• Imaging Science in Dentistry
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• v.37 no.4
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• pp.211-215
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• 2007

Purpose: The purpose of this study was to evaluate the effect of the kV on fractal dimension of trabecular bone in digital radiographs. Materials and Methods: 16 bone cores were obtained from patients who had taken partial resection of tibia due to accidents. Each bone core along with an aluminum step wedge was radiographed with an occlusal film at 0.08 sec and with the constant film-focus distance (32 cm). All radiographs were acquired at 60, 75, and 90 kV. A rectangular ROI was drawn at medial part, distal part, and the bone defect area of each bone core image according to each kV. The directional fractal dimension was measured using Fourier Transform spectrum, and the anisotropy was obtained using directional fractal dimension. The values were compared by the repeated measures ANOVA. Results : The fractal dimensions increased along with kV increase (p < 0.05). The anisotropy measurements did not show statistically significant difference according to kV change. The fractal dimensions of the bone defect areas of the bone cores have low values contrast to the non-defect areas of the bone cores. The anisotropy measurements of the bone defect areas were lower than those of the non-defect areas of the bone cores, but not statistically significant. Conclusion: Fractal analysis can notice a difference of a change of voltage of x-ray tube and bone defect or not. And anisotropy of a trabecular bone is coherent even with change of the voltage of x-ray tube or defecting off a part of bone.

• Imaging Science in Dentistry
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• v.34 no.4
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• pp.179-182
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• 2004

Purpose: The purpose of this study is to examine the effects of X-ray beam angulation on the fractal dimension of trabecular bone structure of human dry mandible using the tile counting method. Materials and Methods: We divided 5 human dry mandibles into an angle and a molar groups depending on the regions and deciding the region of interest (ROI). When contrasted with the ROI, the inferior cortex was appointed to be low and the lines perpendicular to the buccal cortex were appointed to be the standard angle. Direct digital intraoral radiographs were obtained from 9 different projection angles. We analyzed statistically the fractal dimension using the tile counting method. Results: There was a statistically significant difference in the fractal dimension of the regions and the mandibles, but there was no statistically significant difference in the fractal dimension according to the X-ray beam angulation. Conclusion : There is no statistically significant effect of the angle of the projection on the fractal dimension of trabecular bone structure of a human dry mandible according to the tile counting method.

• Journal of Conservation Science
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• v.27 no.1
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• pp.91-100
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• 2011

This study is to examine the PEG concentration, and drying humidity and drying periods of humidity-controlled drying(HCD) for conservation of waterlogged woods(Pinus densiflora S. et Z.), and dimension stability of HCD were compared with those of air-drying and vacuum freeze-drying(VFD). Dimension stability of vacuum freeze-drying was the most excellent, i.e., PEG crystal was uniformly distributed in woods. Increasing concentrations of PEG, dimension stability of HCD was increased and drying periods decreased. Dimension stability of HCD after the treatment with the high concentration(70%) of PEG soaking was similar to those of VFD after the treatment with the low concentration(40%) of PEG soaking. In conclusion, high concentration(about 70% in water) PEG solution was the most suitable as a pre-treatment for HCD of waterlogged woods. However, drying should be maintained with enough high humidity and longer period.

• Journal of dental hygiene science
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• v.12 no.3
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• pp.259-269
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• 2012

This study examined in what category that the knowledge dimension and the cognitive processes dimension are described based on 'A revision o Bloom's taxonomy of educational objectives' in oral health education textbooks. Oral health education and practice from Educational Objectives of Dental Hygiene Department(Korea dental hygienist Prof Council, 2009) were selected to analyze a textbook, the body contents was analyzed in the knowledge dimension, and the activity was analyzed in cognitive processes dimension. Three experts were selected as a corder for reliable analysis. As a result of this study, the knowledge dimension in oral health education textbook was focused on the categories of factual knowledge and conceptual knowledge in textbook analysis based on 'A revision of Bloom's taxonomy of educational objectives', and the category dimension of 'understand' showed to be the most for the cognitive processes dimension. Moreover, there was no 'meta cognitive knowledge' that conforms to a higher-order thinking and the category dimensions of 'analyze', 'evaluate', and 'create' took very low proportion or did not exist. Conclusion, Oral health education textbooks were analyzed to fragmentary and Memorizing the level knowledge. Thus we have to develop oral health education textbooks reflected a variety of cognitive and knowledge dimension.

