Active Tactile Exploration Based on Cost-Aware Information Gain Maximization

2018 ◽  
Vol 15 (01) ◽  
pp. 1850015 ◽  
Author(s):  
Simon Ottenhaus ◽  
Lukas Kaul ◽  
Nikolaus Vahrenkamp ◽  
Tamim Asfour

Active tactile perception is a powerful mechanism to collect contact information by touching an unknown object with a robot finger in order to enable further interaction with the object or grasping of the object. The acquired object knowledge can be used to build object shape models based on such usually sparse tactile contact information. In this paper, we address the problem of object shape reconstruction from sparse tactile data gained from a robot finger that yields contact information and surface orientation at the contact points. To this end, we present an exploration algorithm which determines the next best touch target in order to maximize the estimated information gain and to minimize the expected costs of exploration actions. We introduce the Information Gain Estimation Function (IGEF), which combines different goals as measure for the quantification of the cost-aware information gain during exploration. The IGEF-based exploration strategy is validated in simulation using 48 publicly available object models and compared to state-of-the-art Gaussian processes-based exploration approaches. The results show the performance of the approach regarding exploration efficiency, cost-awareness and suitability for application in real tactile sensing scenarios.

2020 ◽  
Vol 32 (5) ◽  
pp. 958-976
Author(s):  
Junya Tanaka ◽  
Nobuto Matsuhira ◽  
◽  

We propose a robotic finger with an exoskeleton-type structure that bends and extends by the deformation force of flat tubes. Our objective is to realize a disposable robot hand for gripping unsanitary objects. To reduce the cost of disposing of the robotic finger, a commercially available cable carrier chain was used for the exoskeleton component, and the flat tubes used in the pneumatic actuator were prepared by thermal processing of a commercially available tube. The driving joint of the robotic finger consists of a hollow link mechanism and two flat tubes, which are respectively arranged inside the hollow link mechanism and at the joint boundary. The proposed joint structure achieves both smooth drivability and good load-bearing capacity. The developed robotic finger weighs approximately 85 g and generates a fingertip force of approximately 4 N when a pressure of 0.25 MPa is applied. Because the developed robotic finger is pneumatically driven, it conforms to the object shape and is compliant to external force. Verification of the mechanism demonstrated that the developed robotic finger is useful because it was able to grasp six types of assumed objects.


Author(s):  
V. N. Kostin

The article deals with the modernization of the structure of physical protection by choosing effective solutions. A feature of the solution of the problem is the use of Markov circuits to model the functioning of physical protection and experiment theory in order to obtain an efficiency function to determine the rational version of modernization of the physical protection structure. Each perpetrator 's path and physical defense response to penetration was modeled by two information-linked Markov chains. The first chain is the intruder penetration path, the second chain is the physical protection response to penetration. An indicator of the effectiveness of physical protection is the probability of finding the information of a critical object in a safe state (probability of fulfilling the functional purpose of physical protection). A general assessment of the security of information was made based on the most pessimistic result of the physical protection response to the intruder 's penetration. An active factor experiment was conducted on the Markov model of physical protection functioning. The factors of the experiment are structural changes in engineering equipment for physical protection, aimed at improving the efficiency of information protection. According to the results of the factor experiment on the Markovsky model, the response function was obtained - the increment of the efficiency of physical protection to the cost of modernization costs. Based on the analysis of the obtained response function to achieve the maximum increment of the efficiency/cost function, the center of the experiment plan shifted towards the maximum function factor by an amount providing predetermined physical protection efficiency requirements. Thus, a mathematically sound way of structural modernization of physical protection is proposed, as well as parameters of structural modernization ensuring the required efficiency.


2021 ◽  
Vol 33 ◽  
pp. 04006
Author(s):  
Rahmi Wahyuni ◽  
R.A. Dewi ◽  
Harmaini ◽  
S. Asmairicen

The main problem in the development of cattle business people in palm plantation, one exeption availibility of forage animal feed whether in quantity n quality. Other side the existence of palm leaves the midrib has been waste of a disturbing and not been utilized by farmers. To the touch technological innovations feed in te form of silage then palm leaves the midrib has been animal feed worthy of in eating of cattle. The purpose of this research is identify the effects the provisio of feed based silage palm leaves midrib increased body weight on cattle beef and analyzing efficiency the cost of animal feed. Research in farmer group Tanjung Keramat in district Kinali, Pasaman Barat in february until april 2017. Respondent are set down in purposive sampling. This research used 18 tail local bulls created the average 2 until 2, 5 years. Treatment provides was P1 control grass field is 10% from body weght (25 Kg) + bran is 10% from body weght (2,5 Kg) , P2 granting of silage then palm leaves (10 kg) + bran (1,5 Kg) + gliserida ( 2 Kg). In an analysis using t tableindependent sample t-testα=5%. Result of research shows P1 increase body weight cattle 0,68 kg/tail/day and P2 0,81 kg/ tail/ day . Provision of feed based silage then palm leaves significant compared feed control t test (-6,9) > t tabel (2,4). With efficiency cost feed during 90 days P1 (Rp. 967.500,-/cattle) and P2 (Rp. 675.500,-/cattle). So, with provision palm leaves besides increasing body weight cattle, can also reducing the grass that drain time dan energy can reduce the cost daily cattle feed.


