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Estimatio. o. Finite Po.ulatio. To.als in High Dimensio.al Spaces

o.en Jo.rnal o. Statistics 2022年第5期12卷 581-596页

作者： Festus A. Were Geo.ge o. o.wa romanus o. otieno Department o. Statistics and Actuarial Sciences JKUAT Nairobi Kenya

In this paper, the pro.lem o. No.parametric Estimatio. o. Finite Po.ulatio. To.als in high dimensio.al datasets is co.sidered. A ro.ust estimato. o. the Finite Po.ulatio. To.al based o. Feedfo.ward Backpro.agatio. Neural Netwo.k is derived with the aid o. a Super-Po.ulatio. Mo.el. This current study is mo.ivated by the fact that Lo.al Po.yno.ials and Kernel metho.s have in preceding related studies, been sho.n to.pro.ide go.d estimato.s fo. Finite Po.ulatio. To.als but in lo. dimensio.s. Even in these situatio.s ho.ever, bias at bo.ndary po.nts presents a big challenge when using these estimato.s in estimating Finite Po.ulatio. parameters. The challenge wo.sens as the dimensio. o. regresso.s increase. This is because as the dimensio. o. the Regresso. Vecto.s gro.s, the Sparseness o. the Regresso.s’ values in the design space beco.es unfeasible, resulting in a decrease in the fastest achievable rates o. co.vergence o. the Regressio. Functio. Estimato.s to.ards the target curve, rendering Kernel Metho.s and Lo.al Po.yno.ials ineffective to.address these challenges. This study co.siders the technique o. Artificial Neural Netwo.ks which yields ro.ust estimato.s in high dimensio.s and reduces the estimatio. bias with marginal increase in variance. This is due to.its Multi-Layer Structure, which can appro.imate a wide range o. functio.s to.any required level o. precisio.. The estimato.’s pro.erties are develo.ed, and a co.pariso. with existing estimato.s was co.ducted to.evaluate the estimato.’s perfo.mance using real data sets acquired fro. the United Natio.s Develo.ment Pro.ramme 2020. The estimatio. appro.ch perfo.ms well in an example using data fro. a United Natio.s Develo.ment Pro.ramme 2020 o. the study o. Human Develo.ment Index against o.her facto.s. The theo.etical and practical results imply that the Neural Netwo.k estimato. is highly reco.mended fo. survey sampling estimatio. o. the finite po.ulatio. to.al.

关键词： Neural Netwo.ks Kernel Smo.ther Lo.al Po.yno.ial No.parametric

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Ro.ust Classificatio. thro.gh a No.parametric Kernel Discriminant Analysis

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o.en Jo.rnal o. Statistics 2022年第4期12卷 443-455页

作者： Macdo.ald G. o.udho.Geo.ge o. o.wa romanus o. otieno Festus A. Were Department o. Statistics and Actuarial Sciences Jomo Kenyatta University of Agriculture and Technology Nairobi Kenya

The pro.lem o. classificatio. in situatio.s where the assumptio. o. no.mality in the data is vio.ated, and there are no.-linear clustered structures in the dataset is addressed. A ro.ust no.parametric kernel discriminant classificatio. functio., which is able to.address this challenge, has been develo.ed and the misclassificatio. rates co.puted fo. vario.s bandwidth matrices. A co.pariso. with existing parametric classificatio. functio.s such as the linear discriminant and quadratic discriminant is co.ducted to.evaluate the perfo.mance o. this classificatio. functio. using simulated datasets. The results presented in this paper sho. go.d perfo.mance in terms o. misclassificatio. rates fo. the kernel discriminant classifier when the co.rect bandwidth is selected as co.pared to.o.her identified existing classifiers. In this regard, the study reco.mends the use o. the pro.o.ed kernel discriminant classificatio. rule when o.e wishes to.classify units into.o.e o. several catego.ies o. po.ulatio. gro.ps where parametric classifiers might no. be applicable.

关键词： Discriminant Analysis Kernel Discriminant No.parametric

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Classificatio. o. Stateless Peo.le thro.gh a Ro.ust No.parametric Kernel Discriminant Functio.

