• Journal of Radiation Protection and Research
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• v.30 no.1
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• pp.17-25
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• 2005

Since the safety of nuclear power plant has been becoming a big social issue the exposure dose of radiation for workers has been one of the important factors concerning the safety problem. The existing calculation methods of radiation dose used in the planning of radiation work assume that dose rate does not depend on the location within a work space thus the variation of exposure dose by different work path is not considered. In this study, a modified numerical method was presented to estimate the exposure dose during radiation work in radwaste storage considering the effects of the distance between a worker and sources. And a new numerical algorithm was suggested to search the optimal work path minimizing the exposure dose in pre-defined work space with given radiation sources. Finally, a virtual work simulation program was developed to visualize the exposure dose of radiation doting radiation works in radwaste storage and provide the capability of simulation for work planning. As a numerical example, a test radiation work was simulated under given space and two radiation sources, and the suggested optimal work path was compared with three predefined work paths. The optimal work path obtained in the study could reduce the exposure dose for the given test work. Based on the results, tile developed numerical method and simulation program could be useful tools in the planning of radiation work.

• Archives of design research
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• v.19 no.2 s.64
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• pp.163-172
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• 2006

Sign is one of the important factors in city and national image formation, thus requires high level of quality. However, domestic sign emphasize only the sense of attention that leads to big sized signs, thus often results in a poor coordination with the surrounding space. This situation requires employees in sign business want to learn specialized knowledge about design field. Based on these circumstances, we propose sign design software to employees in sign business field as an aid tool that can help to develop good signs in terms of functionality as well as harmony of design. Thus, in this investigation, sign simulation software application case that can design sign and apply this sign to the actual application site is presented. In order to develop this software, literature survey and preliminary studies were performed to analyze the preparation process and environment, and designed sign design element and software elements, user interrace, and finally Java software were utilized. This developed software can be used as a textbook in sign design related departments in schools, and hopefully to enhance the social recognition of sign as well as academic interest.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.73-73
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• 2000

안티퓨즈 소자는 프로그램 가능한 절연층의 상하 각각에 금속층이나 다결정 실리콘 등의 전도 가능한 전극으로 구성된다. 프로그램은 상하 전극간에 임계전압을 가했을 때 일어나게 되며 이때 절연층이 파괴되므로 비가역적이어서 재사용은 불가능하게 된다. 안티퓨즈 소자는 이러한 프로그램 특성으로 인하여 메모리 소자를 이용한 스위치 보다 속도나 집적도 면에서 우수하다. FPGAsdp 사용되는 안티퓨즈 소자는 집적도의 향상과 적정 절열파괴전압 구현을 위해 절연막의 두께를 감소시키는 것이 바람직하다. 그러나 두께나 감소될 경우 바닥전극의 hillock에 큰 영향을 받게 되며, 그로 인해 절연막의 두께를 감소시키는 것는 한계가 있는 것으로 보고되어 있다. 본 논문에서는 낮은 구동 전압에서 동작하고 안정된 on/pff 상태를 갖는 Al/TiO2-SiO2/Mo 형태의 안티퓨즈 소자를 제안하였다. 만들어진 antifuse cell은 0.6cm2 크기로 약 300개의 샘플을 제작하여 측정하였다. 비저항이 6-9 $\Omega$-cm인 P형의 실리콘 웨이퍼에 RF 마그네트론 스퍼터링(RF magnetron sputtering) 방법으로 하부전극인 Mo를 3000 증착하였다. SiO2는 안티퓨즈에서 완충막의 역할을 하며 구조적으로 antifuse cell을 완전히 감싸고 있는 형태로 제작되었다. 완충막 구조를 만들기 dln해 일반적인 포토리소그라피(Photo-lithography)작업을 거처 형성하였다. 형성된 hole의 크기는 5$mu extrm{m}$$\times$5$\mu\textrm{m}$ 이었다. 완충막이 형성된 기판위에 안티퓨즈 절연체인 SiO2를 PECVD 방식으로 100 증착하였다. 그 후 이중 절연막을 형성시키기 위해 LPCVD를 이용하여 TiO2를 150 증착시켰다. 상부 전극은 thermal evaporation 방식으로 Al을 250nm 증착하여Tejk. 하부전극으로 사용된 Mo 금속은 표면상태가 부드럽고 녹는점이 높은 매우 안정된 금속으로, 표면위에 제조된 SiO2의 특성을 매우 안정되게 유지시켰다. 제안된 안티푸즈는 이중절연막을 증착함으로서 전체적인 절연막의 두께를 증가시켜 바닥전극의 hillock의 영향을 적게 받아 안정성을 유지할 수 있도록 하였다. 또한, 두 절연막 사이의 계면 반응에 의해 SiO2 막을 약화시켜 절연막의 두께가 두꺼워졌음에도 기존의 SiO2 절연막의 절연 파괴 전압 및 누설 전류오 비교되는 특성을 가졌다. 이중막을 구성하고 있는 안티퓨즈의 ON-저항이 단일막과 비교해 비슷한 것을 볼 수 잇는데, 그 이유는 TiO2에 포함된 Ti가 필라멘트에 포함되어 있어 필라멘트의 저항을 감소시켰기 때문으로 사료된다. 결국 이중막을 구성시 ON-저항 증가에 의한 속도 저하 요인은 없다고 할 수 있다. 5V의 절연파괴 시간을 측정한느 TDDB 테스트 결과 1.1$\times$103 year로 기대수치인 수십 년보다 높아 제안된 안티퓨즈의 신뢰성을 확보 할 수 있었다. 제안된 안티퓨즈의 이중 절연막의 두께는 250 이고 프로그래밍 전압은 9.0V이고, 약 65$\Omega$의 on 저항을 얻을수 있었다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.5
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• pp.627-635
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• 2019

