439 research outputs found

    Shared-memory Graph Truss Decomposition

    Full text link
    We present PKT, a new shared-memory parallel algorithm and OpenMP implementation for the truss decomposition of large sparse graphs. A k-truss is a dense subgraph definition that can be considered a relaxation of a clique. Truss decomposition refers to a partitioning of all the edges in the graph based on their k-truss membership. The truss decomposition of a graph has many applications. We show that our new approach PKT consistently outperforms other truss decomposition approaches for a collection of large sparse graphs and on a 24-core shared-memory server. PKT is based on a recently proposed algorithm for k-core decomposition.Comment: 10 pages, conference submissio

    From school to work : Muslim youths\u27 education and employment strategies in a community in Uttar Pradesh, India

    Get PDF
    India\u27s Muslim community, which accounts for 14.4 percent of India’s vast population and is thus the largest of all religious minorities, has been the subject of considerable development discourse as Muslims have the lowest level of educational attainment and standard of living among socio-religious groups in the country. This study addresses the meaning of education and career opportunities for Muslim youths in relation to their educational credentials and social position in the hierarchy of Muslim class and caste groups, with particular reference to a community in Uttar Pradesh. The author contends that the career opportunities, possibilities, and strategies of Muslim youths in Indian society depend on multiple factors: social hierarchy, opportunities to utilize economic resources, social networks, cultural capital, and the wider structural disparities within which the Muslims are situated and wherein they question the value of higher education in gaining them admission to socially recognized and established employment sectors

    Somatic Embryogenesis in Musa Spp.

    Get PDF
    Embryogenesis competent material (scalp) was initiated from shoot tip of Musa spp. cultivar Mas (AA), Berangan (AAA), Intan (AAA), Raja (AAB) and Tanduk (AAB). Somatic embryogenesis were investigated from four explant sources viz., scalps, male flower primordia, in vitro corm slices and immature ovules of Musa acuminata cv. Mas. Scalp formation was optimal on Murashige and Skoog (MS) medium with modified vitamins supplemented with 100 /lM BAP and 1.0 /lM IAA. Among the cultivars investigated, cv. Mas was the most responsive for scalp formation whereby 40% of the shoot tips formed scalps by the 7th month of culture. Cultivar Mas was also the most responsive for meristematic globule formation from scalps attaining 100% meristematic globule formation by week 7 of culture of scalps in Z medium. Cells with embryogenic potential were released from the meristematic globules of cv . Mas after 10 to 12 months of culture of the meristematic globules in Z medium . The embryogenic cell suspension was transferred to liquid S medium and formed globular embryos after 3 to 4 months in culture. Matured globular embryos upon transfer to liquid S regeneration medium supplemented with 0, 1.0, 5.0, 10, 20, 40 and 80 /lM BAP germinated to form roots but without shoots

    Capacity development of tribal forest dwellers through Participatory Forest Management in Bangladesh

