Plasma protein adsorption is the first event in the blood-material interaction and influenc- es subsequent platelet adhesion towards thlㅈombus formation. Thiㅈomboembolic events are strongly influenced by surface characteristics of materials and fluid dynamics inside the blood pump. In vitro flow visualizaion and an amimal experiment with the moving actuator type TAH were Performed in order to investigate fluid dynamic effects on the protein adsorption. The diffel'encl level, j of shear rate inside the ventricle Lvere determined by consid- ering the direction of the major opening of four healt valves in the implanted TAH and the visualized flow patterns as well. Each ventricle of the explanted TAH was sectionalized into 12 segments according to the shear rate level. The adsorbed protein on each segment was quantified using the ELISA method after soaking in 2% (wye)SDS/PBS for two days. Adsorbed protein layer thicknesses Itvere measured by the Immunogotd method under TEM. The SEM observation show that right ventricle (RV) , immobilized with albumin, displayed different degrees of platelet adhesion on each segment, whereas the left ventricle (LV), grafted by PEO-sulronate, indicated nearly , iame platelet adhesion behavior, regardless of shear rates. The surface concentrations of adsorbed proteins in the low shear rate region are hlghel'than those in the high region, which was confirmed statistically. A modified adsorption model of plasma protein onto polyurethane surface was suggested by considering the effect of the fluid dynamic characteristics.

This paper deals with a subject for implementation of L+ayer 1 and Layer 2(LAPD) of ISDN user-network interface on the basis of CCITT recommandation I.411, I.412, I.441 (Q.921), I.450(Q.930) and I.451 (Q.931) for ultrasonic image transfer. For the implementa tion of LAPD protocol of ISDN in this study. PC-CARD based hardware(TA :Terminal Adopt) is proposed and operating system (PC-XINU) supporting the Multiprocessing is transplanted to it. As the Service Access Point(SAP) is accessed by using the port of XINU and Layers which consist of transmitting and receiving part are independantly processed for each other in this proposed system. It can be easy and flexible to implement LAPD protocol for the message transfer.

Recently, microcomputer technology has been developed rapidly and it provides not only graphic user interface that can be fraendly accessable but also large storage capacity to han- dle much hospital information. Almost all the order communication system for hospital has been developed under the concept of host and terminal environment since last 20 years. However, host-terminal system has not been successful in korea simply because most of physicians prescibe for rrlany patients a day(sometimes more than 150 patients a day). Also, under the host-terminal environment, programs are not friendly implemented for users. Since March 1991, we had developed order communication system for out-patients(named YONSEI-PC) using personal computer(PC) and local area network(LAN) . Since September 1992, we has applied succesfully in the Yonsei Cardiovascular Center, Sevrance Hospital, Yonsei University College of Medicine. This system consisted with Server and Clients which is communicated through LAN(Ethernet). The system also use the Host computer(IBM 9221 170) as a data bank and communicates to the Server with emulation card(3270 emulator, Interlink Inc., Korea) . After introducing this system, it enables patients to receive drugs witllin 20 minutes after prescription of 300-400 patients per day and it seemed to be effective system not to reduce waiting time for the patients but also to remove charge-troubling(due to His-entry of prescription) . This system also seems to be effective in terms of office automatism for hospital management. However users, usually physitions, required more friendly and easy system to operate and we thought that the most important one to successfully introduce order communication computer system in the hospital is user interface.

Automatic transmission of data from the blood analyzer to the request site is one of the most important part in hospital computerization. We have developed a system that transmits data from the arterial blood gas analyzer to the request site automatically In this system HOST computer, FILE server,'LAN(Local Area Network) , 3270 Emulator and bfulti-port card are integrated with 3 blood gas analyzers(NOVA Inc., USA) which are connected to a single multi-port card in a personal computer. When specimen are collected from tramp)inly sites, they are transferee to the laboratory In the Yonsei Cardiovascular Center After analysis, the result is transmitted to the personal computer via serial commnunication between machine and multi-port card using interrupt method. Then, the patient's information (Name, Patient ID No., etc.) is obtained from the HOST computer througth the emulator. The combined data (patient information & lab data) is transmitted to each request site via LAN automatically These results are stored in the File Server for one year and they can be reviewed anytime. Also, it could be used for the various statistics and the flow chart for clinical research. Additionally, we found thal this system reduces the personal labor.

