Difficult Terrain Research Articles

Hierarchical Pitch Control for Small Wind Turbines Based on Fuzzy Logic and Anticipated Wind Speed Measurement

Bringing electricity to areas of difficult terrain is a complicated task, so it is convenient to generate power using local natural resources, such as wind, through a small horizontal-axis wind turbine (S-HAWT). However, at the rotor height of these wind turbines, the wind is often turbulent due to obstacles such as trees and buildings. For a turbine to function properly in these conditions, the action of the wind force on the rotor must be smoothed out by controlling the pitch angle. A commercial derivative-integral-proportional (PID)-type pitch controller works well when system dynamics are stable, but not when there are disturbances in the system. This paper proposes a hierarchical fuzzy logic controller (HFLC) to solve the nonlinear system effects produced by atypical winds. The methodology includes a statistical analysis of wind variability at the installation site, which determines the functions of belonging and its hierarchy. In addition, installing an anemometer in front of the turbine allows an advanced positioning of the blades in the presence of wind gusts. The algorithm was implemented in an S-HAWT, and a comparison was made to quantify the performance difference between the proposed control strategy and a conventional PID controller.

MEDUSA: A Multi-Environment Dual-Robot for Underwater Sample Acquisition

Aerial-aquatic robots possess the unique ability of operating in both air and water. However, this capability comes with tremendous challenges, such as communication incompatibility, increased airborne mass, potentially inefficient operation in each of the environments and manufacturing difficulties. Such robots, therefore, typically have small payloads and a limited operational envelope, often making their field usage impractical. We propose a novel robotic water sampling approach that combines the robust technologies of multirotors and underwater micro-vehicles into a single integrated tool usable for field operations. The proposed solution encompasses a multirotor capable of landing and floating on the water, and a tethered mobile underwater pod that can be deployed to depths of several meters. The pod is controlled remotely in three dimensions and transmits video feed and sensor data via the floating multirotor back to the user. The `dual-robot' approach considerably simplifies robotic underwater monitoring, while also taking advantage of the fact that multirotors can travel long distances, fly over obstacles, carry payloads and manoeuvre through difficult terrain, while submersible robots are ideal for underwater sampling or manipulation. The presented system can perform challenging tasks which would otherwise require boats or submarines. The ability to collect aquatic images, samples and metrics will be invaluable for ecology and aquatic research, supporting our understanding of local climate in difficult-to-access environments [Video attachment: https://youtu.be/v4xWmEHUSM4].

Urinalysis Reveals Hemolysis In A World-Class Ultramarathon Runner: A Case Study

PURPOSE: Ultra-endurance running, classified as any distance greater than a marathon (42.2km), is strenuous on the body. These extreme distances may include difficult weather conditions or terrain (e.g., heat, cold, altitude, trails, etc.) and could lead to changes in urine biomarkers resulting from damage to essential organs (e.g., kidney, liver, and heart). The purpose of this study was to determine the effects of running a grueling 161.3km trail race on general characteristics, presence of blood, and other molecules in the urine of an elite ultra-endurance runner (EUR). METHODS: Urine specimens were collected from a 32y male EUR (170cm, 64.5kg, age-ranked 98.7%[ultrasignup.com]), before and after completing the Western States Endurance Run (WSER). Samples were analyzed using 11-parameter urinalysis strips (Med Lab Diagnostics, Laguna Beach, CA) one day pre-race and ~2h post-race. RESULTS: EUR finished the WSER in less than 16 hours. Main findings showed red blood cell (RBC) count increased from 0 to ≥200 cells/μl (indicated hemolysis), bilirubin increased from 0 to 17 mmol/L (biproduct of hemoglobin), and urobilinogen increased from 0 to 3.2 mmol/L (indicated RBC destruction) post-race. Urine proteins and ketone abundance increased while ascorbate decreased post-race. CONCLUSIONS: Elevated urinary levels of red blood cell derivatives post-WSER highlight the formidable hematologic implications of ultramarathon running. Modalities to mitigate this phenomenon as well as an improved understanding of the systemic consequences of and time to recover from this exercise-induced hemolysis are of interest.

