143 research outputs found
The investigation of motor current signals from a centrifugal pump for fault diagnosis
In this paper, motor current signals from electrical control systems, rather than installing additional measurement systems, are characterised for the fault diagnosis of centrifugal pumps. Modulation signal bispectrum (MSB) analysis is applied to reveal the weak nonlinear characteristics of current signals when the pump with different impeller faults operates under a wide range of flow conditions. Experimental results show that two static features including the amplitude at supply frequency and the frequency value of bar-passing frequency can be based on to diagnose impeller defects on exit vane tips and inlet vane tips. In addition, the dynamic parameter of sidebands at vane-passing frequency can also be a good indicator for differentiating between the faults
Do Imports Crowd Out Domestic Consumption? A Comparative Study of China,Japan and Korea
A decline in the relative price of imported goods compared to that of domestically produced goods, e.g., caused by domestic currency appreciation, may have different effects on domestic consumption. Such effects may not be accurately detected and measured in a classical permanent-income model without considering consumption habit formation as pointed out by Nishiyama (2005). To resolve this problem, this paper employs an extended permanent-income model which encompasses consumption habit formation. Both cointegration analysis and GMM are used to estimate the (modified) intertemporal elasticities of substitution (IES) between imports and domestic consumption and the parameters of habit formation as well as the (modified) intratemporal elasticities of substitution (AES). We find that import and domestic consumptions are complements in China, but substitutes in Japan and Korea. Different per capita incomes and consumer behaviors between China and the other two countries are two possible reasons for different relationships between import and domestic consumptions.This paper is published in China Economic Review 23 (2012), PP1036–1050
Physics-Informed Optical Kernel Regression Using Complex-valued Neural Fields
Lithography is fundamental to integrated circuit fabrication, necessitating
large computation overhead. The advancement of machine learning (ML)-based
lithography models alleviates the trade-offs between manufacturing process
expense and capability. However, all previous methods regard the lithography
system as an image-to-image black box mapping, utilizing network parameters to
learn by rote mappings from massive mask-to-aerial or mask-to-resist image
pairs, resulting in poor generalization capability. In this paper, we propose a
new ML-based paradigm disassembling the rigorous lithographic model into
non-parametric mask operations and learned optical kernels containing
determinant source, pupil, and lithography information. By optimizing
complex-valued neural fields to perform optical kernel regression from
coordinates, our method can accurately restore lithography system using a
small-scale training dataset with fewer parameters, demonstrating superior
generalization capability as well. Experiments show that our framework can use
31% of parameters while achieving 69 smaller mean squared error with
1.3 higher throughput than the state-of-the-art.Comment: Accepted by DAC2
A New MEMS Stochastic Model Order Reduction Method: Research and Application
Modeling and simulation of MEMS devices is a very complex tasks which involve the electrical, mechanical, fluidic, and thermal domains, and there are still some uncertainties that need to be accounted for during the robust design of MEMS actuators caused by uncertain material and/or geometric parameters. According to these problems, we put forward stochastic model order reduction method under random input conditions to facilitate fast time and frequency domain analyses; the method makes use of polynomial chaos expansions in terms of the random input variables for the matrices of a finite element model of the system and then uses its transformation matrix to reduce the model; the method is independent of the MOR algorithm, so it is seamlessly compatible with MOR method used in popular finite element solvers. The simulation results verify the method is effective in large scale MEMS design process
Genuine Wealth Per Capita as a Measure of Sustainability and the Negative Impact of Corruption on Sustainable Growth in Sub-Sahara Africa
In this paper we argue that the answer to the question of whether the impact of corruption on development is homogenous, is no. Our optimism rest on how development may be conceptualized. When equated to a narrow measure in economic-wise which fundamentally ignores critical issues, then there is a possibility the outlook could be positive. But when conceptualized using a broad-based approach such as sustainable development, then the outlook could be negative. We assess a panel of 22 economies in Sub-Sahara Africa with the most recent dataset (1996-2013) from the World Bank and other reputable agencies. Our finding is quite robust. It holds in POLS, Fixed effects and GMM within IV settings; and it also holds for different measures of institutions and different measures of development using growth per capita GDP and genuine wealth per capita respectively. Taking stock of major policy blue-prints of selected countries in the region on the fight against corruption, we are able to point out that institutions play important role in insulating citizens against the devastation caused by corruption. Overall, through this comparison, we are able to signal that both incidental and systematic corruption poses a long-term threat to sustainable development
CAMKs support development of acute myeloid leukemia.
