A knowledge-based decision support system for payload scheduling

This paper presents the development of a prototype Knowledge-based Decision Support System, currently under development, for scheduling payloads/experiments on space station missions. The DSS is being built on Symbolics, a Lisp machine, using KEE, a commercial knowledge engineering tool

Value of time, schedule delay and reliability - estimates based on choice behaviour of Dutch commuters facing congestion

This paper presents the results of a large stated choice experiment among Dutch commuters facing congestion. The experiment consisted of a fractional factorial design with 15 different attributes, three alternatives were car specific and the other was always public transport. Various model specifications have been estimated on the collected choice data allowing us to analyse choice behaviour of road users and determine their values of time, schedule delay (both late and early) and reliability (or uncertainty). In this paper we present the estimates of the best-fitting discrete choice models and interpret the results.

A study of microwave downcoverters operating in the K sub u band

A computer program for parametric amplifier design is developed with special emphasis on practical design considerations for microwave integrated circuit degenerate amplifiers. Precision measurement techniques are developed to obtain a more realistic varactor equivalent circuit. The existing theory of a parametric amplifier is modified to include the equivalent circuit, and microwave properties, such as loss characteristics and circuit discontinuities are investigated

The relationships between illness perceptions, social support, coping on mood after first-time myocardial infarction

The aim of this study was to examine how illness perceptions, social support, and coping influence first-time MI patients' moods after six months post-MI. The second aim was to examine the roles of first-time MI couples' illness perceptions on their own moods. One hundred and twenty six first-time MI patients filled in the questionnaires during their hospitalisation, and 91 of them completed all three assessments during the first six months. Data from 42 first-time MI couples were also collected during the patients' hospitalisation. Thirty-five of the 42 MI couples completed all three assessments during the first six months. Therefore, information from 91 MI patients and 35 MI couples were used for longitudinal data analyses. The results indicated that when comparing with healthy people, first-time MI patients reported higher levels of depression, state anxiety and negative affect. Those held negative illness perceptions (e.g., worse illness consequences, longer recovery time, and worse symptom perception) tended to feel more depressed or anxious. Hierarchical regressions indicated that symptom perception and illness consequence perception were two important contributors of these MI patients' moods. In addition, some types of coping strategies and mood variables were also important. Data of MI couples indicated that spouses were also influenced by the MI event, and they reported higher levels of depression, state anxiety and negative affect. Those couples who both had negative illness perceptions of the MI tended to feel more negative. However, couples' moods did not significant correlate with each other. Hierarchical regression further showed only their own illness perceptions and moods significantly contributed to their own moods. Their partners' illness perceptions and moods did not contribute to their own moods. The finding suggested illness perceptions played important roles on MI patients' and spouses' moods. To improve moods, future studies should focus more on interventions of illness perceptions

LISP based simulation generators for modeling complex space processes

The development of a simulation assistant for modeling discrete event processes is presented. Included are an overview of the system, a description of the simulation generators, and a sample process generated using the simulation assistant

Neutron spin-echo study of the critical dynamics of spin-5/2 antiferromagnets in two and three dimensions

We report a neutron spin-echo study of the critical dynamics in the $S=5/2$ antiferromagnets MnF$_2$ and Rb$_2$MnF$_4$ with three-dimensional (3D) and two-dimensional (2D) spin systems, respectively, in zero external field. Both compounds are Heisenberg antiferromagnets with a small uniaxial anisotropy resulting from dipolar spin-spin interactions, which leads to a crossover in the critical dynamics close to the N\'eel temperature, $T_N$. By taking advantage of the $\mu\text{eV}$ energy resolution of the spin-echo spectrometer, we have determined the dynamical critical exponents $z$ for both longitudinal and transverse fluctuations. In MnF$_2$, both the characteristic temperature for crossover from 3D Heisenberg to 3D Ising behavior and the exponents $z$ in both regimes are consistent with predictions from the dynamical scaling theory. The amplitude ratio of longitudinal and transverse fluctuations also agrees with predictions. In Rb$_2$MnF$_4$, the critical dynamics crosses over from the expected 2D Heisenberg behavior for $T\gg T_N$ to a scaling regime with exponent $z = 1.387(4)$, which has not been predicted by theory and may indicate the influence of long-range dipolar interactions

Structure and Reactivity Studies of Bis(pyridylimino)isoindolate Transition Metal Complexes.

In this dissertation, transition metal complexes supported by bpi-type (bpi = 1,3-bis(2’-pyridylimino)isoindolate) ligands were designed and synthesized to study their activity, selectivity, and stability in hydrogenation and dehydrogenation reactions and to determine the role of the bpi ligand in these transformations. A new family of ruthenium bpi complexes capable of catalyzing promoterless and chemoselective dehydrogenation of alcohols and amines with liberation of dihydrogen were developed. In particular, the bis(phosphine) ruthenium bMepi hydride (bMepi = 1,3-bis(6’-methyl-2’-pyridylimino)isoindolate) system mediates dehydrogenation of secondary alcohols to ketones, dehydrogenative coupling of primary alcohols to esters, and double dehydrogenation of primary amines to nitriles with high conversion efficiency. An unusual feature of this catalyst system is the high selectivity for secondary alcohol dehydrogenation in the presence of primary alcohols. By avoiding the use of hazardous reagents and harsh oxidants, these dehydrogenative transformations provide environmentally benign methodologies for fine and commodity chemical synthesis with high atom economy. Furthermore, to understand the relationship between catalyst structure and reactivity, the catalytic mechanism of acceptorless alcohol dehydrogenation was elucidated by a series of kinetic and isotopic labeling studies, isolation of intermediates, and evaluation of new ligand variants. The new chemical knowledge acquired in the mechanistic investigation was applied to conceptualize and develop three new projects: (1) iron bMepi systems that feature control over catalytic alkene hydroboration activity and regioselectivity by remote site modifications, (2) ruthenium bpi complexes capable of upgrading ethanol to 1-butanol with state-of-the-art activity (53% conversion and 265 turnovers per hour), and (3) a new series of multifunctional ruthenium complexes with appended Lewis acidic borane sites for studying how Lewis acidity influences the reactivity of the ruthenium hydride moiety and biases the system for stereoselective semi-hydrogenation of alkynes. Collectively, the studies presented in this dissertation demonstrate the new development of highly active and chemoselective catalysts capable of promoting challenging dehydrogenation reactions and showcase how precise structural, electronic, and cooperative interactions in the secondary coordination environment can be used to regulate metal-based catalysis.PhDChemistryUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/120813/1/kueinin_1.pd