1,721,129 research outputs found
Roadless areas as an effective strategy for protected area expansion: Evidence from China
No full textThe post-2020 global biodiversity framework aims to expand the global coverage of protected areas (and other effective area-based conservation measures) to 30% by 2030. Roadless areas are ecologically important and can play a role in achieving this target but lack explicit emphasis in conservation frameworks. Here, we identify roadless areas qualified for protected area expansion in China. It is estimated that 53% of China's territory remained roadless (78% unprotected) in 2018. Roadless areas encompass higher conservation values than existing protected areas. We propose 4 strategies based on different value propositions for selecting roadless areas to expand protected areas to 30% national coverage. These strategies will make protected areas perform better in reducing human disturbance, improving spatial imbalances, and increasing species representation. However, protecting roadless areas will generate social trade-offs between protection demand objectives and economic growth generated from roads, especially in the surroundings of major urban agglomerations
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
An Improved Circulating Current Injection Method for Modular Multilevel Converters in Variable-Speed Drives
No full textModular multilevel converters (MMC) represent an interesting and emerging topology in medium-voltage motor drive applications. The main challenge of using such a topology in variable-speed drives is the large voltage ripple of submodule capacitors at low speed with constant torque. In this paper, an improved circulating current injection method is proposed, which does not completely eliminate the capacitor voltage ripple, but maintains it bounded within reasonable values. As a result, magnitude of injected circulating current is reduced, leading to converter efficiency improvement and reduction of semiconductor current ratings. Dimensioning of submodule capacitance is also discussed, which is an important consideration when designing the MMCs in variable-speed drives. The proposed method has been successfully validated by simulation and experimental results
Use soft-decision error-correction codes in Phase-Change Memory
No full textResearches indicate that the resistance of phase-change material will become larger over the time. Use time-aware based soft-decision error correction code, which needs LLR to decode, can correct the errors in multilevel PCM effectively. Accurate LLR needs to read the resistance accurately, which will lead to a longer transmission latency. In this paper, we proposed a non-uniform correction strategy, which can reduce the read levels maintaining bit-error-rate performance. We use LDPC in correction of 4-level per cell PCM, and get the result via computer simulation. ? 2015 IEEE.E
Asymmetric Mode Control of MMC to Suppress Capacitor Voltage Ripples in Low-Frequency, Low-Voltage Conditions
No full textThis paper proposes an asymmetric mode control for a modular multilevel converter (MMC) operating at low-frequency and low-output-voltage conditions. Differently from conventional symmetric operations, affected by large capacitor voltage ripples caused by the large dc-link voltage, with the proposed asymmetric mode MMC operations, one arm does not produce output current and applies the major dc-link voltage, whereas the other arm sustains almost all output current with low dc-link voltage. Variations of the power level in arms remain bounded and the MMC does not need any other power exchange technique such as high-frequency or harmonic current injection in a low-frequency/low-voltage condition to suppress the capacitor voltage ripple. The asymmetric control realization, and arm energy regulation and its optimization are presented in detail. Experimental and simulation results show that the proposed method is suitable for motor drives operating under 20 Hz
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Model the Hidden Cost of China’s 2060 Carbon Neutrality: Potential Biodiversity Impacts of Wind and Solar Energy Expansion
No full textLarge-scale renewable energy deployments, as urgent solutions to mitigate climate change and its consequences, are reshaping the landscape in the human-environment nexus. Albeit promoted as pathways to bend the curve of biodiversity loss through their emission reduction and habitat restoration potential, renewables require significant land assets per unit energy and could impose high cost to ecosystems, triggering potential conflicts between global climate mitigation and biodiversity conservation. As China expanding its landscape of large-scale wind and solar energy facilities to fulfill its ambitious “2060 Carbon Neutrality” goals, an assessment of the potential areas of such concerns at a high resolution can provide insights for stakeholders to effectively manage biodiversity impacts of renewable power transitions. This project used suitability analysis to identify and predict the potential land use conflict between wind and solar energy expansion and biodiversity conservation in China under the 2060 announced pledge scenario in contrast to the biz-as-usual model of renewables expansion rate. We also quantify the biodiversity impacts of such expansion scenarios by estimating the mean richness and rarity scores, along with ecosystem service values and conflicting zones with Key Biodiversity Areas. Although our results indicated the renewables expansion under China’s ambitious goals tend not to encroach a high ratio of prioritized areas for biodiversity, the potential impacts in regions without the strictest protection are still worth investigation, as illustrated in our case studies for the Qilianshan-Qinghaihu Region and Hainan Province. The study provides insights for decision-makers to develop renewable energy facilities while protecting biodiversity and ecosystem services
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