• 대한의용생체공학회:의공학회지
• /
• 제6권2호
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• pp.1-8
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• 1985

The wall shear stress in the vicinity of end-to end anastomoses under steady flow conditions was measured using a flush-mounted hot-film anemometer(FMHFA) probe. The experimental measurements were in good agreement with numerical results except in flow with low Reynolds numbers. The wall shear stress increased proximal to the anastomosis in flow from the Penrose tubing (simulating an artery) to the PTFE: graft. In flow from the PTFE graft to the Penrose tubing, low wall shear stress was observed distal to the anastomosis. Abnormal distributions of wall shear stress in the vicinity of the anastomosis, resulting from the compliance mismatch between the graft and the host artery, might be an important factor of ANFH formation and the graft failure. The present study suggests a correlation between regions of the low wall shear stress and the development of anastomotic neointimal fibrous hyperplasia(ANPH) in end-to-end anastomoses. 30523 T00401030523 ^x Air pressure decay(APD) rate and ultrafiltration rate(UFR) tests were performed on new and saline rinsed dialyzers as well as those roused in patients several times. C-DAK 4000 (Cordis Dow) and CF IS-11 (Baxter Travenol) reused dialyzers obtained from the dialysis clinic were used in the present study. The new dialyzers exhibited a relatively flat APD, whereas saline rinsed and reused dialyzers showed considerable amount of decay. C-DAH dialyzers had a larger APD(11.70$\pm$1.32mmHg/min)compared to CF dialyzers(4.32$\pm$0.55mmHg/min)(p<0.05). However, there was no observable difference in the UFR between the two dialyzers. Neither APD nor UFR showed any significant increase with an increasing number of reuses for up to more than 20reuses. A substantial number of failures observed in APD(larger than 20mmHe/min)on the reused dialyzers(2 out of 40 CP and S out 26 C-DAK) were attributed to the Possible damage on the fibers. The CF 15-11 HFDs which failed APD test did not show changes in the UFR compared to normal dialyzers indicating that APD is a more sensitive test than UFR test to evaluate the integrity of the fibers. 30527 T00401030527 ^x For quantitative measurement of reflected light from a clinical diagnostic strip, a prototype old reflectance photometer was designed. The strip loader and cassette were made to obtain more accurate reflectance parameters. The strip was illuminated at 45˚c through optical fiber and the intensity of reflected light was determined at rectanguLat angle using a photodiode. The kubelka-munk coefficient and reflection optical density were determined ar four different wavelengths(500, 550, 570 and 610nm) for blood glucose strip. For higher concentration than 300mg/41 about glucose, a saturation state of abforbance was observed at 500, 550 and 570nm. The correlation between glucose concentration and parameters was the best at 610nm. 30535 T00401030535 ^x Radiation-induced fibrosarcoma tumors were grown on the flanks of C3H mice. The mice were divided into two groups. One group was injected with Photofrin II, intravenously (2.5mg/kg body weight). The other group received no Photofrin II. Mice from both groups were irradialed for approximately 15 minutes at 100, 300, or 500 mW/cm2 with the argon (488nm/514.5 nm), dye(628nm) and gold vapor (pulsed 628 nm) laser light. A photosensitizer behaved as an added absorber. Under our experimental conditions, the presence of Photolfrin II increased surface temperature by at least 40% and the temperature rise due to 300 mW/cm2 irradiation exceeded values for hyperthermia. Light and temperature distributions with depth were estimated by a computer model. The model demonstrated the influence of wavelength on the thermal process and proved to be a valuable tool to investigate internal temperature rise. 30536 T00401030536 ^x We investigated the structural geometry of thirty-eight Korean femurs. The purpose of this study is to identify major geometrical differences between Korean femurs 3nd others that we believe belong to Caucasians so that we would be able to get insights into the femoral component design that fits Asians including Koreans. We utilized computerized tomography (CT) images of femurs extracted from cadavers. The CT images were transformed into bitmap data by using a film scanner, and then analyzed by using a commercially available software called Image v.1.0 and a Macintosh IIci computer.The resulting data were compared with already published data. The major results show that the geometry of the Korean femurs is significantly different from that of Caucasians: (1) the anteversion angle and the canal flare index are greater by the amount of approximately 8˚ and 0.5, respectively, (2) the shape of the isthmus cross section is more round, and (3) the distance between the teaser trochanter and the proximal border of the isthmus is shelter by about 15 mm. The results suggested that the femoral component suitable for Asians should be different from the currently-used components designed and manufactured mostly by European or American companies. 30537 T00401030537 ^x It is well known that nonlinear propagation characteristics of the wave in the tissue may give very useful information for the medical diagnoisis. In this paper, a new method to detect nonlinear propagation characteristics of the internal vibration in the tissue for the low frequency mechanical vibration by using bispectral analysis is proposed. In the method, low frequency vibration of f0( = 100Hz) is applied on the surface of the object, and the waveform of the internal vibration x (t) is measured from Doppler frequency modulation of silmultaneously transmitted probing ultrasonic waves. Then, the bispectra of the signal x (t) at the frequencies (f0, f0) and (f0, 2f0) are calculated to estimate the nonlinear propagation characteristics as their magnitude ratio, w here since bispectrum is free from the gaussian additive noise we can get the value with high S/N. Basic experimental system is constructed by using 3.0 MHz probing ultrasonic waves and the several experiments are carried out for some phantoms. Results show the superiority of the proposed method to the conventional method using power spectrum and also its usefulness for the tissue characterization. 30541 T00401030541 ^x This paper describes the implementation of a computerized radial pulse diagnosis by aids of a clinical expert. On this base, we composed of the radial pulse diagnosis system in korean traditional medicine. The system composed of a radial pulse wave detection system and a radial pulse diagnosis system. With a detection system, we detected Inyoung and Cheongu radial pulse wave and processed it. Then, we have got the characteristic parameters of radial pulse wave and also quantified that according to the method of Inyoung-Cheongu Comparison Radial Pulse Diagnosis. We defined the jugement standard of radial pulse diagnosis system and then we confirmed the possibility for realization of automatic radial pulse diagnosis in korean traditional medicine. 30545 T00401030545 ^x Microspheres are expected to be applied to biomedical areas such as solid-phase immunoassays, drug delivery systems, immunomagnetic cell separation. To synthesize microspheres for biomedical application, "two stage shot growth method" was developed. The uniformity ratio of synthesized microspheres was always smaller than 1.05. And the surface charge density (or the number of ionizable functional groups) of the microspheres synthesized by "two stage shot growth method" was 6~13 times higher than that of the microspheres synthesized by conventional seeded batch copolymerization. As a previous step for biomedical application, adsorption experiments of bovine albumin on microspheres were carried out under various conditions. The maximum adsorbed amount was obtained in the neighborhood of pH 4.5. Isoelectric point of bovine albumin is pH 5.0, so experimental result shows that it shifted to acid area. The adsorption isotherm was obtained, the plateau region was always reached at 2.Og/L (bulk concentration of bovine albumin).The effect of the kind and the amount of surface functional group was also examined. 