• 한국생산제조학회지
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• 제8권6호
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• pp.55-63
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• 1999

The acceleration of the performance of machine tools influences the development of the semi-conductor and optical technology as the development of NC and measurement technology. Because the measurement has been done to unload condition without considering of mechanical stiffness in the case of machining center as we measure the quasi-static error of machine tools on general study people who works on the spot has many problems on the data value. Also there are no satisfiable results until now in spite of many studys about this because the deflections of the table and the shaft supporting a workpiece influence, influence the accuracy of the table and shaft supporting a workpiece influence the accuracy of the workpiece. And there is doubt about the inspection method of measured error. In this paper Therefor we will help working more accurately on the spot by measuring analyzing displaying the defoec-tion of the table and support shaft when we load on the table and the support shaft of machining center using laser interfer-ometer. Also we try to settle new conception of the measurement method and more accurate grasp of the deflection tenden-cy by verifing the tendency of the error measured through the comparison of the simulated error measured through the comparison of the simulated error using ANSYS a common finite element analysis program which is able to measure heat deformation material deformation and error resulted from this study.

• 대한기계학회논문집A
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• 제27권8호
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• pp.1418-1425
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• 2003

In CAD systems, a surface to be machined is expressed by a series of curves, such as B-spline, Bezier and NURBS curves, which compose the surface and then in CAM systems the curves are divided into a large number of line or arc segments. These divided movement commands, however, cause many problems including their excessive size of NC data that makes almost impossible local adjustment or modification of the surface. To cope with those problems, the necessity of real-time curve or surface interpolators was embossed. This paper presents an efficient real-time tool-path generation method fur interpolation of NURBS surfaces in CNC machining. The proposed tool-path generation method is based on an improved iso-scallop strategy and can provide better precision than the existing methods. The proposed method is designed such that tool-path planning is easily managed in real-time. It proposed a new algorithm for regulation of a scallop height, which can efficiently generate tool-paths and can save machining time compared with the existing method. Through computer simulations, the performance of the proposed method is analyzed and compared with the existing method in terms of federate, total machining time and a degree of constraint on the scallop height.

• 한국정밀공학회지
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• 제20권12호
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• pp.25-33
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• 2003

A burr has been defined as undesirable projection of material formed as a result of plastic flow from a cutting or shearing operation. It is unavoidable in all kinds of machining operation. As a result, burr makes troubles on manufacturing process due to deburring cost, quality of products and productivity. In this study, the primary interest is about exit burr. The burr formation mechanism in each type of burr is classified. Data bases are developed to predict burr formation result. In the milling operation, we develop an algorithm to analyze the burr formation mechanism by the geometrical analysis on the multi featured workpiece with multi cutting path. The algorithm includes three steps, i. e., the feature identification, the cutting condition identification, and the analysis on exit burr formation. We can predict which portion of workpiece would have the exit burr in advance so that we can manage to find a way to minimize the exit burr formation in an actual cutting. Also, this algorithm can be implemented in a commercial CAM package so that we can simulate the NC code to review the burr formation in advance.

• 대한의용생체공학회:의공학회지
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• 제35권3호
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• pp.68-74
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• 2014

Recent research on mild cognitive impairment (MCI) has shown that cognitive and memory decline in this disease is accompanied by disruptive changes in the brain functional network. However, there have been no graph-theoretical studies using $^{11}C$-PIB PET data of the Alzheimer's Disease or mild cognitive impairment. In this study, we acquired $^{18}F$-FDG PET and $^{11}C$-PIB PET images of twenty-four normal aging control participants and thirty individuals with MCI from ADNI (Alzheimer's Disease Neuroimaging Initiative) database. Brain networks were constructed by thresholding binary correlation matrices using graph theoretical approaches. Both normal control and MCI group showed small-world property in $^{11}C$-PIB PET images as well as $^{18}F$-FDG PET images. $^{11}C$-PIB PET images showed significant difference between NC (normal control) and MCI over large range of sparsity values. This result will enable us to further analyze the brain using established graph-theoretical approaches for $^{11}C$-PIB PET images.

• 대한기계학회논문집A
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• 제20권8호
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• pp.2508-2515
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• 1996

Determination of an optimal feed rate is valuable in the sense of the precision and efficient machining. In this regard, a new surface roughness model for the face milling operation that considered the radial and axal runouts of the inserts in the cutter body was developed. The validity of the model was proved through the cutting experiments, and the model is able to predict the real machined surface roughness exactly with the information of the insert runouts and the cutting conditions. From the estimated surface roughness value, the maximum feed rate that obtains a maximum naterial removal rate under the given surface roughness constraint can be selected by using a bisection method. Therefore, this mehod for optimizing the feed rate can be well applied to the using a bisection method. Therefore, this method for optimizing the feed rate can be well applied to the using selsction of the cutting condition during the NC data generation in CAM.

