• Journal of the Korean Crystal Growth and Crystal Technology
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• v.21 no.6
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• pp.253-258
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• 2011

Electro-mechanical coupling performance ($k_t$) of a 1-3 type Piezo-composite was analyzed numerically using FEM. The calculated physical properties of the PZT ceramics were compared with the experimental data and the accuracy of the numerical method was verified. Also the $k_t$ of the composite was analyzed with the vol% and the material properties of the constitutional parts, and the aspect ratio of the PZT rod. As the simulated results, the $k_t$ increased rapidly when the vol% of the PZT ceramics increased up to 30 vol% and saturated the constant value in the above region. And the composite using the soft matrix polymer than the hard one have the superior $k_t$ characteristics. The $k_t$ was greatly influenced by the aspect ratio of the PZT rod up to 30 vol% of PZT ceramics. To improve the $k_t$ characteristics, it is useful that the composite consist of the relatively flexible polymers and the PZT material having the excellent piezoelectric characteristics.

• Journal of the Korean Geosynthetics Society
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• v.14 no.2
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• pp.23-33
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• 2015

The earth pressure acting on underground structure was measured by application of the instrumentation system in the subway construction site constructed by the method of cut-and-cover tunnel. The measured earth pressure was compared with the earth pressure obtained from the existed theoretical equation, and the actual earth pressure diagram acting on the underground structure was investigated. As a result of investigation, the vertical earth pressure is mainly affected by the embankment height, and the lateral earth pressure is significantly affected by whether the existence of earth retaining structures or not. The measured vertical earth pressure is very similar to the theoretical earth pressure proposed by Bierbaumer. The measured lateral earth pressure is closed to the active earth pressure proposed by Rankine rather than the earth pressure at rest. The coefficient of earth pressure in soil deposit layer is about 0.35, and the coefficient in soft rock deposit layer is about 0.21. For design and construction the underground structures, therefore, it is reasonable estimation that the lateral earth pressure acting on structures installed in soil deposit layers is an average value between active earth pressure and earth pressure at rest. In rock deposit layers, the lateral earth pressure acting on structure is an active earth pressure only.

• Journal of the Korean Geosynthetics Society
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• v.17 no.3
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• pp.1-8
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• 2018

Sand compaction pile (SCP) is a ground improvement method which is used to secure the stability of the soft ground by using a type of replacement pile filled with coarse grained material. The behavior characteristics of the SCP, which is frequently used for improving both the onshore and offshore ground, is governed by the ground condition, the installation method, and replacement ratio. Therefore, the stability of the SCP in terms of the bearing capacity and displacement needs to be evaluated considering both the design values and in-situ conditions of construction site. In this study, numerical analysis is carried out based on the conditions of 00 revetment construction site in South Korea where unexpected displacement occurred during construction of SCP. Based on the analysis results, the displacement of the revetment structure according to the replacement ratio of the SCP was compared to the result calculated from design formulas. The results showed that the lateral displacement can be exceeded the reference value from proposed criteria regardless of increased replacement ratio of SPC. It is also confirmed that the behavior of the structure according to the replacement ratio of SPC in not reflected in the existing calculation methods. Therefore, the stability of the SCP composite ground should be examined through the site inspection after the SCP construction.

• Journal of the Korean Geosynthetics Society
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• v.17 no.3
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• pp.9-18
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• 2018

The soil parameters important for the design of the soft ground are the compression index ($C_c$), the consolidation settlement and consolidation speed at the field. Compression index is obtained by laboratory consolidation test. In the laboratory consolidation test, sample disturbance always occurs. In order to correct the disturbance phenomena, the method of calculating the compression index proposed by Schmertmann (1955) is generally used. However, recent developments in sampling technology and Korean soil conditions are different from those proposed by Schmertmann. So it needs to be verified. In this study, each consolidation curve's cross void ratio is evaluated by doing consolidation test varying disturbance on high-plastic clay (CH), low-plastic clay (CL) and low-plastic silt (ML). The test results were $0.521e_0$ for low-plastic silt, $0.404e_0$ for low-plastic clay, and $0.458e_0$ for the high-plastic clay. This results were different from those of Schmertmann's suggested value of $0.42e_0$. Therefor we proposed a correction formula using the plastic index according to soil type. However, since the results of this study are limited test results, further studies on various korean soil are needed to suggest the compression index correction method according to the degree of plasticity index of soil.

