• Journal of Magnetics
• /
• 제21권4호
• /
• pp.516-523
• /
• 2016

In this paper, coupling factors are calculated based on numerical analysis in order to assess various non-uniform low-frequency magnetic field exposure situations. Two types of non-uniform magnetic field sources are considered; circular coil and parallel wires with balanced currents. For each magnetic field source, source current values are determined so that reference magnetic field magnitude can be measured at the specified point on the human model. Various exposure situations are investigated by changing parameters such as the distance between source and human model, radius of circular coil, and the gap between parallel wires. For equivalent human models, prolate spheroid model and simplified human model from IEC 62311 standard are used. The calculated coupling factor values are compared with those obtained by 2D uniform disk human model, and the dependence of coupling factor on the choice of equivalent human model is analyzed.

• 한국안전학회지
• /
• 제34권5호
• /
• pp.153-158
• /
• 2019

It is estimated that about 2,515 persons have been injured by conveyor for the past five years(2013 ~ 2017). Conveyors used in various industrial sites for transporting iron ore, coal, courier goods, etc., have various incidents such as a worker putting on or pulling a part of the body or work clothes on the driving part during maintenance. It is necessary for preventing similar accidents to conduct various researches. In order to propose the basis for revising laws and standards for the safety standards of the full cord switch to prevent conveyor accidents, this study compares Korea's Industrial Safety and Health Law (KISHL) with those of IEC, EN, Canada, and Australia. In addition, surveys of conveyor use plant and full cord switch domestic and foreign manufacturers was conducted. In this study, domestic and overseas related laws and technical standards compare and analyze to prevent conveyor accidents. In addition, we propose extension of safety certification for full code switch, establishment of safety inspection standard, and improvement of working method regulation through actual working condition investigation. It can be used as a basis for revising the occupational safety and health regulation and related notices, and thus contributing to enhancing the safe atmosphere of the conveyor business and improving the safety consciousness of the concerned persons.

• 정보보호학회논문지
• /
• 제29권5호
• /
• pp.985-996
• /
• 2019

본 논문에서는 미국에서 암호모듈검증을 획득한 대표적인 소프트웨어 형태의 암호모듈인 FIPS-OpenSSL의 소스 코드를 분석하여 암호모듈 검증 및 시험기준에서 요구하는 보안요구사항이 소프트웨어적으로 어떻게 구현되어있는지 분석한다. 특히, 암호모듈이 반드시 탑재하고 있어야 하는 자가시험기능 (동작 전 자가시험, 조건부 자가시험) 관점으로 소스코드를 분석한다. 비록 미국 암호모듈 검증제도에서는 FIPS 140-2를 검증기준으로 삼고 있지만, FIPS 140-2는 국내 암호모듈 검증제도에서 암호모듈 검증 및 시험기준으로 삼고 있는 암호모듈 국제표준인 ISO/IEC 19790과 24759의 근간이 되었기 때문에 많은 유사함이 존재한다. 본 논문의 분석을 통하여 향후 암호모듈 개발업체에서 자가시험기능을 정확하고 안전하게 구현할 수 있을 것으로 기대한다.

• International Journal of Internet, Broadcasting and Communication
• /
• 제13권3호
• /
• pp.169-177
• /
• 2021

Recently, the use of electric and electronic control systems is increasing in the automobile industry. This increase in the electric and electronic control system greatly increases the complexity of designing a vehicle, which leads to an increase in the malfunction of the system, and a safety problem due to the malfunction is becoming an issue. Based on IEC 61508 relating to the functional safety of electrical/electronic/programmable electronics, the ISO 26262 standard specific to the automotive sector was first established in 2011, and a revision was published in 2018. Malfunctions due to system failure are covered by ISO 26262, but ISO/PAS 21448 is proposed to deal with unintended malfunctions caused by changes in the surrounding environment. ISO 26262 sets out safety-related requirements for the entire life cycle. Functional safety analysis includes FTA (Fault Tree Analysis), FMEA (Failure Mode and Effect Analysis), and HAZOP (Hazard and Operability). These analysis have limitations in dealing with failures or errors caused by complex interrelationships because it is assumed that a failure or error affecting the risk occurs by a specific component. In order to overcome this limitation, it is necessary to apply the STPA (System Theoretic Process Analysis) technique.