    Get PDF
    This thesis examines the Participatory Forest Management (PFM) approach in the micro-scale context of the Madhupur Sal forest in Bangladesh. In Bangladesh, PFM has been the main policy instrument for managing natural forest areas in the last two decades. The present national forest policy in Bangladesh emphasizes the importance of the participation of different actors, especially forest dwellers, in forest management programs. The overall aim of PFM is to capacitate and to improve the livelihood conditions of forest dwellers through different forestry extension programs. Since its outset, many PFM programs have been conducted within the context of Madhupur Sal forest. Scientific studies have examined PFM contexts using a wide range of indicators, focusing on outcomes such as change in forest coverage, change in income level, poverty reduction and livelihood improvement to evaluate the impact of a PFM program. Few studies have also focused on institutional analysis and looked at formal and informal institutions and their role in natural resource management. According to scientific evidence, the impacts of PFM programs on livelihood and forest improvement remain contested. Despite the execution of different PFM programs over the last two decades in Madhupur Sal forest, the forest area reduced dramatically, the livelihood of forest dwellers became more vulnerable and forest dwellers engaged in conflicts with officials of the forest department (FD) concerning their rights. In the past, most studies considered that problem from the narrow perspective of a lack of knowledge or empowerment of forest dwellers without systemic consideration of forest development agencies, and the roles of other actors in PFM. To date, there is still limited research which considers the capacity issue at the individual, organizational, and enabling environment level. An improved understanding of the role of peoples capacity level is, however, vital to guide future PFM programs. Therefore, this study considers the PFM context from a holistic perspective that focuses not on forest dwellers but other actors within this system. Thus, the objectives of this study are: (1) to determine the changes in capacity level of participants in PFM programs and to explore the factors that influence changes in capacity level of forest dwellers, (2) to assess the role and performance of the pluralistic forest advisory systems, and (3) to explore the potential of a rights-based approach to create an enabling environment for collaborative action and cooperative conflict management. This thesis is composed of five chapters. The introductory chapter provides background information, the problem statement, the main research objectives, information about the study area and population, the theoretical embedding, and presents the outline of the thesis. The thesis combines qualitative and quantitative methods for collecting and analyzing data to deal with the three interrelated research objectives. The work on the first objective is based on a mixed methods approach (face-to-face survey, focus group discussions, key informant interviews, and participatory observation). The second objective is pursued using qualitative methods (stakeholder analysis, semi-structured interviews, participatory workshops) while the third objective is followed employing a case study approach. In Chapter 2, a modified analytical framework is used to explore the assertion that capacity is the outcome of a process-oriented approach like PFM. This revised framework combines different components of social learning platforms with essential components derived from a capacity development framework developed by the Tropical Agriculture Platform (TAP). Key capacities include the capacity to navigate complexity, capacity to collaborate, capacity to learn and reflect, and capacity to engage in political and strategical processes. Changes in the capacity level of forest dwellers were investigated with regard to the PFM initiative Re-vegetation of Madhupur Forests (RMF). The findings show that this PFM approach has brought desired changes in different dimensions of capacity development, i.e., capacity to collaborate, capacity to learn and reflect, and capacity to engage in strategic and political processes. The initiative did not bring changes to the capacity to navigate complexity. Furthermore, the long-run engagement and a range of participatory activities with different development organizations increased the understanding of participants and kept them up-to-date about their rights in forest management. The results also reveal that the FD worked through existing social capital within the community and took initiatives like several group discussions and meetings with the tribal community and their leaders before the RMF program. This initiative resulted in a common consensus of the tribal forest dwellers and reduced conflicts between FD and tribal forest dwellers. Findings regarding factors that influence changes in the capacity level of forest dwellers reveal that extension services, credit support, trust within society, information and communication influence the level of