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Wijker, J.J.,de Boer, A.,Ellenbroek, M.H.M. Techno-Press 2015 Advances in aircraft and spacecraft science Vol.2 No.2
To prevent over-testing of the test-item during random vibration testing Scharton proposed and discussed the force limited random vibration testing (FLVT) in a number of publications. Besides the random vibration specification, the total mass and the turn-over frequency of the load (test item), $C^2$ is a very important parameter for FLVT. A number of computational methods to estimate $C^2$ are described in the literature, i.e., the simple and the complex two degrees of freedom system, STDFS and CTDFS, respectively. The motivation of this work is to evaluate the method for the computation of a realistic value of $C^2$ to perform a representative random vibration test based on force limitation, when the adjacent structure (source) description is more or less unknown. Marchand discussed the formal description of getting $C^2$, using the maximum PSD of the acceleration and maximum PSD of the force, both at the interface between load and source. Stevens presented the coupled systems modal approach (CSMA), where simplified asparagus patch models (parallel-oscillator representation) of load and source are connected, consisting of modal effective masses and the spring stiffness's associated with the natural frequencies. When the random acceleration vibration specification is given the CSMA method is suitable to compute the value of the parameter $C^2$. When no mathematical model of the source can be made available, estimations of the value $C^2$ can be find in literature. In this paper a probabilistic mathematical representation of the unknown source is proposed, such that the asparagus patch model of the source can be approximated. The chosen probabilistic design parameters have a uniform distribution. The computation of the value $C^2$ can be done in conjunction with the CSMA method, knowing the apparent mass of the load and the random acceleration specification at the interface between load and source, respectively. Data of two cases available from literature have been analyzed and discussed to get more knowledge about the applicability of the probabilistic method.
Malika Kengsakul,Gatske M. Nieuwenhuyzen-de Boer,Suwasin Udomkarnjananun,Stephen J. Kerr,Christa D. Niehot,Heleen J. van Beekhuizen 대한부인종양학회 2022 Journal of Gynecologic Oncology Vol.33 No.4
Objective: Advances in ovarian cancer cytoreductive surgery have enabled more extensive procedures to achieve maximal cytoreduction but with a consequent increase in postoperative morbidity and mortality. The aim of this study was to evaluate factors for postoperative morbidity after extensive cytoreductive surgery for primary epithelial ovarian cancer (EOC), particularly those which may be modifiable. Methods: Electronic databases were searched. Meta-analysis was conducted using random- effects models. Results: Fifteen relevant studies, involving 15,325 ovarian cancer patients, were included in this review. Severe 30-day postoperative complications occurred in 2,357 (15.4%) patients. The postoperative mortality rate was 1.92%. Meta-analysis demonstrated that patient with following risk factors; age (p<0.001), Eastern Cooperative Oncology Group score >0 (p=0.001), albumin level <3.5 g/dL (p<0.001), presence of ascites on CT scan (p=0.013), stage IV disease (p<0.001) and extensive surgical procedure (p<0.001) has a significantly increase risk of developing postoperative complications. Surgical procedures including peritonectomy (p=0.012), splenectomy (p<0.001) and colon surgery (p<0.001) were significant predictors for postoperative complications. Moreover, we found that patients who received neoadjuvant chemotherapy followed by interval debulking surgery (NACT-IDS) had a lower risk of developing severe complications compared to those who underwent primary debulking surgery (PDS) (p<0.001). Conclusion: Our study demonstrated that patient performance status and hypoalbuminemia were the only significant adjustable preoperative risk factors associated with postoperative complications. Patients who underwent NACT-IDS had a lower risk of developing severe complications compared to PDS.
Improved QRS Detection Algorithm using Dynamic Thresholds
Mohamed Elgendi,Mirjam Jonkman,Friso De Boer 보안공학연구지원센터 2009 International Journal of Hybrid Information Techno Vol.2 No.1
The accurate detection of QRS complexes is important for ECG signal analysis. This paper presents an improved version of a QRS detector based on an adaptive quantized threshold. The algorithm achieves high detection rates by using automatic thresholds instead of predetermined static thresholds. We improved the number of detected QRS in non-stationary random arrhythmic ECG signals by applying a secondary threshold. The performance of the algorithm was tested on 19 records of the MIT/BIH Arrhythmia Database resulting in 97.5% sensitivity and 99.9% positive predictivity.