scholarly journals Mapping species richness using opportunistic samples: a case study on ground-floor bryophyte species richness in the Belgian province of Limburg

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Thomas Neyens ◽  
Peter J. Diggle ◽  
Christel Faes ◽  
Natalie Beenaerts ◽  
Tom Artois ◽  
...  
Keyword(s):  
Species Richness ◽  
Process Model ◽  
Cost Effective ◽  
Sampling Bias ◽  
Parameter Estimates ◽  
Multiple Sources ◽  
Ground Floor ◽  
Sampling Process ◽  
Ecological Predictors ◽  
Geostatistical Models

AbstractIn species richness studies, citizen-science surveys where participants make individual decisions regarding sampling strategies provide a cost-effective approach to collect a large amount of data. However, it is unclear to what extent the bias inherent to opportunistically collected samples may invalidate our inferences. Here, we compare spatial predictions of forest ground-floor bryophyte species richness in Limburg (Belgium), based on crowd- and expert-sourced data, where the latter are collected by adhering to a rigorous geographical randomisation and data collection protocol. We develop a log-Gaussian Cox process model to analyse the opportunistic sampling process of the crowd-sourced data and assess its sampling bias. We then fit two geostatistical Poisson models to both data-sets and compare the parameter estimates and species richness predictions. We find that the citizens had a higher propensity for locations that were close to their homes and environmentally more valuable. The estimated effects of ecological predictors and spatial species richness predictions differ strongly between the two geostatistical models. Unknown inconsistencies in the sampling process, such as unreported observer’s effort, and the lack of a hypothesis-driven study protocol can lead to the occurrence of multiple sources of sampling bias, making it difficult, if not impossible, to provide reliable inferences.

Statistical Properties of a DNA Sample Under the Finite-Sites Model

Genetics ◽  
1996 ◽  
Vol 144 (4) ◽  
pp. 1941-1950 ◽  
Author(s):  
Ziheng Yang
Keyword(s):  
Process Model ◽  
Random Mating ◽  
Major Effect ◽  
Statistical Properties ◽  
Parameter Estimates ◽  
Rate Variation ◽  
Markov Process Model ◽  
D Loop ◽  
Infinite Sites Model ◽  
Segregating Sites

Statistical properties of a DNA sample from a random-mating population of constant size are studied under the finite-sites model. It is assumed that there is no migration and no recombination occurs within the locus. A Markov process model is used for nucleotide substitution, allowing for multiple substitutions at a single site. The evolutionary rates among sites are treated as either constant or variable. The general likelihood calculation using numerical integration involves intensive computation and is feasible for three or four sequences only; it may be used for validating approximate algorithms. Methods are developed to approximate the probability distribution of the number of segregating sites in a random sample of n sequences, with either constant or variable substitution rates across sites. Calculations using parameter estimates obtained for human D-loop mitochondrial DNAs show that among-site rate variation has a major effect on the distribution of the number of segregating sites; the distribution under the finite-sites model with variable rates among sites is quite different from that under the infinite-sites model.

scholarly journals Cost-effective surveillance of invasive species using info-gap theory

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yang Liu ◽  
Penghao Wang ◽  
Melissa L. Thomas ◽  
Dan Zheng ◽  
Simon J. McKirdy
Keyword(s):  
Invasive Species ◽  
Native Species ◽  
Cost Effective ◽  
Expert Assessment ◽  
Parameter Estimates ◽  
Model Parameters ◽  
Surveillance Systems ◽  
Effective Manner ◽  
Novel Method ◽  
Population Threshold

AbstractInvasive species can lead to community-level damage to the invaded ecosystem and extinction of native species. Most surveillance systems for the detection of invasive species are developed based on expert assessment, inherently coming with a level of uncertainty. In this research, info-gap decision theory (IGDT) is applied to model and manage such uncertainty. Surveillance of the Asian House Gecko, Hemidactylus frenatus Duméril and Bibron, 1836 on Barrow Island, is used as a case study. Our research provides a novel method for applying IGDT to determine the population threshold ($$K$$ K ) so that the decision can be robust to the deep uncertainty present in model parameters. We further robust-optimize surveillance costs rather than minimize surveillance costs. We demonstrate that increasing the population threshold for detection increases both robustness to the errors in the model parameter estimates, and opportuneness to lower surveillance costs than the accepted maximum budget. This paper provides guidance for decision makers to balance robustness and required surveillance expenditure. IGDT offers a novel method to model and manage the uncertainty prevalent in biodiversity conservation practices and modelling. The method outlined here can be used to design robust surveillance systems for invasive species in a wider context, and to better tackle uncertainty in protection of biodiversity and native species in a cost-effective manner.

