• 한국ITS학회 논문지
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• 제19권6호
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• pp.163-179
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• 2020

플랫폼 기반의 택시서비스의 확대로 이용자의 이동성 및 편의성이 개선되고 있으나, 수익성의 문제로 공급 취약지역이 발생할 것으로 예상된다. 이에 따라 본 연구에서는 대중교통이 종료되는 심야시간을 중심으로 수요 공급의 불균형에 따른 택시 서비스의 공간적 취약성을 분석하였다. Hot-spot 분석결과 승차대비 공차량 및 승차대비 하차량의 경우 도시 외곽지역 및 주거밀집 지역에서 높게 도출되었고, 반대로 도심 및 부도심에서 낮게 나타나는 것을 확인하였다. 중심성 분석 결과 또한 Hot-spot 분석결과와 유사한 패턴으로 분석되었다. 이는 운전자의 관점에서 내향 대비 외향중심성이 낮은 지역은 다음 영업에 한계로 간접승차 거부의 문제가 발생할 수 있으며, 승객의 입장에서는 대기시간 증가로 이어질 것으로 예상된다. 이에 향후 수요공급의 불일치에 의한 공간적 취약성 개선이 필요할 것으로 판단되며, 본 연구의 결과를 기초자료로 활용 할 수 있을 것으로 기대된다.

• 한국지반공학회논문집
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• 제23권7호
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• pp.5-16
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• 2007

수중 산사태의 관측 및 조사는 산사태의 메커니즘의 이해, 설계 및 시공의 유용성, 그리고 손실 감소에 도움을 준다. 본 논문은 실험실 조건의 수중 산사태를 확인하기 위하여 전기저항, 초음파 반사 이미지, 그리고 전단파 토모그래피의 3가지 고해상도 지구물리탐사기법을 수행하였다. 전기저항 탐침에 의한 흙의 전기저항 프로파일은 밀리미터 단위의 해상도로 흙의 공간적 분포 평가를 위한 자세한 정보를 제공해 준다. 임피던스가 다른 물질의 경계면부터의 반사 자료에 의한 초음파 반사 이미지는 밀리미터 단위의 해상도로 사면 형상 및 시료 층상을 탐지해 낼 수 있다. 전단파 이동 시간으로부터 얻어지는 경계 정보의 역산에 의한 픽셀단위 수중 산사태의 이미지를 만들 수 있다. 실험결과 초음파 이미지와 전기저항은 서로 보완적인 정보를 제공할 수 있으며, 전단파 토모그래피 이미지와 연합하여 수중 산사태의 3차원 이미지를 얻을 수 있다. 본 연구는 지구물리탐사기법들이 수중 산사태 및 해안의 공간적 분포의 탐지에 효과적인 기법이 될 수 있음을 보여준다.

• 토지주택연구
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• 제14권4호
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• pp.17-37
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• 2023

전체 주택 시장에서 보증부 월세시장이 차지하는 비중은 전세 지분을 잠식하며 지난 30년 간 지속적으로 증가하여(1990년 8.2% → 2020년 21.0%) 2.6배로 확대되었다. 월세 부담 분포는 공공임대 월세 지원의 확대와 고가 월세의 등장으로 월세시장 재편으로 이어지고 있다. 월세 가구의 소득 분포는 저소득 월세 가구의 소득 둔화와 고소득 월세 가구의 출현으로 양극화가 진행되고 있다. 이에 본 연구는 보증부 월세시장을 통해 월세시장의 구조적 변화와 소득-임대료 간 부정합 현상을 정량화하는 지표로 월세 가구의 임대료와 소득을 동시에 비교하여 그 추이를 측정하였다. 11개년도(2006~2021년) 주거실태조사 마이크로데이터를 이용하여 2006년(기준연도) 월세 임대료(전월세 전환율 반영)와 월세 가구 소득을 각각4분위 분포로 구획한 후 10~15년 후(분석연도) 나타난 변화를 전국과 16개 광역시·도(세종시 제외) 공간 단위에서 분석하였다. 그 결과, 전국적인 월세 주택 공급에서 최고가 4분위(25% → 18%)와 3분위(25% → 20%)의 축소로 중·상위 월세 주택 공급난을 보인 반면 공공임대주택 공급으로 2분위(25% → 28%)와 최저가 1분위(25%→ 35%)는 확대되었다. 월세 가구의 수요 측면에서 최고소득 4분위(25% → 21%)의 축소와 달리 최저소득 1분위(25% → 31%)는 확대되었다. 16개 광역시·도를 비교해보면, 월세 임대료와 월세 가구소득의 변화 방향과 강도에 있어서 지역 간 상당한 격차가 확인되었다. 특히, 서울의 월세 주택 시장은 공급 양극화로 서울 월세 가구의 소득 분포와 불균형을 이루었다. 아파트 월세시장의 구조적 변화 양상은 비아파트 월세시장과 차별화되었다. 본 연구의 결과는 향후 지역별 월세 주택 시장에서 보증부 월세 가구의 소득 분위별로 부담 가능한 임차 주택 재고를 확보하고 지역별 소득과 임대료 분포 간의 균형을 유지할 수 있는 주거안정 방안을 마련하는데 기초자료로 활용될 수 있을 것이다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.23-23
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• 2009

