• Journal of the Korean Society for Precision Engineering
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• v.26 no.10
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• pp.32-39
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• 2009

Most mobile devices provide limited input interfaces in order to maximize the mobility and the portability. In this paper, the author proposes a small cubic-shaped tangible input interface which tracks the location, the direction, and the velocity using MEMS sensor technology to overcome the physical limitations of the poor input devices in mobile computing environments. As the preliminary phase for implementing the proposed tangible input interface, the prototype design and implementation methods are described in this paper. Various experiments such as menu manipulation, 3-dimensional contents control, and sensor data visualization have been performed in order to verify the validity of the proposed interface. The proposed tangible device enables direct and intuitive manipulation. It is obvious that the mobile computing will be more widespread and various kinds of new contents will emerge in near future. The proposed interface can be successfully employed for the new contents services that cannot be easily implemented because of the limitation of current input devices. It is also obvious that this kind of interface will be a critical component for future mobile communication environments. The proposed tangible interface will be further improved to be applied to various contents manipulation including 2D/3D games.

• Proceedings of the Korea Society of Design Studies Conference
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• 2003.05a
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• pp.22-23
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• 2003

• Journal of the HCI Society of Korea
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• v.12 no.4
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• pp.37-44
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• 2017

Eye-typing is one kind of human-computer interactive input system which is implemented by location data of gaze. It is widely used as an input system for paralytics because it does not require physical motions other than the eye movement. However, eye-typing interface based on Korean character has not been suggested yet. Thus, this research aims to implement the eye-typing interface optimized for Korean. To begin with, design objectives were established based on the features of eye-typing: significant noise and Midas touch problem. Multilevel input system was introduced to deal with noise, and an area free from input button was applied to solve Midas touch problem. Then, two types of eye-typing interfaces were suggested on phonological consideration of Korean where each syllable is generated from combination of several phonemes. Named as consonant-vowel integrated interface and separated interface, the two interfaces are designed to input Korean in phases through grouped phonemes. Finally, evaluation procedures composed of comparative experiments against the conventional Double-Korean keyboard interface, and analysis on flow of gaze were conducted. As a result, newly designed interfaces showed potential to be applied as practical tools for eye-typing.

• Journal of Korean Institute of Industrial Engineers
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• v.28 no.2
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• pp.193-200
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• 2002

A study was conducted to investigate the availability of Fitts' Law to Hangul input systems on mobile phones. Three different Hangul input systems were experimented to measure the performance time to evaluate the physical interface of all. The measured performance time was found to be well fitted with the modified Fitts' Law by Hangul input systems on mobile phones. As a result, the physical interfaces for Hangul input systems could be evaluated quantitatively with the prediction of the performance time by Fitts' Law.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.5
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• pp.86-93
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• 1997

With recent development of speech recognition technology and multimedia computer systems, more potential applications of voice will become a reality. In this paper, we implement speech interface on the windows95 environment for practical use fo multimedia computers with voice. Speech interface is made up of three modules, that is, speech input and detection module, speech recognition module, and application module. The speech input and etection module handles th elow-level audio service of win32 API to input speech data on real time. The recognition module processes the incoming speech data, and then recognizes the spoken command. DTW pattern matching method is used for speech recognition. The application module executes the voice command properly on PC. Each module of the speech interface is designed and examined on windows95 environments. Implemented speech interface and experimental results are explained and discussed.

• Journal of Power Electronics
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• v.15 no.4
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• pp.1131-1138
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• 2015

