Echo in telephones is generally undesirable but inevitable. There are two possible sources of echo in a telephone system. The impedance mismatch in hybrids generates network (electric) echo. The acoustic coupling between loudspeaker and microphone, in hands-free telephones, produces acoustic echo. Echo cancelers are used to control these echoes. In this thesis, we analyze the Least Mean Squares (LMS), Normalized LMS (NLMS), Recursive Least Squares (RLS), and Subband NLMS (SNLMS) algorithms, and evaluate their performance as acoustic and network echo cancelers. The algorithms are compared based on their convergence rate, steady state echo return loss (ERL), and complexity of implementation. While LMS is simple, its convergence rate is dependent on the eigenvalue spread of the signal. In particular, it converges slowly with speech as input. This problem is mitigated in NLMS. The complexity of NLMS is comparable to that of LMS. The convergence rate of RLS is independent of the eigenvalue spread, and it has the fastest convergence. On the other hand, RLS is highly computation intensive. Among the four algorithms considered here, SNLMS has the least complexity of implementation, as well as the slowest rate of convergence. Switching between the NLMS and SNLMS algorithms is used to achieve fast convergence with low computational requirements. For a given computational power, it is shown that switching between algorithms can give better performance than using either of the two algorithms exclusively, especially in rooms with long reverberation times. We also discuss various implementation issues associated with an integrated echo cancellation system, such as double-talk detection, finite precision effects, nonlinear processing, and howling detection and control. The use of a second adaptive filter is proposed, to reduce near-end ambient noise. Simulation results indicate that this approach can reduce the ambient noise by about 20 dB. A configuration is presented for the real time single-chip DSP implementation of acoustic and network echo cancelers, and an interface between the echo canceler and the telephone is proposed. Finally, some results obtained from simulations and implementations of individual modules, on the TMS320C31 and ADSP 2181 processors, are reported. The real time NLMS DSP implementations provide 15 dB of echo return loss. / Master of Science

This study focuses on investigating the changes in perception among students and teachers towards plants and animals after being exposed in classroom or school environments. It also examines how students view plants and animals as pets in the classroom and how teachers consider these organisms as learning tools. These exposures to uncommon plants (Monstera species) and animals (snakes, tortoises, spiders, and fish) are through access to a unique plant and animal facility at the school. To examine the effects of experiences with plants and animals on students and teachers, a Google survey was conducted, comprising a mix of multiple-choice questions (to quantify the effects) and open-ended questions (to allow freedom of expression). This survey targeted students and teachers who had access to the plant and animal facility for at least two years. Both quantitative and qualitative data were collected to quantify the effects on a large scale and to uncover the reasons behind these effects using content analysis. The results indicated that both groups exhibited changes in attitude, although the nature of the change varied depending on the type of organisms. These findings highlight the critical role of social interaction and experiences in shifting students and teachers perceptions, reflecting a key component of the learning process as outlined in Vygotsky's theory of cognitive development. Another major finding reveals that teachers recognize the educational benefits of hands-on learning with animals, supported by Dewey's experiential learning theory, while students show a preference for animals over plants due to their more active engagement with animals. Finally, the results were discussed to elucidate the broader educational implications of integrating plants and animals into teaching and the overall perceptions of plants and animals as educational resources.

This paper addresses folding the circle in half and discussing some of over one hundred different mathematical terms and functions generated in that one fold. The simplicity of process in understanding fundamentals of mathematics by folding circles and observing what is generated is unknown because we only draw pictures of circles. Examples are given about observing and exploring relationships in the circle that are appropriate for first, second, third grade level and beyond. The traditional educational ‘parts-towhole’ approach can only be fully realized through the comprehensive frame of Whole-to-parts by folding the circle. Wholemovement of the circle is not only direct; it is the only context inclusive to progressively understanding parts within unity of the Whole.

This paper addresses folding the circle in half and discussing some of over one hundred different mathematical terms and functions generated in that one fold. The simplicity of process in understanding fundamentals of mathematics by folding circles and observing what is generated is unknown because we only draw pictures of circles. Examples are given about observing and exploring relationships in the circle that are appropriate for first, second, third grade level and beyond. The traditional educational ‘parts-towhole’ approach can only be fully realized through the comprehensive frame of Whole-to-parts by folding the circle. Wholemovement of the circle is not only direct; it is the only context inclusive to progressively understanding parts within unity of the Whole.