• International Journal of Costume and Fashion
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• v.13 no.1
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• pp.23-34
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• 2013

The purpose of this study is to better understand the development and characteristics of knitwear fashion design by examining the transformation process of the modern knits. The subjects of the study are Missoni, Sonia Rykiel, and Azzedine Alaia, designers who are world-renowned knit designers, and the expressive techniques in their designs will be evaluated. The study also intends to analyze the aesthetic value of each designer's style through their product's silhouette, colors, and knitting techniques. On the basis of the analysis, we hope to research the factors in the designing process that will allow knits, which were made for practical purposes, to be valued as a luxury fashion item, and with the results, show the potential for knits in expanding its domain in fashion to become a more luxurious, creative fashion item. The characteristic comparison of the designers is as follows: First, in the case of colors, Missoni shows its distinct identity through a balance of splashy colors as well as nature-inspired color composition and balance. And, only with color use, is also able to express perspective, form composition, and rhythm. Sonia Rykiel designs are composed of black backgrounds with strong primary colors that are contrasted with one-point or stripes to express a light, urban image. Alaia emphasizes femininity by the use of black and white colors, which show modernity, in combination with neutral skin-toned colors, such as beige and gray. So, in other words, Missoni and Sonia Rykiel mixed colors for visual interconnectivity, while Alaia expressed femininity through the use of an achromatic color. Second, in the case of knitting techniques, Missoni uses the jacquard technique to make complex patterns that show balance of colors and patterns such as zigzag, stripe, geometries, and titan check, which are geometric, abstract, and symmetric. Sonia Rykiel who uses stripes as her trademark, most often utilizes the intarsia technique, which is expressed through one-point. Alaia combines diverse techniques, such as the Skashi weaving, by using computerized knitting. Third, as for silhouettes, Missoni eliminated exaggerated details in order to emphasize the flashy colors and delicate patterns and weavings of its designs, and this resulted in simplistic and relaxed silhouettes. Sonia Rykiel took advantage of the elasticity that the knit offers to get a tight silhouette, and in turn, emphasized the female sensuality. Alaia used curvilinear cuts that emphasized the womanly curves and gained an image considered soft and feminine.

• The Journal of the Korean bone and joint tumor society
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• v.2 no.1
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• pp.1-7
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• 1996

PURPOSE : The purpose of this study is to know the ability of detecting malignant tumor tissue by Tl-201 scan, and to compare with that of Tc-99m-MIBI and Tc-99m-MDP scan. MATERIAL AND METHODS : Between February 1994 and December 1995,38 unselected patients with various bone pathologies were studied prospectively. Eighteen had malignant bone and soft tissue pathologies, while twenty had benign. All patients were studied with Tl-201, Tc-99mMIBI and Tc-99m-MDP scan prior to surgical biopsy. PICKER Prism 2000 gamma camera with high resolution parallel hole collimator was used for scanning. To avoid the interaction of isotope, the early(30min.) and delayed phase(3hrs.) of Tl-20l scan was performed first and Tc-99m-MIBI scan was performed after 30 minutes, and then Tc-99m-MDP scan 48 hours later. The scan images were visually evaluated by a blinded nuclear medicine physician. We could find true positive, true negative, false positive and false negative by the comparison of results with those of biopsy. We calculated positive and negative predictive value(%), sensitivity(%), specificity(%) and diagnostic accuracy(%) of each scan. RESULT : The results of each scan were 85.7, 100, 100, 85, 92.1% in Tl-201, 81, 94.1, 94.4, 80, 86.8% in Tc-99m-MIBI and 50, 66.7, 88.9, 20, 52.6% in Tc-99m-MDP scan. As a conclusion, Tl-201 scan was the most specific and accurate method for detecting malignant tumor tissue. Tc-99m-MIBI scan was also good for malignant tumor searching. CONCLUSION : With our results, we can use Tl-201 scan to differentiate benign from malignant tumor, and to evaluate the response of preoperative chemotherapy or radiotherapy, and to determine the residual tumor or local recurrence. For the better result, we need to have a more detail information about false positive cases and a more objective and quantitative reading technique.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.5
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• pp.10-24
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• 2007

