融合Dead-ends和离线监督Actor-Critic的动态治疗策略生成模型

强化学习对数学模型依赖性低,利用经验便于架构和优化模型,非常适合用于动态治疗策略学习。但现有研究仍存在以下问题:1)学习策略最优性的同时未考虑风险,导致学到的策略存在一定的风险;2)忽略了分布偏移问题,导致学到的策略与医生策略完全不同;3)忽略患者的历史观测数据和治疗史,从而不能很好地得到患者状态,进而导致不能学到最优策略。基于此,提出了融合Dead-ends和离线监督Actor-Critic的动态治疗策略生成模型DOSAC-DTR。首先,考虑学到的策略所推荐的治疗行动的风险性,在Actor-Critic框架中融入Dead-ends概念;其次,为缓解分布偏移问题,在Actor-Critic框架中融入医生监督,在最大化预期回报的同时,最小化所学策略与医生策略之间的差距;最后,为了得到包含患者关键历史信息的状态表示,使用基于LSTM的编码器解码器模型对患者的历史观测数据和治疗史进行建模。实验结果表明,DOSAC-DTR相比基线方法有更好的性能,可以得到更低的估计死亡率以及更高的Jaccard系数。

The impact of heterogeneity and pore network characteristics on single and multi-phase fluid propagation in complex porous media:An X-ray computed tomography study

This study investigates the impact of pore network characteristics on fluid flow through complex and heterogeneous porous media,providing insights into the factors affecting fluid propagation in such systems.Specifically,high-resolution or micro X-ray computed tomography(CT)imaging techniques were utilized to examine outcrop stromatolite samples of the Lagoa Salgada,considered flow analogous to the Brazilian Pre-salt carbonate reservoirs.The petrophysical results comprised two distinct stromatolite depositional facies,the columnar and the fine-grained facies.By generating pore network model(PNM),the study quantified the relationship between key features of the porous system,including pore and throat radius,throat length,coordination number,shape factor,and pore volume.The study found that the less dense pore network of the columnar sample is typically characterized by larger pores and wider and longer throats but with a weaker connection of throats to pores.Both facies exhibited less variability in the radius of the pores and throats in comparison to throat length.Additionally,a series of core flooding experiments coupled with medical CT scanning was designed and conducted in the plug samples to assess flow propagation and saturation fields.The study revealed that the heterogeneity and presence of disconnected or dead-end pores significantly impacted the flow patterns and saturation.Two-phase flow patterns and oil saturation distribution reveal a preferential and heterogeneous displacement that mainly swept displaced fluid in some regions of plugs and bypassed it in others.The relation between saturation profiles,porosity profiles,and the number of fluid flow patterns for the samples was evident.Only for the columnar plug sample was the enhancement in recovery factor after shifting to lower salinity water injection(SB)observed.

Characteristics of Dynamic Load Response of a Fuel Cell with a Dead-ended Anode

The dynamic load characteristics of a proton exchange membrane fuel cell（PEMFC） with a dead-ended anode were studied. In a 70 h experiment, the effects of anode pressure, operating temperature, and relative humidity of the cathode on the performances of the fuel cell were investigated. The obtained results show that, with different relative humidity of the cathode at 65 ℃, dynamic loading has little effect on the performances of fuel cell and the electrochemically active surface area（ECSA）. However, the fuel cell operating under dynamic load is unstable when the relative humidity is 50%, and at 50 ℃ with 100% relative humidity, applying a dynamic load has a significant influence on the fuel cell performances. Scanning electron microscopy（SEM） showed that both the upstream and middle catalyst layers of the cell were unchanged, whereas the downstream cathode catalyst layer thinned as a response to dynamic load.

DPM simulation in an underground entry: Comparison between particle and species models

The diesel particulate matter(DPM) emission from diesel powered equipment in underground mines can cause health hazards including cancer to the miners. The understanding of the DPM propagation pattern under realistic mining condition is required for selecting proper DPM control strategies and to improve working practices in underground mines. In this paper, three dimensional simulations of DPM emission from the exhaust tail pipe of a load-haul-dump(LHD) vehicle and its subsequent distribution inside an isolated zone in the typical underground mine are carried out using two different solution models available in Ansys Fluent. The incoming fresh air into the isolated zone is treated as a continuous phase and DPM is treated either as a continuous phase(gas) or as a secondary discrete phase(particle). Species transport model is used when DPM is treated as gas and discrete phase model is used when DPM is assumed to behave like a particle. The distributions of DPM concentration inside the isolated zone obtained from each method are presented and compared. From the comparison results, an accurate and economical solution technique for DPM evaluation can be selected.

