• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.2
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• pp.144-148
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• 2004

Generally a ship in a port or canal is guided by tugboat(s), while the ship engine(s) and steering mechanism idle. The shortcomings of this method are insufficient in course keeping ability, danger of collision with waterside structures, time-consuming preparation for tugging, as well as the need to maintain tugboats. A new technology for ship guiding, based on the physical principle of interaction of a solid body with aerated liquids has been developed [1]. Model tests were carried out for the verification of system at slow speed by engine operating conditions and with an idle steering. The developed device has been proved to keep the ship on course safely.

• Journal of Navigation and Port Research
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• v.34 no.7
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• pp.525-532
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• 2010

Mobile Harbor (MH) is a new transportation platform that can load and unload containers onto and from very large container ships at sea. It could navigate near harbors where several vessels run, or it could navigate through very narrow channels. In the conceptual design phase when the candidate design changes frequently according to the various performance requirements, it is very expensive and time-consuming to carry out model tests using a large model in a large towing tank and a free-running model test in a large maneuvering basin. In this paper, a new Planar Motion Mechanism(PMM) test in a Circulating Water Channel (CWC) was conducted in order to determine the hydrodynamic coefficients of the MH. To do this, PMM devices including three-component load cells and inertia tare device were designed and manufactured, and various tests of the MH such as static drift test, pure sway test, pure yaw test, and drift-and-yaw combined test were carried out. Using those coefficients, course-keeping stability was analyzed. In addition, the PMM tests results carried out for the same KCS (KRISO container ship) were compared with our results in order to confirm the test validity.

• Journal of Korean Medical classics
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• v.25 no.4
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• pp.57-63
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• 2012

Objective & Method : We investigated the identity of tri-energizer, which was originally described in Huang Di Nei Jing and claimed by traditional scholars, and drew the following conclusions. Result & Conclusion : According to Huang Di Nei Jing tri-energizer is one of the six hollow-organs and is called hollow organs for digestion and elimination, water guffer organ, or solitary hollow organ. It is believed that tri-energizer is regarded as the existing entity based on following several different sources; it functions as the course of channels, regulates wind and link and physiological function-especially intrinsic function of upper, middle, lower internal organs. It also controls syndromes and dysfunction of an illness, the surface of the body, and the cracked surface of the skin. Finally, bold and timidity depend on the tri-energizer. Experts determined the true nature of tri-energizer types. Experts include: Yu Tuan from the Ming dynasty, Tang Jong Hai and Ye Lin from the Qing dynasty, and Zhang Xi Chun from the Zhunghua Minguo period. These experts' claims are based on shape and forms of tri-energizer. Our examinations of anatomical and physiological basis on tri-energizers showed that, in a narrow sense, tri-energizer indicates visceral and parietal peritoneum and omentum surrounding the internal organs, and in a broad sense, indicates the overall membrane wrapping around the whole internal organs including five visceral organs and six hollow organs.

• ETRI Journal
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• v.34 no.1
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• pp.9-16
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• 2012

Precoding in the multiple-input multiple-output orthogonal frequency division multiplexing system is investigated. In conventional wideband precoding (WBP), only one precoder, obtained from the decomposition of the subcarrier independent channel matrix, is used for all subcarriers. With an investigation of the relationship between the subcarrier independent channel matrix and the temporal/frequency channels, an improved WBP scheme is proposed for practical scenarios in which a part of subcarriers are allocated to a user. The improved WBP scheme is a generalized scheme of which narrow-band precoding and conventional WBP schemes are special modes. Simulation results demonstrate that the improved WBP scheme almost achieves the optimum performance of a single precoder and outperforms the conventional WBP scheme in terms of the bit error ratio and ergodic capacity with slight complexity increase. The largest advantage of the improved WBP scheme on signal-to-noise ratio in simulation results is over 2.1 dB.

• Journal of Haehwa Medicine
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• v.14 no.2
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• pp.197-204
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• 2005

The general conception of morbid leukorrhea is confused in its clinical application. Therefore, this studt was conducted to examine this conception based on terminology of morbid leukorrhea centering around historical literatures. The result of this study is summarized as follows. 1. Morbid leukorrhea had been considered as a disease of all women before Shou period, and then it was subdivided. 2. It was shown that morbid leukorrhea, spontaneous emission, whitish and turbid urine, and dysentery were treated by the same mwthod because their exposed regions and conditions were very similar. For this reason, it was confused to define terminology of morbid leukorrhea. 3. It was also shown that there existed both terminologies of morbid leukoeehea, as its conception in a board sense, even in Sikryoboncho. After that, however, only terminology of morbid leukorrhea was used. Currently, these terminologies tended to be used together. 4. In case of its conception in a board sense, morbid leukorrhea means all gynecological disease and syndrome of the lower burner which cause diseases in the belt channel 5. In case of its conceptio of a narrow sense, morbid leukorrhea implies disease in the front middle regions of channels and collacterals, which has been recntly considered as secretions of women.

