Peder Pedersen - Academia.edu (original) (raw)
Papers by Peder Pedersen
IEEE Open Journal of Engineering in Medicine and Biology
Augment a small, imbalanced, wound dataset by using semi-supervised learning with a secondary dat... more Augment a small, imbalanced, wound dataset by using semi-supervised learning with a secondary dataset. Then utilize the augmented wound dataset for deep learning-based wound assessment.
IEEE Access, 2020
Smartphone wound image analysis has recently emerged as a viable way to assess healing progress a... more Smartphone wound image analysis has recently emerged as a viable way to assess healing progress and provide actionable feedback to patients and caregivers between hospital appointments. Segmentation is a key image analysis step, after which attributes of the wound segment (e.g. wound area and tissue composition) can be analyzed. The Associated Hierarchical Random Field (AHRF) formulates the image segmentation problem as a graph optimization problem. Handcrafted features are extracted, which are then classified using machine learning classifiers. More recently deep learning approaches have emerged and demonstrated superior performance for a wide range of image analysis tasks. FCN, U-Net and DeepLabV3 are Convolutional Neural Networks used for semantic segmentation. While in separate experiments each of these methods have shown promising results, no prior work has comprehensively and systematically compared the approaches on the same large wound image dataset, or more generally compared deep learning vs non-deep learning wound image segmentation approaches. In this paper, we compare the segmentation performance of AHRF and CNN approaches (FCN, U-Net, DeepLabV3) using various metrics including segmentation accuracy (dice score), inference time, amount of training data required and performance on diverse wound sizes and tissue types. Improvements possible using various image pre-and post-processing techniques are also explored. As access to adequate medical images/data is a common constraint, we explore the sensitivity of the approaches to the size of the wound dataset. We found that for small datasets (<300 images), AHRF is more accurate than U-Net but not as accurate as FCN and DeepLabV3. AHRF is also over 1000x slower. For larger datasets (>300 images), AHRF saturates quickly, and all CNN approaches (FCN, U-Net and DeepLabV3) are significantly more accurate than AHRF. INDEX TERMS Wound image analysis, semantic segmentation, chronic wounds, U-Net, FCN, DeepLabV3, associative hierarchical random fields, convolutional neural network, contrast limited adaptive histogram equalization. I. INTRODUCTION Diabetes Mellitus is a serious medical condition that affected 30.3 million people in 2017 [1]. About 15% of diabetes patients have chronic wounds in the US, which has a The associate editor coordinating the review of this manuscript and approving it for publication was Ruqiang Yan.
Chronic wounds are expensive to treat and have a significant impact on patients' quality of l... more Chronic wounds are expensive to treat and have a significant impact on patients' quality of life [1]. Due to lack of access to wound experts, patients usually receive care from non-expert clinicians who have limited chronic wound assessment skills. Clinical decision support systems (CDSS) can assist these non-expert clinicians. This research in progress is part of an ongoing project working on developing a smartphone based wound CDSS to support non-expert clinicians during wound assessments in remote settings. Since each chronic wound type has a different assessment and management procedure, this paper focused on building a decision model that supports users in determining the type of chronic wounds so that we can later guide them on the proper evidence based decision path.We used design science research methodology (DSRM) model by Peffers et al. [2] to design rule-based decision models that can assess chronic wound type efficiently using wound photos and simple clinical values ...
Pathway to Recommended Decisions within SMARTWAnDS App. Figure belongs to ERF paper presented to ... more Pathway to Recommended Decisions within SMARTWAnDS App. Figure belongs to ERF paper presented to Americas Conference on Information Systems (AMCIS) has gathered leaders from the field of Information Systems together to present a broad variety of research and teaching topics. For the first time in its history, AMCIS, August 2020.
32nd Annual Frontiers in Education
32nd Annual Frontiers in Education
All WPI undergraduate students complete three required projects, including a senior-level capston... more All WPI undergraduate students complete three required projects, including a senior-level capstone design project that is equivalent in credit to three courses. Over 50% of WPI students complete at least one of their projects overseas at one of WPI's residential Project Centers located around the globe. Here, we describe two Project Centersin Limerick, Ireland and Copenhagen, Denmark-at which teams of WPI students spend an academic term completing electrical and computer engineering design projects for industrial sponsors. Examples of student projects are given, as are details of the learning outcomes and accreditation evidence they provide. Finally, logistical and operational issues are discussed.
