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Contact Name
Dr. Windarto
Contact Email
windarto@fst.unair.ac.id
Phone
+62315936501
Journal Mail Official
conmatha@fst.unair.ac.id
Editorial Address
Study Program of Mathematics, Department of Mathematics, Faculty of Science and Technology, Universitas Airlangga, Indonesia Kampus C UNAIR Jl. Mulyorejo Surabaya, Jawa Timur 60115
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Kota surabaya,
Jawa timur
INDONESIA
Contemporary Mathematics and Applications
Published by Universitas Airlangga
ISSN : -     EISSN : 26865564     DOI : -
Core Subject : Education,
Contemporary Mathematics and Applications welcome research articles in the area of mathematical analysis, algebra, optimization, mathematical modeling and its applications include but are not limited to the following topics: general mathematics, mathematical physics, numerical analysis, combinatorics, optimization and control, operation research, statistical modeling, mathematical finance and computational mathematics.
Articles 15 Documents
SOLVING CLOSE-OPEN MIXED VEHICLE ROUTING PROBLEM USING BAT ALGORITHM Amalia, Atika Dwi Hanun; Suprajitno, Herry; Pratiwi, Asri Bekti
Contemporary Mathematics and Applications Vol 2, No 1 (2020)
Publisher : Universitas Airlangga

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (636.526 KB) | DOI: 10.20473/conmatha.v2i1.19301

Abstract

The purpose of this research is to solve the Close-Open Mixed Vehicle Routing Problem (COMVRP) using Bat Algorithm. COMVRP which is a combination of Close Vehicle Routing Problem or commonly known as Vehicle Routing Problem (VRP) with Open Vehicle Routing Problem (OVRP) is a problem to determine vehicles route in order to minimize total distance to serve customers without exceed vehicle capacity. COMVRP occurs when the company already has private vehicles but its capacity could not fulfill all customer demands so the company must rent several vehicles from other companies to complete the distribution process. In this case, the private vehicle returns to the depot after serving the last customer while the rental vehicle does not need to return. Bat algorithm is an algorithm inspired by the process of finding prey from small bats using echolocation. The implementation program to solve was created using Java programming with NetBeans IDE 8.2 software which was implemented using 3 cases, small data with 18 customers, medium data with 75 customers and large data with 100 customers. Based on the implementation results, it can be concluded that the more iterations, the smaller total costs are obtained, while for the pulse rate and the amount of bat tends not to affect the total cost obtained.
ANALISIS PENGARUH ANGKA KEMATIAN BAYI TERHADAP ANGKA HARAPAN HIDUP DI PROVINSI JAWA TIMUR BERDASARKAN ESTIMATOR LEAST SQUARE SPINE W, Anies Yulinda; L., Trias Novia; Tegarina, Melati; Chamidah, Nur
Contemporary Mathematics and Applications Vol 1, No 1 (2019)
Publisher : Universitas Airlangga

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (652.916 KB) | DOI: 10.20473/conmatha.v1i1.14775

Abstract

Life expectancy can be used to evaluate the government's performance for improving the welfare of the population in the health sector. Life expectancy is closely related to infant mortality rate. Theoretically, decreasing of infant mortality rate will cause increasing of life expectancy. A statistical method that can be used to model life expectancy is nonparametric regression model based on least square spline estimator. This method provides high flexibility to accommodate pattern of data by using smoothing technique. The best estimated model is order one spline model with one knot based on minimum generalized cross validation (GCV) value of 0.607. Each increasing of one infant mortality rate unit will cause decreasing of life expectancy of  0.2314 for infant mortality rate less than 27, and of  0.0666 for infant mortality rate more than and equals to 27. In addition, based on mean square error (MSE) of 0.492 and R2value of 76.59% for nonparametric model approach compared with MSE of 0.634 and R2 value of 71.8%  for parametric model approach, we conclude that the use of nonparametric model approach based on least square spline estimator is better than that of parametric model approach.
HYBRID ARTIFICIAL NEURAL NETWORK WITH EXTREME LEARNING MACHINE METHOD AND CUCKOO SEARCH ALGORITHM TO PREDICT STOCK PRICES Prabawati, Piping; Damayanti, Auli; Suprajitno, Herry
Contemporary Mathematics and Applications Vol 1, No 2 (2019)
Publisher : Universitas Airlangga

