A Personalized Facet-Weight Based Ranking Method for Service Component Retrieval

With the recent advanced computing, networking technologies and embedded systems, the computing paradigm has switched from mainframe and desktop computing to ubiquitous computing, one of whose visions is to provide intelligent, personalized and comprehensive services to users. As a new paradigm, Active Services is proposed to generate such services by retrieving, adapting, and composing of existing service components to satisfy user requirements. As the popularity of this paradigm and hence the number of service components increases, how to efficiently retrieve components to maximally meet user requirements has become a fundamental and significant problem. However, traditional facet-based retrieval methods only simply list out all the results without any kind of ranking and do not lay any emphasis on the differences of importance on each facet value in user requirements, which makes it hard for user to quickly select suitable components from the resulting list. To solve the problems, this paper proposes a novel personalized facet-weight based ranking method for service component retrieval, which assigns a weight for each facet to distinguish the importance of the facets, and constructs a personalized model to automatically calculate facet-weights for users according to their histo -rical retrieval records of the facet values and the weight setting. We optimize the parameters of the personalized model, evaluate the performance of the proposed retrieval method, and compare with the traditional facet-based matching methods. The experimental results show promising results in terms of retrieval accuracy and execution time

Enhanced sulfide removal and bioelectricity generation in microbial fuel cells with anodes modified by vertically oriented nanosheets

<p>Anode materials and structures are of critical importance for microbial fuel cells (MFCs) recovering energy from toxic substrates. Carbon-fiber-felt anodes modified by layers of vertically oriented TiO₂ and Fe₂O₃ nanosheets were applied in the present study. Enhanced sulfide removal efficiencies (both over 90%) were obtained after a 48-h operation, with maximum power densities improved by 1.53 and 1.36 folds compared with MFCs with raw carbon-fiber-felt anode. The modified anodes provided more active sites for microbial adhesion with increasing biomass densities. High-throughput 16S rRNA gene sequencing analysis also indicated the increase in microbial diversities. Bacteroidetes responsible for bioelectricity generation with <i>Thiobacillus</i> and <i>Spirochaeta</i> dominating sulfide removal were found in the MFCs with the modified anodes, with less anaerobic fermentative bacteria as Firmicutes appeared. This indicates that the proposed materials are competitive for applications of MFCs generating bioelectricity from toxic sulfide.</p

