• Journal of Electrical Engineering and Technology
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• 제10권4호
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• pp.1877-1885
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• 2015

This paper presents a new Nearest-Neighbors based weighted representation for images and weighted K-Nearest-Neighbors (WKNN) classifier to improve the precision of image classification using the Bag of Visual Words (BOVW) based models. Scale-invariant feature transform (SIFT) features are firstly extracted from images. Then, the K-means++ algorithm is adopted in place of the conventional K-means algorithm to generate a more effective visual dictionary. Furthermore, the histogram of visual words becomes more expressive by utilizing the proposed weighted vector quantization (WVQ). Finally, WKNN classifier is applied to enhance the properties of the classification task between images in which similar levels of background noise are present. Average precision and absolute change degree are calculated to assess the classification performance and the stability of K-means++ algorithm, respectively. Experimental results on three diverse datasets: Caltech-101, Caltech-256 and PASCAL VOC 2011 show that the proposed WVQ method and WKNN method further improve the performance of classification.

• 대한기계학회논문집
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• 제17권6호
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• pp.1330-1341
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• 1993

본 연구에서는 회전대우(revolute joint)들로 이루어진 1자유도 평면기구들의 특성을 파악하고 그래이프이론(graph theory)을 이용하여 기구의 형태를 행렬로 표시 하여 체이터베이스에 저장하였다. 또한 기구의 특성중의 하나인 작업조건(function specification)에 따른 무오차점(precision point)의 최대 개수를 알아내는 프로그램 을 개발하여 이로써 얻은 정보를 또 다른 데이타베이스에 저장하였다. 이와같이 구축 된 데이터베이스들로부터 설계자의 요구에 적합한 기구를 선택하여 형태합성 문제를 해결하였다.

• 대한기계학회논문집
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• 제18권1호
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• pp.1-11
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• 1994

This paper presents an intelligent robotic control method for chamferless parts mating by integrating fuzzy control and neural network. The successful assembly task requires an extremely high position accuracy and a good knowledge of mating parts. However, conventional assembly method alone makes it difficult to achieve satisfactory assembly performance because of the complexity and the uncertainties of the process and its environments such as not only the limitation of the devices performing the assembly but also imperfect knowledge of the parts being assembled. To cope with these problems, an intelligent robotic assembly method is proposed, which is composed of fuzzy controller and learning mechanism based upon neural net. In this method, fuzzy controller copes with the complexity and the uncertainties of the assembly process, while neural network enhances the assembly scheme so as to learn fuzzy rules from experience and adapt to changes in environment of uncertainty and imprecision. The performance of the proposed assembly scheme is evaluted through a series of experiments using SCARA robot. The results show that the proposed control method can be effectively applied to chamferless precision parts mating.

• The Journal of the Acoustical Society of Korea
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• 제15권4E호
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• pp.28-36
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• 1996

In this paper, we propose a new evaluation methodology which can more clearly show the performance of the allophone modeling algorithm generally used in large vocabulary speech recognition. The proposed evaluation method shows the running characteristics and limitations of the modeling algorithm by testing how the variation of phonetic environments of training data affects the recognition performance and the desirable number of free parameters to be estimated. Using the method, we experiment results, we conclude that, in vocabulary-independent recognition task, the phonetic diversity of training data greatly affects the robustness of model, and it is necessary to develop a proper measure which can determine the number of states compromizing the robustness and the precision of the HMnet better than the conventional modeling efficiency.

• 전자공학회논문지
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• 제51권5호
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• pp.168-176
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• 2014

영상 시퀀스로부터 움직이는 객체의 검출은 비디오 감시, 교통 모니터링 및 분석, 사람 검출 및 추적 등에서 가장 기본적이며 중요한 분야이다. 안개와 같은 환경적 요인에 의하여 화질이 저하된 영상 속에서 움직이는 객체를 검출하는 일은 매우 어렵다. 특히, 안개는 주변 물체의 색상을 모두 비슷하게 만들고 채도를 떨어뜨려 배경으로부터 객체를 구별하기 힘들게 만든다. 이런 이유로 안개 영상 속에서 객체 검출 성능은 매우 낮으며 신뢰할 수 없는 결과를 나타내고 있다. 본 논문은 안개와 같은 환경적 요인을 제거하고 객체의 검출 성능을 높이기 위한 방법으로 안개 지수를 기반으로 안개 유무를 판단하고, Dark Channel Prior을 이용하여 안개 영상의 전달량을 추정하고 안개가 제거된 영상으로 복원하였으며 가우시안 혼합 모델을 이용한 배경 차분 방법을 이용하여 객체를 검출하였다. 그리고 제안된 방법의 성능을 비교하기 위해 안개 제거 전과 후의 영상에 대한 Recall 과 Precision을 측정하여 안개 제거에 따른 성능 향상 정도를 수치화하여 비교하였다. 결과적으로 안개 제거 후 영상의 가시성이 매우 향상되었으며 객체 검출 성능이 매우 향상됨을 알 수 있었다.

