• 대한의용생체공학회:의공학회지
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• 제16권3호
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• pp.271-278
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• 1995

An ECG data compression algorithM using max-min slope update is proposed and a real time 3 channel ECG transmission system is implemented using the proposed algorithm. In order to effectively compress ECG data, we compare a threshold value with the max-min slope difference (MMSD) which is updated at each sample values. If this MMSD value is smaller than the threshold value, then the data is compressed. Conversely, when the MMSD value is larger than threshold value, the data is transmitted after storing the value and the length between the data which is beyond previous threshold level. As a result, it can accurately compress both the region of QRS, P, and T wave that has fast-changing and the region of the base line that slope is changing slow. Therefore, it Is possible to enhance the compression rate and the percent roms difference. In addition, because of the simplicity, this algorithm is more suitable for real-time implementation.

• 대한전기학회논문지:시스템및제어부문D
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• 제52권5호
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• pp.311-321
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• 2003

In an emergency telemedicine system such as the High-quality Multimedia based Real-time Emergency Telemedicine(HMRET) service, it is very important to examine the status of the patient continuously using the multimedia data including the biological signals(ECG, BP, Respiration, $SpO_2)$ of the patient. In order to transmit these data real time through the communication means which have the limited transmission capacity, it is also necessary to compress the biological data besides other multimedia data. For this purpose, we investigate and compare the ECG compression techniques in the time domain and in the wavelet transform domain, and present an effective lossless compression method of the biological signals using PEG Huffman table for an emergency telemedicine system. And, for the HMRET service, we developed the lossless compression and reconstruction program or the biological signals in MSVC++ 6.0 using DPCM method and JPEG Huffman table, and tested in an internet environment.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.513-516
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• 1999

I here are many kinds of method to compress data. To very simple methods from very complex methods, a kind is various. In this study, the simplest form of the Tolerance-Comparison method, zero-order method is used. Using this method, despite using low speed CPUs, it is possible to compress real time data. So this method is suitable for ECG holler system. In this study, to complement zero-order method, it is needed to develop prediction technique and to research ways to apply the technique.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권12호
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• pp.5855-5877
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• 2017

In view of personal health and disease management based on cost effective healthcare services, there is a growing need for real-time monitoring services. The electrocardiogram (ECG) signal is one of the most important of health information and real-time monitoring of the ECG can provide an efficient way to cope with emergency situations, as well as assist in everyday health care. In this system, it is essential to continuously collect and transmit large amount of ECG data within a given time and provide maximum user convenience at the same time. When considering limited wireless capacity and unstable channel conditions, appropriate signal processing and transmission techniques such as compression are required. However, ISO/IEEE 11073 standards for interoperability between personal health devices cannot properly support compressed data transmission. Therefore, in the present study, the problems for handling compressed data are specified and new extended agent and manager are proposed to address the problems while maintaining compatibility with existing devices. Extended devices have two PM-stores enabling compression and a novel transmission scheme. A variety of compression techniques can be applied; in this paper, discrete cosine transformation (DCT) is used. And the priority of information after DCT compression enables new transmission techniques for performance improvement. The performance of the compressed signal and the original uncompressed signal transmitted over the noisy channel are compared in terms of percent root mean square difference (PRD) using our simulation results. Our transmission scheme shows a better performance and complies with 11073 standards.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 D
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• pp.2727-2729
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• 2002

In an emergency telemedicine system such as High-quality Multimedia based Real-time Emergency Telemedicine(HMRET) service, it is very important to examine the status of the patient continuously using the multimedia data including the biological signals(ECG, BP, Respiration, $SpO_2$) of the patient. In order to transmit these data real time through the communication means which have the limited transmission capacity. It is also necessary to compress the biological data besides other multimedia data. For the HMRET service, we developed the lossless biological signal compression program in MSVC++ 6.0 using DPCM method and JPEG Huffman table, and tested in an internet environment.

• 전자공학회논문지SC
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• 제45권4호
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• pp.42-50
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• 2008

