Sönke Duckwitz

A complexity measure for new product development projects

A novel complexity measure for new product development projects is introduced and its validity is evaluated. Therefore, a stochastic model of project dynamics based on previous work of Smith and Eppinger is developed. The model is able to represent the concurrent task processing of a large number of involved individuals who make at least partially autonomous decisions but also strongly interact. Because the model is stochastic in nature it can account for random and unpredictable performance fluctuations. This dynamic model is the mathematical foundation to compute the novel complexity measure-named the Effective Measure Complexity (EMC)-in a simple explicit form. The complexity theory behind the novel measure goes back to seminal work of the theoretical physicist Grassberger. His forecast complexity is an information-theoretic concept that was derived from first principles and is highly satisfactory in many respects. In the validation study a NPD project on sensor design in a small-sized company is considered and the external validity of the stochastic project model as well as the structural validity of the novel measure are analyzed. Due to the labor time system of the company, very accurate and fine-grained data about the task processing were acquired. If stopping criteria are used the results of the external validation of the dynamic model show a sufficient goodness-of-fit between the real and simulated project. The structural validation of EMC demonstrates that small complexity values are assigned to projects with uncoupled tasks, as it is intuitively required. The stronger the task couplings are, the more the complexity values grow until the stability bound of the project is reached. Beyond the stability bound the work remaining grows over all limits and the project diverges. This divergent behavior is indicated by infinite complexity values.

Development and Evaluation of a Novel Service Productivity Model

Although the early stages of engineering service development are essential, methods and tools to proactively and comprehensively evaluate the productivity of service processes are rare. Therefore, this paper presents a comprehensive model for product-service systems productivity assessment along the service provision chain. The novel productivity model distinguishes between potential, process and outcome thus covers all dimensions of a product-service system. The model further differentiates between service provider and customer from both a qualitative and quantitative point of view. A set of value drivers and success criteria is proposed in a structured manner, resulting in various levers to optimize a product-service system. The model is made fully operational by defining influence factors, representing parameters to optimize service productivity and by key figures measuring service effectiveness and efficiency. To evaluate the novel service productivity model, field data and expert opinions from two German engineering companies are considered.

Complexity assessment of human–computer interaction

A quantitative complexity theory of human–computer interaction is presented and validated by means of laboratory experiments. Based on the seminal work of Grassberger in theoretical physics, a complexity measure is introduced. The measure is termed the Effective Measure Complexity and has three main advantages. First, it relies solely on information-theoretic quantities, which are intimately connected with the concept of complexity and not randomness. Second, it is model independent and can be estimated efficiently from data. Third, the estimates can be derived from behavioural patterns in terms of observable interaction events alone. Subjective ratings or psychophysiological measurements can be included but are not mandatory. In order to explain the theory, a simple and easy to generalise example in mobile human–computer interaction is presented. Furthermore, the external validity of the complexity measure is studied in laboratory experiments. The experimental task was to search for multiple targets on an electronic chart display and information system (ECDIS). ECDIS is an integral component of modern ship bridge concepts and therefore the experiments were carried out in a marine simulator. Thirty users participated. The platform motion (with or without motion) and the workplace illumination (800 lux or 30 lux) were varied systematically and the complexity effects were studied. The results show that the complexity of the visual search processes is significantly lower when the simulator is put in sea state characteristics and the users are facing straining motion forces. In addition, interaction complexity is significantly lowered when illuminance is reduced from the daylight level of 800 lux to the twilight level of 30 lux. Therefore, the complexity measure seems to be a valid for the quantitative assessment of human–computer interaction.

Activity- and actor-oriented simulation approach for the management of development projects

The complexity of a single project – resulting from the amount of activities to be accounted for as well as the required resources – and the amount of simultaneously running projects within an enterprise are rapidly increasing. In order to stay competitive, those factors relevant for the success of project planning and execution, e.g., the project duration or budget, must be specifically identified and realised. On this basis, we developed an integrative simulation model that connects the advantages of existing activity- and actor-oriented models. The integrative model presented here is a key component of the project engineering approach and enables the automatic creation and prospective benchmarking of complex, detailed project plans. The specific aspects of the new, innovative simulation model were developed in cooperation with enterprises of the chemical industry and were verified in different development projects.

