scholarly journals Active and Passive Haptic Perception of Shape: Passive Haptics Can Support Navigation

Electronics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 355 ◽  
Author(s):  
José-Luis Rodríguez ◽  
Ramiro Velázquez ◽  
Carolina Del-Valle-Soto ◽  
Sebastián Gutiérrez ◽  
Jorge Varona ◽  
...  
Keyword(s):  
Motor Activity ◽  
Haptic Perception ◽  
Shape Recognition ◽  
Haptic Interactions ◽  
Passive Haptics ◽  
First Case ◽  
Challenging Tasks ◽  
Series Of Experiments ◽  
Perceptual Characteristics ◽  
Haptic Environments

Real-time haptic interactions occur under two exploration modes: active and passive. In this paper, we present a series of experiments that evaluate the main perceptual characteristics of both exploration modes. In particular, we focus on haptic shape recognition as it represents a fundamental task in many applications using haptic environments. The results of four experiments conducted with a group of 10 voluntary subjects show that the differences in motor activity between active and passive haptics ease the perception of surfaces for the first case and the perception of pathways for the latter. In addition, the guidance nature of passive haptics makes the pathway direction easy to recognize. This work shows that this last observation could find application in more challenging tasks such as navigation in space.

scholarly journals On Learning Sets of Symmetric Elements (Extended Abstract)

2021 ◽  
Author(s):  
Haggai Maron ◽  
Or Litany ◽  
Gal Chechik ◽  
Ethan Fetaya
Keyword(s):  
Shape Recognition ◽  
Point Clouds ◽  
Approach To Learning ◽  
Series Of Experiments ◽  
The Common ◽  
Equivariant Functions ◽  
Siamese Networks ◽  
Universal Approximators ◽  
Learning Architectures ◽  
Learning Sets

Learning from unordered sets is a fundamental learning setup, recently attracting increasing attention. Research in this area has focused on the case where elements of the set are represented by feature vectors, and far less emphasis has been given to the common case where set elements themselves adhere to their own symmetries. That case is relevant to numerous applications, from deblurring image bursts to multi-view 3D shape recognition and reconstruction. In this paper, we present a principled approach to learning sets of general symmetric elements. We first characterize the space of linear layers that are equivariant both to element reordering and to the inherent symmetries of elements, like translation in the case of images. We further show that networks that are composed of these layers, called Deep Sets for Symmetric Elements layers (DSS), are universal approximators of both invariant and equivariant functions, and that these networks are strictly more expressive than Siamese networks. DSS layers are also straightforward to implement. Finally, we show that they improve over existing set-learning architectures in a series of experiments with images, graphs, and point clouds.

scholarly journals Analysis and 2D numerical modeling of burn through of metallic foil experiments using power KrF and Nd lasers

1999 ◽  
Vol 17 (4) ◽  
pp. 753-758 ◽  
Author(s):  
I.G. LEBO ◽  
Yu.A. MIKHAILOV ◽  
V.F. TISHKIN ◽  
V.D. ZVORYKIN
Keyword(s):  
Laser Energy ◽  
Lebedev Physical Institute ◽  
Foil Thickness ◽  
Rear Side ◽  
Single Beam ◽  
First Case ◽  
Laser Facility ◽  
Series Of Experiments ◽  
Burn Through ◽  
Different Thickness

Two series of experiments on laser irradiation of the different thickness Al-foils were made using laser facilities “GARPUN” and “PICO” (Lebedev Physical Institute, Moscow). “GARPUN” is the KrF-laser with pulse energy Elas ≈ 100 J and pulse duration τ ≈ 100 ns. “PICO” is a Nd-laser facility. The laser energy is Elas1 ≈ 20 J and τ ≈ 3–4 ns in a single beam. The burn through time (tb) of different thickness foils was studied. We have varied the foil thickness: d = 20–500 μm for “GARPUN” facility experiments, and d = 3–12 μm for the case of “PICO” experiments. It was discovered that the rates of the foil burn through are much higher than those obtained in (Dahmani et al., 1991a,b). The experimental data were analyzed with the help of 2D numerical simulations, using the 2D Euler code “NUTCY.” Good agreement was obtained between numerical and experimental results. In the first case the rate of foil “enlightment” is defined by transversal displacement of matter (“drilling effect”). With allowance for the effect of “hot spots formations” it was possible to explain the burn through of thick foils and low laser energy at the rear side of films in “PICO” facility experiments (“microdrilling effect”). The methods of the diminishing of the influence of microdrilling effect (or “imprint” effect) on the nonuniformity of ablation pressure are discussed.

