• Journal of the Korean Society of Clothing and Textiles
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• v.19 no.5
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• pp.765-773
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• 1995

Effect of interfacial electrical conditions such as, the f potential of PET fiber and u-Fe203 particles, the stability parameter and potential energy of interaction on adhesion of a-Fe903 particles to PET fabric and their removal from the fabric, were investigated as functions of pH, electrolyte and ionic strength. The stability parameter, potential energy of interaction between a-Fe2O3 particles and PET fabric were calculated by using the heterocoagulation theory for a sphere-plate model The adhesion of a-Fe2O3 particles to PET fabric and their removal from PET fabric were carried out by using water bath shaker and Terg-O-Tometer under various solution conditions. The adhesion of a-Fe2O3 particles to the PET fabric and the removal of a-Fe2O3 particles from the PET fabric were biphasic and were maximum and minimum at pH 7~8, respectively. With high pH and polyanion electrolytes in solution, the adhesion of a-Fe2O3 particles to the PET fabric was low but effects of electrolytes on the removal of a-Fe2O3 particles from the PET fabric was small. The adhesion of a-Fe2O3 particles to the PET fabric and the removal of a-Fe2O3 Particles from the PET fabric were biphasic, and were lowest and highest at the ionic strength 1$\times$10-3, respectively. The adhesion of a-Fe2O3 particles to PET fabric was well related with the interfacial electrical conditions; it was negatively correlated with the f potentials of a-Fe2O3 Particles of its absolute value, the stability parameter and the maximum of total potential energy, while, the adhesion was not related with the t potentials of PET fiber itself. Therefore, the primary factor determining the adhesion of a-Fe203 particles to PET fabric may be the stability of dispersed particles caused by the electrical repulsion of particles. The removal of a-Fe203 particles from PET fabric was not related to such interfacial electrical conditions as the t potentials of PET fiber, the stability parameter and the maximum of total potential energy but removal was related to t potential of a-Fe203 particles.

• Journal of Educational Research in Mathematics
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• v.23 no.4
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• pp.467-490
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• 2013

Correlation is a basic statistical concept which is necessary for understanding the relationship between two variables when they change values. In the middle school curriculum of Korea, only informal definition of correlation is taught with two-way data representations such as scatter plots and contingency tables. In this study, we investigated Korean high school students' understanding of correlation using a test consisting of 35 items about interpretation of scatter plot, contingency table, and text in realistic situation. 216 students from a high school in Seoul took the test for 20 minutes. From the results, we could observe the following: First, students did not have right criteria for determining the strength of correlation presented in scatter plots. Most of students could determine if there is correlation/no correlation and if the correlation is positive/negative by seeing the data presented in scatter plots. However, they did not judge by the closeness to the regression line but rather judged by the closeness between data points. Second, when statements about comparing the strength of correlation in the context of real life situation were given in text, the students had difficulty in understanding the distribution-related characteristic of the bi-variate data. Students had difficulty in figuring out the local distribution characteristic of data, which cannot be guessed merely based on the expression 'The correlation is strong' without statistical knowledge of correlation. Third, a large number of students could not judge the association between two variabels using conditional proportions when qualitative data are given in 2-by-2 tables. They made judgement by the absolute cell count and when the marginal sum of two categories are different for explanatory variable they thought the association could not be determined. From these results, we concluded that educational measures are required in order to remove such misconceptions and to improve understanding of correlation. Considering that the current mathematics curriculum does not cover the concept of correlation, we need to improve the curriculum as well.

• Child Health Nursing Research
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• v.5 no.2
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• pp.185-197
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• 1999

