The rapid growth of point-of-care polysomnographic alternatives has necessitated standardized eva... more The rapid growth of point-of-care polysomnographic alternatives has necessitated standardized evaluation and validation frameworks. The current average across participant validation methods may overestimate the agreement between wearable sleep tracker devices and polysomnography (PSG) systems because of the high base rate of sleep during the night and the interindividual difference across the sampling population. This study proposes an evaluation framework to assess the aggregating differences of the sleep architecture features and the chronologically epoch-by-epoch mismatch of the wearable sleep tracker devices and the PSG ground truth. An AASM-based sleep stage categorizing method was proposed to standardize the sleep stages scored by different types of wearable trackers. Sleep features and sleep stage architecture were extracted from the PSG and the wearable device’s hypnograms. Therefrom, a localized quantifier index was developed to characterize the local mismatch of sleep scor...
Understanding of eye movement is crucial for viewers’ behavior recognition. The movement of eyeba... more Understanding of eye movement is crucial for viewers’ behavior recognition. The movement of eyeballs in space can be described by a nonlinear differential equation that should be processed with a special identification approach due to its nonlinearities. Electrooculography (EOG) is a technique for measuring the cornea—retinal standing potential that exists between the front and the back of the human eye. The EOG signal can be processed separately through the horizontal and vertical channel from the surface muscle around the eye. In this paper, we propose a method to describe the characteristic of EOG signals that can be used to detect eye movements. The method consists of two (2) main parts: recurrence quantification analysis to estimate the behavior of EOG signal and state space analysis to identify different types of eye movement. The assessment of the data suggests the potential parameters in characterizing EOG signal. The preliminary results indicate that state space analysis is...
Daily administration of vitamin D is important for maintaining bone homeostasis. The orthopedic c... more Daily administration of vitamin D is important for maintaining bone homeostasis. The orthopedic community has shown increased interest in vitamin D supplementation and patient outcomes after fracture. The current study used data from a large hip fracture trial to determine the proportion of patients who consistently used vitamin D after hip fracture surgery and to determine whether supplementation was associated with improved health-related quality of life and reduced reoperation rates. The FAITH study is a multicenter trial of elderly patients with femoral neck fracture treated with internal fixation. The current study asked a subset of patients included in the FAITH study about vitamin D supplementation and categorized them as consistent users, inconsistent users, or nonusers. This study also evaluated whether supplementation was associated with improved quality of life and reduced reoperation rates. The final analysis included 573 patients (mean age, 74.1 years; female, 66.3%; no...
Background High rates of re-operations after initial hip fracture fixation, the associated morbid... more Background High rates of re-operations after initial hip fracture fixation, the associated morbidity, mortality, and costs motivated the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) randomised controlled trial. Methods We randomised 1,079 patients with a low-energy femoral neck fracture fracture requiring fracture fixation in 81 centres to a single large diameter screw with a side-plate (sliding hip screw) or the current standard, multiple small diameter cancellous screws (Clinical Trials Identification Number: NCT01908751). The primary outcome was hip re-operation within 24 months. Health-related quality of life (HRQL) was measured by the SF-12, EQ-5D, and WOMAC score. Findings Re-operations did not convincingly differ by type of surgical fixation: 107 of 542 patients (19•7%) in the sliding hip screw group and 117 of 537 patients (21•8%) in the cancellous screws group (hazard ratio, 0•83; 95% CI, 0•63 to 1•09; p=0•18). Avascular necrosis was more common in the sliding hip screw group than in the cancellous screws group (50 patients [9•2%] vs. 28 patients [5•2%]; hazard ratio, 1•78; 95% CI, 1•09 to 2•91; p=0•02). The three HRQL instruments were consistent in showing no important difference by treatment group at 24 months. A priori subgroups suggested lower reoperation rates with sliding hip screws in patients with displaced fractures (interaction p=0•04), base of femoral neck fractures (interaction p=0•04), and current Page 3 of 33 smokers (interaction p=0•02); current smoking appeared the dominant effect modifier in an analysis that included all three variables. Interpretation Among patients with a femoral neck fracture fracture there was no convincing difference in hip re-operations or HRQL among patients allocated to sliding hip screw compared to cancellous screws. Avascular necrosis was higher with sliding hip screws.
