Inventory Reduction Research Articles

Emission Reduction Opportunities in a Rapidly Growing Economy

Vietnam’s Green Growth Action Plan for the period 2014–2020 sets out an overall plan for the sustainable development of the country. One of the cornerstones of that plan is the development of a greenhouse gas inventory and emission reduction opportunity assessment for Ho Chi Minh City. This provides a basis for the roadmap towards green growth in Ho Chi Minh City, one of Vietnam’s largest cities. Marginal costs of 38 emission reduction measures were determined for two main economy sectors, namely energy (32 measures) and agriculture, forestry, and other land use (6 measures). From that analysis, a marginal abatement cost curve was compiled for the energy sector. The total emission reduction opportunities available in 2020 are estimated to be 8.97 million tCO2e, which represents a 14.7% reduction compared to business as usual. Even when the city only implements reduction measures with negative marginal costs (i.e., abatement that saves money), significant reductions of 5.25 MtCO2e (8.6% reduction compared to business as usual) would be achieved. There are significant similarities in abatement opportunities between Ho Chi Minh City and Hanoi, Vietnam’s capital. The case study shows significant reduction in greenhouse gas emissions can be achieved in fast-growing cities with an appropriate level of investment and government support.

Fluidization of micro-interconnected fluidized beds for chemical looping

The micro-interconnected fluidized bed (MIFB) was designed to improve the evaluation condition of oxygen carrier, which is difficult to perform in a lab-scale interconnected fluidized bed because of the large demand for bed inventory. The reduction of bed inventory in the MIFB was mainly achieved by the appropriate miniaturization of the reactor size, in which the wall effect and operating flexibility should be taken into consideration. With hematite serving as the oxygen carrier, stable and flexible fluidization could be realized with 342.9g of bed inventory. Internal perforated plates were arranged in the middle of the reactor to improve gas–solid distribution, which also could restrain the slugging formation and increase the particle residence time by 28.9%. A different fluidization phenomenon was observed in this two-stage reactor in which the particle fluidization was reconstructed in the upper chamber. Throughout 48h of cold operation, the hematite oxygen carrier attrition rate was evaluated as 0.151wt.%/h corresponding to 660h lifetime, where 12.5% of particle attrition was contributed by internal perforated plates. An excellent fitting performance was found between the pressure difference in the risers and the upward particle flow, but the correction factor should be adjusted according to the fluidization flow.

Application of Langrangian Theory in Inventory Cost Reduction of a Firm

Current events confirm the vital and dynamic need for studies that embrace Economics, Engineering, Management, and many other disciplines to confront the difficulties encountered in converting raw inputs to manufacturing outputs. This paper presents the assessment of inventory control system in a typical steel construction firm in Ibadan, Nigeria, with a view to predicting how best the inventory cost can be reduced. Data were collected by interviewing appropriate respondents at the production, stores, transport, purchasing, accounts, and wages sections of the firm and relevant documents used between the year 2014 and 2019. These were tailored towards identifying the controllable variables that were later classified using ABC Pareto analysis; implementation of an inventory model (Langrangian Multiplier) by mathematically relating the variables to the total cost; and evaluating the optimal values of the variables and the optimal cost of the system. The raw materials of the outfit were found to involve 88 items; which were grouped into 5, 20 and 63 items for classes A, B, and C respectively in accordance to ABC Pareto analysis. The identified controllable variables involved premises rent, unit ordering cost, annual demand, unit space and unit holding cost. On implementing the model, the annual total inventory cost was found to be N307,446.25, N154,667.50, and N84,035.00 for quarterly, bi-annual and annual inventory policies respectively; while the annual Economic Order Quantity (EOQ) was found to be N45,110.65 per annum. This shows that the company’s inventory cost can be reduced by N262,335.60 (85%), if the Annual Economic Order Quantity (proposed model)is implemented. This study has revealed the effect of implementing a standard inventory model for cost reduction in the area of material management.Keywords—Economics, Engineering, EOQ model, Inventory cost reduction, Management.

