Multi-objective optimization of semi-submersible platforms using particle swam optimization algorithm based on surrogate model

An Innovative Semi-submersible platform Optimization Program (ISOP) has been developed to solve the multi-objective optimization problem for semi-submersible platforms (SEMI). Three types of SEMIs, including semi-submersible floating production unit (SEMI FPU), heave and vortex induced motion (VIM) suppressed semi-submersible (HVS) and semi-submersible floating drilling unit (SEMI FDU) are selected for case studies. The hydrodynamic performances of three types of semi-submersible platforms are analyzed by using panel method and Morison's equation. In order to improve the computing efficiency, the hydrodynamic performances for different hull forms during optimization process are estimated by the surrogate models, which are built by artificial neural network prediction method and Inverse Multi-Quadric (IMQ) radial basis function (RBF). The accuracy of surrogate models is ensured by performing leave-one-out cross validation (LOOCV). The most probable maximum (MPM) heave motion and total weight, representing the safety and economy, respectively, are chosen as the two objectives for optimization. The transverse metacentric height, the MPM surge motion, and the most probable minimum (MPMin) airgap are selected as constraints. Based on surrogate models, multi-objective particle swarm optimization (MOPSO) is employed to search for the Pareto-optimal solutions. A Computational Fluid Dynamics (CFD) tool is adopted to validate the proposed model for the prediction of the motion responses. By comparing the obtained Pareto-optimal solutions with the initial design using simple panel method plus Morison's equation, it is confirmed that the MPM heave motions for SEMI FPU, HVS and SEMI FDU can be suppressed by up to 12.68%, 11.92%, and 14.96%, respectively, and the total weights can be reduced by up to 12.16%, 13.00%, and 24.91%, respectively. Through the detailed analyses of optimization results, the most efficient design strategies for semi-submersible platforms are discussed and proposed

Text-driven Prompt Generation for Vision-Language Models in Federated Learning

Prompt learning for vision-language models, e.g., CoOp, has shown great success in adapting CLIP to different downstream tasks, making it a promising solution for federated learning due to computational reasons. Existing prompt learning techniques replace hand-crafted text prompts with learned vectors that offer improvements on seen classes, but struggle to generalize to unseen classes. Our work addresses this challenge by proposing Federated Text-driven Prompt Generation (FedTPG), which learns a unified prompt generation network across multiple remote clients in a scalable manner. The prompt generation network is conditioned on task-related text input, thus is context-aware, making it suitable to generalize for both seen and unseen classes. Our comprehensive empirical evaluations on nine diverse image classification datasets show that our method is superior to existing federated prompt learning methods, that achieve overall better generalization on both seen and unseen classes and is also generalizable to unseen datasets

Multilevel Amplitude Regeneration of PAM-4 Signals using a Nonlinear Optical Loop Mirror

Multilevel amplitude regeneration of return-to-zero PAM-4 signals is experimentally demonstrated using a single NOLM unit. The noise suppression capability at each amplitude level is characterized, and Q2-factor improvement of 0.92dB is achieved by optimizing input signal power and distortion strengt

Reducing Crosstalk of Silicon-based Optical Switch with All-optical Multi-wavelength Regenerator

Improving crosstalk performance of Mach–Zehnder-interferometer-type optical switches is experimentally investigated by use of an all-optical multi-wavelength regenerator. Extinction ratio and bit error rate of WDM signals are simultaneously improved in proposed regenerative optical switching

All-optical multilevel regeneration in nonlinear optical loop mirror

An all-optical multilevel amplitude regenerator is optimized based on the transmission response of a nonlinear optical loop mirror (NOLM). Three regenerative regions defined by the power-transfer-function (PTF) slope of less than 1 are obtained, and noise suppression is shown for a PAM4 signal. Using amplitude dithering we were able to experimentally characterize the transfer function slope and confirm the theoretical predictions

Multi-objective optimization of Tension Leg Platform using evolutionary algorithm based on surrogate model

