• 已选条件:
 全选  【符合条件的数据共:2204028条】

2106年

Manana, Ditebogo Bornephilia

瑞士 | 英文

预览  |  原文链接  |  全文  [ 浏览:7 下载:13  ]     分享

The levels of crime and violence in South Africa are at a very alarming and concerning rate. It is against this background that, this situation is treated as a matter of urgency by the South African presidency, government departments, civil society organisations and business sector to prevent and decreace the possibility of ruined socio-economic development in South Africa.Heedful to the status quo of the South African crime levels, the implementing of the integrated social crime prevention strategy was approved by the Sourth African presidency as a comprehensive and an appropriate framework to deal with the high levels of crime and to create opportunities for safety in South Africa (Presidency, 2010).The goal of this study was to explore the inherent approaches to implementing the integrated social crime prevention strategy in South Africa. In exploring this goal and objectives of the study, the researcher used Tech’s (in Creswell, 1994) data analysis framework to identify appropriate approaches to implementing the integrated social crime prevention strategy in South Africa.The findings in the study have shown that alternative approaches are crititical to implementing the integrated social crime prevention stategy in South Africa to foster integrated and collaborative delivery of services by all government department, civil society otganisation and private sector. It is also evident that, the recommendations of this study can be used as a guideline by different sectors to improve the implementation of the strategy in South Africa.The following are the key words used throughout the study: approach, implementation, integrated, social crime prevention and strategy which answered the primary research question: What are the inherent approaches to implementing the integrated social crime prevention strategy in South Africa. These words are defined in chaper one (1).

    2023年

    Ojelabi, Adedotun O., Flint

    瑞士 | 英文

    预览  |  原文链接  |  全文  [ 浏览:2 下载:3  ]     分享

    Pokémon Go arguably depicts the most popular adoption of augmented reality (AR) technology on any platform and particularly mobile games during the conduct of this research. The mobile location-based game was launched in July 2016, to the delight of millions of people globally. Pokémon Go requires people to physically navigate the real world in the course of playing the game; this was a relatively new experience for many especially as a mobile game. The need to physically navigate the real world in Pokémon Go prompted the quest to examine what impacts Pokémon Go has on college students. Specifically, we focus on the impact on their social interaction and physical activity as there were studies that have shown that traditional mobile games and video games have made people become anti-social, adopt sedentary lifestyles resulting in various issues in social and health aspects. This research aims to acquire a better understanding of how AR games like Pokémon Go impacts social interaction and physical activity, and to recommend guidelines for developing similar augmented reality games to promote social interaction and physical activity. Semi-structured interviews were conducted with twenty participants attending a college in the mid-western region of the United States of America. Our findings revealed that Pokémon Go encouraged increased social interaction among family, friends and strangers. Participants also enjoyed some health and educational benefits as a result of playing Pokémon Go. We also identified some challenges and concerns of playing Pokémon Go which borders on personal safety and security, circumvention of game design as well as privacy. Our findings led us to propose recommendation for augmented reality game design that will promote social interaction and physical activity. These include incorporating social game components to enhance players’ overall gaming experience, addressing game design circumvention by developing algorithms that will intelligently permit cheating or out rightly prevent cheating. We also recommended a more transparent and flexible permission requests to address privacy concerns.

      2020年

      Todd, Kristina, Shurtz, Teresa, Espinosa, Nicolas J, Hostetler, John M

      美国 | 英文

      预览  |  原文链接  |  全文  [ 浏览:0 下载:0  ]     分享

      2020年

      Beck, Robin, Songer, Jarvis, Szalai, Christine, Saunders, David

      美国 | 英文

      预览  |  原文链接  |  全文  [ 浏览:0 下载:0  ]     分享

      The InSight spacecraft was proposed to be a build-to-print copy of the Phoenix vehicle due to the knowledge that the lander payload would be similar and the trajectory would be similar. However, the InSight aerothermal analysts, based on tests performed in CO2 during the Mars Science Laboratory mission (MSL) and completion of Russian databases, considered radiative heat flux to the aftbody from the wake for the first time for a US Mars mission. The combined convective and radiative heat flux was used to determine if the as-flown Phoenix thermal protection system (TPS) design would be sufficient for InSight. All analyses showed that the design would be adequate. Once the InSight lander was successfully delivered to Mars on November 26, 2018, work began to reconstruct the atmosphere and trajectory in order to evaluate the aerothermal environments that were actually encountered by the spacecraft and to compare them to the design environments.The best estimated trajectory (BET) reconstructed for the InSight atmospheric entry fell between the two trajectories considered for the design, when looking at the velocity versus altitude values. The maximum heat rate design trajectory (MHR) flew at a higher velocity and the maximum heat load design trajectory (MHL) flew at a lower velocity than the BET. For TPS sizing, the MHL trajectory drove the design. Reconstruction has shown that the BET flew for a shorter time than either of the design environments, hence total heat load on the vehicle should have been less than used in design. Utilizing the BET, both DPLR and LAURA were first run to analyze the convective heating on the vehicle with no angle of attack. Both codes were run with axisymmetric, laminar flow in radiative equilibrium and vibrational non-equilibrium with a surface emissivity of 0.8. Eight species Mitcheltree chemistry was assumed with CO2, CO, N2, O2, NO, C, N, and O. Both codes agreed within 1% on the forebody and had the expected differences on the aftbody. The NEQAIR and HARA codes were used to analyze the radiative heating on the vehicle using full spherical ray-tracing. The codes agreed within 5% on most aftbody points of interest.The LAURA code was then used to evaluate the conditions at angle of attack at the peak heating and peak pressure times. Boundary layer properties were investigated to confirm that the flow over the forebody was laminar for the flight.Comparisons of the aerothermal heating determined for the reconstructed trajectory to the design trajectories showed that the as-flown conditions were less severe than design

