Journal articles on the topic 'Edge-ground axe'
To see the other types of publications on this topic, follow the link: Edge-ground axe.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Edge-ground axe.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Hiscock, Peter, Sue O’Connor, Jane Balme, and Tim Maloney. "World’s earliest ground-edge axe production coincides with human colonisation of Australia." Australian Archaeology 82, no. 1 (January 2, 2016): 2–11. http://dx.doi.org/10.1080/03122417.2016.1164379.
Full text
2
Geneste, Jean-Michel, Bruno David, Hugues Plisson, Jean-Jacques Delannoy, and Fiona Petchey. "The Origins of Ground-edge Axes: New Findings from Nawarla Gabarnmang, Arnhem Land (Australia) and Global Implications for the Evolution of Fully Modern Humans." Cambridge Archaeological Journal 22, no. 1 (February 2012): 1–17. http://dx.doi.org/10.1017/s0959774312000017.
Full textAbstract:
The grinding of stone to make sharp cutting edges did not evolve with the emergence of biologically modern humans in Africa, but late in the Pleistocene at the completion or nearcompletion of the Out-of-Africa 2 migration. Here we discuss the earliest securely-dated fragment of ground-edge axe from Australia, dated at 35,500 cal. bp, an age slightly older or comparable to the earliest ages for edge-grinding from the Pacific Ocean's western seaboard. In this region ground-edge axes did not evolve with the emergence of agriculture, nor for the clearance of forests, but, rather, as socially mediated technology, part of the development of symbolic storage that is the hallmark of the evolution of cognitively modern humans at the geographical end, during, or following, Out-of-Africa 2.
3
Maloney, Tim Ryan, Sue O’Connor, India Ella Dilkes-Hall, and Michelle C. Langley. "Late Holocene edge-ground axe production and marine shell beads from Brooking Gorge 1 rockshelter, southern Kimberley." Australian Archaeology 84, no. 2 (May 4, 2018): 196–202. http://dx.doi.org/10.1080/03122417.2018.1522484.
Full text
4
Durakov, I. A., and V. I. Molodin. "Casting Mold for Producing Socketed Bronze Axe of the Late Krotovo (Cherno-Ozerye) Culture." Problems of Archaeology, Ethnography, Anthropology of Siberia and Neighboring Territories 27 (2021): 408–13. http://dx.doi.org/10.17746/2658-6193.2021.27.0408-0413.
Full textAbstract:
This article presents a ceramic casting mold for producing socketed bronze axe, found in the burial of the Late Krotovo (Cherno-Ozerye) caster at the Sopka-2/5 burial ground located in the Baraba forest-steppe. The mold included the fragments of two halves, aligned along the dividing line. A part of working chamber with cavities for fastening the core has survived. The mold was made of a mixture of clay, fine calibrated sand, and organic matter. The axe had an L-shape, rhomboid crosssection of the working part, and round socket with straight upper edge. The working chamber shows traces of thermal impact from repeated use. It could have become destroyed during its use and was placed in the grave as a replacement for a whole object, as a necessary tool of a caster. This type of axe is considered to be imported for the Late Krotovo (Cherno-Ozerye) culture, manifesting the Andronovo (Fedorovo) influence. Thus, socketed axes which significantly changed the capacity of the syncretic culture, should be added to previously identified set of bronze objects introduced into autochthonous Krotovo environment by the carriers of the Andronovo (Fedorovo) culture, who migrated from the west. This set also includes daggers of the Srubno-Andronovo type and bracelets with spiral ends. In the meantime, a casting mold for producing axes from the Late Krotovo burial is indisputable proof that such axes were manufactured by the local casters. There was a large amount of metal implements accompanying the deceased caster, and the presence of weapons (dagger and celt axe) indicated his privileged position. Apparently, the Late Krotovo (Cherno-Ozerye) society had a large property differentiation, and casters might have had a special status.
5
Wallis, Lynley A., Iain Davidson, Heather Burke, Scott Mitchell, Bryce Barker, Elizabeth Hatte, Noelene Cole, and Kelsey M. Lowe. "Aboriginal stone huts along the Georgina River, southwest Queensland." Queensland Archaeological Research 20 (August 8, 2017): 1. http://dx.doi.org/10.25120/qar.20.2017.3584.
Full textAbstract:
This paper reports on the recording of previously unpublished Aboriginal stone hut structures in southwestern Queensland. Located along the Georgina River, these 15 structures are typical of the region, being generally circular in plan view, with an average diameter of 5m and a 1m-wide opening consistently positioned to afford protection from prevailing winds. Evidence suggests these structures were roofed with vegetation and, while they pre-date the contact period, appear also to have been used into at least the late 1800s. Artefacts associated with them include stone flakes, cores and edge-ground axe fragments, freshwater mussel shells, rifle cartridge cases, fragments of glass, and metal objects. A comparison of these stone hut structures is made with similar features from elsewhere in Australia, demonstrating that there was a widespread but consistent use of stone for construction. This short report contributes to an increasing awareness of, and literature about, built structures in traditional Aboriginal societies.
6
Harper, Sam, Ian Waina, Ambrose Chalarimeri, Sven Ouzman, Martin Porr, Pauline Heaney, Peter Veth, and Kim Akerman. "Metal burial: Understanding caching behaviour and contact material culture in Australia's NE Kimberley." Journal of Social Archaeology 21, no. 1 (February 2021): 28–52. http://dx.doi.org/10.1177/1469605321993277.
Full textAbstract:
This paper explores identity and the recursive impacts of cross-cultural colonial encounters on individuals, cultural materials, and cultural practices in 20th-century northern Australia. We focus on an assemblage of cached metal objects and associated cultural materials that embody both Aboriginal tradition and innovation. These cultural materials were wrapped in paperbark and placed within a ring of stones, a bundling practice also seen in human burials in this region. This ‘cache' is located in close proximity to rockshelters with rich, superimposed Aboriginal rock art compositions. However, the cache shelter has no visible art, despite available wall space. The site shows the utilisation of metal objects as new raw materials that use traditional techniques to manufacture a ground edge metal axe and to sharpen metal rods into spears. We contextualise these objects and their hypothesised owner(s) within narratives of invasion/contact and the ensuing pastoral history of this region. Assemblage theory affords us an appropriate theoretical lens through which to bring people, places, objects, and time into conversation.
7
Woodman, P. C. "Excavations at Mad Mans Window, Glenarm, Co. Antrim: Problems of Flint Exploitation in East Antrim." Proceedings of the Prehistoric Society 58, no. 1 (1992): 77–106. http://dx.doi.org/10.1017/s0079497x00004102.
