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An innovative heterogeneous transfer learning framework to enhance the scalability of deep reinforcement learning controllers in buildings with integrated energy systems

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building Simulation 2024年第5期17卷 739-770页

作者： Davide Coraci Silvio Brandi Tianzhen Hong Alfonso Capozzoli Politecnico di Torino Department of EnergyTEBE research groupBAEDA Lab.Corso Duca degli Abruzzi 24Torino10129Italy building technology and urban systems division Lawrence Berkeley National LaboratoryOne Cyclotron RoadBerkeleyCA 94720USA

Deep Reinforcement Learning(DRL)-based control shows enhanced performance in the management of integrated energy systems when compared with Rule-Based Controllers(RBCs),but it still lacks scalability and generalisation due to the necessity of using tailored models for the training process.Transfer Learning(TL)is a potential solution to address this limitation.However,existing TL applications in building control have been mostly tested among buildings with similar features,not addressing the need to scale up advanced control in real-world scenarios with diverse energy systems.This paper assesses the performance of an online heterogeneous TL strategy,comparing it with RBC and offline and online DRL controllers in a simulation setup using EnergyPlus and Python.The study tests the transfer in both transductive and inductive settings of a DRL policy designed to manage a chiller coupled with a Thermal Energy Storage(TES).The control policy is pre-trained on a source building and transferred to various target buildings characterised by an integrated energy system including photovoltaic and battery energy storage systems,different building envelope features,occupancy schedule and boundary conditions(e.g.,weather and price signal).The TL approach incorporates model slicing,imitation learning and fine-tuning to handle diverse state spaces and reward functions between source and target buildings.Results show that the proposed methodology leads to a reduction of 10% in electricity cost and between 10% and 40% in the mean value of the daily average temperature violation rate compared to RBC and online DRL controllers.Moreover,online TL maximises self-sufficiency and self-consumption by 9% and 11% with respect to RBC.Conversely,online TL achieves worse performance compared to offline DRL in either transductive or inductive settings.However,offline Deep Reinforcement Learning(DRL)agents should be trained at least for 15 episodes to reach the same level of performance as the online TL.Therefore,the proposed online TL methodology

关键词： transfer learning reinforcement learning building control building energy management

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Heat Storage Performance of PCM in a Novel Vertical Pointer-Shaped Finned Latent Heat Tank

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Journal of Thermal Science 2024年第2期33卷 422-434页

作者： MAO Qianjun ZHU Yuanyuan LI Tao School of urban Construction Wuhan University of Science and TechnologyWuhan430065China

The heat storage performance of latent heat storage systems is not good due to the poor thermal conductivity of phase change materials.In this paper,a new type of pointer-shaped fins combining rectangular and triangular fins has been employed to numerically simulate the melting process in the heat storage tank,and the fin geometry parameter effects on heat storage performance have been studied.The results indicate that compared with the bare tube and the rectangular finned tank,the melting time of the phase change material in the pointer-shaped finned tank is reduced by 64.2%and 15.1%,respectively.The closer the tip of the triangular fin is to the hot wall,the better the heat transfer efficiency.The optimal height of the triangular fin is about 8 mm.Increasing the number of fins from 4 to 6 and from 6 to 8 reduces the melting time by 16.0%and 16.7%respectively.However,increasing the number of fins from 8 to 10 only reduces the melting time by 8.4%.When the fin dimensionless length is increased from 0.3 to 0.5 and from 0.5 to 0.7,the melting time is shortened by 17.5%and 13.0%.But the melting time is only reduced by 2.9%when the dimensionless fin length is increased from 0.7 to 0.9.For optimising the design of the thermal storage system,the results can provide a reference value.

关键词： thermal energy storage phase change material pointer-shaped fins heat storage performance

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Precise control of page cache for containers

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Frontiers of Computer Science 2024年第2期18卷 17-30页

作者： Kun WANG Song WU Shengbang LI Zhuo HUANG Hao FAN Chen YU Hai JIN National Engineering Research Center for Big Data technology and system Services Computing Technology and System LabCluster and Grid Computing Lab School of Computer Science and TechnologyHuazhong University of Science and TechnologyWuhan 430074China

