Complex Terrain Conditions Research Articles

A novel forestry chassis with an articulated body with 3 degreesof freedom and installed luffingwheel-legs

One of the challenging problems in the forest industry is to develop a chassis that is well-adapted to the complex terrain conditions in the forest. In this article, a novel forestry chassis with an articulated body with 3 degrees of freedom and installed luffing wheel-legs (FC-3DOF&LW) is proposed, and the mechanical model of the luffing wheel-leg is built. Based on the mechanical model, the hydraulic cylinder velocity that involves the wheel-leg luffing is calculated. The process of surmounting the obstacle is presented by multi-body dynamics simulation. To demonstrate the improvement of ride comfort, the other simulation of the chassis with an articulated body with 3 degrees of freedom (FC-3DOF) is contrasted in multi-dynamics software. The final result shows that curves of barycenter displacement for FC-3DOF&LW with the front and rear frames are well matched when the front frame surmounts the obstacle; in particular, the barycenter displacement is almost stable when the rear frame surmounts the obstacle. The maximum rotated angle of the articulated joint reaches almost 37° without the luffing wheel-leg, whereas it is only 4° with FC-3DOF&LW, a decrease of 89.1%. Moreover, the acceleration trend for FC-3DOF&LW is more stable than that for FC-3DOF.

Investigation and evaluation of mountain torrent disasters in Yunnan Province, China

Yunnan Province is at the border of southwestern China, and mountains account for 84% of its land area, with complex terrain and geological conditions. Affected by human activities and other factors, it is prone to floods, debris flows, landslides and other mountain torrent disasters in storm events. This paper describes the necessity for recent surveys of mountain flood disasters. According to such a survey, the prevention and control area of mountain torrent disasters is 188,974 km2, with 175.7 million hm2 of cultivated land and 969,000 houses. There were 4,073 torrential disasters, and 2,608 mountain torrent ditches in need of control in the prevention and control area.

Sensitivity studies of the forth-generation regional climate model simulation of dust storms in the Sistan plain, Iran

Dust storm phenomenon is one of the main features over the Sistan plain, eastern Iran. To examine of dust storm structure in the Sistan area, an experiment was conducted by forth-generation regional climate model in an area between 20°–48°N and 42°–78°E during the cold period of 2000 and 2002 years with two horizontal resolutions (20 and 80 km) in 6-h time step. Validation of satellite data and NCEP/NCAR re-analysis were used to stimulate model outputs. In order to have information pertaining to the dust storms, model is coupled with chemical scheme of the atmosphere, showing dust emission based on various factors. There is a systematic underestimation of dust emission especially over Sistan plain when compared with analyzed data in 80 km. However vectors and streamlines show the same direction in both resolutions but they are show better and near the fact in 20 km horizontal grid spacing compared with NCEP/NCAR re-analysis results, while 20 km will be shown the complex-terrain conditions in studied region. An additional experiment was showed that by using different resolutions and running model to calculate the dust storm factors over the Sistan plain, in 20 km resolution all land surface coverage and functions are better than 80 km resolution and this feature affected on the model outputs. This item led to obtain a clear insight regarding to dust storms when it is indicated in wind velocity cross section and sea level pressure while they are influenced by the Sistan situation.

Assessment of Muscular Fatigue with Electromyography on Lower Back and Leg Muscles during Continuous Uphill and Downhill Load Carriage Task

<p>Soldiers of Indian Army need to carry moderate to heavy load in complex terrain conditions as their routine activity, which may prove to be highly tiring for leg and back muscles. Soldiers’ regular movement at hilly area was simulated in a study consisting of a continuous uphill (UH) and downhill (DH) load carriage task to monitor state of fatigue at back and lower limb muscles. Twelve Indian soldiers walked at a fixed speed on five UH and five DH gradients with three loads (0, 10.7 kg and 21.4 kg). Electromyographic (EMG) recording was carried out throughout the experimentation on four groups of muscles- left and right Erector spinae (ESR and ESL), Vastus medialis (VMR and VML), Gastrocnemius medialis (GMR and GML), and Soleus (SOR and SOL) muscles. Median frequency (MDF) responses of tested muscles were derived from raw (EMG) data. Higher level of muscle fatigue was observed at highest UH inclination as the MDF response in GMR, GML and VMR was lowest at this point. The MDF response were found to be lower at DH gradients as the physical demand of that stage is less than the UH gradients.</p>

Analysis on Tidal Channels Based on UAV Photogrammetry: Focused on the West Coast, South Korea Case Analysis

