Sang Choi

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Models of molecular evolution tend to be overly simplistic caricatures of biology that are prone to assigning high probabilities to biologically implausible DNA or protein sequences. Here, we explore how to construct time-reversible evolutionary models that yield stationary distributions of sequences that match given target distributions. By adopting(More)
Current manufacturing trends require industrial robot to be more and more accurate in order to accomplish more and more complicated manufacturing processes. Robot calibration enables standard robots to achieve higher accuracies. Many complex and/or expensive calibration methodologies have been developed and implemented successfully. However, they are(More)
The latest trends show that industrial robots have been used more and more to increase productivity and quality in general industries other than the traditional automotive industry. Instead of programming the robot by teaching the positions, offline programming has become more popular. User can simulate the programs in the computer first and the(More)
This paper presents a robotic system that performs the steel-strapping process of coils for the metals industry. In the metal coil manufacturing plant, the packaging of coil-product is conventionally performed by dedicated machines specially designed for different strapping modes, such as outer circumference, eye-cross/parallel, vertical, horizontal or(More)
This paper presents the vibration analysis of a robotic system, which performs ultrasonic welding of metal tabs on rechargeable batteries commonly used for hybrid or electric vehicles. A robotic battery-welding cell was set up, battery tab welding was performed and the vibration data was collected by using accelerometers and LVDT sensors. The data was(More)
Conveyor based transportation systems are used in today manufacturing environments. The main concept we introduce in this paper is using mobile platforms to move parts, tools and fixtures between workstations in a manufacturing environment instead of conveyors. A conveyor-based production system is a fixed transportation system, hard mounted and not(More)
This paper presents the overview and the introduction of commercialized robotic products in the industrial service, maintenance and repair sectors. General facts of the industrial service are briefly described, and then we focus on four specific applications including motor /generator inspection, solar panel inspection /cleaning, tank inspection and pipe(More)
Many tasks in the meat processing industry involve repetitive and physically demanding work. Therefore, the workers are highly susceptible to repetitive-strain injuries to their hands, wrists, elbows, and back. Additionally, quality control and hygiene requirements are vital to this industry. For these reasons, industrial robots have been considered for(More)
This paper presents a lead-through method and device for industrial robots and more particularly the design and calibration of a portable lead-through teaching device. Most industrial robots are programmed by a teach-and-playback approach. In some applications, maneuvering robots using the joystick or keypad on the teach pendant along the desired path is(More)
We present an industrial robotic system that demonstrates the capability to perform the ultrasonic welding of metal tabs on battery cells on the electric vehicles. We investigate the robotic ultrasonic welding by performing robotic welding of the battery module tab of general or/and specific configuration, collecting and analyzing vibration data at various(More)