• 대한기계학회논문집
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• 제12권6호
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• pp.1227-1237
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• 1988

본 연구에서는 Fig.1은 본 시스템이 제품의 형상을 모델링하고 그것으로부터 어떻게 금형을 설계하는 지를 설명해주고 있다. 본 연구의 범위는 Fig.1의 점선에 의해 둘러 싸인 부분이다. 즉 본 시스템의 모델링 기능을 사용하여 생성시킨 최종제 품 형상으로부터 적당한 몰드 베이스와 그에 장착되는 금형판을 설계 생성시키는 작업 이다.수지의 유동 해석과 NC공구 경로의 계산은 개발 중에 있으며 이들과 함께 통 합되면 완전한 CAD/CAM 시스템을 Fig.1에서와 같이 구축할 수 있다.

• Biomolecules & Therapeutics
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• 제25권2호
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• pp.165-170
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• 2017

Cordyceps bassiana is one of Cordyceps species with anti-oxidative, anti-cancer, anti-inflammatory, anti-diabetic, anti-obesity, anti-angiogenic, and anti-nociceptive activities. This mushroom has recently demonstrated to have an ability to reduce 2,4-dinitrofluorobenzene-induced atopic dermatitis symptoms in NC/Nga mice. In this study, we further examined phytochemical properties of this mushroom by column chromatography and HPLC analysis. By chromatographic separation and spectroscopic analysis, 8 compounds, such as 1,9-dimethylguanine (1), adenosine (2), uridine (3), nicotinamide (4), 3-methyluracil (5), 1,7-dimethylxanthine (6), nudifloric acid (7), and mannitol (8) were identified from 6 different fractions and 4 more subfractions. Through evaluation of their anti-inflammatory activities using reporter gene assay and mRNA analysis, compound 1 was found to block luciferase activity induced by $NF-{\kappa}B$ and AP-1, suppress the mRNA levels of cyclooxygenase (COX)-2 and tumor necrosis factor $(TNF)-{\alpha}$. Therefore, our data strongly suggests that compound 1 acts as one of major principles in Cordyceps bassiana with anti-inflammatory and anti-atopic dermatitis activities.

• 대한건축학회논문집:구조계
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• 제34권5호
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• pp.59-67
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• 2018

G-SEED's evaluation of existing buildings is an important point because the energy consumption and CO2 emissions of existing buildings are continuously increasing due to the aging of buildings over time. However, as G-SEED certification is concentrated on new buildings and the standards are not yet available, we will make improvements to evaluate the existing buildings of G-SEED. In order to improve G-SEED for EB, two research procedures were carried out. First, LEED EBOM and LEED for NC compare and analyze evaluation items and methods, and LEED EBOM focuses on evaluation of existing buildings. Second, we analyzed the certification evaluation contents of eight domestic LEED EBOM accredited buildings and obtained items that can be applied or need to be applied when revising G-SEED for EB. LEED EBOM is focused on improving the performance and utilization of data that track and manage the energy and environmental effects of building operations. As a result of the case analysis, the evaluation of G-SEED for EB requires quantitative evaluation items such as environmental management of buildings, energy performance status of building, improvement plan and improvement of performance according to tracking value. Although G-SEED for EB is not structured yet and there are few cases of certification, it is expected that quantitative evaluation of existing buildings will be made through continuous research.

• 반도체디스플레이기술학회지
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• 제21권3호
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• pp.50-56
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• 2022

In order to process a vast amount of data, there is demand for a new system with higher processing speed and lower energy consumption. To prevent 'memory wall' in von Neumann architecture, RRAM, which is a neuromorphic device, has been researched. In this paper, we summarize the features of RRAM and propose the device structure for characteristic improvement. RRAM operates as a synapse device using a change of resistance. In general, the resistance characteristics of RRAM are nonlinear and random. As synapse device, linearity and uniformity improvement of RRAM is important to improve learning recognition rate because high linearity and uniformity characteristics can achieve high recognition rate. There are many method, such as TEL, barrier layer, NC, high oxidation properties, to improve linearity and uniformity. We proposed a new device structure of TiN/Al doped TaO_x/AlO_x/Pt that will achieve high recognition rate. Also, with simulation, we prove that the improved properties show a high learning recognition rate.

• 한국작물학회지
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• 제27권1호
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• pp.84-86
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• 1982

담배의 품종과 재배형별 주당 건물중의 경시적 변화를 보다 더 정밀하게 표현할 수 있는 생장곡선방정식을 수식화하기 위하여 3가지의 생장모형을 만들어서 그 타당성을 분석한 결과는 다음과 같다. 1. 담배의 건물중에 가장 적합한 생장곡선은 C형이며 이 생장곡선은Y = A + (1-$\sqrt{4AK+1}$)/2이다. 2. 이 곡선은 이식후 35-55일의 편차가 Logistic curve보다 더 작으며 정밀하다.