• The KIPS Transactions:PartD
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• v.10D no.1
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• pp.23-32
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• 2003

Since the data is collected from disparate sources in many actual data mining environments, it is common to have data values in different abstraction levels. This paper shows that such multiple abstraction levels of data can cause undesirable effects in decision tree classification. After explaining that equalizing abstraction levels by force cannot provide satisfactory solutions of this problem, it presents a method to utilize the data as it is. The proposed method accommodates the generalization/specialization relationship between data values in both of the construction and the class assignment phase of decision tree classification. The experimental results show that the proposed method reduces classification error rates significantly when multiple abstraction levels of data are involved.

• Journal of KIISE:Databases
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• v.41 no.4
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• pp.256-261
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• 2014

The problem of top-${\kappa}$ set similarity joins finds the top-${\kappa}$ pairs of records ranked by their similarities between two sets of input records. We propose an efficient algorithm to return top-${\kappa}$ similarity join pairs using a sampling technique. From a sample of the input records, we construct a histogram of set similarity joins, and then compute an estimated similarity threshold in the histogram for top-${\kappa}$ join pairs within the error bound of 95% confidence level based on statistical inference. Finally, the estimated threshold is applied to the traditional similarity join algorithm which uses the min-heap structure to get top-${\kappa}$ similarity joins. The experimental results show the good performance of the proposed algorithm on large real datasets.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.10
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• pp.1007-1014
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• 2004

This paper presents a study of low frequencies volume velocity vibration control of a smart panel in order to reduce sound transmission. A distributed piezoelectric quadratically shaped polyvinylidene fluoride (PVDF) polymer film is used as a uniform force actuator and an array of $4\;{\times}\;4$ accelerometer is used as a volume velocity sensor for the implementation of a single-input single-output control system. The theoretical and experimental study of sensor-.actuator frequency response function shows that this sensor-actuator arrangement provides a required strictly positive real frequency response function below about 900 Hz. Direct velocity feedback could therefore be implemented with a limited gain which gives reductions of about 15 dB in vibration level and about 8 dB in acoustic power level at the (1,1) mode of the smart panel. It has been also shown that the shaping error of PVDF actuator could limit the stability and performance of the control system.

• Journal of the Korean Statistical Society
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• v.33 no.4
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• pp.411-433
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• 2004

The shrinkage preliminary test ridge regression estimators (SPTRRE) based on Wald (W), Likelihood Ratio (LR) and Lagrangian Multiplier (LM) tests for estimating the regression parameters of the multiple linear regression model with multivariate Student's t error distribution are considered in this paper. The quadratic biases and risks of the proposed estimators are compared under both null and alternative hypotheses. It is observed that there is conflict among the three estimators with respect to their risks because of certain inequalities that exist among the test statistics. In the neighborhood of the restriction, the SPTRRE based on LM test has the smallest risk followed by the estimators based on LR and W tests. However, the SPTRRE based on W test performs the best followed by the LR and LM based estimators when the parameters move away from the subspace of the restrictions. Some tables for the maximum and minimum guaranteed efficiency of the proposed estimators have been given, which allow us to determine the optimum level of significance corresponding to the optimum estimator among proposed estimators. It is evident that in the choice of the smallest significance level to yield the best estimator the SPTRRE based on Wald test dominates the other two estimators.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2001.06a
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• pp.17-20
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• 2001

In this paper, we realized a transceiver system for short distance communication with a commercial RF module working in ISM band. Also we measured system performance by transmitting baseband data in a building and then we compared the demodulated data bits with stored data bits in a PC connected with demodulator. The RF module In the experiments works only in the bandwidth of 424MHz-429MHz. The signal level degrades as the distance between transmitter and receiver increases. We measured the signal level and bit error and present the measured results with various locations in the building. And it is concluded that the measured data may be used in the design of short distance network in a building.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.6
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• pp.689-694
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• 2014

An SPLC (Safety Programmable Logic Controller) must be designed to meet the highest safety standards, IEEE 1E, and should guarantee a level of fault-tolerance and high-reliability that ensures complete error-free operation. In order to satisfy these criteria, I/O modules, communication modules, processor modules and bus modules of the SPLC have been configured in triple or dual modular redundancy. The redundant modules receive the same data to determine the final data by the voting logic. Currently, the processor of each rx module performs the voting by deciding on the final data. It is the intent of this paper to prove the improvement on the current system, and develop a voting system for multiple data on a system bus level. The new system bus protocol is implemented based on a TCN-MVB that is a deterministic network consisting of a master-slave structure. The test result shows that the suggested system is better than the present system in view of its high utilization and improved performance of data exchange and voting.

