235 research outputs found
Adaptive, differential pulse-code modulation for speech processing
The objective of the research reported here is the design of efficient speech coders that can easily be implemented in integrated circuit hardware. Companding techniques like those introduced by M. R. Winkler, J. A. Greefkes, F. DeJager, A. Tomozawa and H. Kaneko were explored along with a large body of theory concerning the application of linear prediction to speech coding.
The best features of the speech signal to be measured and coded are the overall amplitude, the resonant frequencies and dampings of the vocal cavity and the fundamental frequency of the vocal cord oscillations. Adaptive quantization was used to track variations in overall amplitude, and adaptive prediction was used to track the frequencies and dampings of the cavity resonances. No attempt was made to exploit redundancies related to the vocal cord oscillations, however.
An adaptive differential pulse code modulator (i.e., an ADPCM coder) with a fixed integrator was simulated first. Later a hardware model was constructed, signal to noise measurements were taken and subjective tests conducted. When operating at 4 bits per sample, speech of a quality nearly equal to that of 7 bit log PCM was regenerated by the ADPCM encoder. At 3 bits per sample speech quality was nearly equal to 6 bit log PCM.
Further improvements were achieved with the application of adaptive predictors in place of the integrator. The predictor coefficients form a vector which is adapted in a direction away from the gradient with respect to the error power. By applying this technique to the quantized signals occurring in the coder, the coefficients are derived from the quantized error signal; hence, there is no need to transmit them
Meta-Network Analysis of Complex Construction Systems: Improving Project Efficiency Using Novel Computer-Based Analytic Methodology
The objective of this study is to build upon the framework of a meta-network approach to assessing vulnerabilities in construction projects. By viewing these complex environments as configurations of various nodes and links, it is possible to show the relationship between each entity in the project and the overall completion that is achieved from these connections. To expand upon previous studies, the vulnerabilities measured from this approach will be used to optimize the current network to eliminate any shortcoming in the project model. By investigating the congruence of different agents on the project, resources and informational nodes can be supplied through different project simulations to increase project completion by eliminating any potential vulnerabilities. The application of this optimization is shown through a case study related to an excavation project of the University of Connecticut’s Athletic District Development Project. This framework is applied to the dynamic interactions of this study and used to reduce any uncertainty that stems from inefficient resource distribution throughout the project. The application of this optimization model creates a useful tool for the construction management industry to plan projects and eliminate potential errors in scheduling and resource distribution from the earliest stages of a project’s life cycle
Characterization and evaluation of head impact sensors and varsity football helmets
An increased understanding of the effects of brain injury in recent years has led to greater attention being given to the topic. A desire to investigate the causal agents of these injuries in athletes has led to the development and use of several devices that track head impacts as well as improving helmet technology to protect players from said impacts. In order to determine which devices are able to best measure head impacts, a Hybrid III headform was used to quantify the accuracy for translational and angular accelerations. Testing was performed by means of administering impacts to a helmet on the headform, with each device mounted according to manufacturer instruction, using an impulse hammer. For peak translational acceleration, the worst locational root-mean-square error for a head mounted device was 74.68% while the worst for a helmet mounted device was 297.62%. Head mounted devices outperformed those mounted in helmets and should be the basis of future sensor designs. For the sake of determining the effectiveness of recent helmet innovations, several helmet models were fastened to the headform in order to measure the response accelerations from impacts. The impulse hammer provided transient force data which allowed for the comparison of the input blow and output accelerations for each impact, and several metrics were determined and evaluated to determine helmet impact mitigation ability. Relative helmet effectiveness between models varied by region. The lowest peak translational acceleration metric was 0.31, and the highest was 0.57. The corresponding angular acceleration metric had a low of 0.23 and a high above one at 1.71. The helmets evaluated were more consistent in mitigating peak translational acceleration than peak angular acceleration
Screening for heart disease in athletes
Physical activity, be it regular exercise or sports at whatever level, should be beneficial and not deleterious. Hence, it is important that the medical profession is aware that cardiovascular related deaths are the leading cause of mortality in athletes during sports. In 2009 the International Olympic Committee issued a consensus statement on the periodic health evaluation of elite athletes. This includes ‘a comprehensive assessment of the athlete’s current health status and risk of future injury or disease and, typically, is the entry point for medical care of the athlete’. Although this consensus statement targeted elite athletes, the periodic health evaluation design is simple enough that it could easily be extrapolated for use for all physically active individuals. The periodic health evaluation’s role is to screen for musculoskeletal or medical conditions that may place an athlete at risk for safe participation. Since this statement was issued, numerous international sport organisations have recommended a screening programme for individuals who partake in regular physical activity. Stress is made on the importance of a thorough health and family history with an emphasis on cardiovascular issues. There is no international consensus on the use of an electrocardiogram (ECG) as part of a screening programme; however most international sports federations and the European Cardiac and Sports Medicine societies strongly recommend it. What there is agreement on is that the doctor that reads an ECG should be knowledgeable of the physiological adaptations of the athletic heart that could lead to errant, yet perfectly safe, ECG traces.peer-reviewe
Process Information and Creative Mindsets: An Examination of Their Role in the Evaluation of Creativity
