• Journal of the Korean Society for information Management
• /
• v.14 no.2
• /
• pp.105-122
• /
• 1997

A library for the civil engineering field goes on increasing in quantity because of the growth in construction technology and the enlargement in applicable fields of civil engineering. Most of libraries and information centers in construction companies are using Dewey Decimal Classification (DDC) or Korean Decimal Classification (KDC) to classify a library in civil engineering field. It is necessary for the library classification system to be equipped with a more standardized code system, which corresponds to the academical and technical classification for the civil engineering works. This study analyzes the defects of existing classification systems, and then suggests a new classes and divisions classification system, which facilitates to link academic information with technical data, for the civil engineering field. The proposed system is expected to make practical application of information classification system in the construc ion industry and to be applied for the revised edition of KDC.

• Journal of the Korea Society of Computer and Information
• /
• v.19 no.2
• /
• pp.21-30
• /
• 2014

The use of induction motors has been recently increasing in a variety of industrial sites, and they play a significant role. This has motivated that many researchers have studied on developing fault detection and classification systems of induction motors in order to reduce economical damage caused by their faults. To early identify induction motor faults, this paper effectively estimates spectral envelopes of each induction motor fault by utilizing a linear prediction coding (LPC) analysis technique and an expectation maximization (EM) algorithm. Moreover, this paper classifies induction motor faults into their corresponding categories by calculating Mahalanobis distance using the estimated spectral envelopes and finding the minimum distance. Experimental results show that the proposed approach yields higher classification accuracies than the state-of-the-art conventional approach for both noiseless and noisy environments for identifying the induction motor faults.

• Smart Media Journal
• /
• v.5 no.1
• /
• pp.24-29
• /
• 2016

To satisfy the needs of high-level intelligent surveillance system, it shall be able to extract objects and classify to identify precise information on the object. The representative method to identify one's identity is face recognition that is caused a change in the recognition rate according to environmental factors such as illumination, background and angle of camera. In this paper, we analyze the robust face recognition of face image by changing the distance through a variety of experiments. The experiment was conducted by real face images of 1m to 5m. The method of face recognition based on Linear Discriminant Analysis show the best performance in average 75.4% when a large number of face images per one person is used for training. However, face recognition based on Convolution Neural Network show the best performance in average 69.8% when the number of face images per one person is less than five. In addition, rate of low resolution face recognition decrease rapidly when the size of the face image is smaller than $15{\times}15$.

• KIPS Transactions on Software and Data Engineering
• /
• v.2 no.3
• /
• pp.199-204
• /
• 2013

An implementation method of real-time numeral recognizer based on gesture is presented in this paper for various information devices. The proposed algorithm steadily captures the motion of a hand on 3D open space with the Kinect sensor. The captured hand motion is simplified with PCA, in order to preserve the trace consistency and to minimize the trace variations due to noises and size changes. In addition, we also propose a new HMM using both the gradient and the positional features of the simplified hand stroke. As the result, the proposed algorithm has robust characteristics to the variations of the size and speed of hand motion. The recognition rate is increased up to 30%, because of this combined model. Experimental results showed that the proposed algorithm gives a high recognition rate about 98%.

• Journal of IKEEE
• /
• v.27 no.3
• /
• pp.319-326
• /
• 2023

In this paper, simulation and experimental results are presented, including the implementation of a digital controller for robust output voltage control of a single-phase voltage source inverters (VSIs) and total harmonic distortion (T.H.D.v) analysis. Typically, the VSIs uses a proportional integral (PI) controller for the current controller on the inner loop and a proportional resonant (PR) controller for the voltage controller on the outer loop to control the output voltage. However, non-linear loads still produce high-order odd harmonic distortion. Therefore, in this paper, a proportional multiple resonance (PMR) controller with a resonance controller for odd harmonic frequencies is proposed to suppress harmonic distortion. Analyze the frequency response of controllers for VSI plants and design PMR controllers. Through simulation, the total harmonic distortion characteristics of the output voltage are compared and verified when PI and PMR are used as voltage controllers. Both linear and non-linear loading conditions were considered. Finally, the effectiveness of the PMR controller was demonstrated by applying it to a 3kW VSIs prototype.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.38 no.4
• /
• pp.601-610
• /
• 2018

Since the building construction works are repeated vertically in a limited space, there is not a great need for the location information of each activity in the schedule management. On the other hand, civil engineering works such as road and railway projects consist of a large number of earthworks, long bridges, and long tunnels. These types of work should be controlled in a horizontal space according to the linear axis of several tens of kilometers. In other words, since most of the activities are managed in the unit of distance from the start point to the end point, it is possible to improve the efficiency of the schedule management by linking the location information of the activity with the schedule data in the schedule management system. This study presents a methodology for creating a linear schedule chart specific to a project with horizontal work space and compares the convenience with the existing Gantt chart. In addition, the methodology of linking linear schedule chart to the 4D CAD system, which is a typical BIM technology in the construction phase, is presented to improve the usability of BIM. The practical applicability of the proposed methodology was verified statistically.

