• 대한의용생체공학회:학술대회논문집
• /
• 대한의용생체공학회 1998년도 추계학술대회
• /
• pp.157-158
• /
• 1998

The purpose of this study was to test the hypothesis that even very small change of the cue direction in the treatment of the early osteonecrosis could affect the outcomes of operation. For this, the changes in stress transfer within the necrotic area of the femoral head were investigated under various directions and placements of the core utilizing finite element method. The loading of 3188N, which represents after-heel-strike, was imposed in cubic cosine pattern. All nodes on the most distal surface of the model were constrained in all directions. All materials included were assumed to have linear-elastic behavior. The result says that the critical stress, which causes collapse of the femoral head, was reduced when the core was oriented toward the posterior side of the femoral head regardless of location of the necrotic area. The same result was obtained either fibular bone grafting or cementation was adopted. As a consequence, the biomechanical study suggests that the core should be directed toward the loading point where the resultant force is applied to get more desirable treatment of the osteonecrosis of the femoral head in the early stage.

• 대한원격탐사학회지
• /
• 제27권3호
• /
• pp.379-388
• /
• 2011

At present, GEOBIA (Geographic Object-based Image Analysis), heir of OBIA (Object-based Image Analysis), is regarded as an important methodology by object-oriented paradigm for remote sensing, dealing with geo-objects related to image segmentation and classification in the different view point of pixel-based processing. This also helps to directly link to GIS applications. Thus, GEOBIA software is on the booming. The main theme of this study is to look into the applicability of geo-spatial processing open source to GEOBIA. However, there is no few fully featured open source for GEOBIA which needs complicated schemes and algorithms, till It was carried out to implement a preliminary system for GEOBIA running an integrated and user-oriented environment. This work was performed by using various open sources such as OTB or PostgreSQL/PostGIS. Some points are different from the widely-used proprietary GEOBIA software. In this system, geo-objects are not file-based ones, but tightly linked with GIS layers in spatial database management system. The mean shift algorithm with parameters associated with spatial similarities or homogeneities is used for image segmentation. For classification process in this work, tree-based model of hierarchical network composing parent and child nodes is implemented by attribute join in the semi-automatic mode, unlike traditional image-based classification. Of course, this integrated GEOBIA system is on the progressing stage, and further works are necessary. It is expected that this approach helps to develop and to extend new applications such as urban mapping or change detection linked to GIS data sets using GEOBIA.

• 한국물환경학회지
• /
• 제33권6호
• /
• pp.696-714
• /
• 2017

Simple material budget models were developed to predict the spring season (March ~ May) water quality for a river-type reservoir Paldang, in the Republic of Korea. These models are available at mixed water bodies whose light intensity is negligible at the bottom. The calculated data from the models fit quite well with field data collected for 30 years, from 1988 to 2017. The apparent settling velocity of total phosphorus was estimated to be $110m\;d^{-1}$. The critical hydraulic load that determines the usability of phosphorus for algal production appeared to be about $2.0m\;d^{-1}$. When a hydraulic load was larger than the critical value, the concentrations of chlorophyll ${\alpha}$ ($Chl.{\alpha}$), chemical oxygen demand (COD), and 5-day biochemical oxygen demand BOD in the reservoir water became insensitive to internal algal reactions. The model analysis showed that the allochthonous COD continued to increase while the allochthonous BOD slightly decreased after 1999. The decrease of allochthonous BOD is due to the expansion of sewage and wastewater treatment plants in the watershed. The increase of allochthonous COD seems to result from the increase in anthropogenic non-point sources as well as the increase in the discharge of natural organic matters due to climate change. Organic matter of algal origin continued to increase until the mid-2000s, but recently it has decreased as the phosphorus concentration has decreased. The COD and BOD of algal origin increased from 35 % and 27 % during 1988 ~ 1994 to 43 % and 40 % during 2000 ~ 2010, respectively, and then decreased to 25 % and 28 % during 2011 ~ 2017.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2006년도 춘계학술대회논문집
• /
• pp.1334-1337
• /
• 2006

