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Demonstrating grating-based phase-contrast imaging of laser-driven shock waves

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Matter and Radiation at Extremes 2024年第4期9卷 90-97页

作者： Leonard Wegert Stephan Schreiner Constantin Rauch Bruno Albertazzi Paulina Bleuel eric Frojdh michel Koenig Veronika Ludwig Artem SMartynenko Pascal Meyer Aldo Mozzanica Michael Müller Paul Neumayer Markus Schneider Angelos Triantafyllidis Bernhard Zielbauer Gisela Anton Thilo michel Stefan Funk Plasma Physics Department GSI Helmholtzzentrum fur SchwerionenforschungPlanckstraBe 164291 DarmstadtGermany Erlangen Centre for Astroparticle Physics(ECAP) Friedrich-Alexander-Universität Erlangen-NurnbergNikolaus-Fiebiger-StraBe 291058 ErlangenGermany LULI-CNRS CEASorbonne UniversitésEcole PolytechniqueInstitut Polytechnique de ParisF-91120 Palaiseau CedexFrance Paul Scherrer Institut(Psi) Forschungsstrasse 1115232VilligenSwitzerland Karlsruhe Institute of Technology Institute of Microstructure TechnologyHermann-von-Helmholtz-Platz 176344 Eggenstein-LeopoldshafenGermany

Single-shot X-ray phase-contrast imaging is used to take high-resolution images of laser-driven strong shock *** a two-grating Talbot interferometer,we successfully acquire standard absorption,differential phase-contrast,and dark-field images of the shocked *** agreement is demonstrated between experimental data and the results of two-dimensional radiation hydrodynamics simulations of the laser-plasma *** main sources of image noise are identified through a thorough assessment of the interferometer’s *** acquired images demonstrate that grating-based phase-contrast imaging is a powerful diagnostic tool for high-energy-density *** addition,we make a novel attempt at using the dark-field image as a signal modality of Talbot interferometry to identify the microstructure of a foam target.

关键词： interaction shock phase

New Ecg Signal Compression Model Based on Set Theory Applied to Images

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Journal of Computer and Communications 2023年第8期11卷 29-43页

作者： Ivan Basile Kabiena eric.michel deussom djomadji Emmanuel Tonye Department of Computer Engineering and Telecommunications National Advanced School of Engineering University of Douala Douala Cameroon Department of Electrical and Electronic Engineering College of Technology University of Buea Buea Cameroon Department of Electrical and Telecommunications Engineering National Advanced School of Engineering of Yaounde University of Yaounde I Yaounde Cameroon

Cardiovascular diseases are the origin of many causes of death worldwide. They impose on practitioners optimal diagnostic methods such as telemedicine in order to be able to quickly detect anomalies for daily care and monitoring of patients. The Electrocardiogram (ECG) is an examination that can detect abnormal functioning of the heart and generates a large number of digital data which can be stored or transmitted for further analysis. For storage or transmission purposes, one of the challenges is to reduce the space occupied by ECG signal and for that, it is important to offer more and more efficient algorithms capable of achieving high compression rates, while offering a good quality of reconstruction in a relatively short time. We propose in this paper a new ECG compression scheme that is based on a subset of signal splitting and 2D processing, the wavelet transform (DWT) and SPIHT coding which has proved their worth in the field of signal processing and compression. They are exploited for decorrelation and coding of the signal. The results obtained are significant and offer many perspectives.

关键词： Compression ECG DWT Sub-Set 2D

Propagation Model Optimization Based on Ion Motion Optimization Algorithm for Efficient Deployment of eLTE Network

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Journal of Computer and Communications 2022年第11期10卷 171-196页

作者： deussom djomadji eric.michel Tsague Njatsa Austene Beldine Tonye Emmanuel Department of Electrical and Electronic Engineering College of Technology University of Buea Buea Cameroon Division of Information and Communications Technology NASPT University of Yaoundé I Yaoundé Cameroon Department of Electrical and Telecommunications University of Yaoundé I Yaoundé Cameroon

