Typical Hierarchical Structure Research Articles

Whom Does Remote Work Make Happy? The Digital Divide in Remote Workers' Well-Being.

The global shift to remote work during the COVID-19 pandemic has intensified scholarly attention to remote workers' well-being. Although existing studies explore the varied impacts of remote work, there is a gap in understanding remote workers' well-being through the lenses of social disparity and the digital divide. Extending digital divide scholarship to the remote work context, this study disentangles why some remote workers experience better well-being than others. We conducted a two-wave longitudinal panel study in South Korea during the COVID-19 pandemic (Wave 1: February 2021, Wave 2: October 2021). Among the 501 participants who participated in both waves, we found that individuals with lower education levels were less likely to have remote work opportunities. We focused our further analyses on a subset of 144 employees who had remote work opportunities within organizations with typical hierarchical structures. We found that socioeconomic status (SES) did not directly influence remote workers' well-being but indirectly influenced it by contributing to the diversity in using information and communication technologies (ICTs). Workers with higher SES or more diversity in using ICTs demonstrated lower vulnerability and more effectiveness in maintaining their well-being in virtual organizational communication situations. This study highlights social disparities in remote workers' well-being, which arise from the complex interplay of SES either indirectly influencing the diversity in ICT usage or interacting with virtual organizational communication satisfaction and duration. This study advances remote work scholarship by restructuring theoretical discussions on social stratification and the digital divide reproduced within the evolving work environment.

Facile exfoliation of natural silk nanofibrils for homogeneous reinforced composites

AbstractRegenerated silk fibroin (SF) as a biomaterial has attracted increasing attention due to its outstanding biocompatibility and processibility. However, it faces great challenges in practical application because of the deterioration of the intrinsic mechanical properties of natural silk during the regeneration process. Natural silk nanofibrils (SNFs) has a typical hierarchical structure and maintains excellent mechanical properties of natural silk. Based on principle of homogeneous reinforced composites, herein, the SNFs were isolated as a reinforcing material and regenerated SF as matrix material to fabricate high‐performance SF nanocomposites. The SNFs with diameters ranging from 100 to 600 nm were prepared with yields of 87%. They not only maintained the crystallinity of natural silk, but also remained high stability in acid and alkaline solutions. Thanks to homogenous reinforcement of the SNFs, the tensile stress of the reinforced film was up to 2.2 MPa, the strain was 129%, and the water absorption was 50% in wet state. In vitro, the reinforced films supported adhesion and proliferation of human umbilical vein endothelial cells, which has potential in the application of biomedical dressings.Highlights Natural silk nanofibrils (SNFs) were exfoliated using a facile approach. The SNFs reinforced the silk nanocomposites significantly. The silk nanocomposites showed remarkable cytocompatibility. Homogeneous reinforcement is useful strategy to fabricate nanocomposites.

체계기능언어학의 주기어 위계 연구

Objectives The purpose of this study is to explicitly show how the hierarchy of periodicity in Korean texts is ana-lyzed based on Systemic Functional Linguistics.
 Methods The hierarchy of periodicity is viewed as having an expanding structure, like the flow of water, which expands into small waves, large waves, and tidal waves. It is explained that when the flow of text expands from clause to paragraph (→ chapter → text), it does not continue in a straight line, but expands like a wave in a circle. Assuming that this hierarchy of periodicity has genre differences, this paper analyzed the text of political news-paper articles related to the ‘Itaewon tragedy’ in written language and the text of parliamentary meeting related to the ‘Itaewon tragedy’ in spoken language.
 Results In terms of the hierarchical structure of the periodical, the newspaper article and the meeting showed different characteristics. The newspaper article (Text-I) was relatively well organized and followed the typical hi-erarchical structure of a periodical. In particular, it showed that it faithfully followed the structure of HyperTheme - (Elaboration) - HyperNew, which is necessary to organize paragraphs (paragraphs). It also followed the structure of MacroTheme - (Paragraph) - MacroNew when organizing units larger than paragraphs. The meeting text, on the other hand, shows a weak hierarchy, as the MacroTheme is sometimes omitted, and when organizing para-graphs, the HyperNew following the HyperTheme is omitted before moving on to the next topic, the MacroTheme.
 Conclusions This paper introduced the concepts of hierarchy of periodic words and serial word expansion of dis-course as two double-headed wagons for studying discourse meaning. I hope this article to be useful for future research on periodicity in Korean texts of various genres, as it demonstrates how to analyze discourse at the para-graph and text level beyond the analysis of ‘clause’ units, and examines the genre differences between them.