ABSTRACT Lee, J.K.; Lee, I., and Kim, J.O., 2017. Analysis on tidal channels based on UAV photogrammetry: Focused on the west coast, South Korea case analysis. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 199–203. Coconut Creek (Florida), ISSN 0749-0208. In the coastal waters of the Republic of Korea, the incidence of marine vessel accidents has been increasing in recent years, due to increased maritime traffic and complex terrain conditions. With the proliferation of marine leisure activities and the maritime conditions such as tides, rocks, typhoons, tsunamis, there are various types of marine accidents that have not been experienced before. Therefore, it is imperative to establish an information based system (like digital map or 3D distribution map) that can be utilized in marine safety fields such as accident and disaster prevention. In this investigation, it will be discuss...

Evaluation of Two ANN Approaches for the Wind Power Forecast in a Mountainous Site

Accurate wind power forecast is very important in order to construct smart electric grids. Nevertheless, this task still constitutes a challenge because wind is a very variable and local phenomenon. It is difficult to downscale information coming from Numerical Weather Prediction (NWP) models down to wind farm level and this is especially true onshore, in complex terrain conditions. Artificial Intelligence often comes at hand, for its power in learning what is hidden inside data: Artificial Neural Networks (ANN) are therefore commonly employed for wind power forecast. In this work, a pure ANN method is compared against a hybrid method, based on the combination of ANN and a numerical method based on physically-consistent assumptions (Computational Fluid Dynamics). Both approaches are validated against the SCADA data of a wind farm sited in Italy in a very complex terrain. It arises that the two methods have overall similar performances on average. However, pure ANN turns out to forecast better at mid-energy levels and during cut-off events at the highest wind speed, whereas the hybrid method forecasts better during low and high wind speed ranges. This makes the two approaches complementary and promising for future applications through an ensemble strategy.

Transient measured impedance‐based protection scheme for DC line faults in ultra high‐voltage direct‐current system

DC line fault is a major threat to the security of ultra high-voltage direct-current system due to complex terrain and terrible weather conditions over long distances. This study proposes a DC line backup protection method on the basis of transient measured impedance (TMI), which is defined as the ratio of transient voltage and transient current at both sides of DC line. The characteristics of TMIs are theoretically analysed for DC line faults and external faults, and these characteristics are used to construct a protection scheme. Since the TMIs only depend on the system structure, the proposed method is able to identify the faults correctly, unaffected by the fault resistance and DC line attenuation. A selection method for the faulted line is also proposed based on the ratio of transient component on the bipolar lines. Comparison with the transient-component-based protections and conventional protections demonstrates the promising performance of the proposed protection. Numerous simulations on PSCAD/EMTDC platform and the tests with field fault-recording data have validated the effectiveness of the proposed protection scheme.

Analysis on Slope Stability of Open Pit Coal Mine Based on Grey Support Vector Machine

Shenhua BaoRi XiLe open-pit coal mine slope is located in the seismic belt of hulunbuir prairie in Inner Mongolia, which belongs to the high frequency and intensity earthquake zone, with rainfall concentrated, poor geological distribution, under the influence of complex environmental factors, extremely easy to cause landslide. This paper uses grey model and support vector machine (SVM) to establish slope model, and carries out stress and strain characteristics under the condition of natural, rainfall, earthquake and calculation and analysis of stability. Through the experiment, it analyzes the stability coefficient of downhill under rainfall condition, and obtains the different strength reduction of safety factor list. At the same time, give full consideration to the uncertainty of the earthquake, assume a variety of working conditions of the earthquake, it conducts dynamic analysis of the slope in detail, and gets the dynamic characteristics curves of the monitoring points. Results show that, relative complex terrain conditions, climate conditions and at a high intensity earthquakes area, are the main factors to induce landslides in this region. Therefore, this paper provides a reliable basis for further study of the effects of rainfall and earthquake on slope and disaster prevention and mitigation.

