scholarly journals Estimation of Non-Linear Parameters with Data Collected Using Respondent-Driven Sampling

Mathematics ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 1315
Author(s):  
Ismael Sánchez-Borrego ◽  
María del Mar Rueda ◽  
Héctor Mullo
Keyword(s):  
Correlation Coefficient ◽  
Simulation Study ◽  
Sampling Method ◽  
Future Research ◽  
Respondent Driven Sampling ◽  
Sampling Frame ◽  
Hidden Populations ◽  
Sample Weight ◽  
Non Linear ◽  
Weight Method

Respondent-driven sampling (RDS) is a snowball-type sampling method used to survey hidden populations, that is, those that lack a sampling frame. In this work, we consider the problem of regression modeling and association for continuous RDS data. We propose a new sample weight method for estimating non-linear parameters such as the covariance and the correlation coefficient. We also estimate the variances of the proposed estimators. As an illustration, we performed a simulation study and an application to an ethnic example. The proposed estimators are consistent and asymptotically unbiased. We discuss the applicability of the method as well as future research.

scholarly journals B-Graph Sampling to Estimate the Size of a Hidden Population

2015 ◽  
Vol 31 (4) ◽  
pp. 723-736 ◽  
Author(s):  
Marinus Spreen ◽  
Stefan Bogaerts
Keyword(s):  
Social Network ◽  
Sampling Design ◽  
Respondent Driven Sampling ◽  
Sampling Frame ◽  
Hidden Populations ◽  
Hidden Population ◽  
Graph Sampling ◽  
Graph Design ◽  
Applied Design ◽  
Incomplete Sampling

Abstract Link-tracing designs are often used to estimate the size of hidden populations by utilizing the relational links between their members. A major problem in studies of hidden populations is the lack of a convenient sampling frame. The most frequently applied design in studies of hidden populations is respondent-driven sampling in which no sampling frame is used. However, in some studies multiple but incomplete sampling frames are available. In this article, we introduce the B-graph design that can be used in such situations. In this design, all available incomplete sampling frames are joined and turned into one sampling frame, from which a random sample is drawn and selected respondents are asked to mention their contacts. By considering the population as a bipartite graph of a two-mode network (those from the sampling frame and those who are not on the frame), the number of respondents who are directly linked to the sampling frame members can be estimated using Chao’s and Zelterman’s estimators for sparse data. The B-graph sampling design is illustrated using the data of a social network study from Utrecht, the Netherlands.

scholarly journals Stickiness of respondent-driven sampling recruitment chains

2014 ◽  
Vol 2 (2) ◽  
pp. 298-301 ◽  
Author(s):  
JACOB C. FISHER ◽  
M. GIOVANNA MERLI
Keyword(s):  
Risk Behaviors ◽  
Sex Workers ◽  
Drug Users ◽  
Female Sex Workers ◽  
Sampling Method ◽  
Respondent Driven Sampling ◽  
Hidden Populations ◽  
Sampling Process ◽  
Population Subgroup ◽  
Hard To Reach Populations

Respondent-driven sampling (RDS) is an increasingly popular chain-referral sampling method. Although it has proved effective at generating samples of hard to reach populations—meaning populations for which sampling frames are not available because they are hidden or socially stigmatized like sex workers or injecting drug users—quickly and cost-effectively, the ease of collecting the sample comes with a cost: bias or inefficiency in the estimates of population parameters (Gile & Handcock, 2010; Goel & Salganik, 2010). One way that RDS can produce inefficient estimates is if one or more of the recruitment chains gets stuck among members of a cohesive subpopulation, preventing the RDS sampling process from exploring other areas of the network. If that happens, members of the population subgroup recruit one another repeatedly, leading to an increase in sample size without increasing the diversity of the sample. This type of stickiness is particularly likely when hidden populations are stratified, and the stratified groups are organized into venues that provide opportunities to recruit other members of the same stratum. Female sex workers (FSW) in China, who are stratified into tiers of sex work that are correlated with marital status, age, and risk behaviors, are a prime example (Merli et al., 2014; Yamanis et al., 2013). Chinese FSW recruit clients from venues such as karaoke bars, massage parlors, or street corners. At larger venues, sex workers who participate in an RDS study might recruit other members of the same venue into the study at a higher rate than expected, leading to inefficient estimates. In short, the chain could get stuck in a venue.

