• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.5
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• pp.919-939
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• 2021

As a next-generation communication technology, 5G networks are capable of handling large amounts of traffic based on higher speeds, shorter communication delays, and higher connectivity compared to 4G networks. In this 5G network environment, base stations are installed all over the city at high density due to their characteristics, and are connected to user terminals to provide services. Therefore, if the base station is damaged by a malicious attacker, it is expected to cause great damage to users and society as a whole. So the need for secure communication equipment such as 5G base stations has emerged. Therefore, in this paper, we propose the security functional requirements derived using threat modeling, a systematic methodology for 5G base stations, and the security assurance requirements at the level that can cope with the backdoor issues. The security requirements proposed in this paper can be used for base station design and development to construct a secure network environment as a security evaluation standard for 5G base stations.

• The Journal of Korean Society for Radiation Therapy
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• v.31 no.1
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• pp.17-24
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• 2019

Purpose: The present study aims to assess the level of coherency and the accuracy of Point dose of the Isocenter of VERO, a linear accelerator developed for the purpose of the Stereotactic Body Radiation Therapy(SBRT). Materials and Method: The study was conducted randomly with 10 treatment plans among SBRT patients in Kyungpook National University Chilgok Hospital, using VERO, a linear accelerator between June and December, 2018. In order to assess the equipment's power stability level, we measured the output constancy by using PTW-LinaCheck, an output detector. We also attempted to measure the level of accuracy of the equipment's Laser, kV(Kilo Voltage) imaging System, and MV(Mega Voltage) Beam by using Tofu Phantom(BrainLab, Germany) to assess the accuracy level of geometrical Isocenter. We conducted a comparative analysis to assess the accuracy level of the dose by using an acrylic Phantom($30{\times}30{\times}20cm$), a calibrated ion chamber CC-01(IBA Dosimetry), and an Electrometer(IBA, Dosimetry). Results: The output uniformity of VERO was calculated to be 0.66 %. As for geometrical Isocenter accuracy, we analyzed the error values of ball Isocenter of inner Phantom, and the results showed a maximum of 0.4 mm, a minimum of 0.0 mm, and an average of 0.28 mm on X-axis, and a maximum of -0.4 mm, a minimum of 0.0 mm, and an average of -0.24 mm on Y-axis. A comparison and evaluation of the treatment plan dose with the actual measured dose resulted in a maximum of 0.97 % and a minimum of 0.08 %. Conclusion: The equipment's average output dose was calculated to be 0.66 %, meeting the ${\pm}3%$ tolerance, which was considered as a much uniform fashion. As for the accuracy assessment of the geometric Isocenter, the results met the recommended criteria of ${\pm}1mm$ tolerance, affirming a high level of reproducibility of the patient's posture. The difference between the treatment plan dose and the actual measurement dose was calculated to be 0.52 % on average, significantly less than the 3 % tolerance, confirming that it obtained predicted does. The current study suggested that VERO equipment is suitable for SBRT, and would result in notable therapeutic effect.

• International Journal of Highway Engineering
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• v.13 no.2
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• pp.1-8
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• 2011

The objective of this paper is to evaluate the performance of low $CO_2$ asphalt binder properties using LEADCAP$^{(R)}$(Low Energy and Carbon Asphalt Pavement) additive as function of various aging methods such as RTFO(Rolling thin film oven), Ultraviolet(UV) lay. In order to simulate the short-term aging of asphalt binder that occurs during the hot-mixing asphalt process, the Rolling Thin Film Oven(RTFO) was used. Asphalt binder using LEADCAP$^{(R)}$ is prepared by addition of a photoinitiator activated by ultraviolet lay. The mechanical and rheological properties of the asphalt binder were estimated using UTM(Universal Testing Machine) and DSR(Dynamic Shear Rheometer). The test results showed that the asphalt binder using LEADCAP$^{(R)}$ additive was improved the rutting resistance at testing temperature ($70^{\circ}C$) and increased tensile strength at low temperature. Also, Thermal analysis shows that the Melting Point(Tm) of asphalt binder using LEADCAP$^{(R)}$ additive was constant although the asphalt binder was aged by Ultraviolet.

