Pulsed low-dose rate radiotherapy for recurrent bone sarcomas: case reports and brief review

Ru Xin Wong(Ru Xin Wong ),Zubin Master(Zubin Master ),Eric Pang(Eric Pang ),Valerie Yang(Valerie Yang ),Wen Shen Looi(Wen Shen Looi ) 대한방사선종양학회 2024 Radiation Oncology Journal Vol.42 No.1

Purpose: Re-irradiation for bulky recurrent sarcoma carries significant risks. Pulsed low-dose rate radiotherapy (PLDR) is an attractive option for re-irradiation due to inherent radiobiological advantages. Materials and Methods: We present two patients who underwent re-irradiation using PLDR technique, followed by a literature review. Results: The first case is that of a 76-year-old male who developed an in-field recurrence of a bulky pelvic bone high-grade chondrosarcoma after he was treated with definitive radiotherapy using helical TomoTherapy with a total dose of 66 Gy. The patient was re-irradiated using PLDR with a shrinking field technique; 50 Gy in 2 Gy fractions followed by a boost of 20 Gy in 2 Gy fractions. The patient remains disease-free without significant toxicity 60 months post-irradiation. The second case is that of an 82-year-old female who was treated with a definitive irradiation of 66 Gy in 33 fractions for a right shoulder grade II chondrosarcoma. She developed an in-field recurrence 28 months later and presented with bulky disease causing brachial plexopathy and lymphedema. The patient was re-irradiated with a palliative intent to a total dose of 50 Gy in 2 Gy fractions over 5 weeks using PLDR. Brachial plexopathy resolved shortly after re-irradiation, but local progression near the surface was evident 8 months later. She passed away from unrelated causes 11 months later. Conclusion: We present two cases highlighting our early experience with PLDR, which was effective in the re-irradiation of recurrent bony sarcoma. Our study highlights PLDR as an option for re-irradiation in recurrent unresectable tumors.

A Video Traffic Flow Detection System Based on Machine Vision

Xin-Xin Wang,Xiao-Ming Zhao,Yu Shen 한국정보처리학회 2019 Journal of information processing systems Vol.15 No.5

This study proposes a novel video traffic flow detection method based on machine vision technology. The threeframedifference method, which is one kind of a motion evaluation method, is used to establish initialbackground image, and then a statistical scoring strategy is chosen to update background image in real time. Finally, the background difference method is used for detecting the moving objects. Meanwhile, a simple buteffective shadow elimination method is introduced to improve the accuracy of the detection for moving objects. Furthermore, the study also proposes a vehicle matching and tracking strategy by combining characteristics,such as vehicle’s location information, color information and fractal dimension information. Experimentalresults show that this detection method could quickly and effectively detect various traffic flow parameters,laying a solid foundation for enhancing the degree of automation for traffic management.

ON LOCALIZATION IN HOMOTOPY THEORY

SHEN, XIN-YAO TOPOLOGY AND GEOMETRY RESEARCH CENTER 1995 Proceedings of the Topology and Geometry Research Vol.6 No.-

A Robust Dynamic Decoupling Control Scheme for PMSM Current Loops Based on Improved Sliding Mode Observer

Shen, Hanlin,Luo, Xin,Liang, Guilin,Shen, Anwen The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.6

A complete current loop decoupling control strategy based on a sliding mode observer (SMO) is proposed to eliminate the influence of current dynamic coupling and back electromotive force (EMF) in the vector control of permanent magnet synchronous motors. With this strategy, current dynamic decoupling and back EMF compensation can be simultaneously achieved. Unlike conventional methods, the proposed strategy can avoid the disturbances caused by the parametric variations of motor systems and maintain the advantages of proportional integral (PI) controllers, which are robust and easy to operate. An improved SMO, which uses a special PI regulator other than a linear saturation function as the equivalent control law in the boundary layer of a sliding surface, is proposed to eliminate the estimated errors caused by the quasi-sliding mode and obtain a satisfactory decoupling performance. The stability and parameter robustness of the proposed strategy are also analyzed. Physical experimental results are presented to verify the validity of the method.

High-Speed Electrical Machines - Applications, Key Issues and Challenges

Jian-Xin Shen 한국자기학회 2017 한국자기학회 학술연구발표회 논문개요집 Vol.2017 No.11

A Video Traffic Flow Detection System Based on Machine Vision

Wang, Xin-Xin,Zhao, Xiao-Ming,Shen, Yu Korea Information Processing Society 2019 Journal of information processing systems Vol.15 No.5

This study proposes a novel video traffic flow detection method based on machine vision technology. The three-frame difference method, which is one kind of a motion evaluation method, is used to establish initial background image, and then a statistical scoring strategy is chosen to update background image in real time. Finally, the background difference method is used for detecting the moving objects. Meanwhile, a simple but effective shadow elimination method is introduced to improve the accuracy of the detection for moving objects. Furthermore, the study also proposes a vehicle matching and tracking strategy by combining characteristics, such as vehicle's location information, color information and fractal dimension information. Experimental results show that this detection method could quickly and effectively detect various traffic flow parameters, laying a solid foundation for enhancing the degree of automation for traffic management.

