Auke Pot - Academia.edu (original) (raw)

Papers by Auke Pot

Research paper thumbnail of Proceedings of the 2003 Winter Simulation Conference

We give an approximation method for analyzing the performance of call centers with skill-based ro... more We give an approximation method for analyzing the performance of call centers with skill-based routing, for both blocking and delay systems. We use this method to determine optimal skill sets for call center employees.

Research paper thumbnail of An Overview of Routing and Stang Algorithms in Multi-Skill Customer Contact Centers

This paper gives an overview of routing and stang algorithms in multi-skill contact centers. Rela... more This paper gives an overview of routing and stang algorithms in multi-skill contact centers. Related issues and problems are characterized, and models and mathematical tools from the literature for modeling and optimizing contact centers are described. In addition, a general model of a multi-skill contact center is described and the papers from the literature are put in that framework.

Research paper thumbnail of A Simple Stang Method for Multi-Skill Call Centers

We study a simple method for stang in multi-skill call centers. The method has short computation ... more We study a simple method for stang in multi-skill call centers. The method has short computation times and determines nearly optimal stang levels. It is in both views competitive to other methods from the literature. Due to the fast and accurate performance of the method, many dierent scenarios can be analyzed, and our method can be used for both tactical

Research paper thumbnail of Approximating multi-skill blocking systems by HyperExponential Decomposition

Performance Evaluation, 2006

We consider multi-class blocking systems in which jobs require a single processing step. There ar... more We consider multi-class blocking systems in which jobs require a single processing step. There are groups of servers that can each serve a different subset of all job classes. The assignment of jobs occurs according to some fixed overflow policy. We are interested in the blocking probabilities of each class. This model can be used for call centers, tele-communication and computer networks. An approximation method is presented that takes the burstiness of the overflow processes into account. This is achieved by assuming hyperexponential distributions of the inter-overflow times. The approximations are validated with simulation and we make a comparison to existing approximation methods. The overall blocking probability turns out to be approximated with high accuracy by several methods. However, the individual blocking probabilities per class are significantly more accurate for the method that is introduced in this paper.

Research paper thumbnail of A Simple Staffing Method for Multiskill Call Centers

Manufacturing & Service Operations Management, 2008

W e study a simple method for staffing in multiskill call centers. The method has short computati... more W e study a simple method for staffing in multiskill call centers. The method has short computation times and determines nearly optimal staffing levels. It is in both views competitive to other methods from the literature. Because of the fast and accurate performance of the method, many different scenarios can be analyzed, and our method can be used for both tactical and strategic capacity management decisions.

Research paper thumbnail of Simple Methods for Shift Scheduling in Multiskill Call Centers

Manufacturing & Service Operations Management, 2008

T his paper introduces a new method for shift scheduling in multiskill call centers. The method c... more T his paper introduces a new method for shift scheduling in multiskill call centers. The method consists of two steps. First, staffing levels are determined, and next, in the second step, the outcomes are used as input for the scheduling problem. The scheduling problem relies on a linear programming model that is easy to implement and has short computation times, i.e., a fraction of a second. Therefore, it is useful for different purposes and it can be part of an iterative procedure: for example, one that combines shifts into rosters.

Research paper thumbnail of Workload minimization in re-entrant lines

European Journal of Operational Research, 2006

This paper is concerned with workload minimization in re-entrant lines with exponential service t... more This paper is concerned with workload minimization in re-entrant lines with exponential service times and preemptive control policies. Using a numerical algorithm called the power series algorithm we obtain nearly optimal policies for systems with up to 8 queues. We also improve considerably the implementation of the power series algorithm.

Research paper thumbnail of ROUTING HEURISTICS FOR MULTI-SKILL CALL CENTERS

We give an approximation method for analyzing the per-formance of call centers with skill-based r... more We give an approximation method for analyzing the per-formance of call centers with skill-based routing, for both blocking and delay systems. We use this method to deter-mine optimal skill sets for call center employees. ... Planning issues in call centers are a fruitful research ...

Research paper thumbnail of Customer relations management: call center operations: routing heuristics for multi-skill call centers

Winter Simulation Conference, 2003

We give an approximation method for analyzing the performance of call centers with skill-based ro... more We give an approximation method for analyzing the performance of call centers with skill-based routing, for both blocking and delay systems. We use this method to determine optimal skill sets for call center employees.

Research paper thumbnail of Online scheduling policies for multiclass call centers with impatient customers

European Journal of Operational Research, 2010

We consider a call center with two classes of impatient customers: premium and regular classes. M... more We consider a call center with two classes of impatient customers: premium and regular classes. Modeling our call center as a multiclass GI/GI/s + M queue, we focus on developing scheduling policies that satisfy a target ratio constraint on the abandonment probabilities of premium customers to regular ones. The problem is inspired by a real call center application in which we want to reach some predefined preference between customer classes for any workload condition. The motivation for this constraint comes from the difficulty of predicting in a quite satisfying way the workload. In such a case, the traditional routing problem formulation with differentiated service levels for different customer classes would be useless. For this new problem formulation, we propose two families of online scheduling policies: queue joining and call selection policies. The principle of our policies is that we adjust their routing rules by dynamically changing their parameters. We then evaluate the performance of these policies through a numerical study. The policies are characterized by simplicity and ease of implementation.

