• Proceedings of the Korean Information Science Society Conference
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• 2004.04b
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• pp.568-570
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• 2004

The error-backpropagation (EBP) algerithm for training multilayer perceptrons (MLPs) is known to have good features of robustness and economical efficiency. However, the algorithm has difficulty in selecting an optimal constant learning rate and thus results in non-optimal learning speed and inflexible operation for working data. This paper Introduces an elastic learning rate that guarantees convergence of learning and its local realization by online upoate of MLP parameters Into the original EBP algorithm in order to complement the non-optimality. The results of experiments on a speaker verification system with Korean speech database are presented and discussed to demonstrate the performance improvement of the proposed method in terms of learning speed and flexibility fer working data of the original EBP algorithm.

• Proceedings of the Korean Society of Computer Information Conference
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• 2021.07a
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• pp.563-564
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• 2021

반려동물 보유 가구 수가 증가하면서 반려동물의 상실로 인한 펫로스 증후군을 호소하는 반려인 또한 증가하고 있다. 펫로스 증후군을 치유하기 위해 반려동물을 가상으로라도 만나서 평소에 하던 말과 행동을 할 수 있도록 하여 차츰 이별을 할 수 있도록 할 필요가 있다. 본 논문에서는 VR을 통하여 반려인이 3D로 모델링 된 반려동물과 직접 교감할 수 있는 시스템에 대한 연구 내용을 기술한다. 이 시스템을 통해 떠나보낸 반려동물과 평소와 같은 말과 행동을 할 수 있도록 도와주어 감정의 정화를 서서히 할 수 있도록 해준다.

• Journal of KIISE:Computing Practices and Letters
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• v.8 no.3
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• pp.344-355
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• 2002

Having a variety of good characteristics against other pattern recognition techniques, Multilayer Perceptron (MLP) has been used in wide applications. But, it is known that Error Backpropagation (EBP) algorithm which MLP uses in learning has a defect that requires relatively long leaning time. Because learning data in pattern recognition contain abundant redundancies, in order to increase learning speed it is very effective to use online-based teaming methods, which update parameters of MLP pattern by pattern. Typical online EBP algorithm applies fixed learning rate for each update of parameters. Though a large amount of speedup with online EBP can be obtained by choosing an appropriate fixed rate, fixing the rate leads to the problem that the algorithm cannot respond effectively to different leaning phases as the phases change and the learning pattern areas vary. To solve this problem, this paper defines learning as three phases and proposes a Instant Learning by Varying Rate and Skipping (ILVRS) method to reflect only necessary patterns when learning phases change. The basic concept of ILVRS is as follows. To discriminate and use necessary patterns which change as learning proceeds, (1) ILVRS uses a variable learning rate which is an error calculated from each pattern and is suppressed within a proper range, and (2) ILVRS bypasses unnecessary patterns in loaming phases. In this paper, an experimentation is conducted for speaker verification as an application of pattern recognition, and the results are presented to verify the performance of ILVRS.

• Journal of the Korean Society of Industry Convergence
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• v.20 no.4
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• pp.285-297
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• 2017

This study proposed a new approach to develop an Intelligent control algorithm for cooperative working of human and robot based on voice recognition. In general case of speaker verification, Gaussian Mixture Model is used to model the feature vectors of reference speech signals. On the other hand, Dynamic Time Warping based template matching techniques were presented for the voice recognition about several years ago. We converge these two different concepts in a single method and then implement in a real time voice recognition enough to make reference model to satisfy 95% of recognition performance. In this paper it was illustrated the reliability of voice recognition by simulation and experiments for humanoid robot with 18 joints.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.131-134
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• 2004

본 논문에서는 GMM(Gaussian Mixture Model)을 이용한 문맥독립 화자 검증 시스템을 구현한 후, arctan 함수를 이용한 정규화 방법을 사용하여 화자검증실험을 수행하였다. 특징파라미터로서는 선형예측방법을 이용한 켑스트럼 계수와 회귀계수를 사용하고 화자의 발성 변이를 고려하여 CMN(Cepstral Mean Normalization)을 적용하였다. 화자모델 생성을 위한 학습단에서는 화자발성의 음향학적 특징을 잘 표현할 수 있는 GMM(Gaussian Mixture Model)을 이용하였고 화자 검증단에서는 ML(Maximum Likelihood)을 이용하여 유사도를 계산하고 기존의 정규화 방법과 arctan 함수를 이용한 방법에 의해 정규화된 점수(score)와 미리 정해진 문턱값과 비교하여 검증하였다. 화자 검증 실험결과, arctan 함수를 부가한 방법이 기존의 방법보다 항상 향상된 EER을 나타냄을 확인할 수 있었다.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.5
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• pp.437-446
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• 2016

