5,741 research outputs found

    Measuring the Health and Development of School-age Zimbabwean Children

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    Health, growth and development during mid-childhood (from 5 to 14 years) are poorly characterised, and this period has been termed the ‘missing middle’. This thesis describes the piloting and application of the School-Age Health, Activity, Resilience, Anthropometry and Neurocognitive (SAHARAN) toolbox to measure growth, cognitive and physical function amongst the SHINE cohort in rural Zimbabwe. The SHINE cluster-randomised trial tested the effects of a household WASH intervention and/or infant and young child feeding (IYCF) on child stunting and anaemia at age 18 months in rural Zimbabwe. SHINE showed that IYCF modestly increased linear growth and reduced stunting by age 18 months, while WASH had no effects. The SAHARAN toolbox was used to measure 1000 HIV-unexposed children (250 in each intervention arm), and 275 HIV-exposed children within the SHINE cohort to evaluate long-term outcomes. Children were re-enrolled at age seven years to evaluate growth, body composition, cognitive and physical function. Four main findings are presented from the SAHARAN toolbox measurements of this cohort. Firstly, child sex, growth and contemporary environmental conditions are associated with school-age physical and cognitive function at seven years. Secondly, early-life growth and baseline environmental conditions suggest the impact of early-life trajectories on multiple aspects of school-age growth, physical and cognitive function. Thirdly, the long-term impact of HIV-exposure in pregnancy is explored, which indicate reduced cognitive function, cardiovascular fitness and head circumference by age 7 years. Finally, associations with the SHINE trial early life interventions are explored, demonstrating that the SHINE early-life nutrition intervention has minimal impact by 7 years of age, except marginally stronger handgrip strength. The public health implications advocate that child interventions need to be earlier (including antenatal), broader (incorporating nurturing care), deeper (providing transformational WASH) and longer (supporting throughout childhood), as well as targeting particularly vulnerable groups such as children born HIV-free

    A Trust Management Framework for Vehicular Ad Hoc Networks

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    The inception of Vehicular Ad Hoc Networks (VANETs) provides an opportunity for road users and public infrastructure to share information that improves the operation of roads and the driver experience. However, such systems can be vulnerable to malicious external entities and legitimate users. Trust management is used to address attacks from legitimate users in accordance with a user’s trust score. Trust models evaluate messages to assign rewards or punishments. This can be used to influence a driver’s future behaviour or, in extremis, block the driver. With receiver-side schemes, various methods are used to evaluate trust including, reputation computation, neighbour recommendations, and storing historical information. However, they incur overhead and add a delay when deciding whether to accept or reject messages. In this thesis, we propose a novel Tamper-Proof Device (TPD) based trust framework for managing trust of multiple drivers at the sender side vehicle that updates trust, stores, and protects information from malicious tampering. The TPD also regulates, rewards, and punishes each specific driver, as required. Furthermore, the trust score determines the classes of message that a driver can access. Dissemination of feedback is only required when there is an attack (conflicting information). A Road-Side Unit (RSU) rules on a dispute, using either the sum of products of trust and feedback or official vehicle data if available. These “untrue attacks” are resolved by an RSU using collaboration, and then providing a fixed amount of reward and punishment, as appropriate. Repeated attacks are addressed by incremental punishments and potentially driver access-blocking when conditions are met. The lack of sophistication in this fixed RSU assessment scheme is then addressed by a novel fuzzy logic-based RSU approach. This determines a fairer level of reward and punishment based on the severity of incident, driver past behaviour, and RSU confidence. The fuzzy RSU controller assesses judgements in such a way as to encourage drivers to improve their behaviour. Although any driver can lie in any situation, we believe that trustworthy drivers are more likely to remain so, and vice versa. We capture this behaviour in a Markov chain model for the sender and reporter driver behaviours where a driver’s truthfulness is influenced by their trust score and trust state. For each trust state, the driver’s likelihood of lying or honesty is set by a probability distribution which is different for each state. This framework is analysed in Veins using various classes of vehicles under different traffic conditions. Results confirm that the framework operates effectively in the presence of untrue and inconsistent attacks. The correct functioning is confirmed with the system appropriately classifying incidents when clarifier vehicles send truthful feedback. The framework is also evaluated against a centralized reputation scheme and the results demonstrate that it outperforms the reputation approach in terms of reduced communication overhead and shorter response time. Next, we perform a set of experiments to evaluate the performance of the fuzzy assessment in Veins. The fuzzy and fixed RSU assessment schemes are compared, and the results show that the fuzzy scheme provides better overall driver behaviour. The Markov chain driver behaviour model is also examined when changing the initial trust score of all drivers