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o.en Jo.rnal o. Statistics 2022年第5期12卷 563-580页

作者： Macdo.ald G. o.udho.Geo.ge o. o.wa romanus o. otieno Festus A. Were Department o. Statistics and Actuarial Sciences Jomo Kenyatta University of Agriculture and Technology Nairobi Kenya

Statelessness is the absence o. any Natio.ality. These include the Pemba, Sho.a, Galjeel, peo.le o. Burundi and Rwanda descent, and children bo.n in Kenya to.British o.erseas Citizens after 1983. Frequently, they are no. o.ly undo.umented but also.o.ten o.erlo.ked and no. included in Natio.al Administrative Registers. Acco.dingly, find it hard to.participate in So.ial and Eco.o.ic Affairs. There has been a majo. push by UNHCR and internatio.al partners to.“map” the size o. stateless po.ulatio.s and their demo.raphic pro.ile, as well as causes, po.ential so.utio.s and human rights situatio.. o.e o. the requirements by the UNHCR in their push is fo. co.ntries to.find a po.ential so.utio. to.statelessness which starts with classifying/asso.iating a perso. fro. these co.munities to.a particular lo.al co.munity that is reco.nized in Kenya. This paper addresses this pro.lem by ado.ting a Ro.ust No.parametric Kernel Discriminant functio. to.co.rectly classify the stateless co.munities in Kenya and co.pare the perfo.mance o. this metho. with the existing techniques thro.gh their classificatio. rates. This is because No.-parametric functio.s have pro.en to.be mo.e ro.ust and useful especially when there exists auxiliary info.matio. which can be used to.increase precisio.. The findings fro. this paper indicate that No.parametric discriminant classifiers pro.ide a go.d classificatio. metho. fo. classifying the stateless co.munities in Kenya. This is because they exhibit lo.er classificatio. rates co.pared to.the parametric metho.s such as Linear and Quadratic discriminant functio.s. In additio., the finding sho.s that based o. certain similarities in characteristics that exist in these co.munities that surro.nd the Pemba Co.munity, the Pemba co.munity can be classified as Giriama o. Rabai in which they seem to.have a stro.g link. In this regard, the study reco.mends the use o. the Kernel discriminant classifiers in classifying the stateless perso.s and that the Go.ernment o. K

关键词： Discriminant Analysis Kernel Discriminant No.parametric Classificatio. Statelessness

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Preparatio. and Alkylatio. o. Carbo. Nano.ibers fro. Po.ymethyl Methacrylate

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Jo.rnal o. Materials Science and Chemical Engineering 2024年第9期12卷 55-68页

作者： Stephen Mukhebi Situma Geo.frey otieno Austin o. Aluo.h Dickso. M. Andala James o.o.r Scho.l o. Chemistry and Material Science Technical University of Kenya Haile Selassie Avenue Nairobi Kenya Chemistry Department Multi-Media University Nairobi Kenya

Carbo. nano.ibers have revo.utio.ized nano.echno.o.y due to.their po.ential applicatio.s in emerging fro.tiers o. research and industrial secto.s. This can be attributed to.their superio. pro.erties such as higher mechanical strength, unique surface characteristics, and impro.ed adherence that is transmitted into.the po.ymer matrix to.fo.m a nano.o.po.ite with impro.ed pro.erties. Po.ymethyl methacrylate is a co.mo. carbo. so.rce fo. the synthesis o. carbo. nano.ibres o. its high mechanical strength, thermal stability, and lo. mo.sture and water abso.bing capacity that allo.s its pro.ucts to.have several applicatio.s. In this wo.k, we repo.t the successful electro.pinning o. carbo. nano.ibres fro. Po.y methyl methacrylate and functio.alizing the resulting carbo. nano.ibres. The functio.alized carbo. nano.ibres were analyzed to.determine their so.ubility/dispersio. in selected o.ganic so.vents, then characterized using Fo.rier transfo.m infra-red spectro.co.y, Raman spectro.co.y, scanning electro. micro.co.y co.bined with Energy dispersive spectro.co.y and Thermalgravimetric analysis.

关键词： Po.ymethyl Methacrylate Electro.pinning Carbo. Nano.ibres Alkylatio.

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Wavelength Dependent No.linear Spectro.co.ic Study o. Third Harmo.ic Generatio. Pro.ed by Ro.atio.al Maker Fringes Metho.

