Sungjae Hwang

We simultaneously perturbed visual, vestibular and proprioceptive modalities to understand how sensory feedback is re-weighted so that overall feedback remains suited to stabilizing upright stance. Ten healthy young subjects received an 80 Hz vibratory stimulus to their bilateral Achilles tendons (stimulus turns on-off at 0.28 Hz), a ± 1 mA binaural monopolar galvanic vestibular stimulus at 0.36 Hz, and a visual stimulus at 0.2 Hz during standing. The visual stimulus was presented at different a

Current thinking views mild head impact (i.e., subconcussion) as an underrecognized phenomenon that has the ability to cause significant current and future detrimental neurological effects. Repeated mild impacts to the head, however, often display no observable behavioral deficits based on standard clinical tests, which may lack sensitivity. The current study investigates the effects of subconcussive impacts from soccer heading with innovative measures of vestibular function and walking stabilit

This paper proposes user-customizable passive control widgets, called MagGetz, which enable tangible interaction on and around mobile devices without requiring power or wireless connections. This is achieved by tracking and ana-lyzing the magnetic field generated by controllers attached on and around the device through a single magnetometer, which is commonly integrated in smartphones today. The proposed method provides users with a broader interaction area, customizable input layouts, richer ph

Over the past few years, several studies have been made on haptic devices that help people focus on driving and increase safety. In this paper, we propose a vibro-tactile based display on a steering wheel named “The Haptic Wheel”, which is embedded with 32 linear actuators to present tactile information such as “Alert”, “Turn left” and “Turn right”. This information is coded with spatial and temporal patterns, resulting in the transfer of information regardless of the holding gesture and the num

This paper introduces MagPen, a magnetically driven pen interface that works both on and around mobile devices. The proposed device is accompanied by a new vocabulary of gestures and techniques that increase the expressiveness of the standard capacitive stylus. These techniques are: 1) detecting the orientation that the stylus is pointing to, 2) selecting colors using locations beyond screen boundaries, 3) recognizing different spinning gestures associated with different actions, 4) inferring th

Maintaining upright bipedal posture requires a control system that continually adapts to changing environmental conditions, such as different support surfaces. Behavioral changes associated with different support surfaces, such as the predominance of an ankle or hip strategy, is considered to reflect a change in the control strategy. However, tracing such behavioral changes to a specific component in a closed loop control system is challenging. Here we used the joint input-output (JIO) method of

This paper introduces VibPress, a software technique that enables pressure input interaction on mobile devices by measuring the level of vibration absorption with the built-in accelerometer when the device is in contact with a damping surface (e.g., user's hands). This is achieved using a real-time estimation algorithm running on the device. Through a user evaluation, we provide evidence that this system is faster than previous software-based approaches, and accurate as hardware-augmented approa

In this study, we developed an active ankle-foot orthosis (AAFO) which can control the dorsi/ plantarflexion of the ankle joint to prevent foot drop and toe drag during walking. To prevent slapping foot after heel strike, ankle joint has to be controlled actively to minimize fore foot collision with the ground. In the late stance, ankle joint also has to be controlled to provide the toe clearance and help the push-off. 3D gait analyses were performed on five healthy subjects (age: 27.5plusmn2.1

Ethereum, one of the most popular blockchain platforms, provides financial transactions like payments and auctions through smart contracts. Due to the immense interest in smart contracts in academia, the research community of smart contract security has made a significant improvement recently. Researchers have reported various security vulnerabilities in smart contracts, and developed static analysis tools and verification frameworks to detect them. However, it is unclear whether such great effo

The difficulty that children have in perceiving plants as living entities has been verified by several studies. As an initial attempt to address this issue, we propose My Green Pet, an interactive plant for children. Through this, children enjoy human-like interactions with the plant and also perceive that this particular plant is living. This is achieved by personifying a regular plant by giving it human feelings and emotions, such as pain, joy, laughter, etc. The interactive plant is implement

The foot, an exceedingly complicated system, is essential to move the body forward and to keep dynamic stability during gait. In most previous studies on gait analysis, the foot has been defined as a single rigid segment, which results in many problems to understand the foot motion in detail. The purpose of this study is to develop a multi-segment foot model that can help analyze biomechanics of the foot during gait. A 9-segment foot model with 8 major joints was developed in this study. In addi

Android devices and applications become prevalent and ask for unanticipated capabilities thanks to the increased interests in smartphones and web applications. As a way to use the capabilities not directly available to ordinary users, applications have used Android Debug Bridge (ADB), a command line tool to communicate with Android devices for debugging purposes. While ADB provides powerful features that require permissions to use critical system resources, it opens a gate to adversaries.