Simple Supply Chain Research Articles

Impact of uncertainty ascribed to defective products on supply chains

ABSTRACT Traditional inventory management has considered when and how much to order against the uncertainty of demand. Although many studies on inventory management have presumed that quality of products received from manufacturers is perfect, defective products would be, in actual, contained in the procurement to retailers. The inclusion of defective products causes the uncertainty in supply. The retailer does not necessarily require being responsible for all the loss by overstock and shortage of products due to the uncertainty ascribed to the inclusion of defective products. The purpose of this paper is to investigate the impact of the uncertainty ascribed to the inclusion of defective products on a supply chain. This paper first has formulated a simple supply chain model with defective products composed of the manufacturer and retailer. The model has made it clear how the uncertainty ascribed to the inclusion of defective products has an impact on the order quantity and respective profits. Then, this paper has discussed a method of assessing a latent loss as a monetary value. Combining contract techniques and game theory, this paper has proposed a contracting method that the manufacturer compensates the retailer for the latent loss to maintain a supply chain partnership.

Frictional product market, supply chains and the impact of government expenditures on private consumption

Standard macroeconomic models predict positive values of the government spending multiplier and a decreasing relationship between private consumption and government expenditures. The latter result is at odds with empirical evidence, suggesting that this negative pattern is either moderate or insignificant. Moreover, there are works indicating that this relationship is positive. The aim of this paper is to rationalize positive reactions of both output and consumption induced by higher government spending. To explain those patterns, I use a theoretical model including two ingredients: search frictions in the product market and simple supply chains. It is shown that, in isolation, these two elements give rise to the standard prediction found in the theoretical literature: an increase in fiscal expenditures crowds out private consumption. However, the interaction of both elements generates two equilibria and one of them features both a positive fiscal multiplier and an increasing relationship between government spending and private consumption.

Thermorheological Behavior of κ-Carrageenan Hydrogels Modified with Xanthan Gum

Hydrocolloids are long-chain biopolymers that can form viscous solutions or gels when dissolved in water. They are employed as rheological modifiers in various manufacturing processes or finished products. Due to its unique gelation properties, animal gelatin is one of the most widely used hydrocolloids, finding applications in several fields such as food, pharmaceutical, and photographic. Nowadays, the challenge of finding valid alternatives to animal products has become a crucial issue, for both ethical and environmental reasons. The aim of this work, is to propose a green hydrocolloidal network, able to reproduce the gelation features of animal gelatin gels. κ-carrageenan gels may be an interesting alternative to gelatin, due to their attractive gelling features. We investigate the thermorheological behavior of κ-carrageenan aqueous solutions at various concentrations, focusing on gel features such as transition temperature and gel strength. To improve the viscoelastic response of such gels, we add a viscosity-enhancing hydrocolloid, i.e., xanthan gum. The results show that the gel strength increases exponentially with xanthan concentration, thus suggesting a synergistic interaction between the two networks. We also study the effect of sucrose on the thermal and mechanical properties of modified gels, finding a marked increase in transition temperatures and gel elasticity. In recent years, three-dimensional (3D) food printing has been extensively studied in the food industry, due to its many advantages, such as customized food design, personalized nutrition, simplified supply chain, and the expansion of available food materials. In view of this growing interest for additive manufacturing, we also study the printability of the complete formulation composed of κ-carrageenan, xanthan gum and sucrose.

An integrated modelling approach for an optimal location of warehouses in the defence industry organisation

