• Journal of Drive and Control
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• v.16 no.4
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• pp.1-8
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• 2019

The HPM (High-speed Power Matching) system is an electro-hydraulic control system. It directly controls the swash plate of the pump by selecting four-loop logic based on joystick signals, pump flow, and pressure signal to improve the efficiency and controllability of construction machines. In the NFC (Negative Flow Control) system, a typical pump control system using conventional open center type MCV, the loss is continuously generated by flow through the center bypass line even when the excavator is not in operation. Also, due to the slow response of the pump that indirectly controls the flow rate using the pressure regulator, peak pressure occurs at the start or stop of the operation. Conversely, the HPM system uses an MCV without center-by-pass flow path and the swash plate of a pump for the HPM is controlled by a high-speed proportional flow control valve. As a result, the HPM system minimizes energy loss in standby state of the excavator and enables peak pressure control through rapid electro-hydraulic control of a pump. In this paper, the concept of the HPM system algorithm is introduced and the hydraulic system efficiency is compared with the NFC system using the excavator SAT (System Analysis Tool).

• The Journal of Korean Association of Computer Education
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• v.8 no.5
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• pp.109-118
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• 2005

In this paper, we present a music retrieval system that compares the geometric structure of a melody specified by a user with those in a music database. The system finds matches between a query melody and melodies in the database by analyzing both structural and contextual features. The retrieval method is based on the geometric hashing algorithm which consists of two steps; the preprocessing step and the recognition step. During the preprocessing step, we divide a melody into several fragments and analyze the pitch and duration of each note of the fragments to find a structural feature. To find a contextual feature, we find a main chord for each fragment. During the recognition step, we divide the query melody specified by a user into several fragments and search through all fragments in the database that are structurally and contextually similar to the melody. A vote is cast for each of the fragments and the music whose total votes are the maximum is the music that contains a matching melody against the query melody. Using our approach, we can find similar melodies in a music database quickly. We can also apply the method to detect plagiarism in music.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.1
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• pp.123-129
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• 2017

New mobile phones with high tech-camera and a large size memory have been recently launched and people upload pictures of beautiful scenes or unknown flowers in SNS. This paper develops a flower recognition system that can get information on flowers in the place where mobile communication is not even available. It consists of a registration part for reference flowers and a recognition part based on OpenCV for Android platform. A new color classification method using RGB color channel and K-means clustering is proposed to reduce the recognition processing time. And ORB for feature extraction and Brute-Force Hamming algorithm for matching are used. We use 12 kinds of flowers with four color groups, and 60 images are applied for reference DB design and 60 images for test. Simulation results show that the success rate is 83.3% and the average recognition time is 2.58 s on Huawei ALEUL00 and the proposed system is suitable for a mobile phone without a network.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.367-370
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• 2015

This paper proposes an improve method of the detection performance of traffic lights for autonomous driving cars. Earlier detection methods used to adopt color thresholding, template matching and based learning maching methods, but its have some problems such as recognition rate decreasing, slow processing time. The proposed method uses both detection mask and morphological preprocessing. Firstly, input color images are converted to YCbCr image in order to strengthen its illumination, and horizontal edge components are extracted in the Y Channel. Secondly, the region of interest is detected according to morphological characteristics of the traffic lights. Finally, the traffic signal is detected based on color distributions. The proposed method showed that the detection rate and processing time improved rather than the conventional algorithm about some surrounding environments.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.1
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• pp.128-135
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• 2009

Techniques for tracking the same region of physical space with the temporal sequences of images by matching the contours of constant phase show robust and stable performance in relative to the tracking techniques using or assuming the constant intensity. Using this property, we describe an algorithm for obtaining the robust motion parameters caused by the global camera motion. First, we obtain the optical flow based on the phase of spacially filtered sequential images on the region in a direction orthogonal to orientation of each component of gabor filter bank. And then, we apply the least squares method to the optical flow to determine the affine motion parameters. We demonstrate hat proposed method can be applied to the vision based pointing device which estimate its motion using the image including the display device which cause lighting condition varieties and noise.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.4
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• pp.127-133
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• 2009