In the dissertation, a power conversion system for fuel cell is composed of a PWM inverter with LC filter in order to convert fuel cell voltage to a single phase 220[V]. In addition, new insulated DC-DC converters are proposed in order that fuel cell voltage is boosted to 380[V]. In this paper, it requires smaller components than existing converters, which makes easy control. The proposed DC-DC converter controls output power by the adjustment of phase-shift width using switch $S_5\;and\;S_6$ in the secondary switch which provides 93-97[%] efficiency in the wide range of output voltage. Fuel cell simulator is implemented to show similar output characteristics to actual fuel cell. Appropriate dead time td enables soft switching to the range where the peak value of excitation current in a high frequency transformer is in accordance with current in the primary circuit. Moreover, appropriate setting to serial inductance La reduces communication loss arisen at light-load generator and serge voltage arisen at a secondary switch and serial diode. Finally, TMS320C31 board and EPLD using PWM switching technique to act a single phase full-bridge inverter which is planed to make alternating current suitable for household

• Journal of the Korean Society of Clothing and Textiles
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• v.34 no.8
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• pp.1364-1377
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• 2010

Although the human body is a biological subject with definite and distinctive physical features, its actualization and perception differs among societies. The aesthetics of the human body are based on diverse cultural perceptions that must be considered prior to design development. This study establishes the foundations of newly adopted concepts of beauty that are presumed to have been established in the first half of the twentieth century that continue to affect our mindset even now. The research includes human figures in the articles of women's magazines and cosmetic advertisements in the early $20^{th}$ century. The results are as follows: First, the change of perception in the human body: Instead of being a subject of preservation, the body has become a subject of sculpture with emphasis on health in the 1920's and on beauty in the 1930's. The recognition of the importance of the body has created intensive attention on physical training and an increased sense of hygiene. The body exposed to the public perceives itself through the eyes of others that alter one's own perception of oneself as well as become a target of evaluation. There is an additional emphasis on the exotic eroticism of a passive subordinate. Western culture became the standard for modernization along with the dissociation of traditional standards and values. Through the effect of education and western thinking, the awareness of women's rights and self-appreciation was developed. Second, ideal beauty can be summarized as follows: Unprocessed natural beauty was extolled as ideal in the 1920's, but the 1930's, it highlighted big eyes and an aquiline nose that are the characteristics of western women. Taking care of one's appearance was recognized as an important value for every social class. Cosmetics and skin care treatments promised soft and white skin. In contrast to western cosmetics, dark and shiny hair was highly favored. Exercising and traveling, differing seasonal and regional skin treatments were also widely accepted. In its initial stages, the research had originally assumed that the beginning of the twentieth century would be a time in which traditional concepts of beauty and new, westernized aesthetics coexisted. However, as the research progressed, it was clear that the idea of beauty had already adopted occidental ideals by that time. Thus, it seems necessary to continue the study on the shifting paradigms of beauty that must have occurred in the nineteenth and late twentieth century.

