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Pavement performance model for road maintenance and repair planning: a review of predictive techniques

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Digital Transportation and Safety

Digital Transportation and Safety 2023年第4期2卷 253-267页

作者： Krishna Singh Basnet Jagat kumar shrestha Rabindra Nath shrestha Department of Civil Engineering Pulchowk CampusInstitute of EngineeringTribhuvan UniversityKathmanduP.O.Box 1915Nepal

This paper provides a review of predictive analytics for roads,identifying gaps and limitations in current methodologies.It explores the implications of these limitations on accuracy and application,while also discussing how advanced predictive analytics can address these challenges.The article acknowledges the transformative shift brought about by technological advancements and increased computational capabilities.The degradation of pavement surfaces due to increased road users has resulted in safety and comfort issues.Researchers have conducted studies to assess pavement condition and predict future changes in pavement structure.Pavement Management Systems are crucial in developing prediction performance models that estimate pavement condition and degradation severity over time.Machine learning algorithms,artificial neural networks,and regression models have been used,with strengths and weaknesses.Researchers generally agree on their accuracy in estimating pavement condition considering factors like traffic,pavement age,and weather conditions.However,it is important to carefully select an appropriate prediction model to achieve a high-quality prediction performance system.Understanding the strengths and weaknesses of each model enables informed decisions for implementing prediction models that suit specific needs.The advancement of prediction models,coupled with innovative technologies,will contribute to improved pavement management and the overall safety and comfort of road users.

关键词： Road Maintenance Prediction Model Deterministic Model Probabilistic Model Machine Learning Model

Determining bioclimatic space of Himalayan alder for agroforestry systems in Nepal

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Plant Diversity 2018年第1期40卷 1-18页

作者： Santosh kumar Rana Hum Kala Rana Krishna kumar shrestha Suresh Sujakhu Sailesh Ranjitkar Key Laboratory{or Plant Diversity and Biogeography of East Asia Kunming Institute of BotanyKunming 650201China University of Chinese Academy of Sciences Beijing 100049China Systematics and Biodiversity Unit Central Department of BotanyTribhuvan UniversityKirtipurKathmanduNepal jade Consult Private Limited KabilmargThapathaliKathmanduPOB 746Nepal World Agroforestry Centre East and Central Asia 132 Lanhei RdHeilongtanKunmingChina

Himalayan alder species are proven to be very useful in traditional as well as contemporary agroforestry practice. These nitrogen-fixing trees are also useful in the land restoration. Therefore, understanding the distribution of Himalayan alder and the potential zone for plantation is meaningful in the agroforestry sector. Suitable climatic zones of Alnus spp. were modelled in Max Ent software using a subset of least correlated bioclimatic variables for current conditions(1950 -2000), topographic variables(DEM derived) and Landuse Landcover(LULC) data. We generated several models and selected the best model against random models using ANOVA and t-test. The environmental variables that best explained the current distribution of the species were identified and used to project into the future. For future projections, ensemble scenarios of climate change projection derived from the results of 19 Earth System Models(ESM) were used. Our model revealed that the most favorable conditions for Alnus nepalensis are in central Nepal in the moist north-west facing slope, whereas for Alnus nitida they are in western Nepal.The major climatic factor that contributes to Alnus species distribution in Nepal appears to be precipitation during the warmest quarter for A. nepalensis and precipitation during the driest quarter for A. nitida. Future projections revealed changes in the probability distribution of these species, as well as where they need conservation and where they can be planted. Also, our model predicts that the distribution of Alnus spp. in hilly regions will remain unchanged, and therefore may represent sites that can be used to revitalize traditional agroforestry systems and extract source material for land restoration.