Proceedings 2000 IEEE EMBS International Conference on Information Technology Applications in Biomedicine. ITAB-ITIS 2000. Joint Meeting Third IEEE EMBS International Conference on Information Technology Applications in Biomedicine (ITAB'00). Third Works, 2000
Abstract The paper presents a specialty wireless telemedicine application, namely wireless ultras... more Abstract The paper presents a specialty wireless telemedicine application, namely wireless ultrasound, and describe its place in the growing wireless telemedicine market. We address the needs of current wireless telemedicine applications by presenting software additions ...
2013 IEEE International Conference on Healthcare Informatics, 2013
Running is a popular physical activity that improves physical and mental wellbeing. Unfortunately... more Running is a popular physical activity that improves physical and mental wellbeing. Unfortunately, up-todate information about runners' performance and psychological wellbeing is limited. Many questions remain unanswered, such as how far and how fast runners typically run, their preferred running times and frequencies, how long new runners persist before dropping out, and what factors cause runners to quit. Without hard data, establishing patterns of runner behavior and mitigating challenges they face are difficult. Collecting data manually from large numbers of runners for research studies is costly and time consuming. Emerging Social Networking Services (SNS) and fitness tracking devices make tracking and sharing personal physical activity information easier than before. By monitoring the tweets of a runner group on Twitter (SNS) over a 3-month period, we collected 929,825 messages (tweets), in which runners used Nike+ fitness trackers while running. We found that (1) fitness trackers were most popular in North America (2) one third of runners dropped out after one run (3) Over 95% of runners ran for at least 10 minutes per session (4) less than 2% of runners consistently ran for at least 150 minutes a week, which is the level of physical activity recommended by the CDC (5) 5K was the most popular distance.
2013 IEEE International Workshop of Internet-of-Things Networking and Control (IoT-NC), 2013
ABSTRACT Over one billion smartphones have now been shipped worldwide. These mobile devices featu... more ABSTRACT Over one billion smartphones have now been shipped worldwide. These mobile devices feature multi-core CPUs and GPUs, megapixel cameras and an array of sensors. Smartphone sensors can now be processed to diagnose a wide variety of medical conditions including cough detection, irregular heartbeat detection, and lung function analysis. The ability to diagnose ailments in the convenience of patients' homes on smartphones that they already possess could lead to early detection, which could ultimately reduce healthcare costs. This paper reviews state-of-the-art examples, examines the technical issues involved in the use of the smartphone as a medical device, and outlines potential benefits and challenges. A case study of an Android smartphone app for wound detection and healing progress analysis by diabetes patients is also presented.
Medical Imaging 2006: Ultrasonic Imaging and Signal Processing, 2006
IEEE Open Journal of Engineering in Medicine and Biology
Goal: Chronic wounds affect 6.5 million Americans. Wound assessment via algorithmic analysis of s... more Goal: Chronic wounds affect 6.5 million Americans. Wound assessment via algorithmic analysis of smartphone images has emerged as a viable option for remote assessment. Methods: We comprehensively score wounds based on the clinically-validated Photographic Wound Assessment Tool (PWAT), which comprehensively assesses clinically important ranges of eight wound attributes: Size, Depth, Necrotic Tissue Type, Necrotic Tissue Amount, Granulation Tissue type, Granulation Tissue Amount, Edges, Periulcer Skin Viability. We proposed a DenseNet Convolutional Neural Network (CNN) framework with patch-based context-preserving attention to assess the 8 PWAT attributes of four wound types: diabetic ulcers, pressure ulcers, vascular ulcers and surgical wounds. Results: In an evaluation on our dataset of 1639 wound images, our model estimated all 8 PWAT sub-scores with classification accuracies and F1 scores of over 80%. Conclusions: Our work is the first intelligent system that autonomously grades wounds comprehensively based on criteria in the PWAT rubric, alleviating the significant burden that manual wound grading imposes on wound care nurses. Index Terms-Chronic wounds, deep learning, medical imaging, smartphone assessment, transfer learning. Impact Statement-We proposed a CNN Densenet with context-preserving attention mechanism that assess all 8 PWAT sub-scores for chronic wound images and achieves classification accuracies and F1 scores of over 0.8.
