• Journal of the Korea Safety Management & Science
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• v.12 no.2
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• pp.167-172
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• 2010

EPCIS(EPC Information Service) system is a core component of EPCglobal Architecture Framework offering information of the freights, the time of awareness and the location of awareness on the EPCglobal Network. EPCIS Repository continuously stores and manages mass EPCIS Event input data from a great number of RFID devices simultaneously. The Hybrid DBMS can deal efficiently mass necessary data. This study suggest the plan which can efficiently manage EPCIS Repository using Hybrid DBMS. We offer three schema and stores EPCIS Event data to Altibase DB that can efficiently manage EPCIS Repository using Hybrid DBMS and compare the performance about three schema through simulations.

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.117-122
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• 1998

The recent developments and studies in the framework of output tracking control in the field of robotics that has been studied in the Control Laboratory, are presented. An output controller based on“Hardware-ln-the-Loop Simulation”(HILS) and“Rapid Control Prototyping”(RCP) concepts is developed using dSPACE. These new concepts are shown to be particularly beneficial for manipulator control tasks. In the Elbow manipulator design, there are two kinds of manipulators, namely the serial-drive type and the parallelogram-drive manipulator, The objective of this research is to model the two Elbow manipulators and to implement the proposed controller for manipulator applications. The control goal is to force the manipulator to follow a given trajectory in the given work space. Output controllers of the two elbow manipulators that are based on the model matching control approach have been implemented in two models that represent the robot equations of motion. To reduce the efforts in evaluating the proposed algorithm, a new system configuration method, based on HILS and RCP tools, was suggested to determine the parameters of the integrated dynamic system.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.3
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• pp.237-242
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• 2012

AFC (Adaptive Feedforward Control) is significantly employed for improving control performance of dynamic systems particularly involving periodic disturbance signals in engineering fields. This paper presents a novel hybrid AFC approach for discrete-time systems with multiple disturbances in terms of control input and state variables. The proposed AFC mechanism is hierarchically composed of a conventional feedforward control framework and PID auxiliary control configuration in parallel. The former is generic to decrease periodic disturbance excited to control actuators and the latter is additionally constructed to overcome control deterioration due to time-varying uncertainty under given systems. We carry out numerical simulation to test reliability of our proposed hybrid AFC system and compare its control performance to a well-known conventional AFC method with respect to time and frequency domains for proving of its superiority.

• The Journal of Korean Association of Computer Education
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• v.14 no.5
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• pp.1-8
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• 2011

The purpose of this study is to explore vocational high school students' understanding levels and misconceptions regarding the time-efficiency of algorithms. In this study, a questionnaire with nine questions was developed. The questionnaire is base on three misconceptions about the time-efficiency of algorithms that are examined through prior studies. The questionnaire was applied to 51 students who completed a programming course. The result shows that the students didn't sufficiently understand the concept of time-efficiency of algorithms and several common misconceptions appeared repeatedly. Finally, teaching strategies using simulation and assesment framework for algorithm's time-efficiency were presented and some recommendations were suggested for refining the curriculum relating computer programming and algorithms.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.23 no.3
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• pp.28-34
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• 2015

An analysis method of trajectory prediction has been suggested and the developed trajectory prediction module, which is an important functional component of the Arrival Manager (AMAN) of Jeju airport, has been tested by applying the suggested method. The objective of this method is to improve prediction performance of the trajectory prediction module. The trajectory prediction module predicts the trajectories based on the real-time track data and flight plans. Therefore, the suggested analysis method includes the simulation framework which is based on real-time playback, recording, and graphic display systems for testing. Besides, the definition of time error, which is a important index for the time based scheduling system, such as AMAN, is included in the suggested analysis method. An example of arrival time prediction accuracy improvement through the suggested analysis method has also been presented.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.3B
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• pp.268-274
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• 2011

Recently, we could witness research works on the development of mobile harbor. In line with the implementation of the physical entity for the mobile harbor system, there exists a need for the development of the service management system for the mobile harbor. In this work we propose a framework for the mobile harbor service management system. To that purpose, we first define the principle for the operation of the mobile harbor service management system. Also we develop the mobile harbor service management system by simulation. Finally, we illustrate the implication of the research by experiments.

