• 대한기계학회논문집
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• 제17권1호
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• pp.1-10
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• 1993

본 연구에서는 치차의 소음은 근본적으로 치형에 관계된 것으로 생각하여 치 차소음을 감소시키기 위해 제시한 방법에 적합한 치형, 즉 물림률을 증가시킬 수 있고 동시에 치형수정의 효과를 나타내며, 미끄럼률.치면접촉응력.이뿌리응력이 작은 인벌 류트-사이클로이드 하벙치형을 유효치형으로 하여 저소음 치차의 치형을 치차의 소음 을 감소시키기에 적절한 치형설계조건을 설정하여 설계한다. 설계한 합성치형치차의 소음저감성능을 확인하기 위해 치형을 생성시키는 컴퓨터프로그램의 치형데이터를 이 용하여 합성치형치차, 인벌류트치차, 그리고 사이클로이드치차를 NC Wire Cutting Ma- chine으로 가공하고 각 치차에 대해 소음측정실험을 하여 소음레벨을 비교검토한다.

• 한국통신학회논문지
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• 제29권7B호
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• pp.711-721
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• 2004

To provide the end-to-end service differentiation for assured services, the random early demotion and promotion (REDP) marker in the edge router at each domain boundary monitors the aggregate flow of the incoming in-profile packets and demotes in-profile packets or promotes the previously demoted in-profile packets at the aggregate flow level according to the negotiated interdomain service level agreement (SLA). The REDP marker achieves UDP fairness in demoting and promoting packets through random and early marking decisions on packets. But, TCP fairness of the REDP marker is not obvious as fur UDP sources. In this paper, to improve TCP fairness of the REDP marker, we combine a dropper with the REDP marker. To make packet transmission rates of TCP flows more fair, at the aggregate flow level the combined dropper drops incoming excessive in-profile packets randomly with a constant probability when the token level in the leaky bucket stays In demotion region without incoming demoted in-profile packets. It performs a dropping in the demotion at a domain boundary only if there is no prior demotion. The concatenate dropping at multiple domains is avoided to manifest the effect of a dropping at a domain boundary on TCP fairness. We experiment with the REDP marker with the combined dropper using ns2 simulator for TCP sources. The simulation results show that the REDP marker with the combined dropper improves TCP fairness in demoting and promoting packets by generating fair demoted in-profile traffic compared to the REDP marker. The effectiveness of the selected drop probability is also investigated with showing its impact on the performance of the REDP marker with the combined dropper.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 춘계학술대회 논문집
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• pp.70-73
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• 2004

The approach in this thesis is for prediction of deformed strip profile in hot rolling mill. This approach shows how to make an expression as a mathematical form in predicting strip profile. This approach is based on the velocity field, shear stress and material flow on the strip edge along width direction and lateral displacement and stress along width are analytically calculated. Roll force is calculated in each section and then combined together to show roll force distribution along width. All the assumptions to make equation form for this approach are supported by FEM simulation result and the result of model is verified by FEM result. So, this model will supply very useful tool to the researcher and engineers which takes less time and has similar accuracy in predicting roll force profile comparing to FEM simulation. This model has to be combined with deformed roll profile model, which include thermal crown prediction and wear prediction model to predict deformed strip profile.

• 한국정밀공학회지
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• 제14권12호
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• pp.135-142
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• 1997

New approach to determine thd design of automotive tire profile was introduced. In this study, design technology for tire profile was combined with a finite element method to improve high speed durability. Static and dynamic behavior analysis of new concept tire was compared with conventional tire profile. To obtain the improved tire performance, appropriate design values, ie. design methodology, section profile selection, material properties, are needed.

• 조명전기설비학회논문지
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• 제28권5호
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• pp.82-91
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• 2014

The combined generator system by integrating several renewable energy sources can share the electrical infrastructure and therefore have the advantage of constructing not only the transmission system but also the power conversion system. Among the various combined renewable system, the wind power and wave power has a high possibility of future growth due to the economic feasibility in offshore environment. This kind of large-scale combined systems might be follow the determination by the transmission system operator's directions and control the output profile by focusing at PCC. However, both renewable energies are depend on the unpredictable environmental variation; it is needed to do the compensation devices. In this paper, the ESS compensation plan is proposed to do output determination of the combined generator system by paying attention to active power of utility grid with the analysis of the controllable elements of the wind and wave power generator. The improvement of the new application technique of the combined system is confirmed through using the PSCAD/EMTDC. The entire simulation process was designed by adopting the active power control according to the reference signal of TSO.

