646 research outputs found
An improved background segmentation method for ghost removals
With ongoing research assessment in higher education and the introduction of master’s‐level work in initial teacher education, the growing need for teacher educators to develop research identities is discussed in relation to mentoring and support in two universities. Twelve interviews—with three teacher educators and three research mentors from each university—were carried out, in order to identify effective mentoring practices and other forms of support, as well as any barriers or problems encountered in developing a research profile. An innovative aspect of the methodological approach is that beginning researchers from the teacher education faculty in both universities undertook the interviewing and co‐authored the article. The need for an entitlement to and protection of research time is stressed, as well as a range of supportive practices within an active research culture. It is argued that this aspect of teacher educators’ professional development requires as much attention as the pedagogical aspects of their rol
Low cost propulsion systems for the developing world
Space has often been referred to as the final frontier. It is the curiosity of what lies beyond our planet that drives us to turn to the skies. This quest for knowledge and the chance of travelling to the heavens has compelled people to devote their lives to space science, innovation and analysis of our ever-expanding universe. Today the most significant impact of rocketry comes in the form of manned spaceflight. Vehicles like the Space Shuttle and Soyuz began the trend of greater commercialization of manned rocketry, enabling widespread access to space. Whilst the curiosity of what lies beyond may have propelled the development of the space tourism industry, its current operational cost is estimated as 28 million per passenger per flight. Although the vision of providing low cost space travel still exists, its application is hindered by the costs associated with current space vehicles and mission operations. Furthermore, if we are to better understand our universe and are keen on commercializing space, we would require the space tourism industry to operate in a similar fashion to the aviation industry. As most current launch vehicles rely on chemical propulsion, the level of uncertainty in the market drives their fuel costs. In order to reduce the cost per flight, we must effectively increase the load factor per flight and operate multiple flights, enabling a greater number of paying passengers. In order to provide widespread access to space there needs to be a greater emphasis on the research and development of low cost Reusable Launch Vehicles (RLV) which predominantly rely on alternative fuel technologies, thereby reducing the overall cost per flight. Although progress would be slow, we would still be able to witness a boom in space tourism. This paper proposes the use of magnetic levitation and propulsion (Maglev) within a vacuum chamber as a viable low-cost propulsion technology. It aims to prove that such a system is capable of providing adequate thrust to future space vehicles. As Maglev systems allow for horizontal take-off and landing, such a launch system could be used in conjunction with current airports worldwide. Although the inception and creation of such a system may seem expensive, the long-term fiscal costs are relatively lower than current day systems. This is primarily because such a system relies on electrical power, whose supply and generation costs are much lower than that of chemical propellants. Also, the maintenance costs associated with the Maglev track are minimal, as during take-off there is no physical contact between the track and the launch vehicle. Similar to the aviation industry, the success of future space exploration programs and space tourism relies on international cooperation and alliances. This not only ensures that no one country dominates access to space, but also nurtures healthy competition by providing a level playing field. By implementing the afore mentioned system in politically stable developing nations, we ensure employment, innovation and motivation, all achieved through an international alliance. This system would not only ensure a faster urban development within these countries, but would also bring the vision of space science and exploration to a larger global audience. This paper discusses the overall cost analysis for a vacuum operated Maglev system, the various options available for the generation of power required by such a system and how the system’s long term costs can be aligned with the aviation industry
Coherent optical implementations of the fast Fourier transform and their comparison to the optical implementation of the quantum Fourier transform
Optical structures to implement the discrete Fourier transform (DFT) and fast Fourier transform (FFT) algorithms for discretely sampled data sets are considered. In particular, the decomposition of the FFT algorithm into the basic Butterfly operations is described, as this allows the algorithm to be fully implemented by the successive coherent addition and subtraction of two wavefronts (the subtraction being performed after one has been appropriately phase shifted), so facilitating a simple and robust hardware implementation based on waveguided hybrid devices as employed in coherent optical detection modules. Further, a comparison is made to the optical structures proposed for the optical implementation of the quantum Fourier transform and they are shown to be very similar
Recommended from our members
Mitigating orbital debris in LEO with high power pulsed laser
There is a large amount of space debris in the size range of 1 to 10 cm that is orbiting the Earth at a very high velocity which could do tremendous damage to any space mission if it were to collide. This orbital debris has been generated from collision events between objects and fragmentations of objects in Earth orbits. The problem is that the amount of space debris is increasing exponentially with every major collision in space. To limit the probability of this happening, the rate of growth of space debris in orbit is being reduced through various design techniques employed in new space missions. However, the orbital debris already in space will require to be mitigated as well because in some of the bands, such as Low Earth Orbit (LEO), the density of space debris is very high. It is posing a threat to any operational satellite in orbit and the safety of spacecraft flights LEO is rather urgent.
The technique of using high power pulsed lasers on the ground has been viewed as the most feasible method to mitigate small space junk in the LEO band. It is one of the most viable solutions to mitigate the existing space debris in LEO. However, in order to design an effective orbital debris removal technique, the first logical step would be to gather as much information as possible on space debris that is known to exist within the orbital band of interest, like the two-line element of the space debris and its materials. This will help assess the design of the laser beam system and help give a more accurate picture of this de-orbiting strategy.
