| 31281. |
- Martínez-Ávila, Carlos
(författare)
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Stakeholder Participation in Property Development
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The traditional representation of urban property as a technical exercise of market analysis, valuation and investment appraisal fails to link urban property development to the general notions of sustainable development and thus the connection to environmental, economic and social aspects of sustainable urban development. Knowledge of the social processes in the production and use of the built environment, specifically in land and property development processes, is vital to understand the complexity of urban development and thus to assist the management of urban development processes. A key aspect to the social production of urban property development is the understanding of the relationship between the strategies, interests and actions of the various actors involved in the development process and the economic and socio-political context, which frames their decision-making. Moreover, the implementation of urban property development projects involves and affects a wide range of stakeholders with different attributes, interests, needs and concerns who hold the capacity to influence the project negatively or positively. Inadequate management of the concerns of stakeholders can lead to controversy and conflict about the implementation of the project. Community attitudes are one example that has been shown to be an important factor when planning for, and locating, a development project. The demands of different stakeholder groups vary and a project can benefit one stakeholder group whilst simultaneously having a negative impact on others. Thus, accommodating the various stakeholders’ needs and concerns as well as balancing their differences, conflicts and power relations is vital for the successful implementation of sustainable urban property development projects. The aim of this research was to acquire a deeperunderstanding of stakeholder participation in the early stages of property development as well as to contribute to the conceptualization of stakeholder participation in property development. A qualitative research strategy was chosen with case study and participatory action research as the main research methods. Four cases were conducted through participant observations, workshops, interviews, questionnaire, field notes and document analysis. The findings reveal that stakeholder participation in property development is an emerging practice,however, proactive actions to stakeholder participation remain at the individual level rather than an organizational or institutional level. However, if supported, these practices have the potential to influence the work of organizations and further contribute to sustainable urban property development. This researchcontributes to the conceptualization of stakeholder participation in property development by proposing a systematic framework for stakeholder participation in propery development projects.The framework contains a set of guiding principles and steps that can guide project managers to plan and implement stakeholder participation processes.
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| 31282. |
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| 31283. |
- Martinez, Carolina
(författare)
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Targeting Children Online : Young internet users and producers in the commercial media environment
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Children’s daily internet usage takes place to a large extent in a commercial environment, where advertising and the sale of virtual goods are ever-present parts of the online experience. The overall goal of this thesis is to contribute to a critical understanding of children’s commercial online environment as spaces for children’s everyday life activities and participation, and as spaces for commercial interests that seek to target children and monetize their internet usage. Two papers analyze the perspectives of children, namely, how children view and engage with online advertising. Two papers explore the perspectives of producers involved in advertising to children online, with a focus on how these producers represent themselves, their practices and the child audience. In addition to this, one paper analyzes what participatory opportunities are provided to users in children’s virtual worlds, and how participation is constrained by the commercial strategies (the sale of virtual goods and VIP membership). This paper also looks into the ways in which the producer discursively represents the virtual world, and how the users relate tactically to the commercial strategies. The empirical material includes 20 individual interviews with 9-year-old children, 12 group interviews (in total 46 participants) with 9- and 12-year-old children, as well as interviews with 18 marketers and advertising agency professionals. The case study of the virtual world Habbo Hotel includes online observations, one producer interview and document analysis. The thesis combines different theoretical perspectives that mainly are productive for understanding the subjectivities and practices of children and producers. Michel de Certeau’s (1984) theory on practices in everyday life is of special importance in the thesis and is used in three of the papers. The results show the mulitiplicity and ambivalence of children’s practices with regard to online advertising; the children engaged tactically with advertising through different forms of avoidance tactics and “tactics of the mind” (such as critique), and the children also expressed how they engaged non-tactically with advertising, such as sitting and watching advertisements without wanting to. They primarily considered advertising as an intruder that obstructed their internet usage, and which introduced moments of struggle, deception, confrontation and resignation. However, advertising was also engaged with as entertainment and information. These results suggest that the commercial online environment, particularly advertising-based mobile games, is a demanding environment for children. The case study of the virtual world Habbo Hotel reveals, among other things, how the producer’s main strategy was to provide rather unrestricted opportunities for social participation, and based on that market virtual goods and VIP membership through methods that, for instance, took advantage of children’s need to gain status in the peer group. The producer-oriented study shows how the advertising producers discursively evaded the power relationship existing between them and the child audience; they either refuted or distanced themselves from the subject position “producer of child-directed advertising” and legitimized their practices by arguing that their advertisements were directed to, for instance, parents and the family, or by downplaying the marketing dimension of branded entertainment. Children were constructed in ambivalent ways, as both vulnerable and incompetent, and as competent and dependent. These results contribute to our understanding of how cultural context shapes the notion of the child audience among producers.
