Judul: Image Searching Using Heuristic Method for Image Retrieval System.
Abstrak: The development of image retrieval system and user demand for a fast and accurate search engine motivates research on finding efficient retrieval methods. Commonly, image searching process works through computing and comparing similarity value between input query and entire database images. This process is not efficient due to time-wasting during computation especially for large database. This research proposes heuristic method for image searching. The basic idea of this research deals with structural database content that reduces searching time. This research implements fitness landscape model. Fitness landscape is kind of directed graph whose labeled vertices and edges. Each node represents an image and each edge represents distance or similarity value of a node to other connected nodes. Similarity value between nodes are computed using combination of three image features, those are color, shape, and texture. Heuristic algorithm moves on these nodes with Breadth-First Search mechanism under certain constraints. Each visited node that fulfills the requirement will be retrieved as searching result. This retrieval result is then evaluated using recall precision parameter to get value of searching effectiveness. This experiment also computes retrieval time for each query. As the result, heuristic method obtains average retrieval time up to nine times faster compared with the non-heuristic one. Hence, this proposed method is promising to be used in image retrieval system because it provides fast image searching. Keywords: image searching, fitness landscape, heuristic, content based image retrieval.
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Judul: Feature Extraction Based on Color, Shape and Texture for Animal Image Retrieval.
Abstrak: The differences in color, shape, and texture characteristics between each animal cause difficulties in animal image retrieval. Therefore, specified technique is needed to obtain pattern from each animal’s feature so that image retrieval might works properly. One of the techniques to obtain the pattern done by feature extraction. This research tries to develop image extraction method in Content Based Image Retrieval approach by using three image visual features (color, shape, texture). In this research, Fuzzy Color Histogram (FCH) for color feature extraction is used through computing the membership function using Cauchy function. In FCH, one color may belong to two bins histogram or more with different membership functions. Then, shape feature is extracted using edge direction histogram, where each image is processed using Sobel edge detection, and then the direction is mapped into a defined bin histogram. For texture feature extraction, the process uses co-occurrence matrix with computing the values of energy, moment, entropy, maximum probability, contrast, correlation and homogeneity. Similarity value between image query and images in database is computed based on its features, those are color, shape, texture, and its combination. Recall and precision value resulted in this research shows the largest average precision value is obtained from searching process using index combination (color, shape, texture) of feature extraction. Keywords: feature extraction, Fuzzy Color Histogram, edge direction histogram, co-occurrence matrix
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Judul: Purifikasi dan Karakterisasi Mangan Peroksidase (MnP) dari Isolat Leiotrametes flavida Galur ZUL62 dan Cerrena sp
Abstrak: Mangan Peroksidase (MnP) merupakan salah satu enzim ekstraseluler yang dihasilkan oleh jamur pelapuk putih. Leiotrametes flavida galur ZUL62 dan Cerrena sp. merupakan kelompok jamur pelapuk putih. Penelitian sebelumnya menyatakan bahwa kedua jamur tersebut memiliki potensi dalam menghasilkan MnP. Tujuan penelitian ini adalah melakukan purifikasi dan karakterisasi MnP dari kedua isolat. Leiotrametes flavida memiliki aktivitas tertinggi pada hari ke-4 setelah inkubasi, sedangkan Cerrena sp. pada hari ke-5. Aktivitas spesifik tertinggi diperoleh pada fraksi hasil desalting dengan aktivitas sebesar 9456.7 U/mg (Leiotrametes flavida) dan 6555.48 U/mg (Cerrena sp.). pH optimum kedua isolat yaitu pada pH 5, sedangkan suhu optimum Leiotrametes flavida yaitu 40 ºC dan Cerrena sp. 30 ºC. 2,6-Dimethoxyphenol (DMP) digunakan sebagai substrat untuk aktivitas enzim. MnP isolat Leiotrametes flavida memiliki nilai Vmaks 0.55 U/mL dengan km sebesar 1.89x10-1 mM, sedangkan MnP dari Cerrena sp. memiliki nilai Vmaks sebesar 0.1371 U/mL dengan km sebesar 0.096 mM. Penambahan ion Mn2+ dan Mg2+ merupakan ion yang dapat meningkatkan aktivitas untuk kedua isolat. sedangkan ion NaN3 dan Fe2+ dapat menghambat aktivitas enzim dari kedua isolat. galur
Keyword: Cerrena sp, jamur pelapuk putih, Leiotrametes flavida, mangan peroksidase