The wrist is a body part that can be used during repetitive movements in many work environments. There is a need to measure these movements in order to notice harmful repetitive movements in advance. There are many different ways to measure these movements, such as with the use of a depth camera. The goal of this study is to determine if this can be done with high precision compared to other technologies. In order to determine this, an application was created that used several different technologies and libraries to track and pinpoint the hand’s and forearm’s location in each frame. With these locations, together with timestamps from the frames, the angular velocity of the wrist could be calculated. The recordings were made in several different test cases with factors such as background, clothes and lighting changing in each test. In order to compare the depth cameras values, a golden standard had to be set. The depth camera’s recorded values were compared to the golden standard’s recorded values by displaying the values on a graph and by calculating the root mean squared error as well as the mean absolute error. The results indicated that a depth camera can be used to measure wrist movements relatively accurately, even with more advanced movements relative to this study. The result also showed that the depth camera had problems in some test cases. / Handleden är en kroppsdel som kan användas under repetitiva rörelser i många arbetsmiljöer. Det finns ett behov av att mäta dessa rörelser för att upptäcka skadliga repetitiva rörelser i förväg. Det finns många olika sätt att mäta dessa rörelser, till exempel med hjälp av en djupkamera. Målet med denna studie är att avgöra om detta kan göras med hög precision jämfört med andra teknologier. För att avgöra detta skapades en applikation som använder flera olika teknologier och bibliotek för att spåra och lokalisera handens och underarmens position i varje bildruta. Med hjälp av dessa positioner, tillsammans med tidsstämplar från bildrutorna, kunde vinkelhastigheten för handleden beräknas. Inspelningarna gjordes i flera olika testfall där faktorer som bakgrund, kläder och belysning ändrades i varje test. För att kunna jämföra djupkamerans värden behövdes en referensstandard fastställas. Djupkamerans inspelade värden jämfördes med referensstandardens inspelade värden genom att visa värdena på en graf och beräkna rotmedelkvadratfelet samt medelabsolutfelet. Resultaten indikerade att en djupkamera kan användas för att mäta handledsrörelser relativt noggrant, även med mer avancerade rörelser i förhållande till denna studie. Resultatet visade även att djupkameran hade problem i vissa testfall.

A lavagem das mãos é reconhecida como uma das medidas mais importantes para prevenir as Infecções Hospitalares. Este estudo teve como objetivo comparar a execução e verificar a adesão aos passos da técnica de lavagem das mãos por alunos dos 2º, 3º e 4º anos de um Curso de Graduação em Enfermagem. A amostra constituiu-se de 113 alunos que estavam cumprindo estágio em instituições de saúde do município de São Paulo. Os dados foram coletados por meio de observação direta para a qual foi utilizado um instrumento em forma de “check-list" com os passos da técnica de lavagem das mãos, conforme recomendação do Ministério da Saúde do Brasil. Os resultados foram estatisticamente trabalhados, permitindo constatar que: a) os alunos dos 2º e dos 3º anos obtiveram melhor desempenho na execução da técnica de lavagem das mãos, com diferença estatisticamente significante, quando comparados ao 4º ano nos passos da técnica: “retirou jóias", “esfregou palma com dorso", “esfregou espaços interdigitais", “esfregou polegar" e “esfregou unhas". Apenas no item “fechou a torneira com papel toalha" o 4º ano apresentou-se melhor que os 2º e 3º anos; b) a adesão aos passos da técnica de lavagem das mãos dos alunos de todos os anos do curso foi muito baixa, pois na metade dos passos que compõe a técnica, os alunos apresentaram adesão menor que 50%; c) A porcentagem de alunos que executou TODOS OS PASSOS da técnica de lavagem das mãos CORRETAMENTE foi muito baixa, apenas 8,8%. Concluiu-se que os alunos do 4º ano obtiveram o pior desempenho e adesão muito baixa em quase todos os passos da técnica de lavagem das mãos, quando comparados aos dos 2º e 3º anos / Handwashing is known as one of the most important measures in preventing hospital-acquired Infections. This study had the objective of comparing the performance and verifying the adhesion of students from the 2nd, 3rd and 4th years of the Graduation nursing course to the steps of this technique. The sample was made of 113 students who were under the internship program in health institutions in the city of Sao Paulo. The data were collected through unobtrusive observation based on an instrument in a check-list form with all the steps of the hands-washing technique, as suggested by the Brazilian Health Ministry. The results were statistically treated showing that: a) the students from the 2nd and 3rd years had better results in the execution of the handwashing technique, with a significant statistical difference, when compared to the students from the 4th year considering the steps: “jewelry-removing", “rubbed the palm of the hand with its back", "rubbed spaces between fingers", “rubbed thumb" and “rubbed nails". Considering the item “closing the faucet with a paper towel" the students from the 4th year were better than the ones from the second and third years; b) the students from all years of graduation the 2nd, 3rd and 4th years showed low adhesion to the hands-washing technique steps, once they presented the adhesion to less than 50% of the steps; c) The percentage of students who performed ALL THE STEPS of the handwashing technique CORRECTLY was very low, only 8.8%. It was concluded that the students from the 4th years in almost all had the worst performance and the lowest adhesion to the hands-washing technique when compared to the students from the 2nd and 3rd years

Speech processing in the automotive environment is a challenging problem due to the presence of powerful and unpredictable nonstationary noise. This thesis addresses two detection problems involving both nonstationary noise signals and nonstationary desired signals. Two detectors are developed: one to detect passing vehicle noise in the presence of speech and one to detect speech in the presence of passing vehicle noise. The latter is then measured against a state-of-the-art voice activity detector used in telephony. The process of compiling a library of recordings in the automobile to facilitate this research is also detailed.