Full textAbstract:
This study examines the archaeological significance of the material from a group of Neolithic chipping floors rescued during the rebuilding of the Antrim coast road, at Mad Mans Window, south of Glenarm, Co. Antrim. It shows that the lithic production strategies vary significantly between assemblages although it is presumed that they are all Neolithic in date and come from the same area of coast. It is apparent that flint axe production was of limited importance on these sites and that in spite of the abundance of flint available along the Antrim coast, relatively few polished flint axes were manufactured. Instead the numerous flint caches found in adjacent parts of the north-east of Ireland tend to produce scrapers and blades. Hoards containing arrowheads may be confined to the Bronze Age.Around 300 polished flint axes and roughouts are known from Ireland. These are frequently small and only partially polished. A limited number of highly polished axes with ground flat side facets have been designated sub-type A. The tendency to use porcellanite rather than flint for axe manufacture may be due to its ability to withstand robust shock.During the last 100 years, the role of flint as a key resource in the stone age of north-eastern Ireland has always been recognized but this has usually led to an uncritical assumption as to the paramount importance of flint. Work in recent years has shown that its significance in attracting and retaining Mesolithic settlement may have been over-emphasized.The role of the flint industries in the Irish Neolithic in this region has never been properly assessed, either in relation to older Mesolithic manufacturing traditions or in the broader context of supply to the Neolithic communities of this part of Ireland.In particular, good or even reasonable quality flint is usually only exposed in Cretaceous outcrops along a narrow strip on the edge of the basalt plateau and, therefore, has a very limited availability in parts of Co. Antrim as well as parts of Counties Down and Deny. As a contrast, erratic and beach flint is available in some quantity down the east coast of Ireland from Co. Down to Wexford. A second potential constraining factor is that unlike Britain, where flint was exploited for axe manufacture in the east and other rocks in the west, flint sources and porcellanite for axe manufacturing are both found adjacent to each other in the same corner of Co. Antrim. In particular, a number of more substantial chipping floors of Neolithic age are known, e.g. the opencast quarry sites at Ballygalley Head. The purpose of this study is to assess the role of flint production on the Antrim coast with particular reference to its significance in the Neolithic. This topic will be developed in the context of an analysis of the material found at Mad Mans Window near Glenarm.
8
Yahner, Richard H., and Anthony L. Wright. "Depredation on Artificial Ground Nests: Effects of Edge and Plot Age." Journal of Wildlife Management 49, no. 2 (April 1985): 508. http://dx.doi.org/10.2307/3801563.
Full text
9
Brooks, Joseph, Anka Davila, and Akul Satish. "Inter-Edge Grouping: Are many figure-ground principles actually perceptual grouping?" Journal of Vision 17, no. 10 (August 31, 2017): 163. http://dx.doi.org/10.1167/17.10.163.
Full text
10
Baker, Sue, Leon Barmuta, Simon Grove, and Alastair Richardson. "Are streamside buffers edge-affected habitat for ground-dwelling forest beetle assemblages?" Biodiversity and Conservation 18, no. 13 (May 30, 2009): 3467–82. http://dx.doi.org/10.1007/s10531-009-9655-x.
Full text
11
Mehraban, A. A., and Mohammad Hassan Djavareshkian. "Experimental study of low Reynolds number effects on aerodynamics of smooth and sinusoidal leading-edge wings in the vicinity of the ground." Journal of Mechanical Engineering and Sciences 15, no. 2 (June 18, 2021): 8205–18. http://dx.doi.org/10.15282/jmes.15.2.2021.19.0644.
Full textAbstract:
Present study experimentally investigates the effects of ground clearance and Reynolds number on aerodynamic coefficients of smooth and sinusoidal leading-edge wings. Wind tunnel tests are conducted over a wide range of angles of attack from zero to 36 degrees, low Reynolds numbers of 30,000, 45,000 and 60,000, and also ground clearances of 0.5, 1 and ∞. Results showed that reduction of ground clearance and increment of Reynolds number cause the lift coefficient and the lift to drag ratio of both wings to be enhanced. Furthermore, the effects of Reynolds number and ground clearance on the smooth leading-edge wing are more than the sinusoidal leading-edge one. In addition, the sinusoidal leading-edge wing shows an excellent performance in the poststall region due to producing a higher lift and also by delaying the stall angle compared to the smooth leading-edge wing.
12
Panetta, Karen, Chen Gao, Sos Agaian, and Shahan Nercessian. "Nonreference Medical Image Edge Map Measure." International Journal of Biomedical Imaging 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/931375.
Full textAbstract:
Edge detection is a key step in medical image processing. It is widely used to extract features, perform segmentation, and further assist in diagnosis. A poor quality edge map can result in false alarms and misses in cancer detection algorithms. Therefore, it is necessary to have a reliable edge measure to assist in selecting the optimal edge map. Existing reference based edge measures require a ground truth edge map to evaluate the similarity between the generated edge map and the ground truth. However, the ground truth images are not available for medical images. Therefore, a nonreference edge measure is ideal for medical image processing applications. In this paper, a nonreference reconstruction based edge map evaluation (NREM) is proposed. The theoretical basis is that a good edge map keeps the structure and details of the original image thus would yield a good reconstructed image. The NREM is based on comparing the similarity between the reconstructed image with the original image using this concept. The edge measure is used for selecting the optimal edge detection algorithm and optimal parameters for the algorithm. Experimental results show that the quantitative evaluations given by the edge measure have good correlations with human visual analysis.
13
Manolis, James C., David E. Andersen, and Francesca J. Cuthbert. "Edge Effect on Nesting Success of Ground Nesting Birds Near Regenerating Clearcuts in a Forest-Dominated Landscape." Auk 119, no. 4 (October 1, 2002): 955–70. http://dx.doi.org/10.1093/auk/119.4.955.
Full textAbstract:
Abstract Forest fragmentation has been implicated as a cause of population declines of several Neotropical migrant bird species. Fragmentation increases the amount of habitat edge, and reduced nesting success rates near forest edges are well documented in agricultural landscapes (“edge effects”). However, edge effects in predominantly forested landscapes, particularly those related to timber harvest, are poorly understood. This study examines nesting success of ground nesting birds in relation to clearcut edges in a forest-dominated landscape in north-central Minnesota. A total of 383 nests of seven species of ground nesting birds were found and monitored during 1992–1998. Ovenbird (Seiurus aurocapilus; n = 318) and Hermit Thrush (Catharus guttatus; n = 44) nests composed the majority of the sample. Predation accounted for 94% of all nest failures. Brown-headed Cowbird (Molothrus ater) parasitism was low (1.8% for all ground nests). Using proportional hazards regression, distance to nearest clearcut edge was the best predictor of nest failure. For all ground nests, nesting success was 0.18 at 0–100 m, 0.39 at 101–500 m, and 0.52 at 501–954 m from nearest clearcut edge. Source–sink modeling indicated that distances ≤100 m from clearcut edges were sink habitats for Ovenbirds (i.e. recruitment was lower than survival). These results provide strong evidence of a negative edge effect on ground nests, extending 100 m or more from clearcut edges in a forest-dominated area of north-central Minnesota.
14
Santos, André Maurício de Melo, and Bráulio Almeida Santos. "Are the vegetation structure and composition of the shrubby Caatinga free from edge influence?" Acta Botanica Brasilica 22, no. 4 (December 2008): 1077–84. http://dx.doi.org/10.1590/s0102-33062008000400018.
Full textAbstract:
Edge influence, or edge effect, drives many biological changes in fragmented landscapes. This has been extensively studied in many forest ecosystems, but it remains to be described for the Brazilian Caatinga. Based on the biotic and physical conditions of the shrubby Caatinga, our prediction a priori was that this type of vegetation is free from edge influence in terms of vegetation structure and composition. We sampled shrubs, cacti and trees in twenty 200 m² plots on old edges (>60 yrs old) and interior of a 690 ha fragment, partially isolated and surrounded by Opuntia ficus-indica cacti. Plant height, stem diameter at ground level, stem density, species richness and diversity were statistically equal between edge and interior habitats. Magnitude of edge influence varied from -0.027 to 0.027, indicating low ecological importance of edge creation for the measured variables. Additionally, floristic similarity between habitats was 90% and a principal component analysis showed that species composition varied in a similar manner at edges and interiors. These results indicate that the vegetation of the sampled fragment is not ecologically affected by the creation of edges and suggests that changes in physical conditions and resource availability after edge creation are not enough to eliminate established plants or to alter recruitment and survival of new individuals.
15
Pitarka, Arben, Kojiro Irikura, Tomotaka Iwata, and Haruko Sekiguchi. "Three-dimensional simulation of the near-fault ground motion for the 1995 Hyogo-Ken Nanbu (Kobe), Japan, earthquake." Bulletin of the Seismological Society of America 88, no. 2 (April 1, 1998): 428–40. http://dx.doi.org/10.1785/bssa0880020428.
