Wet dual clutch launching adaptive control considering service time

Ke Ma,Dongye Sun,Guanlong Sun,Dongyang Wang 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.6

In this study, an adaptive control strategy named, “front-end optimization + back-end compensation,” is proposed to address the wet dual-clutch transmission start-up problem, while considering the effect of service time on the degradation of friction characteristics. First, the effect of service time on friction characteristics is investigated experimentally. Subsequently, the friction coefficient is estimated using a dual extended Kalman filter, and the optimal motion and control trajectory for the launching process are obtained using the pseudospectral method. Finally, a back-end compensator is designed. The effectiveness of the strategy is verified using the MATLAB/Simulink platform and a vehicle test. The results show that compared with the minimum principle method, the pseudo-spectral method shows less jerk and friction loss with a comparable launching time. The control law is adjusted based on the estimated friction coefficient, which ensures a good start-up. Moreover, the back-end compensator can track the reference trajectory well with parameter perturbation.

Evaluation and Design Tools for the Reliability of Wind Power Converter System

Ke Ma,Dao Zhou,Frede Blaabjerg 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.5

As a key part in the wind turbine system, the power electronic converter is proven to have high failure rates. At the same time, the failure of the wind power converter is becoming more unacceptable because of the quick growth in capacity, remote locations to reach, and strong impact to the power grid. As a result, the correct assessment of reliable performance for power electronics is a crucial and emerging need; the assessment is essential for design improvement, as well as for the extension of converter lifetime and reduction of energy cost. Unfortunately, there still exists a lack of suitable physic-of-failure based evaluation tools for a reliability assessment in power electronics. In this paper, an advanced tool structure which can acquire various reliability metrics of wind power converter is proposed. The tool is based on failure mechanisms in critical components of the system and mission profiles in wind turbines. Potential methodologies, challenges, and technology trends involved in this tool structure are also discussed. Finally, a simplified version of the tool is demonstrated on a wind power converter based on Double Fed Induction Generator system. With the proposed tool structure, more detailed information of reliability performances in a wind power converter can be obtained before the converter can actually fail in the field and many potential research topics can also be initiated.

Money Network

Ke Lin Ma 한국콘텐츠학회 2011 ICCC International Digital Design Invitation Exhib Vol.2011 No.5

Evaluation and Design Tools for the Reliability of Wind Power Converter System

Ma, Ke,Zhou, Dao,Blaabjerg, Frede The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.5

As a key part in the wind turbine system, the power electronic converter is proven to have high failure rates. At the same time, the failure of the wind power converter is becoming more unacceptable because of the quick growth in capacity, remote locations to reach, and strong impact to the power grid. As a result, the correct assessment of reliable performance for power electronics is a crucial and emerging need; the assessment is essential for design improvement, as well as for the extension of converter lifetime and reduction of energy cost. Unfortunately, there still exists a lack of suitable physic-of-failure based evaluation tools for a reliability assessment in power electronics. In this paper, an advanced tool structure which can acquire various reliability metrics of wind power converter is proposed. The tool is based on failure mechanisms in critical components of the system and mission profiles in wind turbines. Potential methodologies, challenges, and technology trends involved in this tool structure are also discussed. Finally, a simplified version of the tool is demonstrated on a wind power converter based on Double Fed Induction Generator system. With the proposed tool structure, more detailed information of reliability performances in a wind power converter can be obtained before the converter can actually fail in the field and many potential research topics can also be initiated.

High-j Proton h11/2 and g7/2 Intruder Bands in 113In

Ma Ke Yan,Lu Jing Bin,Ma Ying Jun,Li Jian,Yang Dong,Sun Wu Ji,Wang Hao,Pan Hao Nan,Wang Jia Qi,Yang Qing Yu,Zhang Da Ming,Zhu Li Hua,Wu Xiao Guang,Zheng Yun,Li Cong Bo 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.76 No.12

Excited states of 113In have been populated through the heavy-ion fusion evaporation reaction 110Pd(7Li, 4n)113In. A new band with the configuration of a proton d5/2 orbital is identified. Two ΔI = 2 intruder bands, built on the πh11/2 and the πg7/2 orbitals, have been extended to spins (63/2-)ħ and (55/2+)ħ, respectively. The negative-parity πh11/2 intruder band shows a smooth increase in aligned spin, which is attributed to a strong proton-neutron interaction. The properties of the positive-parity πg7/2 band are discussed based on tilted axis cranking model calculations, and the features of the antimagnetic rotation for this band are shown after backbend. Furthermore, the contributions of the two-shears-like mechanism, the neutron (gd)ν shell and the core rotation are investigated for the positive-parity πg7/2 band.