scholarly journals The Casting Molds for Celts of Type IV (Early Iron Age) According to M. P. Gryaznov’s Classification: The Manufacturing Technology

2021 ◽  
Vol 20 (7) ◽  
pp. 97-108
Author(s):  
Dmitriy A. Nenakhov
Keyword(s):  
Iron Age ◽  
Early Iron Age ◽  
Application Technology ◽  
Distinctive Features ◽  
Central Siberia ◽  
Common Features ◽  
Central Figure ◽  
Type Iv ◽  
First Case ◽  
Series Of Experiments

Purpose. Recently there was a publication devoted to the ornament typology, based on a stylized ‘hoof print’, for the Early Iron Age celts from Central Siberia. In developing this ornament typology and identifying its application traditions, the author carried out a series of experiments in order to identify the complete technological cycle of its production. It is this aspect which will be the focus of the article. Results. We are researching the application technology of the ornament that consists of three main elements that make up the composition. In the central part there is a punctum in the form of a stylized unfolded ‘hoof print’. This figure is crossed by a ‘belt’ line. From the top of the ‘hoof print’ and the so-called ‘belt’, short lines can go down. The information on the area, where the celts with such an ornament were found, indicates that they were distributed only in Central Siberia. Conclusion. The complex of objects includes more than 30 celts (Type IV according to M. P. Gryaznov’s typology). The study identifies two traditions of applying an ornament. In the first case, the central figure (‘hoof print’) was cut out on the celt pattern and the impression was transferred to the valve of the casting mold. The rest of the elements were cut out on the casting matrix. In the second case, we are talking about a combined approach, when the ornament was completely applied to the clay model of the celt. At the same time, only the central figure in the form of an unfolded ‘half-hoof print’ was cut out, the rest of the ornament elements such as a ‘belt’ and the hanging short lines were applied using the sculpting method. For both methods of ornament application, there are common features such as the traces of carving with a sharp object (i.e. knife) in the central part of the ‘half-hoof print’ figure, rubbing the sampler surface and the celt shape with the finger pads. The first method’s distinctive features are the roll sculpturing on a celt pattern, superimposing them on top of each other, an overlap of the roll onto the sides. The second method’s distinctive features are the tracing lines made with a pointed object (i.e. wood chips, knife), superposition of carved lines on top of each other.

Starfruit Shape Defect Estimation Based on Concave and Convex Area of a Closed Planar Curve

2012 ◽  
Author(s):  
Musa Mokji ◽  
Syed Abd. Rahman Syed Abu Bakar
Keyword(s):  
Critical Points ◽  
Shape Representation ◽  
Shape Recognition ◽  
Statistical Features ◽  
First Case ◽  
Planar Curve ◽  
Defect Estimation ◽  
Curvature Estimation ◽  
Shape Curve ◽  
Input Curve

Dalam kertas kerja ini, sebuah perwakilan bentuk berdasarkan kawasan cekung dan cembung di sepanjang keluk tertutup dipersembahkan. Teknik yang dicadangkan dalam kertas kerja ini melibatkan proses anggaran kekelukan daripada keluk masukan dan juga proses pencarian titik kritikal pada keluk masukan tersebut. Dengan mengasingkan titik kritikal tersebut kepada kategori cekung dan cembung, pengiraan kawasan cekung dan cembung dilakukan. Daripada ciri–ciri statistik ini, dua permasalahan berkaitan dengan bentuk disiasat. Di sini, teknik yang dicadangkan diuji terhadap proses penganggaran kerosakan bentuk dan pengenalan bentuk pada buah belimbing. Pada kes pertama, kerosakan bentuk belimbing diukur dengan mengira kuasa cekung di mana kuasa cekung ini adalah selanjar dengan kerosakan bentuk tersebut. Untuk kes pengenalpastian bentuk pula, tangkai belimbing adalah objek untuk dikenal pasti dan tangkai belimbing ini akan diasingkan daripada bentuk belimbing kerana ia akan menyumbang kepada kesalahan pengiraan kerosakan bentuk belimbing. Bagi kedua–dua kes, teknik yang dicadangkan diuji dengan tiga teknik penganggaran kekelukan untuk memastikan keberkesanan teknik yang dicadangkan. Kata kunci: Perwakilan bentuk, kekelukan, titik kritikal, kawasan cekung dan cembung In this paper, a shape representation based on concave and convex area along a closed curve is presented. The proposed technique involves the process of the curvature estimation from the input curve and search for its corresponding critical points. By splitting the critical points into concave and convex categories, the concave and convex area are computed. From these statistical features, two problems related to the shape (curve) are investigated. Here, the proposed technique is tested on shape defect estimation and shape recognition of starfruit. In the first case, defect is measured by computing concave energy, which is proportional to the defect. For shape recognition, starfruit’s stem is identified and removed from the starfruit’s shape, as it will contributes false computation of defect measurement. For both cases, the proposed technique is tested with three different curvature estimation techniques to validate the results. Key words: Shape representation, curvature, critical point, concave and convex area

