Latexify Math: Mathematical Formula Markup Revision to Assist Collaborative Editing in Math Q&A Sites

Collaborative editing questions and answers plays an important role in quality control of Mathematics StackExchange which is a math Q&A Site. Our study of post edits in Mathematics Stack Exchange shows that there is a large number of math-related edits about latexifying formulas, revising LaTeX and converting the blurred math formula screenshots to LaTeX sequence. Despite its importance, manually editing one math-related post especially those with complex mathematical formulas is time-consuming and error-prone even for experienced users. To assist post owners and editors to do this editing, we have developed an edit-assistance tool, MathLatexEdit for formula latexification, LaTeX revision and screenshot transcription. We formulate this formula editing task as a translation problem, in which an original post is translated to a revised post. MathLatexEdit implements a deep learning based approach including two encoder-decoder models for textual and visual LaTeX edit recommendation with math-specific inference. The two models are trained on large-scale historical original-edited post pairs and synthesized screenshot-formula pairs. Our evaluation of MathLatexEdit not only demonstrates the accuracy of our model, but also the usefulness of MathLatexEdit in editing real-world posts which are accepted in Mathematics Stack Exchange

Soil organic matter dynamics and nitrogen availability in response to site preparation and management during revegetation in tropical Central Queensland, Australia

Purpose: There is considerable interest in finding a cost-effective method of site preparation that effectively controls weeds during planting and further reduces the need for recurring herbicide applications. In this study, two weed control methods, herbicide and scalping, were examined. Both methods may have implications for soil organic matter (SOM) dynamics and nitrogen (N) which could consequently affect plant survival and vegetation establishment. This study aimed to investigate the dynamics of SOM, carbon (C) and N pools under site manipulation practices and the associated early plant survival and growth in tropical Australia. Materials and methods: A field trial was established in Central Queensland to examine the recovery of SOM, C and N pools following scalping and the alternative site preparation technique of sequential herbicide application. Both were contrasted with control plots which received neither treatment. Plant survival and growth were also monitored to improve our understanding of plant response to site preparation practices. Results and discussion: Scalped plots showed significantly lower values for labile C and N pools compared with the herbicide treatment and control. Generally, there was no significant difference between the herbicide and control for any of the parameters tested. Our observation indicated that herbicide application was significantly less effective than scalping to control weeds. A general decline in SOM parameters was observed in all the plots, including the control during the trial. Drought conditions were considered to be a major factor in the overall decline of SOM. Despite removal of the top soil, there was no significant difference in plant survival between herbicide and scalped areas (81% and 79% survival, respectively). Plant growth was not affected by the treatments in the first 6 months when weed competition in the herbicide areas and low nutrient availability in the scalped plots would have been significant factors in controlling growth rates. However, plants in the herbicide areas, irrespective of species, showed stronger growth than those in the scalped plots at week 61 when they had outgrown the weed competition. It is likely that differences in plant growth response to treatments will become negligible over time. Conclusions: Top soil removal was more effective than the use of herbicide in the long-term control of weeds. However, lower SOM and N availability in the scalped areas did not affect plant survival rates when compared with that of the herbicide areas. Whilst the preservation of soil organic matter is considered to be vital in short-term cropping systems, our results indicate that this is not the case for woody vegetation establishment and, in terms of cost and reduction of chemical use, removal of the organically rich top soil, with its accompanying seed burden may be both practical and desirable. © 2012 Springer-Verlag

Gate-emitter Pre-threshold Voltage as a Health Sensitive Parameter for IGBT Chip Failure Monitoring in High Voltage Multichip IGBT Power Modules

IEEE This paper proposes a novel health sensitive parameter, called the gate-emitter pre-threshold voltage VGE(pre-th), for detecting IGBT chip failures in multichip IGBT power modules. The proposed method has been applied in an IGBT gate driver and measures the VGE at a fixed time instant of the VGE transient before the threshold voltage occurs. To validate the proposed method, theoretical analysis and practical results for a 16-chip IGBT power module are presented in the paper. The results show a 500 mV average shift in the measured VGE(pre-th) for each IGBT chip failure