The Microbial Mechanisms for Intermittent Drainages on Methane Cycle in Rice Field Soil

Ke Ma,Yahai Lu,Ralf Conrad,Chenwei Ai 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

Robust Control for Spacecraft Rendezvous with Disturbances and Input Saturation

Yi-Ke Ma,Haibo Ji 제어·로봇·시스템학회 2015 International Journal of Control, Automation, and Vol.13 No.2

This paper deals with the stabilization problem of spacecraft rendezvous in the presence of disturbances and input saturation. A dead zone operator based model is used to describe the saturation phenomenon. By using Lyapunov method, two groups of control laws are obtained, which ensure the input-to-state stability and the input-to-state practical stability of the closed-loop systems respect to disturbance acceleration, respectively. Simulation results are provided to illustrate the effectiveness of the proposed approaches.

한국 문인들의 陳與義시가의 수용 양상연구

馬金科(Ma Jin Ke),譚紅梅(Tan Hong Mei) 동악어문학회 2010 동악어문학 Vol.55 No.-

陳與義는 江西詩派의 3대 대표 시인 중 한 사람으로서, 그의 시는 강서시파가 고려와 조선에 수용되는데 일정한 영향을 미쳤다. 한국 고대 시인들이 진여의의 시를 수용하는 양상은 그 특수한 언어 환경으로 말미암아 중국과는 다른 면모를 보일 수밖에 없었다. 우선 수용 과정이 달랐다. 한 예로 그의 詩句를 그대로 인용하여 시를 짓는 경향을 보인다. 실제로 한국 시학은 진여의 시가의 수용과정에서 그의 두시 시학에 대한 역사적 답습을 매우 중시하였다. 아울러 그가 韓愈, 黃庭堅, 陳師道및 기타 시인들을 따라 배운 점에 유의하여 시법의 측면에서 적지 않은 관심을 보였다. 또한 조선조 문인들은 그의 시창작에 대하여 다각적인 평가를 하는데 역점을 두었다. 이는 조선조 문인들이 杜詩의 전승 역사를 매우 중시한 결과로 판단된다. 그와 동시에 한유 등의 영향을 놓치지 않고 추적하기도 하였다. 이런 점은 중국 시학 연구 분야에서도 충분한 관심을 보이지 않은 실정이어서 조선조 문인들의 중국 시인들에 대한 관심을 폭을 이해케 한다. 마지막으로 시기에 따라 진여의에 대한 평가가 엇갈리고 개별 시편에 대해서는 판이한 결론이 내려진 점도 흥미롭다. Jin Yeo-Oui(陳與義) was one of 3 representative poets in Gang-Seo Poem circle(江西詩派), and his poetry influenced on his poem circle's transmission and acceptance in Goryeo and Joseon Dynasties in certain degree. The appearance that Korean ancient poets accepted his poetry was different from Chinese' acceptance way causing from Korea's special language environment, First, both nation's acceptance ways was different. For instance, Korean literary tended to write their poets by directly citing his verses. In fact, Korean poetics considered Jin Yeo-Oui's historical following Tu Fu(杜甫)'s poetics in his poetry as very important one during their course accepting his poetry. Besides, anxious about his learning from other poets like Han Yu(韓愈), Hwang Jeong-Gyeon(黃庭堅), Jin Sha-Do(陳師道) and others, they had much interest in his poetry in aspect of prosody. Also, Joseon literary people focused on multilateral evaluation on his poet creation. This is judged as the result from the fact that they considered Tu Fu(杜甫)'s poetry's transmission history very importantly. At the same time, they tracked down some influences of other poets like Han Yu. Such features were shown because there wasn't enough interest in poetics study in China, so it is understood that Joseon literary had a broad interest of Chinese poets. Finally, it is also interested that the evaluations on Jin Yeo-Oui's works were very opposite varying to ages, and his individual poet got absolutely different assessments.