scholarly journals Implementasi Multiple Honeypot pada Raspberry Pi dan Visualisasi Log Honeypot Menggunakan ELK Stack

Repositor ◽  
2020 ◽  
Vol 2 (4) ◽  
pp. 475
Author(s):  
Ilfan Arif Romadhan ◽  
Syaifudin Syaifudin ◽  
Denar Regata Akbi
Keyword(s):  
Network Security ◽  
Cost Effective ◽  
Raspberry Pi ◽  
Log Analysis ◽  
Security Threats ◽  
Multiple Sources ◽  
Important Data ◽  
Desktop Computers ◽  
Monitoring Result

ABSTRAKPerlindungan terhadap keamanan jaringan merupakan hal yang sangat penting untuk dilakukan. Mengingat kemudahan dalam mengakses jaringan memungkinkan adanya gangguan dari pihak yang ingin menyerang, merusak, bahkan mengambil data penting. Honeypot memang tidak menyelesaikan masalah pada keamanan jaringan, namun honeypot membuat penelitian tentang serangan menjadi lebih sederhana dengan konsep yang mudah untuk dimengerti dan dimplementasikan. Penelitian ini menerapkan beberapa honeypot menggunakan Raspberry pi dan ELK stack untuk monitoring hasil yang didapatkan oleh honeypot. Tujuan dari penelitian ini untuk merancang sistem yang mampu mendeteksi serangan pada jaringan menggunakan honeypot. Raspberry pi digunakan sebagai sensor honeypot untuk pemantauan ancaman keamanan terbukti hemat biaya dan efektif menggantikan komputer desktop. ELK stack memudahkan pemusatan data dari berbagai sumber dan membuat analisis log yang awalnya rumit untuk dianalisis menjadi lebih menarik.ABSTRACTProtection of network security is very important to do. Given the ease in accessing the network allows for interference from parties who want to attack, destroy, and even retrieve important data. Honeypot does not solve the problem on network security, but the honeypot makes research about attacks become simpler with concepts that are easy to understand and implement. This research applies some honeypot using Raspberry pi and ELK stack for monitoring result obtained by honeypot. The purpose of this research is to design a system capable of detecting attacks on a network using a honeypot. Raspberry pi is used as a honeypot sensor for monitoring proven cost-effective and cost-effective security threats to replace desktop computers. The ELK stack facilitates the convergence of data from multiple sources and makes log analysis initially complex for analysis to be more interesting.

Abstract 17605: Cost-Effectiveness of Contemporary Endovascular Treatment Compared to Open Surgical Revascularization for Cardioembolic Acute Limb Ischemia

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Elizabeth A Genovese ◽  
Kenneth J Smith ◽  
Neal R Barshes ◽  
Michel S Makaroun ◽  
Donald T Baril
Keyword(s):  
Mortality Rate ◽  
Endovascular Treatment ◽  
Cost Effective ◽  
Limb Ischemia ◽  
Morbidity And Mortality ◽  
Adverse Event Rate ◽  
Parameter Estimates ◽  
Acute Limb Ischemia ◽  
Technical Success ◽  
Life Years

