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Voltage Source Inverter Drive Using Error-compensated Pulse Width Modulation
Chen, Keng-Yuan,Hu, Jwu-Sheng,Lin, Jau-Nan The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.1
An error-compensated pulse width modulator (ECPWM) is proposed to improve the baseband harmonic performance and the switching loss of voltage source inverters (VSIs). Selecting between harmonic distortion and switching loss is a design tradeoff in the conventional space vector pulse width modulation. In this work, an accumulated difference in produced and desired phase voltages is considered to adjust the reference signal. This mechanism can compensate for the voltage error in the previous carrier period. With error compensation every half-carrier period, the proposed ECPWM allows one-half reduction in carrier frequency without scarifying baseband harmonic distortion. The proposed modulator is applied to a three-phase VSI with R-L load and a motor-speed-control system for experiments. The measured efficiency and operating temperature of switches confirm the effectiveness of the proposed scheme.
Voltage Source Inverter Drive Using Error-compensated Pulse Width Modulation
Keng-Yuan Chen,Jwu-Sheng Hu,Jau-Nan Lin 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.1
An error-compensated pulse width modulator (ECPWM) is proposed to improve the baseband harmonic performance and the switching loss of voltage source inverters (VSIs). Selecting between harmonic distortion and switching loss is a design tradeoff in the conventional space vector pulse width modulation. In this work, an accumulated difference in produced and desired phase voltages is considered to adjust the reference signal. This mechanism can compensate for the voltage error in the previous carrier period. With error compensation every half-carrier period, the proposed ECPWM allows one-half reduction in carrier frequency without scarifying baseband harmonic distortion. The proposed modulator is applied to a three-phase VSI with R–L load and a motor-speed-control system for experiments. The measured efficiency and operating temperature of switches confirm the effectiveness of the proposed scheme.
Turning Dynamics and Equilibrium of Two-Wheeled Vehicles
Chih-Keng Chen,Thanh-Son Dao,Chih-Kai Yang 대한기계학회 2005 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.19 No.1S
The equations of motion of two-wheeled vehicles, e g bicycles or motorcycles, are developed by using Lagrange's equations for quasi-coordinates The pure rolling constraints between the ground and the two wheels ale considered m the dynamical equations of the system For each wheel, two nonholonomic and two holonomic constraints are introduced in a set of differentials algebraic equations (DAE) The constraint Jacobian matrix is obtained by collecting all the constraint equations and converting them into the velocity form Equilibrium, an algorithm for searching for equilibrium points of two-wheeled vehicles and the associated problems are discussed Formulae for calculating the radii of curvatures of ground-wheel contact paths and the reference point are also given<br/>
IPO Underwriting and Subsequent Lending
Hsuan-Chi Chen,Li-Ping Chen,Keng-Yu Ho,Pei-Shih Weng 한국재무학회 2012 한국재무학회 학술대회 Vol.2012 No.09
This study investigates the relation between IPO underwriting and subsequent lending. We find that when a bank underwrites a firm’s IPO, the bank is more likely to provide the issuer with future loans at a lower cost, compared to banks without an IPO underwriting relationship. The evidence also suggests that the underwriting banks share information surplus with the IPO firms in the post-IPO loans, supporting the cost-saving hypothesis. Finally, when borrowing firms are more satisfied with the IPO outcomes, they are more likely to retain their underwriting banks as subsequent lenders. We find no evidence that underwriting banks would exploit such satisfaction by charging higher interest rates in the post-IPO loans.
Pei-Ju Chen,Keng-Chen Liang,Hui-Chen Lin,Ching-Liang Hsieh,Kuan-Pin Su,Mei-Chu Hung,Lee-Yan Sheen 한국식품영양과학회 2011 Journal of medicinal food Vol.14 No.6
This study adopted the forced-swimming paradigm to induce depressive symptoms in rats and evaluated the effects on learning and memory processing. Furthermore, the effects of the water extract of Gastrodia elata Bl., a well-known Chinese traditional medicine, on amnesia in rats subjected to the forced-swimming procedure were studied. Rats were subjected to the forced-swimming procedure, and the inhibitory avoidance task and Morris water maze were used to assess learning and memory performance. The acquisition of the two tasks was mostly impaired after the 15-minute forced-swimming procedure. Administration of the water extract of G. elata Bl. for 21 consecutive days at a dosage of 0.5 or 1.0 g/kg of body weight significantly improved retention in the inhibitory avoidance test, and the lower dose showed a better effect than the higher one and the antidepressant fluoxetine (18 mg/kg of body weight). In the Morris water maze, the lower dose of the water extract of G. elata Bl. significantly improved retention by shortening escape latency in the first test session and increasing the time in searching the target zone during the probe test. These findings suggest that water extracts of G. elata Bl. ameliorate the learning and memory deficits induced by forced swimming.