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (654.116 KB) | DOI: 10.20473/conmatha.v1i2.17387

Abstract

This thesis aims to predict the stock prices, using artificial neural network with extreme learning machine (ELM) method and cuckoo search algorithm (CSA). Stock is one type of investment that is in great demand in Indonesia. The portion ownership of stock is determined by how much investment is invested in the company. In this case, stock is an aggressive type of investment instrument, because stock prices can change over time. In this case, ELM is used to determine forecasting values, while CSA is applied to compile and optimize the values of weights and biases to be used in the forecasting process. After obtaining the best weights and biases, the validation test process is then carried out to determine the level of success of the training process. The data used is the daily data of the stock price of PT. Bank Mandiri (Persero) Tbk. the total is 291 data. Furthermore, the data is divided into 70% for the training process is as many as 199 data and 30% for the validation test as many as 87 data. Then compiled pattern of training and validation test patterns is 198 patterns and 82 patterns. Based on the implementation of the program, with several parameter obtained the result of  MSE training is 0.001304353, with an MSE of validation test is 0.0031517704. Because the MSE value obtained is relatively small, this indicates that the ELM-CSA network is able to recognize data patterns and is able to predict well.
PENERAPAN ALGORITMA KUNANG-KUNANG PADA OPEN VEHICLE ROUTING PROBLEM (OVRP) Septiyafi, Ihda; Suprajitno, Herry; Pratiwi, Asri Bekti
Contemporary Mathematics and Applications Vol 1, No 1 (2019)
Publisher : Universitas Airlangga

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (374.67 KB) | DOI: 10.20473/conmatha.v1i1.14774

Abstract

This paper aims to solve Open Vehicle Routing Problem using Firefly Algorithm. Open Vehicle Routing Problem (OVRP) is a variant of Vehicle Routing Problem (VRP)  where vehicles used to serve customers do not return to the depot after serving the last customer on each route. The steps of the Firefly Algorithm to handle OVRP are data input and initialization parameters, generating the initial population for each firefly, sorting population sources, calculating the value of the objective function and light intensity, comparing the intensity of light, performing movement, setting the best fireflies as g-best, doing random movement in the best fireflies as long as the maximum number of iterations has not been met. The program used to complete OVRP using the Firefly Algorithm is Borland C ++ and implemented in 3 case examples, namely small data with 18 customers, moderate data with 50 customers, and large data with 100 customers with the best total mileage of 211, 344 , 970.62, and 2531.83. The results obtained from the program output indicate that the more the number of iterations and the number of fireflies, then the results of the objective function (total mileage) obtained tend to be better so that these parameters affect the value of the objective function. While the absorption coefficient value (g) does not give effect to the value of the objective function.
ANALISIS KESTABILAN DAN KONTROL OPTIMAL MODEL MATEMATIKA DINAMIKA PELANGGAN BERDASARKAN KEBIJAKAN PEMASARAN Farchan, Muhammad Iqbal Abdi; Fatmawati, Fatmawati; Alfiniyah, Cicik
Contemporary Mathematics and Applications Vol 2, No 1 (2020)
Publisher : Universitas Airlangga

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (706.178 KB) | DOI: 10.20473/conmatha.v2i1.19300

