• Journal of the Korea Concrete Institute
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• v.13 no.5
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• pp.447-456
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• 2001

Many investigators have tried to represent the nonlinear behavior of stress-strain relationship of concrete using mathematical curves. Most of empirical expressions for stress-strain relationship, however, have focused on old age concrete, and were not able to represent well the behavior of concrete at an early age. Where wide understanding on the behavior of concrete from early age to old age is very important in evaluating the durability and service life of concrete structures. In this paper, effect of 5 different strength levels and ages of from 12 hours to 28 days on compressive stress-strain relationship was observed experimentally and analytically. Tests were carried out on $\phi$100${\times}$200mm cylindrical specimens water-cured at 20${\pm}$3$^{\circ}C$. An analytical expression of stress-stain relationship with strength and age was developed using regression analyses on experimental results. For the verification of the proposed model, the model was compared with present and existing experimental data and some existing models. The analysis shows that the proposed model predicts well experimental data and describes well effect of strength and age on stress-strain relationship.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.3C
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• pp.83-91
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• 2005

We analyze the performance of an adaptive hybrid search code acquisition algorithm for direct-sequence code division multiple access (DS-CDMA) systems under slowly-moving mobile environments. The code acquisition algorithm is designed to provide the desired feature of constant false alarm rate (CFAR) to cope with nonstationarity of the interference in CDMA forward links. An analytical expression for the mean acquisition time is first derived and the probabilities of detection, miss, and false alarm are then obtained for frequency-selective Rayleigh fading environments. The fading envelope of a received signal is assumed to be constant over the duration of post-detection integration (PDI), considering slow fading environments. Finally, the performance of the designed code acquisition algorithm shall be evaluated numerically to examine the effect of some design parameters such as the sub-window size, size of the PDI, decision threshold, and so on, considering cdma2000 environments.

• Proceedings of the Korean Nutrition Society Conference
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• 2002.05a
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• pp.29-41
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• 2002

While the sequencing of several genomes was underway, several advanced techniques in genetics, molecular biology and protein chemistry emerged. Within the nutritional sciences, while the focus on nutrition education, epidemiology and public health aspects remains essential; it is crucial to incorporate the new advances in gene and protein discovery in nutritional studies. Nutrition is a discipline that has always integrated social, biochemical and physiological sciences from the studies at the molecule level to studies at the population level. For this reason, nutritionists are in a prime position to readily incorporate the current genomics approaches in nutrition research, All the available analytical techniques can and should be used in modern nutritional sciences. These include genetics, genomics, proteomics and metabolomics which also require integration and use of bioinformatics and computational methods for data analysis and management. These applications will be briefly reviewed with a primary focus on what the genomics and genetics approaches offer to nutritionists. We will use one of our research focus areas to illustrate uses of some of these applications in obesity-hypertension research. Our central hypothesis is that adipose tissue is an endocrine organ that plays a major role in obesity and related hypertension. We are primarily studying the renin angiotensin system (RAS). We provide evidence from our own studies and others for the paracrine as well as endocrine role of adipocyte-derived angiotensin II in adipocyte gene expression, adiposity and blood pressure regulation. Both cell culture studies as well as knockout and transgenic mice models are used to test our hypothesis. Genomics and proteomics technologies are currently developed to complement our physiological and molecular studies on the RAS and for a fine analysis of this system and its function in health and disease.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.6
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• pp.2046-2053
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• 2010

This study reviewed the previous research materials and made a positive investigation to identify the structural interrelation of caddies' emotional labor, job stress and turnover intention. Some analytical findings are as follows: First, the job stress increases in proportion as the emotional labor. Second, the turnover intention is not in proportion as the frequency of emotional display or the subordinate element of the emotional labor but the degree of the emotional expression and dissonance. Third, the turnover intention is in proportion as the job stress. In other words, the higher the emotional labor, the more the job stress and turnover intention. Consequently, the caddies should be highly qualified to express themselves according to their job conditions. Also, the stronger the caddies' job stress, the more their turnover intention. It is necessary to use the leadership to relieve the job stress and motivate the caddies to have the pride. My solution will have a positive effect on lessening the job stress and turnover intention.

• Proceedings of the Korean Nutrition Society Conference
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• 2002.06a
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• pp.598-603
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• 2002

While the sequencing of several genomes was underway, several advanced techniques in genetics, molecular biology and protein chemistry emerged. Within the notritional sciences, while the focus on nutrition education, epidemiology and public health aspects remains essential; it is crucial to incorporate the new advances in gene and protein discovery in nutritional studies. Nutrition is a discipline that has always integrated social, biochemical and physiological sciences from the studies at the molecule level to studies at the population level. for this reason, nutritionists are in a prime position to readily incorporate the current genomics approaches in nutrition research. All the available analytical techniques can and should be used in modem nutritional sciences. These include genetics, genomics, proteomics and metabolomics which also require integration and use of bioinformatics and computational methods for data analysis and management. These applications will be briefly reviewed with a primary focus on what the genomics and genetics approaches offer to nutritionists. We will use one of our research focus areas to illustrate uses of some of these applications in obesity-hypertension research. Our central hypothesis is that adipose tissue is an endocrine organ that plays a major role in obesity and related hypertension. We are primarily studying the renin angiotensin system (RAS). We provide evidence from our own studies and others for the paracrine as well as endocrine role of adipocyte-derived angiotensin II in adipocyte gene expression, adiposity and blood pressure regulation. Both cell culture studies as well as knockout and transgenic mice models are used to test our hypothesis. Genomics and proteomics technologies are currently developed to complement our physiological and molecular studies on the RAS and for a fine analysis of this system and its function in health and disease.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.11B
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• pp.698-706
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• 2005

