• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.11
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• pp.1133-1136
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• 2011

In this paper, we proposed a collinear antenna with a stripline structure for IEEE 802.11b/g applications in ISM (Industrial, Scientific, Medical) band of 2.4~2.5 GHz, which supplements disadvantages of COCO(Coaxial Collinear) antenna and OMA(Omnidirectional planar Microstrip Antenna). By using the proposed 4-layer substrate, we obtained improved performances and advantages in production compared with the existing antenna. In order to get antenna arrays, the same phase structure is designed by alternatively connecting outer conductor to inner conductor with ${\lambda}$/2 antenna element, and the substrate of FR4 epoxy (${\epsilon}_r$=4.4, tan${\delta}$=0.02) was used for the actual implementation. The maximum gain of about 4.93 dBi was measured, which leaded to a little improved gain of 0.33 dBi in comparison to the existing OMA structure.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.477-480
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• 2002

Transparency of position that provide quick service regardless of physical position to users in distribution computing environment is getting into prominence and is developed in component form that many application softwares take advantage of distributed object technology. Because design object in distribution computing environment and OMG introduces OMA for embody, defined CORBA by standard of distributed object technology on OMA's abstract picture object model. Security service in CORBA platform is very important. Present object security service in distribution computing environment that refer standard of sorority and security models of distribution computing platform in CORBA in this treatise and follow in CORBA security service rules.

• Korean Chemical Engineering Research
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• v.56 no.1
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• pp.125-132
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• 2018

The direct synthesis of $C_2$ chemical directly from methane was studied by employing catalysts with ordered mesopores in a dielectric barrier discharge plasma reactor. The reaction was carried out using MgO/OMA (ordered mesoporous alumina), $MgO/{\gamma}-Al_2O_3$ and $MgO/{\alpha}-Al_2O_3$ as catalysts. When MgO/OMA was applied, it showed excellent performance in the plasma reactor using pulse-type power supply and the selectivity of $C_2$ chemicals was measured as 67%. The effects of metal oxide type, textural property of support, alumina phase and power supply type on catalytic performance were investigated especially in terms of $C_2$ chemical formation. BET (Brunauer, Emmett, Teller), X-ray diffraction, transmission electron microscope and thermogravimetric analysis were used to investigate the characterization of the catalyst before and after the reaction.

• Clinical and Experimental Reproductive Medicine
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• v.44 no.3
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• pp.141-145
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• 2017

Objective: Delaying embryo transfer (ET) enables us to select among the embryos available for transfer and is associated with positive effects on implantation and pregnancy outcomes. However, the optimal day for ET of human cleavage-stage embryos remains controversial. Methods: A retrospective study of 3,124 in vitro fertilization/intracytoplasmic sperm injection cycles (2,440 patients) was conducted. We compared the effects of day 2 and 3 ET on rates of implantation and pregnancy outcomes between young maternal age (YMA; < 38 years old, n = 2,295) and old maternal age (OMA; ${\geq}38years\;old$, n = 829) patient groups. Results: The YMA and OMA groups did not differ in terms of patient characteristics except for the proportion of unexplained factor infertility, which was significantly greater in the OMA group, and the proportion of arrested embryos, which was significantly greater in the YMA group. However, the biochemical pregnancy, clinical pregnancy, ongoing pregnancy, abortion, and implantation rates per cycle were not significantly different between day 2 and 3 ET in the YMA group or the OMA group. Conclusion: We suggest that offering patients the opportunity to decide which day would be suitable for ET could be part of a patient-friendly protocol that takes into consideration an infertile woman's circumstances and work schedule by allowing ET to be performed on day 2 instead of the traditional transfer on day 3.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.2
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• pp.45-54
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• 2006

As widespread of using digital documents in various fields, control the usage of digital document is needed. So, Digital Rights Management(DRM) will become a key component of digital document system, but absence of proper digital document DRM system, there is a real risk to lose important information when a hacker achieved intrusion in important system. This paper designs and implements digital document DRM system based on OMA(Open Mobile Alliance) DRM model and OpenOffice. We considered being a digital document DRM system to contain appropriate solution of security and document compatibility.

• Korean Institute of Interior Design Journal
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• v.14 no.3 s.50
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• pp.73-83
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• 2005

Recently, by the expansion of Industrial Capitalism and the development of Information Technology, the qualify of humans' life came to have various aspects. In this era of variety, among all the different attempts Rem Koolhaas(OMA)'s architectures attract attention for their architecture's new point of view in architectural design. On the basis of the objective fact in the modern world, as a construction which expresses the language naturally, and a democratic architecture of a faithful part for the whole, these kinds of approach shows the similarity and the properties of Neue Sachlichkeit which has appeared in the colloquy and photographs in Germany at the end of the 20th century in the past. The main purpose of this study is to recognize the understanding and development of Neue Sachlichkeit's properties in architecutre - the Neue Sachlichkeit's influence on the architecture from elementerism, Constructivsit International, ABC Group and Holland's 'the De 8 and Opbouw's' architecture's move to the Holland's architecture - in colloquy and photographs from 1910 to 1930 which had the similar aspect and chronological situation of the modern world.

• Structural Monitoring and Maintenance
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• v.6 no.1
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• pp.33-46
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• 2019

In present study, Operational Modal Analysis (OMA) was employed to carry out the dynamic and vibration analysis of the threshing unit of the combine harvester thresher as a mechanical component. The main study is to find the causes of vibration and to decrease it to enhance the lifetime and efficiency of the threshing unit. By utilizing OMA, structural modal parameters such as mode shapes, natural frequencies, and damping ratio was calculated. The combine harvester was excited by engine to vibrate different parts and accelerometer sensor collected acceleration signals at different speeds, and OMA was utilized by nonparametric and frequency analysis methods to obtain modal parameters while vibrating in real working conditions. Afterwards, finite element model was designed from the thresher and updated using the data obtained from the modal analysis. Using the conducted analyses, it was specified that proximity of the thresher pass frequency to one of the natural frequencies (16.64 Hz) was the most important effect of vibration in the thresher. Modification process of the structure was carried out by increasing mass required for changing the natural frequency location of the first mode to 12.4 Hz in order to reduce resonance and vibration of the thresher.

• Journal of Korea Society of Industrial Information Systems
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• v.15 no.5
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• pp.137-148
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• 2010

In this paper, a mobile office support. system which consists of mobile devices and servers is proposed. An efficient mobile office support system is required to study since the existing mobile office support systems may face the serious problems such as an absence of interoperability, difficulties of data synchronization and device management in the near future, especially when a company has a large number of outdoor service employees. In this paper, a mobile office support system requirements for a company with a large number of outdoor service employees is proposed. And then, the methods to satisfy the requirements using a remote data synchronization and a remote device management technologies are proposed. The mobile office support system proposed in this paper synchronizes remotely a large number of various mobile devices of employees with centralized servers located in the company. In addition, it manages the mobile devices remotely for the employees. This paper proposes a mobile office support system based on OMA(Open Mobile Alliance) DS(Data Synchronization) and DM(Device Management) protocols. As OMA DS and DM protocols are de facto international standards, the interoperability between the mobile office support systems can be guaranteed.

• Korean Architects
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• s.552
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• pp.22-23
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• 2015

• Proceedings of the Korean Vacuum Society Conference
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• 1995.02a
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• pp.80-80
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• 1995