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o.en Jo.rnal o. Micro.hysics 2024年第2期14卷 13-23页

作者： Calfo.d o.hiambo.otieno Department o. Physics Kisii University Kisii Kenya

Efficient third-o.der no.linearities o. the Zinc o.ide and Al-do.ed Zinc o.ide were studied by Third Harmo.ic Generatio. (Third Harmo.ic Generatio.) Maker fringes to.establish the effect Aluminum o. Aluminum do.ing (Al-do.ing) o. the cubic no.linearities. Adding the Al-do.ant to.the Zinc o.ide crystal structure results in changes that affect the o.tical and no.linear characteristics. Presented results indicate that the magnitude o. X(3) was enhanced at single experimental wavelengths;ho.ever, acro.s the bro.dband experimental spectrum, the effect o. Al-do.ing remained relatively co.stant. The o.served enhancement o. third-o.der no.linearity was purely fro. the bo.nd electro.ic respo.se. The o.servatio. is attributed to.increased charge carriers and spo.taneo.s po.arizatio. in the Zinc o.ide and Al-do.ed Zinc o.ide crystal structure.

关键词： No.linear o.tics Harmo.ic Generatio. Maker Fringes Zinc o.ide

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Density Functio.al Calculatio.s o. the Mechanical, Electro.ic and Dynamical Pro.erties o. Antipero.skite Ca₃Bo.(B = Pb, Ge, Sn)

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o.en Jo.rnal o. Micro.hysics 2024年第1期14卷 1-12页

作者： Phillip Wilfsen otieno Nyawere Department o. Physical and Bio.o.ical Sciences Kabarak University Nakuru Kenya

An analysis o. mechanical, electro.ic and dynamical pro.erties o. antipero.skite Ca3Bo.(B = Pb, Ge, Sn) in cubic phase space gro.p Pm-3m (221) has been studied using first principle density functio.al theo.y (DFT). Gro.nd state energy co.putatio. was do.e using the Pro.ecto. Augmented Wave (PAW) Pseudo.Po.entials and the Plane Wave (PW) basis set. The Generalized Gradient Appro.imatio. (GGA) was used fo. the exchange co.relatio.. The o.en so.rce co.e QUANTUM ESPRESSo.(QE) was used in this study in which plane wave basis sets are applied fo. the expansio. o. the electro.ic structure wave functio.. Thermo.pw as a po.t-pro.essing co.e was used fo. the co.putatio. o. mechanical pro.erties including bulk mo.ulus and elastic co.stants with their derivatives. The lattice parameters are here calculated to.be 4.87 Å, 4.86 Å and 4.84 Å fo. Ca3Bo.(B = Pb, Ge, Sn) respectively which co.pares well with o.her wo.ks. This also.sho.s that the three crystals are similar in size and in mo.t o. their pro.erties. In additio. to.this, pro.ected density o. states and band structure are also.co.puted bo.h sho.ing that these materials are o. semi-metallic nature and are stable in cubic phase. Pho.o. mo.es at gamma are also.repo.ted.

关键词： Antipero.skite Elastic Co.stants Generalized Gradient Appro.imatio.

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o.timizatio. o. Methylene Blue Dye Adso.ptio. o.to.Co.o.ut Husk Cellulo.e Using Respo.se Surface Metho.o.o.y: Adso.ptio. Kinetics, Iso.herms and Reusability Studies

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Jo.rnal o. Materials Science and Chemical Engineering 2024年第2期12卷 1-18页

作者： Frank o.ru o.wo.o.Geo.frey otieno Scho.l o. Chemistry and Material Science Technical University of Kenya Nairobi Kenya

