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All Journal CAUCHY: Jurnal Matematika Murni dan Aplikasi Jurnal Kesehatan Manarang J Statistika: Jurnal Ilmiah Teori dan Aplikasi Statistika Contemporary Mathematics and Applications (ConMathA) Jurnal Layanan Masyarakat (Journal of Public Service) Jurnal Pendidikan Matematika Limits: Journal of Mathematics and Its Applications
Ardi Kurniawan
Airlangga University
Humanities Computer Science & IT Decision Sciences, Operations Research & Management Economics, Econometrics & Finance Education Environmental Science Health Professions Materials Science & Nanotechnology Mathematics Nursing Public Health Social Sciences Other

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Estimasi Interval Kredibel Distribusi Normal Terpotong Kiri pada Data Waktu Sembuh Pasien Covid-19 Putri Fardha Asa Oktavia Hans; Ardi Kurniawan; Sediono; Elly Ana; M. Fariz Fadillah Mardianto
J STATISTIKA: Jurnal Imiah Teori dan Aplikasi Statistika Vol 15 No 1 (2022): Jurnal Ilmiah Teori dan Aplikasi Statistika
Publisher : Faculty of Science and Technology, Univ. PGRI Adi Buana Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (232.386 KB) | DOI: 10.36456/jstat.vol15.no1.a5285

Abstract

The Covid-19 pandemic has been declared a Public Health Emergency of International Concern. One of the government's efforts to get out of the epidemic is to conduct an analysis based on existing data. The purpose of this study was to estimate the credible interval of the left truncated normal distribution. The results of the estimated credible intervals obtained have an implicit form so that they are solved by using a numerical integral approach. The results of this study were applied to the recovery time of Covid-19 patients from the Jemursari Health Center Surabaya in the range of December 2020 to February 2021. Through left cutting, the parameter estimation process only uses data that is more than 10 days, so that 37 data is obtained from a total of 45 data. It was found that the average recovery time for left-cut Covid-19 patients was between 10.583 days to 11.087 days. Meanwhile, the variance of recovery time for Covid-19 patients is cut left between 1.706 days to 1.772 days.
Designing Standard Growth Chart Based on Weight-For-Age Z-Score of Children in East Java Using Least-Square Spline Estimator Nur Chamidah; Ardi Kurniawan; Toha Saifudin
Contemporary Mathematics and Applications (ConMathA) Vol. 4 No. 2 (2022)
Publisher : Universitas Airlangga

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20473/conmatha.v4i2.38917

Abstract

Children would be categorized as children who have underweight nutritional status, if according to index of anthropometric they have a lack of weight. In Indonesia, this anthropometric index is recorded on a Card Toward Health called as KMS. This card follows the WHO-2005 standard which is designed based on samples from Brazil, Ghana, India, Norway, Oman, and USA. Those samples, of course, physically are very different from Indonesian children. Therefore, in this paper we design weight-for-age Z-score standard growth charts of children by using least-square spline estimator and samples of children from East Java province, Indonesia. Next, the proposed children standard growth charts are used to assess East Java children nutritional status. The results show that the proposed standard growth charts have met the goodness of fit criteria namely the average values of coefficient determination for boy and girl are close to one, and values of mean square errors are close to zero. It means that the proposed growth charts are more suitable to be used to assess the nutritional status of East Java children, because they can better explain the real conditions of children in East Java, Indonesia than the WHO-2005 standard growth charts.
Analisis Tingkat Kepuasan Masyarakat Terhadap Pelayanan BPJS Kesehatan Cabang Utama Surabaya Dengan Metode Customer Satisfaction Indeks dan Importance Performance Analysis Putri Nur Farida; Ardi Kurniawan; Sediono; Dita Amelia
J STATISTIKA: Jurnal Imiah Teori dan Aplikasi Statistika Vol 16 No 1 (2023): Jurnal Ilmiah Teori dan Aplikasi Statistika
Publisher : Faculty of Science and Technology, Univ. PGRI Adi Buana Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36456/jstat.vol16.no1.a6966

