On Improving the Students’ Combinatorial Thinking Skill in Solving Rainbow Antimagic Colouring Problem on Cryptography for E-Commerce Security Systems under the Implementation of Research-Based Learning with STEM Approach

Combinatorial thinking is the process of obtaining multiple solutions for discrete problem-solving. Combinatorial thinking skills have several indicators: identifying several cases, recognizing patterns from all cases, generalizing all cases, proving mathematically, and considering other combinatorial problems. The learning approach in schools is growing along with the development of science and technology, one of the approaches used in STEM. STEM education focuses students on solving problems in everyday life with the help of science, technology, engineering, and mathematics. This paper aimed to analyze the students’ combinatorial thinking skills after using a research-based learning worksheet with a STEM approach to solving the rainbow antimagic colouring problem. This study uses a mixed-method where this research combines qualitative and quantitative methods. The subjects of this research are undergraduate students of Mathematics Education, University of Jember. This study involved two classes, namely the experimental and control classes, where the researcher gave the two classes different treatments. The t-test compares students’ combinatorial thinking skills between the experiment and control classes after using research-based learning tools with a STEM approach for solving the rainbow antimagic problem. The homogeneity test results on the pre-test items indicated a significance value of .789 > .05, which indicates that the two classes are homogenous. The independent sample t-test score is .020 < .05, which means the difference is significant. It concludes that implementation of the research-based learning materials with a STEM approach can improve the students’ combinatorial thinking skills in solving the rainbow antimagic colouring

Comparison of Online and Offline Learning During The COVID-19 Pandemic using Naïve Bayes Method and C4.5

Learning is a process of interaction between educators and students who meet the elements of learning carried out in an educational environment, so that learning can develop student’s abilities, interests and talents optimally. In today's era learning is done online and inversely with offline. The purpose of this study is to analyze the comparison of percentages and classification results as well as the results of learning evaluations using the Naïve Bayes method and C4.5. This test is carried out with 4 variables and a comparison of the two methods. The results showed that the accuracy of Naïve Bayes was 74.07% and C4.5. of 77.77% so that the comparison results show that the level of accuracy of the C4.5 method is better than Naïve Bayes. The resulting importance variables are time and effectiveness as well as the results of the classification of learning decisions, namely the offline category as many as 16 data on the Naïve Bayes method and 19 data on the Decision Tree algorithm C4.5 method from 27 input testing data

EVALUASI KINERJA JARINGAN IRIGASI PADA DAERAH IRIGASI TUNGKUB KECAMATAN MENGWI, KABUPATEN BADUNG

Daerah Irigasi Tungkub (DI Tungkub) yang berada di Badung merupakan daerah irigasi teknis dengan sumber air dari Bendung Tungkub, Daerah Aliran Sungai Sungi (DAS Sungi). DI Tungkub memiliki luas rencana 1.092ha dan luas fungsional 1.045ha sumber. Saat ini di Subak Tungkub Dalem dan Tungkub Lanyahan yang berada di sawah paling hilir masih mengalami kekurangan air. Saat ini pada DI Tungkub sebagian saluran sudah rusak dan sebagian tanpa pasangan batu. Agar komitmen petani mempertahankan ekosistem sawah tetap eksis, maka perlu dilakuan evaluasi kinerja jaringan irigasi DI Tungkub sebagai tindak lanjut dari pengelolaan Jaringan Irigasi Tungkub. Hasil evaluasi ini diharapkan dapat diambil langkah-langkah atau tindakan-tindakan dalam memanfaatkan  air irigasi pada DI Tungkub sehingga efektif dan efisien. Penelitian ini dilakukan dengan tahapan analisis ketersediaan air, analisis kebutuhan air, analisis water balance, analisis efisiensi penyaluran irigasi, analisis efektifitas irigasi. Data yang disiapkan yaitu dimensi saluran, debit pengaliran, curah hujan dan pola tanam. Penelitian ini mendapatkan DI Tungkub pada Masa Tanam 2019 kekurangan (defisit) air pada pada Bulan Nopember-Desember 2018 dan Bulan Juli–Oktober 2019 dengan defisit tertinggi pada Bulan September 2019 sebesar 1.215,56lt/dt. Kelebihan (surplus) air terjadi Bulan Januari-Juli 2019 dengan surplus tertinggi terjadi pada Bulan Maret 2019, sebesar 1.620,01lt/dt. Nilai efisiensi pengaliran sebesar 87,46% menunjukkan saluran primer  pada DI Tungkub memiliki nilai efiesiensi pengaliran dibawah standar saluran perimer yang disyaratkan sebesar 90%, sehingga perlu dilakukan peningkatan atau perbaikan saluran eksisting dari BT.1 sampai BL.1. Nilai Efektifitas irigasi sebesar 95,69% menunjukkan saluran primer  pada DI Tungkub termasuk kriteria masih efektif