BACKGROUND: We recently identified the human leukocyte immunoglobulin-like receptor B2 (LILRB2) and its mouse ortholog-paired Ig-like receptor (PirB) as receptors for several angiopoietin-like proteins (Angptls). We also demonstrated that PirB is important for the development of acute myeloid leukemia (AML), but exactly how an inhibitory receptor such as PirB can support cancer development is intriguing. RESULTS: Here, we showed that the activation of Ca (2+)/calmodulin-dependent protein kinases (CAMKs) is coupled with PirB signaling in AML cells. High expression of CAMKs is associated with a poor overall survival probability in patients with AML. Knockdown of CAMKI or CAMKIV decreased human acute leukemia development in vitro and in vivo. Mouse AML cells that are defective in PirB signaling had decreased activation of CAMKs, and the forced expression of CAMK partially rescued the PirB-defective phenotype in the MLL-AF9 AML mouse model. The inhibition of CAMK kinase activity or deletion of CAMKIV significantly slowed AML development and decreased the AML stem cell activity. We also found that CAMKIV acts through the phosphorylation of one of its well-known target (CREB) in AML cells. CONCLUSION: CAMKs are essential for the growth of human and mouse AML. The inhibition of CAMK signaling may become an effective strategy for treating leukemia
Causes of Corruption: Evidence from Sub-Sahara Africa
This study explores the causes of corruption for Sub-Sahara Africa in a panel of 22 countries from 1996 to 2013. The sources of corruption are grouped under three main thematic areas – historical roots, contemporary causes and institutional causes to make way for both subjective and objective measures. The subjective measures allow this paper to gauge the effectiveness of anticorruption policies. Focusing on three estimation strategies and using the perceived level of corruption as dependent variable, we find ethnic diversity, resource abundance and educational attainment to be markedly less associated with corruption; whereas wage levels of bureaucrats and anticorruption controls using government effectiveness and regulatory quality breeds substantial corruption. Press freedom was variedly associated with corruption. As a policy implication, the fight against corruption on the continent needs to be reinvented through qualitative institutional reforms. Existing educational systems should be used as medium to intensify awareness on the devastating effects of corruption on national development
Corruption, EU Aid Inflows and Economic Growth in Ghana: Cointegration and Causality Analysis
This paper uses the Johansen cointegration technique to examine the causal relationship between aid inflows and economic growth for Ghana during the period 1970-2013. To better reflect causality, corruption (governance) and trade are included as control variables. In order to test for causality in the face of cointegration among variables, a vector error correction model (VECM) is used in place of vector autoregressive (VAR) model. This is complemented with Toda and Yamamoto’s test to point to causal direction. Appropriate stability test to account for structural breaks in the series is undertaken. Our estimation results suggest that GDP growth has one cointegrating vector relationship with governance, EU aid inflows and trade in both short and long runs. There is a long run unidirectional causal relationship from EU Aid inflows to GDP growth, and a short run unidirectional causality from trade to GDP. Governance was ineffective to power growth. The error correction terms are the source of causation in the long. The results indeed confirm popular conjecture that corruption in Ghana stifles development. Therefore government’s decision to launch a national anti-corruption plan in 2011 though long overdue, but is justifiable. However, such an attempt will only be effective if and only if a conscious effort is made by all stakeholders to work in hand in deepening good governance (reducing corruption) as a trajectory for promoting economic growth and to serve as inducement for a continue aid inflows from multilateral donors to sustain efforts at achieving the millennium development goals in Ghana
Phylogenomics and morphological evolution of the mega-diverse genus Artemisia (Asteraceae: Anthemideae): implications for its circumscription and infrageneric taxonomy
Background and Aims
Artemisia is a mega-diverse genus consisting of ~400 species. Despite its medicinal importance and ecological significance, a well-resolved phylogeny for global Artemisia, a natural generic delimitation and infrageneric taxonomy remain missing, owing to the obstructions from limited taxon sampling and insufficient information on DNA markers. Its morphological characters, such as capitulum, life form and leaf, show marked variations and are widely used in its infrageneric taxonomy. However, their evolution within Artemisia is poorly understood. Here, we aimed to reconstruct a well-resolved phylogeny for global Artemisia via a phylogenomic approach, to infer the evolutionary patterns of its key morphological characters and to update its circumscription and infrageneric taxonomy.
Methods
We sampled 228 species (258 samples) of Artemisia and its allies from both fresh and herbarium collections, covering all the subgenera and its main geographical areas, and conducted a phylogenomic analysis based on nuclear single nucleotide polymorphisms (SNPs) obtained from genome skimming data. Based on the phylogenetic framework, we inferred the possible evolutionary patterns of six key morphological characters widely used in its previous taxonomy.
Key Results
The genus Kaschgaria was revealed to be nested in Artemisia with strong support. A well-resolved phylogeny of Artemisia consisting of eight highly supported clades was recovered, two of which were identified for the first time. Most of the previously recognized subgenera were not supported as monophyletic. Evolutionary inferences based on the six morphological characters showed that different states of these characters originated independently more than once.
Conclusions
The circumscription of Artemisia is enlarged to include the genus Kaschgaria. The morphological characters traditionally used for the infrageneric taxonomy of Artemisia do not match the new phylogenetic tree. They experienced a more complex evolutionary history than previously thought. We propose a revised infrageneric taxonomy of the newly circumscribed Artemisia, with eight recognized subgenera to accommodate the new results.This work was supported by the National Natural Science Foundation of China (grant nos. 31870179, 31570204, 31270237 and J1310002), the International Partnership Program (grant no. 151853KYSB20190027), Sino-Africa Joint Research Center (grant no. SAJC201614), Key technology projects of Jiangxi Province's major scientific and technological research and development project (grant no. 20223AAF01007), Survey of Wildlife Resources in Key Areas of Tibet (grant no. ZL202203601) and National Plant Specimen Resource Center (grant no. E0117G1001) of the Chinese Academy of Sciences, Key Project at Central Government Level: The Ability Establishment of Sustainable Use of Valuable Chinese Medicine Resources (grant no. 2060302) and Project of the Central Siberian Botanical Garden of the Siberian Branch of the Russian Academy of Sciences (grant no. AAAA-A21-121011290024-5).Abstract
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
Conclusions
SUPPLEMENTARY DATA
FUNDING
ACKNOWLEDGEMENTS
CONFLICT OF INTEREST
LITERATURE CITED
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