Expert System for Diagnosing Skin Disease

The most unpredictable and difficult terrain in the field of medical diagnosis is dermatology. Dermatological diseases are the most prevalent diseases that one out of three men suffer skin disorder. Regardless of being prevalent , diagnosis of these diseases require more experience in domain. About 90 percent of skin disorders can be cured by primary care. This conveys that the early care for the disease is necessary . This early stage detection can be made easier by computer aided diagnosis system. Diagnostic expert-based computer systems that simulate the diagnostic ability of human body and disease. So we propose Expert system which classify skin diseases based on their appearance and its characteristics. Rather than training every diseases in single image classifier model . We categorize skin disease based on their characteristic and train model separately for each category. This system will filter and cleans data and categorize based on their characteristics. Feature extraction and classification using complex methods such as the convolutional neural network(CNN) and softmax classifier. This system will provide more accuracy , fast and efficient result than traditional method.

Time series assessment of the relationship between land surface temperature due to change in elevation: a case study from Hindukush-Himalayan Region (HKH)

Environmental studies that include studies related to climate change, change in biodiversity, and hydrology consider land surface temperature (LST) and near-surface air temperature as significant variables to contribute. In this context, we investigated the time series assessment of the relationship between LST and elevation over the two decades (1995–2017) using remotely sensed (Landsat 5, Landsat 7, Landsat 8, MODIS) and ground weather stations’ datasets. The study area that is Gilgit-Baltistan, northern province of Pakistan in Hindukush and Himalaya Region (HKH), was selected for quantitative analysis in this study as it has high significance in terms of climate change due to presence of very high and large number of mountains and difficult terrain heavily covered with snow and glaciers. To assess the LST, a linear regression model was developed to quantify the significance of key factors affecting it. Our research results show that there exists a strong negative linear relationship (with correlation coefficient of 0.61 on average) for all datasets (remotely sensed and in situ) between LST and elevation and it is consistent over the study period (1995–2017) for both seasons of winter and summer. Further, there is a difference of change in LST for different seasons (average winter and summer difference is 3.0 °C) and for different datasets (Landsat, MODIS, and weather stations’ dataset). There is a greater change in LST for change of elevation in 1000 m vertically as compared to change horizontally. Our results indicate that the change trend in LST from 1995 to 2007 is downward with minor variation, however, this trend changes into upward trend from 2007 to 2017. The comparison of results of remotely sensed and weather stations’ dataset shows that there is a consistency of change in temperature and LST due to change in elevation. However, there is a less difference in summers (0.76 °C) and large difference in winters, i.e., 3.94 °C.

Efficiency drivers in harvesting operations in mixed Boreal stands: a Norwegian case study

ABSTRACT This paper uses Data Envelopment Analysis (DEA) to evaluate how the technical efficiency of forest harvesting operations is influenced by terrain conditions and forest attributes, in addition to exploring the existence of other influencing factors. To this end, 643 shift-level observations of harvesting operations on 253 distinct harvested sites were used. The aim of this study is to highlight the harvester’s ability to maximize the outputs, represented by the number of assortments for various tree species, given inputs such as harvest volume, harvest time for various tree species, and distance traveled by the harvester. Operational environment variables such as harvest, or decision-making unit (DMU) size, shape, and terrain characteristics were included. We found large variations in efficiency scores, and that inefficient harvest operations could theoretically be improved by reducing input by up to ca. 80%. A second stage regression estimation was applied to identify which factors significantly affected inefficiency. It was found that the inefficiency decreases with increasing stem-volume for pine and broadleaves, increasing stand density, and increasing share of pulpwood and non-marketable timber, while it increases with the number of logs produced per tree (in broadleaves). Inefficiency increases also with an increasing ratio of actual travel distance to minimal travel distance. The study shows how adopting DEA methods in forest operations might be used in combining efficiency analysis and environmental factors, by identifying and measuring inefficiency due to, for example, difficult terrain.

