• Journal of Sensor Science and Technology
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• v.29 no.6
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• pp.394-398
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• 2020

In this paper, we report the sensing performance of H₂ gas sensors composed of Pd/carbon nanotube (CNT) buckypaper at room temperature. The CNT buckypaper was made using a simple filtration process and subsequently deposited with Pd as the sensing material. The sensitivity of the sensor increased with respect to the gas concentration. To investigate the effect of Pd thickness, Pd layers of different thickness were deposited on the buckypaper, and the response of the sensor was evaluated. The proposed sensor exhibits excellent sensing properties with optimized Pd thickness at room temperature (25℃). Pd nanoparticles significantly impact the sensitivity and selectivity of the sensor because of the spillover effect. In addition, the sensor is highly suitable for bendable and wearable devices owing to its structural flexibility.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.05a
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• pp.159-160
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• 2019

It would be very important to localize people at risk as soon as possible in order to minimize the damage. Generally the infrastructure should be deployed additionally for indoor positioning system. In this paper, we proposed an indoor localization system for people at risk using the existing fire alarm networks. The system detects the signal of smart devices of people in danger immediately and let the main alarm controller ring all alarms in vessel and display the position. Thus, the proposed system can make the burden much less to deploy additional network and infrastructure.

• Journal of the Korean Applied Science and Technology
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• v.34 no.2
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• pp.280-288
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• 2017

Nanocarbon base materials such as, graphene and graphene hybrid with high electrochemical performances have great deal of attention to investigate flexible, stretchable display and wearable electronics in order to develop portable and high efficient energy storage devices. Battery, fuel cell and supercapacitor are able to achieve those properties for flexible, stretchable and wearable electronics, especially the supercapacitor is a promise energy storage device due to their remarkable properties including high power and energy density, environment friendly, fast charge-discharge and high stability. In this study, we have fabricated flexible supercapacitor composed of graphene/conductive polymer composite which could improve its electrochemical performance. As a result, specific capacitance value of the flexible supercapacitor (unbent) was $198.5F\;g^{-1}$ which decreased to $128.3F\;g^{-1}$ (65% retention) after $500^{th}$ bending cycle.

• Journal of the HCI Society of Korea
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• v.6 no.1
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• pp.1-8
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• 2011

As virtual realty has become an issue of providing immersive services, in the area of virtual realty, it has been actively investigated to develop user interfaces for immersive interaction. In this paper, we propose a gesture recognition based immersive user interface by using an IR LED embedded helmet and data gloves in order to reflect the user's movements to the virtual reality environments effectively. The system recognizes the user's head movements by using the IR LED embedded helmet and IR signal transmitter, and the hand gestures with the data gathered from data gloves. In case of hand gestures recognition, it is difficult to recognize accurately with the general recognition model because there are various hand gestures since human hands consist of many articulations and users have different hand sizes and hand movements. In this paper, we applied the Mixture-of-Experts based gesture recognition for various hand gestures of multiple users accurately. The movement of the user's head is used to change the perspection in the virtual environment matching to the movement in the real world, and the gesture of the user's hand can be used as inputs in the virtual environment. A head mounted display (HMD) can be used with the proposed system to make the user absorbed in the virtual environment. In order to evaluate the usefulness of the proposed interface, we developed an interface for the virtual orchestra environment. The experiment verified that the user can use the system easily and intuituvely with being entertained.

• Journal of IKEEE
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• v.24 no.3
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• pp.859-866
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• 2020

This paper proposes a 2-ch DC-DC converter with a wide-input voltage range from 2.9V~5.6V for wearable AMOLED displays. For positive voltage V_POS, a boost converter is designed using an over-charged voltage permissible circuit (OPC) which generates a normal output voltage even if over-input voltage is applied, and a SPWM-PWM dual mode with 3-segmented power transistors to improve efficiency at light load. For negative voltage V_NEG, a 0.5x regulated inverting charge pump is designed to increase power efficiency. The proposed DC-DC converter was designed using a 0.18-㎛ BCDMOS process. Simulation results show that the proposed DC-DC converter generates V_POS voltages of 4.6 V and V_NEG voltage of -0.6V~-2.3V for input voltage of 2.9V to 5.6V. In addition, it has power efficiency of 49%~92%, output ripple voltage has less than 20 mV for load current range of 1 mA~70 mA.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.52-56
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• 2006

