• Journal of the Korean Society for Precision Engineering
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• v.23 no.7 s.184
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• pp.130-137
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• 2006

TFT-LCD(Thin Film Transistor Liquid Crystal Display) module is representative commercial product of FPD(Flat Panel Display). Thickness of TFT-LCD module is very thin. It is adopted for major display unit for IT devices such as Cellular Phone, Camcorder, Digital camera and etc. Due to the harsh user environment of mobile IT devices, it requires complicated structure and tight assembly. And user requirements for the mechanical functionalities of TFT-LCD module become more strict. However, TFT-LCD module is normally weak to high level transient mechanical shock. Since it uses thin crystallized panel. Therefore, anti-shock performance is classified as one of the most important design specifications. Traditionally, the product reliability against mechanical shock is confirmed by empirical method in the design-prototype-drop/impact test-redesign paradigm. The method is time-consuming and expensive process. It lacks scientific insight and quantitative evaluation. In this article, a systematic design evaluation of TFT-LCD module for mobile IT devices is presented with combinations of FEA and testing to support the optimal shock proof display design procedure.

• Journal of the Korean institute of surface engineering
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• v.44 no.5
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• pp.213-219
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• 2011

Recently aspheric lenses are widely used for superpricision optical instruments, such as cellular phone camera modules, digital cameras and optical communication modules. The aspherical lenses are processed using mold core under high temperature compressive forming pressure. It is imperative to develop superhard protective films for the life extension of lens forming mold core. Especially ta-C films with higher $sp^3$ fractions receive attentions for the life extension of lens forming mold and, in turn, the cost reduction of lenses due to their suprior high temperature stability, high hardness and smooth surfaces. In this study ta-C films were processed on WC mold as a function of substrate bias voltage using FVA (Filtered Vacuum Arc) method. The processed films were characterized by Raman spectroscopy and nano-indentation to investigate bonding nature and hardness, respectively. The film with maximun 87% of $sp^3$ fraction was obtained at the substrate bias voltage of -60 V, which was closest to ta-C film. ta-C films showed better high temperature stability by sustaining relatively high fraction of $sp^3$ bonding even after 2,000 glass lens forming applications.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.1048-1050
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• 2013

Mobile devices or smartphones are rapidly becoming the central computer and communication network device. Recently, smartphones are programmable and come with a growing set of cheap powerful embedded sensors, such as an accelerometer, digital compass, gyroscope, GPS, microphone, and camera. In this paper, we discuss the wireless gas sensing service architectural and develope the gas sensor monitoring services using smartphone and web server.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.9
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• pp.2173-2179
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• 2015

In digital era image processing has been utilized in a variety of media such as TV, camera and smart phone. Typically salt and pepper noise are generated by various causes during the analysis, identification, and processing of image data. Principal filters such as SMF, CWMF, and AMF have been used to remove these noise. But the existing filters fall short of edge preservation and noise elimination in high noise densities. Thus, a processing algorithm, on which the size of deformable mask varies depending on the noise density, is proposed to remove salt and pepper noise effectively in this study. The performance of the proposed method was evaluated compared with the existing methods using PSNR.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.8
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• pp.1495-1504
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• 2008

New license plates have been used since 2007. This paper proposes a new license plate extraction method using a gray labeling and a fuzzy reasoning method. First, the proposed method extracts the candidate plates by the gray labeling which is the enhanced version of a non-recursive flood-filling algorithm. By newly designed fuzzy inference system. fitness of each candidate plates are calculated. Finally, the area of the license plate in a image is extracted as a region of the candidate label which has the highest fitness. In the experiments, various license plate images took from indoor/outdoor parking lot, street, etc. by digital camera or cellular phone were used and the proposed extraction method was showed remarkable results of a 94 percent success.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.221-228
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• 2011

As construction works have become larger and more complex, improving productivity by introducing Information Technology (IT) is pursued and more effective construction management is needed in construction industry. In this circumstance, many different kinds of project management system is being introduced, and various IT technologies are applied such as Personal Digital Assistant (PDA), Bar Code, Radio Frequency Identification (RFID), Web Camera, and so on. However, these kinds of technologies might cause re-processing of information and ineffectiveness of project because of lack of real time information processing technology or separation between construction sites and management offices. Meanwhile, these technologies rather decrease the construction productivity except for the data saving and database function. Therefore, this research aims to develop Application that can be applied efficiently for construction material management, by understanding problems of former management system with questionnaires and extracting functions with analysis of requirements. In virtue of the construction material management Application which will be developed in this study, it will be possible to input information automatically, to process and check material information in real time, and to identify the location of necessary material. Then, the problem of separation between construction sites and management offices are solved, and as a result, more efficient management of materials in construction sites will become possible. At the same time, this study will investigate the possibility and applicability of new IT device, Smart Phone to construction sites.

