• Journal of IKEEE
• /
• v.8 no.1 s.14
• /
• pp.79-85
• /
• 2004

In this paper, Sub harmonic mixer using anti-parallel diode pair is designed for 5.8 GHz Wireless LAN. Conventional mixers mix LO with RF and obtain IF signal from the difference between LO and RF. As frequency increase, LO signal is required increasing LO power, better phase noise, stable LO. But, using APDP, the SHP mixer mix the harmonics of LO signal. Therefore, Sub harmonic mixer is advantage that necessary LO signal frequency was used to operate the 1/2. When LO power is 3 dBm, the conversion loss of manufactured SHP mixer is 12.83 dB. The isolation of LO/IF, 2LO/IF, RF/IF and LO/RF is 39.17 dB, 58 dB, 34 dB, 67.9 dB. And IIP3 is 8 dBm.

• Journal of the Microelectronics and Packaging Society
• /
• v.21 no.4
• /
• pp.133-137
• /
• 2014

As a preceding process for preparing several micrometer sized Ag-coated Cu flakes, ball milling of submicrometer-sized Cu particles synthesized through a wet chemical method was performed in order to convert the particles into flakes. To suppress oxidation and aggregation of the particles during ball milling, ethylene glycol and ethyl acetate were used as a medium and a surface modifying agent, respectively. Results obtained with different rotation speeds of a jar indicated that the rotation speed changes a rotating mode, and strikingly alters the final shapes and shape uniformity of Cu particles after milling. The diameter of zirconia ball was also confirmed. Although there was aggregates in the initial submicrometer-sized Cu particles, therefore, well-dispersed Cu flakes with a size of several micrometers were successfully prepared by ball milling through optimization of rotation speed, amount of ethyl acetate, and diameter of zirconia ball.

• Journal of Korea Multimedia Society
• /
• v.5 no.4
• /
• pp.393-398
• /
• 2002

The conventional bit allocation scheme for MPEG-1 audio encoding searches the subband with minimum MNR(mask-to-noise ratio) repetitively until its operation is completed, which occupies most of its total computational complexity. In this paper, as a computationally efficient approximation of it, we propose a new bit allocation scheme with a simple subband search and compare it with the existing schemes[1][2] in terms of the computational complexity and sound quality. For the performance comparison, we used the pop music signal contained in SQAM(sound quality assess material) CD from EBU. Simulation results show that the computational complexity of the proposed method is about 42% of that of the existing one in [1] and the sound quality difference in terms of MNR between the two schemes is within the 0.2 ㏈, for the case of using the layer II at the bit rate of 128 kbps.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.26 no.2
• /
• pp.124-131
• /
• 1989

This paper showed that the system reliability optimization problem with sereval failure modes at each subsystem can be treated as efficient computational algorithm proposed here. This algorithm was developed by considering a generalized upper bounding which always exists in constraints when the system reliability optimization problem may be reformulated as 0-1 integer programming problem. We demonstrated the optimal allocation of redundant units for system reliability by using the proposed algorithm. Our algorithm is superior to others in terms of number of iterations and variables used.

• Journal of Information Technology and Architecture
• /
• v.10 no.4
• /
• pp.467-478
• /
• 2013

The necessity of research for EA service and performance is surfacing while nation-level and individual agency level performances utilizing Government-wide EA information. In this study, performance model for EA service has been developed categorizing characteristic elements of EA as service. And weight differences between quality items that constitute performance model have been calculated using AHP analysis method. To achieve the stated, SERVQUAL applied performance model for EA service has been developed working through logical reasoning and a broad range of theoretical studies concerning EA service. Moreover, relative weight differences between quality items that constitute the model have been calculated. The results of weight analysis find that importance differences between quality items in order of significance are as follows: EA administrator > EA information > EA education > EA policy > EA operating system. This study, as the nation's first research to graft the public-sector EA service onto SERVQUAL Model that is capturing remarkable attention, has considerable practical and theoretical implications.

