• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.61.6-61
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• 2002

In these days, Block Pulse functions are used in a variety of fields such as the analysis and controller design of the systems. In applying the Block Pulse function technique to control and systems science, the integral operation of the Block Pulse series plays important roles. This is because differential equations are always involved in the representations of continuous-time models of dynamic systems, and differential operations are always approximated by the corresponding Block Pulse series through integration operational matrices. In order to apply the Block Pulse function technique to the problems of continuous-time dynamic systems more efficiently, it is necessary to find th...

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.1
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• pp.60-67
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• 2004

In this paper, a rectangular ring microstrip patch antenna has been analyzed by using desegmentation method and evaluation impedance matrices from Green's functions fur rectangular segment and desegmentation method for analysis of planar electro-magnetic structures is discussed. As the rectangular ring cavity could be seen as a structure subtracted a small rectangular cavity from a large one, the overall impedance matrix was obtained by applying a multiport connection method to the individual impedance matrices expressed as a term of Green's function fer rectangular segment. The electromagnetic fields can be solved from a vector potential which is satisfied it's eight boundary conditions. The electric field distribution at each edges was expressed as a histogram table with exciting modes. These results can be used to analyze the operational modes for a rectangular ring microstrip antennas.

• Structural Engineering and Mechanics
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• v.67 no.4
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• pp.359-368
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• 2018

In this paper, a method is presented to identify the physical and modal parameters of multistory shear building based on substructural technique using block pulse generalized operational matrix and genetic algorithm. The substructure approach divides a complete structure into several substructures in order to significantly reduce the number of unknown parameters for each substructure so that identification processes can be independently conducted on each substructure. Block pulse functions are set of orthogonal functions that have been used in recent years as useful tools in signal characterization. Assuming that the input-outputs data of the system are known, their original BP coefficients can be calculated using numerical method. By using generalized BP operational matrices, substructural dynamic vibration equations can be converted into algebraic equations and based on BP coefficient for each story can be estimated. A cost function can be defined for each story based on original and estimated BP coefficients and physical parameters such as mass, stiffness and damping can be obtained by minimizing cost functions with genetic algorithm. Then, the modal parameters can be computed based on physical parameters. This method does not require that all floors are equipped with sensor simultaneously. To prove the validity, numerical simulation of a shear building excited by two different normally distributed random signals is presented. To evaluate the noise effect, measurement random white noise is added to the noise-free structural responses. The results reveal the proposed method can be beneficial in structural identification with less computational expenses and high accuracy.

• Journal of the Korean Institute of Landscape Architecture
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• v.15 no.3
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• pp.1-10
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• 1988

The initial selection of plants is the decisive step in the ultimate success of any landscape planting. This study intended to establish a reasonable selecting criteria of tree in the landscape through the holistic consideration of aesthetic, functional, cultural, operational and ecological viewpoints. The matrices of evaluating the fitness of tree were modulated to 10 categories ; availability from the established nursery. aesthetic value, indigenous to the locality, maintenance, soil fertility requirement, environmental tolerances. growth rate. wild-life food production. use of plants in design and user's likes. This 10 categories were weighted to their fitness as high(10 points), medium(8 points) and low(5points). Thus suitable plants were identified which got 70 more points from total 100 points. Such a method was believed as a rational process to get trust from client. to persuade uneducated client and to be free from designer's prejudice through a case study. But it is important to landscape designer to recognize the relationship between the rationality which prevails throughout the modern technical world and the intuitive aspects of design that are essential for developing creative solutions to encourage creativity as well as analytical responsibility.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.5
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• pp.405-412
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• 2015

This paper represents a filter design to estimate the airspeed of a spin-stabilized, trajectory-correctible artillery ammunition. Due to the limited power and space in operational point of view, the airspeed sensor is not installed, and thus the airspeed need to be estimated using limited sensor measurements. The only IMU measurements(three-axis specific forces and angular rates) are used in this application. The extended Kalman filter algorithm is applied since a linear filter can not cover the its wide operational range in airspeed and altitude. In the implementation of the EKF, the state and measurement equations are transformed into the no-roll frame for simple form of Jacobian matrix. The simulation study is conducted to evaluate the performance of the filter under various environment conditions of sensor noise and wind turbulence. In addition, the effect of the choice in filter design parameters, i.e. process error covariance matrices is analyzed on the performance of the estimation of airspeed and angular rates.

