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All Journal CAUCHY: Jurnal Matematika Murni dan Aplikasi Jurnal Pendidikan Ekonomi & Bisnis Desimal: Jurnal Matematika BAREKENG: Jurnal Ilmu Matematika dan Terapan Jurnal Aplikasi Statistika & Komputasi Statistik Journal of Mathematics, Computation and Statistics (JMATHCOS)
Valentika, Nina
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Computer Science & IT Control & Systems Engineering Decision Sciences, Operations Research & Management Economics, Econometrics & Finance Education Energy Engineering Mathematics Mechanical Engineering Physics Social Sciences Transportation

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The Confidence Interval of the Estimator of the Periodic Intensity Function in the Presence of Power Function Trend on the Nonhomogeneous Poisson Process Maulidi, Ikhsan; Wibowo, Bonno Andri; Valentika, Nina; Syazali, Muhammad; Apriliani, Vina
CAUCHY Vol 7, No 1 (2021): CAUCHY: Jurnal Matematika Murni dan Aplikasi
Publisher : Mathematics Department, Maulana Malik Ibrahim State Islamic University of Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18860/ca.v7i1.12848

Abstract

The nonhomogeneous Poisson process is one of the most widely applied stochastic processes. In this article, we provide a confidence interval of the intensity estimator in the presence of a periodic multiplied by trend power function. This estimator's confidence interval is an application of the formulation of the estimator asymptotic distribution that has been given in previous studies. In addition, constructive proof of the convergent in probability has been provided for all power functions.
Performance Study of Prediction Intervals with Random Forest for Poverty Data Analysis Valentika, Nina; Notodiputro, Khairil Anwar; Sartono, Bagus
Jurnal Aplikasi Statistika & Komputasi Statistik Vol 16 No 1 (2024): Jurnal Aplikasi Statistika & Komputasi Statistik
Publisher : Politeknik Statistika STIS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.34123/jurnalasks.v16i1.542

Abstract

Introduction/Main Objectives: Determine the prediction interval with for analyzing poverty data at the Regency/City level in Indonesia. Background Problems: Poverty will be a topic in various discussion and debates in the future. Novelty: This study’s methods for constructed prediction intervals are LM, Quant, SPI, HDR, and CHDR. This method can improve the prediction interval performance with Random Forests. Research Methods: The method for building forests and obtaining BOP in this study is CART with the LS splitting rule. Finding/Results: The results of this study are that the best method for one replication is HDR with 500 trees. The best method for 100 repetitions is LM. Based on hypothesis testing, there is sufficient evidence to say no difference between the LM, SPI, Quant, HDR, and CHDR methods for 100 replications at a 5% significance level.
Entrepreneurial Intention Among Students: The Effect of Self-efficacy and Entrepreneurial Attitude Nursyirwan, Vivi Iswanti; Purwana, Dedi; Suhud, Usep; Harahap, Irwan Leo Putra; Valentika, Nina
Jurnal Pendidikan Ekonomi Dan Bisnis (JPEB) Vol 10 No 2 (2022): Jurnal Pendidikan Ekonomi & Bisnis (DOAJ & SINTA 2 Indexed)
Publisher : Faculty of Economics, State University of Jakarta, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/JPEB.010.2.8

Abstract

To escalate the number of university students’ entrepreneurs, it is important to understand the role of self-efficacy and entrepreneurial attitude. The goal of this study is to investigate the role of self-efficacy in influencing students’ entrepreneurial attitudes and intentions. This study also examines the effect of entrepreneurial attitudes linked with students’ entrepreneurial intentions. The study used a cross-sectional survey design with a purposive sample of 100 university students at Universitas Pamulang in Indonesia. Structural Equation Modeling-Partial Least Square (SEM-PLS) is used to the connectivity among the independent–dependent variables in the research. The results of the study found that entrepreneurial self-efficacy had a significant positive effect on the entrepreneurial intentions of university students. In addition, attitudes towards entrepreneurship have a significant positive effect on entrepreneurial intentions. Indeed, entrepreneurial self-efficacy has a positive effect on attitudes towards entrepreneurship, and a significant influence is obtained between entrepreneurial self-efficacy on entrepreneurial intentions and attitudes towards entrepreneurship as an intervening variable
Faktor-Faktor yang Mempengaruhi Risiko Saham dengan Menggunakan Regresi Logistik Ordinal Valentika, Nina; Sumertajaya, I Made; Azis, Irfani; Nunung Kusdaniyama
Journal of Mathematics, Computations and Statistics Vol. 7 No. 1 (2024): Volume 07 Nomor 01 (April 2024)
Publisher : Jurusan Matematika FMIPA UNM