Feature selection has become an essential technique to reduce the dimensionality of data sets. Many features are frequently irrelevant or redundant for the classification tasks. The purpose of feature selection is to select relevant features and remove irrelevant and redundant features. Applications of the feature selection range from text processing, face recognition, bioinformatics, speaker verification, and medical diagnosis to financial domains. In this study, we focus on filter methods based on information entropy : IG (Information Gain), FCBF (Fast Correlation Based Filter), and mRMR (minimum Redundancy Maximum Relevance). FCBF has the advantage of reducing computational burden by eliminating the redundant features that satisfy the condition of approximate Markov blanket. However, FCBF considers only the relevance between the feature and the class in order to select the best features, thus failing to take into consideration the interaction between features. In this paper, we propose an improved FCBF to overcome this shortcoming. We also perform a comparative study to evaluate the performance of the proposed method.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.25 no.2
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• pp.85-92
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• 2022

The amphibian breeding habitat is confirmed by mating call. In some cases, the researcher directly identifies the amphibian individual, but in order to designate the habitat, it is necessary to map the mating call region of the amphibian population. Until now, it has been a popular methodology for researchers to hear mating calls and outline their breeding habitats. To improve this subjective methodology, we developed a technique for mapping mating call regions using Unmanned Aerial Vehicle (UAV). The technology uses a UAV, fitted with a sound recorder to record ground mating calls as it flies over an amphibian habitat. The core technology is to synchronize the recorded sound pressure with the flight log of the UAV and predict the sound pressure in a two-dimensional plane with probability density. For a demonstration study of this technology, artificial mating call was generated by a potable speaker on the ground and recorded by a UAV. Then, the recorded sound data was processed with an algorithm developed by us to map mating calls. As a result of the study, the correlation coefficient between the artificial mating call on the ground and the mating call map measured by the UAV was R=0.77. This correlation coefficient proves that our UAV recording system is sufficiently capable of detecting amphibian mating call regions.

• Journal of Korea Society of Digital Industry and Information Management
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• v.19 no.1
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• pp.119-127
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• 2023

Recently, deep learning has been used in the development of various institutional devices and services to help the visually impaired people in their daily lives. This is because not only are there few products and facility guides written in braille, but less than 10% of the visually impaired can use braille. In this paper, we propose a system that recognizes beverage cans in real time and outputs the beverage can name with sound for the convenience of the visually impaired. Five commercially available beverage cans were selected, and a CNN model and a YOLO model were designed to recognize the beverage cans. After augmenting the image data, model training was performed. The accuracy of the proposed CNN model and YOLO model is 91.2% and 90.8%, respectively. For practical verification, a system was built by attaching a camera and speaker to a Raspberry Pi. In the system, the YOLO model was applied. It was confirmed that beverage cans were recognized and output as sound in real time in various environments.

• Culinary science and hospitality research
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• v.19 no.3
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• pp.57-72
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• 2013

This study carried out an empirical analysis on the long-term effects of a marketing communication strategy used as a means of promotion(advertisement, free gift) of Christmas cake despite its high costs. Such verification results were considered to provide as important core elements for successful management in the bakery industry. By utilizing SPSS and AMOS, exploratory factor analysis(EFA) and confirmatory factor analysis(CFA) were conducted for the validity of the measurement items, and Structural Equation Model(SEM) was performed to verify the hypothesis. The analysis result is as follows. First, advertisement attribute(${\beta}$=0.269, t=4.512, p,<0.001) and free gift attitude(${\beta}$=0.293, t=5.043, p<0.001) had a positive influence on trust. Second, trust had a positive influence on purchase intention(${\beta}$=0.513, t=8.677, p<0.001). Third, advertisement attribute(${\beta}$=0.104, t=1.966, p,<0.05) and free gift attitude(${\beta}$=0.204, t=3.817, p<0.001) had a positive influence on purchase intention. Lastly, advertisement attitude appeared different by advertisement types(actors and animation), and ads with an actor were evaluated high than animation ads. Also, gift attitude appeared different by gift types(speaker doll/character hat and turtleneck muffler), and a turtleneck muffler was evaluated high than a speaker doll or a character hat.

• Journal of Digital Convergence
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• v.10 no.5
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• pp.215-222
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• 2012

A smart phone has functions of both telephone and computer. The wide spread use of smart phones has sharply increased the demand for mobile commerce. The smart phone based mobile services are available anytime, anywhere. In commercial transactions, a digital signature scheme is used to make legally binding signature to prove both integrity of commercial document and verification of the signer. Smart phones are more risky compared with personal computers on the problems of how to protect privacy information. It's also easy to let proxy user to authenticate instead of the smart phone owner. In existing password or token based schemes, the ID is not physically bound to the owner. Thus, those schemes can not solve the problem of proxy authentication. To utilize the smart phone as the platform of mobile commerce, a study on the new type of authentication scheme is needed where the scheme should provide protocol to get legally binding signature and not to authenticate proxy user. In this paper, we create the mobile ID by using both the USIM and voice template of the smart phone owner. We also design and implement the user authentication scheme based on the mobile ID.