An Empirical Comparison of Reuse in Embedded and Nonembedded Systems

High-quality software, delivered on time and budget, constitutes a critical part of most products and services in modern society. Our government has invested billions of dollars to develop software assets, often to redevelop the same capability many times. Recognizing the waste involved in redeveloping these assets, in 1992 the Department of Defense issued the Software Reuse Initiative. The vision of the Software Reuse Initiative was "To drive the DoD software community from its current "re-invent the software" cycle to a process-driven, domain-specific, architecture-centric, library-based way of constructing software.'' Twenty years after issuing this initiative, there is evidence of this vision beginning to be realized in nonembedded systems. However, virtually every large embedded system undertaken has incurred large cost and schedule overruns. Investigations into the root cause of these overruns implicates reuse. Why are we seeing improvements in the outcomes of these large scale nonembedded systems and worse outcomes in embedded systems? This question is the foundation for this research. The experiences of the Aerospace industry have led to a number of questions about reuse and how the industry is employing reuse in embedded systems. For example, does reuse in embedded systems yield the same outcomes as in nonembedded systems? Are the outcomes positive? If the outcomes are different, it may indicate that embedded systems should not use data from nonembedded systems for estimation. Are embedded systems using the same development approaches as nonembedded systems? Does the development approach make a difference? If embedded systems develop software differently from nonembedded systems, it may mean that the same processes do not apply to both types of systems. What about the reuse of different artifacts? Perhaps there are certain artifacts that, when reused, contribute more or are more difficult to use in embedded systems. Finally, what are the success factors and obstacles to reuse? Are they the same in embedded systems as in nonembedded systems? The research in this dissertation is comprised of a series of empirical studies using professionals in the aerospace and defense industry as its subjects. The main focus has been to investigate the reuse practices of embedded systems professionals and nonembedded systems professionals and compare the methods and artifacts used against the outcomes. The research has followed a combined qualitative and quantitative design approach. The qualitative data were collected by surveying software and systems engineers, interviewing senior developers, and reading numerous documents and other studies. Quantitative data were derived from converting survey and interview respondents' answers into coding that could be counted and measured. From the search of existing empirical literature, we learned that reuse in embedded systems are in fact significantly different from nonembedded systems, particularly in effort in model based development approach and quality where the development approach was not specified. The questionnaire showed differences in the development approach used in embedded projects from nonembedded projects, in particular, embedded systems were significantly more likely to use a heritage/legacy development approach. There was also a difference in the artifacts used, with embedded systems more likely to reuse hardware, test products, and test clusters. Nearly all the projects reported using code, but the questionnaire showed that the reuse of code brought mixed results. One of the differences expressed by the respondents to the questionnaire was the difficulty in reuse of code for embedded systems when the platform changed. The semistructured interviews were performed to tell us why the phenomena in the review of literature and the questionnaire were observed. We asked respected industry professionals, such as senior fellows, fellows and distinguished members of technical staff, about their experiences with reuse. We learned that many embedded systems used heritage/legacy development approaches because their systems had been around for many years, before models and modeling tools became available. We learned that reuse of code is beneficial primarily when the code does not require modification, but, especially in embedded systems, once it has to be changed, reuse of code yields few benefits. Finally, while platform independence is a goal for many in nonembedded systems, it is certainly not a goal for the embedded systems professionals and in many cases it is a detriment. However, both embedded and nonembedded systems professionals endorsed the idea of platform standardization. Finally, we conclude that while reuse in embedded systems and nonembedded systems is different today, they are converging. As heritage embedded systems are phased out, models become more robust and platforms are standardized, reuse in embedded systems will become more like nonembedded systems.

Torn between state and market: Private policy implementation and conflicting institutional logics

Policy implementation by private actors constitutes a “missing link” for understanding the implications of private governance. This paper proposes and assesses an institutional logics framework that combines a top-down, policy design approach with a bottom-up, implementation perspective on discretion. We argue that the conflicting institutional logics of the state and the market, in combination with differing degrees of goal ambiguity, accountability and hybridity play a crucial role for output performance. These arguments are analyzed based on a secondary analysis of seven case studies of private and hybrid policy implementation in diverging contexts. We find that aligning private output performance with public interests is at least partly a question of policy design congruence: private implementing actors tend to perform deficiently when the conflicting logics of the state and the market combine with weak accountability mechanisms.