scholarly journals Respondent-Driven Sampling for Surveying Ethnic Minorities in Ecuador

2020 ◽  
Vol 12 (21) ◽  
pp. 9102
Author(s):  
Héctor Mullo ◽  
Ismael Sánchez-Borrego ◽  
Sara Pasadas-del-Amo
Keyword(s):  
Ethnic Minority ◽  
Confidence Intervals ◽  
Ethnic Minorities ◽  
Sampling Method ◽  
Diagnostic Tools ◽  
Respondent Driven Sampling ◽  
Hidden Populations ◽  
Economic Issues ◽  
Socioeconomic Issues ◽  
Hard To Reach Populations

In this work, we consider the problem of surveying a population of young Indigenous, Montubios and Afro-Ecuadorians to study their living conditions and socioeconomic issues. We conducted a Respondent-driven sampling (RDS) survey in the canton of Riobamba, Ecuador. RDS is a network-based sampling method intended to survey hidden or hard-to-reach populations. We have obtained RDS estimates and confidence intervals of these characteristics. We have illustrated and discussed some of the assumptions of the method using some available diagnostic tools. Our results suggest that RDS is an effective methodology for studying social and economic issues of this ethnic minority in Ecuador. This technique is relatively easy to implement and has the potential to be applied to survey other hidden populations in other settings.

An Analysis of Lexical Chunks in Online Business Letters (OBL) and Business Letter Corpus (BLC): A Corpus-Based Study

2020 ◽  
Vol 4 (2) ◽  
pp. 63
Author(s):  
Hairul Azhar Mohamad ◽  
Muhammad Luthfi Mohaini ◽  
Pavithran Ravinthra Nath
Keyword(s):  
Comparative Analysis ◽  
Sampling Method ◽  
Future Research ◽  
Frequent Type ◽  
Sentence Level ◽  
Lexical Collocations ◽  
Online Business ◽  
Lexical Density ◽  
Concordance Program ◽  
Corporate Business

This research investigated into the lexical density and frequencies of five types of lexical chunks located in 300 online business letters. Top 10 websites on business correspondence had been identified in terms of traffic visitors and bounce rate under one million web rankings worldwide. Criterion Sampling method was identified prior to extracting the sample letters from the websites. The data was then run with Antconc Concordance Program (ACP) for lexical density and frequency analysis. Top 15 lexical chunks in online business letters (OBL) were compared against those top 15 in Business Letter Corpus (BLC). Findings revealed that there was a total of 39 916-word tokens and 939 counts of lexical chunks found in this corpus. It was found that more lexical words do not imply more lexical chunks used in based on types of business letters.  All 5 types of lexical chunks were identified and ranked in descending order; Sentence Builders (SB) as the most frequent type, followed by Collocations (COL), Deictic locutions (DLs), Polywords (POLs) and Institutionalized Expressions (IUs) as the least frequent type of lexical chunk. Sub-divisional analysis indicated that Grammatical Collocations (GCs) were more common than Lexical Collocations (LCs). Majority of lexical chunks were formed more at sentence level than phrasal level. Comparative analysis between top 15 lexical chunks in OBL and BLC discovered that most top lexical chunks in online business letters are representative of those corporate business letters in BLC. Pedagogical implications in terms of the reliability of online business letters for academic reference and future research considerations are also addressed.

scholarly journals Psychometric Properties of the MyotonPRO in Dementia Patients with Paratonia

