• Journal of the Korean Society for Precision Engineering
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• v.17 no.7
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• pp.156-161
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• 2000

Least Squares and Minimum Zone method are known for obtaining a datum or a continuous approximate function of measured data. This study is for a Minimum Zone algorithm for a circle, which is useful to obtain the exact roundness from the reference circle of measured data. The proposed method is compared with the Least Squares Limacon method and Chrystal-Peirce algorithm. A computational algorithm for the Minimum Zone circle is suggested and results in less roundness than the other two methods. This Minimum Zone circle method will be used for other geometrical measured data, such as plane or sphere for obtaining the exact flatness or sphericity.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.13-14
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• 2003

Burgess?s concentric zone model is a famous theory in the geography of city. However, the zone border line drawing method was uncertain. We have developed the method of drawing the border using land use images.

• Journal of the Korean GEO-environmental Society
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• v.8 no.3
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• pp.35-40
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• 2007

The vertical drain method recently being used in Korea is divided into the sand drain method, the pack drain method, the paper drain method, and the PBD method according to the drainage. However, these methods generate the disturbed zone called the smear zone when the drainage is penetrated into the in-situ ground. The characteristics of the smear zone generated cause the problems that the coefficient of permeability decreases and the consolidation time becomes longer than expected in the design. Although the size of the smear zone is a very important factor directly influencing the degree of consolidation, in the existing studies, the general value for the size of the smear zone proposed has been used in the design. However, the size of the smear zone proposed by the existing studies cause a loss of economical efficiency because of the inaccuracy of the design. Hence, in this study, the characteristics on the size of the smear zone were analyzed by carrying out the three dimensional numerical analysis and the method to determine the conversion size of the smear zone considering the change of the coefficient of permeability was proposed in order to consider the change of the coefficient of permeability in the actual design.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5D
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• pp.763-769
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• 2006

Gravity Model estimates target year's distributed trips using three variables like as origin zone's trip production, destination zone's trip attraction and traffic impedance between origin zone centroid and destination zone centroid. Estimating inner zone trip by gravity model is impossible because traffic impedance of inner zone has "0" value. So till today, for estimating inner zone trips, other methods like growth factor model are used. This study proposed inner zone trip estimation method that calculates inner zone's traffic impedance using established gravity model and estimates inner zone trips by putting calculated traffic impedance into the gravity model. 1988 year's surveyed O-D as basic year's O-D, proposed method's and existing methods(growth factor method and regression model)'s estimated results of 1992 year's and 2004 year's were compared with each year's real O-D by $x^2$, RMSE, Correlation coefficient. And resulted that the proposed method is superior than other existing methods.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.3
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• pp.197-205
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• 2004

The relationships were studied between the range of hardening zone and the intensity of vacuum pressure in case of applying vacuum consolidation drainage method for soil improvement. A testing apparatus was made to measure the range of hardening zone varying the water content and the intensity of vacuum pressure for 3 different the highly compressible dredged clays(Gwangyang, Busan and Mokpo). In case of applying high vacuum pressure, the hardening zone is not spreaded as compared to low vacuum pressure because of the clogging of drainage and developed hardening zone near the drainage.

• Journal of the Korean Society of Safety
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• v.23 no.4
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• pp.7-12
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• 2008

This study proposes integrity evaluation method of weld zone in titanium using titanium distance amplitude characteristics curve(TDACC) and ultrasonic signals. For these purposes, the ultrasonic signals for porosity defects of weld zone in titanium are acquired in the type of time series data and echo strength. 4 lines in the DACC indicated damage evaluation standard of weld zone in titanium. The acquired ultrasonic signals agree fairly well with the measured results of reference block and sensitivity block(defect location, bean1 propagation distance, echo strength, etc). The proposed TDACC in this study agree fairy well with the measured results of weld zone in titanium(weld defects as porosity). The proposed TDACC in this study can be used for integrity evaluation of weld zone in titanium.

• Transactions of the Korean Society of Mechanical Engineers
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• v.8 no.5
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• pp.469-475
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• 1984

In dual phase steel composed of martensite and ferrite which are different in deformation behavior, the quantitative estimation of fracture toughness is investigated by the R-curve method and the stretched zone method of JSME Sool. In the homogeneous material J$_{IC}$ value measured by the R-curve method and the stretched zone method are almost equivalent each other, but in the inhomogeneous material J$_{IC}$ value by the stretched zone method is overestimated than that by the R-curve method. Such a overestimation for the J$_{IC}$ is due to the continuous plastic blunting of ferrite after the stretched zone width in martensite reached critical value which overmeasures the critical stretched zone width.width.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.06a
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• pp.119-127
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• 2003

For the calculation of internal stability, the hypothesis in conventional design is on the basis of two distinct zones, which are‘active zone’and‘passive zone’. This means that there is an abrupt discontinuous transition from active to passive states across a potential failure line. The existence of a discontinuity of this nature appears physically unreasonable, especially from kinematic considerations. A series of pull-out model tests was undertaken from a wall being rotated about the toe to find the strain distribution mobilized from near the wall face into the deep, stable zone through the centre plane. With this finding of transition zone, the objective of study is aiming at identifying the likely effect of this zone in designing method by comparing with the prevailing design method.

• IEMEK Journal of Embedded Systems and Applications
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• v.11 no.3
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• pp.135-141
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• 2016

Indoor zone-based services have continuously become popular by increased prevalence of smartphones. Bluetooth and ultrasound can be used for zone detection. However, bluetooth does not guarantee precise zone detection if the signal degrades due to the obstacles. Ultrasound can be easily forged by recording sound on the smartphone. For that reason, zone detection based on ultrasound has a security hole. To remedy each limitation, we propose an advanced zone detection method, that combines bluetooth and ultrasound. An authentication server issues a one-time password to the user over bluetooth. The user generates an ultrasound signal that encodes the password. In this manner, the proposed method ensures secure and accurate zone detection.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11b
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• pp.235-239
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• 2000

For the calculation of internal stability, the hypothesis in conventional design is on the basis of two distinct zones, which are 'active zone' and 'passive zone'. This means that there is an abrupt discontinuous transition from active to passive states across a potential failure line. The existence of a discontinuity of this nature appears physically unreasonable, especially from kinematic considerations. A series of pull-out model tests was undertaken from a wall being rotated about the toe to find the strain distribution mobilized from near the wall face into the deep, stable zone through the centre plane. With this finding of transition zone, the objective of study is aiming at identifying the likely effect of this zone in designing method by comparing with the prevailing design method.