    Proceedings of the 10th International congress on architectural technology (ICAT 2024): architectural technology transformation.

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    The profession of architectural technology is influential in the transformation of the built environment regionally, nationally, and internationally. The congress provides a platform for industry, educators, researchers, and the next generation of built environment students and professionals to showcase where their influence is transforming the built environment through novel ideas, businesses, leadership, innovation, digital transformation, research and development, and sustainable forward-thinking technological and construction assembly design

    Climate Change and Critical Agrarian Studies

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    Climate change is perhaps the greatest threat to humanity today and plays out as a cruel engine of myriad forms of injustice, violence and destruction. The effects of climate change from human-made emissions of greenhouse gases are devastating and accelerating; yet are uncertain and uneven both in terms of geography and socio-economic impacts. Emerging from the dynamics of capitalism since the industrial revolution — as well as industrialisation under state-led socialism — the consequences of climate change are especially profound for the countryside and its inhabitants. The book interrogates the narratives and strategies that frame climate change and examines the institutionalised responses in agrarian settings, highlighting what exclusions and inclusions result. It explores how different people — in relation to class and other co-constituted axes of social difference such as gender, race, ethnicity, age and occupation — are affected by climate change, as well as the climate adaptation and mitigation responses being implemented in rural areas. The book in turn explores how climate change – and the responses to it - affect processes of social differentiation, trajectories of accumulation and in turn agrarian politics. Finally, the book examines what strategies are required to confront climate change, and the underlying political-economic dynamics that cause it, reflecting on what this means for agrarian struggles across the world. The 26 chapters in this volume explore how the relationship between capitalism and climate change plays out in the rural world and, in particular, the way agrarian struggles connect with the huge challenge of climate change. Through a huge variety of case studies alongside more conceptual chapters, the book makes the often-missing connection between climate change and critical agrarian studies. The book argues that making the connection between climate and agrarian justice is crucial

    Computational and experimental studies on the reaction mechanism of bio-oil components with additives for increased stability and fuel quality

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    As one of the world’s largest palm oil producers, Malaysia encountered a major disposal problem as vast amount of oil palm biomass wastes are produced. To overcome this problem, these biomass wastes can be liquefied into biofuel with fast pyrolysis technology. However, further upgradation of fast pyrolysis bio-oil via direct solvent addition was required to overcome it’s undesirable attributes. In addition, the high production cost of biofuels often hinders its commercialisation. Thus, the designed solvent-oil blend needs to achieve both fuel functionality and economic targets to be competitive with the conventional diesel fuel. In this thesis, a multi-stage computer-aided molecular design (CAMD) framework was employed for bio-oil solvent design. In the design problem, molecular signature descriptors were applied to accommodate different classes of property prediction models. However, the complexity of the CAMD problem increases as the height of signature increases due to the combinatorial nature of higher order signature. Thus, a consistency rule was developed reduce the size of the CAMD problem. The CAMD problem was then further extended to address the economic aspects via fuzzy multi-objective optimisation approach. Next, a rough-set based machine learning (RSML) model has been proposed to correlate the feedstock characterisation and pyrolysis condition with the pyrolysis bio-oil properties by generating decision rules. The generated decision rules were analysed from a scientific standpoint to identify the underlying patterns, while ensuring the rules were logical. The decision rules generated can be used to select optimal feedstock composition and pyrolysis condition to produce pyrolysis bio-oil of targeted fuel properties. Next, the results obtained from the computational approaches were verified through experimental study. The generated pyrolysis bio-oils were blended with the identified solvents at various mixing ratio. In addition, emulsification of the solvent-oil blend in diesel was also conducted with the help of surfactants. Lastly, potential extensions and prospective work for this study have been discuss in the later part of this thesis. To conclude, this thesis presented the combination of computational and experimental approaches in upgrading the fuel properties of pyrolysis bio-oil. As a result, high quality biofuel can be generated as a cleaner burning replacement for conventional diesel fuel

