• Journal of Korean Society of Coastal and Ocean Engineers
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• v.30 no.6
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• pp.319-325
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• 2018

This study conducted an experimental investigation on oscillatory behavior of the hydraulic jump roller. Based on the similarity of the hydraulic jump and tidal bore, the behavior of the front face of hydraulic jump with increasing downstream water depth was studied focusing on profile and fluctuation. In this study, for statistical approach, the ensemble averaging was applied to obtain relevant front profile and compared with the time averaging. The front profile gets mildly sloped and the fluctuation of the starting point of hydraulic jump decreases as the downstream water depth increases.

• Progress in Medical Physics
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• v.31 no.4
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• pp.163-171
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• 2020

Purpose: In this study, the accuracies of electron Monte Carlo (eMC) calculation algorithms were evaluated to determine whether electron beams were modeled by optional air profiles (APs) designed for each applicator size. Methods: Electron beams with the energies of 6, 9, 12, and 16 MeV for VitalBeam (Varian Medical System, Palo Alto, CA, USA) and 6, 9, 12, 16, and 20 MeV for Clinac iX (Varian Medical System) were used. Optional APs were measured at the source-to-detector distance of 95 cm with jaw openings appropriate for each machine, electron beam energy, and applicator size. The measured optional APs were postprocessed and converted into the w2CAD format. Then, the electron beams were modeled and calculated with and without optional APs. Measured profiles, percentage depth doses, penumbras with respect to each machine, and energy were compared to calculated dose distributions. Results: For VitalBeam, the profile differences between the measurement and calculation were reduced by 0.35%, 0.15%, 0.14%, and 0.38% at 6, 9, 12, and 16 MeV, respectively, when the beams were modeled with APs. For Clinac iX, the differences were decreased by 0.16%, -0.31%, 0.94%, 0.42%, and 0.74%, at 6, 9, 12, 16, and 20 MeV, respectively, with the insertion of APs. Of note, no significant improvements in penumbra and percentage depth dose were observed, although the beam models were configured with APs. Conclusions: The accuracy of the eMC calculation can be improved in profiles when electron beams are modeled with optional APs.

• Journal of The Korean Association For Science Education
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• v.21 no.5
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• pp.795-821
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• 2001

This Qualitative study investigated a preservice teacher's developing views of learning with the influence of constructivist epistemology taught in the Math, Science, and Technology Education (MSAT) Master of Education (M. Ed.) preservice teacher education program. The MSAT teacher education program employs constructivist aspects of teacher education and generates applications of constructivism to the practice of teaching, as revealed by faculty interview data. It is important at this point to emphasize that there are significant epistemological and ontological differences between different versions of educational constructivism (i.e., individual, radical, and social constructivism) and that these differences imply different pedagogical practices. For the 16 preservice teachers included in a larger study, the epistemological and ontological characteristics for each teacher's developing views of learning were identified through four in-depth interviews. Data from interviews were used to construct a constructivist profile for each preservice teacher's views of learning (i.e., a profile containing ontological beliefs, epistemological commitments, and pedagogical beliefs). Of the sixteen participants in the larger study, five significantly changed ontological and epistemological beliefs and eleven did not. Profile changes for the five who did change also resulted in changes in their conceptions of science teaching and learning (CSTL). In this article, one of the five teachers case was presented with rich quotes. This case study documents how a preservice teacher transferred his ontological and epistemological beliefs to his pedagogical beliefs and maintained the consistency between his philosophical beliefs and CSTL. It also demonstrated implications that changes in components for an educational constructivist profile have for a preservice teacher's view of himself as teacher. Data indicated the possibility that a constructivist-oriented preservice teacher education program can influence students' conceptions of science teaching and learning by explicitly introducing constructivism as an epistemology rather than as a specific method of instruction. Implications for both instructional practices of teacher education programmes and research are discussed.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.22 no.2
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• pp.174-183
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• 2000

