a gelsolin-like adseverin). The most parsimonious explanation for these changes in protein expression assumes that C. gigas reduces nitrate to nitrite and nitric oxide, which reacts with superoxide anions to form the very reactive peroxynitrite. We propose that part of the cellular response to reactive nitrogen species,phagocytic hemocytes inhibit the production of reactive oxygen species, potentially compromising the immune response of oysters to invading pathogens