In the family life cycle, the most important task the families with school children should perform is ‘child education’ and ‘socialization’ However, economic stress on poor families with school children presents multiple problems through the shortage of resources necessary for child education and socialization, inappropriateness of family appraisal, and the insufficiency of the control channels for the efficient management of these confined resources and appropriate appraisal. The objectives of this article are : First, to report research on the actual conditions of the poor families in one area of Cheju and on the relevant health welfare policy, and to examine the appropriateness of the direction and the substance of this policy in terms of the intervention in economic stress on the poor families under the categories of resource management and control of appraisal. Second, to analyze qualitative data extracted from the memoirs of single-parent families living in several areas of Korea under the conceptual framework constructed by literature review in order to get a better understanding of the stress which poor families with school children have experienced. And third, to confirm the factors that can be risk factor but, at the same time, strength to these poor families from presented data and to use them as the basic data from which an intervention model can be developed, based on resource management and control of appraisal. The findings of this article are : First, while the number of absolute poor families in one area of Cheju is increasing and, as a result, the danger of the possibility that multiple problems will occur is also growing, the supporting level of the current policy is no more than a direct resource offer and there is no evidence that resource management is being professionally carried out. When it comes to control of appraisal, due to absence of the professional human resources in this matter, policy performances such as technical education training can have a negative impact. Second, a conceptual framework introduced in this article, ; Economic Pressure → Helplessness → Poor self-esteem → Marital Conflict → Parent-Child financial conflict → Inappropriate socialization → Poor child social competence : is partly verified. And third, judging from the results of the qualitative data, it is confirmed that the healing families, having overcome poverty, show several positive characteristics including : hope, strength, and social support. These findings are identified with the factors of resiliency considered above. According to these results, this article suggests the following. The anti -poverty policy in the future should focus not only on a direct resource offer but also on resource management and the control of appraisal that can magnify its effects. In particular, close attention should be paid to school children since they are in the most crucial period for socialization. Moreover, an emotional labor is such an essential resource for intervention that skilled nurses should play pivotal roles.

• Journal of National Security and Military Science
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• s.8
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• pp.239-270
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• 2010

This thesis is to make an appropriate national defense policy of Republic of Korea through studying the Hegemony Strategy of United States. I searched the theory of hegemony. The hegemony was differently defined by the point of time and region. The strong power nations with the hegemony have been making efforts to maintain their hegemony everytime. I have conclusion that the presence of hegemony once emerged, it brought regional stability in place whether it is coercive or beneficial. The stability and instability of international order IS not exclusively dependent on hegemony. Even if the safety of hegemony cannot guarantee absolute stability of international order, there IS on doubt that the hegemony has enormous impact on that. According to the hegemonic theory, the history of mankind equals to the history of rising and falling hegemony. The international order was changed as the hegemony changes. The United States has been making efforts to maintain her global hegemony during the post cold-war era as well. Taking all these into consideration, relevant military strategy direction able to pursue national interest is that to make up for the relative weakness in the strategic environment. South Korea have to prepare security policy response as following. First, South Korea should build the military force equipped with advanced weapons in military technology sector and solidify military diplomatic relation able to form cooperative relation in wartime. Second, South Korea should make solid Alliance of Korea and U.S. Third, develop and maintain multilateral security cooperation of East Asia. Forth, we could realize that there are means that can neutralize opponent's strong point by seeking one or two and more asymmetry in the aspect of strategy, tactics, and means through asymmetric strategy. Than the military force of South Korea should develop into a force that is able to overcome to the traditional North Korea's threat and new type of conflicts. And the force should have sufficient strength and be deployed to effectively defend the Korean Peninsula. So, we need to establish a denial and defense system against any hostile neighboring country. Therefore, ROK military forces preparing for the future should try to construct a future military power to gradually establish enough strength for self-defense to prepare for a uncertain security environment and when the Korean Peninsula is unified in a future.

• Geophysics and Geophysical Exploration
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• v.9 no.1
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• pp.50-59
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• 2006

The risk of fault reactivation in the Gippsland Basin was calculated using the FAST (Fault Analysis Seal Technology) technique, which determines fault reactivation risk by estimating the increase in pore pressure required to cause reactivation within the present-day stress field. The stress regime in the Gippsland Basin is on the boundary between strike-slip and reverse faulting: maximum horizontal stress $({\sim}\;40.5\;Mpa/km)$ > vertical stress (21 Mpa/km) ${\sim}$ minimum horizontal stress (20 MPa/km). Pore pressure is hydrostatic above the Campanian Volcanics of the Golden Beach Subgroup. The NW-SE maximum horizontal stress orientation $(139^{\circ}N)$ determined herein is broadly consistent with previous estimates, and verifies a NW-SE maximum horizontal stress orientation in the Gippsland Basin. Fault reactivation risk in the Gippsland Basin was calculated using two fault strength scenarios; cohesionless faults $(C=0;{\mu}=0.65)$ and healed faults $(C=5.4;\;{\mu}=0.78)$. The orientations of faults with relatively high and relatively low reactivation potential are almost identical for healed and cohesionless fault strength scenarios. High-angle faults striking NE-SW are unlikely to reactivate in the current stress regime. High-angle faults oriented SSE-NNW and ENE-WSW have the highest fault reactivation risk. Additionally, low-angle faults (thrust faults) striking NE-SW have a relatively high risk of reactivation. The highest reactivation risk for optimally oriented faults corresponds to an estimated pore pressure increase (Delta-P) of 3.8 MPa $({\sim}548\;psi)$ for cohesionless faults and 15.6 MPa $({\sim}2262\;psi)$ for healed faults. The absolute values of pore pressure increase obtained from fault reactivation analysis presented in this paper are subject to large errors because of uncertainties in the geomechanical model (in situ stress and rock strength data). In particular, the maximum horizontal stress magnitude and fault strength data are poorly constrained. Therefore, fault reactivation analysis cannot be used to directly measure the maximum allowable pore pressure increase within a reservoir. We argue that fault reactivation analysis of this type can only be used for assessing the relative risk of fault reactivation and not to determine the maximum allowable pore pressure increase a fault can withstand prior to reactivation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5915-5922
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• 2013