The Journal of bone and joint surgery. American volume, Jan 6, 2015
The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) has been extensively e... more The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) has been extensively evaluated in groups of patients with osteoarthritis, yet not in patients with a femoral neck fracture. This study aimed to determine the reliability, construct validity, and responsiveness of the WOMAC compared with the Short Form-12 (SF-12) and the EuroQol 5D (EQ-5D) questionnaires for the assessment of elderly patients with a femoral neck fracture. Reliability was tested by assessing the Cronbach alpha. Construct validity was determined with the Pearson correlation coefficient. Change scores were calculated from ten weeks to twelve months of follow-up. Standardized response means and floor and ceiling effects were determined. Analyses were performed to compare the results for patients less than eighty years old with those for patients eighty years of age or older. The mean WOMAC total score was 89 points before the fracture in the younger patients and increased from 70 points at ten wee...
With the development of intelligent surveillance systems, the need for accurate detection of pede... more With the development of intelligent surveillance systems, the need for accurate detection of pedestrians by cameras has increased. However, most of the previous studies use a single camera system, either a visible light or thermal camera, and their performances are affected by various factors such as shadow, illumination change, occlusion, and higher background temperatures. To overcome these problems, we propose a new method of detecting pedestrians using a dual camera system that combines visible light and thermal cameras, which are robust in various outdoor environments such as mornings, afternoons, night and rainy days. Our research is novel, compared to previous works, in the following four ways: First, we implement the dual camera system where the axes of visible light and thermal cameras are parallel in the horizontal direction. We obtain a geometric transform matrix that represents the relationship between these two camera axes. Second, two background images for visible light and thermal cameras are adaptively updated based on the pixel difference between an input thermal and pre-stored thermal background images. Third, by background subtraction of thermal image considering the temperature characteristics of background and size filtering with morphological operation, the candidates from whole image (CWI) in the thermal image is obtained. The positions of CWI (obtained by background subtraction and the procedures of shadow removal, morphological operation, size filtering, and filtering of the ratio of height to width) in the visible light image are
The need for computer vision-based human detection has increased in fields, such as security, int... more The need for computer vision-based human detection has increased in fields, such as security, intelligent surveillance and monitoring systems. However, performance enhancement of human detection based on visible light cameras is limited, because of factors, such as nonuniform illumination, shadows and low external light in the evening and night. Consequently, human detection based on thermal (far-infrared light) cameras has been considered as an alternative. However, its performance is influenced by the factors, such as low image resolution, low contrast and the large noises of thermal images. It is also affected by the high temperature of backgrounds during the day. To solve these problems, we propose a new method for detecting human areas in thermal camera images. Compared to previous works, the proposed research is novel in the following four aspects. One background image is generated by median and average filtering. Additional filtering procedures based on maximum gray level, si...
The goal of this study was to compare functional outcomes of patients with patella fractures trea... more The goal of this study was to compare functional outcomes of patients with patella fractures treated with open reduction and internal fixation (ORIF) with those treated with partial patellectomy (PP). Retrospective cohort study. Urban Level I Trauma Center. Seventy-three patients with isolated displaced patella fractures underwent operative treatment between January 1, 2002, and December 31, 2009, at our institution. Of these, 52 (71%) patients with isolated patella fractures with minimum 1-year follow-up agreed to participate and were enrolled in the study. PP or ORIF. Patients completed outcome questionnaires and participated in a physical examination. Outcome instruments included the Knee Outcome Survey-Activities of Daily Living Scale, Short Form (SF)-36 Health Survey, and SF Musculoskeletal Function Assessment Survey. Twenty-six patients underwent PP and 26 underwent ORIF. There were no significant differences in any of the functional outcome instruments, including Knee Outcome...
