scholarly journals An integrated shipment planning and storage capacity decision under uncertainty

2015 ◽  
Vol 45 (9/10) ◽  
pp. 913-937 ◽  
Author(s):  
Nyoman Pujawan ◽  
Mansur Maturidi Arief ◽  
Benny Tjahjono ◽  
Duangpun Kritchanchai
Keyword(s):  
Simulation Model ◽  
Storage Capacity ◽  
Working Hours ◽  
Service Level ◽  
Dispatching Rules ◽  
Decision Under Uncertainty ◽  
Content Type ◽  
Service Levels ◽  
And Storage ◽  
Capacity Decision

Purpose – In transportation and distribution systems, the shipment decisions, fleet capacity, and storage capacity are interrelated in a complex way, especially when the authors take into account uncertainty of the demand rate and shipment lead time. While shipment planning is tactical or operational in nature, increasing storage capacity often requires top management’s authority. The purpose of this paper is to present a new method to integrate both operational and strategic decision parameters, namely shipment planning and storage capacity decision under uncertainty. The ultimate goal is to provide a near optimal solution that leads to a striking balance between the total logistics costs and product availability, critical in maritime logistics of bulk shipment of commodity items. Design/methodology/approach – The authors use simulation as research method. The authors develop a simulation model to investigate the effects of various factors on costs and service levels of a distribution system. The model mimics the transportation and distribution problems of bulk cement in a major cement company in Indonesia consisting of a silo at the port of origin, two silos at two ports of destination, and a number of ships that transport the bulk cement. The authors develop a number of “what-if” scenarios by varying the storage capacity at the port of origin as well as at the ports of destinations, number of ships operated, operating hours of ports, and dispatching rules for the ships. Each scenario is evaluated in terms of costs and service level. A full factorial experiment has been conducted and analysis of variance has been used to analyze the results. Findings – The results suggest that the number of ships deployed, silo capacity, working hours of ports, and the dispatching rules of ships significantly affect both total costs and service level. Interestingly, operating fewer ships enables the company to achieve almost the same service level and gaining substantial cost savings if constraints in other part of the system are alleviated, i.e., storage capacities and working hours of ports are extended. Practical implications – Cost is a competitive factor for bulk items like cement, and thus the proposed scenarios could be implemented by the company to substantially reduce the transportation and distribution costs. Alleviating storage capacity constraint is obviously an idea that needs to be considered when optimizing shipment planning alone could not give significant improvements. Originality/value – Existing research has so far focussed on the optimization of shipment planning/scheduling, and considers shipment planning/scheduling as the objective function while treating the storage capacity as constraints. The simulation model enables “what-if” analyses to be performed and has overcome the difficulties and impracticalities of analytical methods especially when the system incorporates stochastic variables exhibited in the case example. The use of efficient frontier analysis for analyzing the simulation results is a novel idea which has been proven to be effective in screening non-dominated solutions. This has provided the authors with near optimal solutions to trade-off logistics costs and service levels (availability), with minimal experimentation times.

Exploring incomplete information in maintenance materials inventory optimization

2014 ◽  
Vol 114 (1) ◽  
pp. 144-158 ◽  
Author(s):  
Antti Puurunen ◽  
Jukka Majava ◽  
Pekka Kess
Keyword(s):  
Sensitivity Analysis ◽  
Simulation Model ◽  
Input Data ◽  
Real Life ◽  
Significant Risk ◽  
Service Level ◽  
Content Type ◽  
Imperfect Data ◽  
Inventory Optimization ◽  
Critical Materials

