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      • KCI등재
      • Robust Control Design Based-on Integral Sliding-Mode for Systems with Norm-Bounded Uncertainties

        Chieh-Chuan Feng,Yung-Yeh Lin 제어로봇시스템학회 2011 제어로봇시스템학회 국제학술대회 논문집 Vol.2011 No.10

        Based on the integral sliding-mode control that copes with norm-bounded matched uncertainties, a robust control of L₂-gain performance measure subsequently applied to the system is proposed to handle both nonlinearities and unmatched uncertainties. The similar issue through the use of higher order multimode model has been relaxed. Instead of using exact known multi-mode to express the uncertain system, the norm-bound convex set is a concise way of expressing the model and hence, higher order models needed in the computation can be avoided. In this paper integral sliding-mode control robustly nullifies the matched uncertainties from the first beginning of the process and then, once in the sliding mode, the nonlinearities and unmatched uncertainties are further compensated by the quadratic stability with L₂-gain performance measure to not only stabilize the system but also ensure the satisfaction of performance. The effectiveness is shown in a numerical example.

      • KCI등재

        New Permeable Structure for Controlling Debris Flows in the Wenjiagou Gully

        Yu-feng Liang,Chuan Liang,Hongwei Zhou,Feng-rong Yang,Miao Huo,Jia-wen Zhou 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.11

        Aimed to control debris flows more effectively, we attempt to develop a new structure called a “sloping roof grill dam”, which consists of guidance walls, separation grills and lateral deposit areas. A series of flume tests were performed to verify the function of this new structure, focusing on the trapping efficiency (β ), deceleration efficiency (μ) and coarse-fine sediment separation extents (η) under different conditions of structure and debris flows. Experimental results show that both the trapping and deceleration efficiency increase with a decrease in permeability, whereas the separation extent shown the opposite effect. Multiple regression analysis indicates that β and η are linearly dependent on the permeability, deceleration efficiency and magnitudes of debris flow. In addition, an increase in beam gap can lead to an increase in the impact area downstream for the debris flow after the control of the structure. Finally, a two-level installation of the structure is tested to determine whether there is an enhancement of the debris control, which indicated that although the trapping effect of the two-level structure is considerably greater than that of a single-level structure (2.11 times at maximum), the separation extent of the two-level structure is not distinct and may be even lower.

      • KCI등재

        Inverse Analysis of Inconel 718 Laser-Assisted Milling to Achieve Machined Surface Roughness

        Yixuan Feng,Tsung-Pin Hung,Yu-Ting Lu,Yu-Fu Lin,Fu-Chuan Hsu,Chiu-Feng Lin,Ying-Cheng Lu,Xiaohong Lu,Steven Y. Liang 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.19 No.11

        This manuscript proposes an inverse analysis method for the machined surface roughness in laser-assisted milling on Inconel 718. The method solves the forward problem considering the tool profile and the elastic recovery of machined surface and applies the variance-based recursive method to guide the updating mechanism of process parameters to match the measurements. Subsequently, the inverse analysis identifies four process parameters of feed per tooth, tool tip radius, minimum cutting thickness, and tool tip angle, and finds the optimal solution for target performance, the surface roughness. The measurements are collected under the single beam coaxial laser-assisted milling spindle. The proposed modified Kalman filter algorithm introduces the gain coefficient G when updating the process parameters to improve robustness and accuracy. The inverse analysis is conducted on all measurements, and the average error of target performance is 0.460% when the laser is on and 0.394% when the laser is off. The average difference of process parameters is less than 5%, and the selection process is done in 50 loops within a minute. Therefore, the proposed inverse analysis model is robust, adaptive to different initial guesses and measurements, highly accurate, and saves computation time.

      • Impact of Adjuvant Chemotherapy in Elderly Breast Patients in Taiwan, A Hospital-Based Study

        Lee, Hsiu Chuan,Chen, Wei Yu,Huang, Wen Tsung,Cheng, Kuo Chen,Tian, Yu Feng,Ho, Chung Han,Tsao, Chao Jung,Feng, Yin Hsun Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.10