Introduction: Treatment of acute limb ischemia (ALI) has a high morbidity and mortality given patients’ multiple comorbidities, poor physiologic reserve, and the need for emergent intervention. Traditionally ALI of embolic origin has been treated with open revascularization (OR), however with increasing experience with thrombolytic therapy and adjuvant techniques, endovascular revascularization (ER) for ALI has become a more common treatment due to the lower associated morbidity and mortality. Hypothesis: Although associated with higher initial costs and lower technical success rates, ER will be cost effective given the decreased adverse event rate and mortality in a frail patient population. Methods: A Markov state-transition model was created to simulate patient oriented outcomes, including technical success, adverse events, limb salvage, discharge facility and quality adjusted life years (QALY) for patients presenting with Rutherford Classification I/IIa/IIb ALI secondary to cardiac embolism. A societal perspective was assumed with a 10-year time horizon. Parameter estimates were derived from published literature and primary data of cardioembolic ALI patients treated at our institution from 2005-2011 with either ER or OR. Costs were adjusted to 2013 U.S. dollars. Results: In the model, OR was technically successful in 87% patients, with a $23,881 cost for the initial hospitalization and a 11.5% perioperative mortality rate; ER was technically successful in 71% of patients, with a $39,619 initial cost, and a 4% mortality rate. At 10 years, the ER strategy cost $92,659/QALY gained compared to OR. Sensitivity analyses demonstrated that ER was favorable at a willingness to pay (WTP) threshold of $100,000/QALY when ER technical success was >70%, initial ER hospitalization cost was <$41,052 or if OR mortality was >10%. At a WTP of $50,000/QALY, ER was cost effective if technical success reached 79%, if ER cost was <$31,287 or if OR mortality was >23%. Conclusions: Contemporary endovascular treatment of cardioembolic ALI carries a greater cost compared to open revascularization, however it is associated with a decreased mortality rate. ER is potentially cost-effective in patients who are at high risk of post-operative mortality following OR.

Cloud Computing for Global Software Development

2015 ◽  
pp. 897-908 ◽  
Author(s):  
Thamer Al-Rousan
Keyword(s):  
Cloud Computing ◽  
Software Development ◽  
Process Model ◽  
Risk Model ◽  
Cost Effective ◽  
Information And Communications Technology ◽  
Global Software Development ◽  
Computing Paradigm ◽  
It Systems ◽  
Computing Platforms

The cloud computing paradigm offers an innovative and promising vision concerning Information and Communications Technology. Actually, it provides the possibility of improving IT systems management and is changing the way in which hardware and software are designed and purchased. This paper introduces challenges in Global Software Development (GSD) and application of cloud computing platforms as a solution to some problems. Even though cloud computing provides compelling benefits and cost-effective options for GSD, new risks and difficulties must be taken into account. Thus, the paper presents a study about the risk issues involved in cloud computing. It highlights the different types of risks and how their existence can affect GSD. It also proposes a new risk management process model. The risk model employs new processes for risk analysis and assessment. Its aim is to analyse cloud risks quantitatively and, consequently, prioritise them according to their impact on different GSD objectives.

scholarly journals DELINEATION OF HOMOGENEOUS ZONES BASED ON GEOSTATISTICAL MODELS ROBUST TO OUTLIERS

2019 ◽  
Vol 32 (2) ◽  
pp. 472-481
Author(s):  
DANILO PEREIRA BARBOSA ◽  
EDUARDO LEONEL BOTTEGA ◽  
DOMINGOS SÁRVIO MAGALHÃES VALENTE ◽  
NERILSON TERRA SANTOS ◽  
WELLINGTON DONIZETE GUIMARÃES
Keyword(s):  
Linear Models ◽  
Information Criterion ◽  
Physicochemical Characteristics ◽  
Parameter Estimates ◽  
Mixed Linear Models ◽  
Management Zones ◽  
Geostatistical Models ◽  
Apparent Electrical Conductivity ◽  
External Drift ◽  
Theory And Model

ABSTRACT Measures of the apparent electrical conductivity (ECa) of soil are used in many studies as indicators of spatial variability in physicochemical characteristics of production fields. Based on these measures, management zones (MZs) are delineated to improve agricultural management. However, these measures include outliers. The presence or incorrect identification and exclusion of outliers affect the variogram function and result in unreliable parameter estimates. Thus, the aim of this study was to model ECa data with outliers using methods based on robust approximation theory and model-based geostatistics to delineate MZs. Robust estimators developed by Cressie-Hawkins, Genton and MAD Dowd were tested. The Cressie-Hawkins semivariance estimator was selected, followed by the semivariogram cubic fit using Akaike information criterion (AIC). The robust kriging with an external drift plug-in was applied to fitted estimates, and the fuzzy k-means classifier was applied to the resulting ECa kriging map. Models with multiple MZs were evaluated using fuzzy k-means, and a map with two MZs was selected based on the fuzzy performance index (FPI), modified partition entropy (MPE) and Fukuyama-Sugeno and Xie-Beni indices. The defined MZs were validated based on differences between the ECa means using mixed linear models. The independent errors model was chosen for validation based on its AIC value. Thus, the results demonstrate that it is possible to delineate an MZ map without outlier exclusion, evidencing the efficacy of this methodology.