Potential causes and consequences of rapid mitochondrial genome evolution in thermoacidophilic Galdieria (Rhodophyta)

BackgroundThe Cyanidiophyceae is an early-diverged red algal class that thrives in extreme conditions around acidic hot springs. Although this lineage has been highlighted as a model for understanding the biology of extremophilic eukaryotes, little is known about the molecular evolution of their mitochondrial genomes (mitogenomes).ResultsTo fill this knowledge gap, we sequenced five mitogenomes from representative clades of Cyanidiophyceae and identified two major groups, here referred to as Galdieria-type (G-type) and Cyanidium-type (C-type). G-type mitogenomes exhibit the following three features: (i) reduction in genome size and gene inventory, (ii) evolution of unique protein properties including charge, hydropathy, stability, amino acid composition, and protein size, and (iii) distinctive GC-content and skewness of nucleotides. Based on GC-skew-associated characteristics, we postulate that unidirectional DNA replication may have resulted in the rapid evolution of G-type mitogenomes.ConclusionsThe high divergence of G-type mitogenomes was likely driven by natural selection in the multiple extreme environments that Galdieria species inhabit combined with their highly flexible heterotrophic metabolism. We speculate that the interplay between mitogenome divergence and adaptation may help explain the dominance of Galdieria species in diverse extreme habitats.

Cross-docks scheduling with multiple doors using fuzzy approach

One of the most important practices in logistics is Cross-Docking which sets its goals as inventory reduction and customer satisfaction increase. Customers receive goods through docks. Docks are responsible to provide a place for goods before being delivered to the customers. Then, these materials are directly loaded into outbound trucks with little or no storage in between to send to customers in the shortest possible time. This paper is mainly aimed at introducing a mixed integer, non-linear programming model to solve scheduling several cross-docking problems. The proposed model is highly facilitated to allocate the most optimal destinations to storage doors and truck scheduling in docks while selecting the collection and delivery routes. Using optimization approaches at uncertainty conditions is also of great importance. Mathematical programming techniques vividly fail to solve transportation problems that include fuzzy objective function coefficients. A fuzzy multi-objective linear programming model is proposed to solve the transportation decision-making with fuzzy objective function coefficients.

Application of a hybrid selective inventory control technique in a hospital: a precursor for inventory reduction through lean thinking

PurposeThe cost of providing healthcare is spiralling up in recent times. On the one hand, patients expect the highest quality of service, while on the other hand, the managers of the healthcare services want to minimise the total operating expenses. Hence, healthcare organisations implement lean thinking (LT) to achieve these twin objectives. LT reduces the eight wastes that are prevalent in the healthcare processes and functions. In particular, if the wasteful inventories related to expensive medical supplies are reduced, the resulting cost savings can help in providing affordable and accessible healthcare.Design/methodology/approachHence, in this paper, a case study of a hospital is presented where LT is implemented. One of the projects was related to inventory reduction in the store of the catheterisation laboratory (cath lab). A hybrid methodology called multi-unit selective inventory control (MUSIC) that combined these three dimensions (3D), namely, consumption value, criticality and lead time or ease of availability was used to classify the medical supplies into different categories.FindingsBased on the results obtained, various inventory systems and the associated tools and techniques of LT were proposed. For example, a deep dive into the A-class items revealed that some of the medical supplies fell under both vital and scarce categories. Hence, it was recommended that the case hospital should follow the economic order quantity (EOQ) with safety stock approach as these items were to be shipped from other states in India. Subsequently, the focus should be on developing a local supplier and attempts should be made to establish a kanban system with adequate information sharing.Practical implicationsThis study demonstrates the step-by-step methodology of MUSIC-3D which would guide the procurement managers to apply the same in their organisation. It also helps them in identifying appropriate elements of LT for inventory reduction before the actual deployment.Originality/valueNone of the papers has utilised the MUSIC-3D methodology as a precursor for inventory reduction, specifically within the domain of LT. Similarly, identifying and proposing different type of inventory systems and various LT practices based on this unique method is a novel attempt.

