Judul: Aerosol Spatial Variation and Its  Relationship with Extreme Rainfall in Indonesia
Abstrak: Curah hujan merupakan salah satu unsur iklim yang terpengaruh oleh perubahan iklim seperti perubahan pola curah hujan, peningkatan intensitas curah hujan, dan peningkatan frekuensi kejadian ekstrem. Salah satu faktor penyebab terjadinya curah hujan adalah aerosol. Aerosol memiliki peran penting dalam iklim global melalui dua mekanisme, yaitu langsung dan tidak langsung. Penelitian ini bertujuan menganalisis korelasi spasial dan pengaruh variasi aerosol terhadap curah hujan di wilayah Indonesia tahun 1990-2019 dan mengetahui tren tahunan aerosol dengan curah hujan ekstrem. Data yang digunakan, yaitu curah hujan bulanan dan harian CHIRPS, serta data reanalisis aerosol black carbon, organic carbon, dan sulfat MERRA-2 tahun 1990-2019. Terdapat 4 indeks curah hujan ekstrem yang digunakan dari ETCCDMI (Expert Team for Climate Change Detection Monitoring and Indices), yaitu RX5day (max 5-day precipitation amount), R95P (very wet days), R10mm (number of heavy precipitation days), dan CWD (consecutive wet days). Hasil penelitian menunjukkan distribusi korelasi signifikan antara aerosol dengan curah hujan dengan tingkat kepercayaan 80% terdapat di semua pulau di Indonesia dengan nilai korelasi maksimum 0,6 dan -0,6. Distribusi korelasi tertinggi terdapat di pulau Papua dan terendah di pulau Jawa, hal ini dikarenakan terdapat banyak faktor penyebab curah hujan. Tren tahunan curah hujan ekstrem dengan aerosol di Pulau Papua dan Pulau Jawa menunjukkan tren positif yaitu seiring bertambahnya tahun, nilai aerosol mengalami peningkatan yang diikuti peningkatan fluktuasi indeks curah hujan ekstrem yang menunjukkan kenaikan nilai aerosol menyebabkan kenaikan fluktuasi curah hujan ekstrem di kedua Pulau tersebut dengan nilai aerosol Pulau Jawa yang lebih tinggi dibandingkan Pulau Papua., Rainfall is one of the climate elements that is affected by climate change, such as changes in rainfall patterns, increased rainfall intensity, and increased frequency of extreme events. One of the factors causing rainfall is aerosols. Aerosols have an essential role in the global climate through two mechanisms, namely, direct and indirect. This study aims to analyze the spatial correlation and the effect of aerosol variations on rainfall in the Indonesian region from 1990-2019 and determine the annual trend of aerosols with extreme rainfall. The data used are CHIRPS monthly and daily rainfall, MERRA-2 black carbon, organic carbon, and sulfate aerosol reanalysis data for 1990-2019. There are four extreme rainfall indices used from ETCCDMI (Expert Team for Climate Change Detection Monitoring and Indices), namely RX5day (max 5-day precipitation amount), R95P (very wet days), R10mm (number of heavy precipitation days), and CWD (consecutive wet days). The results showed the distribution of a significant correlation between aerosols and rainfall, with a confidence level of 80% found in all Indonesian islands with a maximum correlation value of 0.6 and -0.6. The highest correlation distribution is on the island of Papua and the lowest is on the island of Java. This is because many factors cause rainfall. The annual trend of extreme rainfall with aerosols on the Papua and Java Islands shows a positive trend. That means as the years increased, the aerosol value increased, followed by an increase in extreme rainfall index fluctuations. This shows that an increase in aerosol value causes an increase in extreme rainfall fluctuations on the two islands, with a value of aerosols on
Keyword: Aerosol, extreme rainfall, Jawa island, Papua island, spatial  correlation

Judul: The Impact of Convective Available Potential  Energy (CAPE) on Spatio-Temporal Variations of Indonesian Extreme Rainfall