Effect of Packet Loss on Collaborative Haptic Interactions in Networked Virtual Environments: An Experimental Study

2013 ◽  
Vol 22 (1) ◽  
pp. 36-53 ◽  
Author(s):  
Jing Qin ◽  
Kup-Sze Choi ◽  
Renheng Xu ◽  
Wai-Man Pang ◽  
Pheng-Ann Heng
Keyword(s):  
Virtual Environments ◽  
Packet Loss ◽  
Loss Rate ◽  
Packet Loss Rate ◽  
Haptic Interaction ◽  
Haptic Interactions ◽  
Single User ◽  
Subjective Measurements ◽  
Series Of Experiments ◽  
Interactive Task

It has been widely demonstrated that haptic interaction can enrich the sense of copresence of distributed users and improve their performance in collaborative virtual environments (CVEs). However, the influence of network traffic on haptic collaboration, particularly packet loss in haptic data streams, is still largely unknown. In order to investigate this effect, we designed and conducted a series of experiments on a simulated lossy network. First, a single-user interactive task was designed to estimate the just- noticeable packet loss threshold in terms of the length of burst loss (LBL). Second, a CVE was developed in which two users are required to work together on a goal-directed task through haptic collaboration. Experiments were performed to evaluate the users' task performance at different packet loss rates and their perception using subjective measurements. Finally, the effect of packet loss combined with network latency was investigated. The findings are: (1) the threshold LBL value for haptic discontinuity to become noticeable is 60.18 ms; (2) haptic collaboration performance is sensitive to packet loss rate; and (3) while the combined effect of packet loss and communication delay adversely affects collaborative haptic interactions, the influence due to packet loss rate is dominant when the delay is below a certain threshold. These results can serve as a guiding reference for the design and development of virtual telepresence systems with rich haptic collaborations.

Software Module for Objects Shape Tracing and Recognition before Gripping

2012 ◽  
Vol 463-464 ◽  
pp. 1165-1168 ◽  
Author(s):  
Ionel Staretu ◽  
Alexandru Mihail Itu
Keyword(s):  
3D Model ◽  
Human Factor ◽  
Shape Recognition ◽  
General Structure ◽  
Video Camera ◽  
External Factors ◽  
Light Conditions ◽  
Software Module ◽  
Series Of Experiments

This paper presents the general structure, implementation features and a software module for tracing, visualization, shape recognition, measurement and efficiency evaluation for 3D model generation of objects to grip by an anthropomorphic gripper. Viewing is possible with an advanced video camera and shape recognition is possible through classifiers method. After setting the object shape, the gripper will approach the target, and its displacement is measured. Implementation, and how to work with the software designed are possible in several steps that are specified and described. The performance evaluation of the software system is based on a series of external factors, the most important being: light conditions; quality of video device; capture size; the human factor through a series of experiments focused on the system's ability to cope with external factors above mentioned.

Hemoglobin crystals of the red blood cells in the human renal cortex: electron microscopic observations of the renal lithiasis

1978 ◽  
Vol 36 (2) ◽  
pp. 480-481
Author(s):  
Kosuke Ueda ◽  
Hiroto Washida ◽  
Nakazo Watari
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Renal Cortex ◽  
Uranyl Acetate ◽  
Osmic Acid ◽  
Renal Lithiasis ◽  
Electron Microscopic ◽  
Hemoglobin C ◽  
First Case ◽  
Ultrathin Sections