Toward more comprehensive environmental impact assessments: interlinked global models of LCIA and IAM applicable to this century

PurposeDespite the long-standing demand for research on dynamic lifecycle assessment (LCA) for policymaking, only a few studies have addressed this subject in conjunction with other systems thinking disciplines, such as energy systems models (ESMs) and integrated assessment models (IAMs), which have achieved tremendous success in assessing climate policies in future scenarios. This study explains our methodological advances in the global application of LCA incorporated in IAMs, specifically dose-response functions, models, and future scenarios.MethodsWe investigate the application of the lifecycle impact assessment method based on endpoint modeling (LIME), developed under the current environmental situation in Japan and globally, to be consistent and compatible with our IAM, which comprises three resource balance models and a simplified climate model. The IAM endogenously generates most inventories consistent with energy scenarios and climate policies linked with the applied LIME. The IAM and LIME are formulated to minimize the discounted sum of supplying the cost of resources over their lifecycles (i.e., from development to end-of-life) to generate time evolutions for the endpoint impacts over this century on a global scale with/without the 2-degree Celsius (2DC) target in a 100% renewable energy scenario.Results and discussionUnlike existing LCA+ESM/IAM studies, which focus on power generation technologies and related (in)direct embedded energy consumption on a lifecycle basis, our model’s expansion to mineral and biomass resources, in addition to energy, has the following novel results: (1) The following inventories in the 2DC target are generally lower than those in business as usual (BAU): temperature and sea level rise, natural resource, and waste discharge; further, SOx emissions are significantly reduced by reducing coal production while increasing forestry. (2) The environmental impacts on the four endpoints of minerals, land use, and land-use change, with the exclusion of energy-related impacts, are significantly larger than those related to energy. (3) Finally, by ensuring inventory reduction, the 2DC target scenario can reduce overall endpoint impacts (by maximum around 20%), except the impacts on biodiversity resulting from forestry expansion to meet predetermined targets.ConclusionsUnlike mainstream IAM analyses, we incorporate LIME, instead of energy- and biomass-related resource and climate change impacts alone; our model thus provides a comprehensive perspective on various natural resources and their impacts on a lifecycle basis. The exclusion of the weighting process and retention of the four endpoints enable us to easily interpret the results. Further, this application of LCA to IAM enables us to further understand and assess natural resources and environmental impacts.

Análise e simulação da gestão da produção de empresa: uma abordagem de dinâmica de sistemas

No âmbito da gestão da produção, devido à sua complexidade e dinamicidade, os gestores e demais tomadores de decisão devem planejar a produção e analisar o processo produtivo de forma efetiva e minuciosa. A fim de auxiliar no processo de tomada de decisão, existem diversas técnicas de modelagem e simulação de processos. Neste trabalho, o objetivo foi modelar e simular a gestão da produção em uma empresa que fabrica produtos ligados à comunicação visual com foco em produção para estoque, por meio da técnica de dinâmica de sistemas. Inicialmente, o modelo foi validado utilizando-se dados históricos e, posteriormente, simularam-se o cenário base e mais três cenários a fim de verificar o comportamento do sistema diante da redução do estoque desejado e do aumento da previsão de vendas. Concluiu-se que a análise e simulação da gestão da produção da empresa por meio da técnica de dinâmica de sistemas é viável e relevante para auxiliar os gestores na definição dos planos de vendas, estoque e produção e na identificação do impacto dos gargalos produtivos no sistema. Concluiu-se, ainda, que a atual capacidade produtiva da empresa analisada atende de forma satisfatória sua atual demanda.

Cross-docking or traditional warehousing: what is the right distribution strategy for your product?