Countries’ defence industries are the leading indicator of their global power. The warehouse is the place where the materials are kept until the customer order arrives so that the companies are viable and can respond appropriately to internal/external customer demands. In this regard, warehouse location plays a vital role in the defence industry in terms of storage options with increased flexibility, a simplified supply chain with cost management and optimal positioning according to deployment locations. In this study, the decision on the location of warehouses for logistic support during the warranty period of military vehicles manufactured and supplied to the armed forces by a defence company was made. It is aimed to propose the best solution to a real-life problem with high complexity, containing many data and constraints. In this context, the criteria that are thought to be most relevant to this problem have been determined by taking expert opinions. Having determined the order of importance of the requirements by the analytical hierarchy process (AHP) with the Super Decisions V 2.10, their weights were included as a coefficient of the objective function in the goal programming (GP) model. As a result of solving the GP model using GAMS (general algebraic modelling system), it was decided to select the warehouses that provided the optimal results among the alternative warehouse locations in 9 different locations. Furthermore, to see the impact of changes in criterion weights, sensitivity analysis has also been included. The significance of this research lies within the integrated usage of AHP and GP in the defence industry when determining warehouse locations by the experts’ opinions. With this study, not only a solution strategy was developed, but also a basis for the warehouse location decision in the defence industry projects already signed or to be signed was given.

Simultaneous consideration of relative density, energy consumption, and build time for selective laser melting of Inconel 718: A multi-objective optimization study on process parameter selection

Additive manufacturing (AM) is regarded as sustainability friendly thanks to its significantly reduced production steps and simplified supply chain at the system level, but it is often not energy efficient at the process level. In this study, we propose that the optimization of AM process parameters should not only maximize build quality, but also minimize environmental impact and build time. A multi-objective optimization problem of maximizing relative density (RD), minimizing energy consumption and build time per unit volume (ev and tv respectively) is formulated and solved for selective laser melting (SLM) of Inconel 718 alloy. A high accuracy RD prediction model with R2 of 93.23% is obtained by fitting SLM experiment data from wide ranges of laser power (P), scanning speed (SS), hatch spacing (HS), and layer thickness (LT). The ev and tv models are created considering printing area utilization rate (U) based on laser scanning and powder coating process. The two approaches of Pareto front and global criterion method are adopted for solving the multi-objective optimization problem. It is found that the highest RD of close to 100% can be obtained at the expense of high ev and tv of close to 500 J/mm3 and 0.3 s/mm3, respectively, and about three times ev and tv are needed to increase RD from about 95% to 100% than from 85% to 95%. At the same U level, the solutions obtained from prioritizing ev and tv are consistent, while those from prioritizing RD show smaller process parameter values. The multi-objective optimization formulation provides an enabling tool for industry to obtain high quality SLM-ed parts with improved sustainability and efficiency at the process level. The methodology developed is applicable to selective laser melting of other materials, and such consideration can be readily expanded to other AM processes as well.

How does Cross-regional Supply Chain Function in the Global Auto Manufacturing

This paper presents a study on the inter-regional supply chain which helps company to manage the flow of components among regions of affiliate’s and Joint Ventures. Using a type of mode named as IRF (Inter-Regional Flow), the company will be able to create simplified supply chain network and reduce complexity for operation. Other resulting advantages include centralization of capacity management, utilization of sharing of parts from common and modified supplier tooling, and reduction of logistic and manpower cost for the receiving region in purchasing, manufacturing and supply chain management.

Dissolvable Microneedle Patches to Enable Increased Access to Vaccines against SARS-CoV-2 and Future Pandemic Outbreaks.

Vaccines are an essential component of pandemic preparedness but can be limited due to challenges in production and logistical implementation. While vaccine candidates were rapidly developed against severe acute respiratory syndrome coronavirus 2 (SARS-COV-2), immunization campaigns remain an obstacle to achieving herd immunity. Dissolvable microneedle patches are advantageous for many possible reasons: improved immunogenicity; dose-sparing effects; expected low manufacturing cost; elimination of sharps; reduction of vaccine wastage; no need for reconstitution; simplified supply chain, with reduction of cold chain supply through increased thermostability; ease of use, reducing the need for healthcare providers; and greater acceptability compared to traditional hypodermic injections. When applied to coronavirus disease 2019 (COVID-19) and future pandemic outbreaks, microneedle patches have great potential to improve vaccination globally and save many lives.

