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Yifei Zhang,Ming Zhu,Tian Chen,Zewei Zheng 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.1
This paper investigates the distributed formation control problem of multiple stratospheric airships in three-dimensional space with several practical problems, such as relative state constraints, input delay, input saturation and disturbances. An adaptive mixed self-/event-triggered formation control scheme is proposed by combining backstepping control, an adaptation technique and a mixed self-/event-triggered control mechanism. First, a novel relative-error-constraint virtual control law is designed based on the barrier Lyapunov function, which is processed into the desired velocity and angular velocity as the input of the next-step designed controller. Then, an adaptive controller is designed based on a designed adaptive law that is utilized to eliminate the influence of external disturbances, input saturation and input delay. In addition, a mixed self-/event-triggered mechanism is designed in the whole system, involving a self-triggered mechanism in the virtual control law and an event-triggered mechanism in the adaptive controller. All signals in the closed-loop system are proven to be semiglobal, uniform and ultimately bounded, and Zeno behavior is proven to be excluded. Finally, the effectiveness of the proposed method is verified through simulations.
Yifei Wang,Kaiyu Sun,Jingxian Shen,Bin Li,Ming Kuang,Qinghua Cao,Sui Peng 대한암학회 2019 Cancer Research and Treatment Vol.51 No.4
Purpose Hepatocellular carcinoma (HCC) is an aggressive disease with high recurrence rate. However, current staging systems were lack of predictive capacity for HCC recurrence. We aimed to develop prognostic nomograms based on inflammation-related markers for HCC patients underwent hepatectomy. Materials and Methods We recruited 889 surgically treated patients from two medical centers. Independent prognostic factors were identified by cox regression analyses. Nomograms for recurrence-free survival (RFS) and overall survival (OS) were established and validated internally and externally. The performance, discrimination, and calibration of nomograms were assessed and compared with existed staging systems. Results Neutrophil to lymphocyte ratio (NLR) and gamma-glutamyl transpeptidase to platelet ratio (GPR) were the two inflammation-related factor that independently correlated with survival. NLR, GPR, international normalized ratio (INR), microvascular invasion, satellite lesions, tumor number, tumor diameter, and macrovascular invasion were used to construct nomogram for RFS while GPR, total bilirubin, INR, -fetoprotein, microvascular invasion, satellite lesions, tumor diameter, and macrovascular invasion were for OS. In the training cohort, the C-index of nomogram was 0.701 (95% confidence interval [CI], 0.669 to 0.732) for RFS and 0.761 (95% CI, 0.728 to 0.795) for OS. These results received both internal and external validation with C-index of 0.701 (95% CI, 0.647 to 0.755) and 0.707 (95% CI, 0.657 to 0.756) for RFS, and 0.706 (95% CI, 0.640 to 0.772) and 0.708 (95%CI, 0.646 to 0.771) for OS, respectively. The nomograms showed superior accuracy to conventional staging systems (p < 0.001). Conclusion The nomograms based on inflammation-related markers are of high efficacy in predicting survival of HCC patients after hepatectomy, which will be valuable in guiding postoperative interventions and follow-ups.
Electrochemical Polishing of Additively Manufactured Ti–6Al–4V Alloy
Yifei Zhang,Jianzhong Li,Shuanghang Che,Yanwen Tian 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.6
In this present paper, the electropolishing behavior of Ti–6Al–4V alloy fabricated by additive manufacturing in chloridecontainingethylene glycol electrolyte was surveyed. The impacts of chloride ion on surface quality and oxide film ofTi–6Al–4V were analyzed in dependence on the surface topography, roughness, weight loss ratio and compositions. Thevisual and microscopic results revealed that the optimally electropolished surface was attained in a 0.4 mol L−1 chlorideelectrolyte with a decreased surface roughness of 75.04% and a weight loss rate of 4.93%. For lower (CCl−1 ≤ 0.3 mol L−1)or higher concentrations (CCl−1 ≥ 0.5 mol L−1), a smooth and flat surface was not observed due to insufficient reactions orexcessive anodic dissolution. During the electropolishing, the titanium oxides nucleated and corresponding surface tensionincreased, resulting in the formation of a stable TiO2film on the surface of the Ti–6Al–4V alloy, increasing the corrosionresistance of the specimen.
YiFei Zhang,Young Je Sim 대한스포츠물리치료학회 2022 정형스포츠물리치료학회지 Vol.18 No.1
Purpose: This study is to compare and analyze changes in body composition and changes in muscle tone of the biceps brachii, triceps brachii, quadriceps and hamstrings at rest after 10 weeks of weight training to improve muscle hypertrophy and muscular endurance. Methods: Twenty participants who were randomly assigned to group that performed weight training for muscle hypertrophy and group that performed circuit weight training for muscular endurance. Weight training groups were performed three times a week for 10 weeks with 60 minutes a day. For muscle hypertrophy weight training, performed 8 to 10 repetitions of one event in with an intensity of 80% 1 repetition maximum (RM), and 60 seconds of rest between events and repeat 3 sets, the rest period between sets was 3 minutes. For muscular endurance circuit weight training, performed 30 to 40 repetitions of one event in with an intensity of 40% 1 RM, and 30 seconds of rest between events and repeat 3 sets, the rest period between sets was 1 minute. Results: First, weight training to improve muscle hypertrophy and muscular endurance for 10 weeks increased muscle tone in both groups. The biceps brachii and quadriceps muscles increased more in the hypertrophic weight training group, and in the muscular endurance circuit weight training group, the triceps brachii and hamstring muscles were more increased. Second, waist to hip ratio showed a significant decrease in both groups, especially in the circuit weight training group for improving muscular endurance. Although lean body mass increased in both groups, there was no significant difference between groups, and body mass index did not show any difference between groups. Conclusion: Muscle hypertrophy and muscular endurance weight training increased lean body mass and muscle tone, and in the increase in muscle tone in both groups is thought to have a significant relationship with physical strength mechanisms such as muscle strength following an increase in lean body mass.
