Integrated Optimal Power Flow for Distribution Networks in Local and Urban Scales

This paper develops an integrated optimal power flow (OPF) tool for distribution networks in two spatial scales. In the local scale, the distribution network, the natural gas network, and the heat system are coordinated as a microgrid. In the urban scale, the impact of natural gas network is considered as constraints for the distribution network operation. The proposed approach incorporates unbalance three-phase electrical systems, natural gas systems, and combined cooling, heating, and power systems. The interactions among the above three energy systems are described by energy hub model combined with components capacity constraints. In order to efficiently accommodate the nonlinear constraint optimization problem, particle swarm optimization algorithm is employed to set the control variables in the OPF problem. Numerical studies indicate that by using the OPF method, the distribution network can be economically operated. Also, the tie-line power can be effectively managed.

Big Data Analysis in Social Networks : Extracting Food Preferences of Vegans from Twitter

Market research is often conducted through conventional methods such as surveys, focus groups and interviews. But the drawbacks of these methods are that they can be costly and timeconsuming. This study develops a new method, based on a combination of standard techniques like sentiment analysis and normalisation, to conduct market research in a manner that is free and quick. The method can be used in many application-areas, but this study focuses mainly on the veganism market to identify vegan food preferences in the form of a profile. Several food words are identified, along with their distribution between positive and negative sentiments in the profile. Surprisingly, non-vegan foods such as cheese, cake, milk, pizza and chicken dominate the profile, indicating that there is a significant market for vegan-suitable alternatives for such foods. Meanwhile, vegan-suitable foods such as coconut, potato, blueberries, kale and tofu also make strong appearances in the profile. Validation is performed by using the method on Volkswagen vehicle data to identify positive and negative sentiment across five car models. Some results were found to be consistent with sales figures and expert reviews, while others were inconsistent. The reliability of the method is therefore questionable, so the results should be used with caution.

Intervenção Social - Arte ou Ciência?: O Assistente Social como agente de mudança numa autarquia de interior.