LITERATURE REVIEW ON DEVELOPING INDUSTRY IN ETHNIC MINORITY AND MOUTAINOUS AREAS

Ethnic minorities and mountainous areas, especially in developing countries, are often less developed than other regions. Although these areas have quite a lot of mineral resources, forest resources; harsh climates, difficult and inaccessible terrain, combined with political and social marginality certainly contribute to making difficulties in developing economies in general and industry in special. The article summarizes and analyzes previous studies on sustainable development in general, sustainable industrial development in ethnic minority and mountainous areas, in particular, to clarify which contents and issues have been studies and which contents need care for further studies, then a research model was proposed in line with the orientation of developing industry in ethnic minority and mountain areas sustainably.

Using publicly available flight data to analyze health disparities in aeromedical retrieval.

ObjectivesSpecialist healthcare cannot be provided in all locations. Helicopters can help to reduce the inherent geographical inequity caused by long distances or difficult terrain. However, the selective use of aeromedical retrieval could lead to other forms of health disparities. The aim of this project was to evaluate such inequities in access to helicopter transport.MethodsThis was a geospatial analysis of publicly available flight tracking data for 18 emergency medical helicopters in the state of Alabama for a 90‐day period between March 2019 and June 2019. Data are presented as the number of incidents attended per population, by population (total, insured, and uninsured), as funnel plots, by county. This method allows the identification of positive and negative outliers.ResultsWe identified 672 likely scene retrieval flights. Twelve counties were probable (outside of 99% confidence interval [CI]) high outliers (more helicopter retrievals than expected), and 4 were possible (outside of 95% CI) high outliers. There were 5 possible low outliers (fewer helicopter retrievals than expected) and 6 probable low outliers. Analysis by insurance status revealed similar results. However, there was no easily discernible geographic pattern to this variability.ConclusionThere is considerable geographical variability in the number of helicopter retrievals, with no easily discernable pattern. Some of this variability may be due to differences in injury epidemiology, but others may be due to case selection. However, the present data are insufficient to come to firm conclusions, and additional study is warranted.

The effects of reduced-gravity on planetary rover mobility

One of the major challenges faced by planetary exploration rovers today is the negotiation of difficult terrain, such as fine granular regolith commonly found on the Moon and Mars. Current testing methods on Earth fail to account for the effect of reduced gravity on the soil itself. This work characterizes the effects of reduced gravity on wheel–soil interactions between an ExoMars rover wheel prototype and a martian soil simulant aboard parabolic flights producing effective martian and lunar gravitational accelerations. These experiments are the first to collect wheel–soil interaction imagery and force/torque sensor data alongside wheel sinkage data. Results from reduced-gravity flights are compared with on-ground experiments with all parameters equal, including wheel load, such that the only difference between the experiments is the effect of gravity on the soil itself. In lunar gravity, a statistically significant average reduction in traction of 20% is observed compared with 1g, and in martian gravity an average traction reduction of 5–10% is observed. Subsurface soil imaging shows that soil mobilization increases as gravity decreases, suggesting a deterioration in soil strength, which could be the cause of the reduction in traction. Statistically significant increases in wheel sinkage in both martian and lunar gravity provide additional evidence for decreased soil strength. All of these observations (decreased traction, increased soil mobilization, and increased sinkage) hinder a rover’s ability to drive, and should be considered when interpreting results from reduced-load mobility tests conducted on Earth.

