ABC classification of spare parts considering costs and service

[EN] This paper focuses on the multi-item problem where it is necessary to reach an overall stock availability of the spare parts while minimising involved costs. Over the last years, a number of authors have proposed a variety of approaches and provided different rules in order to classify items in ABC classes. An additional optimisation has to be performed in order to minimise the inventory cost while fulfilling a target service level. The proposed approach focuses on the characteristics of spare parts and optimises the inventory cost subject to the overall target fill rate by means of a closed form formula for calculating the fill rate of every item independently. This new method is validated with a dataset of spare parts of an airline company and clearly outperforms the alternative methods in terms of inventory cost reduction and ease of calculation. Extensions of our results are also indicated.S244255223-

Maritime Spare Parts Management: Current State-of-the-Art

Having the right spare part at the right time to the right place for ship maintenance to the minimal possible costs is an exigent management problem that maritime shipping companies face. This is especially challenging in bulk shipping where routes are not fixed, but subsequent port calls depend on spot market dynamics. Thus, spare parts allocation ahead in time is limited, but possible if failures rates of ship components and their timing can be foreseen, so that spare parts can be allocated to hedge against the risk of long waiting times and thus ship downtimes. Thus, monitoring the condition of components key to the ships performance is essential to the task. This can enable companies to significantly reduce operational costs of their fleet leading to a competitive advantage in a highly volatile market regarding demand and demand-driven freight rates. However, shipping companies seem far away from applying such methods due to various challenges ranging from data gathering and cultivating an understanding of data quality needs, adaptation to move from preventive towards predictive and condition-based monitoring, and the introduction and application of decision support tools for sourcing, spare parts allocation, and inventory management. In this paper, we investigate the current state of the art of maintenance and related spare parts logistics management for maritime shipping and discuss the application of methods to the bulk carriage market. We add practical knowledge from case companies and discuss how challenges can be overcome in providing guidelines for companies

Development of a Heuristics for a Criteria Based Planning of Pallet Storage Systems

Reproducible and quantitative reasoning as the foundation for high-quality planning processes evolves to be key to achieve high quality of speed for logistical processes. This article strives to fulfill this demand by developing a coherent heuristics for the planning of pallet storage systems. The heuristics uses quantitative approaches provided by the available literature. In case of nonexistent sources, the missing components are developed and integrated. To be applicable in an industrial environment, the comparison and assessment of the created implementation alternatives is mainly monetary based. The heuristics follows a modular structure to achieve adaptability and extensibility. It explicitly does not intend to replace a human designer but to support him during the creation and assessment of high-quality design alternatives. A concluding case study evaluates the practical applicability of the heuristics and its created solutions. The review of the heuristics turns out to be positive. As a consequence, extension and improvement tasks are proposed

SKU classification: A literature review and conceptual framework

Purpose - Stock keeping unit (SKU) classifications are widely used in the field of production and operations management. Although many theoretical and practical examples of classifications exist, there are no overviews of the current literature, and general guidelines are lacking with respect to method selection for classifying SKUs. The purpose of this paper is to systematically synthesise the earlier work in this area, and to conceptualise and discuss the factors that influence the choice of a specific SKU classification. Design/methodology/approach - The paper structurally reviews existing contributions and synthesises these into a conceptual framework for SKU classification. Findings - How SKUs are classified depends on the classification aim, the context and the method that is chosen. In total, three main production and operations management aims were found: inventory management, forecasting and production strategy. Within the method three decisions are identified to come to a classification: the characteristics, the classification technique and the operationalisation of the classes. Research limitations/implications - Drawing on the literature survey, the authors conclude with a conceptual framework describing the factors that influence SKU classification. Further research could use this framework to develop guidelines for real-life applications. Practical implications Examples from a variety of industries and general directions are provided which managers could use to develop their own SKU classification. Originality/value - The paper aims to advance the literature on SKU classification from the level of individual examples to a conceptual level and provides directions on how to develop a SKU classification

Multi-item Inventory Problem: Literature Review and a Proposal for Practitioners

[EN] Inventory managers have to assign an inventory policy to each item seeking to satisfy a required global service level with the lowest inventory cost. This paper reviews the existing literature and, based on current research, the most appropriate options are proposed to be used by practitioners.[ES] Los gestores de inventario tienen que asignar una política de inventario a cada artículo con el fin de satisfacer un nivel de servicio global requerido con el menor coste de inventario. En el presente documento se examina la bibliografía existente y, sobre la base de las investigaciones actuales, se proponen las opciones más apropiadas para su utilización práctica.Cardós, M.; De-La-Fuente-Aragón, M.; Ros-Mcdonnell, L. (2021). Multi-item Inventory Problem: Literature Review and a Proposal for Practitioners. Direccion y Organizacion. 74:67-80. https://doi.org/10.37610/dyo.v0i74.603S67807