        2020年

        Jhabvala, M, Choi, K, Gunapala, S, Razehi, M, Sundaram, M

        美国 | 英文

        预览  |  原文链接  |  全文  [ 浏览:0 下载:0  ]     分享

        In 1988 DARPA provided funding to NASA’s Goddard Space Flight Center to support the development of GaAs Quantum Well Infrared Photodetectors (QWIP). The goal was to make a single element photodetector that might be expandable to a two-dimensional array format. Ultimately, this led to the development of a 128 x 128 element array in collaboration with AT&T Bell Labs and Rockwell Science Center in 1990. We continued to develop numerous generations of QWIP arrays most recently resulting in the multi-QWIP focal plane for the NASA-US Geological Survey (USGS) Landsat 8 mission launched in 2013 and a similar instrument on the Landsat 9 mission to be launched in 2020. Toward the end of the Landsat 8 QWIP-based Thermal Infrared Sensor (TIRS) instrument the potential of the newly developed Strained Layer Superlattice (SLS) detector array technology became of great interest to NASA for three primary reasons: 1) higher operating temperature; 2) broad spectral response and; 3) higher sensitivity. We have collaborated extensively with QmagiQ, LLC and Northwestern University to further pursue and advance the SLS technology ever since we started back in 2012. In December of 2018 we launched the first SLS-based IR camera system to the International Space Station on board the Robotic Refueling Mission #3 (RRM3). This paper will describe the evolution of QWIP technology leading to the current development of SLS-based imaging systems at the Goddard Space Flight Center over the past 30 years.

          2020年

          Petro, Susanna, Pham, Karen, Hilton, George

          美国 | 英文

          预览  |  原文链接  |  全文  [ 浏览:0 下载:0  ]     分享

          This paper describes the plans, flows, key facilities, components and equipment necessary to fully integrate, functionally test and qualify the Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) Observatory. PACE is currently in the design phase of mission implementation. It is scheduled to launch in 2022, extending and improving NASA's twenty-year record of satellite observations of global ocean biology, aerosols and clouds. PACE will advance the assessment of ocean health by measuring the distribution of phytoplankton, which are small plants and algae that sustain the marine food web. It will also continue systematic records of key atmospheric variables associated with air quality and the Earth's climate. The PACE observatory is comprised of the spacecraft and three instruments, an Ocean Color Instrument (OCI) and two polarimeters, the Hyper-Angular Rainbow Polarimeter 2 (HARP2) and the Spectro-Polarimeter for Exploration (SPEXone). The spacecraft and the OCI, which is the primary instrument, are developed and integrated at the NASA Goddard Space Flight Center (GSFC). The OCI is a hyper-spectral scanning (HSS) radiometer designed to measure spectral radiances from the ultraviolet to shortwave infrared (SWIR) to enable advanced ocean color and heritage cloud and aerosol particle science. The HARP2 and SPEXone are secondary instruments on the PACE observatory, acquired outside of GSFC. The Hyper-Angular Rainbow Polarimeter instrument (HARP2) is a wide swath imaging polarimeter that is capable of characterizing atmospheric aerosols for purposes of sensor atmospheric correction as well as atmospheric science. The SPEXone provides atmospheric aerosol and cloud data at high temporal and spatial resolution. This paper will focus on the Integration and Test (I&T) activities for the PACE mission at NASA GSFC. This I&T phase consists of mechanical, electrical and thermal integration and test of all the spacecraft subsystems and the integration of the instruments with the spacecraft. The PACE observatory environmental tests include electromagnetic interference (EMI)/electromagnetic compatibility (EMC), vibration, acoustics, shock, thermal balance, thermal vacuum, mass properties and center of gravity. This paper will also discuss the observatory shipment to the launch site as well as the launch site processing.