Judul: Productivity and Profitability of Reticulate Loach Fish Farming in Multilevel Racking System with Different Aquarium Heights
Abstrak: Sistem rak bertingkat memanfaatkan ruang vertikal melalui penataan wadah yang disusun ke atas sehingga dapat meningkatkan volume produksi pada luasan lahan yang sama. Pemanfaatan ruang vertikal dapat dilakukan dengan cara mengurangi ketinggian wadah sehingga jumlah wadah dalam satu unit rak bertambah. Botia india (Botia lohachata) merupakan ikan hias yang bersifat demersal dan bottom feeder sehingga diharapkan dampak dari pengaturan tinggi wadah tidak memengaruhi kelangsungan hidup dan pertumbuhan ikan secara signifikan. Penelitian bertujuan menganalisis produktivitas dan profitabilitas usaha budidaya botia india pada sistem rak bertingkat dengan tinggi wadah yang berbeda. Penelitian dilakukan pada dua unit rak bertingkat dengan tinggi dan jumlah wadah per rak yang berbeda. Hasil penelitian menunjukkan bahwa rata-rata produktivitas rak sebesar 185.352±520 ekor tahun-1m-2 pada tinggi wadah 30 cm dan 248.689±544 ekor tahun-1m-2 pada tinggi wadah 20 cm. Kinerja usaha terbaik didapatkan pada perlakuan tinggi wadah 20 cm dengan nilai harga pokok produksi Rp1.283, rasio R/C 1,43, dan payback period 0,48 tahun., The multi-tiered rack system utilizes vertical space by arranging tanks stacked upwards, thus increasing production volume on fixed area of land. The use of vertical space can be done by reducing the height of the tank so the quantity of tanks in one rack unit increases. Reticulate loach (Botia lohachata) is a demersal and bottom feeder ornamental fish, so it is expected that the impact of tank height setting does not significantly affect fish survival and growth. The study aimed to analyze the productivity and profitability of reticulate loach cultivation in a multi-tiered rack system with different tank heights. The study was conducted on two multi-tiered rack units with different heights and quantity of tanks per rack. The results showed that the average rack productivity was 185,352±520 fish year-1m-2 at 30 cm tank height and 248,689±544 fish year-1m-2 at 20 cm tank height. The best business performance was obtained in the 20 cm tank height treatment with a cost of production Rp1,283, R/C ratio 1.43, and payback period 0.48 years.
Keyword: Productivity, Profitability, Reticulate Loach, Tank Height, Vertical System

Judul: Production Performance of Indian Botia (Botia lohachata) Size 1 Centimeter with Different Stock Density
Abstrak: Pembudidaya ikan botia india umumnya masih memelihara ikan dengan kepadatan rendah yang menyebabkan produktivitasnya kurang efisien. Upaya untuk meningkatkan produksi dapat dilakukan dengan meningkatkan kepadatan ikan. Penelitian ini bertujuan untuk mendapatkan produksi yang terbaik botia india (Botia lohachata) pada pendederan benih ukuran 1 cm melalui peningkatan padat tebar. Penelitian ini menggunakan rancangan acak lengkap (RAL) yang terdiri dari empat perlakuan padat tebar ikan dan tiga ulangan. Perlakuan padat tebar ikan tersebut yaitu: 2 ekor L-1 (A), 3 ekor L-1 (B), 4 ekor L-1 (C) dan 5 ekor L-1 (D). Selama penelitian ikan diberi pakan cacing sutra serta dilakukan pengelolaan kualitas air berupa penyiponan dan pergantian air. Hasil penelitian menunjukan bahwa perlakuan berpengaruh nyata terhadap semua parameter produksi, yakni tingkat kelangsungan hidup, laju pertumbuhan spesifik, laju pertumbuhan harian, pertumbuhan panjang mutlak dan efisiensi pakan. Produksi pendederan ikan botia india yang terbaik dicapai pada padat penebaran 4 ekor L-1., Indian botian fish farmers generally still maintain fish at a low density which causes their productivity to be less efficient. Efforts to increase production can be done by increasing fish density. This study aimed to obtain the best production of Indian botia (Botia lohachata) in 1 cm seed nurseries through increasing stocking density. This study used a completely randomized design (CRD) consisting of four fish stocking density treatments and three replications. The fish stocking density treatments were: 2 fish L-1 (A), 3 fish L-1 (B), 4 fish L-1 (C) and 5 fish L-1 (D). During the research, the fish were Tubifex sp. and water quality management was carried out in the form of siphoning and water change. The results showed that the treatment had a significant effect on all production parameters, namely survival rate, specific growth rate, daily growth rate, absolute length growth and feed efficiency. The best nursery production of Indian botia fish is achieved at the stocking density of 4 fish L-1.
Keyword: density, growth, indian botia, production

Judul: Analisis dan Implementasi Certificate Authorities (CA) pada Public Switched Telephone Network (PSTN)
Abstrak: Secure Telephone Protocol has ability to authenticate involved party and keep the secrecy of the message sent over the protocol. The secrecy of the message archieved by using symmetric key cryptographic scheme, and authentication archieved using public key cryptographic scheme. One of several party involved in the protocol and hold an important function called Certificate Authorities or CA. CA responsible for generating public key pair for other party involved in the protocol. When CA generates public key pair, several primitive cryptographic scheme used for guarantee the security of the key. Two of them are hash function SHA-1 and El-Gamal public key scheme embedded in Digital Signature Algorithm scheme. The prototype implementing the scheme above developed using Java programming language with JCE addition from Bauncy Castle. The analysis towards implemented prototype indicates that the prototype still has some flaws to be implemented in real world.
Keyword: