17,747 research outputs found
Does participatory water management contribute to smallholder incomes? Evidence from Minle County, Gansu Province, P.R. China
Since the early 1990s, the Chinese water sector has undergone an important institutional reform that has shifted major responsibilities in irrigation management from the government toward water users, organized in so-called Water User Associations (WUAs). Such participatory water management is not only assumed to increase water use efficiency, but also to stimulate the incomes of member households. This study aims to provide empirical evidence of the impact of participatory water management on WUA performance and farmer incomes, using data collected for the year 2007 among 317 households and 35 WUAs in Minle County, Gansu Province. We find that having democratically elected leaders has a positive effect on WUA performance, by increasing investment levels and improving canal quality. Participation in decision making, however, has a significant negative impact on canal quality and does not affect other WUA performance indicators. Two aspects of WUA performance, investment levels and financial health, are found to have a positive impact on the farm income of member households, while water use per mu has a significant negative impact on farm incomes. We find evidence that households belonging to better performing WUAs increase their farm incomes at the expense of non-farm income. The resulting net impact of participatory water management on total household income is not significant for the households in our sample
Earthquake source parameters of the 2009 Mw 7.8 Fiordland (New Zealand) earthquake from L-band InSAR observations
The 2009 MW7.8 Fiordland (New Zealand) earthquake is the largest to have occurred in New Zealand since the 1931 Mw 7.8 Hawke’s Bay earthquake, 1 000 km to the northwest. In this paper two tracks of ALOS PALSAR interferograms (one ascending and one descending) are used to determine fault geometry and slip distribution of this large earthquake. Modeling the event as dislocation in an elastic half-space suggests that the earthquake resulted from slip on a SSW-NNE orientated thrust fault that is associated with the subduction between the Pacific and Australian Plates, with oblique displacement of up to 6.3 m. This finding is consistent with the preliminary studies undertaken by the USGS using seismic data
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Two novel nonlinear companding schemes with iterative receiver to reduce PAPR in multi-carrier modulation systems
Companding transform is an efficient and simple method to reduce the Peak-to-Average Power Ratio (PAPR) for Multi-Carrier Modulation (MCM) systems. But if the MCM signal is only simply operated by inverse companding transform at the receiver, the resultant spectrum may exhibit severe in-band and out-of-band radiation of the distortion components, and considerable peak regrowth by excessive channel noises etc. In order to prevent these problems from occurring, in this paper, two novel nonlinear companding schemes with a iterative receiver are proposed to reduce the PAPR. By transforming the amplitude or power of the original MCM signals into uniform distributed signals, the novel schemes can effectively reduce PAPR for different modulation formats and sub-carrier sizes. Despite moderate complexity increasing at the receiver, but it is especially suitable to be combined with iterative channel estimation. Computer simulation results show that the proposed schemes can offer good system performances without any bandwidth expansion
An optimized analytical method for the simultaneous detection of iodoform, iodoacetic acid, and other trihalomethanes and haloacetic acids in drinking water
An optimized method is presented using liquid-liquid extraction and derivatization for the extraction of iodoacetic acid (IAA) and other haloacetic acids (HAA9) and direct extraction of iodoform (IF) and other trihalomethanes (THM4) from drinking water, followed by detection by gas chromatography with electron capture detection (GC-ECD). A Doehlert experimental design was performed to determine the optimum conditions for the five most significant factors in the derivatization step: namely, the volume and concentration of acidic methanol (optimized values = 15%, 1 mL), the volume and concentration of Na2SO4 solution (129 g/L, 8.5 mL), and the volume of saturated NaHCO3 solution (1 mL). Also, derivatization time and temperature were optimized by a two-variable Doehlert design, resulting in the following optimized parameters: an extraction time of 11 minutes for IF and THM4 and 14 minutes for IAA and HAA9; mass of anhydrous Na2SO4 of 4 g for IF and THM4 and 16 g for IAA and HAA9; derivatization time of 160 min and temperature at 40°C. Under optimal conditions, the optimized procedure achieves excellent linearity (R2 ranges 0.9990–0.9998), low detection limits (0.0008–0.2 µg/L), low quantification limits (0.008–0.4 µg/L), and good recovery (86.6%–106.3%). Intra- and inter-day precision were less than 8.9% and 8.8%, respectively. The method was validated by applying it to the analysis of raw, flocculated, settled, and finished waters collected from a water treatment plant in China
Some analysis on mobile-agent based network routing
©2004 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.Deployment of mobile agents in network-based applications has attracted lots of attentions in recent years. How to control the activities of agents is crucial for effective application of mobile agents. This paper focuses on the application of mobile agents in network routing. Two important activity properties of mobile agents are identified: the probability of success (the probability of finding the destination) and the distribution of mobile agents running in the network. To our knowledge, little work has been done on these two aspects. Our results show that the number of mobile agents can be controlled by adjusting the number of agents generated per request and the number of jumps each mobile agent can move. Thus, we can improve network performance by tuning relevant parameters.Wenyu Qu, Hong She
BERT with History Answer Embedding for Conversational Question Answering
Conversational search is an emerging topic in the information retrieval
community. One of the major challenges to multi-turn conversational search is
to model the conversation history to answer the current question. Existing
methods either prepend history turns to the current question or use complicated
attention mechanisms to model the history. We propose a conceptually simple yet
highly effective approach referred to as history answer embedding. It enables
seamless integration of conversation history into a conversational question
answering (ConvQA) model built on BERT (Bidirectional Encoder Representations
from Transformers). We first explain our view that ConvQA is a simplified but
concrete setting of conversational search, and then we provide a general
framework to solve ConvQA. We further demonstrate the effectiveness of our
approach under this framework. Finally, we analyze the impact of different
numbers of history turns under different settings to provide new insights into
conversation history modeling in ConvQA.Comment: Accepted to SIGIR 2019 as a short pape
Assessment of wind-induced fatigue crack initiation life at guyed mast earplate joints considering welding residual stresses
A new method for assessing the degree of the cumulative fatigue crack initiation damage of the welds of earplate joints of a guyed mast,which connect the mast with the cable,is proposed.Based on the multi-scale wind-induced stress analysis of the earplate joint,and considering the welding residual stresses at the earplate joints,the critical plane approach is used for the calculation of the cumulative strain fatigue damage due to combined actions of the welding residual stresses and wind load.The multi-axis fatigue accumulative damages of the welds of earplate joints in different wind orientations and at different wind average velocities are then evaluated on basis of Mason-coffin formula and Miner fatigue accumulative damage rule.The crack germination life is also calculated from the total damage
Deducing topology of protein-protein interaction networks from experimentally measured sub-networks.
BackgroundProtein-protein interaction networks are commonly sampled using yeast two hybrid approaches. However, whether topological information reaped from these experimentally-measured sub-networks can be extrapolated to complete protein-protein interaction networks is unclear.ResultsBy analyzing various experimental protein-protein interaction datasets, we found that they are not random samples of the parent networks. Based on the experimental bait-prey behaviors, our computer simulations show that these non-random sampling features may affect the topological information. We tested the hypothesis that a core sub-network exists within the experimentally sampled network that better maintains the topological characteristics of the parent protein-protein interaction network. We developed a method to filter the experimentally sampled network to result in a core sub-network that more accurately reflects the topology of the parent network. These findings have fundamental implications for large-scale protein interaction studies and for our understanding of the behavior of cellular networks.ConclusionThe topological information from experimental measured networks network as is may not be the correct source for topological information about the parent protein-protein interaction network. We define a core sub-network that more accurately reflects the topology of the parent network
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