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| 31284. |
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| 31285. |
- Martinez, David
(författare)
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Design, Modelling and Control of Electrical Machines - With Applications to Iron-powder Machines and Acoustic Noise
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis consists of two parts, the first dealing with the design of iron-powder synchronous machines, and the second with the analysis and prediction of the acoustic noise in electrical machines. In Part I, a 1.6 kW electrically magnetized claw-pole machine with magnetically conducting end-plates has been analyzed and a prototype tested. The machine is built from soft magnetic composite material (SMC), also known as iron-powder. The magnetic isotropy of SMC gives enormous flexibility in electrical machine design, enabling new topologies exploiting three dimensional flux paths. This is the main advantage compared to conventional machines using laminations, where the flux is constrained into two dimensions. The novelty of the machine presented lies in that the slip-rings in the rotor are no longer needed, since the field coils are removed from the rotor and placed in magnetically conducting end-plates attached to both sides of the stator. This also improves the cooling capability of the copper losses from the field winding, allowing an increased electric loading. The rotor is of the claw-pole type, and the end-plates close the magnetic circuit between the stator and the rotor. The machine has been optimized using a magnetic equivalent circuit model allowing rotation, where non-linearities have been included using an iterative approach based on the linearisation of the BH curve. The traditional leakage paths in claw-pole machines are modified because of the magnetically conducting end-plates, and alternatives are proposed to reduce them. The machine has also been compared to two alternative topologies with electrical magnetization and another with permanent magnets. In Part II, the measurement and prediction of the noise emissions from induction motors using the vector control technique is analyzed together with some structural changes to reduce these emissions. A drive system has been developed for a 2.2 kW induction motor, and its dynamic capabilities demonstrated for a wide range of the frequency spectrum. This tool has been used for the experimental evaluation of the noise emissions when the flux and/or the torque are modulated with high frequency noise signals. The results showed that the noise emissions were higher when the flux was modulated compared to the torque, although the differences were considerably reduced when the machine was loaded. It was also observed that the noise emissions were decreased importantly at load. Sound pressure and sound intensity measurements have been conducted with the rotor stationary and rotating at low speed, showing that the most proper way to quantify the noise emissions from electric machinery is to measure the sound power. A method for the prediction of the noise emissions has been proposed, based on the interactive use of commercial packages for mechanical, electromagnetic and acoustic analyses based in the finite and boundary element methods. Finally, a study has been conducted to assess the effectiveness of introducing peripheral air gap layers around the stator core to reduce the noise emissions.
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| 31286. |
- Martinez, David
(författare)
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Spherical Machines: A Literature Review
- 2005
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report contains a summary of the work with spherical electrical machines found in the specialised literature. Spherical actuators allow several degrees of freedom (DOF), which is particularly interesting in robotics. Complex movements are traditionally accomplished by combining several electrical machines with 1-DOF, ending up with an overweight actuator and accuracy problems due to tolerances. The research into multidegree-of-freedom actuators has been ongoing for decades, the first designs dating from the late 1950’s. However, competitive performance has not been achieved until power electronics and digital signal processors were incorporated in the controls, and therefore the literature reviewed in this report is mainly limited to the contributions done in the last decade. The report is mainly focused on the configurations presenting 3-DOF which have been successfully implemented in practice, although other potential topologies and 2-DOF systems are also reviewed.
