This paper introduces a problem-based learning (PBL) microprocessor application course designed a... more This paper introduces a problem-based learning (PBL) microprocessor application course designed according to the following strategies: 1) hands-on training without having a formal laboratory, and 2) intense student-centered cooperative learning through an ill-structured problem. PBL was adopted as the core educational technique of the course to accomplish student learning outcomes such as fundamental knowledge acquisition and applications, practical design experiences, problem-solving skills, higher-order thinking, teamwork and communication skills, and lifelong self-directed learning capability. In the designed course, students were required to build their own hardware system on a breadboard and learn how to program, download, and execute from a student mentor's demonstration. Students were also asked to choose a design topic for their team project with minimum guidelines and were encouraged to learn whatever was necessary to accomplish the project autonomously. The course has been offered for two years and has obtained overwhelming positive feedback from students.
The characterization of microemboli located in whole blood is attempted by determining the Legend... more The characterization of microemboli located in whole blood is attempted by determining the Legendre coefficients of phase function from the scattered light distribution around the medium. In the radiative transport equation, a microembolus is represented as a secondary source and assumed to have a spherical form and the first order transport approximate solution of the equation is used to describe the scattered intensity distribution. After the scattered intensities are determined at the surfaces of the medium, the orthogonal property of Legendre polynomial is used to extract the coefficients out of the intensities. From the obtained coefficients, the size and complex index of refraction of microemboli are determined
An analytical solution method of radiative transport equation that describes light scattering dis... more An analytical solution method of radiative transport equation that describes light scattering distribution in whole blood is derived by applying successive order scattering approximation and transport approximation. By separating the coherent component of scattered fluxes, the transport equation can be represented in terms of each order scattering fluxes, and the scattering contribution term of each order scattering equations becomes simplified for an easy solution that is usually complicated and even impossible. The method is then used to calculate the light reflectance from a half-space blood medium and compared with experimental data
The production of blood microemboli (BME) was studied using an ex vivo exteriorized left ventricu... more The production of blood microemboli (BME) was studied using an ex vivo exteriorized left ventricular assist device (LVAD) model in calves. Each of eight calves received a series of three LVADs, each operating for 24 hr. Blood microemboli were measured directly by a laser (624 nm and 828 nm) light scattering microemboli detection (LSMD) system through the LVAD outflow cannula and by constant pressure filtration (CPF) of blood samples from the LVAD outflow cannula. Hematologic parameters were also measured. After LVAD removal, perivalvular thrombi were evaluated using polar coordinate mapping. The average LSMD and CPF results correlated. For example, in one series of three calves, one ventricle exhibited significantly greater thrombogenesis than did the other ventricles, as indicated by both the LSMD and CPF results. In a series of five calves, one calf developed an abnormally high activated thromboplastin time (APTT), even in the absence of heparin. For two of the three ventricles tested in that calf, microemboli concentration (CPF), Factor XII activity, level of fibrin degradation products (FDP), and accumulated thrombus were significantly lower than for the other calves. The whole blood viscosity (WBV, at 230 s-1) in this calf also decreased to lower values than were seen with the other calves.
This paper introduces a real-time data compression and transmission algorithm between e-health te... more This paper introduces a real-time data compression and transmission algorithm between e-health terminals for a periodic ECGsignal. The proposed algorithm consists of five compression procedures and four reconstruction procedures. In order to evaluate the performance of the proposed algorithm, the algorithm was applied to all 48 recordings of MIT-BIH arrhythmia database, and the compress ratio (CR), percent root mean square difference (PRD), percent root mean square difference normalized (PRDN), rms, SNR, and quality score (QS) values were obtained. The result showed that the CR was 27.9:1 and the PRD was 2.93 on average for all 48 data instances with a 15% window size. In addition, the performance of the algorithm was compared to those of similar algorithms introduced recently by others. It was found that the proposed algorithm showed clearly superior performance in all 48 data instances at a compression ratio lower than 15:1, whereas it showed similar or slightly inferior PRD performance for a data compression ratio higher than 20:1. In light of the fact that the similarity with the original data becomes meaningless when the PRD is higher than 2, the proposed algorithm shows significantly better performance compared to the performance levels of other algorithms. Moreover, because the algorithm can compress and transmit data in real time, it can be served as an optimal biosignal data transmission method for limited bandwidth communication between e-health devices.
