• 한국광학회:학술대회논문집
• /
• 한국광학회 2003년도 하계학술발표회
• /
• pp.60-61
• /
• 2003

A new approach to reduce the computation time of genetic algorithm (GA) for making binary phase holograms is described. Synthesized holograms having diffraction efficiency of 75.8% and uniformity of 5.8% are proven in computer simulation and experimentally demonstrated. Recently, computer-generated holograms (CGHs) having high diffraction efficiency and flexibility of design have been widely developed in many applications such as optical information processing, optical computing, optical interconnection, etc. Among proposed optimization methods, GA has become popular due to its capability of reaching nearly global. However, there exits a drawback to consider when we use the genetic algorithm. It is the large amount of computation time to construct desired holograms. One of the major reasons that the GA' s operation may be time intensive results from the expense of computing the cost function that must Fourier transform the parameters encoded on the hologram into the fitness value. In trying to remedy this drawback, Artificial Neural Network (ANN) has been put forward, allowing CGHs to be created easily and quickly (1), but the quality of reconstructed images is not high enough to use in applications of high preciseness. For that, we are in attempt to find a new approach of combiningthe good properties and performance of both the GA and ANN to make CGHs of high diffraction efficiency in a short time. The optimization of CGH using the genetic algorithm is merely a process of iteration, including selection, crossover, and mutation operators [2]. It is worth noting that the evaluation of the cost function with the aim of selecting better holograms plays an important role in the implementation of the GA. However, this evaluation process wastes much time for Fourier transforming the encoded parameters on the hologram into the value to be solved. Depending on the speed of computer, this process can even last up to ten minutes. It will be more effective if instead of merely generating random holograms in the initial process, a set of approximately desired holograms is employed. By doing so, the initial population will contain less trial holograms equivalent to the reduction of the computation time of GA's. Accordingly, a hybrid algorithm that utilizes a trained neural network to initiate the GA's procedure is proposed. Consequently, the initial population contains less random holograms and is compensated by approximately desired holograms. Figure 1 is the flowchart of the hybrid algorithm in comparison with the classical GA. The procedure of synthesizing a hologram on computer is divided into two steps. First the simulation of holograms based on ANN method [1] to acquire approximately desired holograms is carried. With a teaching data set of 9 characters obtained from the classical GA, the number of layer is 3, the number of hidden node is 100, learning rate is 0.3, and momentum is 0.5, the artificial neural network trained enables us to attain the approximately desired holograms, which are fairly good agreement with what we suggested in the theory. The second step, effect of several parameters on the operation of the hybrid algorithm is investigated. In principle, the operation of the hybrid algorithm and GA are the same except the modification of the initial step. Hence, the verified results in Ref [2] of the parameters such as the probability of crossover and mutation, the tournament size, and the crossover block size are remained unchanged, beside of the reduced population size. The reconstructed image of 76.4% diffraction efficiency and 5.4% uniformity is achieved when the population size is 30, the iteration number is 2000, the probability of crossover is 0.75, and the probability of mutation is 0.001. A comparison between the hybrid algorithm and GA in term of diffraction efficiency and computation time is also evaluated as shown in Fig. 2. With a 66.7% reduction in computation time and a 2% increase in diffraction efficiency compared to the GA method, the hybrid algorithm demonstrates its efficient performance. In the optical experiment, the phase holograms were displayed on a programmable phase modulator (model XGA). Figures 3 are pictures of diffracted patterns of the letter "0" from the holograms generated using the hybrid algorithm. Diffraction efficiency of 75.8% and uniformity of 5.8% are measured. We see that the simulation and experiment results are fairly good agreement with each other. In this paper, Genetic Algorithm and Neural Network have been successfully combined in designing CGHs. This method gives a significant reduction in computation time compared to the GA method while still allowing holograms of high diffraction efficiency and uniformity to be achieved. This work was supported by No.mOl-2001-000-00324-0 (2002)) from the Korea Science & Engineering Foundation.

