Exploring machine learning methods to automatically identify students in need of assistance

Copyright 2015 ACM. Methods for automatically identifying students in need of assistance have been studied for decades. Initially, the work was based on somewhat static factors such as students' educational background and results from various questionnaires, while more recently, constantly accumulating data such as progress with course assignments and behavior in lectures has gained attention. We contribute to this work with results on early detection of students in need of assistance, and provide a starting point for using machine learning techniques on naturally accumulating programming process data. When combining source code snapshot data that is recorded from students' programming process with machine learning methods, we are able to detect high- and low-performing students with high accuracy already after the very first week of an introductory programming course. Comparison of our results to the prominent methods for predicting students' performance using source code snapshot data is also provided. This early information on students' performance is beneficial from multiple viewpoints. Instructors can target their guidance to struggling students early on, and provide more challenging assignments for high-performing students. Moreover, students that perform poorly in the introductory programming course, but who nevertheless pass, can be monitored more closely in their future studies

Thermal Performance Evaluation of a Residential Solar/Gas Hybrid Water Heating System

In climate regions with lower average daily solar radiation, such as the Pacific Northwest, a solar energy collector might not economically satisfy year-round domestic water heating demands, requiring an auxiliary unit, such as a natural gas water heater. Previous studies of such hybrid systems have shown that the efficiencies achieved while running in combined solar/gas mode was lower than expected. This inefficiency was attributed to a reduction in gas burner efficiency when the process fluid was partially pre-heated by the solar input. To predict the actual energy and cost savings under various design conditions, the performance of solar/gas hybrid systems must be better understood. In this work, the performance of a commercial hybrid solar/gas system is experimentally characterized to evaluate individual component and overall system efficiency. The hybrid water heating system consisted of three flat plate collectors arranged in series (total area = 6.44 m2), and a 22.3 kW natural gas burner. Under different temperature lifts and solar insolation values, the system was operated at three different modes of heating: solar, gas, and combined solar/gas mode. Efficiency value for each mode was calculated. Based on the experimental efficiency results, a configuration that would provide higher efficiency for combined solar/gas heating is suggested

Cyber Collaboratory-based Sustainable Design Education: A Pedagogical Framework

Educators from across the educational spectrum are faced with challenges in delivering curricula that address sustainability issues. This article introduces a cyber-based interactive e-learning platform, entitled the Sustainable Product Development Collaboratory, which is focused on addressing this need. This collaboratory aims to educate a wide spectrum of learners in the concepts of sustainable design and manufacturing by demonstrating the effects of product design on supply chain costs and environmental impacts. In this paper, we discuss the overall conceptual framework of this collaboratory along with pedagogical and instructional methodologies related to collaboratory-based sustainable design education. Finally, a sample learning module is presented along with methods for assessment of student learning and experiences with the collaboratory

Integrating Sustainable Manufacturing Assessment into Decision Making for a Production Work Cell

Sustainability has been the focus of intense discussions over the past two decades, with topics surrounding the entire product life cycle. In the manufacturing phase, research has often focused solely on environmental impact assessment or environmental impact and cost analysis in its assessment of sustainability. Few efforts have investigated sustainable production decision making that addresses the three pillars of sustainability concurrently; which requires engineers and managers to consider economic, environmental, and social impacts. An approach is developed to assess broader sustainability impacts by conducting economic assessment, environmental impact assessment, and social impact assessment at the work cell level. Assessment results are then integrated into a sustainable manufacturing assessment framework, along with a modified weighting method based on pairwise comparison and an outranking decision-making method. The approach is illustrated for a representative machining work cell producing stainless steel knives. Economic, environmental, and social impact results are compared for three production scenarios by applying the sustainable manufacturing assessment framework. The case study finds that cutting tool cost is the largest contributor to production costs for the investigated work cell. The level of environmental and social impact varies according to cycle time. Sensitivity analysis is conducted to examine the robustness of the results.Keywords: Decision making, Sustainable manufacturing, Manufacturing work cell, Life cycle assessmen

Investigation of the combined efficiency of a solar/gas hybrid water heating system