PurposeThe objective of this paper is to investigate the impact of products' characteristics on the performance of three distribution strategies: traditional warehousing (TW), cross-docking pick by line (XDPL) and cross-docking pick by store (XDPS).Design/methodology/approachBased on a case study of an FMCG “Fast Moving Consumer Goods” company and a major French retailer, we empirically analyse the impact of the products' characteristics on the performance of the three distribution strategies. We consider a three-echelon supply chain composed of one supplier DC, one retailer DC and multiple retailer stores. The inventory at each echelon is controlled according to an order-up-to (OUT) level policy. The demand is forecasted by means of a single exponential smoothing method. A sensitivity analysis is also conducted to analyse the impact of the supply chain parameters on the comparative performance of the strategies when the parameters' values deviate from the empirical base case.FindingsThe empirical investigation shows that the use of XDPL results leads to an increase in the supply chain total cost, whereas XDPS reduces the cost. Moreover, we show that for a service-level target, cross-docking strategies should be selected for products with low variability, high shelf space, low value and short lead-time. For an inventory reduction target, these strategies should be selected for products with high demand volume. We also propose a managerial framework for choosing the right strategy for each product.Originality/valueThis paper fills a gap in the literature by presenting empirical results based on a real business case of a multi-echelon supply chain. Both cost and service are used to evaluate the performance of the strategies.Research limitations/implicationsOur work has the limitation to ignore the transportation cost implications when selecting the right distribution strategy. Hence, including such cost in the analysis would constitute an interesting extension of this work. Moreover, our empirical analysis represents a practical rich context that makes the scope for transferability of findings learned from this article substantial. However, for the generalisability of the findings, larger datasets in the retail supply chain would be interesting to consider

PNS32 PREDICTED COST-BENEFIT OF A PHARMACY INVENTORY MANAGEMENT PROGRAM FOR US ACUTE-CARE HOSPITALS

Over $27 million is spent by US hospitals on annual drug spend. Roughly 20% of hospital drug inventory is wasted or expires each year. Additionally, 50% of hospitals report manual drug inventory management methods. We created a cost-benefit model to predict the impact of a pharmacy management predictive analytics software on inventory costs. A cost-benefit model was created using Microsoft Excel to predict the economic impact of a pharmacy management predictive analytics software. Predicted benefit was calculated using a combination of drug cost data and drug utilization data. Three areas of cost-benefit were assumed: inventory reduction in patient care areas and central pharmacy, respectively, and reduction in wasted medication from more efficient management of min/max inventory levels. Inventory reduction was assumed to be a one-time cost-benefit, whereas savings due to waste reduction were repeated yearly. Cost was defined as the cost of the predictive analytics program. We analyzed cost-benefit over a five-year period using a large cohort of US acute-care hospitals. 61 acute-care hospitals were included in the cost-benefit analysis. The majority were located in the southeast (64%), had a bed size of 101-250 beds (44%), and were non-academic (39%). The model estimated annual medication spend ranging from $335,551 - $309,712,416 (median=$6,853,533). Ranges of estimated inventory reductions in patient care areas and central pharmacy were $3,000-$569,000 (median=$56,000) and $0-$1,851,000 (median=$13,500), respectively. Median projected yearly savings from waste reduction were $63,000 ($8,000-$1,443,000). Over a five-year period, cumulative cost-benefit rose from a median of $101,000 (year one) to $344,185 (year five). Estimated median ROI from adopting the intervention at year one and year five was 2.52 and 3.0, respectively. Predicted cost savings with the use of an analytics program potentially led to a five-year cumulative cost-benefit of $344,185 and a five-year ROI of 3.0. Future research should be performed to assess true/actual cost-benefit.

A Conceptual Framework for Adaptive Storage Location Assignment Considering Order Characteristics

Nowadays, the fragmented orders, the shrinking time windows, the special customer requirements, and the inventory reduction requirements are the biggest challenges in warehouse logistics and production supply. Research studies have already examined different type of order picking routing optimization and considered optimal storage location assignment (SLA). The several SLA solutions take into consideration several factors, however, these usually require the repositioning of the stored products. Based on our industrial experiments there is a lack of industrial application and support of the systems to keep up the ideal SLA. The aim of this paper is to define a potential concept to keep up a nearly optimal SLA during order picking position replenishment with minimized number of time consuming and labor-intensive product repositioning tasks.

