PRE-IMPACT FALL DETECTION USING VERTICAL ANGLE AND ACCELERATION TRIANGLE FEATURE

In this study, pre-impact fall detection algorithms were developed using an IMU sensor at the waist. Forty male volunteers participated in the experiments (four types of falls and six types of ADLs). An IMU was used to measure acceleration, angular velocity and vertical angle during all activities. Thresholds of acceleration, angular velocity, and vertical angle were set to 0.9 g, 47.3°/s, and 24.7° respectively for algorithm using vertical angle. Thresholds of acceleration, angular velocity, and triangle feature were set to 0.9 g, 47.3°/s, and 0.19 respectively for pre-impact fall detection algorithm using triagle feature. Pre-impact fall detection algorithms with the vertical angle and the triangle feature resulted in the lead time of 402 ms and 427 ms respectively. Both algorithms showed 100% accuracy to detect falls

SEARCHING BASED ON QUERY DOCUMENTS

Searches can start with query documents where search queries are formulated based on document-level descriptions. This type of searches is more common in domain-specific search environments. For example, in patent retrieval, one major search task is finding relevant information for new (query) patents, and search queries are generated from the query patents One unique characteristic of this search is that the search process can take longer and be more comprehensive, compared to general web search. As an example, to complete a single patent retrieval task, a typical user may generate 15 queries and examine more than 100 retrieved documents. In these search environments, searchers need to formulate multiple queries based on query documents that are typically complex and difficult to understand. In this work, we describe methods for automatically generating queries and diversifying search results based on query documents, which can be used for query vi suggestion and for improving the quality of retrieval results. In particular, we focus on resolving three main issues related to query document-based searches: (1) query generation, (2) query suggestion and formulation, and (3) search result diversification. Automatic query generation helps users by reducing the burden of formulating queries from query documents. Using generated queries as suggestions is investigated as a method of presenting alternative queries. Search result diversification is important in domain-specific search because of the nature of the query documents. Since query documents generally contain long complex descriptions, diverse query topics can be identified, and a range of relevant documents can be found that are related to these diverse topics. The proposed methods we study in this thesis explicitly address these three issues. To solve the query generation issue, we use binary decision trees to generate effective Boolean queries and labeling propagation to formulate more effective phrasal-concept queries. In order to diversify search results, we propose two different approaches: query-side and result-level diversification. To generate diverse queries, we identify important topics from query documents and generate queries based on the identified topics. For result-level diversification, we extract query topics from query documents, and apply state-of-the-art diversification algorithms based on the extracted topics. In addition, we devise query suggestion techniques for each query generation method. To demonstrate the effectiveness of our approach, we conduct experiments for various domain-specific search tasks, and devise appropriate evaluation measures for domain-specific search environments

Application of the transtheoretical model to identify predictors of physical activity transition in university students

Within the physical activity domain the majority of transtheoretical model research has employed a cross sectional research design. While useful for characterizing participants within the various stages of change, it fails to capture the dynamic nature of change. The purpose of the current study was to identify predictors of naturally occurring transitional shift patterns in physical activity behavior observed over six months among 202 university students. The full set of variables from the transtheoretical model as well as exercise METS was examined. Results indicated that stable active participants reported more exercise METs at baseline than both activity adopters and perpetual preparers in multinomial logistic regression analysis (p<.01). Stable active participants were also significantly different in their cognitive process of change scores compared to activity adopters (p<.05). Activity adopters differed from stable active participants in their initial decisional balance scores (p<.05). These findings should help inform theory development and physical activity interventions and programs.Dentro del dominio de la actividad física, la mayoría de la investigación de modelos transteóricos ha empleado un diseño de investigación transversal. Si bien es útil para caracterizar a los participantes en las diversas etapas del cambio, no capta la naturaleza dinámic del cambio. El propósito del presente estudio fue identificar predictores de patrones de cambio de transición que ocurren naturalmente en el comportamiento de la actividad física observados durante seis meses entre 202 estudiantes universitarios. Se examinó el conjunto completo de variables del modelo transteórico, así como el ejercicio METS. Los resultados indicaron que los participantes activos estables reportaron más MET de ejercicio al inicio que los adoptantes de actividad y los preparadores perpetuos en el análisis de regresión logística multinomial (p <0.01). Los participantes activos estables también fueron significativamente diferentes en su proceso cognitivo de puntuaciones de cambio en comparación con los adoptantes de actividad (p <0.05). Los adoptantes de actividades difirieron de los participantes activos estables en sus puntuaciones iniciales de equilibrio decisional (p <0.05). El presente estudio sugiere que los procesos cognitivos de cambio y la creación de un equilibrio decisorio positivo son factores especialmente importantes en los primeros seis meses de adopción de actividad física