Evaluating creativity is a key role for any organization interested in innovation and how that evaluation occurs has been a focal point of researchers. Although creativity scholars have made strides in understanding creativity evaluations, questions remain about the role that process information plays in the evaluation. While most creativity research involves some type of outcome, such as an idea or product, the evaluators often have no description of the creator’s work process or any understanding of the idea or product’s creation. In this dissertation, I build upon the existing evaluation literature and critically examine how process information may influence the evaluation of an outcome’s creativity. In doing so, I investigate narratives of both iteration and insight process information, both of which are representative of creative work and likely to influence an evaluator’s perception. I validated materials to manipulate the narratives of creative process information and conducted an experimental study to determine how they affected perceptions of creativity. In doing so, I also considered the role of an evaluator’s growth creative mindset and how evaluators may differentially interpret and perceive the process information and final product depending on their mindset. The results offer some support that an evaluator’s growth creative mindset matters for creativity evaluations, but the findings do not support the interaction effect hypotheses between an evaluator’s growth creative mindset and process information on a product’s perceived creativity. Post-hoc analyses suggest that the effects of growth creative mindset occur predominantly via the utility of the product, while not affecting the perceived novelty. Post-hoc analyses also found a significantly negative effect of iteration process information on a product’s perceived utility. This dissertation has implications for any creators who need to discuss or describe their work to potential evaluators like colleagues or managers, as well as for researchers interested in understanding more about the multi-faceted nature of creative evaluations. The implications of this work also has the potential to increase in relevance as work from home policies and organizational norms change in a Post-Pandemic world where individuals have more autonomy and control about what others see and know abouttheir work process
Placing Global Science in Africa: International Networks, Local Places, and Virus Research in Uganda, 1936-2000
“Placing Global Science in Africa: International Networks, Local Places, and Virus Research in Uganda, 1936-2000” analyzes six decades in the history of the Uganda Virus Research Institute (UVRI) as a site of knowledge production in order to show the connections between place, scientific research, and the history of Uganda and nearby parts of East Africa. It repositions Africans and African institutions at the core of the narrative, re-centering our understanding of the relationship between global science and African science.
Using archival sources, published articles, and over sixty oral history interviews collected during fifteen months of field work, it explores the events that led to the establishment of Africa, and Uganda in particular, as a center of biomedical research, much of it focused on HIV/AIDS. It adds a historical dimension to a body of literature on medical research in Africa that has been dominated by anthropologists and shows how Uganda was a hub of virus research long before the AIDS epidemic. The project takes advantage of the longevity of the UVRI (previously known as the Yellow Fever Research Institute or YFRI and the East African Virus Research Institute or EAVRI) to study the changes and continuities in research practices between colonial, post-colonial, and post-Civil War periods of Ugandan history and to trace changing ideas about the relationship between disease, health, and place; the role of African skilled labor; the place of African institutions in the global community; and the ways African natural and social environments are investigated and represented for different audiences. All of this material serves to refine our understanding of what the “local” of local partnerships in international medical research collaborations signifies and how it shapes major international medical research projects
Normalisation method can affect gluteus medius electromyography results during weight bearing exercises in people with hip osteoarthritis (OA): a case control study.
Surface electromyography (sEMG) is used to assess muscle activation during therapeutic exercise, but data are significantly affected by inter-individual variability and requires normalisation of the sEMG signal to enable comparison between individuals. The purpose of this study was to compare two normalisation methods, a maximal method (maximum voluntary isometric contraction (MVIC)) and non-maximal peak dynamic method (PDM), on gluteus medius (GMed) activation using sEMG during three weight-bearing exercises in people with hip osteoarthritis (OA) and healthy controls. Thirteen people with hip OA and 20 controls performed three exercises (Squat, Step-Up, Step-Down). Average root-mean squared EMG amplitude based on MVIC and PDM normalisation was compared between groups for both involved and uninvolved hips using Mann-Whitney tests. Using MVIC normalisation, significantly higher normalised GMed EMG amplitudes were found in the OA group during all Step-up and down exercises on the involved side (p=0.02-0.001) and most of the Step exercises on the uninvolved side (p=0.03-0.04), but not the Squat (p\u3e0.05), compared to controls. Using PDM normalisation, significant between-group differences occurred only for Ascending Squat (p=0.03) on the involved side. MVIC normalisation demonstrated higher inter-trial relative reliability (ICCs=0.78-0.99) than PDM (ICCs=0.37-0.84), but poorer absolute reliability using Standard Error of Measurement. Normalisation method can significantly affect interpretation of EMG amplitudes. Although MVIC-normalised amplitudes were more sensitive to differences between groups, there was greater variability using this method, which raises concerns regarding validity. Interpretation of EMG data is strongly influenced by the normalisation method used, and this should be considered when applying EMG results to clinical populations
Mycoplasma Pneumonia: Late Treatment Leading to Acute Respiratory Distress Syndrome and Renal Failure
Introduction: Mycoplasma pneumonia is one of the most common types of pneumonia, although it is often not diagnosed due to mild clinical course.
Aims: In this case study we aim to describe the importance of considering mycoplasma pneumonia in high-risk groups.
Methods: We present the case of a 27-year-old woman admitted with pneumonia, progressing to acute respiratory distress syndrome and acute kidney injury. She had a prolonged stay in the ICU, requiring intubation and continuous veno-venous haemofiltration (CVVH). After 1 month in hospital, she was discharged with full recovery.
Discussion: Mycoplasma pneumonia is a common type of pneumonia in the community, but only a small percentage of patients require hospitalization. Delayed treatment can result in multi-organ failure, which requires intensive care and long hospital stays
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