• Journal of KIISE
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• v.44 no.9
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• pp.887-892
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• 2017

Brain-computer interface (BCI) is a technology that controls computer and transmits intention by measuring and analyzing electroencephalogram (EEG) signals generated in multi-channel during mental work. At this time, optimal EEG channel selection is necessary not only for convenience and speed of BCI but also for improvement in accuracy. The optimal channel is obtained by removing duplicate(redundant) channels or noisy channels. This paper propose a dual filter-based channel selection method to select the optimal EEG channel. The proposed method first removes duplicate channels using Spearman's rank correlation to eliminate redundancy between channels. Then, using F score, the relevance between channels and class labels is obtained, and only the top m channels are then selected. The proposed method can provide good classification accuracy by using features obtained from channels that are associated with class labels and have no duplicates. The proposed channel selection method greatly reduces the number of channels required while improving the average classification accuracy.

• The Journal of the Acoustical Society of Korea
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• v.36 no.2
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• pp.130-135
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• 2017

In this paper, we propose an interface for interactive sound experience in the virtual concert hall. The proposed interface consists of two systems, called 'virtual acoustic position' and 'virtual active listening'. To provide these systems, we applied an artificial reverberation algorithm, multi-channel source separation and head-related transfer function. The proposed interface was implemented by using Unity. The interface provides the virtual concert hall to user through Oculus Rift, one of the virtual reality headsets. Moreover, we used Leap Motion as a control device to allow a user experience the system with free-hand. And user can experience the sound of the system through headphones.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.569-572
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• 2003

The broadband wireless access industry, which provides high-tate network connections to stationary sites, has matured to the point at which it now has a standard for second-generation wireless metropolitan area networks. IEEE Standard 802.16, with its WirelessMAN air interface, set the stage for widespread and effective deployments worldwide. This paper presents an implementation of media access control that can be applied to BWA (Broadband Wireless Access) system. Medium access control (MAC) is a key issue in multi-access networks where a common channel is shared by many users. The designed MAC prototype roughly consists of MAC Hardware and MAC Software. The MAC Hardware part includes timing process, MAC transmission control, MAC reception control, and CRC/HCS process. The MAC Software part includes control of MAC signaling, network interface, and Physical (PHY) control. The designed MAC protocol will be integrated with the PHY of BWA in future and we can test overall system performance of MAC and PHY.

• Korean Institute of Interior Design Journal
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• v.14 no.3 s.50
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• pp.234-242
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• 2005

Interface is a medium or channel to communicate between human and things, while interaction is the manner of communication between them. Interaction design is designing experience of user through the interaction process for human, thing, system, and space. Richard Buchanan suggests four kinds of interaction: interface (person to thing interaction), transaction (person to person interaction), human interaction (human and environment interaction) and participation (human to cosmos interaction). With digital technology, architecture and space design have made various experiments at form, function, and content of space. Space evolves from a physical container to a stage to provide narrative and create new experience to users. Since understanding users, creating experience, efficient space design, content planning, and applicable technology are required for interaction design in space, multi-disciplinary research and cooperation is needed.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.515-518
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• 2003

The electrical current generated by heart creates not only electric potential but also a magnetic field. In this paper, we have designed the multiplexing data acquisition system for multichannel bio-magnetic signal measurement. The system consists of VXI rack which is organized MUX and AD board, Industrial rack which is mounted single board computer and DSP board. This system enable to realtime monitoring of multichannel data simultaneously. The number of channel could be increased simply added each module and firmware could be upgraded easily using host port interface of DSP.

• Proceedings of the KIEE Conference
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• 2008.04a
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• pp.163-165
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• 2008

In this paper we compare performance of exponential effective SINR mapping (EESM) with traditional actual value interface (AVI) approach for various modulation and coding schemes (MCS) in terms of coded bit error rate (BER) or block error rate (BLER) using different transmission schemes. This paper provides explanation and comparison of the two algorithms for single input single output (SISO), and single input multi-output (SIMO, 1X2) in OFDM systems. We calibrate the value of beta ($\beta$) in EESM using large number of channel realizations, here $\beta$ is a calibration constant. This paper also presents importance of beta value in EESM and how it improves the performance of OFDM wireless systems. We propose different modulation and coding schemes. Here we consider Standford university interim (SUI) channel models. Furthermore this paper also shows the detail observation of the two algorithms. Finally the conclusion review given for short summary.