Container-based virtualization isbecoming increasingly popular in cloud computing due to its efficiency and flexibility.Resource isolation is a fundamental property of containers.Existing works have indicated weak resource isolation could cause significant performance degradation for containerized applications and enhanced resource isolation.However,current studies have almost not discussed the isolation problems of page cache which is a key resource for containers.Containers leverage memory cgroup to control page cache usage.Unfortunately,existing policy introduces two major problems in a container-based environment.First,containers can utilize more memory than limited by their cgroup,effectively breaking memory isolation.Second,the Os kernel has to evict page cache to make space for newly-arrived memory requests,slowing down containerized applications.This paper performs an empirical study of these problems and demonstrates the performance impacts on containerized applications.Then we propose pCache(precise control of page cache)to address the problems by dividing page cache into private and shared and controlling both kinds of page cache separately and precisely.To do so,pCache leverages two new technologies:fair account(f-account)and evict on demand(EoD).F-account splits the shared page cache charging based on per-container share to prevent containers from using memory for free,enhancing memory isolation.And EoD reduces unnecessary page cache evictions to avoid the performance impacts.The evaluation results demonstrate that our system can effectively enhance memory isolation for containers and achieve substantial performance improvement over the original page cache management policy.

关键词： page cache memory cgroup container isolation cloud computing

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urban Flood Mitigation Strategies with Coupled Gray–Green Measures: A Case Study in Guangzhou City, China

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International Journal of Disaster Risk Science 2024年第3期15卷 467-479页

作者： Jiayue Li Jiajun Zeng Guoru Huang Wenjie Chen School of Civil Engineering and Transportation South China University of Technology School of Architecture South China University of Technology State Key Laboratory of Subtropical building and urban Science South China University of Technology College of Water Conservancy and Civil Engineering South China Agricultural University

The integration of gray and green infrastructure has proven to be a feasible approach for managing stormwater in established urban areas. However, evaluating the specific contributions of such coupled strategies is challenging. This study introduced a novel integrated hydrological-hydrodynamic model that takes into account the layout of low-impact development(LID)facilities along with pipeline alignment and rehabilitation. Reliable results from modeling were used to assess the individual contribution of LID and improved drainage facilities to urban flooding mitigation. We selected a natural island in Guangzhou City, China, as the study site. The results indicate that combining three LID measures, namely green roofs, sunken green spaces, and permeable pavements, can reduce total runoff by 41.7% to 25.89% for rainfall recurrence periods ranging from 1year to 100 years, and decrease the volume of nodal overflow by nearly half during rainfall events of less than 10-year return period. By integrating LID measures with the upgraded gray infrastructure, the regional pipeline overloading condition is substantially alleviated, resulting in a significant improvement in pipeline system resilience. For urban flooding control, it is recommended to integrate sufficient green space and avoid pipe-laying structural issues during urban planning and construction. The findings may assist stakeholders in developing strategies to best utilize gray and green infrastructure in mitigating the negative eff ects of urban flooding.

关键词： Coupled hydrodynamic model Gray–green approach Guangzhou City LID Pipe renovation urban inundation

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Polystyrene nanoplastics induce glycolipid metabolism disorder via NF-κB and MAPK signaling pathway in mice

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Journal of Environmental Sciences 2024年第3期137卷 553-566页

作者： Xingpei Fan Xiaoyan Li Jiaxin Li Yuxia Zhang Xiangjuan Wei Hailong Hu Boya Zhang Haining Du Meimei Zhao Ruijiao Zhu Daqian Yang Yuri Oh Ning Gu School of Life Science and technology Harbin Institute of TechnologyHarbin 150001China State Key Laboratory of urban Water Resource and Environment Harbin Institute of TechnologyHarbin 150006China Department of Medicine Renal Electrolyte and Hypertension DivisionDepartment of GeneticsPerelman School of MedicineUniversity of PennsylvaniaPhiladelphia 19104USA Faculty of Education Wakayama UniversityWakayama 640-8441Japan

Nanoplastics-induced developmental and reproductive toxicity,neurotoxicity and immunotoxicity are a focus of widespread attention.However,the effects of nanoplastics(NPs)on glycolipid metabolism and the precise underlying mechanisms are unclear at present.Here,we showed that oral administration of polystyrene nanoparticles(PS-NPs)disrupts glycolipid metabolism,with reactive oxygen species(ROS)identified as a potential key signaling molecule.After PS-NPs treatment,excessive production of ROS induced the infammatory response and activated the antioxidant pathway through nuclear factor-erythroid factor 2-related factor 2.The activation of nuclear factor-κB(NFκB)signaling pathway induced the phosphorylation of the mitogen-activated protein kinases(MAPK)signaling pathway,which induced the activation of extracellular regulated kinases(ERK)and p38.Constitutive activation of the MAPK signaling proteins induced high continued phosphorylation of insulin receptor substrate-1,in turn,leading to decreased protein kinase B(Akt)activity,which weakened the sensitivity of liver cells to insulin signals and induced insulin resistance.In parallel,phosphorylation of Akt led to loss of control of Fo XO1,a key gene of gluconeogenesis,activating transcription of glucose-6-phosphatase(G6PC)and phosphoenolpyruvate carboxykinase(PEPCK)in a manner dependent on PGC1α.Moreover,the activated ERK promoted lipid accumulation through ERK-PPARγcascades.Therefore,sterol regulatory element-binding protein-1 and levels of its downstream lipogenic enzymes,ACC-1,were up-regulated.Upon treatment with the antioxidant resveratrol,PS-NPs-induced glucose and lipid metabolic disorders were improved by inhibiting ROS-induced activation of NFκB and MAPK signaling pathway in mice.Based on above,PS-NPs exposure disrupts glycolipid metabolism in mice,with ROS identified as a potential key signaling molecule.

