scholarly journals Does the Autonomation Policy Really Help in a Smart Production System for Controlling Defective Production?

Mathematics ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 1142 ◽  
Author(s):  
Mitali Sarkar ◽  
Li Pan ◽  
Bikash Koli Dey ◽  
Biswajit Sarkar
Keyword(s):  
Production System ◽  
Capital Investment ◽  
Single Type ◽  
Main Theme ◽  
Total System ◽  
Production Rates ◽  
Setup Cost ◽  
Defective Items ◽  
Long Run ◽  
Imperfect Items

This study explains about a serial smart production system where a single-type of product is produced. This system uses an unequally sized batch policy in subsequent stages. The setup cost is not always deterministic, it can be controllable and reduced by increasing the capital investment cost, and that the production rates in the system may vary within given limits across batches of shipments. Furthermore, as imperfect items are produced in long-run system, to clean the imperfectness autonomation policy is adopted for inspection, which make the process smarter. The shipment lot sizes of the deliveries are unequal and variable. In long-run production system, defective items are produced in “out-of-control” state. In this model, the defect rate is random with a uniform distribution which is clean from the system by autonomation. In addition, in the remanufacturing process, it is assuming that all defective products are repaired, and no defective products are scrapped. The main theme of developing this model is to determine the number of shipments and the optimal production lot size to adjust the production rates and decrease the total system cost under a reduced setup cost by considering the discrete investment and make a serial smart production system. A solution procedure along with an advanced algorithm was proposed for solving the model. Numerical examples with some graphical representations are provided to validate the model.

scholarly journals A Single-Stage Manufacturing Model with Imperfect Items, Inspections, Rework, and Planned Backorders

Mathematics ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 446 ◽  
Author(s):  
Chang Wook Kang ◽  
Misbah Ullah ◽  
Mitali Sarkar ◽  
Muhammad Omair ◽  
Biswajit Sarkar
Keyword(s):  
Production System ◽  
Single Stage ◽  
Order Quantity ◽  
Lot Size ◽  
Defective Items ◽  
Long Run ◽  
Proposed Model ◽  
Imperfect Items ◽  
Inspection Process ◽  
Inspection Station

Each industry prefers to sell perfect products in order to maintain its brand image. However, due to a long-run single-stage production system, the industry generally obtains obstacles. To solve this issue, a single-stage manufacturing model is formulated to make a perfect production system without defective items. For this, the industry decides to stop selling any products until whole products are ready to fulfill the order quantity. Furthermore, manufacturing managers prefer product qualification from the inspection station especially when processes are imperfect. The purpose of the proposed manufacturing model considers that the customer demands are not fulfilled during the production phase due to imperfection in the process, however customers are satisfied either at the end of the inspection process or after reworking the imperfect products. Rework operation, inspection process, and planned backordering are incorporated in the proposed model. An analytical approach is utilized to optimize the lot size and planned backorder quantities based on the minimum average cost. Numerical examples are used to illustrate and compare the proposed model with previously developed models. The proposed model is considered more beneficial in comparison with the existing models as it incorporates imperfection, rework, inspection rate, and planned backorders.

scholarly journals An EPQ inventory model considering an imperfect production system with probabilistic demand and collaborative approach

2019 ◽  
Vol 17 (2) ◽  
pp. 282-304
Author(s):  
Katherinne Salas-Navarro ◽  
Jaime Acevedo-Chedid ◽  
Gina Mora Árquez ◽  
Whady F. Florez ◽  
Holman Ospina-Mateus ◽  
...  
Keyword(s):  
Supply Chain ◽  
Production System ◽  
Inventory Model ◽  
Collaborative Approach ◽  
Lot Size ◽  
Defective Items ◽  
Content Type ◽  
Imperfect Production ◽  
Imperfect Items ◽  
Exponential Probability

