• Journal of Power Electronics
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• v.8 no.3
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• pp.228-238
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• 2008

Many induction motor broken bar diagnosis methods are based on evaluating special components in machine signals spectrums. Current, power, flux, etc are among these signals. Frequencies related to a broken rotor fault are slip dependent, therefore, correct diagnosis of fault - especially when obtrusive frequency components are present - depends on accurate determination of motor velocity and slip. The traditional methods typically require several sensors that should be pre-installed in some cases. This paper presents a diagnosis method based on only a vibration sensor. Motor velocity oscillation due to a broken rotor causes frequency components at twice slip frequency difference around speed frequency in vibration spectrum. Speed frequency and its harmonics as well as twice supply frequency, can easily and accurately be found in a vibration spectrum, therefore th motor slip can be computed. Now components related to rotor fault can be found. It is shown that a trained neural network - as a substitute for an expert person - can easily categorize the existence and the severity of a fault according to the features extracted from the presented method. This method requires no information about th motor internal and has been able to diagnose correctly in all the laboratory tests.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.4
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• pp.194-199
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• 2017

Power transformers are an important factor for power transmission and cause fatal losses if faults occur. Various diagnostic methods have been applied to predict the failure and to identify the cause of the failure. Typical diagnostic methods include the IEC diagnostic method, the Duval diagnostic method, the Rogers diagnostic method, and the Doernenburg diagnostic method using the ratio of the main gas. However, each diagnostic method has a disadvantage in that it can't diagnose the state of the power transformer unless the gas ratio is within the defined range. In order to solve these problems, we propose a diagnosis method using ELM based intelligent algorithm and fuzzy membership function. The final diagnosis is performed by multiplying the result of diagnosis in the four diagnostic methods (IEC, Duval, Rogers, and Doernenburg) by the fuzzy membership values. To show its effectiveness, the proposed fault diagnostic system has been intensively tested with the dissolved gases acquired from various power transformers.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.2_2
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• pp.163-171
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• 2020

The condition of tire tread is a key parameter closely related to the driving safety of a vehicle, which affects the contact force of the tire for braking, accelerating and cornering. The major factor influencing the contact force is tread wear, and the more tire tread wears out, the higher risk of losing control of a vehicle exits. The tire tread condition is generally checked by visual inspection that can be easily forgotten. In this paper, we propose the intelligent tire (iTire) system that consists of an acceleration sensor, a wireless signal transmission unit and a tread classifier. In addition, we also presents classification algorithm that transforms the acceleration signal into the frequency domain and extracts the features of several frequency bands as inputs to an artificial neural network. The artificial neural network for classifying tire wear was designed with an Multiple Layer Perceptron (MLP) model. Experiments showed that tread wear classification accuracy was over 80%.

• Journal of Information Processing Systems
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• v.5 no.2
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• pp.69-76
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• 2009

Self healing systems are considered as cognation-enabled sub form of fault tolerance system. But our experiments that we report in this paper show that self healing systems can be used for performance optimization, configuration management, access control management and bunch of other functions. The exponential complexity that results from interaction between autonomic systems and users (software and human users) has hindered the deployment and user of intelligent systems for a while now. We show that if that exceptional complexity is converted into self-growing knowledge (policies in our case), can make up for initial development cost of building an intelligent system. In this paper, we report the application of AHSEN (Autonomic Healing-based Self management Engine) to in OKKAM Project infrastructure backbone cluster that mimics the web service based architecture of u-Zone gateway infrastructure. The 'blind' load division on per-request bases is not optimal for distributed and performance hungry infrastructure such as OKKAM. The approach adopted assesses the active threads on the virtual machine and does resource estimates for active processes. The availability of a certain server is represented through worker modules at load server. Our simulation results on the OKKAM infrastructure show that the self healing significantly improves the performance and clearly demarcates the logical ambiguities in contemporary designs of self healing infrastructures proposed for large scale computing infrastructures.

• ETRI Journal
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• v.35 no.6
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• pp.1038-1047
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• 2013

Augmented reality (AR) is currently being applied actively to commercial products, and various types of intelligent AR systems combining both the Global Positioning System and computer-vision technologies are being developed and commercialized. This paper suggests an in-vehicle head-up display (HUD) system that is combined with AR technology. The proposed system recognizes driving-safety information and offers it to the driver. Unlike existing HUD systems, the system displays information registered to the driver's view and is developed for the robust recognition of obstacles under bad weather conditions. The system is composed of four modules: a ground obstacle detection module, an object decision module, an object recognition module, and a display module. The recognition ratio of the driving-safety information obtained by the proposed AR-HUD system is about 73%, and the system has a recognition speed of about 15 fps for both vehicles and pedestrians.

