Judul: Optimasi Portofolio Obligasi Yang Terimunisasi Dengan Goal Programming, Optimization of immunized bond portfolios using goal programming
Abstrak: In a term investments, portfolio is defined as a collection of securities, i.e. real or financial assets. Portfolio can bo arranged in a form of bonds of stocks. Bonds are considered as types of securities that have smaller risk than stocks. Based on the type, the bond are devided into goverment and corporate bonds. The risk of bonds is obtained from the risk of interest rate swing, maturity, and default risk that exist on each bond. Those risks affect the rate of return equal to or grater than the purchase price of the bonds. Therefore, the concept of immunization is introduce to reduce the level of riskc in the portfolio composed by various types of bonds. In the immunized bond portfolio the risk that exist on the bonds will be minimized so that the rate of return obtained by investors in the future will be maxmized. The implementation of optimizing the immunized bond portfolios is carried out using goal programming with LINGO 11.0. The result of this optimizztion id the proportion of immunized bond portfolios which gives maximal return and minimal risk over a particular investment period.
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Judul: Comparison of the Level of Effectiveness of Duration Strategies in Immunization of Corporate Bond
Abstrak: Imunisasi merupakan suatu strategi yang digunakan oleh investor dalam rangka melindungi obligasi dari risiko tingkat suku bunga dengan cara menyamakan durasi portofolio dengan holding period yang diharapkan oleh investor. Konsep durasi menjadi kunci dalam melakukan imunisasi. Durasi Macaulay dan durasi yang dimodifikasi merupakan konsep durasi yang paling sering digunakan. Karya ilmiah ini membahas bagaimana perubahan tingkat suku bunga akan memengaruhi obligasi serta mengilustrasikan bahwa konsep durasi Macaulay dan durasi yang dimodifikasi dapat mengimunisasi portofolio obligasi dari risiko tingkat suku bunga. Aset obligasi yang diteliti adalah obligasi korporasi yang diterbitkan pada tahun 2018, dan perubahan tingkat suku bunga yang digunakan adalah penurunan tingkat suku bunga yang terjadi pada bulan Juli 2019. Berdasarkan hasil penghitungan, perubahan tingkat suku bunga memiliki hubungan yang berbanding terbalik dengan harga obligasi, serta strategi durasi yang dimodifikasi memiliki hasil yang lebih efektif dalam mengimunisasi portofolio obligasi korporasi dari risiko tingkat suku bunga dibandingkan dengan durasi Macaulay., Immunization is a strategy used by investors in order to protect bonds from the risk of fluctuating by equating the duration with the holding period expected by investors. The concept of duration is vital in immunization. Macaulay’s duration and modified duration are the most commonly used duration concepts. This thesis discusses how changes in interest rates will affect bonds and illustrates that the concepts of Macaulay’s duration and modified duration can immunize a bond from interest rate risk. The bond assets studied are corporate bonds issued in 2018, and the changes in interest rates used are interest rate reductions that occurred in July 2019. Based on the calculation results, changes in interest rates have an inversely proportional relationship with bond price, and modified duration strategy has a more effective result in immunizing corporate bond from interest rate risk compared to Macaulay’s duration.
Keyword: bond corporation, immunization, interest rate risk, Macaulay's duration, modified duration

Judul: Bioecology of Earthworm Pheretima darnleiensis
Abstrak: Pheretima darnleiensis is a native earthworm in Southeast Asia, India, Japan, and Indonesia, however there is lack of study on P. darnleiensis. Determining the characteristics of P. darnleiensis and the ecology surrounding its habitat is needed in order to culture the earthworm. Hence, this study was aimed to study the structure of several organs and morphological characters that can be used to identify P. darnleiensis and its habitat condition. Earthworms were collected in a plot of 100 x 100 x 20 cm in 10 locations and were identified. The structure of P. darnleiensis organs was studied histologically using paraffin. Pheretima darnleiensis did not have diverticula and stalked gland on copulatory pouches, nephridia occurred on bithecate spermatheca, and the first spermathecal pores were at segment 4/5. Based on this study, the highest population of P. darnleiensis was found in an area containing abundance of other earthworm species at 15 individuals/m2, plant cover at 25.00%, soil arthropods at 16.32 individuals/kg fresh soil, abiotic component cover at 78.50%, soil temperature at 27.42 ± 1.01 oC, soil pH at 5.77 ± 0.53, soil moisture at 19.83 ± 9.92%, organic carbon at 3.39%, N at 0.29%, P at 286.80 ppm, K at 500.00 ppm, sand at 28.76%, silt at 38.74%, and clay at 32.50%. Silt fraction could be considered as one of factors influencing P. darnleiensis abundance.
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