• Journal of Periodontal and Implant Science
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• 제31권3호
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• pp.531-542
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• 2001

Periodontal debridement is most important procedure in periodontal treatment, because periodontal disease is the biofilm infection. The use of ultrasonic instrument has many clinical advantages compared to classical hand instrument. The introduction of newly developed ultrasonic scaler tips made the use of ultrasonic scaler popular. However the study of tooth substance removal according to the working parameters of ultrasonic scaler with newly developed tips is not sufficient. The purpose of this study is to evaluate the effects of working parameters of piezoelectric ultrasonic scaler with curette tip on casting gold removal. The working parameters was standardized by the sledge device which controls lateral force(0.5 N, 1.0 N, 2.0 N) and power setting was adjusted 2, 4, 8 in P mode and S mode and instrumentation time was 5 seconds. The defect depth and width were measured with profile meter and defect surface was examined by SME. The depth of defect was significantly large in S mode( $39.58{\pm}19.35{\mu}m$) compared to P mode( $8.37{\pm}6.98{\mu}m$). There was significant decrease of depth of defect between 1.0N($32.87{\pm}27.18{\mu}m$) and 2.0N( $14.86{\pm}15.04{\mu}m$). The area of defect was also significantly large in S mode($4482.42{\pm}3551.71{\mu}m^2$) compared to P mode( $922.06{\pm}960.32{\mu}m^2$). There was significant decrease of area of defect between 1.0N($3889.12{\pm}3936.00{\mu}m$) and 2.0N( $974.66{\pm}986.01{\mu}m$). The change of mode did not effect on the width of the defect. The change of power setting did not effect on the depth, width, and area of defect. In spite of limitation of this study it could be concluded that the use of piezoelectric ultrasonic scaler with curette tip on S mode could make significant tooth substance loss.

• 한국재료학회지
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• 제18권8호
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• pp.427-431
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• 2008

The mechanical property of a phosphore layer was investigated by measuring the resolution (LP/mm) and by positron annihilation spectroscopy and SEM. Image plate samples containing the phosphore layer were irradiated by X-rays in a hospital numerous times over a course of several years. The LP/mm values of a (Ba,Sr)FBr : Eu image plate irradiated by X-rays varied between 2.2 and 2.0 over a period of four years. Coincidence Doppler Broadening (CDB) positron annihilation spectroscopy was used to analyze defect structures. The S parameters of the samples from hospital use varied from 0.6219 to 0.6232. There was a positive relationship between the time of exposure to the X-rays and the S parameters. Most of the defects were found to have been generated by X-rays.

• 제어로봇시스템학회논문지
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• 제6권2호
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• pp.207-216
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• 2000

This paper introduces an effective system design method to develop a customer oriented product using a design optimization process and to select a set of critical design paramenters,. The process results in the development of a successful product satisfying customer needs and reducing development risk. The proposed scheme adopted a five step QFD(Quality Function Deployment) in order to extract design parameters from customer needs and evaluated their priority using risk factors for extracted design parameters. In this process we determine critical design parameters and allocate them to subsystem designers. Subsequently design engineers develop and test the product based on these parameters. These design parameters capture the characteristics of customer needs in terms of performance cost and schedule in the process of QFD, The subsequent risk management task ensures the minimum risk approach in the presence of design parameter uncertainty. An application of this approach was demonstrated in the development of weld quality monitoring system. Dominant design parameters affect linearity characteristics of weld defect feature vectors. Therefore it simplifies the algorithm for adopting pattern classification of feature vectors and improves the accuracy of recognition rate of weld defect and the real time response of the defect detection in the performance. Additionally the development cost decreases by using DSP board for low speed because of reducing CPU's load adopting algorithm in classifying weld defects. It also reduces the cost by using the single sensor to measure weld defects. Furthermore the synergy effect derived from the critical design parameters improves the detection rate of weld defects by 15% when compared with the implementation using the non-critical design parameters. It also result in 30% saving in development cost./ The overall results are close to 95% customer level showing the effectiveness of the proposed development approach.

• International Journal of Naval Architecture and Ocean Engineering
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• 제12권1호
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• pp.578-595
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• 2020

Submarine pressure hulls must withstand high hydraulic pressure and be free of defects. To improve the precision of defect detection, we herein examined different probes for optimal defect assessment by applying the Phased Array Ultrasonic Testing (PAUT) method. Two sets of probe design parameters were selected by considering pressure hull characteristics and analyzed through modeling. PAUT probes were applied, and defect assessment results were compared based on ultrasonic signals of various simulated defects in specimens designed to be the same as actual pressure hulls. The final selected design parameters for the submarine probe, which were designed to minimize the grating lobe of wave interference effect and improve the ultrasonic resolution of pressure hull welds, were identified through the experiment. The improvement in the probe's ability to detect defects in a pressure hull was verified. Furthermore, the accuracy of defect length measurement was improved, enhancing the applicability of the technique.

