Simulation-Based and Experimental Studies of Subjective Clustering and Bootstrap Application to Subjective Clustering

2007 ◽  
Author(s):  
Ramaprasad E. Lakshminarayana ◽  
Nishant Bhardwaj ◽  
Shun Takai
Keyword(s):  
Experimental Studies ◽  
Population Data ◽  
Point Estimate ◽  
Experimental Population ◽  
Customer Needs ◽  
Simulation Based ◽  
Sample Data ◽  
Population Sizes ◽  
Data Grouping ◽  
Bootstrap Application

The success of any product in today’s competitive market is dictated by its ability to satisfy the needs of the customers. In this effort, it is important to group similar needs to recognize representative needs, and then identify product requirements that can fulfill these representative needs. One approach to this is to apply Subjective Clustering (SC) to sample data (grouping of customer needs by a sample of customers); however, clusters obtained by SC give only a point estimate of the primary clusters of customer needs by the entire population of customers (population primary clusters). Applying Bootstrap to SC (BS-SC) helps engineers to make inferences on the population primary clusters. In this paper, we randomly pulled out samples of different sizes from both the simulation approach using simulation-generated population data and the empirical approach using experimental population data, and compared the accuracies of SC and BS-SC. Regardless of population sizes, when the sample size was small, BS-SC was more accurate than SC in estimating the population primary clusters. Also, the BS-SC and SC estimates were similar for both simulation and empirical approaches.

Investigating the Accuracy of Subjective Clustering and Bootstrap Application to Subjective Clustering Using an Empirical Population

2006 ◽  
Author(s):  
Nishant Bhardwaj ◽  
Shun Takai
Keyword(s):  
Sample Size ◽  
New Product ◽  
Point Estimate ◽  
Customer Needs ◽  
Bootstrap Application

For a new product to be successful in today's market, engineers need to identify representative customer needs. One approach to identify representative needs from a large number of needs is Subjective Clustering (SC). A set of clusters obtained from SC is a point estimate of clusters generated by a population of customers. Another approach is to apply Bootstrap (BS) to SC. By applying BS to SC, engineers can draw an inference about population primary clusters. This paper compares the accuracy of estimating population primary clusters using SC and Bootstrap applied to SC (BS-SC). The authors recruited participants to perform the clustering experiments and assumed that these participants consist a population. The authors randomly sampled subsets of participants and evaluated how accurately SC and BS-SC identify population primary clusters. When the sample size is small relative to the population, BS-SC estimated population primary clusters more accurately than SC.

Investigation of Regression-Based Effect Size Methods Developed in Single-Subject Studies

2021 ◽  
pp. 014544552110540
Author(s):  
Nihal Sen
Keyword(s):  
Effect Size ◽  
Experimental Studies ◽  
Single Subject ◽  
Single Subject Design ◽  
Data Set ◽  
Design Studies ◽  
Sample Data ◽  
The Difference ◽  
D Values ◽  
Effect Size Calculation

The purpose of this study is to provide a brief introduction to effect size calculation in single-subject design studies, including a description of nonparametric and regression-based effect sizes. We then focus the rest of the tutorial on common regression-based methods used to calculate effect size in single-subject experimental studies. We start by first describing the difference between five regression-based methods (Gorsuch, White et al., Center et al., Allison and Gorman, Huitema and McKean). This is followed by an example using the five regression-based effect size methods and a demonstration how these methods can be applied using a sample data set. In this way, the question of how the values obtained from different effect size methods differ was answered. The specific regression models used in these five regression-based methods and how these models can be obtained from the SPSS program were shown. R2 values obtained from these five methods were converted to Cohen’s d value and compared in this study. The d values obtained from the same data set were estimated as 0.003, 0.357, 2.180, 3.470, and 2.108 for the Allison and Gorman, Gorsuch, White et al., Center et al., as well as for Huitema and McKean methods, respectively. A brief description of selected statistical programs available to conduct regression-based methods was given.