Review and analysis of blockchain projects in supply chain management

Abstract Supply chains have become increasingly complex, making it difficult to ensure transparency throughout the whole supply chain. In this context, first approaches came up, adopting the immutable, decentralised, and secure characteristics of the blockchain technology to increase the transparency, security, authenticity, and auditability of assets in supply chains. This paper investigates recent publications combining the blockchain technology and supply chain management and classifies them regarding the complexity to be mapped on the blockchain. As a result, the increase of supply chain transparency is identified as the main objective of recent blockchain projects in supply chain management. Thereby, most of the recent publications deal with simple supply chains and products. The few approaches dealing with complex parts only map sub-areas of supply chains. Currently no example exists which has the aim of increasing the transparency of complex manufacturing supply chains, and which enables the mapping of complex assembly processes, an efficient auditability of all assets, and an implementation of dynamic adjustments.

Impact of additive manufacturing on supply chain elements: a literature review-based study

Additive manufacturing (AM) technologies are advancing and narrowing down their limitations in fields and have dramatically changed the way product is designed, prototyped, manufactured and become part of the supply chain (SC), thus providing customers with wider options. This paper tries to address the impact of AM on different elements of the SC and pursues an inductive research approach. The methodology adopted considers both positive and negative views for comparative studies of AM with traditional one. The proposed research explores the implication of the adoption of AM technologies on the supply chain. The topics range from simple SC issues to legal concerns, marketing strategy about new manufacturing technology, and even in non-business areas to explore the technical attributes. The adoption of AM in the industry is low and there is less academic research available. The study shows that AM affects the conventional manufacturing systems and needs to be upgraded in every stage of the SC, from raw material supply to the final delivery system.

Effects of multiple sterilizations and natural aging on the mechanical behavior of 3D-printed ABS

Three-dimensional printing of functional parts for different applications has increasingly attracted the interest of industries, owing to advantages such as seamless customization, a simplified supply chain, and on-demand production of prototypes. Hence, the mechanical properties of 3D prints subjected to different types of loads and exposed to factors specific to working and storage conditions must be studied. In this context, this study focuses on experimentally investigating the mechanical behavior of 3D-printed acrylonitrile butadiene styrene (ABS) specimens exposed to shelf life and multiple sterilizations, as these conditions are typical for medical instruments in a hospital environment. Tensile and flexural specimens were manufactured using fused deposition modeling (FDM) and were randomly divided into two groups. One group was used for evaluating the medium-term natural aging (shelf life) and as the control group for the sterilized specimens. Specimens in the second group underwent repeated sterilizations. Mechanical tests were performed on specimens from both groups, and comparisons of the results were made across groups and within individual groups. The fracture patterns of sterilized and non-sterilized specimens were characterized using scanning electron microscopy (SEM) and industrial computer tomography (CT) was performed to understand the experimental findings. The results show that natural aging and repeated sterilizations do not influence mechanical performance in terms of stiffness and strength in tension and flexion. However, other properties, such as creep, wear, and fatigue should also be considered with regard to sterilization, depending on the instrument functionality.

Transparency for Multi-Tier Sustainable Supply Chain Management: A Case Study of a Multi-tier Transparency Approach for SSCM in the Automotive Industry

Sustainability in supply chain management (SSCM) has become established in both academia and increasingly in practice. As stakeholders continue to require focal companies (FCs) to take more responsibility for their entire supply chains (SCs), this has led to the development of multi-tier SSCM (MT-SSCM). Much extant research has focused on simple supply chains from certain industries. Recently, a comprehensive traceability for sustainability (TfS) framework has been proposed, which outlines how companies could achieve MT-SSCM through traceability. Our research builds on this and responds to calls for cases from the automotive industry by abductively analysing a multi-tier supply chain (MT-SC) transparency case study. This research analyses a raw material SC that is particularly renowned for sustainability problems—the cobalt supply chain for electric vehicles—and finds that the extant literature has oversimplified the operationalisation of transparency in MT-SSCM. We compare the supply chain maps of the MT-SC before and after an auditing and mapping project to demonstrate the transparency achieved. Our findings identify challenges to the operationalisation of SC transparency and we outline how FCs might set to increase MT-SC transparency for sustainability.