2019 ◽  
Author(s):  
Haoyang Lu ◽  
Li Yi ◽  
Hang Zhang

AbstractInformation sampling can reduce uncertainty in future decisions but is often costly. To maximize reward, people need to balance sampling cost and information gain. Here we aimed to understand how autistic traits influence the optimality of information sampling and to identify the particularly affected cognitive processes. Healthy human adults with different levels of autistic traits performed a probabilistic inference task, where they could sequentially sample information to increase their likelihood of correct inference and may choose to stop at any moment. We manipulated the cost and evidence associated with each sample and compared participants’ performance to strategies that maximize expected gain. We found that participants were overall close to optimal but also showed autistic-trait-related differences. Participants with higher autistic traits had a higher efficiency of winning rewards when the sampling cost was zero but a lower efficiency when the cost was high and the evidence was more ambiguous.Computational modeling of participants’ sampling choices and decision times revealed a two-stage decision process, with the second stage being an optional second thought. Participants may consider cost in the first stage and evidence in the second stage, or in the reverse order. The probability of choosing stopping at a specific stage increases with increasing cost or increasing evidence. Surprisingly, autistic traits did not influence the decision in either stage. However, participants with higher autistic traits inclined to consider cost first, while those with lower autistic traits considered cost or evidence first in a more balanced way. This would lead to the observed autistic-trait-related advantages or disadvantages in sampling optimality, depending on whether the optimal sampling strategy is determined only by cost or jointly by cost and evidence.Author SummaryChildren with autism can spend hours practicing lining up toys or learning all about cars or lighthouses. This kind of behaviors, we think, may reflect suboptimal information sampling strategies, that is, a failure to balance the gain of information with the cost (time, energy, or money) of information sampling. We hypothesized that suboptimal information sampling is a general characteristic of people with autism or high level of autistic traits. In our experiment, we tested how participants may adjust their sampling strategies with the change of sampling cost and information gain in the environment. Though all participants were healthy young adults who had similar IQs, higher autistic traits were associated with higher or lower efficiency of winning rewards under different conditions. Counterintuitively, participants with different levels of autistic traits did not differ in the general tendency of oversampling or undersampling, or in the decision they would reach when a specific set of sampling cost or information gain was considered. Instead, participants with higher autistic traits consistently considered sampling cost first and only weighed information gain during a second thought, while those with lower autistic traits had more diverse sampling strategies that consequently better balanced sampling cost and information gain.


Electronics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1441 ◽  
Author(s):  
Tim Collins ◽  
Sandra I. Woolley ◽  
Erlend Gehlken ◽  
Eugene Ch’ng

The photogrammetric acquisition of 3D object models can be achieved by Structure from Motion (SfM) computation of photographs taken from multiple viewpoints. All-around 3D models of small artefacts with complex geometry can be difficult to acquire photogrammetrically and the precision of the acquired models can be diminished by the generic application of automated photogrammetric workflows. In this paper, we present two versions of a complete rotary photogrammetric system and an automated workflow for all-around, precise, reliable and low-cost acquisitions of large numbers of small artefacts, together with consideration of the visual quality of the model textures. The acquisition systems comprise a turntable and (i) a computer and digital camera or (ii) a smartphone designed to be ultra-low cost (less than $150). Experimental results are presented which demonstrate an acquisition precision of less than 40 μ m using a 12.2 Megapixel digital camera and less than 80 μ m using an 8 Megapixel smartphone. The novel contribution of this work centres on the design of an automated solution that achieves high-precision, photographically textured 3D acquisitions at a fraction of the cost of currently available systems. This could significantly benefit the digitisation efforts of collectors, curators and archaeologists as well as the wider population.


2021 ◽  
Vol 149 (4) ◽  
pp. 921-944
Author(s):  
John R. Lawson ◽  
Corey K. Potvin ◽  
Patrick S. Skinner ◽  
Anthony E. Reinhart

AbstractTornadoes have Lorenzian predictability horizons O(10) min, and convection-allowing ensemble prediction systems (EPSs) often provide probabilistic guidance of such events to forecasters. Given the O(0.1)-km length scale of tornadoes and O(1)-km scale of mesocyclones, operational models running at horizontal grid spacings (Δx) of 3 km may not capture narrower mesocyclones (typical of the southeastern United States) and certainly do not resolve most tornadoes per se. In any case, it requires O(50) times more computer power to reduce Δx by a factor of 3. Herein, to determine value in such an investment, we compare two EPSs, differing only in Δx (3 vs 1 km), for four low-CAPE, high-shear cases. Verification was grouped as 1) deterministic, traditional methods using pointwise evaluation, 2) a scale-aware probabilistic metric, and 3) a novel method via object identification and information theory. Results suggest 1-km forecasts better detect storms and any associated rapid low- and midlevel rotation, but at the cost of weak–moderate reflectivity forecast skill. The nature of improvement was sensitive to the case, variable, forecast lead time, and magnitude, precluding a straightforward aggregation of results. However, the distribution of object-specific information gain over all cases consistently shows greater average benefit from the 1-km EPS. We also reiterate the importance of verification methodology appropriate for the hazard of interest.


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