• 대한원격탐사학회지
• /
• 제37권5_2호
• /
• pp.1295-1305
• /
• 2021

연안 및 대양의 효과적인 모니터링을 위해 여러 연구 분야에서 고품질의 위성 기반 해색 산출물들이 요구 있으며 이를 위해서는 정확한 대기 효과의 보정이 필수적이다. 현재 Geostationary Ocean ColorImage (GOCI)-II 지상시스템에서는 수증기 및 오존 등에 의한 가스 흡광 보정을 수행하기 위해 European Centre for Medium-Range Weather Forecasts (ECMWF) 또는 National Centers for Environmental Prediction (NCEP) 기상장 자료를 사용하고 있다. 이 과정에서 기상장 자료의 낮은 시공간해상도로 인해 오차가 발생할 수 있다. 따라서 본 연구에서는 복사 전달 모델 모의를 통해 개발된 GOCI-II의 수증기 흡광 보정 모델 및 GeoKompsat (GK)-2A/Advanced Meteorological Imager (AMI)의 가강수량 자료를 이용하여 수증기 흡광 효과를 보정하고 이에 따른 영향력을 분석하였다. 개발된 수증기 흡광 보정 모델 적용 유무에 따른 오차는 수증기의 영향이 적은 620 nm와 680 nm의 대기 상한 반사도에서 최대 1.3%와 0.27%로 적은 오차를 보였다. 그러나 수증기 흡광의 경향이 큰 709 nm 채널의 경우 태양 천정각 및 가강수량에 따라 6~15%의 큰 오차를 나타냈다. 레일리 보정 반사도에서는 대기 상한 반사도에서 발생한 오차가 크게 증폭되어 태양 천정각에 따라 GOCI-II의 각 밴드(620~865 nm) 별로 1.46~4.98, 7.53~19.53, 0.25~0.64, 14.74~40.5, 8.2~18.56, 5.7~11.9%의 큰 오차를 보이고 있다. 이는 수증기 흡광 보정이 해색 산출물의 정확도와 안정성에 큰 영향을 미칠 수 있다는 것을 의미하며, 향후 시공간 해상도가 높은 GK-2A/AMI와의 융합을 통해 GOCI-II 해색 산출물의 정확도 향상이 가능함을 시사한다.

• 한국해안·해양공학회논문집
• /
• 제31권1호
• /
• pp.28-39
• /
• 2019

해빈 안정화를 위한 구조물 설계 시 주 표사이송 모드와 모드별 년 표사 이송량에 관한 정보는 상당한 공학적 가치를 지닌다. 이러한 시각에서 본고에서는 현재 상당한 침식이 진행되고 있는 맹방해변의 년 표사 이송량을 산출하였다. 횡단표사의 경우 Bagnold(1963)의 에너지 모형을 확장한 Bailard(1981)의 모형을 활용하였으며, 연안 표사량은 각 해안에서 가용한 파랑에너지 유입률에 의해 결과 되는 것으로 해석하였다. Bailard(1981)의 횡단표사모형 적용에 필요한 유속 적률은 먼저 맹방해변에서 관측된 파랑자료로부터 출현 가능한 총 71개의 파랑주기 복합사상을 선정하고, 선정된 복합사상을 대상으로 수행된 맹방해변에서의 비선형 천수과정 수치모의 결과로부터 산출하였다. 이 과정에서 파랑모형으로는 주파수 영역 Boussinesq Eq.(Frelich and Guza, 1984)을 활용하였으며, 모의결과 Bailard(1981)의 연구와는 달리 유속 적률과 Irribaren NO. 간에 존재하는 뚜렷한 상관관계를 확인할 수 있었다. 산출 결과 맹방해변 평균 방위 ${\beta}=41.6^{\circ}$의 경우 북서진하는 연안표사가 우월하며 그 양은 년 $125,000m^3/m$에 달하였다. 북서진하는 연안표사와 남동진하는 연안표사가 균형을 이루는 null point는 ${\beta}=47^{\circ}$에 위치하며, 횡단표사의 경우 4월부터 10월 중순까지는 연안방향으로의 퇴적이 점진적으로 진행되나 10월 말과 삼월에 단발적으로 발생하는 고파랑에 의해 침식되는 것으로 판단된다. 또한 맹방해변의 연안표사 장미도(littoral drift rose)를 산출하였으며, 그 결과 맹방해변의 방위가 일시적으로 null point의 방위보다 큰 경우 남동진하는 연안표사가 우월하며, 방위가 일시적으로 null point의 방위보다 작은 경우 북서진하는 연안표사가 우월한 경향을 확인하였으며, 이는 맹방해변은 일시적으로 침식되더라도 스스로 복원할 수 있는 능력을 지닌 안정적인 해변임을 의미한다.