Abstract

Kesehatan merupakan hak asasi manusia dan salah satu unsur kesejahteraan yang harus diwujudkan sesuai cita-cita bangsa Indonesia. Diperlukan pembentukan badan penyelenggara yang berbentuk badan hukum pelayanan publik salah satunya BPJS Kesehatan yang bertujuan untuk memberikan jaminan berupa perlindungan kesehatan kepada masyarakat, serta diharapkan dapat memberikan pelayanan kualitas yang bermutu baik, karena kepuasan merupakan aspek yang paling penting bagi instansi pemerintahan. Penelitian ini bertujuan untuk mengetahui tingkat kepuasan masyarakat terhadap Kantor BPJS Kesehatan dengan data yang digunakan sejumlah 100 responden. Metode yang digunakan yaitu Customer Satisfaction Indeks yang merupakan indeks untuk menentukan tingkat kepuasan pelanggan secara menyeluruh menggunakan pendekatan yang mempertimbangkan tingkat kepentingan dari atribut atribut produk dan jasa yang diukur dan Importance Performance Analysis yang merupakan merupakan salah satu teknik penerapan yang mudah untuk mengatur atribut dari tingkat kepentingan dan tingkat pelaksanaan itu sendiri. Hasil penelitian diperoleh bahwa metode CSI sebesar 82,038 % yang berarti masyarakat merasa sangat puas terhadap pelayanan di Kantor BPJS Kesehatan Cabang Utama Surabaya, pada metode IPA menunjukkan pada kuadran I,II,III,IV masing masing terdapat 11, 1, 9, dan 1 variabel, dan variabel yang pelu ditingkatkan adalah kuadran II, yaitu kecepatan dalam menangani keluhan secara online melalui saluran telepon dan email.
Estimation of Survival Function in Head and Neck Cancer Patients Using the Kaplan-Meier Method Ardi Kurniawan; Adelia Frielady Yosifa; Vrisca Natalia Putri Wardhani; Azizatul Kholidiyah
J STATISTIKA: Jurnal Imiah Teori dan Aplikasi Statistika Vol 16 No 1 (2023): Jurnal Ilmiah Teori dan Aplikasi Statistika
Publisher : Faculty of Science and Technology, Univ. PGRI Adi Buana Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36456/jstat.vol16.no1.a7289

Abstract

Analisis data uji hidup atau analisis survival adalah kumpulan metode statistik yang digunakan untuk menjawab pertanyaan yang berkaitan dengan apakah dan kapan suatu peristiwa terjadi. Data daya tahan hidup yang diperoleh berupa data tersensor tipe I yang dianalisis menggunakan Metode Kaplan-Meier atau Metode Produk Limit. Sampel tersensor tipe I adalah cara pengambilan sampel secara statistik didasarkan pada lama pengamatan yang telah ditentukan sebelumnya. Metode Kaplan-Meier merupakan salah satu metode yang digunakan untuk mengestimasi fungsi survival dalam analisis data uji hidup. Penelitian ini bertujuan untuk mengestimasi daya tahan hidup seorang penderita kanker kepala dan leher. Kanker kepala dan leher adalah jenis kanker yang paling umum di dunia dan terdiri dari berbagai kelompok tumor yang mempengaruhi saluran aerodigestive bagian atas. Penelitian dimulai dengan menentukan data tersensor dan tipe sensor, kemudian menghitung estimasi fungsi survivor. Fungsi survivor merupakan probabilitas individu atau suatu objek tertentu untuk tetap bertahan setelah melewati suatu satuan waktu. Data pada penelitian ini adalah Data Kanker Kepala dan Leher Northern California Oncology Group. Kelompok pasien kanker kepala leher diobati dengan terapi radiasi plus kemoterapi (RCT) dengan 45 pasien. Hasil penelitian menunjukkan bahwa pasien kanker kepala dan leher yang menjalani pengobatan RCT memiliki peluang bertahan hidup semakin kecil seiring berjalannya waktu.
Survival Analysis and Hazard of Log Logistic Distribution on Type I Censored Data Parametrically Ardi Kurniawan; Ruth Hosana; Ni Wayan Widya Septia Sari
Contemporary Mathematics and Applications (ConMathA) Vol. 5 No. 2 (2023)
Publisher : Universitas Airlangga

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20473/conmatha.v5i2.47040

Abstract

Survival Analysis is a research method that examines the survival time of individuals or experimental units in relation to events such as death, disease, recovery, or other experiences. This study utilizes a parametric survival analysis model with a 2 parameter log logistic distribution and Maximum Likelihood Estimation (MLE) method to analyze the survival of students during their study period. The log logistic distribution is chosen due to its ability to capture early or late failure patterns. The objective of this research is to analyze type I censored survival data using the log logistic distribution applied to secondary data on student study duration. The dataset consists of 98 observations. The calculated values for the β and γ parameters of the 2 parameters log logistic distribution are 2.12831 and 0.0918891, respectively. The probability of students completing their studies by semester 8 (hazard function h(8)) is 0.370102, while the probability of students continuing their studies in semester 9 (survival function s(9)) is 0.320817.
Analisis Survival Distribusi Lomax dengan Estimasi Maximum Likelihood Victoria Anggia Alexandra; Aprilia Prastyaningrum; Ardi Kurniawan; Dita Amelia
Limits: Journal of Mathematics and Its Applications Vol. 22 No. 1 (2025): Limits: Journal of Mathematics and Its Applications Volume 22 Nomor 1 Edisi Ma
Publisher : Pusat Publikasi Ilmiah LPPM Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/limits.v22i1.3373