Full textAbstract:
Abstract The 17 January 1995 Hyogo-ken Nanbu earthquake is a typical example showing that the ground motions along basin-edge faults can be very destructive. In this study, we simulate the near-fault ground motion from this earthquake based on a kinematic fault model and a simplified 3D velocity structure of the Kobe area. The kinematic earthquake rupture and the wave propagation are modeled using a 3D finite-difference method (FDM). Our simulation identifies the basin-edge effect as an important factor that influenced the ground-motion amplification pattern in the Kobe area. We found that the coupling of the source directivity and basin-edge effects causes impulsive ground motions with extremely high amplitude at periods greater than 1 sec and in a narrow zone offset less than 1 km from the basin edge. The combination of these effects acted to create a fairly continuous band of amplification that extends about 30 km in an elongated zone parallel to the basin-edge boundary. In some areas, localized site effects might have been as important as the abovementioned effects, but they cannot explain the continuity of the extended east-west zone of damage.
16
Graves, Robert W., Arben Pitarka, and Paul G. Somerville. "Ground-motion amplification in the Santa Monica area: Effects of shallow basin-edge structure." Bulletin of the Seismological Society of America 88, no. 5 (October 1, 1998): 1224–42. http://dx.doi.org/10.1785/bssa0880051224.
Full textAbstract:
Abstract The 1994 Northridge earthquake produced ground motions in the northwest portion of the Los Angeles basin that were significantly larger than rock-site motions observed at locations just north of the basin. The Santa Monica area was hit particularly hard, with numerous structures being damaged or destroyed by the strong ground shaking. In this region, the basin-edge geology is controlled by the active strand of the east-west-striking Santa Monica fault, and virtually all of the structural damage occurred at or south of the fault location. We have used 2D finite-difference ground-motion simulations to investigate the effect of the basin-edge structure in amplifying ground response. Constraints on the basin-edge structure come from geologic cross sections, geophysical data, and seismological observations. Our simulations indicate that the shallow basin-edge structure (1 km deep) formed by the active strand of the Santa Monica fault creates a large amplification in motions immediately south of the fault scarp, in very good agreement with mainshock damage patterns, recorded ground motions, and locations of elevated site response. This large amplification results from constructive interference of direct waves with the basin-edge-generated surface waves and is quite similar to the basin-edge effect associated with the 1995 Kobe earthquake. In addition, we find that focusing effects created by the deeper basin structure (3 to 4 km deep) cannot explain the large motions observed immediately south of the fault scarp. This strongly suggests that the deep-basin focusing models proposed by Gao et al. (1996) and Alex and Olsen (1998) are not likely explanations of the observed pattern of ground-motion amplification in the Santa Monica area.
17
Xia, Liegang, Dezhi Yang, Junxia Zhang, Haiping Yang, and Jun Chen. "Enhanced Semantic Information Transfer of Multi-Domain Samples: An Adversarial Edge Detection Method Using Few High-Resolution Remote Sensing Images." Sensors 22, no. 15 (July 29, 2022): 5678. http://dx.doi.org/10.3390/s22155678.
Full textAbstract:
Edge detection of ground objects is a typical task in the field of remote sensing and has advantages in accomplishing many complex ground object extraction tasks. Although recent mainstream edge detection methods based on deep learning have significant effects, these methods have a very high dependence on the quantity and quality of samples. Moreover, using datasets from other domains in detection tasks often leads to degraded network performance due to variations in the ground objects in different regions. If this problem can be solved to allow datasets from other domains to be reused, the number of labeled samples required in the new task domain can be reduced, thereby shortening the task cycle and reducing task costs. In this paper, we propose a weakly supervised domain adaptation method to address the high dependence of edge extraction networks on samples. The domain adaptation is performed on the edge level and the semantic level, which prevents deviations in the semantic features that are caused by the overgeneralization of edge features. Additionally, the effectiveness of our proposed domain adaptation module is verified. Finally, we demonstrate the superior edge extraction performance of our method in the SEGOS edge extraction network in contrast to other edge extraction methods.
18
Mi, Jiaxin, Yongjun Yang, Huping Hou, Shaoliang Zhang, Zhongyi Ding, and Yifei Hua. "Impacts of Ground Fissures on Soil Properties in an Underground Mining Area on the Loess Plateau, China." Land 11, no. 2 (January 20, 2022): 162. http://dx.doi.org/10.3390/land11020162.
Full textAbstract:
Mining-induced ground fissures are the main type of geological disasters found on the Loess Plateau, China, and cause great impacts on the soil properties around ground fissures. However, little research has been conducted on the quantitative relationship between ground fissures and changes in soil properties. To address this, 40 ground fissures in the Yungang mining area, Datong City, Shanxi Province, China, were investigated, and changes in soil properties (soil organic matter, soil moisture, field capacity, bulk density, soil porosity, and grain compositions) were revealed by the difference in soil properties between the edge and contrast points around ground fissures. Redundancy analyses were used to illustrate the relationships between the value (Si_DV) and percentage (Si_DP) of the difference in soil properties between the edge and contrast points, as well as the ground fissures. The characteristics of ground fissures that had a significant correlation according to Pearson correlation analysis with Si_DP were selected and analyzed via multivariate linear fitting model, random forest model, and Back Propagation (BP) neural network model, respectively. Results show that soil organic matter, soil moisture content, bulk density, field capacity, and the content of clay at the edge points were significantly less than those at the contrast points; conversely, soil porosity at the edge points was significantly greater. The average percentage of the difference between the edge points and contrast points of ground fissures in these six properties was 15.27%, while soil moisture content showed the greatest change (20.65%). The Si_DP was significantly correlated with the width, slope, and vegetation coverage of ground fissures; however, the vegetation coverage was the determining factor. BP neural network model had the greatest performance in revealing the relationships between ground fissures and changes in soil properties. The model for soil organic matter had the highest accuracy (R2 = 0.89), and all others were above 0.5. This research provides insights into the quantitative relationship between ground fissures and their impacts on soil physical properties, which can be used in conjunction with remote sensing images to rapidly assess soil erosion risks caused by mining on a large scale, given that soil physical properties are closely related to topsoil stability.
19
Huang, Liang, Xueqin Yu, and Xiaoqing Zuo. "Edge Detection in UAV Remote Sensing Images Using the Method Integrating Zernike Moments with Clustering Algorithms." International Journal of Aerospace Engineering 2017 (2017): 1–7. http://dx.doi.org/10.1155/2017/1793212.
Full textAbstract:
Due to the unmanned aerial vehicle remote sensing images (UAVRSI) within rich texture details of ground objects and obvious phenomenon, the same objects with different spectra, it is difficult to effectively acquire the edge information using traditional edge detection operator. To solve this problem, an edge detection method of UAVRSI by combining Zernike moments with clustering algorithms is proposed in this study. To begin with, two typical clustering algorithms, namely, fuzzy c-means (FCM) and K-means algorithms, are used to cluster the original remote sensing images so as to form homogeneous regions in ground objects. Then, Zernike moments are applied to carry out edge detection on the remote sensing images clustered. Finally, visual comparison and sensitivity methods are adopted to evaluate the accuracy of the edge information detected. Afterwards, two groups of experimental data are selected to verify the proposed method. Results show that the proposed method effectively improves the accuracy of edge information extracted from remote sensing images.
20
Roume, Anthony, Marc Deconchat, Laurent Raison, Gérard Balent, and Annie Ouin. "Edge effects on ground beetles at the woodlot-field interface are short-range and asymmetrical." Agricultural and Forest Entomology 13, no. 4 (April 17, 2011): 395–403. http://dx.doi.org/10.1111/j.1461-9563.2011.00534.x.
