On a regular basis, project managers concentrate their efforts on critical and near-critical activities. However, the concepts of total float and critical path lose their significance after applying resource-constrained scheduling (RCS) methodologies. RCS techniques solve the resource conflicts but create phantom float in the schedules (i.e., a float that does not exist). RCS techniques overlook the resources relationships between activities that compete for the same but unavailable resources. Therefore, each time an activity uses this apparent float (phantom float), there is a resource violation in the schedule. Due to the projects' size and complexity, schedulers use scheduling software such as Primavera P6 to fix the resource conflicts of a schedule. The software correctly determines the activities' earliest dates that satisfy the resource limitations, but they calculate total float based on a "Time Context" ignoring the presence of resource constraints. Thus, the results show incorrect total float values and a broken critical path. The lack of a continuous critical path makes impossible the anticipation of the impact of a delaying event in the project completion time. Several algorithms have been developed to address the shortcomings of RCS methods. These RCS related algorithms were developed with the aim of providing project managers a tool to correctly schedule and identify critical activities with respect to time and resource allocation and correctly calculate the total float of each activity under resource constraints. In this regard, the Resource-Constrained Critical Path Method (RCPM) is an algorithm that correctly calculates the floats of activities and identifies a continuous critical path in resource-constrained schedules. Regardless of the RCPM provides more reliable float values than traditional RCS-related algorithms, there are some shortcomings that must be addressed to enhance its capability. This study addresses the existing shortcomings of RCPM to make it more practical for real construction projects. / Doctor of Philosophy / One of the challenges of resource allocation is resource availability because oftentimes, the resource demand exceeds the supply. When resources are over-allocated, activities are delayed until resources become available. Due to the projects' size and complexity, schedulers use available software to solve the resource conflicts of a schedule. After testing Primavera P6 versions and MS Project v2016, both software create phantom float in a resource-constrained schedule. This is, the RCS calculations suggest that activities have float, but this float might not exist at all. Resource-Constrained Scheduling (RCS) techniques mitigate a resource supply-demand problem but fail to identify a project critical path. The methods do not consider the resource-activity dependencies that arise when activities are delayed due to resource limits. As a result, the critical path is broken, and all the activities must be considered as critical. To provide correct float values and a continuous critical path, the Resource-Constrained Critical Path (RCPM) was introduced by Kim and de la Garza in 2003. Regardless of the RCPM provides more reliable float values than traditional RCS-related algorithms, there are some shortcomings that must be addressed to enhance its capability. This study addresses the existing shortcomings of RCPM to make it more practical for real construction projects.

