title: Simplified system dynamics: a methodology for corporate modelling

authors: Craig, Grahame David

abstract: This thesis deals with the development and application of a methodology for constructing corporate planning models. The methodology is based on a framework of general systems concepts consisting of elements from the System Dynamics and Input-Output approaches to the modelling of complex systems. These concepts permit the use of explicit and efficient procedures for constructing corporate planning models, which support each of the conceptual, verbal, graphical and mathematical phases of the model abstraction process. 

Support for the model programming and computational phases is provided by a system of interactive computer programs, written in the ‘BASIC’ language, for a Digital PDP 11/70 timesharing computer. The technical details of these programs and their use, are contained in the Appendices.

Discussion of the methodology is preceded by reviews of both management science and corporate planning, which focus on their respective development histories, future development directions, and their inter-relationship. These reviews provide a foundation for examining the role of computer-based models in corporate planning. In particular, the importance of modelling in resolving the conflicts and problems of corporate planning is established.

Following appraisal of a selection of systems-based modelling methodologies, including System Dynamics, a simplified version of this methodology is presented. This version permits the construction of more open models in which priority is accorded to representation of the structured, mechanistic relationships of the system being modelled.

Introduction of the matrix algebra concepts of Input-Output Analysis enables systems to be represented as vectorised networks, which in turn facilitate the construction of less aggregated models. 

A series of ten applications of the simplified System Dynamics methodology, involving the construction of both financial and non-financial models, is then presented. These applications, together with a comparative study using a typical ‘non-systems’ approach to the construction of a benchmark financial model, provide the basis for assessment of the methodology. This assessment is made in terms of its strengths and weaknesses, and of some recent technological advances in computing. 

As a systems approach to corporate modelling, the methodology is found to meet the needs of corporate planners more closely than any of the existing systems methodologies. The representation of systems as open vectorised networks facilitates model-building and the construction of more flexible, understandable models. These advantages increase markedly as the scale of models constructed with the methodology increases.

The weaknesses of simplified System Dynamics are found to relate directly to the limitations of the current version of the computer software system which supports it. This software system must therefore be upgraded if these weaknesses are to be eliminated. This upgrading should proceed in a manner which takes maximum advantage of the data base management and graphics capabilities of modern time-sharing computers.

text: Simplified system dynamics: a methodology for corporate modelling This thesis deals with the development and application of a methodology for constructing corporate planning models. The methodology is based on a framework of general systems concepts consisting of elements from the System Dynamics and Input-Output approaches to the modelling of complex systems. These concepts permit the use of explicit and efficient procedures for constructing corporate planning models, which support each of the conceptual, verbal, graphical and mathematical phases of the model abstraction process. 

Support for the model programming and computational phases is provided by a system of interactive computer programs, written in the ‘BASIC’ language, for a Digital PDP 11/70 timesharing computer. The technical details of these programs and their use, are contained in the Appendices.

Discussion of the methodology is preceded by reviews of both management science and corporate planning, which focus on their respective development histories, future development directions, and their inter-relationship. These reviews provide a foundation for examining the role of computer-based models in corporate planning. In particular, the importance of modelling in resolving the conflicts and problems of corporate planning is established.

Following appraisal of a selection of systems-based modelling methodologies, including System Dynamics, a simplified version of this methodology is presented. This version permits the construction of more open models in which priority is accorded to representation of the structured, mechanistic relationships of the system being modelled.

Introduction of the matrix algebra concepts of Input-Output Analysis enables systems to be represented as vectorised networks, which in turn facilitate the construction of less aggregated models. 

A series of ten applications of the simplified System Dynamics methodology, involving the construction of both financial and non-financial models, is then presented. These applications, together with a comparative study using a typical ‘non-systems’ approach to the construction of a benchmark financial model, provide the basis for assessment of the methodology. This assessment is made in terms of its strengths and weaknesses, and of some recent technological advances in computing. 

As a systems approach to corporate modelling, the methodology is found to meet the needs of corporate planners more closely than any of the existing systems methodologies. The representation of systems as open vectorised networks facilitates model-building and the construction of more flexible, understandable models. These advantages increase markedly as the scale of models constructed with the methodology increases.

The weaknesses of simplified System Dynamics are found to relate directly to the limitations of the current version of the computer software system which supports it. This software system must therefore be upgraded if these weaknesses are to be eliminated. This upgrading should proceed in a manner which takes maximum advantage of the data base management and graphics capabilities of modern time-sharing computers.

