A SINGLE-VENDOR SINGLE-BUYER INTEGRATED PRODUCTION-INVENTORY MODEL WITH QUALITY IMPROVEMENT AND CONTROLLABLE PRODUCTION RATE

2017 ◽  
Vol 80 (1) ◽  
Author(s):  
Wakhid Ahmad Jauhari
Keyword(s):  
Quality Improvement ◽  
Production Rate ◽  
Capital Investment ◽  
Production Capacity ◽  
Success Factor ◽  
Lot Size ◽  
Improvement Program ◽  
Defective Items ◽  
Total Cost ◽  
Single Vendor

In the classical vendor-buyer inventory models, the common unrealistic assumption is that all the items manufactured are in good quality. However, in reality, it can be observed that there may be some defective items produced and then delivered to the buyer. Thus, the existence of defective items would consequently give significant influence to system behavior. In addition, a manufacturing flexibility such as the capability to adjust production capacity becomes a key success factor for increasing system flexibility as well as reducing total cost. Here, we investigate how a quality improvement program and adjustable production rate can help the supply chain to reduce the total cost. This paper studies the effect of quality improvement and controllable production rate in joint economic lot size model consisting of single-vendor and single-buyer under stochastic demand. The model gives allowance to the vendor to adjust production rate and also to invest an amount of capital investment to reduce the defect rate. The lead time is comprised of production time and setup and transportation time. The model also considers a situation in which the shortages in buyer side are assumed to be partially backordered. To solve the model, an iterative algorithm is proposed to determine simultaneously safety factor, delivery lot size, delivery frequency, production rate and process quality for minimizing total cost is proposed. The result from this study shows that allowing the vendor to both adjust the production rate and reduce the defective product by adopting quality improvement policy can reduce the individual and total cost. In the example given, the proposed model gives significant total cost saving of 45.9% compared to the model without controllable production rate and quality improvement.

scholarly journals Model Persediaan Pemasok-Pembeli Dengan Produk Cacat Dan Kecepatan Produksi Terkontrol.

2016 ◽  
Vol 15 (2) ◽  
pp. 103
Author(s):  
NELITA PUTRI SEJATI ◽  
WAKHID AHMAD JAUHARI ◽  
CUCUK NUR ROSYIDI
Keyword(s):  
Sensitivity Analysis ◽  
Production Rate ◽  
Lead Time ◽  
Demand Uncertainty ◽  
Lot Size ◽  
Defective Items ◽  
Total Cost ◽  
Joint Economic Lot Size ◽  
Demand Rate ◽  
The Impact

Penelitian ini mengembangkan model persediaan Joint Economic Lot Size (JELS) pada pemasok tunggal pembeli tunggal untuk jenis produk tunggal dengan mempertimbangkan produk cacat dan tingkat produksi terkontrol. Tingkat permintaan pada pembeli bersifat stokastik. Pengiriman dilakukan dari pemasok ke pembeli dalam ukuran lot pengiriman yang sama dan lead time pengiriman bersifat tetap. Produk cacat yang ditemukan oleh pembeli pada saat inspeksi disimpan secara sementara di gudang pembeli hingga pengiriman berikutnya tiba untuk selanjutnya produk cacat dikembalikan kepada pemasok. Fungsi tujuan dari model ini adalah meminimasi total biaya persediaan gabungan pemasok pembeli dengan variabel keputusan, yaitu frekuensi pengiriman, periode review, dan tingkat produksi. Analisis sensitivitas dilakukan untuk melihat pengaruh perubahan parameter-parameter tertentu terhadap model. Hasil yang didapatkan dari analisis sensitivitas menunjukkan bahwa total biaya persediaan gabungan sensitif terhadap perubahan nilai parameter persentase produk cacat, ketidakpastian permintaan, dan permintaan. In this paper, we consider a joint economic lot size (JELS) model consisting of single vendor single buyerwith single product. We intend to study the impact of defective items and controllable production rate onthe model. The demand in buyer side is assumed to be stochastic. The delivery of lot from vendor to buyer is conducted under equal size shipment and the lead time is assumed to be constant. The defective items founded by the inspector in buyer side are carried in buyer’s storage until the next shipment and will be returned to the vendor. The goal of the proposed model is to determine optimal delivery frequency, review period and production rate by minimizing the joint total cost. A sensitivity analysis is performed to show the impact of the changes of the decision variables on model’s behavior. The result from the sensitivity analysis shows that the joint total cost is sensitive to the changes of defect rate, demand uncertainty and demand rate. 