The impact of 3D printing on manufacturer–retailer supply chains

In this paper we consider the impact of 3D printing, or additive manufacturing, on a simple supply chain, consisting of a manufacturer and retailer, that serves stochastic customer demand. 3D printing is a relatively new manufacturing technology that is attracting attention from many firms. However, the impact of 3D printing on operations and firm relationships in a supply chain is relatively unexplored in academic research. A unique aspect of 3D printers is that they can be installed at the retailer in a supply chain, a characteristic that we highlight in our paper since it enables the supply chain to be more responsive to demand. Consequently, 3D printers can be adopted by either the manufacturer or, in a more novel situation, the retailer; we analyze the equilibrium of Stackelberg games in both cases. We characterize the economic and competitive conditions where either firm adopts 3D printing, and show that under either scenario, it is possible for both firms to earn more profit than a benchmark system without 3D printing. We identify and quantify the positive benefits associated with 3D printing, for both firms in a simple supply chain, when either firm adopts this new manufacturing technology. In many cases, the scenario where the manufacturer adopts 3D printing and installs 3D printers at the retailer results in the best profit outcomes for the manufacturer. The retailer’s preference, however, depends on problem parameters. Therefore, supply chain managers should carefully consider the possibility of 3D printing products in their supply chain.

Achieving Economic and Environmental Sustainability: Minimum Transport Quantity, Contracts, and Emissions Regulation

Problem Definition: We study the strategic interactions between a supplier and a retailer under demand uncertainty when the supplier has two options for how to ship a product: (i) road transport, which is expensive, high-emission and flexible, and (ii) rail transport, which is cheap, green, and is constrained by a minimum transport quantity (MTQ). Academic / Practical Relevance: Rail transport has been regarded as one of the most practical ways to increase supply chain sustainability. However, the volume shifted from road to rail has remained modest during the last decades. One of the reasons is that rail transport lacks flexibility in its delivery quantity and often requires an MTQ. Methodology: The supplier and the policymaker prefer rail transport because of the advantages of low cost and low emission. However, the shipment quantity, which is determined by the retailer, may not reach the MTQ. The supplier and the policymaker can design incentives (contracts and emission tax) to encourage the use of rail transport. In this work, we build a game-theoretic model for this setting and investigate the impact of the MTQ on the economic and environmental performance of the supply chain and the effect of a tax on emissions. Results: We find that, although MTQ is operationally constraining and can lead to overproduction, it can be turned into a beneficial factor through proper decisions, which would lead to several merits as follows. (1) The MTQ can significantly improve the efficiency of simple supply chain contracts (e.g., price-only contracts). (2) The MTQ does not hurt the efficiency of coordinating contracts (e.g., buy-back contracts) and can increase the supplier’s Pareto-optimal profit. (3) The MTQ can enable coordinating contracts to achieve a higher supply chain profit and fewer total emissions simultaneously, which is not possible without the MTQ. Moreover, we show that, although it can lead to fewer total emissions, an emission tax is more likely to be ineffective in encouraging the use of the green transport mode when firms use coordinating contracts compared to price-only contracts. Managerial Implications: We provide suggestions to firms on how to make optimal decisions and make the best use of different transport modes when dealing with demand risk. Also, we provide suggestions to policymakers on how to design the proper emission tax to promote green logistics.

