• 한국자동차공학회논문집
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• 제22권7호
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• pp.84-89
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• 2014

Not only the emission regulation of on-road vehicle engine, but also emission regulation of off-road engine have been reinforced. It is the reason of wide application of emission reduction technology for off-road engines. In this study, optimization of engine parameters (Injector hole number, Injection timing and EGR rate) for reduction of NOx and smoke emissions were conducted by using the analysis of sensitivity and S/N ratio of Taguchi method(DOE). As results, this paper shows optimum value of the parameters for NOx and smoke emission reduction. From the result of reproducibility verification, it is final that the prediction value of NOx and smoke has the error of below 10%. Consequently, the method and results of this study will be used for quantitative reference to EGR control mapping in next study.

• 한국정보과학회논문지:소프트웨어및응용
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• 제27권8호
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• pp.846-854
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• 2000

본 논문에서는 대퇴골두 무혈성 괴사의 자동 진단을 위한 효과적인 대퇴골두 영역의 추출 방법을 제안한다. 대퇴골두의 해부학적 특성과 Hough 변환을 이용하여 대퇴골두 영역을 설정하였고, 변형된 영역 확장법을 적용하여 대퇴골두 영역을 분할하였다. 그리고, 분할된 영역으로부터 대퇴골두 무혈성 괴사의 진단에 필요한 인자를 자동으로 측정하였다. 본 논문에서 제안한 영역 추출 방법은 정상적인 대퇴골두와 무혈성 괴사의 초기 단계의 대퇴골두 뿐만 아니라 괴사가 심한 대퇴골두에 대해서도 좋은 결과를 얻을수 있었고, 본 논문에서 제안한 방법으로 측정된 인자는 대퇴골두 무혈성 괴사의 정량적인 분석 및 진단을 가능하게 한다.

• Journal of Welding and Joining
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• 제28권2호
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• pp.54-59
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• 2010

The effects of welding parameters such as contact tip-to-work distance (CTWD), voltage, and current on the weld metal diffusible hydrogen contents (HD) were investigated and rationalized by the calculation of heating time and amount of heat generated in the extension length of flux cored wire. As CTWD increased from 15 to 25mm, HD decreased from 8.46 to 5.45mL/100g deposited metal. Calculations showed that, with an increase of CTWD, the amount of heat generated increased from 46 to 92J in addition to an increase of heating time. Increase of current from 250 to 320A, however, gave little variation of HD. It showed that no significant change in the amount of heat generated was found, and heating time was decreased with an increase of current. It also showed that CTWD is more influential than voltage in relatively lower heat input ranges, while voltage is more in higher input ranges

• Structural Engineering and Mechanics
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• 제72권3호
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• pp.313-327
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• 2019

Damage evolution in the form of void nucleation, propagation and coalescence is the primary cause that is responsible for the ductile failure of microalloyed steels. The Gurson-Tvergaard-Needleman (GTN) damage model has proven to be extremely robust for characterizing the microscopic damage behavior of ductile metals. Nonetheless, successful applications of the model on a given metal type are limited by the correct identification of damage parameters as well as the validation of the calculated void growth rate. The purpose of this study is two-fold. First, we aim to identify the damage parameters of the GTN model for Q345 steel (Chinese code), due to its extensive application in mechanical and civil industries in China. The identification of damage parameters is facilitated by the well-suited response surface methodology, followed by a complete analysis of variance for evaluating the statistical significance of the identified model. Second, taking notched Q345 cylinders as an example, finite element simulations implemented with the identified GTN model are performed in order to analyze their microscopic damage behavior. In particular, the void growth rate predicted from the simulations is successfully correlated with experimentally measured acoustic emissions. The quantitative correlation suggests that during the yielding stage the void growth rate increases linearly with the acoustic emissions, while in the strain-hardening and softening period the dependence becomes an exponential function. The combined experimental and finite element approach provides a means for validating simulated void growth rate against experimental measurements of acoustic emissions in microalloyed steels.

• International Journal of Naval Architecture and Ocean Engineering
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• 제13권1호
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• pp.246-259
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• 2021

IMO stability regulations include various stability parameters such as GM values. To assess the stability of the ships, we should check all stability parameters of the IMO requirements. However, since this process is complex, a more convenient way to evaluate stability performance is required. In this research, the index for marine ship intact stability assessment (IMSISA) model was developed to solve these problems. The IMSISA model consists of a stability index calculation module and a stability assessment module. In the stability index calculation module, ten stability parameters, including GM, were used to develop the stability index, which has the advantage of being able to quantify the ship stability. The stability assessment module uses the stability index value to determine the stability status of the ship and provides the captain with stability management guidelines. To verify the proposed model, the basic stability calculations were performed for two model ships in 32 loading situations. The proposed model was found to provide better performance in the stability assessment than the previous study. By applying the IMSISA model to the ships, the captain can assess the ship stability more quantitatively and efficiently.

• Journal of Acupuncture Research
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• 제29권4호
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• pp.25-34
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• 2012

Objectives : This study was conducted to investigate the effects of fixed-intensity and varied-intensity electroacupuncture in pain and sensory threshold concerning parameters visual analogue scale(VAS), brief pain inventory(BPI) and quantitative sensory testing(QST), among chronic tension headache patients. Methods : Thirty patients with chronic tension headache were randomly assigned to three groups and received different kinds of electroacupuncture at $ST_{36}$ and $ST_{37}$. Group A received fixed-intensity electroacupuncture(fixed-EA), group B received varied-intensity electroacupuncture (varied-EA), and group C received only acupuncture treatment without electrical stimulation as a control group. The intervention was given three times per week, and continued in two weeks. All the experiments were conducted blindly. Results : Fixed-EA group showed a significant decrease of VAS and BPI compared to the baseline measurement, while both varied-EA and control group did not. Of the parameters of QST, subtraction of heat pain threshold(HPT) and cold pain threshold(CPT) slightly increased in all groups, but this was not significant. Conclusions : These results suggest that fixed-EA reduce pain and improve quality of life in patients with chronic tension headache and that acupuncture may regulate patient's pain sensitivity through changing sensory threshold.

