Inventory, logistics, and transportation
Amin Farahbakhsh; Amir Saman Kheirkhah
Abstract
The inventory routing problem arises from the combination of the vehicle routing problem and the vendor-managed inventory problem. In this paper, we present a mathematical model and a novel genetic algorithm for solving the multi-period inventory routing problem. The objective is to supply products to ...
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The inventory routing problem arises from the combination of the vehicle routing problem and the vendor-managed inventory problem. In this paper, we present a mathematical model and a novel genetic algorithm for solving the multi-period inventory routing problem. The objective is to supply products to scattered customers within a given time horizon while managing customer inventories to avoid shortages and minimize total inventory and transportation costs. To represent solutions for this problem, we introduce a new chromosomal structure. This structure offers simplicity in encoding and decoding solutions, maintains feasibility after crossover and mutation operations, addresses both routing and inventory management in a single step, and consolidates information about each solution method comprehensively. The algorithm parameters, including crossover and mutation rates, population size, number of iterations, and selection pressure, are fine-tuned using the Taguchi method. To assess algorithm efficiency, we utilize standard instances from the literature. Our results demonstrate that the proposed algorithm performs favorably compared to previous approaches.
Inventory, logistics, and transportation
Kehinde Adegbola; Abdulrakib Abdulrahman
Abstract
Consignment stocks agreement had been very useful in inventory control. The benefit ranges from improved cash flow, reduced risk level, savings on investment, reduced ownership cost, low inventory carrying cost and regular restocking to mention few. Also, small batch delivery is an effective strategy ...
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Consignment stocks agreement had been very useful in inventory control. The benefit ranges from improved cash flow, reduced risk level, savings on investment, reduced ownership cost, low inventory carrying cost and regular restocking to mention few. Also, small batch delivery is an effective strategy for launching a product since it enables a business to assess the market and validate the product before committing to a large production run. In this paper, we combined small batch delivery and consignment stock policy by considering a supply chain setting where a vendor fulfilled the shipment requirement of each buyer sequentially in a single production set up. To achieve this, and as against the equal size shipments policy assumed in literature for different buyers, the vendor sends a smaller shipment first as early entry, followed by n equal shipments. These n shipments are proportionately increased according to the vendor rate of production to each buyer’s demand rate. A mathematical cost function is developed to reduce the overall cost of the integrated supply chain system through the optimal cycle time and the optimal numbers of shipments to be delivered to each buyer. Numerical example is given using data from an existing literature, results were compared, and the new distribution policy gives better financial savings in terms of cost over the equal shipment policy assumed in literature. Sensitivity analyses were performed on key parameters to evaluate the robustness of the model.
Inventory, logistics, and transportation
Filscha Nurprihatin; Metta Gotami; Glisina Dwinoor Rembulan
Abstract
This paper discusses the inefficient and inaccurate raw material supply at a food company which results in a backlog. This means the overstock occurs so that the improvement of inventory control needs to be done. ABC classification is firstly utilized as input for Material Requirements Planning (MRP). ...
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This paper discusses the inefficient and inaccurate raw material supply at a food company which results in a backlog. This means the overstock occurs so that the improvement of inventory control needs to be done. ABC classification is firstly utilized as input for Material Requirements Planning (MRP). This paper focuses on four products which are classified into A class. Then, this paper discusses the Triple Exponential Smoothing (TES) as the forecasting method. Aggregate planning is also conducted for better production planning. The results of aggregate planning provide solutions to increase the workforce to balance production capacity by the number of demands. Squared Coefficient of Variation (SCV) calculations indicates the demand follows a static pattern. Therefore, the appropriate lot sizing method is the Economic Order Quantity (EOQ) to carry out the production needs. Finally, this paper uses capacity planning using Rough-Cut Capacity Planning (RCCP) and Capacity Requirement Planning (CRP) methods. As a result, the capacity meets the Master Production Schedule (MPS) as well as MRP and they are feasible to be implemented.
Inventory, logistics, and transportation
H. Nozari; M. Fallah; A. Szmelter-Jarosz
Abstract
The green smart supply chain is a phenomenon that has emerged as a result of the development of sustainable and smart business and information technology trends. Sustainable and green supply chains are an innovative phenomenon that uses information technology to improve the quality of activities in operating ...
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The green smart supply chain is a phenomenon that has emerged as a result of the development of sustainable and smart business and information technology trends. Sustainable and green supply chains are an innovative phenomenon that uses information technology to improve the quality of activities in operating areas. In order to ensure that activities are adapted to social and environmental needs. In this regard, the Internet of Things is one of the most important components of technology infrastructure for smart. For this purpose, in this research, a framework for implementing a green IoT-based supply chain is presented. This framework is based on the four-stage architecture of the Internet of Things and has been created by emphasizing the literature and the interaction and review of the opinions of active experts in this field. This framework illustrates the direct relationship between data generation and how it interacts with the sectors affected by environmental sustainability and outlines a clear pathway for sustainable and green decision-making in the supply chain. This framework has been endorsed by experts in the supply chain field and can pave the way for effective implementation of the green supply chain with an emphasis on technology in manufacturing organizations.
