Customer Service Requirements Research Articles

A SYNCHRONIZED MODELLING APPROACH FOR STRATEGIC AND OPERATIONAL PLANNING OF THE SUPPLY CHAIN

ABSTRACT Many previous supply chain (SC) management researches focused only on the individual segment of the SC. This paper proposes a synthetic approach, which combines the strategic and operational planning tasks of the SC management. In this synchronized planning approach, the centralized coordination framework can consider the production and marketing preferences as well as customer service requirements, and make optimal strategic suggestions of the SC configuration and material flows with the minimal total SC cost. Moreover, the corresponding operational planning decisions for raw material management, production control, finished products stockpile control, and distribution control are also generated. Sensitivity analyses are performed to demonstrate the applicability and effectiveness of the synchronized model under a wide range of SC planning scenarios. Simulation results show that the proposed planning approach can assist the SC planner in designing the optimal SC system.

Rescheduling for Multiple New Orders

Aset of original jobs has been scheduled on a single machine, but not processed, when a set of new jobs arrives. The decision maker needs to insert the new jobs into the existing schedule without excessively changing it. The objective is minimization of the maximum lateness of the jobs, subject to a customer service requirement modeled by a limit on the maximum time change of the original jobs. Because the schedule of the original jobs can be arbitrary, this problem models multiple disruptions from repeated new job arrivals. We show that this scheduling problem is intractable, even if no new jobs arrive. We describe several approximation algorithms and analyze their worst-case performance. Next, we develop a branch and bound algorithm that uses a variable neighborhood descent algorithm to obtain an initial upper bound, several dominance properties that we establish, and a lower bounding scheme based on a preemptive relaxation of the problem. The branch and bound algorithm solves 99.9% of randomly generated instances with up to 1,000 jobs within 60 CPU seconds. Our work demonstrates for the first time that optimization of large scale, intractable rescheduling problems is possible. More generally, it refocuses the literature on scheduling problems towards rescheduling issues.

Optimising the service mix for Irish hoteliers: the challenge for small food suppliers

PurposeThis paper seeks to investigate Irish hoteliers' customer service requirements of their food suppliers and to measure the trade‐offs that hotel buyers are willing to make during the purchase decision.Design/methodology/approachThe study is based on a quota sample of 100 hotels throughout the Republic of Ireland. Drawing on earlier research and applying conjoint analysis, the study demonstrates how customer service improvements may be achieved through variations in the customer service mix.FindingsFindings indicate that, for short shelf‐life products, frequency of deliveries and the ability to carry out emergency deliveries generate the highest levels of utility. More utility is created by lower prices in the case of long shelf‐life products. Small food suppliers are found to perform better on product quality and are more responsive in terms of product delivery than larger suppliers. They are perceived to be weaker on pricing, product assortment, and innovation.Research limitations/implicationsThe small number of observations for both four‐ and five‐star hotels in the sample limited the effectiveness of cluster analysis, which would greatly assist suppliers targeting specific markets with customer service bundles.Practical implicationsBy highlighting the trade‐offs that buyers use in evaluating customer service, the findings provide suppliers with the basis for assessing their own particular service mix. An improvement in perceived customer service may be achieved by reallocating the given resources and effort in favour of those parts of the mix that generate most value for the buyer. The identified trade‐offs also provide manufacturers with the criteria that can be usefully applied to evaluate competing distributors for their products.Originality/valueBy focusing on the hotel sector, the paper provides insights into a much ignored market for food suppliers, which differs considerably from mainstream grocery in terms of concentration, buyer processes and buying criteria.

Estimating aggregate resource reservation for dynamic, scalable, and fair distribution of bandwidth

The current best effort approach to Quality of Service in the Internet can no longer satisfy a diverse variety of customer service requirements, and that is why there is a need for alternative strategies. In order to solve this problem a number of service differentiation approaches have been proposed. Unfortunately, these schemes are often inadequate for providing proper service differentiation during periods of congestion. In this paper we introduce a new Bandwidth Distribution mechanism for supporting per-flow Quality of Service guarantees and for dealing with congestion. The Bandwidth Distribution scheme dynamically adjusts resource allocations at the network boundaries based on the network feedback. Within the Bandwidth Distribution framework we introduce a set of techniques for computing per-flow fair share. We evaluate these methods through simulation.