Purpose – Ensuring the sufficient service level is essential for critical materials in industrial maintenance. This study aims to evaluate the use of statistically imperfect data in a stochastic simulation-based inventory optimization where items' failure characteristics are derived from historical consumption data, which represents a real-life situation in the implementation of such an optimization model. Design/methodology/approach – The risks of undesired shortages were evaluated through a service-level sensitivity analysis. The service levels were simulated within the error of margin of the key input variables by using StockOptim optimization software and real data from a Finnish steel mill. A random sample of 100 inventory items was selected. Findings – Service-level sensitivity is item specific, but, for many items, statistical imprecision in the input data causes significant uncertainty in the service level. On the other hand, some items seem to be more resistant to variations in the input data than others. Research limitations/implications – The case approach, with one simulation model, limits the generalization of the results. The possibility that the simulation model is not totally realistic exists, due to the model's normality assumptions. Practical implications – Margin of error in input data estimation causes a significant risk of not achieving the required service level. It is proposed that managers work to improve the preciseness of the data, while the sensitivity analysis against statistical uncertainty, and a correction mechanism if necessary, should be integrated into optimization models. Originality/value – The output limitations in the optimization, i.e. service level, are typically stated precisely, but the capabilities of the input data have not been addressed adequately. This study provides valuable insights into ensuring the availability of critical materials.

The strategic design of port services based on a total landed cost approach

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Rosa G. González-Ramírez ◽  
J. Rene Villalobos ◽  
Cesar Meneses
Keyword(s):  
Service Time ◽  
Public Information ◽  
Service Level ◽  
Competitive Position ◽  
Content Type ◽  
Service Levels ◽  
Strategic Design ◽  
Confidentiality Agreement ◽  
Traffic Volumes ◽  
High Level

PurposeThis paper explores the effect of port's service time, particularly the mean and variability, on shippers' total landed costs to determine the competitive position of the port and derive recommendations for the strategic design of port services.Design/methodology/approachThe competitive position of a port is estimated considering the service level offered to the end-users of the port such as port service time, its variability and its effect on the total landed costs observed by the port users. The proposed methodology is meant to help ports to determine the required service time levels to maintain or gain a competitive advantage against other ports, in terms of attracting common hinterland's customers.FindingsResults show the advantages of considering service levels factors to determine the competitive position of a port, and what are the minimum characteristics required to capture more traffic volumes, that can help port managers to take strategic design decisions to better position the port in the current fierce market.Research limitations/implicationsThe proposed methodology is illustrated by considering a case study, which is the Port of Guaymas in Mexico. Data was not directly collected by the port, but based on interviews with shippers and public information, a representative case is presented. Due to a confidentiality agreement with the Port, specific references for most of the data used to estimate the model's parameters are not provided. The analysis is intended to show the potential value of this mechanism and can be used for evaluating the competitive position, from a high-level perspective, of any port to determine potential hinterland by improving the service level of the port.Originality/valueThe existing literature on port choice and port competition has not previously considered the effect of port service levels under the perspective of total landed costs of the users, being this paper a contribution to fulfill this gap.

Simulation modeling for manpower planning in electrical maintenance service facility

2018 ◽  
Vol 24 (1) ◽  
pp. 89-104 ◽  
Author(s):  
Sanjay Choudhari ◽  
Hasmukh Gajjar
Keyword(s):  
Simulation Model ◽  
Resource Utilization ◽  
Manpower Planning ◽  
Service Level ◽  
Simulation Software ◽  
Optimum Number ◽  
Entire System ◽  
Service Facility ◽  
Content Type ◽  
Maintenance Service

Purpose The purpose of this paper is to present the simulation model for manpower planning in electrical maintenance service facility and evaluates different scenarios to improve resource utilization while meeting the desired service level. Design/methodology/approach The process systematically maps entire system of electrical fault rectification, identifies probability distributions of demand of electrical maintenance requests and its process times using historical data. The simulation software Arena was used to model the entire system and various possible improvements were evaluated to assess performance of maintenance service facility. Findings The simulation results obtained for the proposed changes in the system indicated the potential improvement in resource utilization while meeting the average waiting time expectations of customers. Practical implications The proposed simulation model can help maintenance people to decide the optimum number of resources to meet the agreed performance level that is expected by various stakeholders. Originality/value The paper considers the computer simulation in modeling complex real-life system for understanding the resource requirement of electrical fault maintenance facility to improve resource utilization while meeting the desired service level.