• 대한원격탐사학회지
• /
• 제38권5_1호
• /
• pp.497-510
• /
• 2022

농업용 저수지는 수자원이 계절적으로 편중된 한반도에서 갈수기 용수 공급을 위한 필수적인 구조물이다. 효율적인 물 관리를 위해서는 중소규모 저수지에 대한 체계적이고 효과적인 모니터링이 필요하며, 합성개구 레이더(Synthetic Aperture Radar, SAR) 영상은 전천후 관측이 가능하다는 특징과 함께 연속적인 저수지 모니터링을 위한 도구가 된다. 본 연구에서는 10 m급 해상도를 갖는 Sentinel-1 SAR 영상과 1 m급 해상도의 Capella X-SAR 영상을 활용하여 울산광역시 차리, 갈전, 뒷골 저수지의 수체를 탐지하였으며, 이를 통해 국내 중소규모 저수지 모니터링에의 활용성을 평가하고자 하였다. Z fuzzy function 기반 임계값 산정을 통한 영상분할기법과 객체 탐지 기반 분할기법인 Chan-vese (CV) 기법을 통해 수체 영역을 산정하였으며, UAV 영상과의 비교를 통해 성능을 정량적으로 평가하였다. 임계값 기반 탐지 정확도는 Sentinel-1의 경우 약 0.87, 0.89, 0.77 (차리, 갈전, 뒷골), Capella의 경우 약 0.78, 0.72, 0.81로 나타났으며, CV 기법 적용 시 모든 저수지에서 정확도가 향상되는 것을 확인하였다(Sentinel-1: 0.94, 0.89, 0.84, Capella: 0.92, 0.89, 0.93). Capella는 모든 저수지/분할기법에 대해 수체와 비수체의 경계를 비교적 뚜렷하게 모의하였으나, 고해상도로 인한 speckle noise가 충분히 평활화되지 않아 오탐지 및 미탐지가 다소 발생하였다. 오탐지의 제거를 위해 광학 센서 기반 보조자료를 활용하여 마스킹한 결과, 정확도가 최대 13% 향상되는 것을 확인할 수 있었다. 본 연구 결과를 바탕으로 SAR 위성 기반 더욱 정확한 저수지 탐지가 이루어진다면 소규모 저수지를 포함, 종합적인 가용수량에 대한 연속적인 모니터링이 가능할 것이며, 효과적인 수자원 관리에 기여할 수 있을 것으로 기대된다.