scholarly journals Effect of Energy and Failure Rate in a Multi-Item Smart Production System

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2958 ◽  
Author(s):  
Mitali Sarkar ◽  
Biswajit Sarkar ◽  
Muhammad Iqbal
Keyword(s):  
Energy Consumption ◽  
Production Rate ◽  
Failure Rate ◽  
Production System ◽  
Optimal Solution ◽  
Development Cost ◽  
Lot Size ◽  
Defective Items ◽  
Unusual Amount ◽  
Control State

To form a smart production system, the effect of energy and machines’ failure rate plays an important role. The main issue is to make a smart production system for complex products that the system may produce several defective items during a long-run production process with an unusual amount of energy consumption. The aim of the model is to obtain the optimum amount of smart lot, the production rate, and the failure rate under the effect of energy. This study contains a multi-item economic imperfect production lot size energy model considering a failure rate as a system design variable under a budget and a space constraint. The model assumes an inspection cost to ensure product’s quality under perfect energy consumption. Failure rate and smart production rate dependent development cost under energy consumption are considered, i.e., lower values of failure rate give higher values of development cost and vice versa under the effect of proper utilization of energy. The manufacturing system moves from in-control state to out-of-control state at a random time. The theory of nonlinear optimization (Kuhn–Tucker method) is employed to solve the model. There is a lemma to obtain the global optimal solution for the model. Two numerical examples, graphical representations, and sensitivity analysis of key parameters are given to illustrate the model.

scholarly journals A Constrained Production System Involving Production Flexibility and Carbon Emissions

Mathematics ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 275 ◽  
Author(s):  
Asif Iqbal Malik ◽  
Byung Soo Kim
Keyword(s):  
Production Rate ◽  
Carbon Emissions ◽  
Production System ◽  
Ghg Emissions ◽  
Real Life ◽  
Lot Size ◽  
Setup Cost ◽  
Defective Items ◽  
Machine Failure ◽  
Decision Variables

The proposed study presents an economic lot size and production rate model for a single vendor and a single buyer setup. This model involves greenhouse gas (GHG) emissions from industrial sources. The carbon emissions in this model are considered as two types: direct emissions and indirect emissions. The production rate affects carbon emissions generation in production, i.e., generally, higher production rates result in more emissions, which is governable in many real-life cases. The production rate also impacts the process reliability and quality. Faster production deteriorates the production system quickly, leading to machine failure and defective items. Such reliability and quality problems increase energy consumptions and supply chain (SC) costs. This paper formulates a vendor-buyer SC model that tackles these issues. It considers two decision-making policies: integrated or centralized as well as decentralized, where the aim is to obtain the optimal values of the decision variables that give the minimum total SC cost. It includes the costs of setup, holding inventory, carbon emissions, order processing, production, reworking, and inspection processes. The decision variables are the production rate, lead time, order quantity, the number of shipments, and the investments for setup cost reduction. In the later sections, this paper compares the numerical outcomes of the two centralized and decentralized policies. It also provides sensitivity analysis and useful insights on the economic and environmental execution of the SC.

scholarly journals Production inventory models for deteiorative items with three levels of production and shortages

2017 ◽  
Vol 27 (4) ◽  
pp. 499-519
Author(s):  
Chickian Krishnamoorthi ◽  
C.K. Sivashankari
Keyword(s):  
Production Rate ◽  
Consumer Satisfaction ◽  
Optimal Solution ◽  
Inventory Model ◽  
Lot Size ◽  
Inventory Models ◽  
Total Cost ◽  
Initial Stage ◽  
Production Inventory ◽  
Holding Cost