Full text
21
Hara, Keisuke, Hiromi Isobe, and Akira Kyusojin. "Effects of Cutting Edge Truncation on Ultrasonically Assisted Grinding." Key Engineering Materials 389-390 (September 2008): 368–74. http://dx.doi.org/10.4028/www.scientific.net/kem.389-390.368.
Full textAbstract:
High precision mold grinding technique to obtain mirror surface is required which realizes minimization or omission of final polishing by skilled workers. In the previous reports, ultrasonically diamond grinding experiments were carried out to confirm ultrasonically oscillation effect for die steel face grinding. Mirror surface was obtained successfully and little abrasive worn out was found. In the above technique, the cutting edge shape of a tool affects the ground surface resulting from transcription of cutting edge. In other words, cutting edge truncation of grinding tool is required to be smooth and glossy surface. This paper describes the cutting edge truncation of diamond electroplated tools which are used in ultrasonically assisted grinding. Experiments were carried out to confirm truncation effects on the ground surface and grinding force. It was confirmed that cutting edge truncation is effective method to obtain mirror surface and excessive truncation causes large grinding force and chattering.
22
Zhang, Bin, Haocen Hong, Min Yu, and Huayong Yang. "Leakage analysis and ground tests of knife edge indium seal to lunar sample return devices." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 233, no. 6 (April 18, 2018): 2010–22. http://dx.doi.org/10.1177/0954410018768425.
Full textAbstract:
This work deals with the lunar sample return project, which requires lunar samples to be returned back to the ground without contamination. In this paper, a knife edge indium seal is proposed as a primary sealing form, where indium–silver alloy is welded into an annular groove of a cylindrical container firstly and then extruded by an annular knife edge of a cylindrical lid. The analysis of the leakage and sealing reliability of knife edge indium seal is the main aim of this paper. Firstly, the pretreatment of knife edge indium seal is discussed. Key techniques on indium welding are studied to evaluate its sealing reliability, with the tensile strength and welding void ratio mainly being discussed. Secondly, by means of “Roth” leakage theory, mathematical models on the leak rate for knife edge seal are established. By means of the finite element analysis, the knife edge geometry is optimized with minimum pressing force required. The results justify that the knife edge seal demands much lower pressing force to achieve a considerable sealing performance, which is suitable for low-powered operation. Finally, the ground tests are carried out to evaluate the feasibility of the indium welding and to measure the leak rate of the knife edge indium seal. Experimental results demonstrate the indium welding onto the stainless steel container is feasible, and the leak rate at room temperature is 3.0 × 10−10 Pa·m3/s, which is much lower than the rubber O-type ring seal. The knife edge indium seal is suitable for lunar sample return devices.
23
Hara, Keisuke, Hiromi Isobe, and Akira Kyusojin. "Optimization of Cutting Edge Truncation Depth for Ultrasonically Assisted Grinding to Finish Mirror Surface." Advanced Materials Research 76-78 (June 2009): 88–93. http://dx.doi.org/10.4028/www.scientific.net/amr.76-78.88.
Full textAbstract:
High precision mold grinding technique to obtain mirror surface is required which realizes minimization or omission of final polishing by skilled workers. In the previous reports, ultrasonic diamond grinding experiments were carried out to confirm ultrasonic oscillation effect for die steel face grinding. Smooth and glossy surfaces were obtained successfully and little abrasive worn out was found. In the above techniques require cutting edge truncation because the cutting edge shape of a tool affects the ground surface resulting from transcription of cutting edge. This paper describes optimization techniques for the cutting edge truncation of diamond electroplated tools which are used in ultrasonically assisted grinding. Experiments were carried out to confirm truncation effects on the ground surface and grinding force. It was confirmed that roughness was proportional to inverse of thrust force. Minimum roughness in grinding conditions were estimated from the proportional diagrams. The minimum roughness shows limit of roughness on an each grinding condition.
24
Zhang, Wen, Baosheng Wang, and Yong Wang. "Elastic Analysis of Nonhomogeneous Frozen Wall under Nonaxisymmetric Ground Stress Field and in State of Unloading." Advances in Materials Science and Engineering 2018 (July 3, 2018): 1–13. http://dx.doi.org/10.1155/2018/2391431.
Full textAbstract:
The mechanical analysis of frozen walls is a cornerstone technology of artificially frozen ground. The mechanical response of frozen walls is affected by heterogeneity, excavation unloading, uneven ground pressure, and the characteristics of surrounding rock. However, these factors are rarely taken into full consideration in existing analysis models. To address this shortfall, this study presents a plane-strain model that considers the inhomogeneity of frozen walls, the unloaded state of the frozen-wall inner edge, and the nonuniform ground stress field (abbreviated as “IF model”). The solution of the IF model is based on the superposition of thin concentric cylinders under two types of contact conditions: complete contact and smooth contact, and its validity is tested by a finite-element calculation. The calculation indicates that the excavation reduces the radial force and increases the tangential force between the frozen wall and the surrounding earth mass; the ground principal stress is rotated after the excavation. If the radial unloading equals the tangential unloading at the inner edge of the frozen wall, the response of the radial stress differs from that of the tangential stress at the outer edge of the frozen wall. The circumferential stress and the radial displacement at the inner edge correlate linearly with the nonuniform coefficient of the ground press and the unloading ratio. If the nonuniform coefficient is relatively small, the inner edge of the frozen wall may incur tensile damage. Compared with the model of a homogeneous frozen wall (abbreviated as “HF model”), which has a uniform temperature distribution, the absolute value of the circumferential stress is lower (higher) for the IF model where the temperature is above (below) average. When the frozen wall is relatively thick, the circumferential stress of the inner edge of the frozen wall is lower for the IF model than for the HF model. The percent reduction is 8.12%∼9.32% for rock freezing and 13.41%∼18.03% for soil freezing. The IF model proposed herein thus reflects the characteristics of frozen walls and surrounding rock more clearly and accurately than the HF model and obtains stress states closer to the reality. Therefore, the IF model is recommended for the design and construction of frozen walls.
25
Magura, Tibor, and Gábor L. Lövei. "The type of forest edge governs the spatial distribution of different-sized ground beetles." Acta Zoologica Academiae Scientiarum Hungaricae 66, Suppl. (December 28, 2020): 69–96. http://dx.doi.org/10.17109/azh.66.suppl.69.2020.
Full textAbstract:
Worldwide human-induced habitat fragmentation intensifies the emergence of forest edges. In addition to these edges, there are edges evolved by natural processes. Edge-maintaining processes (natural vs. anthropogenic) fundamentally determine edge responses, and thus edge functions. Species with various traits show fundamentally different edge response, therefore the trait-based approach is essential in edge studies. We evaluated the edge effect on the body size of ground beetles in forest edges with various maintaining processes. Our results, based on 30 published papers and 221 species, showed that natural forest edges were impenetrable for small species, preventing their dispersal into the forest interiors, while both the medium and the large species penetrated across these edges and dispersed into the forest interiors. Anthropogenic edges maintained by continued human disturbance (agriculture, forestry, urbanisation) were permeable for ground beetles of all size, allowing them to invade the forest interiors. Overwintering type (overwintering as adults or as larvae) was associated with body size, since almost two-thirds of the small species, while slightly more than a third of both the medium and the large species were adult overwintering. Based on this, size-dependent permeability of natural edges may be related to overwintering type, which basically determines species tolerance to human disturbance.
