• Proceedings of the Korea Society for Industrial Systems Conference
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• 2002.11a
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• pp.407-411
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• 2002

Ternary sequences are digital codes consisting of discrete values -1, 0, and 1 only. They are advantageous in that the correlation can be carried out using additions only Also, they feature an ideal circular autocorrelation function, but in channel characterization tasks, the usual requirement is that the linear autocorrelation function be ideal, i.e., a Kronecker delta function. In this article, we consider two approaches to improving their linear autocorrelation or crosscorrelation properties: one is an inverse filtering method with theresholding and the other is a singular value decomposition (SVD) method. Both methods are simulated under noisy circumstances. The inverse filtering method resulted in an improvement in peak sidelobe level of about 1㏈ at an SNR of 30㏈, and the SVD method showed similar performances, albeit more sensitive to noise depending on the singular value selection strategy.

• Journal of KIISE:Software and Applications
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• v.36 no.2
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• pp.169-177
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• 2009

In this paper, we propose a new shot boundary detection method which is optimized for news video story parsing. This new news shot boundary detection method was designed to satisfy all the following requirements: 1) minimizing the incorrect data in data set for anchor shot detection by improving the recall ratio 2) detecting abrupt cuts and gradual transitions with one single algorithm so as to divide news video into shots with one scan of data set; 3) classifying shots into static or dynamic, therefore, reducing the search space for the subsequent stage of anchor shot detection. The proposed method, based on singular value decomposition with incremental clustering and mercer kernel, has additional desirable features. Applying singular value decomposition, the noise or trivial variations in the video sequence are removed. Therefore, the separability is improved. Mercer kernel improves the possibility of detection of shots which is not separable in input space by mapping data to high dimensional feature space. The experimental results illustrated the superiority of the proposed method with respect to recall criteria and search space reduction for anchor shot detection.

• Journal of the Korea Concrete Institute
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• v.16 no.4 s.82
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• pp.511-520
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• 2004

The fracture energy evaluated from the previous experimental results can be simulated by using the modified singular fracture process zone (S-FPZ) model. The fracture model has two fracture properties of strain energy release rate for crack extension and crack close stress versus crack width relationship $f_{ccs}$ ( w ) for fracture process zone (FPZ) development. The $f_{ccs}$( w ) relationship is not sensitive to specimen geometry and crack velocity. The fracture energy rate in the FPZ increases linearly with crack extension until the FPZ is fully developed. The fracture criterion of the strain energy release rate depends on specimen geometry and crack velocity as a function of crack extension. The variation of strain energy release rate with crack extension can explain theoretically the micro-cracking, micro-crack localization and full development of the FPZ in concrete.

• Journal of the Korea Convergence Society
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• v.11 no.12
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• pp.23-30
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• 2020

In this study, the relationship between natural gas (NG) data and gas-related environmental elements was performed using machine learning algorithms to predict the level of gas leakage risk without directly measuring gas leakage data. The study was based on open data provided by the server using the IoT-based remote control Picarro gas sensor specification. The naturel gas leaks into the air, it is a big problem for air pollution, environment and the health. The proposed method is multivariate outlier removing method based Random Forest (RF) classification for predicting risk of NG leak. After, unsupervised k-means clustering, the experimental dataset has done imbalanced data. Therefore, we focusing our proposed models can predict medium and high risk so best. In this case, we compared the receiver operating characteristic (ROC) curve, accuracy, area under the ROC curve (AUC), and mean standard error (MSE) for each classification model. As a result of our experiments, the evaluation measurements include accuracy, area under the ROC curve (AUC), and MSE; 99.71%, 99.57%, and 0.0016 for MOL_RF respectively.

