• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.280-281
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• 2009

Piezoelectric vibrators can be good replacements of electric motors to excite touch screen of a mobile device owing to small volume and low power consumption. One problem to be solved yet for real application is larger excitation force or moment than available currently. More efficient excitation by a piezoelectric vibrator could be achieved by operating at one of resonance frequencies of the system, which must also be as close as possible to frequency range where index finger is most sensitive and increasing transmission force or moment at that frequency. In this study, dynamic models are derived for the piezoelectric exciter and an adhesive viscoelastic layer, which connect the exciter to the screen. The adhesive layer is modeled as distributed stiffness by considering its geometric shape to relative to the piezoelectric exciter. Then, equations of motion for the piezoelectric exciter and the adhesive layer are derived using Hamilton's principle. Based on this model, dynamic characteristics of the exciter will be designed to maximize the force or moment transmitted onto the screen structure.

• Journal of the Korea Society of Computer and Information
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• v.19 no.9
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• pp.39-44
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• 2014

In this paper, we study the light pen emulator implementation that can be used in industrial computer. For use in industrial control field, an input device of an industrial machine is an electronic pen is usually used, but now many cases, a light pen cannot be used to the computer. In this study, the light pen emulator to substitute for the function that is available to the peripheral device on the PC, now. So we want to increase the utilization of industrial computer in this research. The light pen emulator was designed by USB HOST, CPLD and MPU. Light pen signal, after interpret the input from the touch screen and mouse and USB system data, was output by calculating screen coordinates. As a result, we showed that it is possible to use the computer in a variety of industrial devices such as a mouse, digitizer, touch screen, stylus, and designed emulator.

• Journal of the HCI Society of Korea
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• v.11 no.1
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• pp.11-19
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• 2016

This study aimed to assess the economic value of the UX design and applied contingent valuation method (CVM) to the three smartphone screen unlock interface types: touch, fingerprint, and iris recognition. The contingent valuation method was chosen from various economic valuation approaches because the interface components such as the screen unlock are important user experience values but non-market goods which are not traded independently. Using the double-bounded dichotomous choice approach of the contingent valuation method, the survey results of the logit model showed that the economic value of touch unlock interface was 529 won, fingerprint was 4,214 won, and iris recognition was 1,316 won. That is, the fingerprint interface had the highest economic value, followed by iris recognition and touch interface. The main contribution of this research is that we examined a method for economic valuation of the UX design and generated systematic and credible results.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1519-1522
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• 2009

We describe a 32" liquid-crystal display (LCD) with multi-touch sensing capability by integrating IR detector arrays onto the LED backlight plate. A transparent light guide is placed in front of the display screen, with IR LEDs disposed at its edges and emitting IR light into the light guide, the light is trapped by total internal reflection within the light guide to be as touch-sensing light. A physical contact with the acrylic plate surface will stimulate some trapped light to be escaped from the light guide and pass through LCD panel to be detected by the IR detectors. The touch-sensing LCD with this configuration can locate simultaneous multiple touche points on the touchable surface.

• Journal of Industrial Technology
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• v.30 no.A
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• pp.25-29
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• 2010

In this paper, we implement a multi-touch system using FIDR. The implementation consists of hardware manufacture and development of image processing system. In the hardware system, touch screen, infrared LED placements and infrared camera are made. The image processing procedure is to extract each pointer's coordinates from image data and includes binary-coding, noise-elimination, labeling and calculation of mass center. From the implementation, we are able to make a multi-touch system with considerably lower cost than the existing ones.

• Journal of the HCI Society of Korea
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• v.7 no.2
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• pp.49-56
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• 2012

The camera-based mobile applications such as color, pattern and object reading can improve the living quality of blind people. However currently available camera-based applications are uncomfortable for the blind, since these applications do not reflect accessibility requirements of the blind especially on touch screen. We investigated accessibility requirements about rapidly growing camera-based mobile applications on touch screen devices for the blind. In order to identify accessibility requirements, we conducted a usability testing for color reading applications with three different types of interfaces on Android OS. The results of the usability testing were as follows: (1) users preferred short depth of menu hierarchy, (2) the initial audio help was more useful than just-in-time help, (3) users needed both manual and automatic camera shooting modes although they preferred manual to automatic mode, (4) users wanted the OS supported screen reader function to be turned off during the color reading application was running, and (5) users required tactile feedback to identify touch screen boundary. We designed a new user interface for blind people by applying the identified accessibility requirements. From a usability testing of the new user interface with 10 blind people, we showed that the identified accessibility requirements were very useful accessibility guidelines for camera-based mobile applications.