Patrick and Felicia are a couple who run a farm. Every day they harvest their crops and sell them at the local market. This is the family's everyday life and today's income goes to all the family'sexpenses such as food, water, and transport to the market. At the end of the day, the family's totalbudget results in plus or minus zero. The crop that was not sold must be thrown away because itrots during the night. If the family had a refrigerator, they would have been able to store the cropsand extend their life of it, which in turn gives them the opportunity to also sell the crops the nextday and earn more money. The crux of the family is that the cheapest refrigerator on the marketis far too expensive to buy and operate due to electricity costs. The cooler of MittiCool Clay is acooler made of clay that costs around 1000 SEK and does not need electricity. Instead, it uses thenatural laws of thermodynamics to cool the contents making it free to operate.This is an example of a scenario where a product can create value for a family living in a resourceconstrainedenvironment (RCE). The product can offer a possible way to be able to save moneyand eventually be able to afford schooling for their child, a savings capital for crises and healthcareThis thesis uses a human-centred design process to create a solution for this target group. Thechallenge for these particular people in this project is the low access to clean water.Through a need-finding process that resulted in 10 insights that served as a guide in the project.In three workshops and with a contoured idea generation process with residents and designteachers, a variety of ideas could be developed. The ideas were put together and became concepts.The concept was evaluated through an evaluation matrix based on the needs of the users, thetechnical possibility, and the potential financial sustainability. At the end of the evaluationprocess, one concept remained Life Cube. The concept is a franchise, product and a service thatenables residents to clean their grey cat through an off-grid "cube" to drinkable quality. Theconcept also provides an opportunity for a prospective cube owner to run his own business andoffer this service.Four billion people live at the bottom of the socio-economic pyramid and can be potentialcustomers. The feasibility study showed that there are very few products in this market today andthat the number of potential customers is large. Creating a so-called ‘frugal innovation’, combinedwith the fact that it is financially sustainable with very small funds, is complex. This requires thatthe innovator works locally with the user's specific needs and usually with local resources and thatthe local economic and physical infrastructure is considered.The conclusion is that one can use human-centred design to create products and services for peopleliving in a resource-constrained environment. The basis of the process is based on people's needs,economic situation, infrastructure, institutions, resource availability, which are essential factorsto consider for the solution desired by the user, technically viable and financially sustainable. Asecond conclusion is that the difficulties of product development towards this target group requireresources and knowledge that are not usually required in product development contexts towardsthe market that belonged to the top of the socio-economic pyramid, which can complicate theproduct development. / Patrick och Felicia är ett par som driver en odling. Varje dag skördar de sina grödor och säljer påden lokala marknaden. Det här är familjens vardag och dagens inkomst går åt till alla familjensutgifter som mat, vatten och transport till marknaden. I slutet av dagen så resulterar familjenstotalbudget i plus minus noll. Skörden som inte blev såld måste slängas för att den ruttnar ändåunder natten. Hade familjen haft ett kylskåp hade dom kunat förvara grödorna och förlängtlivstiden på den, som i sin tur ger dom möjligheten att även sälja grödorna dagen efter och tjänamer pengar. Kruxet för famlijen är att den billigaste kylen på marknaden är alldeles för dyr attköpa och driva på grund av elkostnaderna. Kylen av MittiCool Clay är en kyl gjord i lera somkostar runt 1000 SEK och istället använder termodynamikens naturlagar för att kyla innehållet,vilket gör att den inte kostar något att driva.Detta är ett exempel på ett scenario där en product kan skapa värde för en familj som lever i enresursbegränsad miljö (RBM). Produkten kan erbjuda en möjlig väg för att kunna spara pengaroch så småning om kunna ha råd med en skolgång till sitt barn, ett sparkapital för krissituationeroch sjukvård. Detta examensarbete använder en människocentrerad design process för attskapa en lösning mot denna målgrupp, alltså människor som lever i en resurs begränsad miljö.Utmaningen för just dessa personer i detta projekt är den låga tillgången till rent vatten.Genom en behovsidentifieringsprocess som resulterade i 10 stycken insikter som fungeradesom en guide i projektet. I tre workshops och med en konteurnelig idegenereringsprocess medlokala invånare och designlärare kunde en mängd ideer tas fram. Ideerna sammanfogades ochblev till koncept. Koncepten utvärderades genom en utvärderingsmatris som grundades påanvädnarnas behov, den tekniska möjligheten och den potentiellt finansiella hållbarheten. I slutetav utvärderingsprocessen återstod ett concept, Life Cube. Konceptet är en franchise, produkt ochen tjänst som möjligör för lokalbon att rena sitt gråvatten genom en off-grid “kub” till drickbarkvalité. Konceptet ger även möjlighet för en blivande kub-ägare att driva sin egen verksamhet ocherbjuda denna tjänst.Förstudien visade att det finns väldigt få produkter mot denna marknad idag och att antaletpotentiella kunder är stort. Fyra miljarder människor lever i botten av den socioekonomiskapyramiden och kan vara potentiella kunder. Att skapa en så kallat ‘frugal innovation’, ikombination med att den är finansiellt hållbar med väldigt små medel är komplext. Det kräver attinnovatören arbetar lokalt med användarens specifika behov och oftast med lokala resurser, samtatt den lokala ekonomiska och fysiska infrastrukturen tas i beaktning.Slutsattsen är att man kan använda människocentrerad design för att skapa produkter ochtjänster för människor som lever i en resursbegränsad miljö. Processens grund baseras påmänniskornas behov, ekonomsika situation, infrastruktur, institutioner, resurstillgängligheten,vilket är essensiella faktorer att ta hänsyn till för att lösningen ska vara önskvärd av användaren,teknisk möjlig och finansiellt hållbar. En andra slutsats är svårigheterna med att produktutvecklamot denna målgrupp kräver resurser och kunskap som vanligtvis inte krävs i produktutvecklingssammanhang mot marknaden som tillhör toppen av den socioekonomiska pyramiden, vilketkan försvåra utvecklingsarbetet.

