1,822 research outputs found
Logistic Knowledge Tracing: A Constrained Framework for Learner Modeling
Adaptive learning technology solutions often use a learner model to trace
learning and make pedagogical decisions. The present research introduces a
formalized methodology for specifying learner models, Logistic Knowledge
Tracing (LKT), that consolidates many extant learner modeling methods. The
strength of LKT is the specification of a symbolic notation system for
alternative logistic regression models that is powerful enough to specify many
extant models in the literature and many new models. To demonstrate the
generality of LKT, we fit 12 models, some variants of well-known models and
some newly devised, to 6 learning technology datasets. The results indicated
that no single learner model was best in all cases, further justifying a broad
approach that considers multiple learner model features and the learning
context. The models presented here avoid student-level fixed parameters to
increase generalizability. We also introduce features to stand in for these
intercepts. We argue that to be maximally applicable, a learner model needs to
adapt to student differences, rather than needing to be pre-parameterized with
the level of each student's ability
Reduction and Summarization of Forage Production Data from Pasture and Range Lands
In an attempt to control and properly manage our vast pasture and range lands there have been many problems that the scientist has been confronted with. Among these has been the problem of reducing the great quantity of collected data from the ranges and pasture lands into a form suitable for scientific analysis. In the past this reduction process has been accomplished by slow, painstaking hand calculation methods, thus making it virtually impossible for the scientist to analyze and propose corrective measures at the time they are needed. However, with the advent of high speed computing equipment this need no longer be a major factor of concern to the research worker today. It has been the purpose of this study to develop a program utilizing computers to solve one of these many problems. The problem that has been specifically dealt with in this report is that of the summarization of forage weight production data
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Intelligent modelling of bioprocesses: A comparison of structured and unstructured approaches
This contribution moves in the direction of answering some general questions about the most effective and useful ways of modelling bioprocesses. We investigate the characteristics of models that are good at extrapolating. We trained 3 fully predictive models with different representational structures (diff eqns, inheritance of rates, network of reactions) on Saccharopolyspora erythraea shake flask fermentation data using genetic programming. The models were then tested on unseen data outside the range of the training data and the resulting performances compared. It was found that constrained models with mathematical forms analogous to internal mass balancing and stoichiometric were superior to flexible unconstrained models even though no A priori knowledge of this fermentation was used
13.4.18. Chufa Biology and Management
Chufa (Cyperus esculentus) is an emergent perennial sedge that is common in seasonally flooded wetlands. Although chufa is common in many States, it is most abundant in the Southeast, including the Mississippi alluvial valley (Fig. 1). Belowground biomass of chufa, especially the tubers, serves as a valuable food source for waterfowl and cranes. Chufa tubers rank tenth among the most important waterfowl foods in the United States
13.4.18. Chufa Biology and Management
Chufa (Cyperus esculentus) is an emergent perennial sedge that is common in seasonally flooded wetlands. Although chufa is common in many States, it is most abundant in the Southeast, including the Mississippi alluvial valley (Fig. 1). Belowground biomass of chufa, especially the tubers, serves as a valuable food source for waterfowl and cranes. Chufa tubers rank tenth among the most important waterfowl foods in the United States
TB18: Mensuration Methods for Site Classification of Shade Tolerant Tree Species
All of the climax tree species in Maine are shade tolerant. This means that they have the capacity of surviving and growing slowly in the seedling, sapling and pole-size stages. As a result none of the established methods employing total age are applicable. In searching for a way to overcome this problem an entirely new approach to quantitative site evaluation was conceived. This study evaluates this new mensurational approach to site evaluation for shade-tolerant trees.https://digitalcommons.library.umaine.edu/aes_techbulletin/1178/thumbnail.jp
Reconstructing the Holocene glacial history of northern Troms and western Finnmark, Arctic Norway
\ua9 2024 The Author(s). Boreas published by John Wiley & Sons Ltd on behalf of The Boreas Collegium. Here we present the first Lateglacial and Holocene glacial history from Rotsunddalen, northern Troms and western Finnmark county, northern Norway, based on both relative and numerical moraine dating using Schmidt hammer, soil chronosequencing and terrestrial cosmogenic nuclide dating. We combine these chronological data with a regional map of the glacial geomorphology to hypothesize key events in the glacial history from around 14 ka to present. Our reconstruction shows that, following deglaciation of the main ice sheet across central Troms and Finnmark, mountain glaciers were terminating on land, close to the coast, between around 12.1 and 10.6 ka. Continued recession of the main Fennoscandian Ice Sheet margin towards the SE led to the isolation of several large plateau icefields and outlet glaciers that generated moraines at around 10.2–9.2 ka, which we ascribe to the Erdalen Event, and 8.4–8.2 ka, which is broadly contemporaneous with the 8.2 ka cold event. Although the latter corresponds with the Scandinavian Finse Event, very few moraines have been dated to this time and we therefore view it as a tentative hypothesis for future work to test. During the Holocene Thermal Maximum (~6.6 to 6.3 ka) most (if not all) glaciers in the region disappeared, but then regrew during the Neoglaciation and produced large moraines dated to around 4.7 ka that lie a few hundred metres distal to the prominent Little Ice Age moraines (previously dated to AD 1810s–1870s). Given the limitations of our dating approach, the preservation of moraines dated to this period in northern Norway also warrants further investigation. We also highlight that terrestrial cosmogenic nuclide dating of the moraines is not consistent with other dating approaches and the widely established deglaciation history of the region, probably owing to cosmogenic inheritance and insufficient glacial erosion
Increases in efficiency and enhancements to the Mars Observer non-stored commanding process
The Mars Observer team was, until the untimely loss of the spacecraft on August 21, 1993, performing flight operations with greater efficiency and speed than any previous JPL mission of its size. This level of through-put was made possible by a mission operations system which was composed of skilled personnel using sophisticated sequencing and commanding tools. During cruise flight operations, however, it was realized by the project that this commanding level was not going to be sufficient to support the activities planned for mapping operations. The project had committed to providing the science instrument principle investigators with a much higher level of commanding during mapping. Thus, the project began taking steps to enhance the capabilities of the flight team. One mechanism used by project management was a tool available from total quality management (TQM). This tool is known as a process action team (PAT). The Mars Observer PAT was tasked to increase the capacity of the flight team's nonstored commanding process by fifty percent with no increase in staffing and a minimal increase in risk. The outcome of this effort was, in fact, to increase the capacity by a factor of 2.5 rather than the desired fifty percent and actually reduce risk. The majority of these improvements came from the automation of the existing command process. These results required very few changes to the existing mission operations system. Rather, the PAT was able to take advantage of automation capabilities inherent in the existing system and make changes to the existing flight team procedures
Critical Issues: Defining and Debunking Misconceptions in Health, Education, Criminal Justice, and Social Work/Social Services
The University of Houston Downtown Committee for the Journal of Family Strengths introduces Volume 18, Issue 1: Critical Issues: Defining and Debunking Misconceptions in Health, Education, Criminal Justice, and Social Work/Social Services
Effect of In-Plane Voiding on the Fracture Behavior of Laser Sintered Polyamide
The primary contributors to poor mechanical properties in polyamide materials used during Selective
Laser Sintering® are qualified. Methods to quantify the decreased mechanical properties, including
Scanning Electron Microscopy (SEM) of fracture surfaces, are compared against each other and against
mechanical properties of components fabricated using multiple process parameters. Of primary interest
are Ultimate Tensile Strength (UTS) and Elongation at Break (EOB) of tensile specimens fabricated
under conditions that produce varying degrees of ductile and brittle fracture.Mechanical Engineerin
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