The objective of this poster is to provide a summary of the developed novel techniques for this de-orbiting model. It also presents the calculation and simulation of the required power that is necessary for the laser beam in order to slow down the orbital velocity of the space debris and also reduce its perigee. Reducing the space debris altitude by the amount necessary will significantly reduce its lifetime in Earth orbit and eventually cause it to re-enter the atmosphere where it will burn up
Eco control of agro pests using imaging, modelling & natural predators
Caterpillars in their various forms: size, shape, and colour cause significant harm to crops and humans. This paper offers a solution for the detection and control of caterpillars through the use of a sustainable pest control system that does not require the application of chemical pesticides, which damage human health and destroy the naturally beneficial insects within the environment. The proposed system is capable of controlling 80% of the population of caterpillars in less than 65 days by deploying a controlled number of larval parasitoid wasps (Cotesia Flavipes, Cameron) into the crop environment. This is made possible by using a continuous time model of the interaction between the caterpillar and the Cotesia Flavipes (Cameron) wasps using a set of simultaneous, non-linear, ordinary differential equations incorporating natural death rates based on the Weibull probability distribution function. A negative binomial distribution is used to model the efficiency and the probability that the wasp will find and parasitize a host larva. The caterpillar is presented in all its life-cycle stages of: egg, larva, pupa and adult and the Cotesia Flavipes (Cameron) wasp is present as an adult larval parasitoid. Biological control modelling is used to estimate the quantity of the Cotesia Flavipes (Cameron) wasps that should be introduced into the caterpillar infested environment to suppress its population density to an economically acceptable level within a prescribed number of days.
Keywords
Recommended from our members
LEO space debris mitigation using laser ablation
Since the first spacecraft was launched in 1957 a great number of spacecraft have been put into orbit and a significant fraction of these are still orbiting the Earth as inert vehicles or space debris. Major collision events between large satellites in Earth orbits have broken-up spacecraft systems for about half century; this has created a massive quantity of space junk – most of which are small particles. The number and quantity of debris items is increasing and as a result the probability of catastrophic collisions is growing progressively.
Objects in space, whatever their size, are potentially hazardous and can cause considerable damage, which may disable a space system and producing numerous secondary fragments as a result. Low Earth Orbit (LEO) requires particular attention because this band contains large masses of material orbiting at high relative velocities, up to 14 km/s. At this hypervelocity, even small debris, 5-10 cm, can produce extensive damage to any operation satellite and destroy any small satellites. Collision with smaller debris, 1-5 cm, could disable any space system. Therefore, our space assets in LEO are threatened by this large quantity of space junk, which may lead to collision cascading in the future.
Small orbital debris stays in LEO for a very long time (100s years) before re-entering the atmosphere, so it poses a great threat to any operational spacecraft. However, the debris lifetime can be reduced significantly by slowing the debris velocity slightly and lowering its perigee. This can be achieved by using the unique property of laser propulsion to generate thrust remotely on the orbital debris by beaming the necessary power from the ground. So, this paper assesses and simulates the engagement of laser beam pulses with space debris. It also calculates and simulates the required time and number of interactions for de-orbit and also simulates the required change in orbital velocity (∆V) of the debris to lower its altitude and cause it to change orbit and eventually fall into the upper atmosphere, where it will burn up.
In conclusion, space debris mitigation is now essential to protect existing space systems and maintain the sustainable use of outer space. That is why the space debris problem is now a very significant environmental issue. As this technique does not require launching space vehicles, we believe that this clearing strategy is an achievable and cost effective method to deflect and mitigate the effect of space debris
PHACT: parallel HOG and correlation tracking
Histogram of Oriented Gradients (HOG) based methods for the detection of humans have become one of the most reliable methods of detecting pedestrians with a single passive imaging camera. However, they are not 100 percent reliable. This paper presents an improved tracker for the monitoring of pedestrians within images. The Parallel HOG and Correlation Tracking (PHACT) algorithm utilises self learning to overcome the drifting problem. A detection algorithm that utilises HOG features runs in parallel to an adaptive and stateful correlator. The combination of both acting in a cascade provides a much more robust tracker than the two components separately could produce. © (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only
A Global Space Policy that would revive Space Exploration
Almost every nation today relies on space-based technology for communications, weather forecasting, satellite navigation and resource management, either through ndigenous
programs or through programs run by its allies. As such, it is safe to say that every country is a space-faring nation. However,when it comes to space science and technology, attention must be directed towards countries that possess the ability to launch payloads. Russia, Japan, China, ESA, India, Israel, Iran and the United States form an exclusive club of nations that not only possess launch capability but also dominate research and development in space sciences. With the exception of the ESA, whose space policy is dictated by its member states and primarily serves the EU, all other countries have national space programs governed by a dedicated space policy. However, all states including the EU have the following objectives in common:
1. Development and exploitation of space applications to serve the state’s public policy objectives,
2. Ensuring that the state’s national security and defense
needs are met with regards to space,
3. Securing unrestricted access to critical technologies allowing states to pursue independent applications, and
4. To further international collaboration between likeminded
nations through improved coordination of international activities and by setting in place a better mechanism for sharing of resources.