Geriatric orthopaedic surgery & rehabilitation, 2012
Treatment of complex fracture patterns of the proximal humerus continues to be a challenging and ... more Treatment of complex fracture patterns of the proximal humerus continues to be a challenging and controversial clinical scenario. The aim of this study was to report on the outcomes of complex displaced 3- and 4-part fractures of the proximal humerus treated with locked plating and compare the functional results of patients on the basis of age at time of injury. A retrospective review was completed to identify patients whom had sustained a 3- or 4-part fracture of the proximal humerus (Neer classification), treated surgically with locked compression plating. Patients were recruited for a final follow-up, with clinical (Constant and Disabilities of the Arm, Shoulder, Hand [DASH] scores) and radiographic outcome analysis. Results were compared (t test and Wilcoxon test) with fracture type (3- vs 4-part) and patient age at time of fracture (<65 years vs >65years) as the primary outcome measure. The presence or absence of a complication and presence or absence of a concomitant oss...
The primary goals of surgical fracture management are restoration of function with reliable osseo... more The primary goals of surgical fracture management are restoration of function with reliable osseous healing while minimizing soft-tissue injury, ultimately allowing safe and effective patient rehabilitation. The use of locking constructs has become increasingly popular among orthopaedic surgeons, with the emphasis shifting from rigid fixation in conventional plating, towards a more biological fixation with locked plating. The purpose of this review was to present a synopsis of locking construct technology, including a historical perspective along with a biomechanical principles overview. Additionally, the principles of hybrid plating, along with its indications and drawbacks, are reviewed.
The framework for corporate governance in Vietnam, especially for listed companies, is in the ear... more The framework for corporate governance in Vietnam, especially for listed companies, is in the early stages of development. This study examines the corporate governance of Vietnamese listed companies. Some case studies of the corporate governance of listed companies are provided. The study concludes that listed companies need to improve their corporate governance to ensure market transparency, investor protection and effective management in order to ensure better development of the securities market.
The rapid growth of point-of-care polysomnographic alternatives has necessitated standardized eva... more The rapid growth of point-of-care polysomnographic alternatives has necessitated standardized evaluation and validation frameworks. The current average across participant validation methods may overestimate the agreement between wearable sleep tracker devices and polysomnography (PSG) systems because of the high base rate of sleep during the night and the interindividual difference across the sampling population. This study proposes an evaluation framework to assess the aggregating differences of the sleep architecture features and the chronologically epoch-by-epoch mismatch of the wearable sleep tracker devices and the PSG ground truth. An AASM-based sleep stage categorizing method was proposed to standardize the sleep stages scored by different types of wearable trackers. Sleep features and sleep stage architecture were extracted from the PSG and the wearable device’s hypnograms. Therefrom, a localized quantifier index was developed to characterize the local mismatch of sleep scor...
Understanding of eye movement is crucial for viewers’ behavior recognition. The movement of eyeba... more Understanding of eye movement is crucial for viewers’ behavior recognition. The movement of eyeballs in space can be described by a nonlinear differential equation that should be processed with a special identification approach due to its nonlinearities. Electrooculography (EOG) is a technique for measuring the cornea—retinal standing potential that exists between the front and the back of the human eye. The EOG signal can be processed separately through the horizontal and vertical channel from the surface muscle around the eye. In this paper, we propose a method to describe the characteristic of EOG signals that can be used to detect eye movements. The method consists of two (2) main parts: recurrence quantification analysis to estimate the behavior of EOG signal and state space analysis to identify different types of eye movement. The assessment of the data suggests the potential parameters in characterizing EOG signal. The preliminary results indicate that state space analysis is...