HPRE: Leveraging hierarchy-aware paired relation vectors for knowledge graph embedding

Knowledge graphs exhibit a typical hierarchical structure and find extensive applications in various artificial intelligence domains. However, large-scale knowledge graphs need to be completed, which limits the performance of knowledge graphs in downstream tasks. Knowledge graph embedding methods have emerged as a primary solution to enhance knowledge graph completeness. These methods aim to represent entities and relations as low-dimensional vectors, focusing on handling relation patterns and multi-relation types. Researchers need to pay more attention to the crucial feature of hierarchical relationships in real-world knowledge graphs. We propose a novel knowledge graph embedding model called Hierarchy-Aware Paired Relation Vectors Knowledge Graph Embedding (HPRE) to bridge this gap. By leveraging the power of 2D coordinates, HPRE adeptly model relation patterns, multi-relation types, and hierarchical features in the knowledge graph. Specifically, HPRE employs paired relation vectors to capture the distinct characteristics of head and tail entities, facilitating a better fit for relational patterns and multi-relation scenarios. Additionally, HPRE employs angular coordinates to differentiate entities at various levels of the hierarchy, effectively representing the hierarchical nature of the knowledge graph. The experimental results show that the HPRE model can effectively learn the hierarchical features of the knowledge graph and achieve state-of-the-art experimental results on multiple real-world datasets for the link prediction task.

Performance and mechanism of hierarchical porous Al2O3-MgO nanosheets for removing fluoride ions from industrial ZnSO4 solution

Excessive concentration of fluoride ion (F-) in ZnSO4 solution will cause serious harm to zinc electrowinning. Therefore, it is necessary to defluorinate the ZnSO4 solution to reduce the concentration of F- to below 50 mg·L-1 to ensure the smooth progress of subsequent production. In this study, Al2O3-MgO nanosheets (HP-AMO-NTs) with typical hierarchical porous structure were prepared by hydrothermal-roasting method. The synthesized HP-AMO-NTs were characterized by XRD, SEM-EDS, BET, FT-IR and XPS. In order to evaluate the performance of HP-AMO-NTs for F- removal, we studied various factors affecting F- adsorption. When the F- concentration decreased to a reasonable range (<50 mg·L-1), the optimal removal percentage and adsorption capacity were 65.80% and 9.13 mg·g−1, respectively. The correlation coefficient of Pseudo-second-order kinetic model and Langmuir adsorption isotherm model was the highest. According to thermodynamic analysis, the adsorption and defluoridation of HP-AMO-NTs was a spontaneous, exothermic and entropy-reducing reaction. SEM-EDS analysis showed that a large amount of fluorine entered into HP-AMO-NTs after adsorption. FT-IR and XPS analysis showed that F- was ion-exchanged with hydroxyl (–OH) adsorption active groups and coordinated to form Mg/Al-F complexes to achieve removal from ZnSO4 solution. The theoretical maximum adsorption capacity of HP-AMO-NTs is 10.73 mg·g−1, indicating that HP-AMO-NTs is a potential efficient adsorbent for removing F- from industrial ZnSO4 solution. This provides a new idea for the development of high-performance ZnSO4 solution defluorination materials.

New insight into efficient photocatalytic CO2 reduction without any sacrifice agent over the novel hierarchical structured SiOC whisker aerogel

Photoreduction of CO2 to valuable fuels provides a promising strategy for managing the global carbon balance using renewable solar energy, yet the design of active, cost-effective, highly selective, and stable CO2 reduction photocatalysts remains a big challenge. Herein, we report a novel SiOC aerogel photocatalyst synthesized by a simple one-step sol-gel process, combined with the supercritical drying technique and heat treatment processes. The resulting SiOC aerogel exhibits a large BET specific area with typical hierarchical structures, which is responsible for the enhanced photocatalytic activity. In addition, the formation mechanism of the SiOC whisker aerogel is revealed in this study. The optimized SiOC aerogel exhibits CH4 and CO evolution activity of 5.8 and 20.5 μmol/g under simulated sunlight irradiation, respectively, without any additional co-catalyst or sacrificial agent, which is 6.4 and 3.9 times higher than those of the pristine SiC aerogel. The density functional theory (DFT) calculation confirms that the resulting SiOC aerogel can effectively adsorb and activate CO2 and H2O molecules on the catalyst surface. The Gibbs free energy diagram further verifies the superior performance of the resulting SiOC aerogel over the pristine SiC and SiO2 cluster via the rate-determining step calculations. The high efficiency of CO2 reduction can be attributed to the structural merits and the electronic structures modulation, which greatly achieves fast separation and transfer of charge carriers. The work paves an insight into the rational design of photocatalysts toward simultaneously facilitating carrier separation and CO2 activation from aerogel-based porous materials.