• The Korea Journal of Herbology
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• v.25 no.1
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• pp.45-54
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• 2010

Objectives : The purpose of this study is to determine the impurity tolerance of Zanthoxylum Peel. Methods : Compare with medicinal Herb Books and the Pharmacopoeia of 6 nations. Results : Current Pharmacopoeia show different Zanthoxylum Peel's Purity, such as 2.0% of seeds and fruit stalk, etc. in North Korea, 2% of seeds in Vietnam, totally 3% in China. On the other hand, Korea and Japan set the total number 26.0% including the specific numbers such as 20.0% of seeds, 5.0% of fruit stalk, 1.0% of the other foreign matter. This Zanthoxylum Peel's Purity, 26.0%, is too high compared to that of other medical matters specified by The Korean Pharmacopoeia Ninth Edition. When The Japanese Pharmacopoeia Sixth Edition firstly set the Zanthoxylum Peel's Purity, the herbal name was Fructus. However, since the part for medical usage in origin is well-ripen pericarp, not seed, the permissible level, 30.0%, is supposed to be simple error range, 3.0%. Conclusions : As a result, I think bills concerning the Zanthoxylum Peel's Purity should be revised to the total number 3.0% or specifically set the level 2.0% of seeds, 1.0% of fruit stalk, twig and so on.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.9
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• pp.66-72
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• 2005

As one of the methods that determine position using GPS carrier phase without the resolution of integer ambiguity, the characteristics of the time difference is analyzed in this paper. When determining position by the needed accuracy, the difference time gap becomes an important factor. It is said that accuracy is improved as the difference time gap is getting large, and finally the centimeter level accuracy is achieved after a certain difference time gap. In this paper, the characteristics of the time difference is analyzed using real data and a new parameter is proposed to predict the resulting position accuracy. The difference time gap when position error is converged to the centimeter level is estimated with the proposed parameter.

• Journal of Sasang Constitutional Medicine
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• v.15 no.1
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• pp.109-117
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• 2003

There have been several the reports that the mechanism of Sasang consititution might be understood in the level of genes. Previous study of the authors showed that HLA types and constitutional information had significant relationships. One hundred subjects who showed Taeum characteristics were selected in the present study. HLA-A, HLA-B, HLA-DRB1, ACE, ${\beta}-IIAR$, ${\beta}-IIIAR$, UCP-1, and ALDH2 polymorphisms were analyzed. Also, ACE, ${\beta}-IIAR$, ${\beta}-IIIAR$, UCP-1, and ALDH2 analyses were performed on the 100 samples of previous study who showed Taeyang characteristics. Despite of several significant differences of HLA allele frequencies between Taeum-inclined group and normal control group, this significance level was not sufficient ro support the association between constitution and HLA genes, because of the raised alpha error rate. The polymorphisrns of ACE, ${\beta}-IIAR$, ${\beta}-IIIAR$, UCP-1, and ALDH2 genes did not show relationship between Taeyang-inclined and Taeum-inclined groups, whereas BMI showed difference between Taeyang-inclined and Taeum-inclined groups. ALDH2 in Taeyang-inclined group confirmed the protective role of ALDH2*2 allele against alcoholism.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.368-373
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• 2003

This paper presents a study of low frequencies volume velocity vibration control of a smart panel in order to reduce sound transmission. A distributed piezoelectric quadratically shaped polyvinylidene fluoride (PVDF) polymer film is used as a uniform force actuator and an array of 4$\times$4 accelerometer is used as a volume velocity sensor for the implementation of a single-input single-output con rot system. The theoretical and experimental study of sensor-actuator frequency response function sho vs that this sensor-actuator arrangement provides a required strictly positive real frequency response function below about 900Hz. Direct velocity feedback could therefore be implemented with a limited gain which gives reductions of about 15㏈ in vibration level and about 8 ㏈ in acoustic power level at the (1, 1) mode of the smart Panel. It has been also shown that the shaping error of PVDF actuator could limit he stability and performance of the control system.