30575 T00401030575 ^x A medical image workstation was developed using multimedia technique. The system based on PC-486DX was designed to acquire medical images produced by medical imaging instruments and related audio information, that is, doctors' reporting results. Input information was processed and analyzed, then the results were presented in the form of graph and animation. All the informations of the system were hierarchically related with the image as the apex. Processing and analysis algorithms were implemented so that the diagnostic accuracy could be improved. The diagnosed information can be transferred for patient diagnosis through LAN(local area network). 30592 T00401030592 ^x In the conventional infrared imaging system, complex infrared lens systems are usually used for directing collimated narrow infrared beams into the high speed 2-dimensional optic scanner. In this paper, a simple reflective infrared optic system with a 2-dimensional optic scanner is proposed for the realization of medical infrared thermography system. It has been experimentally proven that the intfrared thermography system composed of the proposed optic system has the temperature resolution of 0.1˚c under the spatial resolution of lmrad, the image matrix size of 256 X 240, and tile imaging time of 4 seconds. 30593 T00401030593 ^x In this paper, MIIS (Medical Image Information System) has been designed and implemented using INGRES RDBMS, which is based on a client/server architecture. The implemented system allows users to register and retrieve patient information, medical images and diagnostic reports. It also provides the function to display these information on workstation windows simultaneously by using the designed menu-driven graphic user interface. The medical image compression/decompression techniques are implemented and integrated into the medical image database system for the efficient data storage and the fast access through the network. 30594 T00401030594 ^x In this paper, computerized BEAM was implemented for the space domain analysis of EEG. Trans-formation from temporal summation to two-dimensional mappings is formed by 4 nearest point inter-polaton method. Methods of representation of BEAM are two. One is dot density method which classify brain electrical potential 9 levels by dot density of gray levels and the other is colour method which classify brain electrical 12 levels by red-green colours. In this BEAM, instantaneous change and average energy distribution over any arbitrary time interval of brain electrical activity could be observed and analyzed easily. In the frequency domain, the distribution of energy spectrum of a special band can easily be distinguished normality and abnormality. 30608 T00401030608 ^x Laboratory information system (LIS) is a key tool to manage laboratory data in clinical pathology. Our department has developed an information system for routine hematology using down-sized computer system. We have used an IBM 486 compatible PC with 16MB main memory, 210 MB hard disk drive, 9 RS-232C port and 24 pin dot printer. The operating system and database management system were SCO UNIX and SCO foxbase, respectively. For program development, we used Xbase language provided by SCO foxbase. The C language was used for interface purpose. To make the system use friendly, pull-down menu was used. The system connected to our hospital information system via application program interface (API), so the information related to patient and request details is automatically transmitted to our computer. Our system interfaced with fwd complete blood count analyzers(Sysmex NE-8000 and Coulter STKS) for unidirectional data tansmission from analyzer to computer. The authors suggests that this system based on down-sized computer could provide a progressive approach to total LIS based on local area network, and the implemented system could serve as a model for other hospital's LIS for routine hematology. 30609 T00401030609 ^x To develop an artificial bone substitute that is gradually degraded and replaced by the regenerated natural bone, the authors designed a composite that is consisted of calcium phosphate and collagen. To use as the structural matrix of the composite, collagen was purified from human umbilical cord. The obtained collagen was treated by pepsin to remove telopeptides, and finally, the immune-free atelocollagen was produced: The cross linked atelocollagen was highly resistant to the collagenase induced collagenolysis. The cross linked collagen demonstrated an improved tensile strength. 30618 T00401030618 ^x This paper is a study on the design of adptive filter for QRS complex detection. We propose a simple adaptive algorithm to increase capability of noise cancelation in QRS complex detection with two stage adaptive filter. At the first stage, background noise is removed and at the next stage, only spectrum of QRS complex components is passed. Two adaptive filters can afford to keep track of the changes of both noise and QRS complex. Each adaptive filter consists of prediction error filter and FIR filter The impulse response of FIR filter uses coefficients of prediction error filter. The detection rates for 105 and 108 of MIT/BIH data base were 99.3% and 97.4% respectively. 30619 T00401030619 ^x To develop an artificial bone substitute that is gradually degraded and replaced by the regenerated natural bone, the authors designed and produced a composite that is consisted of calcium phosphate and collagen. Human umbilical cord origin pepsin treated type I atelocollagen was used as the structural matrix, by which sintered or non-sintered carbonate apatite was encapsulated to form an inorganic-organic composite. With cross linking atelocollagen by UV ray irradiation, the resistance to both compressive and tensile strength was increased. Collagen degradation by the collagenase induced collagenolysis was also decreased. 30620 T00401030620 ^x We have developed a monoleaflet polymer valve as an inexpensive and viable alternative, especially for short-term use in the ventricular assist device or total artificial heart. The frame and leaflet of the polymer valve were made from polyurethane, To evaluate the hemodynamic performance of the polymer valve a comparative study of flow dynamics past a polymer valve and a St. Jude Medical prosthetic valve under physiological pulsatile flow conditions in vitro was made. Comparisons between the valves were made on the transvalvular pressure drop, regurgitation volume and maximum valve opening area. The polymer valve showed smaller regurgitation volume and transvalvular pressure drop compared to the mechanical valve at higher heart rate. The results showed that the functional characteristics of the polymer valve compared favorably with those of the mechanical valve at higher heart rate. 30621 T00401030621 ^x Explosive evaporative removal process of biological tissue by absorption of a CW laser has been simulated by using gelatin and a multimode Nd:YAG laser. Because the point of maximun temperature of laser-irradiated gelatin exists below the surface due to surface cooling, evaporation at the boiling temperature is made explosively from below the surface. The important parameters of this process are the conduction loss to laser power absorption (defined as the conduction-to-laser power parameter, Nk), the convection heat transfer at the surface to conduction loss (defined as Bi), dimensionless extinction coefficient (defined as Br.), and dimensionless irradiation time (defined as Fo). Dependence of Fo on Nk and Bi has been observed by experiment, and the results have been compared with the numerical results obtained by solving a 2-dimensional conduction equation. Fo and explosion depth (from the surface to the point of maximun temperature) are increased when Nk and Bi are increased.To find out the minimum laser power for explosive evaporative removal process, steady state analysis has been also made. The limit of Nk to induce evaporative removal, which is proportional to the inverse of the laser power, has been obtained. 