Sehyung Park

Human computer cooperation in interactive motion planning

This paper presents an interactive motion planning system that generates collision-free motions of robots or objects. The problem of planning collision-free motions has a high complexity, and most motion-planning programs often take a long time to plan motions when the environment is cluttered. Humans on the other use a set of learned heuristics to effortlessly plan collision-free motions, but do not have as good of an accuracy in geometric collision checking as the motion-planning programs. The proposed system provides the user with a facility to utilize the heuristic power of humans along with the algorithmic power and the geometric accuracy of motion-planning programs. More specifically, the user performs a global analysis of the environment and specifies robots configurations (called subgoals) critical to finding a collision-free path, while a motion-planning program performs collision checking and finds a collision-free paths between subgoals. It has resulted in a system that is much more powerful and efficient than either a human or a computer algorithm in motion planning tasks. This system is expected to reduce motion planning time drastically for tele-operated robot manipulators and for verification of feasible part motions in mechanical assembly.

Design of haptic interface for brickout game

This paper introduces a haptic interface for brick games. Conventionally the game user uses mouse or keyboard to play the brick game. However, these input devices do not provide intuitive interface for the game and any tactile feedback to the user. We use a haptic dial to add tactile feedback to enhance game effects in addition to visual and sound effects. The user changes the position of the paddle by spinning the dial knob and feels various tactile feedbacks according to the game context. Tactile feedbacks include friction, jog dial, barrier, detent, and any combinations of these effects which are programmed based on the amount, frequency, and direction of torque along the rotational path. These effects are used as either penalties or useful tools. The proposed haptic dial interface makes the game more fun and gives a very intuitive interface to the game user.

Managing Design Knowledge: Active Document System

Abstract Sharing design knowledge within a company is critical to retain market competitiveness, especially when the company develops a family of products. The goal of this study is to develop a Web-based design knowledge management system, named Active Document System, that helps designers retrieve critical design information promptly. In order to manage unstructured knowledge such as design know-how systematically, Active Document System classifies design knowledge in accordance with product functions as well as product structures. This paper explains Active Document System and a method to deploy the product function. The concept is implemented and applied to the management of design knowledge for the refrigerator design process.

Markerless registration for intracerebral hemorrhage surgical system using weighted Iterative Closest Point (ICP)

It is required to use a stereotactic frame on a patients crainial surface to access an intracerebral hematoma in conventional ICH (Intracerebral Hemorrhage) removal surgery. Since ICH using a stereotactic frame is an invasive procedure and also takes a long time, we attempt to develop a robotic ICH removal procedure with a markerless registration system using an optical 3-D scanner. Preoperative planning is performed using a patients CT (Computed Tomography) images, which include the patients 3-D geometrical information on the hematoma and internal structures of brain. To register the preplanned data and the intraoperative patients data, the patients facial surface is scanned by an optical 3-D scanner on the bed in the operating room. The intraoperatively scanned facial surface is registered to the pose of the patients preoperative facial surface. The conventional ICP (Iterative Closest Point) algorithm can be used for the registration. In this paper, we propose a weighted ICP in order to improve the accuracy of the registration results. We investigated facial regions that can be used as anatomical landmarks. The facial regions for the landmarks in the preoperative 3-D model are weighted for more accurate registration. We increase weights at the relatively undeformed facial regions, and decrease weights at the other regions. As a result, more accurate and robust registration can be achieved from the preoperative data even with local facial shape changes.

An universal remote controller with haptic interface for home devices

We introduce a new universal remote controller that gives easy-to-control interface for home devices such as TV, video/audio player, room lighting and temperature control. In order to use a conventional remote controller, one should study an instruction manual and remember function for each button. In addition, the remote controller does not provide an intuitive interface so the user has difficulty in searching the right button among a lot of small buttons. Our remote controller addresses these limitations by using a touch screen, a force-feedback dial knob, and a single button instead of many buttons. We suggest an example scenario to interact with a conventional TV set using our remote controller.

Factors affecting capsular volume changes and association with outcomes after Bankart repair and capsular shift.