    Spectrum auctions: designing markets to benefit the public, industry and the economy

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    Access to the radio spectrum is vital for modern digital communication. It is an essential component for smartphone capabilities, the Cloud, the Internet of Things, autonomous vehicles, and multiple other new technologies. Governments use spectrum auctions to decide which companies should use what parts of the radio spectrum. Successful auctions can fuel rapid innovation in products and services, unlock substantial economic benefits, build comparative advantage across all regions, and create billions of dollars of government revenues. Poor auction strategies can leave bandwidth unsold and delay innovation, sell national assets to firms too cheaply, or create uncompetitive markets with high mobile prices and patchy coverage that stifles economic growth. Corporate bidders regularly complain that auctions raise their costs, while government critics argue that insufficient revenues are raised. The cross-national record shows many examples of both highly successful auctions and miserable failures. Drawing on experience from the UK and other countries, senior regulator Geoffrey Myers explains how to optimise the regulatory design of auctions, from initial planning to final implementation. Spectrum Auctions offers unrivalled expertise for regulators and economists engaged in practical auction design or company executives planning bidding strategies. For applied economists, teachers, and advanced students this book provides unrivalled insights in market design and public management. Providing clear analytical frameworks, case studies of auctions, and stage-by-stage advice, it is essential reading for anyone interested in designing public-interested and successful spectrum auctions

    Constructing a profile for proactive career self-management in public higher education institutions in Ghana