• 한국항해항만학회지
• /
• 제46권1호
• /
• pp.1-10
• /
• 2022

본 연구는 제4차 산업혁명 기술에 의해 선박의 자동화와 지능화가 진전되면서 자율운항선박이 도입되게 됨에 따라 해기사 인력수요축소와 직능 전환 등의 문제가 대두되는 상황에서 해기사의 직무변화와 이에 따른 요구 역량을 분석하고 이를 배양하기 위한 인력양성 방향을 제시하였다. 선행연구 검토와 전문가 집단의 브레인스토밍과 AHP 설문조사를 통해 자율운항선박의 해기사 직무와 역량 요인을 도출하고 그 중요도를 평가하였다. 해기사 승선 자율운항선박의 해기사 직무 중에서 안전 운항과 비상시 대응 그리고 화물의 안전운송 관련 직무요인이 중요한 것으로 나타났으며, 자율운항시스템의 제어 및 운용 역량의 중요성이 매우 높으며 이를 뒷받침하기 위한 육·해상 커뮤니케이션과 AI 및 Big Data 분석 역량이 필요한 것으로 나타났다. 완전자율운항선박의 해기사 직무는 예상하지 못한 비상상황에 대비하여 선박을 안전하게 원격운항시키는 비상상황대처, 원격운항제어, 선박정비·관리 직무 순으로 중요도가 높으며, 해기사 역량에서는 자율운항시스템 제어와 운용 그리고 이를 수행하기 위한 Big Data 와 AI 활용 역량들의 중요도가 매우 높은 것으로 분석되었다, 이러한 요인들의 직무역량 함양을 위한 해기인력 양성 방향과 규모는 기술의 진보에 따라 크게 달라질 수 있는 점을 고려하여 자율운항선박 도입단계별로 필요한 해기사 교육 프로그램과 직무교육 내용 그리고 핵심역량 함양을 위한 교육인프라 구축 방안을 제시하였다. 이 연구는 자율운항선박의 해기사 직무 및 역량 요인을 실무적 관점에서 체계적으로 도출하였으며, 관련 전문가별 인식도를 분석함으로써 자율운항선박 도입에 대한 전문가 차원의 대응 방안을 진단하였다는데 연구의 의의가 있다.

• 벤처창업연구
• /
• 제18권1호
• /
• pp.253-270
• /
• 2023

스타트업에게 전문보육과 투자를 동시에 제공함으로써 스타트업의 생존율을 크게 개선하여 주목을 받고 있는 액셀러레이터의 투자결정요인에 대한 연구는 점점 확대되고 있다. 그러나 선행 연구들은 초기 단계로 투자결정요인 개발 시 이론적 기반을 갖추지 못한 상황으로 유사 투자자인 엔젤투자자나 벤처캐피탈의 투자결정요인을 사용하고 있으며 실증연구를 통해 중요도와 우선순위를 분석하는 단계에 머물고있다. 따라서 본 연구는 선행연구에서 비즈니스 모델 혁신 프레임워크를 기반으로 개발된 액셀러레이터 투자결정요인을 사용하여 투자결정요인의 변별력과 유효성을 국내 최초로 실증 검증하였다. 이를 위해 먼저 액셀러레이터의 스타트업 투자 성공과 실패의 판단 기준을 스케일업 이론을 기반으로 설정한 후 국내 14개 액셀러레이터의 22명의 투자전문가를 대상으로 설문조사를 시행한 결과 액셀러레이터의 스타트업 투자 후 스케일업에 성공한 스타트업 52개사, 스케일업에 실패한 스타트업 45개사 등의 총 97개 스타트업의 유효한 자료를 확보하였으며 이 두 그룹 간의 액셀러레이터 투자결정요인별 평균 차이를 검증하기 위해 독립표본 t-검정을 실시하였다 분석 결과 총 21개의 투자결정요인 중 9개(43%) 요인에서 평균 차이를 확인함으로써 비즈니스 모델 혁신 프레임워크 기반의 액셀러레이터의 투자결정요인이 실무적으로 액셀러레이터가 성공 가능한 스타트업을 발굴하고 투자의사결정을 하는데 상당한 변별력을 보유한 것으로 확인하였다. 또한 스타트업의 업종별 혁신의 특성을 고려하여 연구 대상 스타트업 표본을 제조업 분야 스타트업과 서비스업 분야 스타트업으로 구분하여 분석한 결과 제조업 분야 스타트업에서는 비즈니스 모델, 전략, 동적역량 요인에서 평균 차이가 발생한 반면 서비스업 분야 스타트업은 동적역량 요인에서만 평균 차이가 발생하였다. 본 연구는 비즈니스 모델 혁신 프레임워크를 기반으로 도출한 액셀러레이터 투자결정요인의 실무적 유효성을 실증연구를 통해 국내 최초로 검증하였다는 점에서 학문적 시사점이 크며, 액셀러레이터에게 투자의사결정을 위한 이론적 근거와 세부 투자결정요인에 대한 구체적인 정보를 제공함으로써 효과적인 투자를 할 수 있게 한다는 점에서 실무적 가치가 높다.

