1,460 research outputs found

    Implementation of Cloth Simulation Using Parallel Computing on Mobile Device

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    Physically based modeling and simulation is an important technique for deformable object simulation, which is widely used to represent the realistic shape change and movement of objects for mobile game or 3D simulation. However, they require the high computational cost for representing the physical phenomenon on deformable objects when it applied on mobile device. In this paper, we designed and implemented the cloth simulation for deformable object simulation using the parallel technique on mobile device to optimize the computational burden. We especially applied GPU parallel technique for the integration solving process such as Euler, Midpoint, 4th-order Runge-Kutta method to estimate the particles' next status using positions and velocities. Also we applied multi-thread parallel technique for calculating the spring force. Then we compared the performance of each integration methods between under only CPU and CPU with GPU on mobile device. Also we compared the computing time of spring calculation between only CPU and using CPU multi-thread

    An arrhythmia classification algorithm using a dedicated wavelet adapted to different subjects

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    <p>Abstract</p> <p>Background</p> <p>Numerous studies have been conducted regarding a heartbeat classification algorithm over the past several decades. However, many algorithms have also been studied to acquire robust performance, as biosignals have a large amount of variation among individuals. Various methods have been proposed to reduce the differences coming from personal characteristics, but these expand the differences caused by arrhythmia.</p> <p>Methods</p> <p>In this paper, an arrhythmia classification algorithm using a dedicated wavelet adapted to individual subjects is proposed. We reduced the performance variation using dedicated wavelets, as in the ECG morphologies of the subjects. The proposed algorithm utilizes morphological filtering and a continuous wavelet transform with a dedicated wavelet. A principal component analysis and linear discriminant analysis were utilized to compress the morphological data transformed by the dedicated wavelets. An extreme learning machine was used as a classifier in the proposed algorithm.</p> <p>Results</p> <p>A performance evaluation was conducted with the MIT-BIH arrhythmia database. The results showed a high sensitivity of 97.51%, specificity of 85.07%, accuracy of 97.94%, and a positive predictive value of 97.26%.</p> <p>Conclusions</p> <p>The proposed algorithm achieves better accuracy than other state-of-the-art algorithms with no intrasubject between the training and evaluation datasets. And it significantly reduces the amount of intervention needed by physicians.</p

    Control Method Of Circulating Refrigerant Amount For Heat Pump System

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    A heat pump system requires proper refrigerant charge amount. Once refrigerant is charged into a heat pump system, its charge amount is fixed. For this reason, prediction of optimal refrigerant charge amount is very important in order to yield best performance. Too low charge amount degrades capacity of heat pump. On the other hand, excessive charge amount decreases coefficient of performance (COP). The optimal value of refrigerant charge amount highly depends on secondary fluid temperature conditions. Consequently, fixed charge amount of refrigerant in heat pump shows the best performance only at certain temperature condition. Several ideas have revealed to change charge amount of the heat pump system. One is to have an additional reservoir to store or release refrigerant which is attached to a heat pump system. This method may seem simple but to measure exact amount of refrigerant in reservoir, additional pressure transducer, temperature measurement device, level sensor and other apparatus are required that increase the cost of heat pump. Another idea is to have reservoir between condenser outlet and expansion device. Rajapaksha and Suen (2004) showed that existence of reservoir at this point helps improve capacity while reducing the system COP. In this study, a new method for refrigerant charge amount control technique is presented. It has very simple control logic and requires only a few additional cost factors; several valves and additional tubes are only required. This method is based on different refrigerant phase distribution at each point of inlet and outlet of components in heat pump system. In a simple cycle heat pump system, refrigerant at condenser outlet (before expansion device) is in a subcooled liquid state at high pressure, while refrigerant is in a superheated vapor state at evaporator outlet (before compressor inlet) at low pressure. This technique regulates refrigerant charge by holding some volume of refrigerant in the connecting tube of considerable volume installed between the condenser outlet and the evaporator outlet. Using several solenoid valves (on/off) desired amount of refrigerant can be stored into a volume provided by a connecting tube. This connected volume is referred as ‘stagnation volume’ (Vstag). When one of this installed valve is closed and the rest of the valves are open, certain amount of refrigerant is stored in the stagnation volume (Vstag) while operating heat pump system. If closed valve is adjacent to condenser outlet, charge amount to the heat pump system increases while the charge is reduced when the valve adjacent to evaporator outlet is closed. This method is numerically verified and there are very little variation of COP. Therefore, heat pump can be operated at optimized circulating amount of refrigerant in spite of the secondary fluid temperature variation during heating or cooling operation

