Research progress on intelligent optimization techniques for energy-efficient design of ship hull forms

The design optimization of ship hull form based on hydrodynamics theory and simulation-based design (SBD) technologies generally considers ship performance and energy efficiency performance as the design objective, which plays an important role in smart design and manufacturing of green ship. An optimal design of sustainable energy system requires multidisciplinary tools to build ships with the least resistance and energy consumption. Through a systematic approach, this paper presents the research progress of energy-efficient design of ship hull forms based on intelligent optimization techniques. We discuss different methods involved in the optimization procedure, especially the latest developments of intelligent optimization algorithms and surrogate models. Moreover, current development trends and technical challenges of multidisciplinary design optimization and surrogate-assisted evolutionary algorithms for ship design are further analyzed. We explore the gaps and potential future directions, so as to paving the way towards the design of the next generation of more energy-efficient ship hull form.Comment: 30 pages, 8 figure

Observer-Based Stabilization for Nonlinear Composite Systems with Similarity

This paper studies nonlinear composite large-scale systems with similarity, which contain time-varying interconnections. First, a kind of observer is presented for the systmes. Then, the observer-based controllers which are used to stabilize the large-scale systems are designed. It shows that similar structure can simplify the analysis and design of systems. Finally, the conclusion is applied to a disk-shaft system and the simulation shows that our method is effective

Fiscal incentives, competition, and investment in China

This paper explores how fiscal incentives offered to local governments in China affect investment rates in their jurisdictions. Theoretically, we build a simple fiscal competition model to establish the linkage between local fiscal incentives and expenditure policy and consequently, capital movement. The key prediction of the model, borne out by data from Chinese provinces spanning 2004–2013, is that an increase in the local corporate income tax-sharing ratio, which proxies fiscal incentives offered to local governments, motivates local governments to compete for capital investment through increased public expenditures. Our results contribute to the fiscal federalism literature by showing that local fiscal incentives significantly shape policy choices and local economic performance. In addition, by exploring fiscal incentives offered to local governments, we offer a novel explanation for the unusually high investment rate in China that has been sustained over a prolonged period of time

Mid- to Long-Term Outcomes of Cervical Disc Arthroplasty versus Anterior Cervical Discectomy and Fusion for Treatment of Symptomatic Cervical Disc Disease: A Systematic Review and Meta-Analysis of Eight Prospective Randomized Controlled Trials.

PURPOSE:This study aimed to investigate the mid- to long-term outcomes of cervical disc arthroplasty (CDA) versus anterior cervical discectomy and fusion (ACDF) for the treatment of 1-level or 2-level symptomatic cervical disc disease. METHODS:Medline, Embase, and the Cochrane Central Register of Controlled Trials databases were searched to identify relevant randomized controlled trials that reported mid- to long-term outcomes (at least 48 months) of CDA versus ACDF. All data were analyzed by Review Manager 5.3 software. The relative risk (RR) and 95% confidence intervals (CIs) were calculated for dichotomous variables. The weighted mean difference (WMD) and 95%CIs were calculated for continuous variables. A random effect model was used for heterogeneous data; otherwise, a fixed effect model was used. RESULTS:Eight prospective randomized controlled trials (RCTs) were retrieved in this meta-analysis, including 1317 and 1051 patients in CDA and ACDF groups, respectively. Patients after an ACDF had a significantly lower rate of follow-up than that after CDA. Pooled analysis showed patients in CDA group achieved significantly higher rates of overall success, Neck Disability Index (NDI) success, neurological success and significantly lower rates of implant/surgery-related serious adverse events and secondary procedure compared with that in ACDF group. The long-term functional outcomes (NDI, Visual Analog Scale (VAS) neck and arm pain scores, the Short Form 36 Health Survey physical component score (SF-36 PCS)), patient satisfaction and recommendation, and the incidence of superior adjacent segment degeneration also favored patients in CDA group with statistical difference. Regarding inferior adjacent segment degeneration, patients in CDA group had a lower rate without statistical significance. CONCLUSIONS:This meta-analysis showed that cervical disc arthroplasty was superior over anterior discectomy and fusion for the treatment of symptomatic cervical disc disease in terms of overall success, NDI success, neurological success, implant/surgery-related serious adverse events, secondary procedure, functional outcomes, patient satisfaction and recommendation, and superior adjacent segment degeneration

Study of the allocation strategy of water pollutant emission permits under a bidirectional ecological compensation mechanism

Water pollutant emission permits (WPEPs) allocation is a competing limited consumption resource designed to address the issue of reconciling water pollution with economic development. In the wake of increasing conflicts, a pressing challenge is how to motivate stakeholders associated with the basin to establish a balance between economic development and environmental preservation. Based on the unidirectional flow of basin pollution, this study established a bidirectional ecological compensation (BEC) mechanism, which incorporated the key water pollution indicators (WPEPs allocation volume) into the BEC mechanism. By integrating the BEC mechanism with the WPEPs allocation model, a multi-objective optimization framework for balancing the fairness and economic efficiency of WPEPs allocation under the BEC synergy mechanism has been proposed. The Tuojiang river basin in China was selected for the study, and the allocation results and ecological compensation mechanisms under different allocation preferences were analyzed to verify the validity and practicality of the model. Results revealed that (1) BEC mechanisms can be considered to ensure equitable and efficient allocation of WPEPs in the basin. (2) Under the perspective of watershed cooperation, the bidirectional compensation mechanism proves to be an effective measure to promote economic development and environmental protection of the watershed. (3) Preferences of watershed managers for allocation and ecological compensation mechanisms can have an impact on the outcomes of allocation and ecological compensation mechanisms. This study provides reference for effective management and adoption of optimal allocation strategy of watershed WPEPs and synergistic management of BEC mechanisms

Forest plot for secondary procedure.

<p>Forest plot for secondary procedure.</p

Subgroup analysis of patients with 1-level cervical disc disease.

<p>Subgroup analysis of patients with 1-level cervical disc disease.</p

Forest plot for radiological adjacent segment degeneration.

<p>Forest plot for radiological adjacent segment degeneration.</p

Forest plot for neurological success and implant/surgery-related serious adverse events.

<p>Forest plot for neurological success and implant/surgery-related serious adverse events.</p

Characteristics of all included studies.

<p>Characteristics of all included studies.</p