• 한국기계가공학회지
• /
• 제20권7호
• /
• pp.48-57
• /
• 2021

The main research content of this paper is to evaluate the structural integrity and the cooling performance of 4250 kVA power transformer with ONAN(Oil Natural and Air Natural) mode. The dynamic analysis is used to verify the structural safety of the transformer by seismic loading. The transformer structure is simplified and NX software is used to build a three-dimensional model, and ANSYS commercial software is used to calculate the stress and deformation by applying corresponding load. The analysis result was evaluated whether it satisfies the design requirements according to the IEEE Std 693 standard. In terms of thermal analysis to evaluate the cooling performance, the thermal physical model is used to calculate the heat exchange between the radiator and the tank in the steady state, and the result is input into the Fluent software to calculate the internal temperature field of the transformer tank, which reduces the calculation cost of thermal fluid. Comparing the simulated hot spot temperature and top oil temperature of the transformer with the calculation results of the IEC60076 classic model, it is found that the error is only 1.9%.

• 드라이브 ㆍ 컨트롤
• /
• 제20권1호
• /
• pp.34-40
• /
• 2023

The agricultural tractor ROPS test method according to OECD code 4 is a test to assess whether the driver's safety area can be secured when a tractor overturns, and reliability should be ensured. In this study, a model formula and procedure for calculating measurement uncertainty expressing reliability in the field of agricultural machinery testing were established according to the ISO/IEC Guide 98-3:2008. The characteristics of the ROPS test device were assessed and repeated tests were performed, and the were used as factors to calculate the measurement uncertainty. As a result of repeated tests, the accuracy was higher than 1.9 % in all load directions; thus, they were, applied to calculate the type A standard uncertainty. The final expanded uncertainty was calculated within the range of less than ± 7.76 kN of force and ± 6.96 mm of deformation in all load directions.

• 한국인공지능학회지
• /
• 제11권3호
• /
• pp.1-5
• /
• 2023

With recent advancements in artificial intelligence (AI) technology, more products based on AI are being launched and used. However, using AI safely requires an awareness of the potential risks it can pose. These concerns must be evaluated by experts and users must be informed of the results. In response to this need, many countries have implemented certification programs for products based on AI. In this study, we analyze several trends and differences in AI product certification programs across several countries and emphasize the importance of such programs in ensuring the safety and trustworthiness of products that include AI. To this end, we examine four international AI product certification programs and suggest methods for improving and promoting these programs. The certification programs target AI products produced for specific purposes such as autonomous intelligence systems and facial recognition technology, or extend a conventional software quality certification based on the ISO/IEC 25000 standard. The results of our analysis show that companies aim to strategically differentiate their products in the market by ensuring the quality and trustworthiness of AI technologies. Additionally, we propose methods to improve and promote the certification programs based on the results. These findings provide new knowledge and insights that contribute to the development of AI-based product certification programs.

• 풍력에너지저널
• /
• 제14권1호
• /
• pp.14-20
• /
• 2023

In this study, using the commercial software Bladed developed by DNV for integrated load calculation of wind turbines, the generation of seismic waves according to soil type based on Korea's domestic regulations, and load calculation considering earthquake conditions were performed according to the IEC standard, and load in the main coordinate system of the fixed offshore wind turbine was calculated. By comparing the calculated load with the design load of the fixed offshore wind turbine, the effect of earthquake loads according to soil type on the main components of fixed offshore wind turbines was evaluated. As a result of the evaluation, when an earthquake load on a wind turbine is considered, the effect of the earthquake load is related to the natural frequency of the major components and the magnitude of the adjacent acceleration in the earthquake response spectrum, and the earthquake load differs according to soil type and may exceed the design load.

