선물 유휴 공유를 위한 새로운 서비스 디자인 : 앱과의 상호 작용에 초전

Tang Xiaoxue,Guo Haoyue,Pan Young Hwan 한국서비스디자인학회 2019 한국서비스디자인학회 학술대회자료집 Vol.2019 No.2

Dynamic control stability analysis of pipeline intelligent plugging robot in its deceleration and precise positioning

Yang Tang,Jie Wu,Xiang Liu,Xin Yang,Yuan Wang,Haoyu Xiong 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.9

In order to realize the precise positioning of the tools in the pipeline repair operation, solve the problems of the traditional throttle speed control, such as slow response, long deceleration distance and so on, this paper explores a deceleration process of a pipeline intelligent plugging robot (PIPR) that relies on the friction between slips and the pipe, and establishes its dynamic model based on fuzzy PID force servo control. The influence of PIPR initial velocity, expected deceleration distance, accumulator setting on the response time, positioning accuracy, overshoot and stability during deceleration is analyzed, and the results show that: as the initial velocity increases, the time for slips to contact the pipe decreases, the overshoot of the centroid acceleration gradually increases, the maximum overshoot is -3.4 m/s 2 , the control time of the deceleration process is within 30 s, the positioning accuracy is within 5 %; the expected deceleration distance has a greater impact on the positioning accuracy of the system than the initial velocity; and the accumulator setting has little effect on the positioning accuracy and stability of the system. These studies provide guidance for the design of pipeline robot speed control and positioning system.

Sampling for Remote Estimation of an Ornstein-Uhlenbeck Process through Channel with Unknown Delay Statistics

Chen, Yuchao,Tang, Haoyue,Wang, Jintao,Yang, Pengkun,Tassiulas, Leandros 한국통신학회 2023 Journal of communications and networks Vol.25 No.5

In this paper, we consider sampling an Ornstein-Uhlenbeck (OU) process through a channel for remote estimation. The goal is to minimize the mean square error (MSE) at the estimator under a sampling frequency constraint when the channel delay statistics is unknown. Sampling for MSE minimization is reformulated into an optimal stopping problem. By revisiting the threshold structure of the optimal stopping policy when the delay statistics is known, we propose an online sampling algorithm to learn the optimum threshold using stochastic approximation algorithm and the virtual queue method. We prove that with probability 1, the MSE of the proposed online algorithm converges to the minimum MSE that is achieved when the channel delay statistics is known. The cumulative MSE gap of our proposed algorithm compared with the minimum MSE up to the $(k+1)$-th sample grows with rate at most $\mathcal{O}(\ln k)$. Our proposed online algorithm can satisfy the sampling frequency constraint theoretically. Finally, simulation results are provided to demonstrate the performance of the proposed algorithm.

The Positive Association between Subclinical Hypothyroidism and Newly-Diagnosed Hypertension Is More Explicit in Female Individuals Younger than 65

Xichang Wang,Haoyu Wang,Li Yan,Lihui Yang,Yuanming Xue,Jing Yang,Yongli Yao,Xulei Tang,Nanwei Tong,Guixia Wang,Jinan Zhang,Youmin Wang,Jianming Ba,Bing Chen,Jianling Du,Lanjie He,Xiaoyang Lai,Yanbo Li 대한내분비학회 2021 Endocrinology and metabolism Vol.36 No.4

Background: Subclinical hypothyroidism (SCH) is the most common thyroid dysfunction, and its relationship with blood pressure(BP) has been controversial. The aim of the study was to analyze the association between SCH and newly-diagnosed hypertension. Methods: Based on data from the Thyroid disease, Iodine nutrition and Diabetes Epidemiology (TIDE) study, 49,433 euthyroid individuals and 7,719 SCH patients aged ≥18 years were enrolled. Patients with a history of hypertension or thyroid disease were excluded. SCH was determined by manufacturer reference range. Overall hypertension and stage 1 and 2 hypertension were diagnosedaccording to the guidelines issued by the American College of Cardiology/American Heart Association in 2017. Results: The prevalence of overall hypertension (48.7%), including stage 1 (28.9%) and 2 (19.8%) hypertension, increased significantly in SCH patients compared with euthyroid subjects. With elevated serum thyroid stimulating hormone (TSH) level, the hypertension prevalence also increased significantly from the euthyroid to different SCH subgroups, which was more profound in femalesor subjects aged <65 years. The age- and sex-specific regression analysis further demonstrated the same trends in the general population and in the 1:1 propensity matched population. Similarly, several BP components (i.e., systolic, diastolic, and mean arterial BP)were positively associated with TSH elevation, and regression analysis also confirmed that all BP components were closely relatedwith SCH in female subjects aged <65 years. Conclusion: The prevalence of hypertension increases for patients with SCH. SCH tends to be associated with hypertension and BPcomponents in females younger than 65 years.

