• Journal of the Korean Geotechnical Society
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• 제23권12호
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• pp.33-42
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• 2007

The assessment of shear wave velocity($V_s$) in soft soils is extremely difficult due to the soil disturbances during sampling and field access. After a ring type field $V_s$ probe(FVP) has been developed, it has been applied at the southern coastal area of the Korean peninsular. This study presents the upgraded FVP "blade type FVP", which minimizes soil disturbance during penetration. Design concerns of the blade type FVP include the tip shape, soil disturbance, transducers, protection of the cables, and the electromagnetic coupling between transducers and cables. The cross-talking between cables is removed by grouping and extra grounding of the cables. The shear wave velocity of the FVP is simply calculated by using the travel distance and the first arrival time. The large calibration chamber tests are carried out to investigate the disturbance effect due to the penetration of FVP blade and the validity of the shear waves measured by the FVP. The blade type FVP is tested in soils up to 30m in depth. The shear wave velocity is measured every 10cm. This study suggests that the upgraded blade type FVP may be an effective device for measuring the shear wave velocity with minimized soil disturbance in the field.

• The Journal of the Korea Contents Association
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• 제10권3호
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• pp.204-214
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• 2010

This research was intended to provide a basic data on the study of utilization of assistive technology to improve vocational ability for people with intellectual disabilities. As this study was literature review, it was analyzed the qualitative level, methodology contents, and general characteristic of a study, related assistive technology application for improvement of vocational ability in people with intellectual disabilities. The results of this study were as follows; Firstly, experimental environments mostly consisted of separated experimental conditions and design employed multiple probe design; Secondly, all of studies were involved in the standard of selection of subjects, but the proportions of study describing the contents related to subjects was low. The proportions of study describing the behavior-control and exterior-variable control method was low; Thirdly, most study evaluated independent variable and presented fidelity of treatment but, the presentation of social validity was proved to be insufficient. In order to effective application of assistive technology in vocational rehabilitation, it is need a evidence that the application of assistive technology is evidence-based practice in vocational rehabilitation. We also need a supplementation between methodology contents and qualitative level of study in more study.

• Communications of Mathematical Education
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• 제19권4호
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• pp.733-767
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• 2005

During the past decades, there has been a fundamental change in the objectives and nature of mathematics education, as well as a shift in research paradigms. The changes in mathematics education emphasize learning mathematics from realistic situations, students' invention or construction solution procedures, and interaction with other students of the teacher. This shifted perspective has many similarities with the theoretical . perspective of Realistic Mathematics Education (RME) developed by Freudental. The RME theory focused the guide reinvention through mathematizing and takes into account students' informal solution strategies and interpretation through experientially real context problems. The heart of this reinvention process involves mathematizing activities in problem situations that are experientially real to students. It is important to note that reinvention in a collective, as well as individual activity, in which whole-class discussions centering on conjecture, explanation, and justification play a crucial role. The overall purpose of this study is to examine the developmental research efforts to adpat the instructional design perspective of RME to the teaching and learning of differential equation is collegiate mathematics education. Informed by the instructional design theory of RME and capitalizes on the potential technology to incorporate qualitative and numerical approaches, this study offers as approach for conceptualizing the learning and teaching of differential equation that is different from the traditional approach. Data were collected through participatory observation in a differential equations course at a university through a fall semester in 2003. All class sessions were video recorded and transcribed for later detailed analysis. Interviews were conducted systematically to probe the students' conceptual understanding and problem solving of differential equations. All the interviews were video recorded. In addition, students' works such as exams, journals and worksheets were collected for supplement the analysis of data from class observation and interview. Informed by the instructional design theory of RME, theoretical perspectives on emerging analyses of student thinking, this paper outlines an approach for conceptualizing inquiry-oriented differential equations that is different from traditional approaches and current reform efforts. One way of the wars in which thus approach complements current reform-oriented approaches 10 differential equations centers on a particular principled approach to mathematization. The findings of this research will provide insights into the role of the mathematics teacher, instructional materials, and technology, which will provide mathematics educators and instructional designers with new ways of thinking about their educational practice and new ways to foster students' mathematical justifications and ultimately improvement of educational practice in mathematics classes.