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| 31287. |
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| 31288. |
- Martins, Alexandre
(författare)
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Resource Management in Distributed Camera Systems
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this work is to investigate different methods to solve the problem of allocating the correct amount of resources (network bandwidth and storage space) to video camera systems. Here we explore the intersection between two research areas: automatic control and game theory. Camera systems are a good example of the emergence of the Internet of Things (IoT) and its impact on our daily lives and the environment. We aim to improve today’s systems, shift from resources over-provisioning to allocate dynamically resources where they are needed the most. We optimize the storage and bandwidth allocation of camera systems to limit the impact on the environment as well as provide the best visual quality attainable with the resource limitations. This thesis is written as a collection of papers. It begins by introducing the problem with today’s camera systems, and continues with background information about resource allocation, automatic control and game theory. The third chapter de- scribes the models of the considered systems, their limitations and challenges. It then continues by providing more background on the automatic control and game theory techniques used in the proposed solutions. Finally, the proposed solutions are provided in five papers.Paper I proposes an approach to estimate the amount of data needed by surveillance cameras given camera and scenario parameters. This model is used for calculating the quasi Worst-Case Transmission Times of videos over a network. Papers II and III apply control concepts to camera network storage and bandwidth assignment. They provide simple, yet elegant solutions to the allocation of these resources in distributed camera systems. Paper IV com- bines pricing theory with control techniques to force the video quality of cam- era systems to converge to a common value based solely on the compression parameter of the provided videos. Paper V uses the VCG auction mechanism to solve the storage space allocation problem in competitive camera systems. It allows for a better system-wide visual quality than a simple split allocation given the limited system knowledge, trust and resource constraints.
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| 31289. |
- Martins, Igor
(författare)
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An Act for the Abolition of the Slave Trade : The effects of an import ban on Cape Colony slaveholders
- 2019
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Few could have foreseen the consequences when the British Parliament, in 1807, passed the Slave Trade Act that sought to abolish slave imports into the British Empire. From population decreases in the British Caribbean to increased prices in the Cape Colony, historical evidence suggests that the effects of the Act were felt far and wide even though commercialization of slaves was still possible within colonial territories. Using newly digitized historical datasets covering more than 40 years in two different districts of the British Cape Colony, this paper measures changes in slave ownership and acquisition patterns from a longitudinal perspective. This approach allows me to tease out the effects of the Act on farmers with different types of agricultural outputs, most notably crop and livestock farming, agricultural types with very different labor demands. The results show that livestock farmers, surprisingly, were more inelastic to the import ban in comparison to crop farmers. These results suggest that slaveholders could extract rents from the enslaved in a multitude of ways beyond agriculture production and calls for a broader theory of slavery as capital investment.
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| 31290. |
- Martins, Igor
(författare)
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Collateral Effect : Slavery and Wealth in the Cape Colony
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis reassesses the framework we have come to accept around the dynamics of slavery in a series of papers which, together, shed new light on the economics of coercion. Employing a range of newly digitized historical databases covering the economic life and genealogical history of the British Cape Colony through the 18th and 19th centuries, it explores the determinants of labor coercion in light of two significant institutional shocks: the Slave Trade Act 1807, when the transshipment of slaves became illegal, and the Slave Abolition Act 1833 when the possession of slaves was outlawed. Slaveholding households are analyzed from a longitudinal perspective, such that the interdependencies of slave ownership, agricultural output, and related capital are considered simultaneously. It concludes that scenarios with weak property rights to land and lack of organized means for the provision of credit rendered slaves a suitable financial instrument allowing slaveholders to exploit the enslaved as means to raise capital beyond the agricultural labor. It magnifies the importance of slavery in the colony and provides economic historians with another tool to further interpret the profitability and the efficiency of the slave system. Understanding the proprietary relationship between masters and slaves and, consequently, their exploitation beyond agricultural work is key to explaining the dynamics of slavery in its entirety.
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