In this study, co.o.ut husk cellulo.e was emplo.ed as a co.t-effective and enviro.mentally friendly adso.bent to.eliminate methylene blue (MB) dye fro. aqueo.s so.utio.s. The successful develo.ment o. respo.se surface metho.o.o.y paired with a central co.po.ite design (RSM-CCD) enabled the o.timizatio. and mo.elling o. the adso.ptio. pro.ess. The study investigated the individual and co.bined effects o. three variables (pH, co.tact time, and initial MB dye co.centratio.) o. the adso.ptio. o. MB dye o.to.co.o.ut husk cellulo.e. The develo.ed RSM-CCD mo.el exhibited a remarkable degree o. precisio. in predicting the remo.al efficiency o. MB dye within the specified experimental parameters. This was demo.strated by the stro.g regressio. parameters, with an R2 value o. 99.79% and an adjusted R2 value o. 99.6%. The study depicted that the o.timal parameters fo. attaining a 98.8827% remo.al o. MB dye using co.o.ut husk cellulo.e were as fo.lo.s: an initial MB dye co.centratio. o. 30 mg∙L−1, co.tact time o. 120 minutes, and pH 7 at a fixed adso.bent do.e o. 0.5 g. The Freundlich iso.herm mo.el pro.ided the mo.t satisfacto.y descriptio. o. the equilibrium adso.ptio. iso.herms, suggesting that MB dye adso.ptio. o.to.co.o.ut husk cellulo.e o.curs o. a hetero.eneo.s surface. The experimental results demo.strated a stro.g agreement with the pseudo.seco.d-o.der kinetics mo.el, indicating that the number o. active sites present o. the cellulo.e adso.bent predo.inantly influences the adso.ptio. pro.ess o. MB dye. Additio.ally, the adso.bent made fro. co.o.ut husk cellulo.e exhibited the po.ential to.be reused, as it retained its efficiency fo. a maximum o. three cycles o. adso.ptio. o. MB dye. The results o. this study sho. that co.o.ut husk cellulo.e has the po.ential to.be an effective and sustainable adso.bent fo. remo.ing MB dye fro. aqueo.s so.utio.s.

关键词： Adso.ptio. Kinetics Iso.herms o.timizatio. Respo.se Surface Metho.o.o.y Cellulo.e

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Assessment o. Gro.ndwater Stability Using Co.ro.io. and Scaling Tendency Indices o. Selected Springs in the Manga Regio. in Nyamira Co.nty, Kenya

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o.en Jo.rnal o. Micro.hysics 2024年第3期14卷 79-88页

作者： Calfo.d o.hiambo.otieno Alice Mako.jo.Wekesa Physics Department Kisii University Kisii Kenya

We present the result o. gro.ndwater stability assessment o. three majo. springs in the Manga regio. in Nyamira Co.nty fo.nd in Kenya in 2018. These springs are Kiango.o.(SP1), Kero.go.(SP2) and Tetema (SP3). The co.ro.io. and scaling tendency indices were o.tained using the Langelier saturatio. index (LSI), Ryznar stability index (RSI), and Pucko.ius scaling index (PSI). The LSI values o.tained fo. SP1, SP2, and SP3 are −3.93, −4.71, and −4.17, respectively, while using RSI, the values o.tained fo. SP1, SP2, and SP3 are 14.15, 14.53, and 13.74, respectively. Using PSI, the values o. SP1, SP2, and SP3 are 5.58, 5.45, and 5.58, respectively. Fro. the interpretatio. o. the indices, the gro.ndwater fro. the three springs in the Manga regio. using LSI and RSI sho.ed into.erable co.ro.io.;hence, it is unlikely to.scale as o.tained fro. PSI.

关键词： Langelier Saturatio. Index Ryznar Stability Index Pucko.ius Scaling Index

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Effects o. Papyrus Plants (Cyperus papyrus) o. the Physico.hemical Parameters and Nutrient Levels o. Water and Sediments in Yala Swamp Wetland in Western Kenya

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Jo.rnal o. Bio.hysical Chemistry 2024年第1期15卷 1-23页

作者： Vio.et Achieng o.o.o.Paul otieno Abuo. Emmanuel Amuko.e Shikanga Elly Tetty o.ewe Do.glas Nyambane Anyo.a Fredrick Mhina Mngube Stephen Ado.go.o.o.go Department o. Enviro.mental Studies Maseno University Kisumu Kenya Department o. Chemistry Maseno University Kisumu Kenya Department o. Physical and Bio.o.ical Sciences Murang’a University of Technology Murang’a Kenya Wetlands Internatio.al Dar es Salaam Tanzania Department o. Physical Sciences Jaramogi Oginga Odinga University of Science and Technology Bondo Kenya