Effects of pre-planting site management on soil organic matter and microbial community functional diversity in subtropical Australia

Weed control is a key factor affecting early plant growth and establishment in revegetation projects in South-east Queensland of sub-tropical Australia. Costs associated with weed control are significant and methods which reduce establishment costs and effectively suppress weeds are of great interest. However, different methods may have implications for soil quality and fertility and require a detailed investigation. Understanding the response of soil organic matter (SOM) and microbial functional diversity to different weed control methods is crucial as they affect soil quality and nutrient availability. A field trial was established in South-east Queensland to identify the effects of three methods of weed control: (1) glyphosate, (2) a mixture of glyphosate and MCPA and (3) topsoil removal or scalping on SOM, microbial biomass, soil respiration, NH4+-N availability, potentially mineralisable N (PMN) and soil microbial community functional diversity (as assessed by carbon substrate utilisation using Biolog GN2 plates). The scalped area had lower SOM and microbial activity compared to the herbicide and control plots. There was no significant difference in water soluble organic carbon (WSOC), hot water extractable organic C (HWEOC), hot water extractable total N (HWETN) and microbial biomass C and N (MBC and MBN) between the herbicide and control plots, particularly at week 20. NH4+-N and PMN values were lower at week 20 than week 1 in the herbicide and scalping treatments. Week 20 was the end of the growing season and reduction in N availability may have been the result of decreasing temperature. Principal component analyses (PCA) from Biolog GN2 results indicated a separation in soil microbial community function in the scalped area compared to the other treatments which may have implications for soil properties in the long term.Scalping proved to be the most cost-effective method of site preparation, requiring fewer site visits for weed control compared to herbicide application. However, SOM was significantly affected by scalping due to topsoil removal and it may not be a sustainable practice in short rotation plantation establishment. Single herbicide application at field rates did not impact soil organisms but also failed to achieve proper weed control. © 2012 Elsevier B.V

PPP project price mode typologies: a China-based comparative case study

PurposePublic–Private Partnerships (PPPs) are crucial to the procurement of global infrastructure projects. Moreover, a price mode based on a cluster of core concessionary items is key to the delivery of value-for-money and successful project outcomes. However, existing research has yet to fully identify PPP concessionary items, nor yet described the range of practical price modes. This study provides taxonomy of core concessionary items impacting PPP projects, systematically classifies price modes, and assesses the applicability and risk impacts of those price modes on PPP projects.Design/methodology/approachThis study adopts a comparative case study method in analyzing core concessionary items and alternative price modes. China is taken as the context, as it is one of the world’s largest PPP markets. In ensuring research validity and reliability, diverse data sources are utilized, with a graphic content analysis tool developed to capture the structure of price modes.FindingsEight PPP price modes are identified. These are: (1) UP (Unit Price) mode, (2) ALS (Annual Lump Sum) mode, (3) IRR (Internal Rate of Return) mode, (4) RP (Return for Investing Capital (RIC) - Profit Rate of O&M (PROM)) mode, (5) RFP (RIC - Financing Interest Rate (FR) - PROM) mode, (6) RFPL (RIC - FR - PROM - Lower Limit of User Charge (LLoUC)) mode, (7) RFL (RIC - FR - Lump Sum/Fixed Unit Price O&M Contract (LSOM/FUP)) mode, and (8) RFLL (RIC - FR - LSOM/FUP - LLoUC) mode. Other main findings are as follows: (1) Five risk allocation configurations can be achieved via these price modes. Yet while different price modes enable the allocation of specific risks, these do not always align with contracting parties’ original intentions. (2) IRR and RP modes may be less applicable in general because of their vulnerability in allocating critical risks and capacity for spurring opportunistic behavior.Originality/valueBy depicting the paths by which concessionary items in price modes affect cash flow, a systematic analysis of price modes was conducted exposing structural characteristics, along with risk allocation choice implications. The study is unique in: (1) Providing a systematic classification of PPP price modes used in PPP projects, (2) Presenting a comprehensive identification and streamlining of concessionary items in PPP practice, and (3) Analyzing the risk effects of different price modes. Together, these outcomes offer a hitherto unavailable perspective on PPP project risk management. The value of the study lies in the following: (1) Existing studies employ diverse concessionary items, but their applicability varies. This study offers an overarching framework facilitating decision-making in selecting appropriate PPP price modes and in determining concessionary items. (2) This study adds to the understanding of PPP price modes in significant ways that will aid local governments and potential sponsors in crafting and administrating more workable contract designs