Daily administration of vitamin D is important for maintaining bone homeostasis. The orthopedic c... more Daily administration of vitamin D is important for maintaining bone homeostasis. The orthopedic community has shown increased interest in vitamin D supplementation and patient outcomes after fracture. The current study used data from a large hip fracture trial to determine the proportion of patients who consistently used vitamin D after hip fracture surgery and to determine whether supplementation was associated with improved health-related quality of life and reduced reoperation rates. The FAITH study is a multicenter trial of elderly patients with femoral neck fracture treated with internal fixation. The current study asked a subset of patients included in the FAITH study about vitamin D supplementation and categorized them as consistent users, inconsistent users, or nonusers. This study also evaluated whether supplementation was associated with improved quality of life and reduced reoperation rates. The final analysis included 573 patients (mean age, 74.1 years; female, 66.3%; no...
Background High rates of re-operations after initial hip fracture fixation, the associated morbid... more Background High rates of re-operations after initial hip fracture fixation, the associated morbidity, mortality, and costs motivated the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) randomised controlled trial. Methods We randomised 1,079 patients with a low-energy femoral neck fracture fracture requiring fracture fixation in 81 centres to a single large diameter screw with a side-plate (sliding hip screw) or the current standard, multiple small diameter cancellous screws (Clinical Trials Identification Number: NCT01908751). The primary outcome was hip re-operation within 24 months. Health-related quality of life (HRQL) was measured by the SF-12, EQ-5D, and WOMAC score. Findings Re-operations did not convincingly differ by type of surgical fixation: 107 of 542 patients (19•7%) in the sliding hip screw group and 117 of 537 patients (21•8%) in the cancellous screws group (hazard ratio, 0•83; 95% CI, 0•63 to 1•09; p=0•18). Avascular necrosis was more common in the sliding hip screw group than in the cancellous screws group (50 patients [9•2%] vs. 28 patients [5•2%]; hazard ratio, 1•78; 95% CI, 1•09 to 2•91; p=0•02). The three HRQL instruments were consistent in showing no important difference by treatment group at 24 months. A priori subgroups suggested lower reoperation rates with sliding hip screws in patients with displaced fractures (interaction p=0•04), base of femoral neck fractures (interaction p=0•04), and current Page 3 of 33 smokers (interaction p=0•02); current smoking appeared the dominant effect modifier in an analysis that included all three variables. Interpretation Among patients with a femoral neck fracture fracture there was no convincing difference in hip re-operations or HRQL among patients allocated to sliding hip screw compared to cancellous screws. Avascular necrosis was higher with sliding hip screws.
The Journal of bone and joint surgery. American volume, Jan 6, 2015
The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) has been extensively e... more The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) has been extensively evaluated in groups of patients with osteoarthritis, yet not in patients with a femoral neck fracture. This study aimed to determine the reliability, construct validity, and responsiveness of the WOMAC compared with the Short Form-12 (SF-12) and the EuroQol 5D (EQ-5D) questionnaires for the assessment of elderly patients with a femoral neck fracture. Reliability was tested by assessing the Cronbach alpha. Construct validity was determined with the Pearson correlation coefficient. Change scores were calculated from ten weeks to twelve months of follow-up. Standardized response means and floor and ceiling effects were determined. Analyses were performed to compare the results for patients less than eighty years old with those for patients eighty years of age or older. The mean WOMAC total score was 89 points before the fracture in the younger patients and increased from 70 points at ten wee...
