모듈형 환자 모니터의 개발

우응제,박승훈 대한의용생체공학회 1997 의공학회지 Vol.18 No.2

In this paper, we describe the design methodology and specifications of the developed module-based bedside monitors for patient monitoring. The bedside monitor consists of a main unit and module cases with various parameter modules. The main unit includes a 12.1" TFT color LCD, a main CPU board, and peripherals such as a module controller, Ethernet LAN card, video card, rotate/push button controller, etc. The main unit can connect at maximum three module cases, each of which can accommodate up to 7 parameter modules. They include the modules for electrocardiograph, respiration, invasive blood pressure, noninvasive blood pressure, temperature, and SpO with plethysmograph.raph.

유한 요소법에 의한 인체내 전계분포 해석용 소프트웨어 개발 ( Finite Element Software Package for Analysis of Electric Field Distribution in Human Body )

우응제 대한전자공학회 1993 대한전자공학회 학술대회 Vol.1993 No.5

생체신호 측정 및 종합관리 시스템 ( SiMACS ) ( Biological Signal measurement , Archiving , and Communication System ( SiMACS ) )

우응제,박승훈 대한전자공학회 1994 대한전자공학회 학술대회 Vol.1994 No.5

환자모니터링시스템의 개발 : 전체구조 및 기본사양

우응제,박승훈 대한의용생체공학회 1997 의공학회지 Vol.18 No.1

We have developed a patient monitoring system including module-based bedside monitors, interbed network, central stations, clinical workstations, and DB servers. A bedside monitor with a color LCD can accommodate up to 3 module cases and 21 different modules. Six different physiological parameters of ECG, respiration, invasive blood pressure, noninvasive blood pressure, body temperature, and arterial pulse oximetry with plethysmoyaph are provided as parameter modules. In a single bedside monitor, modules and a module controller communicate with IMbps data rate through an intrabed network based on RS-485 and HDU protocol. At the same time, it communicates with other bedside monitors and central stations through interbed network based on 1 OMbps Ethernet and TCP/IP protocol. Central stations using 20" color CRT monitors can be connected with many bedside monitors and they display 18 channels of waveforms simultaneously. Clinical workstations are used mainly for the review of patient datE In order to accommodate more advanced data management capabilities such as 24-hour full disclosure, we have developed a relational database server dedicated to the patient monitoring system. Software for bedside monitor, central station, and clinical workstation fully utilizes graphical user interface techniques and all functions are controlled by a rotate/push button on the bedside monitor arid a mouse on the central station and clinical workstation. The entire system satisfies the requirements of AAMI and ANSI standards in terms of electrical safety and performances.nces.

Computer Simulation에 생체내 포도당 동태에 관련된 생리변수의 분리에 관한 연구 ( Separation of Physiological Faction Influencing Glucose-Insulin Kinetics Using Computer Simulation Method )

우응제,민병구,이충웅 대한전자공학회 1983 대한전자공학회 학술대회 Vol.1983 No.1

다채널 심전도에서의 두가지 Source Consistency Filtering 알고리즘의 해석

우응제,강곤,Woo, E. J.,Khang, G. 대한의용생체공학회 1999 의공학회지 Vol.20 No.3

다채널의 심전도 신호에서, 소수의 리이드에 만 잡음이 유기되고 나머지 대부분의 리이드 신호들은 이 잡음과 통계적인 상관 관계가 없을 때, source consistency filtering(SCF) 은 이러한 잡음의 감쇄에 매우 효과적이다. 특히, SCF는 원래 신호의 왜곡을 최소화하면서 , 선택적으로 잡음 만을 제거하는 매우 우수한 특성을 가진다. 이러한 특성은 하나의 신호원에서 기인하는 다채널 신호들의 공간적 및 시간적 상관관계를 모두 이용함으로서 가능하다. 본 논문에서는 SCF의 원리 및 구현 방법을 구체적으로 기술하여 이 방법에 대한 이해를 증진하고자 한다. 또한 기존의 방법을 개선한 새로운 SCF를 제안하였으며 , 이의 효과적인 구현에 필요한 알고리즘의 상세한 설계 지침을 제시하였다. 다채널의 심전도 신호를 대상으로 하여 그 성능을 검증하였고, 현재의 SCF 가 가지는 한계를 명확히 하며, 개선의 방향을 제시하였다. Source consislency filtering (SCF) is very effective at removing nOIse when only one or a few leads among multi-lead ECG signals are contaminated. When the noise at one or only a few leads are statistically uncorrelated with signals at other leads, SCF seleclIvely removes the noise with a neglIgIble amount of distortion in the original signal waveform. In order to enhance the understanding of this new method, we describe the lheory and implementational details of SCF in this paper. Numerical implementation and test results of SCF on a multi-lead ECG dalabase show that SCF is a new kind of adaptive filters utilizmg spatial as well as temporal information in multi-c.hannel signals origmatmg from a single source. We also describe the limitations and future improvements in using SCF.