• 벤처창업연구
• /
• 제17권5호
• /
• pp.1-16
• /
• 2022

창업은 국가경쟁력을 높이고 고용을 창출하는 국가 핵심 전략임에도 불구하고 스타트업의 생존율은 크게 개선되고 있지 않다. 이는 기존 창업지원기관과 투자자의 고유한 한계성으로 창업의 초기단계인 스타트업에게 적시에 적절한 지원을 제공하지 못하는 것이 중요한 원인이다. 비교적 최근에 등장한 액셀러레이터는 스타트업에게 전문보육과 투자를 동시에 제공함으로 스타트업의 생존율을 크게 개선하여 주목받고 있다. 그러나 액셀러레이터의 생존과 성공에 영향을 미치는 투자결정요인에 대한 연구는 소수의 실증연구만 있을 뿐이며 이론적 근거가 부족한 실정이다. 본 연구는 선행연구를 통해 이론적 기반을 제시한 비즈니스 모델 혁신 관점의 액셀러레이터 투자결정요인을 21개로 세분화하여 국내 액셀러레이터 투자전문가를 대상으로 AHP(Analytic Hierarchy Process, 계층분석과정) 분석 기법을 사용하여 요인별 중요도를 분석하였다. 분석 결과 액셀러레이터 투자결정요인 중요도의 상위요인은 '인적자원', '고객·시장', '지적자원', '창업가의 기회실현능력' 순으로 나타났다. 이는 액셀러레이터가 스타트업 투자의사결정시 솔루션 구현을 위한 스타트업의 핵심역량을 가장 중요한 요인으로 생각하고 있음을 알 수 있다. 또한 액셀러레이터는 스타트업의 핵심 경쟁력에 기반 한 명확한 가치제안과 차별화된 시장 포지션을 창출할 수 있도록 전략적이고, 핵심가치의 전달 방식은 시장 지향적인 비즈니스 모델을 선호하며, 급변하는 시장 속에서 한정된 자원으로 비즈니스 모델을 실현하기 위해서는 창업가의 혁신역량을 중요한 요인으로 인식하고 있음을 확인할 수 있었다. 본 연구는 액셀러레이터 투자 대상이 되는 스타트업의 본질과 목표, 주요 활동을 잘 반영하고 있는 비즈니스 모델 혁신 이론에 근거해 도출한 액셀러레이터의 투자결정요인에 대한 후속 연구로서 액셀러레이터의 투자결정요인의 중요도를 분석하였다는 점에서 학문적 의의가 있다. 또한 액셀러레이터에게 투자의사결정을 위한 이론적 근거와 세부 투자결정요인에 대한 구체적인 정보를 제공함으로써 효과적인 투자를 할 수 있게 하며 투자유치를 희망하는 스타트업이 투자유치를 위해 무엇을 준비해야 하는지 안내함으로써 국내 스타트업 투자생태계 활성화에 기여함으로 실무적 가치가 있다.