• 핵의학기술
• /
• 제16권2호
• /
• pp.29-34
• /
• 2012

Siemens사의 CT 선량 감소 소프트웨어인 IRIS의 적용을 통하여 CT 선량 감소 시 노이즈 감소 효과와 해상력의 보존 그리고 ACCT에 IRIS 각 kernel의 적용 시 SUV 변화를 확인하는데 목적을 두었다. Biograph mCT 40 slice 스캐너를 이용하여 AAPM CT performance phantom, Anthropomorphic chest phantom을 관전압 120 kVp로 고정하고 100-10 mAs까지 15%감소하여 스캔 후 FBP, IRIS 각 kernel을 적용하여 재구성 하여 영상의 노이즈, 해상력, 영상 평가를 시행하였다. NEMA IEC body phantom을 이용하여 55.5 MBq를 background에 주입하고 열소와 배후 방사의 비를 8:1이 되도록 모형을 제작하였다. 120 kVp, 50 mAs 조건으로 1분, 2분, 3분, 4분 스캔하여 영상을 획득한 후 ACCT에 IRIS 각 kernel을 적용하여 기존 FBP 방식을 적용한 SUV와의 평가를 시행하였다. IRIS의 적용 시 기존 FBP 방식에 비하여 45% 선량을 감소하였음에도 불구하고 해상력 저하 없는 노이즈 감소 효과가 확인 되었으며 SUV 평가 실험에서 IRIS의 I70f kernel을 제외하고는 기존 FBP 방식을 통하여 획득된 SUV와 유의한 차이가 나타나지 않았다. 본 연구를 통하여 IRIS 적용 시 기존 FBP 방식에 비하여 CT 피폭선량 감소와 해상력 저하 없는 노이즈 감소 효과를 입증하였으며 IRIS kernel의 적절한 적용을 통하여 PET/CT 검사 시 환자 피폭선량 감소는 물론 FBP 방식에 비하여 우수한 영상의 획득이 가능할 것이라 사료된다.

• 핵의학기술
• /
• 제14권1호
• /
• pp.54-60
• /
• 2010

본원에 도입된 새로운 소프트웨어는 SPECT나 전신 뼈 영상에만 국한되어 사용되어 지고 있지만 보다 효과적으로 다른 검사에 적용하기 위해 팬텀을 통한 실험과 영상의 비교를 통하여 그 유용성을 찾아보고자 하였다. 실험을 위하여 Body IEC phantom과 Jaszczak ECT phantom, Capillary를 이용한 실린더 팬텀을 이용하였고, 영상의 처리 전후의 계수, statistics를 비교해 보고 contrast ratio나 BKG의 변화들을 정량적으로 분석해 보았다. Capillary source를 이용한 FWHM 비교에서는 PIXON의 경우 처리 전후의 영상에서 차이가 거의 없었고, ASTONISH의 경우 처리 후의 영상이 우수해짐을 확인할 수 있었다. 반면 Standard deviation과 그에 따른 Variance는 PIXON은 다소 감소한 반면 ASTONISH는 큰 폭으로 증가함을 보였다. IEC phantom을 이용한 BKG variability 비교에서는 PIXON의 경우 전체적으로 감소한 반면 ASTONISH는 다소 증가하는 경향을 보였고, 각각의 sphere에 대한 contrast ratio도 두 가지 방법 모두 향상됨을 확인하였다. 영상의 스케일 면에서도 PIXON의 경우 처리 후에는 window width가 약 4-5배 증가하였지만 ASTONISH에서는 큰 차이가 없었다. 팬텀 실험 분석 후 ASTONISH는 정량적 분석을 위해 ROI를 그려야 하는 기타 검사와 대조도를 강조하는 검사에 적용 가능성을 보였고, PIXON은 획득계수가 부족하거나 SNR이 낮은 핵의학 검사에 유용하게 사용될 것으로 생각되었다. 영상의 분석 인자로 많이 사용되는 정량적인 수치들은 소프트웨어의 적용 후 대체로 향상되었지만 감마카메라의 차이보다 소프트웨어간의 알고리즘 특성으로 인한 결과영상의 차이가 많아 모든 핵의학 검사의 적용에 있어서 일관성을 유지하기는 어려울 것으로 사료된다. 또한 전신 뼈 영상과 같이 검사시간의 획기적 단축과 같은 수단으로는 우수한 영상의 질을 기대하기 어렵다. 새로운 소프트웨어의 도입 시 병원의 특성에 맞는 protocol과 임상 적용 전에 많은 연구가 필요할 것으로 사료된다.