• Survey Research
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• v.11 no.1
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• pp.63-85
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• 2010

This study defines the substance and multi-dimension of emotional reactions which Koreans have toward foreigners to find the starting point of change in values which is an inevitable task in this multi-cultural society. The results indicate that the Bogardus scale which has been used to measure the social distance toward the minority race is found to have limitations in explaining the closed attitude of Koreans toward 'nation' and 'kinship through marriage'. To supplement such limitations, exploration on attitudes toward foreigners from different native places is performed based on the 'evaluation', 'power' and 'activity' dimensions of the Affective Control Theory. As a result, Americans are highly evaluated in all three dimensions while Japanese are evaluated low in the 'evaluation' dimension and high in the 'power' and 'activity' dimensions. North Korean defectors and ethnic Koreans from China (the Chosun race) are high in evaluation but low in other dimensions. West Asians are evaluated low in all three dimensions. By comprehending the influencing factors and the relative influence of social distance, it proves that the 'evaluation' dimension is the common denominator in all groups while 'power' dimension toward Japanese and 'activity' dimensions toward Chinese and West Asians influence social distance. All foreigners excluding Americans receive closer social distance when having higher education level. Moreover, American women and older North Korean defectors receive closer social distance.

• Journal of Korean Academy of Nursing Administration
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• v.3 no.1
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• pp.37-50
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• 1997

The purpose of this study was to identify the gap between need-level and demonstration-level in nursing managerial competencies. In addition, the study proposes solutions to narrow this gap. The results of this study are as follows : 1) The mean score for need-level of each item was 4.0, and for demonstration-level, 3.5. This indicates that military hospital head nurses demonstrate a higher level of managerial competencies than the moderate level on all items. But items which were related to resource/ cost/ information managament, staff development management and professionalism management got relatively low ratings in the need-level. 2) The mean score for need-level of each category was 4.14, and for demonstration-level, 3.53. Categories on the individual dimension got a higher rating than categories on the group or organization dimension in both need-level and demonstration level. 3) The gap between need-level and demonstration-level appeared in all items(p<.05) and categories(p<.001). Although the gap was relatively low, it indicates that it is essential to plan a developmemt program for all nursing management competencies for military hospital head nurses. 4) There were significant differences in the gap between need-level and demonstration-level according to specific characteristics of the subjects. The gap did not appear in many categories on the individual dimension where the number of nursing staff was more than 10, a major grade, ICU head nurse or for head nurses having a long career. 5) Need-level and demonstration-level showed a difference according to specific characteristics of the subjects, because need-level and demonstration-level were higher where the number of nursing staff was more than 10, a major grade, and for ICU or Medical ward head nurses. The categories which showed need-level difference and demonstration-level differences according to specific characteristics of the subjects existed almostly completely in the group and organization dimension. Gap-level differences according to the number of hospital bed existed in only two categories. 6) The general causes of the gap were indicated to be 'Knowledge/ skill/ experience deficit', 'Limitation of rules and systems/ Inappropriate organizational environment' for most items, categories, and dimensions. The results of this study indicate that extensive competency developing strategies must be developed, because a gap was found in all items and categories. Specially, there is a need to concentrate attention on competencies in the group and organizational dimension which had a wider gap level. And it is important to take an individual approach according to the cause for each gap. In order to produce effective competency developing strategies, top managers must have sinsights into the importance of nursing staff development and nursing officer's efforts to develop themselves must be achieved. Further multi-dimensional(education, personnel-policy, nursing/ organizational environment) solutions to the gap must be developed and utilized.