关键词： Nanoplastics Resveratrol Hyperglycemia Lipid metabolism Infammatory response Reactive oxygen species(ROS)

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Anticipating the lifespan: Predicting the durability of an anode-supported solid oxide fuel cell short stack over 50,000 h

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Progress in Natural Science:Materials International 2024年第3期34卷 606-613页

作者： Muhammad Zubair Khan Amjad Hussain Seung-Bok Lee Tak-Hyoung Lim Rak-Hyun Song Department of Materials Science & Engineering Pak-Austria Fachhochschule: Institute of Applied Sciences and Technology Mang Haripur Hydrogen Energy Research division Korea Institute of Energy Research Department of Advanced Energy and system Engineering Korea University of Science and Technology (UST)

In the present study, the operational lifetime of a solid oxide fuel(SOFC) short stack is predicted by investigating the performance degradation of both the short stack and its cells throughout 1000 h at 800°C. The short stack and integral cell voltages are continuously measured during the long-term test, with electrochemical impedance spectroscopy(EIS) conducted every 200 h. The short stack voltage decreased rapidly for the initial 200–300 h and afterwards, it decreased at a slow rate due to the increase in the Ohmic and polarization resistances in the same manner. Scanning electron microscopy results show that there is no delamination or cracking among constituent layers of the short-stack cells. The single degradation effects of the Ni coarsening in the anode, cation migration and surface segregation in cathode and oxide scale growth in metallic interconnect mesh are successfully integrated into a comprehensive lifetime prediction model. The experimentally measured voltage degradation data of the short stack fits well with the developed mathematical model and allows the successful prediction of the lifetime up to 50,000 h.

关键词： Degradation Impedance Lifetime SOFC Stack

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3D nano-printed geometric phase metasurfaces for generating accelerating beams with complex amplitude manipulation

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Science China(Physics,Mechanics & Astronomy) 2024年第6期67卷 86-95页

作者： Tianchen Tang Saima Kanwal Yongzheng Lu Yuelong Li Shuangbao Wu Lei Chen Ziheng Qian Zhouyu Xie Jing Wen Dawei Zhang Research Center of Optical Instrument and system Ministry of Education and Shanghai Key Lab of Modern Optical SystemUniversity of Shanghai for Science and TechnologyShanghai 200093China

Metasurface,a forefront in emerging optical devices,has demonstrated remarkable potential for complex amplitude manipulation of light beams.However,prevailing approaches face challenges in spatial resolution and complexities associated with integrating dynamic phases,impeding the simplified design and reproducible fabrication of metasurfaces.Here,we introduce an innovative approach for complex amplitude modulation within 3D nano-printed geometric phase metasurfaces.Our approach enables the generation of self-accelerating beams by encoding amplitude through phase-only manipulation,achieving high spatial resolution.Notably,this method circumvents the conventional need to adjust the geometric parameters of metasurface unit structures for amplitude manipulation,offering a streamlined and efficient route for design and fabrication complexity.This novel methodology holds promise for expedited and low-cost manufacturing of complex amplitude manipulation metasurfaces.

关键词： metasurface complex amplitude manipulation geometric phase 3D nano-printing Airy beam accelerating parabolic beam

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Security-constrained Transmission Maintenance Optimization Considering Generation and Operational Risk Costs

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Journal of Modern Power systems and Clean Energy 2024年第3期12卷 767-781页

作者： Dan Xu Zhi Cai Qian Cheng Guodong Huang Jingyang Zhou Junjie Tang Beijing Key Laboratory of Research and system Evaluation of Power Dispatching Automation technology China Electric Power Research Institute State Key Laboratory of Power Transmission Equipment & system Security and New technology Chongqing University