In this paper, we investigate the parameters of the IEEE 802.11e MAC protocol, CWmin and AIFS, in terms of their capability of QoS control. The delay and the bandwidth performances are selected as the QoS medics to examine the characteristics of those parameters. A policy on MAC parameters usage, thereby, is proposed. We regard the MAC-level traffic classification as the differentiation in the channel accessibility, and thus the delay differentiation is referred to a main issue of the class-level QoS control. Realizing the tight relationship between the delay performance and the parameter AIFS, we derive an analytical expression of their relationship through an analysis of the MAC mechanism. Various simulations are examined which show the validity of our assertions, and a policy on the parameters usage is proposed based on those observations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.8A
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• pp.592-599
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• 2009

In this paper, we consider multiuser multi-input/multi-output antenna systems with zero-forcing receivers in downlink. In this case, to exploit multiuser diversity, spatial-division multiple access (SDMA) system allows to assign different users to a part of transmit antennas at the base station whereas spatial-division multiplexing (SDM) system assigns all antennas to single user's data stream. In this paper, we present analytical frameworks to evaluate performance of these systems. We first analyze the performance of these two systems by deriving closed-form expressions of achievable throughput. Numerical results show that the derived expressions are very tight. In addition, we approximate the capacity expression of SDM and SDMA systems and compare the SDM with the optimal case.

• Journal of the Korea Convergence Society
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• v.11 no.1
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• pp.109-117
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• 2020

This study aims to analyze typographic expressions used in recent fashion trends from the perspective of conceptual art and thus identify a variety of meanings. Towards this end, theoretical considerations were made vis-à-vis the main concepts of research, such as typography and conceptual art, and the ready-made, documentation, intervention and language, which are the expressive features of conceptual art, were applied to fashion typography as analytical frameworks. The results are as follows. The ready-made appears in a way that borrows or transforms the visual identity of other brands, and documentation is utilized in a way that lays tautological or contradictory texts together. Intervention arises, while leading to more complex layers of meaning when borrowing the visual identity of the brand, which is conceptually irrelevant. The language is expressed as statements about contemporary social issues, such as environmental protection, ethical consumption and gender problems. Based on the findings of this study, it can be confirmed that in fashion design, typography serves as an effective marketing tool and a medium of social statements. Moreover, it can expand into the possibility of generating new meanings as a novel way of visual expression.

• Investigative Magnetic Resonance Imaging
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• v.20 no.1
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• pp.27-35
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• 2016

Purpose: Among RF pulses, a sinc pulse is typically used for slice selection due to its frequency-selective feature. When a sinc pulse is implemented in practice, it needs to be apodized to avoid truncation artifacts at the expense of broadening the transition region of the excited-band profile. Here a sinc pulse tailored by a new apodization function is proposed that produces a sharper transition region with well suppression of truncation artifacts in comparison with conventional tailored sinc pulses. A multiband pulse designed using this newly apodized sinc pulse is also suggested inheriting the better performance of the newly apodized sinc pulse. Materials and Methods: A new apodization function is introduced to taper a sinc pulse, playing a role to slightly shift the first zero-crossing of a tailored sinc pulse from the peak of the main lobe and thereby producing a narrower bandwidth as well as a sharper pass-band in the excitation profile. The newly apodized sinc pulse was also utilized to design a multiband pulse which inherits the performance of its constituent. Performances of the proposed sinc pulse and the multiband pulse generated with it were demonstrated by Bloch simulation and phantom imaging. Results: In both simulations and experiments, the newly apodized sinc pulse yielded a narrower bandwidth and a sharper transition of the pass-band profile with a desirable degree of side-lobe suppression than the commonly used Hanning-windowed sinc pulse. The multiband pulse designed using the newly apodized sinc pulse also showed the better performance in multi-slice excitation than the one designed with the Hanning-windowed sinc pulse. Conclusion: The new tailored sinc pulse proposed here provides a better performance in slice (or slab) selection than conventional tailored sinc pulses. Thanks to the availability of analytical expression, it can also be utilized for multiband pulse design with great flexibility and readiness in implementation, transferring its better performance.

• Structural Engineering and Mechanics
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• v.9 no.5
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• pp.449-467
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• 2000

The natural frequencies and the corresponding mode shapes of a non-uniform beam carrying multiple point masses are determined by using the analytical-and-numerical-combined method. To confirm the reliability of the last approach, all the presented results are compared with those obtained from the existing literature or the conventional finite element method and close agreement is achieved. For a "uniform" beam, the natural frequencies and mode shapes of the "clamped-hinged" beam are exactly equal to those of the "hinged-clamped" beam so that one eigenvalue equation is available for two boundary conditions, but this is not true for a "non-uniform" beam. To improve this drawback, a simple transformation function ${\varphi}({\xi})=(e+{\xi}{\alpha})^2$ is presented. Where ${\xi}=x/L$ is the ratio of the axial coordinate x to the beam length L, ${\alpha}$ is a taper constant for the non-uniform beam, e=1.0 for "positive" taper and e=1.0+$|{\alpha}|$ for "negative" taper (where $|{\alpha}|$ is the absolute value of ${\alpha}$). Based on the last function, the eigenvalue equation for a non-uniform beam with "positive" taper (with increasingly varying stiffness) is also available for that with "negative" taper (with decreasingly varying stiffness) so that half of the effort may be saved. For the purpose of comparison, the eigenvalue equations for a positively-tapered beam with five types of boundary conditions are derived. Besides, a general expression for the "normal" mode shapes of the non-uniform beam is also presented.