O presente trabalho baseia-se na pesquisa documental e na análise crítico-reflexiva sobre o serviço social no Poder Local, a sua evolução, influências e implicações no trabalho desenvolvido no (pelo) Gabinete de Ação Social do Município de Pampilhosa da Serra. O serviço social assume, durante o Estado Novo, um papel de controle, com uma prática associada essencialmente ao Estado e a algumas entidades da sociedade civil, nomeadamente à Igreja Católica. Com a Era Democrática, assiste-se ao crescimento da intervenção do Estado e à descentralização da sua atuação para as Autarquias, assumindo-se o SAAL (1974) como um marco histórico. A intervenção ganha, assim, um caráter “territorial” crescendo as responsabilidades das autarquias, quer no âmbito das transferências de competências por parte do Poder Central, quer ao nível da dinamização de serviços de âmbito municipal e da criação de respostas sociais específicas. O PRS (1997) e a RLIS (2013), apresentam-se como exemplos dessa territorialização, reforçando as atribuições das Autarquias ao nível da ação social. O primeiro, implementado a nível nacional, visa a articulação de recursos e uma intervenção integrada. Tem como princípios, a promoção a participação da população e dos agentes locais quer na elaboração de diagnósticos sociais, quer na criação de respostas adequadas às necessidades. A segunda, em fase de implementação, visa a criação de uma metodologia de trabalho ao nível do atendimento e acompanhamento social. Destaca-se o papel das Autarquias e da Sociedade Civil, na efetivação de uma intervenção social de proximidade. A crescente desresponsabilização do Estado na intervenção social, em particular do Poder Central, motivada pela Crise Económica, provoca alterações nas políticas sociais. Surgem as políticas de inserção direcionadas para públicos específicos, tendencialmente contratualizadas e centradas no sujeito. Estas alterações tiveram, também, implicações na atuação do Município de Pampilhosa da Serra, onde o serviço social se desenvolveu a par da implementação dos programas de âmbito comunitário, nomeadamente do PDIAS e PLCP (1996) e do projecto-piloto do RMG (1997). Sistematizou-se com a implementação das Redes Sociais e operacionaliza-se no Gabinete de Ação Social, atuando em três dimensões: mediação, promoção e execução. Da análise e reflexão em torno da atuação do GAS, no qual inscrevemos a nossa intervenção profissional, consideramos que esta se desenvolve numa relação sociopolítica e operacional, assumindo a Autarquia um papel ativo ao criar e/ou reforçar medidas de apoio socioeducativo e económico, de forma a garantir o bem-estar social e a qualidade de vida dos cidadãos Pampilhosenses. O município assume-se como o patamar de atuação de proximidade por excelência, onde o local se perspetiva como o espaço onde a intervenção social se operacionaliza, enquanto que o Poder Local, em conjunto com a sociedade Civil, assumem o poder de co construir a mudança social. / This work is based on documentary research and critical and reflective analysis of the social service in Local Government, its evolution, influences and implications on the work of the (at) Social Action Office of the municipality of Pampilhosa da Serra. The social service assumes, during the Estado Novo, a paper control, primarily associated with a practice the state and some civil society organizations, including the Catholic Church. With the Democratic Era, we are witnessing the growth of state intervention and the decentralization of its activities to the local authorities, assuming the SAAL (1974) as a historical landmark. Intervention win, so a character "territorial" growing responsibilities of local authorities, or within the transfer of responsibilities from the Central Power, both in terms of promotion of municipal services and the creation of specific social responses. The PRS (1997) and the RLIS (2013), are presented as examples of territorial, strengthening the powers of local authorities to the level of social action. The first, implemented nationally, aimed at articulating features and an integrated intervention. Its principles, promoting the participation of the population and local actors when developing social diagnosis, whether the creation of appropriate responses to the needs. The second, under implementation, aims to create a working methodology in terms of care and social support. It highlights the role of local authorities and civil society in the execution of a social intervention proximity. The growing irresponsibility of the state in social intervention, in particular the Central Power, motivated by the economic crisis, causes changes in social policies. Arise inclusion policies targeting specific audiences tend contracted and centered on the subject. These changes have also implications for the work of the municipality of Pampilhosa da Serra, where the social work developed together with the implementation of Community-wide programs, including the PDIAS and PLCP (1996) and the pilot project of RMG (1997). Systematized with the implementation of Social Networks and made operational in the Social Action Office, working in three dimensions: mediation, promotion and implementation. Analysis and reflection around the GAS operation, in which we inscribe our professional intervention, we believe that this is developed in a socio-political and operational relationship, assuming the Municipality an active role to create and / or strengthen measures of socio-educational and economic support, to ensure the welfare and quality of life of citizens Pampilhosenses. The municipality is assumed as the proximity actuation level par excellence where the location is perspective as the space where social intervention made operational, while the Local Government, together with civil society, assume the co power build social change.

Nature-based solutions to climate change mitigation and adaptation in urban areas: perspectives on indicators, knowledge gaps, barriers, and opportunities for action

Nature-based solutions promoting green and blue urban areas have significant potential to decrease the vulnerability and enhance the resilience of cities in light of climatic change. They can thereby help to mitigate climate change-induced impacts and serve as proactive adaptation options for municipalities. We explore the various contexts in which nature-based solutions are relevant for climate mitigation and adaptation in urban areas, identify indicators for assessing the effectiveness of nature-based solutions and related knowledge gaps. In addition, we explore existing barriers and potential opportunities for increasing the scale and effectiveness of nature-based solution implementation. The results were derived from an inter- and transdisciplinary workshop with experts from research, municipalities, policy, and society. As an outcome of the workshop discussions and building on existing evidence, we highlight three main needs for future science and policy agendas when dealing with nature-based solutions: (i) produce stronger evidence on nature-based solutions for climate change adaptation and mitigation and raise awareness by increasing implementation; (ii) adapt for governance challenges in implementing nature-based solutions by using reflexive approaches, which implies bringing together new networks of society, nature-based solution ambassadors, and practitioners; (iii) consider socio-environmental justice and social cohesion when implementing nature-based solutions by using integrated governance approaches that take into account an integrative and transdisciplinary participation of diverse actors. Taking these needs into account, nature-based solutions can serve as climate mitigation and adaptation tools that produce additional cobenefits for societal well-being, thereby serving as strong investment options for sustainable urban planning.