Yala swamp wetland is the largest fresh water wetland eco.ystem in Kenya suppo.ting a bro.d bio.iversity. It co.prises o. River Yala, the Yala swamp, Lakes Kanyabo.i, Nambo.o.and Sare, and a po.tio. o. Lake Victo.ia neighbo.ing the swamp. Appro.imately 2300 ha o. land have been reclaimed and has been used fo. large-scale agriculture resulting in mass destructio. o. papyrus to.create ro.m fo. framing. Papyrus are kno.n to.be impo.tant in phyto.emediatio. but despite this ro.e info.matio. is limited, lacks suppo.tive evidence and the empirical aspect o. the levels o. these po.lutants in relatio. to.the papyrus bio.ass is limited. The study is aimed at determining the effects o. Cyperus papyrus o. the water and sediment quality in Yala Swamp wetland. Six sampling sites were purpo.efully selected to.mo.ito. the variatio.s o. the physico.hemical parameters (temperature, disso.ved o.ygen: Do. pH, bio.o.ical o.ygen demand: Bo., to.al suspended so.ids: TSS, turbidity, electrical co.ductivity: EC and to.al disso.ved so.ids: TSS) and the levels selected nutrients (pho.pho.us and nitrates) in water and sediments as River Yala flo.s thro.gh Do.inio. Farms, Lake Sare which surro.nded by Cyperus papyrus and finally into.Lake Victo.ia. The samples were co.lected in triplicates during the wet and dry seaso.s (May and September 2015 respectively). The physico.hemical parameters were measured in situ using a Hydro.ab muiltimeter while the nutrients were analyzed using UV/Vis spectro.co.y. Statistical analysis was do.e using SAS V9.0 so.tware. The mean temperature was 26.19˚C ± 0.71˚C, Do. 3.72 ± 1.02 Mg/l, Bo.: 3.9 ± 0.32 Mg/l, pH: 7.52 ± 0.17, TDS: 109 ± 86.33, EC: 173.26 ± 13.8 μS/cm, TSS: 12.42 ± 18.51 Mg/l and Turbidity: 12.29 ± 10.03 NTU. The values varied significantly at P 0.05 amo.g all the sites. The results sho. that papyrus is useful in maintaining the required levels o. physico.hemical parameters. The study will assist in co.servatio. o. the papyrus to.help phyto.emediate

关键词： Adso.bing Co.taminants Phyto.emediatio. Co.servatio. Cyperus papyrus

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Estimatio. o. Po.ulatio. Variance Using the Co.fficient o. Kurto.is and Median o. an Auxiliary Variable under Simple Rando. Sampling

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o.en Jo.rnal o. Statistics 2017年第6期7卷 944-955页

作者： To.ui Kiplangat Milto. romanus otieno o.hiambo.Geo.ge otieno o.wa Pan African University Institute for Basic Sciences Technology and Innovation (PAUISTI) Nairobi Kenya Department o. Statistics and Actuarial Science Jomo Kenyatta University of Agriculture and Technology Nairobi Kenya

In this study we have pro.o.ed a mo.ified ratio.type estimato. fo. po.ulatio. variance o. the study variable y under simple rando. sampling witho.t replacement making use o. co.fficient o. kurto.is and median o. an auxiliary variable x. The estimato.’s pro.erties have been derived up to.first o.der o. Taylo.’s series expansio.. The efficiency co.ditio.s derived theo.etically under which the pro.o.ed estimato. perfo.ms better than existing estimato.s. Empirical studies have been do.e using real po.ulatio.s to.demo.strate the perfo.mance o. the develo.ed estimato. in co.pariso. with the existing estimato.s. The pro.o.ed estimato. as illustrated by the empirical studies perfo.ms better than the existing estimato.s under so.e specified co.ditio.s i.e. it has the smallest Mean Squared Erro. and the highest Percentage Relative Efficiency. The develo.ed estimato. therefo.e is suitable to.be applied to.situatio.s in which the variable o. interest has a po.itive co.relatio. with the auxiliary variable.

关键词： Mo.ified Ratio Type Variance Estimato. Study Variable Auxiliary Variable Kurto.is Median Bias Mean Squared Erro. (MSE) Percentage Relative Efficiency (PRE) Simple Rando. Sampling

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