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  1. Article ; Online: Statistical Analysis of Chemical Element Compositions in Food Science: Problems and Possibilities.

    Templ, Matthias / Templ, Barbara

    Molecules (Basel, Switzerland)

    2021  Volume 26, Issue 19

    Abstract: In recent years, many analyses have been carried out to investigate the chemical components of food data. However, studies rarely consider the compositional pitfalls of such analyses. This is problematic as it may lead to arbitrary results when non- ... ...

    Abstract In recent years, many analyses have been carried out to investigate the chemical components of food data. However, studies rarely consider the compositional pitfalls of such analyses. This is problematic as it may lead to arbitrary results when non-compositional statistical analysis is applied to compositional datasets. In this study, compositional data analysis (CoDa), which is widely used in other research fields, is compared with classical statistical analysis to demonstrate how the results vary depending on the approach and to show the best possible statistical analysis. For example, honey and saffron are highly susceptible to adulteration and imitation, so the determination of their chemical elements requires the best possible statistical analysis. Our study demonstrated how principle component analysis (PCA) and classification results are influenced by the pre-processing steps conducted on the raw data, and the replacement strategies for missing values and non-detects. Furthermore, it demonstrated the differences in results when compositional and non-compositional methods were applied. Our results suggested that the outcome of the log-ratio analysis provided better separation between the pure and adulterated data and allowed for easier interpretability of the results and a higher accuracy of classification. Similarly, it showed that classification with artificial neural networks (ANNs) works poorly if the CoDa pre-processing steps are left out. From these results, we advise the application of CoDa methods for analyses of the chemical elements of food and for the characterization and authentication of food products.
    MeSH term(s) Crocus/chemistry ; Food Contamination/analysis ; Food Technology ; Honey/analysis ; Neural Networks, Computer ; Principal Component Analysis
    Language English
    Publishing date 2021-09-23
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 1413402-0
    ISSN 1420-3049 ; 1431-5165 ; 1420-3049
    ISSN (online) 1420-3049
    ISSN 1431-5165 ; 1420-3049
    DOI 10.3390/molecules26195752
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Privacy of Study Participants in Open-access Health and Demographic Surveillance System Data: Requirements Analysis for Data Anonymization.

    Templ, Matthias / Kanjala, Chifundo / Siems, Inken

    JMIR public health and surveillance

    2022  Volume 8, Issue 9, Page(s) e34472

    Abstract: Background: Data anonymization and sharing have become popular topics for individuals, organizations, and countries worldwide. Open-access sharing of anonymized data containing sensitive information about individuals makes the most sense whenever the ... ...

    Abstract Background: Data anonymization and sharing have become popular topics for individuals, organizations, and countries worldwide. Open-access sharing of anonymized data containing sensitive information about individuals makes the most sense whenever the utility of the data can be preserved and the risk of disclosure can be kept below acceptable levels. In this case, researchers can use the data without access restrictions and limitations.
    Objective: This study aimed to highlight the requirements and possible solutions for sharing health surveillance event history data. The challenges lie in the anonymization of multiple event dates and time-varying variables.
    Methods: A sequential approach that adds noise to event dates is proposed. This approach maintains the event order and preserves the average time between events. In addition, a nosy neighbor distance-based matching approach to estimate the risk is proposed. Regarding the key variables that change over time, such as educational level or occupation, we make 2 proposals: one based on limiting the intermediate statuses of the individual and the other to achieve k-anonymity in subsets of the data. The proposed approaches were applied to the Karonga health and demographic surveillance system (HDSS) core residency data set, which contains longitudinal data from 1995 to the end of 2016 and includes 280,381 events with time-varying socioeconomic variables and demographic information.
    Results: An anonymized version of the event history data, including longitudinal information on individuals over time, with high data utility, was created.
    Conclusions: The proposed anonymization of event history data comprising static and time-varying variables applied to HDSS data led to acceptable disclosure risk, preserved utility, and being sharable as public use data. It was found that high utility was achieved, even with the highest level of noise added to the core event dates. The details are important to ensure consistency or credibility. Importantly, the sequential noise addition approach presented in this study does not only maintain the event order recorded in the original data but also maintains the time between events. We proposed an approach that preserves the data utility well but limits the number of response categories for the time-varying variables. Furthermore, using distance-based neighborhood matching, we simulated an attack under a nosy neighbor situation and by using a worst-case scenario where attackers have full information on the original data. We showed that the disclosure risk is very low, even when assuming that the attacker's database and information are optimal. The HDSS and medical science research communities in low- and middle-income country settings will be the primary beneficiaries of the results and methods presented in this paper; however, the results will be useful for anyone working on anonymizing longitudinal event history data with time-varying variables for the purposes of sharing.
    MeSH term(s) Data Anonymization ; Demography ; Disclosure ; Electronic Health Records ; Humans ; Privacy
    Language English
    Publishing date 2022-09-02
    Publishing country Canada
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ISSN 2369-2960
    ISSN (online) 2369-2960
    DOI 10.2196/34472
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Analysis of chemical compounds in beverages - Guidance for establishing a compositional analysis.