26
Tao, Huilin, Haikuan Feng, Liangji Xu, Mengke Miao, Huiling Long, Jibo Yue, Zhenhai Li, Guijun Yang, Xiaodong Yang, and Lingling Fan. "Estimation of Crop Growth Parameters Using UAV-Based Hyperspectral Remote Sensing Data." Sensors 20, no. 5 (February 27, 2020): 1296. http://dx.doi.org/10.3390/s20051296.
Full textAbstract:
Above-ground biomass (AGB) and the leaf area index (LAI) are important indicators for the assessment of crop growth, and are therefore important for agricultural management. Although improvements have been made in the monitoring of crop growth parameters using ground- and satellite-based sensors, the application of these technologies is limited by imaging difficulties, complex data processing, and low spatial resolution. Therefore, this study evaluated the use of hyperspectral indices, red-edge parameters, and their combination to estimate and map the distributions of AGB and LAI for various growth stages of winter wheat. A hyperspectral sensor mounted on an unmanned aerial vehicle was used to obtain vegetation indices and red-edge parameters, and stepwise regression (SWR) and partial least squares regression (PLSR) methods were used to accurately estimate the AGB and LAI based on these vegetation indices, red-edge parameters, and their combination. The results show that: (i) most of the studied vegetation indices and red-edge parameters are significantly highly correlated with AGB and LAI; (ii) overall, the correlations between vegetation indices and AGB and LAI, respectively, are stronger than those between red-edge parameters and AGB and LAI, respectively; (iii) Compared with the estimations using only vegetation indices or red-edge parameters, the estimation of AGB and LAI using a combination of vegetation indices and red-edge parameters is more accurate; and (iv) The estimations of AGB and LAI obtained using the PLSR method are superior to those obtained using the SWR method. Therefore, combining vegetation indices with red-edge parameters and using the PLSR method can improve the estimation of AGB and LAI.
27
Motoi, Naoki, Kenta Sasahara, and Atsuo Kawamura. "Switching Control Method for Stable Landing by Legged Robot Based on Zero Moment Point." Journal of Robotics and Mechatronics 25, no. 5 (October 20, 2013): 831–39. http://dx.doi.org/10.20965/jrm.2013.p0831.
Full textAbstract:
This paper proposes a switching control method to achieve a smooth transition from an edge landing to a sole landing for a legged robot. When a biped robot walks, an undesirable condition at the moment of landing, such as hunting between the ground and the foot, may occur for several reasons. To avoid this condition, this paper focuses on a method that uses simple controllers to ensure a smooth transition from an edge landing to a sole landing. In the event of an edge landing, a force controller should be implemented for a smooth transition to a sole landing. This is because the force controller enables the foot to contact the ground softly. After the landing state is shifted to the sole landing, the control method should be changed to the position controller. Therefore, it is necessary to switch the control method according to the contact condition between the foot and the ground. To avoid the chattering of the controller switching, several hysteresis values are used for the zeromoment point (ZMP) position and ZMP velocity in the switching function. Simulations and experimental results confirmed the validity of the proposed method.
28
Magura, Tibor, Gábor L. Lövei, and Béla Tóthmérész. "Edge responses are different in edges under natural versus anthropogenic influence: a meta-analysis using ground beetles." Ecology and Evolution 7, no. 3 (January 18, 2017): 1009–17. http://dx.doi.org/10.1002/ece3.2722.
Full text
29
Sakamoto, Haruhisa, Kyoko Nakamura, Yoshinori Sasaki, and Shinji Shimizu. "Analysis of Effective Cutting-Edge Distribution of Grinding Wheel Based on Topography of Working and Ground Surfaces." Advanced Materials Research 325 (August 2011): 60–65. http://dx.doi.org/10.4028/www.scientific.net/amr.325.60.
Full textAbstract:
In this study, the determination method of the number of the effective cutting-edges had been proposed based on the measurements of working surface topography and the grinding force. Furthermore, its validity is made clear based on the topographical analysis of the ground surface roughness of pure copper, which is excellent in transcribing the working surface. From the results, the following are found out: The ground surface topography contains the periodical component, which is originated in the grinding and dressing conditions, on the fractal noise component. The cutting traces by each cutting-edge can be countable from the ground surface profile, and then, the number of the effective cutting-edges is identified at one line within the working surface. On the other hand, the number of the effective cutting-edges also can be identified based on the working surface, but, this method requires the determination of the typical grain shape. From the experiment, it is confirmed that the grain shape should be almost spherical for making the numbers of the effective cutting-edge identified from the working and ground surfaces equal.
30
Lyalko, Vadim, Stanislav Dugin, Oksana Sybirtseva, Yelizaveta Dorofey, Stanislav Golubov, and Galyna Zholobak. "Gas exchange for the plants on the example of coastal sedge and comparison with the materials of spectro-gasometric ground-based measurements from the UAV and the Sentinel-2 satellite." Ukrainian journal of remote sensing 9, no. 4 (December 8, 2022): 26–34. http://dx.doi.org/10.36023/ujrs.2022.9.4.221.
Full textAbstract:
Spectro-gasometric ground-based measurements were carried out during 2020-2021. It was determined that five vegetation indices - REP (Red Edge Position), Green NRDI (Normalized Difference Vegetation Index), Green MOD (Green Model) and Red MOD (Red edge Model) are more responsive to the presence of СО2 concentration depending on leaf photosynthesis and leaf respiration of the coastal sedge (Carex riparia) with high correlation under Pearson from 0.60 to 0.72. Certain vegetation indices capture changes in СО2 concentration and can be recommended for use in carbon flux models for vegetation canopy. Data from DJI P4 Multispectral UAV, Parrot Bebop Pro Thermal and Sentinel-2 satellite compared to ground measurements on May 25, 2021.
31
WEN, XIAO-GANG. "TOPOLOGICAL ORDERS AND CHERN-SIMONS THEORY IN STRONGLY CORRELATED QUANTUM LIQUID." International Journal of Modern Physics B 05, no. 10 (June 1991): 1641–48. http://dx.doi.org/10.1142/s0217979291001541.
Full textAbstract:
We review the topological orders in strongly correlated quantum liquids. The characterization of the topological orders through ground state degeneracy, non-Abelian Berry's phases and edge excitations are discussed.
32
Li, Linpei, Xiangming Wen, Zhaoming Lu, and Wenpeng Jing. "An Energy Efficient Design of Computation Offloading Enabled by UAV." Sensors 20, no. 12 (June 13, 2020): 3363. http://dx.doi.org/10.3390/s20123363.
Full textAbstract:
The data volume is exploding due to various newly-developing applications that call for stringent communication requirements towards 5th generation wireless systems. Fortunately, mobile edge computing makes it possible to relieve the heavy computation pressure of ground users and decrease the latency and energy consumption. What is more, the unmanned aerial vehicle has the advantages of agility and easy deployment, which gives the unmanned aerial vehicle enabled mobile edge computing system opportunities to fly towards areas with communication demand, such as hotspot areas. However, the limited endurance time of unmanned aerial vehicle affects the performance of mobile edge computing services, which results in the incomplete mobile edge computing services under the time limit. Consequently, this paper concerns the energy-efficient scheme design of the unmanned aerial vehicle while providing high-quality offloading services for ground users, particularly in the regions where the ground communication infrastructures are overloaded or damaged after natural disasters. Firstly, the model of energy-efficient design of the unmanned aerial vehicle is set up taking the constraints of the energy limitation of the unmanned aerial vehicle, the data causality, and the speed of the unmanned aerial vehicle into account. Subsequently, aiming at maximizing the energy efficiency of the unmanned aerial vehicle in the unmanned aerial vehicle enabled mobile edge computing system, the bits allocation in each time slot and the trajectory of the unmanned aerial vehicle are jointly optimized. Secondly, a successive convex approximation based alternating algorithm is brought forward to deal with the non-convex energy efficiency maximization problem. Finally, it is proved that the proposed energy efficient scheme design of the unmanned aerial vehicle is superior to other benchmark schemes by the simulation results. Besides, how the performance of proposed scheme design change under different parameters is discussed.
