Hasil Pencarian  ::  Simpan CSV :: Kembali

"Tesis ini berisi sebuah studi mengenai pemodelan matematis sebuah sistem sel tunam membran pertukaran proton tipe kanal paralel dan serpentine 1 dimensi dan 2 dimensi kondisi tunak (steady state) dan isotermal . Pemodelan mencakup perhitungan numerik persamaan konservasi massa dan momentum melalui teknik volume hingga (finite volume) tools komersial. Diskretisasi model dilakukan pada sub sistem kanal aliran (channel flow) dan lapisan membran MEA (membrane electrolyte assembly). Untuk mengetahui karakteristik utama gas reaktan di dalam kanal dalam hubungannya terhadap densitas arus. Dari hasil distribusi momentum dan massa yang diperoleh, selanjutnya menggunakan hubungan arus dan konsentrasi reaktan didapatkan bahwa kanal distribusi tipe serpentine mempunyai rugi aliran yang lebih besar daripada kanal paralel. Semakin besar tekanan statik rata-rata yang terjadi maka akan meningkatkan konsentrasi distribusi gas reaktan pada permukaan difusi.

---

This study explaining the development of Mathematical Modeling for Paralel and Serpentine channel distribution in Proton Exchange Membrane Fuel Cell (PEMFC). The models defined on the steady, isothermal, 1 and 2 dimensional, applying the governing equations of momentum and mass transfer to obtain the dynamic and mass parameter of reactants distribution. Model discretization carried on the sub systems of channel flow and Membrane Electrolyte Assembly (MEA) layer to know the main characteristic of reactant gas in the channel related to the current density. Finally using the relationship between concentration and current, from the result of momentum and mass distribution has been obtained that the serpentine channel shows the more higher pressure drop than the paralel one. Generally the higher pressure the more heavier concentration taken place on the diffusion layers."

"This book introduces a series of problems and methods insufficiently discussed in the field of Fractional Calculus – a major, emerging tool relevant to all areas of scientific inquiry. The authors present examples based on symbolic computation, written in Maple and Mathematica, and address both mathematical and computational areas in the context of mathematical modeling and the generalization of classical integer-order methods. Distinct from most books, the present volume fills the gap between mathematics and computer fields, and the transition from integer- to fractional-order methods."

"Danau Kenanga Universitas Indonesia mengalami penambahan nutrien berupa nitrogen yang berasal dari kegiatan domestik dan komersil di sekitar kampus. Pembebanan nitrogen yang berlangsung secara terus menerus telah meningkatkan produktivitas produsen primer di danau, sehingga kualitas air danau menurun dan menyebabkan terjadinya eutrofikasi. Danau Kenanga berpotensi untuk dijadikan sumber air baku di Kampus UI sehingga pemantauan kualitas air danau ditinjau dari konsentrasi nitrogen perlu dilakukan agar dapat dilakukan manajemen danau yang tepat. Pemantauan konsentrasi senyawa nitrogen dapat dilakukan melalui pemodelan yang memetakan perubahan konsentrasi total nitrogen terhadap waktu. Pemodelan konsentrasi total nitrogen di Danau Kenanga menggunakan metode numerik Runge-Kutta orde ke-4 dengan selang waktu 24 jam dan mempertimbangkan proses adveksi-difusi. Konsentrasi total nitrogen diukur pada inlet Danau Kenanga serta keempat titik yang mewakili sistem danau, kemudian dilakukan pemodelan yang menggambarkan konsentrasi total nitrogen selama 7 hari. Beban pencemar yang masuk ke Danau Kenanga diperoleh dengan mengalikan debit saluran dan konsentrasi di inlet danau. Penelitian ini merupakan pengembangan dari model yang dihasilkan oleh Kurnianto (2017) menggunakan objek penelitian Danau Kenanga UI. Penelitian ini bertujuan untuk: (1) Menganalisis pembebanan nitrogen pada danau dalam bentuk perhitungan imbangan nitrogen, (2) memodelkan konsentrasi total nitrogen dengan memperhitungkan mekanisme transport berupa difusi, serta menganalisis pengaruh mekanisme difusi dan adveksi terhadap akurasi hasil pemodelan, (3) Menganalisis pengaruh penambahan persamaan difusi terhadap hasil simulasi, dan (4) Memperkirakan pembebanan ideal pada danau agar memenuhi baku mutu kelas 1 menurut Peraturan Pemerintah No. 82 Tahun 2001. Pemodelan akan membandingkan simulasi adveksi dan adveksi-difusi. Akurasi pemodelan diukur menggunakan standard error of the estimate, dan hasil perhitungan adveksi dan adveksi-difusi menghasilkan standard error masing-masing sebesar 30,597% dan 30,569%. Hasil ini menunjukkan bahwa mekanisme transpor di danau terjadi dalam intensitas yang rendah sehingga tidak meningkatkan akurasi pemodelan secara signifikan. Hasil lain dari studi ini memperlihatkan bahwa berdasarkan perhitungan beban pencemaran dalam kondisi steady-state, konsentrasi total nitrogen di inlet Danau Kenanga harus dikurangi sebesar 90,15% agar danau dapat dijadikan sumber air baku."