Propagation models are the foundation for radio planning in mobile networks. They are widely used during feasibility studies and initial network deployment, or during network extensions, particularly in new cities. They can be used to calculate the power of the signal received by a mobile terminal, evaluate the coverage radius, and calculate the number of cells required to cover a given area. This paper takes into account the standard K factors model and then uses the Ion motion optimization (IMO) algorithm to set up a propagation model adapted to the physical environment of each of the Cameroonian cities of Yaoundé and Bertoua for different frequencies and technologies. Drive tests were made on the CDMA network in the city of Yaoundé on one hand and on an LTE TDD network in the city of Bertoua on the other hand. IMO is used as the optimization algorithm to deduct a propagation model which fits the environment of the two considered towns. The calculation of the root-mean-square error (RMSE) between the actual data from the drive tests and the prediction data from the implemented model allows the validation of the obtained results. A comparative study made between the RMSE value obtained by the new model and those obtained by the Okumura-Hata and K factors standard models, allowed us to conclude that the new model obtained in each of these two cities is better and more representative of our local environment than the Okumura-Hata currently implemented. The implementation shows that IMO can perform well and solve this kind of optimization problem;the newly obtained models can be used for radio planning in the cities of Yaounde and Bertoua in Cameroon.

关键词： Drive Test IMO Propagation Models Root Mean Square Error

Klingsor Syndrome: An Observation in a Patient with Schizophrenia

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Open Journal of Urology 2024年第5期14卷 346-351页

作者： Mbuya Musapudi eric Ouake Hadidjatou michel Agounkpe Yevi Dodji Magloire Inès Hodonou Fred Martin Avakoudjo Josué Georges Dejinnin Department of Urology and Andrology Hubert Koutoukou Maga National Teaching Hospital Cotonou Benin Department of Surgery University Clinics of Lubumbashi Lubumbashi Democratic Republic of the Congo

Background: Klingsor syndrome refers to genital self-mutilation in man following delusional religious beliefs. Later, Schweitzer proposed expanding the term to include all psychotic disorders, drug and alcohol abuse. Apart from the noted hemorrhagic emergency and difficult surgical operation, there is a psychosocial impact, sexual and urinary complications (stenosis, urethral fistula) which make this pathology complex. Aim: The Aim of this study is to describe the clinical case of Klingsor syndrome and evaluate its management in light of the literature. Case Presentation: We report a rare case of genital self-mutilation in a 35-year-old man, non-compliant schizophrenic, received 04 days after the trauma and whose treatment consisted of remodeling of the penis stump and follow-up by psychiatrists. Conclusion: Klingsor syndrome is a rare but serious phenomenon. Its management remains complex, but it must be early and multidisciplinary.

关键词： Klingsor Syndrome Génital Self-Mutilation Schizophrenia

COST 231-Hata Propagation Model Optimization in 1800 MHz Band Based on Magnetic Optimization Algorithm: Application to the City of Limbé

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Journal of Computer and Communications 2023年第2期11卷 57-74页

作者： eric.michel deussom djomadji Kabiena Ivan Basile Fobasso Segnou Thierry Tonye Emanuel Department of Electrical and Electronic Engineering College of Technology University of Buea Buea Cameroon Department of Electrical and Telecommunications Engineering National Advanced School of Engineering of Yaoundé University of Yaoundé I Yaoundé Cameroon Division of ICT National Advanced School of Post Telecommunication and ICT University of Yaoundé I Yaoundé Came-roon Department of Computer Engineering and Telecommunications National Advanced School of Engineering University of Douala Cameroon

Network planning is essential for the construction and the development of wireless networks. The network planning cannot be possible without an appropriate propagation model which in fact is its foundation. Initially used mainly for mobile radio networks, the optimization of propagation model is becoming essential for efficient deployment of the network in different types of environment, namely rural, suburban and urban especially with the emergence of concepts such as digital terrestrial television, smart cities, Internet of Things (IoT) with wide deployment for different use cases such as smart grid, smart metering of electricity, gas and water. In this paper we use an optimization algorithm that is inspired by the principles of magnetic field theory namely Magnetic Optimization Algorithm (MOA) to tune COST231-Hata propagation model. The dataset used is the result of drive tests carry out on field in the town of Limbe in Cameroon. We take into account the standard K-factor model and then use the MOA algorithm in order to set up a propagation model adapted to the physical environment of a town. The town of Limbe is used as an implementation case, but the proposed method can be used everywhere. The calculation of the root mean square error (RMSE) between the real data from the radio measurements and the prediction data obtained after the implementation of MOA allows the validation of the results. A comparative study between the value of the RMSE obtained by the new model and those obtained by the optimization using linear regression, by the standard COST231-Hata models, and the free space model is also done, this allows us to conclude that the new model obtained using MOA for the city of Limbe is better and more representative of this local environment than the standard COST231-Hata model. The new model obtained can be used for radio planning in the city of Limbé in Cameroon.