LEAN ALATI U PREDUZEĆU ZA PROIZVODNJU PALETA

U ovom radu su prikazani osnovni proizvodni procesi u fabrici za proizvodnju paleta. U prvom delu se nalaze informacije o samoj fabrici, zatečenom stanju, problemima i gubitcima u proizvodnji. U drugom delu rada, fokus je na predlozima za unapređenje proizvodnje, koristeći 5S, Kaizen, vizuelni menadžment i Poka Yoke metode. Treći deo rada predstavlja performanse, odnosno ostvarene rezultate sprovedenih i predloženih unapređenja. Poslednji deo rada se odnosi na smanjenje troškova eksternog transporta uvođenjem DDF (diesel dual fuel) sistema, gde kao rezultat dobijamo smanjenu potrošnju goriva. Tokom celog rada, vršene su konstatne analize i unapređenja, koje su dovele do smanjenja inventara, transporta, troškova, gubitaka i defektnih proizvoda.

Have natural disasters created opportunities to initiate Big Cat Tourism in South America?

AbstractLivestock is the predominant biomass in terrestrial systems around the world, and conflict with livestock inventories continues to threaten large carnivore persistence in increasingly fragmented habitats. Nevertheless, social tolerance for large carnivores is increasing, as is interest in predator tourism, which can facilitate wildlife–livestock coexistence strategies. We report two case studies in which natural disasters led to a reduction in local livestock inventories, and subsequent economic hardships that in turn created opportunities for initiating predator tourism: jaguar tourism in the Pantanal of Brazil and puma tourism in the Patagonia steppe grasslands of southern Chile. Any time livestock numbers are reduced, whether through management decisions or natural disasters, may be considered opportunities to reduce dependency upon livestock and to weigh diversifying revenue streams via alternative activities, such as tourism. Livestock reductions in combination with a surge in the global demand for wildlife tourism have made jaguar and puma tourism an increasingly important economic activity for both regions. Well‐managed predator tourism can be effective carnivore conservation, and if integrated among other strategies, can augment conservation agendas.Abstract in Spanish is available with online material.

Predicting Reduced Tinnitus Burden After Cochlear Implantation in Adults.

Explore patient characteristics associated with tinnitus improvement after cochlear implantation. Retrospective cohort. Tertiary referral. Adults with bilateral severe-to-profound hearing loss and tinnitus. Unilateral cochlear implantation. From 1996 to 2018, 358 patients endorsed pre-implant tinnitus and had ascertainable tinnitus status at 1-year. Clinically significant improvement in Tinnitus Handicap Inventory (THI) (reduction by at least 7-points) was observed in 262 (73.2%) patients, of whom 155 (59.2%) reported complete resolution. Of the 24 characteristics explored, four were identified as independent predictors of improved tinnitus in logistic regression models. In a multivariable model including identified independent predictors, each 10-percentage point increase in baseline hearing in noise test was associated with an 14% reduction in odds of tinnitus resolution or clinically significant improvement (odds ratio [OR] 0.86, 95% confidence limits [CL] 0.77, 0.96) and preoperative use of a hearing aid in the contralateral ear was associated with a 72% reduction (OR 0.28; 95% CL 0.11, 0.73). Each 10-point increase in baseline Hearing Handicap Inventory for Adults (HHI) score was associated with a 28% increase in odds of tinnitus improvement (OR 1.28; 95% CL 1.07, 1.54). Higher baseline burden of tinnitus was associated with higher odds of tinnitus improvement (OR 1.21 per 10-point THI increase, 95% CL 1.04, 1.40). Worse residual hearing and higher baseline hearing and tinnitus handicap are associated with higher odds of tinnitus improvement. Expectations of patients seeking reduced tinnitus burden following cochlear implantation should be managed by counselling regarding odds of tinnitus improvement compared to those with similar residual hearing and tinnitus burden.

Reduction of Flammable Inventory: Use of Kanban in Research Settings

Unnecessary inventory is both wasteful and a safety risk. The Cambridge Centre for Advanced Research and Education in Singapore reviewed its flammable materials inventory, eliminated the unused excess inventory, and, to maintain the reduction and prevent a reaccumulation of unnecessary inventory, put into place a Kanban system. The efficacy of this method is documented as well as lessons learned from both the problems caused by excess unused inventory and the reasons that lead to the accumulation in the first place.

