93 research outputs found

    Requirements elicitation interviews and applications for an underground remote-piloted aerial system

    Get PDF
    Abstract: Being underground is dangerous, it really is. People shouldn’t go there if they don’t need to, especially in an age where driverless cars by Google and shopping delivery by Amazon are on the brink of implementation in unstructured public environments; but held up, not by technology, but by wrangling about legislation covering liability determination, and fears of hacking drive-by-wire systems. Underground mining is a secure (from an IT perspective), structured, and predictable environment with limited and controlled human access – an ideal place for automated or remotely piloted systems. This paper outlines the semi-structured interview process that was executed to determine the requirements for an underground remotely piloted aerial system (URPAS). The potential applications are explored; including search and rescue, the business-orientated activity of regularly scanning rockpasses to predict and prevent blockages, and scanning a blocked rockpass to determine the blockage location and structure. An even more ’out-of-the-box’ application, using the vehicle to deliver explosives to the underside of a blockage, was included in the brainstorming discussions. Interviews with ten mining and unmanned aerial systems experts were conducted with a questionnaire as the primary data collection tool. The questionnaires were analysed to determine the representatively of the sample set, and therefore the validity of the gathered data, based upon expertise ratings in each of the relevant areas of knowledge: mining, surveying and mapping, and remote-piloted aerial systems. The goal was to identify the key performance requirements of a U-RPAS, and determine the feasibility of such a system being developed. A specialized company providing a scanning service emerged the preferred implementation method, and the rationale for this choice is presented. As context, the sub-system prototypes used in the brainstorming section of the interviews are presented, as are the implementation scenarios discussed in the interviews. It is thus shown that this method of requirements elicitation is suitable for this type of technology implementation project

    Evaluating camera trapping as a method for estimating cheetah abundance in ranching areas

    Get PDF
    In order to accurately assess the status of the cheetah Acinonyx jubatus it is necessary to obtain data on numbers and demographic trends. However, cheetahs are notoriously difficult to survey because they occur at very low population densities and are often shy and elusive. In South Africa the problem is further complicated in areas where land is privately owned, restricting access, with dense bush and cheetahs that are frequently persecuted. Cheetahs are individually identifiable by their unique spot patterns, making them ideal candidates for capture-recapture surveys. Photographs of cheetahs were obtained using four camera traps placed successively at a total of 12 trap locations in areas of known cheetah activity within a 300 km2 area in the Thabazimbi district of the Limpopo Province. During 10 trapping periods, five different cheetahs were photographed. These results were used to generate capture histories for each cheetah and the data were analysed using the capture-recapture software package CAPTURE. Closure tests indicated that the population was closed (P = 0.056). The Mh model was used to deal with possible heterogeneous capture probabilities among individual cheetahs. Closure tests did not reject the model assumption of population closure (P = 0.056). The Mh model produced a capture probability of 0.17 with an estimate of 6-14 cheetahs (P = 0.95) and a mean population size of seven cheetahs (S.E. = 1.93). These results are promising and will be improved with employment of more camera traps and sampling a larger area

    Requirements degradation for the creation of a first prototype

    Get PDF
    The requirements engineering process is typically executed, irrespective of the process model chosen, for the final commercially viable system. The system requirements generated are for a system deployed and used in its final form and function. However, the first prototype that is generated is typically representative of a minimum viable technology, and represents a degraded set of the initial system requirements specification. Typically, a first prototype is used as a technology demonstrator, and its failure or success will determine the continuation of the project, with success triggering the allocation of additional financial and personal resources. This paper explores techniques for requirements degradation that can be used to form the system requirements specification for the first prototype. A requirements Engineering methodology is proposed based upon a survey of literature. It takes into consideration the characteristics of the project, i.e. a market driven, technology implementation research project with limited budget and a flexible timeline executed in an academic environment. The techniques must take into cognizance the main risk items, and core requirements, that need to be demonstrated in the minimum viable technology to secure the future of the project. The degradation cannot undermine or jeopardize the future success of the commercially viable system in determining the subset of requirements for the minimum viable technology

    Factors affecting the performance of a manufacturing supply chain, and the organization

    Get PDF
    Abstract: Due to constant failure in delivering the products to customers on time the defence manufacturing organization introduced the supply chain phenomenon into its operations in an attempt to improve its performance (on-time delivery). This research aims to identify if supply chain performance is affected mainly by social or technical factors and also outline which of these factors have the highest effect on the performance of supply chain. The importance of this research is that it will determine if the performance of supply chain is affected by technical or social factors and also how the organization is affected by these factors. This research employed a case study and made use of both qualitative and quantitative data to allow for data triangulation in order to minimize biasness and increase the credibility of the results. The findings indicate that supply chain performance is affected by both social factors and technical factors, however the impact of these factors on both supply chain and the organization is different. In summary, this research will provide insight to the factors that affect the performance of supply chain and accordingly provide methods to minimize or eliminate these factors and therefore reducing their effect on supply chain and the organization