The Technique of Segmental Pigging Process for Long Distance Pipeline of Oil and Gas in China

Worldwide, the pipeline mileage has increased dramatically since 1948 when the industry began to keep mileage statistics for pipeline construction, especially in China. Before operating long distance oil and gas pipelines, the pressure testing for tightness and strength is of great importance for ensuring operating safety. Water is used as service fluid for the pressure testing due to its safety, and long distance pipeline is divided into a number of small sections according to complex terrain conditions. Segmental water pressure testing is now very frequently used in the oil and gas industry, ensuring safety and efficient construction of pipelines. However, some new problems may arise, in practice, for the pigging process, following water pressure testing. Based on the review of previous papers about pipes accidents, the causes can be classified into hydraulic and nonhydraulic aspects. With the method of characteristic (MOC) and basic theory of gas–liquid two-phase unsteady flow, a mathematical model is developed to simulate the hydraulic transients during the pigging process. The model has been applied to some segmental pipes in China to predict varying pressures under complex terrain conditions. Pressure pulses predicted at the end of pigging in the numerical results have also been found to occur in field trials. The analysis shows that pressure pulses may cause overpressure accidents due to vapor cavity collapse. The techniques in this paper can give reasonable instructions in long distance pipeline constructing, promoting the development of Chinese oil and gas industry.

A robust approach for tree segmentation in deciduous forests using small-footprint airborne LiDAR data

This paper presents a non-parametric approach for segmenting trees from airborne LiDAR data in deciduous forests. Based on the LiDAR point cloud, the approach collects crown information such as steepness and height on-the-fly to delineate crown boundaries, and most importantly, does not require a priori assumptions of crown shape and size. The approach segments trees iteratively starting from the tallest within a given area to the smallest until all trees have been segmented. To evaluate its performance, the approach was applied to the University of Kentucky Robinson Forest, a deciduous closed-canopy forest with complex terrain and vegetation conditions. The approach identified 94% of dominant and co-dominant trees with a false detection rate of 13%. About 62% of intermediate, overtopped, and dead trees were also detected with a false detection rate of 15%. The overall segmentation accuracy was 77%. Correlations of the segmentation scores of the proposed approach with local terrain and stand metrics was not significant, which is likely an indication of the robustness of the approach as results are not sensitive to the differences in terrain and stand structures.

The spatiotemporal patterns of rainfall erosivity in Yunnan Province, southwest China: An analysis of empirical orthogonal functions

Rainfall erosivity (R) influences the formation mechanisms and succession processes of soil erosion. Knowing of the R factor facilitates the prediction of soil erosion and of the impact of climate change on erosion. However, defining of the R factor is challenging because its spatiotemporal variation can be complex. We combined the Empirical Orthogonal Function (EOF), North criteria, and Mann-Kendall test (M-K) to investigate the spatiotemporal patterns of the R factor for a study area in a typical mountain plateau region of Yunnan Province (YP), China. Daily rainfall records from 1960 to 2012 were collected from 115 national meteorological observation stations in YP. Based on the daily rainfall erosivity estimating model, we determined that the average annual R factor was 4383.85MJ·mm·ha−1·h−1, the seasonal R factor exhibited an order of summer>autumn>spring>winter, and the summer R was significantly higher than winter R. The spatiotemporal variation of the R factor was complex and did not reveal a uniform pattern. The spatial distribution revealed that the annual and seasonal R factors in the west were higher than those in the east, and R in the south were higher than those in the north. The temporal trends of annual, summer, and autumn R factors had decreasing trends from 1960 to 2012. On the contrary, the spring and winter R factors showed an increasing trend. The EOF analysis identified two typical spatiotemporal patterns of the annual R factor in YP, and three for spring, summer, autumn, and winter R factors. These patterns represented the influence of the monsoon, circulation systems, and complex terrain conditions on the rainfall in the YP.

Coupled on-site measurement/CFD based approach for high-resolution wind resource assessment over complex terrains

Wind resource assessment is essential for development of wind energy, particularly in the regions with complex terrains. This study proposes a coupled on-site measurement/CFD (Computational Fluid Dynamics) based approach to reproduce the spatial variability of wind speed for a region with complex terrain conditions. A complete framework is presented for wind resource assessment, which involves on-site measurement, CFD simulations and statistical analysis. Next, a case study on wind resource assessment for an offshore island with complex terrain features where is equipped with anemometers for long-term wind measurement is performed using the developed approach. The microscale effects in the assessment region are justified from CFD simulations with modified RNG k–ε model. A cross-validation of the numerical simulations against wind tunnel experimental results and on-site measurements indicates a good agreement. Consequently, a detailed wind resource map of the offshore island is attained through the wind data from a single measurement site combined with the CFD simulations, which is of great use for future wind farm siting and turbine micro-siting. The coupled on-site measurement/CFD based approach is expected to enable the efficient and reliable wind resource assessment and facilitate the wind energy development in the areas with complex terrain conditions.