In this study, with the aim of improving the performance of shale to allow for its use as coarse aggregate for concrete, we coated shale aggregates with water repellents and polymers and evaluated their physical properties such as density, water absorption rate, wear rate, and stability depending on the coating method. In addition, the effects of the performance improvement were evaluated by assessing the properties of fresh concrete produced by varying the shale substitution ratio, as well as the compressive strength, flexural strength, and freeze-thaw resistance according to curing ages. The test results revealed that the absolute dry densities of all coated aggregates satisfied the standard density for coarse aggregates for concrete(>$2.50g/cm^3$),and the absorption rate of the shale aggregate coated with water repellent decreased by about 50% compared with that of uncoated shale. The wear rate of the polymer-coated shale decreased by up to 13.0% compared with that of uncoated shale. All coated aggregates satisfied the stability standard for coarse aggregates for concrete(${\leq}12$). The water repellent-induced performance improvement decreased the shale aggregates' slump by about 20~30mm compared with that of the uncoated shale aggregates, and the air content of the repellent-coated shale aggregate increased by up to 0.9% compared with that of the uncoated shale aggregate. The compressive strength of the polymer-coated shale aggregates at a curing age of 28 days was RS(F) 95.7% and BS(F) 90.0%, and the flexural strength was RS(F) 98.0 % and BS(F) 92.0% of the corresponding values of concretes produced using plain aggregates. Furthermore, the concrete using polymer-coated shale aggregates showed a dynamic modulus of elasticity of RS(F) 91% and BS(F) 88% after 300 freeze-thaw cycles, thus demonstrating improved freeze-thaw durability.

• Korean Journal of Cognitive Science
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• v.16 no.4
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• pp.305-322
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• 2005

Watermarking is a widely employed method tn protecting copyright of a digital image, the owner's unique image is embedded into the original image. Strengthened level of watermark insertion would help enhance its resilience in the process of extraction even from various distortions of transformation on the image size or resolution. However, its level, at the same time, should be moderated enough not to reach human visibility. Finding a balance between these two is crucial in watermarking. For the algorithm for watermarking, the predefined strength of a watermark, computed from the physical difference between the original and embedded images, is applied to all images uniformal. The mean brightness or contrast of the surrounding images, other than the absolute brightness of an object, could affect human sensitivity for object detection. In the present study, we examined whether the detectability for watermark noise might be attired by image statistics: mean brightness and contrast of the image. As the first step to examine their effect, we made rune fundamental images with varied brightness and control of the original image. For each fundamental image, detectability for watermark noise was measured. The results showed that the strength ot watermark node for detection increased as tile brightness and contrast of the fundamental image were increased. We have fitted the data to a regression line which can be used to estimate the strength of watermark of a given image with a certain brightness and contrast. Although we need to take other required factors into consideration in directly applying this formula to actual watermarking algorithm, an adaptive watermarking algorithm could be built on this formula with image statistics, such as brightness and contrast.

• Journal of Bio-Environment Control
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• v.32 no.2
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• pp.97-105
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• 2023