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35580/jmathcos.v7i1.1962

Abstract

Abstrak. Tujuan dalam penelitian ini adalah untuk mengetahui kategori risiko pada saham dengan menggunakan beta saham, serta membandingkan model regresi logistik ordinal tanpa efek interaksi dan dengan efek interaksi untuk mengetahui faktor-faktor yang mempengaruhi risiko saham. Hasil penelitian yang diperoleh adalah model terbaik yang diperoleh adalah Untuk rendah|sama Untuk sama|tinggi Ukuran dari koefisien determinasi (R-Square) yang digunakan dalam pengujian kebaikan model adalah Negelkerke yaitu sebesar 66,80%. Variabel yang berpengaruh terhadap risiko saham adalah return pada taraf nyata 10%.
Perbandingan Regresi Data Panel Variabel Perdagangan berdasarkan Periode Data Selama Pandemi Covid-19 Valentika, Nina; Sumertajaya, I Made; Kusdaniyama, Nunung; Sunardi
Journal of Mathematics, Computations and Statistics Vol. 6 No. 1 (2023): Volume 06 Nomor 01 (April 2023)
Publisher : Jurusan Matematika FMIPA UNM

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

The purpose of this study is to model the effect of returns and trading volume on the bid-ask spread using monthly and annual data during the Covid-19 Pandemic, as well as compare the panel data regression model to see the effect of returns and trading volume on the bid-ask spread based on monthly data periods and annually during the Covid-19 Pandemic. The results showed that the best model for monthly and annual data during the Covid-19 Pandemic was a random effect data model with individual effects or cross sections. In the random effect data model with individual effects or cross-section for monthly data, it is found that volume has a significant effect on the bid-ask spread at a significant level of 5%. Meanwhile, for annual data, it is found that returns have a significant effect on the bid-ask spread at a significant level of 5%. The best model based on monthly and annual data periods is the random effects data model with individual effects or cross sections using annual data.
An Analysis of the Effect of Utilitarian Values on Shopee E-Commerce Satisfaction and Loyalty with SEM-PLS Valentika, Nina
Desimal: Jurnal Matematika Vol. 3 No. 2 (2020): Desimal: Jurnal Matematika
Publisher : Universitas Islam Negeri Raden Intan Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24042/djm.v3i2.5939

Abstract

This research examines Shopee consumers who have shopped at least once and are students in the Department of Accounting, Faculty of Economics, Pamulang University. The method used was the Structural Equation Modeling-Partial Least Square (SEM-PLS). The purpose of this research was to examine the direct effect of utilitarian values on satisfaction, examine the direct effect of satisfaction on loyalty, and examine the indirect effect of utilitarian values on loyalty. Based on the results of the research, it can be concluded that there was a significant influence on satisfaction and loyalty, utilitarian values, and satisfaction, as well as utilitarian values and loyalty. There was a significant influence of Utilitarian values and loyalty with satisfaction as an intervening variable.
Structural equation modeling-partial least squares: Analysis of the effect of hedonic value on customer satisfaction and loyalty Nursyirwan, Vivi Iswanti; Valentika, Nina
Desimal: Jurnal Matematika Vol. 4 No. 1 (2021): Desimal: Jurnal Matematika
Publisher : Universitas Islam Negeri Raden Intan Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24042/djm.v4i1.5948