• 소성∙가공
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• 제19권8호
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• pp.486-493
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• 2010

A shape error of the sheet metal product made by a flexible stretch forming process is occurred by a various forming parameters. A die used in the flexible stretch forming is composed of a punch array to obtain the various objective surfaces using only one die. But gaps between the punches induce the shape error and the defect such as a scratch. Forming parameters of the punch size and the elastic pad to prevent the surface defect must be considered in the flexible die design process. In this study, tendency analysis of shape error according to the forming parameters in the flexible stretch process is conducted using a finite element method. Three forming parameters, which are the punch size, the objective curvature radius and the elastic pad thickness, are considered. Finite element modeling using the punch height calculation algorithm and the evaluation method of the shape error, which is a representative value for the formability of formed surface, are proposed. Consequently, the shape error is in proportion to the punch size and is out of proportion to the objective curvature radius and the elastic pad thickness.

• Bulletin of the Korean Chemical Society
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• 제30권4호
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• pp.891-896
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• 2009

Giusti-Suzor and Fano introduced translations of the scales of Lu-Fano plots by phase renormalization in order to decouple the intra- and inter-channel couplings in multichannel quantum defect theory (MQDT). Their theory was further developed by others to deal with systems involving a larger number of channels. In different directions, MQDT was reformulated into forms with a one-to-one correspondence to those in Fano's configuration mixing theory of resonance for photofragmentation processes involving one closed and many open channels. In this study, the theory was further developed to fully reveal the coupling nature, decoupling of the background and resonance scattering in physical scattering matrices as well as to further extract the dynamic parameters undiscovered by Fano and his colleagues. This theory was applied to the photoabsorption spectrum of $H_2$ observed by Herzberg's group.

• 한국항해항만학회지
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• 제28권1호
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• pp.43-49
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• 2004

결함검사는 생산공정에 있어서 상품의 디자인과 함께 매우 중요한 부분으로서, 상품의 경쟁력을 높이는데 필수 불가결한 것이다. 만약, 실시간 결함검출이 상품에 대한 어떤 손상도 없이 할 수 있다면, 품질 및 공정의 효율적 관리와 고비용 인력의 절감을 통하여 생산원가를 줄일 수 있다. 본 논문에서는 철판과 같은 표면에 결함이 있는 경우 필요한 정보만을 추출할 수 있는 3가지 공간필터법에 대하여 제안하였고, 공간필터의 특성을 통하여 결함검출 시스템을 구성하였다. 그리고, 최적의 표면결함 계측용 공간필터법을 개발하기 위하여 결함의 크기와 형태, 광도의 크기 및 외부 광간섭 그리고 슬리트의 개수와 같은 파라메타의 변화에 따른 측정 성능을 비교 및 분석하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.437-438
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• 2006

Generally, the vertical roll process is used to achieve extensive width reduction in hot strip mill. However, it is difficult to avoid the defects such as dog-bone and seam-defect. The sizing press has been developed in response to the defects mentioned above. Especially, this study is carried out to investigate the deformation of slab by two-step sizing press. The deformation behavior in the width sizing process is more favorable than that in conventional vertical rolling edger. The objective of this study is to determine the optimal anvil shape parameters in the sizing press with two-step die from the viewpoint of edge-seam length. In general, the edge-seam defect occurs parallel to the rolling direction at both edges in horizontal rolling process after sizing press. The optimal combination of the parameters is determined by FE-simulation and Artificial Neural Network (ANN). The slab deformation in sizing press with convex anvil is analyzed by FE-simulation. The most suitable profile of the anvil is also discussed fur the improvement of trimming loss because of the side seam defect by FE-simulation and ANN.

• 정보처리학회논문지D
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• 제15D권3호
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• pp.313-320
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• 2008

전형적인 소프트웨어 생명주기 모델은 결점이 추가되거나 제거되는 단계들의 일련의 순서로 구성되어 있다. 우리가 원하는 수준의 품질을 달성하기 위해서는 소프트웨어 개발 전 과정에서 결점 제거를 수행하여야 한다. 잘 알려진 단계기반 결점 프로파일은 Gaffney 모델이 있다. 이 모델은 결점 제거 프로파일이 Rayleigh 분포를 따르며 단계 인덱스 번호를 모수로 하고 있다. 실제 개발되는 소프트웨어에 Gaffney 모델을 적용시 제거된 결점이 최대값이 되는 점을 위치 모수가 표현하지 못하는 문제가 있다. 그러므로 Gaffney 모델은 실제 결점 프로파일을 표현하지 못한다. 본 논문은 2개의 다른 모델을 제시한다. 하나는 수정된 Gaffney 모델로 위치 모수를 교체하기 위해 Putnam의 SLIM 모델의 모수를 도입하였다. 다른 하나는 누적 결점 프로파일이 S자 형태를 보여 성장곡선 모델을 제시하였다. 제안된 모델은 5개의 다른 소프트웨어 프로젝트로부터 얻어진 결점 프로파일 분석에 의해 검증하였다. 실험 결과 제안된 모델이 Gaffney 모델 보다 좋은 결과를 얻었다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권3호
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• pp.127-133
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• 2006

This Paper describes a dual bands PD measurement method which has two different bandwidths. The one bandwidth is 0.5 - 2 GHz and the other is 1 - 2GHz. This method is used for GIS diagnosis. In the experiment, it shows that the ratios between two PD quantities in dual bands depend on the defect types and gas pressures. The variations of ratios in different pressures are more sensitive than ones in defect types. And These ratios increase with increasing SF6 gas pressures. As these ratios give us additive information of PD we can analyze the defect type as well as risk assessment for the GIS reliably. Therefore the above result shows that these ratios are one of parameters for diagnosing GIS.