capacities to adapt and respond to changes among the tribal forest dwellers. Chapter 3 presents the role and performance of a pluralistic forest advisory system, considering the influence and importance of advisory service providers for managing natural resources, their organizational characteristics, and their service quality. A stakeholder analysis was conducted to identify advisory organizations along with the dynamics of power relations with forest dwellers. A best-fit framework was used to explore the characteristics and service quality of the existing organizations. The findings reveal that a range of organizations including public, private, and social organizations was working with tribal forest dwellers and followed the common objective of improving forest management and the livelihoods of the local forest dwellers. Also, a number of organizations involved in the provision of advisory services were still struggling with lack of capacities such as a limited number of advisors, lack of training facilities for the advisors and a lack of need-based technological contents. The findings further reveal that the FD had limited linkages and partnerships with other actors at the local level, despite being a central coordinating and executing agency for furthering forest policies and programs. At the same time, analysis of the organizational pluralism highlights that some NGOs worked for the livelihood improvement of forest dwellers by providing a range of technologies and information. Here, social organizations collaborated closely with forest dwellers and provided necessary information about the rights of forest dwellers. The overall assessment suggests that public sector organizations should take more proactive roles in integrating the important services of NGOs and other social organizations with forest dwellers within the pluralistic system. The study on exploring the potential of the rights-based approach to creating an enabling environment (chapter 4) reveal that neglecting rights of the forest dwellers before the initiation of RMF program led to ineffective policies and programs and subsequently to long-running conflicts. Different development programs implemented by the FD without any prior concern of tribal forest dwellers rights and interests, such as social forestry, eco-park and rubber garden establishment, became subject to conflicts. Results further revealed that several tribal forest dwellers died due to the clashes with the police when they steered the action of social movements for the sake of their rights. Tribal forest dwellers experienced top-down, non-cooperative, and even aggressive interventions from the FD which brought uncertainties into their daily lives. In contrast, participants of the RMF program reported that the FD initiated several meetings with tribal people and their leaders to know about their needs and expectations and engaged them in RMF program by offering several promises. During the execution of the RMF program, the FD contributed to welfare provisions like financial support, jobs, training, social forestry plots, healthcare cards, and similar offers. The results also reveal that the FD acknowledged different non-material issues like mutual respects, mobility in the forest, freedom to make decisions as a community forest worker, individual and social security, harassment-free life, access to information and regular communication between FDs and forest dwellers. Based on the above findings, this study provides some recommendations for the future design and implementation of PFM in Bangladesh which are: (i) the government should integrate the rights-based approach in the policy development since this can transform long-run disputes into collaborative action; (ii) more attention needs to be paid by the FD for the establishment of coordinated advisory services with other advisory service providers; (iii) the importance and influence of social organizations to mobilize the tribal forest dwellers towards cooperation and action should not be overlooked by the FD; (iv) any participatory forest management intervention in the future should be designed in such a way that it implies changes in the capacity level of the forest-dependent people, (v) the FD should integrate other public sector organizations in the provision of advisory services for forest management, because they are providing a range of technologies and information and working closely with forest dwellers, and (vi) the Government should move away from one-size-fits-all thinking to a best fit thinking.Diese Arbeit untersucht den Participatory Forest Management (PFM) Ansatz im Kontext des Madhupur Sal Waldgebiets in Bangladesch. Seit zwei Jahrzehnten ist PFM in Bangladesch das wichtigste politische Instrument zur Bewirtschaftung der natĂŒrlichen WaldflĂ€chen. Die gegenwĂ€rtige nationale Forstpolitik in Bangladesch betont die Bedeutung der Beteiligung verschiedener Akteure, insbesondere der Waldbewohner, am Forstwirtschaftsprogramm. Das ĂŒbergeordnete Ziel des PFM ist es, die Kompetenzen zu stĂ€rken und den Lebensunterhalt der Waldbewohner durch verschiedene forstliche Beratungsprogramme zu sichern und zu verbessern. Seit 