    Templ, Matthias / Templ, Barbara

    Food chemistry

    2020  Volume 325, Page(s) 126755

    Abstract: In recent years, much analysis has been carried out regarding the chemical compositions of nonalcoholic and alcoholic beverages. However, no study has ever considered the compositional pitfalls inherent in such studies, which may lead to arbitrary ... ...

    Abstract In recent years, much analysis has been carried out regarding the chemical compositions of nonalcoholic and alcoholic beverages. However, no study has ever considered the compositional pitfalls inherent in such studies, which may lead to arbitrary results. Two approaches were compared in this paper, compositional data analysis (CoDa) and classical statistical analyses, to demonstrate (1) how aging affects beer and (2) how the results vary depending on the applied approach. Exemplarily, chemical compounds of 43 beer samples were analyzed. Our work has led us to obtain different results when the correlation analysis and principal component analysis were conducted on the unmodified-, log-transformed-, or closed-data in contrary to the analyses of log-ratio coordinates. The outcome of the latter provided better separation between aged and fresh beer samples and also easier interpretability. These results lead us to advise the usage of CoDa methods for the analyses of chemical compositions of beverages.
    Language English
    Publishing date 2020-04-06
    Publishing country England
    Document type Journal Article
    ZDB-ID 243123-3
    ISSN 1873-7072 ; 0308-8146
    ISSN (online) 1873-7072
    ISSN 0308-8146
    DOI 10.1016/j.foodchem.2020.126755
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Change of plant phenophases explained by survival modeling.

    Templ, Barbara / Fleck, Stefan / Templ, Matthias

    International journal of biometeorology

    2017  Volume 61, Issue 5, Page(s) 881–889

    Abstract: It is known from many studies that plant species show a delay in the timing of flowering events with an increase in latitude and altitude, and an advance with an increase in temperature. Furthermore, in many locations and for many species, flowering ... ...

    Abstract It is known from many studies that plant species show a delay in the timing of flowering events with an increase in latitude and altitude, and an advance with an increase in temperature. Furthermore, in many locations and for many species, flowering dates have advanced over the long-term. New insights using survival modeling are given based on data collected (1970-2010) along a 3000-km long transect from northern to eastern central Europe. We could clearly observe that in the case of dandelion (Taraxacum officinale) the risk of flowering time, in other words the probability that flowering occurs, is higher for an earlier day of year in later decades. Our approach assume that temperature has greater influence than precipitation on the timing of flowering. Evaluation of the predictive power of tested models suggests that Cox models may be used in plant phenological research. The applied Cox model provides improved predictions of flowering dates compared to traditional regression methods and gives further insights into drivers of phenological events.
    Language English
    Publishing date 2017-05
    Publishing country United States
    Document type Journal Article
    ZDB-ID 280324-0
    ISSN 1432-1254 ; 0020-7128
    ISSN (online) 1432-1254
    ISSN 0020-7128
    DOI 10.1007/s00484-016-1267-z
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Preservation of Individuals’ Privacy in Shared COVID-19 Related Data

    Sauermann, Stefan / Kanjala, Chifundo / Templ, Matthias / Austin, Claire C.