30622 T00401030622 ^x N1 and N2 gross neural action potentials were measured from the round window of the guinea pig cochlea at the onset of the acoustic stimuli. N1-N2 audiograms were made by means of regulating stimulant intensities in order to produce constant N1-N2 potentials as criteria for different input tone pip frequencies. The lowest threshold was measured with an input tone pip I5 dB SPL in intensity and 12 KHz in frequency when the animal was in normal physiological condition. The procedure of experimental measurements is explained in detail. This experimental approach is very useful for the investigation of the Cochlear function. Both noN1inear and active functions of the Cochlea can be monitored by N1-N2 audiograms. 30623 T00401030623 ^x In electrical impedance tomography(EIT), we use boundary current and voltage measurements toprovide the information about the cross-sectional distribution of electrical impedance or resistivity. One of the major problems in EIT has been the inaccessibility of internal voltage or current data in finding the internal impedance values. We propose a new image reconstruction method using internal current density data measured by NMR. We obtained a two-dimensional current density distribution within a phantom by processing the real and imaginary MR images from a 4.77 NMR machine. We implemented a resistivity mage reconstruction algorithm using the finite element method and sensitivity matrix. We presented computer simulation results of the mage reconstruction algorithm and furture direction of the research. 30624 T00401030624 ^x A new method of digital image analysis technique for discrimination of cancer cell was presented in this paper. The object image was the Thyroid eland cells image that was diagnosed as normal and abnormal (two types of abnormal: follicular neoplastic cell, and papillary neoplastic cell), respectively. By using the proposed region segmentation algorithm, the cells were segmented into nucleus. The 16 feature parameters were used to calculate the features of each nucleus. A9 a consequence of using dominant feature parameters method proposed in this paper, discrimination rate of 91.11% was obtained for Thyroid Gland cells. 30625 T00401030625 ^x An electrical stimulator was designed to induce locomotion for paraplegic patients caused by central nervous system injury. Optimal stimulus parameters, which can minimize muscle fatigue and can achieve effective muscle contraction were determined in slow and fast muscles in Sprague-Dawley rats. Stimulus patterns of our stimulator were designed to simulate electromyographic activity monitored during locomotion of normal subjects. Muscle types of the lower extremity were classified according to their mechanical property of contraction, which are slow muscle (msoleus m.) and fast muscle (medial gastrocneminus m., rectus femoris m., vastus lateralis m.). Optimal parameters of electrical stimulation for slow muscles were 20 Hz, 0.2 ms square pulse. For fast muscle, 40 Hz, 0.3 ms square pulse was optimal to produce repeated contraction. Higher stimulus intensity was required when synergistic muscles were stimulated simultaneously than when they were stimulated individually. Electrical stimulation for each muscle was designed to generate bipedal locomotion, so that individual muscles alternate contraction and relaxation to simulate stance and swing phases. Portable electrical stimulator with 16 channels built in microprocessor was constructed and applied to paraplegic patients due to lumbar cord injury. The electrical stimulator restored partially gait function in paraplegic patients. 30626 T00401030626 ^x Two-Dimensional modelling of the Cochlear biomechanics is presented in this paper. The Laplace partial differential equation which represents the fluid mechanics of the Cochlea has been transformed into two-dimensional electrical transmission line. The procedure of this transformation is explained in detail. The comparison between one and two dimensional models is also presented. This electrical modelling of the basilar membrane (BM) is clearly useful for the next approach to the further. Development of active elements which are essential in the producing of the sharp tuning of the BM. This paper shows that two-dimension model is qualitatively better than one-dimensional model both in amplitude and phase responses of the BM displacement. The present model is only for frequency response. However because the model is electrical, the two-dimensional transmission line model can be extended to time response without any difficult. 30627 T00401030627 ^x A method has been proposed for the fully automatic detection of left ventricular endocardial boundary in 2D short axis echocardiogram using geometric model. The procedure has the following three distinct stages. First, the initial center is estimated by the initial center estimation algorithm which is applied to decimated image. Second, the center estimation algorithm is applied to original image and then best-fit elliptic model estimation is processed. Third, best-fit boundary is detected by the cost function which is based on the best-fit elliptic model. The proposed method shows effective result without manual intervention by a human operator. 30628 T00401030628 ^x The intelligent trajectory control method that controls moving direction and average velocity for a prosthetic arm is proposed by pattern recognition and force estimations using EMG signals. Also, we propose the real time trajectory planning method which generates continuous accelleration paths using 3 stage linear filters to minimize the impact to human body induced by arm motions and to reduce the muscle fatigue. We use combination of MLP and fuzzy filter for pattern recognition to estimate the direction of a muscle and Hogan's method for the force estimation. EMG signals are acquired by using a amputation simulator and 2 dimensional joystick motion. The simulation results of proposed prosthetic arm control system using the EMf signals show that the arm is effectively followed the desired trajectory depended on estimated force and direction of muscle movements. 30638 T00401030638 ^x A new neural network architecture for the recognition of patterns from images is proposed, which is partially based on the results of physiological studies. The proposed network is composed of multi-layers and the nerve cells in each layer are connected by spatial filters which approximate receptive fields in optic nerve fields. In the proposed method, patterns recognition for complicated images is carried out using global features as well as local features such as lines and end-points. A new generating method of matched filers representing global features is proposed in this network. 30659 T00401030659 ^x An implementation scheme of the magnetic nerve stimulator using a switching mode power supply is proposed. By using a switching mode power supply rather than a conventional linear power supply for charging high voltage capacitors, the weight and size of the magnetic nerve stimulator can be considerably reduced. Maximum output voltage of the developed magnetic nerve stimulator using the switching mode power supply is 3, 000 volts and switching time is about 100 msec. Experimental results or human nerve stimulations using the developed stimulator are presented. 30768 T00401030768 ^x 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 SpO2 with Plethysmograph.SpO2 with Plethysmograph.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
• /
• 한국우주과학회 1993년도 한국우주과학회보 제2권2호
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• pp.17-17
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• 1993