Gerontology ◽  
2017 ◽  
Vol 64 (4) ◽  
pp. 401-412 ◽  
Author(s):  
Hans Drenth ◽  
Sytse U. Zuidema ◽  
Wim P. Krijnen ◽  
Ivan Bautmans ◽  
Cees van der Schans ◽  
...  
Keyword(s):  
Psychometric Properties ◽  
Correlation Coefficient ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Functional Mobility ◽  
Future Research ◽  
Minimal Detectable Change ◽  
Muscle Properties ◽  
Dementia Patients ◽  
Longitudinal Outcome

Background: Paratonia is a distinctive form of hypertonia, causing loss of functional mobility in early stages of dementia to severe high muscle tone and pain in the late stages. For assessing and evaluating therapeutic interventions, objective instruments are required. Objective: Determine the psychometric properties of the MyotonPRO, a portable device that objectively measures muscle properties, in dementia patients with paratonia. Methods: Muscle properties were assessed with the MyotonPRO by 2 assessors within one session and repeated by the main researcher after 30 min and again after 6 months. Receiver operating characteristic curves were constructed for all MyotonPRO outcomes to discriminate between participants with (n = 70) and without paratonia (n = 82). In the participants with paratonia, correlation coefficients were established between the MyotonPRO outcomes and the Modified Ashworth Scale for paratonia (MAS-P) and muscle palpation. In participants with paratonia, reliability (intraclass correlation coefficient) and agreement values (standard error of measurement and minimal detectable change) were established. Longitudinal outcome from participants with paratonia throughout the study (n = 48) was used to establish the sensitivity for change (correlation coefficient) and responsiveness (minimal clinical important difference). Results: Included were 152 participants with dementia (mean [standard deviation] age of 83.5 [98.2]). The area under the curve ranged from 0.60 to 0.67 indicating the MyotonPRO is able to differentiate between participants with and without paratonia. The MyotonPRO explained 10-18% of the MAS-P score and 8-14% of the palpation score. Interclass correlation coefficients for interrater reliability ranged from 0.57 to 0.75 and from 0.54 to 0.71 for intrarater. The best agreement values were found for tone, elasticity, and stiffness. The change between baseline and 6 months in the MyotonPRO outcomes explained 8-13% of the change in the MAS-P scores. The minimal clinically important difference values were all smaller than the measurement error. Conclusion: The MyotonPRO is potentially applicable for cross-sectional studies between groups of paratonia patients and appears less suitable to measure intraindividual changes in paratonia. Because of the inherent variability in movement resistance in paratonia, the outcomes from the MyotonPRO should be interpreted with care; therefore, future research should focus on additional guidelines to increase the clinical interpretation and improving reproducibility.

Accessible tourism: a bibliometric review (2008–2020)

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Guanghui Qiao ◽  
Liu Ding ◽  
Linlin Zhang ◽  
Huili Yan
Keyword(s):  
English Language ◽  
Research Literature ◽  
Future Research ◽  
Sampling Frame ◽  
Multiple Sources ◽  
Knowledge Maps ◽  
Tourism Research ◽  
Content Type ◽  
The Usa ◽  
Bibliometric Review

Purpose The purpose of this paper is to reveal the knowledge evolution process, research hotspots and future trends in the accessible tourism research literature from 2008 to 2020. Design/methodology/approach A total of 213 articles on accessible tourism were selected from the core collection database of Web of Science (WoS) and analyzed using CiteSpace. Findings Over the 13-year period between 2008 and 2020, an increasing number of studies have been published concerning accessible tourism, but the overall base is still small. The research content mainly includes six modules. Among institutions, the University of Technology Sydney has published the largest number of papers. Cooperation among countries involves the USA, the United Kingdom, Australia, Portugal and China. Tourism Management is the leading journal for disseminating research on accessible tourism. Definition of “Accessible tourism” and the different scope of this phenomenon are re-discussed. In recent years, “experience” and “participation” have become the “new favorites” in accessible tourism research, which could reveal insights into future research directions. Research limitations/implications The sampling frame was defined in terms of the WoS database and even though this is an important database for global academic information, in the big data era, the authors may have to integrate information from multiple sources to comprehensively reveal and understand knowledge maps. Second, because of the operational constraints of the CiteSpace software, the authors only selected outputs published in peer-reviewed journals, excluding other published works, such as books and conference papers. Finally, because of the language restrictions of the authors, this research is limited to journals published in the English language. Practical implications Practically, the results of this study made a conclusion of accessible tourism research so that the researchers can easily know what has currently been done and what future research can do. Tourism managers can also understand the demands and the constraints of tourism for the people who have barriers to travel. They can supply more specific products for the accessible tourism and further promote the construction of barrier-free travel environments. Originality/value This paper unifies the literature on senior tourism and people with disabilities tourism, and uses CiteSpace to construct data and network visualizations, including a burst and dynamic analysis for the period covered by the sample. Furthermore, this paper proposed a more diversified accessible tourism.

