4,215 research outputs found
Improving System Design Through the Integration of Human Systems and Systems Engineering Models
The human is a critical aspect of many systems, but frequently there is a failure to properly account for human capabilities and involvement during system design. This inattention results in systems with higher lifecycle costs, decreased user compatibility, and the potential to produce disastrous consequences. This research presents an approach to integrating the human into system models by using two methods: static and dynamic modeling. The static method uses a user-centered design framework to create system- and human-centered models that deconstruct the system and user into their respective components. These models are integrated to create system models that include relevant information about the human and highlight potentially conflicting tasks. The dynamic method uses a human performance modeling tool to create a discrete event simulation (DES) of the system. This DES model is used to perform an analysis between system trades, by which constraints and assumptions placed on the human are verified. Data gained from the analysis are integrated back into system models in order to reflect true system performance. By applying these two integration methods early in the systemâs lifecycle, system models can more effectively account for the human as a critical component of the system, thus improving system design
Special Issue on the AMCIS 2001 Workshops: Integrating Enterprise Systems in the University Curriculum
The integration of Enterprise Systems into the curriculum of Business, Engineering, and Information Technology Faculties and Schools is a major challenge for many universities. Many interesting attributes are associated with this challenge: students generally have a strong interest to learn the subject and are often biased towards product-focused materials and skills; Enterprise Systems are comprehensive and particularly complex; and practical knowledge about Enterprise Systems is often lagging. This paper provides some structure to the Enterprise Systems education issue and will help academics distinguish among different approaches for the integration of these software packages into their curriculum. Various examples will assist beginners as well as experienced academics in evaluating their efforts. The ideas in this paper were presented in a special pre-conference workshop at the 2001 annual meeting of the Americas Conference on Information Systems (AMCIS) in Boston
Two-body non-leptonic decays on the lattice
We show that, under reasonable hypotheses, it is possible to study two-body
non-leptonic weak decays in numerical simulations of lattice QCD. By assuming
that final-state interactions are dominated by the nearby resonances and that
the couplings of the resonances to the final particles are smooth functions of
the external momenta, it is possible indeed to overcome the difficulties
imposed by the Maiani-Testa no-go theorem and to extract the weak decay
amplitudes, including their phases. Under the same assumptions, results can be
obtained also for time-like form factors and quasi-elastic processes.Comment: 15 pages, 1 Postscript figur
Human-Centered Design Using System Modeling Language
The human user is important to consider during system design. However, common system design models, such as the system modeling language, typically represent human users and operators as external actors, rather than as internal to the system. This research presents a method for integrating human considerations into system models through human-centered design. A specific system is selected to serve as the case study for demonstrating the methodology. The sample system is analyzed to identify the task and information flow. Then, both system- and human-centered diagrams are separately created to represent different viewpoints of the system. These diagrams are compared and analyzed, and new diagrams are created that incorporate both system and human considerations into one concordant representation of the system model. These new views allow systems engineers and human factors engineers to effectively communicate the role of the user during early system design trades
Understanding the Critical Ingredients for Facilitating Consumer Change in Housing First Programming: A Case Study Approach
Housing First is a form of permanent supportive housing for chronically homeless consumers with mental health and substance abuse issues. In light of the modelâs growing popularity and wide diffusion, researchers and policy makers have identified a need to better understand its critical ingredients and the processes through which they affect consumer outcomes. Researchers used a bottom-up approach to understand the critical ingredients of Housing First within community-based programs. Interviews and focus groups were conducted with 60 informants (staff and consumers) across 4 âsuccessfulâ Housing First programs. Qualitative analysis demonstrated six program ingredients to be essential: (1) a low-threshold admissions policy, (2) harm reduction, (3) eviction prevention, (4) reduced service requirements, (5) separation of housing and services, and (6) consumer education
Enkephalin systems in diencephalon and brainstem of the rat