Experimental studies of load characteristics of bogie frames for 350 km/h EMUs

2011 ◽  
Vol 226 (2) ◽  
pp. 216-227 ◽  
Author(s):  
Z Ren ◽  
S Sun ◽  
Q Li ◽  
Z Liu
Keyword(s):  
High Speed ◽  
Experimental Studies ◽  
Lateral Force ◽  
Load Spectrum ◽  
Dynamic Stresses ◽  
Dynamic Coefficients ◽  
Sample Data ◽  
Load Characteristics ◽  
Amplitude Level ◽  
Track Irregularities

In this paper,methods to measure the axle spring load, trailing arm seat lateral force and dynamic stresses of powered and non-powered bogies of a 350 km/h electrical-multi-unit (EMU) are presented. The dynamic amplitude and Hilbert transform of the sample data are used to investigate the characteristics of the forces and the stresses for the EMU running on typical sections including high-speed division, turnout zone, curves, and depot entrance. The load spectrum is then introduced to survey the amplitude level and the number of occurrence of the loads and stresses. Dynamic coefficients of the loads are compared with the recommended values in the Code UIC615-4. The effects of track irregularities and vibrations of gear boxes and motors on the loads and stresses are investigated and the measured loads are classified into six types according to effects of forces on the bogie's movement. The characteristics of the measured loads are useful to establish load conditions for laboratory tests of bogie’s fatigue assessment.

Biology of the Gene: The Ergon/Chronon System

1969 ◽  
Vol 18 (4) ◽  
pp. 329-380 ◽  
Author(s):  
L. Gedda ◽  
G. Brenci
Keyword(s):  
Experimental Studies ◽  
Bone Age ◽  
Specific Information ◽  
Experimental Population ◽  
Association Index ◽  
Temporal Dimension ◽  
Individual Gene ◽  
Amount Of Information ◽  
Biological Time ◽  
The Stability

SummaryThe concordance of physiological and pathological times in human identical twin pairs induced the authors to postulate the existence of a hereditary biological time.Having formulated the hypothesis that the information of each gene has a given period of existence and that, therefore, every gene has its own inherited temporal dimension, the authors report on five different experimental studies intended to verify their hypothesis.In the first study (cf II. 1) a twin research on bone age and dental age is performed. The chronological study of the appearance of ossification nuclei in carpal bones and of mineralization of the gems of permanent dentition, in 20 MZ and 20 DZ human twin pairs, indicates that these wellknown “biological timetables” exhibit about 70% of genotypical control.In order to verify whether biological time is a function of the genotype as a whole, or a property of each individual gene, the authors carried out an experimental study on the mean lifespan in different strains of Drosophila melanogaster whose genotypes were fully known (cf II.2). Their results indicate that the specific information of certain genes controls the insect's lifespan; it may also be inferred that the differential persistence of its specific information is an attribute of each individual gene. This chronological dimension of the gene is called chronon, which the authors also define as “the period during which the original information of the gene remains unchanged” — whether it is used for transcription or duplication, or it remains at the potential stage.The determination of alkaline phosphatase activity in the same strains of D. melanogaster (cf II.3) affords an estimate of the amount of genie information (intensity of the individual trait) and the variation thereof during the gene's chronon. The authors observe that the amount of information decreases gradually during the gene's chronon, suggesting that this be due to the gradual exhaustion of a given specific energy. The decrease in the amount of information in the longitudinal study of chronon leads the authors to identify a further fundamental parametric unit of the gene which they call ergon.Ergon is defined as “the degree of stability of a gene”.In the fourth study (cf II.4) the twin test is applied to the chromosome association index in subcultures of lymphocytes from MZ and DZ twins at age 6 and age 60. This study affords a parallel estimate of chronon (i.e., duration of information) and ergon (i.e., stability of information).Chronon and ergon are found to be interrelated; they may be considered as variables in a dimensional equation of the gene. Thus, the existence of the Ergon/Chronon (E/C) system is postulated.Nine parameters of development and of senescence (first smile, first word, first steps, first pubic hair, menarche, first white hair, first loss of a permanent tooth, first use of reading glasses, onset of menopause) are studied in an experimental population of 666 twin pairs of either zygosity, leading the authors to formulate several conclusions concerning the characteristics of the E/C system (cf II.5).The interpretation of their experimental findings leads the authors to consider the ergon (energy of stability) of a gene as the total result of the stabilities of all the nucleotides making up the DNA sequence of that gene. Since it is well known that the stability of adenine-thymine (AT) bonds exceeds the stability of guanine-cytosine (GC) bonds, and that different combinations of codons (differing in at least one nucleotide) may provide the same information, it is clear that identical polypeptide chains may be produced under the control of genetically different ergons resulting in genetically different chronons.The authors summarize these concepts in the following two aphorisms: “one gene, one stability” (ergon) and “one gene, one time” (chronon).Biological time, development, senescence, homeostasis and disease are interpreted by the authors in the light of the E/C system.

