This paper proposes a new measure for recommendation through integrating Triangle and Jaccard similarities. The Triangle similarity considers both the length and the angle of rating vectors between ...them, while the Jaccard similarity considers non co-rating users. We compare the new similarity measure with eight state-of-the-art ones on four popular datasets under the leave-one-out scenario. Results show that the new measure outperforms all the counterparts in terms of the mean absolute error and the root mean square error.
Recommender systems employ recommendation algorithms to predict users’ preferences to items. These preferences are often represented as numerical ratings. However, existing recommender systems seldom ...suggest the appropriate behavior together with the numerical prediction, nor do they consider various types of costs in the recommendation process. In this paper, we propose a regression-based three-way recommender system that aims to minimize the average cost by adjusting the thresholds for different behaviors. This is undertaken using a step-by-step approach, starting with simple problems and progressing to more complex ones. First, we employ memory-based regression approaches for binary recommendation to minimize the loss. Next, we consider misclassification costs and adjust the approaches to minimize the average cost. Finally, we introduce coupon distribution action with promotion cost, and propose two optimal threshold-determination approaches based on the three-way decision model. From the viewpoint of granular computing, a three-way decision is a good tradeoff between the numerical rating and binary recommendation. Experimental results on the well-known MovieLens data set show that threshold settings are critical to the performance of the recommender, and that our approaches can compute unique optimal thresholds.
Realizing of full-color quantum-dot LED display remains a challenge because of the poor stability of the blue quantum-dot and the immature inkjet-printing color patterning technology. Here, we ...develop a multifunctional tandem LED by stacking a yellow quantum-dot LED with a blue organic LED using an indium-zinc oxide intermediate connecting electrode. Under parallel connection and alternate-current driving, the tandem LED is full-color-tunable, which can emit red, green and blue primary colors as well as arbitrary colors that cover a 63% National Television System Committee color triangle. Under series connection and direct current driving, the tandem LED can emit efficient white light with a high brightness of 107000 cd m
and a maximum external quantum efficiency up to 26.02%. The demonstrated hybrid tandem LED, with multi-functionality of full-color-tunability and white light-emission, could find potential applications in both full-color-display and solid-state-lighting.
Recently, many literature works have considered the security issues of wireless networked control system (WNCS). However, few works studied how the attacker should optimize its attack schedule in ...order to maximize the effect on the system performance due to the insufficiency of energy at the attacker side. This paper fills this gap from the aspect of control system performance. We consider the optimal jamming attack that maximizes the Linear Quadratic Gaussian (LQG) control cost function under energy constraint. After analyzing the properties of the cost function under an arbitrary attack schedule, we derive the optimal jamming attack schedule and the corresponding cost function. System stability under this optimal attack schedule is also considered. We further investigate the optimal attack schedule in a WNCS with multiple subsystems. Different examples are provided to demonstrate the effectiveness of the proposed optimal denial-of-service attack schedule.
The aim of this study based on the panel data of 30 Chinese provinces obtained from 2000 to 2016 was to calculate the green total factor efficiency (GTFE) of industrial water resources by applying ...the Super-Slack Based Measure (SBM) model of non-expected output, and to analyze the effect of core variables (technological innovation, environmental regulation, and the interaction of these two factors) and control variables (education level, industrial development and the degree of openness) on the GTFE of industrial water resources by making use of Stochastic Impacts by Regression on Population, Affluence, and Technology (STIRPAT) model and the dynamic panel system Generalized Method of Moments (GMM). The results show that technological innovation had no significant impact on the GTFE of industrial water resources in China and the eastern region. It had a restraining impact on the central region, while a positive effect on the western region. Environmental regulation was not conducive to the improvement of China's GTFE of industrial water resources, and the promotion of efficiency in the eastern, central, and western regions was not significant. The interaction between technological innovation and environmental regulation positively affected the GTFE of industrial water resources of China, whereas it had a negative impact on the central region and an insignificant impact on the eastern and central regions. This showed that there were regional, economic, and industrial structure differences in the effect of technological innovation and environmental regulation on the GTFE of industrial water resources. In addition, the first-phase lag of GTFE of industrial water resources in China and the central region, the degree of openness of China and eastern, central, and western regions, the education level of central residents, and the industrial development degree of western region effectively improved the GTFE of industrial water resources, whereas the education level of western residents had an inhibitory impact. Therefore, China needs to formulate a differentiated and diversified technological innovation system and environmental protection policy, improve the green research and development investment of industrial enterprises, and form a green development model; at the same time, China needs to guide rational consumption, develop high-tech industries, and adhere to opening up.
The exploring of catalysts with high‐efficiency and low‐cost for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is one of the key issues for many renewable energy systems ...including fuel cells, metal–air batteries, and water splitting. Despite several decades pursuing, bifunctional oxygen catalysts with high catalytic performance at low‐cost, especially the one that could be easily scaled up for mass production are still missing and highly desired. Herein, a hybrid catalyst with NiCo alloy nanoparticles decorated on N‐doped carbon nanofibers is synthesized by a facile electrospinning method and postcalcination treatment. The hybrid catalyst NiCo@N‐C 2 exhibits outstanding ORR and OER catalytic performances, which is even surprisingly superior to the commercial Pt/C and RuO2 catalysts, respectively. The synergetic effects between alloy nanoparticles and the N‐doped carbon fiber are considered as the main contributions for the excellent catalytic activities, which include decreasing the intrinsic and charge transfer resistances, increasing CC, graphitic‐N/pyridinic‐N contents in the hybrid catalyst. This work opens up a new way to fabricate high‐efficient, low‐cost oxygen catalysts with high production.
