Judul: Pendugaan Kerapatan Populasi Hama Kutu Kebul (whitefly) pada Tanaman Sayuran Menggunakan Watershed Segmentation
Abstrak: Witheflies Bemisia tabaci and Trialeurodes vaporariorum are two important pests on vegetables. This research proposed a new method of estimating population density of whiteflies using watershed algorithm. Estimate of population density was obtained by counting the number of pests found on leaves. Watershed algorithm is highly appropriate for segmentation of whitefly, because this algorithm works properly on objects which has low gray level variation and overlapping areas. The research methodology consisted of image acquisition, image preprocess, image enhancement segmentation, calculation of whitely, calculation of infested leaf area, calculation of whitefly population density, and evaluation of infestation level estimates. Data used in this research were digital images of vegetable leaves infested by the whiteflies. Image pre-processing was used to reduce errors that might occur in the process of segmentation with watershed algorithm. Image enhancement with was aimed to reduce noises. Whitefly calculation was done after image segmentation. Infestation area was calculated by sampling leaf areas. The goal was to separate the non object areas so not to be included in the calculation process. The calculation results used to determine the level of pest population density. Whitefly densities were calculated using two methods: sampling area and leaf segmentation. The sampling area method was used when the observed images had a background difficult to separate from leaf objects, and the leaves were not in perfect condition such as folded, truncated, or blured. Whereas, the leaf segmentation method were used when the leaves images were in perfect condition, not bent or not blured, and the background was easy to separate. The process of testing was done using images grouped into three levels: low, moderate, and severe. Results of both methods then were with the estimates by expert. Our research showed that estimation of whitefly population density had an error of 12,5%. The sampling area method was chosen to estimate whitefly density because of its closeness to the expert estimates. Based on this method, the pest population infetations were grouped into three levels: low (≤ 10%), moderate (> 10% until ≤ 30%), and severe (> 30%). The system of estimating whitefly density developed through this research is expected to help pest observers in executing pest population monitoring.
Keyword: image processing, estimation of pest density, watershed segmentation

Judul: Segmentasi Citra Menggunakan Metode Segitiga untuk Pengukuran Tingkat Kerapatan Hama Kutu Kebul
Abstrak: Whitefly, Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae), is one of the major important pests of vegetables. Its small size and the insufficient number of pest observers have cause difficulties in monitoring the pests. One solution to overcome this problem is by using digital image processing. With digital image processing techniques, pest density can be measured accurately. In this study, triangle method is used to get the dynamic threshold value to be used in the segmentation process. The Images of vegetable used in this study are 23 images of eggplant leaves. The image will pass through several stages, including preprocessing, image segmentation and density calculations. The result of Image segmentation for 23 images using the triangle method has an accuracy of 75.36%. This suggests that the triangle method can be used for the segmentation process of whitefly pests in vegetable crops leaf image. By using this method, pest density calculation can be done optimally.
Keyword: Bemisia tabaci, triangle method, whitefly

Judul: Characterization of CoCrMo alloy with titanium nitride and hydroxyapatite-chitosan coating
Abstrak: Endoprosthetic is moving tool for implant in the body, made of metals or polymers. Stainless steel, Co-based alloys, and Ti materials are widely used for implant materials. Co alloy used is CoCrMo which has excellent properties such as good biocompatibility, corrosion resistant, good mechanical properties such as hardness, strength, and high wear resistance, supporting its utilization as an implant material. CoCrMo alloy was synthesized using tri arc furnace with heating temperature of 3000 °C. TiN coating using plasma sputtering and nitriding method, characterized by a layer of gold. The content of Ti in the layer was 3.85% (w/w), whereas the content N was difficult to determine. Hydroxyapatite (HAp) was synthesized using wet method with Ca source of chicken eggshell and P source of H3PO4 80%. HAp-chitosan composite coating aimed at improving the biocompatibility and corrosion resistance of CoCrMo. In vitro test showed that CoCrMo with TiN and HAp-chitosan coating had excellent corrosion resistance in liquid medium infusion, whereas samples HAp and CoCrMo with TiN coatings and HAp-chitosan had high level of toxicity in endothelial cell culture tests.
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