Monte Carlo Method and Quantile Regression for Uncertainty Analysis of Wind Power Forecasting Based on Chaos-LS-SVM

Xin Zhao,Chao Ge,Fangfang Ji,Yajuan Liu 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.11

In the paper, the chaos least squares support vector machine algorithm (Chaos-LS-SVM) is applied. To conduct uncertainty analysis of wind power forecasting, two forecasting algorithms of the probabilistic uncertainty analysis based on the Monte Carlo method and the quantile regression analysis based on Chaos-LS-SVM are discussed. The effectiveness and superiority of the two uncertainty analysis methods in the confidence level of 95%, 90%, and 85% are discussed by simulation analysis, and the confidence interval is given in the corresponding confidence level. The prediction interval coverage probability (PICP) and the prediction interval normalized average width (PINAW) of the two uncertainty methods are compared. In the time scale of 1h-ahead, 4h-ahead, and 6h-ahead, the probabilistic uncertainty analysis based on the Monte Carlo method is suitable. In the time scale of 24h-ahead, the quantile regression analysis based on Chaos-LS-SVM is superior.

Chaotic Dynamics of a Three-phase Clock-driven Oscillator with Dual Voltage Controllability

Ji Chao Zhou,송한정 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.61 No.8

In this work, we study a novel dual voltage controlled chaotic oscillator using a three-phase clock. The chaotic oscillator is based on two nonlinear functions which are needed for chaotic signal generation. The proposed chaotic circuit consists of non-overlapping clock driven three MOS (Metal Oxide Semiconductor) switches for S/H (sample and hold), a level shifter and two nonlinear functions for nonlinearity in the feedback. After optimizing of nonlinear functions for chaotic signal generation, the proposed circuit was simulated with SPICE (Simulation Program with Integrated Circuit Emphasis) program using a 0.6 um CMOS (complementary metal oxide semiconductor) process parameter. For various control voltages, its chaotic dynamics such as time waveform, bifurcation diagram and state transition diagram were analyzed. We confirmed that the circuit can generate discrete chaotic signals in specific control voltages. This circuit expected to be utilized for various chaos applications.

폐경기 중년여성의 운동 참여 효과 검증

우계초(Ji Chao Niu),장명재(Myoung Jei Chang),이신언(Shin Eon Lee),최희연(Hee Yeon Choi) 한국사회체육학회 2012 한국사회체육학회지 Vol.0 No.49

Physical activity is known to reduce risk of early death through reduction of risk of metabolic syndrome, prevention of weight gain, reduction of abdominal obesity, and increment of bone density. Despite the presence of some physical activity guidelines, a lot of people have been conduct physical activity by their own standards. In the present study, the effects of physical activity that based on arbitrary criteria on the obesity and osteoporosis were investigated. 64 volunteers, who aged over 40 and under 50, were participated. And they were divided into four subgroups(menstruation without exercise, menstruation with exercise, postmenopause without exercise, postmenopause with exercise) to determine the participation of physical activity and menstrual status. In the present results, statistically significant differences occurred in %Fat, abdominal fat ratio, visceral fat area, despite no statistical differences in body mass index in each groups. % Fat, abdominal fat ratio, visceral fat area was increased significantly by menopause, however, physical activity showed the opposite effects. In the blood analysis results were not statistically significant difference occurred. Regression analysis results on visceral fat area showd that age, body mass index, w·aist circumference, triglyceride levels have been identified as a statistically significant, and menstruation showd that T-score and Z-score levels have been identified as a statistically significant. Base on the results of present study, it is suggested that physical activity that conducted by the arbitrary criteria in women after menopause showed positive effects on abdominal fat, and osteoporosis, however for the more obvious effects, increasing calorie consumption and frequency of participation is desirable.

급속 충전에서 탱크 내부의 수소 온도 변화에 관한 이론 연구

이길초(JI-CHAO LI),이길강(JI-QIANG LI),허항(HENG XU),최병철(BYUNG CHUL CHOI),권정태(JEONG-TAE KWON) 한국수소및신에너지학회 2023 한국수소 및 신에너지학회논문집 Vol.34 No.6

The fast filling process of high-pressure hydrogen has an important impact on the filling efficiency and safety. In this paper, a specific study is carried out on the thermophysical phenomena during the fast filling process. Starting from the gas state equation of hydrogen, the change law of the hydrogen storage temperature is obtained, and then the temperature rise prediction is constructed. The model can clarify the relationship between the filling parameters and the temperature rise during the fast filling process, thereby revealing the flow and heat transfer laws of the fast charging process. To improve the theoretical research basis for the evaluation of vehicle-mounted hydrogen fast charging capacity, temperature prediction and optimization of hydrogenation methods.