Simulation study on the anti-penetration performance and energy absorption characteristics of honeycomb aluminum sandwich structure

This work studied the anti-penetration performance and energy absorption characteristics of the honeycomb aluminum core structure. Tests of penetrating depth were conducted. The response and deformation resistance of the aluminum sandwich structure with a regular hexagonal honeycomb were studied through numerical simulation. The effect of the face/back plate thickness ratio and the shape of the core layer unit on the performance of the aluminum sandwich structure with a regular hexagonal honeycomb were compared and analyzed with a theoretical model of equivalent target calculation. Based on the results, the aluminum sandwich structure with a regular hexagonal honeycomb has the strongest anti-penetration capability when the thickness ratio of the face/back plate is set to 2.5:1. In terms of the energy consumption, the Arrow and concave hexagonal honeycomb aluminum sandwich structures are 14.7% and 25.9%, respectively, than the aluminum sandwich structure with a regular hexagonal honeycomb. The typical hierarchical honeycomb aluminum sandwich structure has better energy absorption characteristics than the aluminum sandwich structure with a regular hexagonal honeycomb. Therefore, the anti-penetration performance of the honeycomb aluminum sandwich structure can be improved by adjusting the thickness ratio of the face/back plate and changing the shape of the core layer. The research results are of great significance in guiding the design of the honeycomb aluminum sandwich structure.

One-step electrodeposition of Ni-Mo electrode with column-pyramid hierarchical structure for highly-efficient hydrogen evolution

The construction of transition metal alloys with 3D structure facilitates their catalytic activity towards hydrogen evolution reaction. Although this can be achieved by the wet chemical and template strategies, the uncertainty of reaction process inevitably results in the difficulty of the repeatability of product synthesis. Herein, we present the rationally designed 3D Ni-Mo with a typical hierarchical structure on Ni foam by combing ‘hydrogen bubble template’ and ‘tip effect’ via one-step electrodeposition. This 3D Ni-Mo/NF has both regular columnar structures of micron level and widespread pyramidal-like nanoparticles, which only needs an overpotential of 53 mV and 161 mV to afford 10 mA cm−2 and 100 mA cm−2 for HER in 1 M KOH, respectively. In addition, a small Tafel slope (42.6 mV dec-1), and long-term operational stability are achieved on the catalyst. The excellent performance can be traced to the amorphous and hierarchical structure with favorable active sites. Furthermore, the network structure of the nickel foam substrate can promote the diffusion and infiltration of electrolyte. Impressively, this electrode exhibits super hydrophilic, which facilitates the detachment of bubbles. The free-standing 3D catalysts in this study can be synthesized in a facile and viable way, indicating their promising tactic for scaled-up water electrolysis.

New Design and Construction of Hierarchical Porous Ni/SiO2 Catalyst with Anti‐sintering and Carbon Deposition Ability for Dry Reforming of Methane

AbstractRecently, low‐resistance to sintering and carbon deposition used in dry reforming of methane (DRM) limits their industrial application. In this study, we synthesized the better anti‐carbon deposition performance of a novel Ni/SiO2 catalyst which has hierarchical porous flower‐like structure by hydrothermal method. A series of characterizations were carried out by different test methods, and the results confirmed that the material had typical hierarchical porous structure, high specific surface areas, and strong metal‐support interaction. The catalyst activity tests at 700 °C in 40 h reaction manifested that CO2 and CH4 conversions of the flower‐like structure of Ni/SiO2 (F‐Ni/SiO2) (87.44% and 79.56%) are higher than that of Ni/SiO2 by the conventional impregnation method (C‐Ni/SiO2) (71.79% and 62.30%). The main reasons can be explained that the large specific surface area, Ni particles were well dispersed on the support surface, and the interaction between the active metal and support of the flower‐like structure of F‐Ni/SiO2 catalyst, have better stability and catalytic performance. Meanwhile, the TG result also showed that the F‐Ni/SiO2 catalyst had better anti‐carbon deposition performance than the traditional catalyst, which leading to a higher catalytic activity.