A programmable drone is a drone developed not only to experience the basic principles of flight but also to control drones through Arduino-based programming. Due to the nature of the training drones, the main users are students who are inexperienced in controlling the drones, which often cause frequent collisions with external objects, resulting in high damage to the drones' frame. In this study, the structural stability of the drone was evaluated by means of a structural dynamics based collision simulation for educational drone frame. Collision simulations were performed on three cases according to the impact angle of $0^{\circ}$, $+15^{\circ}$ and $-15^{\circ}$, using an analytical model with approximately 240,000 tetrahedron elements. Using ANSYS LS-DYNA, which provides excellent functions for the simulation of the dynamic behavior of three-dimensional structures, the stress distribution and strain generated on the drone upper, the drone lower, and the ring assembly were analyzed when the drones collided against the wall at a rate of 4 m/s. Safety factors resulting from the equivalent stress and the yield strain were calculated in the range of 0.72 to 2.64 and 1.72 to 26.67, respectively. To ensure structural stability for areas where stress exceeds yield strain and ultimate strain according to material properties, the design reinforcement is presented.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.6
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• pp.583-592
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• 2020

This study assessed source depletion in the vadose zones of contaminated sites. The possible range of infiltration rate in Korea was statistically analyzed. The results showed a trend of decreasing leachate concentration of 13 pollutants used for risk assessment. Among them, benzene, ethylbenzene, toluene, and xylene showed a lower leachate concentration in groundwater over time due to their low distribution coefficient and also possible biodegradation effects. The average values of the relative concentration could be taken as a default index due to a very small range of uncertainties. In the case of heavy metals, it was shown that the leachate concentration in a pollutant does not decrease over time. Considering the annually different infiltration, a site-specific source-depletion scenario was applied to Cheongju in North Chungcheong Province. The result was expressed as a time series of the relative concentration of the leachate concentration, and this was compared to the trend by averaged Korean infiltration. Finally, an open-source code that used Python was used to help calculate the leachate concentration by this site-specific infiltration scenario.

• Science of Emotion and Sensibility
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• v.25 no.1
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• pp.67-78
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• 2022

Interest in bio-signal monitoring of wearable devices is increasing significantly as the next generation needs to develop new devices to dominate the global market of the information and communication technology industry. Accordingly, this research developed a resistive textile strain sensor through a wetting process in a single-wall carbon nanotube dispersion solution using an E-Band with low hysteresis. To measure the resistance signal in the E-Band to which electrical conductivity is applied, a universal material tester, an Arduino, and LCR meters that are microcontroller units were used to measure the resistance change according to the tensile change. To effectively handle various noises generated due to the characteristics of the fabric textile strain sensor, the filter performance of the sensor was evaluated using the moving average filter, Savitsky-Golay filter, and intermediate filters of signal processing. As a result, the reliability of the filtering result of the moving average filter was at least 89.82% with a maximum of 97.87%, and moving average filtering was suitable as the noise filtering method of the textile strain sensor.

• Journal of Korean Library and Information Science Society
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• v.54 no.4
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• pp.307-334
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• 2023

The purpose of this study is to examine the status of data librarian-related course syllabi in the 2023 American Library Association(ALA)-accredited degree programs in Library and Information Science (LIS). The present study examined LIS course syllabi related to data librarian including course titles, course objectives, course descriptions, weekly topics and assignments. ALA-accredited LIS programs offer various courses in data librarianship such as data management and curation, data analysis and visualization, metadata, information services, research methods, library management, academic libraries, computer programming and databases. This study collected 184 syllabi from the ALA-accredited LIS programs and selected and analyzed 127 syllabi that are related to data librarianship. The study examined 3,045 course titles, 2,559 course description from 61 LIS degree programs overseas, and 1,330 course titles from 37 LIS degree programs in Korea. This study found that LIS degree programs both in Korea and overseas offer various courses for data librarians. The researcher hopes the findings of this study will be used as a starting point to develop or redesign courses related to data librarianship in the information field.

