Integrated inventory model for three–layer supply chains with stochastic demand

In this paper, we consider three–stage inventory production system in three–layer supply chain with equal–sized shipments and incorporating raw material procurement. The vendor converts raw material, which is ordered from supplier, to finished product and delivers it to the buyer. We assume that the demand in buyer's side is stochastic and shortage is allowed. The objective is to minimise the expected total cost incurred by the vendor and the buyer. We derive expected total joint cost function and propose solution procedure to determine the optimal policy. Finally, we present numerical examples to illustrate the significance of cost reduction of the integrated model in comparison with independent model

A Cooperative Inventory Model for Vendor-Buyer System with Raw Material Decisions, Deterministic Lead Time and Stochastic Demand

This study investigates integrated inventory problem for a two-stage supply chain consisting of a single vendor and single buyer. We develop a model for coordinating the replenishment decisions for raw material procurement, production, and shipment under stochastic environment. For attaining the model objective, we develop an algorithm to determine the optimal shipment-sized, safety factor, number of shipment and number of raw material replenishment based on minimum expected total cost. Furthermore, numerical examples are given to illustrate the effect of primary parameters on the lot size, safety factor, number of batches and expected total cost. The results from numerical examples shows that making production-inventory decisions jointly can reduces expected total cost comparing with making decisions individually. Keywords: Supply chain, replenishment decision, raw material procurement, production, shipment, stochastic

Model Joint Economic Lot Size (JELS) pada Kasus Pemanufaktur-Pembeli dengan Permintaan Probabilistik dan Lead Time Variabel

We consider a two-layer supply chain model consisting of a vendor and a buyer. The buyer observes a probabilistic demand and orders lots from the vendor. We relax the assumption of deterministic lead time and assume that it is varying linearly with the delivery lot size. The vendor manufactures the requested product in production batchs. Each produces batch is shipped to the vendor produces in a multiple integer of delivery quantity and hence, an order can be split into a number of production runs. A solution procedure is suggested for solving the proposed model and numerical examples are used to illustrate the benefit of integration. Numerical results show that the integrated inventory model will always result in savings in the total joint cost, buyer cost and vendor cost

Pengukuran Fleksibilitas Dalam Industri Manufaktur Dengan Menggunakan Objective Matrix (OMAX) dan Entropy

As globalization of markets raises competitive pressures, one essential requirement for the survival of organizations is their capability to meet competition. Market needs cause unceasing changes in the life cycle, shape, quality and price of products. Manufacturing flexibility is an effective way to face up to the uncertainties of this rapidly changing environment and it is defined as the ability to absorb various disturbances which occur in production systems, as well as the ability to incorporate and exploit new technological advances and work practices. The aim of this paper is to measure capability and requirement of flexibility in manufacturing system. We propose Objective Matrix (OMAX) and Entropy integration method to measure flexibility. Keywords : flexibility, objective matrix, entrop

Pengembangan Model Persediaan Single Vendor-Single Buyer dengan Lead Time Dapat Dikontrol

In this paper we consider the single vendor-single buyer integrated inventory model. We relax the assumption of deterministic demand and assume that it is stochastic. We also consider the buyer’s lead time can be shortened at an extra crashing cost which depends on the lead time length to be reduced. We develop effective iterative procedures for finding the optimal policy

Perancangan Peta Evakuasi Menggunakan Algoritma Floyd- Warshall untuk Penentuan Lintasan Terpendek: Studi Kasus

Abstrak Peta evakuasi sangat penting bagi suatu rumah sakit. Hal ini dikarenakan untuk mengurangi resiko saat terjadi bencana (gempa bumi) dan sebagai syarat akreditasi untuk memperoleh akreditasi suatu rumah sakit. Penelitian ini bertujuan untuk menyusun peta evakuasi dan penandaannya. Dengan perancangan peta evakuasi, diharapkan dapat terpenuhi salah satu syarat akreditasi rumah sakit dan memudahkan penghuni bangunan rumah sakit dalam mencari jalan tercepat saat keadaan darurat atau keadaan bahaya. Terdapat dua tahap dalam perancangan peta evakuasi. Tahap yang pertama ialah perancangan alur evakuasi dengan menggunakan Algoritma Floyd-Warshall untuk menentukan lintasan terpendek. Tahap kedua ialah penandaan peta evakuasi. Tahap pertama terdiri dari enam tahap, yaitu pembuatan block plan Rumah Sakit Umum Daerah Kabupaten Kebumen, penentuan letak titik berkumpul (assembly point), penentuan node, pemilahan titik berkumpul (assembly point) untuk masing-masing ruang, penentuan jarak masing-masing ruang ke titik berkumpul (assembly point), dan penentuan alternatif evakuasi. Tahap kedua merupakan perancangan penandaan peta evakuasi. Dalam hal ini, warna dan bahan penandaan peta evakuasi sesuai dengan Rumah Sakit Islam Surakarta. Penandaan peta evakuasi dibuat dari bahan acrlylic dan dipasang sepanjang jalur evakuasi. Hasil penelitian menunjukkan bahwa terdapat 40 ruang yang dapat langsung ditentukan lintasan evakuasinya dan 35 ruang ditentukan lintasan terpendeknya dengan menggunakan Algoritma Floyd-Warshall. Dari ketiga puluh lima ruang itu, 16 ruang menuju titik berkumpul sebelah utara, 5 ruang menuju titik berkumpul sebelah barat, dan 14 ruang menuju titik berkumpul sebelah selatan. Sehingga titik berkumpul sebelah utara menampung 39 ruang, titik berkumpul sebelah barat menampung 19 ruang, dan titik berkumpul sebelah selatan 17 ruang serta peta evakuasi telah disusun dan akan dipasang di tempat-tempat strategis sepanjang jalur evakuasi