Customers’ needs and expectations on servicescape surveillance management

2016 ◽  
Vol 28 (6) ◽  
pp. 887-906 ◽  
Author(s):  
Angelo Bonfanti
Keyword(s):  
Focus Group ◽  
Customer Service ◽  
Service Level ◽  
Economic Security ◽  
Retail Stores ◽  
Service Experience ◽  
Content Type ◽  
Service Levels ◽  
To Receive ◽  
Service Managers

Purpose The purpose of this paper is to identify customers’ needs and expectations regarding servicescape surveillance management (SSM) in order to suggest to service managers how they can carefully design a service environment to ensure a high level of security while concurrently enhancing the customer service experience. Design/methodology/approach Given that this study is explorative in nature, it is based on a specific method of qualitative data collection: focus group interviews. Three focus group sessions were organised with 24 Italian customers of retail stores, hotels and hospitals. The multi-expectation model proposed by Parasuraman, Berry and Zeithaml, which distinguishes between what customers consider acceptable (adequate service level) and what they hope to receive (desired service level), was chosen as the reference framework to investigate customers’ needs and expectations from SSM. Findings Servicescape surveillance must be compatible with customer satisfaction. Customers are acceptably satisfied when servicescape surveillance offers them feelings of physical safety, psychological security, economic security and the right to privacy. They desire that surveillance also allows them to live a positive service experience in sensorial, psychological, social and temporal terms. However, customers’ expectations of adequate and desired service levels are different in terms of the presence, quantity and visibility of surveillance in the three service areas examined. Interestingly, customers expect to find more visible surveillance measures inside retail stores rather than in hotels and hospitals, but they prefer to receive invisible surveillance in the servicescape. Practical implications Service managers should consider surveillance not as a cost or a tool for detecting and punishing inappropriate or criminal behaviour, but rather, as an opportunity for enhancing the customer service experience. They can invest in servicescape design elements, technological surveillance solutions and continuous training of security personnel to meet their customers’ adequate and desired service levels. Originality/value This study provides two major contributions. From the theoretical viewpoint, it extends knowledge of the hitherto under-researched area of SSM by identifying customers’ needs and expectations of surveillance and the customer service experience, which are topics usually examined separately in the literature. In terms of managerial implications, it provides store/hotel/hospital managers with recommendations on how to design a servicescape that is both secure and pleasant.

Retail supply chain service levels: the role of inventory storage

2016 ◽  
Vol 29 (6) ◽  
pp. 887-902 ◽  
Author(s):  
Asif Salam ◽  
Farhad Panahifar ◽  
P.J. Byrne
Keyword(s):  
Supply Chain ◽  
Customer Service ◽  
Service Level ◽  
Retail Industry ◽  
Inventory Level ◽  
Content Type ◽  
Service Levels ◽  
Product Availability ◽  
Customer Service Level ◽  
The Relationship

Purpose In today’s competitive retail industry the most critical success factor is customer service which is indicated by product availability. It is argued that in the retail industry, product availability is an important measure of quality. The single most vital decision that every retailer needs to make is, how to maximize service level while keeping minimum inventory level. The purpose of this paper is to explain and demonstrate the relationship between inventory level and customer service level. Design/methodology/approach This study examines an inventory system utilizing a simulation model based on company data obtained from a retail fast-moving-consumer goods chain operating in Thailand. Findings The results suggest that the achievement of a responsive service level is dependent on managing an efficient supply chain in addition to logistics cost reductions. The findings also reveal the effect the inventory level has on the service level. From the findings of this study, demand variability and service level have been found to have the most significant influence on the inventory level. From the findings, it can also be shown that real and accurate information is very important for service supply chains. Practical implications The paper promotes the importance of having an appropriate inventory management policy for a retail chain which should be driven by retail companies in order to better balance inventory and service levels. Originality/value The relationship between the inventory level and customer service level lead to different outcomes at different combinations of inventory and service levels. Significant relationships were found between inventory and service levels.