1980 wurden mehrere PFM-Programme im Madhupur Sal Waldgebiet durchgefĂŒhrt. Wissenschaftliche Studien haben den PFM Ansatz dabei anhand einer Reihe von Indikatoren und Ergebnissen untersucht, z.B. die Verbesserung der Lebensgrundlage, ArmutsbekĂ€mpfung, VerĂ€nderung der Waldbedeckung und des EinkommensÂŹniveaus, um die VerĂ€nderungen und Wirkungen der PFM-Programme zu bewerten. Nur wenige Studien konzentrierten sich dabei auf die institutionelle Analyse. Diese befassten sich sowohl mit formalen als auch mit informellen Institutionen und deren Rolle im Management natĂŒrlicher Ressourcen. Nach wissenschaftlichen Erkenntnissen sind die Wirkungen der PFM-Programme auf die Verbesserung der Lebensgrundlage und die Verbesserung des Waldes umstritten. Trotz der verschiedenen PFM-Programme in den letzten zwei Jahrzehnten im Madhupur Sal Wald hat sich die WaldflĂ€che drastisch reduziert, die Lebensgrundlage der Waldbewohner ist noch mehr gefĂ€hrdet, und die Waldbewohner befinden sich bezĂŒglich ihrer Rechte im Konflikt mit der Forstbehörde. In der Vergangenheit betrachteten die meisten Studien dieses Problem aus einer engen Perspektive als fehlendes "Wissen oder empowerment" der Waldbewohner ohne BerĂŒcksichtigung der Rolle von ForstentwicklungsÂŹorganiÂŹsationen und anderen Akteuren als System. Zudem gibt es bisher nur begrenzte Forschungsarbeiten, die Fragen der KapazitĂ€t auf individueller und organisatorischer Ebene sowie das förderliche Umfeld berĂŒcksichtigen. Ein besseres VerstĂ€ndnis der FĂ€higkeiten der Waldbewohner ist von entscheidender Bedeutung fĂŒr das Gelingen zukĂŒnftiger PFM-Programme. Daher betrachtet diese Studie den PFM-Ansatz aus einer ganzheitlichen Perspektive, die nicht nur die Waldbewohner, sondern auch andere Akteure in diesem System berĂŒcksichtigt. Damit sind die Ziele dieser Studie: (1) die VerĂ€nderungen des KapazitĂ€tsniveaus bzw. die BefĂ€higung der Teilnehmer, sich an PFM-Programmen zu beteiligen und die Faktoren zu erforschen, die die VerĂ€nderungen dieser FĂ€higkeiten der Waldbewohner beeinflussen; (2) die Rolle und Leistung des pluralistischen Beratungssystems zur Förderung einer nachhaltigen Waldnutzung zu bewerten; und (3) das Potenzial eines rechtebasierten Ansatzes zu erforschen, um ein gĂŒnstiges Umfeld fĂŒr kooperatives Handeln und kooperatives Konfliktmanagement zu schaffen. Diese Arbeit besteht aus fĂŒnf Kapiteln. Das einleitende Kapitel enthĂ€lt Hintergrundinformationen, die Problemstellung, die PrĂ€sentation der wichtigsten Forschungsziele, Informationen ĂŒber das Untersuchungsgebiet und die Bevölkerung, die theoretische Einbettung und den Überblick ĂŒber diese Arbeit. Die Arbeit kombiniert qualitative und quantitative Methoden fĂŒr die Erhebung und Analyse der Daten zur Erreichung der drei miteinander verbundenen Forschungsziele. FĂŒr die Bearbeitung des ersten Forschungsziels wird ein mixed-method Ansatz verwendet (Face-to-Face-Umfrage, Fokusgruppen-Diskussion, Interviews mit SchlĂŒsselinformanten und partizipative Beobachtung), fĂŒr das zweite qualitative Methoden (Stakeholder-Analyse, halbstrukturierte Interviews, partizipativer Workshop) und fĂŒr das dritte Ziel ein Fallstudienansatz. Im zweite Kapitel wird der analytischen Rahmen vorgestellt. Dieser wird verwendet zur Untersuchung der Annahme, dass die Ausbildung von HandlungsfĂ€higkeiten das Ergebnis eines prozessorientierten Ansatzes wie PFM ist. Dieses Rahmenkonzept kombiniert verschiedene Komponenten der sozialen Lernplattform mit Komponenten des von der Tropical Agriculture Platform (TAP) entwickelten Capacity Development Framework. Zu den hier genannten SchlĂŒsselqualifikationen gehören die FĂ€higkeit, KomplexitĂ€t zu bewĂ€ltigen, die FĂ€higkeit zur Zusammenarbeit, die FĂ€higkeit zu lernen und zu reflektieren sowie die FĂ€higkeit, sich an politischen und strategischen Prozessen zu beteiligen. Die empirischen Untersuchungen bezĂŒglich der VerĂ€nderungen der SchlĂŒsselqualifikationen bei dem an der PFM-Initiative "Re-vegetation of Madhupur Forests (RMF) teilnehmenden Waldbewohnern zeigten, dass der PFM-Ansatz gewĂŒnschte VerĂ€nderungen in verschiedenen Dimensionen von KapazitĂ€ten mit sich bringt. Konkret wurde die KooperationsfĂ€higkeit, die Lern- und ReflexionsfĂ€higkeit und die FĂ€higkeit sich an strategischen und politischen Prozessen zu beteiligen verĂ€ndert, allerdings nicht die FĂ€higkeit KomplexitĂ€t zu bewĂ€ltigen. Das langfristige Engagement und eine Reihe von partizipativen AktivitĂ€ten erhöhten das VerstĂ€ndnis der Teilnehmer fĂŒr die nachhaltige Waldnutzung und hielten sie ĂŒber ihre Rechte im Forstmanagementsystem auf dem Laufenden. Die Ergebnisse zeigen auch, dass die Forstbehörde das bestehende Sozialkapital innerhalb der Gemeinschaft nutzte und bereits Initiativen vor dem RMF-Programm ergriff, die die Entwicklung eines gemeinsamen Konsens mit den Waldbewohnern förderten und Konflikte zwischen der Forstbehörde und den Waldbewohnern reduzierten. Faktoren, die die VerĂ€nderungen des KapazitĂ€tsniveaus der Waldbewohner positiv beeinflussten, waren Beratungsleistungen, KreditunterstĂŒtzung, Vertrauen in die Gesellschaft, und Information und Kommunikation zur Anpassung an und Umgang mit