The immunocytochemical distribution of [Leu]enkephalin and an adrenal enkephalin precursor fragment (BAM-22P) immunoreactivity was investigated in the diencephalon and brainstem of rats pretreated with relatively high doses of colchicine (300â400 Îg/10 Îl intracerebroventricularly). The higher ranges of colchicine pretreatment allowed the visualization of extensive enkephalin-containing systems in these brain regions, some of which are reported for the first time. Immunoreactive perikarya were found in many hypothalamic and thalamic nuclei, interpeduncular nucleus, substan-tia nigra, the colliculi, periaqueductal gray, parabrachial nuclei, trigeminal motor and spinal nuclei, nucleus raphe magnus and other raphe nuclei, nucleus reticularis paragigantocellularis, vestibular nuclei, several nor-adrenergic cell groups, nucleus tractus solitarius, as well as in the spinal cord dorsal horn. In addition to the above regions, immunoreactive fibers were also noted in the habenular nuclei, trigeminal sensory nuclei, locus coeruleus, motor facial nucleus, cochlear nuclei, dorsal motor nucleus of the vagus, and hypoglossal nucleus. When adjacent sections to those stained for [Leu]enkephalin were processed for BAM-22P immunoreactivity, it was found that these two immunoreactivities were distributed identically at almost all anatomical locations. B AM-22P immunoreactivity was generally less pronounced and was preferentially localized to neuronal perikarya. The results of the present as well as the preceding studies (Khachaturian et ai., '83) strongly suggest substantial structural similarity between the adrenal proenkephalin precursor and that which occurs in the brain. Also discussed are some differences and parallels between the distribution of [Leu]enkeph-alin and dynorphin immunoreactivities.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50020/1/902200305_ftp.pd
Time of origin of opioid peptide-containing neurons in the rat hypothalamus
By using a combined technique of immunocytochemistry and [ 3 H]thymidine autoradiography, we have determined the âbirth dateâ of opioid pep-tide-containing neurons in several hypothalamic nuclei and regions. These include proopiomelanocortin (POMC) neurons (represented by ACTH immunoreactivity) in the arcuate nucleus; dynorphin A neurons in the supraoptic and paraventricular nuclei and the lateral hypothalamic area; and leuenkephalin neurons in the periventricular, ventromedial, and medial mammillary nuclei, as well as in preoptic and perifornical areas. Arcuate POMC neurons were born very early in embryonic development, with peak heavy [ 3 H]thymidine nuclear labelling occurring on embryonic day E12. Supraoptic and paraventricular dynorphin A neurons were also labelled relatively early (peak at E13). The lateral hypothalamic dynorphin A neurons showed peak heavy labelling also on day E12, By contrast, leu-enkephalin neurons in the periventricular nucleus and medial preoptic area exhibited peak heavy nuclear labelling on day E14. Furthermore, perifornical and ventromedial leu-enkephalin neurons were also born relatively early (peak on days E12 and E13, respectively). However, the leu-enkephalin neurons in the medial mammillary nucleus were born the latest of all cell groups studied (i.e., peak at E15). The results indicate a differential genesis of these opioid peptide-containing neuronal groups in different hypothalamic nuclei and regions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50027/1/902360409_ftp.pd
Murine vaginal colonization model for investigating asymptomatic mucosal carriage of streptococcus pyogenes
While many virulence factors promoting Streptococcus pyogenes invasive disease have been described, specific streptococcal factors and host properties influencing asymptomatic mucosal carriage remain uncertain. To address the need for a refined model of prolonged S. pyogenes asymptomatic mucosal colonization, we have adapted a preestrogenized murine vaginal colonization model for S. pyogenes. In this model, derivatives of strains HSC5, SF370, JRS4, NZ131, and MEW123 established a reproducible, asymptomatic colonization of the vaginal mucosa over a period of typically 3 to 4 weeks' duration at a relatively high colonization efficiency. Prior treatment with estradiol prolonged streptococcal colonization and was associated with reduced inflammation in the colonized vaginal epithelium as well as a decreased leukocyte presence in vaginal fluid compared to the levels of inflammation and leukocyte presence in non-estradiol-treated control mice. The utility of our model for investigating S. pyogenes factors contributing to mucosal carriage was verified, as a mutant with a mutation in the transcriptional regulator catabolite control protein A (CcpA) demonstrated significant impairment in vaginal colonization. An assessment of in vivo transcriptional activity in the CcpA(â) strain for several known CcpA-regulated genes identified significantly elevated transcription of lactate oxidase (lctO) correlating with excessive generation of hydrogen peroxide to self-lethal levels. Deletion of lctO did not impair colonization, but deletion of lctO in a CcpA(â) strain prolonged carriage, exceeding even that of the wild-type strain. Thus, while LctO is not essential for vaginal colonization, its dysregulation is deleterious, highlighting the critical role of CcpA in promoting mucosal colonization. The vaginal colonization model should prove effective for future analyses of S. pyogenes mucosal colonization
Prediction & Model Evaluation for Space-Time Data
Evaluation metrics for prediction error, model selection and model averaging
on space-time data are understudied and poorly understood. The absence of
independent replication makes prediction ambiguous as a concept and renders
evaluation procedures developed for independent data inappropriate for most
space-time prediction problems. Motivated by air pollution data collected
during California wildfires in 2008, this manuscript attempts a formalization
of the true prediction error associated with spatial interpolation. We
investigate a variety of cross-validation (CV) procedures employing both
simulations and case studies to provide insight into the nature of the estimand
targeted by alternative data partition strategies. Consistent with recent best
practice, we find that location-based cross-validation is appropriate for
estimating spatial interpolation error as in our analysis of the California
wildfire data. Interestingly, commonly held notions of bias-variance trade-off
of CV fold size do not trivially apply to dependent data, and we recommend
leave-one-location-out (LOLO) CV as the preferred prediction error metric for
spatial interpolation.Comment: 15 pages, 5 figure
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