• 터널과지하공간
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• 제18권6호
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• pp.465-479
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• 2008

저심도 터널 굴착시 예상되는 암반 거동을 정량적으로 파악하기 위해 계층 분석적 의사결정 방법과 암반 공학 시스템 방법을 적용하여 암반 거동 지수를 산정하였다. 복잡하고 조직화되지 않은 암반 거동을 효과적으로 결정하기 위해 쌍대 비교 매트릭스를 이용하는 계층 분석적 의사결정 방법과 상호 영향 매트릭스를 이용하는 암반 공학 시스템 방법을 적용하였고, 전문가 의견의 불확실성을 극복하고자 퍼지 델파이 방법을 적용하였다. 저심도 암반 터널 굴착 시 예상되는 암반 거동 유형으로 소성 변형, 낙반과 낙석을 제시하였다. 각각의 암반 거동 유형을 결정하기 위해 일축압축강도, 암질 지수와 절리 조건을 포함하는 암반 내생적 매개변수, 응력, 지하수와 지진 조건을 포함하는 암반 외생적 매개변수와 굴착 매개변수를 고하였다. 이를 서울 지하철 O호선 O공구 설계에 적용하여 예상되는 암반 거동 유형을 정량적인 암반 거동 지수로 제시하였다.

• 대한의용생체공학회:의공학회지
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• 제30권2호
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• pp.142-146
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• 2009

The purpose of this study is to investigate the angular velocity of forearm pronation/supination movement in Parkinson's disease patients, as a quantitative measure of the bradykinesia. Thirteen Parkinson's disease patients ($64{\pm}11.0$ yrs, male:6, female:7) participated in the experiments. The subjects' both right and left forearms were scored by a rater according to rapid alternating movement of hands category in the UPDRS (unified Parkinson's disease rating scale) and the angular velocity of forearm pronation/supination was measured at the same time. As analysis parameters, RMS (root mean square) angular velocity and RMS angle were used. The parameters showed negative correlation with the clinical score (RMS angular velocity: r= - 0.914, RMS angle: r= -0.749). The RMS angular velocity of all clinical scales were significantly different one another except for the non significant difference between those of scale 3 and 4. RMS angle of scale 0 was significantly different from those of scale 2, 3, 4 and that of scale 1 was significantly different from those of scale 3 and 4. This suggests that RMS angular velocity can be used for a quantitative measure of bradykinesia in motor examination.

• 대한후두음성언어의학회지
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• 제20권1호
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• pp.42-46
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• 2009

Background and Objectives : Vocal polyps and nodules are representative chronic benign laryngeal disease. Treatment options for vocal polyp and nodule in general include voice therapy or laryngeal microsurgery. The purpose of this study was to analyze voice results before and after laryngeal microsurgery. Materials and Method: Vocal polyp and vocal nodule patients were treated by laryngeal microsurgery from March 2004 to December 2006 at Kosin University Hospital. All were women. Voice analysis studies were done before and after laryngeal microsurgery. Five measurements were performed: MPT, Fo, jitter, shimmer and NHR. Results: There was significant improvement in the vocal polyp patients regarding MPT, jitter, shimmer and NHR. Also there was significant improvement in the vocal nodule patients regarding MPT, jitter and shimmer. Conclusion: MPT, jitter, shimmer and NHR will be effective acoustic parameters in documenting the quantitative changes in the vocal polyp patients. MPT, jitter and shimmer will be effective acoustic parameters in documenting the quantitative changes in the vocal nodule patients before and after laryngeal microsurgery.

• 한국산학기술학회논문지
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• 제17권4호
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• pp.59-73
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• 2016

지하 수송에 대한 수요가 증가함에 따라 도로터널 사용자와 운영자는 다양한 원인에 의한 위험에 노출되어 있으며, 주요 원인은 각각 사고 이벤트가 될 수 있는 교통상황이다. QRA(정량적 위험평가)의 중요성은 도로터널의 안전성을 정량화하고, 다수의 이해관계자들의 관점(용량, 신뢰성, 가용성, 유지보수 및 안전)에서의 요구조건에 밸런스를 유지하려는 의도에서 커지기 시작했다. 위험평가에 사용되는 고전적 방법은 ETA, FTA이지만, 변수의 다양함과 상호관계를 반영하지 못한다는 이유에서 이 방법들은 상대적으로 단순한 경우에만 적용할 수 있다. 특정위험평가에 필요한 객체, 이벤트, 결과 및 가정, 경계조건 등의 총체는 도로 터널시설 위험평가를 위해 필수적인 내용으로 관찰되어야 하는 시스템을 만들고, 정보, 데이터, 모델 등 관련 항목들이 그 시스템을 서술하게 된다. 시스템은 위험모델에 기반한 계층적 지표들을 사용하여 모델링되고 분석되며, 시스템의 모든 가능한 구성은 지표의 적절한 선택을 통하여 표현될 수 있다. 따라서 본 연구에서는 일반터널에서뿐만 아니라 복층터널 같은 복합적인 지하시스템 변수들간의 상호의존성을 고려하여 정량화할 수 있는 베이지안 네트워크를 근거로 한 정량적 위험평가방법을 소개한다.