Predicting and Controlling Nuclear Accident Hazards: Issues and Challenges

ABSTRACTGlobal nuclear security is threatened by nuclear accidents and the purposeful use of nuclear weapons. Accordingly, atmospheric pollution prediction and control for nuclear accidents, including identifying sources in nuclear or radiological incidents, predicting hazards to persons and environments, and optimally controlling accident hazards, are current areas of nuclear security research. Source inversion, hazard prediction, and optimal control are three interrelated key issues for nuclear accident emergencies. Although progress has been made in hazard prediction for nuclear accidents since the 1970s and some source inversion methods were presented after the Fukushima nuclear accident, optimal control methods are rarely reported, source inversion methods are less practical, and prediction accuracy remains unsatisfactory. Thus, novel theories are required for optimal control and source inversion for nuclear accidents, and to develop methods for simulating the influences of radioactive plume dispersion and deposition under complex meteorological and terrain conditions. This work reviews the current progress, uncertainties, and research needs in nuclear security. In addition, a rapid source inversion method based on the Lagrangian model is developed and implemented in a test case. To address future challenges, an innovative architecture for Atmospheric Pollution Prediction and Optimal Control System for nuclear accidents (APPOCS) is proposed, and the perspectives are generalized to promote future research on nuclear accident hazard prediction and optimal control. At this time, forward-looking ideas and revolutionary perspectives are required to foster nuclear security research in the academic community.

Lightning-caused forest fire risk rating assessment based on case-based reasoning: a case study in DaXingAn Mountains of China

Lightning-caused forest fires can cause serious damage to the social economy and public property and even threaten human life. Therefore, lightning-caused forest fire risk rating assessment is very important for forest management agency, because the risk rating assessment results could provide important information to prevent fires and allocate extinguishing resources. The existing forest fire risk rating assessment methods are more difficult for the area with sparse meteorological stations, imperfect lightning monitoring systems and complex terrain conditions. Based on remote sensing data and case-based reasoning principle, this paper proposed a method to overcome the limitations of existing forest fire risk rating assessment methods. The proposed method uses three dynamic and two static indexes to characterize the potential fire environment. The dynamic indexes are temperature condition index, vegetation condition index and water condition index. The static indexes are terrain fluctuation and LIS/OTD lightning density. In DaXingAn Mountains of China, the fire risk rating spatial distribution maps with 8-day cycle before the occurrences of historical lightning-caused fires were produced by using the lightning-caused forest fire risk rating assessment method during 2000–2006 in this paper. The results showed that most of the historical lightning-caused fires occurred in the region with high fire risk rating, and the spatial–temporal distribution changes of the lightning-caused fire risk rating followed the same trend as the changes in the number of lightning-caused fires. Therefore, the lightning-caused forest fire risk rating assessment method proposed in this paper could assess the fire risk rating effectively, and this method could also provide a reference for other countries and regions with sparse meteorological stations and imperfect lightning monitoring systems.

Организационно-технологические особенности использования древесного сырья полученного от рубок промежуточного пользования в буковых лесах Большого Кавказа

In the farms of the north-eastern slope of the Greater Caucasus wood raw material obtained from intermediate felling, is not fully utilized and is not effective, due to the organizational and technical difficulties of farms. In addressing these issues in 8 directions of the region with a length of 40-50 km 14 intermediate assembly points were organized, which are intended for the collection and temporary storage of wood raw material harvested within a radius of 15-20 km of the forest. Need to establish assembly points is due to the complexity of relief items and the possibility of year-round use of the main roads of regional importance. To ensure uninterrupted timber industry and in full at the assembly point accumulated wood raw material is partially sorted. Processing of harvested wood raw material is planned for timber industry, located near the central region of the main road in the territory of Cuba town. Establishment in the area of the complex is considered justified, since the resource base in the coming years for intermediate, and later for the main use will be more than 100 thousand hectares of forests in the region. In the proposed area for the industrial complex for processing of raw wood there are all the technical and economic prerequisites. Accumulated in the assembly points wood raw material to the point of processing is transported using self-loading lumber carriers of up to 8 meters length, which is associated with a complex terrain conditions and road network in the region. This complex is planned to organize the following process areas: sawmills, parquet and packaging, small-chip technology, processing of technical greenery. In organizing the production sites size and quality characteristics and volumes of each category of harvested wood raw materials are taking into account, as well as the need for forest products in the region and the country as a whole. In the processes it is envisaged to use the most advanced modular processing of wood with the release of standard lumber, wood workpieces of different products, pulp chips, wood greens and products of its processing.

