Judul: Efficient Frontier Method for the Analysis  of Return on Stock Portfolio Risk in Several Sectors
Abstrak: Pasar modal memiliki pengaruh penting dalam perekonomian di Indonesia. Minat masyarakat untuk berinvestasi semakin meningkat didukung dengan kemudahan akses dalam berinvestasi. Instrumen investasi yang memiliki kapitalisasi paling besar ialah saham. Saham diklasifikasikan menurut sektor industri. Perlu dilakukan analisis portofolio saham sektor agar bisa diketahui potensi imbal hasil dan risiko dari portofolio saham sektor. Data yang digunakan untuk portofolio saham sektor terdiri dari saham sektor pertambangan (ADRO), saham sektor aneka industri (ASII), saham sektor properti (PWON), dan saham sektor keuangan (BMRI) dengan periode 1 Januari 2015 – 31 Desember 2019. Dilakukan pemodelan ARMA-GARCH untuk menghilangkan efek autokorelasi pada data dan heteroskedastisitas pada galat. Setelah itu dilakukan pemodelan copula untuk membentuk fungsi sebaran bersama galat baku. Selanjutnya dibuat grafik efficient frontier dari kedua portofolio dan dianalisis dengan asumsi imbal hasil maksimum, risiko minimum, dan reward-to-variability ratio maksimum. Hasil analisis tersebut menunjukkan portofolio aset berisiko saham sektor dapat disusun dengan 3 kemungkinan kriteria disesuaikan dengan preferensi dari investor menurut tingkat toleransinya terhadap risiko. Portofolio aset berisiko saham sektor dikombinasikan dengan aset bebas risiko membentuk portofolio lengkap., The capital market has an important impact on the economy in Indonesia. Public interest in investing is increasing supported by easy access to investing. The investment instrument that has the largest capitalization is shares. Shares classified according to industrial sectors. It is necessary to analyze sectoral stock to know potential yield risks from them. The data used for the sectoral stock portfolio consists of mining sector shares (ADRO), miscellaneous industry sector shares (ASII), property sector shares (PWON), and financial sector shares (BMRI) for the period January 1st 2015 - December 31st 2019. ARMA-GARCH modeling was carried out to eliminate the effects of autocorrelation on data and heteroscedasticity on errors. After that, copula modeling was carried out to form a distribution function with standard errors. Furthermore, efficient frontier graphs of the portfolio were made and analyzed with the assumption of maximum return, minimum risk, and maximum reward-to-variability ratio. The results of the analysis show that sectoral stock portfolios can be arranged with three possible criteria that are adjusted to the preferences of investors according to their level of rsik tolerance. Sectoral stock portfolios can be combined with risk-free asset to form a complete portfolio.
Keyword: efficient frontier, return, risk, sectoral stocks

Judul: Analysis of Returns and Risks of Sharia Stocks Portfolio and Conventional Stocks Portofolio with the Efficient Frontier Method
Abstrak: Kondisi pandemi di Indonesia, yang menjadi salah satu penyebab jumlah investor saham naik signifikan, membuat saham syariah semakin diminati. Kenaikan jumlah peminat tersebut harus dibarengi dengan kenaikan angka literasi saham syariah agar umat islam di Indonesia bisa berinvestasi dan tetap menjalankan aturannya sebagai seorang muslim. Perlu dilakukan analisis portofolio saham syariah dan konvensional agar bisa diketahui potensi dari kedua portofolio saham. Data yang digunakan untuk portofolio saham syariah adalah data saham Telkom dan Unilever, sedangkan untuk portofolio saham konvensional adalah data saham BCA dan BRI periode 1 Januari 2012-31 Desember 2018. Dilakukan pemodelan ARMA-GARCH untuk menghilangkan efek autokorelasi dan heteroskedastisitas pada galat. Setelah itu dilakukan pemodelan Copula untuk membentuk fungsi sebaran bersama galat baku. Selanjutnya dibuat grafik efficient frontier dari kedua portofolio dan dianalisis dengan asumsi risiko minimum, imbal hasil maksimum, dan reward-to-variability ratio maksimum. Hasil analisis tersebut menunjukkan portofolio saham syariah relatif lebih cocok dipilih bagi investor moderat, sedangkan portofolio saham konvensional relatif lebih cocok dipilih bagi investor agresif., Pandemic conditions in Indonesia, which one of the causes the number of stock investors increase significantly, the sharia stock becomes more interesting. The increase in the number of enthusiasts must be accompanied by an increase in the literacy rate of the sharia stock so that Muslims in Indonesia can invest and continue to carry out their rules as a muslim. It is necessary to analyze the returns and risks of sharia and conventional stock portfolio so that the potential of these two stocks portfolio can be seen. The data used for sharia stocks portfolio are Telkom and Unilever, whereas the data used for conventional stocks portfolio are BCA and BRI for the period 1 January 2012-31 December 2018. ARMA-GARCH modeling was carried out to eliminate the effects of autocorrelation and heteroscedasticity on the errors. After that, Copula modeling was carried out to form a joint cumulative distribution function of standard errors. Next, an efficient frontier graphs were made of those portfolios and analyzed with the assumption of minimum risk, maximum return, and maximum reward-to-variability ratio. The results of the analysis show that the sharia stock portfolio is relatively more suitable for moderate investors, while the conventional stock portfolio is relatively more suitable aggresive investors.
Keyword: return, risk, sharia stock, conventional stock, efficient frontier

Judul: Hydrothermal Synthesis of Biphasic Calcium Posphate
Abstrak: Biphasio calsium phosphate (BCP), which was a mixture of hydroxypatite (HA) and tricalcium phosphate (TCP), was synthesized by hydrothermal method followed by sintering process. Hydroxyapatite was produced by using natural calcium source CaO from hen's eggshell and (NH4)2HPO4 as phosphate souce, other hydroxyapatite sample was produce by using synthetic calcium source Ca(OH) and H3PO4 as phosphate source.
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