• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.337-339
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• 2005

By definition of RFC 2018, each segments block of data queued at the data receiver is defined in the SACK option by two 32-bit unsigned integers in network byte order. Since TCP Options field has a 40-byte maximum length, when error bursts occur we note that the limitation of maximum available option space may not be sufficient to report all blocks present in the receiver's queue and lead to unnecessarily force the TCP sender to retransmit packets that have actually been received but not carried related information in SACK option field. For overcoming this restriction, in this paper, a new solution is designed to further improve the performance of TCP SACK and prevent those unwanted retransmissions. Simulation result shows that the implementation of our proposal is effective.

• Structural Engineering and Mechanics
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• v.72 no.4
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• pp.503-512
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• 2019

The construction of segmental precast concrete bridge is an increase due to its superior performance and economic advantages. This type of bridge is appropriate for spans within 30 to 150 m (100 to 500 ft), known as mega-projects and the design optimization would lead to considerable economic benefits. A box-girder cross section superstructure of balanced cantilever construction method is assessed here. The depth of cross section, (variable along the span linearly), bottom flange thickness, and the count of strands are considered as design variables. The optimum design is characterized by geometry, serviceability, ductility, and ultimate limit states specified by AASHTO. Genetic algorithm (GA) is applied in two fronts: as to the saving in construction cost 8% and as to concrete volume 6%. The sensitivity analysis is run by considering different parameters like span/depth ratio, relation between superstructure cost, span length and concrete compressive strength.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.92-98
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• 2018

The effect of surfactants with different chain length on the drying dynamics of nanosized dispersion droplets and on the final morphology of the grains formed after water evaporation is investigated experimentally. An acoustic levitator was used to examine the drying dynamics of single droplets and SEM imaging was used to characterise the morphology of the final dried grains. Results show that the drying of drops with high molecular weight surfactants leads to more irregular grains and that the grain morphology is related to surface tension driven instability of the evaporating droplets which may lead to formation of hollow dried grains.

• Steel and Composite Structures
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• v.39 no.1
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• pp.35-50
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• 2021

Eccentrically braced frames (EBFs) are utilized as a lateral resisting system in high seismic zones. Links are the primary source of energy dissipation and they are exposed to high deformation, which may lead to buckling. Web stiffeners were introduced to prevent buckling of shear link. AISC 341 provides the required vertical stiffeners for a shear link. In this study, different stiffener configurations were examined. The main objective is to improve the behavior of short links using different stiffener configurations. Pursuant to this goal, a comprehensive numerical study is conducted using ABAQUS. Shear links with different stiffener configurations were subjected to cyclic loading using loading protocol mandated by AISC 341. The results are compared in terms of energy dissipation and shear capacities and rupture index. The proposed stiffener configurations were further verified with different link length ratios, I-shapes and thickness of stiffener. Based on the results, the stiffener configuration with two vertical and two diagonal stiffeners perpendicular to each other is recommended. The proposed stiffener configuration can increase the shear capacity, energy dissipation capacity and the ratio of energy/weight up to 27%, 38% and 30%, respectively. Detailing of the proposed stiffener configuration is presented.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.7 no.1
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• pp.53-76
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• 1979

During cosmetic treatments, SURFACTANTS penetrate into KERATINOUS TISSUES (hair, skin and nails). Whereas some of these surfactant molecules migrate to the vital tissues, a considerable fraction remains bound to the keratin. The extent of binding depends both on the nature of the head group and the length of the hydrophobic tail of the detergent molecules. In addition to entering the amorphous region of the keratin, some of the detergents also penetrate into the crystalline microfibrils and change their structures affecting their tensile properties. Owing to an uneven distribution of detergent molecules in the tissues, an anisotropy of the elastic moduli will occur, resulting in considerable internal stresses which, in rum, might lead to a deterioration of hair, skin and nails. The chemical behavior of keratins is also influenced by the presence of absorbed detergent in their structures. Depending on the detergents and the conditions, these effects can be either protective or detrimental. The deposition of detergent molecules into keratin can be enhanced or diminished by the inclusion of appropriate ingredients into the product formulae.

