• Proceedings of the Korean Information Science Society Conference
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• 1999.10a
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• pp.554-556
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• 1999

소프트웨어 품질 향상과 생산성 향상이라는 측면에서 소프트웨어 재사용의 중요성이 널리 인식되어지고 그에 따른 재사용 컴포넌트에 대한 관심이 나날이 커져가고 있다. 이에 따라 재사용성을 측정하는 방법에 대한 연구의 중요성이 커지고 있다. 본 논문에서는 기존의 결합도를 측정하는 방법을 변형하여 두 클래스간의 의존 정도를 측정하고 클래스를 노드로, 측정한 의존 정도를 예지 값으로 하는 방향 그래프를 그린다. 그리고 그 그래프를 클러스터링을 하여 재사용 컴포넌트의 후보를 추출하는 방법을 제시한다.

• Journal of Oral Medicine and Pain
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• v.30 no.3
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• pp.375-381
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• 2005

Er:YAG laser has been considered a promising alternative to dental drill and many researches indicate that adjustment to variable parameters, including water flow rate, pulse energy and pulse repetition rate, can be made to improve ablation ability and efficiency of the laser. Of these parameters, addition of water spray during irradiation has been thought to ablate dental hard tissue more rapidly and safely. The purpose of this study was to investigate tooth ablation amount by Er:YAG laser irradiation as related to varied water flow rates added and, ultimately to find the most effective water flow rate for ablation. In addition, the temperature change of pulp chamber during irradiation was also monitored on the irradiated and opposite pulpal walls, respectively. An Er:YAG laser with contact mode was employed. Extracted human molars were split into two pieces for ablation experiment. Pulse energies of 200 and 300 mJ with a pulse repetition rate of 20 Hz and 5 water flow rates (1.6, 3.0, 5.0, 7.0, and 10.0 ml/min) were applied. Each irradiation was performed for 3 seconds. According to these parameters, experimental groups were divided into 10 subgroups which consisted of 5 specimens. For temperature experiment, another 5 tooth-specimens were prepared in the manner that pulp chamber was open through access cavity preparation and two temperature-measuring probes were placed respectively on the irradiated and the opposite walls of pulp chamber. From the experiment on ablation amount related to different water flow rates, it was shown that the least water flow rate of 1.6 ml/min ablated more than any other water flow rates (p<0.000). When the irradiation for 3 seconds, combined with the pulse repetition time of 20Hz and the water flow rate of 1.6 ml/min was done to tooth specimen, the temperature rise was not noticeable both on the irradiated and the opposite pulpal walls (less than 3$^{\circ}C$) and there was no significant difference in temperature rise between the two pulse energies, 200 and 300 mJ. From the results of this study, it is suggested that tooth ablation with Er:YAG laser can be done effectively and safely at a energy between 200 and 300 mJ/pulse and a pulse repetition rate of 20 Hz when the lasing is conjugated with the water flow rate of 1.6ml/min.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.1
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• pp.89-96
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• 2022

In this paper, to evaluate the output quality of the cementitious composite mixture for printing with the ME method for construction 3D printer, visual inspection of the output appearance and the dimensional error rate, compressive strength and flexural strength of the output were measured. As a result of the test, the mixing design with excellent output appearance was P1-2, P1-4, P2-5, P2-6, and the mixing design with good output appearance was P0-1, P1-1, P1-3, P1-6, P1-7 and P2-4. Of these mixing designs, P0-1 and P2-6 had the lowest dimensional error rates As a result of evaluating the compressive strength and flexural strength of the various mixing designs, the Mixing design with excellent output designs showed good mechnical properties. However, mixing designs with excellent mechanical properties does not necessarily have excellent output quality. Therefore, in order to accurately evaluate the output quality, it is judged that visual inspection and dimensional error rate inspection should be performed first, and then the mechanical characteristics should be reviewed.