• Journal of Biomedical Engineering Research
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• v.23 no.5
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• pp.397-403
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• 2002

Urine glucose monitoring system is a self-monitoring system that display the glucose level by non-invasive measurement method. In this paper, We developed a noninvasive urine glucose monitoring system that improved defects of urine glucose measurement with a colorimeter method and invasive blood glucose measurement method. This system consist of bio-chemical sensor for urine glucose measurements, signal detecting part, digital and signal analysis part, display part and power supplying part. The developed bio-chemical sensor for the measurement of urine glucose has good reproducibility, convenience of handing and can be mass-produced with cheap price. To evaluate the performance of the developed system, We performed the evaluation of confidence about the detection of glucose level by a comparison between a standard instrument in measuring glucose level and the developed system using standard glucose solutions mixed with urine. Standard error was 2.85282 from the evaluation of confidence based on regression analysis. Also, In analysis of S.D(standard deviation) and C.V(coefficient of validation) that are important parameters to evaluate system using bio-chemical sensor, S.D was 10% which falls under clinically valid value, 15%, and C.V was under 5%. Consequently from the above results, compared to blood glucose measurement, the system performance is satisfactory.

• Journal of the Society of Disaster Information
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• v.18 no.2
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• pp.395-404
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• 2022

Purpose: Small-scale construction sites have insufficient systematic safety management activities, and due to the characteristics of the construction site, the production structure is complex due to external environmental factors, and the risk of construction equipment is very high. We would like to propose a checklist method among practical risk assessment techniques that can derive risk factors for disaster prevention at small construction sites and reduce disasters. Method: Risk factors were derived by analyzing literature research and disaster cases, and detailed work for a checklist of risk assessment suitable for small-scale construction sites was classified based on risk factor items. Result: Hazard factors were divided into 6 major categories, and 29 detailed types of work were classified based on actual work types, and 80 detailed works were classified accordingly. Conclusion: By arranging risk factors suitable for small-scale construction sites according to the classification system, the lack of expertise in the construction site can be supplemented, and risk factors can be derived more easily and disaster reduction can be expected through establishment of safety measures.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.433-438
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• 2005

This study was carried out to analyze the effect of the variation of a wind speed on the stability of a container crane. The wind load according to 'The Requirement of Port Facilities and Equipments / Specification for the design of crane structures (KS A 1627)' and 'Load Criteria of Structures' enacted by the ministry of construction & transportation was evaluated. And the uplift forces of a container crane under this wind load were calculated by analyzing reaction forces at each supporting point and compared with each other. The analytic model was a container crane with uplift capacity of 50ton which was widely used in port.

• Spatial Information Research
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• v.13 no.1 s.32
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• pp.55-63
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• 2005

Direct Georeferencing(DG) Is based on the direct measurement of the projection centers and rotation angle of sensor through loading the GPS and INS in aircraft. The methods can offer us to acquire the exterior orientation parameters with only minimum GCPs, even the ground control process could be completely skipped. Hence, as long as securing Digital Elevation Model (DEM), it is feasible to generate digital orthophotos without performing the aerial triangulation with Ground Control Point (GCP) surveying. In this study, the DEM is automatically generated by using a image matching technique based on aerial photos and exterior orientation parameters. This is followed by producing an orthophoto from these results. Finally, accuracy analysis of the georeferencing technique for generating orthoimage indicates that RMS errors of 62cm and 76cm occurred at the X and the Y axis, respectively. This means that the results fulfill the demanding accuracy of the 1:5000 digital map. Hence, it is possible to conclude from this study that the direct georeferencing based orthoimage generation method is able to effectively digital map update.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.310-310
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• 2019