• Aerospace Engineering and Technology
• /
• v.9 no.1
• /
• pp.133-142
• /
• 2010

Propulsion system of launch vehicle is composed with subsystems as propellant tank, pressurization system, propellant fill/drain system, valve operating system, purge system and so on. Among others, pressurization system is the most important subsystem, because of the real-time control part for pressure control of propellant tank. Therefore, it is the subsystem that must be primarily considered on conceptual design process. In this paper, the data of the previously developed pressurization systems were collected and the optimum configuration was selected by analysis of advantage and disadvantage of the systems.

• Information Systems Review
• /
• v.22 no.1
• /
• pp.91-111
• /
• 2020

E-book markets are currently moving through a period of disequilibrium as new pricing structures (i.e., flat-fee subscriptions) are rapidly embraced by major vendors. On the basis of a novel dataset, we investigate how the availability of "all-you-can-read" pricing programs influences consumers' tariff choice and contract renewal behaviors. Consistent with the rational choice framework, the findings suggest that most e-book consumers significantly gain from subscription-based tariffs. Power readers prefer flat-fee subscriptions, and those that have economically benefited renew their subscription. However, we also find some other intriguing results. Among the three subscription designs examined, the 1-week plan affords consumers more economic benefits than do 1-day or 1-month programs. Finally, iOS users are more inclined to select subscription models than are Android users because of the absence of in-app purchase functionalities for the former. The unavailability of in-app purchase affects tariff choices and transaction patterns as it increases transaction costs.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.18 no.1
• /
• pp.85-90
• /
• 2014

To develop liquid propulsion engine, the development of combustion chamber must be preceded. For performance validation of the combustion chamber, the designed and manufactured combustion chamber should be tested in combustion chamber test facility (CCTF). The CCTF is the test facility to develop the combustor of rocket engine, which uses liquid oxygen as a oxidizer and kerosene as a fuel. Present paper introduces the detailed design results of compressed gas supply system of CCTF, which is planned to be installed at Naro Space Center.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.12 no.2
• /
• pp.73-79
• /
• 2002

The polyol process which applies to cobalt, nickel. copper and precious metals is a interesting and unexpected example of such a method for preparing uniform metal powders. The reaction proceeds via dissolution, and the polyol acts simultaneously as a solvent, a reducing agent, and to some extent a protective agent. Submicrometer uniform cobalt particles can be obtained by seeding the reactive medium ($AgNO_3$) to achieve a complete substitution of homogeneous by heterogeneous nucleation. By varying the number of nuclei it is possible to control to some extent the average particle size in the submicrometer (0.5$\mu$m) range.

• Cartoon and Animation Studies
• /
• s.41
• /
• pp.553-578
• /
• 2015

The Korean society was forcefully merged with the invasion of Japan in 20th century, and traditional culture of Korea was damaged severely by colonization from Japan. After liberation, Korean society experienced drastic social change with Korean War, and industrial economy and democratic system developed as modernization and democratization occurred. However, Korean traditional culture dissolved more severely as Korean society developed industrial economy and democracy. As criticism of existing Western center of society and the emphasis of cultural identity of non-western regions and third-world, world society preferred exchange of culture of diverse nations and people with each other in advent of postmodernism thoughts in mid-late 20th century. If the cultural identity of Korea was dissolving meanwhile, it was needed to be recovered again. Despite the research in Korean history, language, art, architecture was performed to recover cultural identity of Korea, it did not go in-depth with Korean mythology, for Korean mythology is considered as superstition or savage. Mythology shows subconscious group psychology of people who live in certain specific region. Studying Korean mythology is one of the ways to rediscover cultural identity of Korea. In order for Korean mythology to be known to many people, its stories should be told by media. There were movies, plays, drama, and novels produced based on existing Korean mythology as introduction, then these mythical stories are appear in subculture contents such as recent comics, animation, webtoon, games, and light novels. Then population of game players and webtoon readers increased as dissemination of PC and smart phones, and increasing market scale of subculture contents increased a population of consumers of comics, animation, and light novel. Consumers of sub-culture contents were interested as many of these contents were created, base on Korean mythology. Therefore, this paper is written as research on Korean mythology and its signification in sub-cultural contents which were produced base on Korean mythology.