Yu-Li Chen,Kung-Liahng Wang,Min-Yu Chen,Mu-Hsien Yu,Chen-Hsuan Wu,Yu-Min Ke,Yi-Jen Chen,Yin-Yi Chang,Keng-Fu Hsu,Ming-Shyen Yen 대한부인종양학회 2013 Journal of Gynecologic Oncology Vol.24 No.1
Objective: To evaluate the clinical outcome and parameters related to coexisting endometrial carcinoma in women with tissuediagnosed endometrial hyperplasia. Methods: Between January 1991 and December 2009, three hundred and eighty-six patients with the presumptive diagnosis of endometrial hyperplasia were retrieved. Among these, one hundred and twenty-five patients were identified as having coexisting endometrial carcinoma in hysterectomy specimens. The three hundred and eighty-six patients were divided into two groups: the hyperplasia-benign group (261 cases) and the hyperplasia-malignant group (125 cases). Several clinical parameters including age, menopausal status, history of abnormal uterine bleeding, obstetrical history, medical history of diabetes and hypertension, BMI, and preoperative pathologic results were investigated. Results: Age ≥53 (odds ratio [OR], 2.40; 95% confidence interval [CI], 1.26 to 4.57), menopausal status (OR, 2.07; 95% CI, 1.14to 3.76), diabetes history (OR, 7.33; 95% CI, 2.79 to 19.26), abnormal uterine bleeding (OR, 3.99; 95% CI, 1.22 to 13.02), atypical endometrial hyperplasia (OR, 7.38; 95% CI, 4.03 to 13.49), and body mass index ≥27 (OR, 3.24; 95% CI, 1.76 to 5.97) were independent risk factors for prediction of endometrial hyperplasia coexisting with endometrial carcinoma. The diagnostic efficacy of atypical endometrial hyperplasia to predict the endometrial hyperplasia coexisting with endometrial carcinoma was better than or similar to those of other independent factors and combinations of these factors. Conclusion: Coexisting malignancy should be considered when examining endometrial hyperplasia patients with the related risk factors, especially atypical endometrial hyperplasia.
Hung-Chun Fu,Jen-Ruei Chen,Min-Yu Chen,Keng-Fu Hsu,Wen-Fang Cheng,An Jen Chiang,Yu-Min Ke,Yu-Chieh Chen,Yin-Yi Chang,Chia-Yen Huang,Chieh-Yi Kang,Yuan-Yee Kan,Sheng-Mou Hsiao,Ming-Shyen Yen 대한부인종양학회 2018 Journal of Gynecologic Oncology Vol.29 No.5
Objective: Choice of hysterectomy and adjuvant treatment for International Federation of Gynecology and Obstetrics (FIGO) 2009 stage II endometrioid endometrial cancer (EEC) is still controversial. Aims of this study were to evaluate survival benefits and adverse effects of different hysterectomies with or without adjuvant radiotherapy (RT), and to identify prognostic factors. Methods: The patients at 14 member hospitals of the Taiwanese Gynecologic Oncology Group from 1992 to 2013 were retrospectively investigated. Patients were divided into simple hysterectomy (SH) alone, SH with RT, radical hysterectomy (RH) alone, and RH with RT groups. Endpoints were recurrence-free survival (RFS), overall survival (OS), disease-specific survival (DSS), adverse effects and prognostic factors for survival. Results: Total of 246 patients were enrolled. The 5-year RFS, OS, DSS and recurrence rates for the entire cohort were 89.5%, 94.3%, 96.2% and 10.2%, respectively. Patients receiving RH had more adverse effects including blood loss (p<0.001), recurrent urinary tract infections (p=0.013), and leg lymphedema (p=0.038). Age over 50-year (HR=9.2; 95% confidence interval [CI], 1.2–70.9) and grade 3 histology (HR=7.28; 95% CI, 1.45–36.6) were independent predictors of OS. Grade 3 histology was an independent predictor of RFS (HR=5.13; 95% CI, 1.38–19.1) and DSS (HR=5.97; 95% CI, 1.06–58.7). Patients receiving adjuvant RT had lower locoregional recurrence (p=0.046), but no impact on survival. Conclusion: Different treatment modalities yield similar survival outcomes. Patients receiving SH with RT had lower locoregional recurrent with acceptable morbidity. Age and tumor grading remained significant predictors for survival among patients with FIGO 2009 stage II EEC.
Continuous Critic Learning for Robot Control in Physical Human-Robot Interaction
Chen Wang,Yanan Li,Shuzhi Sam Ge,Keng Peng Tee,Tong Heng Lee 제어로봇시스템학회 2013 제어로봇시스템학회 국제학술대회 논문집 Vol.2013 No.10
In this paper, optimal impedance adaptation is investigated for interaction control in constrained motion. The external environment is modeled as a linear system with parameter matrices completely unknown and continuous critic learning is adopted for interaction control. The desired impedance is obtained which leads to an optimal realization of the trajectory tracking and force regulation. As no particular system information is required in the whole process, the proposed interaction control provides a feasible solution to a large number of applications. The validity of the proposed method is verified through simulation studies.
Middle Cerebral Artery Compromise Associated With Post-traumatic Hydrocephalus: A Case Report
Tzu-Ning Chen,Keng-Liang Kuo,Chih-Lung Lin,Yu-Feng Su 대한신경손상학회 2023 Korean Journal of Neurotrauma Vol.19 No.4
Post-traumatic hydrocephalus (PTH) is a commonly encountered complication following decompressive craniectomy, and is usually characterized by symptoms including headache, nausea, vomiting, and papilledema. Extracranial herniation accompanied by hemiplegia is a rare complication in patients with PTH who underwent craniectomy after subdural hematoma removal. We report a case of PTH that presented with extracranial herniation within one month of decompressive craniectomy. Following ventriculoperitoneal shunt implantation, left hemiplegia improved dramatically with restoration of the left middle cerebral artery blood flow, which was evident on serial imaging. Vascular compromise is often overshadowed by increased intracranial pressure when clinicians are dealing with traumatic brain injury patients. Delicate neurological and radiological examinations and prompt early interventions could lead to optimal outcomes in patients receiving decompressive craniectomy.