Yifei Mao,Zhongtang Xiong,Songxin Wu,Zhiqing Huang,Ruoxian Zhang,Yuqin He,Yuling Peng,Yang Ye,Tianfa Dong,Hui Mai 한국유방암학회 2022 Journal of breast cancer Vol.25 No.2
Purpose: Knowing the distinction between benign and borderline/malignant phyllodes tumors (PTs) can help in the surgical treatment course. Herein, we investigated the value of magnetic resonance imaging-based texture analysis (MRI-TA) in differentiating between benign and borderline/malignant PTs. Methods: Forty-three women with 44 histologically proven PTs underwent breast MRI before surgery and were classified into benign (n = 26) and borderline/malignant groups (n = 18 [15 borderline, 3 malignant]). Clinical and routine MRI parameters (CRMP) and MRI-TA were used to distinguish benign from borderline/malignant PT. In total, 298 texture parameters were extracted from fat-suppression (FS) T2-weighted, FS unenhanced T1-weighted, and FS first-enhanced T1-weighted sequences. To evaluate the diagnostic performance, receiver operating characteristic curve analysis was performed for the K-nearest neighbor classifier trained with significantly different parameters of CRMP, MRI sequence-based TA, and the combination strategy. Results: Compared with benign PTs, borderline/malignant ones presented a higher local recurrence (p = 0.045); larger size (p < 0.001); different time-intensity curve pattern (p = 0.010); and higher frequency of strong lobulation (p = 0.024), septation enhancement (p = 0.048), cystic component (p = 0.023), and irregular cystic wall (p = 0.045). TA of FS T2- weighted images (0.86) showed a significantly higher area under the curve (AUC) than that of FS unenhanced T1-weighted (0.65, p = 0.010) or first-enhanced phase (0.72, p = 0.049) images. The texture parameters of FS T2-weighted sequences tended to have a higher AUC than CRMP (0.79, p = 0.404). Additionally, the combination strategy exhibited a similar AUC (0.89, p = 0.622) in comparison with the texture parameters of FS T2-weighted sequences. Conclusion: MRI-TA demonstrated good predictive performance for breast PT pathological grading and could provide surgical planning guidance. Clinical data and routine MRI features were also valuable for grading PTs.
유정성 시각에서의 한, 중, 일, 베트남어고빈도 재귀대명사 의미지도 연구
Yifei;Yue 한국문학언어학회 2018 어문론총 Vol.76 No.-
재귀대명사는 문장에서 이미 나타난 명사나 대명사의 중복을 피하기 위해 쓰이는 특수한 대명사이다. Chomsky가 결속 이론(GB Theory)을 제시한 후, 학자들이 재귀대명사의 결속 특징을 중심으로 연구를 많이 해 왔지만 각 언어에서 재귀대명사의 범위 한정에 대해 의견이 분분하고 재귀대명사의 보편적 지시, 강조, 문맥에서의 3인칭 지시 등 기능도 연구에서 간과되었다. 이 논문은 선행 연구를 바탕으로 한, 중, 일, 베트남어에서의 고빈도 재귀대명사를 선정하고 유정성 이론과 의미지도 모형으로 이 네 가지 언어에서 고빈도 재귀대명사의 의미적 기능을 고찰하였다. 범언어적인 개념공간을 구축하여 의미지도를 그려내고 재귀대명사와 관련된 몇 가지 함축적 보편성을 제시하였다. Since Chomsky put forth the Government and Binding theory, many scholars have studied the anaphora functions of reflexive pronouns. Meanwhile, the scope of reflexive pronouns in each language has not yet been defined, and the semantic functions of reflexive pronouns, such as general reference, emphasis, respect expression, and third-person instructions in discourse, have also been ignored. This paper first determines the study range of high-frequency reflexive pronouns in Korean, Chinese, Japanese, and Vietnamese based on previous studies. With the help of animacy theory and the semantic map model, it then studies the semantic functions of high-frequency reflexive pronouns in the above four languages. On this basis, this paper constructs a conceptual space of reflexive pronouns, draws semantic maps, and presents several common linguistic typology universalities related to reflexive pronouns.
Energy Efficient Topology Control for Multi-Hop Relay Cellular Networks Based on Flow Management
Yifei Wei,Yongfu Hou,Li Li,Mei Song 한국통신학회 2017 Journal of communications and networks Vol.19 No.6
The rapid expansion of mobile communication networkshas led to a significant increase of energy consumption, and the energyconsumption of wireless access networks accounted for nearly90%. As an important form of the wireless access networks, multihoprelay networks have been widely deployed in the existing cellularnetworks. Consequently, improving the energy efficient ofmulti-hop relay cellular networks is crucial for communication networks. In this paper, we design an energy flow management frameworkfor multi-hop relay cellular networks, which contains routingplanning, traffic adjustment and power allocation. In orderto reduce the energy consumption and guarantee the system capacity,a heuristic algorithm is designed in this paper, which mixesthe ant colony algorithm with convex optimization theory. In orderto verify the effect of the proposed algorithm, we make numericalsimulation and compare it with other network management strategies,such as ant colony algorithm, shortest path routing strategyand greedy algorithm. Simulation results show that by our algorithm,the energy consumption can be reduced compared with theant colony algorithm, shortest path and greedy algorithm while ensuringthe demand of quality of service (QoS).