Sensory discrimination: decision process

1980 ◽  
Vol 43 (6) ◽  
pp. 1771-1792 ◽  
Author(s):  
K. O. Johnson
Keyword(s):  
Experimental Design ◽  
Neural Activity ◽  
Decision Process ◽  
Experimental Studies ◽  
Experimental Designs ◽  
Neural Representation ◽  
Mathematical Representation ◽  
Sensory Discrimination ◽  
Sample Data ◽  
Sensory Processes

1. This paper and a following paper deal with problems, such as the following, that arise in experimental studies of the neural mechanisms underlying sensory discrimination: What measures of neural activity are relevant in such a study? How can sample data from the responses of single neurons be combined to represent the information relayed by a population of neurons? How can neural data be compared with results from psychophysical studies? What assumptions are implicit in any such comparison? What are the implications of assumptions that neurons respond independently or that they have homogeneous response properties? How can neural codes be assessed in a systematic way? Can psychophysical and neurophysiological observations be combined to infer mechanisms or relationships in the processes underlying discrimination? All of these questions require some theoretical framework before they can be answered. These papers set out such a framework, they deal with most of those questions, and they provide practicable formulas for relating sample data from neurophysiological experiments to behavioral measures derived from psychophysical experiments. 2. The processes that intervene between a relatively peripheral array of neural activity and a subject's decision in a discrimination task are split into two sections: a) the ascending sensory processes that provide the final patterns of neural activity on which discrimination is based, and b) a process that yields decisions of the type required by the experimental design used in the psychophysical study. The approach is to develop a theory of the decision process in this paper, and then to expand it to incorporate the ascending processes in the following paper. 3. The decision theory deals with a class of experimental designs in which a subject is required to make a decision about two stimuli S1 and S2 (e.g., S1 is larger than S2, S2 is the same as S1, S2 was the modified stimulus, and so on). A mathematical representation for experimental designs of this type is developed. 4. The decision process is analyzed in two forms: a) a multivariate form in which the discrimination decision results directly from multidimensional neural representation of the two stimuli, and b) a vivariate form in which the final representation of each stimulus is a unidimensional variable. Conditions required for equivalence of these formulations are examined. 5. The theory includes as explicit variables a) the experimental design, b) the subject's discrimination strategy, c) bias, d) memory variance, e) bias variance, f) variance in the final neural representations of the stimuli, and g) their functional dependence on the stimuli that they represent. 6. Formulas are developed for the expected values of commonly used psychophysical measures such as the classical psychometric function, receiver operating characteristic (ROC) functions, discriminatory separation index (d'), and the difference limen. 7. Optimum discrimination behavior is analyzed.

scholarly journals The effect of spatial variation for predicting aphid epidemics

2018 ◽  
Author(s):  
Christian Damgaard ◽  
Marianne Bruus ◽  
Jørgen Aagaard Axelsen
Keyword(s):  
Spatial Variation ◽  
Spatial Scale ◽  
Spatial Data ◽  
Population Data ◽  
Aphid Population ◽  
Bayesian Hierarchical ◽  
Fitting Procedure ◽  
Population Sizes ◽  
Spatio Temporal ◽  
Epidemic Development

AbstractIn order to improve forecasting of aphid epidemics, it is important to know the spatial scale at which specific forecasts are reliable. To investigate the spatial scale of aphid epidemics, we have developed a spatio-temporal stochastic aphid population growth model, and fitted the model to empirical spatial time-series aphid population data using a Bayesian hierarchical fitting procedure. Furthermore, detailed spatial data of the initial phases of epidemic development was investigated in a semivariogram. Our results suggest that there is limited spatial variation in the initial occurrence probability at a spatial scale of 10 km. Consequently, the results support the hypothesis that initial aphid population sizes and epidemics may be predicted in fields within a 10 km radius. For farmers, this may imply that they can rely their decision of whether to spray against aphids on observations made by other nearby farmers or by the consultancy service.

scholarly journals Genomic reconstruction of 100 000-year grassland history in a forested country: population dynamics of specialist forbs

2019 ◽  
Vol 15 (5) ◽  
pp. 20180577 ◽  
Author(s):  
Yuichi Yamaura ◽  
Ayu Narita ◽  
Yoshinobu Kusumoto ◽  
Atsushi J. Nagano ◽  
Ayumi Tezuka ◽  
...  
Keyword(s):  
Forest Harvesting ◽  
Land Uses ◽  
Grassland Species ◽  
Grassland Ecosystems ◽  
Simulation Based ◽  
Population Sizes ◽  
Extensive Farming ◽  
Contemporary Management ◽  
Demographic Simulation ◽  
Grassland Biodiversity