IEEE 30th Annual Northeast Bioengineering Conference, 2004. Proceedings of the
An important aspect of diagnostic ultrasound is a good visualization of organ or tissue surfaces.... more An important aspect of diagnostic ultrasound is a good visualization of organ or tissue surfaces. The goal of the ultrasound image enhancement method presented in this paper is to selectively enhance the clarity of anatomical structures of a specified geometry, such as arteries. With ultrasound array transducers, e.g. linear and annular arrays, a large number of different insonifying ultrasound fields can be produced, including ultrasound fields which will maximize the energy of the received signal for a given transducer and reflector geometry. The calculation of such fields is described in this paper.
2006 IEEE Ultrasonics Symposium
Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society
An ultrasound measurement system is described that will generate the acoustic impedance profile o... more An ultrasound measurement system is described that will generate the acoustic impedance profile of a layered medium from the reflection impulse response and with a priori knowledge of the transmitting/receiving transducers and the attenuation of the medium. The theory, the experimental system, and results are presented. The signal processing includes Weiner filtering for the purpose of compensating for the bandlimited response of the transducers, attenuation compensation, detection of the reflection location and amplitude, and the impedance profile reconstruction from the train of reflection impulses. Measurements have been carried out on multilayered phantoms constructed from thin layers. Results are presented for a three-layer phantom.<<ETX>>
IEEE 1984 Ultrasonics Symposium
This paper briefly outlines a spectral analysis procedure for qualitative characterization of ult... more This paper briefly outlines a spectral analysis procedure for qualitative characterization of ultrasound transducers and presents applications of the procedure for the assessment of acoustic parameters. The parameters include the transmitting and receiving frequency response, directivity pattern and effective aperture of different shape piezoelectric tranceivers. The advantages and fundamental limitations of the spectral analysis technique are discussed in terms of frequency range, signal to noise ratio and dynamic range. Experimental data are presented which show that the technique is extremely useful in transducer performance evaluation as a continuous function of frequency. Future applications of the technique, including complex, i.e. both amplitude and phase, characterization of ultrasound piezoelectric transducers, are also pointed out.
6th IEEE Conference Record., Instrumentation and Measurement Technology Conference
The author describes a digitally implemented coherent sweep generator, i.e. a sweep generator in ... more The author describes a digitally implemented coherent sweep generator, i.e. a sweep generator in which sweep rate, start frequency and start phase can be specified. By carrying out a digital integration twice, using a counter and an accumulator as the integrators, the quadratic phase function of a linear sweep is produced. The desired start frequency and start phase are introduced by presetting the counter and accumulator, respectively. The mod (2 pi ) of the quadratic phase function is extracted and used as address for a sine lookup table whose output is applied to a digital-to-analog converter. The system is capable of producing sweep signals from DC up to the lower MHz range, and the sweep rate can be varied over several orders of magnitude. By operating several digital sweep generators from the same clock, multiple coherent sweep signals can be produced. The digital sweep generator has been implemented with transistor-transistor logic, and generated waveforms are presented.<<ETX>>
IEEE transactions on bio-medical engineering, Sep 23, 2016
It is standard practice for clinicians and nurses to primarily assess patients' wounds via vi... more It is standard practice for clinicians and nurses to primarily assess patients' wounds via visual examination. This subjective method can be inaccurate in wound assessment and also represents a significant clinical workload. Hence, computer-based systems, especially implemented on mobile devices, can provide automatic, quantitative wound assessment and can thus be valuable for accurately monitoring wound healing status. Out of all wound assessment parameters, the measurement of the wound area is the most suitable for automated analysis. Most of the current wound boundary determination methods only process the image of the wound area along with a small amount of surrounding healthy skin. In this paper, we present a novel approach that uses Support Vector Machine (SVM) to determine the wound boundary on a foot ulcer image captured with an image capture box, which provides controlled lighting, angle and range conditions. The Simple Linear Iterative Clustering (SLIC) method is appli...
2016 49th Hawaii International Conference on System Sciences (HICSS), 2016
We developed a health and wellness smartphone app to support diabetes self-management. The target... more We developed a health and wellness smartphone app to support diabetes self-management. The target users are older, less healthy adults with advanced type 2 diabetes. We illustrate the design implications of a health and wellness smartphone app for such users by presenting the process and results of our usability and user experience lab test with our app.
