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Author(s):  
DAVID E. ALLEN ◽  
MICHAEL MCALEER

This paper features a statistical analysis of the monthly three factor Fama/French return series. Rolling OLS regressions explore the relationship between the 3 factors, using data from July 1926 to June 2018, available on French’s website. The results suggest there are significant and time-varying relationships between the factors. A sub-sample from July 1990 to July 2018 is used to analyze the three series using two-stage least squares and the Hausman test to check for issues related to endogeneity. The empirical results suggest that the factors, when combined in OLS regression analysis, as suggested by Fama and French (2018), are likely to suffer from endogeneity. Ramsey’s RESET tests suggest a nonlinear relationship exists between the three series. We use two instruments to estimate the market betas, and compare them to betas estimated not using instruments. Non-parametric tests of the two sets of betas suggest significant differences. The results suggest that using these factors in linear regression analysis, as recommended by Fama and French [(2018). Choosing factors. Journal of Financial Economics, 128(2), 234–252] is problematic in that the estimated coefficients are highly sensitive to the correct model specification.


Author(s):  
Martin Weinmann ◽  
Sven Wursthorn ◽  
Michael Weinmann ◽  
Patrick Hübner

AbstractThe Microsoft HoloLens is a head-worn mobile augmented reality device. It allows a real-time 3D mapping of its direct environment and a self-localisation within the acquired 3D data. Both aspects are essential for robustly augmenting the local environment around the user with virtual contents and for the robust interaction of the user with virtual objects. Although not primarily designed as an indoor mapping device, the Microsoft HoloLens has a high potential for an efficient and comfortable mapping of both room-scale and building-scale indoor environments. In this paper, we provide a survey on the capabilities of the Microsoft HoloLens (Version 1) for the efficient 3D mapping and modelling of indoor scenes. More specifically, we focus on its capabilities regarding the localisation (in terms of pose estimation) within indoor environments and the spatial mapping of indoor environments. While the Microsoft HoloLens can certainly not compete in providing highly accurate 3D data like laser scanners, we demonstrate that the acquired data provides sufficient accuracy for a subsequent standard rule-based reconstruction of a semantically enriched and topologically correct model of an indoor scene from the acquired data. Furthermore, we provide a discussion with respect to the robustness of standard handcrafted geometric features extracted from data acquired with the Microsoft HoloLens and typically used for a subsequent learning-based semantic segmentation.


2021 ◽  
Vol 108 (Supplement_7) ◽  
Author(s):  
Ishita Handa ◽  
Katherine Pearson ◽  
Anne Marie Day ◽  
James Kirkby-Bott ◽  
David Berry

Abstract Aims Service provision and assessing the impact of future innovations can best be assessed by accurate reproducible data collection. The traditional model for our ambulatory surgical clinic with ultrasound allowed booking directly from the Emergency Department (ED) without discussion with the Surgical Team. We questioned whether this was the correct model and changed to a model of discussion with the Surgical team before booking in an effort to better utilise resource and reduce unnecessary footfall in the hospital. Methods We reviewed the outcome data of consecutive ambulatory ultrasound clinic referrals before and after implementation of this change in practice (1 month before and after the change) Results Ninety four ambulatory Ultrasound referrals were reviewed. In the first cohort 30 of 50 patients came directly from ED without discussion. A positive USS report was recorded in 8 of the 30 (27% USS positivity rate).  After the change in practice to discuss with the surgical team, 11 of 43 patients originated primarily from ED with a positive finding in 4 patients (36%). Conclusions A key aim of service improvement is to optimise / improve utilisation of resource. This must be achieved without missing pathology. In this study we reduced the number of scans performed by ED whilst increasing the likelihood of a positive scan. This change in practice better utilised resource and reduced unnecessary footfall in the hospital.


2021 ◽  
pp. 11-11
Author(s):  
V. Chabaniuk ◽  
◽  
O. Dyshlyk ◽  

The actual, feasible and simultaneously "correct" models of digital NSDI of Ukraine are considered in the work. A model of the existed digital NSDI system of Ukraine is named “actual”. This model already differs from the model defined by the [1]. As the latter is unlikely to be implemented in the near future, the issue of the digital feasible NSDI model of Ukraine in the next five years, which would take into account the actual model, is especially acute. In addition to feasibility, such a model must also be "correct", what is proposed in the article. The correct is called a model, the truth of which can be established by inductive or deductive reasoning. To do this, the correct model must be formalized enough so that everyone can verify the authors’ reasoning independently. Understanding both actual and correct models of NSDI of Ukraine will help to properly organize and develop actual Spatial Infrastructure Activities (SpIA) in Ukraine, including the real[1] implementation of the [1]. Although the results of the article call into question its feasibility and substantiate an alternative viewpoint on the automation problem of NGDI/NSDI/SpIA. However, we are convinced that it is still possible to change the alternative viewpoint to a cooperative one, if by means of by-laws the models of NGDI (Law), NSDI (article) and, finally, SpIA are agreed upon To prove the "correctness" of the feasible NSDI model, the theory of Relational cartography and its two main methods are used: Conceptual Frameworks and Solution Frameworks. In addition, the correspondence between Relational cartography and Model-Based Engineering is used. Key words: NSDI; product model; process model; actual, feasible and «correct» model. [1] Real. 1. Which exists in reality, true. Is used with: reality, life, existence, conditions, circumstances, fact, danger, force, wages, income. 2. One that can be implemented, executed: a real plan, a real program, a real task, a real deadline. 3. Which is based on taking into account and assessing the real conditions of reality: a real approach, a real view, a real policy.- accessed 2021-feb-14, http://slovopedia.org.ua/32/53408/32016.html (Ukrainian).