• Journal of Food Hygiene and Safety
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• v.38 no.5
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• pp.347-355
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• 2023

In this study, polymerase chain reaction (PCR) and loop-mediated isothermal amplification (LAMP) were compared in terms of their ability to detect shiga-toxin-producing Escherichia coli (STEC). Various foods were artificially inoculated with STEC to evaluate the limit of detection (LOD), limit of quantification (LOQ), sensitivity, specificity, and efficiency of PCR and LAMP. The LODs were ≤10⁴ and ≤10³ CFU/mL for PCR and LAMP, respectively. The LOQs did not differ between PCR and LAMP. However, of the four considered food types, the sensitivities differed by a maximum of 11.1% for seasoned meat and by a minimum of 8.1% for ground beef. LAMP had higher sensitivity than that of PCR and 100% specificity for all four food types. Therefore, LAMP is a reliable molecular method for detecting STEC as comparable to PCR assay, and its specificity and sensitivity are superior to those of PCR, depending on the food type.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.6
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• pp.263-268
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• 2010

As the demand of high quality service in next generation wireless communication systems, a high performance of data transmission requires an increase of spectrum efficiency and an improvement of error performance in wireless communication systems. In this paper, we propose a multi-user multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system with cyclic delay diversity and block diagonalization procoding method to improve bit error rate (BER) performance with wireless local area network (WLAN) channel model C and D for 802.11n WLAN system. The results of mathlab simulation show the improvement of BER performance in 802.11n wireless indoor channel environment.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.2 s.308
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• pp.82-86
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• 2006

The design of a pattern recognition system generally involves the three aspects: preprocessing, feature extraction, and decision making. Among them, a feature extraction method determines an appropriate subspace of dimensionality in the original feature space of dimensionality so that it can reduce the complexity of the system and help to improve successful recognition rates. Linear transforms, such as principal component analysis, factor analysis, and linear discriminant analysis have been widely used in pattern recognition for feature extraction. This paper shows that singular value decomposition (SVD) can be applied usefully in feature extraction stage of pattern recognition. As an application, a remote sensing problem is applied to verify the usefulness of SVD. The experimental result indicates that the feature extraction using SVD can improve the recognition rate about 25% compared with that of PCA.

• Korean Journal of Materials Research
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• v.3 no.4
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• pp.422-423
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• 1993

In this short note, we report the result of measurement for the ferro- to paramagnetic phase transition temperature, that is Curie point of bulk gadolinium. This note is written to give the solid validity for the previous measurement of Curie point shift of gadolinium film (1. Rhee, E. Lee and S. Lee, Kor. J. of Mat. Research,3, 3, 1993). The Curie point of bulk gadolinium is determined by measuring the resistance of sample as function of temperatures. At Curie point, we can observe the resistivity anomaly which arises due to the heat capacity difference between below and above Curie point. Finally, the curie point of bulk gadolinium is found to be 19.2${\pm}$0.$3^{\circ}C$.

• Journal of Institute of Control, Robotics and Systems
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• v.2 no.1
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• pp.35-44
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• 1996

A design method for a teleoperator robot system is presented in this paper. The control system consists of two phases; approach phase and contact one. The end-effector position of the estimated slave robot and the contact force between the end-effector and wall are displayed on the monitors at control site, using which the operator controls the teleoperator system. The approach phase controller is designed using Smith's principle and the contact one designed based upon the structured singular value ${\mu}$ in order to increase the robustness of the system. The uncertainatices such as communication time delay and the variations of system parameters are considered as a muliplicative pertubation. Computer simulations are conducted in order to evaluate the performance of the proposed design method. It is found that desirable control performance, especially in the contact phase, is obtained if the control mode is switched into contact phase when the estimated position of the slave robot end-effector is in front of the wall.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.2
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• pp.338-344
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• 2017

In this paper, two-way amplify-and-forward relay methods are investigated where two terminals and one relay node are equipped with multiple antennas. In two-way relay channels, it is assumed that one terminal can eliminate its own self-interference but the other cannot. For this channel, we first maximize the sum-rate performance by employing an iterative gradient descent (GD) algorithm. Then, a simple singular value decomposition (SVD) based block triangularization is developed to null the self-interference. Simulation results show the proposed methods outperform the conventional schemes for various environments.