scholarly journals Vector and Triangular Representations of Project Estimation Uncertainty: Effect of Gender on Usability

Author(s):  
Dorota Kuchta ◽  
Jerzy Grobelny ◽  
Rafał Michalski ◽  
Jan Schneider
2019 ◽  
pp. 57-63
Author(s):  
M. A. Artyukhova ◽  
S. N. Polesskiy

Human activity is often accompanied by exposure of ionizing radiation: the exploitation of space systems and power plants, research using isotopic sources, medicine. The development of electronic equipment is regulated by carrying out activities to ensure the required reliability and radiation resistance. However, the effect of ionizing radiation on reliability indicators is not taken into account properly, or is not taken into account at all, that sometimes leads to the loss of expensive equipment and even to human victims. The article discusses the methodology for carrying out an adequate estimate of the reliability considering the influence of external influencing factors, including ionizing radiation. The timeliness of decisions making to ensure the required reliability indicators is determined by the completeness of the reliability estimation at the design stage. Effort to ensure the reliability and durability of devices after the design stage is not economically viable. The completeness and adequacy of the estimation always depends on the interaction of specialists in different fields: designers, programmers, experts in the field of circuit design, electrical engineering and experts in the field of reliability and radiation resistance.


Electronics ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1195
Author(s):  
Priya Varshini A G ◽  
Anitha Kumari K ◽  
Vijayakumar Varadarajan

Software Project Estimation is a challenging and important activity in developing software projects. Software Project Estimation includes Software Time Estimation, Software Resource Estimation, Software Cost Estimation, and Software Effort Estimation. Software Effort Estimation focuses on predicting the number of hours of work (effort in terms of person-hours or person-months) required to develop or maintain a software application. It is difficult to forecast effort during the initial stages of software development. Various machine learning and deep learning models have been developed to predict the effort estimation. In this paper, single model approaches and ensemble approaches were considered for estimation. Ensemble techniques are the combination of several single models. Ensemble techniques considered for estimation were averaging, weighted averaging, bagging, boosting, and stacking. Various stacking models considered and evaluated were stacking using a generalized linear model, stacking using decision tree, stacking using a support vector machine, and stacking using random forest. Datasets considered for estimation were Albrecht, China, Desharnais, Kemerer, Kitchenham, Maxwell, and Cocomo81. Evaluation measures used were mean absolute error, root mean squared error, and R-squared. The results proved that the proposed stacking using random forest provides the best results compared with single model approaches using the machine or deep learning algorithms and other ensemble techniques.


2019 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
James Prater ◽  
Konstantinos Kirytopoulos ◽  
Tony Ma

Purpose Despite the advent of sophisticated control methods, there are still significant issues regarding late delivery of information technology projects. The purpose of this paper is to investigate the common causes of scheduling problems specifically in the information technology projects context. Design/methodology/approach Through a quantitative research, the importance of those causes, as well as the underpinning factors driving them, is explored. The causes are ranked according to their relative important index, and exploratory factor analysis is employed to reveal underlying dimensions (factors) of these causes. Findings From the analysis, four factors were extracted, namely, “Dataless Newbie,” “Technical Newbie,” “Pragmatic Futurist” and “Optimistic Politician.” These factors explain the different latent conditions that lead to scheduling problems in information technology projects. Practical implications The key contribution of this research is that it enlightens the latent conditions underpinning scheduling problems. Also, the evidence provides that schedule development for information technology projects is impacted by the same causes that impact engineering projects, and that applying a number of mitigation techniques widely used within the engineering area, such as reference class, would, no doubt, not only improve information technology schedules but also reduce the political pressures on the project manager. Originality/value This research provides a valuable insight into understanding the underlying factors for poor project estimation.


2021 ◽  
Vol 13 (8) ◽  
pp. 1592
Author(s):  
Nikolai Knapp ◽  
Andreas Huth ◽  
Rico Fischer

The estimation of forest biomass by remote sensing is constrained by different uncertainties. An important source of uncertainty is the border effect, as tree crowns are not constrained by plot borders. Lidar remote sensing systems record the canopy height within a certain area, while the ground-truth is commonly the aboveground biomass of inventory trees geolocated at their stem positions. Hence, tree crowns reaching out of or into the observed area are contributing to the uncertainty in canopy-height–based biomass estimation. In this study, forest inventory data and simulations of a tropical rainforest’s canopy were used to quantify the amount of incoming and outgoing canopy volume and surface at different plot sizes (10, 20, 50, and 100 m). This was performed with a bottom-up approach entirely based on forest inventory data and allometric relationships, from which idealized lidar canopy heights were simulated by representing the forest canopy as a 3D voxel space. In this voxel space, the position of each voxel is known, and it is also known to which tree each voxel belongs and where the stem of this tree is located. This knowledge was used to analyze the role of incoming and outgoing crowns. The contribution of the border effects to the biomass estimation uncertainty was quantified for the case of small-footprint lidar (a simulated canopy height model, CHM) and large-footprint lidar (simulated waveforms with footprint sizes of 23 and 65 m, corresponding to the GEDI and ICESat GLAS sensors). A strong effect of spatial scale was found: e.g., for 20-m plots, on average, 16% of the CHM surface belonged to trees located outside of the plots, while for 100-m plots this incoming CHM fraction was only 3%. The border effects accounted for 40% of the biomass estimation uncertainty at the 20-m scale, but had no contribution at the 100-m scale. For GEDI- and GLAS-based biomass estimates, the contributions of border effects were 23% and 6%, respectively. This study presents a novel approach for disentangling the sources of uncertainty in the remote sensing of forest structures using virtual canopy modeling.


Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1581
Author(s):  
Mohamed Alkassem Alosman ◽  
Stéphane Ruy ◽  
Samuel Buis ◽  
Patrice Lecharpentier ◽  
Jean Bader ◽  
...  

Surface irrigation is known as a highly water-consuming system and needs to be optimized to save water. Models can be used for this purpose but require soil parameters at the field scale. This paper aims to estimate effective soil parameters by combining: (i) a surface flow-infiltration model, namely CALHY; (ii) an automatic fitting algorithm based on the SIMPLEX method; and (iii) easily accessible and measurable data, some of which had never been used in such a process, thus minimizing parameter estimation errors. The validation of the proposed approach was performed through three successive steps: (1) examine the physical meaning of the fitted parameters; (2) verify the accuracy of the proposed approach using data that had not been served in the fitting process; and (3) validate using data obtained from independent irrigation events. Three parameters were estimated with a low uncertainty: the saturated hydraulic conductivity Ks, the hydraulic roughness k, and the soil water depletion ∆θ. The estimation uncertainty of the soil surface depressional storage parameter H0 was of the same order of magnitude of its value. All experimental datasets were simulated very well. Performance criteria were similar during both the fitting and validation stages.


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