• Transactions on Control, Automation and Systems Engineering
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• v.3 no.2
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• pp.117-123
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• 2001

To improve control performance of a non-linear system, many other reserches have used the sliding model control algorithm. The sliding mode controller is known to be robust against nonlinear and unmodeled dynamic terms. However, this algorithm raises the inherent chattering caused by excessive switching inputs around the sliding surface. Therefore, in order to solve the chattering problem and improve control performance, this study has developed the sliding mode controller with a perturbation estimator using the observer-based fuzzy adaptive network. The perturbation estimator based on the fuzzy adaptive network generates the control input of compensating unmodeled dynamics terms and disturbance. And the weighting parameters of the fuzzy adaptive network are updated on-line by adaptive law in order to force the estimation errors converge to zero. Therefore, the combination of sliding mode control and fuzzy adaptive network gives rise to the robust and intelligent routine. For evaluation control performance of the proposed approach, tracking control simulation is carried is carried out for the hydraulic motion simulator which is a 6-degree of freedom parallel manipulator.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.3
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• pp.67-72
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• 2010

This paper presents biometrical driver verification system in car experiment through analysis of speech, and face information. We have used Mel-scale Frequency Cesptral Coefficients (MFCCs) for speaker verification using speech information. For face verification, face region is detected by AdaBoost algorithm and dimension-reduced feature vector is extracted by using principal component analysis only from face region. In this paper, we apply the extracted speech- and face feature vectors to an SVM kernel with Gaussian Mixture Models(GMM) supervector. The experimental results of the proposed approach show a clear improvement compared to a simple GMM or SVM approach.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2006.05a
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• pp.317-321
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• 2006

게임의 재미요소를 증대 시키고, 게임 생명주기(Life-Cycle)를 늘어나게 하기 위해 다양한 방법이 연구 중이다. 현실감 있는 그래픽 효과와 뛰어난 음향 효과 등과 함께 게임 플레이어의 게임 스타일이 반영된 게임을 만들기 위한 방법이 대표적이 예라 할 수 있다. 그 중 게임 플레이어의 스타일을 게임에 다시 이용하기 위해서는 플레이어의 인지과정이 요구되며, 인지된 결과를 이용하여 플레이어를 모델링(User Modeling)한다. 하지만, 게임의 종류와 특성에 따라 다양한 게임이 존재하기 때문에 플레이어를 모델링하기 어렵다는 문제를 가지고 있다. 본 논문에서는 게임에서 정의된 FSM(Finite State machine)을 이용하여 플레이어가 선택한 행동 패턴을 분석하고 적용하는 방법과 다양한 게임에서 이용 할 수 있는 스크립트 형태의 NPC 행동 패턴 변경 방법을 제안한다. 플레이어의 데이터를 분석하여 얻은 결과는 FSM을 변경하여 새로운 행동을 보이는 NPC(Non-Player Characters)를 생성하는데 사용되며, 이 캐릭터는 게임의 특성과 플레이어의 최신 행동 패턴 경향을 학습한 적용형 NPC라 할 수 있다. 실험을 통하여 사용자의 행동과 유사한 패턴을 보이는 NPC의 생성을 확인할 수 있었으며, 게임에서 상대적인 또는 적대적인 캐릭터로 유용하게 사용 될 수 있다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2006.05a
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• pp.41-44
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• 2006

산업용 로봇으로부터 시작된 로봇에 관한 연구는 서비스 로봇에 대한 개념이 확산되면서 최근 폭발적으로 그 영역을 넓혀가고 있다. 또한, 인간과 함께 생활하는 서비스 로봇의 경우 로봇 스스로가 인간 및 환경을 이해하고 조작할 수 있어야 하므로 매우 높은 수준의 지능이 요구되고 있다. 이에 본 논문에서는 로봇의 지능이란 무엇인가라는 근본적인 문제에 대해 공학적인 측면에서 다루고자 한다. 구체적으로 기존의 개발된 로봇들을 통해 로봇의 지능을 구성하는 요소들을 분석해내고 이를 활용해 특정 로봇의 지능 수준을 측정하거나 또는 서로 다른 두 로봇 간의 지능들을 비교할 수 있는 척도에 대해 제시하고자 한다. 기존의 퍼지 적분 기반 기계 지능 측정법에서의 방법, 즉 Choquet 퍼지 적분과 Sugeno 퍼지 적분을 함께 사용함으로써 정량적/정성적인 판단을 동시에 진행하는 방법을 응용함으로써 인간의 IQ에 해당되는 로봇의 IQ 수치를 얻어낼 수 있게 된다.

• Journal of the Korean Institute of Intelligent Systems
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• v.13 no.2
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• pp.237-242
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• 2003

In this paper, we propose a new adaptive intrusion detection algorithm based on clustering: Kernel-ART, which is composed of the on-line clustering algorithm, ART (adaptive resonance theory), combining with mercer-kernel and concept vector. Kernel-ART is not only satisfying all desirable characteristics in the context of clustering-based IDS but also alleviating drawbacks associated with the supervised learning IDS. It is able to detect various types of intrusions in real-time by means of generating clusters incrementally.