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

• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.117.2-117
• /
• 2001

In this paper, 3D sound rendering using multichannel speakers is studied. Virtual 3D sound technology has mainly been researched with binaural system. The conventional binaural sound systems reproduce the desired sound at two arbitrary points using two speakers in 3DD space. However, it is hard to implement the localization of virtual source at back/front and top/below positions because the HRTF of an individual is unique just like the fingerprint. Most of all, the HRTF is highly sensitive to the elevation change. Multichannel sound systems have mainly been used to reproduce the sound field picked up over a certain volume rather than at specific points. Moreover, multichannel speakers arranged in 3-D space produce a much better performance of ...

• 한국초전도학회:학술대회논문집
• /
• v.11
• /
• pp.10-10
• /
• 2001

• The Journal of the Acoustical Society of Korea
• /
• v.31 no.5
• /
• pp.332-339
• /
• 2012

Beamspace transform algorithm transforms spatial-domain data - such as x, y, z dimension - into incidence-angle-domain data, which is called beamspace-domain data. The beamspace transform method is generally used in source localization and tracking, and adaptive beamforming problem. When the beamspace transform method is used in multichannel audio source separation, the inverse beamspace transform is also important because the source image have to be reconstructed. This paper studies the beamspace transform and inverse transform algorithms for multichannel audio source separation system, especially for the beamspace-domain multichannel NMF algorithm.

• Journal of Korea Multimedia Society
• /
• v.23 no.12
• /
• pp.1486-1495
• /
• 2020

The analysis of digital microscopy images plays a vital role in computer-aided diagnosis (CAD) and prognosis. The main purpose of this paper is to develop a machine learning technique to predict the histological grades in prostate biopsy. To perform a multiclass classification, an AI-based deep learning algorithm, a multichannel convolutional neural network (MCCNN) was developed by connecting layers with artificial neurons inspired by the human brain system. The histological grades that were used for the analysis are benign, grade 3, grade 4, and grade 5. The proposed approach aims to classify multiple patterns of images extracted from the whole slide image (WSI) of a prostate biopsy based on the Gleason grading system. The Multichannel Convolution Neural Network (MCCNN) model takes three input channels (Red, Green, and Blue) to extract the computational features from each channel and concatenate them for multiclass classification. Stain normalization was carried out for each histological grade to standardize the intensity and contrast level in the image. The proposed model has been trained, validated, and tested with the histopathological images and has achieved an average accuracy of 96.4%, 94.6%, and 95.1%, respectively.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.6 no.3
• /
• pp.131-139
• /
• 2010

Virtual reality(VR) technology allows users to experience the same sensation as if they look and feel real objects, and furthermore it enables users to experience phenomena in virtual environment which are difficult to illustrate in real world. A multichannel display is one of the virtual reality systems for generating high-quality images and guaranteeing a wide view angle using multiple projectors. In this work, we present the multichannel display system whose resolution is $4096{\times}1536$. We implement an automatic calibration (geometric and color) method for compensating the distorted image and color. The results clearly show the proposed system provides continuous and smooth images.

• Journal of Communications and Networks
• /
• v.16 no.2
• /
• pp.209-216
• /
• 2014

Cognitive radio (CR) has been proposed to solve the spectrum utilization problem by dynamically exploiting the unused spectrum. In CR networks, a spectrum selection scheme is an important process to efficiently exploit the spectrum holes, and an efficient channel allocation scheme must be designed to minimize interference to the primary network as well as to achieve better spectrum utilization. In this paper, we propose a multichannel selection algorithm that uses spectrum hole prediction to limit the interference to the primary network and to exploit channel characteristics in order to enhance channel utilization. The proposed scheme considers both the interference length and the channel capacity to limit the interference to primary users and to enhance system performance. By using the proposed scheme, channel utilization is improved whereas the system limits the collision rate of the CR packets.

• Journal of Biomedical Engineering Research
• /
• v.32 no.3
• /
• pp.207-217
• /
• 2011

Electrode impedances are measured to quantitatively characterize the electrode-electrolyte or cell-electrode interfaces. In the case of high-density microelectrode arrays(MEAs) that have been developed for brainmachine interface applications, the characterization process becomes a repeating and time-consuming task; a system that can perform the measurement and analysis in an automated fashion with accuracy and speed is required. However, due to the large number of channels, parasitic capacitance and off-capacitance components of the switching system become the major factors that decreased the accuracy for the measurement of high impedance microelectrodes. Here we investigated the implementation of automatic impedance measurement system with analyzing the causes of possible measurement-related problems in multichannel switching configuration. Based on our multi-channel measurement circuit model, we suggest solutions to the problems and introduce a novel impedance measurement scheme using electro-mechanical relays. The implemented measurement system could measure |Z| < 700 $k{\Omega}$ of impedance in - 10% errors, which can be widely applicable to high density neural recording MEAs.

• Korean Journal of Optics and Photonics
• /
• v.35 no.3
• /
• pp.107-114
• /
• 2024

In this study, the feasibility of using the covariance-matrix-adaptation-evolution-strategy (CMA-ES) algorithm in a multichannel coherent-beam-combining (CBC) system was experimentally verified. We constructed a multichannel CBC system utilizing a spatial light modulator (SLM) as a multichannel phase-modulator array, along with a coherent light source at 635 nm, implemented the stochastic-parallel-gradient-descent (SPGD) and CMA-ES algorithms on it, and compared their performances. In particular, we evaluated the characteristics of the CMA-ES and SPGD algorithms in the CBC system in both 16-channel rectangular and 19-channel honeycomb formats. The results of the evaluation showed that the performances of the two algorithms were similar on average, under the given conditions; However, it was verified that under the given conditions the CMA-ES algorithm was able to operate with more stable performance than the SPGD algorithm, as the former had less operational variation with the initial phase setting than the latter. It is emphasized that this study is the first proof-of-principle demonstration of the CMA-ES phase-control algorithm in a multichannel CBC system, to the best of our knowledge, and is expected to be useful for future experimental studies of the effects of additional channel-number increments, or external-phase-noise effects, in multichannel CBC systems based on the CMA-ES phase-control algorithm.

• 제어로봇시스템학회:학술대회논문집
• /
• 1990.10a
• /
• pp.580-585
• /
• 1990

This paper presents a real time FECG signal monitoring system in which an adaptive multichannel noise canceller is implemented using a Texas Instruments TMS32020 digital signal processor. Abdominal ECG signal is applied as the desired output and 3 chest ECG signals as the reference input signals of the adaptive multichannel noise canceller whose coefficients are updated using the LMS algorithms.