    SSRN Electronic Journal ; ISSN 1556-5068

    2020  

    Keywords covid19
    Language English
    Publisher Elsevier BV
    Publishing country us
    Document type Article ; Online
    DOI 10.2139/ssrn.3648430
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  6. Article ; Online: Habitat-Dependency of Transect Walk and Pan Trap Methods for Bee Sampling in Farmlands

    Templ Barbara / Mózes Edina / Templ Matthias / Földesi Rita / Szirák Ádám / Báldi András / Kovács-Hostyánszki Anikó

    Journal of Apicultural Science, Vol 63, Iss 1, Pp 93-

    2019  Volume 115

    Abstract: Bees are the most important group of flower visitors providing an essential ecosystem service, namely pollination. Due to the worldwide decline of bees, there should be standardized sampling methods in place to ensure consistent and comparable results ... ...

    Abstract Bees are the most important group of flower visitors providing an essential ecosystem service, namely pollination. Due to the worldwide decline of bees, there should be standardized sampling methods in place to ensure consistent and comparable results between studies. We compared the two commonly used sampling methods of yellow pan traps and transect walk to determine (i) which habitat variables affect the species composition, abundance and species richness of sampled bee communities, (ii) which method potentially contains sampling bias towards some individuals or groups of bees and (iii) the efficiency of sampling in various habitats. We conducted fieldwork in different agricultural habitats distributed along landscape heterogeneity and topography gradients. Our results showed that the height of vegetation, the average number of flowers and the amount of woody vegetation had the greatest influence on the sampling efficiency. Our survey also demonstrated that sampling by transect walk captured less bees in general, especially in stubble, maize, and cereal fields. We found that Apis mellifera and Bombus spp. were well represented in samples collected by the transect walk method, while the abundance of other genera, especially Dasypoda, Hylaeus and Panurgus was higher in pan traps. Based on the results, we suggest (i) the transect walk method to compare samples of flower-visiting wild bee communities from various habitats of different vegetation and flower characteristics, (ii) application of the transect walk or pan traps to compare similar habitats and (iii) adoption of a comprehensive method which would incorporate both sampling techniques to gain a more complex insight into wild bee species composition.
    Keywords bee survey ; insect pollinators ; redundancy analysis ; sampling bias ; transformation-based ; wild bee ; Zoology ; QL1-991
    Subject code 310
    Language English
    Publishing date 2019-06-01T00:00:00Z
    Publisher Sciendo
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  7. Book ; Online: Estimation of social exclusion indicators from complex surveys

    Alfons, Andreas / Templ, Matthias

    the R package laeken

    (KBI ; 1224)

    2012  

    Author's details Andreas Alfons and Matthias Templ
    Series title KBI ; 1224
    Keywords Soziale Ausgrenzung ; Sozialer Indikator ; Schätztheorie
    Language English
    Size Online-Ressource (31 S.), graph. Darst.
    Publisher Kath. Univ. Leuven, Fac. of Business and Economics, Dep. of Decision Sciences and Information Management
    Publishing place Leuven
    Document type Book ; Online
    Note IMD-Felder maschinell generiert
    Database ECONomics Information System

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  8. Article: Habitat-Dependency of Transect Walk and Pan Trap Methods for Bee Sampling in Farmlands

    Templ, Barbara / Báldi, András / Földesi, Rita / Kovács-Hostyánszki, Anikó / Mózes, Edina / Szirák, Ádám / Templ, Matthias

    Journal of apicultural science. 2019 June 01, v. 63, no. 1

    2019  

    Abstract: Bees are the most important group of flower visitors providing an essential ecosystem service, namely pollination. Due to the worldwide decline of bees, there should be standardized sampling methods in place to ensure consistent and comparable results ... ...