A resource-allocation queueing fairness measure

Fairness is a major issue in the operation of queues, perhaps it is the reason why queues were formed in the first place. Recent studies show that the fairness of a queueing system is important to customers not less than the actual delay they experience. Despite this observation little research has been conducted to study fairness in queues, and no commonly agreed upon measure of queue fairness exists. Two recent research exceptions are Avi-Itzhak and Levy [1], where a fairness measure is proposed, and Wierman and Harchol-Balter [18] (this conference, 2003), where a criterion is proposed for classifying service policies as fair or unfair; the criterion focuses on customer service requirement and deals with fairness with respect to service times.In this work we recognize that the inherent behavior of a queueing system is governed by two major factors: Job seniority (arrival times) and job service requirement (service time). Thus, it is desired that a queueing fairness measure would account for both. To this end we propose a Resource Allocation Queueing Fairness Measure, (RAQFM), that accounts for both relative job seniority and relative service time. The measure allows accounting for individual job discrimination as well as system unfairness. The system measure forms a full scale that can be used to evaluate the level of unfairness under various queueing disciplines. We present several basic properties of the measure. We derive the individual measure as well as the system measure for an M/M/1 queue under five fundamental service policies: Processor Sharing (PS), First Come First Served (FCFS), Non-Preemptive Last Come First Served (NP-LCFS), Preemptive Last Come First Served (P-LCFS), and Random Order of Service (ROS). The results of RAQFM are then compared to those of Wierman and Harchol-Balter [18], and the quite intriguing observed differences are discussed.

E‐fulfillment: the strategy and operational requirements

An e‐fulfillment system is designed to meet the high order volume and stringent customer service requirements of global business‐to‐consumer e‐commerce. The system converts the traditional warehouse into a multi‐channel e‐fulfillment center. In the e‐commerce environment, some of the toughest decisions must be made on little or no hard information. In this study, the nature of e‐business and the typical fulfillment process are discussed. The authors further examine the strategy and operational requirements for e‐fulfillment. This article is concluded with the implication of a successful e‐fulfillment system, a suggested design of an e‐fulfillment center, and the future research focuses.

Modeling and design of global logistics systems: A review of integrated strategic and tactical models and design algorithms

The overall focus of this research is to demonstrate the savings potential generated by the integration of the design of strategic global supply chain networks with the determination of tactical production–distribution allocations and transfer prices. The logistics systems design problem is defined as follows: given a set of potential suppliers, potential manufacturing facilities, and distribution centers with multiple possible configurations, and customers with deterministic demands, determine the configuration of the production–distribution system and the transfer prices between various subsidiaries of the corporation such that seasonal customer demands and service requirements are met and the after tax profit of the corporation is maximized. The after tax profit is the difference between the sales revenue minus the total system cost and taxes. The total cost is defined as the sum of supply, production, transportation, inventory, and facility costs. Two models and their associated solution algorithms will be introduced. The savings opportunities created by designing the system with a methodology that integrates strategic and tactical decisions rather than in a hierarchical fashion are demonstrated with two case studies. The first model focuses on the setting of transfer prices in a global supply chain with the objective of maximizing the after tax profit of an international corporation. The constraints mandated by the national taxing authorities create a bilinear programming formulation. We will describe a very efficient heuristic iterative solution algorithm, which alternates between the optimization of the transfer prices and the material flows. Performance and bounds for the heuristic algorithms will be discussed. The second model focuses on the production and distribution allocation in a single country system, when the customers have seasonal demands. This model also needs to be solved as a subproblem in the heuristic solution of the global transfer price model. The research develops an integrated design methodology based on primal decomposition methods for the mixed integer programming formulation. The primal decomposition allows a natural split of the production and transportation decisions and the research identifies the necessary information flows between the subsystems. The primal decomposition method also allows a very efficient solution algorithm for this general class of large mixed integer programming models. Data requirements and solution times will be discussed for a real life case study in the packaging industry.

Electronic Commerce and Logistics Planning: An Underrated Relationship

The study aims to describe the relationship existing between electronic commerce and business logistics, highlighting the impact that such a branch of the new economy will have on the logistics structures, in the next future. The purpose of this paper is also to identify the organizational model characterizing the outbound logistics process and that will most likely be implemented by those companies that will be succesful in the electronic commerce (B2C) of physical products. In order to provide further design advices, a specific section of this paper has been dedicated to the identification of the critical variables that may influence the design of the logistics network, with specific reference to the logistics last mile issue. The analysis of the combination of such variables has allowed the formulation of a reference framework which can easily be used to evaluate the main distribution alternatives: direct (home) delivery to final customer vs. delivery through a logistics platform (sales outlet, cross docking point, local distribution center, etc.).With this framework it is possible to more accurately understand the relationships among customer service requirements and cost levels, variables that can be managed by the network designer and choices of the most effective way to perform the physiacal delivery service.