    Home ranges of cheetahs (Acinonyx jubatus) outside protected areas in South Africa

    Get PDF
    As many carnivores occur outside protected areas, they are vulnerable to anthropogenic threats. In South Africa, the largest proportion of the distribution range of cheetahs (Acinonyx jubatus) is outside protected areas along the northern border of the country. Lions (Panthera leo) and spotted hyaenas (Crocuta crocuta) have been extirpated from these areas, leaving the depauperate carnivore guild dominated by cheetahs, leopards (Panthera pardus) and brown hyaenas (Hyaena brunnea). To determine how cheetahs use these areas, tracking collars were fitted to nine individuals from September 2003 to July 2009 in the Thabazimbi area, Limpopo, South Africa. Local Convex Hulls (αLoCoH) were used to determine home range sizes and 50 and 95 utilization distributions (UDs) were calculated. Male 95UDs ranged from 121.5 km2 to 607 km2 while females ranged from 14.7 km2 to 703.3 km2. Cheetahs utilized several ranches and mean home ranges sizes were larger than mean ranch size and larger than cheetah home ranges recorded in other southern African countries, with the exception of the more arid Namibia. This study provides valuable and relevant data on cheetahs and aids conservation practitioners in mitigating human-cheetah conflict on South African farmland.Columbus Zoo, Cat Life Foundation, Duemke Family Trust, Scovill Zoo, Carston Springs Trust and the DST-NRF Centre for Excellence for Invasion Biology.http://www.sawma.co.zaam201

    Modulation of LPS-Induced CD4+ T-Cell Activation and Apoptosis by Antioxidants in Untreated Asymptomatic HIV Infected Participants: An In Vitro Study

    Get PDF
    Persistent immune activation characterises HIV infection and is associated with depletion of CD4+ T-cells and increased risk of disease progression. Early loss of gut mucosal integrity results in the translocation of microbial products such as lipopolysaccharide (LPS) into the systemic circulation. This is an important source of on-going immune stimulation. The purpose of this study was to determine levels of CD4+ T-cell activation (%CD25 expression) and apoptosis (% annexin V/7-AAD) in asymptomatic, untreated HIV infection at baseline and after stimulation with LPS and incubation with or without vitamin C and N-acetylcysteine. LPS induced a significant ( < 0.03) increase in %CD25 expression, annexin V, and 7-AAD in HIV positive individuals. NAC in combination with vitamin C, significantly ( = 0.0018) reduced activation and early apoptosis of CD4+ T-cells to a greater degree than with either antioxidant alone. Certain combinations of antioxidants could be important in reducing the harmful effects of chronic immune activation and thereby limit CD4+ T-cell depletion. Importantly, we showed that CD4+ T-cells of the HIV positive group responded better to a combination of the antioxidants at this stage than those of the controls. Therefore, appropriate intervention at this asymptomatic stage could rescue the cells before repetitive activation results in the death of CD4+ T-cells

    Fumonisin-induced hepatocarcinogenesis: mechanisms related to cancer initiation and promotion.

    Get PDF
    We review the hepatocarcinogenic effects of fungal cultures of Fusarium verticillioides(= Fusarium moniliforme) strain MRC 826 in male BD IX rats. Subsequent chemical analyses of the fumonisin B (FB) mycotoxin content in the culture material used and long-term carcinogenesis studies with purified FB1 provide information about dose-response effects, relevance of hepatotoxicity during FB1-induced carcinogenesis, and the existence of a no-effect threshold. Fumonisin intake levels of between 0.08 and 0.16 mg FB/100 g body weight (bw)/day over approximately 2 years produce liver cancer in male BD IX rats. Exposure levels < 0.08 mg FB/100 g bw/day fail to induce cancer, although mild toxic and preneoplastic lesions are induced. The nutritional status of the diets used in the long-term experiments was marginally deficient in lipotropes and vitamins and could have played an important modulating role in fumonisin-induced hepatocarcinogenesis. Short-term studies in a cancer initiation/promotion model in rat liver provided important information about the possible mechanisms involved during the initial stages of cancer development by this apparently nongenotoxic mycotoxin. These studies supported the findings of long-term investigations indicating that a cytotoxic/proliferative response is required for cancer induction and that a no-effect threshold exists for cancer induction. The mechanisms proposed for cancer induction are highlighted and include the possible role of oxidative damage during initiation and the disruption of lipid metabolism, integrity of cellular membranes, and altered growth-regulatory responses as important events during promotion