본 연구에서는 기상청 ASOS(종관기상관측장비) 자료와 통계적 기반의 다중회귀분석모형을 이용하여 경안천 유역에 대한 봄철 강수량(3~5월 누적강수량)의 예측성을 평가하였다. 예측대상기간은 2006~2018년이며 예측인자로서 전국 96개 지점의 ASOS 자료 중 35개 기상요소에 대한 월 자료를 활용하였다. 전망기간(1~12개월)에 따라 강수량 기준 최소 1개월에서 최대 24개월까지의 지체시간을 고려하여 1~24개월 선행 ASOS 기상자료와 강수량 사이의 상관성을 분석하였다. 예측대상년도를 기준으로 과거 40년간의 자료를 이용하여 상관성 분석을 수행하였으며, 상관성이 높은 상위 30개 기상인자를 조합하여 다중회귀분석모형의 예측인자(독립변수)로 활용하였다. 예측대상년도와 전망기간에 따라 최적의 예측인자를 조합하고, 교차검증을 통하여 각각 4,000개의 다중회귀모형을 도출하여 예측범위를 산출하였다. 다중회귀모형에 의한 예측범위를 분석한 결과, 2013년 자료까지는 예측범위가 관측값을 잘 포함하고 예측값의 평균이나 중간값이 관측값과 유사하게 나타난 반면, 2014년부터는 전망기간에 따라 관측값과 예측범위의 차이가 크게 나타나는 경우도 있었다. 예측치의 중간값을 기준으로 3분위(평년 이상, 평년 수준, 평년 이하) 적중률을 분석하면, 2006~2013년에 대해서는 58.3%인 반면, 2014~2018년에 대해서는 11.2% 수준으로 나타났다.

• Journal of the Korean Society of Radiology
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• v.12 no.5
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• pp.651-658
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• 2018

A foot pedal switch in the diagnosis x-ray radiography system has been researched to improve radiologic technologist works and patient satisfaction. The switch has been installed in the diagnosis x-ray radiography system used in domestic clinics. Quantitative evaluation has been conducted by measuring the exposure dose reproducibility test, tube voltage, mAs, and percentage average error. Qualitative evaluation has been conducted by analysis of the radiologic technologists questionnaire. In the quantitative evaluation for the use of the foot pedal switch, the coefficient of variation was less than 0.05 in the exposure dose reproducibility test. In the mAs test, percentage average error of ${\pm}20%$ was measured. There was no problem raised since it meets the all inspection standards of the diagnosis x-ray generator. In the qualitative evaluation, most of the opinions are that it has a clinical value for the foot pedal switch in the diagnosis x-ray radiography system. Therefore, developing the foot pedal switch for the diagnosis x-ray radiography system can improve effectively the rapidity and accuracy of the radiologic technologist work. In addition, it is effective in decreasing the x-ray exposure of patients and increasing satisfaction for the medical service due to reduction of retaking x-ray.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.629-634
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• 2016

In this study, we investigated the effect of factors that influence the measurement of smoke density using synthetic rubber flooring. The characteristics of rolling stock in an enclosed environment can cause enormous loss of life by smoke inhalation during fires inside passenger cars. The amount of smoke generation from interior materials for rolling stock is strictly restricted domestically and in other countries. Precise measurement of smoke density is therefore required to assess the fire performance of interior materials. Major factors that influence the measurement of smoke density include the uniformity of the specimen, the variations in conditions and instruments, and the operational and maintenance environment of the instruments. The contribution of factors was analyzed by estimating the uncertainty to investigate the contribution ratios of the major factors. The results show a contribution ratio of about 86% for the variation from the measurement of light transmission using a photomultiplier tube. Thus, this factor was the most representative for the measurement of smoke density. The contribution ratio of the other factors was low at about 11%, including irradiant flux conditions (${\pm}0.5 kW/m^2$) and the influence of the operational and maintenance environment of the instrument. These results were obtained using specimens with high uniformity.