A Robust Dynamic Decoupling Control Scheme for PMSM Current Loops Based on Improved Sliding Mode Observer

Hanlin Shen,Xin Luo,Guilin Liang,Anwen Shen 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.6

A complete current loop decoupling control strategy based on a sliding mode observer (SMO) is proposed to eliminate the influence of current dynamic coupling and back electromotive force (EMF) in the vector control of permanent magnet synchronous motors. With this strategy, current dynamic decoupling and back EMF compensation can be simultaneously achieved. Unlike conventional methods, the proposed strategy can avoid the disturbances caused by the parametric variations of motor systems and maintain the advantages of proportional integral (PI) controllers, which are robust and easy to operate. An improved SMO, which uses a special PI regulator other than a linear saturation function as the equivalent control law in the boundary layer of a sliding surface, is proposed to eliminate the estimated errors caused by the quasi-sliding mode and obtain a satisfactory decoupling performance. The stability and parameter robustness of the proposed strategy are also analyzed. Physical experimental results are presented to verify the validity of the method.

Comparative Study on Single Pulse and Dual Pulses Variable Width Control Strategies for High-Speed PM BLDC Motor Drive

Jian-Xin Shen,Xue-Fei Qin,Wei-Zhong Fei,Yun-Chong Wang 한국자기학회 2019 Journal of Magnetics Vol.24 No.2

Pulse width modulation (PWM) of voltage source inverter (VSI) is common for speed regulation of permanent magnet (PM) brushless direct-current (BLDC) motor drives. However, when the motor runs at high speed, the conventional PWM technique may become unfeasible due to the low carrier ratio of inverter, which makes the motor current distorted and the motor core loss increased significantly. In this paper, two control strategies, namely single pulse variable width (SPVW) and dual pulses variable width (DPVW), are introduced for the high-speed PM BLDC motor drives, and are comprehensively investigated. Finite element method (FEM) is employed to evaluate and compare the drive system performance when using the conventional PWM, and the proposed SPVW and DPVW, respectively. Influence of the control techniques, especially on the loss distribution, is revealed.

A Double Bi-Quad Filter with Wide-Band Resonance Suppression for Servo Systems

Xin Luo,Anwen Shen,Renchao Mao 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.5

In this paper, an algorithm using two bi-quad filters to suppress the wide-band resonance for PMSM servo systems is proposed. This algorithm is based on the double bi-quad filters structure, so it is named, “double bi-quad filter.” The conventional single bi-quad filter method cannot suppress unexpected mechanical terms, which may lead to oscillations on the load side. A double bi-quad filter structure, which can cancel the effects of compliant coupling and suppress wide-band resonance, is realized by inserting a virtual filter after the motor speed output. In practical implementation, the proposed control structure is composed of two bi-quad filters on both the forward and feedback paths of the speed control loop. Both of them collectively complete the wide-band resonance suppression, and the filter on the feedback path can solve the oscillation on the load side. Meanwhile, with this approach, in certain cases, the servo system can be more robust than with the single bi-quad filter method. A step by step design procedure is provided for the proposed algorithm. Finally, its advantages are verified by theoretical analysis and experimental results.

Synergistic Effect and Flame-retardant Properties of Small Molecular Organic Amines and Phosphates

Xin Chen,Junkang Guo,Limei Ren,Shenyong Ren,Baojian Shen,Qiaoxia Guo 한국섬유공학회 2021 Fibers and polymers Vol.22 No.4

The flame-retardant finishing of cotton with pentaerythritol phosphate and small molecule organic amine, such asdiethylenetriamine, triethylenetetramine, diethanolamine, or isopropanolamine, was studied. The mechanical and flameretardantproperties and thermal stability of cotton fabric before and after flame-retardant finishing were investigated. Resultsrevealed that the longitudinal and latitudinal breaking strength increased. The limiting oxygen index increased from 18.7 %to 37.9-39.1 %. Vertical flame burning time and afterglow time decreased from 35.1 and 8.4 s, respectively, to 0 s. Thedamage length decreased from 30 cm to 7.1-8.4 cm. At 700 °C, the residual carbon increased from 17.69 % to 41.48-41.56 %. The experimental results show that the flame-retardant system has good flame retardant and carbonization effectson cotton and good foaming property for combustion. The experimental operation is simple, rapid, and has broad marketprospects.