33
Al-Jubair, Haider S., and Jawdat K. Abbas. "Bearing Capacity of Eccentrically Loaded Strip Footing Near The Edge of Cohesive Slope." Tikrit Journal of Engineering Sciences 14, no. 2 (June 30, 2007): 32–48. http://dx.doi.org/10.25130/tjes.14.2.02.
Full textAbstract:
The finite element method is used to investigate the behavior of a strip footing constructed near the edge of a sloping cohesive ground. The effects of variation in footing closeness, loading eccentricity and slope angle are studied also. It is proved that Bowles method overestimates the load carrying capacity of the concentrically loaded strip footings on cohesive soils. Decreasing the distance between the footing and the slope edge, increasing the eccentricity and slope angle reduce the ultimate bearing capacity. Slope effect diminishes as the footing distance from the edge approaches (1.5) times its width.
34
Ni, H., X. G. Lin, and J. X. Zhang. "APPLICATIONS OF 3D-EDGE DETECTION FOR ALS POINT CLOUD." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W7 (September 12, 2017): 277–83. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w7-277-2017.
Full textAbstract:
Edge detection has been one of the major issues in the field of remote sensing and photogrammetry. With the fast development of sensor technology of laser scanning system, dense point clouds have become increasingly common. Precious 3D-edges are able to be detected from these point clouds and a great deal of edge or feature line extraction methods have been proposed. Among these methods, an easy-to-use 3D-edge detection method, AGPN (Analyzing Geometric Properties of Neighborhoods), has been proposed. The AGPN method detects edges based on the analysis of geometric properties of a query point’s neighbourhood. The AGPN method detects two kinds of 3D-edges, including boundary elements and fold edges, and it has many applications. This paper presents three applications of AGPN, i.e., 3D line segment extraction, ground points filtering, and ground breakline extraction. Experiments show that the utilization of AGPN method gives a straightforward solution to these applications.
35
Nikolayev, V. A., and D. I. Troshin. "Continuous action right knife unit with ground interaction analysis." Russian Automobile and Highway Industry Journal 17, no. 4 (August 28, 2020): 452–63. http://dx.doi.org/10.26518/2071-7296-2020-17-4-452-463.
Full textAbstract:
Introduction. To solve the problem of accelerating the construction of roads, improving their quality, it is advisable to use a continuous action unit to form a underlying layer. The main working bodies of this unit are buckets, which cut off the soil layer from below and on the side. At the same time, the bottom knife cuts off the ground layer from below, the right knife on the side, and the console knife partially cuts the top layer of soil from below for the next bucket. In particular, the analysis of interaction with the soil of the right knife of the continuous action unit is of theoretical and practical interest. To do this, the right knife is divided into elements and analyzed the interaction of these elements with the ground. The consistent impact on the soil of many right knives, within the width of the grip of the unit, is replaced by the impact on the ground of one conventional right knife at a distance necessary for the development of one cubic meter of soil. The forces of interaction of the conventional right knife with the ground are called conditional forces.The method of research. The method for calculating the energy costs during punching the right knife into the ground is shown: on separating the formation of the ground from its body, on overcoming the ground friction on the edge of the blade, on overcoming the ground pressure on the edge of the blade, on accelerating the ground of the blade by means of the axle, on overcoming the ground friction on the shelf, to overcome the ground friction against the outside surface.The total energy costs of interacting with a soil of one cubic meter are derived from the addition of private energy costs. The method of calculating the horizontal longitudinal force needed to move the right knife is given.Results. On the basis of the methodology developed, energy costs are calculated when introducing the right knife into the ground: on separating the soil from its body, on overcoming the friction of the ground on the edge of the blade, on overcoming the pressure of the ground on the face of the blade, on the acceleration of the ground with a fascia blade, on overcoming the ground friction on the face. The total energy costs of the right knife interact with the soil of one cubic meter. The horizontal long-lived force needed to move the right knife has been determined.Conclusion. As a result of the calculations: the energy needed to cut the ground with the right knives, more than 71 J/cube. The horizontal longitudinal force needed to move the right knife is 730 N. To determine the total energy spent on cutting the ground by buckets of the unit to remove the top layer of soil from the underlying layer of the road, it is necessary to analyze the interaction with the soil of other elements of the bucket.
36
Shingu, Kiyoshi, and Kiyotoshi Hiratsuka. "Dynamic Response of Base Isolated Rotational Shell with Edge Beam and Fuzzy Vibration Control of the Shell." International Journal of Space Structures 12, no. 3-4 (September 1997): 173–79. http://dx.doi.org/10.1177/026635119701200306.
Full textAbstract:
Seismic isolation and fuzzy vibration control systems, which consist of a shell with an edge beam which has springs and variable dampers between the edge beam and the ground, are suggested by one of the authors. In this paper, natural vibration modes and natural frequencies of base isolated rotational shells with edge beams are shown. When the shell shakes due to vertical seismic forces, the seismic isolated system is implemented. As a result, stresses in the shell are significantly reduced. Furthermore, vibration control of the shell is carried out. Then the damping ratios are adjusted by the fuzzy theory, and stresses in the shell are further reduced.
37
Chandler, A. M. "Combined seismic base shear and torsional loading provisions in the 1990 edition of the National Building Code of Canada." Canadian Journal of Civil Engineering 18, no. 6 (December 1, 1991): 945–53. http://dx.doi.org/10.1139/l91-117.
Full textAbstract:
This paper evaluates the earthquake-resistant design provisions of the 1990 edition of the National Building Code of Canada (NBCC 1990) for asymmetric building structures subjected to combined lateral shear and torsional dynamic loadings arising from earthquake base excitation. A detailed parametric study is presented, evaluating the dynamic edge displacement response in the elastic range, for the side of the building which is adversely affected by lateral–torsional coupling. A series of buildings is studied, with realistic ranges of the fundamental natural period, structural eccentricity, and uncoupled frequency ratio. These buildings are evaluated under base loadings arising from a total of 45 strong motion records taken from earthquakes in North America, Mexico, Europe, the Middle East, and Southern Pacific, categorized according to site soil conditions and the ratio a/v of peak ground acceleration to velocity. The latter parameter together with the uncoupled lateral period are found to influence strongly the combined dynamic edge response, with the greatest forces on edge members arising from earthquakes with high a/v ratio in structures with natural periods below 0.8 s. In this case the NBCC 1990 loading provisions significantly underestimate the elastic dynamic response. For buildings with periods longer than 0.8 s, the conservatism of the base shear provisions leads to overestimation of combined dynamic edge response in asymmetric systems, and this is also true in the short-period range for buildings subjected to ground motions with low a/v ratio. The NBCC 1990 provisions are reasonably conservative for short-period systems subjected to ground motions with intermediate a/v ratio. Key words: earthquakes, seismic, design, response, spectra, base, shear, torsional, provisions.
38
Beke, Ákos, Sándor Szabó, and Bogdán Zavalnij. "Some Zero-One Linear Programming Reformulations for the Maximum Clique Problem." Mathematica Pannonica 27_NS1, no. 1 (April 8, 2021): 32–47. http://dx.doi.org/10.1556/314.2020.00005.
Full textAbstract:
Many combinatorial optimization problems can be expressed in terms of zero-one linear programs. For the maximum clique problem the so-called edge reformulation is applied most commonly. Two less frequently used LP equivalents are the independent set and edge covering set reformulations. The number of the constraints (as a function of the number of vertices of the ground graph) is asymptotically quadratic in the edge and the edge covering set LP reformulations and it is exponential in the independent set reformulation, respectively. F. D. Croce and R. Tadei proposed an approach in which the number of the constraints is equal to the number of the vertices. In this paper we are looking for possible tighter variants of these linear programs.