• Journal of Life Science
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• 제21권8호
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• pp.1083-1093
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• 2011

A microorganism utilizing rice hulls as a substrate for the production of carboxymethylcellulase (CMCase) was isolated from seawater and identified as Bacillus lincheniformis by analyses of its 16S rDNA sequences. The optimal carbon and nitrogen sources for production of CMCase were found to be rice hulls and ammonium nitrate. The optimal conditions for cell growth and the production of CMCase by B. lincheniformis LBH-52 were investigated using the response surface method (RSM). The analysis of variance (ANOVA) of results from central composite design (CCD) indicated that a highly significant factor ("probe>F" less than 0.0001) for cell growth was rice hulls, whereas those for production of CMCase were rice hulls and initial pH of the medium. The optimal conditions of rice hulls, ammonium nitrate, initial pH, and temperature for cell growth extracted by Design Expert Software were 48.7 g/l, 1.8 g/l, 6.6, and 35.7$^{\circ}C$, respectively, whereas those for the production of CMCase were 43.2 g/l, 1.1 g/l, 6.8, and 35.7$^{\circ}C$. The maximal production of CMCase by B. lincheniformis LBH-52 from rice hulls under optimized conditions was 79.6 U/ml in a 7 l bioreactor. In this study, rice hulls and ammonium nitrate were developed to be substrates for the production of CMCase by a newly isolated marine microorganism, and the time for production of CMCase was reduced to 3 days using a bacterial strain with submerged fermentation.

• Journal of the Korean Society of Propulsion Engineers
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• 제21권3호
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• pp.49-55
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• 2017

In this study, gas turbine engine inlet duct was designed to satisfy uniform flow at aerodynamic interface plane (AIP). Haack-series was selected as nose cone profile and duct outer radius($r_o$) was designed to satisfy to match with area change rate between the nose cone and outer duct wall by the 1-D sizing. The design object of the inlet duct wall profile which has the gradual area change rate was uniform Mach number in the core flow region and minimum boundary later thickness at the both inner nose wall and outer duct wall. The flow characteristics inside the inlet duct was evaluated using CFD. The static pressure distribution at the AIP showed uniform pattern within 0.16%. Based on Mach number profile, the boundary layer thickness was 2% of channel height. Kiel temperature rake location was decided less than 100 mm in front of nose cone where the Mach number is less than 0.1 in order to maximize the temperature probe recovery rate.

• 재활복지
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• 제20권4호
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• pp.203-228
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• 2016

The purpose of this study was to find out the recent trend of high-tech AAC intervention studies for individuals with disabilities. Electronic database searches were completed to identify studies published between 2009 and 2016. 46 studies were identified for inclusion in this review. The studies were classified as participants, research design, intervention settings, independent variables, dependent variables, communication skills by High-tech device, type of high-tech AAC device. Across these studies, intervention was provided to total of 126 participants. Most participants are aged 6-11 and the most common diagnosis was autistic spectrum disorder. Most common study designs were multiple probe design and multiple treatment design. The majority of studies implemented interventions in a special education school(classroom) setting. The majority of studies implemented interventions to compare the effect of high-tech and low-tech AAC device interventions. The majority of targeted behavioral outcomes were communication skills. Tablet PC was the most frequently used for intervention in both domestic and foreign studies. The most common softwares were 'My talky' in domestic studies and 'Proloquo2Go' in foreign studies. The synthesis of evidence describing views of users and providers and the implementation of high-tech AAC device can provide valuable data to inform intervention studies and functional outcome measures. Suggestions for the future research are discussed.