Abstrak: Distribusi curah hujan berkaitan erat dengan dinamika dan termodinamika atmosfer. Umumnya, kondisi stabilitas atmosfer dapat merepresentasi proses pembentukan curah hujan di permukaan. Convective Available Potential Energy (CAPE) merupakan salah satu parameter atmosfer yang dapat menjelaskan kondisi ketidakstabilan atmosfer. Fluktuasi peningkatan CAPE berpotensi pembentukan awan konvektif, sehingga mengakibatkan terbentuknya curah hujan ekstrem suatu wilayah. Tujuan dari penelitian ini adalah menjelaskan berbagai kondisi spasial dan temporal dari variasi Convective Available Potential Energy (CAPE) dan curah hujan ekstrem di Indonesia, serta menganalisis hubungan korelasi nilai CAPE terhadap curah hujan dan beberapa indeks curah hujan ekstrem di Indonesia. Cropping dan subsetting merupakan tahapan awal dalam ekstraksi data curah hujan APHRODITE dan CAPE dalam analisis kondisi wilayah Indonesia. Perhitungan indeks curah hujan ekstrem telah dikembangkan oleh Expert Team for Climate Change Detection Monitoring and Indices (ETCCDMI), diantaranya indeks R95p (very wet days), CDD (consecutive dry days), CWD (consecutive wet days), R10mm (heavy rain), R20mm (very heavy rain), dan SDII (simply daily intensity index). Tahun 1983 – 2007 secara umum, wilayah Indonesia mengalami trend kejadian ekstrem dengan kategori ekstrem kering yang terlihat pada indeks CDD yang meningkat secara signifikan (p-value < 0,05), terutama pada wilayah Papua, berdasarkan uji statistik Mann-Kendall. Kontribusi CAPE terhadap curah hujan di Indonesia signifikan terjadi saat musim MAM, dan SON, dan rendahnya nilai CAPE saat musim JJA berkorelasi positif signifikan terhadap kondisi curah hujan rendah pada periode tersebut. Sedangkan, besarnya nilai CAPE menyebabkan meningkatnya indeks CWD dan R10mm, dengan koefisien korelasi positif yang signifikan, sedangkan pada indeks CDD mengalami penurunan kejadian yang signifikan, dengan koefisien korelasi negatif., Precipitation distribution is closely related to atmospheric dynamics and thermodynamics. In most cases, instability atmospheres describe the process of precipitation formation on the surface. Convective Available Potential Energy (CAPE) is one measure that takes into account instability. An increase in the CAPE parameter has the potential to cause the convective cloud effect, which causes the region's extreme rainfall. The aim of this study is to better understand the spatial and temporal variations in conditions caused by varying convection energy or Convective Available Potential Energy (CAPE) and rainfall extreme events in Indonesia, as well as the relationship between CAPE value and some rainfall extremes index. Cropping and subsetting were carried out using rainfall data from APHRODITE and CAPE from ECMWF. Based on the Expert Team for Climate Change Detection Monitoring and Indices(ETCCDMI), rainfall data was converted into the extreme rainfall index R95p (very wet days), CDD (consecutive dry days), CWD (consecutive wet days), R10mm (heavy rain), R20mm (very heavy rain), and SDII (simply daily intensity index). According to Mann-Kendall statistics, Indonesia experienced an extreme trend from 1983 to 2007, with a higher extreme category reflected in a rising CDD index (p-value<0,05), particularly in Papua. In Indonesia, the CAPE contribution to rainfall is significant during the MAM and SON seasons, and a low CAPE value during the JJA season has a significant positive correlation with low rainfall conditions during that period. Meanwhile, with a p-value of <0,05, the magnitude of the CAPE value showed a significant positive correlation to the CWD and R10mm indices and a negative correlation to
Keyword: Atmospheric convection, ETCCDMI, rainfall extremes, spatio-temporal, trend

Judul: Construction of Strongly Optimal Binary Linear Code with Minimum Distance 9 and 11
Abstrak: A binary linear code of length n over q F is a subspace of n q F . A code has three parameters that attached to it, namely length, dimension, and minimum distance. A code with length n, dimension k and minimum distance d is often called [n, k, d ]-code. Usually, when two parameters are given, then we want to find a code that has the best value for the last parameter. Based on Gilbert- Varshamov bound, if a [n, k, d ]-code exists and can not be expanded, we call it a strongly optimal code. In this paper, we construct strongly optimal code with minimum distance 9 and 11. In constructing the code, we created a theorem and algorithm based on Gilbert-Varshamov bound before we implement the algorithm to MAPLE programming language. Because of computational limitations, the program can only construct up to k = 10 for d = 9 and k = 12 for d = 11.
Keyword: