Non-homogenous Groups Research Articles

Effect of Students’ Activities on Academic Performance Using Clustering Evolution Analysis

Educational data mining is a technique to evaluate educational process of university students, especially in their early stages. Most preliminary studies focus on observing courses undertaken by students from one semester to the next to predict their success rate. However, besides studying, many students are also involved in non-academic activities, which tends to affect their grades. Therefore, the research aims to determine the effect of student activities on grades while taking into account their academic activities. The method used for clustering is K-Means. Data are collected by observing students’ activity patterns in lectures. The research is conducted in two study programs at Petra Christian University: Business Management and Architecture. The results show that the K-Means method gives good results. The clusters formed from the data show non-homogenous groups and produce insights from several groups. The results show a tendency for students’ performance to increase along with the number of activities and points earned. Most students have increased activities during busy times in the third, fourth, fifth, and sixth semesters. The peak is between the fifth and sixth semesters. Then, it starts to decrease in the seventh and eighth semesters. Therefore, students’ activities in the Business Management study program affect performance significantly. Meanwhile, in the Architecture study program, it has an insignificant effect on performance.

The surprises in optical coherence tomography (OCT) findings in patients presenting with in-stent restenosis: the road less travelled

Abstract Funding Acknowledgements Type of funding sources: None. Background Morphological features of neointimal tissue play a pivotal role in the pathophysiology of In-Stent Restenosis (ISR) after percutaneous coronary intervention, hence understanding these features and patterns is crucial. Purpose The present study was designed to qualitatively and quantitatively assess neointimal characteristics of lesions using OCT in patients presenting with ISR. Methods This was a single-center, prospective, observational study performed between 1st August 2020 and 30th December 2021 at a tertiary-care center in India. Patients diagnosed with stable angina and acute coronary syndrome with post-procedural angiographically documented restenosis (>50%) were included. Qualitative and quantitative assessment of neointimal hyperplasia patterns was performed using OCT. Results A total of 34 patients with ISR were studied. Neointimal hyperplasia was classified as (i) homogenous group (n=18) and (ii) non-homogenous group (n=16). As many as 14 (77.8%) diabetics belonged to the homogenous group. Predominant plaque characteristics such as neoatherosclerosis, cholesterol crystals, and calcium were documented in 14 (77.8%), 12 (66.7%), and 11 (61.1%) patients in the homogenous group and in 10 (62.5%), 10 (62.5%), and 9 (56.2%) patients in the non-homogenous group, respectively. Unexpanded stent struts were identified in 11 (61.1%) and 11 (68.8%) patients in the homogenous and non-homogenous groups, respectively. Mean strut thickness was 93.73 ± 31.03 µm and 83.54 ± 18.0 µm, ISR was 72.50 ± 15.93% and 65.37 ± 21.69%, the neointimal thickness was 588.06 ± 167.82 mm and 666.25 ± 218.05 mm, and neointimal hyperplasia was 54.54 ± 11.23% and 59.26 ± 8.86% in the homogenous and non-homogenous groups, respectively. Conclusion Neoatherosclerosis and stent underexpansion was predominantly observed in our study, which was in contrast to most of the existing literature [1,2,3], and only diabetes was found to be significantly associated with homogenous neointimal hyperplasia, irrespective of the generation of the stent.

Data envelopment analysis procedure with two non-homogeneous DMU groups

The classic data envelopment analysis (DEA) model is used to evaluate decision-making units' (DMUs) efficiency under the assumption that all DMUs are evaluated with the same criteria setting. Recently, new researches begin to focus on the efficiency analysis of non-homogeneous DMU arose by real practices such as the evaluation of departments in a university, where departments argue for the adoption of different criteria based on their disciplinary characteristics. A DEA procedure is proposed in this paper to address the efficiency analysis of two non-homogeneous DMU groups. Firstly, an analytical framework is established to compromise diversified input and output (IO) criteria from two non-homogenous groups. Then, a criteria fusion operation is designed to obtain different DEA analysis strategies. Meanwhile, Friedman test is introduced to analyze the consistency of all efficiency results produced by different strategies. Next, ordered weighted averaging (OWA) operators are applied to integrate different information to reach final conclusions. Finally, a numerical example is used to illustrate the proposed method. The result indicates that the proposed method relaxes the restriction of the classical DEA model, and can provide more analytical flexibility to address different decision analysis scenarios arose from practical applications.