• Proceedings of the IEEK Conference
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• 2002.06b
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• pp.165-168
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• 2002

As the demand for higher data-rate chip-to-chip communication such as memory-to-controller, processor-to-processor increases, low cost high-speed serial links\ulcorner become more attractive. This paper describes a 0.25-fm CMOS 1.6Gbps/pin 4-level transceiver using Stub Series Terminated Logic for high Bandwidth. For multi-gigabit/second application, the data rate is limited by Inter-Symbol Interference (ISI) caused by channel low pass effects, process-limited on-chip clock frequency, and serial link distance. The proposed transceiver uses multi-level signaling (4-level Pulse Amplitude Modulation) using push-pull type, double data rate and flash sampling. To reduce Process-Voltage-Temperature Variation and ISI including data dependency skew, the proposed high-speed calibration circuits with voltage swing controller, data linearity controller and slew rate controller maintains desirable output waveform and makes less sensitive output. In order to detect successfully the transmitted 1.6Gbps/pin 4-level data, the receiver is designed as simultaneous type with a kick - back noise-isolated reference voltage line structure and a 3-stage Gate-Isolated sense amplifier. The transceiver, which was fabricated using a 0.25 fm CMOS process, performs data rate of 1.6 ~ 2.0 Gbps/pin with a 400MHB internal clock, Stub Series Terminated Logic ever in 2.25 ~ 2.75V supply voltage. and occupied 500 * 6001m of area.

• The Journal of Korea Robotics Society
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• v.12 no.3
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• pp.270-278
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• 2017

The electrical muscle stimulator (EMS) based human machine interface (HMI) free to mechanical constraint and muscle fatigue problems are proposed for force feedback in a virtual reality. The device was designed to provide force feedback up to 4.8 N and 2.6 N each to the thumb and forefingers. The main objective of the HMI is to make unnecessary mechanical structures to attach on the hand or fingers. It employs custom EMSs and an interface arranged in the forearm. In this work, major muscle groups such as extensor pollicis brevis (EPB), extensor indicis proprius (EIP), flexor pollicis longus (FPL) and flexor digitorum profundus (FDP) are selected for efficient force feedback and controlled individually. For this, a human muscular-skeletal analysis was performed and verified. The validity of the proposed multi-channel EMS based HMI was evaluated thorough various experiments with ten human subjects, interacting with a virtual environment.

• 한국HCI학회:학술대회논문집
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• 2008.02b
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• pp.179-184
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• 2008

Changed TV, that has multi-channel and interactive attribute, requires viewer's activity. Also, broadcasting environment and TV user interface require same things equally. But, the viewer feels uncomfortable in current situation because they recognize the TV as passive media. especially, TV interface can't overcome limitation of TV media. And such interface is provided as it is. This problem brings viewer's confusion and dissatisfaction more and more. This study raises a question about viewer's activity and satisfaction, analyzes the relation and effect between activity and satisfaction.

• Journal of Magnetics
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• v.22 no.2
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• pp.214-219
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• 2017

Magnetic separators that clean the fluid stream from impurities, protect the installations in numerous industries. This paper introduces a graphical user interface (GUI) which proposes an optimized coil separating magnetic particles with a radius from 1 up to 500 µm. High gradient magnetic fields are employed in an arbitrary user defined fluidic channel which is made of a nonmetallic material. The effects of coil parameters are studied and adjusted to design an optimum coil with a minimum Ohmic loss. In addition, to design the coil scheme based on the particle movements, a mathematical particle-tracing model within the fluid channels has been utilized. In comparison to conventional magnetic separators, this model is reconfigurable by the user, produces a weaker magnetic field, allows for continuous purifying and is easy to install, with high separation efficiency. The presented GUI is simple to use, where the coil's manufacturing limitations can be specified.