환자 모니터링 시스템에서의 통신 방식(I) : 인트라베드 통신망

우응제,박승훈,김경수,최근호,김승태,이희철,서재준,김형진 대한의용생체공학회 1997 의공학회지 Vol.18 No.4

본 논문은 개발된 환자 모니터링 시스템에서 사용하고 있는 인트라베드 통신망에 대하여 기술한다. 인트라베드 통신망은 모듈형 환자 모니터의 본체와 이에 연결되는 여러 종류의 생체 신호 측정 모듈들 사이의 데이터 통신망을 의미한다. 모듈형 환자 모니터에서의 데이터 통신에 대한 필요 사항들에 대한 분석을 기초로 하여, 인트라베드 통신망은 1Mbps의 통신 속도를 가지도록 하였고, RS-485와 HDLC통신 규격을 채용하였다. 데이터의 교환은 패킷, 프레임 및 스트림의 세가지 데이터 구조에 의해 구현하였다. 개발된 환자 모니터에서의 인트라베드 통신망의 설계 및 구현과 구 사양 및 성능을 기술한다. In this paper, we describe the intrabed network in a patient monitoring system we developed The intrabed network handles data communication between the main unit of a bedside patient monitor and parameter modules plugged in it. We designed the intrabed network based on RS-485 and HDLC protocol with 1 Mbps data rate. Message exchanges are implemented based on three data structures of packet frame. and stream. We present the specification and the performance of the data communication network for the developed patient monitor.

Three-dimensional MREIT Simulator of Static Bioelectromagnetism and MRI

우응제,Atul S. Minhas,Zijun Meng,Young Tae Kim,김형중,김혜현 대한의용생체공학회 2011 Biomedical Engineering Letters (BMEL) Vol.1 No.2

Purpose Magnetic resonance electrical impedance tomography (MREIT) aims to produce high-resolution cross-sectional images of a conductivity distribution inside the human body. We perform conductivity image reconstructions based on a relation between the conductivity distribution and induced magnetic flux density distributions subject to externally injected currents. This induced magnetic flux density is measured in MREIT using an MRI scanner. To facilitate MREIT research, we need a numerical simulator including static bioelectromagnetism and MRI data collection process. In this paper, we describe the development of a threedimensional MREIT simulator (MREITSim). Methods We describe various features of MREITSim including geometry modeling, meshing, finite element modeling and numerical computations of magnetic flux density and k-space MR data. We demonstrate the underlying bioelectromagnetic phenomena and MR data collection process using phantom models of without and with anomaly. We illustrate effects of noise in MR data and echo time on magnetic flux density computations. Results We demonstrate numerical computations of current density and magnetic flux density distributions for current injections orthogonal to z-direction, the direction of the main magnetic field of an MRI scanner. The k-space MREIT data generation procedure is illustrated using a phantom model with an insulating anomaly. Conclusions The simulator functions as a virtual MREIT scanner and provides quantitative numerical results of intended experimental studies. We suggest the simulator as a basic research tool for future MREIT studies of its theory, algorithm,experimental techniques and pulse sequence design.

Late Potential의 검출을 위한 고해상도 심전계의 개발

우응제,박승훈 대한의용생체공학회 1996 의공학회지 Vol.17 No.4

Most of the conventional electrocardiowaphs foil to detect signals other than P-QRS-T due to the limited SNR and bandwidth. High-resolution electrocardiography(HRECG) provides better SNR and wider bandwidth for the detection of micro-potentials with higher frequency components such as vontricular late potentials(LP). We have developed a HRECG using uncorrected XYZ lead for the detection of LPs. The overall gain of the amplifier is 4000 and the bandwidth is 0.5-300Hz without using 60Hz notch filter. Three 16-bit A/D converters sample X, Y, and Z signals simultaneously with a sampling frequency of 2000Hz. Sampled data are transmitted to a PC via a DMA-controlled, optically-coupled serial communication channel. In order to further reduce the noise, we implemented a signal averaging algorithm that averaged many instances of aligned beats. The beat alignment was carried out through the use of a template matching technique that finds a location maximizing cross-correlation with a given beat tem- plate. Beat alignment error was reduced to $\pm$0.25ms. FIR high-pass filter with cut-off frequency of 40Hz was applied to remove the low frequency components of the averaged X, Y, and Z signals. QRS onset and end point were determined from the vector magnitude of the sigrlaIL and some parameters needed to detect the existence of LP were estimated. The entire system was designed for the easy application of the future research topics including the optimal lead system, filter design, new parameter extraction, etc. In the developed HRECG, without signal averaging, the noise level was less than 5$\mu$V$_rms RTI$. With signal averaging of at least 100 beats, the noise level was reduced to 0.5$\mu$V$_rms RTI$, which is low enough to detect LPs. The developed HRECG will provide a new advanced functionality to interpretive ECG analyzers.

임피던스 단층 촬영기의 정적 영상 복원 알고리즘 ( A Static Image Reconstruction Algorithm in Electrical Impedance Tomography )

우응제,John G. Webster,Willis J. Tompkins 대한전자공학회 1991 대한전자공학회 학술대회 Vol.1991 No.5