System identification is the field of modeling dynamic systems from experimental data. As a modeling technique, we can mention finite element method (FEM). In addition, we are able to measure modal data as the experimental data. The system can be generally categorized into a gray box and black box. In the gray box, we know mathematical model of a system, but we don't know structural parameters exactly, so we need to estimate structural parameters. In the black box, we don't know a system completely, so we need to identify system from nothing. To date, various system identification methods have been developed. Among them, we introduce system realization theory which uses Hankel matrix and Eigensystem Realization Algorithm (ERA) that enable us to identify modal parameters from noisy measurement data. Although we obtain noise-free data, however, we are likely to face difficulties in identifying a structure with hidden modes. Hidden modes can be occurred when the input or output position comes to a nodal point. If we change a system using a mode decoupling controller, the hidden modes can be revealed. Because we know the perturbation quantities in a closed loop system with the controller, we can realize an original system by subtracting perturbation quantities from the closed loop system. In this paper, we propose a novel method to identify a structure with hidden modes using the mode decoupling controller and the associated example is given for illustration.

• 한국건설관리학회논문집
• /
• 제10권2호
• /
• pp.46-54
• /
• 2009

우리나라는 1990년대에 건설발주 물량의 증가로 인한 건설기술자가 매우 부족한 실정이었다. 따라서 정부는 이러한 문제점을 해결하기 위하여 1995년에 인정기술자제도를 도입하게 되었다. 그러나, 2000년 이후 건설기술자의 부족 문제는 해결되었으나, 오히려 건설기술자의 공급과잉으로 인한 새로운 문제가 발생되었다. 따라서, 정부는 2007년도에 기존 인정기술자제도를 폐지하고, 건설기술자 제도는 산업기사, 기사, 기술사 등의 기술자격을 가진 자만 건설활동을 할 수 있는 제도로 변화되었다. 이러한 측면에서 본 연구는 정책변화에 따른 가장 적합한 건설기술자의 수요와 공급예측 모델을 개발하여 2008년부터 2017년까지 수요공급예측을 하는 것이 중요한 사항으로 대두되었다. 따라서, 본 연구는 GDP와 건설시장분석을 기반으로 건설기술자의 수요예측과 공급예측모델을 제안하고, 중장기 수급예측을 전망하였다. 이러한 연구결과는 정책수립자가 건설기술자의 수요와 공급의 수립시 기초자료로 활용할 수 있을 것이다.

• 대한치과보철학회지
• /
• 제37권4호
• /
• pp.506-515
• /
• 1999

Dental practice can produce and spread some infectious diseases from patients to dentist, dental assistant, and dental labors. One possible method for preventing these cross-contamination is to immerse dental impression in chemical disinfectants. So for many investigators studied on the dimensional changes of dental impressions and on the surface qualities of stone casts made from impression following immersion in disinfectants. This study was proposed to evaluate some popular impression disinfectant combination from the point of dimensional stability. Impression was taken from dental arch-shaped metal model. Irreversible hydrocolloid and 3 elastomers(polyvinyl siloxane, polysulfide, polyether) were immersed in 3 disinfectants (2% glutaraldehyde, 1% povidone-iodine, 0.5% sodium hypochlorite) for 10 minutes and measured both cross-arch and anterior-posterior distance under stereo microscope to evaluate dimensional change. The results obtained were as follows: 1. Dimensional changes of irreversible hydrocolloid impression was statistically different in cross-arch and anterior-posterior distance when immersed in 2% glutaraldehyde solution and in anterior-posterior distance when immersed in 0.5% sodium hypochlorite solution from control group (p<0.05). 2. Dimensional changes of polyvinyl siloxane and polysulfide impression were not statistically different from control group (p>0.05). 3. Dimensional changes of polyether impression was statistically different in cross-arch distance when immersed in 0.5% sodium hypochlorite solution and in anterior-posterior distance when immersed in 1% povidone-iodine solution from control group (p<0.05). 4. In all cases, dimensional changes were less than 0.1% from the original dimension and concluded clinically acceptable.

• 대한원격탐사학회지
• /
• 제36권4호
• /
• pp.587-607
• /
• 2020

Soil moisture is essential information for meteorological and hydrological analyses. To date, many efforts have been made to achieve the two goals for soil moisture data, i.e., the improvement of accuracy and resolution, which is very challenging. We presented an ensemble downscaling method for quality improvement of gridded soil moisture data in terms of the accuracy and the spatial resolution by the integration of BMA (Bayesian model averaging) and ATPRK (area-to-point regression kriging). In the experiments, the BMA ensemble showed a 22% better accuracy than the data sets from ESA CCI (European Space Agency-Climate Change Initiative), ERA5 (ECMWF Reanalysis 5), and GLDAS (Global Land Data Assimilation System) in terms of RMSE (root mean square error). Also, the ATPRK downscaling could enhance the spatial resolution from 0.25° to 0.05° while preserving the improved accuracy and the spatial pattern of the BMA ensemble, without under- or over-estimation. The quality-improved data sets can contribute to a variety of local and regional applications related to soil moisture, such as agriculture, forest, hydrology, and meteorology. Because the ensemble downscaling method can be applied to the other land surface variables such as temperature, humidity, precipitation, and evapotranspiration, it can be a viable option to complement the accuracy and the spatial resolution of satellite images and numerical models.