This thesis was submitted to the faculty of Innovation, Design and Technology, IDT, at Mälardalen university in Västerås, Sweden as a partial fulfillment of the requirements to obtain the M.Sc. in computer science, specializing in embedded systems. The work presented was carried out in the months January to June in 2014 partially in Volvo Construction Equipment, Volvo CE, Eskilstuna, and partially at Mälardalen university in Västerås. Federated Resilient Embedded Systems Technology for AUTOSAR, FRESTA, is a collaborative project between Volvo and the Swedish Institute of Computer Science, SICS, that aims to make it possible to add third party applications to vehicle’s computer systems without compromising system security and robustness. The mechanism is developed by SICS for AUTOSAR, AUTomotive Open System ARchitecture, an open standardized automotive software architecture for vehicles. The following report documents the efforts to study and port the FRESTA mechanism to the Volvo CE platform, and develop a Java application to test the porting. The investigation will aspire to determine if it is feasible to introduce Java based third party applications to resource constrained embedded systems, without causing a deterioration in the predictability and security of the system. / Avhandlingen lades fram för fakulteten för innovation, design och teknik, IDT, vid Mälardalens högskola i Västerås som en del av kraven för att erhålla M.Sc. i datavetenskap med inriktning mot inbyggda system. Arbetet genomfördes under månaderna januari till juni 2014 delvis i Volvo Construction Equipment, Volvo CE, Eskilstuna, och delvis vid Mälardalens högskola i Västerås. Federated Resilient Embedded Systems Technology for AUTOSAR, FRESTA, är ett samarbetsprojekt mellan Volvo och Svenska Institutet för datavetenskap, SICS, som syftar till att göra det möjligt att lägga tredjepartsapplikationer till fordonets datorsystem utan att äventyra systemets säkerhet och robusthet. Mekanismen är utvecklat av SICS för AUTOSAR, Automotive Open System Architecture, en öppen standardiserad fordons programvaruarkitektur för fordon. Följande rapport dokumenterar arbetet med att studera Fresta mekanismen till Volvo CE-plattformen, och utveckla ett Java-program för att testa portning. Undersökningen kommer att sträva efter att avgöra om det är genomförbart att införa en Java-baserad tredje part för att resursbegränsa inbyggda system, utan att orsaka en försämring av förutsägbarhet och säkerhet i systemet.