        Purpose: Decisions as to whether to provide adjuvant treatment in older breast cancer patients remains challenging. Side effects of chemotherapy have to be weighed against life expectancy, comorbidities, functional status, and frailty. To aid decision-making, we retrospectively analyzed 110 women with breast cancer treated with a curative intention from 2006 to 2012. Survival data with clinical and pathological parameters were evaluated to address the role of adjuvant chemotherapy in this study population. Method: A total of 110 elderly (>70 years) patients that received mastectomy at two hospitals in Taiwan were observed retrospectively for a medium of 51 months. After mastectomy, patients received conservative treatment or adjuvant chemotherapy, or hormone therapy following clinical guidelines or physician's preference. Data were collected from the cancer registry system. Results: Median age at diagnosis was 75.7 years. Thirty-five percent of patients received adjuvant chemotherapy, these having a significantly younger age ($mean=74.0{\pm}5.3$ vs $77.5{\pm}5.3$, p<0.001) and higher tumor staging (p=0.003) compared with their non-chemotherapy counterparts.Five-year overall survival was non-significantly higher in patients who received adjuvant chemotherapy (with chemotherapy 64.2% vs without chemotherapy 62.6%, p=0.635), while five-year recurrence free survival was non-significantly lower (with chemotherapy 64.1% vs without chemotherapy 90.5%, p=0.80). Conclusions: In this analysis, adjuvant chemotherapy tended to be given to patients with a younger age and higher tumor staging at our institute. It was not associated with any statistically significant improvement in survival and recurrence rate. Until age specific recommendations are available, physicians must use their clinical judgment and assess the tumor biology with the patient's comorbidities to make the best choice. Clinical trials focusing on this critical issue are warranted.

      • Comparison of Complications of Peripherally Inserted Central Catheters with Ultrasound Guidance or Conventional Methods in Cancer Patients

        Gong, Ping,Huang, Xin-En,Chen, Chuan-Ying,Liu, Jian-Hong,Meng, Ai-Feng,Feng, Ji-Feng Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.5

        Objective: To compare the complications of peripherally inserted central catheters (PICC) by a modified Seldinger technique under ultrasound guidance or the conventional (peel-away cannula) technique. Methods: From February to December of 2010, cancer patients who received PICC at the Department of Chemotherapy in Jiangsu Cancer Hospital were recruited into this study, and designated UPICC if their PICC lines were inserted under ultrasound guidance, otherwise CPICC if were performed by peel-away cannula technique. The rates of successful placement, hemorrhage around the insertion area, phlebitis, comfort of the insertion arm, infection and thrombus related to catheterization were analyzed and compared on days 1, 5 and 6 after PICC and thereafter. Results: A total of 180 cancer patients were recruited, 90 in each group. The rates of successful catheter placement between two groups differed with statistical significance (P <0.05), favoring UPICC. More phlebitis and finger swelling were detected in the CPICC group (P <0.05). From day 6 to the date the catheter was removed and thereafter, more venous thrombosis and a higher rate of discomfort of insertion arms were also observed in the CPICC group. Conclusion: Compared with CPICC, UPICC could improve the rate of successful insertion, reduce catheter related complications and increase comfort of the involved arm, thus deserving to be further investigated in randomized clinical studies.

      • SCIESCOPUS

        Study on mechanical behaviors of large diameter shield tunnel during assembling

        Feng, Kun,Peng, Zuzhao,Wang, Chuang,He, Chuan,Wang, Qianshen,Wang, Wei,Cao, Songyu,Wang, Shimin,Zhang, Haihua Techno-Press 2018 Smart Structures and Systems, An International Jou Vol.21 No.5

        In order to study the mechanical behavior of shield tunnel segments during assembly stage, the in-situ tests and FDM numerical simulation were conducted based on the Foguan Shiziyang Tunnel with large cross-section. Analysis for the load state of the assembling segments in different assembly steps as well as the investigation for the changing of inner forces and longitudinal stress of segments with assembling steps were carried out in this paper. By comparing the tested results with the simulated results, the conclusions and suggestions could be drawn as follows: (1) It is the most significant for the effects on axial force and bending moment caused by the assembly of adjacent segment, followed by the insertion of key segment while the effects in the other assembly steps are relative smaller. With the increasing value of axial force, the negative bending moment turns into positive and remains increasing in most monitored sections, while the bending moment of segment B1and B6 are negative and keeping increasing; (2) The closer the monitored section to the adjacent segments or the key segment, the more significant the internal forces response, and the monitored effects of key segment insertion are more obvious than that of calculation; (3) The axial forces are all in compression during assembling and the monitored values are about 1.5~1.75 times larger than the calculated values, and the monitored values of bending moment are about 2 times the numerical calculation. The bending moment is more sensitive to the segments assembly process compared with axial force, and it will result in the large bending moment of segments during assembling when the construction parameters are not suitable or the assembly error is too large. However, the internal forces in assembly stage are less than those in normal service stage; (4) The distribution of longitudinal stress has strong influence on the changing of the internal forces. The segment side surface and intrados in the middle of two adjacent jacks are the crack-sensitive positions in the early assembly stage, and subsequently segment corners far away from the jacks become the crack-sensitive parts either.