    Intratumoral heterogeneity characterized by pretreatment PET in non-small cell lung cancer patients predicts progression-free survival on EGFR tyrosine kinase inhibitor

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    Intratumoral heterogeneity has been suggested to be an important resistance mechanism leading to treatment failure. We hypothesized that radiologic images could be an alternative method for identification of tumor heterogeneity. We tested heterogeneity textural parameters on pretreatment FDG-PET/CT in order to assess the predictive value of target therapy. Recurred or metastatic non-small cell lung cancer (NSCLC) subjects with an activating EGFR mutation treated with either gefitinib or erlotinib were reviewed. An exploratory data set (n = 161) and a validation data set (n = 21) were evaluated, and eight parameters were selected for survival analysis. The optimal cutoff value was determined by the recursive partitioning method, and the predictive value was calculated using Harrell's C-index. Univariate analysis revealed that all eight parameters showed an increased hazard ratio (HR) for progression- free survival (PFS). The highest HR was 6.41 (P< 0.01) with co-occurrence (Co) entropy. Increased risk remained present after adjusting for initial stage, performance status (PS), and metabolic volume (MV) (aHR: 4.86, P< 0.01). Textural parameters were found to have an incremental predictive value of early EGFR tyrosine kinase inhibitor (TKI) failure compared to that of the base model of the stage and PS (C-index 0.596 vs. 0.662, P = 0.02, by Co entropy). Heterogeneity textural parameters acquired from pretreatment FDG-PET/CT are highly predictive factors for PFS of EGFR TKI in EGFR-mutated NSCLC patients. These parameters are easily applicable to the identification of a subpopulation at increased risk of early EGFR TKI failure. Correlation to genomic alteration should be determined in future studies.

    A Rare Case of Radial Arteriovenous Fistula After Coronary Angiography

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    The percutaneous transfemoral approach has been routinely used for cardiac catheterization and coronary angioplasty. Local vascular complications following angioplasty are seen in 5% to 10% of patients, especially in those who need prolonged anticoagulation. Transradial access for coronary procedures dramatically reduces access site complications. We report a rare case of radial arteriovenous fistula, which developed after coronary angiography perfomed using the transradial approach

    A Rare Case of Radial Arteriovenous Fistula After Coronary Angiography

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    The percutaneous transfemoral approach has been routinely used for cardiac catheterization and coronary angioplasty. Local vascular complications following angioplasty are seen in 5% to 10% of patients, especially in those who need prolonged anticoagulation. Transradial access for coronary procedures dramatically reduces access site complications. We report a rare case of radial arteriovenous fistula, which developed after coronary angiography perfomed using the transradial approach

    Population pharmacokinetics of everolimus in patients with seizures associated with focal cortical dysplasia

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    Background: Everolimus is an inhibitor of mammalian target of rapamycin complex 1. As mutations in TSC1 and TSC2, which cause partial-onset seizures associated with TSC, were found in focal cortical dysplasia type Ⅱ (FCD Ⅱ) patients, a clinical trial has been performed to explore the efficacy and safety of everolimus in FCD patients. However, no dosage regimen was determined to treat FCD II. To recommend an optimal dose regimen for FCD patients, a population pharmacokinetic model of everolimus in FCD patients was developed.Methods: The data of everolimus were collected from September 2017 to May 2020 in a tertiary-level hospital in Korea. The model was developed using NONMEM® software version 7.4.1 (Icon Development Solutions, Ellicott City, MD, United States).Results: The population pharmacokinetics of everolimus was described as the one-compartment model with first-order absorption, with the effect of BSA on clearance. The final model was built as follows: TVCL = 12.5 + 9.71 × (BSA/1.5), TVV = 293, and TVKA = 0.585. As a result of simulation, a dose higher than 7 mg/m2 is needed in patients with BSA 0.5 m2, and a dose higher than 6 mg/m2 is needed in patients with BSA 0.7 m2. A dose of 4.5 mg/m2 is enough in the population with BSA higher than 1.5 m2 to meet the target trough range of 5–15 ng/mL.Conclusion: Based on the developed pharmacokinetics model, the optimal dose of everolimus in practice was recommended by considering the available strengths of Afinitor disperz®, 2 mg, 3 mg, and 5 mg
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