738 research outputs found
Studying Human-Centered IT Innovation Using a Grounded Action Learning Approach
This paper describes how two research methodologies, grounded theory and action learning, were combined to produce a rigorous yet creative and flexible method for field study of a recent IT-based innovation, virtual teams. Essentially, an action learning program was used to train facilitators of virtual teams and generate research data while grounded theory techniques were used to analyze and interpret the data. This paper shows how this combined method can be used to develop local and practical theory for complex, human-centered areas of information technology. The implications of this grounded action learning approach for practice and research in IS will be discussed
Structural Characteristics of Carbon Nanofibers for On-chip Interconnect Applications
In this letter, we compare the structures of plasma-enhanced chemical vapor deposition of Ni-catalyzed and Pd-catalyzed carbon nanofibers (CNFs) synthesized for on-chip interconnect applications with scanning transmission electron microscopy (STEM). The Ni-catalyzed CNF has a conventional fiberlike structure and many graphitic layers that are almost parallel to the substrate at the CNF base. In contrast, the Pd-catalyzed CNF has a multiwall nanotubelike structure on the sidewall spanning the entire CNF. The microstructure observed in the Pd-catalyzed fibers at the CNF-metal interface has the potential to lower contact resistance significantly, as our electrical measurements using current-sensing atomic force microscopy indicate. A structural model is presented based on STEM image analysis
Modeling and Dynamic performance of Energy Storage -Rotary Series Elastic Actuator for Lumbar Support Exoskeleton
The assistive exoskeletons are rapidly being developed to collaborate with humans, and the demand for the safety of human-robot interaction has become more crucial. Series elastic actuators (SEAs) have recently been developed in various fields for a variety of possible advantages, such as providing a safe human-robot interaction, reducing the impacts’ effects, and increasing energy efficiency. However, achieving the good dynamic performances of SEAs is still challenging, especially fulfilling the high bandwidth with good compliance. In this rapidly growing research field, the actuation system involving the storage device combined with the rotary series elastic actuator (ES-RSEA) is being investigated to exploit the biomechanical energy while maintaining compliance features. In this article, the modeling and control design of the energy storage rotary series elastic actuator (ES-RSEA) for the lumbar support exoskeleton is proposed, and its dynamic performances are analyzed. The ES-RSEA was designed based on storing the kinetic energy during the lifting tasks and generating assistive torque while maintaining excellent compliant characteristics. The dynamic performances and characteristics of ES-RSEA are presented in terms of force sensitivity, level of compliance, transmission ratio, and bandwidth. Simulation studies indicate that the actuator can provide excellent dynamic performance through its high bandwidth (12.44 Hz) and high force sensitivity. At the same time, it shows excellent compliance and good torque transmissibility in the low-frequency range. A PID controller can achieve high torque tracking performance and good dynamic response with a root-mean-square (RMS) error of 0.1 N.m. This article demonstrates the excellent performance and characteristics of ES-RSEA to guarantee compliance and high response to prevent injury of undesired human movements
A Circular Economy Framework based on Organic Wastes Upcycling for Biodiesel Production from Hermetia illucens
The present waste management practices have adverse environmental impacts at the same time costly. Approximately, 80 % of the Malaysian municipal wastes including organic wastes are usual disposed into landfills. Hence, transformation organic wastes not only providing economic and environmental benefits but has given waste a value. This study focused on synthesis of biodiesel from H. illucens pre-pupae fed with fruit waste and food waste. The objective was to evaluate interactions between the variables including catalyst loading, reaction time versus fatty acid methyl esters (FAME) yield (wt %), temperature and methanol to sample mass ratio. The response surface methodology (RSM) was used to investigate the bioconversion optimization process. Optimal biodiesel yield based on fruit waste achieved was 96.15 % at 51ºC; 8.3:1 methanol: mass ratio; 253 min and 15.1 % catalyst. Furthermore, the optimal yield obtained from the second set of optimization using lipids of pre-pupae derived from food waste was achieved at 94.63 %. The optimum conditions for reaction temperature was 71°C, with methanol to mass ratio of 6.8:1, at reaction time of 254 min and catalyst loading of 7.0 v/v%. The properties of FAME produced were in accordance with EN 14214 and ASTM 6751 biodiesel standards
Updating a road network dataset exploiting the results of semantic segmentation techniques applied to street-level imagery
Interleavers and BCH codes for coherent DQPSK systems with laser phase noise