IntroductionHemoglobin crystals in the red blood cells were electronmicroscopically reported by Fawcett in the cat myocardium. In the human, Lessin revealed crystal-containing cells in the periphral blood of hemoglobin C disease patients. We found the hemoglobin crystals and its agglutination in the erythrocytes in the renal cortex of the human renal lithiasis, and these patients had no hematological abnormalities or other diseases out of the renal lithiasis. Hemoglobin crystals in the human erythrocytes were confirmed to be the first case in the kidney.Material and MethodsTen cases of the human renal biopsies were performed on the operations of the seven pyelolithotomies and three ureterolithotomies. The each specimens were primarily fixed in cacodylate buffered 3. 0% glutaraldehyde and post fixed in osmic acid, dehydrated in graded concentrations of ethanol, and then embedded in Epon 812. Ultrathin sections, cut on LKB microtome, were doubly stained with uranyl acetate and lead citrate.

Electron-diffraction studies in synthetic polymer materials

1983 ◽  
Vol 41 ◽  
pp. 362-365
Author(s):  
D.T. Grubb
Keyword(s):  
Electron Diffraction ◽  
Synthetic Polymer ◽  
Polymer Materials ◽  
Crystallographic Structure ◽  
High Dose ◽  
Electron Dose ◽  
Dose Rates ◽  
First Case ◽  
Diffraction Patterns ◽  
The Many

Diffraction studies in polymeric and other beam sensitive materials may bring to mind the many experiments where diffracted intensity has been used as a measure of the electron dose required to destroy fine structure in the TEM. But this paper is concerned with a range of cases where the diffraction pattern itself contains the important information.In the first case, electron diffraction from paraffins, degraded polyethylene and polyethylene single crystals, all the samples are highly ordered, and their crystallographic structure is well known. The diffraction patterns fade on irradiation and may also change considerably in a-spacing, increasing the unit cell volume on irradiation. The effect is large and continuous far C94H190 paraffin and for PE, while for shorter chains to C 28H58 the change is less, levelling off at high dose, Fig.l. It is also found that the change in a-spacing increases at higher dose rates and at higher irradiation temperatures.

X-ray microanalysis of thin specimens in the transmission electron microscope at voltages up to 1000 Kv.

1978 ◽  
Vol 36 (1) ◽  
pp. 540-541
Author(s):  
G. Cliff ◽  
M.J. Nasir ◽  
G.W. Lorimer ◽  
N. Ridley
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Weight Fraction ◽  
Present Series ◽  
Constant Independent ◽  
X Ray ◽  
Transmission Electron ◽  
Series Of Experiments ◽  
Image Position ◽  
X Ray Absorption

In a specimen which is transmission thin to 100 kV electrons - a sample in which X-ray absorption is so insignificant that it can be neglected and where fluorescence effects can generally be ignored (1,2) - a ratio of characteristic X-ray intensities, I1/I2 can be converted into a weight fraction ratio, C1/C2, using the equationwhere k12 is, at a given voltage, a constant independent of composition or thickness, k12 values can be determined experimentally from thin standards (3) or calculated (4,6). Both experimental and calculated k12 values have been obtained for K(11<Z>19),kα(Z>19) and some Lα radiation (3,6) at 100 kV. The object of the present series of experiments was to experimentally determine k12 values at voltages between 200 and 1000 kV and to compare these with calculated values.The experiments were carried out on an AEI-EM7 HVEM fitted with an energy dispersive X-ray detector.

Small-Angle Electron Scattering (SAES) of Polymers

1985 ◽  
Vol 43 ◽  
pp. 78-79
Author(s):  
Ralph Oralor ◽  
Pamela Lloyd ◽  
Satish Kumar ◽  
W. W. Adams
Keyword(s):  
Electron Scattering ◽  
Small Angle ◽  
Angular Resolution ◽  
Structural Features ◽  
Objective Lens ◽  
High Angular Resolution ◽  
Push Button ◽  
First Case ◽  
Diffraction Mode ◽  
Very High

Small angle electron scattering (SAES) has been used to study structural features of up to several thousand angstroms in polymers, as well as in metals. SAES may be done either in (a) long camera mode by switching off the objective lens current or in (b) selected area diffraction mode. In the first case very high camera lengths (up to 7Ø meters on JEOL 1Ø ØCX) and high angular resolution can be obtained, while in the second case smaller camera lengths (approximately up to 3.6 meters on JEOL 1Ø ØCX) and lower angular resolution is obtainable. We conducted our SAES studies on JEOL 1ØØCX which can be switched to either mode with a push button as a standard feature.

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