Judul: Pengendalian Persediaan Perishable Food dengan Metode Economic Order Quantity
Abstrak: Kualitas dari suatu bahan makanan perishable dipengaruhi oleh masa simpan bahan makanan tersebut. Bahan makanan dengan masa simpan yang lebih lama lebih disukai bagi konsumen. Kualitas bahan makanan perishable menurun seiring dengan umur bahan makanan tersebut. Sebuah perusahaan memerlukan waktu optimal dalam melakukan pemesanan agar bahan makanan perishable dapat dijual dengan kualitas yang pantas untuk memaksimalkan keuntungan. Salah satu metode dalam menentukan waktu pemesanan optimal yaitu dengan Economic Order Quantity (EOQ). Model EOQ dengan laju permintaan yang dipengaruhi umur simpan dikembangkan untuk mendapatkan waktu pemesanan optimal selama periode umur bahan makanan perishable. Laju permintaan diasumsikan sebagai fungsi turun secara linear terhadap umur bahan makanan tersebut. Penelitian ini menghasilkan formulasi masalah persediaan untuk menentukan panjang siklus pemesanan optimal agar memaksimalkan keuntungan. Formulasi tersebut menghasilkan perkiraan margin kontribusi untuk bahan makanan perishable agar keuntungannya dapat bersanding dengan bahan makanan non-perishable., Quality of perishable food is affected by its lifetime. Perishable food with a longer lifetime is preferable for consumers. The quality of perishable food decreases during its lifetime. A company needs an optimal time to place orders so that perishable food can be sold at acceptable quality in order to maximize profit. One method to determine the optimal ordering time is the Economic Order Quantity. EOQ model with age-dependent demand rate was developed to obtain optimal ordering time during the perishable food’s lifetime. The demand rate is assumed to be a linearly decreasing function to the lifetime of perishable food. This study resulted in the formulation of the inventory problem to determine the optimal ordering cycle length in order to maximize profits. The formulation produces an estimate contribution margin for perishable food so that the profit can be compared to non-perishable food.
Keyword: contribution margin, inventory control, optimal ordering cycle length, perishable EOQ model

Judul: Pengoptimuman Masalah Persediaan dengan Tingkat Kerusakan Konstan, Backorder, dan Permintaan Merupakan Fungsi Kuadratik dari Harga
Abstrak: Persediaan barang merupakan suatu kegiatan yang penting dilakukan dalam rangka memberikan pelayanan terhadap konsumen. Terdapat jenis barang yang dapat mengalami kerusakan sehingga menimbulkan biaya kerusakan. Terkadang permintaan juga menyebabkan kekurangan persediaan (backorder) sehingga perusahaan harus mengeluarkan biaya kekurangan. Selain itu, perusahaan juga harus mengeluarkan biaya penyimpanan. Pada penelitian ini akan divalidasi model persediaan Economic Order Quantity dengan tingkat kerusakan konstan, adanya backorder, dan permintaan merupakan fungsi kuadratik dari harga serta mengimplementasikan model pada beberapa contoh kasus. Pada penelitian ini akan dibahas empat jenis fungsi permintaan dan akan ditentukan solusi masalah persediaan yang meminimumkan biaya. Selain itu, akan dianalisis pengaruh perubahan nilai dari biaya kekurangan per unit, biaya penyimpanan per unit, biaya kerusakan per unit, waktu pemesanan persediaan, dan harga jual barang terhadap besaran lain., Inventory is an important activity to provide services to consumers. There are several types of things that can be deteriorated, causing the company to bear the deteriorating cost. Sometimes demand also causes a shortage of inventory (backorder) so the company must incur shortage cost. In addition, the company must also incur holding cost. In this research, will be validated the Economic Order Quantity model with a constant level of deterioration, there is a backorder, and demand is a quadratic function of price, and implement the model in sample cases. In this research, will be discussed four types of demand functions and determined a solution of the inventory problem that minimizes costs. In addition, it will analyze the effect of shortage cost per unit, holding cost per unit, deteriorating cost per unit, scheduling period, and selling price to other variables.
Keyword: deteriorate, EOQ model, inventory optimization, quadratic function

Judul: Posisi Filogenetik Kura-Kura Carettochelys Insculpta  (Reptillia: Testudinata)
Abstrak: Carettochelys insculpta is an endemic freshwater turtle of southern Papua and northern Australia. Phylogenetic position of this turtle is remain unresolved until now. Most of the research conducted show close relationships of C. insculpta and members of Trionychidae family. However, some of the research show distance between C. insculpta and members of Trionychidae family. This research is conducted to analyze phylogenetic relationship between C. insculpta and other members of Testudinata using 12S rRNA, 16S rRNA, and both gene as markers. DNA samples were obtained from three different organisms of C. insculpta. Two species used as outgroups were Alligator mississippiensis and Iguana iguana. Phylogenetic analysis was carried out using Neighbor-Joining method with Felsenstein 1981 (F81) modeltest. A polytomy tree of Testudinata was produced by using 12S rRNA gene. However, analysis using 16S rRNA and both genes as markers confirmed that C. insculpta was located between the Chelonidae and the Trionychidae family.
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