Concentration of nitrogen, one of the major elements, and ratio of two nitrogen forms (NH₄⁺ and NO₃^-) in the nutrient solution affect the quality and food safety of fresh vegetable produce. This study was conducted to find an appropriate strength and NH₄⁺:NO₃^- ratio of a nutrient solution for growth and development of a Romaine lettuce (Lactuca sativa L. var. longiflora) 'Caesar Green', a representative leafy vegetable, grown in a home hydroponic system. In the first experiment, plants were grown using three types of nutrient solution: A commercial nutrient solution (Peters) and two strengths (GNU1 and GNU2) of a multipurpose nutrient solution (GNU solution) developed in a Gyeongsang National University lab. Plants grown with the GNU1 and GNU2 had greater shoot length, leaf length and width, and biomass yield than Peters. On the other hand, the root hairs of plants grown with Peters were short and dark in color. Tissue NH₄⁺ content in the Peters was higher than that of the GNU1 and GNU2. The higher contents of NH₄⁺ in this solution may have caused ammonium toxicity. In the second experiment, eight treatment solutions, combining GNU1 and GNU2 solutions with four ratios of NO₃^- :NH₄⁺ named as 1, 2, 3 and 4 were used. Both experiments showed more growth in the GNU2 group, which had a relatively low ionic strength of the nutrient solution. The growth of Romaine lettuce showed the greatest fresh weight along with low tissue NO₃^- content in the GNU2-2. This was more advantageous in terms of food safety in that it suppressed the accumulation of surplus NO₃^- in tissues due to the low ionic trength of the GNU2 subgroup. In addition, this is preferable in that it can reduce the absolute amount of the input of inorganic nutrients to the nutrient solution.

• Journal of the Korean Magnetics Society
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• v.26 no.3
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• pp.92-98
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• 2016

To aim of this study was to assess the full scan and half scan of imaging with half scan factor. Patients without a cerebral vascular disease (n = 30) and were subject to the full scan half scan, and set a region of interest in the cerebral artery from the three regions (C1, C2, C3) in the range of 7 to 8 mm. MIP (maximum intensity projection) to reconstruct the images in signal strength SNR (signal to noise ration), PSNR (peak signal noise to ratio), RMSE (root mean square error), MAE (mean absolute error) and calculated by paired t-test for use by statistics were analyzed. Scan time was half scan (4 minutes 53 seconds), the full scan (6 minutes 04 seconds). The mean measurement range (7.21 mm) of all the ROI in the brain blood vessel, was the SNR of the first C1 is completely scanned (58.66 dB), half-scan (62.10 dB), a positive correlation ($r^2=0.503$), for the second C2 SNR is completely scanned (70.30 dB), half-scan (74.67 dB) the amount of correlation ($r^2=0.575$), third C3 of a complete scan SNR (70.33 dB), half scan SNR (74.64 dB) in the amount of correlation between the It was analyzed with ($r^2=0.523$). Comparative full scan with half of SNR ($4.75{\pm}0.26dB$), PSNR ($21.87{\pm}0.28dB$), RMSE ($48.88{\pm}1.61$), was calculated as MAE ($25.56{\pm}2.2$). SNR is also applied to examine the half-scans are not many differences in the quality of the two scan methods were not statistically significant in the scan (p-value > .05) image takes less time than a full scan was used.

• The Korean Journal of Archival Studies
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• no.13
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• pp.179-203
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• 2006

This study develops the process and method of official administration documents which have remained ill-balanced like the official documents of the government-general of Chosun(the pro-Japanese colonial government (1910-1945)). At first, the existing Appraisal-theories are recomposed. The Appraisal-Theories of Schellenberg is focused valuation about value of records itself, but fuction-Appraisal theory is attached importance to operational activities which take the record into action. But given that the record is a re-presentation of operational activities, the both are the same on the philosophy aspect. Therefore, in the case that the process - method is properly designed, it can be possible to use a composite type between operational activities and records. Also, a method of the Curve has its strong points in the macro and balanced aspect while the Absolute has it's strength in the micro aspect, so that chances are that both alternate methodologies are applied to the study. Hereby, the existing Appraisal theories are concluded to be the mutually-complemented things that can be easily put together into various forms according to the characteristics of an object and its situation, in the terms of the specific Appraisal methodology. Especially, in the case of this article dealing with the imbalance remains official-documents, it is necessary to compromise more properly process with a indicated useful method than establishing a method and process by choosing the only one theory. In order to appraise the official-documents of the pro-Japanese colonial government (1910-1945), a macro appraisal of value has to be appraised about them by understanding a system, functions and using the historical-cultural evolution, after analysing Disposal Authority. From this, map the record so that organization function maps are constructed regarding the value rank of functions and detailed-functions. After this, establish the appraisal strategy considering the internal environment of archival agencies and based on micro appraisal to a great quantity of records remained and supplying other meaning to a small quantity of records remained for example, the oral resources production are accomplished. The study has not yet reached the following aspects ; a function analysis, historical decoding techniques, a curve valuation of the record, the official gazette of the government general of Chosun( the pro-Japanese government for 1910-1945), an analysis method of the other historical materials and it's process, presentation of appraisal output image. As the result, that's just simply a proposal and we should fill in the above-mentioned shortages of the study through development of all the up-coming studies.