      • KCI등재

        The Physiological Occlusion of the Central Canal May Be a Prerequisite for Syringomyelia Formation

        Chuan Jiang,Xinyu Wang,Chunli Lu,Qian Li,Longbing Ma,Wei Li,Shengyu Cui,Kang Li,Xiang Wang,Yuxin Feng,Fengzeng Jian 대한척추신경외과학회 2023 Neurospine Vol.20 No.4

        Objective: Syringomyelia is a common central nervous system disease characterized by the dilation of the central canal (CC). Regarding the pathogenesis of syringomyelia, cerebrospinal fluid (CSF) circulation obstruction in the subarachnoid space (SAS) of the spinal cord has been widely accepted. However, clinical and animal studies on obstructing the CSF in SAS failed to form syringomyelia, challenging the theory of SAS obstruction. The precise pathogenesis remains unknown. Methods: We utilized an extradural compression rat model to investigate the pathogenesis underlying syringomyelia. Magnetic resonance imaging enabled detection of syringomyelia formation. To assess CSF flow within the SAS, Evans blue was infused into the cisterna magna. Histological analysis allowed morphological examination of the CC. Furthermore, CSF flow through the CC was traced using Ovalbumin Alexa-Flour 647 conjugate (OAF-647). Scanning electron microscopy (SEM) enabled visualization of ependymal cilia. Results: The findings showed that the dura mater below the compression segment exhibited lighter coloration relative to the region above the compression, indicative of partial obstruction within the SAS. However, the degree of SAS occlusion did not significantly differ between syringomyelia (SM-Y group) and those without (SM-N group). Intriguingly, hematoxylin and eosin staining and CSF tracing revealed occlusion of the CC accompanied by reduced CSF flow in the SM-Y group compared to SM-N and control groups. SEM images uncovered impairment of ependymal cilia inside the syringomyelia. Conclusion: CC occlusion may represent a physiological prerequisite for syringomyelia formation, while SAS obstruction serves to initiate disease onset. The impairment of ependymal cilia appears to facilitate progression of syringomyelia.

      • KCI등재

        Establishment of Tripterygium wilfordii Hook. f. Hairy Root Culture and Optimization of Its Culture Conditions for the Production of Triptolide and Wilforine

        ( Chuan Shu Zhu ),( Guo Qeng Miao ),( Jia Guo ),( Yan Bo Huo ),( Xing Zhang ),( Jia Hua Xie ),( Jun Tao Feng ) 한국미생물 · 생명공학회 2014 Journal of microbiology and biotechnology Vol.24 No.6

        In order to solve the shortage of natural Tripterygium wilfordii Hook. f. plant resource for the production of the important secondary metabolites triptolide and wilforine, hairy roots were induced from its root calli by Agrobacterium rhizogenes. Induced hairy roots not only could be maintained and grown well in hormone-free half-strength Murashige and Skoog medium but also could produce sufficient amounts of both triptolide and wilforine. Although hairy roots produced approximately 15% less triptolide than adventitious roots and 10% less wilforine than naturally grown roots, they could grow fast and could be a suitable system for producing both secondary metabolites compared with other tissues. Addition of 50 μM methyl jasmonate (MeJA) could slightly affect hairy root growth, but dramatically stimulated the production of both triptolide and wilforine, whereas 50 μM salicylic acid had no apparent effect on hairy root growth with slightly stimulatory effects on the production of both secondary metabolites. Addition of precursor nicotinic acid, isoleucine, or aspartic acid at the concentration of 500 μM had varying effects on hairy root growth, but none of them had stimulatory effects on triptolide production, and only the former two had slightly beneficial effects on wilforine production. The majority of triptolide produced was secreted into the medium, whereas most of the produced wilforine was retained inside of hairy roots. Our studies provide a promising way to produce triptolide and wilforine in T. wilfordii hairy root cultures combined with MeJA treatment.

      • Structural Maintenance of Chromosomes 4 is a Predictor of Survival and a Novel Therapeutic Target in Colorectal Cancer

        Feng, Xiao-Dong,Song, Qi,Li, Chuan-Wei,Chen, Jian,Tang, Hua-Mei,Peng, Zhi-Hai,Wang, Xue-Chun Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.21

        Background: Structural maintenance of chromosomes 4 (SMC-4) is a chromosomal ATPase which plays an important role in regulate chromosome assembly and segregation. However, the role of SMC-4 in the incidence of malignancies, especially colorectal cancer is still poorly understood. Materials and Methods: We here used quantitative PCR and Western blot analysis to examine SMC-4 mRNA and protein levels in primary colorectal cancer and paired normal colonic mucosa. SMC-4 clinicopathological significance was assessed by immunohistochemical staining in a tissue microarray (TMA) in which 118 cases of primary colorectal cancer were paired with noncancerous tissue. The biological function of SMC-4 knockdown was measured by CCK8 and plate colony formation assays. Fluorescence detection has been used to detect cell cycling and apoptosis. Results: SMC-4 expression was significantly higher in colorectal cancer and associated with T stage, N stage, AJCC stage and differentiation. Knockdown of SMC-4 expression significantly suppressed the proliferation of cancer cells and degraded its malignant degree. Conclusions: Our clinical and experimental data suggest that SMC-4 may contribute to the progression of colorectal carcinogenesis. Our study provides a new therapeutic target for colorectal cancer treatment.

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