GaN-based nitride semiconductors have attracted considerable attention in high-brightness light-emitting-diodes (LEDs) and laser diodes (LDs) covering from green to ultraviolet spectral range. LED and LD heterostructures are usually grown on (0001)-$Al_2O_3$. The large lattice mismatch between $Al_2O_3$ substrates and the GaN layers leads to a high density of defects(dislocations and stacking faults). Moreover, Ga and N atoms are arranged along the polar [0001] crystallographic direction, which leads to spontaneous polarization. In addition, in the InGaN/GaN MQWs heterostructures, stress applied along the same axis can also give rise to piezoelectric polarization. The total polarization, which is the sum of spontaneous and piezoelectric polarizations, is aligned along the [0001] direction of the wurtzite heterostructures. The change in the total polarization across the heterolayers results in high interface charge densities and spatial separation of the electron and hole wave functions, redshifting the photoluminescence peak and decreasing the peak intensity. The effect of polarization charges in the GaN-based heterostructures can be eliminated by growing along the non-polar [$11\bar{2}0$] (a-axis) or [$1\bar{1}00$] (m-axis) orientation instead of thecommonly used polar [0001] (c-axis). For non-polar GaN growth on non-polar substrates, the GaN films have high density of planar defects (basal stacking fault BSFs, prismatic stacking fault PSFs), because the SFs are formed on the basal plane (c-plane) due to their low formation energy. A significant reduction in defect density was recently achieved by applying blocking layer such as SiN, AlN, and AlGaN in non-polar GaN. In this work, we were performed systematic studies of the defects in the nonpolar GaN by conventional and high-resolution transmission electron microscopy.

• 대한지리학회지
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• 제49권3호
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• pp.390-404
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• 2014

본 연구는 수도권을 대상으로 종사자수와 취업자수를 지표로 직장과 주거지의 일치현상을 고찰하고 직주비와 통근통행간의 관계를 탐색한 것이다. 수도권에서는 2005~2010년 사이에 도시의 중심지기능을 수행해 온 도심지역에서 종사자수가 감소하고 인구증가 현상이 둔화되었고, 경기도가 차지하는 비중이 증가하면서 고용과 인구의 교외화현상이 진행되었다. 수도권에서는 종사자수에 비해 취업자수의 증가현상이 두드러지면서 취업자수 초과현상이 심화되었고, 이는 직주비를 감소시키는 요인으로 작용하였다. 특히 경기도에서의 직주불균형이 심화되었다. 사무직, 판매직, 전문직 등에서는 직주불균형이 개선된 지역이 많았지만, 단순노무직과 서비스직에서는 직주불균형이 심화된 지역이 많았다. 직종별로는 업무중심지일수록 더 많은 수의 직종에서 직주불균형이 개선되었다. 직주비가 높은 지역일수록 통근통행의 자족도가 낮게 형성되었으며, 다른 지역에서 유입되는 역외유입통행이 차지하는 비중이 높았다. 종사자수가 취업자수에 비해 월등하게 많았던 주요 고용중심지에서는 직주비와 역외유입통행률이 모두 감소하는 경향을 보였다.