Diagnosis of Challenges and Scrutinization of Opportunities in Regard to Harnessing of Hydropower Potential in Nepal

Nepal is a naturally blessed hydro-resources rich country with one of the highest per capita hydropower potentials in the world, yet hungry of economic enhancement through hydropower development. This paper emphasizes on challenges in this sector, mainly technical and investment (financial) challenges, among many, for not being fully able to harness this sector. Among the technical challenges, fragile geology, hydrologic variability, high rate of sedimentation, difficult terrain with dispersed settlement, stringent environmental concerns, lack of policy interventions in hydropower development etc have been the major obstacles to overcome. Similarly, regarding financial challenges, constraints in mobilizing funding from Financial Intermediaries (FIS), foreign exchange risk, repatriation risk, sovereign risk (country risk), payment risk, construction risks (time and cost overrun), hydrological risks, local level disputes and risks need to be conveniently addressed to.

ПОТЕНЦІАЛ ТА ПЕРСПЕКТИВИ РОЗМІЩЕННЯ ЗАКЛАДІВ ДОШКІЛЬНОЇ ОСВІТИ НА ТЕРИТОРІЯХ ЗІ СКЛАДНИМ РЕЛЬЄФОМ У КОНТЕКСТІ ПІВДЕННОЇ УКРАЇНИ

ПОТЕНЦІАЛ ТА ПЕРСПЕКТИВИ РОЗМІЩЕННЯ ЗАКЛАДІВ ДОШКІЛЬНОЇ ОСВІТИ НА ТЕРИТОРІЯХ ЗІ СКЛАДНИМ РЕЛЬЄФОМ У КОНТЕКСТІ ПІВДЕННОЇ УКРАЇНИ

Emergency Care Provided by the Israeli Military Airborne Combat Evacuation Unit during Helicopter Winch Rescue Operations

Objectives The objective of this study was to evaluate the emergency care provided by the Israeli Military Airborne Combat Evacuation Unit (MACEU) during helicopter winching operations. Methods: A retrospective cohort study was performed of all patients rescued by winching by the MACEU between December 2011 and October 2018. Data were extracted from the electronic medical records of the unit registry. The data collected included helicopter type, scene times, demographics, mechanism of injury, interventions, medications, and survival. Results: During the study period, 208 civilians with a mean age of 36.8 ± 19.2 years were evacuated from inaccessible areas, 192 were from difficult terrain, 10 from sea vessels, and 5 from floods. All patients were winched up with a crewmember. No patient or crewmember was injured during winching. Overall, 156/208 (75%) had a traumatic injury, and 52/208 (25%) had a medical emergency. Sikorsky UH-60 “BlackHawk” helicopters and Sikorsky CH-53 “Sea Stallion” helicopters were used in 179 and 28 operations, respectively. Eighteen different procedures were performed by the medical personnel of the unit on scene and en route. The most performed procedures were peripheral vascular access establishment (60.6%), fluids administration (57.7%), oxygen supplementation (42.8%), analgesia (39.9%) and spine immobilization (37.5%). On scene, none of the patients was treated with a physician-only intervention. Thirty/208 (14.5%) patients were winched-up in darkness conditions. Eleven/208 (5.3%) apneic breathing patients were winched up ventilated by a crewmember. All the six patients who had oxygen saturation ≥89% after entrance into the cabin, survived. Conclusions: The reported MACEU experience provides useful information on the clinical characteristics, medical interventions, and outcomes of patients rescued using a winching operation. Study findings emphasize the importance of airway management and ventilation during winching.

Construction Cost Analysis of Retaining Walls

Retaining walls are relatively rigid walls used to support the ground laterally so that it can be held at different levels on both sides [1]. Retaining walls are considered all technical works, which allow the implementation of a sharp change in the level of the earth's surface, in such a way that the ground-construction system presents limited displacement or is marginally restrained. Support structures are mainly used in cases of disruption of soil continuity resulting from an excavation, below the natural surface of the ground, such as when building roads in a difficult geographical terrain with steep slopes. It is also common for them to be used in the construction of basements in urban areas, when there are other buildings or roads around the perimeter. In special cases, functional reasons impose the local elevation of the ground surface with grounding in the area around the construction, such as on bridge piers or in port projects, so it becomes necessary to support the soil mass. Finally, the construction of retaining walls becomes necessary to stabilize and protect natural slopes that present kinematic instability. The purpose of the present work is to compare the cost of constructing three retaining walls (gravity, cantilever, braced) subject to identical ground pressures. The retaining walls were designed using the same finite element software (GEO5), taking into account common parameters for the soil stress, the strength properties of the soil mass, the wall material as well as the diameter of the reinforcing steel bars, so that the results can be absolutely comparable. The market research that followed produced interesting conclusions on the comparison of the cost estimates for the three retaining walls.