Order Classification in Inventory Planning of Job Shop Production

Customized production and provision of tailor-made services are common business models in globalized production. These can be found for example in materials research by means of high-throughput systems and the overhaul of spare parts. In both cases, there are warehouses and buffers with different requirements and limited capacity in the systems. The reactivity of these systems is therefore essential for a fast reaction to customer orders. An inventory reduction can improve this reactivity of the system but lowers the service level of short-term requests. This paper describes a method for reducing inventory levels through specific order classification. The presented method introduces how to differentiate service while considering customer-owned stocks. A validation of the model is achieved by comparing it to an analytic model and a simulation model. Results of the simulation study evaluates the applied order classification and customer stock.

Optimal control of a stochastic production inventory system with controllable backorder rate and investment to reduce inventory level variability

This paper develops an inventory model that allows the backorder rate and inventory level variability to be control variables to widen the scope of applications of Lin's (2017a) model. We assume that the backorder rate is dependent on the amount of shortages according to a negative exponential function and the supplier could offer a backorder price discount on the stock-out item by negotiation to determine a target value of backorder rate and secure more backorders. Moreover, we investigate the impact of investing in inventory level variability reduction on inventory related costs. The objective of this paper is to simultaneously determine the optimal backorder price discount, inventory level variability, and switch-over control parameters m and M to minimise the long-run total expected cost of the system and improve the competitive edge. Numerical examples are also given to demonstrate the benefits of the model.

Post-Merger Changes in Flight Frequency for Network and Low-Cost Carriers

The inventory reallocation between strategic groups is analysed after occurrence of horizontal mergers with little or no overlapping market, to reveal how players in a strategic group create, capture and raise their own, and lower others' value through cooperatively and non-cooperatively interdependent deterrence tactics. The scope is three US airline mergers occurring in 2011, 2013 and 2016. The real-time longitudinal population data was collected to analyse the causal impact of mergers on inventory (i.e., flight frequency as defined in this paper). Then, the industry's flight frequency fluctuations between strategic groups were studied. Our findings show that after mergers, there is little change on the aggregate industry inventory levels. However, a significant inventory reduction in markets where only one strategic group serves, and an obvious build-up in markets where two strategic groups compete with one group focusing on mobility barriers and the other on mutual forbearance.

Post-merger changes in flight frequency for network and low-cost carriers

The inventory reallocation between strategic groups is analysed after occurrence of horizontal mergers with little or no overlapping market, to reveal how players in a strategic group create, capture and raise their own, and lower others' value through cooperatively and non-cooperatively interdependent deterrence tactics. The scope is three US airline mergers occurring in 2011, 2013 and 2016. The real-time longitudinal population data was collected to analyse the causal impact of mergers on inventory (i.e., flight frequency as defined in this paper). Then, the industry's flight frequency fluctuations between strategic groups were studied. Our findings show that after mergers, there is little change on the aggregate industry inventory levels. However, a significant inventory reduction in markets where only one strategic group serves, and an obvious build-up in markets where two strategic groups compete with one group focusing on mobility barriers and the other on mutual forbearance.

Dual Approach to the Harmonized Model between Inventory Reduction and Heijunka (Production Leveling) based on the Minimum Average-energy Principle

A major issue in manufacturing is the balance between inventory reduction and heijunka (i.e., production leveling). To address this issue in aggregate production planning, linear programming models that consider many factors and use “exponential smoothing” as an approximate leveling method have been mainly studied. However, this methodology has problems that may limit its use as an optimal solution approximate method, and impair the timeliness required for aggregate production planning by the complexity of these models. To solve this issue, we have been developing harmonized models to balance between lowering the inventory management energy and increasing the heijunka entropy, based on demand and inventory quantities as simple optimization models. In this study, we develop a dual approach to the previously proposed model to maximize the heijunka entropy and propose a new model to minimize the inventory management energy based on the “minimum average-energy principle.” We show that the proposed model’s inventory state is lower than that of traditional exponential smoothing through numerical experiments. This study, therefore, theoretically enables a new optimal solution to the harmonized (balancing) problem, based on the concept of entropy and energy, and practically enables aggregate production planning in a timely and simple manner.