Aluminum borate whisker-based lattices with a hierarchical pore structure obtained via digital light processing

To satisfy the ever-increasing demand for aluminum borate porous ceramics with complex shapes and tunable pore structures in a diverse set of fields, aluminum borate whisker-based lattices with hierarchical pore structures were fabricated by a combination of in situ reaction and digital light processing three-dimensional (3D) printing. The optimal dispersant concentration and exposure parameters for 3D printing were determined based on analyses of the rheological properties and working curves of the Al2O3–B2O3 photosensitive slurries. The effects of the B2O3/Al2O3 molar ratio on the morphology and properties of aluminum borate lattices were investigated. The results showed that the addition of an excess of B2O3 was beneficial to the growth of aluminum borate whiskers. When the B2O3/Al2O3 molar ratio was set to 6:9, the resultant aluminum borate lattices exhibited a typical hierarchical pore structure, including inherent large pores in the lattices and small pores formed by interlocked aluminum borate whiskers generated in situ within the struts. This unique hierarchical pore structure endowed the ceramic lattices with a high compressive strength (1.18 MPa) and porosity (82.58%), as well as non-brittle fracture characteristics. Owing to these outstanding properties, aluminum borate whisker-based lattices are promising candidates for high-temperature thermal insulation, catalyst supports, acoustic absorption, and particle filtration.

Atomic study on deformation behaviors of crystal-glass nanocomposite with a typical hierarchical structure

The deformation behaviors of crystal-glass nanocomposites with structural heterogeneities that contain different grain sizes in their crystal phase are studied by using molecular dynamics simulation. Their stress–strain response and microstructures evolved with the applied tensile strain are quantitively analyzed. It is found that the mechanical response of the nanocomposite is sensitive to the average grain size of its crystal phase, and the specimen with the smallest grain size exhibits the highest strength among all. Strain partitioning inevitably occurs between the crystal phase and the glassy domains during the tensile loading, while the average atomic shear strain of the glassy phase is increased with the grain size of the crystal phase. As well, the increased grain size also aggravates the strain localization inside the glassy domains, which promotes the formation of shear transformation zones (STZs) and facilitates the strain heterogeneities there. A mass of lath-like stain paths with severe strain localization are also observed to form in the nanocomposite specimen with a larger grain size, which can function as the transmission medium for delivering the shear strains between different domains and accommodating the plastic flows during the deformation. The present work is aimed to underline that the configuration of structural heterogeneities in the glass-crystal nanocomposite can alter the strain partitioning between different phase domains, which can be used to tune the mechanical performance of the nanocomposite. The unveiled atomistic deformation mechanism of the crystal-glass nanocomposite also provide new sights on designing and optimizing the structural heterogeneities of nanocomposites for achieving better mechanical properties in future.

Fabrication of 316L nuclear nozzles on the main pipeline with large curvature by CMT wire arc additive manufacturing and self-developed slicing algorithm

A feasibility research was firstly carried out to deposit SS316L nuclear nozzles directly on the large-curvature PWR (pressurized water reactor) main pipeline by using the well-designed spatial scanning path derived from self-developed slicing algorithm for 3D model during wire arc additive manufacturing (WAAM) and CMT (cold metal transfer) process. This study provides comprehensive and systematic microstructure and mechanical datum of the as-deposited WAAM-CMT SS316L nozzles. Microstructure characterizations indicate that almost no precipitates or hot crack except micron pores remain inside, and the molten pools present typical hierarchical structures: 1.26% granular-δ within cellular γ sub-grains in the bottom region, lathy-δ within cellular γ grains in the central region and 6.49% skeletal-δ within column dendritic γ grains in the top region, respectively. This can be attributed to the synergistic effects of temperature gradient and super-cooling degree under the repeated rapid solidification and annealing treatment cycle inherent to WAAM-CMT. Both 25 °C (RT) and 350 °C (HT) tensile properties are well above the ASTM A370 criteria due to the dispersion-strengthening of dendritic ferrite within hierarchical-structure molten pools, coupled with the pinning effects of high-density dislocation tangles and cellular sub-grain boundaries as well as the annihilation of harmful intermetallic precipitates like σ phase and carbides that could become crack initiation. Further studies should pay attention to inhibiting the surface oxidation of each depositing layer and reducing the amounts of internal micron pores and δ-ferrite so as to suppress Cr-Mo-Ni atomic segregation and improve inter-granular corrosion resistance preferably without post-weld heat treatment.

Structure of Collagen.