Customer service based design of the supply chain

The purpose of this study is to propose a framework by which service elements and a company's own strategies can be included in the “traditional”, cost-based design of the supply chain. The framework is demonstrated with a numerical example and it is based on integrating the analytic hierarchy process (AHP) and mixed integer programming (MIP). The target is to optimise a company's supply chain based on customer service requirements within the constraints of the supply chain.

A Supply Network Model with Base-Stock Control and Service Requirements

We develop a supply network model that takes as input the bill of materials, the (nominal) lead times, the demand and cost data, and the required customer service levels. In return, the model generates the base-stock level at each store—the stocking location for a part or an end-product, so as to minimize the overall inventory capital throughout the network and to guarantee the customer service requirements. The key ingredient of the model is a detailed, albeit approximate, analysis of the actual lead times at each store and the associated demand over such lead times, along with a characterization of the operation at each store via an inventory-queue model. The gradients are derived in explicit forms, and a conjugate gradient routine is used to search for the optimal solution. Several numerical examples are presented to validate the model and to illustrate its various features.

Determining inventory levels in a CONWIP controlled job shop

We extend the concept of CONWIP control to a job shop setting, in which multiple products with distinct routings compete for the same set of resources. The problem is to determine the fixed overall WIP level and its allocation to product types (WIP mix) to meet a uniformly high customer service requirement for each product type. We formulate an optimization problem for an open queuing network model in which customer orders pull completed products from the system. Then, assuming heavy demand, we derive a throughput target for each product type in a closed queuing network and provide a simple heuristic to find a minimum total WJP and WIP mix that will achieve an operating throughput close to this target. In numerical examples, the WIP mix suggested by this approach achieves the customer service requirement with a relatively low total WIP

Sharpening logistics customer service strategy planning by applying Kano's quality element classification

This paper presents how logistics customer service requirements can be analysed by using Kano's model of quality element classification, and discusses the potential benefits that can be achieved by applying this approach to a logistics customer service planning process. According to the model of Kano's, quality elements should be classified into three classes depending on their ability to create customer satisfaction or cause dissatisfaction: elements of expected quality, attractive quality, and one-dimensional quality. This study suggests that logistics customer service elements could be classified analogously with Kano's model to identify the most important customer service elements, and to effectively distinguish the differences between customer groups. Differences between traditional approaches and Kano's classification are discussed.

The antecedents of employee commitment to customer service: evidence from a UK

This paper provides a first attempt at conceptualizing and operationalizing the notion of commitment to customer service (CCS) as part of a broader concern to explore the determinants of key aspects of service quality and of individual-level performance in service organizations. Based on an explicitly behavioral definition of commitment to customer service, we first set out a model of the antecedents of CCS. We then test it using data from a representative sample of 717 employees of a major food-retailing organization in the UK. The results suggest that commitment to customer service is primarily a non-calculative phenomenon driven above all by affective. normative altruistic concerns, rather than by overtly instrumental considerations. Additional significant determinants of CCS were job pressure, job routinization. job competence and employees' understanding of customer service requirements. Research and policy implications of the study are discussed.

Distribution of spatial requirements for a MAP/G/1 queue when space and service times are dependent

In this paper, we consider a MAP/G/1 queue in which each customer arrives with a service and a space requirement, which could be dependent. However, the space and service requirements of different customers are assumed to be independent. Each customer occupies its space requirement in a buffer until it has completely received its service, at which time, it relinquishes the space it occupied. We study and solve the problem of finding the steady-state distribution of the total space requirement of all customers present in the system. In the process of doing so, we also generalize the solution of the MAP/G/1 queue and find the time-average joint distribution of the queue-length, the state of the arrival process and the elapsed service time, conditioned on the server being busy. This problem has applications to the design of buffer requirements for a computer or communication system.