year: 1982

title: Injection-Molding Performance and Mechanical Properties of Blood Meal-Based Thermoplastics

authors: Adamy, Maximilian

subjects: biodegradable

abstract: Protein-based thermoplastics offer an attractive alternative to petroleum-based plastics if their properties allow for large volume production using processes such as injection molding. A fractional factorial design was used to analyze the influence of injection-molding parameters (melt temperature, tool temperature, injection rate, holding pressure, and cooling time) on the injection-molding process (maximum injection pressure, injection pressure curve) and mechanical properties (tensile strength, elongation at break, secant modulus) of blood meal–based thermoplastics. Optimal mechanical properties were obtained at higher tool and melt temperatures while the injection rate was unimportant. The most important injection parameter was the holding pressure, which has to be lowered when using a higher melt temperature, which was preferred for better elongation at break. A lower holding pressure also produced moldings with a higher modulus, which could be good for demolding. Blood meal–based thermoplastics behaved mostly like standard thermoplastics, without any significant deviations. Within a workable processing window, its mechanical properties were largely unaffected by processing conditions, but as with any thermoplastic, care must be taken to select the best injection-molding parameter settings to achieve optimal part quality and high processability.

text: Injection-Molding Performance and Mechanical Properties of Blood Meal-Based Thermoplastics Protein-based thermoplastics offer an attractive alternative to petroleum-based plastics if their properties allow for large volume production using processes such as injection molding. A fractional factorial design was used to analyze the influence of injection-molding parameters (melt temperature, tool temperature, injection rate, holding pressure, and cooling time) on the injection-molding process (maximum injection pressure, injection pressure curve) and mechanical properties (tensile strength, elongation at break, secant modulus) of blood meal–based thermoplastics. Optimal mechanical properties were obtained at higher tool and melt temperatures while the injection rate was unimportant. The most important injection parameter was the holding pressure, which has to be lowered when using a higher melt temperature, which was preferred for better elongation at break. A lower holding pressure also produced moldings with a higher modulus, which could be good for demolding. Blood meal–based thermoplastics behaved mostly like standard thermoplastics, without any significant deviations. Within a workable processing window, its mechanical properties were largely unaffected by processing conditions, but as with any thermoplastic, care must be taken to select the best injection-molding parameter settings to achieve optimal part quality and high processability.

year: 2013

title: Violation of te whare tangata - the maternal body: Young women's journeys through pregnancy and partner terrorism

authors: Marsh, Tuihana M.

subjects: Partner Terrorism

abstract: Partner terrorism is a leading social issue in Aotearoa. It occurs with such frequency and ferocity that it is often considered an epidemic. This has placed us in the shameful position of being the highest ranked nation in the western world for the prevalence of intimate partner violence. This research explored young women’s experiences of intimate partner violence during pregnancy. Eleven women aged 14 - 17 years when pregnant were interviewed. A mana wāhine theoretical perspective was employed, guided by a kaupapa Māori research methodology. Pūrākau was used as a method to present and validate the women’s voices.
The key findings identified that these relationships began with the potential of any other relationship. However, they typically followed a pattern of co-habituation and entrapment through pregnancy and financial dependence. It was evident the partner terrorism was brought into these relationships by the terrorist partners, and was the first experience of this violence for many of the women. The terrorism continued to escalate. Separating from their terrorist partners did not result in the women being any safer, with some continuing to experience life-threatening acts of terrorism post separation. Pregnancy did not serve as a protective factor: the violation of te whare tangata generally occurred before, during and after pregnancy. Often, the acts of terrorism escalated following the birth of their pēpī, with their partner’s terrorism being a direct assault on ūkaipō, disrupting bonding and mothering practices. Many of the women were able to recognise the terrorism to which they were subjected only in hindsight. Despite this, they showed ingenuity and resilience in the ways they resisted the terrorism in efforts to keep themselves and their pēpī safe. Breaking free of these relationships demanded intervention and support from outsiders. The women remain strongly committed to the welfare of their pēpī.

text: Violation of te whare tangata - the maternal body: Young women's journeys through pregnancy and partner terrorism Partner terrorism is a leading social issue in Aotearoa. It occurs with such frequency and ferocity that it is often considered an epidemic. This has placed us in the shameful position of being the highest ranked nation in the western world for the prevalence of intimate partner violence. This research explored young women’s experiences of intimate partner violence during pregnancy. Eleven women aged 14 - 17 years when pregnant were interviewed. A mana wāhine theoretical perspective was employed, guided by a kaupapa Māori research methodology. Pūrākau was used as a method to present and validate the women’s voices.
The key findings identified that these relationships began with the potential of any other relationship. However, they typically followed a pattern of co-habituation and entrapment through pregnancy and financial dependence. It was evident the partner terrorism was brought into these relationships by the terrorist partners, and was the first experience of this violence for many of the women. The terrorism continued to escalate. Separating from their terrorist partners did not result in the women being any safer, with some continuing to experience life-threatening acts of terrorism post separation. Pregnancy did not serve as a protective factor: the violation of te whare tangata generally occurred before, during and after pregnancy. Often, the acts of terrorism escalated following the birth of their pēpī, with their partner’s terrorism being a direct assault on ūkaipō, disrupting bonding and mothering practices. Many of the women were able to recognise the terrorism to which they were subjected only in hindsight. Despite this, they showed ingenuity and resilience in the ways they resisted the terrorism in efforts to keep themselves and their pēpī safe. Breaking free of these relationships demanded intervention and support from outsiders. The women remain strongly committed to the welfare of their pēpī.

year: 2019