Adapting the social-ecological system framework for urban stormwater management: the case of green infrastructure adoption

Stormwater management has long been a critical societal and environmental challenge for communities. An increasing number of municipalities are turning to novel approaches such as green infrastructure to develop more sustainable stormwater management systems. However, there is a need to better understand the technological decision-making processes that lead to specific outcomes within urban stormwater governance systems. We used the social-ecological system (SES) framework to build a classification system for identifying significant variables that influence urban stormwater governance decisions related to green infrastructure adoption. To adapt the framework, we relied on findings from observations at national stormwater meetings in combination with a systematic literature review on influential factors related to green infrastructure adoption. We discuss our revisions to the framework that helped us understand the decision by municipal governments to adopt green infrastructure. Remaining research needs and challenges are discussed regarding the development of an urban stormwater SES framework as a classification tool for knowledge accumulation and synthesis.

Exploring social representations of adapting to climate change using topic modeling and Bayesian networks

When something unfamiliar emerges or when something familiar does something unexpected people need to make sense of what is emerging or going on in order to act. Social representations theory suggests how individuals and society make sense of the unfamiliar and hence how the resultant social representations (SRs) cognitively, emotionally, and actively orient people and enable communication. SRs are social constructions that emerge through individual and collective engagement with media and with everyday conversations among people. Recent developments in text analysis techniques, and in particular topic modeling, provide a potentially powerful analytical method to examine the structure and content of SRs using large samples of narrative or text. In this paper I describe the methods and results of applying topic modeling to 660 micronarratives collected from Australian academics / researchers, government employees, and members of the public in 2010-2011. The narrative fragments focused on adaptation to climate change (CC) and hence provide an example of Australian society making sense of an emerging and conflict ridden phenomena. The results of the topic modeling reflect elements of SRs of adaptation to CC that are consistent with findings in the literature as well as being reasonably robust predictors of classes of action in response to CC. Bayesian Network (BN) modeling was used to identify relationships among the topics (SR elements) and in particular to identify relationships among topics, sentiment, and action. Finally the resulting model and topic modeling results are used to highlight differences in the salience of SR elements among social groups. The approach of linking topic modeling and BN modeling offers a new and encouraging approach to analysis for ongoing research on SRs.

Revealing Cultural Ecosystem Services through Instagram Images : The Potential of Social Media Volunteered Geographic Information for Urban Green Infrastructure Planning and Governance

With the prevalence of smartphones, new ways of engaging citizens and stakeholders in urban planning and govern-ance are emerging. The technologies in smartphones allow citizens to act as sensors of their environment, producing and sharing rich spatial data useful for new types of collaborative governance set-ups. Data derived from Volunteered Geographic Information (VGI) can support accessible, transparent, democratic, inclusive, and locally-based governance situations of interest to planners, citizens, politicians, and scientists. However, there are still uncertainties about how to actually conduct this in practice. This study explores how social media VGI can be used to document spatial tendencies regarding citizens’ uses and perceptions of urban nature with relevance for urban green space governance. Via the hashtag #sharingcph, created by the City of Copenhagen in 2014, VGI data consisting of geo-referenced images were collected from Instagram, categorised according to their content and analysed according to their spatial distribution patterns. The results show specific spatial distributions of the images and main hotspots. Many possibilities and much potential of using VGI for generating, sharing, visualising and communicating knowledge about citizens’ spatial uses and preferences exist, but as a tool to support scientific and democratic interaction, VGI data is challenged by practical, technical and ethical concerns. More research is needed in order to better understand the usefulness and application of this rich data source to governance.

