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Maintenance Strategies and Spare Parts Inventory Management for Use of Reconditioned Items

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Engineering（科研） 2022年第8期14卷 360-370页

作者： Mamadou Sagne mouhamed fadel Niang Doctoral School for Sustainable Development and Society Iba Der Thiam University Thies Senegal

The maintenance management of construction equipment occupies a prominent place in the overall strategy for managing the equipment fleet. It is also linked to the management of the stock of spare parts and particularly reconditioned spare parts. Because of the relatively low purchase cost of these, most companies are tempted by this option. The purpose of this article is precisely to study the impact of this category of parts in the stock and also in the optimization of maintenance costs, knowing that to do this;their use must obey certain constraints. It is therefore important to be able to characterize these reconditioned parts by estimating their optimal age, and studying their advantages and also their limits. The determination of the optimal age of reconditioned parts will be such that the total cost of replacement with used parts is at most equal to the total cost of replacement with new parts at the end of the operating period.

关键词： Strategies Maintenance Spare Parts Reconditioned

Modeling and Simulation of CDMA Codes in Scilab

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International Journal of Communications, Network and System Sciences 2015年第7期8卷 274-281页

作者： mouhamed fadel diagana Serigne Bira Gueye Department of Physics Faculty of Sciences and Techniques Cheikh Anta Diop University Dakar-Fann Senegal

Prior to hardware implementation, simulation is an important step in the study of systems such as Direct Sequence Code Division Multiple Access (DS-CDMA). A useful technique is presented, allowing to model and simulate Linear Feedback Shift Register (LFSR) for CDMA. It uses the Scilab package and its modeling tool for dynamical systems Xcos. PN-Generators are designed for the quadrature-phase modulation and the Gold Code Generator for Global Positioning System (GPS). This study gives a great flexibility in the conception of LFSR and the analysis of Maximum Length Sequences (MLS) used by spread spectrum systems. Interesting results have been obtained, which allow the verification of generated sequences and their exploitation by signal processing tools.

关键词： Code Division Multiple Access (CDMA) Linear Feedback Shift Register (LFSR) Maximum Length Sequence (MLS) Spread-Spectrum Scilab Xcos Direct Sequence Spread Spectrum (DSSS)

Analysis, Design, and Test of CDMA LFSR with Offset Mask Using Standard ICs

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Engineering（科研） 2016年第4期8卷 226-231页

作者： mouhamed fadel diagana Serigne Bira Gueye Engineering Institute of Computer Science and Telecommunications (I3T) Dakar Senegal Department of Physics Faculty of Sciences and Techniques Cheikh Anta Diop University Dakar Senegal

Hardware implementation of Linear Feedback Shift Register (LFSR) plays a great and very important role in communication systems, and in many security devices. In this paper, a design of LFSR with offset mask has been presented, for Direct Sequence Code Division Multiple Access (DS-CDMA) applications. Integrated electronic components have been used. An accessible model facilitating the synthesis on Printed Circuit Boards (PCB) and implementation on Field Programmable Gate Array (FPGA) is offered. In addition, a temporal and spectral analysis of the circuit is performed in order to validate the design. This latter facilitates the generation of pseudo-random codes based on LFSR and their integration into electronic systems.

关键词： LFSR CDMA DS-CDMA PCB FPGA Integrated Circuit (IC) Spread Spectrum (SS) Modular Shift Register (MSRG)

Modeling the Hydrological Dynamic of the Breeding Water Bodies in Barkedji’s Zone

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Journal of Water Resource and Protection 2014年第8期6卷 741-755页

作者： Mamadou Bop Angelina Amadou Ousmane Seidou Cheikh mouhamed fadel Kébé Jacques André Ndione Soussou Sambou Ibrah Seidou Sanda Agrhymet Regional Center Niamey Niger Centre de Suivi écologique (CSE) Dakar Sénégal Centre International de Formation et de Recherche en Energie Solaire (CIFRES) Département de Génie Civil Ecole Supérieure Polytechnique Université Cheikh Anta Diop Dakar Sénégal Department of Civil Engineering University of Ottawa Ottawa Canada Laboratoire d’Hydraulique et de Mécanique des Fluides Département de Physique Faculté des Sciences et Techniques Université Cheikh Anta Diop de Dakar Dakar Sénégal

