Sheared Interpolation and Gradient Estimation for Real-Time Volume Renderings

In this paper we present a technique for the interactive control and display of static and dynamic 3D datasets. We describe novel ways of tri-linear interpolation and gradient estimation for a real-time volume rendering system, using coherency between rays. We show simulation results that compare the proposed methods to traditional algorithms and present them in the context of Cube-3, a special-purpose architecture capable of rendering 5123 16-bit per voxel datasets at over 20 frames per second.Engineering and Applied Science

Towards a Scalable Architecture for Real-Time Volume Rendering

In this paper we present our research eff orts towards a scalable volume rendering architecture for the real-time visualization of dynamically changing high-resolution datasets. Using a linearly skewed memory interleaving we were able to develop a parallel data ow model that leads to local, fixed-bandwidth interconnections between processing elements. This parallel dataflow model diff ers from previous work in that it requires no global communication of data except at the pixel level. Using this data ow model we are developing Cube-4, an architecture that is scalable to very high performances and allows for modular and extensible hardware implementations.Engineering and Applied Science

The development of complex systems : an integrated approach to design influencing

The aim of this research is to identify and analyze the impact of design changes to a system in a concurrent engineering environment and the development project, and to make proposals how to minimize the impact on the development project performance. A further objective is also to determine the effect of design changes as a result of design influencing. In a concurrent engineering environment system components are being developed in parallel. Any change to one component of the system may impact on other system components under development. Design as part of the systems engineering process is an iterative and dynamic process. Although the systems engineering process has been very well structured and refined over the years, it still remains to a certain extent an unpredictable process. A consequence of this is that changes to a design of a subsystem or component comprising the system can occur at any stage of the process. The systems engineering process is a “static” process since there are no time constraints or management of consumption of resources on the different systems engineering processes and steps. As such system engineering cannot function in isolation. To bring a system into being, systems engineering must function within a project management environment to provide the management of schedule and the consumption of resources. The interaction between project management and system engineering processes can have a distinct influence on the systems engineering process and must be taken into account when studying the performance of system development projects. This research investigates the project management/systems engineering interface with specific focus on cost and schedule. Since project management is the encompassing process wherein a system is being developed, its influence on the system engineering process will also be investigated. This research has the following research objectives: Optimization of design influencing by dividing the design teams into two different complementary but opposing mindset groups. Evaluate the impact of design changes in terms of cost and schedule overruns in a concurrent engineering development environment. A comprehensive development project was used as a case-study. A Narrative Inquiry comprising the main system development project players investigated the problems experienced on the project and found that management was the major cause for the project cost and schedule overruns. The principal finding of this research showed, that unplanned, unexpected and forced design changes was the primary area of conflict between systems engineering and project management, leading to development project cost and schedule overruns. The Narrative Inquiry findings were actually the symptoms of a deeper underlying problem. Root Cause analysis identified the fundamental mechanisms of design change and the influence of management on the process. This research identifies the fundamental mechanisms that result in design iterations and the influence that management has on this process. An improved “Effect-to-Cause” design influencing model is proposed to reduce the risk of design changes during system integration. A mathematical model has been developed to quantify the impact of a design change on a multi-layer, multi-component system. This model confirms that the system hierarchy design is very important to minimize the impact and consequential development project risk should a design change be required for one of the system components. By means of the mathematical model, a proposed system’s architecture can be modelled. The model quantifies the impact of a system component design change on the rest of the system development project. This model will facilitate the optimization of system architecture to reduce development project cost and schedule risks. The system architecture model will also enable design review boards to make informed decisions when considering options for a system component design change. This research also found that the Systems Engineering process must function harmoniously within the larger Project Management environment for the optimum performance of a development project. The road forward to achieve this goal is for the systems engineering and design processes to become more structured and the removal of the unpredictability in the processes so far as the number of design iterations is concerned. This will enable the systems engineering processes to be more easily accommodated within the structured project management processes to the benefit of the overall development project performance. A structured “Cause-to-Effect” design influencing methodology has been investigated. Indications are that this may be the road forward for systems engineering process development to even further reduce the risk of a design change during system integration and consequential detrimental impact on the development project performance.Thesis (PhD)--University of Pretoria, 2012.Graduate School of Technology Management (GSTM)unrestricte

An integrated process framework for engineering endeavours

With the exponential increase in the complexity of modern products, the enterprise which creates the product also increases in complexity. Projects to realise engineering products are often fraught with delays, budget overruns and unsatisfied clients. The study sets out exploring the domains of systems engineering, project management and quality management, by extensively referencing industry standards and international good practice in the quest of unravelling conflicts and uncertainties. Selected concepts and business processes of each domain are studied to arrive at an understanding of the objectives and scopes of those processes. This understanding enables the integration of these business processes and concepts by utilising the widely‐used plan‐do‐check‐act (PDCA) cycle. The business processes of each domain are divided into the four PDCA quadrants and integrated models of those quadrants are presented. The four quadrants are synthesised into a single framework which shows the project management, quality management and systems engineering processes performed during a single project phase. This Engineering Management Framework may be tailored for the design and realisation of any complex product, given adequate planning, understanding of the challenges and knowledge of the subject matter

