• Journal of the Korea Society for Simulation
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• v.25 no.1
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• pp.1-9
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• 2016

This study focuses on the air to air missile control fin planform optimization for the minimizing hinge moment with the considering phenomena of fluid and structure simultaneously. The fluid-structure interaction method is applied for the fluid and structure phenomena simulation of the control fins. A transient-loosely coupled method is used for the fluid-structure interaction simulation because it is suited for using each fluid and structure dedicated simulation software. Searching global optimization point is required many re-calculation therefore in this study, a mathematical model is applied for rapidly calculation. The face centered central composite method is used for generating design points and the 2nd polynomial response surface is sued for generating mathematical model. Global optimization is performed by using the generic algorithm. An objective function is the minimizing travel distance of the center of pressure between Mach 0.7 and 2.0 condition. Finally, the objective function of optimized planform is reduced 7.5% than the baseline planform with satisfying constrained conditions.

• Journal of Pharmaceutical Investigation
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• v.32 no.1
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• pp.27-33
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• 2002

A self-microemulsifying drug delivery system(SMEDDS) composed of Cremophor $EL^{\circledR},\;Labrasol^{circledR}$, and Lauroglycol $FCC^{circledR}$ was prepared for the enhancement of solubility, dissolution rate and bioavailability of ibuprofen(IBP), which is water-insoluble but soluble in oils and surfactants. Phase diagram with various regions including microemulsion area was depicted. The SMEDDS was encapsulated in soft gelatin capsules and their dissolution characteristics in various media were observed in comparison to the generic products commercially available in the market. Soft capsules of SMEDDS formulation showed better dissolution profiles, especially in acidic condition, than the others. For the period of 1 hr dissolution in pH 1.2 medium, it reached over 70% dissolution from soft capsules, compared to less than 40% dissolution from commercial reference tablets. On the other hand, in vivo pharmacokinetic parameters were obtained after oral administrations of different IBP preparations to Sprague Dawley rats. SMEDDS formulation showed higher $C_{max}$ and greater $AUC_{0-5hr}$ than the suspension of reference tablet or IBP powder. Therefore, it is possible to conclude that a newly developed soft capsules employing SMEDDS provides an alternative preparation to improve oral bioavailability of IBP.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.93-96
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• 2011

A genetic algorithm (GA) has been employed to optimize the major design variables of the liquid rocket engine. Mass flow rate to the main thrust chamber, mass flow rate to the gas generator and chamber pressure have been selected as design variables. The target engine is the open gas generator cycle using the LO2/RP-1 propellant. The objective function of design optimization is to maximize the specific impulse with condition of energy balance between the pump and the turbine. The properties of the combustion chamber have been obtained from CEA2. Pump & turbine efficiencies and properties of the gas generator have been modeled mathematically from reference data. The result shows 3~4% errors for the specific impulse and 2~6% errors for the pump power of the gas generator cycle compared to references.

• Nuclear Engineering and Technology
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• v.54 no.4
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• pp.1421-1430
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• 2022

The computation of the solid angle and the detector efficiency is considering to be one of the most important factors during the measuring process for the radioactivity, especially the cylindrical γ-ray NaI(Tl) detectors nowadays have applications in several fields such as industry, hazardous for health, the gamma-ray radiation detectors grow to be the main essential instruments in radiation protection sector. In the present work, a generic numerical simulation method (NSM) for calculating the efficiency of the γ-ray spectrometry setup is established. The formulas are suitable for any type of source-to-detector shape and can be valuable to determine the full-energy peak and the total efficiencies and P/T ratio of cylindrical γ-ray NaI(Tl) detector setup concerning the truncated conical radioactive source. This methodology is based on estimate the path length of γ-ray radiation inside the detector active medium, inside the source itself, and the self-attenuation correction factors, which typically use to correct the sample attenuation of the original geometry source. The calculations can be completed in general by using extra reasonable and complicate analytical and numerical techniques than the standard models; especially the effective solid angle, and the detector efficiency have to be calculated in case of the truncated conical radioactive source studied condition. Moreover, the (NSM) can be used for the straight calculations of the γ-ray detector efficiency after the computation of improvement that need in the case of γ-γ coincidence summing (CS). The (NSM) confirmation of the development created by the efficiency transfer method has been achieved by comparing the results of the measuring truncated conical radioactive source with certified nuclide activities with the γ-ray NaI(Tl) detector, and a good agreement was obtained after corrections of (CS). The methodology can be unlimited to find the theoretical efficiencies and modifications equivalent to any geometry by essential sufficiently the physical selective considered situation.