Automated Discovery of Social Networks in Online Learning Communities

As a way to gain greater insights into the operation of online communities, this dissertation applies automated text mining techniques to text-based communication to identify, describe and evaluate underlying social networks among online community members. The main thrust of the study is to automate the discovery of social ties that form between community members, using only the digital footprints left behind in their online forum postings. Currently, one of the most common but time consuming methods for discovering social ties between people is to ask questions about their perceived social ties. However, such a survey is difficult to collect due to the high investment in time associated with data collection and the sensitive nature of the types of questions that may be asked. To overcome these limitations, the dissertation presents a new, content-based method for automated discovery of social networks from threaded discussions, referred to as ‘name network’. As a case study, the proposed automated method is evaluated in the context of online learning communities. The results suggest that the proposed ‘name network’ method for collecting social network data is a viable alternative to costly and time-consuming collection of users’ data using surveys. The study also demonstrates how social networks produced by the ‘name network’ method can be used to study online classes and to look for evidence of collaborative learning in online learning communities. For example, educators can use name networks as a real time diagnostic tool to identify students who might need additional help or students who may provide such help to others. Future research will evaluate the usefulness of the ‘name network’ method in other types of online communities.

Joint Optimization for Social Content Delivery in Wireless Networks

Over the last decade, success of social networks has significantly reshaped how people consume information. Recommendation of contents based on user profiles is well-received. However, as users become dominantly mobile, little is done to consider the impacts of the wireless environment, especially the capacity constraints and changing channel. In this dissertation, we investigate a centralized wireless content delivery system, aiming to optimize overall user experience given the capacity constraints of the wireless networks, by deciding what contents to deliver, when and how. We propose a scheduling framework that incorporates content-based reward and deliverability. Our approach utilizes the broadcast nature of wireless communication and social nature of content, by multicasting and precaching. Results indicate this novel joint optimization approach outperforms existing layered systems that separate recommendation and delivery, especially when the wireless network is operating at maximum capacity. Utilizing limited number of transmission modes, we significantly reduce the complexity of the optimization. We also introduce the design of a hybrid system to handle transmissions for both system recommended contents ('push') and active user requests ('pull'). Further, we extend the joint optimization framework to the wireless infrastructure with multiple base stations. The problem becomes much harder in that there are many more system configurations, including but not limited to power allocation and how resources are shared among the base stations ('out-of-band' in which base stations transmit with dedicated spectrum resources, thus no interference; and 'in-band' in which they share the spectrum and need to mitigate interference). We propose a scalable two-phase scheduling framework: 1) each base station obtains delivery decisions and resource allocation individually; 2) the system consolidates the decisions and allocations, reducing redundant transmissions. Additionally, if the social network applications could provide the predictions of how the social contents disseminate, the wireless networks could schedule the transmissions accordingly and significantly improve the dissemination performance by reducing the delivery delay. We propose a novel method utilizing: 1) hybrid systems to handle active disseminating requests; and 2) predictions of dissemination dynamics from the social network applications. This method could mitigate the performance degradation for content dissemination due to wireless delivery delay. Results indicate that our proposed system design is both efficient and easy to implement.

NETCODE: an XOR-based warning dissemination scheme for vehicular wireless networks

