• 한국생산제조학회지
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• 제25권6호
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• pp.486-491
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• 2016

Disturbance/vibration reduction is critical in many applications using machine vision. The off-focusing or blurring error caused by vibration degrades the machine performance. In line with this, real-time disturbance estimation and avoidance are proposed in this study instead of going with a more familiar approach, such as the vibration absorber. The instantaneous motion caused by the disturbance is sensed by an attitude heading reference system module. A periodic vibration modeling is conducted to provide a better performance. The algorithm for vibration avoidance is described according to the vibration modeling. The vibration occurrence function is also proposed, and its parameters are determined using the genetic algorithm. The proposed algorithm is experimentally tested for its effectiveness in the vision inspection system.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.237-240
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• 2006

Almost 30 years have been passed since the first nuclear power plant was operated in Korea. Many studies have been actively conducted from the early 1990's in order to develop the deterioration management system for concrete structures in NPPs(Nuclear Power Plants) accordingly. Base on these studies, a systematic deterioration management program has developed and operated since 1997. According to this program, systematic inspections to provide database and evaluation were periodically performed (every overhaul at intervals of $12{\sim}18$ month and every five years). Accumulated deterioration database was usefully utilized for the NPP PSR (Periodic Safety Review). In this paper, the long-term durability and integrity of Kori 1,2 NPP concrete structures which are the oldest ones in Korea were evaluated based on the precise inspection database and regulatory inspection results including compressive strength, depth of carbonation, amount of chlorination and spontaneous potential of reinforcing bar, etc. It was noted that Kori 1,2 NPP structures have not any serious durability problems.

• 정보보호학회논문지
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• 제32권1호
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• pp.109-122
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• 2022

정보보안 활동의 목적은 해킹 등으로 인한 피해가 발생한 이후 그 원인을 찾아 후속 조치하는 것 뿐만 아니라 주기적인 보안 활동을 통해 제어시스템 등 중요 시스템의 해킹 피해 시 우려되는 대규모 물적·인적사고를 줄이는 데에 있다. 이에 각 기관에서는 관련 규정에 따른 보안감사모델을 활용하고 있지만 시간과 인력의 제약으로 인해 전사적 점검활동을 수행하는 것이 쉽지 않다. 본 논문에서는 최근 10년간 공공기관의 주요 취약점에 대해 분석해보고 국내외 보안감사를 위한 모델과 비교하여 효율적인 보안활동을 수행할 수 있는 보안감사모델을 제시하고자 한다.

• Asian Pacific Journal of Cancer Prevention
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• 제17권9호
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• pp.4313-4318
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• 2016

Background: This study documented the performance of providers of visual inspection with acetic acid (VIA) at primary health centers, assessing their compliance with the VIA skills checklist and determinants of non-compliance, and exploring their perceptions of VIA training sessions. Materials and Methods: A cross-sectional study was conducted among VIA providers in the $Mekn\grave{e}s$-Tafilalet region of Morocco. Structured observation of their performance was conducted through supervisory visits and multiple focus group discussions (FGDs). Results: Performance of all the recommended steps for effective communication was observed in a low proportion of procedures (36.4%). Midwives/nurses had higher compliance than general practitioners (GPs) (p<0.001). All recommended steps for VIA examination were performed for a high proportion of procedures (82.5%). Compliance was higher among midwives/nurses than among GPs (p<0.001) and among providers in rural areas than those in urban areas (p<0.001). For pre-VIA counselling, all recommended steps were performed for only 36.8% of procedures. For post-VIA counseling, all recommended steps were performed in a high proportion (85.5% for VIA-negative and 85.1% for VIA-positive women). Midwives/nurses had higher compliance than GPs when advising VIA-positive women (p=0.009). All infection prevention practices were followed for only 14.2% of procedures, and compliance was higher among providers in rural areas than those in urban areas (p<0.001). Most FGD participants were satisfied with the content of VIA training sessions. However, they suggested periodic refresher training and supportive supervision. Conclusions: Quality assurance of a cervical cancer screening program is a key element to ensure that the providers perform VIA correctly and confidently.

• Structural Engineering and Mechanics
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• 제31권5호
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• pp.507-526
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• 2009

Based on numerical and experimental methods, a systematic structural evaluation of a steel natatorium in service was carried out in detail in this paper. Planning of inspection tasks was proposed firstly according to some national codes in China in order to obtain the economic and reliable results. The field visual inspections and static computation were conducted in turn under in-service environmental conditions. Further a three-dimensional finite element model was developed according to its factual geometry properties obtained from the field inspection. An analytical modal analysis was performed to provide the analytical modal properties. The field vibration tests on the natatorium were conducted and then two different system identification methods were used to obtain the dynamic characteristics of the natatorium. A good correlation was achieved in results obtained from the two system identification methods and the finite element method (FEM). The numerical and experimental results demonstrated that the main structure of the natatorium in its present status is safe and it still satisfies the demand of the national codes in China. But the roof system such as purlines and skeletons must be removed and rebuilt completely. Moreover the system identification results showed that field vibration test is sufficient to identify the reliable dynamic properties of the natatorium. The constructive suggestion on structural evaluation of the natatorium is that periodic assessment work must be maintained to ensure the natatorium's safety in the future.