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

• 마케팅과학연구
• /
• 제20권1호
• /
• pp.35-48
• /
• 2010

今天, 受到成熟零售市场挑战的时装市场需要新的 "品牌发展" 典范来提高他们的竞争优势. 时装市场的一个重要议题是为满足消费者由于生活方式的变化而产生的特别需求所进行的生活方式品牌扩张. 时装品牌扩张到生活方式产品类别, Y世代和婴儿潮可以说是新兴的 "前景"(婴儿潮的消费者正在改变他们的生活方式. Y世代正经历着他们生命阶段的变化). 他们有购买新产品的需求. 因此, 服装公司为品牌扩张注重消费群从而在新的产品类别中建立和管理他们的品牌资产是乐观的. 本文的研究目的是(a)评估母品牌和子品牌的品牌资产. (b)鉴定消费者对品牌扩张的感知营销因素. (c)评估两个选择的群体(Y世代和婴儿潮)的营销因素和扩张到生活方式的产品类别(包括家居时尚产品)品牌的品牌资产之间因果关系的结构方程模型. 关于理论框架, 本文关注传统的营销4P组合来鉴定哪个营销因素在品牌扩张资产方面更重要. 比较营销可以建立 "品牌扩张资产", 从而成功的进入新类别. 借鉴相关的文献, 通过关注选择的消费者(Y世代, 婴儿潮), 本研究发展的研究假设结合了品牌资产因子和营销因素. 在品牌扩张至生活方式产品的背景下, 品牌资产的构念包括品牌认知/联合, 品牌感知(例如感知质量, 情感价值)和从CBBE因子(Keller, 2001)中而来的品牌共鸣. 据推测, 通过品牌扩张至生活方式产品, 市场营销要素在品牌认知/联合, 品牌感知方面创建品牌扩张资产, 进而影响品牌的共鸣. 为了收集数据, 样本由韩国Y世代的女性消费者和在婴儿潮中出生的消费者. 这些在婴儿潮中出生的消费者由于生活周期的改变而对生活方式产品有较高的需求. 在韩国Y世代(n=326)和婴儿潮(n=325)的女性消费者中共有651份有用的问卷被使用. 我们用LISREL8.8测试了使用相关矩阵的结构和测量模型. 结果显示品牌扩张的感知营销因素包括三个因子: 价格/店铺形象, 产品和广告. 在Y世代的模型中, 价格/店铺形象对品牌资产因素有积极的影响(例如品牌认知/联合, 感知质量). 同时, 在品牌扩张中产品对情感价值有积极的影响. 品牌认知/联合有可能提高感知质量和情感价值, 从而对扩张至生活方式产积极的品牌产生品牌共鸣. 在婴儿潮消费者模型中, 价格/店铺形象对感知质量有积极的影响, 感知质量可以创造品牌扩张的品牌共鸣. 产品对质量感知和情感价值有正的影响, 这些都会消费者产生对扩张至生活方式产品的品牌的品牌共鸣. 但是, 在这两个群体中广告和品牌资产都是负相关. 本研究为时装营销者提供了发展成功的品牌扩张战略以及可持续的竞争优势的见解. 本研究补充和扩展了先前的有关通过营销努力的因素促使品牌扩张成功的研究. 研究结果支持为进入新的产品类别, 时装品牌扩张(Aaker and Keller, 1990; Tauber, 1998; Shine et al., 2007; Pitta and Katsanis, 1995)和营销行动的增效作用. 因此, 我们推荐营销者同时针对Y世代和婴儿潮一代通过标准化的营销推广进入新产品类别(例如家具)可以降低营销成本. 时装营销者可以(a)提供高价的产品线. (b)在韩国通过零售渠道(例如专门百货商店)强调高档特征的商店形象定位. (c)结合服装与生活方式产品包括新颖的款式和设计师的限量版. 对品牌资产,成功品牌延伸的关键是消费者的品牌认知度和品牌联合,确保新产品类别的品牌特征. 对于营销者来说, 在进入新产品类别的时候知道什么有助于更具体的联合是必要的. 对时装品牌而言, 品牌扩张的第二个关键是进入 "奢侈" 生活方式新产品类别的途径. 更高的价格或店铺形象都对质量感知有影响. 而质量感知可以引起品牌共鸣. 更重要的是, 本研究提高了对品牌扩张的理论理解并对营销者提出了在制定针对Y世代和婴儿潮一代消费者的行销项目时的方向.