Technology and Management Innovation of the Construction of the Golden Gate Bridge in San Francisco

The Golden Gate Bridge in San Francisco was built in 1937 and is nearly eighty years old. It made many breakthroughs in its building and operation management, which opened up a new chapter of engineering innovation. However, initially, it was thought to be a "mission impossible" . In addition to the technical barriers including complex terrain conditions and longer span, some management barriers such as money and time limit for a project blocked its success. How did it break through the technical barriers and management barriers and realized technology and management innovation? This paper explores the background of the bridge’s planning, construction and operation, tries to solve the question of how the innovations were made, and finds out its inspirational significance for today's engineering innovation. Eventually the paper finds that public participation, scientific management and integration innovation played an important role in its success, and how it overcame barriers to reach innovation is worth learning.

Influence of complex topography on global solar radiation in the Yangtze River Basin

Global solar radiation (GSR) is the most direct source and form of global energy, and calculation of its quantity is highly complex due to influences of local topography and terrain inter-shielding. Digital elevation model (DEM) data as a representation of the complex terrain and multiplicity condition produces a series of topographic factors (e.g. slope, aspect, etc.). Based on 1 km resolution DEM data, meteorological observations and NOAA-AVHRR remote sensing data, a distributed model for the calculation of GSR over rugged terrain within the Yangtze River Basin has been developed. The overarching model permits calculation of astronomical solar radiation for rugged topography and comprises a distributed direct solar radiation model, a distributed diffuse radiation model and a distributed terrain reflectance radiation model. Using the developed model, a quantitative simulation of the GSR space distribution and visualization has been undertaken, with results subsequently analyzed with respect to locality and terrain. Analyses suggest that GSR magnitude is seasonally affected, while the degree of influence was found to increase in concurrence with increasing altitude. Moreover, GSR magnitude exhibited clear spatial variation with respect to the dominant local aspect; GSR values associated with the sunny southern slopes were significantly greater than those associated with shaded slopes. Error analysis indicates a mean absolute error of 12.983 MJm−2 and a mean relative error of 3.608%, while the results based on a site authentication procedure display an absolute error of 22.621 MJm−2 and a relative error of 4.626%.

Research on Geometric Layout of Pseudo-Satellite in the Small Airport

Because complex terrain conditions, the small airport satellite navigation signal being blocked, while reducing the positioning accuracy of the approach and landing segment, but also increase the operating costs of the small airport. This paper through independent pseudo-satellite network, from PDOP (Position Dilution of Precision) and VDOP (Vertical Dilution of Precision) studied several layout of airport pseudo-satellites. Through simulation show that the geometric layout of the pseudo-satellite can improve positioning accuracy of approach and landing segment in the small airport and reduce the DOPs, ​​provide reference for practical engineering applications.

A Study on the Highway Alignment Method

By applying the model in a case, two methods of linear and curved alignment are analyzed and compared. Besides, the main existing problems and the solutions to solve them are studied. The results show that curved alignment method has obvious advantages in highway design, interchange design, and other complex terrain conditions. With a variety of computer-aided design software line appears, curved alignment method will be widely used.

Planting area estimation of Chinese Tibetan medicine Herpetospermum pedunculosum based on RS&GIS-by case study of Lengqi and Xinglong town in Luding county

The herbs used as the material for traditional Chinese medicine are mostly planted at mountain areas where there is appropriate weather condition. Due to the complex terrain condition in mountain area, the planting at such places is always associated with a scattered pattern, which inevitably bring difficulty to the work of accurate measurement for the planting area. Advanced research about monitoring the planting area for medicine-herb under complex environmental condition is so critical and meaningful for developing the medicine-herb planting to a large scale and an industry. Therefore, this research, taking the planting of Herpetospermum pedunculosum in Luding county as an example, utilizes RS&GIS: using the image data from TM and ETM datum as the remote sensing information source, integrating GPS data from quadrat survey on the spots, and analyzing on a GIS platform, to extract the planting area of H. pedunculosum in Luding county. The results indicate that: (1) the method and technology used to estimate the planting area of H. pedunculosum are feasible and can be applied to monitoring the planting area of medicine-herb at mountain area under complex environmental conditions: (2) the planting area of H. pedunculosum in Luding county is estimated to be 857. 246 acres by the methods utilized in this research, which is closed to the value from local statistical data with an error range less than 5%; (3) in consideration of those inevitable errorrs generating from the procedures such as remote sensing data acquisition, data preprocessing, data interpretation, and so on, and the fact that the classification of remote sensing data, which must be implemented by those above procedures, was used directly to extract the herb type, the accuracy of area estimation for the herb is significantly influenced by the accuracy of classification for herb type, and the estimated area is inevitably associated with some error.