• Journal of Convergence for Information Technology
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• v.7 no.4
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• pp.75-81
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• 2017

The design trend of information technology is quickly changed with the times. The design trend of information display is a bezel-less display, recently. The bezel-less display or edge-less display is a new trend of mobile phone display. In this study, the shading tape was manufactured for assembling process of touch panel display with the high screen-to-body ratio so-called bezel-less display. The shading tape was fabricated on PET film with the UV curable acrylic pressure sensitive adhesive(PSA) by roll-to-roll process. The UV curable PSA was synthesized with the eco-friendly toluene-less manufacturing method. The adhesive power of manufactured shading tape was investigated by motorized tensile testing machine. The thixotropic, maintaining property of cutting shape, was characterized by field emission scanning electron microscope. As results, the shading tape exhibits high adhesive power and good thixotropic performance suitable for assembly process of touch panel display. The functional shading tape will be expected to improve productivity of assembly process of touch panel display.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.5
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• pp.423-432
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• 2023

With the increasing demand for mobile devices featuring multi-touch operation, extensive research is being conducted on touch screen panel (TSP) Readout ICs (ROICs) that should possess low power consumption, compact chip size, and immunity to external noise. Therefore, this paper discusses capacitive touch sensors and their readout circuits, and it introduces research trends in various circuit designs that are robust against external noise sources. The recent state-of-the-art TSP ROICs have primarily focused on minimizing the impact of parasitic capacitance (Cp) caused by thin panel thickness. The large Cp can be effectively compensated using an area-efficient current compensator and Current Conveyor (CC), while a display noise reduction scheme utilizing a noise-antenna (NA) electrode significantly improves the signal-to-noise ratio (SNR). Based on these achievements, it is expected that future TSP ROICs will be capable of stable operation with thinner and flexible Touch Screen Panels (TSPs).

• Journal of Korean Institute of Industrial Engineers
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• v.41 no.3
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• pp.225-232
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• 2015

The smart watch is the most popular wearable computing device because it takes a form of wristwatch. Many smart watches have adopted the touch screen interface due to the limited size of display. This paper focuses on touch key size and spacing that affect the usability about the touch key of smart watch. The experiments were made for four touch key sizes (width${\times}$height; $5{\times}5$, $5{\times}7$, $7{\times}5$, $7{\times}7mm$) and nine touch key spacing (vertical${\times}$horizontal; $0{\times}0$, $0{\times}1$, $0{\times}3$, $1{\times}0$, $1{\times}1$, $1{\times}3$, $3{\times}0$, $3{\times}1$, $3{\times}3mm$). The completion time, error rate, control discomfort and identification discomfort were measured. The touch key size $7{\times}7$, $7{\times}5$ and the touch key spacing $3{\times}3$, $1{\times}3$ provided the best results in terms of the completion time and the control discomfort, while the square touch key ($7{\times}7$, $5{\times}5$) provided the best performance for the error rate measure. The result of this study can help ergonomically design the touch interface of the smart watch.

• IEIE Transactions on Smart Processing and Computing
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• v.3 no.4
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• pp.226-233
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• 2014

This paper presents an external light evasion method that rectifies the problem of misrecognition due to external lighting. The fundamental concept underlying the proposed method involves recognition of the differences between two images and elimination of the desynchronized external light by synchronizing the image sensor and inner light source of the optical touch screen. A range of artificial indoor light sources and natural sunlight are assessed. The proposed system synchronizes with a Vertical Synchronization (VSYNC) signal and the light source drive signal of the image sensor. Therefore, it can display synchronized light of the acquired image through the image sensor and remove external light that is not from the light source. A subtraction operation is used to find the differences and the absolute value of the result is utilized; hence, the order is irrelevant. The resulting image, which displays only a touched blob on the touchscreen, was created after image processing for coordination recognition and was then supplied to a coordination extraction algorithm.