An improved fundamental design influencing methodology in a constrained project management environment

The aim of this paper is to develop conceptually from literature an improved design influencing concept in a constrained project management environment. The project management and systems engineering interface pertaining to project cost and schedule has been researched. Design as part of Systems Engineering (SE) and Project Management (PM) is an important process for product development. The interaction between SE and PM can influence the success of a product development project. A model has been developed to better understand why design iterations are fundamental to the design process. This model has been expanded into a constrained design influencing model that provides a better understanding of the influence of project management in the design process. This model shows that the project manager, particularly if he is under unrealistic constraints, can force a premature design release for integration to the next system level. This model helps to provide a fundamental understanding of the design process.http://www.saiee.org.za/Default.aspxam201

Glial fibrillary acidic protein and multiple sclerosis progression independent of acute inflammation

Background: The clinical relevance of serum glial fibrillary acidic protein (sGFAP) concentration as a biomarker of MS disability progression independent of acute inflammation has yet to be quantified.// Objective: To test whether baseline values and longitudinal changes in sGFAP concentration are associated with disability progression without detectable relapse of magnetic resonance imaging (MRI) inflammatory activity in participants with secondary-progressive multiple sclerosis (SPMS).// Methods: We retrospectively analyzed longitudinal sGFAP concentration and clinical outcome data from the Phase 3 ASCEND trial of participants with SPMS, with no detectable relapse or MRI signs of inflammatory activity at baseline nor during the study (n = 264). Serum neurofilament (sNfL), sGFAP, T2 lesion volume, Expanded Disability Status Scale (EDSS), Timed 25-Foot Walk (T25FW), 9-Hole Peg Test (9HPT), and composite confirmed disability progression (CDP) were measured. Linear and logistic regressions and generalized estimating equations were used in the prognostic and dynamic analyses.// Results: We found a significant cross-sectional association between baseline sGFAP and sNfL concentrations and T2 lesion volume. No or weak correlations between sGFAP concentration and changes in EDSS, T25FW, and 9HPT, or CDP were observed.// Conclusion: Without inflammatory activity, changes in sGFAP concentration in participants with SPMS were neither associated with current nor predictive of future disability progression./

The management of reliability in a multi-level support environment

M.Ing.In this thesis aspects of reliability management in a multi-level support environment are researched. Complex systems are generally supported over a number of support levels due to the specialist nature and support infrastructure requirements of the individual subsystems. Such a support approach also ensures optimum availability of the system whilst the subsystems are still in the repair cycle. Once a new system is put into service, it is exposed to the actual operational environment and not the simulated environment that was used to qualify the system during its development. In the operational environment, the system is also exposed to the support infrastructure. These factors, as well as any latent design and production defects, impair the achieved operational reliability of such a system. False removals and premature failures after a repair action further degrade the actual operational reliability of the system. It is generally not possible to qualify the logistic support infrastructure fully before placing a new system into operational service. Support stabilisation should take place early on in the support phase of such a system to correct all latent defects and deficiencies of any of the logistic elements required to support the system. Any latent design and production process defects not eradicated from the system will also surface during the support stabilisation period. Support stabilisation will ensure a constant failure rate for the operational life of the system at the lowest life-cycle cost. The methodology used to achieve system reliability growth during the support phase is similar to reliability growth during the development phase. However, additional variables of the operational and support environment are now included in the reliability growth process. The process is also further compounded by the geographic separation of the different levels of support each generally with their own support management infrastructure. The proposed approach is: get total management commitment and close the management loop over the different levels of support. establish the root cause of every system failure implement a test, analyse and fix policy eliminate ineffective repair actions ensure that the system operational environment is within the system specification remove latent design defects from the system correct deficiencies in the logistic elements

Towards a Scalable Architecture for Real-Time Volume Rendering

In this paper we present our research efforts towards a scalable volume rendering architecture for the real-time visualization of dynamically changing high-resolution datasets. Using a linearly skewed memory interleaving we were able to develop a parallel dataflow model that leads to local, fixed-bandwidth interconnections between processing elements. This parallel dataflow model differs from previous work in that it requires no global communication of data except at the pixel level. Using this dataflow model we are developing Cube-4, an architecture that is scalable to very high performances and allows for modular and extensible hardware implementations. 1 Introduction Volume visualization has become a key technology in the interpretation of the large amounts of volumetric data generated by acquisition devices such as biomedical scanners, by supercomputer simulations, or by synthesizing (voxelizing) geometrical models using volume graphics techniques [9, 11]. It encompasses an array..

Sheared Interpolation and Gradient Estimation for Real-Time Volume Rendering

In this paper we present a technique for the interactive control and display of static and dynamic 3D datasets. We describe novel ways of tri-linear interpolation and gradient estimation for a real-time volume rendering system, using coherency between rays. We show simulation results that compare the proposed methods to traditional algorithms and present them in the context of Cube-3, a special-purpose architecturecapable of rendering 512³ 16-bit per voxel datasets at over 20 frames per second