Abstract

Survival analysis is a statistical technique used to test the durability and reliability of a component. Life time data obtained from a life test experiment is often in the form of type III censored data, which occurs when observations enter at different times and last for varying durations. In survival analysis, data is expected to follow a certain probability distribution. To determine the characteristics of a population, a point estimate of the probability distribution parameters is conducted. This study aims to obtain parameter estimators of the Lomax distribution on type III censored data with the Maximum Likelihood Estimation (MLE) and Newton Raphson methods. Application of parameter estimation results on post-heart surgery survival data in one of the Jakarta hospitals. The result of estimating the parameter value in the post-heart surgery patient data is 1.552 and the result of estimating the parameter in the post-heart surgery patient data is 20.38. Based on these results, it can be concluded that the estimated probability of survival of a post-heart surgery patient for more than 49 days is 14.94%.
Indeks Pembangunan Gender Indonesia dalam Perspektif Pendekatan Spasial dengan Pembobot Queen Contiguity Dita Amelia; Made Riyo Ary Permana; Adelia Frielady Yosifa; Ardi Kurniawan; Suliyanto
Limits: Journal of Mathematics and Its Applications Vol. 21 No. 2 (2024): Limits: Journal of Mathematics and Its Applications Volume 21 Nomor 2 Edisi Ju
Publisher : Pusat Publikasi Ilmiah LPPM Institut Teknologi Sepuluh Nopember

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

Abstract

Isu gender menjadi fokus global karena ketimpangan dalam hak-hak dan kontribusi laki-laki dan perempuan dalam pembangunan. Pencapaian Indeks Pembangunan Gender (IPG) menjadi tolok ukur penting dalam upaya mencapai kesetaraan gender dan pembangunan manusia yang inklusif di Indonesia. Penelitian ini bertujuan untuk memodelkan Indeks Pembangunan Gender di Indonesia dengan pendekatan regresi spasial dengan variabel-variabel yang diduga mempengaruhi IPG. Metode yang digunakan dalam penelitian ini adalah regresi spasial dengan pembobot Queen Contiguity . Berdasarkan penelitian yang telah dilakukan dengan tiga jenis pemodelan didapatkan model terbaik dalam pemodelan Indeks Pembangunan Gender di Indonesia adalah model regresi spasial error dengan nilai AIC sebesar 154,950 dan nilai R 2 sebesar 0,6643. Analisis spasial mengungkapkan adanya korelasi dan heterogenitas spasial antar wilayah, menyoroti pentingnya mempertimbangkan aspek spasial dalam merancang kebijakan untuk meningkatkan pembangunan gender di Indonesia. Dengan demikian, upaya perbaikan dan kesetaraan gender sebaiknya diterapkan dengan mempertimbangkan variabilitas spasial serta fokus pada aspek-aspek yang telah diidentifikasi melalui pemodelan ini.
Step-Stress Accelerated Life Testing with Type II Censoring and Exponential Distribution for Solar-Powered Lighting Systems Ardi Kurniawan; Vanisia Suci Ananda; Yovita Karin Kalista
CAUCHY: Jurnal Matematika Murni dan Aplikasi Vol 11, No 1 (2026): 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/cauchy.v11i1.41076

Abstract

This study addresses the reliability assessment of solar-powered lighting systems using a partial step-stress accelerated life testing (ALT) model with Type-II censoring. The research aims to estimate the mean failure time and quantify the acceleration effect due to elevated stress. Secondary data from an experiment involving 31 lighting devices were analyzed. Initially, devices were tested at a normal temperature (293 K) until 16 failures occurred. Subsequently, the stress was increased to 353 K, and testing continued until all units failed or were censored. Under the assumption of an exponential lifetime distribution and a linear accelerated failure-time model, the maximum likelihood estimation (MLE) method was applied for parameter inference. The results show that the estimated mean failure time under normal conditions is approximately 711.6 hours, which reduces to about 38.7 hours under accelerated stress, yielding an acceleration factor of 18.354. Furthermore, a 95% confidence interval for the mean failure time under normal conditions is between 460.2 and 1245 hours. The reliability and percentile life at various stress levels were also derived. This research provides a practical statistical framework for evaluating the reliability of solar-powered lighting devices, offering a more efficient alternative to conventional life testing methods.
Two-Parameter Exponential Estimation via EM Algorithm: Uterine Leiomyosarcoma Survival Risk Analysis Ardi Kurniawan; Deby Victoria; Christabel Lee Angie Sugianto
CAUCHY: Jurnal Matematika Murni dan Aplikasi Vol 11, No 1 (2026): 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/cauchy.v11i1.41855

