Mathematical modeling for a multiproduct manufacturing system featuring postponement, external suppliers, overtime, and scrap

Manufacturing firms operating in today’s competitive global markets must continuously find the appropriate manufacturing scheme and strategies to effectively meet customer needs for various types of quality of merchandise under the constraints of short order lead-time and limited in-house capacity. Inspired by the offering of a decision-making model to aid smooth manufacturers’ operations, this study builds an analytical model to expose the influence of the outsourcing of common parts, postponement policies, overtime options, and random scrapped items on the optimal replenishment decision and various crucial system performance indices of the multiproduct problem. A two-stage fabrication scheme is presented to handle the products’ commonality and the uptime-reduced strategies to satisfy the short amount of time before the due dates of customers’ orders. A screening process helps identify and remove faulty items to ensure the finished lot’s anticipated quality. Mathematical derivation assists us in finding the manufacturing relevant total cost function. The differential calculus helps optimize the cost function and determine the optimal stock-replenishing rotation cycle policy. Lastly, a simulated numerical illustration helps validate our research result’s applicability and demonstrate the model’s capability to disclose the crucial managerial insights and facilitate manufacturing-relevant decision making.

Collective impact of scrap, random breakdown, overtime and discontinuous issuing on batch production planning in a supply-chain environment

This research explores the collective impact of overtime, random breakdown, discontinuous issuing rule, and scrap on batch production planning in a supply-chain environment. In today’s global business environment, manufacturing firms encounter numerous operational challenges. Externally, they must promptly satisfy the customers’ various requests, while internally, they must cautiously manage several inevitable issues in the fabrication process. These issues might be concerned with scrap, random breakdown, etc. Resolving such issues is crucial for meeting the due dates of customers’ orders, adhering to the expected manufacturing schedules, product quality, and minimizing the total fabrication-transportation-inventory costs. The study develops a model to characterize the system’s features mentioned above and assist the manufacturers with batch fabrication planning. The model proposes a solution process with an algorithm seeking an optimal runtime for the system. Additionally, it gives a numerical illustration depicting the collective and individual impacts of these special features on the operating policy and other performance indices. This model and the research findings can facilitate manufacturers’ decision-making for green batch fabrication and enhance competitive advantage.

Inventory Replenishment Policies for Two Successive Generations of Technology Products under Permissible Delay in Payments

In this age of digitalization, when every industry is undergoing technological disruption, there is a big role of digital gadgets and technology products. A key feature of these digital gadgets is the short length of the product life cycle, since the newer and more advanced generations of technologies are developed regularly to replace the earlier conventional technologies. The traditional EOQ models that assume a constant demand cannot be used here. This research paper formulates an inventory optimization model for the multi-generational products under the trade credits and the credit-linked and innovation diffusion dependent demand. The study also performs a numerical illustration of the proposed model, and establishes important dynamics among the key variables. It also performs the sensitivity analysis with the cost of credit and the trade credit period. The paper concludes with the managerial implications for the inventory practitioners and the possible areas of extension for this research in the future.

Neutrino beam driven instability of magnetosonic waves in the presence of obliquemagnetic field and ion-neutral collisional effect in plasmas

The neutrino beam driven instability of fast and slow magnetosonic waves with oblique applied magnetic field in multi-component ion, electron, and neutrino beam plasma is studied. The dissipation effects of ion-neutral collisions are also included in the model. The neutrino and electron interactions through electro-weak force are included. It is found that the dissipation of ion collisions has significant effect on the phase velocity of the wave propagation and growth rate of the neutrino beam driven instability. The analytical expression of the growth rate of the fast and slow magnetosonic waves instability is found under the weak neutrino beam approximation and in the absence of ions and neutrals (atoms) collision effect. The numerical illustration of growth rates of the fast and slow magnetosonic waves are also presented with variations of magnetic field angle, neutrino beam energy, neutrino beam density, magnetic field intensity. It is found that the growth rate of the fast magnetosonic wave is maximum in case of the perpendicular directed magnetic field to the direction of wave propagation, while growth rate of slow magnetosonic wave is minimum in that case. It is also noticed that growth rate of fast magnetosonic wave comes out to be larger (of the order tens) than the slow magnetosonic wave case, which is quite different from earlier published results of Type II core-collapse supernova.

Analysis of Flexible Batch Service Queueing System to Constrict Waiting Time of Customers

When the required number of customers is available in the general bulk service (GBS) queueing system, the server begins service. Otherwise, the server will remain inactive until the number of consumers in the queue reaches that minimum required number. Customers that have already come must wait throughout this time, regardless of their arrival time. In some circumstances, like specimens awaiting testing in a clinical laboratory or perishable commodities awaiting delivery, it is necessary to finish services before the expiration date. It might only be achievable if consumers’ waiting times are kept under control. As a result, the flexible general bulk service (FGBS) rule is developed in this article to provide flexibility in batching. The effectiveness of FGBS implementation has been demonstrated using two examples: a clinical laboratory and a distribution center. To justify the suggested model, a simulation study and numerical illustration are provided.