Temporary water bodies’ dynamics play an important role in the epidemiological chain-borne diseases such as Rift Valley fever as they are the main breeding habitats for mosquitoes. During the rainy season, hundreds of these temporary water bodies appear and grow in the Ferlo region (Senegal). The purpose of this research is to generate historical and future time series water levels and areas at three temporary ponds located in the environment and health observatory of Barkedji. A simple lumped hydrological model was developed for that purpose. It describes each pond watershed as three interconnected reservoirs: canopy, surface storage and soil storage and uses a linear relation to describe infiltration, percolation and baseflow (out of the soil reservoir). Given the depth of the water table in the region, percolation out of the soil surface is considered lost. Evapotraspiration was calculated using the Penman equation and withdraws water from the canopy and surface water reservoirs. Excess runoff from the soil storage is turned into runoff using a triangular unit hydrograph. The calibration was done using two years of hydrological and climatic data collected during the 2011 and 2012 rainy seasons. The calibration was successful and water level in the two ponds was simulated with a Root Mean Square Error (RMSE) of 11.2 to 15 cm. Because of the short duration of the observation, no validation could be done. Given the excellent agreement of the simulated and observed water levels during the calibration phase, the modeling exercise was considered to be successful. The developed models were used to generate historical time series of pond areas and correlate these to mosquitoes’ infestation in the region. Future time series of pond areas were also generated using downscaled outputs of three regional climate models from the AMMA ENSEMBLES experiment. The generated pond levels and areas are being used to assess the evolution of the disease in the next 40 years.

关键词： Breeding Areas Hydrology Pond Dynamics Climate Change

Upper arm length along with mid-upper arm circumference to enhance wasting prevalence estimation and diagnosis:sensitivity and specificity in 6-59-months old children

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Family Medicine and Community Health 2021年第2期9卷 24-30页

作者： mouhamed Barro Mohamed Daouda Baro Djibril Cisse Noel Zagre Thierno Ba Shanti Neff Baro Yacouba diagana Nutrition and development association NouakchottMauritania Nutrition UNICEFNouakchottMauritania UNICEF West and Central Africa Regional Office DakarSenegal Ministry of Health NouakchottMauritania Independent Consultant in Biostatistics ParisFrance University of Nouakchott NouakchottMauritania

Objective To evaluate the added value of the use of upper arm length(UAL)along with mid-upper arm circumference(MUAC)to diagnose and estimate the prevalence of wasting in comparison to current WHO standard and other MUAC-based *** UAL and usual anthropometric measurements were collected during a national cross-sectional nutritional *** were classified into three upper arm length groups(UALGs):UALG1,UALG2 and UALG3 according to the following UAL limits:≤150,151-180 and≥181 mm,*** operating characteristic curves were used to determine the best MUAC cut-off for each group using weight-for height Z-score(WHZ)as a reference *** prevalence,sensitivity and specificity of all diagnostic methods were *** This study was conducted in *** National representative sample of children from 6 to 59 months *** In total,12590 children were included in the *** prevalence was 16.1%,5.0%and 12.5%when diagnosed by WHZ<−2,MUAC<125 mm and MUAC-UALG methods,*** the MUAC-UALG method increased the sensitivity for wasting diagnosis from 17.98%with MUAC<125 mm to 39.43%with *** specificity decreased from 97.49%with MUAC<125 mm to 92.71%with *** MUAC-height Z score and MUAC<138 mm,sensitivity was 26.04%and 69.76%and specificity were 97.40%and 75.64%*** This alternative method using MUAC tape to measure UAL increases the wasting diagnosis accuracy and allows for a better estimation of wasting *** method could be used as a potential alternative method for quick surveys in emergency settings such as Corona virus disease 2019 context.

关键词： diagnosis estimation Upper