• Transactions of the Society of Information Storage Systems
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• v.1 no.2
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• pp.115-120
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• 2005

As a popularity of a portable digital device such as a cellular phone, a digital camera and a MP3 player is spreading, the demand of the mobile storage device increases rapidly. A bluray technology using 405nm laser diode and objective lens having high NA(Numerical Aperture), 0.85, satisfies a miniaturization and a high capacity which are the requirements of the portable device. To develop SFFOP(small form factor optical pickup), it is prerequisite to minimize the number of optical components and establish evaluation and assembly method of micro optical pickup system as well as mass production method of micro optical component. To minimize optical elements of optical pickup, there have been many researches to use P-HOE(Polarized Holographic Optical Element) due to its extremely small size and versatile function. However, P-HOE is handled and assembled very accurately in SFFOP. In this paper, static error signal detection method is developed for an alignment of P-HOE in SFFOP. Using developed static error signal detection method, P-HOE can be aligned very accurately with real time result of static error signals of pickup such as FES(focusing error signal) and TES(Tracking Error Signal). The developed static error signal detection method is verified by the evaluation of commercialized DVD Pickup. And finally. developed static error signal detection method is applied for the assembly of P-HOE in SFFOP system satisfies specification of BD(Blu-ray Disk).

• Transactions of the Society of Information Storage Systems
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• v.5 no.2
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• pp.96-101
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• 2009

In recent years, the demand for portable digital devices such as cellular phone, digital camera, and MP3 player has been largely increased. To meet the requirements of such portable applications the information storage devices with smaller size, higher capacity, and lower power consumption are needed. A small form factor (SFF) HDD using a load/unload (L/UL) system is one of the appropriate alternatives to satisfy these requirements. Due to complexity of L/UL process and mechanism, it is required to investigate for better understanding the effects of design parameters. Among the various design parameters, flexible cable and friction force on the L/UL ramp become important to the dynamic characteristics of L/UL process as the system is miniaturized. The program for L/UL simulation which considers the effect of flexible cable and L/UL ramp is needed. Unfortunately, there is hardly any commercial program for the L/UL simulation except the Computer Mechanics Laboratory (CML) air bearing design program and the CML L/UL simulation code. Furthermore, the design parameters such as flexible cable and the L/UL ramp are not considered in the CML L/UL simulation code. So we embody the L/UL simulation considering flexible cable and an L/UL ramp by using the ANSYS/LS-DYNA. In this thesis, the effects of flexible cable and friction force on the dynamic characteristics and the performances of the L/UL process are studied. Numerical simulation and related experiments are carried out and compared each other.

• Journal of Digital Convergence
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• v.16 no.10
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• pp.213-222
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• 2018

This study was conducted to derive the traffic accident risk index through the recognition of the elderly driver's driving pattern to reduce the traffic accident rate of elderly drivers and to reflect them in the renewal and return policy of driver's license accordingly. First, the traffic accident risk index is defined by analyzing the behavioral characteristics of older drivers to derive the major factors that lead to traffic accidents. Second, we present a method to measure the traffic accident risk index from the driving pattern of the elderly through the smart-phone, the camera and the distance sensor attached to the car. Finally, we derive three thresholds by computer simulation and determine the accident risk from the measured traffic accident risk index as four steps and suggest ways to ensure safe driving of older drivers. It is required to objectively assess the driving ability of an aged driver in accordance with the proposed method, and to induce the driver to reset the driver's license renewal cycle and voluntarily return the driver's license to minimize social costs due to increased traffic accidents.

• The Journal of Society for e-Business Studies
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• v.22 no.1
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• pp.1-13
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• 2017

Though digital imaging devices such as smart phones, digital cameras and office scanners have improved significantly over the past years, they are seldom used for industrial application. This may be attributable to high level of quality and performance requirement for industrial application, but there lacks a test or an objective evaluation whether the upgraded performance of entry-level device is sufficiently enough to replace existing industrial equipments or not. If there exists an industrial application area where the applicability of entry-level equipment is proved by some objective tests, then companies will be able to reduce investment on expensive industrial equipment. In this study, applicability of entry-level digital devices for color difference discrimination of PVC (Polyvinyl chloride) color sheet is tested. By testing smart phone, digital camera, and office scanner for color difference discrimination, authors have found that office scanner shows consistent result with less measurement error. Additional experiment on comparing office scanner with industrial spectrophotometer has confirmed that there exists high correlation between the two devices' results. Based on this result, office scanner may be applicable to discriminate the color difference of PVC sheet instead of expensive industrial spectrophotometer if proper management criteria are established.