Predictors of left ventricular hypertrophy in children on chronic peritoneal dialysis

Conflicting results have been reported in small non-homogenous groups of children with chronic renal failure in terms of casual blood pressure and ambulatory blood pressure monitoring (ABPM) parameters and left ventricular hypertrophy (LVH). The aim of our study was to assess the value of ABPM and hematological and biochemical parameters in predicting LVH in children on chronic peritoneal dialysis (CPD). Echocardiography and 24-h ABPM were performed in addition to routine biochemical and hematological evaluations in 47 children on CPD (26 male, 21 female; mean age 14.74 +/- 3.52 years). Mean daytime systolic blood pressure (SBP) and mean daytime diastolic blood pressure (DBP) values were found to be higher than the mean casual SBP and DBP (p = 0.001) values. Thirty-three (70.2%) children had LVH. The correlations between the left ventricular mass index and ABPM variables were good. Stepwise multiple regression analysis revealed daytime SBP load (beta = 0.652; p < 0.01) and hematocrit (beta = -0.282; p < 0.01) to be independent predictors of LVH. The sensitivity, specificity, positive predictive value, and negative predictive values for the combination of the SBP load >15% and hematocrit value <31% for predicting LVH were 95 [95% confidence interval (CI) 76-99], 78 (95%CI 45-94), 91 (95%CI 73-98), and 88% (95%CI 69-96%), respectively. We conclude that: (1) LVH is prevalent in children on CPD, and (2) a target hematocrit level >31% and daytime SBP load <15% may be preventive for the progression of LVH in the follow-up of children on CPD.

Activity synchrony and social cohesion: a fission-fusion model.

A social group can only be spatially coherent if its members synchronize activities such as foraging and resting. However, activity synchronization is costly to individuals if it requires them to postpone an activity that would be personally more profitable in order to do what the rest of the group is doing. Such costs will be particularly high in groups whose members belong to different age, size or sex classes since the optimal allocation of time to various activities is likely to differ between such classes. Thus, differences in the costs of activity synchronization between and within classes could cause non-homogenous groups to be less stable than homogenous groups, with the result that homogenous groups predominate in the population: that is, they could cause 'social segregation' of animals of different sex, size or age. We develop a model that predicts the degree of social segregation attributable to differences in activity synchronization between homogenous and non-homogenous groups and use this model in determining whether activity synchronization can explain intersexual social segregation in red deer (Cervus elaphus). Differences in activity synchronization between mixed-sex and unisex groups of red deer explained 35% of the observed degree of intersexual social segregation, showing that activity synchronization is an important cause of social segregation in this species.

A mathematical theory of instruction: Instructor/learner interaction and instruction pacing

In this paper, a mathematical theory of instruction applicable in the educational environment is developed from concepts of psychological learning theory. Within the framework of optimization and control theory, the dynamics of the interaction between instructor and learner are modelled, and the trade-off between instruction cost and learner achievement is formulated so that optimal instruction inputs can be determined. One important aspect of the classroom environment that is characterized by the theory is the interaction between an instructor and a group of learners with various learning abilities. A basic dynamic model that relates learner achievement and instruction cost is developed from learning theory concepts. This model, which applies to the individual learner situation, is analyzed in detail to determine instruction intensity inputs that match the learner's characteristics in order to maximize an objective that measures both achievement and cost. This basic model is used as a building block to describe how individual learner achievement depends on instruction pacing. To determine optimal instruction pacing the concept of gain, which is essentially learner achievement per unit time, is introduced. In this extended model, instruction pacing is intimately related with the concept of learner aptitude. This relationship leads immediately to the consideration of instruction pacing for a group of learners with various aptitudes and thus optimal instruction pacing is determined for nonhomogenous groups. Throughout the development of the theory, hypothetical examples are presented to demonstrate many of the implications of the theory. One of the contributions of the theory is the definition of the concepts of learner aptitude and instruction pacing within a framework that structures the empirical investigation of these concepts by means of experimental research.