• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2271-2274
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• 2005

The desired ZMP is different from the actual ZMP of a humanoid robot during actual walking and stand upright. A humanoid robot must maintain its stable posture although external force is given to the robot. A humanoid robot can know its stability with ZMP. Actual ZMP may be moved out of the foot-print polygons by external disturbance or uneven ground surfaces. If the position of ZMP moves out of stable region, the stability can not be guaranteed. Therefore, The control of the ZMP is necessary. In this paper, ZMP control algorithm is proposed. Herein, the ZMP control uses difference between desired ZMP and actual ZMP. The proposed algorithm gives reaction moment with ankle joint when external force is supplied. 3D simulator shows motion of a humanoid robot and calculated data.

• Journal of information and communication convergence engineering
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• v.7 no.4
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• pp.442-448
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• 2009

This paper proposes a fingerprint image processing algorithm to accurately extract minutiae in the process of fingerprint recognition. We improved the matching accuracy of low quality fingerprint images by using effective ridge vector and ridge probability. The proposed algorithm improves the clarity of ridge structures and reduces undesired noise. We collected thumb print images from 10 individuals 5 separate times each, in total using 50 thumbprints. We registered one of the five thumbprint images from each individual to match the registered one with the other four thumbprint images, and alternated the registered thumbprint image. We matched thumbprints 20 times for each individual. In total, we conducted 200 matches for the thumbprints from the 10 individuals. We improved the verification accuracy and reliability compared to conventional methods.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.167-168
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• 2019

Lately, variety of algorithms using encryption technology has been adopted as methods of unlocking smartphone. It is advancing toward the direction to solve through human biometrics technology which has already succeeded in commercialization. These include finger print recognition, face recognition, and iris recognition. In this study, we selected biometrics recognition technology and pattern recognition and password input methods which are already commercialized as evaluation items. The evaluation items are five algorithms including finger print recognition, face recognition iris recognition, pattern recognition and password input method. Based on these algorithms, analytic hierarchy process is used to analyze the preference of smartphone users. Also, the theoretical implications are presented based on the analysis results.

• Journal of Advanced Navigation Technology
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• v.12 no.5
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• pp.483-493
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• 2008

For effective wireless localization utilizing signal strength measurements based on IEEE 802.11 WLAN standard diversity of mobile hardware, characteristics of is one of the important problems to be considered for advanced location-based services. For improved accuracy regardless of a bias originating from the mobile hardware characteristics, this paper proposes a new localization algorithm, which is named as the hybrid Kriging algorithm. To evaluate the performance characteristics of the proposed algorithm, simulation and experiment results are illustrated. By the simulation and experiment result, the proposed algorithm is more accurate than the well-known location finger-print method given the same density of reference measurements.

• The KIPS Transactions:PartB
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• v.15B no.4
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• pp.307-314
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• 2008

This paper presents a new robust watermarking method for curves that uses informed-detection. To embed watermarks, the presented algorithm parameterizes a curve using the B-spline model and acquires the control points of the B-spline model. For these control points, 2D mesh are created by applying Delaunay triangulation and then the mesh spectral analysis is performed to calculate the mesh spectral coefficients where watermark messages are embedded in a spread spectrum way. The watermarked coefficients are inversely transformed to the coordinates of the control points and the watermarked curve is reconstructed by calculating B-spline model with the control points. To detect the embedded watermark, we apply curve matching algorithm using inflection points of curve. After curve registration, we calculate the difference between the original and watermarked mesh spectral coefficients with the same process for embedding. By calculating correlation coefficients between the detected and candidate watermark, we decide which watermark was embedded. The experimental results prove the proposed scheme is more robust than previous watermarking schemes against print-scan process as well as geometrical distortions.

