Judul: Optimal Portfolio Formation with Passive and Active Strategies during Pre, Period, and Post Covid-19 Pandemic
Abstrak: Munculnya Pandemi Covid-19 menyebabkan peningkatan inefisiensi dan risiko pasar saham. Untuk mengurangi risiko, dilakukan diversifikasi dengan membentuk portofolio. Dikarenakan investor tidak boleh berinvestasi pada satu sektor saham saja, pembentukan portofolio pada penelitian ini dilakukan pada perwakilan sebelas sektor saham IDX-IC di BEI. Penelitian ini dilaksanakan pada April hingga Juli 2024 menggunakan metode Markowitz dengan strategi pasif dan aktif. Hasil penelitian ini menunjukkan bahwa Pandemi Covid-19 menyebabkan terjadinya penurunan return dan peningkatan risiko portofolio. Ditinjau dari segi komposisi saham, pada periode pra pandemi, sektor yang mencatatkan komposisi terbesar adalah sektor Barang Konsumen Primer, kemudian pada periode masa pandemi yaitu sektor Perindustrian dan Barang Konsumen Non-Primer, dan pada periode pasca pandemi yaitu sektor Keuangan. Strategi optimal pembentukan portofolio jika ingin meminimalkan risiko adalah strategi pasif, sementara jika ingin memaksimalkan return adalah strategi aktif., The emergence of the Covid-19 Pandemic has led to an increase in stock market inefficiency and risk. To decrease the risk, diversification is conducted by forming a portfolio. Due to the investor should not invest in only one stock sector, portfolio formation in this research was conducted on representatives of eleven IDX-IC stock sectors on the IDX. This research was conducted from April to July 2024 using the Markowitz method with passive and active strategies. The results of this research show that the Covid-19 Pandemic causes a decrease in return and an increase in portfolio risk. In terms of stock composition, in the pre-pandemic period, the sector that has the largest composition is the Primary Consumer Goods sector, while in the pandemic period is the Industry and Non-Primary Consumer Goods sectors, and in the post-pandemic period is the Financial sector. The optimal strategy for portfolio formation if you want to minimize risk is a passive strategy, while if you want to maximize returns is an active strategy.
Keyword: Markowitz Method, Optimal Portfolio, Stock, Passive & Active Strategy

Judul: Analysis of Optimal Stock Portfolio Formation during the Covid-19 pandemic with Multi-Index Models
Abstrak: Covid-19 berdampak ke sistem perekonomian, salah satunya dalam investasi saham. Risiko dalam investasi dapat diperkecil dengan membentuk portofolio. Karya ilmiah ini bertujuan mencari portofolio optimal dengan menggunakan model Multi Indeks. Model Multi Indeks menggunakan lebih dari satu indeks untuk menghitung expected return, sehingga dimungkinkan lebih akurat. Saham yang digunakan adalah saham yang tergabung di indeks LQ45 periode 1 Maret 2020 sampai 1 April 2021. Indeks pasar yang digunakan adalah IHSG, sedangkan indeks non-pasar adalah Dow Jones Industrial Average dan Hang Seng. Berdasarkan hasil penghitungan, portofolio optimal dibentuk dari 96.196498% saham TOWR dan 3.803502% ACES memiliki expected return harian sebesar 0.09047297% dengan risiko sebesar 2.52761%., Covid-19 has effect on the economic system, one of which is stock investment. The risk in investing can be minimized by forming a portfolio. The aim of this study is to determine the optimal portfolio using the Multi Index model. The Multi Index Model uses more than one index to calculate the expected return, so it is possible to be more accurate. The stocks used are stocks that are members of the LQ45 index for the period March 1, 2020 to April 11, 2021. The market index used is the IHSG, while the non-market indexes are the Dow Jones Industrial Avarage and the Hang Seng. Based on the calculation results, the optimal portfolio is formed from 96.196498% of TOWR stocks and 3.803502% of ACES which has an estimated daily return of 0.09047297% with a risk of 2.52761%.
Keyword: Covid-19, multi index model, portfolio

Judul: Design of gathering-conveying unit of mobile sugar cane trash chopping machine
Abstrak: A machine for gathering and chopping the piles of sugarcane trash on the field after harvesting is being designed. As a part of the machine, a gathering-conveying unit was designed. Important data including condition and characteristics of trash were collected and used for designing the unit. The average bulk density of trash on the field was 7.7 kg/m3, the average pressure to compress the trash from 40 cm to 30 cm thickness was 50.65 N/m2, and the pressure to compress the trash from 27 cm to 8 cm thickness was 1166.60 N/m2. The unit was designed to be operated at 0.3 m/s forward speed, and having 60 cm working width. The unit was consisted of: a gathering reel, a pair of conveyors, cover-frame and power transmission components. Size and operational speed of moving components were determined by analyzing mass flow rate of the trash, and operating power of the components. The gathering reel was 100 cm in diameter and having 4 series of gathering fingers for drawing and feeding the trash into the conveyors. A pair of chain-conveyors equipped with L-shaped steel bars was set face to face on lower side and upper side for conveying and feeding the leaves to the chopping unit. The stationary test showed that the gathering reel and the conveyors could work properly. The average rotational speed of the conveyor shaft and the gathering reel were 34.03 rpm and 9.97 rpm, respectively. The working capacity of the unit was 400-500 kg/hour.
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