• Restorative Dentistry and Endodontics
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• v.30 no.3
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• pp.193-203
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• 2005

The induction of the IL-8 and MCP-1 by the stimulation of Substance P and TNF-${\alpha}$ (IL-8 agonist) and the specificity for SP using Spantide (SP antagonist) in the dental pulp tissues was measured quantitatively. In addition, the secretion of the IL-8 in the human dental pulp tissue 36 hrs after the stimulation of SP was observed after the stimulation of SP qualitatively. According to this study the results were as follows: 1. There was the significant IL-8 induction at 36 h after SP (10$^{-4}$M) stimulation of the pulp tissue comparing with the unstimulated dental pulp tissues (p < 0.05) . IL-8 irnmunostaining was weakly detected along the periphery of the pulp tissue after Mock stimulation and IL-8 immunostaining was detected around the fibroblast in the pulp tissue 36h After SP (10$^{-4}$M) stimulation, 2. The secretion of MCP-1 from the dental pulp tissues comparing with Mock stimulation was induced at 36 hrs after TNF-$\alpha$ (40 ng/ml) stimulation, but no induction with SP(10$^{-4}$M) TNF-${\alpha}$ (40 ng/ml) did not induce the IL-8 secretion from the pulp tissue, weak IL-8 imrnunostaining was detected along the periphery of the pulp tissue 3. Spantide (10$^{-5}$M) inhibited IL-8 induction from the pulp tissues 36 h after SP (10$^{-4}$M) stimulation These results suggest that SP significantly induces IL-8 recruiting neutrophils in localized human dental pulp tissue MCP-1 appears to be less involved in the early establishment of pulpal inflammation in response to irritation such as mechanical insult of dentin. SP may have positive relation with the inflammation of the human dental pulp tissues.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.9
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• pp.916-922
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• 2008

Structures being used in space environment, should be designed to have minimum CTE(coefficient of thermal expansion) for the dimensional stability. Accurate CTE data of the materials are required to design the space structures consisting of various materials. There are uncertainties in the characteristics of materials even though the same manufacturing processes are applied. Therefore, it is needed to measure the thermal deformation of not only the material specimen but also substructures in simulated space environment, such as high vacuum condition. In this research, therefore, precise CTE measurement system using displacement measuring interferometer and vacuum chamber has been designed with uncertainty analysis of the measurements. This system can be used to measure the CTE of the specimen or thermal expansion of the substructure with varying size up to 50cm in length. To measure the low CTE material, overall uncertainty of this system is expected under 0.01ppm/K.

• Journal of the Korean Society for Nondestructive Testing
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• v.25 no.2
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• pp.74-80
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• 2005

A new dimension measuring method for the measurement of diameter of an object has been developed using laser triangulation. The 3D data of an object was calculated from the 2 dimensional image information obtained by the laser stripe using the laser triangulation. The system that use existing theory can measure the diameter of hole not only in a normal plane but also ill an incline plane. However, in the existing theory, since the lens with fixed feral length was used, the area of measurement was fixed. The simplest way to solve this problem is to change distance between a CCD camera and object. Other way is to use a zoom lens having variable focal length. In this paper, the zoom lens with variable focal length was used. Therefore, we ran experiment with magnification that is optimized according to size of object using zoom lens with variable focal length.

• Proceedings of the KAIS Fall Conference
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• 2011.05a
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• pp.292-295
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• 2011