Age-Differentiated Modeling and Prediction of the Learning Time of Sensorimotor Tasks

A model to predict learning time for young people was developed by Jeske. In this paper, we extended Jeske’s model by analyzing and modeling the learning time of older people. Therefore, a replication of Jeske’s study on the influence of task descriptions on the learning time was conducted. Sixty participants took part in this study. Their experimental task was a tenfold repeated assembly of a carburetor. In each trial the execution time and the number of errors were measured and analyzed with respect to the age of the participants and the task description. Furthermore, it was investigated how well Jeske’s model can be fitted to the acquired data. The results show a significant influence of the age on the learning time. Furthermore, a significant deviation between the data and Jeske’s model is revealed. Thus, a power function model fits the data of older participants in the most appropriate way.

Modeling and Simulation of Service Systems with Design Structure and Domain Mapping Matrices

In developing and developed countries industrial, knowledge intensive services play an important role. Companies face problems in efficient and effective development and operation of new services because, among others, of their traditional, production-oriented systems and the characteristics of knowledge intensive services. A novel approach combining design structure matrices and discrete event simulation can help to improve knowledge intensive service systems development and delivery and to foster company’s competitiveness. The paper presents the underlying models focusing on service specific characteristics along the potential, process and outcome dimension of the service systems composition. Structural characteristics are supplemented by considering specific dynamic behavior in complex systems like overlapping and iterations. In a case study in the chemical engineering industry the utility of the approach is evaluated. The results can be used to support development decision as well as for identifying levers for improvement.

Analysis of human reliability in computer-aided design

Human reliability is an essential quality of Computer Aided Design (CAD) in new product development (NPD). Based on the proposals of the German VDI 2221 guideline for CAD product development, a semiotic human-machine model is adapted to examine human reliability in new product development, especially regarding time constraints. For this goal, a CAD experiment (n=116) with three VDI-2221 compliant modeling, design and assembly tasks was carried out and empirically analyzed.

A meta-model for actor-oriented, person-centered simulation for the management of development projects

The simulation of work organizations in product development projects currently occurs almost entirely in a task and process-based manner, whereas the workers involved are only considered in an undifferentiated manner. The intended use of these approaches is the optimization of project progressions to minimize the project duration and cost. Although simulation models for project organizations exist, an optimal course of a project is often not achieved in reality. Therefore, a simulation model is presented to identify realistic courses of product development projects by taking the workers in the center of consideration. Thus the workers become the active part in the simulation model and the specific models of the involved actors generate the dynamics of the model. The novel approach considers the large scope of decision making for the workers involved in the project. The simulation model is based on a formal description of the elements and their relationships in the form of a meta-model, which is presented in a restricted selection. A verification study serves for the depiction of the closeness of the central model component, the prioritization algorithm, to reality.

Recource-Constrained Project Scheduling Problem: Investigation of the Quality of Project Plans

This paper introduces the results whether humans are able to develop project plans with a high quality for the well-established Multi-criteria Resource-Constrained Project Scheduling Problem (RCPSP). To analyse this, an empirical study was conducted in which activities had to be serialized or parallelized in the plan, process steps had to be inserted or removed and durations as well as resource requirements had to be modified dynamically during planning. In contrast to this human based planning, a specific multicriteria evolutionary metaheuristic is presented that identifies human compatible plans to relatively large project management problems within a reasonable period of time. To evaluate the level of human competitiveness, a metric for measuring plan quality and the results of the empirical study are presented. The results derived from data of 100 participants and the metaheuristic show that only very few people were able to identify optimal solutions. Furthermore, humans are focusing on one target criteria when solving conflicting planning objectives.

Simulation Based Evaluation of Service Science Productivity for Solution Providers

Many companies offer customized solutions by integrating services into their product portfolio. In this regard, a systematic planning for solution providers is crucial, otherwise, task sequences or the assignment of resources to achieve the business objectives can be incorrect. In order to evaluate and to raise the service productivity, service models and simulation techniques have been used to determine the sequence of activities and to assign actors and resources to tasks. In this paper, the authors demonstrate that service solutions can be prospectively modeled, simulated, and optimized. To achieve improved service productivity, the concepts for service productivity are reviewed and a Petri net based simulation approach is introduced. Tests confirm that the simulation approach is capable of calculating a number of service performance metrics that focus on the effect of a stochastic makespan for tasks and the variable assignment of actors and iterations to activities. In the validation study, a service solution process for a power plant construction is considered to analyze the external validity of the simulation model, as well as the structural validity of the corresponding computational models. Simulation results demonstrate the approach providing a convergence to a global optimal service solution.