Background: Capsular laxity is a main contributing factor in recurrent shoulder instability and is suggested to be correlated with increased capsular volume. Arthroscopic capsular shift combined with Bankart repair can reduce the capsular volume and reinforce the redundant capsule; however, as the capsuloligamentous structure has viscoelastic properties, it is possible for the shifted and tensioned capsule of the glenohumeral joint to slowly stretch out again over time, resulting in an increase in capsular volume. Purpose: To analyze changes in capsular volume of the glenohumeral joint over time after arthroscopic Bankart repair and capsular shift, the factors associated with these changes, and their relevance to outcomes. Study Design: Case series; Level of evidence, 4. Methods: Included in this study were 105 patients (mean age, 25.8 ± 8.2 years) who underwent arthroscopic Bankart repair and capsular shift for anterior shoulder instability and computed tomography arthrography (CTA) at 3 months and 1 year postoperatively and whose various functional outcomes were evaluated preoperatively and at the last follow-up (>12 months). Among these patients, 27 also had preoperative CTA. These 27 patients were used to make comparisons between preoperative and 3-month postoperative CTA measurements, and all 105 patients were used for all other comparisons. Two raters measured the separate anterior and posterior capsular volume and cross-sectional area at the 5-o’clock position using 3-dimensional (3D) Slicer software. These measurements were subsequently adjusted for each glenoid size. The changes in capsular volume and cross-sectional area at the 5-o’clock position over time, the factors related to higher change in anterior capsular volume, and their correlation with outcomes were evaluated. Results: Three months postoperatively, the total and anterior capsular volume and anterior cross-sectional area significantly decreased; however, these values increased again at 1 year postoperatively (all P < .01). The inter- and intraobserver reliabilities of the measurements were excellent (interclass correlation coefficient = 0.717-0.945). Female sex, being an elite athlete, and more dislocations before surgery were related to a higher increase in anterior capsular volume at 1 year (all P < .05). Eight patients had redislocation, and 18 exhibited positive apprehension test postoperatively, and these patients showed significantly higher increases in anterior and total capsular volume at 1 year than did those without redislocation or positive apprehension sign (all P < .01). However, with the exception of Rowe score, a higher increase in anterior capsular volume was not related to functional outcome measures. Conclusion: Surgeons should be aware of the re-increase in anterior capsular volume or restretching trait of the anterior capsule over time, even after successful arthroscopic Bankart repair and capsular shift. In this study, women, elite athletes, and those with frequent dislocations were at high risk of capsular restretching. An increase in capsular volume was related to redislocation and positive apprehension sign as well as with Rowe score.

Automatic segmentation of leg bones by using active contours

In this paper, we present a new active contours model to segment human leg bones in computed tomography images that is based on a variable-weighted combination of local and global intensity. This model can split an object surrounded by both weak and strong boundaries, and also distinguish very adjacent objects with those boundaries. The ability of this model is required for segmentation in medical images, e.g., human leg bones, which are usually composed of highly inhomogeneous objects and where the distances among organs are very close. We developed an evolution equation of a level set function whose zero level set represents a contour. An initial contour is automatically obtained by applying a histogram based multiphase segmentation method. We experimented with computed tomography images from three patients, and demonstrate the efficiency of the proposed method in experimental results.

A phantom study on the propagation of NIR rays under the skin for designing a novel vein-visualizing device

Recently, by compensating shortcomings of existing ones, a novel vein-visualizing device was proposed. It highly improves the intuitiveness and the accuracy of venipuncture, but further developments are still required. In this study, as a preliminary work for the device, a phantom experiment was conducted on the propagation of NIR rays under the skin. For this, a NIR diode module and an agar phantom including a vein model were produced, and then, the propagation of NIR rays inside of the phantom was captured by an IR camera. If NIR rays are casted perpendicularly to the surface just above the vein model, the vein model can take much light, but the skin must be occluded with the NIR diode module. Also, if the module is shifted in order to get a wide field of vision, the vein model may not receive enough light. However, in the case of a large incidence angle, enough NIR rays can reach the vein model, and simultaneously, a wide field of vision can be obtained.

An electronic aid for a visually impaired person using an ultrasonic sensor

This paper presents an electronic device, called SmartWand, which can help a visually impaired person walk around more safely. Attached to a conventional white cane, the SmartWand detects obstacles that cannot be detected by a traditional cane and gives warnings in the forms of vibration or sound. In addition to obstacle detection, it also provides functions to detect colors of objects and the brightness of surroundings.

Registration accuracy enhancement of a surgical navigation system for anterior cruciate ligament reconstruction: A phantom and cadaveric study

BACKGROUND Recently, surgical navigation systems have been widely used to improve the results of various orthopaedic surgeries. However, surgical navigation has not been successful in anterior cruciate ligament reconstruction, owing to its inaccuracy and inconvenience. This study investigated the registration of preoperative and intraoperative data, which are the key components in improving accuracy of the navigation system. METHODS An accurate registration method was proposed using new optical tracking markers and landmark retake. A surgical planning and navigation system for anterior cruciate ligament reconstruction was developed and implemented. The accuracy of the proposed system has been evaluated using phantoms and eight cadaveric knees. The present study investigated only the registration accuracy excluding the errors of optical tracking hardware and surgeon. RESULTS The target registration errors of femoral tunnelling for anterior cruciate ligament reconstruction in phantoms were found to be 0.24±0.03mm and 0.19±0.10° for the tunnel entry position and tunnel direction, respectively. The target registration errors measured using cadavers were 0.9mm and 1.94°, respectively. CONCLUSIONS The preclinical experimental results showed that the proposed methods enhanced the registration accuracy of the developed system. As the system becomes more accurate, surgeons could more precisely position and orient the femoral and tibial tunnels to their original anatomical locations.