Urban Crematoria: Reinventing the Architecture of Death

Thesis (Master's)--University of Washington, 2016-04

An Electromechanical Coupled Model of the Probe of a Scanning Fiber Imaging System

Thesis (Master's)--University of Washington, 2016-06

A novel phantom and method for comprehensive 3-dimensional measurement and correction of geometric distortion in magnetic resonance imaging

A phantom that can be used for mapping geometric distortion in magnetic resonance imaging (MRI) is described. This phantom provides an array of densely distributed control points in three-dimensional (3D) space. These points form the basis of a comprehensive measurement method to correct for geometric distortion in MR images arising principally from gradient field non-linearity and magnet field inhomogeneity. The phantom was designed based on the concept that a point in space can be defined using three orthogonal planes. This novel design approach allows for as many control points as desired. Employing this novel design, a highly accurate method has been developed that enables the positions of the control points to be measured to sub-voxel accuracy. The phantom described in this paper was constructed to fit into a body coil of a MRI scanner, (external dimensions of the phantom were: 310 mm x 310 mm x 310 mm), and it contained 10,830 control points. With this phantom, the mean errors in the measured coordinates of the control points were on the order of 0.1 mm or less, which were less than one tenth of the voxel's dimensions of the phantom image. The calculated three-dimensional distortion map, i.e., the differences between the image positions and true positions of the control points, can then be used to compensate for geometric distortion for a full image restoration. It is anticipated that this novel method will have an impact on the applicability of MRI in both clinical and research settings. especially in areas where geometric accuracy is highly required, such as in MR neuro-imaging. (C) 2004 Elsevier Inc. All rights reserved.

Cost-exergy optimisation of linear Fresnel reflectors

This paper presents a new method for the optimisation of the mirror element spacing arrangement and operating temperature of linear Fresnel reflectors (LFR). The specific objective is to maximise available power output (i.e. exergy) and operational hours whilst minimising cost. The method is described in detail and compared to an existing design method prominent in the literature. Results are given in terms of the exergy per total mirror area (W/m2) and cost per exergy (US $/W). The new method is applied principally to the optimisation of an LFR in Gujarat, India, for which cost data have been gathered. It is recommended to use a spacing arrangement such that the onset of shadowing among mirror elements occurs at a transversal angle of 45°. This results in a cost per exergy of 2.3 $/W. Compared to the existing design approach, the exergy averaged over the year is increased by 9% to 50 W/m2 and an additional 122 h of operation per year are predicted. The ideal operating temperature at the surface of the absorber tubes is found to be 300 °C. It is concluded that the new method is an improvement over existing techniques and a significant tool for any future design work on LFR systems

Flexible high speed machinery

The thesis describes an investigation into methods for the design of flexible high-speed product processing machinery, consisting of independent electromechanically actuated machine functions which operate under software coordination and control. An analysis is made of the elements of traditionally designed cam-actuated, mechanically coupled machinery, so that the operational functions and principal performance limitations of the separate machine elements may be identified. These are then used to define the requirements for independent actuators machinery, with a discussion of how this type of design approach is more suited to modern manufacturing trends. A distributed machine controller topology is developed which is a hybrid of hierarchical and pipeline control. An analysis is made, with the aid of dynamic simulation modelling, which confirms the suitability of the controller for flexible machinery control. The simulations include complex models of multiple independent actuators systems, which enable product flow and failure analyses to be performed. An analysis is made of high performance brushless d.c. servomotors and their suitability for actuating machine motions is assessed. Procedures are developed for the selection of brushless servomotors for intermittent machine motions. An experimental rig is described which has enabled the actuation and control methods developed to be implemented. With reference to this, an evaluation is made of the suitability of the machine design method and a discussion is given of the developments which are necessary for operational independent actuators machinery to be attained.