YAP/TAZ-Mediated Upregulation of GAB2 Leads to Increased Sensitivity to Growth Factor–Induced Activation of the PI3K Pathway

Wang, Chao,Gu, Chao,Jeong, Kang Jin,Zhang, Dong,Guo, Wei,Lu, Yiling,Ju, Zhenlin,Panupinthu, Nattapon,Yang, Ji Yeon,Gagea, Mihai (Mike),Ng, Patrick Kwok Shing,Zhang, Fan,Mills, Gordon B. American Association for Cancer Research 2017 Cancer Research Vol.77 No.7

<P>Interactions between HIPPO, YAP/TAZ, and the PI3K/AKT pathway may be therapeutically targetable, providing new approaches to treating endometrial cancers and other cancers where the HIPPO pathway is a core oncogenic driver.</P><P>The transcription regulators YAP and TAZ function as effectors of the HIPPO signaling cascade, critical for organismal development, cell growth, and cellular reprogramming, and YAP/TAZ is commonly misregulated in human cancers. The precise mechanism by which aberrant YAP/TAZ promotes tumor growth remains unclear. The HIPPO tumor suppressor pathway phosphorylates YAP and TAZ, resulting in cytosolic sequestration with subsequent degradation. Here, we report that the PI3K/AKT pathway, which is critically involved in the pathophysiology of endometrial cancer, interacts with the HIPPO pathway at multiple levels. Strikingly, coordinate knockdown of YAP and TAZ, mimicking activation of the HIPPO pathway, markedly decreased both constitutive and growth factor–induced PI3K pathway activation by decreasing levels of the GAB2 linker molecule in endometrial cancer lines. Furthermore, targeting YAP/TAZ decreased endometrial cancer tumor growth <I>in vivo</I>. In addition, YAP and TAZ total and phosphoprotein levels correlated with clinical characteristics and outcomes in endometrial cancer. Thus, YAP and TAZ, which are inhibited by the HIPPO tumor suppressor pathway, modify PI3K/AKT pathway signaling in endometrial cancer. The cross-talk between these key pathways identifies potential new biomarkers and therapeutic targets in endometrial cancer. <I>Cancer Res; 77(7); 1637–48. ©2017 AACR</I>.</P>

가정용 소형 제습로터의 성능에 대한 실험적 연구

한기초(Han, Ji-Chao),김내현(Kim, Nae-Hyun) 한국산학기술학회 2015 한국산학기술학회논문지 Vol.16 No.4

여름철이 고온 다습한 우리나라에서는 잠열부하가 크기 때문에 에어컨만을 사용하면 냉방에너지를 많이 사용하게 된다. 이 때에 제습기를 동시에 사용하면 냉방 중 큰 비중을 차지하는 잠열부하를 줄일 수 있어 실내 공기질도 개선하고 냉방에너지도 절약할 수 있다. 본 연구에서는 가정용 제습기에 사용되는 무기섬유 기질에 메탈 실리케이트가 함침된 소형 제습 로터에 대하여 항온항습실에서 로터 회전속도, 재생 공기온도, 실내 공기온도, 실내 상대습도, 제습부 전방풍속을 변화 시키며 제습 성능을 측정하였다. 제습 로터는 최적 회전수 (1.0rpm)가 존재하며 최적치를 초과하면 불완전 재생 등으로 제습 량이 급격히 감소한다. 재생온도가 높아질수록 재생에는 유리하나 제습-재생과정의 열적인 편차가 급격히 증가하여 제습량 이 감소한다. 따라서 최적 재생온도가 존재하는데 본 연구의 경우는 100oC로 나타났다. 상대습도의 증가에 따라 제습량도 증가한다. 이는 제습제의 제습능력이 상대습도에 의존하는 때문이다. 실내 공기온도의 증가에 따라 제습량도 증가한다. 이는 제습측 온도가 높을 때 재생측 공기와의 열적 편차가 감소하여 제습부의 상당량이 제습에만 사용될 수 있기 때문이다. 전방 풍속의 증가에 따라 제습량도 증가한다. 이는 전방풍속의 증가에 따라 열 및 물질전달계수가 증가하기 때문이다. In Korea, summer is hot and humid, and air-conditioners consume too much electricity due to large amount of latent heat. Simultaneous usage of dehumidifier may reduce the latent heat and save the electricity. In this study, dehumidification performance was measured in a constant temperature and humidity chamber for a small-sized dehumdification rotor made of inorganic fiber impregnated with metallic silicate. Variables were rotor speed, room temperature, regeneration temperature, room relative humidity and frontal velocity to the rotor. Results showed that there existed optimum rotor speed (1.0 rpm), and optimum regeneration temperature (100oC). Above the optimum rotor speed, incomplete regeneration is responsible for reduced dehumidification. Above the optimum regeneration temperature, increased temperature difference between regeneration and dehumidification process is responsible for reduced dehumidification. The amount of dehumidification also increases with the increase of relative humidity, dehumidification temperature and flow velocity into the rotor.