In climate regions with large seasonal variations in solar radiation, such as the Pacific Northwest of the United States, a solar thermal energy collector might not economically satisfy year-round domestic water heating demands, requiring an auxiliary unit, such as a natural gas-fired water heater. Previous studies have shown that the burner efficiency of a gas-fired water heater varies depending on the log-mean temperature difference between the cold fluid (water) and the hot fluid (combustion gases). In a solar/gas hybrid water heating system, where solar collectors are used in conjunction with a gas-fired heater, the partial heating of water provided by solar input reduces the log-mean temperature difference value for the gas heater, reducing the efficiency of the gas burner. Since this efficiency reduction varies depending on the amount of pre-heating provided by solar energy input, it is difficult to accurately predict the actual cost and energy savings offered by solar/gas hybrid water heaters in different climates and operation scenarios. Hence, to predict the actual energy and cost savings under various design conditions, the performance of solar/gas hybrid systems must be better understood. The objective of this work is to experimentally determine the thermal performance of a solar/gas water hybrid water heating system with a 6.44 m2 flat plate solar collector array and a 22.3 kW natural gas burner in Corvallis, Oregon, USA. Under different temperature lifts and solar insolation values, the system was operated at three different modes of heating: solar, gas, and combined solar/gas mode. The overall system thermal efficiency value for each mode is calculated. The efficiency of the solar collector heating system was found to be 41.97%, 39.82%, and 35.05% at initial water temperature of 20, 30, and 51.5 °C, respectively. For initial water temperatures of 20, 30, and 51.5 °C, the efficiency of the gas burner was found to be 69.2%, 66.4%, and 65.5% at the HHV, and 76.7%, 73.6%, and 72.6% at the LHV of natural gas, respectively. In the combined solar/gas heating mode, the efficiency of the gas burner decreased with increasing solar fraction. For solar fractions of 4.93%, 9.40%, 11.39%, and 14.27%, the efficiency of the gas burner in terms of the HHV of natural gas was found to be of 69.08%, 66.80%, 66.17%, and 65.18%, respectively. Based on the experimental results, a configuration that would provide higher overall system efficiency for combined solar/gas heating is suggested

Dementia as a source of social disadvantage and exclusion

Objective To explore perceptions of the impacts of dementia on people living with the condition and those close to them and examine the relationship between dementia, disadvantage and social exclusion. Methods Semi-structured in-depth interviews were conducted with 111 participants: people with dementia (n = 19), carers (n = 28), health-care professionals (n = 21), social workers (n = 23) and service professionals (n = 20). NVivo 11 was used to code descriptions and identify impact areas. Results Participants described social, psychological, carer, material, service-based and disparity impacts associated with the experience of dementia. Some of these impacts correspond to social exclusion associated with age, but some are distinctive to dementia. Discussion It is argued that dementia generates its own forms of social disadvantage and exclusion. This is in addition to being subject to structural risk factors. The implications of the active effects of dementia as a social phenomenon should give rise to new policy and practice priorities.Peer reviewe

Awareness and practice of patient's rights law in Lithuania

BACKGROUND: Patient's rights law is intended to secure good medical practice, but it can also serve to improve understanding between patients and medical staff if both were aware of their rights. METHODS: Awareness and practice of the new patient's rights law in Lithuanian health care institutions was explored through a survey of 255 medical staff and 451 patients in the four Kaunas city medical units in 2002. Participation rates were 74% and 66%, respectively. RESULTS: Majority of the medical staff (85%) and little over one half of the patients (56%) had heard or read about the Law on Patient's Rights (p < 0.001). Only 50% of professionals compared to 69% of patients thought information for patients about diagnosis, treatment results and alternative treatments is necessary (p < 0.001). A clear discrepancy was indicated between physicians informing the patients (80% – 98% of physicians) and patients actually knowing (37% – 54%) their treatment prognosis, disease complications or possible alternative treatment methods. CONCLUSION: These results suggest a need for awareness-raising among patients to improve the practical implementation of the Patient's Rights Law in Lithuania

The Positive Relationship between Moderate-to-Vigorous Physical Activity and Bone Mineral Content Is Not Mediated by Free Leptin Index in Prepubertal Children: The PANIC Study.