Modelling of effective irradiation swelling for inert matrix fuels

Zhang, Jing,Wang, Haoyu,Wei, Hongyang,Zhang, Jingyu,Tang, Changbing,Lu, Chuan,Huang, Chunlan,Ding, Shurong,Li, Yuanming Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.8

The results of effective irradiation swelling in a wide range of burnup levels are numerically obtained for an inert matrix fuel, which are verified with DART model. The fission gas swelling of fuel particles is calculated with a mechanistic model, which depends on the external hydrostatic pressure. Additionally, irradiation and thermal creep effects are included in the inert matrix. The effects of matrix creep strains, external hydrostatic pressure and temperature on the effective irradiation swelling are investigated. The research results indicate that (1) the above effects are coupled with each other; (2) the matrix creep effects at high temperatures should be involved; and (3) ranged from 0 to 300 MPa, a remarkable dependence of external hydrostatic pressure can be found. Furthermore, an explicit multi-variable mathematic model is established for the effective irradiation swelling, as a function of particle volume fraction, temperature, external hydrostatic pressure and fuel particle fission density, which can well reproduce the finite element results. The mathematic model for the current volume fraction of fuel particles can help establish other effective performance models.

Research on the Calculation of Rotor’s Convective Heat Transfer Coefficient of High-Speed Drive Motor for EVs Based on Multiple Scenarios

Wu Zhigang,Li Weili,Tang Haoyue,Luo Shifan,Zhang Liangliang 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.6

In order to adapt the development demand of electric vehicle (EV) drive motor with high power density, high-speed motor is an inevitable trend. There have been numerous studies on the optimisation of cooling structures and losses in high-speed motor, but little has been said about the mechanism of heat transfer problems. Especially in the context of diverse driving scenarios and high-speed drive for EVs, it is crucial to study the differences in heat transfer mechanisms between high-speed motors and normal-speed motors. The research work is based on a principle prototype with a maximum speed of 50 kW-30,000 rpm. A dynamic calculation method is proposed for the rotor’s convective heat transfer coefficient (CHTC) over a wide speed range and multiple scenarios. This method has the advantages of simplicity and high efficiency in calculating the CHTC of rotor, and avoids the complex preprocessing and difficult convergence problems of the fluid–solid coupling calculation. Finally, the accuracy of the calculation results is verified by the temperature rise test of the high-speed motor.

Health diagnosis of permanent magnets under different cooling system effectiveness in high‑speed permanent magnet motors for electric vehicles

Meiwei Zhang,Weili Li,Wanlu Xie,Haoyue Tang,Zhigang Wu 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.3

The power density of a high-speed permanent magnet (PM) motor is high, and the heat dissipation of its rotor is poor due to limited installation space. Th0000000000000000000us, the temperature of the permanent magnets is high. Once the cooling system of a motor becomes ineffective and the rotor temperature exceeds the limit temperature of the PM material, a demagnetization fault of the PM occur, which seriously affects the performance of the PM motor. To ensure the safe and reliable operation of PM motors, a method to diagnose the PM health is presented in this paper. The demagnetization ratio of the PM can be diagnosed quantitatively by its temperature. In this paper, the relationship between the temperature and the demagnetization ratio of a PM is obtained through thermal demagnetization tests, and the threshold temperature of demagnetization is given. Then, the health of a PM under different effectiveness of the cooling system in a high-speed PM motor is researched. Finally, the calculation results are verified by temperature tests of a high-speed PM motor.

Conceptual design of a dual drum-controlled space molten salt reactor (D² -SMSR): Neutron physics and thermal hydraulics

Yongnian Song,Nailiang Zhuang,Hangbin Zhao,Chen Ji,Haoyue Deng,Xiaobin Tang Korean Nuclear Society 2023 Nuclear Engineering and Technology Vol.55 No.6

Space nuclear reactors are becoming popular in deep space exploration owing to their advantages of high-power density and stability. Following the fourth-generation nuclear reactor technology, a conceptual design of the dual drum-controlled space molten salt reactor (D²-SMSR) is proposed. The reactor concept uses molten salt as fuel and heat pipes for cooling. A new reactivity control strategy that combines control drums and safety drums was adopted. Critical physical characteristics such as neutron energy spectrum, neutron flux distribution, power distribution and burnup depth were calculated. Flow and heat transfer characteristics such as natural convection, velocity and temperature distribution of the D²-SMSR under low gravity conditions were analyzed. The reactivity control effect of the dual-drums strategy was evaluated. Results showed that the D²-SMSR with a fast spectrum could operate for 10 years at the full power of 40 kWth. The D²-SMSR has a high heat transfer coefficient between molten salt and heat pipe, which means that the core has a good heat-exchange performance. The new reactivity control strategy can achieve shutdown with one safety drum or three control drums, ensuring high-security standards. The present study can provide a theoretical reference for the design of space nuclear reactors.