Vol. 30 No. 2 (1998)

Tiga senyawa turunan flavan-3-ol, yakni afzelekin-3-O-a-L-ramnosida (1), katekin (2), dan afzelekin (3), telah ditemukan pada kulit batang dan kulit akar tumbuhan Artocarpus reticulatus Miq. (Moraceae), suatu tumbuhan langka yang berasal dari Sulawesi dan endemik untuk Indonesia, serta dikenal dengan nama daerah maumbi. Struktur molekul ketiga senyawa tersebut telah ditetapkan berdasarkan data fisika dan spektroskopi. Three Flavan-3-ols from Artocarpus reticulatesThree flavan-3-ol derivatives, namely afzelechin-3-O-α-L-rhamnoside (1), catechin (2) and afzelechin (3), were isolated from the…

Algoritma pengendalian aliran yang bersifat adaptif dapat diterapkan pada jaringan ATM wilayah luas guna mengalokasikan kebutuhan lebar pita pada hubungan virtual. Pengendalian aliaran menggunakan mekanisme control lup tertutup, yaitu suatu mekanisme kontrol yang bersifat reaktif dan secara dinamis, mengatur kecepatan transmisi sel yang diizinkan untuk setiap hubungan virtual dengan menggunakan informasi umpan balik dari jaringan. Informasi umpan balik berupa bit yang dapat mengidentifikasi apakah panjang antrian di buffer berada di atas atau di bawah batas ambang yang diberikan. Dengan bit…

In this paper, a new approach to analysis of the average and rms currents in inverter switching devices and the rms value of the ripple component of inverter input current is presented. The proposed approach is based on the probability with which the inverter switching devices receive ON signals which can be obtained from the average value of the phase-to-dc midpoint voltages. As the knowledge of the exact switching pattern is not required, this approach is especially useful for inverters in which the exact switching patterns can not be predetermined. To show the general applicability of the…

Airborne video images which have several advantages over satellite images and aerial photographs were captured over some selected areas. After they were refined to increase their interpretability, the images were assessed in accordance with the existing map accuracy specifications. Four algorithms of image refinement were tested. These include projective, row duplication, row interpolation and statistical correlation function. Numerous test points were selected on the image and their coordinates were compared to their ground positions. The results suggest that a solid-state video camera can…