Communicating optimization results

Thesis (M. Eng. in Logistics)--Massachusetts Institute of Technology, Engineering Systems Division, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (p. 76-79).With global supply chains becoming increasingly complex, leading companies are embracing optimization software tools to help them structure and coordinate their supply chains. With an array of choices available, many organizations opt for one of the numerous off-the-shelf products. Others choose instead to create their own bespoke optimization tools. While this custom approach affords greater versatility than a commercially available product, it also presents significant challenges to both the creators and users of the tool in terms of complexity. It can often be time-consuming and difficult for the users of the tool to understand and verify the results that are generated. If a decision-maker has difficulty understanding or trusting the output of a model, then the value of the tool is seriously diminished. This paper examines the challenges between the creators, or operational research engineers, and the end-users when deploying and executing complex optimization software in supply chain management. We examine the field of optimization modeling, communication methods involved, and relevant data visualization techniques. Then, we survey a group of users from our sponsoring company to gain insight to their experience using their tool. The general responses and associated crosstab analysis reveals that training and visualization are areas that have potential to improve the user's understanding of the tool, which in turn would lead to better communication between the end-users and the experts who build and maintain the tool. Finally, we present a section on current, cutting edge visualization techniques that can be adapted to influence the way a user visualizes the optimization results.by Drake Bailey and Daniel Skempton.M.Eng.in Logistic

Viscoelastic Characterization of Vapor-Grown Carbon Nanofiber/Vinyl Ester Nanocomposites using a Response Surface Methodology

The effects of vapor-grown carbon nanofiber (VGCNF) weight fraction, applied stress, and temperature on the viscoelastic responses (creep strain, creep rate, and creep compliance) of VGCNF/vinyl ester (VE) nanocomposites were studied using a central composite design (CCD). The nanocomposite test articles were fabricated by high shear mixing, casting, curing, and post-curing in an open face mold under a nitrogen environment. Short-term creep/creep recovery experiments were conducted at prescribed combinations of temperatures (23.8 – 69.2 C), applied stresses (30.2 – 49.8 MPa), and VGCNF weight fractions (0.00 – 1.00 parts of VGCNF per hundred parts of resin, phr) determined from the CCD. The response surface models (RSMs) for predicting these viscoelastic responses were developed using the least squares method and an analysis of variance procedure. The response surface estimates indicate that increasing the VGCNF weight fraction decreases the creep resistance of the VGCNF/VE nanocomposites at high temperatures (46.5 – 69.2 C)

Physiology of the thermophilic acetogen Moorella thermoacetica

Moorella thermoacetica (originally isolated as Clostridium thermoaceticum) has served as the primary acetogenic bacterium for the resolution of the acetyl coenzyme A (acetyl-CoA) orWood–Ljungdahl pathway, a metabolic pathway that (i) autotrophically assimilates CO2 and (ii) is centrally important to the turnover of carbon in many habitats. The purpose of this article is to highlight the diverse physiological features of this model acetogen and to examine some of the consequences of its metabolic capabilities

A Brief Review of Modern Uses of Scattering Techniques

Thomson, Rayleigh, Mie, and Raman scattering are commonly used in several disciplines in science and engineering. The techniques involve the scattering of electromagnetic radiation or particles in a sample. This paper provides a brief history for each scattering method, describes the traditional laboratory approach for implementation, and discusses current uses and variations of these four techniques

Physiology of the thermophilic acetogen Moorella thermoacetica

Moorella thermoacetica (originally isolated as Clostridium thermoaceticum) has served as the primary acetogenic bacterium for the resolution of the acetyl coenzyme A (acetyl-CoA) orWood–Ljungdahl pathway, a metabolic pathway that (i) autotrophically assimilates CO2 and (ii) is centrally important to the turnover of carbon in many habitats. The purpose of this article is to highlight the diverse physiological features of this model acetogen and to examine some of the consequences of its metabolic capabilities

Group-Based Participatory Arts Interventions Validate Personhood for those Living with Dementia

Participatory arts-based interventions for people living with dementia involve the collaborative creation and performance of poetry, story, song, dance, and visual arts. These programs are designed to support self-expression and productive collaboration among people living with dementia while stimulating positive social interactions and feelings of empowerment and validation. In this commentary, we explore the use and potential benefits of validation in the implementation of person-centered participatory arts interventions in the context of dementia care. We offer a novel framework for understanding validation as a common intervention method during these activities, organized into five themes: collaboration, connection, communication, creation, and confirmation. These validation opportunities are suggested to offer direct benefits for participants as well as indirect benefits when modeled in the presence of formal care providers and family members. Clinicians and other transdisciplinary care providers are encouraged to understand, use, and teach these and other validation-focused arts interventions with persons living with dementia