• Journal of Communications and Networks
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• v.18 no.4
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• pp.600-609
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• 2016

In this paper, we propose a two-stage base station (BS) sleeping scheme to save energy consumption in cellular networks. The BS sleeping mode is divided into a light sleeping stage and a deep sleeping stage according to whether there is a user in the BS's coverage. In the light sleeping stage, a BS will retain its coverage and frequently switch between the on state and the doze state according to the service characteristics. While in the deep sleeping stage analysis, the BS will shut down its coverage, and neighbor BSs will patch the coverage hole. Several closed-form formulas are derived to demonstrate the power consumption in each sleeping stage and the stage switching conditions are discussed to minimize the average power consumption. The average traffic delay caused by BS sleeping and the average deep sleeping rate under a given traffic load have also been studied. In addition, it is shown that BS sleeping is not always possible because of the limited quality of service (QoS) requirements. Simulation results show that the proposed scheme can effectively reduce the average BS power consumption, at the cost of some extra traffic delay. In summary, our proposed framework provides an essential understanding of the design of future green networks that aim to take full advantage of different stages of BS sleeping to obtain the best energy efficiency.

• Smart Structures and Systems
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• v.4 no.6
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• pp.779-794
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• 2008

Observer-based fault detection and isolation (FDI) filter design method is a model-based method. By carefully choosing the observer gain, the residual outputs can be projected onto different independent subspaces. Each subspace corresponds to the monitored structural element so that the projected residual will be nonzero when the associated structural element is damaged and zero when there is no damage. The key point of detection filter design is how to find an appropriate observer gain. This problem can be interpreted in a geometric framework and is found to be equivalent to the problem of finding a decentralized static output feedback gain. But, it is still a challenging task to find the decentralized controller by either analytical or numerical methods because its solution set is, generally, non-convex. In this paper, the concept of detection filter and iterative LMI technique for decentralized controller design are combined to develop an algorithm to compute the observer gain. It can be used to monitor structural element state: healthy or damaged. The simulation results show that the developed method can successfully identify structural damages.

• IE interfaces
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• v.12 no.2
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• pp.193-204
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• 1999

Development of high technology especially in telecommunication and precise weapon systems will impact the future battle field environment. So it is not difficult to anticipate the environment of military command and control system will be changed rapidly. Considering these future battle field environment, military needs automated C4I (Command, Control, Communication, Computer and Intelligence) system, namely real time decision support system which is combined high technologies. Most of advanced countries have been studied and developed these kinds of systems and already applied these systems in real military operations. In order to take a military initiative in Korea peninsula it is essential to catch up with this trend and procure C4I system. The purpose of this research is to present the method and the direction of optimal C4I system development model. First we survey the related theory about C4I systems. Second we present the conceptual framework for C4I system concept development. Third we model the system using Timed Petri-Net and perform simulation. Finally we analyze the through-put time and suggest alternatives. If we model using the real organization structure, operational tasks and various situations then optimal C4I system would be developed.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.2
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• pp.96-105
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• 2004

The recovering 3D image from 2D requires the depth information for each picture element. The manual creation of those 3D models is time consuming and expensive. The goal in this paper is to estimate the relative depth information of every region from single view image with camera translation. The paper is based on the fact that the motion of every point within image which taken from camera translation depends on the depth. Motion vector using full-search motion estimation is compensated for camera rotation and zooming. We have developed a framework that estimates the average frame depth by analyzing motion vector and then calculates relative depth of region to average frame depth. Simulation results show that the depth of region belongs to a near or far object is consistent accord with relative depth that man recognizes.