Using statistical inverse methods for detecting defects in electronic components

The thermal modeling of electronic components is mandatory to optimize the cooling design versus reliability. Indeed most of failures are due to thermal phenomena [1]. Some of them are neglected or omitted by lack of data: ageing, manufacturing issues like voids in glue or solder joints, or material properties variability. Transient measurements of the junction-to-board temperature supply real thermal behavior of the component and PCB assembly to complete these missing data[2]. To complement and supplement the numerical model, inverse methods identification based on a statistical deconvolution approach, such as Bayesian one, is applied on these measurements to extract a Foster RC thermal network. The identification algorithm performances have been demonstrated on numerical as well as experimental dataset. Furthermore defects or voids can be detected using the extracted Foster RC networks.

Evaluation of the potential for transmission of coronavirus disease via saliva

Aim: One of the main factors that play a pivotal role in the transmission of COVID-19 from human to human is saliva; according to the subject’s importance, the present study aimed to evaluate the potential of transmission via the saliva of coronavirus disease. Methods: PubMed, ISI, Embase, Scopus, Medicine have been used until September 2020 to search for articles. Therefore, EndNote X9 used to manage electronic resources. A 95% confidence interval (CI) effect size, fixed effect model, Inverse-variance methods have been calculated. The positive rate of SARS-CoV2 assessed with meta analysis. To deal with potential heterogeneity, random effects were used, and I2 showed heterogeneity. I2 values above 50% signified moderate-to-high heterogeneity. The Meta-analysis has been evaluated with Stata/MP v.16 (the fastest version of Stata) statistical software. Results: According to the study’s purpose, in the initial search with keywords, 19 articles were found, the full text of 3 studies was reviewed, and finally, three studies were selected. The positive rate of SARS-CoV2 was 86% (86%; 95% CI 67 %-100%). Conclusion: saliva can be a non-invasive specimen type for diagnosis of COVID-19. Dentists should be aware that saliva plays a major role in the transmission of COVID-19 from human to human, and failure to follow prevention protocols can contaminate them.

Obesity as a predictor for adverse outcomes among COVID-19 patients: A meta-analysis

BackgroundThis meta-analysis sought to determine the estimated association between obesity and adverse outcomes among COVID-19 patients.MethodsWe followed the recommended PRISMA guidelines. A systematic literature search was conducted in PubMed, Google Scholar, and ScienceDirect for published literature between December 1, 2019, and October 2, 2020. The data for the study were pooled from studies that contained the search terms “Obesity” AND (COVID-19 or 2019-nCoV or Coronavirus or SARS-CoV-2) AND (“ICU admission” OR “Hospitalization” OR “Disease severity” OR “Invasive mechanical ventilator” OR “Death” OR “Mortality”). All the online searches were supplemented by reference screening of retrieved studies for additional literature. The pooled odds ratio (OR) and confidence intervals (CI) from the retrieved studies were calculated using the random effect model (Inverse-Variance method).FindingsFive studies with a combined sample size of 335,192 patients were included in the meta-analysis. The pooled OR from the final analysis showed that patients who are severely obese were more likely to experience adverse outcome (death or ICU admission or needing IMV or hospitalization) compared to the normal patients [OR = 2.81, 95% CI = 2.33 – 3.40, I2 = 29%].ConclusionSevere obesity is a risk factor in developing adverse outcomes among COVID-19 patients. The finding of the study signifies promotive, preventive, and curative attention to be accorded patients diagnosed with severe obesity and COVID-19.

Obesity as a Predictor for Adverse Outcomes Among COVID-19 Patients: A Meta-Analysis

