63,636 research outputs found

    A Forward Reachability Algorithm for Bounded Timed-Arc Petri Nets

    Full text link
    Timed-arc Petri nets (TAPN) are a well-known time extension of the Petri net model and several translations to networks of timed automata have been proposed for this model. We present a direct, DBM-based algorithm for forward reachability analysis of bounded TAPNs extended with transport arcs, inhibitor arcs and age invariants. We also give a complete proof of its correctness, including reduction techniques based on symmetries and extrapolation. Finally, we augment the algorithm with a novel state-space reduction technique introducing a monotonic ordering on markings and prove its soundness even in the presence of monotonicity-breaking features like age invariants and inhibitor arcs. We implement the algorithm within the model-checker TAPAAL and the experimental results document an encouraging performance compared to verification approaches that translate TAPN models to UPPAAL timed automata.Comment: In Proceedings SSV 2012, arXiv:1211.587

    The mutuality of care

    Get PDF
    Steinhoff Smith, Roy Herndon. The mutuality of care. St Louis: Chalice Press, 1999

    Introducing farmer group learning and development into organic small holder farming systems in the global south -including a case study from the state of Madhya Pradesh, India.

    Get PDF
    On most continents food production has surpassed the growth in population (Knudsen et al. 2006). Still it is estimated that approximately 1 billion people are undernourished (FAO 2011) and the greatest number of people suffering from chronic hunger are living in South and East Asia (FAO 2012a). More than half (3.1 billion people) of the developing world’s population live in rural areas. Of these, approximately 2.5 billion derive their livelihoods from agriculture (FAO 2012a). The majority of small scale farmers in the global south lack financial and natural resources to be able to improve production and food security (Knudsen et al. 2006). A United Nations’ report on organic agriculture and food security concludes that organic agriculture increases the availability and access of food in the location where hunger and poverty are most severe (FAO 2007). According to UNEP (United Nations Environmental Program) non-certified organic practices in Africa outperforms conventional industrialized agriculture and provides improved soil fertility, retention of water as well as resistance to drought (UNEP 2008). The Millennium Development Goals are targeting sustainable agriculture specifically (United Nations 2009) and in the report by the IAASTD panel, focus on small scale farmers and the use of sustainable agricultural practices are recommended (IAASTD 2008). Organic farming emerged in the 1920s with the concept of an inextricable link between soil, plant and animal health and of the composting process as an important element to obtain this. Hence artificial fertilizer was looked upon with great concern. In the 1960s and 1970s organic farming faced a turning point due to the negative consequences of industrial farming methods including the use of chemical substances. The work of many volunteers, heavily engaged in organic farming, led to the foundation of the International Federation of Organic Agriculture Movements (IFOAM) in 1972 (Kristiansen & Merfield 2006). IFOAM has formulated four basic principles: Principle of health, ecology, fairness and care. They serve to inspire the organic movement, are the basis from where standards are developed and are presented with a vision of world-wide adoption (IFOAM 2005). According to IFOAM organic agriculture is: “A production system that sustains the health of soils, ecosystems and people. It relies on ecological processes, biodiversity and cycles adapted to local conditions, rather than the use of inputs with adverse effects. Organic agriculture combines tradition, innovation and science to benefit the shared environment and promote fair relationships and a good quality of life for all involved” (IFOAM 2008). Frequently, in the global south, the meaning of organic agriculture is confused with “farming without chemical inputs”, “traditional farming” or “certified organic farming for export purposes” (Vaarst 2010). In this assignment organic agriculture is defined by the above mentioned four basic principles and description of organic farming. This includes the use of agro-ecological methods in agricultural systems which do not necessarily have to be certified organic. 2 Agro-ecological methods include the use of compost and legumes to improve soil fertility. Mulching conserves soil moisture and suppresses weeds. Intercropping increases yields and keeps the soil covered, hence preventing soil erosion and promoting soil moisture. Crop rotation with high species diversity prevents pests and diseases from building up as well as contributing to a diversified diet. Agroforestry is less affected by drought (deep root system). At the same time it increases soil porosity, reduces runoff and increases soil cover leading to increased water infiltration and retention in soil (Nakasi et al. Unknown; Vaarst 2010). Livestock are an integrated part of organic agriculture supporting biological cycles within the system, in particular nutrient recycling (Hermansen 2003). Another important aspect is that organic farming does not rely on input of costly artificial fertilizers and chemicals. High inputs can force farmers to borrow money from private lenders with high interest rates. Hence farmers are vulnerable if the harvest fails (Halberg et al. 2006). Also pesticides can lead to poisoning when applying it and through accidents (Pretty 1995 cf. Halberg et. al. 2006). Conscious use of agro-ecological methods requires many skills, a lot of knowledge, assessment and planning (Vaarst et al. 2012). Therefore it is relevant to create a situation where knowledge can be exchanged, developed and debated (Vaarst et al. 2011). Organic farming is labour intensive, for example it requires labour to make compost, dig trenches, mulch and weed (Vaarst et al. 2011). Farmer Family Learning Groups (FFLG) creates a situation where farmers and their families go together to share their knowledge and experiences as well as help each other perform labour demanding tasks (Vaarst et al. 2011). Organic farming and Farmer Field Schools (FFS) is a way to assist vulnerable groups to empower themselves to claim their rights and have access to resource mechanisms (FAO 2007). The objective of this assignment is to evaluate the benefits and barriers of introducing farmer group learning and development into organic small holder farming systems in the global south. The farmer group learning is exemplified by the concepts of FFS and FFLG. The first section describes the concept of FFS and FFLG. Afterwards benefits and barriers of introducing FFS and FFLG are presented. Finally a case study from three districts in Madhya Pradesh, India is reviewed and analysed in terms of introducing farmer group learning