Adaptive congestion control for DSRC vehicle networks

Dedicated short range communications (DSRC) was proposed for collaborative safety applications (CSA) in vehicle communications. In this article we propose two adaptive congestion control schemes for DSRC-based CSA. A cross-layer design approach is used with congestion detection at the MAC layer and traffic rate control at the application layer. Simulation results show the effectiveness of the proposed rate control scheme for adapting to dynamic traffic loads.

Exploring the experiences of nurses who care for children who have Acute Life Threatening Events (ALTE) in hospital

This thesis presents a program of work designed to explore and describe what the experience of caring for a child who has an Acute Life Threatening Event (ALTE) is like for the nurses. An ALTE may include a cardiac arrest, respiratory arrest or unplanned admission for a ward to the Paediatric Intensive Care unit. Using the MRC framework for the development of complex interventions, this information was then coupled with theory to develop the PREPARE and SUPPORT interventions. Given the wide-ranging and exploratory nature of this research, a pragmatic, mixed design approach was used to address the aims and objectives of the thesis. The mixed design approach included: a systematic literature review; international survey of practice; interviews with nurses and doctors using Interpretative Phenomenological Analysis; development, refinement and evaluation of interventions during a feasibility study. Two studies were identified through the systematic review which aimed to evaluate the effectiveness of debriefing. The studies did not provide evidence to support the use of these interventions within healthcare. The international survey of practice demonstrated hospitals were using interventions to both prepare and support nurses for these events. The preparatory interventions were clinically focused and the majority of the supportive interventions included a debrief. The interventions were not being evaluated for effectiveness. The interviews conducted with nurses and doctors provided insight into what that experience was like for the participants. Using the MRC framework, this evidence was coupled with theory to develop the PREPARE and SUPPORT interventions. A multidisciplinary working party used an iterative process to refine and evaluate the interventions and study procedures were explored through a feasibility study. The pragmatic, mixed design approach demonstrated how the empirical evidence was coupled with theory and clinical expertise to develop interventions for use within the healthcare environment.

Undergraduate research training and graduate recruitment

Purpose – Formal opportunities for psychology undergraduates to carry out research training are starting to emerge. In spite of the fact that such training programmes would have a high authentic learning component little is known of undergraduate expectations and attitudes towards such programmes. This paper aims to focus on the issues. Methodology/design/approach – In total, 108 undergraduate participants were surveyed in two experiments that recorded both the prospective and retrospective attitudes towards research training participation. Questionnaires and focus groups were employed and the data were triangulated together to converge on an understanding of student expectations towards authentic learning programmes. Findings – While psychology undergraduates expect to be trained in contemporary research techniques it is the sense of community development that is the prime motivator for participation. Originality/value – The paper places these findings within the context of increasing the employability profile of the undergraduate cohort.

Older adults with AMD as co-designers of an assistive mobile application

In the UK, 20% of people aged 75 years and over are living with sight loss and age-related macular degeneration (AMD) is the most common cause of sight loss in the UK, impacting nearly 10% of those over 80; regrettably, these fgures are expected to increase in coming decades as the population ages (RNIB, 2012). This paper reports on the authors' design activities conducted for the purpose of informing the development of an assistive self-monitoring, ability-reactive technology (SMART) for older adults with AMD. The authors refect on their experience of adopting and adapting the PICTIVE (Plastic Interface for Collaborative Technology Initiatives through Video Exploration) participatory design approach (Muller, 1992) to support effective design with and for their special needs user group, refect on participants' views of being part of the process, and discuss the design themes identifed via their PD activities.

Themed Issue on Mobile HCI @ iHCI

In the UK, 20% of people aged 75 years and over are living with sight loss and age-related macular degeneration (AMD) is the most common cause of sight loss in the UK, impacting nearly 10% of those over 80; regrettably, these figures are expected to increase in coming decades as the population ages (RNIB, 2012). This paper reports on the authors' design activities conducted for the purpose of informing the development of an assistive self-monitoring, ability-reactive technology (SMART) for older adults with AMD. The authors reflect on their experience of adopting and adapting the PICTIVE (Plastic Interface for Collaborative Technology Initiatives through Video Exploration) participatory design approach (Muller, 1992) to support effective design with and for their special needs user group, reflect on participants' views of being part of the process, and discuss the design themes identified via their PD activities.