With the development of intelligent surveillance systems, the need for accurate detection of pede... more With the development of intelligent surveillance systems, the need for accurate detection of pedestrians by cameras has increased. However, most of the previous studies use a single camera system, either a visible light or thermal camera, and their performances are affected by various factors such as shadow, illumination change, occlusion, and higher background temperatures. To overcome these problems, we propose a new method of detecting pedestrians using a dual camera system that combines visible light and thermal cameras, which are robust in various outdoor environments such as mornings, afternoons, night and rainy days. Our research is novel, compared to previous works, in the following four ways: First, we implement the dual camera system where the axes of visible light and thermal cameras are parallel in the horizontal direction. We obtain a geometric transform matrix that represents the relationship between these two camera axes. Second, two background images for visible light and thermal cameras are adaptively updated based on the pixel difference between an input thermal and pre-stored thermal background images. Third, by background subtraction of thermal image considering the temperature characteristics of background and size filtering with morphological operation, the candidates from whole image (CWI) in the thermal image is obtained. The positions of CWI (obtained by background subtraction and the procedures of shadow removal, morphological operation, size filtering, and filtering of the ratio of height to width) in the visible light image are
The need for computer vision-based human detection has increased in fields, such as security, int... more The need for computer vision-based human detection has increased in fields, such as security, intelligent surveillance and monitoring systems. However, performance enhancement of human detection based on visible light cameras is limited, because of factors, such as nonuniform illumination, shadows and low external light in the evening and night. Consequently, human detection based on thermal (far-infrared light) cameras has been considered as an alternative. However, its performance is influenced by the factors, such as low image resolution, low contrast and the large noises of thermal images. It is also affected by the high temperature of backgrounds during the day. To solve these problems, we propose a new method for detecting human areas in thermal camera images. Compared to previous works, the proposed research is novel in the following four aspects. One background image is generated by median and average filtering. Additional filtering procedures based on maximum gray level, si...
The goal of this study was to compare functional outcomes of patients with patella fractures trea... more The goal of this study was to compare functional outcomes of patients with patella fractures treated with open reduction and internal fixation (ORIF) with those treated with partial patellectomy (PP). Retrospective cohort study. Urban Level I Trauma Center. Seventy-three patients with isolated displaced patella fractures underwent operative treatment between January 1, 2002, and December 31, 2009, at our institution. Of these, 52 (71%) patients with isolated patella fractures with minimum 1-year follow-up agreed to participate and were enrolled in the study. PP or ORIF. Patients completed outcome questionnaires and participated in a physical examination. Outcome instruments included the Knee Outcome Survey-Activities of Daily Living Scale, Short Form (SF)-36 Health Survey, and SF Musculoskeletal Function Assessment Survey. Twenty-six patients underwent PP and 26 underwent ORIF. There were no significant differences in any of the functional outcome instruments, including Knee Outcome...
Geriatric orthopaedic surgery & rehabilitation, 2012
Treatment of complex fracture patterns of the proximal humerus continues to be a challenging and ... more Treatment of complex fracture patterns of the proximal humerus continues to be a challenging and controversial clinical scenario. The aim of this study was to report on the outcomes of complex displaced 3- and 4-part fractures of the proximal humerus treated with locked plating and compare the functional results of patients on the basis of age at time of injury. A retrospective review was completed to identify patients whom had sustained a 3- or 4-part fracture of the proximal humerus (Neer classification), treated surgically with locked compression plating. Patients were recruited for a final follow-up, with clinical (Constant and Disabilities of the Arm, Shoulder, Hand [DASH] scores) and radiographic outcome analysis. Results were compared (t test and Wilcoxon test) with fracture type (3- vs 4-part) and patient age at time of fracture (<65 years vs >65years) as the primary outcome measure. The presence or absence of a complication and presence or absence of a concomitant oss...
The primary goals of surgical fracture management are restoration of function with reliable osseo... more The primary goals of surgical fracture management are restoration of function with reliable osseous healing while minimizing soft-tissue injury, ultimately allowing safe and effective patient rehabilitation. The use of locking constructs has become increasingly popular among orthopaedic surgeons, with the emphasis shifting from rigid fixation in conventional plating, towards a more biological fixation with locked plating. The purpose of this review was to present a synopsis of locking construct technology, including a historical perspective along with a biomechanical principles overview. Additionally, the principles of hybrid plating, along with its indications and drawbacks, are reviewed.
The framework for corporate governance in Vietnam, especially for listed companies, is in the ear... more The framework for corporate governance in Vietnam, especially for listed companies, is in the early stages of development. This study examines the corporate governance of Vietnamese listed companies. Some case studies of the corporate governance of listed companies are provided. The study concludes that listed companies need to improve their corporate governance to ensure market transparency, investor protection and effective management in order to ensure better development of the securities market.
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