Chan-Mo Park

The problem of teleoperating a mobile robot using shared autonomy is addressed: An onboard controller performs close-range obstacle avoidance while the operator uses the manipulandum of a haptic probe to designate the desired speed and rate of turn. Sensors on the robot are used to measure obstacle-range information. A strategy to convert such range information into forces is described, which are reflected to the operator's hand via the haptic probe. This haptic information provides feedback to

Various techniques for object selection in virtual environments have been proposed over the years. Among them, the virtual pointer or ray-casting is one of the most popular method for object selection because it is easy and intuitive to use and allows the user to select objects that are far away. Variants of the virtual pointer metaphor include the Aperture, Flashlight, and Image plane method as categorized as such. In a monoscopic environment, these methods are essentially 2D interaction techni

Development of virtual reality systems requires iterations of specification, implementation and evaluation. Since correct evaluations of immersive VR systems require the tedious process of wearing many devices, there exist both temporal and spatial gaps between the implementation and evaluation stage, and this usually causes delay and inefficiency in the development process. In order to overcome this gap, there have been several approaches to constructing or modeling the physical aspects of the

Usability has become one of the key ingredients in making virtual reality (VR) systems work, and a big part of a usable VR system is the design of effective interface/interaction schemes. We investigate the usability of various menu presentation and multi-modal selection schemes in immersive virtual environments. We have identified five major menu displays and 13 possible menu selection methods; among them, we have completed the usability testing for two interaction methods across the five displ

One of the obstacles to the use of VR is the expensive, intrusive, cumbersome and brittle nature of the sensors required to detect user's intent. While optical tracking has been regarded as one solution to this problem, the problems of establishing marker correspondence and resolving their occlusions remain. One solution is to simply add hardware, making the tracking system too expensive for general usage, while another, to track human body parts, suffers from the inability to track point featur

Virtual studios have long been used in commercial broadcasting. However, most virtual studios are based on "blue screen" technology, and its two-dimensional (2-D) nature restricts the user from making natural three-dimensional (3-D) interactions. Actors have to follow prewritten scripts and pretend as if directly interacting with the synthetic objects. This often creates an unnatural and seemingly uncoordinated output. In this paper, we introduce an improved virtual-studio framework to enable ac

We address the problem of teleoperating a mobile robot using shared autonomy: an on-board controller performs obstacle avoidance while the operator uses the manipulandum of a haptic probe to designate the desired speed and rate of turn. Sensors on the robot are used to measure obstacle range information. We describe a strategy to convert such range information into forces, which are reflected to the operator's hand, via the haptic probe. This haptic information provides feedback to the

We address the problem of teleoperating a mobile robot using shared autonomy: an on-board controller performs obstacle avoidance while the operator uses the manipulandum of a haptic probe to designate the desired speed and rate of turn. Sensors on the robot are used to measure obstacle range information. We describe a strategy to convert such range information into forces, which are reflected to the operator's hand, via the haptic probe. This haptic information provides feedback to the operator

Abstract We present a fast visualization scheme of soft objects by introducing an efficient evaluation method for a field function. The evaluation of a field function includes distance computation between a point in space and the defining primitives of the soft object. If the unnecessary distance computations between a point in space and the components that do not influence the point can be avoided, the evaluation can be accelerated. For this purpose, we decompose the space into adaptive‐sized c

Delaunay triangulation has been much used in such applications as volume rendering, shape representation, terrain modeling and so on. The main disadvantage of Delaunay triangulation is large computation time required to obtain the triangulation on an input points set. This time can be reduced by using more than one processor, and several parallel algorithms for Delaunay triangulation have been proposed. In this paper, we propose an improved parallel algorithm for Delaunay triangulation, which pa

As a parallel system employs more processors to become more complex, it is very hard to understand, evaluate, and tune the system without the aid of the performance information visualization. Many researchers have found that the criteria of good visualization usually include scalability, multiple views, context and user interaction. In spite of much research in performance visualization of a parallel system, only a few results are available which meet those criteria in an integrated fashion. The

Cancer of the cervix is the most common malignancy in women in developing countries and the second most common cancer in women throughout the world with approximately 500,000 new cases each year. Prevention of this large number of premature deaths among women is, therefore, a goal worthy of urgent and serious consideration. Due to its high diagnostic disagreement among pathologists and large quantity of specimens, it is necessary to develop an automatic screening system measuring morphologic and

Abstract A two measurement points pulse techniqque was employed to determine axial dispersion coefficients in a 3/4 inch diameter pipe with four 90 degree bends located at 50 inch intervals. Water velocities corresponding to Reynold numbers of 3,800 to 11,500 were used. It was found that the effect of bends on the overall dispersion coefficient depends on the Reynolds number and a characteristic length. Two mathematical models of a reactor with bends are presented. One model assumed that the ben