The emergence of the Internet of Things (IoT) has increased the demand for networked, resource-constrained devices tremendously. Many of the devices used for IoT applications are designed to be resource-constrained, as they typically must be small, inexpensive, and powered by batteries. In this dissertation, we consider a number of challenges pertaining to these constraints: system support for energy efficiency; flash-based storage systems; programming, testing, and debugging; and safe and secure application execution. The contributions of this dissertation are made through five research papers addressing these challenges. Firstly, to enhance the system support for energy-efficient storage in resource-constrained devices, we present the design, implementation, and evaluation of the Coffee file system and the Antelope DBMS. Coffee provides a sequential write throughput that is over 92% of the attainable flash driver throughput, and has a constant memory footprint for open files. Antelope is the first full-fledged relational DBMS for sensor networks, and it provides two novel indexing algorithms to enable fast and energy-efficient database queries. Secondly, we contribute a framework that extends the functionality and increases the performance of sensornet checkpointing, a debugging and testing technique. Furthermore, we evaluate how different data compression algorithms can be used to decrease the energy consumption and data dissemination time when reprogramming sensor networks. Lastly, we present Velox, a virtual machine for IoT applications. Velox can enforce application-specific resource policies. Through its policy framework and its support for high-level programming languages, Velox helps to secure IoT applications. Our experiments show that Velox monitors applications' resource usage and enforces policies with an energy overhead below 3%. The experimental systems research conducted in this dissertation has had a substantial impact both in the academic community and the open-source software community. Several of the produced software systems and components are included in Contiki, one of the premier open-source operating systems for the IoT and sensor networks, and they are being used both in research projects and commercial products.

<p>Cyber physical systems are deployed in a wide range of applications from sensor nodes in a factory setting to drones in defense applications. This distributed setting of nodes or processes often needs to reach agreement on a set of values. Byzantine Agreement protocols address this issue of reaching an agreement in an environment where a malicious entity can take control over a set of nodes and deviates the system from its normal operation. However these protocols do not consider the energy consumption of the nodes. We explore Byzantine Agreement protocols from an energy efficient perspective providing both <i>energy resilience</i> where the actions of the Byzantine nodes can not adversely effect the energy consumption of non-malicious nodes as well as <i>fairness</i> in energy consumption of nodes over multiple rounds of agreement.</p>

Der Planungsprozess des Produktionsablaufes ist insbesondere in personalintensiven Bereichen durch einen hohen Komplexitätsgrad gekennzeichnet. Dies gilt nicht allein für die Domäne der Fertigung von Industriegütern, sondern ist überall dort charakteristisch, wo projektähnliche Aufgaben und Tätigkeiten im Kurzfristbereich hinsichtlich Ressourcenzuteilung determiniert werden müssen. Personal ist hierbei weitaus weniger homogen, als dies auf andere Ressourcentypen zutrifft. Daher gilt es der Heterogenität der Prozesse und Strukturen unter Beachtung individuell ausgeprägter Eigenschaften und Fähigkeiten des Personals einen quantitativ beschreibbaren und damit operationali-sierbaren Rahmen zu geben. Die Komplexität einer personalbezogenen, zielfunktionsorientierten Zuteilungsentscheidung kann im Kontext der Kapazitätsplanung damit signifikant reduziert werden.

Sensor devices and the emergent networks that they enable are capable of transmitting information between data sources and a permanent data sink. Since these devices have low-power and intermittent connectivity, latency of the data may be tolerated in an effort to save energy for certain classes of data. The BUBBLE routing algorithm developed by Hui et al. in 2008 provides consistent routing by employing a model which computes individual nodes popularity from sets of nodes and then uses these popularity values for forwarding decisions. This thesis considers enhancements to BUBBLE based on the hypothesis that nodes do form groups and certain centrality values of nodes within these groups can be used to improve routing decisions further. Built on this insight, there are two algorithms proposed in this thesis. First is the Community-Based- Forwarding (CBF), which uses pairwise group interactions and pairwise node-to-group interactions as a measure of popularity for routing messages. By having a different measure of popularity than BUBBLE, as an additional factor in determining message forwarding, CBF is a more conservative routing scheme than BUBBLE. Thus, it provides consistently superior message transmission and delivery performance at an acceptable delay cost in resource constrained environments. To overcome this drawback, the concept of unique interaction pattern within groups of nodes is introduced in CBF and it is further renewed into an enhanced algorithm known as Hybrid-Community-Based- Forwarding (HCBF). Utilizing this factor will channel messages along the entire path with consideration for higher probability of contact with the destination group and the destination node. Overall, the major contribution of this thesis is to design and evaluate an enhanced social based routing algorithm for resource-constrained Pocket Switched Networks (PSNs), which will optimize energy consumption related to data transfer. It will do so by explicitly considering features of communities in order to reduce packet loss while maintaining high delivery ratio and reduced delay.