关键词： Radio Measurements Root Mean Square Error Magnetic Optimization Algorithm

Comparing Machine Learning Algorithms for Improving the Maintenance of LTE Networks Based on Alarms Analysis

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Journal of Computer and Communications 2022年第12期10卷 125-137页

作者： Batchakui Bernabe deussom djomadji eric.michel Chana Anne Marie Mama Tsimi Serge Fabrice Department of Computer Engineering National Advanced School of Engineering UY1 Yaoundé Cameroon Department of Electrical and Telecommunications Engineering National Advanced School of Engineering Yaoundé Cameroon College of Technology University of Buea Buea Cameroon

Mobile network operators are facing many challenges to satisfy their subscribers in terms of quality of service and quality of experience provided. To achieve this goal, technological progress and scientific advances offer good opportunities for efficiency in the management of faults occurring in a mobile network. Machine learning techniques allow systems to learn from past experiences and can predict, solutions to be applied to correct the root cause of a failure. This paper evaluates machine learning techniques and identifies the decision tree as a learning model that provides the most optimal error rate in predicting outages that may occur in a mobile network. Three machine learning techniques are presented in this study and compared with regard to accuracy. This study demonstrates that the appropriate machine learning technique improves the accuracy of the model. By using the decision tree as a machine learning model, it was possible to predict solutions to network failures, with an error rate less than 2%. In addition, the use of Machine Learning makes it possible to eliminate steps in the network failure processing chain;resulting in reduced service disruption time and improved the network availability which is a key network performance index.

关键词： 4G LTE Mobile Network Machine Learning Network Maintenance Troubleshooting Decision Tree Random Forest

Multivariate Approach to Characterizing Soil Quality of Gabonese’s Ferralitic Soils

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Open Journal of Soil Science 2024年第4期14卷 237-268页

作者： Neil-Yohan Musadji Rolf Gaël Mabicka Obame michel Mbina Mounguengui Jean Aubin Ondo Lydie-Stella Koutika eric Ravire Claude Geffroy Laboratoire De Chimie Des Milieux et Des Mat&#233riaux Inorganiques Laboratoire D&#8217Analyse Des Sols et Environnement D&#233partement Des Sciences Fondamentales De L&#8217Ing&#233nieur Institut National D&#8217Agronomie et De Biotechnologies Universit&#233 Des Sciences et Techniques De Masuku Franceville Gabon Institut De Chimie Des Milieux et Maté riaux De Poitiers (IC2MP) Universit&#233 De Poitiers Poitiers France Laboratoire De Chimie Des Milieux et Des Mat&#233riaux Inorganiques Laboratoire D&#8217Analyse Des Sols et Environnement D&#233partement De Phytotechnologie Institut National D&#8217Agronomie et De Biotechnologies Universit&#233 Des Sciences et Techniques De Masuku Franceville Gabon Dé partement De G&#233ologie Facult&#233 Des Sciences Universit&#233 Des Sciences et Techniques De Masuku Franceville Gabon Laboratoire Pluridisciplinaire Des Sciences Ecole Normale Sup&#233rieure Libreville Gabon Centre De Recherche Sur La Productivité et La Durabilit&#233 Des Plantations Industrielles Pointe Noire Republic of Congo Sucaf Gabon Somdiaa Franceville Gabon

Assessing soil quality is essential for crop management and soil temporal changes. The present study aims to evaluate soil quality in the Ferralitic soils context countrywide. This assessment was done using multivariate soil quality indice (SQI) models, such as additive quality index (AQI), weighted quality indexes (WQIadd and WQIcom) and Nemoro quality index (NQI), applied to two approaches of indicator selection: total data set (TDS) and minimum data set (MDS). Physical and chemical soil indicators were extracted from the ORSTOM’s reports resulting from a sampling campaign in different provinces of Gabon. The TDS approach shows soil quality status according to eleven soil indicators extracted from the analysis of 1,059 samples from arable soil layer (0 - 30 cm depth). The results indicated that 87% of all provinces presented a very low soil quality (Q5) whatever the model. Among soil indicators, exchangeable K+ and Mg2+, bulk density and C/N ratio were retained in MDS, using principal component analysis (PCA). In the MDS approach, 50 to 63% of provinces had low soil quality grades with AQI, WQIadd and NQI, whereas the total was observed with WQIcom. Only 25% of provinces had medium soil quality grades with AQI and NQI models, while 12.5% (NQI) and 25% (AQI) presented high quality grades. Robust statistical analyses confirmed the accuracy and validation (0.80 r P ≤ 0.016) of AQI, WQIadd and NQI into the TDS and MDS approaches. The same sensitivity index value (1.53) was obtained with AQI and WQIadd. However, WQIadd was chosen as the best SQI model, according to its high linear regression value (R2 = 0.82) between TDS and MDS. This study has important implications in decision-making on monitoring, evaluation and sustainable management of Gabonese soils in a pedoclimatic context unfavorable to plant growth.