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    Text in English with abstracts and keywords in English, isiXhosa, and isiZuluThe principal focus of this research study was to investigate the relationship among psychosocial career pre-occupation, social connectedness, and organisational commitment, and to determine whether an overall proactive career management profile can be constructed to inform career self-management practices in public higher education institutions (HEIs) in Ghana. Again, the research study intended to provide a background for testing hypotheses and theories as well as moderating the effect of socio-demographic characteristics (age, gender, marital status and job level) on the relationship between psychosocial career pre-occupations, social connectedness and organisational commitment. A cross-sectional quantitative approach was conducted on a purposively selected sample of senior staff comprising academic and administrative staff (n = 288), from a single public higher educational institution in Ghana. The measuring instruments include a career pre-occupations inventory workplace friendship scale and an organisational commitment scale. Descriptive statistics (mean, standard deviation, skewness and kurtosis), bi-variate correlation analysis (Pearson product moment correlation coefficient), and inferential and multivariate statistics (SEM analysis, moderated regression analysis, ANOVAs and independent sample t-test) were used for the study. Descriptive, bi-variate correlation and inferential statistics revealed that individual psychosocial career pre-occupations, social connectedness and organisational commitment can be used as elements within a proactive career self-management framework within the Ghanaian higher education institutions. The results of the moderated analysis showed that respondents’ gender and job level moderated employees’ level of psychosocial career pre-occupations in predicting organisational commitment. Furthermore, the test for significant mean differences revealed that gender, marital status and job level differed marginally in their psychosocial career pre-occupations, social connectedness and commitment to the organisation. Theoretically and empirically, the results advanced the career construction theory by empirically validating the core elements of career self-management. Practically, a recommendation was made to inform human resource (HR) managers and HR practitioners in public higher education institutions in Ghana and the consequences indicated in the study offer the opportunity to monitor and provide strategies and interventions for employees in their quest for career choices.Ugqaliselo oluphambili kolu phononongo lophando yayikukuphanda ubudlelwane phakathi komsebenzi wangaphambi kwekhondo ngokwesimo sengqondo nangokwezentlalo (psychosocial career pre-occupation), ukuziphatha, nokunxulumana kwezinto zokuziphatha nezentlalo (social connectedness), kunye nokuzibophelela kulungelelaniso /kucwangciso lombutho (organisational commitment), nokuqonda ukuba ingaba iprofayili yeendlela zokulawula ikhondo elisebenzayo elipheleleyo inokwakhelwa ukwazisa izenzo zekhondo lomsebenzi lokuzilawula kumaziko emfundo ephakamileyo karhulumente/oluntu (HEIs) eGhana. Kwakhona , uphononongo lophando lwaluzimisele ukunikezela ngomhlaba osisiseko wokuvavanya ingcinga ethathwa njengeyinyaniso engekaqinisekiswa (hypothesis) neethiyori kwakunye nokumodereyitha impembelelo yeempawu zedemografi yoluntu, i-socio-demographic characteristics (iminyaka, isini, imeko yomtshato,kunye nenqanaba lomsebenzi) kubudlelwane phakathi kwemisebenzi yangaphambi kwekhondo nemeko yezengqondo nabantu (psychosocial career pre-occupations), unxulumano lwabantu kunye nokuzibophelela kumbutho (organizational commitment). Inkqubo yophando ngokobungakanani enqamlezileyo ngokwamacandelo ahlukeneyo (cross sectional quantitative approach) yenziwe kwisampulu ekhethwe ngenjongo kujoliswe kubasebenzi abaphezulu/abadala ababandakanya izifundiswa nabasebenzi bezolawulo (n = 288), besuka kwiziko elinye loluntu lemfundo ephakamileyo eGhana. Izixhobo zokulinganisa zibandakanya uluhlu lwezinto kwisikali semisebenzi yangaphambi kwekhondo ubudlelwane kunye nokuzibophelela kumbutho kwindawo yokusebenzela. Iinkcukacha-manani ezichazayo (i-avareji, ukutenxa kumgangatho (standard deviation), ubugoso (skewness) kunye nomlinganiselo weenkcukacha-manani osetyenziselwa ukuchaza ukuhanjiswa kwedatha ephawulweyo malunga nentsingiselo (kurtosis), uhlalutyo lolungelelwaniso oluphindwe kabini kunye neenkcukacha-manani ezinokuthelelelekwa (i- Pearson product moment correlation coefficient), kunye neenkcukacha manani ezizintlobo-ntlobo ezininzi