Weighted grey relational analysis to evaluate multilevel dispatching rules in wafer fabrication

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Goh Chia Yee ◽  
Chin Jeng Feng ◽  
Mohd Azizi Bin Chik ◽  
Mohzani Mokhtar
Keyword(s):  
Simulation Model ◽  
Grey Relational Analysis ◽  
Wafer Fabrication ◽  
Dispatching Rules ◽  
Critical Ratio ◽  
Dispatching Rule ◽  
Semiconductor Wafer ◽  
Content Type ◽  
Relational Analysis ◽  
Grey Relational

PurposeThis research proposes weighted grey relational analysis (WGRA) method to evaluate the performance of 325 multilevel dispatching rules in the wafer fabrication process.Design/methodology/approachThe research methodology involves multilevel dispatching rule generation, simulations, WGRA and result analysis. A complete permutation of multilevel dispatching rules, including the partial orders, is generated from five basic rules. Performance measures include cycle time, move, tool idling and queue time. The simulation model and data are obtained from a wafer fab in Malaysia. Two seasons varying in customer orders and objective weights are defined. Finally, to benchmark performance and investigate the effect of varying values of coefficient, the models are compared against TOPSIS and VIKOR.FindingsResults show that the seasons prefer different multilevel dispatching rules. In Normal season, the ideal first basic dispatching rule is critical ratio (CR) and CR followed by shortest processing time (SPT) is the best precedence pairing. In Peak season, the superiority of the rule no longer heavily relies on the first basic rule but rather depends on the combination of tiebreaker rules and on-time delivery (OTD) followed by CR is considered the best precedence pairing. Compared to VIKOR and TOPSIS, WGRA generates more stable rankings in this study. The performance of multicriteria decision-making (MCDM) methods is influenced by the data variability, as a higher variability produces a much consistent ranking.Research limitations/implicationsAs research implications, the application illustrates the effectiveness and practicality of the WGRA model in analyzing multilevel dispatching rules, considering the complexity of the semiconductor wafer fabrication system. The methodology is useful for researchers wishing to integrate MCDM model into multilevel dispatching rules. The limitation of the research is that the results were obtained from a simulation model. Also, the rules, criteria and weights assigned in WGRA were decided by the management. Lastly, the distinguishing coefficient is fixed at 0.5 and the effect to the ranking requires further study.Originality/valueThe research is the first deployment WGRA in ranking multilevel dispatching rules. Multilevel dispatching rules are rarely studied in scheduling research although studies show that the tiebreakers affect the performances of the dispatching rules. The scheduling reflects the characteristics of wafer fabrication and general job shop, such as threshold and look-ahead policies.

Clinical governance in Australia

2015 ◽  
Vol 20 (2) ◽  
pp. 56-73 ◽  
Author(s):  
Allan D Spigelman ◽  
Shane Rendalls
Keyword(s):  
Web Sites ◽  
Service Providers ◽  
Service Level ◽  
Clinical Governance ◽  
Success Factor ◽  
Quality And Safety ◽  
Funding Policy ◽  
Content Type ◽  
Health Service Providers ◽  
Governance Systems

Purpose – The purpose of this paper is to overview, background and context to clinical governance in Australia, areas for further development and potential learnings for other jurisdictions. Design/methodology/approach – Commentary; non-systematic review of clinical governance literature; review of web sites for national, state and territory health departments, quality and safety organisations, and clinical colleges in Australia. Findings – Clinical governance in Australia shows variation across jurisdictions, reflective of a fragmented health system with responsibility for funding, policy and service provision being divided between levels of government and across service streams. The mechanisms in place to protect and engage with consumers thus varies according to where one lives. Information on quality and safety outcomes also varies; is difficult to find and often does not drill down to a service level useful for informing consumer treatment decisions. Organisational stability was identified as a key success factor in realising and maintaining the cultural shift to deliver ongoing quality. Research limitations/implications – Comparison of quality indicators with clinical governance systems and processes at a hospital level will provide a more detailed understanding of components most influencing quality outcomes. Practical implications – The information reported will assist health service providers to improve information and processes to engage with consumers and build further transparency and accountability. Originality/value – In this paper the authors have included an in depth profile of the background and context for the current state of clinical governance in Australia. The authors expect the detail provided will be of use to the international reader unfamiliar with the nuances of the Australian Healthcare System. Other studies (e.g. Russell and Dawda, 2013; Phillips et al., n.d.) have been based on deep professional understanding of clinical governance in appraising and reporting on initaitives and structures. This review has utilised resources available to an informed consumer seeking to understand the quality and safety of health services.

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