In this paper, three level production inventory models for deteriorative items are considered under the variation in production rate. Namely, it is possible that production started at one rate, after some time, switches to another rate. Such a situation is desirable in the sense that by starting at a low rate of production, a large quantum stock of manufacturing items at the initial stage are avoided, leading to reduction in the holding cost. The variation in production rate results in consumer satisfaction and potential profit. Two levels of production inventory models are developed, and the optimum lot size quantity and total cost are derived when the production inventory model without shortages is studied first and a production inventory model with shortages next. An optimal production lot size, which minimizes the total cost, is developed. The optimal solution is derived and a numerical example is provided. The validation of the results in this model was coded in Microsoft Visual Basic 6.0.

scholarly journals Managing a sustainable integrated inventory model for imperfect production process with type one and type two errors

2021 ◽  
Author(s):  
Novrianty Rizky ◽  
Ivan Darma Wangsa ◽  
Wakhid Ahmad Jauhari ◽  
Hui Ming Wee
Keyword(s):  
Lead Time ◽  
Capital Investment ◽  
Item Type ◽  
Inventory Model ◽  
Lot Size ◽  
Setup Cost ◽  
Defective Items ◽  
Defective Item ◽  
Integrated Inventory Model ◽  
Integrated Inventory

Abstract This study develops a sustainable integrated inventory model for controllable lead time with defective items, errors in inspection, and variable lead-time. The research investigates the effect of controlling lead time and capital investment in the setup cost. We assume that the buyer receives a lot size that may contain some defective items with a known defective probability. The buyer’s inspector conducts a 100% quality inspection and may incorrectly classify a non-defective item as a defective item (type one (I) error), or incorrectly classify a defective item as a non-defective item (type two (II) error). The mathematical inventory model considering carbon emission cost is developed, and the solution procedure is designed to derive the optimal solution. Finally, numerical examples and sensitivity analysis are given to illustrate the results.

Residency Training and Hand Surgery Practice Patterns: A National Surgical Quality Improvement Program Database Analysis

2020 ◽  
Author(s):  
James J. Drinane ◽  
Brian Drolet ◽  
Ashit Patel ◽  
Joseph A. Ricci
Keyword(s):  
Quality Improvement ◽  
Residency Training ◽  
Practice Patterns ◽  
Hand Surgery ◽  
Soft Tissue Coverage ◽  
Improvement Program ◽  
Surgical Quality ◽  
Orthopedic Surgeons ◽  
Procedural Volume ◽  
General Surgeons

Abstract Introduction Fellowship-trained hand surgeons may have residency training in either orthopedic, plastic, or general surgery, generating significant variability in education background. To study the effect of different training backgrounds on practice pattern variations, we utilized the NSQIP (National Surgical Quality Improvement Database) database to assess hand surgery volumes and case variety by specialty. Materials and Methods NSQIP years 2008 to 2017 was queried with hand surgery current procedural terminology codes defined by the American Board of Orthopedic Surgery. Procedures were grouped according to type and specialty, and relative rates calculated. Hand society membership data were used to determine if procedural volume for each specialty in each category and overall contribution to the volume of hand surgery performed nationally was distributed in accordance with membership data. Results A total of 145,015 hand surgeries were performed; 13,267 (9.1%) by general surgeons, 28,402 (19.6%) by plastic surgeons, and 103,346 (71.3%) by orthopedic surgeons. Orthopedic surgeons performed significantly more bone, fracture, joint, and tendon cases. General surgeons and plastic surgeons performed higher than expected numbers of soft tissue coverage and cases overall with respective excesses of 183 and 22%. Conclusion Hand surgery is an available fellowship pathway from multiple residencies. Fellowship training does not level the field of real-world practice patterns. Residency training experiences significantly impact practice.

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