• Investigative Magnetic Resonance Imaging
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• 제9권1호
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• pp.2-8
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• 2005

목적 : 뇌종양 및 확산텐서 영상으로 얻어진 그 주변 신경 다발을 동시에 가시화하는 소프트웨어를 구현하고 그것을 통해 뇌종양이 그 주변 신경다발에 미치는 영향에 대한 조사에의 적용 가능성을 시험해 보고자하였다. 대상 및 방법 : IDL을 기반으로 뇌종양과 그 주변 신경다발의 통합적 가시화를 구현하였다. 뇌종양을 가진 한 환자에 대한 T1 강조영상 및 확산텐서 영상을 포함하는 자기공명영상이 3.0T자기공명장치에서 획득되었다. 우리는 해부학적 정보를 위해 두개골을 제거한 뇌 영상과 구획화된 뇌종양을 위한 대조강화 T1 강조 영상을 이용하여 서피스 및 볼륨렌더링을 사용하였다. 대뇌 백질 신경 다발추적을 위해 사용되는 확산텐서영상을 위해서는 25개 방향의 확산경사 자계를 이용하는 SE-EPI방법을 사용하였다. 신경 다발추적 방법으로는 streamline과 tensorline 방법을 사용하였다. T1 강조 영상 및 확산텐서 영상의 공간적 불일치를 보정하기 위해 SPM을 이용한 정합을 수행하였다. 우리의 소프트웨어는 PC 윈도우 환경에서 작동할 수 있도록 구현되었다. 결과 : 한 명의 뇌종양 환자에 대하여 튜브 모양의 신경다발, 대뇌 백질 서피스 렌더링 , 뇌종양의 볼륨/서피스렌더링의 통합적 가시화를 성공적으로 구현하였다. 결론 : 우리의 결과는 뇌종양 및 그 주변 신경다발의 통합적 가시화의 실현 가능성을 보여주었다. 더불어 우리의 구현된 통합적 가시화는 뇌종양 부위 및 그 주변 부의의 대뇌 백질 확산 비등방성의 정량적인 분석에 사용될 수 있을 것으로 기대된다.

• Ocean and Polar Research
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• 제29권4호
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• pp.283-295
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• 2007

We investigated the longitudinal variations in zooplankton abundances and their related physicochemical properties at nine stations located between $136^{\circ}W$ and $128^{\circ}W$ at $10.5^{\circ}N$ in the northeastern Pacific in summer 2004. Temperature, salinity, inorganic nutrients, chlorophyll-a (hereafter chl-a) and zooplankton ($>200\;{\mu}m$) were sampled within the depth from the surface to 200 m depth at $1^{\circ}$ longitude intervals. Zooplankton($>200\;{\mu}m$) samples were vertically collected at two depth intervals from surface to 200 m, consisting of surface mixed and lower layers (thermocline$\sim$200 m). Longitudinal distributional pattern of hydrological parameters (especially salinity) was physically influenced by the intensity of westward geostrophic current passage relating to the NEC (North Equatorial Current). Data from the longitudinal survey showed clear zonal distributions in the hydrological parameters(temperature, salinity and nutrients). However, spatial patterns of the chl-a concentrations and zooplankton abundances were mostly independent of the zonal distributions of hydrological parameters. The two peaks of zooplankton abundance in the surface mixed layer were characterized by different controlling factors such as bottom-up control from nutrients to zooplankton ($129^{\circ}W$) and accumulation by increment of friction force and taxonomic interrelationship ($133^{\circ}$ and $134^{\circ}W$). Divergence-related upwelling caused introduction of nutrients into surface waters leading to the increment of chl-a concentration and zooplankton abundances ($129^{\circ}W$). Increased friction force in relation to reduced flow rates of geostrophic currents caused accumulation of zooplankton drifting from eastern stations of study area($133^{\circ}$ and $134^{\circ}W$). Besides, high correlation between immature copepods and carnivorous groups such as chaetognaths and cyclopoids also possibly contributed to the enhanced total abundance of zooplankton in the surface mixed layer (p<0.05). Zooplankton community was divided into three groups (A, B, C) which consecutively included the eastern peak of zooplankton($129^{\circ}W$), the western peak($133^{\circ}$ and $134^{\circ}W$) and high nutrient but low chl-a concentration and zooplankton abundance ($136^{\circ}W$). Moreover, Group B corresponded to the westward movement of low saline waters(<33.6 psu) from 128 to $132^{\circ}W$. In summary, longitudinal distributions of zooplankton community was characterized by three different controlling factors: bottom-up control ($129^{\circ}W$), accumulation by increased friction force and relationships among zooplankton groups ($133^{\circ}$ and $134^{\circ}W$), and mismatch between hydrological parameters and zooplankton in the high nutrient low chlorophyll area ($136^{\circ}W$) during the study period.