39
S. Mohan Reddy, S., M. Vinod Kumar, B. Sanjay, and K. Aruna Kumari. "Comparative Analysis of Edge Feeding and coaxial Feeding Technique with Fixed Frequency." International Journal of Engineering & Technology 7, no. 2.7 (March 18, 2018): 848. http://dx.doi.org/10.14419/ijet.v7i2.7.11080.
Full textAbstract:
The performance of rectangular microstrip patch antenna with the edge feeding and coaxial feeding techniques with DGS (Defective ground structure) and DSS (Defective substrate structure) are analyzed. It was observed that the return loss for Edge feeding is -28.39dB, for DSS it is - 26.44 and return loss for coaxial with DGS is -27.50dB and for DSS is -28.52. VSWR is approximately equal to 1 for all designs and also it was observed that the Gain is enhancement in Edge feeding and Bandwidth is improvement with coaxial feeding. The antenna designing and simulation is done by using the ANSOFT HFSS Software.
40
Birwal, Amit, Sanjeev Singh, Binod Kumar Kanaujia, and Sachin Kumar. "Broadband CPW-fed circularly polarized antenna for IoT-based navigation system." International Journal of Microwave and Wireless Technologies 11, no. 08 (May 31, 2019): 835–43. http://dx.doi.org/10.1017/s1759078719000461.
Full textAbstract:
AbstractThe paper presents a new coplanar waveguide (CPW)-fed rectangular patch antenna with a square-shaped ground plane that can be employed in modern advanced navigation systems. For realizing broad impedance bandwidth in the proposed antenna, a wide slot is introduced in the square ground plane and the rectangular patch is shifted toward the left edge of the ground surface. In addition, by means of introducing square-shaped stubs near the left and right edge of the ground plane, the circular polarization is achieved at L1, L2, and L5 satellite bands. As per the simulation results, the proposed antenna provides a wide impedance bandwidth (S11<−10 dB) of 123% (1.12–4.72 GHz) and 3 dB axial ratio bandwidth of 11% (1.15–1.29 GHz) and 18% (1.5–1.8 GHz) suitable for multipurpose wireless applications. The designed single feed circularly polarized antenna is low profile, small size, light weight and easily integrable with other high-frequency communication devices. To validate radiation performance of the proposed structure, the antenna is fabricated and integrated with the commercially available Global Positioning System (GPS) receiver and it is found that the measured values are in close agreement with the desired results.
41
Xiao, Xiang, Hong Li, Jun Tie, and Jing Lu. "Half Metallic Behavior in H-Terminated Zigzag BC2N Nanoribbons." Applied Mechanics and Materials 864 (April 2017): 30–35. http://dx.doi.org/10.4028/www.scientific.net/amm.864.30.
Full textAbstract:
We study structural, stability, electronic and magnetic properties of zigzag-edged BC2N nanoribbons (ZBC2NNRs) with H-termination in the view of first principles calculations. Four kinds of edge arrangements are considered, labeled as B-C, N-C, N-B, and C-C. Interestingly, we find these four types of H-terminated ZBC2NNRs have various electronic structures. The half-metal and semi-metal are obtained depending on the edge atom alignment. The B-C and N-C ZBC2NNRs with H-termination are half-metals with antiferromagnetic (AFM) ground states. The magnetic moments of the antiferromagnetic (AFM) state always prefer to locate at the ribbon edges. However, the N-B and C-C ZBC2NNRs show spin-unpolarized semi-metallic behaviors at ground states. Our results suggest that the H-terminated ZBC2NNRs can be a promising candidate material in nanoelectronics and nanospintronics.
42
Cheor, Wai Loon, Azremi Abdullah Al-Hadi, Ping Jack Soh, and Mohd Faizal Jamlos. "Study of multiple antennas with defected ground slot for low-band LTE application." Bulletin of Electrical Engineering and Informatics 8, no. 1 (March 1, 2019): 83–89. http://dx.doi.org/10.11591/eei.v8i1.1421.
Full textAbstract:
This study is focused on highly coupled multiple antennas with defected ground slot techniques. Two Printed Inverted-F Antenna (PIFA) are positioned at the top edge of chassis symmetrically. Both antennas are operating at low-band Long-Term Evolution (LTE) with center frequency, 829MHz. Rectangular defected ground slot is implemented to reduce the coupling effect between the antennas on the ground plane of the small chassis. Parameter study of the rectangular defected ground slot is studied with different width, W and length, L. Furthermore, the optimized dimensions of rectangular defected ground slot, W and L are simulated and presented. The optimized defected ground slot reduced the mutual coupling up to -4.5 dB. The envelope correlation coefficient (ECC) achieved less than 0.5. The ground plane of the multiple antenna structure has been further investigated by introducing another slot with a gap of 1mm between them. The achieved result is not significant in term of S-parameter and ECC compared to single defected ground slot.
43
Bouchard, Patrice, Terry A. Wheeler, and Henri Goulet. "DESIGN FOR A LOW-COST, COVERED, RAMP PITFALL TRAP." Canadian Entomologist 132, no. 3 (June 2000): 387–89. http://dx.doi.org/10.4039/ent132387-3.
Full textAbstract:
Pitfall traps are used extensively to sample ground-dwelling arthropods for systematic and ecological studies. They are inexpensive and easy to use and can be operated for relatively long periods of time without maintenance. These traps can collect arthropods in numbers that are suitable for rigorous statistical analysis, although their efficiency is influenced by many biotic and abiotic variables (Greenslade 1964; Spence and Niemelä 1994). Typically, pitfall traps are most productive when they are buried in the substrate, with the upper edge flush with the soil surface; traps with their upper edge above the substrate are much less effective (Greenslade 1964). Because of this, studies of ground-dwelling arthropods in habitats where soil is thin or lacking, or where digging is difficult, are left with no satisfactory alternatives to pitfall traps. A ramp pitfall trap developed by Bostanian et al. (1983) is useful in these habitats because it can be placed on the ground surface without digging. However, the original metal design was strongly biased toward the collection of large (>10 mm) ground beetles (Coleoptera: Carabidae) (Bostanian et al. 1983); it was also large, bulky, and relatively expensive. In this paper, we describe a ramp pitfall trap that is inexpensive, easily constructed, and durable. The trap is light, portable, easily installed, and effective in collecting all sizes of arthropods and can be used in many habitat types.
44
Yang, Li, Xiangguang Kong, Yaowen Qi, and Chengsheng Pan. "A Collaborative Cache Strategy in Satellite-Ground Integrated Network Based on Multiaccess Edge Computing." Wireless Communications and Mobile Computing 2021 (December 3, 2021): 1–14. http://dx.doi.org/10.1155/2021/8121509.
Full textAbstract:
Multiaccess edge computing (MEC) provides users with a network environment and computing storage capacity at the edge of the network, ensuring a deterministic service with low delivery delay. This paper introduces a new satellite-ground integrated collaborative caching network architecture based on MEC and studies the caching strategy. On the ground side, the edge nodes (ENs) are deployed to the user side to form a hierarchical collaborative cache mode centered on the base station. On the satellite side, we utilize intelligent satellite ENs to precache and multicast the highly popular contents, reducing the initial content delivery delay. Under the constraints of the user demand and storage capacity, we study the deployment and cache scheme of ENs and establish the delivery delay minimization problem. To solve the problem, we propose a content update decision parameter for content cache update and transform the problem into improving the hit rate of ENs. Simulation results show that the proposed MEC network architecture and content caching scheme can increase the caching system hit rate to 64% and reduce the average delay by 32.96% at most.