ezinokuthelekelelwa (uhlalutyo lwe-SEM, uhlalutyo oluhlehlayo olonganyelweyo/ olumodareyithiweyo, i-ANOVA kunye novavanyo oluzimeleyo lwe-t-test) zasetyenziswa kolu phando/phononongo. Inkcukacha-manani ezichazayo, ulungelelwaniso/unxulumaniso oluphindwe kabini kunye nezinokuthelekelelwa ezinentsingiselo zibonise ukuba imisebenzi yangaphambi kwekhondo,ngokwemeko yengqondo neyentlalo, unxulumano lwentlalo yoluntu kunye nokuzibophelela kumbutho kunokusetyenziswa njengezinto ezingaphakathi kwesakhelo solawulo esisebenzayo ngaphakathi kumaziko emfundo ephakamileyo yaseGhana.Iziphumo zohlalutyo olumodareyithiweyo zibonise ukuba isini sabaphenduli nenqanaba lomsebenzi samodareyitha inqanaba labasebenzi kwimisebenzi yangaphambi kwekhondo kwimeko yengqondo nezentlolontle ekuqikeleleni ukuzibophelela kumbutho. Ngaphaya koko, uvavanyo olubalulekileyo lweeyantlukwano lubonise ukuba isini, meko yomtshato kunye nenqanaba lomsebenzi lahlukile kancinci ngokwe-avareji kwimisebenzi yaphambi kwekhondo labo yengqondo nentlalontle, unxibelelwano lwentlalo kunye nokuzinikela embuthweni. Ngokwethiyori nangobungqina, iziphumo ziqhubele phambili ithiyori yolwakhiwo lwekhondo lomsebenzi ngokuqinisekisa ngobuchule izinto ezingundoqo zokuzilawula kwekhondo lomsebenzi.Ngokwenene, kwenziwa isindululo sokwazisa abaphathi bezabasebenzi neengcali ze-HR kumaziko emfundo ephakamileyo yoluntu eGhana kwaye iziphumo ezibonakaliswe kuphononongo zinika ithuba lokubeka esweni nokubonelela ngezicwangciso-qhinga nongenelelo ngoncedo kubaqeshwa kwiphulo labo lokukhetha amakhondo omsebenzi.Lesi sifundo socwaningo sasigxile kakhulu ekuphenyeni ngobudlelwano phakathi kokucabanga ngomkhakha womsebenzi komuntu, ukuxhumana nabantu, ukuzibophezela komuntu emsebenzini, kanye nokunquma ukuthi iphrofayili yokukwazi ukuzilawula ngokuzenzela ekukhetheni umkhakha womsebenzi kungahlelwa yini ngendlela yokuthi kudlale indima ekuzilawuleleni maqondana nomkhakha womsebenzi ezikhungweni zezemfundo ephakeme zomphakathi (ama-HEI) eGhana. Kanti futhi, isifundo socwaningo sihlose ukunikeza umlando maqondana nokuhlola imicabango kanye nemibono yezinjulalwazi kanjalo nokulinganisa umphumela wezici zokuhleleka kwabantu emphakathini (iminyaka yobudala, ubulili, isimo somshado kanye nezinga lomsebenzi) ebudlelwaneni phakathi kokucabanga ngomkhakha womsebenzi komuntu, ukuxhumana nabantu, kanye nokuzibophezela emsebenzini. Kwalandelwa indlela yokubheka isibalo samaqoqo abantu emphakathini ngokukhetha ngokuqaphela isampula labasebenzi abasezikhundleni eziphezulu elibandakanya abasebenza ngezemfundo kanye nezokuphatha (n = 288), esikhungweni sezemfundo ephakeme somphakathi esisodwa eGhana. Amathuluzi okukala afaka kuwo isilinganiso sobungane basemsebenzini ekukhetheni ezinhlobeni zemikhakha ecatshangwayo kanye nesilinganiso maqondana nokuzibophezela kwabantu emsebenzini. Kulolu cwaningo kwasetshenziswa izibalo ezichazayo (okujwayelekile, ukuphambuka okuvamile, ukungalingani kanye nobukhali), ukuhlaziywa kokuhlobana okukhona phakathi kwezinombolo ezimbili (isilinganiso sokuxhumana kwezinombolo ezimbili ngokukaPearson), kanye nezibalo eziveza izimbangela nezibalo ezahlukahlukene (ukuhlaziywa kwe-SEM, ukuhlaziywa kokubuyelamuva okulingene, ama-ANOVA kanye nesampula elizimele lokuhlola). Izibalo ezichazayo, eziveza ukuhlobana phakathi kwezinombolo ezimbili kanye nezibalo eziveza izimbangela ziveze ukuthi ukucabanga ngomkhakha womsebenzi komuntu ngamunye, ukuxhumana nabantu nokuzibophezela emsebenzini kungasetshenziswa njengezinto ezikhona ohlakeni lokukwazi ukuzilawula ngokuzenzela ekukhetheni umkhakha ezikhungweni zezemfundo ephakeme zaseGhana. Imiphumela yokuhlaziywa okulingene yakhombisa ukuthi ubulili bababambiqhaza kanye nezinga labo ngokwezikhundla zomsebenzi kuhambisana nezinga abasebenzi abacabanga ngalo nomkhakha womsebenzi ekuqageleni indlela abazozibophezela ngayo emsebenzini. Ngaphezu kwalokho, ukuhlolwa komehluko omkhulu ojwayelekile kwaveza ukuthi ubulili, isimo somshado kanye nezinga ngokwesikhundla somsebenzi kwahluka kakhulu nendlela abacabanga ngayo ngomkhakha womsebenzi, ukuxhumana nabantu nokuzibophezela emsebenzini. Ngokombono wenjulalwazi nocwaningo olufakazelwe, imiphumela ithuthukise umbono wenjulalwazi wokuhlela umkhakha womsebenzi okuqinisekiswe ngokocwaningo olufakazelwe izinto ezinqala zokuzilawulela umkhakha womsebenzi. Ekusebenzeni, kwenziwa izincomo zokufundisa abaphathi babasebenzi (ba-HR) kanye nabasebenza ngezabasebenzi (ngezakwa-HR) ezikhungweni zezemfundo ephakeme zomphakathi eGhana, kanti nemiphumela evezwe ocwaningweni inikeza ithuba lokuqapha nokuhlinzeka amasu kanye nokungenelela kwabasebenzi ekwenzeni kwabo izinqumo zomsebenzi.Business ManagementPh. D. (Business Management

