Judul: Habitat characteristics of timor friarbird philemon inornatus in Camplong Landscape Kupang District, East Nusa Tenggara
Abstrak: Timor Friarbird (Philemon inornatus, G. R. Gray, 1846) is one of the six endemic birds of Timor and is a protected species. The population of bird is suspected to have been decreasing over the past six years along with the decreasing of the quantity and quality of physical and biotic factors of its habitat. Knowledge on landscape spatial pattern could be used to evaluate the quantity and quality of habitat. This research aimed at identifying spatial habitat characteristics of Timor Friarbird based on dominant factors of physical and biotic habitat components. Principle Component Analysis (PCA) on the physical habitat factors showed that variables that have strong correlation with the presence of the bird were Normalized Difference Vegetation Index (NDVI), slope, distance from secondary forest, distance from bush, distance from cashew plantation, distance from crop plantation, and distance from roads. The biotic factors that have strong correlation with the presence of Timor Friarbird were the total number of plant species, number of plants used for food and cover, and mean height of trees. Height of poles was the only variable that has no correlation with the presence of Timor Friarbird. The most dominant physical and biotic factors that influent the presence of Timor Friarbird at a site are the density of foraging trees, slope, distance from the river, the distance from secondary forest, the density of cover pole and the distance from road. The estimation population of Timor Friarbird in Camplong region is low; this might be caused by low feeding tree density, high rates of poaching, the uneven distribution of feed vegetation and the flowering season, habitat degradation due to illegal logging, grazing cattle in the wild, and invasion of siam weed or chromolaena (Chromolaena odorata). The results of land cover classification at Camplong region based on Landsat_5 Thematic Mapper (TM) image with ArcGIS 9.3 and Erdas 9.1 obtained 11 land cover classes, with shrub as the dominant class. Keyword: Philemon inornatus, Habitat Spatial Characteristics, PCA, Population, Land Cover
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Judul: Keanekaragaman jenis burung pada beberapa tipe habitat di Tambling Wildlife Nature Conservation (TWNC), Taman Nasional Bukit Barisan Selatan Lampung
Abstrak: Tambling Wildlife Nature Conservation (TWNC) is part of the Bukit Barisan Selatan National Park. The area called Tambling (Tampang-Belimbing) is a conservation area that conserve high biodiversity. TWNC is managed by PT Adhiniaga Kreasinusa (AKN). The purposes of this research are 1). to compare the diversity of bird species at several types of habitat in TWNC, those are coastal forest, lowland forest, plantation and grassland. 2). to identify the difference of bird species composition among types of habitat. 3). to know the local birds distribution related to the types of habitat in TWNC. This research was conducted from August to November 2009. Data of birds was collected using MacKinnon species list and point count method or IPA (Ponctuel Indices d'Abondance). Data of habitat was collected using vegetation analysis and habitat used approach. Data of vegetation was collected by sampling plot 20 x 100 m. T-test was used to determine differences in bird species diversity among the coastal forest, lowland forest, plantation, and grassland habitats at the 95% confidence level. The vegetation in the coastal forest habitat was dominated by beach hibiscus (Hibiscus tiliaceus) with Important Value Index (IVI) 114.49%. In the lowland forest habitat was dominated by meranti (Shorea sp) with IVI 66.71%. Vegetation in plantation habitat consisted of coffee (Coffea robusta) and cacao (Thebroma cacao). Grassland habitat is dominated by species kerawatan (Cyonodon dactylon) and rumput jarum (Andropoghon aciculatus). The total bird species found in four types of habitat were 116 species, comprising 38 families. Twenty-eight species are categorized as protected by Indonesian government regulation No. 7 of 1999, 12 species are listed in the IUCN (Critically Endangered and Near Threatened), and 19 species are listed in CITES (Appendix I and II). The highest bird Diversity Index was found in plantation habitat (H’=2.93). The Evenness Index in four habitat types are distributed evenly. The habitats that have the highest similarity are between lowland forest and plantation habitats (ISJ=0.54). T-test results shows that there is no significant differences among four habitats in terms of birds diversity, it was predicted because of small sample size and a narrow area of research. Bird species in each habitat type has a different level of dominance. Regarding vertical distribution, birds in coastal forest lived in C to E strata. Vertical distribution of birds in lowland forest was found in A to E strata. Vertical distribution of birds in plantation habitat was found from C to E strata. While in grassland habitat birds were only found in E strata. The common bird activities were perching, singing, flying, and walking. Bird activity that was mostly found at coastal forest, lowland forest, and plantation was perching. At grassland habitat, common bird activity was walking.