• 한국정밀공학회지
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• 제27권12호
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• pp.92-98
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• 2010

The design of press bonding tool in LCD module equipment is a very complex and difficult task because many design able variables are involved while their effects are not known. It takes longtime experiments and much expenses to verify the effects of these design variables. However the optimization of bonding tool using OLB(outer lead bonding) and PCB Bonding is a very important problem in LCD manufacturing process, so much design efforts have been made for improving the bonding tool performance. In this paper, a reasonable and fast process which gives optimized solution under the design requirements has been presented. Both analytical and statistical methods are employed in this process. A reliable analytic model using experiment-oriented FE analysis can be obtained, in which the regression equations that predict the tool efficiency from various DOE method are found. Improvement of tool efficiency could be estimated by the regression equations using meaningful factors converged by RSM(Response Surface Method). With this process a reasonable optimized solution that meets a variety of design requirements can be easily obtained.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.2
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• pp.311-315
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• 2006

Precision location and positioning of Asset within a network is an attractive feature with various applications, especially in indoor environments. Such a demand is met by the standard task group, IEEE 802.15.4a. Several methods, that is, pulse, chirp and chaotic communications have been proposed so far to satisfy the requirements of the standard. Among them, ultra wideband direct chaotic communications has advantageous features such as low hardware complexity, low cost, lower power consumption and flexible frequency band plan. In this paper, the feasibility of the ranging system using non-coherent chaotic transceiver is investigated by designing and implementing the system and the performance is proved by conducting location experiments in real indoor environments.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권5호
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• pp.1963-1978
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• 2015

With the advancement of mobile web environments, identification and analysis of the user behavior play a significant role and remains a challenging task to implement with variations observed in the model. This paper presents an efficient method for mining optimized user behavior prediction model using genetic algorithm on mobile web structure. The framework of optimized user behavior prediction model integrates the temporary and permanent register information and is stored immediately in the form of integrated logs which have higher precision and minimize the time for determining user behavior. Then by applying the temporal characteristics, suitable time interval table is obtained by segmenting the logs. The suitable time interval table that split the huge data logs is obtained using genetic algorithm. Existing cluster based temporal mobile sequential arrangement provide efficiency without bringing down the accuracy but compromise precision during the prediction of user behavior. To efficiently discover the mobile users' behavior, prediction model is associated with region and requested services, a method called optimized user behavior Prediction Model using Genetic Algorithm (PM-GA) on mobile web structure is introduced. This paper also provides a technique called MAA during the increase in the number of models related to the region and requested services are observed. Based on our analysis, we content that PM-GA provides improved performance in terms of precision, number of mobile models generated, execution time and increasing the prediction accuracy. Experiments are conducted with different parameter on real dataset in mobile web environment. Analytical and empirical result offers an efficient and effective mining and prediction of user behavior prediction model on mobile web structure.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제14권2호
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• pp.136-144
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• 2014

The existing conventional motion controller does not perform well in the presence of nonlinear properties, uncertain factors, and servo lag phenomena of industrial actuators. Hence, a feasible and effective fuzzy self-tuning proportional integral derivative (PID) and feed-forward control scheme is introduced to overcome these problems. In this design, a fuzzy tuner is used to tune the PID parameters resulting in the rejection of the disturbance, which achieves better performance. Then, both velocity and acceleration feed-forward units are added to considerably reduce the tracking error due to servo lag. To verify the capability and effectiveness of the proposed control scheme, the hardware configuration includes digital signal processing (DSP) which plays the main role, dual-port RAM (DPRAM) to guarantee rapid and reliable communication with the host, field-programmable gate array (FPGA) to handle the task of the address decoder and receive the feed-back encoder signal, and several peripheral logic circuits. The results from the experiments show that the proposed motion controller has a smooth profile, with high tracking precision and real-time performance, which are applicable in various manufacturing fields.

• 한국표면공학회지
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• 제39권2호
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• pp.64-69
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• 2006

Nanoscale task such as nanolithography and nanoindenting is a challenging work that is beyond the capabilities of human sensing and precision. Since surface forces and intermolecular forces dominate over gravitational and other more intuitive forces of the macro world at the nanoscale, a user is not familiar with these novel nanoforce effects. In order to overcome this scaling barrier, haptic interfaces that consist of visual and force feedback at the macro world have been used with an Atomic Force Microscope (AFM) as a manipulator at the nanoscale. In this paper, a nanoscale virtual coupling (NSVC) concept is introduced and the relationship between performance and impedance scaling factors of velocity (or position) and force are explicitly represented. Experiments have been performed for nanoindenting and nanolithography with different materials in the nanoscale virtual surface. The interaction forces (non contact and contact nanoforces) between the AFM tip and the nano sample are transmitted to the operator through the haptic interface.