Background: The 2019 Severe Acute Respiratory Syndrome Coronavirus (COVID-19) is an unexpected pandemic causing mortalities across all ages. However, the severity of its health implications is mostly reported in persons with chronic health conditions with obesity being identified as one of the leading predisposing factors in acquiring the novel virus and developing its adverse complications. This meta-analysis sought to determine the estimated association between obesity and adverse outcomes among COVID-19 patients. Methods: We followed the recommended PRISMA guidelines in executing this study. A systematic literature search was conducted in PubMed, Google Scholar, and ScienceDirect for published literature between December 1, 2019, and October 2, 2020. The data for the study were pooled from studies that contained the search terms "Obesity" AND (COVID-19 or 2019-nCoV or Coronavirus or SARS-CoV-2) AND ("ICU admission" OR "Hospitalization" OR "Disease severity" OR "Invasive mechanical ventilator" OR "Death" OR "Mortality"). All the online searches were supplemented by reference screening of retrieved studies for additional literature. The pooled odds ratio (OR) and confidence intervals (CI) from the retrieved studies were calculated using the random effect model (Inverse-Variance method). Findings: A total of five (5) studies with a combined sample size of 335,192 patients were included in the meta-analysis. The pooled OR from the final analysis showed that patients who are severely obese were more likely to experience adverse outcome (death or ICU admission or needing IMV or hospitalization) compared to the normal patients [OR = 2.81, 95% CI = 2.33 – 3.40, I2 = 29%].Conclusion: Severe obesity is a risk factor in developing adverse outcomes among COVID-19 patients. The finding of the study signifies promotive, preventive, and curative attention to be accorded patients diagnosed with severe obesity and COVID-19.

Technology for constructing a 3D density model of the earth's crust in the INTEGRO GIS

The work is devoted to the construction of a three-dimensional density model of the territory, which would not contradict the information obtained by other methods (drilling, seismic, etc.). A generalized scheme for constructing such a model is given, its stages and ways of matching with the results of other methods are described. The technology described in the work is based on the tools included in the GIS INTEGRO software package (FSBI "VNIGNI"). The article is illustrated with examples of the technology application in the construction of density models for various parts of the Volga-Ural oil and gas province. Key words: density modeling, 3D density model, inverse problem of gravity exploration, GIS INTEGRO.

Surface modelling by geoid determination for flood control of Ewekoro limestone deposit (Nigeria)

Purpose. To determine the geoid heights from various control points of the quarry located in the northern and southern zones of the limestone deposit of the Lafarge WAPCO Cement Ewekoro in Ogun State, Nigeria. Methodology. The GPS and levelling data were used to determine the geoid heights from various control points of the quarry located in the northern and southern zones of the limestone deposit. The geoid heights obtained from GPS-Levelling data were used for three surface models which are polynomial regression model, inverse distance model and nearest neighbour model. These models were used to crossvalidate the geoid heights for the control points. Findings. The result shows that the deviations of the geoid heights for the GPS/Levelling and models are between 0.03 and 0.01m respectively. The models were used to generate contour maps that reveal the better location where the flood can be channelled. Originality. The results can be compared to the data obtainable during operations carried out in the quarry. Practical value. The flood in the quarry face will be better controlled by creating a sump at the lowest point on the elevation maps and controlled drilling to give better aeration.

Suitable Site Selection for Rainwater Harvesting and Storage Case Study Using Dohuk Governorate

The Middle East is an inherently dry zone. It has experienced severe drought for the last seven years, and climate change has made the situation worse. The Dohuk governorate has been suffering from an appalling water crisis. One possible way of relieving this water crisis is by properly harvesting the rainwater. Rainwater harvesting is a widely used method of storing rainwater in the countries presenting with drought characteristics. Several pieces of research have derived and developed different criteria and techniques to select suitable sites for harvesting rainwater. The main aim of this research was to identify and select suitable sites for the potential erection of dams, as well as to derive a model builder in ArcMap 10.4.1. The model combined several parameters, such as slope, runoff potential, land cover/use, stream order, soil quality, and hydrology to determine the suitability of the site for harvesting rainwater. To compute the land use/cover categories, the study depended on Landsat image data from 2018. Supervised classification was applied using the ENVI 5 software, while the slope mapping and drainage order were extracted using a digital elevation model. Inverse distance weighting (IDW) was used for the spatial interpolation of the rain data. The results demonstrated that suitable areas for water harvesting, are located in the middle and northern part of the research area, and in intensively cultivated zones. The main soil texture in these suitable sites was loam, while the rainfall rate amounted to 750 to 900 mm. This research shows that 15% and 13% of the area studied can be categorized as having excellent and good suitability for water harvesting, respectively. Furthermore, 21% and 27% of the area studied were of moderate and poor suitability, while the remaining 24% were not suitable at all.