Parent-Offspring Resource Allocation in Domestic Pigs

Behavioural research on domestic pigs has included parent-offspring conflict, sibling competition, and the use of signals which influence resource allocation. In this paper, we review key sow-piglet behavioural studies and discuss their relevance to resource allocation theory. Sibling competition begins in the uterus and continues after birth, as piglets compete directly for access to the sow\u27s teats. This competition is made more severe by a unique dentition, which newborn piglets use to lacerate the faces of siblings during teat disputes. Competition often leads to the death of some littermates, especially those of low birth weight. Piglets also compete indirectly for milk, apparently by stimulating milk production at the teats that they habitually use at the expense of milk production by other teats. The complex nursing behavior of the sow appears designed to prevent the more vigorous piglets from monopolizing the milk. Sows give vocal signals which both attract piglets to suckle and synchronize their behavior during nursing episodes. Piglets give loud vocal signals when separated from the sow; calls which vary in intensity and appear to be honest signals of need. Udder massage by piglets may also serve as an honest signal of need. Parent-offspring conflict has been demonstrated experimentally in pigs. Specifically, when given the opportunity to control contact with their piglets, sows nurse less frequently, provide less milk, and lose less weight during lactation than sows that cannot control their level of contact. Because of this interesting natural history and because they are so amenable to experimentation, domestic pigs provide a rich system for testing ideas drawn from resource allocation theory

Oscillatory Motor Network Activity During Rest and Movement: An fNIRS Study

Coherent network oscillations (\u3c0.1 Hz) linking distributed brain regions are commonly observed in the brain during both rest and task conditions. What oscillatory network exists and how network oscillations change in connectivity strength, frequency and direction when going from rest to explicit task are topics of recent inquiry. Here, we study network oscillations within the sensorimotor regions of able-bodied individuals using hemodynamic activity as measured by functional near-infrared spectroscopy (fNIRS). Using spectral interdependency methods, we examined how the supplementary motor area (SMA), the left premotor cortex (LPMC) and the left primary motor cortex (LM1) are bound as a network during extended resting state (RS) and between-tasks resting state (btRS), and how the activity of the network changes as participants execute left, right, and bilateral hand (LH, RH, and BH) finger movements. We found: (i) power, coherence and Granger causality (GC) spectra had significant peaks within the frequency band (0.01–0.04 Hz) during RS whereas the peaks shifted to a bit higher frequency range (0.04–0.08 Hz) during btRS and finger movement tasks, (ii) there was significant bidirectional connectivity between all the nodes during RS and unidirectional connectivity from the LM1 to SMA and LM1 to LPMC during btRS, and (iii) the connections from SMA to LM1 and from LPMC to LM1 were significantly modulated in LH, RH, and BH finger movements relative to btRS. The unidirectional connectivity from SMA to LM1 just before the actual task changed to the bidirectional connectivity during LH and BH finger movement. The uni-directionality could be associated with movement suppression and the bi-directionality with preparation, sensorimotor update and controlled execution. These results underscore that fNIRS is an effective tool for monitoring spectral signatures of brain activity, which may serve as an important precursor before monitoring the recovery progress following brain injury

Oxalate metabolism by the acetogenic bacterium Moorella thermoacetica

Whole-cell and cell-extract experiments were performed to study the mechanism of oxalate metabolism in the acetogenic bacterium Moorella thermoacetica. In short-term, whole-cell assays, oxalate consumption was low unless cell suspensions were supplemented with CO2, KNO3, or Na2S2O3. Cell extracts catalyzed the oxalate-dependent reduction of benzyl viologen. Oxalate consumption occurred concomitant to benzyl viologen reduction; when benzyl viologen was omitted, oxalate was not appreciably consumed. Based on benzyl viologen reduction, specific activities of extracts averaged 0.6 μmol oxalate oxidized min−1 mg protein−1. Extracts also catalyzed the formate-dependent reduction of NADP+; however, oxalate-dependent reduction of NADP+ was negligible. Oxalate- or formate-dependent reduction of NAD+ was not observed. Addition of coenzyme A (CoA), acetyl-CoA, or succinyl-CoA to the assay had a minimal effect on the oxalate-dependent reduction of benzyl viologen. These results suggest that oxalate metabolism by M. thermoacetica requires a utilizable electron acceptor and that CoA-level intermediates are not involved