• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.1
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• pp.129-137
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• 2010

There are a lot of multimedia functions getting included in mobile devices recently, not only simple audio but visual functions as well, such as video playing, game and web browsing. Such the visual multimedia functions brought the strong requirement for much bigger LCD Display and high resolution. And the brightness of LCD is also one of major requirements and it is required to be more bright. However, LCD brightness is limited to increase because of power consumption. It occupies nearly 30% of the whole system power. This thesis suggests an effective and simple method of adjusting the LCD backlight brightness, considering a characteristic of battery and user pattern.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.451-454
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• 2009

There are a lot of multimedia functions getting included in mobile devices recently, not only simple audio but visual functions as well, such as video playing, game and web browsing. Such the visual multimedia functions brought the strong requirement for much bigger LCD Display and high resolution. And the brightness of LCD is also one of major requirements and it is required to be more bright However, LCD brightness is limited to increase because of power consumption. It occupies nearly 30% of the whole system power. This thesis suggests an effective and simple method of adjusting the LCD backlight brightness, considering a characteristic of battery and user pattern.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.1002-1005
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• 2015

Mobile operating systems have been typically classified into Apple and Android. Samsung showed its own new mobile OS developing Tizen based on Linux kernel. Mobile operating system has developed a technology using low-power by itself because of the limitation of capacity of battery, a feature of mobile. Samsung Tizen OS has a low-power technology called Power Manager controling LCD states as users'inputs or time-out events occur. However, if users'input occurs frequently, energy consumption jumped before-and-after users'input because CPU clock is increased rapidly due to overhead increase for frequent LCD state changes. This paper proposes a mechanism to reduce the overhead for LCD state changes, when user's input is frequent, by adding a new state to the Power Manager the current Tizen OS is using. We have implemented the proposed mechanism at Tizen phone kernel layer in this paper and experimented the mechanism according to users' LCD touch inputs. The experiment shows that it is possible to decrease energy by reducing the CPU clock increase according to the frequent user's inputs.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.754-757
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• 2007

This paper presents automatic LCD gamma control system using gamma curve optimization. It controls automatically gamma adjustment registers in mobile LCD driver IC to reduce average gamma error and adjusting time. The proposed gamma system contains module-under-test (MUT, LCD module), PC installed with program, multimedia display tester for measuring luminance, and control board for interface between PC and LCD module. We have developed a new algorithm using 6-point programmable matching technique with reference gamma curve. Developed algorithm and program are generally applicable for most of the LCD modules.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.592-595
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• 2008

This paper presents development of automatic image quality register optimization system using mobile TFT-LCD (Thin Film Transistor-Liquid Crystal Display) driver IC and embedded software. It optimizes automatically gamma adjustment and voltage setting registers in mobile TFT-LCD driver IC to improve gamma correction error, adjusting time, flicker noise and contrast ratio. Developed algorithms and embedded software are generally applicable for most of the TFT-LCD modules. The proposed optimization system contains module-under-test (MUT, TFT-LCD module), control program, multimedia display tester for measuring luminance, flicker noise and contrast ratio, and control board for interface between PC and TFT-LCD module. The control board is designed with DSP and FPGA, and it supports various interfaces such as RGB and CPU.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.3 s.309
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• pp.25-33
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• 2006

This paper proposed device-independent color matching algorithm based on the 3D RGB lookup table (LUT) between mobile camera and mobile LCD (Liquid Crystal Display) to improve the color-fidelity. Proposed algorithm is composed of thee steps, which is device characterization, gamut mapping, 3D RGB-LUT design. First, the characterization of mobile LCD is executed using the sigmoidal function, different from conventional method such as GOG (Gain Offset Gamma) and S-curve modeling, based on the observation of electro-optical transfer function of mobile LCD. Next, mobile camera characterization is conducted by fitting the digital value of GretagColor chart captured under the daylight environment (D65) and tristimulus values (CIELAB) using the polynomial regression. However, the CIELAB values estimated by polynomial regression exceed the maximum boundary of the CIELAB color space. Therefore, these values are corrected by linear compression of the lightness and chroma. Finally, gamut mapping is used to overcome the gamut difference between mobile camera and moible LCD. To implement the real-time processing, 3D RGB-LUT is designed based on the 3D RGB-LUT and its performance is evaluated and compared with conventional method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.540-543
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• 2007

In this paper, we propose a new approach to reduce the audible noise generated by TFT-LCD module in mobile applications. We also analyzed impact factors which effect on the audible noise. It is expected that this noise source comes from various impact factors such as vibration of flexible printed-circuit board (FPCB) and LCD panel, and static electricity charged in window and back-light unit. Windowless type and window type models are evaluated to analyze noise level due to the static electricity charged in window. To obtain reliable and reproducible data, we constructed controllable test jig and measurement set-up.