Purpose The purpose of this paper is to propose an economic production quantity (EPQ) inventory model considering imperfect items and probabilistic demand for a two-echelon supply chain. The production process is imperfect and the imperfect quality items are removed from the lot size. The demand rate of the inventory system is random and follows an exponential probability density function and the demand of the retailers is depending on the initiatives of the sales team. Design/methodology/approach Two approaches are examined. In the non-collaborative approach, any member of the supply chain can be the leader and takes decisions to optimize the profits, and in the collaborative system, all members make joint decisions about the production, supply, sales and inventory to optimize the profits of the supply chain members. The calculus approach is applied to find the maximum profit related to the members of the supply chain. Findings A numerical example is presented to illustrate the performance of the EPQ model. The results show that collaborative approach generates greater profits to the supply chain and the market’s demand represents the variable behavior and uncertainty that is generated in the replenishment of a supply chain. Originality/value The new and major contributions of this research are: the inventory model considers demand for products is random variable which follows an exponential probability distribution function and it also depends on the initiatives of sales teams, the imperfect production system generates defective items, different cycle time are considered in manufacturer and retailers and collaborative and non-collaborative approaches are also studied.

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 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.

scholarly journals Community structure and carbonate production of a temperate rhodolith bank from Arvoredo Island, southern Brazil

2004 ◽  
Vol 52 (3-4) ◽  
pp. 207-224 ◽  
Author(s):  
Douglas F. M. Gherardi
Keyword(s):  
Community Structure ◽  
Coralline Algae ◽  
Carbonate Content ◽  
Production Rates ◽  
Percentage Cover ◽  
Coralline Red Algae ◽  
Carbonate Production ◽  
Random Dispersal ◽  
Long Run ◽  
Main Bank

A small (100,000 m²) rhodolith bank located at the Arvoredo Marine Biological Reserve (Santa Catarina, Brazil) has been surveyed to determine the main bank components, the community structure, and carbonate production rates. Data from five photographic transects perpendicular to Arvoredo Island shore were complemented with sediment samples and shallow cores, all collected by scuba diving. The main bank component is the unattached, nongeniculate, coralline red algae Lithophyllum sp., used as substrate by the zoanthid Zoanthus sp. Percentage cover of living and dead coralline algae, zoanthids and sediment patches account for nearly 98% of the investigated area. Classification and ordination of samples showed that differences in the proportion of live and dead thalli of Lithophyllum sp. determine the relative abundances of zoanthids. Results also indicate that similarity of samples is high and community gradients are subtle. Significant differences in percentage cover along transects are concentrated in the central portion of the bank. Low carbonate content of sediments from deeper samples suggests low rates of recruitment and dispersal of coralline algae via fragmentation. However, carbonate production of Lithophyllum sp ranging from 55-136.3 g m-2 yr-1 agrees with production rates reported for other temperate settings. In the long run, rhodolith density at Arvoredo Is. is likely to be dependent upon random dispersal of spores and/or fragments from other source areas.

MODELING OF ENVIRONMENTAL ADAPTATION: AMENITY VERSUS PRODUCTIVITY AND MODERNIZATION

2013 ◽  
Vol 04 (02) ◽  
pp. 1350006 ◽  
Author(s):  
NATALI HRITONENKO ◽  
YURI YATSENKO
Keyword(s):  
Climate Change ◽  
Capital Investment ◽  
Environmental Adaptation ◽  
Negative Consequences ◽  
Adaptation Measures ◽  
Long Run ◽  
Aggregated Model ◽  
Total Productivity ◽  
Adaptation Policies ◽  
Adaptation Investments

We develop an aggregated model to study rational environmental adaptation policies that compensate negative consequences of climate change. The model distinguishes three categories of adaptation measures that (a) compensate the decrease of environmental amenity value, (b) compensate the decrease of total productivity, (c) develop and introduce new hazard-protected capital and technology. We analyze the optimal balance among consumption, capital investment, and different categories of adaptation investments under exogenous climate change. It appears that the climate change damage and subsequent adaptation do not lead to a higher level of capital modernization in the long run as compared to the benchmark case with no climate change. A synergism between productivity-related and amenity-related adaptation activities arises because the productivity-related adaptation positively impacts the economy and creates better possibilities for the amenity adaptation.

scholarly journals Optimal taxation with unobservable investment in human capital