With the large-scale integration of renewable energy, the traditional maintenance arrangement during the load valley period cannot satisfy the transmission demand of renewable energy generation. Simultaneously, in a market-oriented operation mode, the power dispatching control center aims to reduce the overall power purchase cost while ensuring the security of the power system. Therefore, a security-constrained transmission maintenance optimization model considering generation and operational risk costs is proposed herein. This model is built on double-layer optimization framework, where the upper-layer model is used for maintenance and generation planning, and the lowerlayer model is primarily used to address the operational security risk arising from the random prediction error and N-1 transmission failure. Correspondingly, a generation-maintenance iterative algorithm based on a defined cost feedback is included to increase solution efficiency. Generation cost is determined using long-term security-constrained unit commitment, and the operational risk cost is obtained using a double-layer N-1 risk assessment model. An electrical correlation coupling coefficient is proposed for the solution process to avoid maintenance of associated equipment simultaneously, thereby improving model convergence efficiency. The IEEE 118-bus system is used as a test case for illustration, and test results suggest that the proposed model and algorithm can reduce the total cost of transmission maintenance and system operation while effectively improving the solution efficiency of the joint optimization model.

关键词： Maintenance engineering Costs Optimization Power systems Renewable energy sources Power grids Load modeling

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Performance assessment of prefabricated vertical drains in mitigating soil reliquefaction subjected to repeated seismic events using shaking table experiments

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Frontiers of Structural and Civil Engineering 2024年第3期18卷 411-427页

作者： Gowtham PADMANABHAN Ganesh Kumar SHANMUGAM Department of Earthquake Engineering Indian Institute of Technology RoorkeeUttarakhand 247667India Geotechnical Engineering division CSIR-Central building Research Institute Academy of Scientific and Innovative Research(AcSIR)Uttarakhand 247667India

The use of prefabricated vertical drains(PVD)in liquefiable deposits is gaining attention due to enhanced drainage.However,investigations on PVD in mitigating re-liquefaction during repeated shaking events are not available.This study performed a series of shaking table experiments on untreated and PVD-treated specimens prepared with 40%and 60%relative density.Repeated sinusoidal loading was applied with an incremental peak acceleration of 0.1g,0.2g,0.3g,and 0.4g,at 5 Hz shaking frequency with 40 s duration.The performance of treated ground was evaluated based on the generation and dissipation of excess pore water pressure(EPWP),induced sand densification,subsidence,and cyclic stress ratio.In addition,the strain accumulated in fresh and exhumed PVD was investigated using geotextile tensile testing apparatus aided with digital image correlation.No evidence of pore pressure was reported up to 0.2g peak acceleration for 40%and 60%relative density specimens.The continuous occurrence of soil densification and drainage medium restrained and delayed the generation of EPWP and expedited the dissipation process.This study demonstrates PVD can mitigate re-liquefaction,without suffering from deterioration,when subjected to medium to high intense repeated shaking events.

关键词： prefabricated vertical drains drainage re-liquefaction shaking table digital image correlation

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A hybrid memory architecture supporting fine-grained data migration

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Frontiers of Computer Science 2024年第2期18卷 31-41页

作者： Ye CHI Jianhui YUE Xiaofei LIAO Haikun LIU Hai JIN National Engineering Research Center for Big Data technology and system Services Computing Technology and System LabCluster and Grid Computing LabSchool of Computer Science and TechnologyHuazhong University of Science and TechnologyWuhan 430074China Department of Computer Science Michigan Technological UniversityMichigan 49931USA

Hybrid memory systems composed of dynamic random access memory(DRAM)and Non-volatile memory(NVM)often exploit page migration technologies to fully take the advantages of different memory media.Most previous proposals usually migrate data at a granularity of 4 KB pages,and thus waste memory bandwidth and DRAM resource.In this paper,we propose Mocha,a non-hierarchical architecture that organizes DRAM and NVM in a flat address space physically,but manages them in a cache/memory hierarchy.Since the commercial NVM device-Intel Optane DC Persistent Memory Modules(DCPMM)actually access the physical media at a granularity of 256 bytes(an Optane block),we manage the DRAM cache at the 256-byte size to adapt to this feature of Optane.This design not only enables fine-grained data migration and management for the DRAM cache,but also avoids write amplification for Intel Optane DCPMM.We also create an Indirect Address Cache(IAC)in Hybrid Memory Controller(HMC)and propose a reverse address mapping table in the DRAM to speed up address translation and cache replacement.Moreover,we exploit a utility-based caching mechanism to filter cold blocks in the NVM,and further improve the efficiency of the DRAM cache.We implement Mocha in an architectural simulator.Experimental results show that Mocha can improve application performance by 8.2%on average(up to 24.6%),reduce 6.9%energy consumption and 25.9%data migration traffic on average,compared with a typical hybrid memory architecture-HSCC.

关键词： non-volatile memory hybrid memory system data migration fine-grained caching

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