Incision History of the Middle Yellow River

The Yellow River follows a circuitous path around its middle reach and almost completely encircles the Ordos crustal block. The history of the Yellow River, both in terms of its integration and its incision history is complex and controversial, especially in the middle reach. How the Yellow River develops its drainage pattern is debated. Correspondingly, when the current drainage pattern established is also highly controversial, ranging from the late Miocene to the late Pleistocene. Deformed river terraces serve as a landscape feature to investigate tectonic activity, however, at timescales over about 105 yr, most markers, including river terraces, are destroyed by river erosion. The increasing fragmentation of preserved terraces through time can limit investigations on landscape deformation history. Base level fall on a tributary is genetically related to its trunk channel incision through the incision rate of the confluence point. We leverage this relationship to reconstruct a scaled incision history at each confluence point from an inversion analysis of tributary networks governed by the stream power law, and create a virtual metric, named as a “pseudo-terrace”, to recover the longer-term (~106 yr) incision and uplift history. The results of the profile inversion are given as a rock uplift rate history of each tributary with respect to its confluence with the Yellow River, which is equivalent to the incision history for both tributary and trunk river at the confluence. Converting the incision rate history into an isochronal surface elevation gives the pseudo-terrace plot for the middle Yellow River. Pseudo-terraces can be interpreted in terms of either variations in rock uplift rate or incision of a transient river profile, just as preserved fluvial terraces are. We investigate incision pattern of the trunk channel along the Jinshan Gorge in this way. The pattern shows higher river incision rates in the southern Ordos Block. Besides the large-scale pattern, smaller offsets and tilts of pseudo-terraces are also illustrated, indicating surface or near-surface faulting or folding was active in the past 2 Ma. To provide a more comprehensive view of spatiotemporal variations of incision along the Jinshan Gorge, we study the late Quaternary fluvial terraces in six tributaries along the Gorge. We also incorporate the incision history recorded by river channel profiles. Combined with quantitative analysis of the tributary channel profiles, we reconstruct incision rate variations through time for each tributary. Our result shows that all tributaries experienced a long-term stable fluvial incision since the late Miocene, and the stable incision rates decrease to the north. Since the Pleistocene, there has been increasing fluvial incision that sustained for several hundred thousand years for tributaries in the southern Gorge, but incision in the north kept stable with limited variation. The slow incision rates, stable since late Miocene, contradicts the hypothesis of recent integration in the middle Yellow River, whereas the spatially heterogeneous incision variation during the Pleistocene seems related to recently enhanced tectonic activities. Upstream of tributaries on the Ordos Block have been not impacted by the recently enhanced tectonic uplift. The Block is characterized with limited changes in tectonic activity and lithology, and situated in a semi-arid to arid transition zone, which provide a natural experiment to investigate how precipitation affects landscape evolution by different surface processes. Here we present a spatially dramatic transition in relief in the middle Ordos Block, that coincides with a precipitation gradient across the Block. Topographic change occurs over a short range in precipitation rates, and outside this range landscape morphology appears to be insensitive to precipitation rates. We interpret this transition as a boundary between aeolian-dominated and fluvial dominated regimes

Climate oscillations and erosional processes in the Ordos tectonic block and implications for sediment supply to the Yellow River

Climate variations in both space and time can impact mountain topography and drainage-basin morphology through a variety of surface processes. This is illustrated dramatically in the Ordos Block of northern China, which encompasses the main body of the Loess Plateau in the southeast and the Mu Us Desert in the northwest. The plateau is known for severe soil erosion by fluvial processes; whereas the desert is dominated by aeolian processes. Here we characterize the spatial transition in landscape relief and drainage network integration of the middle Ordos Block, corresponding to a precipitation gradient across the region, that is otherwise homogeneous in terms of its tectonics and bedrock. Differences in landscape relief and drainage network integration occur over a short range in precipitation rate, and outside this transition zone, landscape morphologic metrics appear to be relatively insensitive to precipitation. Where precipitation rates are greater than ∼420 mm/yr, landscapes are characterized by integrated drainage networks with relief over 100 m within a 1 km radius. With precipitation rates lower than ∼380 mm/yr, the landscapes tend to have lower relief, discontinuous channels and hundreds of playa lakes indicating inefficient runoff. Combined with stratigraphic records, we posit that continuous drainage networks in the semi-arid to arid transition zone expand in wetter periods, and shrink and fragment when precipitation falls below a threshold. Today the Ordos Block is experiencing the transition from a drier (glacial) stage to a wetter (interglacial) stage, with higher precipitation rates over the past ∼12 thousand years. It follows that fluvial processes likely have increased in efficiency and are currently advancing into regions to the northwest formerly dominated by aeolian processes. Our findings suggest that a component of the severe sediment erosion of the Loess Plateau is a transient feature locally associated with glacial-interglacial climate change and the transition from aeolian- to fluvial-dominated surface processes.ISSN:0012-821XISSN:1385-013

Spatial and Temporal Variations of Incision Rate of the Middle Yellow River and Its Tributaries