• Journal of Korean Society of Steel Construction
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• v.28 no.5
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• pp.373-382
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• 2016

Painting or thermally sprayed metal coating is often used in corrosion protection of steel structures. In recently, duplex coating system which combines thermally sprayed metals with paint is selected as a new generic type of coatings on steel structures under the highly corrosive environments. In this study, the structural steel specimens were surface treated, thermally sprayed with zinc, zinc-15%aluminum alloy, aluminum and aluminum-5%magnesium alloy, and finally sealing or painted with acrylic urethane. And as a reference specimens, steel specimens were painted with acrylic urethane after surface treatment. Circular defects with 1.0, 3.0 and 5.0 mm in diameters and line defect with 2.0 mm width, which reach the steel substrate were created on all specimens. The specimens were exposed into an environmental testing chamber controlled by the ISO 20340, which is a laboratory cyclic accelerated exposure test condition of spraying/UV/low temperature, for up to 175 days. Based on the corrosion tests, corrosion deterioration from the initial defects were evaluated and weathering performance of the specimens are compared.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.10
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• pp.185-190
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• 2007

In this paper, minimum sampling rates and method of nonlinear characterization were suggested for low power, quasi-memoryless PAs. So far, the Nyquist rate of the input signal has been used for nonlinear PA modeling, and it is burdening Analog-to-digital converters for wideband signals. This paper shows that the input Nyquist rate sampling is not a necessary condition for successful modeling of quasi-memoryless PAs. Since this sampling requirement relives the bandwidth requirements for Analog-to-digital converters (ADCs) for feedback paths in digital pre-distortion systems, relatively low-cost ADcs can be used to identify nonlinear PAs for wideband signal transmission, even at severe aliasing conditions. Simulation results show that a generic memoryless nonlinear RF power amplifier with AMAM and AMPM distortion can be successfully identified at any sampling rates. Measurement results show the modeling error variation is less than 0.8dB over any sampling rates.

• The Korean Journal of Mycology
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• v.27 no.3 s.90
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• pp.191-197
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• 1999

The phylogenetic position of Gliocladium and its related taxa were investigated, using the neighbor-joining method of the sequences from internal transcribed spacers (ITS1 and ITS2) and 5.8S ribosomal DNA (rDNA). It was focused especially on the generic concept by comparing with the related genera such as Trichoderma, Hypocrea, Verticillium, Penicillium and Talaromyces. Gliocladium species and its related genus were divided into three groups by the phylogenetic analysis using the neighbor-joining method. The first group includes Penicillium-like strains such as Penicillium, Tararomyces, Verticillium and one species of Gliocladium (G. cibotii JCM 9203 and JCM 9206). Especially, Gliocladium cibotii JCM 9203 is thought to be the similar species with Verticillium bulbillosum JCM 9214. Between these two species, Gliocladium cibotii and Verticillium bulbillosum, the intraspecies concept needs to examined with culture condition. and morphological properties. The second group includes two species Verticillium, Verticillium tricorpus and Verticillium albo-atrum which extracted from the GenBank database in NCBI (National Center for Biotechnology Information). Trichoderma-like strains, such as Trichoderma, Hypocrea and several species of Gliocladium are included in the third group. Also, Gliocladium penicillioides IFO 5869 and Gliocladium catenulatum ATCC 10523 formed the subgroup of Trichoderma-like strains. The species of Gliocladium were dispersed in Trichoderma-like and Penicillinum-like group, and only one species of Gliocladium cihotii used in our study was located in Penicillium-like genus group. The species of Verticillium appeared in all three groups and the species of Trichoderma formed the monophylogeny with Hypocrea (telemorph). Also, Gliocladium virens was grouped with Trichoderma harzianum with a high bootstrap value, supporting that Gliocladium virens is to be placed in Trichoderma. The results suggest that Gliocladium is polyphyletic, and is more Trichoderma-like than Penicillium-like.

• Smart Structures and Systems
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• v.6 no.5_6
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• pp.481-504
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• 2010

Wireless smart sensor networks (WSSNs) have been proposed by a number of researchers to evaluate the current condition of civil infrastructure, offering improved understanding of dynamic response through dense instrumentation. As focus moves from laboratory testing to full-scale implementation, the need for multi-hop communication to address issues associated with the large size of civil infrastructure and their limited radio power has become apparent. Multi-hop communication protocols allow sensors to cooperate to reliably deliver data between nodes outside of direct communication range. However, application specific requirements, such as high sampling rates, vast amounts of data to be collected, precise internodal synchronization, and reliable communication, are quite challenging to achieve with generic multi-hop communication protocols. This paper proposes two complementary reliable multi-hop communication solutions for monitoring of civil infrastructure. In the first approach, termed herein General Purpose Multi-hop (GPMH), the wide variety of communication patterns involved in structural health monitoring, particularly in decentralized implementations, are acknowledged to develop a flexible and adaptable any-to-any communication protocol. In the second approach, termed herein Single-Sink Multi-hop (SSMH), an efficient many-to-one protocol utilizing all available RF channels is designed to minimize the time required to collect the large amounts of data generated by dense arrays of sensor nodes. Both protocols adopt the Ad-hoc On-demand Distance Vector (AODV) routing protocol, which provides any-to-any routing and multi-cast capability, and supports a broad range of communication patterns. The proposed implementations refine the routing metric by considering the stability of links, exclude functionality unnecessary in mostly-static WSSNs, and integrate a reliable communication layer with the AODV protocol. These customizations have resulted in robust realizations of multi-hop reliable communication that meet the demands of structural health monitoring.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.6
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• pp.457-467
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• 2018