PURPOSE: Moderate-to-vigorous physical activity (MVPA) positively influences bone mineral content (BMC) in prepubertal children, but it is unknown whether this relationship is partially mediated by free leptin index. The aim of this study was to examine whether the relationship between MVPA and total body less head (TBLH) BMC is mediated or moderated by free leptin index in prepubertal children. METHODS: We performed a cross-sectional analysis on 401 children (194 girls) from baseline examinations of the Physical Activity and Nutrition in Childhood Study. We applied the four-way decomposition mediation analysis method to assess whether free leptin index, measured from fasted blood samples, mediated the relationship between accelerometer-measured MVPA and TBLH BMC measured by dual-energy X-ray absorptiometry. RESULTS: MVPA had a positive controlled direct effect on TBLH BMC in girls and boys (β = 0.010 to 0.011, p 0.05). CONCLUSION: Our study indicates that MVPA positively influences TBLH BMC through pathways not related to free leptin index in predominantly normal-weight prepubertal children, likely primarily through mechanical loading. The relationships between MVPA, free leptin index and TBLH BMC may be influenced by other factors such as pubertal status and adiposity, so it is unknown whether these observations extend to overweight and obese children at different stages of puberty

The Positive Relationship between Moderate-to-Vigorous Physical Activity and Bone Mineral Content Is Not Mediated by Free Leptin Index in Prepubertal Children: The PANIC Study.

PurposeModerate-to-vigorous physical activity (MVPA) positively influences bone mineral content (BMC) in prepubertal children, but it is unknown whether this relationship is partially mediated by free leptin index. The aim of this study was to examine whether the relationship between MVPA and total body less head (TBLH) BMC is mediated or moderated by free leptin index in prepubertal children.MethodsWe performed a cross-sectional analysis on 401 children (194 girls) from baseline examinations of the Physical Activity and Nutrition in Childhood Study. We applied the four-way decomposition mediation analysis method to assess whether free leptin index, measured from fasted blood samples, mediated the relationship between accelerometer-measured MVPA and TBLH BMC measured by dual-energy X-ray absorptiometry.ResultsMVPA had a positive controlled direct effect on TBLH BMC in girls and boys (β = 0.010 to 0.011, p p > 0.05).ConclusionOur study indicates that MVPA positively influences TBLH BMC through pathways not related to free leptin index in predominantly normal-weight prepubertal children, likely primarily through mechanical loading. The relationships between MVPA, free leptin index and TBLH BMC may be influenced by other factors such as pubertal status and adiposity, so it is unknown whether these observations extend to overweight and obese children at different stages of puberty

Evaluating the use of zinc oxide and titanium dioxide nanoparticles in a metalworking fluid from a toxicological perspective

Adding nanoparticles (NPs) to metalworking fluids (MWFs) has been shown to improve performance in metal cutting. Zinc oxide nanoparticles (ZnO NPs) and titanium dioxide nanoparticles (TiO₂ NPs), for example, have exhibited the ability to improve lubricant performance, decrease the heat created by machining operations, reduce friction and wear, and enhance thermal conductivity. ZnO and TiO₂ NPs are also relatively inexpensive compared to many other NPs. Precautionary concerns of human health risks and environmental impacts, however, are especially important when adding NPs to MWFs. The goal of this research is to investigate the potential environmental and human health effects of these nanoenabled products during early design and development. This research builds on a prior investigation of the stability and toxicity characteristics of NPs used in metalworking nanofluids (MWnF™). The previous study only investigated one type of NP at one level of concentration. This research expands on the previous investigations through the valuation of three different types of NPs that vary in morphology (size and shape) and was conducted over a wide range of concentrations in the base fluid. In the presented work, mixtures of a microemulsion (TRIM® MicroSol® 585XT), two different types of TiO₂ NPs (referred to as TiO₂A and TiO₂B) and one type of ZnO NP were used to evaluate MWnF™ stability and toxicity. Dynamic light scattering (DLS) was used to assess stability over time and an embryonic zebrafish assay was used to assess toxicological impacts. The results reveal that, in general, the addition of these NPs increased toxicity relative to the NPfree formulation. The lowest rate of zebrafish malformations occurred at 5 g/L TiO₂A NP, which was even lower than for the base fluid. This result is particularly promising for future MWnF™ development, given that the mortality rate for 5 g/L TiO₂A was not significantly different than for the base fluid.Keywords: Environmental and health effects, Titanium Dioxide Nanoparticles, Zinc Oxide Nanoparticles, Nanotoxicology, Nanofluid Stabilit