IEEE Open Journal of Engineering in Medicine and Biology
Augment a small, imbalanced, wound dataset by using semi-supervised learning with a secondary dat... more Augment a small, imbalanced, wound dataset by using semi-supervised learning with a secondary dataset. Then utilize the augmented wound dataset for deep learning-based wound assessment.
IEEE Access, 2020
Smartphone wound image analysis has recently emerged as a viable way to assess healing progress a... more Smartphone wound image analysis has recently emerged as a viable way to assess healing progress and provide actionable feedback to patients and caregivers between hospital appointments. Segmentation is a key image analysis step, after which attributes of the wound segment (e.g. wound area and tissue composition) can be analyzed. The Associated Hierarchical Random Field (AHRF) formulates the image segmentation problem as a graph optimization problem. Handcrafted features are extracted, which are then classified using machine learning classifiers. More recently deep learning approaches have emerged and demonstrated superior performance for a wide range of image analysis tasks. FCN, U-Net and DeepLabV3 are Convolutional Neural Networks used for semantic segmentation. While in separate experiments each of these methods have shown promising results, no prior work has comprehensively and systematically compared the approaches on the same large wound image dataset, or more generally compared deep learning vs non-deep learning wound image segmentation approaches. In this paper, we compare the segmentation performance of AHRF and CNN approaches (FCN, U-Net, DeepLabV3) using various metrics including segmentation accuracy (dice score), inference time, amount of training data required and performance on diverse wound sizes and tissue types. Improvements possible using various image pre-and post-processing techniques are also explored. As access to adequate medical images/data is a common constraint, we explore the sensitivity of the approaches to the size of the wound dataset. We found that for small datasets (<300 images), AHRF is more accurate than U-Net but not as accurate as FCN and DeepLabV3. AHRF is also over 1000x slower. For larger datasets (>300 images), AHRF saturates quickly, and all CNN approaches (FCN, U-Net and DeepLabV3) are significantly more accurate than AHRF. INDEX TERMS Wound image analysis, semantic segmentation, chronic wounds, U-Net, FCN, DeepLabV3, associative hierarchical random fields, convolutional neural network, contrast limited adaptive histogram equalization. I. INTRODUCTION Diabetes Mellitus is a serious medical condition that affected 30.3 million people in 2017 [1]. About 15% of diabetes patients have chronic wounds in the US, which has a The associate editor coordinating the review of this manuscript and approving it for publication was Ruqiang Yan.
Chronic wounds are expensive to treat and have a significant impact on patients' quality of l... more Chronic wounds are expensive to treat and have a significant impact on patients' quality of life [1]. Due to lack of access to wound experts, patients usually receive care from non-expert clinicians who have limited chronic wound assessment skills. Clinical decision support systems (CDSS) can assist these non-expert clinicians. This research in progress is part of an ongoing project working on developing a smartphone based wound CDSS to support non-expert clinicians during wound assessments in remote settings. Since each chronic wound type has a different assessment and management procedure, this paper focused on building a decision model that supports users in determining the type of chronic wounds so that we can later guide them on the proper evidence based decision path.We used design science research methodology (DSRM) model by Peffers et al. [2] to design rule-based decision models that can assess chronic wound type efficiently using wound photos and simple clinical values ...
Pathway to Recommended Decisions within SMARTWAnDS App. Figure belongs to ERF paper presented to ... more Pathway to Recommended Decisions within SMARTWAnDS App. Figure belongs to ERF paper presented to Americas Conference on Information Systems (AMCIS) has gathered leaders from the field of Information Systems together to present a broad variety of research and teaching topics. For the first time in its history, AMCIS, August 2020.
32nd Annual Frontiers in Education
32nd Annual Frontiers in Education
All WPI undergraduate students complete three required projects, including a senior-level capston... more All WPI undergraduate students complete three required projects, including a senior-level capstone design project that is equivalent in credit to three courses. Over 50% of WPI students complete at least one of their projects overseas at one of WPI's residential Project Centers located around the globe. Here, we describe two Project Centersin Limerick, Ireland and Copenhagen, Denmark-at which teams of WPI students spend an academic term completing electrical and computer engineering design projects for industrial sponsors. Examples of student projects are given, as are details of the learning outcomes and accreditation evidence they provide. Finally, logistical and operational issues are discussed.