Grassland ecosystems worldwide have been extensively converted to other land uses and are globally imperiled. Because many grasslands have been maintained by human activities, understanding their origin and history is fundamentally important to better contemporary management. However, existing methods to reconstruct past vegetation can produce contrasting views on grassland history. Here, we inferred demographic histories of 40 populations of four grassland forb species throughout Japan using high-resolution genome sequences and model-flexible demographic simulation based on the site frequency spectrum. Although two species showed a slight decline in population size between 100 000–10 000 years ago, our results suggest that population sizes of studied species have been maintained within the range of 0.5–2.0 times the most recent estimates for at least 100 000 years across Japan. Our results suggest that greater than 90% declines in Japanese grasslands and subsequent losses of grassland species in the last 100 years are geologically and biologically important and will have substantial consequences for Japanese biota and culture. People have had critical roles in maintaining disturbance-dependent grassland ecosystems and biota in this warm and wet forested country. In these contexts, disturbances associated with forest harvesting and traditional extensive farming have the potential to maintain grassland ecosystems and can provide important opportunities to reconcile resource production and conservation of grassland biodiversity.

Estimating the true arrival, balking, and reneging processes from censored transactional data: a simulation-based approach

SIMULATION ◽  
2021 ◽  
pp. 003754972110611
Author(s):  
Ashkan Negahban
Keyword(s):  
Stochastic Processes ◽  
Call Center ◽  
Capacity Planning ◽  
Queueing Systems ◽  
Data Repository ◽  
Online Data ◽  
Real World Application ◽  
Simulation Based ◽  
Sample Data ◽  
Transactional Data

The transactional data typically collected/available on queueing systems are often subject to censoring as unsuccessful arrivals due to balking and/or unserved entities due to reneging are not recorded. In fact, in many situations, the true arrival, balking, and reneging events are unobservable, making it virtually impossible to collect data on these stochastic processes—information that is crucial for capacity planning and process improvement decisions. The objective of this paper is to estimate the true (latent) external arrival, balking, and reneging processes in queueing systems from such censored transactional data. The estimation problem is formulated as an optimization model and an iterative simulation-based inference approach is proposed to find appropriate input models for these stochastic processes. The proposed method is applicable in any complex queueing situation as long as it can be simulated. The problem is investigated under both known and unknown reneging distribution. Through extensive simulation experiments, general guidelines are provided for specifying the parameters of the proposed approach, namely, sample size and number of replications. The proposed approach is also validated through a real-world application in a call center, where it successfully estimates the underlying arrival, balking, and reneging distributions. Finally, to enable reproducibility and technology transfer, a working example, including all codes and sample data, are made available in an open online data repository associated with this paper.

MODELING PARASITE REDUCTION MECHANISMS IN CHAGAS DISEASE

2015 ◽  
Vol 23 (supp01) ◽  
pp. S1-S15
Author(s):  
S. VEGA-ROYERO ◽  
G. J. SIBONA ◽  
S. CASTAÑO ◽  
C. A. CONDAT
Keyword(s):  
Chagas Disease ◽  
Mixed Infection ◽  
Cell Damage ◽  
Population Data ◽  
Phase Portraits ◽  
Experimental Population ◽  
Ganglioside Gm1 ◽  
Host Interaction ◽  
Reduction Mechanisms ◽  
Pathogenic Parasite

Various procedures have been proposed to reduce parasitemia during Chagas disease. Here we analyze in detail models developed to predict the possible outcomes of two of these treatments. The model solutions reproduce available experimental population data and can be used as tools to help researchers to find a cure or, at least, an optimal treatment to reduce cardiac cell damage. In particular, we study how the phase diagram describing the infection outcome is modified by the application of the ganglioside GM1, finding the optimum concentration of the drug in terms of the parameters characterizing its influence on the parasite-host interaction. We also investigate the use of the non-pathogenic parasite T. rangeli to reduce T. cruzi load in a mixed infection, finding that this method is not effective against all T. cruzi strains. Furthermore, we compare phase portraits of the evolution of the disease for a single and a mixed infection, and evaluate the cell damage as a function of the time elapsed between both infections, remarking on the temporary protective effect of the reaction to T. rangeli.

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