• Journal of Digital Convergence
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• v.10 no.3
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• pp.233-240
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• 2012

This study aimed to clarify any factors that may have effect on the appropriateness of hospital admission and hospitalization with the intention of facilitating more efficient occupancy of hospital beds and better medical services in the aspect of their quality, minimizing unnecessary occupancy of beds, and ultimately helping patients requiring acute treatments to use immediately hospitals. This paper selected 154 Stroke patients who left neurology department of one general hospital from March, 1, 2006 to September, 31, 2010 as targets to meet the rate according to medical care security and to see the trend of recent 4 years. As study method, this paper analized medical treatment record with AEP to evaluate the appropriateness of hospital admission and stay and the collected data was computerized through SPSS 12.0. Based upon the results above, the conclusion was drawn that the higher appropriateness of hospital admission and the shorter length of hospital stay will lead to the higher appropriateness of hospitalization. In other words, it is required to provide hospitalized patients with all kinds of behaviors including medical treatments and nursing care service, management of pharmaceuticals, tests, rehabilitation and symptoms, as well as instructions and information for patients. Meanwhile, as it was found that the length of hospital stay may affect the appropriateness of hospitalization, the longer length of hospital stay may result in reduced bed turnover rate. In this light, it is necessary to organize a task force team responsible for evaluation and control of the appropriateness of hospitalization and hospital stay length to improve the quality of medical service in a medical center, so that patients can leave the center timely. Ultimately, governmental supports such as expansion of long-term care facilities will reduce the necessary length of hospital stay so that patients with stroke can receive rehabilitative treatments and long-term care service shortly after completion of acute treatments.

• Journal of the Korea Concrete Institute
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• v.22 no.5
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• pp.675-684
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• 2010

The reinforced concrete members are designed to fail in flexural to lead ductile fracture. In the building structures, the failure is typically imposed on beams to prevent damages in columns. However, progression of plastic collapse mechanism may ultimately develop, a plastic hinge at the bottem end of the first floor column, which then can be subjected to shear or bond finally due to large axial force and small shear span-to-depth ratio. In this study, 10 RC column specimens failed in shear after flexural yielding was investigated to determine the factors affecting the plastic hinge length. The findings of this study showed that the most effective factor affecting the plastic hinge length was an axial force. As an axial force increase, an axial strain and a ductility ratio were decreased obviously. The test also shows the observed plastic hinge length was about 0.8~1.2d and the this result has difference compared with forward research.

• The Journal of Korean Society for Radiation Therapy
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• v.34
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• pp.61-72
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• 2022

