• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.11a
• /
• pp.821-824
• /
• 2008

This paper presents a systematic approach for estimating material performance of concrete mixture design based on satisfaction curves developed from statistical evaluation of existing or newly obtained material property related data. In performance based material design (PBMD) method, concrete material used for construction of a structure is designed considering a structure's specified performance requirements based on its usage and characteristics such as environmental conditions, structure types, expected design life, etc.Satisfaction curves express the probabilities that one component of substrates (i.e., aggregate size, cement content, etc) of concrete mixture will sustain different criterion value for a given concrete mixture design. This study presents a statistical analysis method for setting up concrete material parameter versus concrete criterion relationships in the form of satisfaction curves and for estimating confidence bounds on these satisfaction curves. This paper also presents an analysis method to combine multiple satisfaction curves to form one unique satisfaction curve that can relate the performance of concrete to a single evaluating value. Based on several evaluated mixture design examples for various material properties, the validity of the proposed method is discussed in detail.

• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.34S no.1
• /
• pp.105-114
• /
• 1997

The phase retrieval problem is concerned with the reconstruction of a signal or its fourier transform phase form the fourier transform magnitude of the signal. This problem does not have a unique solution, in general. If, however, the desired signal is minimum-phase, then it can be decided uniquely. This paper shows that we can make a minimum-phase signal by adding a delta function having a large value at the origin of an arbitrary one-dimensional signal, and a two-dimensional signal can be uniquely specified from its fourier transform magnitude if it is added by a delta function having a large value at the origin, and finally we can solve a two-dimensional phase retrieval problem by decomposing it into several ine-dimensional phase retrieval problems.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.28 no.2
• /
• pp.197-207
• /
• 1992

Fatigue life and penetration behavior were examined analytically by variety of initial front face crack length and initial crack depth. The fatigue crack shape before penetration is almost semielliptical, and the aspect ratio by calculation using the Newman-Raju's formula is smaller than the value obtained by the experiment. It is found that the crack growth behavior on the back surface after penetration is unique and can be divided into three stage a, b and c. By using the K value proposed by the authors, particular crack growth behavior and the change in crack shape can be evaluated quantitatively. It is found that fatigue life and penetration behavior were more dependent on initial front face crack length than initial crack depth.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.17 no.6
• /
• pp.1431-1440
• /
• 1993

This paper presents a new NC machine performance test and calibration system. In order to measure NC machine erros in simpler, and less time-comsuming way, some indirect measuring systems such as circular disk system and double ball bar system have been developed instead of laser interferometer. But these indirect measuring systems have shown their limits in identifying each of NC machine error sources in absolute numerical value. Therefore, we developed an unique NC machine error measurement system which provides a simple measuring process like other conventional indirect methods and still can indentify each of NC machine error sources in absolute numerical value.

• Structural Engineering and Mechanics
• /
• v.59 no.3
• /
• pp.475-502
• /
• 2016

Nanobeams are widely used as a structural element for nanodevices and nanomachines. The development of nano-sized machines depends on proper understanding of mechanical behavior of these nano-sized beam elements. Small length scales such as lattice spacing between atoms, surface properties, grain size etc. are need to be considered when applying any classical continuum model. In this study, Eringen's nonlocal elasticity theory is incorporated into classical beam model considering the effects of axial extension and the shear deformation to capture unique static behavior of the nanobeams under continuum mechanics theory. The governing differential equations are obtained for curved beams and solved exactly by using the initial value method. Circular uniform beam with concentrated loads are considered. The displacements, slopes and the stress resultants are obtained analytically. A detailed parametric study is conducted to examine the effect of the nonlocal parameter, mechanical loadings, opening angle, boundary conditions, and slenderness ratio on the static behavior of the nanobeam.

• Journal of Auto-vehicle Safety Association
• /
• v.5 no.1
• /
• pp.50-55
• /
• 2013

When it comes to commercial vehicles, their unique characteristics - center of gravity, size, weight distribution - make them particularly vulnerable to rollover. On top of that, conventional heavy vehicle brake exhibits longer actuation delays caused in part by long air lines from brake pedal to tires. This paper describes rollover prevention algorithm that copes with the characteristics of commercial vehicles. In regard of compensating for high actuating delay, predicted rollover index with short preview time has been designed. Moreover, predicted rollover index with longer preview time has been calculated by using road curvature information based on environment information. When rollover index becomes larger than specific threshold value, desired braking force is calculated in order to decrease the index. At the same time, braking force is distributed to each tire to make yaw rate track desired value.

• East Asian mathematical journal
• /
• v.27 no.3
• /
• pp.319-337
• /
• 2011

We approximate a locally unique solution of a nonlinear equation in a Banach space setting using an inexact two-step Newton-type method. It turn out that under our new idea of recurrent functions, our semilocal analysis provides tighter error bounds than before, and in many interesting cases, weaker sufficient convergence conditions. Applications including the solution of nonlinear Chandrasekhar-type integral equations appearing in radiative transfer and two point boundary value problems are also provided in this study.

• Proceeding of Spring/Autumn Annual Conference of KHA
• /
• 2005.11a
• /
• pp.51-56
• /
• 2005

The purpose of this study was to examine the needs of apartment residents for community programs by generations. For this study, the data from the focus group interview(35 participants) and the questionnaire survey(186 participants) were analyzed. The major results were as follows; 1) The residents in different generations had different characteristics and life values. Y generation showed higher value in Technology/Consumption/Individual than other generations. BB generation had higher value both in Health/Property/Family and Prudence/Reality. G generation scored a higher level in Tradition/Conservatism. 2) The residents in all generations showed a high level in needs of community programs and especially higher rates in needs of communication programs items. However, there were gaps in program needs among different generations. Therefore, the community programs should be specialized provided by considering unique needs of different generations.

• Proceeding of EDISON Challenge
• /
• 2016.03a
• /
• pp.506-509
• /
• 2016

In this paper, the multi-leg robot is designed using Teo Jansen mechanism. The purpose of this paper is to develop unique robot, which operates efficiently in any environment. In that case, speed and accuracy are required. The indication which evaluate the value is Ground Score according to the Jansen's mechanism. To optimize the Ground Score. Genetic Algorithm (GA) in MATLAB Toolbox is used, which is numerical analytic algorithm to quickly convergence into optimum point. The Optimization of value is visualized by M-Sketch. M-Sketch was useful for simulation and evaluation of mechanic's dynamic motion. The robot's draft is produced into finished product by Edison Designer.

• Proceedings of the KSRS Conference
• /
• 2002.10a
• /
• pp.673-678
• /
• 2002

A satellite remote sensing is useful for vegetation monitoring. But it has some problem. One of these, it is difficult to find a difference of vegetation surface roughness using satellite remote sensing. Each vegetation type has unique surface roughness, for example needle leaves forest, broad leaves forest and grassland. Difference of vegetation surface roughness can be detected by satellite multiangular observation. In this study, objective is to propose index of vegetation surface roughness using BRF property. General vegetation indices are calculated from nadir data of satellite data. A proposed index is calculated from two different observation zenith angle data. Two different zenith data can provide BRF (Bi-directional Reflectance Factor) property of satellite observation data. A proposed index was able to detect different value on where NDVI shows similar high value areas of rice field and forest. This index is useful for vegetation monitoring.