김봉룡과 강천리 작품을 중심으로 본 한 중 나전칠기 비교 및 4차산업 기술 융합을 통한 발전방안 연구

마가상(Ma, Ke Xiang),이성원(Lee, Sung Won) 한국전시산업융합연구원 2020 한국과학예술융합학회 Vol.38 No.3

나전칠기는 한 · 중 · 일을 대표하는 전통 공예기법이다. 독특하고 아름다운 예술 양식인 나전칠기는 미적가치와 전통공예로서의 실용성을 두루 갖추고 있다. 본 연구의 목적은 한국과 중국 양국을 대표하는 장인인 ‘강천리(江千里)’와 ‘김봉룡(金奉龍)’을 비교 분석함으로써 두 나라가 공유하는 나전칠기 예술의 보편적 특성을 논의함과 동시에 각국의 나전칠기 양식이 가진 특수성을 비교하여 나전칠기 공예의 대중화와 현대화 방안을 모색하는 데 있다. 따라서 본 논문은 작품 분석과 문헌연구방법을 통하여 두 나라의 나전칠기에 대한 예술사적 흐름을 고찰하고 두 사람의 작품중 대표성을 띠는 작품 범위에 한정하여 비교 · 대조, 분석을 이행하였다. 연구결과 및 내용은 다음과 같다. 첫째, 두 사람의 시대적 배경과 작품 특징 및 예술 양식은 작품 모티브, 작품 주제, 기법 등에서 뚜렷한 차이를 보임이 나타났다. 둘째, 4차산업 기술에 해당하는 AI와 3D프린팅 기능은 전통이나 고전으로만 남아있는 나전칠기 공예를 새롭게 해석할 수 있는 실마리가 될 수 있다는 점도 확인하였다. 이러한 연구결과를 바탕으로 동아시아가 공유하는 전통 예술인 나전칠기의 우수성을 다시 한번 되새기고, 나전칠기 예술의 계승과 발전에 이바지하기를 기대한다. Najeonchigi is a traditional craft technique that represents Korea, China, and Japan. A unique and beautiful style of art, Najeon Chilgi has a wide range of aesthetic values and practicality as a traditional craft. The purpose of this study is to discuss the universal characteristics of Najeon Chilgi art shared by the two countries by comparing and analyzing "Gang cheon-ri" and "Kim Bong-ryong," the craftsmen representing both Korea and China, while at the same time comparing the specialities of Najeon Chilgi styles of each country to find ways to popularize and modernize Najeon Chilgi crafts. Therefore, through the analysis of works and the method of literature research, this paper considered the flow of art history about the najeonchigi of the two countries and carried out the comparison, contrast and analysis limited to the range of works that bear representativeness among the two works. The results and contents of the study are as follows. First, the period background and work characteristics and art styles of the two showed distinct differences in work motifs, work themes and techniques. Second, it was also confirmed that the AI and 3D printing functions, which correspond to the fourth industrial technology, could serve as a clue to a new interpretation of the lacquerware, which remains traditional or classical. Based on these findings, we hope to reflect on the excellence of Najeon Chilgi, a traditional art shared by East Asia, and to contribute to the succession and development of Najeon Chilgi art.

Simulated Ion Velocity Distribution and Its Incoherent Scattering Spectrum in the High-latitude Ionosphere

Bao-Ke Ma,Li-Xin Guo,Hong-Tao Su,Bei-Chen Zhang 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.63 No.8

If the relatively larger convection electric field and small the collision frequency between ions andneutrals in the high-latitude ionosphere are considered, the integral solution of the non-Maxwellianion velocity distribution function for the relaxation collision model is simplified, and a torus distributionfunction of the ion velocity is obtained. Also, the feature of the torus velocity distributionfunction is analyzed and simulated with different parameters in high-latitude ionosphere. Furthermore,by using the electromagnetic radiation theory of Sheffield and taking into account the iontemperature anisotropy and its variation with the electric field, we simulate the incoherent scatteringspectrum of ions in different directions. The research shows that the ionospheric convectionelectric field, the ion-neutral collision frequency and the ion anisotropic temperature distributionall have an effect on the incoherent scattering spectrum.