    Abstract Bees are the most important group of flower visitors providing an essential ecosystem service, namely pollination. Due to the worldwide decline of bees, there should be standardized sampling methods in place to ensure consistent and comparable results between studies. We compared the two commonly used sampling methods of yellow pan traps and transect walk to determine (i) which habitat variables affect the species composition, abundance and species richness of sampled bee communities, (ii) which method potentially contains sampling bias towards some individuals or groups of bees and (iii) the efficiency of sampling in various habitats. We conducted fieldwork in different agricultural habitats distributed along landscape heterogeneity and topography gradients. Our results showed that the height of vegetation, the average number of flowers and the amount of woody vegetation had the greatest influence on the sampling efficiency. Our survey also demonstrated that sampling by transect walk captured less bees in general, especially in stubble, maize, and cereal fields. We found that Apis mellifera and Bombus spp. were well represented in samples collected by the transect walk method, while the abundance of other genera, especially Dasypoda, Hylaeus and Panurgus was higher in pan traps. Based on the results, we suggest (i) the transect walk method to compare samples of flower-visiting wild bee communities from various habitats of different vegetation and flower characteristics, (ii) application of the transect walk or pan traps to compare similar habitats and (iii) adoption of a comprehensive method which would incorporate both sampling techniques to gain a more complex insight into wild bee species composition.
    Keywords agricultural land ; Apis mellifera ; bees ; Bombus ; corn ; Dasypoda ; ecosystem services ; flowers ; habitats ; Hylaeus ; landscapes ; Panurgus ; pollination ; pollinators ; sampling ; species richness ; stubble ; surveys ; topography ; traps ; vegetation
    Language English
    Dates of publication 2019-0601
    Size p. 93-115.
    Publishing place Sciendo
    Document type Article
    ZDB-ID 2814222-6
    ISSN 2299-4831
    ISSN 2299-4831
    DOI 10.2478/jas-2019-0014
    Database NAL-Catalogue (AGRICOLA)

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  9. Book ; Online: The R package emdi for estimating and mapping regionally disaggregated indicators

    Kreutzmann, Ann-Kristin / Pannier, Sören / Rojas-Perilla, Natalia / Schmid, Timo / Templ, Matthias / Tzavidis, Nikos

    (Diskussionsbeiträge / Fachbereich Wirtschaftswissenschaft : Economics ; 2017, 15)

    2017  

    Abstract: The R package emdi offers a methodological and computational framework for the estimation of regionally disaggregated indicators using small area estimation methods and provides tools for assessing, processing and presenting the results. A range of ... ...

    Author's details Ann-Kristin Kreutzmann, Sören Pannier, Natalia Rojas-Perilla, Timo Schmid, Matthias Templ, Nikos Tzavidis
    Series title Diskussionsbeiträge / Fachbereich Wirtschaftswissenschaft : Economics ; 2017, 15
    Abstract The R package emdi offers a methodological and computational framework for the estimation of regionally disaggregated indicators using small area estimation methods and provides tools for assessing, processing and presenting the results. A range of indicators that includes the mean of the target variable, the quantiles of its distribution and complex, non-linear indicators or customized indicators can be estimated simultaneously using direct estimation and the empirical best predictor (EBP) approach (Molina and Rao 2010). In the application presented in this paper package emdi is used for estimating inequality indicators and the median of the income distributions for small areas in Austria. Because the EBP approach relies on the normality of the mixed model error terms, the user is further assisted by an automatic selection of data-driven transformation parameters. Estimating the uncertainty of small area estimates (using a mean squared error - MSE measure) is achieved by using both parametric bootstrap and semi-parametric wild bootstrap. The additional uncertainty due to the estimation of the transformation parameter is also captured in MSE estimation. The semi-parametric wild bootstrap further protects the user against departures from the assumptions of the mixed model in particular, those of the unit-level error term. The bootstrap schemes are facilitated by computationally effcient code that uses parallel computing. The package supports the users beyond the production of small area estimates. Firstly, tools are provided for exploring the structure of the data and for diagnostic analysis of the model assumptions. Secondly, tools that allow the spatial mapping of the estimates enable the user to create high quality visualizations. Thirdly, results and model summaries can be exported to Excel spreadsheets for further reporting purposes.
    Keywords offcial statistics ; parallel computation ; small area estimation ; visualization
    Language English
    Size 1 Online-Ressource (circa 24 Seiten), Illustrationen
    Publisher Freie Universität Berlin
    Publishing place Berlin
    Document type Book ; Online
    Database ECONomics Information System

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  10. Book ; Online: Robust estimation of economic indicators from survey samples based on Pareto tail modeling

    Alfons, Andreas / Filzmoser, Peter / Templ, Matthias

    (KBI ; 1205)

    2012  

    Author's details Andreas Alfons, Matthias Templ and Peter Filzmoser
    Series title KBI ; 1205
    Language English
    Size Online-Ressource (PDF-Datei: 19 S.), graph. Darst.
    Publisher Katholieke Univ. Leuven, Faculty of Business and Economics
    Publishing place Leuven
    Document type Book ; Online
    Note IMD-Felder maschinell generiert
    Database ECONomics Information System

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