Proceedings 2000 IEEE EMBS International Conference on Information Technology Applications in Biomedicine. ITAB-ITIS 2000. Joint Meeting Third IEEE EMBS International Conference on Information Technology Applications in Biomedicine (ITAB'00). Third Works, 2000
Abstract The paper presents a specialty wireless telemedicine application, namely wireless ultras... more Abstract The paper presents a specialty wireless telemedicine application, namely wireless ultrasound, and describe its place in the growing wireless telemedicine market. We address the needs of current wireless telemedicine applications by presenting software additions ...
2013 IEEE International Conference on Healthcare Informatics, 2013
Running is a popular physical activity that improves physical and mental wellbeing. Unfortunately... more Running is a popular physical activity that improves physical and mental wellbeing. Unfortunately, up-todate information about runners' performance and psychological wellbeing is limited. Many questions remain unanswered, such as how far and how fast runners typically run, their preferred running times and frequencies, how long new runners persist before dropping out, and what factors cause runners to quit. Without hard data, establishing patterns of runner behavior and mitigating challenges they face are difficult. Collecting data manually from large numbers of runners for research studies is costly and time consuming. Emerging Social Networking Services (SNS) and fitness tracking devices make tracking and sharing personal physical activity information easier than before. By monitoring the tweets of a runner group on Twitter (SNS) over a 3-month period, we collected 929,825 messages (tweets), in which runners used Nike+ fitness trackers while running. We found that (1) fitness trackers were most popular in North America (2) one third of runners dropped out after one run (3) Over 95% of runners ran for at least 10 minutes per session (4) less than 2% of runners consistently ran for at least 150 minutes a week, which is the level of physical activity recommended by the CDC (5) 5K was the most popular distance.
2013 IEEE International Workshop of Internet-of-Things Networking and Control (IoT-NC), 2013
ABSTRACT Over one billion smartphones have now been shipped worldwide. These mobile devices featu... more ABSTRACT Over one billion smartphones have now been shipped worldwide. These mobile devices feature multi-core CPUs and GPUs, megapixel cameras and an array of sensors. Smartphone sensors can now be processed to diagnose a wide variety of medical conditions including cough detection, irregular heartbeat detection, and lung function analysis. The ability to diagnose ailments in the convenience of patients' homes on smartphones that they already possess could lead to early detection, which could ultimately reduce healthcare costs. This paper reviews state-of-the-art examples, examines the technical issues involved in the use of the smartphone as a medical device, and outlines potential benefits and challenges. A case study of an Android smartphone app for wound detection and healing progress analysis by diabetes patients is also presented.
Medical Imaging 2006: Ultrasonic Imaging and Signal Processing, 2006
IEEE Open Journal of Engineering in Medicine and Biology
Goal: Chronic wounds affect 6.5 million Americans. Wound assessment via algorithmic analysis of s... more Goal: Chronic wounds affect 6.5 million Americans. Wound assessment via algorithmic analysis of smartphone images has emerged as a viable option for remote assessment. Methods: We comprehensively score wounds based on the clinically-validated Photographic Wound Assessment Tool (PWAT), which comprehensively assesses clinically important ranges of eight wound attributes: Size, Depth, Necrotic Tissue Type, Necrotic Tissue Amount, Granulation Tissue type, Granulation Tissue Amount, Edges, Periulcer Skin Viability. We proposed a DenseNet Convolutional Neural Network (CNN) framework with patch-based context-preserving attention to assess the 8 PWAT attributes of four wound types: diabetic ulcers, pressure ulcers, vascular ulcers and surgical wounds. Results: In an evaluation on our dataset of 1639 wound images, our model estimated all 8 PWAT sub-scores with classification accuracies and F1 scores of over 80%. Conclusions: Our work is the first intelligent system that autonomously grades wounds comprehensively based on criteria in the PWAT rubric, alleviating the significant burden that manual wound grading imposes on wound care nurses. Index Terms-Chronic wounds, deep learning, medical imaging, smartphone assessment, transfer learning. Impact Statement-We proposed a CNN Densenet with context-preserving attention mechanism that assess all 8 PWAT sub-scores for chronic wound images and achieves classification accuracies and F1 scores of over 0.8.