• Special Issue of the Society of Naval Architects of Korea
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• 2009.09a
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• pp.115-122
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• 2009

In shipbuilding process, automated marking systems are used to print steel part information on the steel plate. Especially, an automated marking system with a moving ink-head prints characters on each block, which divide the steel plate into a fixed size. Therefore it is necessary to split characters, because some characters can be extended into several blocks. Particularly the algorithm, which splits characters, must guarantee its printing quality in any direction since characters can be printed by any angle.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.45 no.2
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• pp.48-55
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• 2022

The color image of the brand comes first and is an important visual element that leads consumers to the consumption of the product. To express more effectively what the brand wants to convey through design, the printing market is striving to print accurate colors that match the intention. In 'offset printing' mainly used in printing, colors are often printed in CMYK (Cyan, Magenta, Yellow, Key) colors. However, it is possible to print more accurate colors by making ink of the desired color instead of dotting CMYK colors. The resulting ink is called 'spot color' ink. Spot color ink is manufactured by repeating the process of mixing the existing inks. In this repetition of trial and error, the manufacturing cost of ink increases, resulting in economic loss, and environmental pollution is caused by wasted inks. In this study, a deep learning algorithm to predict printed spot colors was designed to solve this problem. The algorithm uses a single DNN (Deep Neural Network) model to predict printed spot colors based on the information of the paper and the proportions of inks to mix. More than 8,000 spot color ink data were used for learning, and all color was quantified by dividing the visible light wavelength range into 31 sections and the reflectance for each section. The proposed algorithm predicted more than 80% of spot color inks as very similar colors. The average value of the calculated difference between the actual color and the predicted color through 'Delta E' provided by CIE is 5.29. It is known that when Delta E is less than 10, it is difficult to distinguish the difference in printed color with the naked eye. The algorithm of this study has a more accurate prediction ability than previous studies, and it can be added flexibly even when new inks are added. This can be usefully used in real industrial sites, and it will reduce the attempts of the operator by checking the color of ink in a virtual environment. This will reduce the manufacturing cost of spot color inks and lead to improved working conditions for workers. In addition, it is expected to contribute to solving the environmental pollution problem by reducing unnecessarily wasted ink.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.10
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• pp.1537-1541
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• 2010

An inkjet printing system for printed electronics was developed. In this study, a printing algorithm was mainly discussed. In order to print a pattern image at a target location, we developed a hardware and software algorithm for determining the distances between a substrate camera and the selected nozzles. We implemented a vector-printing algorithm where AutoCAD dxf file was used for XY motion control and for printing. We also developed printing method using bitmap images. The technical issues in using CAD drawings and bitmap images were discussed.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.592-595
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• 2004

Recently the numbers of patent about the technology for mobile payment with Ie or bluetooth-chip are being increased more and more. The reasons of patent increment for mobile payment are advancement of wireless internet technology and rising of customer's request for it. The customer wants to be able to pay for purchase, tax and aid with own mobile phone. So every mobile service provider applies for patents about that competitively. And in the near future the biometrics is generalized in the mobile payment system. Especially the payment service of iris recognition is significant technique in this area for the future prospect. The biometrics of iris is an accurate authentication method because it has about 250 distinguish parameters to the finger print's 30. The biometrics of iris can recognize and identify a person for 2 seconds. But the image of iris is changed by transformation of body in the life. And the existing iris authentication system has problem that can be miss-recognized. In this paper, we propose the new method that reduces miss-recognizing rate with Renewable Iris Authentication Algorithm(RIAA) in mobile system.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.113-116
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• 2008

This work presents numerical optimization for design of staggered arrays of dimples printed on opposite surfaces of a cooling channel with a fast and elitist Non-Dominated Sorting of Genetic Algorithm (NSGA-II) of multi-objective optimization. As Pareto optimal front produces a set of optimal solutions, the trends of objective functions with design variables are predicted by hybrid multi-objective evolutionary algorithm. The problem is defined by three non-dimensional geometric design variables composed of dimpled channel height, dimple print diameter, dimple spacing and dimple depth to maximize heat transfer rate compromising with pressure drop. Twenty designs generated by Latin hypercube sampling were evaluated by Reynolds-averaged Navier-Stokes solver and the evaluated objectives were used to construct Pareto optimal front through hybrid multi-objective evolutionary algorithm. The optimum designs were grouped by k-mean clustering technique and some of the clustered points were evaluated by flow analysis. With increase in dimple depth, heat transfer rate increases and at the same time pressure drop also increases, while opposite behavior is obtained for the dimple spacing. The heat transfer performance is related to the vertical motion of the flow and the reattachment length in the dimple.