PERTUMBUHAN, MORTALITAS DAN TINGKAT PEMANFAATAN KERANG POKEA (Batissa violacea var. celebensis von Martens, 1897) DI SUNGAI LAEYA KONAWE SELATAN PROVINSI SULAWESI TENGGARA

: Pokea clam are one of the potential resources and have an important role both ecologically and economically. One of areas suitable for the life of this clam is the laeya river. This research aimed to determine growth, mortality and eksploitation rate of Pokea clam on the Laeya River in South Konawe which was started in September 2016 – February 2017. This research used swept area method by using a catching tool namely tangge. Data were growth, mortality and the exploitation level was analysed using Bhattacharya method, inverse von Bertalanffy, width converted catch curve and empirical Pauly, accommodated in FiSAT II version 3.0. The total sample of pokea clam during the research were 849 individuals. The result of growth analysis showed that the asymptotic width value (L∞), growth constant (K), estimated value t0 for the growth of pokea clam was 7,41, 0,56 and -0,38. The result of estimation analysis for the level of morality showed that the natural mortality value (M) was 1,84, the catching mortality (F) was 1,19, and the total mortality (Z) was 3,03. The exploitation rate (E) was 0,39 which shows the level exploitation rate of pokea clam in the waters of the Laeya River was still relatively low (under fishing). Keywords : Pokea Clam, Laeya Rivers, Growth, Mortality, Exploitation Rate Abstrak : Kerang pokea merupakan salah satu sumberdaya potensial dan mempunyai peranan penting baik secara ekologis maupun ekonomis. Salah satu wilayah yang cocok untuk kehidupan kerang ini adalah Sungai Laeya. Penelitian ini bertujuan untuk mengetahui pertumbuhan, mortalitas dan tingkat pemanfaatan kerang pokea di Sungai Laeya Konawe Selatan yang dimulai pada bulan September 2016 – Februari 2017. Metode penelitian yang digunakan adalah luas sapuan (swept area method) dengan memakai alat tangkap tangge. Data pertumbuhan, mortalitas dan tingkat eksploitasi masing-masing menggunakan metode Bhattacharya, model inverse von Bertalanffy, hasil tangkapan yang dikonversi dari data lebar cangkang dan empiris Pauly yang terakomodasi dalam program FiSAT II versi 3.0. Total sampel kerang pokea selama penelitian sebesar 849 individu. Hasil analisis pertumbuhan menunjukan nilai lebar asimtotik (L∞), konstanta pertumbuhan (K), nilai dugaan t0 pada pertumbuhan kerang pokea masing-masing 7,41, 0,56, dan -0,38. Hasil analisis pendugaan tingkat mortalitas menunjukkan nilai mortalitas alami (M) 1,84, mortalitas penangkapan (F) 1,19, dan mortalitas total (Z) 3,03. Tingkat eksploitasi (E) yaitu 0,39 yang menunjukkan tingkat eksploitasi kerang pokea di perairan Sungai Laeya masih tergolong rendah (under fishing). Kata Kunci : Kerang Pokea, Sungai Laeya, Pertumbuhan, Mortalitas, Tingkat Eksploitasi

Feedforward model-inverse position control of three-stage servo-valve using zero magnitude error tracking control

Three-stage servo-valves are popularly used in hydraulic systems that require large flow rate and high pressure. For a proper control of flow direction and flow rate fed into a hydraulic actuator, securing a proper position control bandwidth is a critical task for the servo-valve. In this paper, a set of popular control methods are systematically studied and a control method is selected. It is proven that the feedforward model-inverse control is the most effective method in terms of the control bandwidth. In the present work, the feedforward closed-loop architecture is adopted and the closed-loop system is estimated in a linear discrete-time transfer function by recursive least squares method. On recognizing a nonminimum phase zero problem, this work implements the zero magnitude error tracking control, an approximate model-inverse technique, in order to overcome the problem. As a result, the effectiveness of the proposed feedforward model-inverse position control strategy is verified.