Comparison of TSEP Performances Operating at Homogeneous and Inhomogeneous Temperature Distribution in Multichip IGBT Power Modules

Temperature Sensitive Electrical Parameters (TSEPs) are used to determine the chip temperature of a single-chip IGBT power module by measuring one electrical device parameter. Commonly, most TSEPs have a linear relationship between the chip temperature and the electrical parameter. Like any sensor, preferred attributes of TSEPs include good accuracy, linearity, and sensitivity. For multichip Insulated Gate Bipolar Transistors (mIGBTs) modules, these can only be achieved when all chips have the same temperature. Equal chip temperatures among different semiconductor chips can be achieved when placing mIGBTs in environmental chambers to produce a homogeneous temperature distribution (HTD). In real applications, however, mIGBTs are power cycled and are exposed to inhomogeneous temperature distribution (ITD) where temperature differences exist between chips. Consequently, measuring one electric parameter only cannot represent each chip temperature which impacts the TSEP sensitivity, linearity, and accuracy. This paper compares the performance of ten TSEPs applied to a mIGBT module operating at HTD and ITD conditions in order to determine which TSEPs are most suitable for mIGBTs in real applications

Parallel complement network for real-time semantic segmentation of road scenes

Real-time semantic segmentation is in intense demand for the application of autonomous driving. Most of the semantic segmentation models tend to use large feature maps and complex structures to enhance the representation power for high accuracy. However, these inefficient designs increase the amount of computational costs, which hinders the model to be applied on autonomous driving. In this paper, we propose a lightweight real-time segmentation model, named Parallel Complement Network(PCNet), to address the challenging task with fewer parameters. A Parallel Complement layer is introduced to generate complementary features with a large receptive field. It provides the ability to overcome the problem of similar feature encoding among different classes, and further produces discriminative representations. With the inverted residual structure, we design a Parallel Complement block to construct the proposed PCNet. Extensive experiments are carried out on challenging road scene datasets, i.e., CityScapes and CamVid, to make comparison against several state-of-the-art real-time segmentation models. The results show that our model has promising performance. Specifically, PCNet* achieves 72.9% Mean IoU on CityScapes using only 1.5M parameters and reaches 79.1 FPS with 1024×2048resolution images on GTX 2080Ti. Moreover, our proposed system achieves the best accuracy when being trained from scratch

Soil carbon and nitrogen dynamics in the first year following herbicide and scalping in a revegetation trial in south-east Queensland, Australia

During revegetation, the maintenance of soil carbon (C) pools and nitrogen (N) availability is considered essential for soil fertility and this study aimed to evaluate contrasting methods of site preparation (herbicide and scalping) with respect to the effects on soil organic matter (SOM) during the critical early establishment phase. Soil total C (TC), total N (TN), hot-water extractable organic C (HWEOC), hot-water extractable total N (HWETN), microbial biomass C and N (MBC and MBN), total inorganic N (TIN) and potentially mineralizable N (PMN) were measured over 53 weeks. MBC and MBN were the only variables affected by herbicide application. Scalping caused an immediate reduction in all variables, and the values remained low without any sign of recovery for the period of the study. The impact of scalping on HWETN and TIN lasted 22 weeks and stabilised afterwards. MBC and MBN were affected by both herbicide and scalping after initial treatment application and remained lower than control during the period of the study but did not decrease over time. While scalping had an inevitable impact on all soil properties that were measured, that impact did not worsen over time, and actually improved plant growth (unpublished data) while reducing site establishment costs. Therefore, it provides a useful alternative for weed control in revegetation projects where it is applied only once at site establishment and where SOM would be expected to recover as canopy closure is obtained and nutrient cycling through litterfall commences. © 2014 Springer-Verlag Berlin Heidelberg

