Judul: Kepuasan, Preferensi, dan Willingness to Pay Konsumen terhadap Jeruk Lokal Rimau Gerga Lebong.
Abstrak: Jeruk rimau gerga lebong merupakan varietas jeruk lokal yang dikembangkan di Provinsi Bengkulu dan mendapat perhatian pemerintah daerah Bengkulu untuk dijadikan sebagai komoditias unggulan nasional. Meskipun demikian, jeruk lokal gerga ini menghadapi persaingan dengan produk jeruk lainnya baik jeruk lokal maupun impor dan produk buah-buahan lainnya sebagai pilihan konsumsi masyarakat. Selain termasuk jenis produk jeruk yang baru dipasarkan, jeruk ini memiliki karakteristik produk jeruk yang khas. Oleh sebab itu, pemahaman tentang perilaku konsumen seperti kepuasan dan preferensinya sangat penting bagi penangkar bibit dan pemasar jeruk gerga agar dapat membuat strategi pemasaran sehingga jeruk gerga yang dipasarkan sesuai dengan keinginan dan kebutuhan konsumen jeruk gerga. Tujuan penelitian ini untuk mengidentifikasi proses keputusan pembelian, menganalisis kepuasan, preferensi, dan kesediaan membayar konsumen terhadap jeruk lokal gerga. Jenis data yang digunakan adalah data primer yang diperoleh dari survei daring. Pengumpulan data menggunakan kuesioner dilakukan pada bulan April 2022 dan mendapatkan responden yang berpartisipasi secara sukarela sebanyak 200 orang dengan kriteria responden minimal berusia 17 tahun, pernah membeli dan mengonsumsi jeruk gerga. Data dianalisis menggunakan analisis deskriptif, importance performance analysis (IPA), customer satisfaction index (CSI), discrete choice experiment (DCE), dan willingness to pay (WTP). Pengolahan data menggunakan alat bantu software SPSS Statistic 26 dan StataSE64. Hasil penelitian berdasarkan analisis deskriptif terhadap tahap pengambilan keputusan konsumen diketahui bahwa sebagian besar konsumen menyatakan alasan membeli jeruk gerga karena adanya manfaat dari kandungan jeruk gerga, mendapatkan informasi dari pengalaman pembelian sebelumnya, mempertimbangkan atribut rasa dalam evaluasi sebelum pembelian, memutuskan membeli jeruk gerga karena faktor situasional, melakukan pembelian jeruk gerga dengan jumlah yang banyak per permbelian, dan menyatakan puas dan bersedia melakukan pembelian ulang pasca pembelian. Berdasarkan indeks kepuasan (CSI), hasil penelitian menunjukkan bahwa tingkat kepuasan konsumen terhadap pembelian dan konsumsi jeruk gerga mencapai 75,66%, yang berarti konsumen puas. Berdasarkan diagram kartesius IPA atribut yang menjadi prioritas untuk diperbaiki adalah ketersediaan jeruk dan untuk dipertahankan adalah atribut kesegaran, rasa, dan kandungan air. Berdasarkan analisis DCE, diketahui bahwa konsumen menyukai kombinasi atribut jeruk gerga yang segar, kandungan air tinggi, rasa buah yang manis, dan harga yang murah. Dilihat dari nilai utilitas tertinggi atribut jeruk gerga jika diurutkan adalah atribut kesegaran (2,321), kandungan air yang juicy (1,234), rasa manis (0,763), dan untuk harga yang mahal memiliki nilai utilitas negatif (-0,002). Berdasarkan analisis WTP konsumen bersedia membeli jeruk dengan harga maksimum terhadap jeruk yang segar, juicy, dan manis, untuk kesegaran jeruk sebesar Rp936,08/kg, kandungan air Rp497,59/kg, dan untuk rasa manis sebesar Rp307,89/kg., Rimau gerga orange is a local oranges variety developed in Bengkulu Province and received the attention of the Bengkulu regional government to be used as a superior national commodity. Even so, the local oranges of this gerga face competition from other orange products, both local and imported oranges and other fruit products, as the people's choice of consumption. Gerga orange fruits with different characteristics of orange attributes and have only been marketed to consumers for a few years make this research interesting. Considerations made by consumers towards purchasing gerga oranges, information is needed regarding consumer behavior in purchasing and post-purchase gerga oranges. Knowing consumer behavior is very useful for gerga orange breeders
Keyword: preference, purchase decision, satisfaction, willingness to pay

Judul: Analisis persepsi dan preferensi konsumen terhadap Jeruk Keprok Garut di Kabupaten Garut, Jawa Barat
Abstrak: In 1980 Jeruk Keprok Garut became the best local orange comodity and either had good quality and competitiveness with Jeruk Pontianak and Jeruk Medan. Jeruk Keprok Garut started to be less known by Indonesian after infected by Citrus Vein Phloem Degeneration (CVPD) and erupted of Gunung Galunggung in Tasikmalaya. And The Huge number of imported Orange in our market was supporting the reason why Jeruk Keprok Garut were being less known by local community (Indonesian).This study/research is intended to investigate the consumer characters, consumer perception and consumer preference toward Jeruk Keprok Garut. Based on the investigation, we obtained some conclusion that consumer characteristics were mostly women, especially who lived in the Districts around the City Center, who were have age around 25-35 years old, married and working with income of above Rp 2 000 000, Consumer was seeing that Jeruk Keprok Garut has a taste of fresh sweet with a little of acidity. It has high water content, clean yellow-green skin, fresh and strong aroma. The price was also relatively affordable and easily found in around Garut City Center (urban areas). Consumer preferences is measured by the Method of Conjoint, which shows that consumer are more inclined to chooseJeruk Keprok Garut with combinations of low price attributes that have range at the lowest price in the market of Rp 13 000- Rp 17 000 per kilogram, sweet taste, watery, and fresh aroma.
Keyword: Bogor Agricultural University (IPB), Conjoint., Jeruk Keprok Garut, Perception and Preference

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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