Judul: Faktor-Faktor yang Memengaruhi Keputusan Pembelian Buku Pada Mahasiswa
Abstrak: Penerbit dan toko buku mengalami penurunan penjualan buku dari tahun 2013 sampai 2020. Dalam penelitian ini peneliti ingin mengetahui apakah faktorfaktor yang menyebabkan penjualan buku mengalami penurunan. Penelitian ini bertujuan mencari faktor-faktor apa saja yang memengaruhi mahasiswa dalam membeli buku. Ada berbagai faktor yang memengaruhi dalam keputusan pembelian buku, yaitu: faktor harga, produk, lokasi, promosi, gaya hidup, word of mouth teknologi, dan informasi. Penelitian ini menggunakan 205 responden yang merupakan mahasiswa IPB University. Teknik pengumpulan data yang digunakan adalah Probability sampling yaitu metode pengambilan sampel secara random atau acak. Pemilihan sampel dengan menggunakan convinience sampling yaitu teknik penarikan sampel dari orang atau unit yang paling mudah dijumpai atau diakses. Metode penarikan sampel menggunakan metode wawancara dan mengisi kuesioner pada google form. Penelitian menggunakan alat uji SEM PLS. SEM (Structural Equation Models) merupakan teknik statistik yang bertujuan untuk membangun maupun menguji model statistik yang biasanya dalam bentuk model sebab akibat. Penelitian ini merupakan bidang ilmu perilaku konsumen. Penelitian dilakukan di kampus Institut Pertanian Bogor bulan Desember 2020 sampai April 2021. Lokasi penelitian dipilih secara sengaja (purposive) karena obyek penelitiannya adalah mahasiswa Institut Pertanian Bogor yang aktif. Hasil penelitian menunjukkan bahwa faktor produk, harga, word of mouth, gaya hidup, teknologi, dan informasi berpengaruh secara positif dan signifikan terhadap keputusan pembelian buku pada mahasiswa. Faktor lokasi, dan promosi tidak berpengaruh secara signifikan terhadap keputusan pembelian buku pada mahasiswa., Publishers and bookstores declined in book sales from 2013 to 2020. The study aimed to find out factors that caused book sales declined and students influencing factors in buying books. There are various factors that influencing the decision to purchase books, i.e price, product, location, promotion, lifestyle, word of mouth technology, and information. This study used 205 respondents who are students of IPB University. The data collection technique used is Probability sampling, a random sampling method. Sample selection using convenience sampling is a sampling technique from the person or unit that is the easiest to find or access. The sampling done by the interview method and filled out a questionnaire on the google form. PLS SEM test tool used to data analysis. SEM (Structural Equation Models) is a statistical technique that aims to build or test statistical models, which are usually causal This research is a field of consumer behaviour science. The research was conducted on the Bogor Agricultural University campus from December 2020 to April 2021. The author chose the location of this research purposively because the object of the research was active Bogor Agricultural University students The study results showed that the product, price, word of mouth, lifestyle, technology, and information factors had a significant effect on students buying book decisions. Location and promotion factors have no significant effect on students purchase book decisions.
Keyword: books, student, purchase decisions, buku, toko buku, keputusan pembelian

Judul: Analisis faktor-faktor yang berpengaruh terhadap sikap dan perilaku membeli buku bajakan pada mahasiswa IPB
Abstrak: The aim of research is to analyse factors which influence IPB students attitudes and buying behaviour of piracy book. Research methode using cross sectional study design. Data aggregation along Mei 2009. Data was taken from 200 sample girls and boys with equilibrate. The way of taking out sample from every faculty appropiete with proportional sampling. Obtainable data is primery data and secondary data. Tabulation and analysis data by description and statistic test (mann withney/ T test, double linier regression with backward method and logistic regression test with entered method). Almost samples are readed book and mostly they buy a book for the last three months. Almost of them is had knowledge with average value. For the samples attitude that quite netral about book piracy. Their basic reason that piracy book is cheaper than the original. From the result can show the factors that influencing attitude concerning book piracy is amount of ages, allocation of money, information resources, and knowledge. The factor that influencing behavior buying of piracy book is attitude.
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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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