VerĂ€nderungen. Kapitel 3 befasst sich mit der Rolle und den Leistungen des pluralistischen Beratungssystems unter BerĂŒcksichtigung des Einflusses und der Bedeutung von Beratungsdienstleistern fĂŒr das Management natĂŒrlicher Ressourcen, ihrer organisatorischen Merkmale und ihrer ServicequalitĂ€t. Eine Stakeholder-Analyse wurde durchgefĂŒhrt, um die Beratungsorganisationen und ihrem Einfluss zu identifizieren. Der " best-fit" Framework wurde verwendet, um die Merkmale und die ServicequalitĂ€t der bestehenden Organisationen zu untersuchen. Die Ergebnisse zeigen, dass eine Reihe von Organisationen, darunter öffentliche, private und soziale Organisationen, mit Waldbewohnern zusammen arbeiteten, um die Waldbewirtschaftung und die Lebensgrundlage der lokalen Waldbewohner zu verbessern. Eine Reihe von Organisationen, die an der Erbringung von Beratungsdienstleistungen beteiligt waren, hatten allerdings immer noch mit mangelnden KapazitĂ€ten zu kĂ€mpfen, darunter eine begrenzte Anzahl von Beratern, fehlenden Ausbildungsmöglichkeiten fĂŒr diese und fehlende bedarfsorientierte, technologische Inhalte. Die Ergebnisse zeigen weiter, dass die Forstbehörde nur begrenzte Verbindungen und Partnerschaften mit anderen Akteuren auf lokaler Ebene hatte, obwohl sie ein zentraler Koordinator und TrĂ€ger fĂŒr die Förderung der Forstpolitik und -programme ist. Auf der anderen Seite hat die Analyse des organisatorischen Beratungspluralismus auch gezeigt, dass einige NGOs durch die Bereitstellung von Technologien und Informationen zur Verbesserung der Lebensgrundlage der Waldbewohner beigetragen haben, wobei die sozialen Organisationen in enger Zusammenarbeit mit den Waldbewohnern notwendige Informationen ĂŒber ihre Rechte zur VerfĂŒgung gestellt haben. Die Gesamtbewertung legt nahe, dass Organisationen des öffentlichen Sektors eine proaktive Rolle bei der Integration von NGOs und anderen sozialen Organisationen mit Waldbewohnern innerhalb des pluralistischen Systems spielen. Die im vierten Kapitel vorgestellte Studie ĂŒber die Erforschung des rechtebasierten Ansatzes zur Schaffung eines unterstĂŒtzenden Umfelds (enabling environment) zeigt, dass die VernachlĂ€ssigung der Rechte der Waldbewohner vor der Aufnahme des RMF-Programms zu ineffektiven Richtlinien und Programmen und nachfolgenden und langanhaltenden Konflikten fĂŒhrte. Verschiedene Entwicklungsprogramme, die von der Forstbehörde ohne vorherige RĂŒcksichtnahme der Waldbewohner durchgefĂŒhrt wurden, fĂŒhrten dazu, dass Entwicklungsprogramme zur Sozialen Forstwirtschaft, zur Einrichtung eines Ökoparks und eine Gummiplantagenanlage Gegenstand von Konflikten wurden. Die Situation verschĂ€rfend wirkte ferner, dass mehrere Waldbewohner durch ZusammenstĂ¶ĂŸe mit der Polizei starben, als sie sich in der soziale Bewegung zur Verteidigung ihrer Rechte engagierten. So erlebten die Waldbewohner dass top-down gefĂŒhrte, unkooperative und sogar aggressive Eingriffe der Forstverwaltung auf vielfĂ€ltige Weise Unsicherheit in ihren Alltag brachten. Im Gegensatz dazu berichteten die Teilnehmer des RMF-Programms, dass die Forstbehörde mehrere Treffen mit den lokalen Waldbewohnern und ihren AnfĂŒhrern durchfĂŒhrte, um die BedĂŒrfnisse und Erwartungen kennen zu lernen, und mehrere Versprechungen im Hinblick auf die Entwicklungsförderung zu geben. WĂ€hrend der DurchfĂŒhrung des RMF-Programms leistete die Forstbehörde Sozialhilfe wie finanzielle UnterstĂŒtzung, Arbeit, Ausbildung, die EinfĂŒhrung sozialer Forstwirtschaft und einer Gesundheitskarte. Die empirischen Ergebnisse zeigen weiter, dass die Forstbehörde auch verschiedene nicht-materielle Themen wie gegenseitige Achtung, MobilitĂ€t im Wald, Entscheidungsfreiheit als kommunale Waldarbeiter, individuelle und soziale Sicherheit, belĂ€stigungsfreies Leben, Zugang zu Informationen und regelmĂ€ĂŸige Kommunikation der Waldbewohner gefördert hat. Basierend auf den oben genannten Ergebnissen aus den drei Teiluntersuchungen liefert die vorliegende Arbeit eine Reihe politischer Empfehlungen fĂŒr die zukĂŒnftige Gestaltung von PFM-AnsĂ€tzen in Bangladesch. ZunĂ€chst sollte die Regierung den rechtebasierten Ansatz in den politischen Diskurs integrieren, da dieser Ansatz langfristige Streitigkeiten in kooperatives Handeln umwandeln kann; zweitens wird empfohlen, dass die Forstbehörde der Einrichtung koordinierter Beratungsdienstleistungen mit anderen Beratungsdienstleistern unter BerĂŒcksichtigung der Bedeutung, der Merkmale und der ServicequalitĂ€t der bestehenden Organisationen mehr Aufmerksamkeit schenken soll; drittens darf die Bedeutung und der Einfluss sozialer Organisationen fĂŒr die Mobilisierung der Waldbewohner zur Zusammenarbeit durch die Forstbehörde nicht vernachlĂ€ssigt werden; viertens sollte jede partizipative Waldbewirtschaftung in Zukunft so konzipiert werden, dass sie VerĂ€nderungen der HandlungsfĂ€higkeiten der vom Wald abhĂ€ngigen Menschen bewirken kann, und fĂŒnftens sollte die Forstbehörde öffentliche Organisationen in die Erbringung von Beratungsdiensten einbeziehen, und schließlich wird fĂŒr die kĂŒnftige Politikgestaltung empfohlen, dass die Regierung von einem " One-size-fits-all " zu einem " Best Fit " Konzept ĂŒbergehen möge