The wall shear stress in the vicinity of end-to end anastomoses under steady flow conditions was measured using a flush-mounted hot-film anemometer(FMHFA) probe. The experimental measurements were in good agreement with numerical results except in flow with low Reynolds numbers. The wall shear stress increased proximal to the anastomosis in flow from the Penrose tubing (simulating an artery) to the PTFE: graft. In flow from the PTFE graft to the Penrose tubing, low wall shear stress was observed distal to the anastomosis. Abnormal distributions of wall shear stress in the vicinity of the anastomosis, resulting from the compliance mismatch between the graft and the host artery, might be an important factor of ANFH formation and the graft failure. The present study suggests a correlation between regions of the low wall shear stress and the development of anastomotic neointimal fibrous hyperplasia(ANPH) in end-to-end anastomoses. 30523 T00401030523 ^x Air pressure decay(APD) rate and ultrafiltration rate(UFR) tests were performed on new and saline rinsed dialyzers as well as those roused in patients several times. C-DAK 4000 (Cordis Dow) and CF IS-11 (Baxter Travenol) reused dialyzers obtained from the dialysis clinic were used in the present study. The new dialyzers exhibited a relatively flat APD, whereas saline rinsed and reused dialyzers showed considerable amount of decay. C-DAH dialyzers had a larger APD(11.70${\pm}$1.32mmHg/min)compared to CF dialyzers(4.32${\pm}$0.55mmHg/min)(p<0.05). However, there was no observable difference in the UFR between the two dialyzers. Neither APD nor UFR showed any significant increase with an increasing number of reuses for up to more than 20reuses. A substantial number of failures observed in APD(larger than 20mmHe/min)on the reused dialyzers(2 out of 40 CP and S out 26 C-DAK) were attributed to the Possible damage on the fibers. The CF 15-11 HFDs which failed APD test did not show changes in the UFR compared to normal dialyzers indicating that APD is a more sensitive test than UFR test to evaluate the integrity of the fibers. 30527 T00401030527 ^x For quantitative measurement of reflected light from a clinical diagnostic strip, a prototype old reflectance photometer was designed. The strip loader and cassette were made to obtain more accurate reflectance parameters. The strip was illuminated at 45˚c through optical fiber and the intensity of reflected light was determined at rectanguLat angle using a photodiode. The kubelka-munk coefficient and reflection optical density were determined ar four different wavelengths(500,550,570 and 610nm) for blood glucose strip. For higher concentration than 300mg/41 about glucose, a saturation state of abforbance was observed at 500,550 and 570nm. The correlation between glucose concentration and parameters was the best at 610nm. 30535 T00401030535 ^x Radiation-induced fibrosarcoma tumors were grown on the flanks of C3H mice. The mice were divided into two groups. One group was injected with Photofrin II, intravenously (2.5mg/kg body weight). The other group received no Photofrin II. Mice from both groups were irradialed for approximately 15 minutes at 100,300, or 500 mW/cm2 with the argon (488nm/514.5 nm), dye(628nm) and gold vapor (pulsed 628 nm) laser light. A photosensitizer behaved as an added absorber. Under our experimental conditions, the presence of Photolfrin II increased surface temperature by at least 40% and the temperature rise due to 300 mW/cm2 irradiation exceeded values for hyperthermia. Light and temperature distributions with depth were estimated by a computer model. The model demonstrated the influence of wavelength on the thermal process and proved to be a valuable tool to investigate internal temperature rise. 30536 T00401030536 ^x We investigated the structural geometry of thirty-eight Korean femurs. The purpose of this study is to identify major geometrical differences between Korean femurs 3nd others that we believe belong to Caucasians so that we would be able to get insights into the femoral component design that fits Asians including Koreans. We utilized computerized tomography (CT) images of femurs extracted from cadavers. The CT images were transformed into bitmap data by using a film scanner, and then analyzed by using a commercially available software called Image v.1.0 and a Macintosh IIci computer.The resulting data were compared with already published data. The major results show that the geometry of the Korean femurs is significantly different from that of Caucasians: (1) the anteversion angle and the canal flare index are greater by the amount of approximately 8˚ and 0.5, respectively, (2) the shape of the isthmus cross section is more round, and (3) the distance between the teaser trochanter and the proximal border of the isthmus is shelter by about 15 mm. The results suggested that the femoral component suitable for Asians should be different from the currently-used components designed and manufactured mostly by European or American companies. 30537 T00401030537 ^x It is well known that nonlinear propagation characteristics of the wave in the tissue may give very useful information for the medical diagnoisis. In this paper, a new method to detect nonlinear propagation characteristics of the internal vibration in the tissue for the low frequency mechanical vibration by using bispectral analysis is proposed. In the method, low frequency vibration of f0( = 100Hz) is applied on the surface of the object, and the waveform of the internal vibration x (t) is measured from Doppler frequency modulation of silmultaneously transmitted probing ultrasonic waves. Then, the bispectra of the signal x (t) at the frequencies (f0, f0) and (f0, 2f0) are calculated to estimate the nonlinear propagation characteristics as their magnitude ratio, w here since bispectrum is free from the gaussian additive noise we can get the value with high S/N. Basic experimental system is constructed by using 3.0 MHz probing ultrasonic waves and the several experiments are carried out for some phantoms. Results show the superiority of the proposed method to the conventional method using power spectrum and also its usefulness for the tissue characterization. 30541 T00401030541 ^x This paper describes the implementation of a computerized radial pulse diagnosis by aids of a clinical expert. On this base, we composed of the radial pulse diagnosis system in korean traditional medicine. The system composed of a radial pulse wave detection system and a radial pulse diagnosis system. With a detection system, we detected Inyoung and Cheongu radial pulse wave and processed it. Then, we have got the characteristic parameters of radial pulse wave and also quantified that according to the method of Inyoung-Cheongu Comparison Radial Pulse Diagnosis. We defined the jugement standard of radial pulse diagnosis system and then we confirmed the possibility for realization of automatic radial pulse diagnosis in korean traditional medicine. 30545 T00401030545 ^x Microspheres are expected to be applied to biomedical areas such as solid-phase immunoassays, drug delivery systems, immunomagnetic cell separation. To synthesize microspheres for biomedical application, "two stage shot growth method" was developed. The uniformity ratio of synthesized microspheres was always smaller than 1.05. And the surface charge density (or the number of ionizable functional groups) of the microspheres synthesized by "two stage shot growth method" was 6~13 times higher than that of the microspheres synthesized by conventional seeded batch copolymerization. As a previous step for biomedical application, adsorption experiments of bovine albumin on microspheres were carried out under various conditions. The maximum adsorbed amount was obtained in the neighborhood of pH 4.5. Isoelectric point of bovine albumin is pH 5.0, so experimental result shows that it shifted to acid area. The adsorption isotherm was obtained, the plateau region was always reached at 2.Og/L (bulk concentration of bovine albumin).The effect of the kind and the amount of surface functional group was also examined. 30575 T00401030575 ^x A medical image workstation was developed using multimedia technique. The system based on PC-486DX was designed to acquire medical images produced by medical imaging instruments and related audio information, that is, doctors' reporting results. Input information was processed and analyzed, then the results were presented in the form of graph and animation. All the informations of the system were hierarchically related with the image as the apex. Processing and analysis algorithms were implemented so that the diagnostic accuracy could be improved. The diagnosed information can be transferred for patient diagnosis through LAN(local area network). 30592 T00401030592 ^x In the conventional infrared imaging system, complex infrared lens systems are usually used for directing collimated narrow infrared beams into the high speed 2-dimensional optic scanner. In this paper, a simple reflective infrared optic system with a 2-dimensional optic scanner is proposed for the realization of medical infrared thermography system. It has been experimentally proven that the intfrared thermography system composed of the proposed optic system has the temperature resolution of 0.1˚c under the spatial resolution of lmrad, the image matrix size of 256 X 240, and tile imaging time of 4 seconds. 30593 T00401030593 ^x In this paper, MIIS (Medical Image Information System) has been designed and implemented using INGRES RDBMS, which is based on a client/server architecture. The implemented system allows users to register and retrieve patient information, medical images and diagnostic reports. It also provides the function to display these information on workstation windows simultaneously by using the designed menu-driven graphic user interface. The medical image compression/decompression techniques are implemented and integrated into the medical image database system for the efficient data storage and the fast access through the network. 30594 T00401030594 ^x In this paper, computerized BEAM was implemented for the space domain analysis of EEG. Trans-formation from temporal summation to two-dimensional mappings is formed by 4 nearest point inter-polaton method. Methods of representation of BEAM are two. One is dot density method which classify brain electrical potential 9 levels by dot density of gray levels and the other is colour method which classify brain electrical 12 levels by red-green colours. In this BEAM, instantaneous change and average energy distribution over any arbitrary time interval of brain electrical activity could be observed and analyzed easily. In the frequency domain, the distribution of energy spectrum of a special band can easily be distinguished normality and abnormality. 30608 T00401030608 ^x Laboratory information system (LIS) is a key tool to manage laboratory data in clinical pathology. Our department has developed an information system for routine hematology using down-sized computer system. We have used an IBM 486 compatible PC with 16MB main memory, 210 MB hard disk drive, 9 RS-232C port and 24 pin dot printer. The operating system and database management system were SCO UNIX and SCO foxbase, respectively. For program development, we used Xbase language provided by SCO foxbase. The C language was used for interface purpose. To make the system use friendly, pull-down menu was used. The system connected to our hospital information system via application program interface (API), so the information related to patient and request details is automatically transmitted to our computer. Our system interfaced with fwd complete blood count analyzers(Sysmex NE-8000 and Coulter STKS) for unidirectional data tansmission from analyzer to computer. The authors suggests that this system based on down-sized computer could provide a progressive approach to total LIS based on local area network, and the implemented system could serve as a model for other hospital's LIS for routine hematology. 