45
Kumar, Anubhav, Asok De, and Rakesh K. Jain. "Circularly polarized CPW fed MIMO/Diversity antenna for Wi-Fi and WLAN applications." Frequenz 76, no. 1-2 (October 22, 2021): 37–44. http://dx.doi.org/10.1515/freq-2021-0057.
Full textAbstract:
Abstract In this paper, circular polarized two-element and eight-element CPW fed MIMO/Diversity antenna with defected ground is presented. The dimension of the two-port antenna is 30 mm × 30 mm whereas the edge-to-edge gap between radiating elements is 5.65 mm. The |S11| in dB varies from 4.95 to 5.95 GHz with a gain up to 4.1 dB and efficiency is more than 90%. The isolation of two-element CPW antenna is more than 20 dB with open and diagonal stub in the ground whereas more than 18.7 dB for eight-element antenna without decoupling network. The circular and rectangular stub perturbs the surface current in the ground and is responsible for RHCP and LHCP in two-elements and eight-elements antenna where it covers the complete operating band. The acceptable ECC, TARC, DG, and CCL values of the antenna are determined which represents the diversity characteristics of the antenna. The Wi-Fi/WLAN applications can be fulfilled with the proposed two and eight-element antenna.
46
Wang, Xingzheng, Songwei Chen, Jiehao Liu, and Guoyao Wei. "High Edge-Quality Light-Field Salient Object Detection Using Convolutional Neural Network." Electronics 11, no. 7 (March 28, 2022): 1054. http://dx.doi.org/10.3390/electronics11071054.
Full textAbstract:
The detection result of current light-field salient object detection methods suffers from loss of edge details, which significantly limits the performance of subsequent computer vision tasks. To solve this problem, we propose a novel convolutional neural network to accurately detect salient objects, by digging effective edge information from light-field data. In particular, our method is divided into four steps. Firstly, the network extracts multi-level saliency features from light-field data. Secondly, edge features are extracted from low-level saliency features and optimized by ground-truth guidance. Then, to sufficiently leverage high-level saliency features and edge features, the network hierarchically fuses them in a complementary manner. Finally, spatial correlations between different levels of fused features are considered to detect salient objects. Our method can accurately locate salient objects with exquisite edge details, by extracting clear edge information and accurate saliency information and fully fusing them. We conduct extensive evaluations on three widely used benchmark datasets. The experimental results demonstrate the effectiveness of our method, and it is superior to eight state-of-the-art methods.
47
Kopačková-Strnadová, Veronika, Lucie Koucká, Jan Jelének, Zuzana Lhotáková, and Filip Oulehle. "Canopy Top, Height and Photosynthetic Pigment Estimation Using Parrot Sequoia Multispectral Imagery and the Unmanned Aerial Vehicle (UAV)." Remote Sensing 13, no. 4 (February 16, 2021): 705. http://dx.doi.org/10.3390/rs13040705.
Full textAbstract:
Remote sensing is one of the modern methods that have significantly developed over the last two decades and, nowadays, it provides a new means for forest monitoring. High spatial and temporal resolutions are demanded for the accurate and timely monitoring of forests. In this study, multi-spectral Unmanned Aerial Vehicle (UAV) images were used to estimate canopy parameters (definition of crown extent, top, and height, as well as photosynthetic pigment contents). The UAV images in Green, Red, Red-Edge, and Near infrared (NIR) bands were acquired by Parrot Sequoia camera over selected sites in two small catchments (Czech Republic) covered dominantly by Norway spruce monocultures. Individual tree extents, together with tree tops and heights, were derived from the Canopy Height Model (CHM). In addition, the following were tested: (i) to what extent can the linear relationship be established between selected vegetation indexes (Normalized Difference Vegetation Index (NDVI) and NDVIred edge) derived for individual trees and the corresponding ground truth (e.g., biochemically assessed needle photosynthetic pigment contents) and (ii) whether needle age selection as a ground truth and crown light conditions affect the validity of linear models. The results of the conducted statistical analysis show that the two vegetation indexes (NDVI and NDVIred edge) tested here have the potential to assess photosynthetic pigments in Norway spruce forests at a semi-quantitative level; however, the needle-age selection as a ground truth was revealed to be a very important factor. The only usable results were obtained for linear models when using the second year needle pigment contents as a ground truth. On the other hand, the illumination conditions of the crown proved to have very little effect on the model’s validity. No study was found to directly compare these results conducted on coniferous forest stands. This shows that there is a further need for studies dealing with a quantitative estimation of the biochemical variables of nature coniferous forests when employing spectral data that were acquired by the UAV platform at a very high spatial resolution.
48
Sritharan, S., and G. H. McVerry. "Microzone effects in the Hutt Valley in records from a strong-motion accelerograph array." Bulletin of the New Zealand Society for Earthquake Engineering 25, no. 4 (December 31, 1992): 246–64. http://dx.doi.org/10.5459/bnzsee.25.4.246-264.
Full textAbstract:
Ground motions recorded in several earthquakes by the Hutt Valley strong-motion accelerograph array are analyzed to demonstrate and quantify microzone effects. Spectral amplifications in low to moderate ground shaking are calculated at sites with different soil conditions with respect to a reference site located on rock adjacent to the edge of the valley. It is shown that the response characteristics of various sites correlate well with the soil conditions underlying the sites. A shallow site located on 20 m of sediment adjacent to the edge of the valley produces short-period amplification, with the average amplification curve for the 5% damped acceleration response, spectrum peaking at 0.35 s with a value of 4. Deeper sites with up to 300 m of stiff sediments yield broad-band amplifications up to 2 s period, with typical maximum amplifications of 5-10. The greatest amplifications, exceeding 10, are obtained at two sites which are located on shallow very soft deposits.
49
Jiang, T., and D. E. Ellis. "X-ray absorption near edge structures in cobalt oxides." Journal of Materials Research 11, no. 9 (September 1996): 2242–56. http://dx.doi.org/10.1557/jmr.1996.0285.
Full textAbstract:
Theoretical studies have been made of K-edge x-ray absorption near edge structure (XANES) of Co in CoO, Co(OH)2, CoTiO3, Co3O4, and CoAl2O4. Correlations of experimental near edge features with site symmetry, local geometry, local electronic structure, i.e., atomic configuration, charge transfer, and backscattering from neighboring atomic potentials are interpreted. The self-consistent Discrete Variational Xa Method (DV-Xα) within an embedded cluster technique has been used to generate the crystal potential. A multiple scattering (MS) approach is then used to solve for the final state wave function. The ground state DV wave functions are analyzed in terms of the projected density of states, whereas the final state MS continuum wave functions are analyzed through the concept of photoelectron trapping time.
50
Koenderink, Jan. "Macchie, Passages and ‘Edges Lost & Found’." Art and Perception 7, no. 2-3 (November 29, 2019): 83–107. http://dx.doi.org/10.1163/22134913-20191122.
Full textAbstract:
In the visual arts, one often composes a spatially organised array of elements. These elements are often roughly uniform patches (‘macchie’) and edges. These are mutually complementary and often imply each other. ‘Edges’ may either divide or unite macchie, whereas adjacent macchie may imply an edge. Edges may be common boundaries as in cloisonnism, or be one-sided as in outline. Composition often requires that edges be ‘lost’, either to avoid the dreaded silhouette effect, or to merge macchie that are semantically distinct, like figure and ground. This leads to planned ‘passages’ or various modulations of edge quality, the ‘lost & found’ quality being most common. I relate such conventional artistic devices to the concept of ‘edge’ in image processing and human vision.