Research paper thumbnail of Proceedings of the 2003 Winter Simulation Conference

We give an approximation method for analyzing the performance of call centers with skill-based ro... more We give an approximation method for analyzing the performance of call centers with skill-based routing, for both blocking and delay systems. We use this method to determine optimal skill sets for call center employees.

Research paper thumbnail of An Overview of Routing and Stang Algorithms in Multi-Skill Customer Contact Centers

This paper gives an overview of routing and stang algorithms in multi-skill contact centers. Rela... more This paper gives an overview of routing and stang algorithms in multi-skill contact centers. Related issues and problems are characterized, and models and mathematical tools from the literature for modeling and optimizing contact centers are described. In addition, a general model of a multi-skill contact center is described and the papers from the literature are put in that framework.

Research paper thumbnail of A Simple Stang Method for Multi-Skill Call Centers

We study a simple method for stang in multi-skill call centers. The method has short computation ... more We study a simple method for stang in multi-skill call centers. The method has short computation times and determines nearly optimal stang levels. It is in both views competitive to other methods from the literature. Due to the fast and accurate performance of the method, many dierent scenarios can be analyzed, and our method can be used for both tactical

Research paper thumbnail of Approximating multi-skill blocking systems by HyperExponential Decomposition

Performance Evaluation, 2006

We consider multi-class blocking systems in which jobs require a single processing step. There ar... more We consider multi-class blocking systems in which jobs require a single processing step. There are groups of servers that can each serve a different subset of all job classes. The assignment of jobs occurs according to some fixed overflow policy. We are interested in the blocking probabilities of each class. This model can be used for call centers, tele-communication and computer networks. An approximation method is presented that takes the burstiness of the overflow processes into account. This is achieved by assuming hyperexponential distributions of the inter-overflow times. The approximations are validated with simulation and we make a comparison to existing approximation methods. The overall blocking probability turns out to be approximated with high accuracy by several methods. However, the individual blocking probabilities per class are significantly more accurate for the method that is introduced in this paper.

Research paper thumbnail of A Simple Staffing Method for Multiskill Call Centers

Manufacturing & Service Operations Management, 2008

W e study a simple method for staffing in multiskill call centers. The method has short computati... more W e study a simple method for staffing in multiskill call centers. The method has short computation times and determines nearly optimal staffing levels. It is in both views competitive to other methods from the literature. Because of the fast and accurate performance of the method, many different scenarios can be analyzed, and our method can be used for both tactical and strategic capacity management decisions.

Research paper thumbnail of Simple Methods for Shift Scheduling in Multiskill Call Centers

Manufacturing & Service Operations Management, 2008

T his paper introduces a new method for shift scheduling in multiskill call centers. The method c... more T his paper introduces a new method for shift scheduling in multiskill call centers. The method consists of two steps. First, staffing levels are determined, and next, in the second step, the outcomes are used as input for the scheduling problem. The scheduling problem relies on a linear programming model that is easy to implement and has short computation times, i.e., a fraction of a second. Therefore, it is useful for different purposes and it can be part of an iterative procedure: for example, one that combines shifts into rosters.

Research paper thumbnail of Workload minimization in re-entrant lines

European Journal of Operational Research, 2006

This paper is concerned with workload minimization in re-entrant lines with exponential service t... more This paper is concerned with workload minimization in re-entrant lines with exponential service times and preemptive control policies. Using a numerical algorithm called the power series algorithm we obtain nearly optimal policies for systems with up to 8 queues. We also improve considerably the implementation of the power series algorithm.

Research paper thumbnail of ROUTING HEURISTICS FOR MULTI-SKILL CALL CENTERS

We give an approximation method for analyzing the per-formance of call centers with skill-based r... more We give an approximation method for analyzing the per-formance of call centers with skill-based routing, for both blocking and delay systems. We use this method to deter-mine optimal skill sets for call center employees. ... Planning issues in call centers are a fruitful research ...

Research paper thumbnail of Customer relations management: call center operations: routing heuristics for multi-skill call centers

Winter Simulation Conference, 2003

We give an approximation method for analyzing the performance of call centers with skill-based ro... more We give an approximation method for analyzing the performance of call centers with skill-based routing, for both blocking and delay systems. We use this method to determine optimal skill sets for call center employees.

Research paper thumbnail of Online scheduling policies for multiclass call centers with impatient customers

European Journal of Operational Research, 2010

We consider a call center with two classes of impatient customers: premium and regular classes. M... more We consider a call center with two classes of impatient customers: premium and regular classes. Modeling our call center as a multiclass GI/GI/s + M queue, we focus on developing scheduling policies that satisfy a target ratio constraint on the abandonment probabilities of premium customers to regular ones. The problem is inspired by a real call center application in which we want to reach some predefined preference between customer classes for any workload condition. The motivation for this constraint comes from the difficulty of predicting in a quite satisfying way the workload. In such a case, the traditional routing problem formulation with differentiated service levels for different customer classes would be useless. For this new problem formulation, we propose two families of online scheduling policies: queue joining and call selection policies. The principle of our policies is that we adjust their routing rules by dynamically changing their parameters. We then evaluate the performance of these policies through a numerical study. The policies are characterized by simplicity and ease of implementation.