30609 T00401030609 ^x To develop an artificial bone substitute that is gradually degraded and replaced by the regenerated natural bone, the authors designed a composite that is consisted of calcium phosphate and collagen. To use as the structural matrix of the composite, collagen was purified from human umbilical cord. The obtained collagen was treated by pepsin to remove telopeptides, and finally, the immune-free atelocollagen was produced: The cross linked atelocollagen was highly resistant to the collagenase induced collagenolysis. The cross linked collagen demonstrated an improved tensile strength. 30618 T00401030618 ^x This paper is a study on the design of adptive filter for QRS complex detection. We propose a simple adaptive algorithm to increase capability of noise cancelation in QRS complex detection with two stage adaptive filter. At the first stage, background noise is removed and at the next stage, only spectrum of QRS complex components is passed. Two adaptive filters can afford to keep track of the changes of both noise and QRS complex. Each adaptive filter consists of prediction error filter and FIR filter The impulse response of FIR filter uses coefficients of prediction error filter. The detection rates for 105 and 108 of MIT/BIH data base were 99.3% and 97.4% respectively. 30619 T00401030619 ^x To develop an artificial bone substitute that is gradually degraded and replaced by the regenerated natural bone, the authors designed and produced a composite that is consisted of calcium phosphate and collagen. Human umbilical cord origin pepsin treated type I atelocollagen was used as the structural matrix, by which sintered or non-sintered carbonate apatite was encapsulated to form an inorganic-organic composite. With cross linking atelocollagen by UV ray irradiation, the resistance to both compressive and tensile strength was increased. Collagen degradation by the collagenase induced collagenolysis was also decreased. 30620 T00401030620 ^x We have developed a monoleaflet polymer valve as an inexpensive and viable alternative, especially for short-term use in the ventricular assist device or total artificial heart. The frame and leaflet of the polymer valve were made from polyurethane, To evaluate the hemodynamic performance of the polymer valve a comparative study of flow dynamics past a polymer valve and a St. Jude Medical prosthetic valve under physiological pulsatile flow conditions in vitro was made. Comparisons between the valves were made on the transvalvular pressure drop, regurgitation volume and maximum valve opening area. The polymer valve showed smaller regurgitation volume and transvalvular pressure drop compared to the mechanical valve at higher heart rate. The results showed that the functional characteristics of the polymer valve compared favorably with those of the mechanical valve at higher heart rate. 30621 T00401030621 ^x Explosive evaporative removal process of biological tissue by absorption of a CW laser has been simulated by using gelatin and a multimode Nd:YAG laser. Because the point of maximun temperature of laser-irradiated gelatin exists below the surface due to surface cooling, evaporation at the boiling temperature is made explosively from below the surface. The important parameters of this process are the conduction loss to laser power absorption (defined as the conduction-to-laser power parameter, Nk), the convection heat transfer at the surface to conduction loss (defined as Bi), dimensionless extinction coefficient (defined as Br.), and dimensionless irradiation time (defined as Fo). Dependence of Fo on Nk and Bi has been observed by experiment, and the results have been compared with the numerical results obtained by solving a 2-dimensional conduction equation. Fo and explosion depth (from the surface to the point of maximun temperature) are increased when Nk and Bi are increased.To find out the minimum laser power for explosive evaporative removal process, steady state analysis has been also made. The limit of Nk to induce evaporative removal, which is proportional to the inverse of the laser power, has been obtained. 30622 T00401030622 ^x N1 and N2 gross neural action potentials were measured from the round window of the guinea pig cochlea at the onset of the acoustic stimuli. N1-N2 audiograms were made by means of regulating stimulant intensities in order to produce constant N1-N2 potentials as criteria for different input tone pip frequencies. The lowest threshold was measured with an input tone pip I5 dB SPL in intensity and 12 KHz in frequency when the animal was in normal physiological condition. The procedure of experimental measurements is explained in detail. This experimental approach is very useful for the investigation of the Cochlear function. Both noN1inear and active functions of the Cochlea can be monitored by N1-N2 audiograms. 30623 T00401030623 ^x In electrical impedance tomography(EIT), we use boundary current and voltage measurements toprovide the information about the cross-sectional distribution of electrical impedance or resistivity. One of the major problems in EIT has been the inaccessibility of internal voltage or current data in finding the internal impedance values. We propose a new image reconstruction method using internal current density data measured by NMR. We obtained a two-dimensional current density distribution within a phantom by processing the real and imaginary MR images from a 4.77 NMR machine. We implemented a resistivity mage reconstruction algorithm using the finite element method and sensitivity matrix. We presented computer simulation results of the mage reconstruction algorithm and furture direction of the research. 30624 T00401030624 ^x A new method of digital image analysis technique for discrimination of cancer cell was presented in this paper. The object image was the Thyroid eland cells image that was diagnosed as normal and abnormal (two types of abnormal: follicular neoplastic cell, and papillary neoplastic cell), respectively. By using the proposed region segmentation algorithm, the cells were segmented into nucleus. The 16 feature parameters were used to calculate the features of each nucleus. A9 a consequence of using dominant feature parameters method proposed in this paper, discrimination rate of 91.11% was obtained for Thyroid Gland cells. 30625 T00401030625 ^x An electrical stimulator was designed to induce locomotion for paraplegic patients caused by central nervous system injury. Optimal stimulus parameters, which can minimize muscle fatigue and can achieve effective muscle contraction were determined in slow and fast muscles in Sprague-Dawley rats. Stimulus patterns of our stimulator were designed to simulate electromyographic activity monitored during locomotion of normal subjects. Muscle types of the lower extremity were classified according to their mechanical property of contraction, which are slow muscle (msoleus m.) and fast muscle (medial gastrocneminus m., rectus femoris m., vastus lateralis m.). Optimal parameters of electrical stimulation for slow muscles were 20 Hz, 0.2 ms square pulse. For fast muscle, 40 Hz, 0.3 ms square pulse was optimal to produce repeated contraction. Higher stimulus intensity was required when synergistic muscles were stimulated simultaneously than when they were stimulated individually. Electrical stimulation for each muscle was designed to generate bipedal locomotion, so that individual muscles alternate contraction and relaxation to simulate stance and swing phases. Portable electrical stimulator with 16 channels built in microprocessor was constructed and applied to paraplegic patients due to lumbar cord injury. The electrical stimulator restored partially gait function in paraplegic patients. 30626 T00401030626 ^x Two-Dimensional modelling of the Cochlear biomechanics is presented in this paper. The Laplace partial differential equation which represents the fluid mechanics of the Cochlea has been transformed into two-dimensional electrical transmission line. The procedure of this transformation is explained in detail. The comparison between one and two dimensional models is also presented. This electrical modelling of the basilar membrane (BM) is clearly useful for the next approach to the further. Development of active elements which are essential in the producing of the sharp tuning of the BM. This paper shows that two-dimension model is qualitatively better than one-dimensional model both in amplitude and phase responses of the BM displacement. The present model is only for frequency response. However because the model is electrical, the two-dimensional transmission line model can be extended to time response without any difficult. 30627 T00401030627 ^x A method has been proposed for the fully automatic detection of left ventricular endocardial boundary in 2D short axis echocardiogram using geometric model. The procedure has the following three distinct stages. First, the initial center is estimated by the initial center estimation algorithm which is applied to decimated image. Second, the center estimation algorithm is applied to original image and then best-fit elliptic model estimation is processed. Third, best-fit boundary is detected by the cost function which is based on the best-fit elliptic model. The proposed method shows effective result without manual intervention by a human operator. 30628 T00401030628 ^x The intelligent trajectory control method that controls moving direction and average velocity for a prosthetic arm is proposed by pattern recognition and force estimations using EMG signals. Also, we propose the real time trajectory planning method which generates continuous accelleration paths using 3 stage linear filters to minimize the impact to human body induced by arm motions and to reduce the muscle fatigue. We use combination of MLP and fuzzy filter for pattern recognition to estimate the direction of a muscle and Hogan's method for the force estimation. EMG signals are acquired by using a amputation simulator and 2 dimensional joystick motion. The simulation results of proposed prosthetic arm control system using the EMf signals show that the arm is effectively followed the desired trajectory depended on estimated force and direction of muscle movements. 30638 T00401030638 ^x A new neural network architecture for the recognition of patterns from images is proposed, which is partially based on the results of physiological studies. The proposed network is composed of multi-layers and the nerve cells in each layer are connected by spatial filters which approximate receptive fields in optic nerve fields. In the proposed method, patterns recognition for complicated images is carried out using global features as well as local features such as lines and end-points. A new generating method of matched filers representing global features is proposed in this network. 30659 T00401030659 ^x An implementation scheme of the magnetic nerve stimulator using a switching mode power supply is proposed. By using a switching mode power supply rather than a conventional linear power supply for charging high voltage capacitors, the weight and size of the magnetic nerve stimulator can be considerably reduced. Maximum output voltage of the developed magnetic nerve stimulator using the switching mode power supply is 3,000 volts and switching time is about 100 msec. Experimental results or human nerve stimulations using the developed stimulator are presented. 30768 T00401030768 ^x 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 SpO2 with Plethysmograph.