    Addressing English Phobia among the Secondary School Students in the Rural Area of Bangladesh

    Get PDF
    Second / Foreign Language (S/FL) learning efforts always create tremendous mental pressure on the learner. It is never acquired effortlessly like one’s native language. Naturally it creates anxiety among the learners which ultimately causes phobia among those who desire to acquire an S/FL. If learners fail to facilitate this anxiety, it increasingly dominates and creates phobia. When this phobia gets severe, learners ultimately give up S/FL learning pursuit. It is a very common phenomenon in Bangladeshi secondary schools especially in the rural areas when they learn English as a foreign language. This study, therefore, investigates the causes behind English phobia among the students of the rural areas of Chittagong, Bangladesh. Here, through this study, I seek to explore the challenges of our learners and to find a solution to this problem. In order to find out the causes behind English phobia, I have used mixed method research. I have used questionnaires as well as arranged interview with the participants with a view to finding out factors that function as impediments to learning English. The analysis of the data shows that the phobia is caused by students’ lack of motivation, confidence and aptitude resulting from the inefficient teaching methodologies

    Automatic inductive theorem proving and program construction methods using program transformation

    Get PDF
    We present new approaches to prove universally and existentially quantified conjectures and to construct programs from the resulting proofs. These theorem proving and program construction techniques make use of the distillation algorithm to transform input conjectures into a normalised form which we call distilled form. The proof rules are applied to the resulting distilled program. Our theorem proving and program construction techniques have been implemented in a theorem prover which we call Poitin. We give an overview of the distillation algorithm, and then present the proof and program construction techniques implemented in Poitin. Our implementation of the proof and program construction techniques used in Poitin is then presented. The soundness of the proof technique is shown with respect to a logical proof system using sequent calculus. We show that the constructed programs are correct with respect to their specification. The main contributions of this thesis can be summarised as follows. First, we present fully automatic, and efficient inductive theorem proving techniques. Second, we present a novel program construction technique to construct correct programs. Third, we have shown how automatic program transformation can be used in a novel way in an inductive theorem prover. Finally, the use of distillation to obtain a normal form of the input program reduces over-generalization and generation of non-theorems. We have implemented the theorem prover and demonstrated it on some examples. The use of distillation in the framework of Poitin has eased the automation of the proof and program construction techniques in a reduced search space to make it fully automatic and efficient