Characteristics and performance analysis of activated carbons derived from different precursors and activators for waste water adsorption

Domestic waste such as methylene blue from the dyeing process and detergent from laundry activities are sources of water pollution. Before being dumped into the water, this waste must be minimized. One approach that can be utilized is the adsorption method with activated carbon. To generate activated carbon with the properties required for this purpose, an appropriate precursor and manufacturing conditions must be chosen. The objective of this research is to investigate the characteristics and performance of activated carbon derived from various precursors (Petung and Santong bamboos) and activators (Ar, N2, and CO2) for detergent and methylene blue dye adsorption. The difficulty to be solved is determining the best precursor and activator for maximum methyl blue and detergent adsorption. Characterizations included FTIR, XRD, SEM, TGA, and adsorption isotherm testing. The study's findings show that activated carbons have functional groups O-H (hydroxyl), C-H (aldehydes and alkenes), C=C aromatic rings, C-H aromatic groups, and an amorphous structure. The presence of a porous and amorphous structure, as well as the C=C aromatic ring, makes activated carbons capable of absorbing methyl blue and detergent. Santong bamboo-activated carbon activated with argon has the best characteristics and adsorption capability. This activated carbon has a fixed carbon content of 76.34 %, pore volumes of 0.362 cc/g, average pore widths of 1.967 nm, pore surface area of 291.487 m2/g, bimodal pore size distribution, and methylene blue and detergent adsorption capabilities of 19.733 cc/g and 1.689 cc/g, respectively. The results obtained are on a laboratory scale, which necessitates additional research, particularly on how to create reservoirs and regenerate activated carbon simply and affordabl

Characteristics and performance analysis of different grain sizes bamboo-activated carbons for motorcycle flue gas adsorption

The use of fossil fuels in human activities such as motorcycles has led to an increase in the concentration emitted in the atmosphere. Various efforts and methods such as adsorption using activated carbon have been developed and applied to reduce the emission. Therefore, this study focuses on the characteristics and performance of bamboo-activated carbons in the adsorption of motorcycle flue gases. This was carried out using different grain sizes (z) of activated carbons AC-M1, AC-M2, and AC-M3 for grain sizes of z≤250, 250<z≤420, and 420<z≤590 microns, respectively, which were derived from swat bamboo and carbonized at a temperature of 750 ○C. Furthermore, physical activation was applied by heating the charcoal at the same temperature under a nitrogen flow rate of 150 mL/min nitrogen. The Thermogravimetric (TGA), scanning electron microscopy (SEM), and adsorption isotherm tests were employed for the characterization of activated carbons. Additionally, the performances of activated carbons for motorcycle flue gas adsorption (CO2, CO, and HC) were carried out by a motorcycle emission test. According to the results, activated carbon AC-M1 produced the best characteristics and performance for adsorption of motorcycle flue gas, as it has a pore volume of 0.135 cm3/g, a specific surface area of 244.69 m2/g, and a nitrogen adsorption capacity of 87.047 cm3/g. These characteristics prove to have good adsorption efficiencies at 100 %, 87.30 %, and 100 % for adsorption of CO2, CO, and HC, respectively

A NEW SPECIES OF BEGONIA (BEGONIACEAE) FROM MANUSELA NATIONAL PARK, SERAM

ARDHAKA, I. M., ARDI, W. H., UNDAHARTA, N. K. E. & TIRTA, I. G. 2016. A new species Begonia from Manusela National Park, Seram. Reinwardtia 15(1): 61 – 64. — A new species of Begonia, B. manuselaensis Ardhaka & Ardi, is described from Seram, Maluku province, Indonesia. The species is endemic to Seram and belongs to Begonia section Petermannia

ANALISIS REGRESI KELAS LATEN UNTUK DATA KATEGORIK DENGAN SATU KOVARIAT

Analisis regresi kelas laten merupakan analisis multivariat untuk data kategorik. Estimasi parameter pada analisis regresi kelas laten menggunakan algoritma EM (ekspektasi-maksimisasi) yang dilanjutkan dengan metode Newton-Raphson. Dalam penelitian ini, analisis regresi kelas laten digunakan untuk mengklasifikasikan responden berdasarkan persepsinya terhadap peluang (opportunity) dan ancaman (treath) bagi distributor produk Unilever, PT. Panahmas Dwitama Distrindo Regional Jember. Lamanya responden berlangganan terhadap distributor ini dijadikan sebagai kovariat. Hasil analisis menunjukkan bahwa berdasarkan persepsinya terhadap opportunity, responden dikelompokkan menjadi tiga kelompok, sedangkan terhadap treath dikelompokkan menjadi dua kelompok