Abstract

Customer dynamics include the exchange of information and ongoing transactions between customers and the organization. This process has an important role in the company to run its business, so that the number of customers increase. To achieve this, many things are done by the company. One of the strategies is product advertising by word of mouth. The purpose of this thesis is to analyze the stability of equilibrium point and to apply the optimal control word of mouth advertising on mathematics model of the customer dynamics based on marketing policy. Mathematics model of the customer dynamics based on marketing policy without control has two equilibrium points, namely non ? endemic equilibrium (E0) and endemic equilibrium (E1). Local stability of equilibrium and the existence of endemic equilibrium depends on basic reproduction number (R0). The non ? endemic equilibrium tend to asymptotically stable if R0 < 1.  The problem of optimal control is solved by Pontryagin?s Maximum Principle. The simulation results show that the total number of referral and regular customer populations that are given control in the form of word of mouth advertising efforts at the end of the observation are 312 and 18470 with the control effort costs occurred in 1798364.63. While the total number of referral and regular customer populations that are not given control in the form of word of mouth advertising efforts at the end observation are 241 and 17260. Based on these results show that word of mouth advertising efforts have an effect to increase the number of referral and regular customer in accordance with the aim of providing optimal control.
ANALISIS KONTROL OPTIMAL MODEL MATEMATIKAN PENYEBARAN PENYAKIT MOSAIC PADA TANAMAN JARAK PAGAR Pambudi, Adiluhung Setya; Fatmawati, Fatmawati; Windarto, Windarto
Contemporary Mathematics and Applications Vol 1, No 2 (2019)
Publisher : Universitas Airlangga

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (573.289 KB) | DOI: 10.20473/conmatha.v1i2.17386

Abstract

Mosaic disease is an infectious disease that attacks Jatropha curcas caused by Begomoviruses. Mosaic disease can be transmitted through the bite of a whitefly as a vector. In this paper, we studied a mathematical model of mosaic disease spreading of Jatropha curcas with awareness effect. We also studied the effect of prevention and extermination strategies as optimal control variables. Based on the results of the model analysis, we found two equilibriums namely the mosaic-free equilibrium and the endemic equilibrium. The stability of equilibriums and the existence of endemic equilibrium depend on basic reproduction number ( ). When , the spread of mosaic disease does not occur in the population, while when , the spread of mosaic disease occurs in the population. Furthermore, we determined existence of the optimal control variable by Pontryagin's Maximum Principle method. Simulation results show that prevention and extermination have a significant effect in eliminating mosaic disease.
PENERAPAN CUCKOO SEARCH ALGORITHM (CSA) UNTUK MENYELESAIKAN UNCAPACITATED FACILITY LOCATION PROBLEM (UFLP) Pratiwi, Asri Bekti; Faiza, Nur; Edi Winarko, Edi
Contemporary Mathematics and Applications Vol 1, No 1 (2019)
Publisher : Universitas Airlangga

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (355.693 KB) | DOI: 10.20473/conmatha.v1i1.14773

Abstract

The aim of this research is to solve Uncapacitated Facility Location Problem (UFLP) using Cuckoo Search Algorithm (CSA). UFLP involves n locations and facilities to minimize the sum of the fixed setup costs and serving costs of m customers. In this problem, it is assumed that the built facilities have no limitations in serving customers, all request from each customers only require on facility, and one location only provides one facility. The purpose of the UFLP is to minimize the total cost of building facilities and customer service costs. CSA is an algorithm inspired by the parasitic nature of some cuckoo species that lay their eggs in other host birds nests. The Cuckoo Search Algorithm (CSA) application  program for resolving Uncapacitated Facility Location Problems (UFLP) was made by using Borland C ++ programming language implemented in two sample cases namely small data and big data. Small data contains 10 locations and 15 customers, while big data consists 50 locations and 50 customers. From the computational results, it was found that higher number of nests and iterations lead to minimum total costs. Smaller value of pa brought to better solution of UFLP.
HUBUNGAN DIMENSI METRIK KETETANGGAAN DAN DIMENSI METRIK KETETANGGAN LOKAL GRAF HASIL OPERASI KALI KORONA Rahmayanti, Virdina; Utoyo, Moh. Imam; Susilowati, Liliek
Contemporary Mathematics and Applications Vol 2, No 1 (2020)
Publisher : Universitas Airlangga