Author(s):  
Andreia Chapouto

AbstractWe study the well-posedness of the complex-valued modified Korteweg-de Vries equation (mKdV) on the circle at low regularity. In our previous work (2021), we introduced the second renormalized mKdV equation, based on the conservation of momentum, which we proposed as the correct model to study the complex-valued mKdV outside $$H^\frac{1}{2}({\mathbb {T}})$$ H 1 2 ( T ) . Here, we employ the method introduced by Deng et al. (Commun Math Phys 384(1):1061–1107, 2021) to prove local well-posedness of the second renormalized mKdV equation in the Fourier–Lebesgue spaces $${\mathcal {F}}L^{s,p}({\mathbb {T}})$$ F L s , p ( T ) for $$s\ge \frac{1}{2}$$ s ≥ 1 2 and $$1\le p <\infty $$ 1 ≤ p < ∞ . As a byproduct of this well-posedness result, we show ill-posedness of the complex-valued mKdV without the second renormalization for initial data in these Fourier–Lebesgue spaces with infinite momentum.


2021 ◽  
Author(s):  
Yadigar GÜLSEVEN SIDIR ◽  
İsa SIDIR

Abstract In this study, some electronic, hydrophobic and termochemical parameters of 28 different 5,8-quinolinequinones derivatives having diversity substituents have been calculated by using DFT (B3LYP) / 6-31G (d, p) method and basis set. Relationships between different molecular descriptives have been studied with used like molecular polarizability (α), dipole moment (μ), EHOMO, ELUMO, molecular volume (Vm), ionization potential (IP), electron affinity (EA), electronegativity (χ), molecular hardness (η), molecular softness (S), electrophilic index (Ꞷ), molar refractivity (MR), octanol–water partition coefficient (logP), thermochemical properties (entropy (Se), capacity of heat (C)); as to investigate activity relationships with molecular structure. In addition, The QSAR/QSPR between molecular properties and biological activity (Anti-proliferative and Anti-inflammatory activity) has investigated, where R, R2, F and P have taken into account in order to find a statistically correct model in QSAR studies. The dependence of the electronegative parameter on both electronic and thermochemical parameters was the most correlated parameter.


2021 ◽  
Vol 9 (7) ◽  
pp. 77
Author(s):  
Mats Sjöström ◽  
Malin Brundin

Local anaesthesia is taught early in the practical part of dental programs. However, dental students express uncertainty and concern before their practical training in local anaesthesia. The aim of this study was to evaluate how extra educational elements in the teaching of local anaesthesia affect students’ confidence using local anaesthesia. The students were divided into three groups (A, B and C). Group A received the same education that was used the previous year (i.e., four hours of theoretical lectures followed by four hours of practical exercises performed on a fellow student). Group B did their practical training on fellow students in groups of three, with each student taking turns performing, receiving and observing the procedure. Group C received training using an anatomically correct model before their practical training on a fellow student. After each training step, the students completed a questionnaire about their confidence administering local anaesthesia. The students experienced a significant increase in confidence after each educational step. Combining theory and practical instruction, including the use of anatomically correct models and peer instruction, improved students’ confidence in administering local anaesthesia. The greatest increase in confidence was in the students placed in groups of three where each student performed, received and observed the procedure.


Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3624
Author(s):  
Jiarui Wang ◽  
Hannah Lindley-Hatcher ◽  
Xuequan Chen ◽  
Emma Pickwell-MacPherson

The non-ionizing and non-invasive nature of THz radiation, combined with its high sensitivity to water, has made THz imaging and spectroscopy highly attractive for in vivo biomedical applications for many years. Among them, the skin is primarily investigated due to the short penetration depth of THz waves caused by the high attenuation by water in biological samples. However, a complete model of skin describing the THz–skin interaction is still needed. This is also fundamental to reveal the optical properties of the skin from the measured THz spectrum. It is crucial that the correct model is used, not just to ensure compatibility between different works, but more importantly to ensure the reliability of the data and conclusions. Therefore, in this review, we summarize the models applied to skin used in the THz regime, and we compare their adaptability, accuracy, and limitations. We show that most of the models attempt to extract the hydration profile inside the skin while there is also the anisotropic model that displays skin structural changes in the stratum corneum.


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