    Contraception, Abortion and Assisted Fertility Among Muslim Women A Look at Islamic Culture and Policy in Iran and Afghanistan

    Get PDF
    Discourse on women\u27s reproductive rights through the lens of Muslim culture. The use of contraception, assisted fertility and abortion, are analyzed in Iran and Afghanistan. The culture surrounding family planning is detailed through a woman’s community, family, religion and the laws that govern the society they live in, which all influence her decision making in these matters. This piece stands as a cultural analysis of women\u27s agency specifically in Middle Eastern Muslim culture, as it stands as a part of a global women\u27s rights movement

    Building knowledge for Aboriginal and Torres Strait Islander remote tourism: lessons from comparable tourism initiatives around the world

    Get PDF
    This report aims to build knowledge about what issues Aboriginal and Torres Strait Islander people may need to consider in remote tourism by reviewing, compiling and drawing insights from comparable tourism initiatives around the world.The report is based on information from a range of sources that highlight remote tourism issues at many different levels of strategy and development , from the micro level of ensuring engagement with local service providers, to the broad level of collaboration strategies with diverse interest groups. The examples identify a wealth of remote tourism roles available to Aboriginal and Torres Strait Islander people, demonstrating that remote tourism is complicated and people should examine which roles are appropriate and achievable.The report covers the main remote area landscape settings: remote arid and semi-arid areas (deserts), remote rainforests, remote high altitude mountainous areas, and remote cold and warm water islands. Each section discusses a collection of cases and other tourism initiatives by people s indigenous to the respective remote landscape settings. Many cases illustrate the desires of people around the world to preserve natural and cultural qualities while sharing remote areas through tourism. Summaries from each case identify issues that progressively build further insight into the challenges and strategies people from around the world have applied to remote tourism.A limitation of the report is that the review provides a snapshot of remote tourism activity throughout the world; it has not been able to say which of these activities are sustainable. Nevertheless, this approach uncovers the gravity of challenges faced by Indigenous peoples around the world involved in remote tourism, with the common dependence on external sources particularly noted. While presenting the strategies used in the various international contexts to contend with the challenges, the report suggests that local knowledge and insight cannot be underestimated as a major factor in developing successful Aboriginal and Torres Strait Islander tourism businesses

    The longing for utopia : trends in life-long adult education in a highly developed, technological society

    Get PDF
    In our world system there exists an inter- national division of labour between the so-called underdeveloped countries of the third world and the so-called highly developed countries, which might properly be termed: 'over-developed'. Contrary to much popular belief, serious social defects are to be found in the over-developed countries. Among these defects are: alienation, individual isolation, dissolution: of family life, stress, value crises, instrumentalism, emotional unhappiness, resignation and hopelessness as to the future.peer-reviewe

    Clinical pastoral supervision and the theology of Charles Gerkin

    Get PDF
    O\u27Connor, Thomas St James. Clinical pastoral supervision and the theology of Charles Gerkin. Waterloo, Ont: WLU Press, 1998

    Top Mass from Electroweak Measurements

    Get PDF
    The electroweak measurements made at LEP using 1989-1993 data are presented in preliminary form. The agreement with the Standard Model is satisfactory, and allows a combined fit to all available data for the masses of the top quark and standard Higgs boson. The fit yields M_t = 177 +11 -11 +18 -19 GeV/c2, where the second error reflects the uncertainty in the Higgs mass. Talk given at the XXIXth Rencontre de Moriond, `QCD and High Energy Hadronic Interactions', March 1994, Meribel FranceComment: 8 pages, 330K uufiled Postscript, preprint CERN-PPE/94-9
    corecore