Appraisal of 15N enrichment and 15N natural abundance methods for estimating N2 fixation by understorey Acacia leiocalyx and A. disparimma in a native forest of subtropical Australia

Purpose: It is anticipated that global climate change will increase the frequency of wildfires in native forests of eastern Australia. Understorey legumes such as Acacia species play an important role in maintaining ecosystem nitrogen (N) balance through biological N fixation (BNF). This is particularly important in Australian native forests with soils of low nutrient status and frequent disturbance of the nutrient cycles by fires. This study aimed to examine 15N enrichment and 15N natural abundance techniques in terms of their utilisation for evaluation of N2 fixation of understorey acacias and determine the relationship between species ecophysiological traits and N2 fixation. Materials and methods: A trial was established at sites 1 and 2 located at Toohey Forest, Queensland, Australia, a eucalypt-dominated native forest, to examine the determination of BNF using 15N enrichment and 15N natural abundance methods. Toohey Forest is an urban forest and subjected to frequent fuel reduction burns to protect the adjacent properties. Plant physiological status was measured to determine the relationship between physiological and N2 fixation activities. Results and discussion: Both 15N enrichment and 15N natural abundance techniques may be used to estimate N2 fixation of acacia tree species. The estimation of BNF using 15N enrichment was higher than those of the 15N natural abundance method. A grass reference plant, Themeda triandra, as well as tree reference plants provided an appropriate δ15N signal. Potential B values for Acacia spp. between -0. 3‰ and 1. 0‰ provided an acceptable BNF estimation. This suburban forest is located nearby a busy highway leading to N deposition over time with consequent negative δ15N signal. This N deposition may explain the separation between the δ15N signal of the acacias and that of the reference plants which led to the successful use of the 15N natural abundance technique. Acacia leiocalyx demonstrated greater N2 fixation as well as photosynthesis and instantaneous water use efficiency than Acacia disparimma. However, no strong relationship between plant photosynthesis and N2 fixation was observed in this study. A high within-treatment variation may have masked the relationships between plant BNF activities and photosynthesisConclusions: The 15N natural abundance technique is preferred to be used for future studies as it is simple and inexpensive compared with 15N enrichment method. The dependence of both species on BNF at site 2, where fuel reduction burning had not taken place for 8 years, suggests that the frequent burning impoverished the soil, and this has wider implications as higher fire frequencies are to be expected in other Australian ecosystems as a result of global climate change. © 2012 Springer-Verlag

Enhanced Feature Extraction From Assimilated VTCI and LAI With a Particle Filter for Wheat Yield Estimation Using Cross-Wavelet Transform

To further reveal the relationships between different variables and yield at each growth stage of winter wheat, an approach for estimating regional yields of winter wheat at multiple time scales was developed by assimilating the CERES-Wheat model simulations and remotely sensed observations. Specifically, the particle filter assimilation algorithm was chosen to assimilate the simulated soil moisture at the depth of 0-20 cm and leaf area index (LAI) and MODIS retrieved vegetation temperature condition index (VTCI) and LAI. The resonance periods of time series assimilated VTCIs and LAIs at different growth stages of winter wheat with crop yield were analyzed separately using the cross-wavelet transform to determine the variation relationships between the assimilated variables and yield at multiple time scales, and the calculated weights of assimilated VTCI and LAI at each growth stage of winter wheat were used to establish a yield estimation model. Both assimilated VTCI and LAI could comprehensively integrate the effects of the CERES-Wheat model simulations and remotely sensing observations, and cross-wavelet transformed time series VTCIs and LAIs at each growth stage had specific resonance periods with the time series yields, regardless of whether they were assimilated or not. Compared with the unassimilated variables, assimilated VTCI and LAI were given greater weights at the key growth stages, namely VTCI at the jointing and heading-filling stages and LAI at the heading-filling and milk maturity stages, enhancing feature extraction and the accuracy of yield estimation was improved.</p