A new sampling method in particle filter based on Pearson correlation coefficient

2016 ◽  
Vol 216 ◽  
pp. 208-215 ◽  
Author(s):  
Haomiao Zhou ◽  
Zhihong Deng ◽  
Yuanqing Xia ◽  
Mengyin Fu
Keyword(s):  
Particle Filter ◽  
Correlation Coefficient ◽  
Sampling Method ◽  
Pearson Correlation ◽  
Pearson Correlation Coefficient

scholarly journals LIVELIHOOD SUSTAINABILITY AMONG ROHINGYA REFUGEES: A CASE STUDY IN TAMAN SENANGIN, SEBERANG PERAI, PENANG

2019 ◽  
Vol 4 (2) ◽  
pp. 46-48 ◽  
Author(s):  
Yasmin Salim
Keyword(s):  
Small Proportion ◽  
Household Income ◽  
Random Sampling ◽  
Sampling Method ◽  
Simple Random Sampling ◽  
Sustainable Livelihood ◽  
Sampling Frame ◽  
Household Expenditures ◽  
Official Status

A person’s livelihood implies as the means of securing the basic necessities of life, example food, water, shelter and clothing. A livelihood is sustainable only when they can address, recover, maintain or enhance their necessities, now and the future. However, Rohingya refugee is lack of official status in Malaysia and they have a limited access on a sustainable livelihood. This study aims to understand and determine whether the current household income able to create a sustainable livelihood. The sample was selected based on simple random sampling method for which the sampling frame are those refugees reside in Taman Senangin. The findings indicate majority of household expenditures increases while saving, were allocated only a small proportion of their remaining income. Hence, with the small proportion of saving, they are able to survive day-to-day life and are sustainable if the proportion of saving increased.

Non-Linear Control of a Neutralisation Process

1971 ◽  
Vol 4 (9) ◽  
pp. T151-T157 ◽  
Author(s):  
P D Roberts
Keyword(s):  
Simulation Study ◽  
Digital Simulation ◽  
Linear Control ◽  
Attractive Alternative ◽  
Error Signal ◽  
Linear Controller ◽  
Linear Characteristic ◽  
Non Linear ◽  
On Line ◽  
Extra Parameter

The paper describes a digital simulation study of the application of a non-linear controller to the regulation of a single stage neutralisation process. In the controller, the proportional gain increases with amplitude of controller error signal. The performance of the non-linear controller is compared with that of a conventional linear controller and with the performance obtained by employing a linear controller with a linearisation network designed to compensate for the non-linear characteristic of the neutralisation curve. Although the performance of the non-linear controller is inferior to that obtained by employing a perfect linearisation network, its performance is still considerably superior to that obtained by using a conventional linear controller when operating at a symmetrical point on the neutralisation curve. In contrast to the linearisation network technique, the non-linear controller contains only one extra parameter and can be readily tuned on-line without prior knowledge of the neutralisation curve. Hence, it can be considered as an attractive alternative for the control of neutralisation processes.

Sign in / Sign up

Export Citation Format

Share Document