Collagen is the most abundant fibrous protein in nature and widely exists in tissues such as connective tissue, tendon, skin, bone, and cartilage. On the one hand, collagen provides mechanical support in tissues, and on the other hand, plays an important role in controlling cell adhesion, cell migration, and tissue repair. A systematic understanding of the structure of collagen can promote the understanding of the biological functions of collagen scaffolds, and also provide theoretical guidance for applications of these natural fibrous protein materials. Therefore, this chapter centers on introducing the structure of collagen. As collagen has a typical hierarchical structure, the introduction to its structure will also be divided into different structural levels, from primary structure to quaternary structure. Due to the diversity of collagen types, this chapter will mainly focus on type I collagen.

Integrating Mobile Robots into Automated Laboratory Processes: A Suitable Workflow Management System.

The general trend of automation is currently increasing in life science laboratories. The samples to be examined show a high diversity in their structures and composition as well as the determination methods. Complex automation lines such as those used in classic industrial automation are not a suitable solution with respect to the required flexibility of the systems due to changing application requirements. Rather, full automation requires the connection of several different subsystems, including manual process steps by the laboratory staff. This requires suitable workflow management systems that enable the planning and execution of complex process steps. The integration of mobile robots for transportation tasks is currently an important development trend for realizing full automation in life science laboratories. The article "Workflow Management System for the Integration of Mobile Robots in Future Labs of Life Sciences" presents the development and application of a hierarchical workflow management system (HWMS) as a top-level process management and control system. This concept combines the typical hierarchical automation structure with novel approaches for the integration of transportation tasks with variable degrees of automation. The aim is to create a general-purpose workflow management system that can be used in different areas of the life sciences, regardless of the specific device components and applications used.

Study on dynamics and freezing behaviors of water droplet on superhydrophobic aluminum surface

In this work, a kind of superhydrophobic aluminum surface (treated-Al-SA) is fabricated by chemical etching using hydrochloric acid and hydrogen peroxide, and then treated by stearic acid. The surface of treated-Al-SA has typical hierarchical structure, which hold its durable superhydrophobicity under water droplet impact test, bending test, temperature test, humidity test and corrosive liquids test. Moreover, treated-Al-SA show excellent self-cleaning property at the different tilt angle under room temperature. Results on the dynamic behavior of water droplet is indicated the good anti-adhesion and superhydrophobicity of the treated-Al-SA. The whole freezing process of the water droplets on the surface of untreated-Al and treated-Al-SA is observed. The freezing time of treated-Al-SA is 59 s, which is longer than that of untreated-Al. It is estimated that the different anti-freezing behavior is caused by the thermal conductivity between the water droplet and plate, which is provided an insight into freezing characteristics of water droplet. This study is offered the novel opinion of the superhydrophobic aluminum surface produced by chemical etching, which may help the application of structured aluminum surface.

Rational construction of MOF derived hollow leaf-like Ni/Co(VO3)x(OH)2-x for enhanced supercapacitor performance

It is well known that the elements doping and morphology adjusting strategy are an effective ways to enhance the performance of supercapacitor electrode materials. In this work, using a Co-MOF as a precursor, a series of hollow-porous leaf-like V-doped nickel-cobalt layered double hydroxides (Ni-Co/V) nanosheets are successfully fabricated through a step-to-step etching process. The optimized Ni-Co/V-12-2 hollow leaf-like structure presents a typical hierarchical structure constructed by ultra-thin nanosheets and a hybrid pore of micro-/meso-porous with a BET surface area of 126.3 m2 g−1, which will provide the more active site and rich diffusion channels for enhanced energy storage performance. Therefore, the Ni-Co/V-12-2 electrode exhibits a high capacity of 161.4 mAh g−1 at 1 A g−1 and excellent cycle stability of maintaining 93.14% after 5600 cycles. Moreover, a hybrid supercapacitor with the Ni-Co/V-12-2 as the positive electrode and reduced graphene oxide (PPD/rGO) as the negative electrode, performs a high energy density of 55.22 Wh kg−1 at the power density of 0.375 kW kg−1.

Sustainable online communities exhibit distinct hierarchical structures across scales of size.

As humans, we are uniquely competent at incorporating ourselves into groups that scale up from a few members to millions of individuals to engage in joint activities in social circles of varying sizes. Yet, the question of how a group's survival depends on its social structure is not well understood. In an analysis of more than 10 122 real-life online communities (with a total of 134 147 members) hosted by a leading platform over periods of more than a decade, we observe a prominent structural difference between stable and unstable communities, enabling the prediction of sustainability up to a decade ahead. We find that communities that fail to maintain a typical hierarchical social structure that preserves cohesiveness across size scales do not survive, while communities that exhibit such balance prevail. This difference is observable in as early as the first 30 days of a community's lifetime, enabling prediction of community sustainability up to 10 years in the future. We theorize that communities comprising distinct social structures that balance global and local factors across scales of sizes are more likely to maintain sustainability.