    Special Delivery: Programming with Mailbox Types (Extended Version)

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    The asynchronous and unidirectional communication model supported by mailboxes is a key reason for the success of actor languages like Erlang and Elixir for implementing reliable and scalable distributed systems. While many actors may send messages to some actor, only the actor may (selectively) receive from its mailbox. Although actors eliminate many of the issues stemming from shared memory concurrency, they remain vulnerable to communication errors such as protocol violations and deadlocks. Mailbox types are a novel behavioural type system for mailboxes first introduced for a process calculus by de'Liguoro and Padovani in 2018, which capture the contents of a mailbox as a commutative regular expression. Due to aliasing and nested evaluation contexts, moving from a process calculus to a programming language is challenging. This paper presents Pat, the first programming language design incorporating mailbox types, and describes an algorithmic type system. We make essential use of quasi-linear typing to tame some of the complexity introduced by aliasing. Our algorithmic type system is necessarily co-contextual, achieved through a novel use of backwards bidirectional typing, and we prove it sound and complete with respect to our declarative type system. We implement a prototype type checker, and use it to demonstrate the expressiveness of Pat on a factory automation case study and a series of examples from the Savina actor benchmark suite.Comment: Extended version of paper accepted to ICFP'2

    Exploiting Process Algebras and BPM Techniques for Guaranteeing Success of Distributed Activities

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    The communications and collaborations among activities, pro- cesses, or systems, in general, are the base of complex sys- tems defined as distributed systems. Given the increasing complexity of their structure, interactions, and functionali- ties, many research areas are interested in providing mod- elling techniques and verification capabilities to guarantee their correctness and satisfaction of properties. In particular, the formal methods community provides robust verification techniques to prove system properties. However, most ap- proaches rely on manually designed formal models, making the analysis process challenging because it requires an expert in the field. On the other hand, the BPM community pro- vides a widely used graphical notation (i.e., BPMN) to design internal behaviour and interactions of complex distributed systems that can be enhanced with additional features (e.g., privacy technologies). Furthermore, BPM uses process min- ing techniques to automatically discover these models from events observation. However, verifying properties and ex- pected behaviour, especially in collaborations, still needs a solid methodology. This thesis aims at exploiting the features of the formal meth- ods and BPM communities to provide approaches that en- able formal verification over distributed systems. In this con- text, we propose two approaches. The modelling-based ap- proach starts from BPMN models and produces process al- gebra specifications to enable formal verification of system properties, including privacy-related ones. The process mining- based approach starts from logs observations to automati- xv cally generate process algebra specifications to enable veri- fication capabilities
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