"Penyakit Tuberkulosis di Indonesia merupakan salah satu dari 10 besar penyebab kematian dan agen infeksi utama. Penyebaran penyakit TB dapat dicegah dengan memberikan tes TB dini untuk individu dengan indikasi penyakit TB, seperti individu dari negara dengan kasus TB tinggi, orang yang tinggal atau bekerja di lingkungan berisiko tinggi, petugas kesehatan yang merawat pasien dengan risiko tinggi. Penyakit TBC dapat diketahui dengan TB Skin Test (TST) dan TB Blood Test. Kegagalan pengobatan terjadi ketika seorang individu gagal untuk pulih dari pengobatan lini pertama yang diberikan kepada individu TB aktif. Pada skripsi ini disusun model matematika dengan membagi total populasi  menjadi enam kompartemen berdasarkan status kesehatannya. Digunakan data pertambahan kasus TB Indonesia per-triwulan tahun 2017-2021 serta beberapa metode seperti pembentukan Basic Reproduction Number (R0) menggunakan metode NGM, menentukan dan analisis titik bebas penyakit dan endemik dengan pendekatan Van den Driessche, Castillo-Chavez dan Song, serta kajian analitik dengan analisis elastisitas dan sensitivitas serta simulasi autonomous.

---

Tuberculosis in Indonesia is one of the top 10 causes of death and a major infectious agent. The spread of TB disease can be prevented by providing early TB testing for individuals with indications of TB disease, such as individuals from countries with high TB cases, people living or working in high-risk environments, health workers who care for high-risk patients. TB disease can be identified by means of the TB Skin Test (TST) and the TB Blood Test. Treatment failure occurs when an individual fails to recover from the first-line treatment given to an individual with active TB. In this thesis is constructed a mathematical model by dividing the total population into six compartments based on their health status. The use of data on the increase in Indonesia TB cases per quartely 2017-2021 as well as several methods such as the formation of R0 or Basic Reproduction Number using the NGM or Next Generation Matrix method, determine and analyze disease and endemic points with the Van den Driessche approach, Castillo-Chavez and Song, as well as analytical studies with elasticity and sensitivity analysis as well as autonomous simulation."

"This book describes the modelling and optimisation of vibration reduction systems in an integrated fashion using nonlinear equations of motion. It proposes an effective optimisation method for determining the basic characteristics of the non-linear visco-elastic elements used in passive vibration reduction systems. In the case of semi-active and active vibration isolators, a design process of the advanced control systems is proposed that makes possible to optimise the controller settings relatively to the selected vibro-isolation criteria. The approach developed here is subsequently tested by means of experimental investigations conducted on various sample vibration reduction systems: passive, semi-active and active."

"The multiple signal demixing and parameter estimation problems that result from the impacts of background noise and interference are issues that are frequently encountered in the fields of radar, sonar, communications, and navigation. Research in the signal processing and control fields has always focused on improving the estimation performance of parameter estimation methods at low SNR and maintaining the robustness of estimations in the presence of model errors. This book presents a universal and robust relaxation estimation method (RELAX), and introduces its basic principles and applications in the fields of classical line spectrum estimation, time of delay estimation, DOA estimation, and radar target imaging. This information is explained comprehensively and in great detail, and uses metaphors pertaining to romantic relationships to visualize the basic problems of parameter estimation, the basic principles of the five types of classical parameter estimation methods, and the relationships between these principles. The book serves as a reference for scientists and technologists in the fields of signal processing and control, while also providing relevant information for graduate students in the related fields."