• Korean Institute of Interior Design Journal
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• v.19 no.6
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• pp.75-82
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• 2010

The purposes of this study are to present the criteria for a sensibility rating scale for measuring the general public's perception of museums' spatial environment, particularly lobby space, through an empirical analysis; and to clarify the characteristics of the presented rating scale in terms of each rating element and factor. For this study, a survey was conducted during September 11-17, 2010, and a total of 370 museum visitors participated in the survey. A sensibility rating scale used for the survey consisted of a total of 32 adjectives selected from a literature review of previous studies. To specify the dimensions of semantic space using the semantic adjectives, words with opposite meanings were analyzed with the semantic differential technique developed by Osgood et al. Using SPSS, a reliability analysis, factor analysis, and cluster analysis were conducted on the data obtained from the survey. The results of this study can be summarized as follows: According to the general public's perception of museum lobbies, five factors were found from the 19 semantic ratings of the Gyeonggido Museum of Modern Art and the 20 semantic ratings of the Seoul Museum of Art, respectively. In the case of Gyeonggido Museum of Modern Art, three additional semantic words of 'orderly', 'open', and 'original', which did not appear in the case of Seoul Museum of Art, were discovered. In the case of Seoul Museum of Art, more detailed semantic words such as 'restrained', 'ordinary', 'concrete', and 'intellectual (rational)' were obtained. Five semantic elements, which describe the two museums, were: Feelings of 'pleasantness', 'value, 'usage', 'aesthetics', and 'materials'. According to a comparative analysis of the two lobby spaces in terms of semantic rating elements, Gyeonggido Museum of Modern Art was perceived to be an orderly, original, open, soft, and female-like space, whereas Seoul Museum of Art was perceived to be aesthetic, restrained, concrete, realistic, intellectual and rational. In the coming years, the results of this study will serve as valuable data for constructing a sensibility rating scale for evaluating spatial environments of museums.

• Journal of Korean Neurosurgical Society
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• v.29 no.8
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• pp.1024-1029
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• 2000

Objectives : With recent improvements in neuroimaging and the development of third and fourth-generation radiosurgical dose-planning soft ware, came a renewed interest in using radiosurgery for the treatment of movement disorders. Radiosurgery involves no opening of the cranium and no incisions, eliminating both the risk of hemorrhage from passing an electrode to the depths of meningitis from operative infection. It is for these reasons stereotactic radiosurgical treatment of movement disorders has value in a small subgroup of patients. The authors report four cases of Parkinson's disease and one case of dystonia that were treated by Gamma knife. Methods : Radiosurgical nucleus ventralis intermedius thalamotomy using the gamma knife unit was performed to make lesion in two Parkinson's disease patients. A radiation dose of 120Gy was delivered to nucleus using a single 4-mm collimator plug pattern following classic anatomical landmarks. Patients were followed for a median of 10.5 months(range 9-12 months). An independent neurological evaluation of tremor, based on the change in the United Parkinson's Disease Rating Scale tremor score(UPDRS), was correlated with a subjective evaluation. Gamma knife ventrolateral(V.O.P) thalamotomy was performed in one case of dystonia. A central dose of 150Gy was delivered and the patient was followed for 18 months. Gamma knife globus pallidus interna pallidotomy was performed in two Parkinson's disease patients. A radiation dose of 130Gy(range 120-140Gy) was delivered. Patients were followed for a median of 13 months(range 9-14 months). Result : Ventrolateral thalamotomy in dystonia produced regained left hand usage in order to be able to use the telephone. Ventralis intermedius thalamotomy produced an excellent improvement of the tremor in one case, mild improvement of the tremor in the other case of Parkinson's disease. A globus pallidus internalis(GPi) pallidotomy produced improvement of rigidity and dyskinesia : one other showed no change. There were no neurological complications. Conclusion : Gamma Knife thalamotomy considered a safe and effective technique for the treatment of tremor in Parkinson's disease. Although the results from Longer follow-up is not available yet, the short-term results seem to be encouraging.