• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
• /
• 2002.10a
• /
• pp.68-72
• /
• 2002

Localization with array sensors has been applied for not only military but also non-military purposes. The identification of submarines and fish finding are those examples. Nowadays the demand for noise identification is increasing to characterize noise sources and improve acoustic performance of underwater acoustic equipment. For that reason KRISO/KORDI recently constructed an anechoic basin which bus reflection only at the free surface. This paper suggests a noise identification methods using MUSIC algorithm in such an acoustic field. For comparison phase delay sum and minimum valiance methods are also described. At first basic principles are described. A several numerical simulations are also performed. The results say that reflection effect many cause a new non-real source although good estimation is obtained under no reflection conditions.

• Journal of Electrical Engineering and Technology
• /
• v.12 no.3
• /
• pp.1292-1298
• /
• 2017

In this paper, we represent a nonlinear identification of electronic brake pedal behavior in the brake-by-wire (BBW) system based on hybrid group method of data handling (GMDH) and genetic algorithm (GA). A GMDH is a kind of multi-layer network with a structure that is determined through training and which can express nonlinear dynamics as a mathematical model. The GA is used in the GMDH, enabling each neuron to search for its optimal set of connections with the preceding layer. The results obtained with this hybrid approach were compared with different nonlinear system identification methods. The experimental results showed that the hybrid approach performs better than the other methods in terms of root mean square error (RMSE) and correlation coefficients. The hybrid GMDH/GA approach was effective for modeling and predicting the brake pedal system under random braking conditions.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.48 no.6
• /
• pp.789-799
• /
• 1999

In this paper, the optimization of fuzzy inference systems is proposed for fuzzy model of nonlinear systems. A fuzzy model needs to be identified and optimized by means of the definite and systematic methods, because a fuzzy model is primarily acquired by expert's experience. The proposed rule-based fuzzy model implements system structure and parameter identification using the HCM(Hard C-mean) clustering method, genetic algorithms and fuzzy inference method. Two types of inference methods of a fuzzy model are the simplified inference and linear inference. in this paper, nonlinear systems are expressed using the identification of structure such as input variables and the division of fuzzy input subspaces, and the identification of parameters of a fuzzy model. To identify premise parameters of fuzzy model, the genetic algorithms is used and the standard least square method with the gaussian elimination method is utilized for the identification of optimum consequence parameters of fuzzy model. Also, the performance index with weighting factor is proposed to achieve a balance between the performance results of fuzzy model produced for the training and testing data set, and it leads to enhance approximation and predictive performance of fuzzy system. Time series data for gas furnace and sewage treatment process are used to evaluate the performance of the proposed model.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.16 no.3
• /
• pp.528-531
• /
• 2002

In Traditional Oriental Medicine, there has been a growing needs for computerized diagnosis expert system, which can implement pre-diagnosis and correct the errors of practitioners. Therefore, we developed the expert system (KHU-PIPE : Kyung Hee University - Pattern Identification and Prescription Expert) for diagnosis and treatment. It has three characteristics as following. First. this system has the knowledge base which modified the standardized data designed by Chinese government during 1980s. Second, it provides the objective and standardized diagnosis as the results of pattern identification and their appropriate prescriptions for treatment. Third, it is applied to both LAN system and internet. Furthermore, it can be used as an educational methods for the practices of pattern identification and prescription, and provide the objective criteria for clinical studies and promote the Traditional Oriental Medicine as an evidence-based medicine.

• Proceedings of the KIEE Conference
• /
• 2005.10b
• /
• pp.180-182
• /
• 2005

Fingerprint-based identification is known to be used for a very long time. Owing to their uniqueness and immutability, fingerprints are today the most widely used biometric features. Therefore, recognition using fingerprints is one of the safest methods as a way of personal identification. But fingerprint identification system has a critical weakness. Since the fingerprint identification time dramatically increase when we compare the unknown fingerprint's minutiae with fingerprint database's minutiae. In this paper, a ridge orientation extraction method using Index table is proposed to solve the problem. The goal of fast direction image extraction is to reduce the identification time and to improve the clarity of ridge and valley structures of input fingerprint image.