• 항공우주정책ㆍ법학회지
• /
• 제29권1호
• /
• pp.127-160
• /
• 2014

유엔 우주평화적이용위원회는 우주의 평화적 이용을 위한 국제 협력의 촉진, 유엔의 우주 관련 프로그램의 수립, 우주 연구의 독려와 관련 정보의 보급, 그리고 우주의 이용과 탐사로부터 발생하는 법적 문제를 연구하기 위하여 1959년 유엔 총회의 상설위원회로 설립되었다. 우주평화적이용위원회의 회원국은 설립 당시 24개국에서 2014년 현재 76개국으로 확대되었다. 우주활동에 고유한 법적 문제를 다루기 위하여 1962년 설립된 우주평화적이용위원회 법률소위원회는 30여 년간 5개 조약(1967 우주조약, 1968 구조 협정, 1972 책임협약, 1975 등록협약, 1979 달협정)과 5개 원칙 및 선언을 체결 또는 채택하였다. 우주평화적이용위원회의 이러한 노력으로, 관습국제법이 거의 전무하다시피 한 우주 분야에 새로운 국제법 체계를 성립되었다. 그러나 실제 문제에 대한 국제우주법의 적용을 비롯하여 지속적인 기술 발전에 따라 새로운 유형의 우주활동이 등장하자, 기존의 국제우주법에 대한 회의적 시각이 조금씩 표출되었다. 우주평화적이용위원회는, UNISPACE III를 계기로, 법률소위원회의 논의에 활기를 불어놓고 국제사회가 직면한 새로운 법적 이슈에 대응하기 위하여, 의제를 세 가지 유형으로 분류하였다: 정규 의제, 단일 의제, 복수년 의제. 정규 의제는 일단 채택이 되면 기한의 제한 없이 매년 토의하는 의제로서, 영공과 우주의 경계획정, 유엔 5개 우주 관련 조약의 현황과 적용, 우주의 평화적 탐사와 이용에 관한 국내입법 등이 있다. 단일 의제는 논의 기한이 1년이며 다음해 해당 의제를 계속 논의할 것인지의 여부는 당년에 결정된다. 2015년 단일 의제로 우주에서 핵동력원 사용 원칙의 검토와 개정 그리고 우주쓰레기 경감 조치 관련 법 메커니즘에 대한 정보 교류가 있다. 복수년 의제는 상세한 법적 분석이 필요한 의제의 경우 작업반을 설립하여 다년간 논의하는 의제로서, 우주의 평화적 탐사와 이용을 위한 국제협력 메커니즘과 비구속력 국제문서가 있다. 그리고 법률소위원회의 최근 논의는 핵동력원, 우주쓰레기, 국제 협력 등에 집중되어 있으며, 법률소위원회는 비구속력 문서, 즉 연성법을 통해 이러한 문제를 규제하려고 한다. 우리나라는 1994년 말레이시아 그리고 페루와 함께 2년간 순환제로 우주평화적이용위원회에 참여해 오다, 2001년 정식 회원국이 되었다. 그러나 차드, 시에라리온, 케냐, 레바논, 카메룬 등과 같이 오늘날 우주활동을 거의 수행하지 않는 국가들이 1960~70년대 우주평화적이용위원회에 가입하여 유엔 5개 우주 관련 조약과 유엔 총회 결의문의 작성에 참여한 것을 보면 우리나라의 우주평화적이용위원회의 가입은 매우 늦은 편이다. 한편, 법률소위원회는 조약 체결의 어려움과 규제의 시급성을 감안하여 유엔 총회 결의, 가이드라인 등 연성법의 형성에 중점을 두고 있다. 이와 관련하여, 우리나라는 국내의 우주 관련 과학기술, 정책, 법 등을 분석하여 연성법의 논의 과정에 적극 참여하여야 한다. 이러한 참여는 기존의 국제우주법 형성에 있어서 우리나라의 불참을 조금이나마 벌충할 수 있는 기회일 뿐만 아니라, 관습국제법의 중요한 요소인 관행에 우리나라의 관행을 끼워 넣을 수 있는 최선의 방안이기 때문이다.