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (414.976 KB) | DOI: 10.20473/conmatha.v2i1.19299

Abstract

Adjacency metric dimension and local adjacency metric dimension are the development of metric dimension. The purpose of this research is to determine the adjacency metric dimension of corona graph between any connected graph G and non-trivial graph H denoted by dimA(G?H), to determine the local adjacency metric dimension of corona graph between any connected graph G and non-trivial graph H denoted by dimA,l(G?H), and to determine the correlation between adjacency metric dimension and local adjacency metric dimension of corona product graph operations. In this research, it is found out that the value of adjacency metric dimension of G?H graph is affected by the basic characteristic of H and the domination characteristic. Meanwhile, the value of local adjacency metric dimension of G?H graph is only affected by the basic characteristic of H Futhermore, it is found a correlation of adjacency metric dimension and local adjacency metric dimension of corona product graph between any connected graph G and non-trivial graph H.
ANALISIS KESTABILAN MODEL MATEMATIKA KO-INFEKSI VIRUS INFLUENZA A DAN PNEUMOKOKUS PADA SEL INANG Anwar, Abdul Faliq; Windarto, Windarto; Alfiniyah, Cicik
Contemporary Mathematics and Applications Vol 1, No 2 (2019)
Publisher : Universitas Airlangga

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (780.616 KB) | DOI: 10.20473/conmatha.v1i2.17385

Abstract

Co-infection of influenza A virus and pneumococcus is caused by influenza A virus and pneumococcus bacteria which infected host cell at the same time. The purpose of this thesis is to analyze stability of equilibrium point on mathematical model within-host co-infection of influenza A and pneumococcus. Based on anlytical result of the model there are four quilibrium points, non endemic co-infection equilibrium (E0), endemic influenza A virus equilibrium (E1), endemic pneumococcus equilbrium (E2) and endemic co-infection equilibrium (E3). By Next Generation Matrix (NGM), we obtain two basic reproduction number, which are basic reproduction number for influenza A virus (R0v) and basic reproduction number for pneumococcus (R0b). Existence of equilibrium point and local stability of equilibrium point dependent on basic reproduction number. Non endemic co-infection equilibrium is locally asymtotically stable if R0v < 1 and R0b < 1; influenza A virus endemic equilibrium is locally asymtotically stable if R0v > 1 and R0b > 1; pneumococcus endemic equilibrium is locally asymtotically stable if R0v < 1 and R0b > 1. Meanwhile, the co-infection endemic equilibrium is locally asymtotically stable if R0v > 1 and R0b > 1. From the numerical simulation result, it was shown that increasing the number of influenza A virus and pneumococcus made the number of population cell infected by influenza A virus and pneumococcus (co-infection) also increased.
KETAKSAMAAN HADAMARD PADA FUNGSI KONVEKS Irawan, Rivanxander; Eridani, Eridani; Jaelani, Abdulloh
Contemporary Mathematics and Applications Vol 2, No 1 (2020)
Publisher : Universitas Airlangga

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (361.12 KB) | DOI: 10.20473/conmatha.v2i1.19295

Abstract

Pada penelitian ini, akan dibahas sifat-sifat fungsi gamma dan hubungannya dengan fungsi konveks. Selanjutnya akan ditinjau bentuk ketaksamaan Hadamard pada fungsi konveks. Fungsi konveks adalah fungsi dengan sifat garis yang menghubungkan dua titik di kurvanya akan selalu di atas kurva tersebut. Berdasarkan hasil pembahasan, didapatkan fakta bahwa fungsi gamma  merupakan fungsi yang bersifat log konveks. Selain itu, diperoleh bentuk umum ketaksamaan Hadamard untuk fungsi p-konveks dengan p>0.

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