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Judul: Perbandingan algoritma message digest 5 (md5) dan secure hash algorithm 1 (Sha1) untuk autentikasi pesan
Abstrak: Seiring dengan meningkatnya penggunaan internet sebagai media pertukaran pesan, metode pengamanan pesan menjadi sangat penting. Nilai suatu pesan yang ingin dijaga keutuhan atau integritasnya menyebabkan pesan tersebut hanya boleh dimodifikasi oleh pihak yang berhak. Namun pada realitanya, pesan tersebut akan mendapat ancaman dari scorang penyusup. Bentuk ancaman terjadi apabila penyusup dengan suatu cara, dapat mengubah isi pesan tersebut untuk berbagai kepentingan. Apabila isi pesan telah berubah dari bentuk aslinya, maka pesan tersebut dikatakan sudah tidak autentik (asli) lagi. Suatu metode yang efektif untuk menguji keautentikan suatu pesan digunakan teknik kriptografi. Pada karya ilmiah ini akan dibahas algoritma Message Digest 5 (MD5) dan Secure Hash Algorithm (SHAI) untuk autentikasi pesan. Tulisan ini bertujuan untuk mempelajari cara kerja kedua algoritma tersebut, yaitu untuk memroses input sehingga dihasilkan message digest, dan kemudian membandingkan kedua algoritma tersebut ditinjau dari segi teori, keamanan atau daya tahan kedua algoritma tersebut terhadap attack, analisis algoritma dan hasil implementasi (kecepatan). Dari kedua algoritma tersebut dapat ditentukan algoritma terbaik dengan asumsi bahwa kedua algoritma tersebut dibandingkan menurut keamanannya Analisis terhadap algoritma MD5 dan SHA1 menunjukkan keduanya mempunyai kasus terburuk dari proses hash pesan adalah O(n). Proses operasi setiap blok 512 bit pada algoritma SHAI lebih banyak dibandingkan algoritma MD5, hal ini mempengaruhi kecepatan kedua algoritma tersebut. Dari hasil implementasi didapatkan bahwa algoritma MD5 lebih cepat dibandingkan SHA1. Dari segi keamanan, ditinjau dari panjang outputnya, algoritma SHA1 mempunyai panjang output 160 bit, sedangkan MD5 128 bit. Ini berarti, algoritma SHA1 akan lebih tahan terhadap brute force attack dan birthday attack jika dibandingkan dengan MD5. Ditinjau dari daya tahan algoritma terhadap attack, pada algoritma SHA1 tidak ditemukan attack lain yang dapat memecahkan algoritma tersebut, sedangkan pada algoritma MD5, ditemukan Boer-Boessalaers attack yang menunjukkan adanya pseudocollision pada fungsi kompresi MD5. Oleh karena itu, salah satu prinsip dasar perancangan algoritma hash yaitu collision resistance tidak terpenuhi. Walaupun, collision tersebut tidak terjadi pada algoritma MD5 secara keseluruhan, namun hal ini menunjukkan kelemahan pada fungsi kompresi MD5. Meskipun algoritma MD5 lebih cepat, namun algoritma SHA1 lebih aman. Untuk aplikasi yang membutuhkan collision resistant, algoritma SHA1 baik untuk digunakan.
Keyword: penggunaan internet, messages, algoritma Message Digest 5 (MD5), Secure Hash Algorithm (SHAI)