The effect of full or partial pricing integration on supply chain management

A previous paper proposed a supply chain model, comprised of a retailer and manufacturer, in which the manufacturer uses product pricing to maximize the profit of the entire supply chain. The increased profits gained from integration are then shared among all the supply chain members. The optimal pricing strategy was shown to be “products on consignment” for sale. The present study extends this simple two-layer supply chain model to a more complicated three-layer model, in which the supply chain comprises not only the retailer and manufacturer, but also an intermediate distributor. In contrast to the previous model, the present model not only considers the role of the distributor, but also the effects of product nonconformance at each facility in the supply chain. The profit function of each facility in the supply chain is established, including the sales revenue, procurement cost, and quality control cost. The investment cost at the retailer to improve the service level is also considered. It is shown that the total profit of the supply chain is maximized when the retailer’s optimal service level is adopted, where this service level is adjusted in accordance with the distributor’s unit sale price. Furthermore, after price integration, the overall profit of the supply chain is found to equal the retailer’s profit. In other words, the total profit of the manufacturer and distributor is equal to zero. Numerical examples are given to illustrate the proposed pricing integration model under different quality environments. The results are contrasted with those obtained using a traditional pricing model, namely the “make up on cost’’ model. Overall, the present results show that the manufacturer is always the winner under partial price integration (i.e., only the retailer and distributor join the integration). Furthermore, partial integration is far less profitable for the retailer and distributor than full integration.

ANALISIS PENGARUH MEKANISME KORDINASI TERHADAP SCHEDULE INSTABILITY DAN TOTAL BIAYA PADA LEVEL MPS DI ENTITAS RANTAI PASOK SEDERHANA DENGAN MEMPERTIMBANGKAN LEAD TIME

Instability in production planning (or better known as schedule instability) is unavoidable. This makes the company companies make various efforts to minimize the level of instability. There are several strategies that are generally used to minimize instability schedules, including freezing, safety stock / buffer. In this study, we will try to use a coordination approach to minimize the consequences of instability schedules in a simple supply chain. The simple supply chain system is the focus of this study consisting of one entrepreneur and one supplier integrated through a coordination mechanism (sharing information relating to order orders). This research will be conducted to study a full factorial experiment (full factorial experiment). A variety of different operational conditions are also considered such as: the uncertainty of financing, the cost structure, and the inventory policy applied by the company to be the part observed in this study. The results of this study, namely through the existence of a coordination mechanism, can reduce the level of schedule instability in each entity both manufacturing and supplier. In addition, through coordination it is also able to eliminate the transfer of risks that manufacturers often make to suppliers in the production planning section, as well as being able to reduce total costs to manufacturing or supplier entities. Through this research, it is expected to provide an understanding in the manufacturing industry of the importance of coordination in the supply chain system.

Making Carbon-Emission Reduction Decisions in Supply Chains Based on Vertical Spillover and Environmental Awareness of Consumers

As the environmental awareness of consumers continues to improve and vertical spillover between up-stream and down-stream enterprises is occurring more and more frequently, firms have to consider the two factors when reducing the emissions. To investigate the influence of vertical spillover and environmental awareness of consumers on the decision-making process and profits realized by the supply chain, a simple two-stage supply chain is established (consisting of one supplier and one manufacturer). Centralized and decentralized decision-making models are compared. In the case of centralized, we find that the manufacturer puts in a greater effort to reduce emissions compared to the supplier. With decentralized decision making, the emission-reduction efforts of both parties depend on the vertical spillover rates and environmental awareness levels of the consumers. As the vertical spillover rates and environmental awareness of consumers improve, the differences in emission-reduction effort and profits in the supply chain under the two decision-making models become larger. Furthermore, the coordination efficiency in the supply chain is lower. The problem of coordination in the supply chain is further investigated using a Nash bargaining model. We find that there is an optimal profit distribution ratio which enables the supply chain to be coordinated.

A Method of Supply Chain Evaluation Based on the Structure of an Information Network

A supply chain is a system consisting of different entities, which add value from the original resources to the final products for customers. Although each entity is indispensable for the construction of a supply chain, the degree of importance of each entity varies depending on the role played in the supply chain. In this paper, we assume that the information produced by the entity that plays a more important role should be referred to more by other entities when making appropriate decisions to effectively operate the entire supply chain. Thus, we developed a method that evaluates the soundness of the supply chain based on the structure of its information network. In the method, the structure of the supply chain information network is expressed in a square matrix A. The eigenvector R of the matrix A is assumed as the rate of its own information referred to by other entities in the supply chain. The value of information produced by each entity is represented as a vector V determined by using AHP. Then, the method evaluates the soundness of the supply chain as the norm between R and V. In addition, a design method to search for the ideal structure of the information network is presented. The effectiveness of the proposed method is examined by using simple supply chain models.