The high biocompatibility of titanium is connected with the high corrosion resistance of the surface oxide, its high dielectric constant, and some other specific biochemical properties of the oxide. The corrosion resistance of titanium can be improved with the formation of passive film by anodic oxidation. In other to characterize the titantium oxlde film formed by anodic oxidation, titanium plates were anodized in 0.5M $H_3SO_4$ electrolyte at voltages between 5V and 100v. The oxide film was examined by an X-Ray Diffractometer(XRD) and a Scanning Electron Microscope(SEM). In addition, the corrosion resistance of oxide film was tested by dipping in physiological NaCl,5% HCI,5% $H_3PO_4$ and its biocompatability was evaluated by the fibroblast-like cell culture. The results obtained are as follows : 1. The thickness of surface oxide and micropore are increased with the increase of electrode potential and formed deeply along the grain boundary. 2. The solubilities of titanium in electrolyte solution shows that the anodized titanium has more corrosion resistance than the untreated pure titanium. 3. The biocomatibility of anodized titanium is superior to untreated pure titanium.

Automated system to analyze liver function test results is presented based on fuzzy logic knowledge. Clinician's knowledge and experience was first expressed in linguistic terms fol- lowed by conversion to numerical values to create membership functions of disease possibility for each test item and liver disease. Membership functions were then compensated for different relative importances of test items. Liver diseases considered were acute viral hepatitis (AVH), chronic persistent hepatitis(CPH), chronic active hepatitis(CAH), and liver cirrhosis(LC), Liver function test results of alanine aminotransferase(ALT), aspartate amino- transferase(AST) , glutamate dehydrogenase(GDH), ornithine carbamyltransferase(OCT) , ALT/AST, and 10* GDH/ALT in 218 patients were analyzed by the present system, welch resulted in 80% accuracy. AVH and CAH showed the highest 93 % and the lowest 58% ac- curacies, respectively, which was similar to the clinician's expectation. The simple mathemat- ical formulation of the present system would enable an easy implementation in commercial analysis instruments. Also, the identical fuzzy logic can be applied to similar diagnostic envi- ronments in general.

To investigate the relations between the physical constitutions, the acid-base balance, and the autonomic nervous function, the blood gas, the heart rate and the concentrations of Na, K of serum were measured pre-and poststimulation. As the result, it is shown that in the normal condition the macro-negative(strong liver- weak lung type) is the metabolic alkalosis, the macro-positive (strong lung-weak liver type) is the metabolic acidosis, the micro-negative(strong kidney-weak spleen type) is the alkalosis and the micro-positive (strong spleen-weak kidney type) is the acidosis. And the ntacro-positive and micro-positive are the sympathetic lead, the macro-negative and micro-negative are the parasympathetic lead. In the macro-positive and micro-positive subjects, the concentration of K in serum is relatively high. This si coincided with the acidosis. But in the macro-negative and micro-negative subjects, the concentration of K in serum is relatively low. This is coincided with the alkalosis.

Clinical laboratory order communication system was developed to run fast and effective laboratory tests at the Chungbuk National University Hospital. The present system incorporated with the main Hospital Management Information System accepts :aboratory orders, classifies them based on the predefined logical system, and outputs various practical informations for the user. These assist sample taking, sample management, and work plan organization. A special care was taken to the sample management by introducing the bar code system. The system was written in the INFOS hierarchical database and COBOL, and is currently in the practical use for both in - and out-ward patients. The present system enabled fast and effective data communication as well as reducing the time and man power indispensable when the manual slips are used for order communication.

Of the assumptions commonly used in continuous infection model, the least likely to be even approximately true in large population, is that of homogeneous mixing. In this paper, We investigate a model for the spread of infection amongst a population which is divided into classes, such that the individuals of each class mix homogeneously amongst themselves, but mix to a lesser degree with individuals of other class. The stochastic model in this form is intractable and approximations are made, yielding results in reasonable agreement with simulation trials.

A new recognition algorithm which decides thge opening & the closing states of subject's eye and isn't affected by the subject's background is proposed. And it is tested in circumstances in which subject's motions are not restricted using the developed system. AERS (Automatic Eye opening & closing Recognition System) . The significant characteristic of the AERS is that it dosen't need any extra hardware except a formal CCD carmera and an image grabber but it works so well and so fast. The AFRS wcould be particularly well suited to a tray of communications of patients in a hospital, who can not communicate othertvise.

This paper describes design of a Chaos analyser and its applications to analysis of nonlinear characteristirs of ECG. The proposed system can easily distinguish chaotic system among the various dynamical systems by chaotic quantitative and qualitative analysis and also chaotic characteristics which represents states of nonlinear dynamical system. And we have also proposed new possibilities to recognize abnormal state of ECG signal using the chaotic characteristics.

In this paper, a laryngeal function identification system based-on the EGG signal is proposed as the decision basis whether the laryngeal function is normal or abnormal. The normal EGG signal is approved an autoregressive model which has the optimal order of 9. It can be analized by determining the transfer function. But it is not meaningful that the determi- nation is made using the transfer function of an autoregressive model on the abnormal EGG signal. The power spectral analysis was applied to discriminate the normal or abnormal cases. The SNR of the EGG signal was enhanced by the optimal position of electrodes.