Judul: Penggunaan Persamaan Eksponensial Negatif dan Model Regresi Berganda dalam Membuat Model Struktur Tegakan Hutan Tidak Seumur
Abstrak: Model struktur tegakan dapat digunakan dalam pendugaan dimensi tegakan yang meliputi kerapatan pohon tegakan, luas bidang dasar tegakan dan volume tegakan. Untuk dapat menggunakan struktur tegakan dalam pendugaan dimensi tegakan perlu ditunjang oleh ketelitian hasil yang dicapai dan ketidakpastian dalam penggunaannya. Penelitian ini bertujuan untuk mengetahui besarnya ketelitian hasil pendugaan dimensi tegakan dengan menggunakan model hubungan struktur tegakan.
Keyword: 

Judul: Model Penduga Volume Tegakan menggunakan Citra Resolusi Tinggi di Hutan Pendidikan Gunung Walat.
Abstrak: Hutan Pendidikan Gunung Walat (HPGW) merupakan hutan tanaman yang didominasi beberapa tegakan seperti agathis, pinus, dan puspa. Data pendugaan volume tegakan yang akurat dapat diperoleh dengan pengukuran terestris, namun metode tersebut memerlukan waktu yang lama dan mahal. Teknologi penginderaan jarak jauh dapat dijadikan alternatif untuk mengatasi keterbatasan dari metode terestris. Penelitian ini bertujuan membangun model penduga potensi volume tegakan berbasis piksel dan berbasis visual dengan menggunakan citra resolusi tinggi. Hasil analisis berbasis piksel dan visual dengan menggabungkan semua stratum memiliki model regresi tidak nyata karena p-value ˃ α (α=5%). Penghapusan outlier untuk model regresi memiliki R2 yang rendah. Maka perlu dilakukan restratifikasi stratum per jenis tegakan. Hasil dari restratifikasi stratum terdapat 3 jenis tegakan yang akan dibuat model persamaan regresi, yaitu tegakan konifer, daun lebar, dan campuran (agathis-puspa). Pemilihan model terbaik didasarkan dari p-value, R2, dan nilai PRESS. Model berbasis piksel yang terpilih untuk tegakan konifer yaitu V= 47.5e7.02 GNDVI yang mempunyai nilai R2 sebesar 54.20% dan untuk tegakan daun lebar yaitu V= 3866.09GNDVI 2.85 dengan nilai R2 sebesar 53.40%. Model berbasis visual yang terpilih untuk tegakan konifer yaitu V= 1274.1CC3.38 dengan nilai R2 sebesar 61% dan tegakan daun lebar yaitu V= 26.959 e5.54CC dengan nilai R2 sebesar 60.60%. Model tegakan daun campuran tidak memiliki model regresi karena p-value ˃ α (α=5%).
Keyword: Model Regresi, Penginderaan Jarak Jauh, Volume Tegakan

Judul: Effectiveness of Microwave Oven against B. cereus to Reach Food Safety Objective in Cook-chill Foods
Abstrak: Cook-chill foods are meal that being cooked and then chilled quickly until further consumption. Usually before being consumed, the foods are reheated by the consumers to improve the organoleptic property and also to destroy bacteria. One of the things that need to be considered is that cook-chill foods that are originated from grains like rice or wheat are vulnerable to be contaminated by pathogen, especially Bacillus cereus. Another problem is that on the packaging of specific cook-chill food that being investigated, there is only instruction manual on how to reheat the food with 1800 W microwave oven. Microwave oven that is being used in household level is usually lower than 1000 W, so there is a possibility under-cooking may happen because there is no standardization on how to heat food with microwave on household level. The research was conducted in five steps, which were; (1) investigation of standard plate count and B. cereus count on two cook-chill foods (spaghetti bolognaise and black pepper chicken rice), (2) challenge test on those cook-chill foods to evaluate the growth of B. cereus on cook-chill food on 15oC, (3) challenge test to evaluate inactivation of vegetative cells and spores of B. cereus by microwave oven (850 watt and 410 watt), (4) to evaluate if FSO of those cook-chill foods could be achieved based on data gathered in the previous results, and (5) to study the effect of microwave oven and moist heat against leakages of nucleic acids and proteins of B. cereus. The results of this research were that microwave oven with 850 watt power could still reach food safety objective (FSO) when cook-chill foods were being reheated for the recommended time on the packagings (45 seconds for spaghetti bolognaise and 2 minutes for black pepper chicken rice), however when using 410 watt microwave oven, FSO could not be achieved. The mechanism of which why microwave oven could destroy vegetative cell and spores of B. cereus was also investigated. The result was that heat treatment using microwave oven differed when compared to moist heat since heat treatment using microwave oven caused leakages of nucleic acid and protein content of the vegetative cells and spores of B. cereusin much larger effect than moist heat.
Keyword: cook-chill foods, Bacillus cereus, microwave, rice, spaghetti, food safety objective