14,069 research outputs found
Person Wide Web: Active Location based Web Service Architecture using Wireless Infrastructure
No full textThis research is supported by the Ubiquitous Computing and
Network (UCN) project, Knowledge and Economy Frontier
R&D Program of the Ministry of Knowledge Economy (MKE)
in Korea as a result of UCN’s subproject 10C1-T1-20S. And,
we are thankful to Sang-Ok Cho, research staff at Octacomm
Inc. (http://octacomm.net) for his support to our research
Shape optimization of shear fracture specimen considering plastic anisotropy
No full textIt is important to fabricate fracture specimens with minimum variation of triaxiality in order to characterize the failure behaviors experimentally. Fracture in ductile materials is usually calibrated by uniaxial tensile, shear and plane strain tests. However, it is often observed that triaxiality for shear specimen changes severely during shear fracture test. The nonlinearity of triaxiality is most critical for shear test. In this study, a simple in-plane shear specimen is optimized by minimizing the variation of stress triaxiality in the shear zone. In the optimization, the Hill48 and Yld2000-2d criteria are employed to model the anisotropic plastic deformation of an aluminum alloy of 6k21. The evolution of the stress triaxiality of the optimized shear specimen is compared with that of the initial design of the shear specimen. The comparison reveals that the stress triaxiality changes much less for the optimized shear specimen than the evolution of the stress triaxiality with the original design of the shear specimen
A Lightweight and Cost-Effective 3D Omnidirectional Depth Sensor Based on Laser Triangulation
No full textIn this paper, we propose a new lightweight and cost-effective 3D omnidirectional depth sensor based on laser triangulation in order to ensure a wide field of view (FOV) while achieving portability and affordability. The proposed sensor is tiny palm-sized and hence easily installed even on small moving objects, which is largely composed of a structured light-based 2D sensor and a rotating motor for creating a full 360 degree horizontal FOV, thus providing a 3D omnidirectional sensing capability. The structured light-based 2D sensor is specially designed to maximize the vertical FOV by employing a fisheye camera and a laser beam passing through two cylindrical lenses for projecting a line onto a surface. From the rotational movement of the 2D sensor due to the mounted motor, its surroundings are scanned by extracting the corresponding 3D omnidirectional depth information from laser triangulation. The actual implementation is carried out to examine the technical feasibility of realizing the proposed 3D omnidirectioanl depth sensor. It turns out that the proposed depth sensor covers over 97% area of its surrounding sphere. It is also observed through experiments that the proposed 3D omnidirectional depth sensor has similar accuracy to that of a Velodyne HDL-32, 32-channel light detection and ranging (LIDAR) sensor, at a range of 5 m to 6 m while providing much wider vertical FOV and higher vertical resolution.11Ysciescopu
Numerical integration algorithm of updated homogeneous anisotropic hardening model through finite element framework
No full textIn this work, an updated version of the homogeneous anisotropic hardening (HAH20) model proposed by Barlat et al. (2020) is implemented into a finite element framework through a stress integration algorithm. To improve the convergence of this model inside the integration algorithm, the algorithmic step sizes of the solution variable increments are controlled by the line-search method. The HAH20 implementation is validated by comparing the simulation results obtained from the finite element analysis with those calculated by stand-alone HAH20 code. In addition, the simulation results of tests, including strain path changes such as tension-compression and cross-loading, are compared with experimental measurements, and the effectiveness of the step size control in the current HAH20 model is investigated. The performance of the implemented algorithm is analyzed through convergence maps for critical strain path change simulations. (C) 2020 Elsevier B.V. All rights reserved.11Nsciescopu
Expression profile analysis of metabolism of Escherichia coli during high cell density cultivation usng DNA chip
No full textOutput Regulation of Linear Aperiodic Sampled-Data Systems
No full textThis paper deals with the output regulation problem of a linear time-invariant system in the presence of sporadically available measurement streams. A regulator with a continuous intersample injection term is proposed, where the intersample injection is provided by a linear dynamical system and the state of which is reset with the arrival of every new measurement updates. The resulting system is augmented with a timer triggering an instantaneous update of the new measurement and the overall system is then analyzed in a hybrid system framework. With the Lyapunov based stability analysis, we offer sufficient conditions to ensure the objectives of the output regulation problem are achieved under intermittency of the measurement streams. Then, from the solution to linear matrix inequalities, a numerically tractable regulator design procedure is presented. Finally, with the help of an illustrative example, the effectiveness of the theoretical results are validated
Inferring biomolecular interaction networks based on convex optimization
No full textWe present an optimization-based inference scheme to unravel the functional interaction structure of biomolecular components within a cell. The regulatory network of a cell is inferred from the data obtained by perturbation of adjustable parameters or initial concentrations of specific components. It turns out that the identification procedure leads to a convex optimization problem with regularization as we have to achieve the sparsity of a network and also reflect any a priori information on the network structure. Since the convex optimization has been well studied for a long time, a variety of efficient algorithms were developed and many numerical solvers are freely available. In order to estimate time derivatives from discrete-time samples, a cubic spline fitting is incorporated into the proposed optimization procedure. Throughout simulation studies on several examples, it is shown that the proposed convex optimization scheme can effectively uncover the functional interaction structure of a biomolecular regulatory network with reasonable accuracy. (C) 2007 Elsevier Ltd. All rights reserved
Fmax enhancement in InP-based DHBTs using a new lateral reverse-etching technique
No full texta National Program for Tera-Level Nanodevice of the Ministry of Science and Technolog
An efficient identity-based proxy signcryption for secure broadcast
No full textThis research is supported by the Ubiquitous Computing and Network(UCN) Project, Knowledge and Economy Frontier R&D Program of the Ministry of Knowledge Economy(MKE) in Korea as a result of UCNs subproject 10C1-T1-20S
- …