Evaluating Resident and Client Satisfaction in Acorn of London\u27s Housing

Acorn of London is a housing company that provides private housing to many university students traveling and staying within London. The goal of this project was to work with Acorn, its clients, and residents to provide Acorn with recommendations on how to improve client satisfaction. By surveying residents in Acorn’s properties and interviewing clients affiliated with universities who book for large student groups, we were able to determine Acorn’s strengths and areas it could improve upon. We recommend Acorn make improvements to the flat turnover process, improvements to its student orientation, and renovate its Crawford Passage and Baker’s Row flats. Additionally, we recommend Acorn introduce a client affairs position and implement a digital feedback survey for future use

Stokastik envanter model kullanılarak iş makinelerinin onarımında kullanılan kritik yedek parçalar için envanter yönetim sistemi oluşturulması (Building inventory management system by using stochastic inventory model for critical spare parts used for maintenance of construction machines)

Bu çalışmada, iş makinelerinin bakım onarım deposu için stokastik envanter modeli oluşturulmuştur. Bu model ile, iş makinelerinin onarımında kullanılan kritik yedek parçalara ait envanter yönetimi yapılmaktadır. Oluşturulan model, lineer olmayan stokastik bir tam sayı optimizasyon modelidir. Modelin hedefi, envanter maliyetlerini asgariye indirmek için yedek parçalara ait stok parametrelerini ve yeniden sipariş noktasını belirlemektir. Aynı zamanda kritik yedek parçaların envanterde bulunabilirliği de artırılmaktadır. Modelde, sipariş sıklığı ve servis düzeyi kısıtları da göz önünde bulundurulmuştur. Çözüm metodu olarak geliştirilmiş ABC analizini içeren ve elektronik tablolarda kolayca uygulanabilen sezgisel (heuristic) bir yöntem önerilmiştir. Son olarak, önerilen model ile bir uygulama ve maliyet analizi yapılmış ve mevcut durumdaki ile modelde önerilen optimum envanter düzeyindeki maliyetlerin karşılaştırılması yapılmıştır. Model kullanımı maliyetlerde % 5’in üzerinde bir azalma sağlamaktadır

Risk-Based Decision Making Model for the Selection of Flood Mitigation Alternatives

In recent years, there has been a noticeable increase in the frequency of natural disasters such as wildfires, hurricanes and flooding, resulting in big economic, environmental, and social impacts. In the case of flood events, impacts such as community anxiety, loss of life, water pollution, and contamination of agricultural land have been found to be equally, if not more important, than the economic impacts of such events. Nevertheless, the literature shows that flood risk assessment studies incorporating economic, environmental, and societal impacts are limited. In addition, flood mitigation measures are typically compared focusing on economic criteria and not considering stakeholders or the implementation characteristics of the flood mitigation alternatives. This study proposes a holistic framework for watershed flood management that considers economic, social, environmental, and implementation criteria for selecting among flood mitigation alternatives. First, a spatial flood risk assessment framework capable of integrating economic, social, and environmental impacts is introduced in order to assess the possible losses and risks within the communities of a watershed. The risk assessment uses HAZUS software from the Federal Emergency Management Agency (FEMA) and is executed for five different return periods. Second, in order to select from multiple mitigation alternatives, a Decision-Making Models (DMM) is proposed. The first model uses the results from the risk assessment and the mitigation alternatives are evaluated using a Monte Carlo Simulation and probabilistic optimization. The second DMM model incorporates stakeholders characteristics and opinions using stakeholder theory, network analysis, and the Analytical Hierarchical Process (AHP). Two surveys were developed and deployed to public officials of agencies involved in the planning and implementation of flood mitigation alternatives and to the community, respectively. Along with this information, technical aspects of the flood mitigations alternatives are used as implementation criteria. Three alternatives were evaluated in the decision analysis: (1) no action, (2) flood warning system, and (3) levee. The framework is demonstrated with the case study of the Upper Río Grande of Loíza Watershed in the Commonwealth of Puerto Rico. The results showed that both stakeholder\u27s input and implementation criteria can have a significant impact when selecting among flood mitigation strategies. For the case study, when considering economic, social, and environmental criteria, the \u27Levee\u27 was the alternative that minimized the flood risks. The developed framework was shown to be easily implementable and adaptable to Decision-Maker (DM) requirements. In summary, the model can provide DMs with the information they need in order to forecast the flood risks of a community and study the effects of the mitigation alternatives to be implemented. These results could be used for budget forecast, resource allocation and for establishing flood management priorities for a watershed.\u2