关键词： Alder Agroforestry Species distribution modeling Climate change MaxEnt

A Galeazzi-variant type fracture-dislocation in adults

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Chinese Journal of Traumatology 2013年第6期16卷 344-346页

作者： Raju Vaishya Sundar kumar shrestha Abhishek Vaish Department of Orthopaedics Indraprastha ApolloHospitals New Delhi India Department of Orthopaedics & Rehabilitation SanchetiHospital Pune India

有在近似或远侧的桡尺骨的关节(DRUJ ) 的脱臼任何一个的半径或尺骨的 ObjectiveFracture 不是普通损害并且内在地是不稳定的。这里，我们报导一个案例系列，与与 DRUJ 的脱臼联系的两个骨头前臂破裂，作为 Galeazzi 变体的类型破裂脱... 详细信息

有在近似或远侧的桡尺骨的关节(DRUJ ) 的脱臼任何一个的半径或尺骨的 ObjectiveFracture 不是普通损害并且内在地是不稳定的。这里，我们报导一个案例系列，与与 DRUJ 的脱臼联系的两个骨头前臂破裂，作为 Galeazzi 变体的类型破裂脱臼，并且试着分析学习基于 6 个病人有的这损害 pattern.MethodsThe 不同年龄(20 ～ 45 年) 的 Galeazzi 变体的类型破裂脱臼。所有破裂是关上的类型。二破裂包含了一样的水平，三破裂在半径和尺骨柄的不同层次。在彻底的检查和调查以后，他们与有限接触被对待没有为 DRUJ.ResultsAll 案例的另外的固定的动态压缩板被跟随在上面为 24 个星期。最大的发生发生在在 31 和 40 年之间的年龄组。半径和尺骨的所有破裂在 12 个星期的平均时间被统一。在最后的后续的手腕和肘，旋后和内转的运动的范围是正常的。没有在任何在成年人的 cases.ConclusionGaleazzi 变体的 DRUJ 的随后的 re-subluxation 或脱臼是有手腕损害的前臂的一个新 undescribed 模式。稳定的开的减小和两个骨头前臂破裂的内部固定是强制的，为破坏 DRUJ 愈合在一个演员组到 3 ～ 4 星期固定列在后面。

关键词：骨折内固定变型成人 RADIUS 损伤模式平均时间运动范围不稳定

A high-resolution optically addressed spatial light modulator based on ZnO nanoparticles

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Light(Science & Applications) 2015年第1期4卷 470-476页

作者： Pawan kumar shrestha Young Tea Chun Daping Chu University of Cambridge Cambridge CB30FAUK

An optically addressed spatial light modulator(OASLM)can modulate the wavefront of a read light by displaying a phase pattern or a hologram configured by the intensity distribution of a write light.Using ZnO nanoparticles(NPs)as a novel photoconductor,a high-resolution OASLM was fabricated.A ZnO NP suspension was spin-coated on an indium tin oxide(ITO)-coated glass substrate and annealed to form a photosensitive layer.The device was characterized electrically and optically.The device was operated at low driving voltages in the transmission mode.Updatable recording of a diffraction grating up to 825 lp mm^(-1) with a diffraction efficiency(DE)of 0.05%and binary holograms with pixel sizes from 2 mm down to 0.72 mm were demonstrated using a 405 nm wavelength write laser and a 635 nm wavelength read laser.

关键词： holography nanoparticles OASLM ZnO

Critical visceral adipose tissue thresholds aassociated with type 2 diabetes mellitus in chinese population

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Journal of Nanjing Medical University 2007年第1期21卷 15-20页

作者： Om kumar shrestha Department of Radiology the First Affiliated Hospital of Nanjing Medical University Nanjing 210029China

To compare intervertebral location L2-L3 with L4-L5 as landmarks for measuring abdominal fat distribution and to determine critical levels of visceral adipose tissue （VAT） at those planes, exceeding which may lead to the development of type 2 diabetes. Methods： Abdominal fat distribution was measured using computed tomography（CT） in 29 diabetics （19 male, 10 female） and 30 non-diabetics （18 male, 12 female）. CT images obtained at two intervertebral locations L2-L3 and L4-L5 were used to measure the areas of total fat, VAT and subcutaneous adipose tissue （SCAT） using slice thickness of 5mm and an attenuation range from -190 to -30 Hounsfield units （HU）. Data were analyzed using logistic regression and Receiver-operating characteristic （ROC） analysis. Results： At L2-L3, diabetes and obesity were correctly classified at 91.53% and 83.05% respectively, while at L4-L5, the same were correctly classified at 84.75% and 88.14% respectively. VAT compared to SCAT, had significantly higher correctly classified percent values for predicting diabetes in both measurement sites. At L2-L3, VAT≥177.29 cm2 or VAT ≥51.52% of the total fat area had the highest correctly classified value for predicting diabetes in men, while VAT ≥ 132.27 cm2 or VAT≥45.7% of the total fat area had the highest correctly classified value for predicting diabetes in women. At LA-L5, VAT≥ 130.82 cm2 or VAT≥45.5,$% of the total fat area had the highest correctly classified value for predicting diabetes in men, while VAT≥ 118.56 cm2 or VAT≥32.24% of the total fat area had the highest correctly classified value for predicting diabetes in women. Conclusion： L2-L3 plane is a better landmark for measuring abdominal fat distribution for predicting diabetes, while abdominal fat distribution measured at L4-L5 has better association with obesity. Regardless of the measurement site, VAT compared to SCAT, has significantly stronger association with diabetes.