Currently, the regulation and rules for public surveying and the UCPs (Unified Control Points) adapts those of the triangulated traverse surveying. In addition, such regulations do not take account of the unique characteristics of GNSS (Global Navigation Satellite System) surveying, thus there are difficulties in field work and data processing afterwards. A detailed procesure of GNSS processing has not yet been described either, and the verification of accuracy does not follow the generic standards. In order to propose an appropriate procedure for field surveys, we processed a short session (30 minutes) based on the scenarios similar to actual situations. The reference network in Seoul was used to process the same data span for 3 days. The temporal variation during the day was evaluated as well. We analyzed the accuracy of the estimated coordinates depending on the parameterization of tropospheric delay, which was compared with the 24-hr static processing results. Estimating the tropospheric delay is advantageous for the accuracy and stability of the coordinates, resulting in about 5 mm and 10 mm of RMSE (Root Mean Squared Error) for horizontal and vertical components, respectively. Based on the test results, we propose a procedure to estimate the daily solution and then combine them to estimate the final solution by applying the minimum constraints (no-net-translation condition). It is necessary to develop a web-based processing system using a high-end softwares. Additionally, it is also required to standardize the ID of the public control points and the UCPs for the automatic GNSS processing.

• Journal of Yeungnam Medical Science
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• v.2 no.1
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• pp.95-102
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• 1985

This report offers descriptive data about the drugs utilized in out patient department (OPD) of Yeungnam University Hospital (YUH) in the period of march to august in 1985. The data in this report were produced by the computerized totalization of the number of mentions of individual drugs included in the prescriptions. The 100 drug entries that were most frequently recorded are listed in rank order. The listing is arbiturarily restricted to the drugs that were prescribed as single preparations, the drugs of basis of compound preparations and the drugs of adjuvent or corrective of compound preparations that have significant therapeutic effects either by generic names. And in addition, the listing also involves the compound preparations used in relatively large frequency, and the individual components of which have the unique pharmacological actions each other by proprietary names. And all routes of administrations were allowed. The 10 drugs most frequently named are diazepam, aluminum compounds, acetaminophen, isoniazid, metoclopramide, $polaramine^{(R)}$, carboxymethylcystem, ephedrine, codeine and caroverine in order. The 521,855 drug mentions listed as above are described by the chief therapeutic usage that each is intended to apply generally. The drugs which account the largest proportion of total mentions were those acting on the central nervous system (20.57%), including tranquilhzers and sedative hypnotics (11.71%), analgesic antipyretics (5.55%), antidepressants (2.15%) etc. Gastrointestinal drugs and smooth muscle preparations (18.64%) included antacids and anti-ulcer drugs (9.24%), antiemetics (3.57%), spasmolytics (3.14%) and others. Respiratory drugs (16.11%) included expectorants and cough preparations (10.99%) and bronchodilators (5.12%). Chemotherapeutic agents (15.12%) included the antiTbc drugs (7.09%) most frequently, and the penicillins (3.33%) accounted the largest proportion among the antibiotics. Cardiovascular drugs (5.64%) included cardiac drugs and coronary vasodilator (4.12%) and antihypertensives and vasodilators (1.06%). And anti-inflammatory drugs (4.33%), vitamins of single preparations (3.76%), hormones and their antagonists (3.29%), common cold preparations (3.12%), diuretics (2.81%), drugs supporting liver function (2.02%), drugs affecting autonomic nervous system(1.89%) including anti-glaucomas, atropine and cerebral vasodilators, antihistamine drugs (1.02%) and disinfectants (0.74%) were following in order. The data in this report were compared to those reported by H. Koch, et al. in United States (US), 1981 as "Drugs Most Frequently Used in Office Practice:National Ambulatory Medical Case Survey, 1981." Cardiovascular drugs prescribed in YUH were much less in proportion than in US (10.56%), but gastrointestinal drugs accounted the larger proportion than in US (3.72%). Expectorants and cough preparations in YUH also accounted the larger proportion than in US (2.74%). In conclusion, in the period of march to august, 1985, OPD of YUH prescribed the CNS drugs including diazepam most frequently, and gastrointestinal, repiratory and chemotherapeutic drugs in next orders. It is supposed that the eating habits of Koreans and a unique atmospheric condition in Taegu as a basin were some important factors that affected the proportions of drugs acting on gastrointestinal and respiratory tracts.