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All Journal EKSAKTA: Journal of Sciences and Data Analysis MATEMATIKA SAINS DAN MATEMATIKA Journal of Mathematical and Fundamental Sciences Jurnal Matematika: MANTIK Communication in Biomathematical Sciences International Journal of Computing Science and Applied Mathematics
sutimin sutimin
Department Of Mathematics, Diponegoro University, Jl. Prof. H. Soedarto SH, Tembalang, Semarang 50275
Astronomy Chemical Engineering, Chemistry & Bioengineering Chemistry Computer Science & IT Earth & Planetary Sciences Education Materials Science & Nanotechnology Mathematics Physics Social Sciences

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Journal : MATEMATIKA

 1 
ANALISIS BIFURKASI MODEL PERTUMBUHAN TUMOR DENGAN PERSAMAAN LOGISTIK WAKTU TUNDA Dewi, Febriana; sutimin, sutimin
MATEMATIKA Vol 14, No 1 (2011): JURNAL MATEMATIKA
Publisher : MATEMATIKA

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Abstract

In this paper is being studied about the logistic tumor growth model with time delay. The mathematical model is in non-linear differential equation with time delay difficult to find the solution analytically, so here we analyze the behavior of the model through perturbation. The tumor growth model has two equilibriums (i.e.at and ). Because this growth model is non-linear hence to analyze the stability of each equilibrium point is done through the linearization method. By using a perturbation procedure, the equilibrium point is unstable and is stable. The equilibrium is stable for , unstable for  and Hopf bifurcation occurs at .
MODEL PERTUMBUHAN BIOMASSA RUMPUT LAUT GRACILLARIA DENGAN CARRYING CAPACITY BERGANTUNG WAKTU Zullaikah, Zullaikah; sutimin, sutimin
MATEMATIKA Vol 11, No 2 (2008): Jurnal Matematika
Publisher : MATEMATIKA

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Abstract

In this journal, we will discuss concerning with a dynamical model of growth of seaweed biomass. The model will be applied in the biomass growth of Gracillaria  seaweed. The dynamical model is developed from the simple logistic model by considering the influence of resource absorption of ecosystem which support the environment. We assume that the resource absorption changes time dependent. By this assume, we include that the carrying capacity as function of time. To analyze the stability of the model equation, here we use the linearization method of the expansion series  
MODEL DINAMIK PERTUMBUHAN BIOMASSA UDANG WINDU DENGAN FAKTOR MORTALITAS BERGANTUNG WAKTU sulanjari, Sulanjari; sutimin, sutimin
MATEMATIKA Vol 11, No 3 (2008): JURNAL MATEMATIKA
Publisher : MATEMATIKA

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Abstract

In this paper will be discussed the growth model of shrimp biomass. Biomass is total weight from population. The growth model of shrimp biomass is influenced by the growth model of weight and of population. The growth model of weight, here will be governed and based on Von Bertalanffy’s model. The growth model of number population based on the exponential model and it has been constructed by mortality formula. From the growth model of shrimp biomass will be predicted when accurate harvest time to know the optimal harvest product.  
KLASIFIKASI INTERAKSI GELOMBANG PERMUKAAN BERTIPE DUA SOLITON sutimin, Sutimin; Rusgiyono, Agus
MATEMATIKA Vol 4, No 1 (2001): JURNAL MATEMATIKA
Publisher : MATEMATIKA

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Abstract

Pada tulisan ini diselidiki, masalah klasifikasi interaksi gelombang bertipe dua soliton Kadomtsev-Petviashvilli (KP). Disini dianalisis berdasarkan parameter interaksi dua solusi soliton baik melalui harga eksak maupun proses pelimitan. Proses pelimitan ini dilakukan untuk mengetahui resonansi diantara dua soliton. Selanjutnya  resonansi soliton ini dikaji untuk mendapatkan soliton yang baru.
ANALISIS KESTABILAN MODEL DINAMIK NITROGEN DAN HUBUNGANNYA DENGAN PERTUMBUHAN LOGISTIK ALGA widowati, widowati; sutimin, sutimin; ps, hermin; is, Tarita
MATEMATIKA Vol 12, No 3 (2009): JURNAL MATEMATIKA
Publisher : MATEMATIKA

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Abstract

The nitrogen dynamics model  related to algae growth is proposed. The form of the model is nonlinear differential equation system. From these model, the stability of the equilibrium point is disscussed. The stability is analized through the eigen values of the Jacobian matrix that is obtained from linearized system.  From the simulation results is found that ammonia-nitrogen, nitrite-nitrogen, and nitrate-nitrogen concentration will achieve to a certain value. The changed of ammonia-nitrogen, nitrite-nitrogen,  and nitrate-nitrogen concentration are effected by the algae density. If the alga density increase then the ammonia-nitrogen and nitrite-nitrogen concentrations will increase but the nitrate concentration will decrease.  
DEFORMASI INTERAKSI DUA PAKET GELOMBANG DARI PERSAMAAN IMPROVED KdV (IKdV Sutimin, Sutimin
MATEMATIKA Vol 9, No 1 (2006): JURNAL MATEMATIKA
Publisher : MATEMATIKA

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Abstract

Here, We will study the nonlinear two waves packet interaction. The two waves packet is modeled by Improved Koreteweg de-Vries (IKdV) equation. The primary amplitudes are modulated by two-soliton of the nonlinear Schrődinger (NLS) equation. In this paper, we analyzed the interaction patterns of the two waves packet at the peak interaction. We have shown here, that during under going to the interaction region, the deformation of amplitudes profile will be occurred. The large deformation is characterized by the ratio of the amplitudes parameter and the wave numbers of each wave packets. The symmetry interaction also can be analyzed by the characterization of the parameters.
REFORMULASI DARI SOLUSI 3-SOLITON UNTUK PERSAMAAN KORTEWEG-de VRIES mustikaningsih, Dian; sutimin, sutimin
MATEMATIKA Vol 5, No 2 (2002): Jurnal Matematika
Publisher : MATEMATIKA

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Abstract

The solution of  3-soliton for Korteweg-de Vries (KdV) equation can be obtained by the Hirota Method. The reformulation of the 3-soliton solution was represented as the superposition of the solution of each individual soliton. Moreover, the asymptotic form of 3-soliton solution was obtained by limiting of the t parameter. The phase shift of each individual soliton are analysed in detail based its asymptotic form. The results of the analysis shown that the first soliton always have a phase shift called forward, the second soliton have some possibility (there is no phase shift, have a  forward phase shift, or have a backward phase shift), and for the third soliton always have a phase shift called backward.
Co-Authors Adelina Hasyim Agus Rusgiyono Bayu Surarso Dinita Rahmalia, Dinita Fakhruddin, Muhammad Faraimunashe Chirove Fatkhur Rohim Febriana Dewi hermin ps Hilda Fahlena Imamudin Imamudin Indah Uswatun Juni Wijayanti Puspita Khozin Mu'tamar Lisyani Budipradigda Suromo Muhammad Fakhruddin mustikaningsih, Dian Nuning Nuraini Pukky Tetralian Bantining Ngastiti Redemtus Heru Tjahjana Rohim, Fatkhur Sri Rubiyanti sulanjari, Sulanjari Sunarsih Sunarsih Tarita is Undang Rosidin Yundari, Yundari Zullaikah, Zullaikah