본 논문에서는 배수성(저소음)포장을 포함하는 2-Layer 아스팔트 포장의 상부층과 하부층의 역학적인 특성을 평가하는데 목적이 있다. 연구 방법으로는 슈퍼페이브 배합설계로 2-Layer 아스팔트 포장의 상 하부층 시편을 제작하였으며, 시편 상부층의 최대공칭치수는 4.75mm이고 하부층의 최대공칭치수는 13mm이다. 이 시편에 대한 기본 물성 시험 실시 후 마샬 안정도 시험에 대한 안정도와 흐름값을 평가하였다. 그리고 상부층과 하부층의 자유단 공진주 시험을 통해 탄성계수(E)를 측정하였고, 비파괴 시험법인 슈미트해머(Schmidt hammer)를 이용해 반발경도를 측정한 후 강도를 추정하였다. 또한 일축압축시험으로 측정된 압축강도로 탄성계수($E_{50}$)를 계산하였다. 마지막으로 각각의 역학적 시험을 통해 얻어진 결과값으로 강도(qu)와 탄성계수 ($E_{50}$)의 상관관계와 추정식으로 구한 강도와 일축압축강도 시험으로 얻어진 강도와의 상관관계를 분석하였고, 자유단 공진주 시험의 탄성계수(E)값과 일축압축시험의 결과로 얻어진 탄성계수($E_{50}$)의 상관관계를 분석하였다.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.4
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• pp.87-92
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• 2009

쇽옵서버 피스톤로드(shock absorber piston rod)는 자동차의 충격과 진동의 흡수에 작용하는 자동차 현가장치(suspension equipment)부품의 일종이다. 피스톤로드는 자동차 충격흡수에 매우 밀접한 영향을 주기 때문에 제조에 있어서 고도의 정밀도와 표면 매끄러움이 요구된다. 피스톤로드의 제조공정은 선삭, 홈가공, 밀링, 전조 등 여러 공정으로 구성되는데, 여기서 품질불량에 가장 크게 영향을 주는 공정은 선삭공정(lathing process)이다. 이는 선삭공정의 가공공구(insert component)가 주원인으로서 반복되는 가공으로 인한 공구의 마모(abrasion)나 파손(breakage)이 주요 원인으로 지적되고 있다. 따라서 가공 데이터를 수집 분석하여 공구의 교체시기를 파악한다거나 가공 부품의 측정 데이터가 관리도 상하한선 내에 있는지 등 가공 공정 전반에 대한 체계적인 공정관리 시스템 개발이 요구된다. 본 연구에서는 자동차 쇽업서버 피스톤로드 제조공정의 가공 정보를 체계적으로 수집하여 관리하고 분석하는 자동차 쇽업서버 피스톤로드 제조공정에 대한 공정관리시스템을 개발하는 것이 목적이다. 개발결과 피스톤 로드의 측정 치수 변화 및 불량발생을 측정, 감지할 수 있었으며, 본 시스템을 통해 가공공구의 치수오차를 보정(compensation)하고 공정의 불량발생을 조기에 방지 함으로써 불량률은 1/5로 경감하고 작업자 수도 1/2로 감소시킬 수 있었다.

• Journal of Conservation Science
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• v.8 no.1 s.11
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• pp.28-32
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• 1999

The performance of dimensional stabilization of lactitol, PEG (Mw, 4000), and sucrose was evaluated for thin sections of oak wood (Quercus sp.) that had been buried in underground for presumably 1500 years. Thin wood sections of the specimen were soaked for three and seven days in each stabilizing agent with wide concentration ranges of 10, 30, 50, and $70\%$ by weight. Sucrose showed the largest weight gain among three agents, and the shrinkage of cross sections were found to be $1\%\;and\;4\%$ for three and seven days soaking, respectively. The result showed that sucrose among three stabilizing agents used was the best for the dimensional stabilization of the oak wood.

• Journal of the Korean Wood Science and Technology
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• v.39 no.3
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• pp.206-212
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• 2011

It was investigated the hardness and dimensional stability of heat-compressed wood by compression temperature and time. The surface hardness of heat-compressed wood increased with increasing compression temperature. The lowest hardness value (5.0 N/$mm^2$) was observed in the temperature $70^{\circ}C$ while the highest value (15.6 N/$mm^2$) was obtained in compression temperature $220^{\circ}C$. Dimensional recovery test results showed that fixation of compression set improved with increasing compression temperature. However, the fixation effects were negligible by press time. Contact angle increased with increasing press temperature and time.