Development of a new client -server architecture for context aware mobile computing

This dissertation studies the context-aware application with its proposed algorithms at client side. The required context-aware infrastructure is discussed in depth to illustrate that such an infrastructure collects the mobile user’s context information, registers service providers, derives mobile user’s current context, distributes user context among context-aware applications, and provides tailored services. The approach proposed tries to strike a balance between the context server and mobile devices. The context acquisition is centralized at the server to ensure the reusability of context information among mobile devices, while context reasoning remains at the application level. Hence, a centralized context acquisition and distributed context reasoning are viewed as a better solution overall. The context-aware search application is designed and implemented at the server side. A new algorithm is proposed to take into consideration the user context profiles. By promoting feedback on the dynamics of the system, any prior user selection is now saved for further analysis such that it may contribute to help the results of a subsequent search. On the basis of these developments at the server side, various solutions are consequently provided at the client side. A proxy software-based component is set up for the purpose of data collection. This research endorses the belief that the proxy at the client side should contain the context reasoning component. Implementation of such a component provides credence to this belief in that the context applications are able to derive the user context profiles. Furthermore, a context cache scheme is implemented to manage the cache on the client device in order to minimize processing requirements and other resources (bandwidth, CPU cycle, power). Java and MySQL platforms are used to implement the proposed architecture and to test scenarios derived from user’s daily activities. To meet the practical demands required of a testing environment without the impositions of a heavy cost for establishing such a comprehensive infrastructure, a software simulation using a free Yahoo search API is provided as a means to evaluate the effectiveness of the design approach in a most realistic way. The integration of Yahoo search engine into the context-aware architecture design proves how context aware application can meet user demands for tailored services and products in and around the user’s environment. The test results show that the overall design is highly effective, providing new features and enriching the mobile user’s experience through a broad scope of potential applications.

Study of Periodic and Quasi-Periodic Structures in Silicon-on-Insulator

In this thesis, a numerical design approach has been proposed and developed based on the transmission matrix method in order to characterize periodic and quasi-periodic photonic structures in silicon-on-insulator. The approach and its performance have been extensively tested with specific structures in 2D and its validity has been verified in 3D.

Development of a New Client-Server Architecture for Context Aware Mobile Computing

This dissertation studies the context-aware application with its proposed algorithms at client side. The required context-aware infrastructure is discussed in depth to illustrate that such an infrastructure collects the mobile user’s context information, registers service providers, derives mobile user’s current context, distributes user context among context-aware applications, and provides tailored services. The approach proposed tries to strike a balance between the context server and mobile devices. The context acquisition is centralized at the server to ensure the usability of context information among mobile devices, while context reasoning remains at the application level. Hence, a centralized context acquisition and distributed context reasoning are viewed as a better solution overall. The context-aware search application is designed and implemented at the server side. A new algorithm is proposed to take into consideration the user context profiles. By promoting feedback on the dynamics of the system, any prior user selection is now saved for further analysis such that it may contribute to help the results of a subsequent search. On the basis of these developments at the server side, various solutions are consequently provided at the client side. A proxy software-based component is set up for the purpose of data collection. This research endorses the belief that the proxy at the client side should contain the context reasoning component. Implementation of such a component provides credence to this belief in that the context applications are able to derive the user context profiles. Furthermore, a context cache scheme is implemented to manage the cache on the client device in order to minimize processing requirements and other resources (bandwidth, CPU cycle, power). Java and MySQL platforms are used to implement the proposed architecture and to test scenarios derived from user’s daily activities. To meet the practical demands required of a testing environment without the impositions of a heavy cost for establishing such a comprehensive infrastructure, a software simulation using a free Yahoo search API is provided as a means to evaluate the effectiveness of the design approach in a most realistic way. The integration of Yahoo search engine into the context-aware architecture design proves how context aware application can meet user demands for tailored services and products in and around the user’s environment. The test results show that the overall design is highly effective,providing new features and enriching the mobile user’s experience through a broad scope of potential applications.