This study was performed to investigate the characteristics of soft tissue profile of the class III malocclusion and to test the yardstick far differential diagnosis between surgical and orthodontic patients. Initial lateral cephalograms of orthodontic group(30 patients) that have acceptable occlusion and profile by orthodontic treatment alone and surgical group(30 patients) that have favorable occlusion and profile by combined surgical-orthodontic treatment were selected in Ajou university hospital. Powell and Burstone II analysis were made on the tracing. Descriptive, comparative, factor, cluster, and discriminant analysis were carried out with computer program. The results were as followings : 1. Patients who received surgery had a more concave profile and a longer lower facial height than patients who received orthodontic treatment alone. 2. Nasolabial angle, ratio of vertical height, and mentolabial sulcus were significantly different at the 5% level. And facial protuberance, upper lip protuberance, mentocervical angle, nasofrontal angle, nasomental angle, mandibular vertical height, angle between cervix and lower face, ratio of mandibular vertical height divided by cervical depth, ratio of vertical height between upper and lower lip, and maxillary protuberance were significantly different at the 1% level. 3. 8 factors were extracted and factor 2, 3, and 8 showed significant differences by factor analysis. 4. Orthodontic group (25) and surgical group (35) were classified by cluster analysis. 5. Discriminant function was D = 0.079Nasomental angle + 0.081Sn-Gn + 3.343Sn-Gn/C-Gn + 1.734Sn-St/St-Me' -26.460, and cutting score was 0, so we can discriminate that orthodontic group has the score above 0, and surgery group below 0. And 91.7% of original grouped cases were correctly classified.

• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.5
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• pp.483-489
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• 2002

The computer simulation has been done for non-insulated and insulated pipes which are vacant or half filled with liquid. The simulation results showed that the density profile on the radiography is continuous and symmetrical around the center of pipe in the case of vacant pipe. On the other hand the density profiles are not symmetrical and depend on geometrical setting for radiography in the case of half filled pipes. Finally, experimental testing on a non-insulated carbon steel pipe with artificial notches of different depth is carried out using Ir-192 and industrial film. Comparing the measured density profile on the radiograph to the calculated one, it has been shown that it is possible to evaluate thickness variation by measuring density profile on a radiograph.

• The Journal of the Acoustical Society of Korea
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• v.34 no.4
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• pp.264-273
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• 2015

Improvement of the radiation beam profile of a medical ultrasonic transducer has been researched in this paper. In order to improve the beam profile, a new transducer structure has been devised that includes both a shaded electrode and a multi-focus lens. For a linear sound source, the beam profile was investigated through finite element analysis, and then the optimal design of the devised structure was carried out by considering such performances as sidelobe level, focal range and beamwidth simultaneously. In the process, the optimal dimension of the devised structure was derived by using the ratio of the focal range to the minimum beamwidth as a performance index. As a result, the beam profile has been improved to have a lower sidelobe level at -20.2 dB and a consistent narrow beamwidth from 30 mm to 160 mm depth with the minimum beamwidth at 2.04 mm. Further, a prototype transducer was fabricated to have the devised structure, and its performance was measured and compared with the analysis results to confirm the validity of the devised transducer structure.

• The Journal of Korea Robotics Society
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• v.18 no.4
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• pp.444-455
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• 2023

In this report, a specialization plan for wearable robots by mission profile was investigated and analyzed to derive an application plan. The final goal of this study was to derive the operating requirements of wearable robots according to specialized plans, and to conduct a specialized study on wearable robots by mission profile through investigation/analysis of specialized plans for each mission profile. In the study, 1) Research on technology trends related to military wearable robots such as patents and papers, 2) Research/analysis of mission profiles to characterize wearable robots, 3) Analysis of wearable robot specialization plans according to mission profiles, and 4) Requirements for wearable robot operation were derived. In the first time of the study, a survey on technology trends related to wearable robots for soldiers such as patents and papers was completed, and a military consultative body was conducted to derive measures to characterize wearable robots. In addition, a survey was conducted on mission profiles, and the second time study derived Key Performance Parameters (KPP) for operational performance, core performance, and system performance based on scenarios by mission profile. However, it is revealed that the KPP derived from the research results was not covered in this paper because it was judged that more in-depth research was needed prior to disclosure. In order to prepare for future battlefield situations and increase the usability of wearable robots, this study was conducted to characterize wearable robots by considering the characteristics of soldiers' equipment according to mission profiles and to characterize wearable robots by mission profile.