Drones as an Integral Part of Remote Sensing Technologies to Help Missing People

Due to the versatility of the drone, it can be applied in various areas and for different uses and as a practical support for human activities. In particular, this paper focuses on the situation in Italy and how the authorities use drones for the search and rescue of missing persons, especially now that a 10-year plague that has afflicted Italy with a large number of such incidents annually. Knowledge of the current legislation, the implementation of the drone with other instruments, specific pilot training, and experiential contributions are all essential elements that can provide exceptional assistance in search and rescue operations. However, to guarantee maximum effectiveness of the rescue device, they should seriously consider including teams with proven expertise in operating drones and count on their valuable contribution. Besides drones’ capacity to search large areas, thereby reducing the use of human resources and possibly limiting intervention times, to operate in difficult terrain and/or dangerous conditions for rescue teams, remote sensing tools (such as GPR or ground penetrating radar) as well as other disciplines (such as forensic archeology and, more generally, forensic geosciences) can be implemented to carry out search and rescue missions in case of missing persons.

Fiber BraggSensors on Strain Analysis of Power Transmission Lines.

The reliability and safety of power transmission depends first and foremost on the state of the power grid, and mainly on the state of the high-voltage power line towers. The steel structures of existing power line supports (towers) have been in use for many years. Their in-service time, the variability in structural, thermal and environmental loads, the state of foundations (displacement and degradation), the corrosion of supporting structures and lack of technical documentation are essential factors that have an impact on the operating safety of the towers. The tower state assessment used to date, consisting of finding the deviation in the supporting structure apex, is insufficient because it omits the other necessary condition, the stress criterion, which is not to exceed allowable stress values. Moreover, in difficult terrain conditions the measurement of the tower deviation is very troublesome, and for this reason it is often not performed. This paper presents a stress-and-strain analysis of the legs of 110 kV power line truss towers with a height of 32 m. They have been in use for over 70 years and are located in especially difficult geotechnical conditions—one of them is in a gravel mine on an island surrounded by water and the other stands on a steep, wet slope. Purpose-designed fiber Bragg grating (FBG) sensors were proposed for strain measurements. Real values of stresses arising in the tower legs were observed and determined over a period of one year. Validation was also carried out based on geodetic measurements of the tower apex deviation, and a residual magnetic field (RMF) analysis was performed to assess the occurrence of cracks and stress concentration zones.

Forwarder Productivity in Salvage Logging Operations in Difficult Terrain

Large scale windthrow salvage logging is increasing in Central Europe because of the growth of severe atmospheric events due to global heating. Sustainable forest operations in these conditions are challenging in terms of both productivity performances and safety of the operations. Fully mechanized harvesting systems are the preferred solution on trafficable terrains and proper slopes. However, different work methods and logistic organization of the operations could largely change the overall performances. The study observed three harvesting sites based on fully mechanized cut-to-length systems and located in areas affected by the Vaia storm, which hit north-eastern Italy in October 2018. The objectives were to estimate forwarder productivity in salvage logging in difficult terrain and to identify significant variables affecting this productivity under real working conditions. Time and motion studies were carried out and covered 59.9 PMH15, for a total of 101 working cycles, extracting a total volume of 1277 m3 of timber. Average time consumption for each site was 38.7, 42.2, and 25.1 PMH15 with average productivity of 22.5, 18.5, and 29.4 m3/PMH15, respectively, for Sites A, B, and C. A total of seven explanatory variables significantly affected forwarder productivity. Average load volume, maximum machine inclination during loading, and number of logs positively affected the productivity. On the contrary, travel distance, load volume, maximum ground slope during moving and loading have a negative influence. With an average travel distance of 500 m, the productivity resulted 20.52, 16.31, and 23.03 m3/PMH15, respectively, for Sites A, B, and C. An increase of 200 m of travel distance causes a decrease in productivity of 6%.