선천적인 원인으로 인해 언어 장애를 겪고 있는 사람들이나 후두암 등 후천적 질환이 원인이 되어 의사 소통에 불편을 겪는 사람들이 있다. 본 논문에서 제안하는 '손으로 말해요'는 이러한 사람들의 의사 표현을 돕기 위한 장치이다. 뇌에 손상이 있거나 성대에 손상이 있어 말하는 것이 어려운 장애인들이 장갑모양의 입력장치와 목 부위에 부착된 스피커를 이용해 말할 수 있다. 이 스피커를 통해 흘러나오는 인공의 목소리로 의사 소통할 수 있다. 언어장애인을 위한 본 웨어러블 PC 의 특징은 먼저 블루투스 모듈을 이용한 간단한 손가락 동작만으로도 입력이 가능한 장갑 모양의 입력장치이다. 사용이 불편한 엄지 손가락을 제외한 나머지 네 손가락에 각 하나씩 양손 총 8 개의 스위치가 부착되어 있다. 사용자는 손가락을 굽혀 손바닥에 스위치가 닿도록 하거나 책상 등과 같이 편평한 탁자에 손가락 끝을 닿게 하여 스위치를 누를 수 있다. 장갑의 키 배열은 PC 키보드의 배열과 같아 사용자가 쉽게 적응할 수 있다. 다음으로 본 장치는 자연스러운 목소리가 흘러나오는 음성 합성 모듈을 탑재하였다. 모듈의 출력 음성은 실제 말하는 것과 같은 자연스러운 억양을 지니고 있으며, 스피커는 목소리가 흘러나오는 위치가 자연스럽도록 목 부위에 부착되어 있다. 그리고 HMD(Head Mounted Display)를 탑재하여 자신이 텍스트를 정확하게 입력하고 있는지 이를 통해 확인할 수 있다. 장갑을 제외한 모든 장비는 가방에 탑재하여 착용이 편리하도록 하였고, 장갑은 블루투스 모듈을 이용하여 이용에 불편을 주는 전선을 제거하였다. 본 논문에서 제안하는 '손으로 말해요'는 간단한 손가락 동작을 이용하여 자연스러운 목소리로 말하고자 하는 내용을 전달할 수 있기 때문에 언어장애로 불편함을 겪는 사람들에게 도움을 줄 수 있다.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.13-18
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• 2008

In these days, wearable and mobile physiological sensing devices have been studied according to the increasing interest on the healthy and wellbeing life. However, these sensing devices display just the sensing results, such as heart rate, skin temperature, and its daily records. In this work, we propose the novel type of mobile physiological sensing device which deliver the user comfortable grabbing feeling. In addition, we indicate the personalized physiological signal analysis result which be concluded by the different analysis results according to the person to person. In order to verify this sensing device, we collect the data set from 4 different users during a week and measure the physiological signal such as heart rate, hand temperature, and skin conductance. And we observe the result how the analysis results shows the difference between the users. We expect that this work can be applied in the various health care applications in the near future.

• 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.

• Design & Manufacturing
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• v.11 no.1
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• pp.1-6
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• 2017

In these days, due to generalization of using smart mobile phone and wearable device such as smart watch, demand of Cover-glass and touch screen panel for protecting display increases. With increasing the demand of Cover-glass, slimming technique is promising for weight lightening, zero bezel. Cover-glass produced by this technique is required to decreasing thickness with increase strength. In the Cover-glass manufacturing process, mechanical processing and chemical processing has improve in the strength. Generally, Diamond electrodeposition wheel is used in mechanical process. Reinforced glass with the characteristics of the brittle and high hardness was manufactured by using a diamond electrodeposition wheel. At this time, Because of surface of the tool present non-uniform distribution of diamond particle, it has generate Loading of wheel and it has been decrease life of grinding tool, efficiency of grinding, quality and shape accuracy of workpiece. Thus Research is needed to controling particle distribution of diamond electrodeposition wheel uniformly. And it is necessary to study micro hole machining such as proximity senser hole, speaker hole positioned Cover-glass. Reinforced glass with the characteristics of the brittle and high hardness is difficult to machining. Processing of reinforced glass have generated wear of tool, micro cracks. Also, it is decreasing shape accuracy. In this paper, We conducted a study on how to control particle distribution uniformly about the diamond tool manufactured using elecetodeposition processing. It analyzed the factors that affect the arrangement of the particles in the electrodeposition process by design of experiment. And There is produced the grinding tool, which derives an optimum deposition conditions, for processing Cover-glass edge and the machinability was evaluated.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.2
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• pp.167-173
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• 2015

Extraction of Finger-end points is one of the most process for user multi-commands in the Hand-Gesture interface technology. However, most of previous works use the geometric and morphological method for extracting a finger-end points. Therefore, this paper proposes the method of user finger-end points extraction that is motivated a ultrared diffused illumination, which is used for the user commands in the multi-touch display device. Proposed air-mouse is worked by the quantity state and moving direction of extracted finger-end points. Also, our system includes a basic mouse event, as well as the continuous command function for expending a user multi-gesture. In order to evaluate the performance of the our proposed method, after applying to the web browser application as a command device. As a result, the proposed method showed the average 90% success-rate for the various user-commands.