"Pada skripsi ini dibahas model matematika yang menggambarkan transmisi kebiasaanmerokok di antara populasi dengan mempertimbangkan efek dari kampanye media.Model ini mempertimbangkan efek kampanye media untuk merangsang seseorang menjadinon-perokok, baik sementara atau permanen. Model dibentuk dengan pendekatansistem persamaaan diferensial biasa non-linier berdimensi lima. Model yang dibangunkemudian dianalisis secara analitik dan numerik. Kajian analitik yang dilakukanadalah proses nondimensionalisasi, analisis eksistensi dan kestabilan titik keseimbangan,menghitung nilai basic reproduction number (R0), dan analisis bifurkasi. Dihasilkanbahwa titik keseimbangan bebas rokok (SFE) stabil secara lokal ketika (R0 < 1), sementaraitu selalu ada titik keseimbangan endemik ketika (R0 > 1). Model ini juga menunjukkanadanya bifurkasi mundur pada saat R0 = 1. Kemudian, dilakukan kajian numerikuntuk mendukung hasil dari kajian analitik sebelumnya berupa analisis sensitivitas danelastisitas R0 dan simulasi autonomous. Beberapa simulasi numerik juga diberikan untukmendukung hasil dari kajian analitik

---

In this thesis discussed a mathematical model which describe the transmission of smoking

habit among population considering the effect of the media campaign. This model

was taking into account the effect of the media campaign to stimulate an individual to be

a non-smoker, whether it’s temporary or permanent. The model is formed by the fivedimensional

nonlinear ordinary differential equation approach. The constructed model is

then analyzed analytically and numerically. The analytical study is a nondimensionalization

process, an analysis of the existence and stability of the equilibria, calculating the

value of textitbasic reproduction number (R0) and the bifurcation analysis. Generated

that smoking-free equilibrium(SFE) is locally stable when the basic reproduction number

(R0 < 1), while it always exists an endemic equilibrium point when R0 > 1. This

model also indicates the presence of backward bifurcation at R0 = 1. Sensitivity analysis

on R0 indicates the potential of a media campaign to help the government to reduce the

spread of smoking among the population. Some numerical simulations for supporting the

analytical is also given."

"Dalam peningkatan kualitas perairan seperti danau, diperlukan pengamatan dan analisis mengenai polutan yang mencemari perairan. Pada penelitian ini dibahas konstruksi model matematika Streeter−Phelps yang menggambarkan proses pemurnian pada danau yang terjadi secara mandiri atau disebut self purification. Model tersebut merepresentasikan konsentrasi oksigen dalam danau dan konsentrasi biochemical oxygen demand (BOD), yang didefinisikan sebagai jumlah oksigen maksimum yang dapat dikonsumsi polutanper satuan volume. Sebelum dilakukan konstruksi model Streeter−Phelps dilakukan pemodelan matematika pemurnian danau untuk kasus yang sederhana, yaitu danau dengan konsentrasi polutan homogen, konsentrasi polutan nonhomogen, dan pemurnian danau yang terjadi secara difusi. Konstruksi model dilakukan menggunakan persamaan diferensial biasa, persamaan diferensial parsial, dan sistem dinamik. Model Streeter−Phelps yang telah didapat dibagi menjadi dua kasus untuk danau yang tercemar ringan dan tercemar berat. Interpretasi model diberikan melalui solusi analitik, grafik solusi, dan bidang fase antara konsentrasi oksigen dan konsentrasi BOD.

---

In order to improve water quality in lakes, it is necessary to observe and analyze the pollutant that contaminate the water. This research discusses the construction of the Streeter−Phelps mathematical model which describes the purification process in the lake that occurs naturally in the lake itself or is called self purification. This model describes the oxygen concentration in the lake and the concentration of biochemical oxygen demand (BOD), defined as the maximum amount of oxygen that pollutants can consume per unit volume. Before constructing the Streeter−Phelps model, mathematical modeling of lake purification is carried out for several simple cases, namely lakes with homogeneous pollutant concentrations, nonhomogeneous pollutant concentrations, and lake purification that occurs by diffusion. The model construction is carried out using ordinary differential equations, partial differential equations, and dynamical systems. The Streeter−Phelps model is divided into two cases which are lightly polluted and heavily polluted lakes. The interpretation of the model is given by an analytical solution, the graph of the solution, and the phase plane depicting the relationship between oxygen concentration and BOD concentration."

"This book presents methods of mathematical modeling from two points of view. Splines provide a general approach while compartment models serve as examples for context related to modeling. The preconditions and characteristics of the developed mathematical models as well as the conditions surrounding data collection and model fit are taken into account. The substantial statements of this book are mathematically proven. The results are ready for application with examples and related program codes given.In this book, splines are algebraically developed such that the reader or user can easily understand and vary the numerical construction of the different kinds of spline functions. The classical compartment models of the pharmacokinetics are systematically analyzed and connected with lifetime distributions. As such, parameter estimation and model fit can be treated statistically with a varied minimum chi-square method. This method is applicable for single kinetics and also allows the calculation of average kinetics.--"