• 디지털융복합연구
• /
• 제14권1호
• /
• pp.479-489
• /
• 2016

본 연구에서는 융합적 장애학의 시각에 근거해 중도 시각장애인의 장애 자부심 구축에 관해 일본 TV드라마 "챌린지드"를 중심으로 주인공 塙와 주변 인물로 나누어 그들의 장애관의 실체를 분석하였다. 이 경우, 연구방법 고론으로서 Priestley(1998)의 장애다중패러다임에 의거한 융합적 장애학을 도모하고자 하였다. 중도시각장애인의 장애자부심 구축과 장애 수용의 패러다임은 근본적으로 상이하다. 그런 면에서 장애수용 이론에 대한 비판은 의료모델에 대한 비판과 통한다. 드라마상에서 장애 자부심의 본질이 가장 두드러진 인물로는 주인공 塙와 교사회장, 교장으로 이들은 사회적 관념론이 체화된 인물로서의 공통점을 보인다. 그 외 인물들의 경우, 초기에는 시각장애교사인 塙의 신체성과 장애 정체성을 부정하지만 이윽고 장애에 대한 사회적 관념론적 시각으로 전화하게 되며, 드라마의 인물들은 완전히 융화된다. 마지막으로 본 연구의 시사점으로는 드라마 자체에 관한 인문학적 사회과학적 분석이라는 내재적 시사와 더불어 드라마를 수단으로 한 교육적 효과와 같은 외재적 시사로 제시하였다.

• 한국화재소방학회논문지
• /
• 제30권5호
• /
• pp.116-123
• /
• 2016

화재모델링을 이용한 목표 대상물의 열적 손상에 대한 정량적 위험성 평가방법이 검토되었다. 이를 위해 대표적인 화재모델로서 FDS가 사용되었으며, 특정 구획 내에서 화원 면적 변화에 따른 전기 케이블의 열적 손상과 관련된 확률이 평가되었다. 보수적 관점에서 적용되고 있는 '최대 손상임계 초과확률'과 손상시간의 정보가 포함된 '손상확률'이 체계적으로 비교되었다. 목표 대상물이 표면온도 및 열유속에 대한 최소 손상기준에 도달하는 순간에 열적 손상이 발생된다는 가정이 적용된 최대 손상임계 초과확률에 비해 본 연구에서 제안된 손상확률은 정량적 화재 위험성을 보다 현실적으로 평가할 수 있음을 확인하였다.

• The Korean Journal of Physiology
• /
• 제17권1호
• /
• pp.29-35
• /
• 1983

The most popular way to get the animal to be co-operative for the animal experimentation is by using some kinds of general anesthetic agents. One of the most important point to take care of is, however, whether the agent(s) to be used is hinder the experimentation itself. There have been many contradictory reports of the general anesthetic agents on the renal function. Moreover, little information on the changes of the renal function by anesthesia has been available. We have done experiments to clarify and compare the effects of anesthesia induced by several general anesthetic agents on renal function in unanesthetized rabbits. Nembutal anesthesia(30 mg/kg, iv.) caused a decrease in free-water clearance, and increase in sodium and chloride excretion without significance. Thiopental anesthesia$(20{\sim}30\;mg/kg,\;iv.)$ suppressed all renal parameters tested. Chloralose(50 mg/kg, iv.) and chloral hydrate(75 mg/kg, iv.) did not change renal functions except for glomerular filtration rate, which parameter was suppressed only for a short period just after agent administration. Urethane(1 g/kg), administered by the route of either subcutaneously or intraperitoneally, suppressed renal functions lasted for the duration of experimental anesthesia. The above data suggest that it is very important to chose an appropriate anesthetic agents for a given experiment, especially experiment involved with renal function, and to interprete the data obtained from the anesthetized animal model for the expected results.