Multi-Scale Identification of Urban Landscape Structure Based on Two-Dimensional Wavelet Analysis: The Case of Metropolitan Beijing, China

Scale dependence is one of the major characteristics of landscape. Urban landscape is highly affected by human activities with a multi-scale structure, which makes the multi-scale identification of urban structure an obligation for urban spatial studies. Although there have been many previous studies on urban landscape structure, most of them have been conducted on a single scale, and the multi-scale effects of landscape patterns were rarely involved. Two-dimensional wavelet transforms can link spatial structures to scale and spatial locations, and maybe an effective method for the multi-scale analysis of landscape. In this paper, we applied two-dimensional discrete wavelet transform and wavelet variance to analyze the multi-scale spatial structure characteristics and the nested hierarchical structure of the metropolitan Beijing area. The results indicated that the spatial distribution and configuration of the patches were highly scattered at small scales, and the urban landscape exhibited a relatively complicated structure. At medium scales, a combination of the polycentric and sectorial structure was identified due to the prominence of dominant patches within each administrative district. At larger scales, the urban landscape pattern exhibits typical concentric ring characteristics. Two characteristic scales were detected by the wavelet variance in the south-north direction of the main urban zones, scale 4 (112m) and 8 (1792m) in Dongcheng District, scale 3 (56m) and 6 (448m) in Xicheng District, which were corresponding to the extent of middle-small blocks and large blocks respectively. One characteristic scale was detected in each of the suburb areas (Chaoyang, Haidian, and Fengtai District). The spatial structure of the main urban zones is more complex than that of the suburb areas, and it presents a typical hierarchical structure in the south-north direction. In general, the spatial structure of Beijing metropolitan area appears polycentric and concentric ring structure at large scales, the main urban area has nested hierarchies at different characteristic scales, and the wavelet method can effectively identify multi-scale characteristics of urban spatial structure.

Facile synthesis of FeCo layered double oxide/raspberry-like carbon microspheres with hierarchical structure for electromagnetic wave absorption

Transition metal compositions (Fe, Co and Ni) have always been promising candidates for electromagnetic wave (EMW) absorbers. In this study, the FeCo layered double hydroxide (LDH) supported on raspberry-like carbon spheres (RCs) was synthesized by a simple hydrothermal method and the spontaneous electrostatic self-assembly process. The surface FeCo-LDH is then transformed into FeCo layered double oxide (LDO) with different compositions after calcination treatment (650 °C and 700 °C), forming a typical hierarchical structure. The sample calcined at 700 °C exhibited an ultra-wide effective absorption bandwidth (fe) (RL < −10 dB) of 7.4 GHz (from 10.6 to 18.0 GHz) at the matched thickness of 2.2 mm. The remarkable EM wave absorption properties are attributed to the strong interface polarization due to the various phase boundaries in LDO shell as well as sufficient heterointerfaces between LDO shell and RCs. It should be emphasized that LDH is rarely used for EMW absorption, and the use of LDH positively charged characteristics to fabricate hierarchical materials is a meaningful attempt and confirms the potential of LDH in EMW absorbing materials.

PAM: an efficient power-aware multilevel cache policy to reduce energy consumption of storage systems

Energy consumption is one of the most significant aspects of large-scale storage systems where multilevel caches are widely used. In a typical hierarchical storage structure, upper-level storage serves as a cache for the lower level, forming a distributed multilevel cache system. In the past two decades, several classic LRU-based multilevel cache policies have been proposed to improve the overall I/O performance of storage systems. However, few power-aware multilevel cache policies focus on the storage devices in the bottom level, which consume more than 27% of the energy of the whole system [1]. To address this problem, we propose a novel power-aware multilevel cache (PAM) policy that can reduce the energy consumption of high-performance and I/O bandwidth storage devices. In our PAM policy, an appropriate number of cold dirty blocks in the upper level cache are identified and selected to flush directly to the storage devices, providing high probability extension of the lifetime of disks in standby mode. To demonstrate the effectiveness of our proposed policy, we conduct several simulations with real-world traces. Compared to existing popular cache schemes such as PA-LRU, PB-LRU, and Demote, PAM reduces power consumption by up to 15% under different I/O workloads, and improves energy efficiency by up to 50.5%.