site conditions
Recently Published Documents


TOTAL DOCUMENTS

821
(FIVE YEARS 201)

H-INDEX

37
(FIVE YEARS 5)

2022 ◽  
Vol 326 ◽  
pp. 107802
Author(s):  
Erin Daly ◽  
Keunbae Kim ◽  
Guillermo Hernandez-Ramirez ◽  
Thomas Flesch

2022 ◽  
Vol 14 (2) ◽  
pp. 847
Author(s):  
Danmei Wang ◽  
Jiping Li ◽  
Tao Tang

Close-to-nature management (CTNM) is the most promising option for plantation silviculture and has received widespread attention in recent years. Stand density is a key variable in CTNM, as it directly influences growth and yield. Research for the optimal density that maximizes the total harvest has been ongoing. In this paper, a dynamic programming model was applied to the CTNM of Phoebe bournei plantations for the first time to solve the problem of stand density and target tree density control. This paper took Phoebe bournei plantations in Jindong Forest Farm of Hunan Province as the research object. Based on the data of seven consecutive years from 2015 to 2021, Richard’s growth equation was used to fit the height growth equation and basal area growth equation of Phoebe bournei. Stand growth was divided into five development stages according to the forest growth process and characteristics. Stand density and basal area were selected as two-dimensional state variables, and the maximum total harvest in the entire stand growth process was used as the objective function to establish a dynamic programming model. The optimal stand density and target tree density at each growth stage of the stand under three different site conditions were determined. According to the results obtained, the objective forest shape was designed for the stand under three types of site conditions, which can provide a theoretical basis for the CTNM of Phoebe bournei plantations to make the stand achieve the maximum harvest.


2022 ◽  
Vol 964 (1) ◽  
pp. 012003
Author(s):  
Nguyen Thi Thanh Huong ◽  
Ho Dinh Bao ◽  
Cao Thi Hoai ◽  
Phan Thi Hang ◽  
Ngo The Son ◽  
...  

Abstract Remote sensing (RS) and Geographic information system (GIS) is widely applied in the world and gradually affirms its role in Vietnam in managing agricultural and forest resources. This application is highly effective, providing information timely for managers to make decisions and build development strategies. In this study, RS and GIS were integrated to assess suitability for key crop species in Dak Nong province including coffee, rubber, cashew, and durian based on their suitability to site conditions such as soil (soil type, soil texture, soil thickness), topography (elevation, slope) and climate (temperature, precipitation). Using the restrictive method and overlapping map layers of natural factors, classified into adaptive levels according to FAO (1976). Results show that most land areas in Dak Nong province have different levels of potential suitability for key crop species ranging from non-adaptive to lesst-adaptive and moderately adaptive. However, most suitable areas for key crops are only at low (accounting for a large proportion) and the average adaptation level. The findings from the study are the scientific information for managers to make decisions regarding the structure of major crops in the province.


2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Xinwei Lin ◽  
Shengzheng Wang ◽  
Zhen Sun ◽  
Min Zhang

Wearing safety rope while working at the loft and over the side of a ship is an effective means to protect seafarers from accidents. However, there are no active and effective monitoring methods on ships to control this issue. In this article, a one-stage system is proposed to automatically monitor whether the crew is wearing safety ropes. When the system detects that a crew enters the work area without a safety rope, it will warn the supervisor. In this regard, a safety rope wearing detection dataset is established. Then a data augmentation algorithm and a boundary loss function are designed to improve the training effect and the convergence speed. Furthermore, features from different scales are extracted to get the final detection results. The obtained results demonstrate that the proposed approach YOLO-SD is effective at different on-site conditions and can achieve high precision (97.4%), recall rate (91.4%), and mAP (91.5%) while ensuring real-time performance (38.31 FPS on average).


2021 ◽  
Vol 11 (2) ◽  
pp. 67-76
Author(s):  
Marina A. ZORINA ◽  
Galina N. RYAZANOVA ◽  
Evgenij V. ILDIYAROV

The principles of determining the conditions of tightness of the construction site in accordance with the requirements of normative documentation are shown. On concrete examples the features of defi nition of types of cranes, conditions of their placement on a construction site are considered. Shows examples of the placement of diff erent valves within a single construction site. The possibilities of limiting the boundaries of the zones of operation of the crane are determined. Possibilities of restriction of a dangerous zone of action of the crane according to the standard literature are presented.


Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1766
Author(s):  
Marta Damszel ◽  
Hanna Szmidla ◽  
Katarzyna Sikora ◽  
Agata Młodzińska ◽  
Sławomir Piętka ◽  
...  

The mycobiota of the fine roots of Pseudotsuga menziesii were studied as a measure of the adaptation of this alien species to new soil and climatic conditions. We hypothesized that after approximately 130 years of growth in a given habitat, the fungal community colonizing the fine roots of introduced trees would resemble the biota of Pinus sylvestris and Fagus sylvatica in surrounding stands of similar age and site conditions. The genetic material isolated from the fine roots was subjected to metagenomic analysis. We recorded 33, 97 and 95 OTUs exclusively from root samples of Douglas fir, beech and pine, respectively; 124 were common to all sample types. The biota from the roots of P. menziesii featured a less diverse taxonomic composition and were characterized by the highest proportion of symbiotrophs (71.8%) versus saprothrophs (5.6%) and pathogens (0.24%). Some fungal taxa (19) in the roots of P. menziesii were common with the biota in the roots of other adjacent trees, while some (7) were unique to Douglas fir. Our results indicate a locally differentiated strategy of naturalness of fungi inhabiting soil and roots of P. menziesii, although 130 years have passed since the introduction of the species.


2021 ◽  
Author(s):  
Chhotu Kumar Keshri ◽  
William Kumar Mohanty

Abstract India's Indo-Gangetic Plains (IGP) and its proximity to the Himalayas are seismically the most vulnerable zone. For seismic hazard analysis, it requires a reliable Ground Motion Prediction Equations (GMPEs) for this region. The strong motion accelerometer data are used for the present study from 2005 to 2015. PSA of 5% damped linear pseudo-absolute acceleration response spectra at 27 periods ranging from 0.01 s to 10 s used for regression. Two-stage nonlinear regression is used to train the functional form of a nonlinear magnitude scaling, distance scaling, and site conditions. The model includes a regionally independent geometric attenuation finite fault distance metric, style of faulting, shallow site response, basin response, hanging wall effect, hypocentre depth, regionally dependent anelastic attenuation, site conditions, and magnitude-dependent aleatory variability. We consider our new GMPE is valid for earthquakes from active tectonic shallow crustal continental earthquakes for estimating horizontal ground motion for rupture distances ranging from 1 km to 1500 km and magnitudes ranging from 3.3 to 7.9, and focal depth 1-70 km. The proposed GMPEs developed in this study for predicting PGA and PSA are compared with the Campbell and Bozorgnia 2008, 13 and 14, and North Indian GMPEs for IGP, which is agreed upon consistently. Calibration with observed data gives us the confidence to predict the ground motion from the seismic gaps of Himalaya ranges for the Indo-Gangetic plains. The predicted coefficients of the nonlinear model are anticipated to be valuable for probabilistic seismic hazard analysis over the IGP.


Buildings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 600
Author(s):  
Matthew S. K. Yeo ◽  
S. M. Bhagya P. Samarakoon ◽  
Qi Boon Ng ◽  
Yi Jin Ng ◽  
M. A. Viraj J. Muthugala ◽  
...  

False ceilings are often utilised in residential and commercial spaces as a way to contain and conceal necessary but unattractive building infrastructure, including mechanical, electrical, and plumbing services. Concealing such elements has made it difficult to perform periodic inspection safely for maintenance. To complement this, there have been increasing research interests in mobile robots in recent years that are capable of accessing hard-to-reach locations, thus allowing workers to perform inspections remotely. However, current initiatives are met with challenges arising from unstructured site conditions that hamper the robot’s productivity for false ceiling inspection. The paper adopts a top-down approach known as “Design for Robots”, taking into account four robot-inclusive design principles: activity, accessibility, safety, observability. Falcon, a class of inspection robots, was used as a benchmark to identify spatial constraints according to the four principles. Following this, a list of false ceiling design guidelines for each category are proposed.


Sign in / Sign up

Export Citation Format

Share Document