• 디자인학연구
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• 제20권3호
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• pp.151-162
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• 2007

모바일 IT와 무선인터넷의 발달에 따라 유선 인터넷 컨텐츠는 무선으로 확장하게 하였으며, 장소기반 관광 정보 서비스가 우선적으로 구축되고 있다. 그러나, 현재 모바일 기기로 서비스되고 있는 대부분의 관광정보는 관광지에 대한 간단한 설명, 교통편, 숙박, 음식점 등 매우 실용적이고 일반적이어서 편리하긴 하지만, 그다지 사용하고 싶은 매력은 없는 정보에 그치고 있다. 본 연구는 향후 유비쿼터스 도시 환경에서 활용 가능한 지역 관광정보를 활용한 LBS 엔터테인먼트 컨텐츠 개발 방안을 도출하기 위한 목적으로 진행되었다. 연구방법으로는 먼저, 지역정보 관련 서비스 및 연구의 국내외 동향을 살펴보고, 이를 기반으로 지역정보를 활용한 LBS 엔터테인먼트 컨텐츠 개발 방향 및 필요한 요소들을 추출하여, 사례 연구로서 부산시 중구 지역의 역사, 문화 컨텐츠 전달을 위한 모바일 투어 게임 "타임트렉"을 개발하였다. "타임트렉"프로토타입은 사용자의 보다 적극적인 참여와 흥미유발을 위해 롤플레잉 스토리 기반 게임과 물리적 장소에서 답을 찾아야 하는 오프라인 퀘스트 게임의 형식을 포함하는 모바일 투어 게임 형태로 구축되었다. 개발된 프로토타입은 제 10회 부산국제영화제 기간 동안투어코스의 한 장소였던 PIFF광장에서 사용자 테스트를 거쳤으며, 테스트 결과를 분석하여 향후 지역정보를 활용한 LBS 엔터테인먼트 컨텐츠 개발 방안을 도출, 제시하였다. 본 연구는 새롭고 재미있는 형태의 지역 역사, 문화 관광 경험을 창출하기 위해 LBS 모바일 기술과 스토리, 게임 등 엔터테인먼트 요소의 결합을 시도함으로써, 관광 산업과 모바일 컨텐츠 산업의 결합이라는 새로운 영역의 개척을 시도하였다는데 그 의의가 있다고 하겠다.순으로 광고물 제어에 유리하다. 그러므로 복합상업건축물 입면계획 시 일방적인 수평요소의 반복은 지양할 필요가 있다. 모서리계획 시에는, 첫째, 2개 이상의 가로와 접하는 건물의 경우 모서리부 광고 효과가 지배적이며 대부분 곡선돌출형이 사용되고 있었다. 그러므로 모서리 저층부를 필로티로 계획하여 보행흐름을 원활하게 하고 대신 입면을 투명하게 하여 간접광고(내부전시) 효과를 유도하는 것이 좋다. 특히 원형모서리는 건물 특화 성격이 강하므로 불가피할 경우 소형 액센트 광고 위치를 미리 벽면으로 할애하는 것이 경관 및 입면계획에 유리한 것으로 분석되었다. 불확실도 해석모형 등의 새로운 기능을 추가하여 제시하였다. 모든 입출력자료는 프로젝트 단위별로 운영되어 data의 관리가 손쉽도록 하였으며 결과를 DB에 저장하여 다른 모형에서도 적용할 수 있도록 하였다. 그리고 HyGIS-HMS 및 HyGIS-RAS 모형에서 강우-유출-하도 수리해석-범람해석 등이 일괄되게 하나의 시스템 내에서 구현될 수 있도록 하였다. 따라서 HyGIS와 통합된 수리, 수문모형은 국내 하천 및 유역에 적합한 시스템으로서 향후 HydroInformatics 구현을 염두에 둔 특화된 국내 수자원 분야 소프트웨어의 개발에 기본 토대를 제공할 것으로 판단된다.았다. 또한 저자들의 임상병리학적 연구결과가 다른 문헌에서 보고된 소아 신증후군의 연구결과와 큰 차이를 보이지 않음을 알 수 있었다. 자극에 차이가 있지 않나 추측되며 이에 관한 추후 연구가 요망된다. 총대장통과시간의 단축은 결장 분절 모두에서 줄어들어 나타났으나 좌측결장 통과시간의 감소 및 이로 인한 이 부위의 통과시간 비율의 저하가 가장 주요하였다. 이러한 결과는 차가운 생수 섭취가

