Development and testing of a novel image analysis algorithm for descriptive evaluation of shape change of a shrinkable soft material

Soft material can undergo non-uniform deformation or change of shape upon processing. Identifying shape and its change is nevertheless not straightforward. In this study, novel image-based algorithm that can be used to identify shapes of input images and at the same time classify non-uniform deformation into various patterns, i.e., swelling/shrinkage, horizontal and vertical elongations/contractions as well as convexity and concavity, is proposed. The algorithm was first tested with computer-generated images and later applied to agar cubes, which were used as model shrinkable soft material, undergoing drying at different temperatures. Shape parameters and shape-parameter based algorithm as well as convolutional neural networks (CNNs) either incorrectly identified some complicated shapes or could only identify the point where non-uniform deformation started to take place; CNNs lacked ability to describe non-uniform deformation evolution. Shape identification accuracy of the newly developed algorithm against computer-generated images was 65.88%, while those of the other tested algorithms ranged from 34.76 to 97.88%. However, when being applied to the deformation of agar cubes, the developed algorithm performed superiorly to the others. The proposed algorithm could both identify the shapes and describe their changes. The interpretation agreed well with that via visual observation.

SCALING PROPERTIES OF QUEUES WITH TIME-VARYING LOAD PROCESSES: EXTENSIONS AND APPLICATIONS

New computing and communications paradigms will result in traffic loads in information server systems that fluctuate over much broader ranges of time scales than current systems. In addition, these fluctuation time scales may only be indirectly known or even be unknown. However, we should still be able to accurately design and manage such systems. This paper addresses this issue: we consider an M/M/1 queueing system operating in a random environment (denoted M/M/1(R)) that alternates between HIGH and LOW phases, where the load in the HIGH phase is higher than in the LOW phase. Previous work on the performance characteristics of M/M/1(R) systems established fundamental properties of the shape of performance curves. In this paper, we extend monotonicity results to include convexity and concavity properties, provide a partial answer to an open problem on stochastic ordering, develop new computational techniques, and include boundary cases and various degenerate M/M/1(R) systems. The basis of our results are novel representations for the mean number in system and the probability of the system being empty. We then apply these results to analyze practical aspects of system operation and design; in particular, we derive the optimal service rate to minimize mean system cost and provide a bias analysis of the use of customer-level sampling to estimate time-stationary quantities.

Virtual Fixture Generation for Task Planning with Complex Geometries

Many robotic processes require the system to maintain a tool's orientation and distance from a surface. To do so, researchers often use Virtual Fixtures (VFs) to either guide the robot along a path or forbid it from leaving the workspace. Previous efforts relied on volumetric primitives (planes, cylinders, etc.) or raw sensor data to define VFs. However, those approaches only work for a small subset of real-world objects. Extending this approach is complicated not only by VF generation but also generalizing user traversal of the VF to command a robot trajectory remotely. In this work, we present the concept of Task VFs, which convert layers of point cloud based Guidance VF into a bidirectional graph structure and pair it with a Forbidden Region VF. These VFs are hardware-agnostic and can be generated from virtually any source data, including from parametric objects (superellipsoids, supertoroids, etc.), meshes (including from CAD), and real-time sensor data for open-world scenarios. We address surface convexity and concavity since these and distance to the task surface determine the size and resolution of VF layers. This paper then presents the Manipulator-to-Task Transform Tool for Task VF visualization and to limit human-robot interaction ambiguities. Testing confirmed generation success, and users performed spatially discrete experiments to evaluate Task VF usability complex geometries, which showed their interpretability. The Manipulator-to-Task Transform Tool applies many robotic applications, including collision avoidance, process design, training, task definition, etc. for virtually any geometry.

Open quantum systems and thermal non-equilibrium processes

In this paper, we investigate the effects of convexity and concavity of states on entanglement of the system under thermal non-equilibrium condition. In this regard, we consider a system consisting of two spin 1/2 particles with Dzyaloshinskii–Moriya (DM) interaction that follows the Tsallis statistics.Also, according to the desired statistics, the effect of environment parameters and the convexity or concavity of the input states on the output behavior of the SWAP gate is obtained.

A new branch and bound algorithm for minimax ratios problems

This study presents an efficient branch and bound algorithm for globally solving the minimax fractional programming problem (MFP). By introducing an auxiliary variable, an equivalent problem is firstly constructed and the convex relaxation programming problem is then established by utilizing convexity and concavity of functions in the problem. Other than usual branch and bound algorithm, an adapted partition skill and a practical reduction technique performed only in an unidimensional interval are incorporated into the algorithm scheme to significantly improve the computational performance. The global convergence is proved. Finally, some comparative experiments and a randomized numerical test are carried out to demonstrate the efficiency and robustness of the proposed algorithm.

CONVEXITY AND CONCAVITY OF MEANS

In this paper, convexity and concavity among Greek means are discussed and the results are interpreted with Vander monde's determinant.