Inventory, logistics, and transportation
U. G. Chike; M. S. Stephens
Abstract
The aim of this study is to examine customers’ satisfaction with the level of service in Murtala Muhammed International Airport (MMIA), Lagos, Nigeria; so as to identify the service attributes requiring managerial attention in the airport. The study evaluated twenty eight service attributes in ...
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The aim of this study is to examine customers’ satisfaction with the level of service in Murtala Muhammed International Airport (MMIA), Lagos, Nigeria; so as to identify the service attributes requiring managerial attention in the airport. The study evaluated twenty eight service attributes in order to assess passengers’ expectations and satisfaction. Survey was conducted and four hundred copies of questionnaire were administered to the study population. The data was analyzed using descriptive statistics, GAP analysis and t-test statistics. The results revealed that the twenty eight service attributes showed a significant difference (significant level ≤ 0.05) between male and female respondents’ perceptions. Although, the expectations of these service attributes were high yet their satisfaction level was low. This suggests that customers’ satisfaction with MMIA, Lagos decreased. Thus, the service attributes that are of high expectation to passengers using the airport but performing poorly with low satisfaction level include “Speed of bags delivery service”, “Flight are screens”, “Comfort of waiting” and “Phone/Internet/IT facilities.” The aforementioned service attributes are those that require managerial attention in the airport. Hence, major improvement is needed here so as to enhance customers’ satisfaction.
Inventory, logistics, and transportation
Ch. G. Udoka
Abstract
The aim of this study is to examine the impact of passengers’ traffic on Exchange Rate (ER) and economic growth in Nigerian aviation industry. This study adopts an ex-post facto research design, a systematic empirical inquiry in order to carry out the research. Secondary data was obtained from ...
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The aim of this study is to examine the impact of passengers’ traffic on Exchange Rate (ER) and economic growth in Nigerian aviation industry. This study adopts an ex-post facto research design, a systematic empirical inquiry in order to carry out the research. Secondary data was obtained from the Federal Airports Authority of Nigeria (FAAN) and National Bureau of Statistics (NBS). The study employed trend analysis on the time series data and regression analysis to explore the cause-and-effect relationship among variables. The result showed that the trend of exchange rate and aviation contribution to Gross Domestic Product (GDP) have been on increase over certain periods. Hence, the linear trend line shows a steady increase in the pattern of exchange rate and economic growth over the sample period of 2000 to 2020 with R-squared values of 0.714 and 0.824, respectively indicating a good fit of the line to the data. The regression analysis revealed that Passengers’ Traffic (PT) has a positive impact on ER and economic growth. Thus, with a T-statistic of 3.296 and probability of 0.004, it indicates a statistically significant effect on the dependent variable (i.e. Exchange Rate). Also, with a T-statistic of 6.119 and probability of 0.000, it indicates a statistically significant impact on the dependent variable (i.e. Economic Growth).
Inventory, logistics, and transportation
A. Adetayo Adeniran; K. Olufunto Adedotun
Abstract
Trend analysis of domestic air travel demand in Nigeria was examined based on yearly passenger demand from 2010 to 2017. Ordinary Least Square (OLS) regression was used to forecast for twelve years (2018 to 2030) demand for domestic air passenger travel in Nigeria. The demand for domestic air passenger ...
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Trend analysis of domestic air travel demand in Nigeria was examined based on yearly passenger demand from 2010 to 2017. Ordinary Least Square (OLS) regression was used to forecast for twelve years (2018 to 2030) demand for domestic air passenger travel in Nigeria. The demand for domestic air passenger in Nigeria from year 2010 to 2017 was compared with the forecast. There seems to be periods of fluctuations in the demand for domestic air passenger travel in Nigeria from year 2010 to 2017 which are expected to have effect on the forecast of domestic air travel. Calculation and computation reveals that the coefficient of determination R2 is 0.203 which signifies a high error term such that the explanation level is very low; hence the prediction or forecast is unreliable. Despite the decline in the forecast of domestic air passenger demand in the future, and the fact that the forecast is unreliable, hence inconclusive as shown from the coefficient of determination, government agencies should be sensitive to the forecast and try to adopt new policies and strategies that will improve the demand for domestic air passenger travel in Nigeria.
Inventory, logistics, and transportation
H. Farrokhi-Asl; R. Tavakkoli-Moghaddam
Abstract
This paper is an extension of the well-known vehicle routing problem (VRP) consisting of two stages. The first and second stages deal with the vehicle routing and transportation problems, respectively. Waste collection is one of the applications of the considered problem in a real world situation. A ...
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This paper is an extension of the well-known vehicle routing problem (VRP) consisting of two stages. The first and second stages deal with the vehicle routing and transportation problems, respectively. Waste collection is one of the applications of the considered problem in a real world situation. A new mathematical model for this type of the problem is presented that minimizes the waste collection cost and decreases the risk posed to the environment for hazardous wastes transportation simultaneously. According to the NP-hard nature of the problem, a new multi-objective hybrid cultural and genetic algorithm (MOHCG) is proposed to obtain Pareto solutions. A straightforward representation for coding the given model is proposed to help us in reducing the computational time. To validate the proposed algorithm, a number of test problems are conducted and the obtained results are compared with the results of the well-known multi-objective evolutionary algorithm, namely non-dominated sorting genetic algorithm (NSGA-II), with respect to some comparison metrics. Finally, the conclusion is provided.