• International Journal of Ocean System Engineering
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• 제2권3호
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• pp.185-194
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• 2012

A Macroscopic combination of two or more distinct materials is commonly referred to as a "Composite Material", having been designed mechanically and chemically superior in function and characteristic than its individual constituent materials. Composite materials are used not only for aerospace and military, but also heavily used in boat/ship building and general composite industries which we are seeing increasingly more. Regardless of the various applications for composite materials, the industry is still limited and requires better fabrication technology and methodology in order to expand and grow. An example of this is that the majority of fabrication facilities nearby still use an antiquated wet lay-up process where fabrication still requires manual hand labor in a 3D environment impeding productivity of composite product design advancement. As an expert in the advanced composites field, I have developed fabrication skills with the use of machinery based on my past composite experience. In autumn 2011, the Korea government confirmed to fund my project. It is the development of a composite sanding machine. I began development of this semi-robotic prototype beginning in 2009. It has possibilities of replacing or augmenting the exhaustive and difficult jobs performed by human hands, such as sanding, grinding, blasting, and polishing in most often, very awkward conditions, and is also will boost productivity, improve surface quality, cut abrasive costs, eliminate vibration injuries, and protect workers from exposure to dust and airborne contamination. Ease of control and operation of the equipment in or outside of the sanding room is a key benefit to end-users. It will prove to be much more economical than normal robotics and minimize errors that commonly occur in factories. The key components and their technologies are a 360 degree rotational shoulder and a wrist that is controlled under PLC controller and joystick manual mode. Development on both of the key modules is complete and are now operational. The Korean government fund boosted my development and I expect to complete full scale development no later than 3rd quarter 2012. Even with the advantages of composite materials, there is still the need to repair or to maintain composite products with a higher level of technology. I have learned many composite repair skills on composite airframe since many composite fabrication skills including repair, requires training for non aerospace applications. The wind energy market is now requiring much larger blades in order to generate more electrical energy for wind farms. One single blade is commonly 50 meters or longer now. When a wind blade becomes damaged from external forces, on-site repair is required on the columns even under strong wind and freezing temperature conditions. In order to correctly obtain polymerization, the repair must be performed on the damaged area within a very limited time. The use of pre-impregnated glass fabric and heating silicone pad and a hot bonder acting precise heating control are surely required.

• 전자공학회논문지
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• 제50권7호
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• pp.122-130
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• 2013

본 논문에서는 주로 고속 디지털 통신시스템 응용을 위해 고해상도, 저전력 및 소면적을 동시에 만족하는 45nm CMOS 공정으로 제작된 4단 파이프라인 구조의 12비트 100MS/s ADC를 제안한다. 입력단 SHA 회로에는 높은 입력 주파수를 가진 신호가 인가되어도 12비트 이상의 정확도로 샘플링할 수 있도록 게이트-부트스트래핑 회로가 사용된다. 입력단 SHA 및 MDAC 증폭기는 요구되는 DC 이득 및 높은 신호스윙을 얻기 위해 이득-부스팅 구조의 2단 증폭기를 사용하며, 넓은 대역폭과 안정적인 신호정착을 위해 캐스코드 및 Miller 주파수 보상기법을 선택적으로 적용하였다. 채널길이 변조현상 및 전원전압 변화에 의한 전류 부정합을 최소화하기 위하여 캐스코드 전류 반복기를 사용하며, 소자의 부정합을 최소화하기 위하여 전류 반복기와 증폭기의 단위 넓이를 통일하여 소자를 레이아웃 하였다. 또한, 제안하는 ADC에는 전원전압 및 온도 변화에 덜 민감한 저전력 기준 전류 및 전압 발생기를 온-칩으로 집적하는 동시에 외부에서도 인가할 수 있도록 하여 다양한 시스템에 응용이 가능하도록 하였다. 제안하는 시제품 ADC는 45nm CMOS 공정으로 제작되었으며 측정된 DNL 및 INL은 각각 최대 0.88LSB, 1.46LSB의 값을 가지며, 동적성능은 100MS/s의 동작속도에서 각각 최대 61.0dB의 SNDR과 74.9dB의 SFDR을 보여준다. 시제품 ADC의 면적은 $0.43mm^2$ 이며 전력소모는 1.1V 전원전압 및 100MS/s 동작속도에서 29.8mW이다.

• 한국의학물리학회지:의학물리
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• 제26권4호
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• pp.215-222
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• 2015

본 연구에서는 단일 비산란 그리드 및 다색광 x-선원을 이용하여 위상대조 x-선 영상을 용이하게 구현할 수 있는 새로운 방법을 제안한다. 제안된 신기법의 개념 입증을 위해 집속형 선형 그리드(200 lines/inch 선 밀도), 마이크로 초점 x-선관(${\sim}5{\mu}m$ 초점크기), CMOS형 평판형 검출기($48{\mu}m$ 픽셀 크기)로 실험장치를 구성하였으며, 한 번의 x-선 촬영($90kV_p$, 0.1 mAs)으로 감약대조 x-선 영상과 향상된 가시성을 지진 산란 x-선 영상 및 차분 위상대조 x-선 영상을 Fourier변조복원 기법을 적용하여 성공적으로 분리 획득하였다. 더 나아가, 감약대조 x-선 영상과 산란 x-선 영상을 합성함으로써 일반 감약대조 x-선 영상에서는 명확하게 볼 수 없는 샘플의 미세 구조를 보다 선명하게 나타냄을 확인하였다. 본 논문에서 제안한 단일 비산란 그리드 기반 위상대조 x-선 영상화 기법은 실험 구성 및 절차가 단순하고 새로운 대조도에 기반한 산란 및 위상대조 x-선 영상을 동시에 제공하기 때문에 차세대 x-선 영상화 신기법으로 다양한 응용분야에서 용이하게 적용될 수 있을 것으로 전망한다.

• 대한전자공학회논문지SD
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• 제46권3호
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• pp.60-68
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• 2009

본 논문에서는 HDTV와 같이 고해상도 및 고속의 동작을 동시에 요구하는 고화질 영상시스템 응용을 위한 10비트 200MS/s 65nm CMOS ADC를 제안한다. 제안하는 ADC는 고속 동작에서 저 전력 소면적 구현에 적합한 4단 파이프라인 구조를 기반으로 설계되었으며, 입력단 SHA 회로에서는 1.2V의 낮은 단일 전원 전압에서도 높은 입력 신호를 처리하기 위해 4개의 커패시터를 기반으로 설계하여 $1.4V_{p-p}$의 입력 신호를 ADC 내부 회로에서는 $1.0V_{p-p}$으로 낮추어 사용할 수 있도록 하였다. 또한 높은 전압이득을 갖는 증폭기를 필요로 하는 SHA와 MDAC1은 출력 임피던스가 감소하는 65nm CMOS 공정의 제약 사항을 극복하기 위해 통상적인 2단 증폭기 대신 3단 증폭기 구조를 기반으로 설계하였으며 200MS/s 높은 동작 속도를 고려하여 RNMC 및 multipath 주파수 보상기법을 추가하여 설계하였다. 전력 소모 최소화를 위해 스위치 기반의 바이어스 전력최소화 기법을 sub-ranging flash ADC에 적용하였고, 기준 전류 및 전압 발생기를 온-칩으로 집적하는 동시에 외부에서도 인가할 수 있도록 하여 시스템 응용에 따라 선택적으로 사용할 수 있도록 하였다. 제안하는 시제품 ADC는 65nm CMOS 공정으로 제작되었으며, 측정된 DNL 및 INL은 10비트 해상도에서 각각 최대 0.19LSB, 0.61LSB 수준을 보이며, 동적 성능으로는 150MS/s와 200MS/s의 동작 속도에서 각각 54.4dB, 52.4dB의 SNDR과 72.9dB 64.8dB의 SFDR을 보여준다. 시제품 ADC의 칩 면적은 $0.76mm^2$이며, 1.2V 전원 전압과 200MS/s의 동작 속도에서 75.6mW의 전력을 소모한다.