A COLLECTIVE RESERVING MODEL WITH CLAIM OPENNESS

The present paper introduces a simple aggregated reserving model based on claim count and payment dynamics, which allows for claim closings and re-openings. The modelling starts off from individual Poisson process claim dynamics in discrete time, keeping track of accident year, reporting year and payment delay. This modelling approach is closely related to the one underpinning the so-called double chain-ladder model, and it allows for producing separate reported but not settled and incurred but not reported reserves. Even though the introduction of claim closings and re-openings will produce new types of dependencies, it is possible to use flexible parametrisations in terms of, for example, generalised linear models (GLM) whose parameters can be estimated based on aggregated data using quasi-likelihood theory. Moreover, it is possible to obtain interpretable and explicit moment calculations, as well as having consistency of normalised reserves when the number of contracts tend to infinity. Further, by having access to simple analytic expressions for moments, it is computationally cheap to bootstrap the mean squared error of prediction for reserves. The performance of the model is illustrated using a flexible GLM parametrisation evaluated on non-trivial simulated claims data. This numerical illustration indicates a clear improvement compared with models not taking claim closings and re-openings into account. The results are also seen to be of comparable quality with machine learning models for aggregated data not taking claim openness into account.

A Proposed Method to Evaluate Warehouse Location for 3PL Cold Chain Suppliers in Gulf Countries Using Neutrosophic Fuzzy EDAS

Logistics processes have been analyzed as one of the most critical expense items for companies. Companies that failed to manage their logistics processes well could not reach the desired growth rates, and some even disappeared. Logistics management without process optimizations can be time and money consuming for the companies. Logistics processes significantly influence organizations' efficiency. Logistic professionals should keep the process flow quality at a certain level, and some decision problems should be analyzed and answered well. Location selection of a warehouse is one of the most crucial decision problems of supply chain and logistics management. Alternatives are evaluated in quantitative and qualitative criteria to decide the best location alternative using scientific MCDM techniques. Different scientific methods have been developed and used to solve this problem. As for this study, the aim is to investigate the warehouse location selection of third-party cold chain logistics suppliers. The importance of keeping perishable products under the right conditions increased, since it is realized that cold chain warehousing and transportation prevent the product spoiled. Organizations can save their funds and time by having effective cold chain management. This study's main scope is to give a new scientific perspective for warehouse selection in cold chain logistics. MCDM technique of Interval-Valued Neutrosophic Fuzzy (IVNF) EDAS method has been used to evaluate essential criteria and choose the best option. Critical cities of Gulf Region countries have been considered alternatives in a numerical illustration.

A STRONG CONVERGENCE AND NUMERICAL ILLUSTRATION FOR THE ITERATIVE METHODS TO SOLVE A SPLIT COMMON NULL POINT PROBLEM AND A VARIATIONAL INEQUALITY IN HILBERT SPACES

Trong bài báo này, chúng tôi giới thiệu hai thuật toán lặp để giải bài toán không điểm chung tách và bài toán bất đẳng thức biến phân đơn điệu trong không gian Hilbert. Các bài toán này có nhiều ứng dụng quan trọng trong những lĩnh vực như xử lý tín hiệu, xử lý ảnh, điều khiển tối ưu và nhiều lĩnh vực khác của toán học cũng như trong đời sống. Các phương pháp mà chúng tôi đề xuất dựa trên phương pháp lặp Halper n và phương pháp xấp xỉ mềm đã được áp dụng để giải các bài toán điểm bất động và bất đẳng thức biến phân. Sự hội tụ mạnh của thuật toán đã được chứng minh cùng với một số điều kiện nhất định đặt lên các dãy tham số. Cuối cùng chúng tôi đưa ra một ví dụ số giải bài toán tối ưu trong không gian hữu hạn chiều để minh họa cho sự hội tụ của thuật toán.

Carbon-Trade Price Influence on CarbonRegulation of Tobacco Supply Chain

Carbon emissions exist in all links of tobacco SC, among whichtobacco, acetic acid tow and cigarette production are important links of cigarette carbon emission. Under the background of green economic development, it is very significant to study the coordinated development of economy and environment from the angle of tobacco SC. Carbon-trade is aneffectivechannel to realize reducing carbon emissions by using market mechanism. Take into consideration grandfathering and the goal of carbon regulation, game models of SCwith carbon trading are established. We analyze the influence of three factors including carbon-trade price, decision-making mode, technology emission reduction investment on the degree of carbon regulation and SC profits, the conclusions are verified by numerical illustration. The research shows that: without investment of technology, the three different decision-making modescarbon regulation degreeare the same. In the investment of technology emission reduction, the degree of carbon regulation is the strictest under the centralized decision-making mode while the most relaxed under the retailer led decision-making mode. Different carbon-trade prices have different effects on the investment decisions of three different decision-making modes; technology investment in decentralized decision-making is always conducive to retailer and the total profits.

Robert Torrens on Say's Law and the General Glut

This paper analyzes how Robert Torrens's system of prices is applied to the aggregate economy. His personal interpretation of Say's Law is articulated with a numerical illustration and the Hawkins-Simon conditions to exemplify how the correct supply of the ingredients of capital is presented as a necessary condition for the full clearing of markets. Next, the possible causes of a shortage in effectual demand are discussed. The quantitative illustrations developed by Torrens are carefully reviewed to show how the monetary factors play a crucial role during the general glut, as well as the appropriate policy measures to stabilise the economy. The final comments reflect on the originality of Torrens's theoretical work.