• Journal of the Korean Ceramic Society
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• v.34 no.4
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• pp.343-350
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• 1997

To fabricate the ceramic/metal(SiC/ Al alloy) composite, SiC preform was prepared by Pressureless Powder Packing Forming Method and 6061 Al alloy was infiltrated into the preform. Uniform compact having an average pore size of 10 ${\mu}{\textrm}{m}$ and narrow pore size distribution was prepared. Phenolic resin solution(40 wt%) was penetrated into the SiC compact, and then the compact was preheated at the temperature of 120$0^{\circ}C$. The pore size distribution and the microstructure of the preform were not changed by preheating. An uniform microstructure without any crack in the preform was obtained in SiC-Al alloy composite. The infiltration of 6061. Al alloy into the preform began at the temperature of 130$0^{\circ}C$ and the amount of infiltration increased in proportion to the infiltration temperature and the soaking time. The increasement rate of the infiltration amount decreased after 3 h. As a result of the infiltration at 140$0^{\circ}C$ for 4 h, Al alloy was well distributed in the interparticle channels and the relative density of the composite was above 98%. The strength and the fracture toughness of the composite were 303 MPa and 21.65 MPam1/2, respectively.

• New & Renewable Energy
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• v.8 no.2
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• pp.6-13
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• 2012

Due to global warming, the need to secure an alternative resource has become more important nationally. Having very strong current on the west coast with up to 10 m tidal range, there are many suitable site for the application of TCP (Tidal Current Power) in Korea. On the south west regions between many islands that create strong current in the narrow channels. The rotor is one of the essential components which can convert tidal current energy into rotational energy to generate electricity. The design optimization of rotor is very important to maximize the power production. The performance of rotor can be determined by various parameters including number of blades, shape, sectional size, diameters and etc. This paper introduces the multi-layer vertical axis tidal current power system which can be applied to offshore jetties and piers effectively. Various cases of VAT turbine were designed. Specifically, the number of blades and turbine shape are changed in several cases. Also, performance analysis was carried out by CFD.

• Proceedings of the Korean Geotechical Society Conference
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• 1992.12a
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• pp.33-66
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• 1992

Recently, waste landfills built on seashores have been increased because of the easy availability of broad area near the urban communities. To evaluate the performance of the marine clay landfill liner numerical contaminant transport analyses are performed by selecting the typical section of a waste landfill built on seashores and using hydraulic conductivity data obtained from the site. Also, the laboratory electrical resistivity test and the in-situ corrosion test are performed in order to analyze the influence of the soil and leachates composing the landfills on the construct ion materials. From the results of contaminant transport analyses, it is shown that the leachates can be migrated faster through narrow pervious channels than the wide homogeneous pervious tedium and the importance of good quality barriers to prevent the contaminant migration is recognized. In the laboratory electrical resistivity test all the earth materials except the cover soils saturated with distilled water have small resistivities, which shows a high potential of corrosivity of soils composing landfills. However, the degree of corrosion of specimens buried in the landfills was not so severe except the zinc and carbon steel specimens. This apparently conflict results present the necessity of the investigation of other major factors and the long term in-situ corrosion test.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.8A
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• pp.836-846
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• 2007

Wireless Communication is playing a key role in implementing the ubiquitous society. However, due to the increasing wireless and mobile devices occupying the spectrum, the frequency resources are believed to become more and more limited. In order to deal with the problem, coexistence is considered to be a effective method to improve the efficiency of spectrum utilization between several different systems. Here, we utilize the UWB system to realize the coexistence, because it is an ultra wide band system which can co-exist with other narrow band systems. On the other hand, Cognitive Radio technology is an intelligent technology which can sense the spectrum environment and adaptively adjust the parameters for wireless transmission. In this paper, by using Cognitive UWB, the spectrum efficiency of the transmission channels is largely improved; Furthermore, the interference to other systems can be effectively avoided.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.4
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• pp.534-543
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• 2000

In this paper, when the current optical communication system is used for the DWDM. The FBG filter for the DWDN is able to reduce the interferences between the adjacent channels. In this paper, therefore, we find the relection spectrums for the three types of induced index changes, that is, uniform, Gaussian apodized, and raised-cosine apodized. From the obtained result in this paper, we can see that uniform FBG does not fit, and that the smaller the maximum induced index change $\sigma$ is and the larger the value of parameter C in the raised-cosine apodized FBG and G in the Gaussian apodized FBG are the fitter they are on the narrow filter for DWDM.