Optimal scheduling policies in time sharing service systems

We consider optimal scheduling problems in a TSSS (Time Sharing Service System), i.e., a tandem queueing network consisting of multiple service stations, all of which are served by a single server. In each station, a customer can receive service time up to the prescribed station dependent upper bound, but he must proceed to the next station in order to receive further service. After the total amount of the received services reaches his service requirement, he departs from the network. The optimal policy for this system minimizes the long-run average expected waiting cost per unit of time over the infinite planning horizon. It is first shown that, if the distribution of customer's service requirement is DMRL (Decreasing Mean Residual Life), the policy of giving the highest priority to the customer with the most attained service time is optimal under a set of some appropriate conditions. This implies that any policy without interruptions and preemptions of services is optimal. If the service requirement is DFR (Decreasing Failure Rate), on the other hand, it is shown that the policy of giving the highest priority to the customer with the least attained service time, i.e., the so-called LAST (Least Attained Service Time first) is optimal under another set of some appropriate conditions. These results can be generalized to the case in which there exist multiple classes of customers, but each class satisfies one of the above sets of conditions.

A state-dependent GI/G/1 queue

We consider a state-dependent GI/G/1 queueing system characterized by the unfinished work U(t) in the system at time t. We introduce state-dependence by allowing (i) the arrival process to depend on the instantaneous value of U(t), (ii) the service rate, that is, the rate at which U(t) decreases in the absence of arrivals, to depend on U(t), and (iii) the customer's service requirement to depend on U(t*) where t* denotes the instant in which that customer entered the system. We consider the limit of short inter-arrival times and small service requests and compute asymptotic approximations to the stationary density of the unfinished work, including the stationary probability of finding the system empty, using the WKB method and the method of matched asymptotic expansions.

Measuring the performance of intermodal freight terminals

As the interface point between road and rail, intermodal freight terminals (IFTs) are critical elements in the total freight distribution chain. This paper addresses the twin objectives of reducing freight transport costs and improving customer service by putting forward a number of indicators designed to measure the performance of IFTs. Each of the three major performance areas, namely customer service, operational efficiency and terminal productivity are discussed in detail. A methodology is put forward which enables operating strategies to be evaluated. Computer simulation is used in order to arrive at strategies which reduce operating and capital costs and satisfy customer service requirements. The simulation model outputs include performance measures related to customer service such as mean waiting times required for loading and unloading of containers, as well as productivity measures of terminal operations such as lifting equipment utilisation.

Switched poisson process/g/1 queue with service interruptions

In this paper, we develop an expression for the expected waiting time in a single server queueing system subject to interruptions with alternately varying Poisson arrival and renewal service rates. This queueing system is useful to model situations in production, computer and telecommunication systems in which customer arrivals and service requirements differ depending on whether the server is working or not. We develop an expression for the expected waiting time by approximating the virtual delay process by a Brownian motion. Our approximation for the expected waiting time involves only the means and variances and does not depend on any assumptions regarding the interarrival, service or switching time distributions. We present simulation results to illustrate the quality of our approximations.

Service Net-2000: An Intelligent Network Evolution

Rapid technological changes in the computing and telecommunications industries are expanding customer expectations and service requirements for the public network. Meeting these needs will require several major changes in the network, notably in the areas of high-bandwidth services, faster service-provisioning times (i.e., improved operations, administration, maintenance, and provisioning), and increased network intelligence. In this paper, we describe how AT&T Network Systems plans to use Service Net-2000 to support these changes. The Service Net-2000 architecture will integrate high-capacity switching and data-networking elements with synchronous optical network (SONET) transmission elements under a unified, customer-oriented, common control structure. Because it is evolving directly from today's 5ESS® switch, Service Net-2000 will incorporate all the capabilities of today's real-world intelligent network. By using intelligent network adjuncts, service circuit nodes, and service control points within this architecture, we will be able to offer a broad range of services faster and easier than we can today. These concepts form the basis for future service offerings that will create a more responsive, service-rich public network ready to meet the information movement needs of end users.

Customer Service Requirements of German Importers

Customer Service has become an integral part of the marketing offering of many successful companies. The recognition that the provision of the correct service levels has demand generating properties has led to more interest in the correct composition of such service levels. Unfortunately because customer service is comprised of various multi-functional components, there is no one correct set of components for all situations. This article shows the importance of obtaining customer/prospective customer-based perceptions about which components are the most important factors in the development of customer service levels. Manufacturer perceptions of customer requirements, if used to develop customer service offerings, may lead to provision of superior levels of unimportant service factors, whilst at the same time neglecting very important factors. It is also important to ask customers for our standing in terms of service levels, compared to our competitors. It is no longer good enough to take no complaints as ...