Whilst the above nations agree in principal to the UN Outer
Space Treaty, and they all consider space as a vital resource for ensuring national security. As such, any application or development of critical technologies is used primarily to bolster a state’s national defense capability. Current national space programs run by these countries cover various commercial, civilian and military aspects. This cross discipline research and development has led to an extremely integrated industrial base, where drawing a line between civilian and military programs is often impossible. This hazy line has often hindered technology transfer even in commercial applications as companies grapple with stringent export control regulations. With respect to the United States, whilst ITAR has ensured that critical technology is not transferred without the states consent, many in Washington agree that the regulation fails to meet its objectives and must be overhauled. It has also hindered US companies wanting to sell their products outside the United States, prompting other nations to develop indigenous technologies and market them as ITARfree.
Although it is safe to assume that research and development with regards to space will be dominated by the United States and its partners in Europe for the foreseeable future, the recent recession has caused financial strains on both sides of the Atlantic causing drastic changes with regards to space budgets and the future outlook for both NASA and ESA. This paper briefly discusses why emerging nations might consider investing in a national space program, and factors that would determine its success. It also focuses on how the establishment of a global space program could prove to be an innovative and cost-effective way of ensuring a robust space industry that serves the social and political objectives of member nations whilst promoting a global technological base that fosters innovation, growth and sustainable development
An enquiry into potential graduate entrepreneurship:is higher education turning off the pipeline of graduate entrepreneurs?
Purpose: In today’s global economy, high in talent but low in growth, the capability and skills mismatch between the output of universities and the demands of business has escalated to a worrying extent for graduates. Increasingly, university students are considering alternatives to a lifetime of employment, including their own start-up, and becoming an entrepreneur. The literature indicates a significant disconnect between the role and value of education and healthy enterprising economies, with many less-educated economies growing faster than more knowledgeable ones. Moreover, theory concerning the entrepreneurial pipeline and entrepreneurial ecosystems is applied to graduate entrepreneurial intentions and aspirations. Design/methodology/approach: Using on a large-scale online quantitative survey, this study explores graduate ‘entrepreneurial intention’ in the UK and France, taking into consideration personal, social and situational factors. The results point to a number of factors that contribute to entrepreneurial intention including social background, parental occupation, gender, subject of study, and nationality. The study furthers the understanding of and contributes to the extant literature on graduate entrepreneurship. It provides an original insight into a topical and contemporary issue, raising a number of research questions for future study.Findings: For too long, students have been educated to be employees, not entrepreneurs. The study points strongly to the fact that today’s students have both willingness and intention to become entrepreneurs. However, the range of pedagogical and curriculum content does not correspond with the ambition of those who wish to develop entrepreneurial skills. There is an urgent need for directors of higher education and pedagogues to rethink their education offer in order to create a generation of entrepreneurs for tomorrow’s business world. The challenge will be to integrate two key considerations: how to create a business idea and how to make it happen practically and theoretically. Clearly, change in the education product will necessitate change in the HE business model.Research limitations/implications: The data set collected was extensive (c3500), with a focus on France and the UK. More business, engineering and technology students completed the survey than others. Further research is being undertaken to look at other countries (and continents) to test the value of extrapolation of findings. Initial results parallel those described in this paper.Practical implications: Some things can be taught, others need nurturing. Entrepreneurship involves a complex set of processes which engender individual development, and are highly personalised. Higher Education Enterprise and Teaching and Learning Strategies need to be cognisant of this, and to develop innovative and appropriate curricula, including assessment, which reflects the importance of the process as much as that of the destination.Originality/value: This work builds on an extensive literature review coupled with original primary research. The authors originate from a variety of backgrounds and disciplines, and the result is a very challenging set of thoughts, comments and suggestions that are relevant to all higher education institutions, at policy, strategy and operational levels
Automatic plant pest detection and recognition using k-means clustering algorithm and correspondence filters
Plant pest recognition and detection is vital for food security, quality of life and a stable agricultural economy. This research demonstrates the combination of the k-means clustering algorithm and the correspondence filter to achieve pest detection and recognition. The detection of the dataset is achieved by partitioning the data space into Voronoi cells, which tends to find clusters of comparable spatial extents, thereby separating the objects (pests) from the background (pest habitat). The detection is established by extracting the variant distinctive attributes between the pest and its habitat (leaf, stem) and using the correspondence filter to identify the plant pests to obtain correlation peak values for different datasets. This work further establishes that the recognition probability from the pest image is directly proportional to the height of the output signal and inversely proportional to the viewing angles, which further confirmed that the recognition of plant pests is a function of their position and viewing angle. It is encouraging to note that the correspondence filter can achieve rotational invariance of pests up to angles of 360 degrees, which proves the effectiveness of the algorithm for the detection and recognition of plant pests
- …
