A model for dynamic allocation of human attention among multiple tasks

The problem of multi-task attention allocation with special reference to aircraft piloting is discussed with the experimental paradigm used to characterize this situation and the experimental results obtained in the first phase of the research. A qualitative description of an approach to mathematical modeling, and some results obtained with it are also presented to indicate what aspects of the model are most promising. Two appendices are given which (1) discuss the model in relation to graph theory and optimization and (2) specify the optimization algorithm of the model

Modeling human decision making behavior in supervisory control

An optimal decision control model was developed, which is based primarily on a dynamic programming algorithm which looks at all the available task possibilities, charts an optimal trajectory, and commits itself to do the first step (i.e., follow the optimal trajectory during the next time period), and then iterates the calculation. A Bayesian estimator was included which estimates the tasks which might occur in the immediate future and provides this information to the dynamic programming routine. Preliminary trials comparing the human subject's performance to that of the optimal model show a great similarity, but indicate that the human skips certain movements which require quick change in strategy

Assessment of antibacterial activity of different treatment modalities in deciduous teeth: an in vitro study

In recent years, different biotechnological materials and modalities with antibacterial activity are being developed for oral cavity disinfection. However, the antimicrobial effects of all these materials have not been studied and understood in detail. Thus, the aim of this study was to compare the antibacterial activity of ozone therapy with dentine-bonding agents (containing antibacterial monomer 12-meth-acryloyloxydodecylpyridinium bromide (MDPB) and 10-methacryloyloxydecyl dihydrogen phosphate (MDP) and Ca(OH)(2) for deciduous teeth in vitro. The antibacterial effectiveness of the studied materials was determined by using a tooth cavity model on cylindrical cavities created in 90 deciduous second mandibular molars. Streptococcus mutans suspension was inoculated in the cavities. The teeth were distributed into six study groups (five different modalities and a negative control group). Dentine samples, which were collected from the cavities before and after the treatment sessions, were microbiologically evaluated and the materials' antibacterial activities were compared. There were statistically significiant differences in the S. mutans counts before and after treatment (P < 0.05). In terms of antibacterial efficiency, 60-second O-3 treatment was found to be the most successful method, followed by 30-second O-3, Clearfil Protect Bond (containing MDPB), Clearfil SE Bond (containing MDP) and Ca(OH)(2) treatment. The results from this study suggested that longer exposure to ozone might have more beneficial effects in terms of antibacterial activity for reducing the levels of S.mutans

Developing Operator Models for UAV Search Scheduling

With the increased use of Unmanned Aerial Vehicles (UAVs), it is envisioned that UAV operators will become high level mission supervisors, responsible for information management and task planning. In the context of search missions, operators supervising a large number of UAVs can become overwhelmed with the sheer amount of information collected by the UAVs, making it difficult to optimize the information collection or direct their attention to the relevant data. Novel decisionsupport methods that account for realistic operator performance will therefore be required to aid the operators. This paper considers a decision support formulation for sequential search tasks, and discusses a non-preemptive scheduling formulation for a single operator performing a search mission in a time-constrained environment. The formulation is then generalized to include operator performance obtained from previous human-in-the-loop experiments, and presents one of the principal contributions of the paper. The sensitivity of the proposed model is analyzed in the presence of uncertainty to the operator model and search times, and a comparison is made between the expected performance difference between this scheduling system and a greedy scheduling strategy representative of operator planning. The paper concludes with the design of a human-in-the-loop experiment for a scheduling, replanning task for a simulated UAV mission.Aerospace Engineerin