    Planning for scanning in construction : optimizing 3D laser scanning operations using building information modelling and a novel specification on surface scanning completeness.

    Get PDF
    Application of Terrestrial Laser Scanning (TLS) technology in the Architectural Engineering and Construction (AEC) industry is gaining popularity because the technology uniquely offers the means to create as-built three-dimensional (3D) models of existing facilities, and conduct construction project progress and dimensional quality measurements. An open challenge with regard to the use TLS for such applications is to efficiently generate effective scanning plans that satisfy pre-defined point cloud quality specifications. Two such specifications are currently commonly used: Level of Accuracy (LOA) that focuses on individual point precision, and Level of Detail (LOD) that focuses on point density. Given such specifications, current practice sees professionals manually prepare scanning plans using existing 2D CAD drawings, some ad-hoc rules (of thumb), and their experience. Yet, it is difficult to manually generate and analyse laser scanning plans to ensure they satisfy scanning quality specifications such as those above. Manually-defined plans may easily lead to over-scanning, or worse under-scanning with incomplete data (which may require the team to go back on site to acquire complementary data). To minimize the risk of producing inadequate scanning plans, some semi-automated and automated methods have been proposed by researchers that use the 3D (BIM) model generated during the design stage. These methods take consideration for LOA and LOD. However, these are point-based specifications that do not guarantee that a sufficient amount of the surface of each object is covered by the acquired data, despite this aspect being important to many of the applications for which TLS is employed (e.g. modelling existing facilities). Therefore, this research uniquely proposes a novel planning for scanning quality specification, called Level of Surface Completeness (LOC) that assesses point cloud quality in terms of surface completeness. In addition, an approach is proposed for automatic planning for scanning in the AEC industry that takes both LOA and LOC specifications into account. The approach is ‘generic’ in the sense that it can be employed for any type of project. It is designed to generate automatic laser scanning plans using as input: (1) the facility’s 3D BIM model; (2) the scanner’s characteristics; and (3) the LOA and LOC specifications. The output is the smallest set of scanning locations necessary to achieve those requirements. The optimal solution is found by formulating the problem as a binary integer programming optimization problem, which is easily solved using a branch-and-cut algorithm. To assess the performance of the approach, experiments are conducted using a simple concrete structural model, a more complex structural model, and a section of the latter extended with Mechanical Electrical and Plumbing (MEP) components. The overall performance of the proposed approach for automatic planning for scanning is encouraging, showing that it is possible to take surface-based specifications into account in automated planning-for-scanning algorithms. However, the experimental results also highlight a significant weakness of the approach presented here which is that it does not take into account the overlapping of surfaces covered from different scanning locations and thus may inaccurately assess covered surfaces