• Smart Structures and Systems
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• v.26 no.4
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• pp.419-433
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• 2020

Investigation of structural integrity has been a critical issue in the field of civil engineering for years. Visual inspection is one of the most available methods to explore deteriorative components in structures. Still, this method is not applicable to invisible damage of structures. Alternatively, system identification methods are capable of tracking modal properties of structures over time. The deviation of these dynamic properties can serve as indicators to access structural integrity. In this study, a modal tracking technique using frequency-domain system identification from seismic responses of structures is proposed. The method first segments the measured signals into overlapped sequential portions and then establishes multiple Hankel matrices. Each Hankel matrix is then converted to the frequency domain, and a temporal-average frequency-domain Hankel matrix can be calculated. This study also proposes the frequency band selection that can divide the frequency-domain Hankel matrix into several portions in accordance with referenced natural frequencies. Once these referenced natural frequencies are unavailable, the first few right singular vectors by the singular value decomposition can offer these references. Finally, the frequency-domain stochastic subspace identification tracks the natural frequencies and mode shapes of structures through quick stabilization diagrams. To evaluate performance of the proposed method, a numerical study is carried out. Moreover, the long-term monitoring strong motion records at a specific site are exploited to assess the tracking performance. As seen in results, the proposed method is capable of tracking modal properties through seismic responses of structures.

• Journal of the Korea Society of Computer and Information
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• v.13 no.2
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• pp.235-242
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• 2008

An Autonomous mobile robot is a very useful system to achieve various tasks in dangerous environment, because it has the higher performance than a fixed base manipulator in terms of its operational workspace size as well as efficiency. A method for estimating the position of an object in the Cartesian coordinate system based upon the geometrical relationship between the image captured by 2-DOF active camera mounted on mobile robot and the real object, is proposed. With this position estimation, a method of determining an optimal path for the autonomous mobile robot from the current position to the position of object estimated by the image information using homogeneous matrices. Finally, the corresponding joint parameters to make the desired displacement are calculated to capture the object through the control of a mobile robot. The effectiveness of proposed method is demonstrated by the simulation and real experiments using the autonomous mobile robot.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.25-25
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• 2023

The ensemble optimal interpolation (EnOI) scheme is a sub-optimal alternative to the ensemble Kalman filter (EnKF) with a reduced computational demand making it potentially more suitable for operational applications. Since only one model is integrated forward instead of an ensemble of model realizations, online estimation of the background error covariance matrix is not possible in the EnOI scheme. In this study, we investigate two Gaussian noise based ensemble generation strategies to produce dynamic covariance matrices for assimilation of water level observations into a distributed hydrological model. In the first approach, spatially correlated noise, sampled from a normal distribution with a fixed fractional error parameter (which controls its standard deviation), is added to the model forecast state vector to prepare the ensembles. In the second method, we use an adaptive error estimation technique based on the innovation diagnostics to estimate this error parameter within the assimilation framework. The results from a real and a set of synthetic experiments indicate that the EnOI scheme can provide better results when an optimal EnKF is not identified, but performs worse than the ensemble filter when the true error characteristics are known. Furthermore, while the adaptive approach is able to reduce the sensitivity to the fractional error parameter affecting the first (non-adaptive) approach, results are usually worse at ungauged locations with the former.

• Journal of Korea Society of Industrial Information Systems
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• v.21 no.6
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• pp.109-123
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• 2016

This study investigates the importance of government's support for logistics security assurance through certification programs. First, the study analyzed priorities among the requirements of logistics firms through Analytic Hierarchy Process(AHP) and Quality Function Deployment(QFD) approaches. For this process we invited 21 logistics experts to assess the relationships between logistic firms' requirements and government policies regarding logistics security using the house of quality, a set of matrices of QFD. The results of this phase of the study revealed the priorities of logistics firms' goals regarding the diffusion of the government security certification program as follows: integrated logistics security systems(40.3%), strengthening government support systems(32.4%), and operational effectiveness of logistics security certification(27.2%). Second, a relative weights applied QFD method based on AHP was applied to determined the expected outcome of the logistics security certification program. The results indicated as follows: productivity improvement(28.4%), improved level of service(26.7%), logistics cost reduction(21.6%), advanced information systems(19.7%), and improved environmental protection(3.6%). The results of this study provide new insights concerning logistics firms' requirements for supply chain security and the importance of government's support policies through logistics security certification programs.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.42 no.5 s.305
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• pp.1-12
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• 2005

A Mobile manipulator - a serial connection of a mobile robot and a task robot - is a very useful system to achieve various tasks in dangerous environment. because it has the higher performance than a fixed base manipulator in regard to the size of it's operational workspace. Unfortunately the use of a mobile robot introduces non-holonomic constraints, and the combination of a mobile robot and a manipulator generally introduces kinematic redundancy. In this paper, first a method for estimating the position of object at the cartesian coordinate system acquired by using the geometrical relationship between the image captured by 2-DOF active camera mounted on mobile robot and real object is proposed. Second, we propose a method to determine a optimal path between current the position of mobile manipulator whose mobile robot is non-holonomic and the position of object estimated by image information through the global displacement of the system in a symbolic way, using homogenous matrices. Then, we compute the corresponding joint parameters to make the desired displacement coincide with the computed symbolic displacement and object is captured through the control of a manipulator. The effectiveness of proposed method is demonstrated by the simulation and real experiment using the mobile manipulator.