The relatively high phase noise of coherent optical systems poses unique challenges for forward error correction (FEC). In this letter, we propose a novel semianalytical method for selecting combinations of interleaver lengths and binary Bose-Chaudhuri-Hocquenghem (BCH) codes that meet a target post-FEC bit error rate (BER). Our method requires only short pre-FEC simulations, based on which we design interleavers and codes analytically. It is applicable to pre-FEC BER ∼10-3, and any post-FEC BER. In addition, we show that there is a tradeoff between code overhead and interleaver delay. Finally, for a target of 10-5, numerical simulations show that interleaver-code combinations selected using our method have post-FEC BER around 2× target. The target BER is achieved with 0.1 dB extra signal-to-noise ratio
Dimensioning BCH codes for coherent DQPSK systems with laser phase noise and cycle slips
Forward error correction (FEC) plays a vital role in coherent optical systems employing multi-level modulation. However, much of coding theory assumes that additive white Gaussian noise (AWGN) is dominant, whereas coherent optical systems have significant phase noise (PN) in addition to AWGN. This changes the error statistics and impacts FEC performance. In this paper, we propose a novel semianalytical method for dimensioning binary Bose-Chaudhuri-Hocquenghem (BCH) codes for systems with PN. Our method involves extracting statistics from pre-FEC bit error rate (BER) simulations. We use these statistics to parameterize a bivariate binomial model that describes the distribution of bit errors. In this way, we relate pre-FEC statistics to post-FEC BER and BCH codes. Our method is applicable to pre-FEC BER around 10-3 and any post-FEC BER. Using numerical simulations, we evaluate the accuracy of our approach for a target post-FEC BER of 10-5. Codes dimensioned with our bivariate binomial model meet the target within 0.2-dB signal-to-noise ratio
Economic interventions to improve population health: a scoping study of systematic reviews.
BACKGROUND: Recognizing the close relationship between poverty and health, national program managers, policy-makers and donors are increasingly including economic interventions as part of their core strategies to improve population health. However, there is often confusion among stakeholders about the definitions and operational differences between distinct types of economic interventions and financial instruments, which can lead to important differences in interpretation and expectations. METHODS: We conducted a scoping study to define and clarify concepts underlying key economic interventions - price interventions (taxes and subsidies), income transfer programs, incentive programs, livelihood support programs and health-related financial services - and map the evidence currently available from systematic reviews. RESULTS: We identified 195 systematic reviews on economic interventions published between 2005 and July 2015. Overall, there was an increase in the number of reviews published after 2010. The majority of reviews focused on price interventions, income transfer programs and incentive programs, with much less evidence available from systematic reviews on livelihood support programs and health-related financial services. We also identified a lack of evidence on: health outcomes in low income countries; unintended or perverse outcomes; implementation challenges; scalability and cost-effectiveness of economic interventions. CONCLUSIONS: We conclude that while more research is clearly needed to assess suitability and effectiveness of economic interventions in different contexts, before interventions are tested and further systematic reviews conducted, a consistent and accurate understanding of the fundamental differences in terminology and approaches is essential among researchers, public health policy makers and program planners
Knowledge of pelvic floor problems: a study of third trimester, primiparous women
INTRODUCTION AND HYPOTHESIS: Pelvic floor problems in women (urinary incontinence, faecal incontinence, uterovaginal prolapse) are common, and have an adverse effect on quality of life. We hypothesized that there is low knowledge of these problems amongst primiparous women in their third trimester of pregnancy. METHODS: We conducted a cross-sectional study in antenatal clinics of three hospitals in London, UK, from 2011 to 2013. Primiparous women aged ≥18 years and in the third trimester of pregnancy answered questions on pelvic floor problems. Knowledge scores were calculated based on the proportion of questions answered correctly. RESULTS: A total of 249 women completed the question set. The average knowledge score across all domains was low at 45 %. Scores were lowest for the less common problems of faecal incontinence (35 %) and prolapse (36 %). The score for urinary incontinence was higher at 63 %, but low when questions explored more detailed levels of knowledge (41 %). Knowledge scores were positively associated with both education to tertiary level and the use of books as the information source on pregnancy and delivery. Only 35 % of women cited antenatal classes as a source. CONCLUSIONS: Knowledge of pelvic floor problems is low amongst third-trimester, primiparous women in this London-based population. Adequate knowledge of these problems is important for women to be able to make informed choices about their antenatal care and to seek help if problems arise. The data suggest scope for health-care professionals to raise these issues early during pregnancy, and to help women access accurate sources of information
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