Research on Fracture of Aluminum Foil in Microscale Laser Peen Forming

Chao Zheng,Sheng Sun,Jing Liu,Zhong Ji 한국소성가공학회 2010 기타자료 Vol.2010 No.6

A novel numerical method for dynamic fracture in microscale laser peen forming (μLPF) of aluminum foils was presented and the role of the die diameter on fracture behavior at the ultra high strain rate was investigated via both experimental and numerical methods. μLPF is a process in which the plastic deformation is generated through laserinduced shock wave and compressive residual stresses can be imparted to improve the fatigue life of micro parts. During μLPF, the pressure exerted on the target is higher than 1 GPa and the strain rate is greater than 10? s<SUP>-1</SUP>, so the mechanical behavior of materials in this dynamic process is very different from that under static or quasi-static conditions. In the present study, the finite element method with grain and grain boundary elements was used to analyze the μLPF process of aluminum foils with a thickness of 60 μm. The onset and propagation of crack were simulated in this way that the specified nodes were tied together until the equivalent plastic strain exceeded a certain value. Under a given value of plastic strain, the influence of die diameters of 0.6, 1.0, and 1.6 mm on the fracture mode of the material was predicted. A series of experiments were carried out to verify the numerical model. The geometrical morphologies of fracture regions were observed via optical microscope and scan electron microscope. In results from both experiments and simulations, the size of the die diameter affects the location of the fracture: (I) Fracture appeared at the entrance of the die for die diameters of 0.6 and 1.0 mm. (II) Fracture occurred near the centre of the formed dome for 1.6 mm die diameter. The generation mechanism of two fracture modes was explained. This work provides a preliminary insight into the fracture behavior of materials under the ultra high strain rate and lays the ground work for more in-depth simulations in the future study.

MACC1 Expression Correlates with PFKFB2 and Survival in Hepatocellular Carcinoma

Ji, Dong,Lu, Zhong-Tang,Li, Yao-Qing,Liang, Zhe-Yong,Zhang, Peng-Fei,Li, Chao,Zhang, Jun-Li,Zheng, Xin,Yao, Ying-Min Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.2

Objective: To validate the relationship between MACC1 and 6-phosphofructo-2-kinase/fructose 2, 6 bisphosphatase (PFKFB2) expression as well as its clinicopathological features and prognostic significance in hepatocellular carcinoma. Methods: By using immunohistochemistry, we investigated the MACC1 and PFKFB2 protein expression in 60 pairs of hepatocellular carcinoma and corresponding non-tumor tissues. Using the Mann-Whitney U test, the Chi-square test, Kaplan-Meier survival analysis, Cox proportional hazard regression analysis and Spearman analysis, we studied the relationship between MACC1 and PFKFB2 protein expression and postoperative overall survival (OS) of the HCC patients. Results: MACC1 and PFKFB2 positive staining rates were significantly higher in hepatocellular carcinoma than in the corresponding nontumor tissues (P=0.012 and 0.04, respectively). The clinicopathological features evaluation revealed that positive expression of MACC1 was associated with a high Edmondson classification (P=0.007) and advanced TNM stage (P=0.027). Similar findings were evident for PFKFB2 expression (P=0.002 and P=0.027). MACC1 and PFKFB2 positive expression was associated with a lower OS rate (P=0.004 and 0.03, respectively). Kaplan-Meier survival and Cox proportional hazard regression analyses revealed MACC1 positive expression to be a prognostic factor for postoperative OS, but PFKFB was not. Conclusion: Highly expressed MACC1 and PFKFB2 protein were associated with TNM stage, Edmondson-Steier classification and overall survival. MACC1 may affect tumor metabolism partly through expression and phophorylation of PFKFB2.

Solutions of several open problems

Chao-Ping Chen,Ji-En Deng 장전수학회 2012 Advanced Studies in Contemporary Mathematics Vol.22 No.4

The main object of this paper is to solve several open problems proposed by Zhang and X_u, Bencze, and Simic. (i) We prove that for x > 0, [수식].

Development of Control Strategy and Energy Management for Plug-in HEV

Chao Ma,Jian Ji(지건),Hyunsoo Kim(김현수) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5

Plug-in Hybrid Electric Vehicle (PHEV) is considered as the next design objective of hybrid electric vehicle (HEV). It combines the advantages of electric vehicle (EV) and HEV. PHEV has full electric drive mode which can be applied in relative short distance and HEV mode which can be used for long distance. In this paper, the powertrain model of the PHEV is obtained. Based on the analysis of the powertrain model, the control strategy and energy management strategy of PHEV are developed. The PHEV simulator is constructed MATLAB/Simulink. Using the powertrain model and the control strategies, simulations are performed and the simulation results are analyzed. Finally, the plug-in Prius simulator is validated by using the PSAT. It is expected that the PHEV performance can be used for the designers to develop a PHEV.