• 한국방재학회:학술대회논문집
• /
• 2007.02a
• /
• pp.45-48
• /
• 2007

The aim of this study is to estimate the compressive force of steel member using a system identification technique with vibration measurements. To date, several methods have been presented to estimate the compressive force using static and/or dynamic responses of the steel member. However, each and every one of these methods has its disadvantages as well as advantages in its procedures, level of accuracy, and equipment requirements. The paper reports a qualitative investigation of vibration under monoharmonic excitation. The methodology utilizes the relationship between the natural frequencies, the structural parameters, and the compressive force of the member. In this paper, experimental results are presented with a steel beam subjecting to several compressive forces and the proposed method is validated using both numerical and experimental data.

• Smart Structures and Systems
• /
• v.4 no.4
• /
• pp.465-492
• /
• 2008

Proper pretest planning is a vital component of any successful vibration test on engineering structures. The most important issue in dynamic testing of many engineering structures is arriving at the number and optimal placement of sensors. The sensors must be placed on the structure in such a way that all the important dynamic behaviour of a structural system is captured during the course of the test with sufficient accuracy so that the information can be effectively utilised for structural parameter identification or health monitoring. Several optimal sensor placement (OSP) techniques are proposed in the literature and each of these methods have been evaluated with respect to a specific problem encountered in various engineering disciplines like aerospace, civil, mechanical engineering, etc. In the present work, we propose to perform a detailed characteristic evaluation of some selective popular OSP techniques with respect to their application to practical civil engineering problems. Numerical experiments carried out in the paper on various practical civil engineering structures indicate that effective independence (EFI) method is more consistent when compared to all other sensor placement techniques.

• Earthquakes and Structures
• /
• v.3 no.3_4
• /
• pp.249-270
• /
• 2012

This paper investigates the effectiveness of widely used identification methods to identify the response of seismically isolated structures supported on bearings with bilinear behavior. The paper shows that while both time domain and frequency domain methods predict with high accuracy the modal characteristics of structures isolated by linear isolation system, their performance degrades appreciably when the isolation system exhibits bilinear behavior even when its strength assumes moderate values (say 5% of the weight). The paper also shows that the natural period of isolated structure that results from bilinear isolation systems can be satisfactorily predicted with wavelet analysis.

• Proceedings of the KIEE Conference
• /
• 2008.04a
• /
• pp.199-200
• /
• 2008

Demand for reliability and safety in modem systems has been increased in the research on fault detection and isolation. At traditional approaches to fault detection, redundant sensors have been used. More advanced methods are the residual analysis of signals which are created by the comparison between the actual plant behavior and the output response of a mathematical model. However, mathematical system models are difficult to obtain by using physical laws. These problems can be solved by system identification. In this paper, the transfer function of a direct current motor is estimated by using the system identification. And, the efficiency of the fault detector design is verified by using experiments.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.61 no.8
• /
• pp.1164-1171
• /
• 2012

Recently, machine olfactory systems as an artificial substitute of the human olfactory system are being studied actively because they can scent dangerous gases and identify the type of gases in contamination areas instead of the human. In this paper, we present an effective design method for the gas identification system. Even though dimensionality reduction is the very important part, in pattern analysis, We handled effectively the dimensionality reduction by grouping the sensors of which the measured patterns are similar each other, where genetic algorithms were used for combination optimization. To identify the gas type, we constructed the hierarchical rule base with two frames by using rough set theory. The first frame is to accept measurement characteristics of each sensor and the other one is to reflect the identification patterns of each group. Thus, the proposed methods was able to accomplish effectively dimensionality reduction as well as accurate gas identification. In simulation, we demonstrated the effectiveness of the proposed methods by identifying five types of gases.