Judul: Analysis of Body Size Characteristics in Beef Cattle using Principal Component Analysis (PCA)
Abstrak: Penelitian ini bertujuan menganalisis morfometrik dan menentukan penciri utama pada sapi pejantan Peranakan Ongole (PO), Brahman, Angus dan Belgian Blue (BB) di Balai Inseminasi Buatan (BIB) Lembang. Total sampel yang digunakan dalam penelitian ini berjumlah 47 ekor sapi pejantan. Peubah ukuran-ukuran tubuh yang diamati terdiri atas tinggi pundak, panjang badan, tinggi pinggul, lebar pinggul, dalam dada, lingkar dada dan lebar dada. Data pengukuran ukuran-ukuran tubuh dikoleksi di BIB Lembang pada Maret 2021. Data ditabulasi dengan mengoreksi berdasarkan umur dan data dianalisis menggunakan uji t dan analisis komponen utama (AKU). Hasil uji t terhadap ukuran tubuh antara keempat bangsa sapi pejantan sebagian besar menunjukkan perbedaan (P<0.05). Adapun peubah penciri untuk sapi Brahman dan BB tidak memperlihatkan penciri khusus untuk ukuran tubuh. Penciri ukuran tubuh terdapat pada sapi PO, yaitu lebar dada, lebar pinggul, lingkar dada, dalam dada dan panjang badan. Penciri ukuran tubuh dari sapi Angus adalah lebar dada dan lebar pinggul. Hasil penelitian ini diharapkan dapat dijadikan sebagai informasi dasar dalam strategi program pemuliaan ke depan., This study aims to analyze the morphometrics and determine the main characteristics of Ongole Crossed, Brahman, Angus and Belgian Blue (BB) at the Institute for Artificial Insemination Lembang. The number of samples used in this study found 47 bulls. The variables of body measurements observed consisted of whithers height, body length, hip height, rump width, chest depth, chest girth, and chest width. The measurement data was taken in March 2021. Data were tabulated by correcting by age and data analysis using t-test and principal component analysis (PCA). The results of the t-test on body size between the four breeds of bulls mostly shows differences (P<0.05). Meanwhile, the characterizing variables for Brahman and BB cattle did not show specific characteristics for body size. Characteristics of body size found in PO cattle are chest width, hip width, chest girth, chest depth and body length. While Angus cattle are chest width and hip width. The results of this study are expected to be used as basic information in breeding program strategies.
Keyword: AKU, PCA, Ukuran Tubuh, sapi pedaging, Body Size, Beef Cattle

Judul: Evaluation of Linier Body Size Measurement in Different Breeds of Beef Cattle with Digital Imaging Method
Abstrak: Metode citra digital digunakan dalam pengukuran ukuran linier tubuh ternak bertujuan agar ternak tidak stres saat proses pengukuran. Penelitian menggunakan masing-masing 50 ekor sapi pejantan dengan umur I2 (2,5-3 tahun) pada bangsa simmental, limousin dan peranakan angus dengan bobot potong simmental 327-766 kg, limousin 313-920 kg dan peranakan angus 402-782 kg. Data dianalisis dengan menggunakan analisis kovarian, kemudian dilanjutkan dengan Uji Tukey jika terdapat perbedaan antar perlakuan. Hasil penelitian menunjukkan pada ukuran panjang badan nyata lebih tinggi (P<0,05) pada bobot potong sapi simmental, tinggi badan nyata lebih tinggi (P<0,05) pada bobot potong sapi peranakan angus serta ukuran dalam dada dan lingkar dada nyata lebih tinggi (P<0,05) pada bobot potong sapi simmental dan peranakan angus. Evaluasi ukuran permukaan linier tubuh menggunakan metode citra digital pada sapi simmental memiliki nilai korelasi yang sangat kuat daripada sapi limousin dan sapi peranakan angus pada lingkar dada dan dalam dada dengan bobot potong. Ukuran linier tubuh lingkar dada dan dalam dada pada sapi simmental memengaruhi bobot potong., Digital imaging method is used to measure one livestock’s body size without causing any stress. The study used 50 heads of bulls for the simmental, limousine and angus crossbreeds with the age range I2 (2,5-3 years) and slaughter weight of 327-766 kg for simmental, 313-920 kg for limousine and 402-782 kg for angus crossbreds. Data were analyzed using covariance, then tested by Tukey to determine the differences between treatments. The results showed that the measurement of body length has significant effect (P<0,05) in simmental slaughter weight, significant effect (P<0,05) of body height in angus crossbred slaughter weight, and significant effect (P<0,05) of chest weight and chest circumference in Simmental and angus crossbred slaughter weight. Evaluation of linier body size measurement with digital imaging method in simmental bull have correlation value is categorigied as substantial than limousin and angus crossbreed bull of chest circumference and chest weight with slaughter weight. The dimension body size of chest circumference and chest weight for simmental bulls can be used as parameters to determine slaughter weight.
Keyword: bobot potong, citra digital, sapi potong, ukuran linier tubuh

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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