• Earthquakes and Structures
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• v.8 no.2
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• pp.423-442
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• 2015

The effects of accidental eccentricity on the seismic response of four-storey steel buildings laterally stabilized by buckling restrained braced frames are studied. The structures have a square, symmetrical footprint, without inherent eccentricity between the center of lateral resistance (CR) and the center of mass (CM). The position of the bracing bents in the buildings was varied to obtain three different levels of torsional sensitivity: low, intermediate and high. The structures were designed in accordance with the seismic design provisions of the 2010 National Building Code of Canada (NBCC). Three different analysis methods were used to account for accidental eccentricity in design: (1) Equivalent Static Procedure with static in-plane torsional moments assuming a mass eccentricity of 10% of the building dimension (ESP); (2) Response Spectrum Analysis with static torsional moments based on 10% of the building dimension (RSA-10); and (3) Response Spectrum Analysis with the CM being displaced by 5% of the building dimension (RSA-5). Time history analyses were performed under a set of eleven two-component historical records. The analyses showed that the ESP and RSA-10 methods can give appropriate results for all three levels of torsional sensitivity. When using the RSA-5 method, adequate performance was also achieved for the low and intermediate torsional sensitivity cases, but the method led to excessive displacements (5-10% storey drifts), near collapse state, for the highly torsionally sensitive structures. These results support the current provisions of NBCC 2010.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12B
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• pp.2391-2400
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• 1999

Vector quantizer (VQ) is an efficient data compression technique for low bit rate applications. However, the major disadvantage of VQ is its encoding complexity which increases dramatically as the vector dimension and bit rate increase. Even though one can use a modified VQ to reduce the encoding complexity, it is nearly impossible to implement such a VQ at a high bit rate or for a large vector dimension because of the enormously large memory requirement for the codebook and the very large training sequence (TS) size. To overcome this difficulty, in this paper we propose a novel structurally constrained VQ for the high bit rate and the large vector dimension cases in order to obtain VQ-level performance. Furthermore, this VQ can be extended to the low bit rate applications. The proposed quantization scheme has a form of feed-forward adaptive quantizer with a short adaptation period. Hence, we call this quantization scheme sample-adaptive product quantizer (SAPQ). SAPQ can provide a 2 ~3dB improvement over the Lloyd-Max scalar quantizers.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.451-454
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• 1997

It has been reported that sudden cardiac death and ventricular tachycardia occur after treatment of tetralogy of fallot(TOF). It is regarded that ventricular arrythmia is the main source or the sudden cardiac death, but it is not verified. It is likely that TOF has effect on the heart rate variability because of the ventricular arrythmia. We study how complex and periodic heart rate dynamics change in the normal children (n=13) and TOF children (n=13) throughout 24 hours. We recorded 24-hour holter ECG, and segmented each ECG data into 1 hour length. We analyze each HR time series, and quantify the overall complexity of each HR time series by its correlation dimension. We also calculate the power spectrum of HR, and obtain low-frequency component (0.03-0.15Hz) and high-frequency component (0.15-0.4Hz). We compare the results between normal and TOF groups throughout 24 hours. TOF group have lower correlation dimension ($4.055{\pm}0.4134$ vs. $4.9310{\pm}0.2054$, p<0.05) than the normal group, even though there are no significant differences in the low($0.9864{\pm}0.5598$ vs. $1.5560{\pm}0.8325$, p<0.05) and high($1.1168{\pm}0.1.1448$ vs. $0.9271{\pm}0.6528$, p<0.05) frequency components. It can be concluded that HR time series of TOF group are more regular than that of normal group, and that correlation dimension reveals a nonlinear characteristics of HR time series which is not determined in the frequency domain.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.6.1-6.1
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• 2011

Nanoscale block copolymer (BCP) patterns have been pursued for applications in sub-30 nm nanolithography. BCP self-assembly processing is scalable and low cost, and is well-suited for integration with existing semiconductor fabrication techniques. However, one of the major technical challenges for BCP self-assembly is limited tunability in pattern geometry, dimension, and functionality. We suggest methods for extending the degree of tunability by choosing highly incompatible polymer blocks and utilizing solvent vapor treatment techniques. Siloxane BCPs have been developed as self-assembling resists due to many advantages such as high etch-selectivity, good etch-resistance, long-range ordering, and reduced line-edge roughness. The large incompatibility leads to extensive degree of pattern tunability since the effective volume fraction can be easily manipulated by solvent-based treatment techniques. Thus, control of the microdomain size, periodicity, and morphology is possible by changing the vapor pressure and the mixing ratio of selective solvents. This allows a range of different pattern geometry such as dots, lines and holes and critical dimension simply by changing the processing conditions of a given block copolymer without changing a polymer chain length. We demonstrate highly extensive tunability (critical dimension ~6~30 nm) of self-assembled patterns prepared by a siloxane BCP with extreme incompatibility.