We present a model to reconstruct spatiotemporal variation of uplift along the Jinshan Gorge of the Yellow River of Northern China based on quantitative analysis of the river channel profiles. We focus on the tributaries along the gorge that drain from the Loess Plateau on the Ordos crustal block. Base level fall on a tributary is genetically related to its trunk channel incision through the incision rate of the confluence point. We leverage this relationship to reconstruct a scaled incision history at each confluence point from an inversion analysis of tributary networks governed by the stream power law. In this way, we create an artificial geomorphic marker, that we refer to as a “pseudo-terrace.” These metrics provide information on the incision history of the Yellow River. Our result shows a recent acceleration of river incision along the southern Jinshan Gorge, including spatial variations indicative of tectonic activity. The northern gorge exhibits more uniform and steady incision rates. This pattern can be attributed to on-going lithospheric mantle upwelling beneath the southern Ordos Block.ISSN:0148-0227ISSN:2169-9003ISSN:2169-901

A Joint Web Resource Recommendation Method based on Category Tree and Associate Graph

Personalized recommendation is valuable in various web applications, such as e-commerce, music sharing, and news releasing, etc. Most existing recommendation methods require users to register and provide their private information before gaining access to any services, whereas a majority of users are reluctant to do so, which greatly limits the range of application of such recommendation methods. In the non-register environments, the only available information is the content or attributes of resources and the click-through chains of user sessions, so that many recommendation methods fail to work effectively due to the rating sparsity [Adomavicius and Tuzhilin, 2005] and illegibility of user identity, collaborative filtering [Goldberg et al. 1992] is an example of this case. In this paper we propose a joint recommendation method combining together two approaches, namely the domain category tree and the associate graph, to make full use of all available information. Further, an associate graph propagation method is designed to improve the traditional associate filtering method by integrating additional graphical considerations into them. Experiment results show that our method outperforms either the single category tree approach or the single associate graph approach, and it can provide acceptable recommendation services even in the non-register environment

A Joint Web Resource Recommendation Method based on Category Tree and Associate Graph

Personalized recommendation is valuable in various web applications, such as e-commerce, music sharing, and news releasing, etc. Most existing recommendation methods require users to register and provide their private information before gaining access to any services, whereas a majority of users are reluctant to do so, which greatly limits the range of application of such recommendation methods. In the non-register environments, the only available information is the content or attributes of resources and the click-through chains of user sessions, so that many recommendation methods fail to work effectively due to the rating sparsity [Adomavicius and Tuzhilin, 2005] and illegibility of user identity, collaborative filtering [Goldberg et al. 1992] is an example of this case. In this paper we propose a joint recommendation method combining together two approaches, namely the domain category tree and the associate graph, to make full use of all available information. Further, an associate graph propagation method is designed to improve the traditional associate filtering method by integrating additional graphical considerations into them. Experiment results show that our method outperforms either the single category tree approach or the single associate graph approach, and it can provide acceptable recommendation services even in the non-register environment

Characterization of EIAV <i>env</i> Quasispecies during Long-Term Passage In Vitro: Gradual Loss of Pathogenicity

As the only widely used live lentiviral vaccine, the equine infectious anima virus (EIAV) attenuated vaccine was developed by in vitro passaging of a virulent strain for 121 generations. In our previous study, we observed that the attenuated vaccine was gradually selected under increased environmental pressure at the population level (termed a quasispecies). To further elucidate the potential correlation between viral quasispecies evolution and pathogenesis, a systematic study was performed by sequencing env using several methods. Some key mutations were identified within Env, and we observed that increased percentages of these mutations were accompanied by an increased passage number and attenuated virulence. Phylogenetic analysis revealed that env mutations related to the loss of virulence might have occurred evolutionarily. Among these mutations, deletion of amino acid 236 in the V4 region of Env resulted in the loss of one N-glycosylation site that was crucial for virulence. Notably, the 236-deleted sequence represented a &#8220;vaccine-specific&#8222; mutation that was also found in wild EIAVLN40 strains based on single genome amplification (SGA) analysis. Therefore, our results suggest that the EIAV attenuated vaccine may originate from a branch of quasispecies of EIAVLN40. Generally, the presented results may increase our understanding of the attenuation mechanism of the EIAV vaccine and provide more information about the evolution of other lentiviruses