An Innovative Tension Leg Platform (TLP) Optimization Program, called ITOP, has been developed to solve the multi-objective optimization problem for TLP. We first examine the hydrodynamic behavior of a base TLP for wave headings between 0∘ and 45∘. The numerical results show that the maximum heave and surge motion responses occur in 0∘ wave heading in long-crest waves. It is found that the dynamic tension of No. 8 tendon is larger than the other tendons and reaches its maximum in 45∘ wave heading. It can be attributed to the fact that heave and pitch motions are almost out of phase for wave periods between 10 and 15 s. Because the maximum wave elevation occurs near the northeast column and the vertical motion is very small, the minimum airgap occurs there. Moreover, a surrogate model based on radial basis function (RBF) has been built and adopted to estimate the hydrodynamic performance of TLP. A multi-objective evolutionary algorithm, Non-dominated Sorting Genetic Algorithm II (NSGAII), is employed to find the Pareto-optimal solutions. By comprehensive and systematic computations and analyses, it is revealed that the maximum dynamic tension shows positive correlation with pontoon height and width, but negative correlation with hull draft, column spacing, and column diameter. The most efficient modification strategy for design is proposed to reduce the maximum dynamic tendon tension. According to the strategy, the column spacing, draft, and column diameter should be increased in sequence. By applying this strategy, the maximum dynamic tendon tensions can be reduced while the total weight of the platform is minimized as much as possible

Mechanical thrombectomy with intra-arterial alteplase provided better functional outcomes for AIS-LVO: a meta-analysis

BackgroundSeveral clinical trials have shown that intra-arterial thrombolysis using alteplase during mechanical thrombectomy (MT) has a better outcome than MT alone in ischemic stroke management. We performed the current meta-analysis to estimate the efficacy and safety of MT with intra-arterial alteplase therapy.MethodsThe MEDLINE, Embase, Cochrane Library, and ClinicalTrials.gov databases were searched up to Mar. 2022 to identify the clinical trials that compared MT alone versus MT with intra-arterial alteplase therapy. STATA 16.0 was used for statistical analysis. The odds ratios (ORs) and 95% confidence intervals (95%CIs) were calculated with a random effect model.ResultsSeven studies involving 1,083 participants were included. The primary outcomes were better functional outcomes, defined as a modified Rankin Scale (mRS) score between 0 and 2 at 90  days, and successful recanalization, defined as a modified thrombolysis in cerebral infarction (mTICI) score  ≥  2b. Compared to MT alone, MT with intra-arterial alteplase did not lead to higher mTICI scores (OR 1.58, 95%CI 0.94 to 2.67, p = 0.085, I2 = 16.8%) but did lead to better mRS (OR 1.37, 95%CI 1.01 to 1.86, p = 0.044). There was no increase in mortality or bleeding events in the overall or subgroup analyses.ConclusionMT with intra-arterial alteplase did not improve the recanalization rate but provided better functional outcomes. The intervention did not increase adverse effects in any subgroup at the same time.Clinical trial registrationhttp://inplasy.com, identifier INPLASY202240027

Efficacy and safety of the new biopsy strategy combining 6-core systematic and 3-core MRI-targeted biopsy in the detection of prostate cancer: Study protocol for a randomized controlled trial

BackgroundRecent EAU guideline strongly recommended combined targeted biopsy (TBx) with systematic biopsy (SBx) for biopsy naïve patients with suspected multiparametric magnetic resonance imaging (mpMRI) lesions; However, the clinical goal is to find out how to determine the optimal SBx and TBx cores for biopsy in order to maximize the detection of csPCa and minimize the associated defects. This study aims to assess the efficacy and safety of the new biopsy strategy combining 6-core systematic and 3-core MRI- TBx compared to 12-core systematic and 3-core MRI-TBx strategy.MethodsThis is a single-center, prospectively randomized controlled clinical trial. 280 men meeting inclusion criteria will be recruited and will be randomly allocated to either 6-core systematic plus 3-core MRI-TBx group (Group A) or 12-core systematic plus 3-core MRI-TBx group (Group B). The primary outcome compares the detection rate of PCa and clinically significant prostate cancer(csPCa) between group A and group B. The secondary outcomes compare the participant-reported pain score immediate post biopsy using pain measurement scale; proportion of men with post-biopsy complications and adverse events (Time frame: 7 days post biopsy, 30 days post biopsy); proportion of the men who undergo radical prostatectomy and have cancer upgraded histopathology from the biopsy to the radical prostatectomy.Results and DiscussionA new biopsy strategy should be developed with the goal of minimizing procedure invasion, our study will provide the results of efficacy and safety of the new biopsy strategy (6-core systematic and 3-core MRI-TBx) in biopsy naïve men with suspicious mpMRI lesion in comparison with 12-core systematic and 3-core MRI-TBx.Trial registrationChinese Clinical Trial Registry, ChiCTR2200056437; http://www.chictr.org.cn/edit.aspx?pid=151413&htm=