Hodge ideals and spectrum of isolated hypersurface singularities

We introduce Hodge ideal spectrum for isolated hypersurface singularities to see the difference between the Hodge ideals and the microlocal $V$-filtration modulo the Jacobian ideal. Via the Tjurina subspectrum, we can compare the Hodge ideal spectrum with the Steenbrink spectrum which can be defined by the microlocal $V$-filtration. As a consequence of a formula of Mustata and Popa, these two spectra coincide in the weighted homogeneous case. We prove sufficient conditions for their coincidence and non-coincidence in some non-weighted-homogeneous cases where the defining function is semi-weighted-homogeneous or with non-degenerate Newton boundary in most cases. We also show that the convenience condition can be avoided in a formula of Zhang for the non-degenerate case, and present an example where the Hodge ideals are not weakly decreasing even modulo the Jacobian ideal.Comment: 29 page

Association of Health Risk Perception and Physical Activity among Adolescents

The current study was to identify health risk perceptions and perception bias in adolescents. Moreover, the study investigated the relationship of risk perceptions with physical activity. A total of 625 adolescents (314 male and 311 female) were voluntarily participated from the Nowon district, geographically located in northern Seoul. In order to measure health risk perceptions a Korean version of self-other risk judgments profile and leisure time exercise questionnaire were used. Results indicated that the study participants, regardless of gender and age, tend to underestimate their vulnerability to the majority of health risk events. The finding revealed that there were significant differences in perception bias toward to health risks by gender and the physical activity level. Furthermore, it is revealed that risk perceptions are directly associated with physical activity participation. The significance of this study lies in the fact that it made a unique contribution to the existing knowledge in exercise and health psychology on relationship between risk perceptions and physical activity.El presente estudio tuvo como objetivo identificar las percepciones del riesgo para la salud y el sesgo de percepción en adolescentes. Además, el estudio investigó la relación entre las percepciones de riesgo y la actividad física. De forma voluntaria, participaron un total de 625 adolescentes (314 hombres y 311 mujeres) del distrito de Nowon, geográficamente ubicado en el norte de Seúl. Con el fin de medir las percepciones de riesgo sobre la salud se utilizó una versión coreana del perfil de juicios de riesgo self-other y el cuestionario de ejercicio de tiempo libre. Los resultados indicaron que los participantes del estudio, independientemente del sexo y la edad, tienden a subestimar su vulnerabilidad a la mayoría de los. El hallazgo reveló que había diferencias significativas en el sesgo de percepción hacia los riesgos de salud por género y el nivel de actividad física. Además, se revela que las percepciones de riesgo están directamente asociadas con la participación en la actividad física. La importancia de este estudio reside en el hecho de que hizo una contribución única al conocimiento existente en el ejercicio y la psicología de la salud sobre la relación entre las percepciones de riesgo y la actividad física

Diversifying query suggestions based on query documents

Many domain-specific search tasks are initiated by document-length queries, e.g., patent invalidity search aims to find prior art related to a new (query) patent. We call this type of search Query Document Search. In this type of search, the initial query docu-ment is typically long and contains diverse aspects (or sub-topics). Users tend to issue many queries based on the initial document to retrieve relevant documents. To help users in this situation, we propose a method to suggest diverse queries that can cover multi-ple aspects of the query document. We first identify multiple que-ry aspects and then provide diverse query suggestions that are effective for retrieving relevant documents as well being related to more query aspects. In the experiments, we demonstrate that our approach is effective in comparison to previous query suggestion methods

Cultural Foundations of Contentious Democracy in South Korea

This study takes a cultural approach to examine the unstable and contentious nature of Korean democracy. Analyzing an original nationwide survey conducted in 2015, we find that the democratic and participatory culture of the Korean people underlies Korean democracy. This finding suggests substantial tension between the participatory orientation of the public and Korean representative democracy

BIOMECHANICAL CHARACTERISTICS OF THE LOWER EXTREMITY FROM GAIT INTIATION TO THE STEADY-STATE WALKING

In this study, biomechanical characteristics during the whole process of gait initiation for twenty healthy volunteers were determined by the three dimension motion analysis. Gait initiation, a transitional movement phenomenon from quiet stance to steady-state walking, involves a series of muscular activities, GRFs, movements of COP and COM and joint motions. Results showed that the location of the net COP to be most lateral during double limb stance at the beginning of gait initiation. During gait initiation, changes in anteroposterior components of GRFs were first found and then changes in vertical components followed. Hip and knee motions were found before the ankle joint motion. Walking speed, step length and stride length gradually increased until the second step. The interaction between the COM and COP is tightly regulated to control the trajectory of the COM and thereby control total body balance