The purpose of this study was to conduct a qualitative analysis of service learning. This analysis was performed to collect data on student perceptions of service learning and to understand the importance of service learning on community college students in their own words. Data were collected through interviews with 24 community college participants from Virginia Highlands Community College and Mountain Empire Community College, both in Southwest Virginia. I used a nonstandard interview because it is less abrupt, remote and arbitrary than the structured interview. I wanted to tap into the experiences of these students to learn what they thought, how they felt, and how service learning benefited or did not benefit them. Permission to conduct this study was granted by the Institutional Review Board. Personal contact was made with school officials. Interviews were conducted in phases depending upon the availability and convenience of the participant. Findings showed that students involved in service learning experience many outcomes. These ranged from hands-on experience, social benefits, academic benefits especially in the area of accounting, civic responsibility, personal efficacy, civic mindedness and community building, developing a meaningful philosophy on life, appreciation for diversity, altruism and student autonomy. Findings did show that time and family or job responsibilities seemed to be the reason more students do not get involved. Students were concerned about the lack of enthusiasm from the instructors. They also said there would be more student participation if lab time, like a biology or science lab, were built into the service hours.

Hands convey important social information, such as an individual’s emotions, goals, and desires, are used to direct attention through pointing, and are a major organ for haptic perception. However, very little is known about infants’ representation of human hands. In Experiment 1, infants tested in a familiarization/novelty preference task discriminated between images of intact hands and images that contained first-order structure distortions (i.e., with locations of fingers altered to result in an unnatural configuration). In Experiment 2, infants tested in a spontaneous preference task exhibited a preference for scrambled hand images over intact images, indicating that 3.5-month-olds have gained sufficient sensitivity to the configural properties of hands to discriminate between intact versus scrambled images without any training in the laboratory. In both procedures, infants’ performance was disrupted by the inversion of images, suggesting that infants’ performance in upright conditions was not based on low-level features. These results indicate that sensitivity to the structure of hands develops early in life. This may lay the foundation for the development of the functional use of hand information for social communication.

<p>This thesis examines learner-centered animal science education and its relationships with emotion, motivation and performance. Part I focuses on active learning strategies implemented in an introductory animal sciences course. This large-enrollment course had traditionally been taught through traditional, passive learning methods. Instructors added learning activities such as case studies and hands-on laboratory stations to supplement lecture-based instruction. Chapter Two summarizes the impacts of different active learning techniques implemented in the course and characterizes students enrolled in the course based on their interests, past experiences, and demographic information. Building on these findings, Chapter Three describes an experiment quantitatively comparing the effects of three learning strategies (lecture, case study, and laboratory station) on students’ experience of interest and motivation. In both studies, students rated themselves highly interested in animal sciences throughout the semester. More collaborative, problem-based instructional methods (i.e. laboratory stations and case studies) were favored by students and resulted in higher student interest and internalized motivation. Results presented in Part I may inform the creation of instructional techniques to support student motivation, retention, and performance. Part II describes an online learning program contextualizing STEM learning within poultry science and implemented in high school classrooms during the fall 2018 semester. The program was designed to increase students’ knowledge and interest in both poultry and STEM fields to support the development of poultry- and STEM-literacy and meet workforce needs. Chapter Four describes program effects on students’ knowledge, awareness, and interest in the poultry industry. In contrast, Chapter Five focuses on the program’s effects on students’ STEM learning and STEM motivation. In addition, Chapter Five provides background on teacher and contextual factors influencing the program’s implementation. Results from these studies indicate that the program effectively increased students’ STEM and poultry knowledge, and increased motivation for some students. However, other qualitative and quantitative data indicated that some students experienced difficulties relating content to their lives. In addition, the program’s effects on students differed substantially based on teachers and classroom implementation. Both students and teachers also mentioned a need for more hands-on, collaborative elements in the program. Although results from Part II show promise that contextualizing STEM learning within agriculture may effectively increase knowledge and motivation, more research is needed to understand how to select and personalize contexts to maximize their relevance to students, and how to support teachers in effectively implementing these approaches. In conclusion, learner-centered instructional strategies such as problem-based and hands-on learning can be designed to enhance students’ interest, motivation, and performance. However, more research is needed to understand the complex personal and contextual factors moderating the effectiveness of these approaches when implemented in authentic classroom settings. Future studies clarifying these effects can advance the development of theory-based educational resources.</p>