Young Bong Seo

Distributed single target tracking in underwater wireless sensor networks

The growing interests in underwater wireless sensor networks(UWSNs) for a wide variety of purposes from Tsunami monitoring to commercial oilfield exploration projects have been encouraging. This paper deals with the problem of accurately tracking a single target moving through UWSNs employing acoustic sensors. This paper addresses the issues of estimating the target position, improving energy efficiency by applying a Kalman filter in a distributed architecture. Each underwater wireless sensor nodes composing the UWSNs is battery-powered, so the energy conservation problem is a critical issue. This paper provides an algorithm which increases energy efficiency of each sensor through a wake-up/sleep(WuS) and a valid measurement selecting(VMS) scheme. Simulation results illustrate the performance of the tracking filter according to the sensor node displacement and sensor detecting area.

ToA based sensor localization in underwater wireless sensor networks

Currently several kinds of sensor localization methods have been developed for terrestrial wireless sensor networks. In this paper, in order to extend the field to underwater environments, we study sensor localization technique for underwater wireless sensor networks(UWSNs). In underwater environments, radio frequency(RF) signal is not suitable for underwater usage because of extremely limited propagation. Because of that reason UWSNs should be constituted with acoustic modems. So we need a new localization algorithm to determine each sensors position. First of all we study the localization techniques for terrestrial environments where we investigate possible methods to underwater environment. And then we present the appropriate algorithm in the underwater usage. Finally we, evaluate the underwater based localization algorithm using computer based different conditions among communication range of sensor node, the nodes number and position of reference node.

Overlapping decentralized EA control design for an active suspension system of a full car model

A decentralized eigenstructure assignment (EA) controller is designed for an active suspension system of a vehicle based on a 7-degree of freedom full car model. Using overlapping decomposition, the full car model is decentralized by two half car models. For each half car model, for the disturbance which is caused by the overlapping decomposition, an effective suppressible controller can be obtained by assigning the left eigenstructure of the system. The performance of the decentralized EA controller is compared with that of a conventional centralized EA controller through computer simulations.

Frequency domain properties of EALQR with indefinite weighting matrix

EALQR (Linear Quadratic Regulator design with Eigenstructure Assignment capability) has the capability of exact assignment of eigenstructure with the guaranteed margins of the LQR for MIMO (Multi-Input Multi-Output) systems. However, EALQR undergoes a restriction on the state-weighting matrixQ in LQR to be indefinite with respect to the region of allowable closed-loop eigenvalues. The definiteness of the weighting matrix is closely related to the robustness property of a given system. In this paper, we derive a relation between the indefinite weighting matrix Q and the robustness property for EALQR. The modified frequency domain inequality, that could be guaranteed by EQLQR with an indefinite weighting matrix, is presented.

Analysis of EALQR control design methodology

EALQR (linear quadratic regulator with an eigenstructure assignment capability), a control design methodology previously developed by the authors, performs better than a conventional LQR or an eigenstructure assignment. However, it has a constraint on the weighting matrix, that is, the weighting matrix can be indefinite for some high-order systems. This paper analyzes the effects of an indefinite weighting matrix in EALQR on the frequency domain properties. The robustness criterion and the quantitative frequency domain properties are presented. The frequency domain properties of EALQR with an indefinite weighting matrix have been analyzed by applying them to a flight control system as a design example.

Sliding Mode Control for Autonomous Underwater Vehicle under Open Control Platform environment

This paper discusses the feature of an autonomous underwater vehicle (AUV) using sliding mode control (SMC) under the open control platform (OCP). Considering with the torpedo model in AUV test-bed, SMC is chosen to control the diving and steering maneuver of the AUV. This experiment uses ACE/TAO real-time event channel (RTEC) as a middleware platform for enabling control and communication in the AUV test-bed development. In this paper, two computers are used in the experiment, and each of it is dedicated for specific purpose in the AUV system. The first computer is used for AUV dynamics. The second computer used as SMC controller module. Finally, we evaluate the performance of SMC in the proposed environment.

Eigenstructure assignment for LTI systems with stochastic parameter variations

In this paper, we present a method that has the capability of exact assignment of eigenstructure with the stochastic robustness for LTI (linear time-invariant) systems. The stochastic robustness of LTI systems is determined by the probability distributions of closed-loop eigenvalues. The stability region for a system is presented stochastically based upon the Monte Carlo evaluations. The proposed scheme is applied to designing a simple system and a flight control system with stochastic parameter variations to confirm the usefulness of the scheme.

A PNU model of engineering service learning as a multidisciplinary design project

Multidisciplinary design projects that require students to travel to other countries, especially under-developed countries have the potential to provide very powerful learning experiences to students. In this paper, a PNU model of engineering service learning as a multidisciplinary design project is presented. The key features of the model are in the 1) proposition of creative ideas for a specific region of an under-developed country, Indonesia, by multidisciplinary project winner teams that applied to the ‘Engineering Service Idea Competition’, 2) development of model pilots which are supposed to be installed in the specific site with the proposed ideas, and 3) outreach in Indonesia to install the developed systems. The first two steps of this project are performed at PNU(Pusan National University) in Korea and ITS(Institute of Technology Sepuluh Nopember) in Indonesia independently, on the while, the outreach as the final step of the project to the site is conducted by the internationally mixed teams of the two institutions.

Home network development based on CORBA middleware

In this paper we propose a home network infrastructure based on CORBA middleware in order to enable the connection and integration of multiple home devices by giving communication, control, monitoring, and management services. The home networks connections and services are developed based on the CORBA event channel using client-server configuration. Several functions are developed in the home network such as; remote controlling, remote monitoring, manual or automatic device configuration and devices management. Several services and functions are provided to examine the network performance. The proposed design is evaluated using a testbed based on the PLC Ethernet and Wi-Fi communication media. Finally, network connection from small number of clients until one hundred clients also has been simulated to observe the overall performance.

Control design methodology using EALQR

A relation between the weighting matrix Q in LQR and the eigenstructure of the desired closed-loop system is proposed. Thus, the state feedback gain with the desired eigenstructure in the LQR can be obtained. The proposed scheme is applied to designing a simple 3rd-order system and an automotive active suspension control system design to show the usefulness of the scheme.