NiCo alloy nanoparticles decorated on N‐doped carbon nanofibers as a highly active and durable oxygen electrocatalyst at low‐cost are synthesized and reported. The hybrid catalyst with suitable amount of NiCo alloy nanoparticles loading (NiCo@N‐C 2) gives the most outstanding oxygen reduction reaction and oxygen evolution reaction electrocatalytic performances, which is even surprisingly superior to the commercial Pt/C and RuO2 catalysts, respectively.
Traditionally, the strata of the Luonie Valley, Dechang County, SW Sichuan, China, are considered to contain a suite of felsic volcanic rocks (the Huili Group) that erupted after c. 1050 Ma. However, ...we report here new age constraints, elemental and Lu–Hf isotope geochemistry for a different suite of older basaltic agglomerate lava, basaltic tuff lava and basalt from the same area, which we name the Luonie Formation. New dating results show that the basaltic volcanic suite of the upper part of the Luonie Formation formed at 1126.1 ± 9.9 Ma, significantly earlier than deposition of the Huili Group, but comparable in age to the 1142 ± 16 Ma Laowushan Formation in central Yunnan Province. Granite intrusion into the Luonie Formation dated 1050.7 ± 12.7 Ma provides crucial supporting evidence for this earlier depositional age. We also report a maximum sedimentary age of c. 1158 Ma for the underlying arkose, implying stratigraphic conformity with the basaltic volcanic rock suite. The ϵ
Hf(t) values of the basaltic volcanic rocks are mainly positive, indicating that the rocks are mainly derived from the depleted mantle and slightly stained by crustal materials. The characteristics of P*, Nb* and Zr* anomalies also support this view. The distribution patterns of trace and rare earth elements indicate that the basaltic volcanic rocks formed in an extensional setting. The Zr/4–Y–2Nb and Th–Nb/16–Zr/117 discrimination diagrams also provide evidence for this understanding. Lithofacies analysis shows that basaltic volcanic wrocks with the characteristics of both continental and marine facies should be formed in a littoral–neritic environment. We propose here that the evidence is consistent with a phase of continental extension that preceded the convergence of the SW Yangtze Block to form part of Rodinia.
•We propose a framework integrating three-way decision and random forests.•We introduce a new recommender action to consult the user for the choice.•We build a random forest to predict the ...probability that a user likes an item.•The three-way thresholds are optimal for both the training set and the testing set.
Recommender systems attempt to guide users in decisions related to choosing items based on inferences about their personal opinions. Most existing systems implicitly assume the underlying classification is binary, that is, a candidate item is either recommended or not. Here we propose an alternate framework that integrates three-way decision and random forests to build recommender systems. First, we consider both misclassification cost and teacher cost. The former is paid for wrong recommender behaviors, while the latter is paid to actively consult the user for his or her preferences. With these costs, a three-way decision model is built, and rational settings for positive and negative threshold values α* and β* are computed. We next construct a random forest to compute the probability P that a user will like an item. Finally, α*,0.35em0exβ*, and P are used to determine the recommender’s behavior. The performance of the recommender is evaluated on the basis of an average cost. Experimental results on the well-known MovieLens data set show that the (α*, β*)-pair determined by three-way decision is optimal not only on the training set, but also on the testing set.
The largest obstacle to the cost-competitive production of low-value and high-impact biofuels and biochemicals (called biocommodities) is high production costs catalyzed by microbes due to their ...inherent weaknesses, such as low product yield, slow reaction rate, high separation cost, intolerance to toxic products, and so on. This predominant whole-cell platform suffers from a mismatch between the primary goal of living microbes – cell proliferation and the desired biomanufacturing goal – desired products (not cell mass most times). In vitro synthetic biosystems consist of numerous enzymes as building bricks, enzyme complexes as building modules, and/or (biomimetic) coenzymes, which are assembled into synthetic enzymatic pathways for implementing complicated bioreactions. They emerge as an alternative solution for accomplishing a desired biotransformation without concerns of cell proliferation, complicated cellular regulation, and side-product formation. In addition to the most important advantage – high product yield, in vitro synthetic biosystems feature several other biomanufacturing advantages, such as fast reaction rate, easy product separation, open process control, broad reaction condition, tolerance to toxic substrates or products, and so on. In this perspective review, the general design rules of in vitro synthetic pathways are presented with eight supporting examples: hydrogen, n-butanol, isobutanol, electricity, starch, lactate,1,3-propanediol, and poly-3-hydroxylbutyrate. Also, a detailed economic analysis for enzymatic hydrogen production from carbohydrates is presented to illustrate some advantages of this system and the remaining challenges. Great market potentials will motivate worldwide efforts from multiple disciplines (i.e., chemistry, biology and engineering) to address the remaining obstacles pertaining to cost and stability of enzymes and coenzymes, standardized building parts and modules, biomimetic coenzymes, biosystem optimization, and scale-up, soon.
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