Purpose: Conventional CBCT(Cone-beam Computed-tomography) caused an error in the target volume due to organ movement in the area affected by respiratory movement. The purpose of this paper is to evaluate the usefulness of accuracy and time spent using the Gated CBCT function, which reduces errors when performing RGRT(respiratory gated radiation therapy), and to examine the appropriateness of phase. Materials and methods: To evaluate the usefulness of Gated CBCT, the QUASAR^TM respiratory motion phantom was used in the Truebeam STx^TM. Using lead marker inserts, Gated CBCT was scaned 5 times for every 20~80% phase, 30~70% phase, and 40~60% phase to measure the blurring length of the lead marker, and the distance the lead marker moves from the top phase to the end of the phase was measured 5 times. Using Cedar Solid Tumor Inserts, 4DCT was scanned for every phase, 20-80%, 30-70%, and 40-60%, and the target volume was contoured and the length was measured five times in the axial direction (S-I direction). Result: In Gated CBCT scaned using lead marker inserts, the axial moving distance of the lead marker on average was measured to be 4.46cm in the full phase, 3.11cm in the 20-80% phase, 1.94cm in the 30-70% phase, 0.90cm in the 40-60% phase. In Fluoroscopy, the axial moving distance of the lead marker on average was 4.38cm and the distance on average from the top phase to the beam off phase was 3.342cm in the 20-80% phase, 3.342cm in the 30-70% phase, and 0.84cm in the 40-60% phase. Comparing the results, the difference in the full phase was 0.08cm, the 20~80% phase was 0.23cm, the 30~70% phase was 0.10cm, and the 40~60% phase was 0.07cm. The axial lengths of ITV(Internal Target Volume) and PTV(Planning Target Volume) contoured by 4DCT taken using cedar solid tumor inserts were measured to be 6.40cm and 7.40cm in the full phase, 4.96cm and 5.96cm in the 20~80% phase, 4.42cm and 5.42cm in the 30~70% phase, and 2.95cm and 3.95cm in the 40~60% phase. In the Gated CBCT, the axial lengths on average was measured to be 6.35 cm in the full phase, 5.25 cm in the 20-80% phase, 4.04 cm in the 30-70% phase, and 3.08 cm in the 40-60% phase. Comparing the results, it was confirmed that the error was within ±8.5% of ITV Conclusion: Conventional CBCT had a problem that errors occurred due to organ movement in areas affected by respiratory movement, but through this study, obtained an image similar to the target volume of the setting phase using Gated CBCT and verified its usefulness. However, as the setting phase decreases, the scan time was increases. Therefore, considering the scan time and the error in setting phase, It is recommended to apply it to patients with respiratory coordinated stereotactic radiation therapy using a wide phase of 30-70% or more.

• Conservation Science in Museum
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• v.24
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• pp.81-98
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• 2020

This paper presents the results of a comprehensive nondestructive analysis of Portrait of Master Gowun at Wunamyeongdang Shrine (Hereafter, Portrait of Choe Chiwon), Tangible Cultural Heritage No. 187 of Gyeongsangnam-do, including the underlying images drawn at the time of its production and the pigments present. The analysis revealed that the portrait was produced in 1793 at Ssanggyesa Temple in Hadong, Gyeongsangnam-do, which makes it the earliest known example among the extant portraits of Choe Chiwon. X-ray examination found images of a half-length boy monk and a full-length boy monk on either side of the portrait, which had been painted over and became invisible to the naked eye. XRF analysis of the pigments indicated that white lead was used for white, cinnabar and red lead for red, malachite for green, azurite for blue, and gold for gold. It was revealed that the overpainted boy monks were colored using the same pigments as those applied in the portrait of the main figure. It is hoped that the analysis of the pigments used for the boy monks can provide basic materials for research on the production of copied portraits and local Buddhist paintings. Also, additional research drawing upon other fields of study is required to examine the details of the inscription of the portrait.

• Nuclear Engineering and Technology
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• v.49 no.7
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• pp.1442-1450
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• 2017

In liquid metal fast breeder reactors, postulated failures of the plant protection system may lead to serious unprotected accidental consequences. Unprotected transients are generically categorized as transient overpower accidents and transient under cooling accidents. In both cases, core meltdown may occur and this can lead to a molten fuel coolant interaction (MFCI). The understanding of MFCI phenomena is essential for study of debris coolability and characteristics during post-accident heat removal. Sodium is used as coolant in liquid metal fast breeder reactors. Viewing inside sodium at elevated temperature is impossible because of its opaqueness. In the present study, a methodology to depict MFCI phenomena using a flat panel detector based imaging system (i.e., real time radiography) is brought out using a woods metal-water experimental facility which simulates the $UO_2-Na$ interaction. The developed imaging system can capture attributes of the MFCI process like jet breakup length, jet front velocity, fragmented particle size, and a profile of the debris bed using digital image processing methods like image filtering, segmentation, and edge detection. This paper describes the MFCI process and developed imaging methodology to capture MFCI attributes which are directly related to the safe aspects of a sodium fast reactor.