Abstract

Testing the effect of hedonic value on loyalty, the hedonic value on satisfaction, and customer satisfaction on consumer loyalty, and investigating the effect of hedonic value on consumer loyalty with customer satisfaction as an intervening variable is the purpose of this study, with a case study on e-commerce Shopee.  The sample aims to be a method of determining the sample with a total of 100 respondents. The intended respondents are Pamulang University students, Faculty of Economics, S1 Accounting Department as well as consumers of Shopee e-commerce. The Research model used SEM-PLS Structural Equation Modeling-Partial Least Square Approach. The results of this study indicate that the hedonic value has a positive influence and also has a significant value on consumer loyalty at the real level of 10%. The results of the study also state hedonic value has a significant positive effect on consumer satisfaction, and customer satisfaction has a significant positive effect on consumer loyalty with the satisfaction of consumer as a variable of intervening with 10% level.
Modeling The Relationships Between Export, Import, Inflation, Interest Rate, and Rupiah Exchange Valentika, Nina; Nursyirwan, Vivi Iswanti; Ilmadi, Ilmadi
Desimal: Jurnal Matematika Vol. 3 No. 3 (2020): Desimal: Jurnal Matematika
Publisher : Universitas Islam Negeri Raden Intan Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24042/djm.v3i3.6942

Abstract

This research was a modification of research by Catalbas (2016) and Pratikto (2012). The model that can separate long-term and short-term components are the Vector Error Correction Model (VECM). This study aimed to model export, import, inflation, interest rates, and the rupiah exchange rate using VECM and to test the causality between variables using the Granger Causality test. The inter-variable model obtained in this study was VECM with lag 2 using a deterministic trend with the assumption of none intercept no trend and two cointegrations. In export and import, there was an adjustment mechanism from the short-term to the long-term. This research model was appropriate to forecast the export and import where VECM with export and import as the target variables, the cointegration equation (long-run model) for  cointegration equation (long-run model) for Based on the Granger Causality test, it was found that there was a one-way relationship between exchange rates and inflation, export and interest rates, export and import, inflation and export, and import and the interest rate at the significance level of 5%.
ANALYSIS OF OPTIMUM CONTROL ON THE IMPLEMENTATION OF VACCINATION AND QUARANTINE ON THE SPREAD OF COVID-19 Nuha, Agusyarif Rezka; Achmad, Novianita; Rahman, Gusti Arviana; Abdullah, Syarif; Chasanah, Sri Istiyarti Uswatun; Valentika, Nina; Nashar, La Ode
BAREKENG: Jurnal Ilmu Matematika dan Terapan Vol 16 No 4 (2022): BAREKENG: Journal of Mathematics and Its Applications
Publisher : PATTIMURA UNIVERSITY

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (426.143 KB) | DOI: 10.30598/barekengvol16iss4pp1139-1146

Abstract

This study constructs an SVIR-type COVID-19 spread model into a model with control variables or optimum control problems. In the formulation of the model with controls, we set four control variables, namely vaccination strategy, quarantine, reduction of vaccine shrinkage, and treatment. Pontryagin 's maximum principle is applied in the model as a sufficient condition to achieve optimum conditions for minimizing the objective function . This study uses a numerical solution to describe the theoretical results. The results showed that the control model could accelerate the decrease in the number of individuals in the infected population class. We found that vaccination is a top priority that needs to be done to reduce the number of cases of COVID-19 infection. In addition, the implementation of quarantine can also be considered to accelerate the decrease in the number of individuals infected with COVID-19.
Co-Authors Agusyarif Rezka Nuha Azis, Irfani Bagus Sartono Chasanah, Sri Istiyarti Uswatun Harahap, Irwan Leo Putra I Made Sumertajaya Ilmadi, Ilmadi Kusdaniyama, Nunung La Ode Nashar Maulidi, Ikhsan Nunung Kusdaniyama Nursyirwan, Vivi Iswanti Purwana E.S., Dedi Rahman, Gusti Arviana Sunardi Syarif Abdullah Syazali, Muhammad Usep Suhud Vina Apriliani Wibowo, Bonno Andri