• Journal of Radiation Protection and Research
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• v.41 no.2
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• pp.173-178
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• 2016

Background: In situ gamma spectrometry has been used to measure environmental radiation, assumptions are usually made about the depth distribution of the radionuclides of interest in the soil. The main limitation of in situ gamma spectrometry lies in determining the depth distribution of radionuclides. The objective of this study is to develop a method for subsurface characterization by in situ measurement. Materials and Methods: The peak to valley method based on the ratio of counting rate between the photoelectric peak and Compton region was applied to identify the depth distribution. The peak to valley method could be applied to establish the relation between the spectrally derived coefficients (Q) with relaxation mass per unit area (${\beta}$) for various depth distribution in soil. The in situ measurement results were verified by MCNP simulation and calculated correlation equation. In order to compare the depth distributions and contamination levels in decommissioning KRR site, in situ measurement and sampling results were compared. Results and Discussion: The in situ measurement results and MCNP simulation results show a good correlation for laboratory measurement. The simulation relationship between Q and source burial for the source layers have exponential relationship for a variety depth distributions. We applied the peak to valley method to contaminated decommissioning KRR site to determine a depth distribution and initial activity without sampling. The observed results has a good correlation, relative error between in situ measurement with sampling result is around 7% for depth distribution and 4% for initial activity. Conclusion: In this study, the vertical activity distribution and initial activity of $^{137}Cs$ could be identifying directly through in situ measurement. Therefore, the peak to valley method demonstrated good potential for assessment of the residual radioactivity for site remediation in decommissioning and contaminated site.

• Proceedings of the Korean Vacuum Society Conference
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• 1992.02a
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• pp.17-18
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• 1992

SIMS is an indispensable surface analysis instrument in trace element depth p profiling because of high detection sensitivity and excellent depth r resolution, however, it requires standard sample to do quantitative analysis d due to matrix effect depending on the species of impurities and sample m matricies and on the sputtering rates. A Among the SNMS technology developed to supply the deficiency, we researched i into CsX+ SNMS which improved the resul t quanti tati vely wi thout any extra epuipments. So basic SNMS functions were confirmed through matrix element composition rate a analysis using Si02 layer etc. and adaptability to trace element c concentration analysis was tried. For that purpose we compared SIMS depth profile data for Boron which presented s strong matrix effect on account of Fluorin existence after BF2 ion implantation on silicon substrate with SNMS data. d dynamic range were investigated. A After these experements we concluded that CsX+ SNMS reduced matrix effect and we could apply it to profile impurity elements.

• Journal of the Korean Vacuum Society
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• v.1 no.1
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• pp.115-120
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• 1992

SIMS is an indispensable surface analysis instrument in trace element depth profiling because of high detection sensitivity and excellent depth resolution, however, it requires a standard sample to do quantitative analysis due to matrix effect depending on the species of impurities and sample matricies and on the sputtering rates. Among the SNMS technology developed to supply the deficiency, we researched into CsX+ SNMS which improved the result quantitatively without any extra epuipments. So basic SNMS functions were confirmed through matrix element composition rate analysis using Siq layer etc., and adaptability to trace element concentration alaysis was tried. For that purpose we compared SIMS depth profile data for Boron which presented strong matrix effect on account of Fluorin existence after BF2 ion implantation on silicon substrate with SNMS data. Also detection limit and dynamic range were investigated. After these experements we concluded that CsX+ SNMS reduced matrix effect and we could apply it to profile impurity elements.