关键词： Gabon Ferralitic Soil Soil Indicators Standard Score Function Soil Quality Indices Sustainable Soil Soil Management

Okumura Hata Propagation Model Optimization in 400 MHz Band Based on Differential Evolution Algorithm: Application to the City of Bertoua

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Journal of Computer and Communications 2023年第5期11卷 52-69页

作者： eric.michel deussom djomadji Ivan Basile Kabiena Joel Thibaut Mandengue Felix Watching Emmanuel Tonye Department of Electrical and Electronic Engineering College of Technology University of Buea Buea Cameroon Division of ICT National Advanced School of Post Telecommunication and ICT University of Yaounde I Yaounde Cameroon Department of Computer Engineering and Telecommunications National Advanced School of Engineering University of Douala Douala Cameroon Department of Electrical and Telecommunications Engineering National Advanced School of Engineering of Yaounde University of Yaounde I Yaounde Cameroon

Propagation models are the foundation for radio planning in mobile networks. They are widely used during feasibility studies and initial network deployment, or during network extensions, particularly in new cities. They can be used to calculate the power of the signal received by a mobile terminal, evaluate the coverage radius, and calculate the number of cells required to cover a given area. This paper takes into account the standard k factors model and then uses the differential evolution algorithm to set up a propagation model adapted to the physical environment of the Cameroonian cities of Bertoua. Drive tests were made on the LTE TDD network in the city of Bertoua. Differential evolution algorithm is used as the optimization algorithm to deduct a propagation model which fits the environment of the considered town. The calculation of the root mean square error between the actual data from the drive tests and the prediction data from the implemented model allows the validation of the obtained results. A comparative study made between the RMSE value obtained by the new model and those obtained by the Okumura Hata and free space models, allowed us to conclude that the new model obtained is better and more representative of our local environment than the Okumura Hata currently used. The implementation shows that Differential evolution can perform well and solve this kind of optimization problem;the newly obtained models can be used for radio planning in the city of Bertoua in Cameroon.

关键词： Radio Measurements Root Mean Square Error Differential Evolution Algorithm

Surgical Site Infections in Trauma and Orthopaedics at Bouaké Teaching Hospital (Côte d’Ivoire)

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Open Journal of Orthopedics 2024年第9期14卷 381-390页

作者： Loukou Blaise Yao Koffi Léopold Krah Aya Adelaïde Natacha Kouassi Kouamé Innocent M’bra Kouamé Jean-eric Kouassi michel Kodo Department of Trauma and Orthopaedics Bouak Teaching Hospital Bouak Cte dIvoire

Background: Surgical site infections are serious healthcare problems. The aim was to describe the epidemiological, diagnostic, therapeutic, and prognostic aspects of surgical site infections in Trauma and Orthopaedics at Bouaké Teaching Hospital. Method: This retrospective, descriptive, and analytical study was conducted from January 2019 to December 31, 2021. The data studied included prevalence, initial lesions, type of surgical intervention, type of SSI, bacteria involved, treatment, and outcomes. Results: Forty-four (11%) of the 399 patients included in the study developed a surgical site infection. The mean age was 27 years, with 36 male and 8 female. Initial lesions were predominantly open fractures (n = 31;70%), with a mean delay of 48 hours for surgical management. Emergency interventions accounted for 70% (n = 31) of cases. The NNISS infection risk score was 1 in 80% (n = 35) of cases. Superficial infections (n = 34;77%) appeared early, on a mean 6 days postoperatively. Bacteriological analysis primarily identified Pseudomonas aeruginosa (n = 10;23%), sensitive to Imipenem and Chloramphenicol but resistant to Amoxicillin-clavulanic acid, Ceftriaxone, Gentamicin, and Ciprofloxacin. Multidrug-resistant bacteria were found in 89% (n = 8) of cases, with all bacteria resistant to Ceftriaxone. Surgical revision was performed in 10 patients (23%), primarily involving debridement with hardware retention (n = 7;70%). Chloramphenicol was the most commonly used antibiotic post-antibiogram (61%). Outcomes were favourable in 98% of cases. Identified risk factors included the type of lesion according to NRC classification, the delay in managing open fractures, and the NNISS score. Conclusion: The prevalence of surgical site infection was 11%, favoured by the delayed operation of open fractures.

关键词： Surgical Site Infection Open Fractures Pseudomonas aeruginosa Ceftriaxone