• 한국HCI학회:학술대회논문집
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• 2007.02b
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• pp.226-232
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• 2007

모바일폰의 LCD 전면화 추세로 인해 터치스크린을 기반으로 하는 모바일폰이 컨셉폰의 형태로 선보여지고 있고, 부분적으로 터치스크린을 차용한 모바일폰이 국내, 국외에 출시되고 있다. 터치스크린은 간편하고 직관적인 조작감을 제공하며 유동적인 인터페이스를 가능하게 하는 장점이 있다. 그리고 이러한 터치스크린의 장점을 적극적으로 활용할 수 있도록 하는 진보된 인터랙션 스타일도 다양하게 제안되고 있다. 하지만 기존의 터치스크린 기반의 모바일폰은 스타일러스를 그대로 사용하듯, 제한적이고 전형적인 인터렉션만을 제공하고 있고, 제안된 진보된 인터렉션 스타일들도 터치스크린 기반의 모바일폰에 직접적으로 활용하기는 어려운 실정이다. 본 연구는 진보된 인터랙션 스타일 중에서, 원 포인팅과 2개 이상의 포인팅이 가능한 멀티 포인팅 인터랙션을 연구하여 터치스크린기반의 Full LCD 모바일폰에 적합한 인터랙션 스타일을 제안한다. 이를 위해, 인터랙션에 대한 문헌연구와 함께 터치스크린을 기반으로 하는 다양한 디지털기기를 검토해보고, 터치스크린에 적용 가능한 진보된 인터랙션 사례들을 조사하였다. 그 후 터치디스크린 기반의 디지털기기를 사용하는 사용자의 행태를 파악하기 위한 유저테스트 및 인터뷰를 실시하여, 터치스크린 기반의 모바일폰에서 구현되어야 할 상세 인터랙션 스타일을 도출하였다. 본 연구에서 제안된 인터랙션 스타일은 다양한 사용자 경험을 가능하게 하여 고기능, 고사양화 되어가는 모바일폰의 UI를 보다 효과적으로 사용하는데 도움을 줄 것으로 기대된다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.734-737
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• 2008

This paper presents a new automatic TFT-LCD image quality optimization system. We also have developed new algorithms using 6-point programmable matching technique with reference gamma curve, and automatic power setting sequence. It optimizes automatically gamma adjustment and power setting registers in mobile TFT-LCD driver IC to reduce gamma correction error, adjusting time, and flicker. Developed algorithms and programs are generally applicable for most of the TFT-LCD modules. The proposed optimization system contains module-under-test (MUT, TFT-LCD module), control program, multimedia display tester for measuring luminance and flicker, and control board for interface between PC and TFT-LCD module. The control board is designed with DSP, and it supports various interfaces such as RGB and CPU. Developed automatic image quality optimization system showed significantly reduced gamma adjusting time, reduced flicker, and much less average gamma error than competing system. We believe that the proposed system is very useful to provide high image quality TFT-LCD and to reduce developing process time using optimized gamma-curve setting and automatic power setting.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.6B
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• pp.630-640
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• 2009

The thesis suggests hand-held equipment to overhaul for mobile TFT LCD/OLED module of high-performance. The established module equipment to overhaul could distinguish outputting video data to module for distinguishing flicker, but it is impossible with low system. In this thesis, supporting system could check the various supplement functions from bringing equipment to overhaul without changing design of FPGA or H/W the module various size for equipment to overhaul for module of high-performance coincidently. The system includes hand-held equipment to overhaul, test software embedded and software a base personal computer and have designed to output, save, and certify all contents of module test of hand-held equipment to overhaul to interface universal serial bus. Setting up 9 items that represent for efficient verification of the proposed system have been possible confirmation with TFT LCD/OLED module of high-performance, establishment scan time, creation gamma, changing register, supporting interface, and multi inch modules.