• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.7
• /
• pp.237-244
• /
• 2016

The workability of mortar determines its construction performance in a structure showing its designed resistance to external loads. Measuring the rheological properties of mortar is one way of quantifying its workability, but its field-applications are limited due to economical and spatial issues. The robustness of the slump flow test allows its use for evaluating the workability of mortar, even though it is a rather qualitative test method. This paper proposes a channel flow test and develops a correlation between its result and the rheological properties of mortar. The volume-of-fluid simulation for the channel flow test was accomplished, and a numerical database for the correlation was composed. A correlation model to estimate the rheological properties of mortar using the results of the channel flow test as inputs is proposed.

• Proceedings of the Korea Contents Association Conference
• /
• 2009.05a
• /
• pp.235-238
• /
• 2009

The character design is part of a culture. That is, it is not just an object but it reflects the cultural tendency and context where it is visualized. It's potential as a cultural medium of communication become pervasive in the field. One of good sources of characters is the classics which represent the nation's culture and history. The topic of this presentation is to show how a character in the Buddhist story, the Monkey King, designed differently in different context. For the purpose, the animation on the Monkey King in China, Japan and Korea are reviewed and analyzed. The result shows that the same animation character has been designed in different way in different context and it reflects the cultural tendency of the country. For example, Koreans tend to emphasize the global feature of the character. In case of Chinese, however, the character designer emphasizes traditional value. Finally, the designer in Japan tries to put their cultural element in detailed part of the character that makes it appeal to the public.

• The Journal of the Korea Contents Association
• /
• v.18 no.5
• /
• pp.215-229
• /
• 2018

The purpose of this study was to examine the structural relationships among factors affecting teachers' robot-based SW education acceptance in primary school. In addition, this study investigated moderating effects of gender, age, and experience. For this purpose, 171 elementary school teachers participated in this study and structural equation modeling analyses were employed to examine the causal relationships among variables. The result of this study showed that perceived ease of use, perceived usefulness, personal innovativeness had direct effects on attitude. Furthermore, attitude mediated relationships between perceived usefulness, perceived ease of use, personal innovativeness and intention to use. Third, the moderating effects of experience between perceived usefulness, personal innovativeness and attitude were significant, but gender and age were not significant on all paths. Based on the results of this study, successful teaching practices, cases, and contents should be shared with teachers. Also, continuous supports and differentiated strategies based on experience are needed.

• Tunnel and Underground Space
• /
• v.16 no.6 s.65
• /
• pp.495-505
• /
• 2006

Calculating the distribution of stresses and displacements around a circular tunnel excavated in infinite isotropic rock mass subjected to hydrostatic stress condition is one of the basic problems in rock engineering. While closed-form solutions for the distribution are known if rock masses are considered as elastic, perfectly plastic, or brittle-plastic media, a few numerically approximated solutions based on various simplifying assumptions have been reported for strain-softening rock mass. In this study, a simple numerical method is introduced for the analysis of strain-softening behavior of the circular tunnel in Mohr-Coulomb rock mass. The method can also applied to the analysis of the tunnel in brittle-plastic or perfectly plastic media. For the brittle-plastic case where closed-formsolution exists, the performance of the present method is verified by showing an excellent agreement between two solutions. In order to demonstrate the strain-softening behaviors predicted by the proposed method. a parameter study for a softening index is given and the construction of ground reaction curves is carried out. The importance of defining the characteristics of dilation in plastic analysis is discussed through analyzing the displacements near the surface of tunnel.

• Journal of Korean Society of Steel Construction
• /
• v.13 no.2
• /
• pp.191-200
• /
• 2001

This paper presents buckling analysis of the cylindrical shell subjected to axial loads using numerical method. The modeling method, appropriate element type, and number of element are recommended by comparing with analytical solution. Based on the parametric study, buckling stress decreases significantly as the diameter-thickness ratio increases. These results are different from those obtained from buckling analysis of columns. The number of buckling half-wave in circumferential direction decreases as the diameter-height ratio increases. Buckling stress increases 1~2% as the thickness of base plate increases. Therefore the effect of base plate on buckling strength for cylindrical shell can be disregarded. Buckling stress significantly decreases as the amplitude of initial geometric imperfection used for calculating buckling stress is developed and it shows a good agreement with numerical results.

• Journal of Digital Contents Society
• /
• v.19 no.3
• /
• pp.569-577
• /
• 2018

Near-Field Communication(NFC) is a useful technology that is receiving worldwide attention. NFC mobile payment systems are being developed by many technology companies including financial institutions especially for the public transportation. In this research we find several factors for the intention to adopt NFC payment system. We surveyed 355 respondents who live in Ho Chi Minh city, Vietnam which became more interested by Korean as a post China country to test our research hypothesis. Using Technology Acceptance Model(TAM) we find that the factors of Social influence, Trust, Security, and Users' Convenience play the significant role to the factor of Intention to Use of NFC payment system.