An automatic gain control (AGC) algorithm is implemented in a pacemaker to improve sensing perfor... more An automatic gain control (AGC) algorithm is implemented in a pacemaker to improve sensing performance and minimize human intervention. The sense amplifier gain is controlled automatically by electrogram amplitude. The sensing threshold (sensitivity) is set between 20 and 30% of the intrinsic peak amplitude. Sensing performance of the AGC algorithm is evaluated using 12 human intracardiac electrograms. The performance is
This paper introduces a problem-based learning (PBL) microprocessor application course designed a... more This paper introduces a problem-based learning (PBL) microprocessor application course designed according to the following strategies: 1) hands-on training without having a formal laboratory, and 2) intense student-centered cooperative learning through an ill-structured problem. PBL was adopted as the core educational technique of the course to accomplish student learning outcomes such as fundamental knowledge acquisition and applications, practical design experiences, problem-solving skills, higher-order thinking, teamwork and communication skills, and lifelong self-directed learning capability. In the designed course, students were required to build their own hardware system on a breadboard and learn how to program, download, and execute from a student mentor's demonstration. Students were also asked to choose a design topic for their team project with minimum guidelines and were encouraged to learn whatever was necessary to accomplish the project autonomously. The course has been offered for two years and has obtained overwhelming positive feedback from students.
The characterization of microemboli located in whole blood is attempted by determining the Legend... more The characterization of microemboli located in whole blood is attempted by determining the Legendre coefficients of phase function from the scattered light distribution around the medium. In the radiative transport equation, a microembolus is represented as a secondary source and assumed to have a spherical form and the first order transport approximate solution of the equation is used to describe the scattered intensity distribution. After the scattered intensities are determined at the surfaces of the medium, the orthogonal property of Legendre polynomial is used to extract the coefficients out of the intensities. From the obtained coefficients, the size and complex index of refraction of microemboli are determined
An analytical solution method of radiative transport equation that describes light scattering dis... more An analytical solution method of radiative transport equation that describes light scattering distribution in whole blood is derived by applying successive order scattering approximation and transport approximation. By separating the coherent component of scattered fluxes, the transport equation can be represented in terms of each order scattering fluxes, and the scattering contribution term of each order scattering equations becomes simplified for an easy solution that is usually complicated and even impossible. The method is then used to calculate the light reflectance from a half-space blood medium and compared with experimental data
The production of blood microemboli (BME) was studied using an ex vivo exteriorized left ventricu... more The production of blood microemboli (BME) was studied using an ex vivo exteriorized left ventricular assist device (LVAD) model in calves. Each of eight calves received a series of three LVADs, each operating for 24 hr. Blood microemboli were measured directly by a laser (624 nm and 828 nm) light scattering microemboli detection (LSMD) system through the LVAD outflow cannula and by constant pressure filtration (CPF) of blood samples from the LVAD outflow cannula. Hematologic parameters were also measured. After LVAD removal, perivalvular thrombi were evaluated using polar coordinate mapping. The average LSMD and CPF results correlated. For example, in one series of three calves, one ventricle exhibited significantly greater thrombogenesis than did the other ventricles, as indicated by both the LSMD and CPF results. In a series of five calves, one calf developed an abnormally high activated thromboplastin time (APTT), even in the absence of heparin. For two of the three ventricles tested in that calf, microemboli concentration (CPF), Factor XII activity, level of fibrin degradation products (FDP), and accumulated thrombus were significantly lower than for the other calves. The whole blood viscosity (WBV, at 230 s-1) in this calf also decreased to lower values than were seen with the other calves.
This paper introduces a real-time data compression and transmission algorithm between e-health te... more This paper introduces a real-time data compression and transmission algorithm between e-health terminals for a periodic ECGsignal. The proposed algorithm consists of five compression procedures and four reconstruction procedures. In order to evaluate the performance of the proposed algorithm, the algorithm was applied to all 48 recordings of MIT-BIH arrhythmia database, and the compress ratio (CR), percent root mean square difference (PRD), percent root mean square difference normalized (PRDN), rms, SNR, and quality score (QS) values were obtained. The result showed that the CR was 27.9:1 and the PRD was 2.93 on average for all 48 data instances with a 15% window size. In addition, the performance of the algorithm was compared to those of similar algorithms introduced recently by others. It was found that the proposed algorithm showed clearly superior performance in all 48 data instances at a compression ratio lower than 15:1, whereas it showed similar or slightly inferior PRD performance for a data compression ratio higher than 20:1. In light of the fact that the similarity with the original data becomes meaningless when the PRD is higher than 2, the proposed algorithm shows significantly better performance compared to the performance levels of other algorithms. Moreover, because the algorithm can compress and transmit data in real time, it can be served as an optimal biosignal data transmission method for limited bandwidth communication between e-health devices.
An automatic gain control (AGC) algorithm is implemented in a pacemaker to improve sensing perfor... more An automatic gain control (AGC) algorithm is implemented in a pacemaker to improve sensing performance and minimize human intervention. The sense amplifier gain is controlled automatically by electrogram amplitude. The sensing threshold (sensitivity) is set between 20 and 30% of the intrinsic peak amplitude. Sensing performance of the AGC algorithm is evaluated using 12 human intracardiac electrograms. The performance is
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Papers by Jungkuk Kim