Abstract

Accurate survival prognosis is critical for clinical decision-making, yet analyzing censored on cological data remains a statistical challenge. This study aims to implement the Expectation Maximization (EM) algorithm for the two-parameter exponential distribution to estimate parameters and forecast extreme survival risks in uterine leiomyosarcoma (uLMS). Using clinical data from 122 patients, the EM algorithm achieved rapid convergence after 19 it erations, yielding a scale parameter of 68.7037 months and a 2-month survival threshold. Statistical validity was confirmed by a Kolmogorov-Smirnov test (p = 0.2084) and a 94.5% coverage probability from Monte Carlo simulations. A key contribution of this research is the integration of Value-at-Risk (VaR) and Tail Value-at-Risk (TVaR) metrics, which identified a 95% survival threshold of 207.82 months. Sensitivity analysis further demonstrated the es timator’s structural stability across varying censoring proportions. These results signify that the proposed framework provides a robust and reliable tool for quantifying extreme survival probabilities, offering clinicians a sophisticated method for long-term risk management and personalized patient prognosis.
Modeling Of Influential Factors On Dengue Fever Incidence In Indonesia Using The Multivariate Adaptive Regression Spline Method: A Case Study In East Java Province Ardi Kurniawan; Sabrina Salsa Oktavia; Nabila Shafa Aflaha
Jurnal Kesehatan Manarang Vol 12 No 1 (2026): April 2026
Publisher : Politeknik Kesehatan Kemenkes Mamuju

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33490/jkm.v12i1.2009

Abstract

Indonesia, as a tropical country, continues to face mosquito-borne diseases, particularly Dengue Fever (DF), transmitted by the Aedes aegypti mosquito. This disease remains a significant public health issue, with fluctuating but generally high incidence rates across various regions. MARS (Multivariate Adaptive Regression Splines) is a non-parametric regression method that is adaptive in modeling non-linear relationships between dependent and independent variables and is capable of capturing interactions among independent variables. The best MARS model is one that has the lowest Generalized Cross Validation (GCV) and Mean Square Error (MSE) values. This study employs a quantitative approach using secondary data obtained from the 2023 Indonesia Health Survey Report. The MARS model for Dengue Fever prevalence in Indonesia is as follows: Y = 0.522 + 0.157 × BF1 – 0.046 × BF3 + 0.272 × BF8 + 0.038 × BF10 – 0.018 × BF12. The proportion of households without trash bins is the most influential factor affecting Dengue Fever prevalence in Indonesia, with an importance level of 100%. This is followed by the proportion of households not implementing mosquito control efforts, with an importance level of 37.811%, and the proportion of households without handwashing facilities, with an importance level of 35.669%. By inserting the Basis Function values into the model equation, it was concluded that the Dengue Fever prevalence in East Java Province (Y = 0.3881) is lower compared to the national prevalence in Indonesia (Y = 0.522) because variables X3 and X5 have lower values.
Co-Authors Adelia Frielady Yosifa Adelia Frielady Yosifa Ana, Elly Aprilia Prastyaningrum Arinda Mahadesyawardani Aurellia Calista Anggakusuma Azizatul Kholidiyah Christabel Lee Angie Sugianto Deby Victoria Dita Amelia Dwika Maya Harsanti Fa’iqotus Zuqna Dwi Syauqie Hanny Valida M. Fariz Fadillah Mardianto Made Riyo Ary Permana Mia Khoirunnisa Nabila Shafa Aflaha Nathania Fauziah Naufal Ramadhan Al Akhwal Siregar Ni Wayan Widya Septia Sari Nur Chamidah Putri Fardha Asa Oktavia Hans Putri Nur Farida Raaulia Gita Nafsi Ruth Hosana Sabrina Salsa Oktavia Salsabylla Nada Apsariny Sediono, Sediono Suliyanto Syifa’ Azizah Putri Gunawan Toha Saifudin Vanisia Suci Ananda Verina Tita Nabila Victoria Anggia Alexandra Vrisca Natalia Putri Wardhani Yovita Karin Kalista