No description available.

This study forms part of three broader projects1 where school-based vegetable gardens have been implemented in nine primary schools in resourced-constrained communities in the Nelson Mandela Metropole, South Africa. The purpose of the current study was to explore teacher perceptions of the role of school principals in the success and sustainability of these school-based vegetable gardens. For the purpose of my research, I followed a qualitative methodological approach, and relied on interpretivism as epistemological paradigm. I utilised a multiple case study research design, applying Participatory Reflection and Action (PRA) principles. I purposefully selected 36 teachers from the nine schools involved in the broader project to participate in this study. For data generation and documentation, I relied on a PRA-based workshop, semi-structured individual interviews, observation, field notes, a research journal and audio-visual techniques. I completed inductive thematic analysis. Three main themes and related sub-themes emerged. The first theme highlights the value that teacher participants attach to school principals being informed and involved in vegetable gardens, by sharing the dream and being passionate, being informed of the garden team’s needs and challenges, and being actively involved. The second theme emphasises the importance of a principal providing support by motivating and encouraging teachers and learners to be involved, providing resources and fundraising opportunities, and networking with stakeholders. Finally, the last theme entails factors that may have a negative impact on the success of school-based vegetable gardens in terms of limited interest and involvement by the principal, and not recognising the value of the teachers or the school garden. The findings of the current study indicate that the majority of the teacher participants acknowledged the positive roles that their principals fulfilled, which they then linked to the success and sustainability of their school-based vegetable gardens. Teacher participants indicated that effective leadership can be demonstrated when school principals lead by example, provide the necessary resources, are well informed and knowledgeable about school gardens, and show support to those involved. / Dissertation (MEd)--University of Pretoria, 2019. / Educational Psychology / MEd / Unrestricted

This study forms part of three broader research projects that focus on investigating ways in which teachers can promote resilience in resource-constrained contexts by means of implementing school health initiatives, such as school-based vegetable gardens. Following on a need identified within the broader research projects, the purpose of this study was to explore and describe teachers’ perceptions of involving different groups of role-players in school-based vegetable gardens in resource-constrained contexts in an attempt to understand how different role-players may contribute to successful gardens. For this purpose, I focused on the experiences of 36 primary school teachers from nine schools in the Eastern Cape province who have been involved in school-based vegetable gardens in recent years. I was guided by Ozer’s (2007) model of potential effects of school gardens as theoretical framework, utilised interpretivism as meta-theory and followed a qualitative methodological approach. I selected a case study research design, applying Participatory Reflection and Action (PRA) principles. Data were generated and documented by means of a PRA-based workshop, five semi-structured interviews and observation-as-contextof- interaction, supported by visual and audio documentation techniques, field notes and a reflective journal. Following inductive thematic analysis, I identified four themes and related sub-themes. The themes relate to role-players often involved in school-based vegetable gardens as well as their respective responsibilities; benefits associated with involving the various role-players; factors that may support the successful establishment and maintenance of school-based vegetable gardens, and challenges experienced when involving the different role-players. The findings of this study indicate that teachers experienced the role that different groups of people may fulfil positively despite some challenges associated with such involvement. More specifically, role-players in school-based vegetable gardens can significantly contribute to the success of such gardens by supporting teachers in developing innovative solutions to the challenges they face. Teachers and learners were found to be the primary role-players, supported by dedicated school principals and in many cases, one or two gardeners that may also be community members. Lastly, a dedicated garden coordinator (such as a teacher) and support by the national Department of Basic Education were found to be important. / Dissertation (MEd)--University of Pretoria, 2019. / Educational Psychology / MEd / Unrestricted