Kinematic analysis of the R subfamily of the HeIse wheels

In this paper, the kinematic analysis of a series of variable geometry legged wheels is presented. These mechanisms can transform a circular wheel into a hybrid legged wheel in order to combine the efficiency and ability to traverse difficult terrain of each method of locomotion. The inverse and direct kinematic problems of position and velocity are stated and solved. Then, a singularity analysis of the mechanisms is performed. The geometrical conditions that make the Jacobian matrices of the wheels singular are determined and interpreted. Subsequently, an exploration of the workspace is presented to show kinematic features of the wheels inside their operation region.

Autumn migration of birds over Polonyna Borzhava (Ukrainian Carpathians)

Migration processes of birds occurring on the Polonyna Borzhava ridge were studied. Material was collected during 52-days period since September till November 2018 and total duration of observations was equal to 307 hours. It was found that despite difficult terrain and variable weather conditions at least 48 species of birds migrate over Polonyna Borzhava. Among them the following species dominate: Chaffinch Fringilla coelebs, Common Crane Grus grus, Eurasian Siskin Spinus spinus, Common Wood Pigeon Columba palumbus, Great Tit Parus major, Goldfinch Carduelis carduelis, Water Pipit Anthus spinoletta, Blue Tit Cyanistes caeruleus, and also raptors: Sparrowhawk Accipiter nisus, Common Buzzard Buteo buteo, Goshawk Accipiter gentilis, Hen Harrier Circus cyaneus, Marsh Harrier Circus aeruginosus and other species. Among detected species six are under protection of the Red Data Book of Ukraine: Common Crane, Hen Harrier, Stock Dove Columba oenas, Alpine Accentor  Prunella collaris, Osprey Pandion haliaetus, and Peregrine Falcon Falco peregrinus. Median date of the overall bird passage falls on 9 October. Passage dynamics differs among species. Most of species prefer flight heights not higher than 55 m above the ridge, but some numerous species choose higher altitudes, for instance Wood Pigeon (85.6±62.7 m), and Common Crane (227.5±62.5 m).

STRUCTURE OF TEMPLE COMPLEXES UNDER CONDITIONS OF COMPLEX RELIEF AND DESIGN PRINCIPLES

The main direction of the research includes the analysis of the structure of temple complexes in difficult terrain. The influence of landscape morphology on the specifics of the structure and architecture of religious buildings is considered. One of the important components is the historical outline of the construction of temple complexes as unique events, as well as time as one of the main “building materials”. Based on the analysis, the design principles were developed: uniqueness, regional affiliation, continuity, contextuality, spatial narrative, structurality, geomorphological certainty, genios loci (Greek. genius of place), integrity, sacredness, nested structures, koinos bios (Greek. common life).

Intelligent Control of a Spinal Prosthesis to Restore Walking After Neural Injury: Recent Work and Future Possibilities

This review focuses on the development of intelligent, intuitive control strategies for restoring walking using an innovative spinal neural prosthesis called intraspinal microstimulation (ISMS). These control strategies are inspired by the control of walking by the nervous system and are aimed at mimicking the natural functionality of locomotor-related sensorimotor systems. The work to date demonstrates how biologically inspired control strategies, some including machine learning methods, can be used to augment remaining function in models of complete and partial paralysis developed in anesthetized cats. This review highlights the advantages of learning predictions to produce automatically adaptive control of over-ground walking. This review also speculates on the possible future applications of similar machine learning algorithms for challenging walking tasks including navigating obstacles and traversing difficult terrain. Finally, this review explores the potential for plasticity and motor recovery with long-term use of such intelligent control systems and neural interfaces.