scholarly journals Employment of Active Learning at HEIs in Bangladesh to Improve Education Quality

2016 ◽  
Vol 9 (10) ◽  
pp. 47 ◽  
Author(s):  
Faieza Chowdhury
Keyword(s):  
Active Learning ◽  
Learning Strategies ◽  
Resource Constraints ◽  
Implementation Process ◽  
Cost Effective ◽  
Education Quality ◽  
Quality Of Education ◽  
Multiple Sources ◽  
Active Learning Strategies

<p class="apa">In recent years, education quality and quality assessment have received a great deal of attention at Higher Education Institutions (HEIs) in Bangladesh. Most of the HEIs in Bangladesh face severe resource constraints and find it difficult to improve education quality by improving inputs, such as better infrastructure and modernized classroom facilities. Thus, in response to the present government’s demand to improve the quality of education at HEIs in Bangladesh, it is imperative to formulate plans that are more cost-effective. According to some previous studies, the quality of education depends largely on the teaching-learning process. These studies affirm that, with limited resources at hand, the employment of active learning in the classroom is one of the most effective ways to improve education quality. To conduct this qualitative research, we utilized multiple sources of data, including semi-structured and in-depth interviews, descriptive observations and self-administered questionnaires. This paper aims to explore three related issues: What are the various active learning strategies that can be employed by the instructors at HEIs in Bangladesh? What are the potential factors that can hinder the implementation process? Finally, what recommendations can be provided on how to successfully implement active learning strategies in the classroom? The findings suggest that a lack of teacher training and student prior experience in an active learning environment, large class sizes, excessive curriculum loads and students’ academic backgrounds are some common factors that can hinder the implementation of active learning in Bangladesh. The findings of this study can be instrumental for HEIs in Bangladesh as they aspire to improve their education quality.</p>

Community Health Workers (CHWs) as Innovators

2018 ◽  
Vol 13 (1) ◽  
pp. 15-28
Author(s):  
Tyler Prentiss ◽  
John Zervos ◽  
Mohan Tanniru ◽  
Joseph Tan
Keyword(s):  
Community Health ◽  
Community Health Workers ◽  
Health Workers ◽  
Underserved Populations ◽  
Low Cost ◽  
Cost Effective ◽  
Well Being ◽  
Grant Writing ◽  
Multiple Sources ◽  
Context Of Learning

Community health workers (CHWs) have a longstanding role in improving the health and well-being of underserved populations in resource-limited settings. CHWs are trusted in the communities they serve and are often able to see through solutions on community challenges that outside persons cannot. Notwithstanding, such solutions often must be low-cost, easily implementable, and permit knowledge gaps among CHWs to be filled via appropriate training. In this sense, use of cost-effective information technology (IT) solutions can be key to increasing access to knowledge for these community agents. This paper highlights insights gleaned from a pilot study performed in Detroit, Michigan with a group of CHWs in basic grant-writing training via an e-platform, the Community Health Innovator Program (CHIP). The results are discussed within the context of learning theory. It is concluded that e-platforms are necessary for CHWs to leverage knowledge from multiple sources in an adaptive environment towards addressing ever-evolving global health challenges.

Bayesian Modelling for Machine Learning

2005 ◽  
pp. 236-242
Author(s):  
Paul Rippon ◽  
Kerrie Mengersen
Keyword(s):  
Machine Learning ◽  
Process Model ◽  
Bayesian Learning ◽  
Data Sets ◽  
Complex Data ◽  
Sources Of Information ◽  
Multiple Sources ◽  
Complex Data Sets ◽  
Complex Phenomena ◽  
Learning Data

Learning algorithms are central to pattern recognition, artificial intelligence, machine learning, data mining, and statistical learning. The term often implies analysis of large and complex data sets with minimal human intervention. Bayesian learning has been variously described as a method of updating opinion based on new experience, updating parameters of a process model based on data, modelling and analysis of complex phenomena using multiple sources of information, posterior probabilistic expectation, and so on. In all of these guises, it has exploded in popularity over recent years.

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