关键词： visceral adipose tissue type 2 diabetes measurement computed tomography

Long Lead-Time Streamflow Forecasting Using Oceanic-Atmospheric Oscillation Indices

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Journal of Water Resource and Protection 2014年第6期6卷 635-653页

作者： Niroj kumar shrestha Department of Agriculture and Biological Engineering University of Florida Immokalee USA

Climatic variability influences the hydrological cycle that subsequently affects the discharge in the stream. The variability in the climate can be represented by the ocean-atmospheric oscillations which provide the forecast opportunity for the streamflow. Prediction of future water availability accurately and reliably is a key step for successful water resource management in the arid regions. Four popular ocean-atmospheric indices were used in this study for annual streamflow volume prediction. They were Pacific Decadal Oscillation (PDO), El-Nino Southern Oscillation (ENSO), Atlantic Multidecadal Oscillation (AMO), and North Atlantic Oscillation (NAO). Multivariate Relevance Vector Machine (MVRVM), a data driven model based on Bayesian learning approach was used as a prediction model. The model was applied to four unimpaired stream gages in Utah that spatially covers the state from north to south. Different models were developed based on the combinations of oscillation indices in the input. A total of 60 years (1950-2009) of data were used for the analysis. The model was trained on 50 years of data (1950-1999) and tested on 10 years of data (2000-2009). The best combination of oscillation indices and the lead-time were identified for each gage which was used to develop the prediction model. The predicted flow had reasonable agreement with the actual annual flow volume. The sensitivity analysis shows that the PDO and ENSO have relatively stronger effect compared to other oscillation indices in Utah. The prediction results from the MVRVM were compared with the Support Vector Machine (SVM) and the Artificial Neural Network (ANN) where MVRVM performed relatively better.

关键词： Oscillation Indices Streamflow Lead-Time Prediction

Generation of Synthetic Ground Motion

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Journal of Geological Resource and Engineering 2018年第3期6卷 105-111页

作者： Hari Ram Parajuli Rajesh kumar shrestha Dept.of Civil Engineering Pulchowk CampusTribhuwan UniversityNepal Dept.of Civil Engineering Thapathali CampusTribhuwan UniversityNepal

The main target of the study is to generate artificial earthquake time histories which are compatible with real earthquakes.A simple frequency-domain method for generating time histories from the given response spectrum is presented in this research.Weighted average response spectra are generated using three attenuation relationships developed for the subduction zonesuitable for Barpak M7.8 earthquake records at TU,Kirtipur.The ground motions are simulated with consideration of source,site,and path.The simulation work is started from noise generation work with windowing,Fast Fourier Transform(FFT)and spectra matching(target and generated)to obtain simulated time history using MATLAB programming language.Simulated ground motions can be utilized as input ground motions for the dynamic analysis and design of new structures as well as retrofitting of existing structures.