Penentuan Faktor-Faktor Bahaya yang Dihadapi Perawat di RSUD Kabupaten Karanganyar dan Usulan Pencegahannya Menggunakan Metode AHP

From the calculation of weighting the results of biological hazard 0.23 0.22 followed by a chemical hazard and environmental and mechanical biomechanical hazard 0.22, 0.17 and hazard pshycal 0.17 pshychological hazard. While the determination of the value of performance, the lowest hazard of pshychological hazard to the value 3.991 4.113 followed by a biological hazard, chemical hazard 4.309, environmental and mechanical / biomechanical hazard and the highest 4.396 4.578 pshycal hazard. Proposed hazard prevention based on the lowest of pshychological hazard with hazard specification, among others, due to the many patients, patients who want immediate demands are met, the threat from the patient and the supervisor, invective from the patient and the supervisor, shift changing, the staff were not adequate and heavy workloads. From the results of questionnaires and interviews with the nurse, the things that need to be considered is the quantity of hospital nurses, nurses and quality of work on the hospital system

Perancangan Sistem Pengukuran Kinerja Organisasi Non Profit (Studi Kasus pada UTDC PMI Surakarta)

Abstract In this paper we developed performance measurement system in UTDC PMI Surakarta. We used Integrated Performance Measurement System (IPMS) methodology which based on stackeholder’s requirement, to design the measurement system. From the design process, it can be identified 8 stakeholders, and based on stakeholder’s requirements, it can be obtained 27 requirements and 7 objectives. Furthermore, we developed 19 key performance indicators (KPIs) which can be classified into 6 aspects, including donor, human resources, blood preparation, output, administration, and control and evaluation.Finally, we conducted Analythic Hierarchy Process (AHP) method to weight the all aspects and KPIs. It was found that human resources(0.435) was most importance aspect and employee’s performance achievement (0.24) became most importance indicator among them. Keywords : Integrated Performance Measurement System (IPMS), stackholder’s requirement, key performance indicator (KPI), Analythic Hierarchy Process (AHP)

Determination Inventory Level for Aircraft Spare Parts Using Continuous Review Model

In this paper, we determine ordering quantity and reorder point for aircraft consumable spare parts. We use continuous review model to propose a spare part inventory policy that can be used in a aircraft maintenance company in Indonesia. We employ ABC classification system to categorize the spare parts based on their dollar contribution. We focus our research on managing the inventory level for spare parts on class A and B which commonly known as important classes. The result from the research indicates that the continuous review policy gives a significant amount of saving compared to an existing policy used by the company

Analisis Sistem Antrian di Plasa Telkom Solo dengan Metode Simulasi

Abstract Plasa Telkom Solo is a service place belonging to Telkom which is provided to serve Telkom customer with nine service servers. Those nine services servers can handle new setting and mutation, complains, information, and cash payment and non cash payment. Queue in the scale of customer service is important to be considered because the long queue will make the customer uncomfortable. The queue happens because the need of service is bigger than the capacity of service. Therefore, the customer cannot be served immediately because the busy service. This research is conducted to analyze the queue system to find the best number of the server and service system in Plasa Telkom Solo. This research uses simulation method to find the best solution for the company to decide the number of the servers. The simulation model is used because this model can give solution if analytic model is failed to do that. Analytic model cannot be used in this research since in Plasa Telkom Solo there are four kinds of service with different approximate time service. Based on the research, the best numbers of server is seven. Meanwhile, the service system model are combining service 1 (new setting and mutation) and service 2 (complain) with the number of server 5 and service 3 (information) combines with service 4 (cash payment and non cash payment) with number of server is 2. This model can reduce the queue time for 21,7325 minutes (before the simulation) to be 17,8694 minutes (after simulation). The time difference is 3.8631 minutes with utilization 0,8996 (89,96%) or 458,796 minutes (7,65 hours) per day and the free time for the server is 0,1004 (10,04%) atau 51,2040 minutes (0,85 hours) per day, in which per day there is 8,5 work time. Key Words: Server, service kind, queues time, server free time, simulation, model