The next generation of vehicles will be equipped with automated Accident Warning Systems (AWSs) capable of warning neighbouring vehicles about hazards that might lead to accidents. The key enabling technology for these systems is the Vehicular Ad-hoc Networks (VANET) but the dynamics of such networks make the crucial timely delivery of warning messages challenging. While most previously attempted implementations have used broadcast-based data dissemination schemes, these do not cope well as data traffic load or network density increases. This problem of sending warning messages in a timely manner is addressed by employing a network coding technique in this thesis. The proposed NETwork COded DissEmination (NETCODE) is a VANET-based AWS responsible for generating and sending warnings to the vehicles on the road. NETCODE offers an XOR-based data dissemination scheme that sends multiple warning in a single transmission and therefore, reduces the total number of transmissions required to send the same number of warnings that broadcast schemes send. Hence, it reduces contention and collisions in the network improving the delivery time of the warnings. The first part of this research (Chapters 3 and 4) asserts that in order to build a warning system, it is needful to ascertain the system requirements, information to be exchanged, and protocols best suited for communication between vehicles. Therefore, a study of these factors along with a review of existing proposals identifying their strength and weakness is carried out. Then an analysis of existing broadcast-based warning is conducted which concludes that although this is the most straightforward scheme, loading can result an effective collapse, resulting in unacceptably long transmission delays. The second part of this research (Chapter 5) proposes the NETCODE design, including the main contribution of this thesis, a pair of encoding and decoding algorithms that makes the use of an XOR-based technique to reduce transmission overheads and thus allows warnings to get delivered in time. The final part of this research (Chapters 6--8) evaluates the performance of the proposed scheme as to how it reduces the number of transmissions in the network in response to growing data traffic load and network density and investigates its capacity to detect potential accidents. The evaluations use a custom-built simulator to model real-world scenarios such as city areas, junctions, roundabouts, motorways and so on. The study shows that the reduction in the number of transmissions helps reduce competition in the network significantly and this allows vehicles to deliver warning messages more rapidly to their neighbours. It also examines the relative performance of NETCODE when handling both sudden event-driven and longer-term periodic messages in diverse scenarios under stress caused by increasing numbers of vehicles and transmissions per vehicle. This work confirms the thesis' primary contention that XOR-based network coding provides a potential solution on which a more efficient AWS data dissemination scheme can be built.

Russian social networks on the web: cohesion and coherence in Vkontakte

In this thesis connections between messages on the public wall of the Russian social network Vkontakte are analysed and classified. A total of 1818 messages from three different Vkontakte groups were collected and analysed according to a new framework based on Halliday and Hasan’s (1976) research into cohesion and Simmons’s (1981) adaptation of their classification for Russian. The two categories of textuality, cohesion and coherence, describe the linguistic connections between messages. The main aim was to find out how far the traditional categories of cohesion are applicable to an online social network including written text as well as multimedia-files. In addition to linguistic cohesion the pragmatic and topic coherence between Vkontakte messages was also analysed. The analysis of pragmatic coherence classifies the messages with acts according to their pragmatic function in relation to surrounding messages. Topic coherence analyses the content of the messages, describes where a topic begins, changes or is abandoned. Linguistic cohesion, topic coherence and pragmatic coherence enable three different types of connections between messages and these together form a coherent communication on the message wall. The cohesion devices identified by Halliday and Hasan and Simmons were found to occur in these texts, but additional devices were also identified: these are multimodal, graphical and grammatical cohesion.

ADVERTISEMENT ALLOCATION AND TRUST MECHANISMS DESIGN IN SOCIAL NETWORKS

Social network sites (SNS), such as Facebook, Google+ and Twitter, have attracted hundreds of millions of users daily since their appearance. Within SNS, users connect to each other, express their identity, disseminate information and form cooperation by interacting with their connected peers. The increasing popularity and ubiquity of SNS usage and the invaluable user behaviors and connections give birth to many applications and business models. We look into several important problems within the social network ecosystem. The first one is the SNS advertisement allocation problem. The other two are related to trust mechanisms design in social network setting, including local trust inference and global trust evaluation. In SNS advertising, we study the problem of advertisement allocation from the ad platform's angle, and discuss its differences with the advertising model in the search engine setting. By leveraging the connection between social networks and hyperbolic geometry, we propose to solve the problem via approximation using hyperbolic embedding and convex optimization. A hyperbolic embedding method, \hcm, is designed for the SNS ad allocation problem, and several components are introduced to realize the optimization formulation. We show the advantages of our new approach in solving the problem compared to the baseline integer programming (IP) formulation. In studying the problem of trust mechanisms in social networks, we consider the existence of distrust (i.e. negative trust) relationships, and differentiate between the concept of local trust and global trust in social network setting. In the problem of local trust inference, we propose a 2-D trust model. Based on the model, we develop a semiring-based trust inference framework. In global trust evaluation, we consider a general setting with conflicting opinions, and propose a consensus-based approach to solve the complex problem in signed trust networks.

Integration of Social Concerns in Collaborative Logistics and Transportation Networks

Part 21: Mobility and Logistics