This study presents an input-powered high-efficiency interface circuit for energy harvesting systems, and introduces a zero standby power design to reduce power consumption significantly while removing the external power supply. This interface circuit is composed of two stages. The first stage voltage doubler uses a positive feedback control loop to improve considerably the conversion speed and efficiency, and boost the output voltage. The second stage active diode adopts a common-grid operational amplifier (op-amp) to remove the influence of offset voltage in the traditional comparator, which eliminates leakage current and broadens bandwidth with low power consumption. The system supplies itself with the harvested energy, which enables it to enter the zero standby mode near the zero crossing points of the input current. Thereafter, high system efficiency and stability are achieved, which saves power consumption. The validity and feasibility of this design is verified by the simulation results based on the 65 nm CMOS process. The minimum input voltage is down to 0.3 V, the maximum voltage efficiency is 99.6% with a DC output current of 75.6 μA, the maximum power efficiency is 98.2% with a DC output current of 40.4 μA, and the maximum output power is 60.48 μW. The power loss of the entire interface circuit is only 18.65 μW, among which, the op-amp consumes only 2.65 μW.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.247-249
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• 2007

This paper proposes a dry-type surface myoelectric sensor for the myoelectric hand prosthesis. The designed surface myoelectric sensor is composed of skin interface and processing circuits. The skin interface has one reference and two input electrodes, and the reference electrode is located in the center of two input electrodes. Considering the conduction velocity and the median frequency of the myoelectric signal, the inter-electrode distance (IED) between two input electrodes as 18mm, 20mm, and 22mm is selected. The signal processing circuit consists of a differential amplifier with a band pass filter, a band rejection filter for rejecting 60㎐ power-line noise, amplifier, and a level circuit. Using SUS440, six prototype skin interface with different reference electrode shape and IED is fabricated, and their output characteristics are evaluated by output signal obtained from the forearm of a healthy subject. The experimental results show that the skin interface with parallel bar shape and the 18mm IED has a good output characteristics. The fabricated dry-type surface myoelectric sensor is evaluated for the upper-limb amputee.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.12
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• pp.550-557
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• 2006

This paper proposes a dry-type surface myoelectric sensor for the myoelectric hand prosthesis. The designed surface myoelectric sensor is composed of skin interface and processing circuits. The skin interface has one reference and two input electrodes, and the reference electrode is located in the center of two input electrodes. In this paper is proposed two types of sensors with the circle- and bar-shaped reference electrode, but all input electrodes are the bar-shaped. The metal material of the electrodes is the stainless steel (SUS440) that endures sweat and wet conditions. Considering the conduction velocity and the median frequency of the myoelectric signal, the inter-electrode distance (IED) between two input electrodes as 18mm, 20mm, and 22mm is selected. The signal processing circuit consists of a differential amplifier with a band pass filter, a band rejection filter for rejecting 60Hz power-line noise, amplifiers, and a mean absolute value(MAV) circuit. Using SUS440, six prototype skin interface with different reference electrode shape and IED is fabricated, and their output characteristics are evaluated by output signal obtained from the forearm of a healthy subject. The experimental results show that the skin interface with parallel bar shape and the 18mm IED has a good output characteristics. The fabricated dry-type surface myoelectric sensor is evaluated for the upper-limb amputee.

• The Journal of Korean Association of Computer Education
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• v.12 no.6
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• pp.69-79
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• 2009

The current user interface (UI) of NEIS school affairs business system is not efficient in conducting the business because of complicated data input forms as well as unharmonious connection between similar items and functional menu. In the paper, the term UI means a comprehensive concept including input/output, input/output related functionality, and menu configuration for users to perform their tasks. The first survey, carried out with one hundred teachers at three elementary schools of Kyeonggi-do, shows that the UI problems of the system are manual inputs, inconvenient menu configuration, disconnection between academic calendar and educational process, complexities of managing attendance report and curriculum evaluation, etc. We have improved the UI design by providing more efficient input method and more systematic menu configuration compared to the current system, and then evaluated the design through the second survey. Evaluation results show that users prefer the proposed UI design especially from the viewpoint of user-friendly input interface and user-oriented view composition.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.512-517
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• 2001

In this paper, a wide input range active multi-pulse rectifier for utility interface of power electronic converters is proposed. The scheme combines multi-pulse method using a V-A transformer and boost rectifier modules. A current control scheme for the rectifier modules is proposed to achieve sinusoidal line currents in the utility input over a wide input range of input voltage and output load conditions. A design example is included for a 208V to 460V input, $700V_{dc}$ do 10kW output rectifier system. Simulation results are shown.