2019 ◽  
Vol 72 (2) ◽  
pp. 501-516 ◽  
Author(s):  
Catarina Reis
Keyword(s):  
Human Capital ◽  
Capital Accumulation ◽  
Optimal Taxation ◽  
Capital Investment ◽  
Physical Capital ◽  
Income Taxes ◽  
Long Run ◽  
Positive Rate ◽  
The Government ◽  
Physical Capital Accumulation

Abstract In a Ramsey model of optimal taxation, if human capital investment can be observed separately from consumption, it is optimal not to distort human or physical capital accumulation in the long run, and only labour income taxes should be used. However, in reality the government can’t always distinguish between investment in human capital and pure consumption, so a tax on labour or consumption will necessarily tax human capital. We find that when investment in human capital is unobservable, the optimal policy is to tax human capital at a positive rate, even in the long run. Whether physical capital should be taxed or not depends on its degree of complementarity with human capital versus labour.

scholarly journals A multi-item batch fabrication problem featuring delayed product differentiation, outsourcing, and quality assurance

2021 ◽  
pp. 63-78 ◽  
Author(s):  
Yuan-Shyi Peter Chiu ◽  
Huei-Hsin Chang ◽  
Tiffany Chiu ◽  
Singa Wang Chiu
Keyword(s):  
Quality Assurance ◽  
Cycle Time ◽  
Optimization Methods ◽  
Total System ◽  
Managerial Decision ◽  
Defective Items ◽  
Time Solution ◽  
Batch Fabrication ◽  
The Individual ◽  
Collective Influence

Variety, quality, and rapid response are becoming a trend in customer requirements in the contemporary competitive markets. Thus, an increasing number of manufacturers are frequently seeking alternatives such as redesigning their fabrication scheme and outsourcing strategy to meet the client’s expectations effectively with minimum operating costs and limited in-house capacity. Inspired by the potential benefits of delay differentiation, outsourcing, and quality assurance policies in the multi-item production planning, this study explores a single-machine two-stage multi-item batch fabrication problem considering the abovementioned features. Stage one is the fabrication of all the required common parts, and stage two is manufacturing the end products. A predetermined portion of common parts is supplied by an external contractor to reduce the uptime of stage one. Both stages have imperfect in-house production processes. The defective items produced are identified, and they are either reworked or removed to ensure the quality of the finished batch. We develop a model to depict the problem explicitly. Modeling, formulation, derivation, and optimization methods assist us in deriving a cost-minimized cycle time solution. Moreover, the proposed model can analyze and expose the diverse features of the problem to help managerial decision-making. An example of this is the individual/ collective influence of postponement, outsourcing, and quality reassurance policies on the optimal cycle time solution, utilization, uptime of each stage, total system cost, and individual cost contributors.

Hotel and Dependency Costs of Residents in Old People's Homes

1978 ◽  
Vol 7 (1) ◽  
pp. 1-22 ◽  
Author(s):  
Bleddyn Davies ◽  
Martin R. J. Knapp
Keyword(s):  
Residential Care ◽  
Capital Investment ◽  
Self Care ◽  
Marginal Costs ◽  
Unit Costs ◽  
Long Run ◽  
Average Unit ◽  
Short Run ◽  
The Cost ◽  
Old People's Homes

AbstractA comparison of costs to the organization of alternative forms of care requires estimates for similar types of client. The degree of dependency is the main characteristic in which comparability is necessary with regard to services for the aged. This paper presents estimates of the costs incurred in providing residential care for clients of four degrees of incapacity for self-care – the capacity implicit in Bevan's residential hotel model of the old people's home, and three progressively more severe states of dependency. The estimates are for two cost concepts – average (unit) costs and marginal costs (the cost of caring for an additional person). The paper also estimates both long-run costs (costs that it is appropriate to take into account in decisions in which capital investment in new plant is being considered), and short-run costs (costs that it is appropriate to consider when the issue is the allocation of existing capacity between client groups). It also examines the consequences of the size of the home with regard to costs. Inter alia the paper shows:(a) that the size of home beyond which costs do not fall with scale provides for as many as fifty places (equivalent to an average daily census of forty-six residents); and(b) that, although the dependency components of costs are much smaller than the hotel components, dependency costs are large enough for it to be important to base comparisons of alternative forms of care on estimates of costs for clients which are comparable with respect to dependency.

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