• Information Systems Review
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• v.21 no.2
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• pp.117-137
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• 2019

In the Big Data era, data science has become popular with the production of numerous data in various domains, and the power of data has become a competitive power. There is a growing interest in unstructured data, which accounts for more than 80% of the world's data. Along with the everyday use of social media, most of the unstructured data is in the form of text data and plays an important role in various areas such as marketing, finance, and distribution. However, text mining using social media is difficult to access and difficult to use compared to data mining using numerical data. Thus, this study aims to develop Korean Natural Language Application (KoALA) as an integrated application for easy and handy social media text mining without relying on programming language or high-level hardware or solution. KoALA is a specialized application for social media text mining. It is an integrated application that can analyze both Korean and English. KoALA handles the entire process from data collection to preprocessing, analysis and visualization. This paper describes the process of designing, implementing, and applying KoALA applications using the design science methodology. Lastly, we will discuss practical use of KoALA through a block-chain business case. Through this paper, we hope to popularize social media text mining and utilize it for practical and academic use in various domains.

• Progress in Medical Physics
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• v.12 no.1
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• pp.41-50
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• 2001

The quantification analysis of renal scintigraphy is strongly affected by the location, shape and size of region of interest(ROI). When ROIs are drawn manually, these ROIs are not reproducible due to the operators' subjective point of view, and may lead to inconsistent results even if the same data were analyzed. In this study, the effect of the ROI variation on the analysis of renal scintigraphy when the ROIs are drawn manually was investigated, and in order to obtain more consistent results, methods for automated ROI definition were developed and the results from the application of the developed methods were analyzed. Relative renal function, glomerular filtration rate and mean transit time were selected as clinical parameters for the analysis of the effect of ROI and the analysis tools were designed with the programming language of IDL5.2. To obtain renal scintigraphy, $^{99m}$Tc-DTPA was injected to the 11 adults of normal condition and to study the inter-operator variability, 9 researchers executed the analyses. The calculation of threshold using the gradient value of pixels and border tracing technique were used to define renal ROI and then the background ROI and aorta ROI were defined automatically considering anatomical information and pixel value. The automatic methods to define renal ROI were classified to 4 groups according to the exclusion of operator's subjectiveness. These automatic methods reduced the inter-operator variability remarkably in comparison with manual method and proved the effective tool to obtain reasonable and consistent results in analyzing the renal scintigraphy quantitatively.

• Journal of Radiation Protection and Research
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• v.33 no.2
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• pp.47-51
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• 2008

Objective: This study analyzed errors due to rotation or tilt of the magnetic resonance (MR) imaging indicator during image acquisition for a stereotactic radiosurgery. The error correction procedure of a commercially available stereotactic neurosurgery treatment planning program has been verified. Materials and Methods: Software virtual phantoms were built with stereotactic images generated by a commercial programming language, Interactive Data Language (version 5.5). The thickness of an image slice was 0.5 mm, pixel size was $0.5{\times}0.5mm$, field of view was 256 mm, and image resolution was $512{\times}512$. The images were generated under the DICOM 3.0 standard in order to be used with Leksell GammaPlan$^{(R)}$. For the verification of the rotation error correction function of Leksell GammaPlan$^{(R)}$, 45 measurement points were arranged in five axial planes. On each axial plane, there were nine measurement points along a square of length 100 mm. The center of the square was located on the z-axis and a measurement point was on the z-axis, too. Five axial planes were placed at z=-50.0, -30.0, 0.0, 30.0, 50.0 mm, respectively. The virtual phantom was rotated by $3^{\circ}$ around one of x, y, and z-axis. It was also rotated by $3^{\circ}$ around two axes of x, y, and z-axis, and rotated by $3^{\circ}$ along all three axes. The errors in the position of rotated measurement points were measured with Leksell GammaPlan$^{(R)}$ and the correction function was verified. Results: The image registration errors of the virtual phantom images was $0.1{\pm}0.1mm$ and it was within the requirement of stereotactic images. The maximum theoretical errors in position of measurement points were 2.6 mm for a rotation around one axis, 3.7 mm for a rotation around two axes, and 4.5 mm for a rotation around three axes. The measured errors in position was $0.1{\pm}0.1mm$ for a rotation around single axis, $0.2{\pm}0.2mm$ for double and triple axes. These small errors verified that the rotation error correction function of Leksell GammaPlan$^{(R)}$ is working fine. Conclusion: A virtual phantom was built to verify software functions of stereotactic neurosurgery treatment planning program. The error correction function of a commercial treatment planning program worked within nominal error range. The virtual phantom of this study can be applied in many other fields to verify various functions of treatment planning programs.