    Crop growth and water-use from saline water tables

    Get PDF
    PhD ThesisHow much water can a crop abstract from below a saline water table and how does the salinity affect yield? These questions are important because shallow groundwater may represent a substantial resource in flat, low-lying areas, but may also represent a threat to sustainability where salinity is high. A series of experiments in a glasshouse aimed to elucidate irrigation management practice under salinity conditions and to develop a root uptake model under both osmotic and matric stresses. The extraction of soil water and groundwater by lettuce and perennial ryegrass crops were measured in three instrumented lysimeters. Water table depths were 0.6,0.9 and 1.2 rn below the soil surface. The lysimeters were initially saturated with saline water (electrical conductivity 4.5 dS m- 1 for lettuce, 9.4 dS m- I for the first crop of ryegrass and 0.4,7.5 & 15.0 dS m-1 for the second crop of ryegrass) and drained until an equilibrium soil water profile was attained. Water with the same electrical conductivity was then supplied by Marione siphons to maintain the constant water table. The water table contribution was recorded and water losses from the soil profile were estimated from daily readings of soil water potential using tensiometersa; nd gypsum blocks. Solute samples were extracted periodically for salinity measurement. The cropping period of lettuce was 90 days from sowing and the lst & 2nd cropping periods of ryegrass were 223 & 215 days respectively. The first ryegrass experiment showed that the water table depth (60,90 and 120 cm) did not have significant contribution (37,36 and 36 mm) on either total soil moisture use or groundwater contribution. Similar results were found for total soil moisture use for lettuce, though the groundwater contribution varied significantly. The second ryegrass experiment showed that salinity at the water table strongly influenced total soil moisture use, but the total groundwater contribution varied only slightly. The overall crop experiments show that the groundwater contribution was within the range of 25-30% of the total water use, except for the 15 dS m7l treatment where the contribution was greater than the soil moisture use. Groundwater contribution rate was higher when the plants were subjected to more osmotic and matric stresses. Yield component data show that increasing salinity leads to a reduction in total yield, but the drymatter proportion was higher. Higher salinities occurred in the upper 15 cm of the root zone, because of the greater soil moisture depletion. Below that depth the salinization rate was smaller, because of the greater groundwater contribution in the later part of the season. There is reasonable agreement between measured and estimated (based on convective transport theory) values soil salinity. Salinities increased in the root zone by about 3-fold of initial salinity for lettuce and around 4-fold for ryegrass in the top 5 cm depth, but below 15 cm depth it was less than 2 fold. Finally, a simplified model was developed to describe the interaction of root-zone salinity and water uptake, considering salinity and water stress as additive. The model shows that the higher the root-zone salinity stress, the higher the predicted water uptake while plant uptake considered -1.5 MPa. This variation is ranged from 4 to 17% for 0.4 to 9.4 dS m-1 and 30 % for 15 dS m-1. The model was developed in a climate with low atmospheric demand, but needs testing in a more severe environment.Bangladesh Agricultural Research Council (BARC) / IDA, World Bank