SME： The Hungarian Experience Situation and Development in Hungary

This paper aims to present the development of the SME sector through the example of a country in East-Central Europe. This country was once a member of the so-called communist block until 1989, but had a market economy in 1989. Hungary joined the EU on May 1, 2004, and displaied numerous interesting features concerning small and medium sized enterprises ever since, complying with a variety of expectations. The research study investigated the East-Central European SME systems, and particularly the Hungarian SME practice. The main methods used in this paper are present European and Hungarian research findings of nternational relevance. Several data and figures from the European Union, the Central European area and of course from Hungary were used for the characterization of the SME systems. The main results of the research study is a set of characteristics of the SMEs＇ East-Central European pathway： （1） SMEs as a pillar of the nation in the world and in Hungary; （2） Hungary as the Paradise of small enterprises （numbers versus reality）; （3） Domestic small enterprises in an international （European） comparison; （4） How the crisis impacted the domestic SME sector; （5） Misconceptions and dead ends in small enterprises today： What should the state subsidise and how？

Physical Modelling of the Drained Flow on a Suction Box of a Papermachine

Suction boxes are used in the paper industry to simultaneously drain a pulp suspension and form a fibre mat （or filter cake）. This research addresses the modelling of fibre deposition in the forming unit of an industrial papermachine, assuming a filtration process, and that of the flowing suspension drained through the building fibre mat and the wire on a suction box. From experimental data of the cumulative drained V volume, per unit surface area, for two vacuum pressures △P and 6 dwell times t, an extension of the classical law （t/V） versus V is proposed, validated and applied. This relation enables determining the average specific filtration resistance of the fibre mat over the box and the mass of solids deposited before and over the suction box. The model obtained is as precise as 1% and can be used to limit and reduce the energy consumption of drainage vacuum assisted devices such as suction boxes in the forming unit of industrial papermachines.

A non-uniform quadtree map building method including dead-end semantics extraction

To reduce the complexity of large-scene high-resolution maps while using the dead-end information distributed in the unmanned vehicle driving environment,we propose a novel non-uniform quadtree map-building method including dead-end semantic information extraction.By utilizing quadtree data structures,submaps and a positive-order tree depth organization approach,our proposed map can adapt to the large-scale high-resolution requirement and expand more easily to larger environments.To verify the practicality of our proposed map,we have successfully implemented map matching and path planning in real environments.Additionally,we effectively extract the dead-end semantic information that widely distributes in the environment,which can help unmanned vehicles avoid collisions and improve the search efficiency of the planning procedure.We evaluate our method with KITTI datasets,CARLA Simulator,and our self-collected real-world datasets.The experimental results show that our proposed method significantly reduces the complexity of large-scale high-resolution maps,effectively extracts dead-end semantic information,and has good practicality in real environments.The implementation of our method is released here:https://github.com/biter0088/Non-uniform-quadtree-map.

Integrating ancient patterns and current dynamics of insect-plant interactions＂ Taxonomic and geographic variation in herbivore specialization

The search for pattern in the ecology and evolutionary biology of insect-plant associations has fascinated biologists for centuries. High levels of tropical （tow-latitude） plant and insect diversity relative to poleward latitudes and the disproportionate abundance of host-specialized insect herbivores have been noted. This review addresses several aspects of local insect specialization, host use abilities （and loss of these abilities with specialization）, host-associated evolutionary divergence, and ecological （including ＂hybrid＂） speciation, with special reference to the generation of biodiversity and the geographic and taxonomic identification of ＂species borders＂ for swallowtail butterflies （Papilionidae）. From ancient phytochemically defined angiosperm affiliations that trace back millions of years to recent and very local specialized populations, the Papilionidae （swallowtail butterflies） have provided a model for enhanced tmderstanding of localized ecological patterns and genetically based evolutionary processes. They have served as a useful group for evaluating the feeding specialization/physiological efficiency hypothesis. They have shown how the abiotic （thermal） environment interacts with host nutritional suitability to generate ＂voltinisrn/suitability＂ gradients in specialization or preference latitudinally, and geographical mosaics locally. Several studies reviewed here suggest strongly that the oscillation hypothesis for speciation does have considerable merit, but at the same time, some species-level host specializations may lead to evolutionary dead-ends, especially with rapid environmental/habitat changes involving their host plants. Latitudinal gradients in species richness and degree of herbivore feeding specialization have been impacted by recent developments in ecological genetics and evolutionary ecology. Localized insect- plant associations that span the biospectrum from polyphenisms, polymorphisms, biotypes, demes, host races, to cryptic species, remain academically contentious, with simple definitions still debated. However, molecular analyses combined with ecological, ethological and physiological studies, have already begun to unveil some answers for many important ecological/evolutionary questions.