    Tracking data from nine free-roaming Cheetahs (Acinonyx jubatus) collared in the Thabazimbi area, Limpopo Province, South Africa

    Get PDF
    BACKGROUND : In partnership with the University of Pretoria, the Endangered Wildlife Trust's Carnivore Conservation Programme collared six male and three female free-roaming Cheetahs (Acinonyx jubatus) in the Thabazimbi area in Limpopo Province, South Africa. This study was undertaken to determine the spatial ecology of free-roaming Cheetahs that occur outside of formal protected areas on private ranchland, where they frequently come into conflict with, and are sometimes killed by, private landowners. The data were collected between September 2003 and November 2008, resulting in a total of 3165 location points (65 points from VHF collars and 3100 from GPS collars) for nine individual Cheetahs. NEW INFORMATION : This dataset provides distribution information about this Vulnerable species occurring outside of protected areas within South Africa. The dataset has been published to the Global Biodiversity Information Facility (www.GBIF.org) and provides the largest dataset on Cheetahs thus far, and, although it is spatially limited to a relatively small region on the African continent, it is the first study of its kind within South Africa. Also of significance is that the fate of 6 of the 9 collared Cheetahs is known, all except one of which died of anthropogenic causes.https://bdj.pensoft.netam2017Centre for Wildlife Managemen

    Tracking data from nine free-roaming Cheetahs (Acinonyx jubatus) collared in the Thabazimbi area, Limpopo Province, South Africa

    Get PDF
    BACKGROUND : In partnership with the University of Pretoria, the Endangered Wildlife Trust's Carnivore Conservation Programme collared six male and three female free-roaming Cheetahs (Acinonyx jubatus) in the Thabazimbi area in Limpopo Province, South Africa. This study was undertaken to determine the spatial ecology of free-roaming Cheetahs that occur outside of formal protected areas on private ranchland, where they frequently come into conflict with, and are sometimes killed by, private landowners. The data were collected between September 2003 and November 2008, resulting in a total of 3165 location points (65 points from VHF collars and 3100 from GPS collars) for nine individual Cheetahs. NEW INFORMATION : This dataset provides distribution information about this Vulnerable species occurring outside of protected areas within South Africa. The dataset has been published to the Global Biodiversity Information Facility (www.GBIF.org) and provides the largest dataset on Cheetahs thus far, and, although it is spatially limited to a relatively small region on the African continent, it is the first study of its kind within South Africa. Also of significance is that the fate of 6 of the 9 collared Cheetahs is known, all except one of which died of anthropogenic causes.https://bdj.pensoft.netam2017Centre for Wildlife Managemen

    The combination of red palm oil and rooibos show anti-inflammatory effects in rats

    Get PDF
    BACKGROUND: Red palm oil (RPO) and rooibos have been shown to exhibit cardioprotective properties. RPO is rich in essential fatty acids and fat soluble antioxidants while rooibos contains polyphenolic compounds with a unique composition of flavonoids. They exert their biological effects in different cellular compartments. Therefore the combination of these two natural food compounds has the potential to enhance the spectrum of available dietary antioxidants in different cellular compartments, which could result in an enhanced protection against certain pathological conditions such as inflammation. METHODS: Male Wistar rats weighing 150-200 g were supplemented with RPO, rooibos or their combination for 28 days. The Langendorff system and the lipoposaccharide (LPS)-induced inflammatory model were used to establish if RPO and rooibos, when supplemented alone or in combination, will reverse the negative effects of LPS on cardiac function at baseline. The effect of dietary intervention was also investigated on modulation of pro-inflammatory and anti-inflammatory cytokines in plasma and myocardial tissue. RESULTS AND DISCUSSION: The LPS resulted in induction of systemic inflammation as evidenced by increased levels of IL-1beta in plasma of LPS-treated rats compared to their non-treated control counterparts. Dietary supplementation and LPS treatment did not have an effect on baseline cardiac functional parameters. However, the elevation of IL-1beta levels in plasma of LPS-induced rats consuming either RPO or rooibos alone were paralleled with increased levels of the anti-inflammatory cytokine, IL-10. The combination of rooibos and RPO was associated with enhanced endogenous production of myocardial IL-10 in LPS-induced rats. CONCLUSION: The results of this study indicate that RPO and rooibos when supplemented individually showed anti-inflammatory effect at systemic level while their combination exhibited an enhanced anti-inflammatory effect in the myocardial tissue. Therefore, the findings in the current study argue that the combination of these two natural food substances could be beneficial in clinically relevant conditions where inflammation plays a role
    • …
    corecore