• 한국지역지리학회지
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• 제13권2호
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• pp.119-128
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• 2007

입도경향분석은 퇴적물 입도경향으로부터 퇴적물의 순이동방향을 도출하는 방법론이다. 입도경향으로부터 도출된 퇴적물의 순이동방향이 낙동강 하류의 삼각주연안 사주점의 지형변화 패턴과 잘 부합한다면 입도경향분석은 삼각주연안 사주섬의 지형변화를 연구하는 과정에서 효과적인 접근법이 될 수 있을 것이다. 이 연구는 Gao and Collins(1992)의 '퇴적물 이동벡터'법에 따라 도출한 퇴적물 순이동방향이 낙동강의 삼각주연안 사주섬의 지형변화를 이해하는 데 적절히 활용될 수 있는지를 검토한 것이다. 연구결과 퇴적물 이동벡터로부터 얻어진 퇴적물 순이동방향은 대체로 항공사진을 통해 추출한 지형변화 패턴를 반영하고 있음을 확인하였으나 지형변화가 급속히 일어나는 지역에서는 그렇지 않았다. 이는 입도경향분석을 통해 얻은 퇴적물 순이동방향이 대표하는 프로세스의 시간적 규모와 지형변화 분석자료의 시간적 규모, 지형변화율 등의 요소의 부합, 불부합 여부 등이 관련되어 있다고 판단된다. 입도경향분석을 낙동강 삼각주연안 사주섬에 적용하고자 할 경우 설명가능한 시간적 규모를 고려한 신중한 접근과 해석이 필요하다고 사료된다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.99-99
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• 2013

In this talk, I will present two research works in progress, which are: i) mapping of piezoelectric polarization and associated charge density distribution in the heteroepitaxial InGaN/GaN multi-quantum well (MQW) structure of a light emitting diode (LED) by using inline electron holography and ii) in-situ observation of the polarization switching process of an ferroelectric Pb(Zr1-x,Tix)O3 (PZT) thin film capacitor under an applied electric field in transmission electron microscope (TEM). In the first part, I will show that strain as well as total charge density distributions can be mapped quantitatively across all the functional layers constituting a LED, including n-type GaN, InGaN/GaN MQWs, and p-type GaN with sub-nm spatial resolution (~0.8 nm) by using inline electron holography. The experimentally obtained strain maps were verified by comparison with finite element method simulations and confirmed that not only InGaN QWs (2.5 nm in thickness) but also GaN QBs (10 nm in thickness) in the MQW structure are strained complementary to accommodate the lattice misfit strain. Because of this complementary strain of GaN QBs, the strain gradient and also (piezoelectric) polarization gradient across the MQW changes more steeply than expected, resulting in more polarization charge density at the MQW interfaces than the typically expected value from the spontaneous polarization mismatch alone. By quantitative and comparative analysis of the total charge density map with the polarization charge map, we can clarify what extent of the polarization charges are compensated by the electrons supplied from the n-doped GaN QBs. Comparison with the simulated energy band diagrams with various screening parameters show that only 60% of the net polarization charges are compensated by the electrons from the GaN QBs, which results in the internal field of ~2.0 MV cm-1 across each pair of GaN/InGaN of the MQW structure. In the second part of my talk, I will present in-situ observations of the polarization switching process of a planar Ni/PZT/SrRuO3 capacitor using TEM. We observed the preferential, but asymmetric, nucleation and forward growth of switched c-domains at the PZT/electrode interfaces arising from the built-in electric field beneath each interface. The subsequent sideways growth was inhibited by the depolarization field due to the imperfect charge compensation at the counter electrode and preexisting a-domain walls, leading to asymmetric switching. It was found that the preexisting a-domains split into fine a- and c-domains constituting a $90^{\circ}$ stripe domain pattern during the $180^{\circ}$ polarization switching process, revealing that these domains also actively participated in the out-of-plane polarization switching. The real-time observations uncovered the origin of the switching asymmetry and further clarified the importance of charged domain walls and the interfaces with electrodes in the ferroelectric switching processes.

• 대한의용생체공학회:의공학회지
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• 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.