Fakultas Pertanian

Barometer ketahanan pangan dilihat dari 3 hal : Ketersediaan (Produksi), Aksesibilitas, dan Konsumsi terhadap pangan. Penelitian ini telah dilakukan di Kabupaten Lombok Barat, NTB yang menemukan masalah utama dalam mempertahankan konsumsi dan bagaimana masyarakat tahan terhadap pangan. Semoga bisa menjadi acuan untuk penelitian selanjutnya bagi para peneliti di bidang ketahanan pangan (food security).

Regards

We report epitaxial growth of a-plane (1120) AlInN layers nearly-lattice-matched to GaN. Unlike for c-plane oriented epilayers, a-plane Al1−xInxN cannot be simultaneously lattice-matched to GaN in both in-plane directions. We study the influence of temperature on indium incorporation and obtain nearly-lattice-matched Al0.81In0.19N at a growth temperature of 760 o C. We outline a procedure to check in-plane lattice mismatch using high resolution x-ray diffraction, and evaluate the strain and critical thickness. Polarization-resolved optical transmission measurements of the Al0.81In0.19N epilayer reveal a difference in bandgap of ∼140 meV between (electric field) E c [0001]-axis and E⊥c conditions with room-temperature photoluminescence peaked at 3.38 eV strongly polarized with E c, in good agreement with strain-dependent band-structure calculations.

We report a comparative study of the microstructure of a-plane ð1 1 2 0Þ InN epilayers grown on different buffer layers via metalorganic vapour phase epitaxy. Under optimized growth conditions, the crystalline quality of the InN epilayer is found to be best on an AlN buffer layer compared to that on GaN buffer layers or InN nucleation layers. All a-plane InN epilayers show an anisotropy in the in-plane mosaicity with the in-plane tilt value being different along the c-and m-directions. We also observe a Nagai-like tilt in all the epilayers. The magnitude and nature of this anisotropy and the Nagai-like tilt is also strongly influenced by the buffer layer. Our investigations show that InN grown on an AlN buffer has smaller in-plane tilt, basal plane stacking fault density, and background carrier concentration resulting in a higher mobility and a low band gap energy of $ 0:70 eV.

This paper proposed a method that combines Polar Fourier Transform, color moments, and vein features to retrieve leaf images based on a leaf image. The method is very useful to help people in recognizing foliage plants. Foliage plants are plants that have various colors and unique patterns in the leaf. Therefore, the colors and its patterns are information that should be counted on in the processing of plant identification. To compare the performance of retrieving system to other result, the experiments used Flavia dataset, which is very popular in recognizing plants. The result shows that the method gave better performance than PNN, SVM, and Fourier Transform. The method was also tested using foliage plants with various colors. The accuracy was 90.80% for 50 kinds of plants.

Shape is an important aspects in recognizing plants. Several approaches have been introduced to identify objects, including plants. Combination of geometric features such as aspect ratio, compactness, and dispersion, or moments such as moment invariants were usually used toidentify plants. In this research, a comparative experiment of 4 methods to identify plants using shape features was accomplished. Two approaches have never been used in plants identification yet, Zernike moments and Polar Fourier Transform (PFT), were incorporated. The experimental comparison was done on 52 kinds of plants with various shapes. The result, PFT gave best performance with 64% in accuracy and outperformed the other methods.

Omental pregnancy is the least common form of abdominal pregnancy. We present a rare case of primary omental pregnancy where patient presented with typical clinical feature of ectopic pregnancy. Trans-vaginal scan revealed an empty uterus with presence of adnexal mass. Fetal echo and fetal heart activity were seen within the mass. However, bilateral fallopian tubes and ovaries appeared to be normal. Part of the omentum was resected to remove a suspicious looking mass, which turned out to be an omental pregnancy.

Photoluminescence spectra from disordered InN were studied in very high magnetic fields. The samples had Gaussian spectra with low temperature emission peaks at 0.82 and 0.98eV, respectively. The average spatial extent of the excitonic wave functions, inferred from the diamagnetic shift, is only 2–3nm. This shows that the recombination is from an ensemble of highly localized states within a landscape of a smooth (classical) disorder potential of strength of the order of 10meV. The anomalies in the temperature dependence of the photoluminescence peak and linewidth give further support to the picture of trapped photoexcited carriers.

This paper reports the results of experiments in improving performance of leaf identification system using Principal Component Analysis (PCA). The system involved combination of features derived from shape, vein, color, and texture of leaf. PCA was incorporated to the identification system to convert the features into orthogonal features and then the results were inputted to the classifier that used Probabilistic Neural Network (PNN). This approach has been tested on two datasets, Foliage and Flavia, that contain various color leaves (foliage plants) and green leaves respectively. The results showed that PCA can increase the accuracy of the leaf identification system on both datasets.

One of important components in an image retrieval system is selecting a distance measure to compute rank between two objects. In this paper, several distance measures were researched to implement a foliage plant retrieval system. Sixty kinds of foliage plants with various leaf color and shape were used to test the performance of 7 different kinds of distance measures: city block distance, Euclidean distance, Canberra distance, Bray-Curtis distance,  2 statistics, Jensen Shannon divergence and Kullback Leibler divergence. The results show that city block and Euclidean distance measures gave the best performance among the others.