• 한국통신학회논문지
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• 제29권1B호
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• pp.86-100
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• 2004

To provide the end-to-end service differentiation for assured services, the random early demotion and promotion (REDP) marker in the edge router at each domain boundary monitors the aggregate flow of the incoming in-profile packets and demotes in-profile packets or promotes the previously demoted in-profile packets at the aggregate flow level according to the negotiated interdomain service level agreement (SLA). The REDP marker achieves UDP fairness in demoting and promoting packets through random and early marking decisions on packets. But, TCP fairness of the REDP marker is not obvious as for UDP sources. In this paper, to improve TCP fairness of the REDP marker, we propose a modified REDP marker where we combine a dropper, meters and a token filling rate configuration component with the REDP marker. To make packet transmission rates of TCP flows more fair, at the aggregate flow level the combined dropper drops incoming excessive in-profile packets randomly with a constant probability when the token level in the leaky bucket stays in demotion region without incoming demoted in-profile packets. Considering the case where the token level cannot stay in demotion region without the prior demotion, we propose a token filling rate configuration method using traffic meters. By using the token filling rate configuration method, the modified REDP marker newly configures a token filling rate which is less than the negotiated rate determined by interdomain SLA and larger than the current input aggregate in-profile traffic rate. Then, with the newly configured token filling rate, the token level in the modified REDP marker can stay in demotion region pertinently fir the operation of the dropper to improve TCP fairness. We experiment with the modified REDP marker using ns2 simulator fur TCP sources at the general case where the token level cannot stay in demotion region without the prior demotion at the negotiated rate set as the bottleneck link bandwidth. The simulation results demonstrate that through the combined dropper with the newly configured token filling rate, the modified REDP marker also increases both aggregate in-profile throughput and link utilization in addition to TCP fairness improvement compared to the REDP marker.

• 한국측량학회지
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• 제34권4호
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• pp.373-382
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• 2016

In this study, an EKF (Extended Kalman Filter) based database reference navigation using both gravity gradient and terrain data was performed to complement the weakness of using only one type of geophysical DB (Database). Furthermore, a new algorithm which combines the EKF and profile matching was developed to improve the stability and accuracy of the positioning. On the basis of simulations, it was found that the overall navigation performance was improved by the combination of geophysical DBs except the two trajectories in which the divergence of TRN (Terrain Referenced Navigation) occurred. To solve the divergence problem, the profile matching algorithm using the terrain data is combined with the EKF. The results show that all trajectories generate the stable performance with positioning error ranges between 14m to 23m although not all trajectories positioning accuracy is improved. The average positioning error from the combined algorithm for all nine trajectories is about 18 m. For further study, a development of a switching geophysical DB or algorithm between the EKF and the profile matching to improve the navigation performance is suggested.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.896-900
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• 1996

New approach to determine the optimal design of automotive tire profile was introduced. In this study, optimal design technology was combined with a finite element method. Through tire profile optimization, tire profile was obtained and its profile improved high speed durability and maneuverability Static and dynamic behavior analysis of new concepted tire was compared with conventional tire profile. Optimal design methodology will provide much informations to improve various tire performances.

• 대한기계학회논문집A
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• 제39권2호
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• pp.169-177
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• 2015

내접형 기어펌프에 사용되는 지로터의 경우, 소결 공정기술의 발달로 복잡한 형상의 가공이 용이하며 내구성과 소형화의 장점이 있으나, 자동차의 연비효율 개선을 위한 유량증대 및 소음저감을 위한 연구가 요구되고 있다. 본 논문에서는 기존의 병진이동에 의한 지로터 치형의 형상조합 알고리즘이 가지는 형상 불연속성을 개선하기 위하여 회전이동 및 병진이동을 이용한 형상조합 알고리즘을 개발하였으며, 이를 토대로 개발된 설계 프로그램을 이용하여 3-타원이 조합된 경우와 타원 1-인벌루트-타원 2 이조합된 경우에 대해 치형형상을 도출하고, 형상에 따른 로터의 주요성능(유량, 유량맥동, 미끄럼률 및 압력각)을 계산하였다. 해석결과를 토대로 조합된 치형형상에 대한 최적설계를 수행하였으며, 기존 치형과의 성능 비교를 통하여 설계의 타당성을 검증하였다.

• 한국응용과학기술학회지
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• 제40권5호
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• pp.1104-1115
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• 2023

본 연구는 미세전류자극이 비만인의 체성분과 혈중지질성분의 변화에 미치는 효과를 규명하고, 복합운동의 효과와 비교함으로써 효과적인 체형 관리 방안으로서 미세전류자극의 유용성을 밝히고자 하였다. 체지방율 30% 이상인 여대생 30명을 통제집단, 복합운동집단, 미세전류자극집단으로 분류하였으며, 각 집단 별 4주간의 처치 전후 체중, 체지방율, 허리 둘레 등의 체성분 요인과 TG, TC, apolipoprotein 등의 혈중지질성분을 측정한 자료를 분석하여 다음과 같은 결과를 얻었다. 통제집단에서는 모든 측정 항목에서 통계적으로 유의한 차이가 나타나지 않은 반면 복합운동 집단에서는 허리둘레와 TC가 유의하게 감소한 것으로 나타났고, 미세전류자극 집단에서는 체중, 체지방율, 허리둘레, apolipoprotein 등이 유의하게 감소한 것으로 나타났다. 이러한 연구결과를 고려할 때 미세전류 자극은 비만인의 체성분과 혈중지질성분을 개선시켜 건강한 신체를 갖도록 하는데 효과적인 중재 방안으로 제안할 수 있다.