• Journal of the Korean Geotechnical Society
• /
• v.19 no.6
• /
• pp.245-259
• /
• 2003

This paper deals with an Umbrealla Arch Reinforcement Method (UARM) in tunnelling. It is known that the mechanism of the reinforcement system is too complex to be simulated in existent finite element (FE) frameworks when considering its complex geometry of pipe arrangements and contribution of each component of the reinforcement to reinforcing effect. In this study a 3-D elastoplastic FE procedure is, therefore, proposed by introducing homogenisation technique, which is used to define mathematically elastic as well as elastoplastic characteristics of a reinforced ground material as a composite. A number of practical suggestions are addressed considering staged constructions of tunnels. For illustrative purposes, a series of parametric studies are undertaken and anisotropic characteristics of the reinforced ground as well as effects of the reinforcement on tunnel convergences are investigated. It is found that the reinforced ground material defined in homogenisation framework has its mechanical characteristics reasonably representing inherent geometrical and quantitative characteristics of each of constituents.

• Journal of the Microelectronics and Packaging Society
• /
• v.15 no.2
• /
• pp.55-61
• /
• 2008

This paper shows quantitative reliability evaluations of a Bluetooth module through extending previous qualitative methods limited to structure reliability tests and solder joint reliability tests for Bluetooth modules. Accelerated Life Testing (ALT) of the modules using temperature difference in temperature cycling as an accelerated stress was conducted for quantitative reliability evaluation under field environment conditions. Lifetime distribution parameters were estimated using the failure times obtained through the ALT, and then Coffin-Manson model was implemented. Results of the ALT showed that the failure mode of the modules was open and the failure mechanisms are both crack and delamination. The ALT reproduced the failure mode and mechanisms of failed Bluetooth modules collected from the field. Further, a quantitative reliability evaluation method with respect to various temperature differences in temperature cycling was proposed in this paper. $B_{10}$ lifetime of the module for the temperature difference $70^{\circ}C$ using the proposed method would be estimated as about 4 years.

• The Journal of Korean Physical Therapy
• /
• v.11 no.2
• /
• pp.81-92
• /
• 1999

중추신경계의 미주신경동쪽핵(DMV)내 유사핵분열후 신경세포로 외래 유전자를 전달하는 매개체로서 pseudorabies 바이러스(PRV)의 유전자 조작기술은 흰쥐의 결장내로 PRV를 주입시킨 후 복잡한 신경로 추적에 관한 연구에서 하나의 바이러스에 의해 얻어지는 것보다 더욱 유용한 결과산출이 가능하게 하였다. 본 연구에서는 흰쥐의 생체내 실험모델로 하나의 바이러스 또는 이중 바이러스 주입에 PRV의 유전자 조작된 2종 바이러스를 사용하였다. 이 2종의 바이러스는 PRV의 Bartha 종에서 유래되었지만 면역조직화학적으로 검출할 수 있는 동일한 유전산물을 산출할 수 있도록 구성되었다. PRV-BaBlu는 PRV 게놈의 Us 구역 중 gC 자리에 lacZ 유전자를 삽입하여 산출되었는데 $\beta-galactosidase$ 발현은 이 바이러스에 감염된 신경원의 독특한 표시자로 나타났다. PRV-D는 2가지 단계에 의해 조성되었는데 첫째, PRV-Bartha의 Us 구역의 일부 유전자를 제거하고, 야생형인 PRV-Be DNA로 복구시켰는데 이로써 PRV-D는 PRV-Bartha 또는 PRV-Bablu에 존재하고 있지 않는 외피 당단백질인 gE와 gI를 지니게 되었다. 본 연구의 결과는 다음과 같았다. 첫째, PRV-D의 개별적 접종에 의해 얻어진 감염은 PRV-BaBlu에 의한 동일 신경회로의 감염보다 유의하게 빨랐다. 둘째, 유전자 조작된 PRV의 변이종은 변이종 상호간 및 부모 바이러스와 상이하였다. PRV-D는 PRV-Bartha 또는 PRV-BaBlu보다 감염독성이 더 강했고, PRV-BaBlu는 PRV-Bartha보다 감염독성이 약했다. 셋째, 결장을 지배하는 미주신경동쪽핵내 신경원은 변이종 바이러스들을 동시에 접종하였을 경우 이중감염을 나타내었다.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.19 no.5
• /
• pp.369-377
• /
• 1999

Recently, it is gradually raised necessity that thickness of thin film is measured accuracy and managed in industrial circles and medical world. Ultrasonic signal processing method is likely to become a very powerful method for NDE method of detection of microdefects and thickness measurement of thin film below the limit of ultrasonic distance resolution in the opaque materials, provides useful information that cannot be obtained by a conventional measuring system. In the present research. considering a thin film below the limit of ultrasonic distance resolution sandwiched between three substances as acoustical analysis model, demonstrated the usefulness of ultrasonic signal processing technique using information of ultrasonic frequency for NDE of measurements of thin film thickness. Accordingly, for the detection of delamination between the junction condition of boundary microdefect of thin film sandwiched between three substances the results from digital image processing.