• Polymer(Korea)
• /
• v.39 no.3
• /
• pp.506-513
• /
• 2015

Ethylidene norbornene (ENB) and its blends with endo-dicyclopentadiene (endo-DCPD) were prepared and reacted via the ring-opening metathesis polymerization (ROMP) reaction with the $1^{st}$ and $2^{nd}$ generation Grubbs' catalysts. Dynamic exothermic behaviors during ROMP and tensile properties after ROMP were evaluated using a differential scanning calorimeter (DSC) and a universal testing machine (UTM) for the samples, respectively. It revealed that the ROMP rate was accelerated with the less contents of endo-DCPD and under the $2^{nd}$ generation catalyst. Also, the addition of endo-DCPD and the $1^{st}$ generation catalyst resulted in higher tensile modulus and strength but lower toughness. Gel fraction measurement and fracture surface observation were made to understand the tensile properties.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.16 no.4
• /
• pp.591-598
• /
• 2021

The digital phase-locked loops(DPLL) is a circuit used for phase synchronization and has been generally used in various fields such as communication and circuit fields. State estimators are used to design digital phase-locked loops, and infinite impulse response state estimators such as the well-known Kalman filter have been used. In general, the performance of the infinite impulse response state estimator-based digital phase-locked loop is excellent, but a sudden performance degradation may occur in unexpected situations such as inaccuracy of initial value, model error, and disturbance. In this paper, we propose a minimum variance finite impulse response filter with optimal horizon for designing a new digital phase-locked loop. A numerical method is introduced to obtain the measured value interval length, which is an important parameter of the proposed finite impulse response filter, and to obtain a gain, the covariance matrix of the error is set as a cost function, and a linear matrix inequality is used to minimize it. In order to verify the superiority and robustness of the proposed digital phase-locked loop, a simulation was performed for comparison and analysis with the existing method in a situation where noise information was inaccurate.

• Journal of Navigation and Port Research
• /
• v.43 no.3
• /
• pp.172-178
• /
• 2019

Although the needs for providing resilient PNT information are increasing, threats due to the intentional RFI or space weather change are challenging to resolve. eLoran, which is a terrestrial navigation system that use a high-power signal is considered as a best back-up navigation system. Depending on the user's environment in the eLoran system, the user may use one of E-field or H-field antennas. H-field antenna, which has no restriction on setting stable ground and is relatively resistant to noise of general electronic equipment, is composed of two loops, and shows anisotropic gain pattern due to the different measurement at the two loops. Therefore, the H-field antenna's phase estimation value of signal varies depending on its direction even at the static environment. The error due to the direction of the signal should be eliminated if the user want to estimate the own position more precisely. In this paper, a method to compensate the error according to the geometric distribution between the H-field antenna and the transmitting station is proposed. A model was developed to compensate the directional error of H-field antenna based on the signal generated from the eLoran signal simulator. The model is then used to the survey measurement performed in the land area and verify its performance.

• Journal of Internet Computing and Services
• /
• v.22 no.1
• /
• pp.23-30
• /
• 2021

This paper proposes a noise-tolerant image classification system using multiple autoencoders. The development of deep learning technology has dramatically improved the performance of image classifiers. However, if the images are contaminated by noise, the performance degrades rapidly. Noise added to the image is inevitably generated in the process of obtaining and transmitting the image. Therefore, in order to use the classifier in a real environment, we have to deal with the noise. On the other hand, the autoencoder is an artificial neural network model that is trained to have similar input and output values. If the input data is similar to the training data, the error between the input data and output data of the autoencoder will be small. However, if the input data is not similar to the training data, the error will be large. The proposed system uses the relationship between the input data and the output data of the autoencoder, and it has two phases to classify the images. In the first phase, the classes with the highest likelihood of classification are selected and subject to the procedure again in the second phase. For the performance analysis of the proposed system, classification accuracy was tested on a Gaussian noise-contaminated MNIST dataset. As a result of the experiment, it was confirmed that the proposed system in the noisy environment has higher accuracy than the CNN-based classification technique.