• Women's Health Nursing
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• 제9권3호
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• pp.277-286
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• 2003

Purpose: The purpose of this study was to probe the effect of foot reflexology education program on nursing students with constipation, anxiety and depression. This study was a quasi-experimental study of pre-test and posttest design on non-equivalent control group. Method: The data of this study were collected from October 28, to December 14, 2002. The subjects consisted of 61 nursing students (experimental group: 31, control group: 30) with constipation, anxiety and depression. 31 out of them were devided into the experimental group and received foot reflexology education program that was authorized by the World Foot Reflexology Association and made to suit for the subjects by the author for 6weeks composed of 2 weeks theory and of 4 weeks practical skill on the program. The effect of the program was measured by Bowel Function Assessment Form for constipation, State Anxiety Inventory, and Beck Depression Inventory. Data were analyzed by t-test, $x^2$-test, Repeated measures ANOVA, Bonferroni multiple comparison using SAS/PC 8.12 program. Result: After all session of treatment, the score of bowel function assessment were significantly decreased in the experimental group compared to the control group. Outcomes of 6 and 7 weeks were significantly different from those of pre-experiment. After all session of treatment, anxiety states were significantly decreased in the experimental group compared to the control group. Outcomes of 7 weeks were significantly different from those of pre-experiment. After all session of treatment, depression states were significantly decreased in the experimental group compared to the control group. Outcomes of 6 and 7 weeks were significantly different from those of pre- experiment. Conclusion: The results are suggested that the foot reflexology education program might improve the bowel function, anxiety and depression for the nursing students with constipation, anxiety and depression.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• 제22권12호
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• pp.1116-1123
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• 2011

In this paper, we studied the propagation of the radio wave in the human body for WBAN system and proposed the path-loss models applicable in the MICS and ISM frequency band. Human Tissues are composed of complicate organ. So it is difficult to measure to insert the probe in human body. Accordingly, the equations were modelled by electromagnetic analysis using the numerical phantom based on the real human. The numerical analysis used XFDTD 6.5 of Remcom co. in commercial software based on the Finite-Difference Time-Domain method. Human body model used a standard adult Korean model developed by ETRI. The proposed channel models will be very helpful to design the WBAN system.

• Advances in aircraft and spacecraft science
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• 제4권6호
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• pp.729-744
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• 2017

This investigation highlights rationale of electrically conductive nano adhesives for its essential application for Electromagnetic Interference (EMI) Shielding in satellites and Lightning Strike Protection in aircrafts. Carbon Nano Fibres (CNF) were functionalized by electroless process using Tollen's reagent and by Plasma Enhanced Chemical Vapour Deposition (PECVD) process by depositing silver on CNF. Different weight percentage of CNF and silver coated CNF were reinforced into the epoxy resin hardener system. Scanning Electron Microscopy (SEM) micrographs clearly show the presence of CNF in the epoxy matrix, thus giving enough evidence to show that dispersion is uniform. Transmission Electron Microscopy (TEM) studies reveal that there is uniform deposition of silver on CNF resulting in significant improvement in interfacial adhesion with epoxy matrix. There is a considerable increase in thermal stability of the conductive nano adhesive demonstrated by Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). Four probe conductivity meters clearly shows a substantial increase in the electrical conductivity of silver coated CNF-epoxy composite compared to non-coated CNF-epoxy composite. Tensile test results clearly show that there is a significant increase in the tensile strength of silver coated CNF-composites compared to non-coated CNF-epoxy composites. Consequently, this technology is highly desirable for satellites and EMI Shielding and will open a new dimension in space research.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• 제16권6호
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• pp.632-643
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• 2005

This paper presents a folded stripline-fed small broadband disk-loaded monopole antenna with vertical ground plane. The bandwidth of the proposed antenna can be enhanced by electromagnetic coupling between the shorted rectangular disk and the probe with folded strip line. The measured impedance bandwidth of the proposed antenna is $37.6\%$ for $VSWR\leq2$ with the center frequency at 2.313 GHz and has the physical dimensions of only $11mm\times11mm\times11mm$ which corresponds to the electrical length of $0.085\lambda_0\times0.085\lambda_0\times0.085\lambda_0$. For improving the radiation pattern characteristics, rectangular slits are inserted in the vertical ground plane. Rectangular slits affect the currents distribution on the ground plane, so that the antenna radiation in the direction of the ground plane is reduced more than 3 dBi. Gain of the antenna is approximately 2.6 dBi within the bandwidth.