关键词： Artificial earthquake weighted average response spectrum attenuation relationship Barpak Fast Fourier Transform

Variation in Plant Functional Traits along Altitudinal Gradient and Land Use Types in Sagarmatha National Park and Buffer Zone, Nepal

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American Journal of Plant Sciences 2019年第4期10卷 595-614页

作者： Srijana Shah Krishna kumar shrestha Christoph Scheidegger Department of Plant Resources National Botanical Garden Kathmandu Nepal Central Department of Botany Tribhuvan University Kathmandu Nepal Ethnobotanical Society of Nepal (ESON) Kathmandu Nepal Swiss Federal Institute of Forest Snow and Landscape Research (WSL) Birmensdorf Switzerland

Functional traits are predictors of plants in response to environmental stimuli. They represent specific functional adaptations to various environmental stresses. This study deals with the variation in plant functional traits along elevation gradient and land-use types in Sagarmatha National Park and Buffer Zone, Nepal. Two field investigations in April and September, 2011 were made to collect samples. Sampling was done from 2200 - 3800 m asl varying approx. 400 m. East and west facing aspects of each valley were chosen. In each aspect four land-use type categories including disturbed (cultivated land, exploited forest and meadow) and less disturbed natural forest were selected. A transect of 25 m long and 2.5 m wide was laid. Different eight traits of plants including lifeform, plant height, clonality, spinescence, leaf dry matter content, stem specific density, twig dry matter content and twig drying time were examined for 60 plant species belonging to 31 families, collected from 40 sampled plots. Nine different types of growth forms were recorded. Plant height of the investigated species ranged from 0.03 - 15 m. The stolon consisting species were dominant in exploited forests. Diversity of clonal species was more in meadow and non-clonal species were dominant in all the altitudes. Only eight species consisted of spines. In the disturbed land-use categories, we found high variation in a particular trait. Correlation analyses revealed the significant relationship (p < 0.01) among different traits. Herbs and shrubs were dominant at higher elevation and in disturbed land-use categories. Species from high altitude were mostly short basal herbs, while spinescence and tall trees were observed at lower altitudes. Species recorded in meadows and exploited forests showed high variation in traits due to disturbance mainly grazing, fire, litter collection and trampling. Altitudinal variation, climatic conditions and disturbance most strongly influence trait expression in the study area.

关键词： Functional Traits Altitudinal Gradient Land-Use Types Disturbances

组织多普勒评价心衰患者左心室的非同步运动与QRS间期的关系

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组织多普勒评价心衰患者左心室的非同步运动与QRS间期的关系

作者： Sanjaya kumar shrestha 郑州大学

学位级别：硕士

目的：评价心衰患者左心室非同步运动与QRS间期的关系。方法与结果：选择26例严重左心衰（LVEF≤35％）患者进行超声心动图及组织多普勒（TDI）的测量，其中，QRS间期正常的18例患者作为A组，QRS间期延长（＞120ms）或左束... 详细信息

目的：评价心衰患者左心室非同步运动与QRS间期的关系。方法与结果：选择26例严重左心衰（LVEF≤35％）患者进行超声心动图及组织多普勒（TDI）的测量，其中，QRS间期正常的18例患者作为A组，QRS间期延长（＞120ms）或左束支传导阻滞的8例患者作为B组。利用组织多普勒测量左心室12个节段（基底段及中间段各6个）的QRS波起始至心肌收缩期峰值速度的时间，左心室非同步运动阳性限定为：左心室内任何两个节段的达峰时间差=60ms。A组中左心室非同步运动的发生率为72％（13／18），B组中的发生率为87％（7／8），（x~2=0.70，p=0.403）。结果显示两组间12个节段中最大达峰时间差有显著差异（73±36 ms vs 97±38 ms，t=1.54，p=0.136），但两组间心室内的机械延迟（IVMD）无显著差异，左心室的非同步运动与QRS间期无相关性（r=0.29，p=0.146）。伴心室内的机械延迟（IVMD）患者的QRS间期有延迟的趋势，舒张末容积（ESV）和IVMD有正相关（r=0.40，p=0.043），射血分数（EF）和IVMD负相关（r=0.45，p=0.021）。结论：心衰患者的QRS间期可正常或轻微延长，同时可发生左心室的非同步运动。QRS间期代表的电收缩的延迟与组织多普勒测量的左心室内的传导延迟无相关性。TDI用于评价左心室同步运动时优于QRS间期，可作为心脏再同步化治疗的评价指标。

关键词：组织多普勒显像心室内机械延迟收缩不同步 QRS间期