본 논문에서는 원격 의료 서비스를 위한 생체 신호 취득 및 전송 시스템의 실시간 신뢰성을 보장하기 위하여 ZigBee와 SIP/RTP를 기반으로 하는 실시간 생체 신호 전송 시스템의 성능 개선 방법을 제안하고 구현하였다. 기존의 시스템은 ZigBee기반의 유비쿼터스 센서 네트워크를 기반으로 사용자의 ECG 및 기타 생체 신호를 수집한다. 이 때 연속된 ECG 전송에 의하여 채널이 과다하게 점유되어 ECG 이외의 생체 신호를 전송할 때 패킷의 손실이 발생한다. 또한 하나의 RTP 세션을 통해 사용자의 음성과 ECG 및 기타 생체 신호를 순차적으로 전송하기 때문에 과중한 전송 스레드 부하와 지연이 발생한다. 따라서 본 논문에서는 ECG 전송 모듈의 채널 점유 문제를 해결하기 위해 Bluetooth를 보조 전송 수단으로 사용하고 복수의 RTP 세션과 전송 스레드를 사용하여 전송지연을 감소시키는 방법을 사용하였다. 또한 이산 웨이블릿 리프팅과 다단계 벡터 양자화 기반의 압축 방법을 적용하여 전송 및 저장되는 ECG를 압축하여 관리하는 구조를 제안하고 구현하였다. ECG의 압축은 데이터의 전송량을 감소시켜 시스템의 실시간 신뢰성을 향상시키며 데이터베이스의 저장 공간을 효율적으로 사용할 수 있도록 한다. 결과적으로 기존의 시스템에 대하여 유비쿼터스 센서 네트워크의 안정성을 확보할 수 있었고 실시간 전송 모듈의 프로세스 점유율을 약 20% 감소시킬 수 있었으며 실제 측정한 ECG를 압축한 결과 25.6:1의 압축률에서 약 3.25%의 PRD를 가지는 효율적인 ECG 관리가 이루어질 수 있었다.

• 센서학회지
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• 제21권5호
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• pp.352-358
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• 2012

A sensor network system can be an efficient tool for healthcare telemetry for multiple users due to its power efficiency. One drawback is its limited data size. This paper proposed a real-time application of data compression/decompression method in u-Health monitoring system in order to improve the network efficiency. Our high priority was given to maintain a high quality of signal reconstruction since it is important to receive undistorted waveform. Our method consisted of down sampling coding and differential Huffman coding. Down sampling was applied based on the Nyquist-Shannon sampling theorem and signal amplitude was taken into account to increase compression rate in the differential Huffman coding. Our method was successfully tested in a ZigBee and WLAN dual network. Electrocardiogram (ECG) had an average compression ratio of 3.99 : 1 with 0.24% percentage root mean square difference (PRD). Photoplethysmogram (PPG) showed an average CR of 37.99 : 1 with 0.16% PRD. Our method produced an outstanding PRD compared to other previous reports.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.450-453
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• 2002

In emergency telemedicine system based on wireless communication system with limited transmission capacity, it is necessary to transmit the biological data (ECG, BP, Respiration, $SpO_2$) of the patient continuously and reliably in real time. For this service, it is necessary to data compression and error control. In this study, we designed an protocol for error control in application layer and implemented it on the biological data transmission program for an emergency telemedicine system based on wireless data communication system.

• 대한의용생체공학회:의공학회지
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• 제19권3호
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• pp.251-260
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• 1998

홀터 심전계는 심장 이상으로 인한 급사 위험이 있는 환자를 위한 비관혈인 진단 장비이다. 본 연구에서는 일상생활 중에 심전도 데이터를 획득할 수 있도록 원칩 마이크로프로세서와 대용량메모리인 플레쉬 메모리(flash memory) 카드를 이용하여 2채널의 홀터 심전계를 설계하였다. 시스템 하드웨어는 크게 원칩 마이크로프로세서(68HC11E9)의 아날로그 심전도 처리회로, 플레쉬 메모리 카드로 구성하였다. 아날로그 심전도 처리회로는 250,500,1000의 이득을 갖는 증폭기와 0.05-100Hz의 대역폭을 갖는 대역통과 필터, 호흡으로 인한 기저선의 이동을 제거하기 위한 auto-balancing 회로와 포화-보정회로를 사용하였다. 심전도 신호는 240샘플/초 샘플링하여 A/D 변환하였다. 심전도는 필터링 및 전처리 과정을 통하여 특징점인 Q-R-T파를 검출하고, 이를 근거로 템플리트 생성, ST레벨, 심박수, QT간격 측정과 부정맥을 검출하였다. 또한 장시간동안의 심전도 데이터와 측정된 진단파라미터를 저장하기 위해 실시간 압축 알고리즘인 MFan과 delta modulation 방법을 이용하여 데이터를 압축, 저장하였다. 20M 바이트 용량의 플레쉬 메모리 카드에 기록된 데이터는 PC의 DOS나 Windows 환경의 ambulatory monitoring 분석시스템과 쉽게 인터페이스가 가능하도록 FFS(Flash File System)의 호환 가능한 SBF(Symetric Block format)포맷으로 저장하여 분석시스템에서 데이터 처리 및 관리할 수 있게 하였다.