To ensure access to rapidly growing video collection, video indexing is becoming more and more essential. A database for video should be build for fast searching and extracting the accurate features of video information with more complex characteristics. Moreover, video indexing structure supports efficient retrieval of interesting contents to reflect user preferences. In this paper, we propose semantic video retrieval method based on user preference. Unlikely the previous methods do not consider user preferences. Futhermore, the conventional methods show the result as simple text matching for the user's query that does not supports the semantic search. To overcome these limitations, we develop a method for user preference analysis and present a method of video ontology construction for semantic retrieval. The simulation results show that the proposed algorithm performs better than previous methods in terms of semantic video retrieval based on user preferences.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.12 s.103
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• pp.1206-1212
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• 2005

In this paper, we propose a novel antenna structure which uses the electric and magnetic currents so as to eliminate nulls on their radiation pattern. The tag antenna was matched to the conjugate impedance of the commercial tag chip using the modified double T matching network. The radiation efficiency is about $90\%$, and the bandwidth($S_{11}< -10 dB$) is 848${\~}$926 MHz. Also it shows the gain deviation between the maximum and minimum gains about 4 dB at any direction of the tag antenna at the operating frequency. The readable range of the tag is 1.7${\~}$2.4 m for an arbitrary rotation angle of the tag with a commercial tag chip.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.1
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• pp.73-82
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• 2010

Door is an important object to understand given environment and it could be used to distinguish with corridors and rooms. Doors are widely used natural landmark in mobile robotics for localization and navigation. However, almost algorithm for door recognition with camera is difficult real-time application because feature extraction and matching have heavy computation complexity. This paper proposes a method to recognize a door in corridor. First, we extract distinguished lines which have high possibility to comprise of door using Hough transformation. Then, we detect candidate of door region by applying previously extracted lines to first-stage visual fuzzy system. Finally, door regions are determined by verifying knob region in candidate of door region suing second-stage visual fuzzy system.

• Journal of the Korea Society of Computer and Information
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• v.19 no.1
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• pp.149-156
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• 2014

NGE(Nested Generalized Exemplar Method) can increase the performance of the noisy data at the same time, can reduce the size of the model. It is the optimal distance-based classification method using a matching rule. NGE cross or overlap hyperrectangles generated in the learning has been noted to inhibit the factors. In this paper, We propose the DHGen(Dominant Hyperrectangle Generation) algorithm which avoids the overlapping and the crossing between hyperrectangles, uses interval weights for mixed hyperrectangles to be splited based on the mutual information. The DHGen improves the classification performance and reduces the number of hyperrectangles by processing the training set in an incremental manner. The proposed DHGen has been successfully shown to exhibit comparable classification performance to k-NN and better result than EACH system which implements the NGE theory using benchmark data sets from UCI Machine Learning Repository.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.9
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• pp.1-10
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• 2000

This paper proposes symbol decoding schemes combined with channel estimation techniques for coded orthogonal frequency division multiplexing (COFDM) systems in fading channels. sThe proposed symbol decoding schemes are consisted of a symbol decoding technique and channel estimation techniques. The symbol decoding based on Viterbi algorithm is achieved by matching the length of branch word from encoder trellis to the codeword length of symbol candidate on decoder trellis. Three combination schemes are described and their error performances are compared. The first scheme is to combine a symbol decoding technique with a training channel estimation technique. The second scheme joins a decision directed channel estimation technique to the first scheme. The time varying channel transfer functions are tracked by the decision directed channel estimation technique and the channel transfer functions used in the symbol decoder are updated every COFDM symbol. Finally, In order to reduce the effect of additive white Gaussian noise (AWGN) between adjacent subchannels, deinterleaved average channel estimation technique is combined. The error performances of the three schemes are significantly improved being compared with that of zero forcing equalizing schemes.