Arie Karniel

From DSM-Based Planning to Design Process Simulation: A Review of Process Scheme Logic Verification Issues

Planning product development processes (PDP), and particularly new product development (NPD) processes, is complex and challenging. The plan should reflect the product-related knowledge, including the influences of performing changes in one product component on the need to rework the design of other components. Given the complexity, dynamics, and uncertainties of design processes (DPs), the plan evaluation requires simulation tools. The design structure matrix (DSM) is a known method for DP planning. However, the DSM itself does not express all the relevant information required for defining process logic. Many logic interpretations are applicable in different business cases; yet, a consistent method of transforming a DSM-based plan to a logically correct concurrent process model in the case of iterative activities is lacking. A gap was identified between the literature concerning activities sequencing based on DSM and the process modeling literature concerning process verification. This survey systematically classifies the approaches used in DSM-based process planning, and discusses their strengths and limitations with problems related to process modeling logic verification of iterative processes. Demonstration of the logic differences emphasizes the need for simulation-based decision making according to the specific process attributes.

Decomposing the problem of constrained surface fitting in reverse engineering

Abstract This paper presents a practical solution for surface fitting problems with prioritized geometry constraints in reverse engineering. The approach allows prioritizing constraints and uses them for decomposing the problem into a set of sequentially solved, manageable sub-problems. The result of each solution step is trade-off between satisfying the set of constraints and fitting of the surfaces to the measured points. The overall solution process trades off solution quality with complexity of the problem. Solution quality is checked against pre-defined tolerances assigned to the geometry constraints. Results on a benchmark problem demonstrate the suitability of the approach to solving large problems with hundreds of surfaces and constraints.

Formalizing a Workflow-Net Implementation of Design-Structure-Matrix-Based Process Planning for New Product Development

Many new product development (NPD) projects fail. The NPD context, which incorporates knowledge about the product, requirements, technology, and other factors, is dynamically evolving during the process. Simulations of NPD processes using their specific contexts can provide project managers with decisions-making methods to test their planning. The design structure matrix (DSM) can be used to model the product knowledge; then, reordering algorithms are used for process planning. However, interpretation of the DSM-based plan is not unique, and its translation to a process workflow (WF) model may lead to implementation inconsistencies. WF nets, being a subclass of Petri nets, provide formal tools for verifying process properties. Well handled with Regular Iteration (WRI)-WF nets are a subclass of WF nets that are sound by construction and, therefore, enable an automated process-build approach. This paper presents a formal translation of the DSM-based plan to a process-scheme model, the DSM net, which can be executed and simulated. Using several translation stages, it is proved that the resulting DSM net is equivalent to a WRI-WF net. Therefore, the proposed translation is inherently sound and can be automated, becoming an enabler of implementing evolving product knowledge into a sound changing-process model required for NPD simulations. The presented approach bridges an identified gap between the process-planning community (DSM) and the process-implementation community (Petri net).

Multi-level modelling and simulation of new product development processes

This article presents a multi-level modelling approach for supporting the management of evolving new product development (NPD) processes. Following its articulation, an example of implementing process changes during the development process is presented. Such changes cannot be modelled by existing design/dependency structure matrix (DSM) approaches. A conceptual change in the product design occurs during the development process, in order to standardise the product components, and yields changes in the process plans that are simulated for decision-making. Implementation implications of dynamic changes to a development process are demonstrated, including business rules used to choose between process change options, while considering iteration learning effects. From the demonstration, it becomes clear that either DSM or Petri nets alone do not offer complete modelling capabilities for NPD processes and a multi-level approach must be adopted. Such a complete cycle of modelling would start from product knowledge through the DSM and DSM nets, which are process scheme models, with potentially additional patterns, and would end with a simulation in order to obtain insight into the dynamic changes in the process planning.

Managing the Dynamics of New Product Development Processes

Managing the Dynamics of New-Product Development Processes merges product-based planning, process modelling, process execution, probabilistic simulations, and simulation based decision-making into one framework called the Dynamic new-Product Development Process. It provides readers with a means of improving the management of product development through enhanced methods and tools that are specifically tailored to the characteristics and challenges of such processes. It calls for a new Product Lifecycle Management paradigm of utilizing the managed product data for management of the products development process. Within the framework, the methods used are enhanced or modified to fit the new-product development process requirements.Each specific method is exhaustively analyzed, from the basic definition of terms through a description of the state of the art of that topic and its limitations. Then, the method enhancements are illustrated by many examples, and discussed while suggesting further research directions. Finally, the enhanced methods are integrated and demonstrated by a test case. The main two methods described are the design structure matrix (DSM) and Petri nets, which are merged into a novel concept entitled DSM nets. Managing the Dynamics of New Product Development Processes provides algorithms, proofs, and practical examples that can be used for general study of the issues concerned. The main concepts presented are applicable to systems engineering and can be used by practitioners of product development processes, such as designers, product managers, and process managers, as well as developers of process management tools for systems with dynamically changing process structures.

Dynamic New-Product Design Process

This chapter describes the concepts, methods, and enhancements that compose this research. Due to the variety of subjects, simple examples are added to each issue, as well as simple integrated examples. The implementation of a fully integrated example is presented in Chap. 1.

Interpretation Using Implementation Rules and Business Rules

The interpretation of the DSM to a process scheme is not unique, i.e., the presented links between activities require additional interpretation for translating the DSM into a logically-correct executable process that can be simulated. Implementation Rules are used for interpretation. The Implementation Rules (IR) may have suboptions defined as Business Rules (BR), i.e., they should be chosen according to the business environment and business constraints considerations (e.g., time versus resources).

From DSM to DSM Net

The following sections describe the integration of the DSM planning model with process modeling approaches of Petri netsPetri net. First, the process correctness criteriaCorrectness criteria for the Dynamic new-Product Design Process (DnPDP)Dynamic new-Product Design Process (DnPDP) are presented in Sect. 9.2. Most requirements are adapted from WF-netWF-nets correctness criteriaCorrectness criteria.

Managing Development Processes

Reaching the goal of automating the planning and execution of a DnPDPDynamic new Product Design Process (DnPDP), as well as simulating the process under diverse conditions and decision options is quite complex. It requires the integration of several approaches. The following chapter describes the methods and approaches used, enhanced, and integrated within the suggested DnPDP frameworkDnPDP framework.

Process Modeling Using Workflow-Nets

Once a project plan is set, various methods can be used for its implementation. The previously reviewed DSM based simulations do not use a formal method for implementing the process model. Such methods include proprietary workflow models, graphical evaluation and review technique Graphical Evaluation and Review Technique (GERT), Task netsTask net, pi-calculus, and Petri netsPetri net (discussed in the next section).For its implementation, the process is defined by the Process schemeProcess scheme model representing the precedence relations in addition to process logic. Generalized precedence relations Generalized Precedence Relations (GPR) (Elmaghraby, Eur J Oper Res, 82:383–408, 1995) include the typical end–start relations, start–start, end–end, and iterations (cycles). The overlapOverlap relation was defined in Cho and Eppinger Conf on (DECT 2001/DTM), as a start–start relation with delay. The relations are implemented by defining the Input Logic of an activity (pre-conditions) and the Output Logic (post-conditions).