• 대한전자공학회논문지SD
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• 제46권3호
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• pp.75-85
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• 2009

본 논문에서는 two-carrier W-CDMA 응용과 같이 고해상도, 저전력 및 소면적을 동시에 요구하는 3G 통신 시스템 응용을 위한 13비트 100MS/s 0.13um CMOS ADC를 제안한다. 제안하는 ADC는 4단 파이프라인 구조를 사용하여 고해상도와 높은 신호처리속도와 함께 전력 소로 및 면적을 최적화하였다. 입력 단 SHA 회로에는 면적 효율성을 가지멸서 고속 고해상도로 동작하는 게이트-부트스트래핑 회로를 적용하여 1.0V의 낮은 전원 전압동작에서도 신호의 왜곡없이 Nyquist 대역 이상의 입력 신호를 샘플링할 수 있도록 하였다. 입력 단 SHA 및 MDAC에는 낮은 임피던스 기반의 캐스코드 주파수 보상 기법을 적용한 2단 증폭기 회로를 사용하여 Miller 주파수 보상 기법에 비해 더욱 적은 전력을 소모하면서도 요구되는 동작 속도 및 안정적인 출력 조건을 만족시키도록 하였으며, flash ADC에 사용된 래치의 경우 비교기의 입력 단으로 전달되는 킥-백 잡음을 줄이기 위해 입력 단과 출력 노드를 클록 버퍼로 분리한 래치 회로를 사용하였다. 한편, 제안하는 시제품 ADC에는 기존의 회로와는 달리 음의 론도 계수를 갖는 3개의 전류만을 사용하는 기준 전류 및 전압 발생기를 온-칩으로 집적하여 잡음을 최소화하면서 시스템 응용에 따라 선택적으로 다른 크기의 기준 전압 값을 외부에서 인가할 수 있도록 하였다. 제안하는 시제품 ADC는 0.13um 1P8M CMOS 공정으로 제작되었으며, 측정된 DNL 및 INL은 13비트 해상도에서 각각 최대 0.70LSB, 1.79LSB의 수준을 보이며, 동적 성능으로는 100MS/s의 동작 속도에서 각각 최대 64.5dB의 SNDR과 78.0dB의 SFDR을 보여준다. 시제품 ADC의 칩 면적은 $1.22mm^2$이며, 1.2V 전원 전압과 100MS/s의 동작 속도에서 42.0mW의 전력을 소모하여 0.31pJ/conv-step의 FOM을 갖는다.

• 한국조경학회지
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• 제42권5호
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• pp.134-147
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• 2014

일제강점기 도입된 유원지는 새로운 행락활동이 조직되는 장이었으며, 대규모 사적 공간인 동시에 새로운 유형의 공공 공간으로 발전해갔다. 이에 본 연구에서 당시 대표적 유원지였던 월미도유원지를 통해 유원지의 경관과 수용, 행락 문화의 변화를 고찰해 보았다. 당시 월미도는 수목과 어우러진 이국적 건물, 해수욕장, 임해학교, 공설운동장, 동물원 등 서구 및 일본 유원지의 요소들이 섬 곳곳에 배치되어 종합적인 오락/놀이 공간이 되었다. 일제강점기 경성과 경인선으로 연결되었던 월미도유원지는 당시 대표적 행락지로 떠오르면서, 행락 문화의 대중화와 상품화 과정을 보여준다. 행락의 대중화 과정을 보면, 유원지를 통해 수려한 풍경을 찾아 여가를 즐기는 행락 활동이 다양한 계층으로 확산되는 양상을 확인할 수 있다. 사회적으로는 신분제가 철폐되고, 유원지의 이용은 비용만 지불하면 누구라도 이용할 수 있었고, 그 이용요금도 다양하였으므로, 유원지에서의 행락은 남녀노소, 조선인과 일본인 등 계층의 구분이 점차 사라져갔다. 또한 유원지는 서구적인 취미-스포츠 활동이 펼쳐지는 공간이었으며, 여름학교와 각종 운동경기가 열리면서 집단적이고 역동적인 활동을 보편화하는 매개가 된다. 동시에, 유흥시설과 복합되어 기존의 사회적 규범에서 일탈하는 공간이 되기도 했다. 행락의 상품화는 인위적 환경 속 인공적 오락문화의 형태로 이루어졌다. 첫째, 인위적으로 경관을 조성하고, 이를 매개로 '매혹적인 여름 휴양지', '물나라' 등 낙원이라는 장소이미지를 만들어낸다. 이는 관광을 통해 경제적 이윤을 창출하고, 지역개발을 꾀하려는 식민당국과 철도회사, 유원회사의 의도가 결합한 결과이다. 둘째, 자연을 배경으로 한 인위적인 스펙터클을 조성한다. 월미도 유원지에는 다양한 양식의 건물들이 조합되어 선진화되고, 이국적인 이미지를 만들어낸다. 특히 방파제나 아케이드 등의 인공물들은 자연과 군중을 새로운 시점에서 조망할 수 있도록 하여 새로운 볼거리를 창출했다. 셋째, 유원지는 주어진 용도와 이용방법을 벗어남 없이 따르는 수동적인 이용자를 등장시켰다. 이처럼 유원지가 역동적인 활동을 지원하는 공간으로 조성되면서 현재 관광 단지나 놀이공원, 테마파크 등의 대중적 오락 공간의 원형적 모습을 확인할 수 있다.

• 수산해양기술연구
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• 제35권2호
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• pp.161-169
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• 1999

본 논문은 개량식 정치망내에 방류한 체장 30 cm의 부시리, Seriola aureovittata의 유영행동 및 탈출행동을 텔레메트리기법으로 추적하고, 그 결과를 기술한 것이다. 압력센서를 내장한 초음파 핑거를 부착시켜 방류한 시험어의 행동은 장기선 방식의 어군행동 원격감시 시스템을 사용하여 추적하였다. 수신점의 수는 3개였고, 초음파 핑거의 3차원 위치는 쌍곡선위치결정법으로 구한 평면좌표 x, y와 압력센서로 관측한 심도 z를 사용하여 구하였다. 실험에서 얻은 결과는 다음과 같다. 1. 시험어는, 방류직후,15 m 깊이까지 급잠하였다가 수면가까이 부상하는 행동을 보였고, 방류직후부터 5분간 측정한 평균 유영속도는 0.87 m/sec를 나타내었다. 2. 시간이 경과함에 따라 시험어의 유영속도는 점차 느려지는 경향을 나타내었고, 방류후 1시간정도 경과한 때부터는 주로 헛통쪽 비탈그물 부근에서 섬도 1～7 m 에 머물면서 탈출을 시도하는 행동을 보였다. 이 시간대의 평균 유영속도는 0.52 m/sec로 나타났다. 3. 양망을 시작하여 25분정도가 경과하기까지는 시험어가 1단계 비탈그물에서 벗어나 2단계 원통쪽으로 도피하면서 1단계 원통그물의 구석까지 빠른 속도로 왕복하는 수평 유영행동을 보였고, 수직적으로는 심도 20 m 까지 하강하였다가 다시 표층으로 부상하는 행동을 나타내었다. 그 이후 시간에는 양망 중임에도 불구하고 다시 1 단계 비탈그물 부근에 머물면서 헛통쪽으로 탈출하고자하는 행동을 나타내었고, 양망 중에 헛통으로 탈출한 것으로 나타났다. 양망 초기의 평균 유영속도는 양망직전의 유영속도에 비하여 38.5 % 증가한 0.72 m/sec (체장의 2.4 배)였으며, 방류 후 1단계 원통을 탈출할 때까지 측정한 평균 유영속도는 0.67 m/sec로 체장대비 2.2배의 빠르기였다.