IEEE 30th Annual Northeast Bioengineering Conference, 2004. Proceedings of the
An important aspect of diagnostic ultrasound is a good visualization of organ or tissue surfaces.... more An important aspect of diagnostic ultrasound is a good visualization of organ or tissue surfaces. The goal of the ultrasound image enhancement method presented in this paper is to selectively enhance the clarity of anatomical structures of a specified geometry, such as arteries. With ultrasound array transducers, e.g. linear and annular arrays, a large number of different insonifying ultrasound fields can be produced, including ultrasound fields which will maximize the energy of the received signal for a given transducer and reflector geometry. The calculation of such fields is described in this paper.
2006 IEEE Ultrasonics Symposium
Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society
An ultrasound measurement system is described that will generate the acoustic impedance profile o... more An ultrasound measurement system is described that will generate the acoustic impedance profile of a layered medium from the reflection impulse response and with a priori knowledge of the transmitting/receiving transducers and the attenuation of the medium. The theory, the experimental system, and results are presented. The signal processing includes Weiner filtering for the purpose of compensating for the bandlimited response of the transducers, attenuation compensation, detection of the reflection location and amplitude, and the impedance profile reconstruction from the train of reflection impulses. Measurements have been carried out on multilayered phantoms constructed from thin layers. Results are presented for a three-layer phantom.<<ETX>>
IEEE 1984 Ultrasonics Symposium
This paper briefly outlines a spectral analysis procedure for qualitative characterization of ult... more This paper briefly outlines a spectral analysis procedure for qualitative characterization of ultrasound transducers and presents applications of the procedure for the assessment of acoustic parameters. The parameters include the transmitting and receiving frequency response, directivity pattern and effective aperture of different shape piezoelectric tranceivers. The advantages and fundamental limitations of the spectral analysis technique are discussed in terms of frequency range, signal to noise ratio and dynamic range. Experimental data are presented which show that the technique is extremely useful in transducer performance evaluation as a continuous function of frequency. Future applications of the technique, including complex, i.e. both amplitude and phase, characterization of ultrasound piezoelectric transducers, are also pointed out.
6th IEEE Conference Record., Instrumentation and Measurement Technology Conference
The author describes a digitally implemented coherent sweep generator, i.e. a sweep generator in ... more The author describes a digitally implemented coherent sweep generator, i.e. a sweep generator in which sweep rate, start frequency and start phase can be specified. By carrying out a digital integration twice, using a counter and an accumulator as the integrators, the quadratic phase function of a linear sweep is produced. The desired start frequency and start phase are introduced by presetting the counter and accumulator, respectively. The mod (2 pi ) of the quadratic phase function is extracted and used as address for a sine lookup table whose output is applied to a digital-to-analog converter. The system is capable of producing sweep signals from DC up to the lower MHz range, and the sweep rate can be varied over several orders of magnitude. By operating several digital sweep generators from the same clock, multiple coherent sweep signals can be produced. The digital sweep generator has been implemented with transistor-transistor logic, and generated waveforms are presented.<<ETX>>
IEEE transactions on bio-medical engineering, Sep 23, 2016
It is standard practice for clinicians and nurses to primarily assess patients' wounds via vi... more It is standard practice for clinicians and nurses to primarily assess patients' wounds via visual examination. This subjective method can be inaccurate in wound assessment and also represents a significant clinical workload. Hence, computer-based systems, especially implemented on mobile devices, can provide automatic, quantitative wound assessment and can thus be valuable for accurately monitoring wound healing status. Out of all wound assessment parameters, the measurement of the wound area is the most suitable for automated analysis. Most of the current wound boundary determination methods only process the image of the wound area along with a small amount of surrounding healthy skin. In this paper, we present a novel approach that uses Support Vector Machine (SVM) to determine the wound boundary on a foot ulcer image captured with an image capture box, which provides controlled lighting, angle and range conditions. The Simple Linear Iterative Clustering (SLIC) method is appli...
2016 49th Hawaii International Conference on System Sciences (HICSS), 2016
We developed a health and wellness smartphone app to support diabetes self-management. The target... more We developed a health and wellness smartphone app to support diabetes self-management. The target users are older, less healthy adults with advanced type 2 diabetes. We illustrate the design implications of a health and wellness smartphone app for such users by presenting the process and results of our usability and user experience lab test with our app.