ANALISIS DAMPAK COMPONENT COMMONALITY TERHADAP SCHEDULE INSTABILITY PADA SISTEM RANTAI PASOK SEDERHANA

This study analyzed the impact of component commonality to schedule instability. Analysis was implemented in the use of component commonality (use of same component in different product structures) in a simple supply chain system which is consist of one manufacturer and two suppliers. Different operational conditions were introduced such as: demand uncertainty, product cost structure, product lead time, product structure and inventory policy that company utilized. The simulation results suggested that common component could reduce schedule instability in both manufacturer and suppliers. Furthermore, the results also indicated that suppliers were the more affected entities due to uncertainty rather than manufacturer

Information sharing and the impact of shutdown policy in a supply chain with market disruption risk in the social media era

This paper investigates the information sharing issue in a simple supply chain with one manufacturer and one retailer. The market demand might be subject to disruption, but the retailer can get access to some signals from social media platforms to better forecast the market state (regular or disrupted) even though the signals might be not fully reliable. Different from the traditional information sharing literature, we incorporate the shutdown policy into our model. We first characterize the equilibrium outcomes under both with- and without-information sharing cases and then examine the players’ preferences over information sharing or not. It is shown that when the level of information reliability is relatively low, the manufacturer prefers the information sharing cases, whereas the retailer prefers the no-sharing case, and information sharing does harm to the whole channel. In addition, our results show that as the level of information reliability increases, the manufacturer benefits more but the retailer and the whole channel lose more from information sharing. Contrary to the conventional wisdom, when the level of information reliability falls into an intermediary interval, the retailer will have an incentive to share information, and information sharing will benefit the manufacturer and the whole supply chain. However, the benefits from information sharing decrease as the level of information reliability increases. When the level of information reliability is sufficiently high, both firms are indifferent between the information sharing and no-sharing cases. Additionally, the incorporation of the shutdown policy has important implications for the information sharing issue, and thus, the policy should not be overlooked.

Managing supply chain risks and delays in construction project

PurposeThe purpose of this paper is to investigate models and methods for managing supply chain risks and delays in construction projects.Design/methodology/approachThe study mainly employs quantitative analysis in order to identify disruptions in construction supply chains. It also uses paradigms of simulation modeling, which are suitable for risk assessment and management. Both qualitative and quantitative data were collected through a literature review and details of specific construction projects, respectively. A dynamic modeling method was used, and the model was provided with an event-based simulation. Simulation modeling was used to measure the performance of the system.FindingsThe study shows the benefits of applying the dynamic modeling method to a construction project. Using event-based simulation, it was found that construction delays influence both the magnitude and the probability of disruption. This method contributes to the existing theoretical foundations of risk management practices, since it also considers the time factor. This method supplements the Monte Carlo statistical simulation method, which has no time representation. Using empirical analysis, the study proposes increasing the safety stock of construction materials at the distribution center, so as to mitigate risks in the construction supply chain.Research limitations/implicationsThe research considers a single case of a hypothetical construction project. The simulation models represent a simple supply chain with only one supplier. The calculations are based on the current economic scenario, which will of course change over time.Practical implicationsThe outcomes of the study show that the introduction of a safety stock of construction materials at the distribution center can prevent supply chain disruption. Since the consideration of risks at all stages of construction supply chain is essential to investors, entrepreneurs and regulatory bodies, the adoption of new approaches for their management during strategic planning of the investment projects is essential.Originality/valueThis dynamic modeling method is used in combination with the Monte Carlo simulation, thus, providing an explicit cause-and-effect dependency over time, as well as a distributed value of outcomes.