INTEGER RELAXATION ON BINARY QUADRATIC PROGRAMMING FOR BATCHING AND SEQUENCING IN SINGLE FORMULATION TO MINIMIZE TOTAL ACTUAL FLOW TIMES CRITERIA

This paper examines batch scheduling problem that has batching and sequencing in single formulation for multiple-item case. The first step is to develop a model for single item single resource discussed in Zahedi (2008). The model determined batch sizes and their schedule simultaneously in single item case. This paper develops the model and algorithm for multiple-item case. The model functions to minimize total actual flow times. An algorithm for the model is developed using a relaxation of the binary constraints. The binary values for the decision variables are obtained from steps provided in algorithm. A numerical experience showing characteristics of this problem is presented

METODE PENGENDALIAN PERSEDIAAN BAHAN BAKU CRUDE COCONUT OIL YANG OPTIMAL PADA PT. PSE

Sistem persediaan merupakan salah satu fungsi manajerial yang sangat penting, karena mayoritas perusahaan melibatkan investasi besar pada aspek ini, demikian juga bagi PT. Palko Sari Eka yang banyak menggunakan persediaan dalam bidang perencanaan dan pengendalian produksinya. PT. Palko Sari Eka sebagai salah satu perusahaan yang bergerak dalam industri oil refinery, ingin mencoba mengoptimalkan inventory bahan baku Crude Coconut Oil dengan mencoba membandingkan berbagai metode pengendalian persediaan seperti metode EOQ (Economic Order Quantity, metode EOI (Economic Order Interval), metode Min-Max. Dimana Crude Coconut Oil merupakan salah satu bahan baku utama produk, yang membutuhkan suatu sistem persediaan yang baik. Dari hasil penelitian yang dilakukan, ternyata data demand bersifat stochastic, maka perlu juga melakukan simulasi untuk mendapatkan hasil yang lebih mendekati kenyataan. Kemudian dari hasil formulasi rumus dan hasil dari simulasi dianalisa manakah metode pengendalian persediaan yang paling baik. Maka didapatlah hasil bahwa metode yang paling baik adalah Fixed Order Size Systems (EOQ) dengan melakukan pesanan sebesar 2770 mT setiap pesananny

On a Deterministic Property of the Category of kk-almost Primes: A Deterministic Structure Based on a Linear Function for Redefining the kk-almost Primes (∃n∈N\exists n\in {\rm N} , 1≤k≤n1{\le} k {\le}n) in Certain Intervals

In this paper based on a sort of linear function, a deterministic and simple algorithm with an algebraic structure is presented for calculating all (and only) $k$-almost primes ($where$ $\exists n\in {\rm N}$, $1{\le} k {\le}n$) in certain interval. A theorem has been proven showing a new deterministic property of the category of $k$-almost primes. Through a linear function that we obtain, an equivalent redefinition of the $k$-almost primes with an algebraic characteristic is identified. Moreover, as an outcome of our function's property some relations which contain new information about the $k$-almost primes (including primes) are presented.Comment: 10 pages. Accepted and presented article in the 11th ANTS, Korea, 2014. The 11th ANTS is one of international satellite conferences of ICM 2014: The 27th International Congress of Mathematicians, Korea. (Expanded version

Analyzing readerships of International Iranian publications in Mendeley: an altmetrics study

In this study, the presence and distribution of both Mendeley readerships and Web of Science citations for the publications published in the 43 Iranian international journals indexed in Journal Citation Reports have been investigated. The aim was to determine the impact, visibility and use of the publications published by the Iranian international journals in Mendeley compared to their citation impact; furthermore, to explore if there is any relation between these two impact indicators (Mendeley readership counts and WoS citation counts) for these publications. The DOIs of the 1,884 publications used to extract the readerships data from Mendeley REST API in February 2014 and citations data until end of 2013 calculated using CWTS in-house WoS database. SPSS (version 21) used to analyze the relationship between the readerships and citations for those publications. The Mendeley usage distribution both at the publication level (across publications years, fields and document types) and at the user level (across users disciplines, academic status and countries) have been investigated. These information will help to understand the visibility and usage vs citation pattern and impact of Iranian scientific outputs.Comment: in Persia

Model Terintegrasi Penjadwalan Batch dan Pm dengan Kriteria Minimalisasi Biaya Simpan, Setup dan Pm pada Mesin dengan Increasing Failure Rate

Development of today's manufacturing systems leads to the getting shorter in product life cycle, more variety of products, as well as increasing in consumer demand for quality and timeliness. Thus the accuracy and speed of decision-making within the manufacturing system becomes important. This paper proposes an integrated model of batch scheduling and preventive maintenance scheduling, in assumption no non-conforming parts to the criteria of minimizing the total saving cost, setup cost, preventive maintenance cost in minimizing the actual flow time on a machine with increasing failure rate. An example is provided to show how the model and algorithm work

Hybrid dynamic modeling of 4-CBA hydrogenation fixed-bed catalytic reactor of PTA production plant

In this paper, a dynamic hybrid model of 4-carboxybenzaldehyde (4-CBA) hydrogenation fixed-bed catalytic reactor of Purified Terephthalic Acid (PTA) production plant has been developed. At the first step, the deactivation model of the reaction system has been predicted by using artificial neural network (ANN) technique. Then, the deactivation model estimated by ANN as black box incorporated to first principle model (FPM) as white box. Therefore, the established hybrid model has been utilized to model the hydrogenation reactor of PTA plant. Finally, the simulated results have been compared with the industrial reactor data. It has been concluded that hybrid model is more precise than a FPM model