• International Journal of Naval Architecture and Ocean Engineering
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• 제10권2호
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• pp.153-169
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• 2018

A submarine has a pressure hull that can withstand high hydraulic pressure and therefore, requires the use of highly advanced shipbuilding technology. When producing a pressure hull, periodic inspection, repair, and maintenance are conducted to maintain its soundness. Of the maintenance methods, Non-Destructive Testing (NDT) is the most effective, because it does not damage the target but sustains its original form and function while inspecting internal and external defects. The NDT process to detect defects in the welded parts of the submarine is applied through Magnetic particle Testing (MT) to detect surface defects and Ultrasonic Testing (UT) and Radiography Testing (RT) to detect internal defects. In comparison with RT, UT encounters difficulties in distinguishing the types of defects, can yield different results depending on the skills of the inspector, and stores no inspection record. At the same time, the use of RT gives rise to issues related to worker safety due to radiation exposure. RT is also difficult to apply from the perspectives of the manufacturing of the submarine and economic feasibility. Therefore, in this study, the Phased Array Ultrasonic Testing (PAUT) method was applied to propose an inspection method that can address the above disadvantages by designing a probe to enhance the precision of detection of hull defects and the reliability of calculations of defect size.

• 대한토목학회논문집
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• 제43권2호
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• pp.165-173
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• 2023

교량에 발생하는 손상에 대한 관리 및 평가는 정기적인 점검으로 작성된 보고서와 외관조사망도 및 손상물량표를 포함한 점검 및 진단자료에 기초한다. 이러한 자료 대부분은 2D 기반의 문서형식으로 작성되어 있고, 표준화된 방식으로 디지털화하기 어려워 정해진 목적 외의 활용이 쉽지 않다. 이에 본 연구에서는 점검자료를 기반으로 손상을 포함한 BIM 기반 교량모델을 구축하는 방법을 제시하고, BIM 표준을 준용하는 유지관리용 건설정보교환표준인 COBie (Construction Operations Building Information Exchange)를 사용하여 모델로부터 도출한 스프레드시트 데이터 형식의 손상정보들을 교량모델과 연계하여 관리하고 활용하는 방법을 제시하였다. 또한 전술한 방법들을 이용해 손상이 발생한 교량 상부구조 각 부위별 상태등급을 디지털 데이터 기반으로 자동화된 방법으로 평가하는 방법을 제안하였다. 본 연구에서 제안된 방법들은 PSC I형 콘크리트 교량의 상부구조를 대상으로 검증이 이루어졌으며 그 실효성이 검증되었다.

• 자동차안전학회지
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• 제14권1호
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• pp.26-31
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• 2022

Changwon City has the second highest accident rate with 79.6 according to the city bus accident rate. In fact, 250,000 people use the city bus a day in Changwon, The number of accidents is increasing gradually. In addition, a recent fire accident occurred in the engine room of a city bus (CNG) in Changwon, which has gradually expanded the public's anxiety. In the case of business vehicles, the government conducts inspections with a short inspection cycle for the purpose of periodic safety inspections, etc., but it is not in the monitoring stage. In the case of city buses, the operation records are monitored using Digital Tacho Graph (DTG). As such, driving records, methods, etc. are continuously monitored, but inspections are conducted every six months to ascertain the safety and performance of automobiles. It is difficult to identify real-time information on automobile safety. Therefore, in this study, individual automobile management solutions are presented through machine learning techniques of inspection results based on driving records or habits by linking DTG data and Vehicle Inspection Management System (VIMS) data for city buses in Changwon from 2019 to 2020.

• Nuclear Engineering and Technology
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• 제55권4호
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• pp.1485-1494
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• 2023

The bow of the nuclear fuel assembly is a well-known phenomenon. One of the vital criteria during the history of nuclear fuel development has been fuel assembly's mechanical stability. Once present, the fuel assembly bow can lead to safety issues like excessive water gap and power redistribution or even incomplete rod insertion (IRI). The extensive bow can result in assembly handling and loading problems. This is why the fuel assembly's bow is one of the most often controlled geometrical factors during periodic fuel inspections for VVER when compared e.g. to on-site fuel rod gap measurements or other instrumental measurements performed on-site. Our proposed screening method uses existing video records for fuel inspection. We establish video frames normalization and aggregation for the purposes of bow measurement. The whole process is done by digital image processing algorithms which analyze rotations of video frames, extract angles whose source is the fuel set torsion, and reconstruct torsion schema. This approach provides results comparable to the commonly utilized method. We tested this new approach in real operation on 19 fuel assemblies with different campaign numbers and designs, where the average deviation from other methods was less than 2 % on average. Due to the fact, that the method has not yet been validated during full scale measurements of the fuel inspection, the preliminary results stand for that we recommend this method as a complementary part of standard bow measurement procedures to increase measurement robustness, lower time consumption and preserve or increase accuracy. After completed validation it is expected that the proposed method allows standalone fuel assembly bow measurements.

• 대한교통학회지
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• 제25권3호
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• pp.65-74
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• 2007

1995년 이후 연평균 6.2%의 증가율을 보이는 자동차 등록대수에 반해 연평균 교통사고 발생건수는 1.5%, 사망자 4.7% 및 부상자 0.3%씩 감소추세를 보이고 있어 매우 다행스러운 일이나, OECD국가와 비교해서는 여전히 높은 교통사고율을 보이는 것이 사실이다. 이에 정부 및 각 기관에서는 교통사고를 감소시키기 위해 지속적인 교통안전사업을 추진하고 있으나, 각 제도 및 사업에 대한 시행 효과를 측정하는 부분에 대해서는 소홀히 하고 있는 현실이다. 정부가 교통안전을 위한 사업의 일환으로 시행중인 자동차검사제도는 차량의 도로운행 적합성 확인을 통해 자동차의 안전도 확보 및 교통사고로 인한 국민의 생명과 재산을 보호하는 것을 목적으로 하고 있다. 하지만. 이 제도에 대한 효과분석이 제대로 이루어지지 않은 상황이고, 자동차검사제도와 무관하게 운전자 스스로 자동차의 안전관리 상태를 수시 점검한다는 의견 등 자동차 검사방법, 검사기준, 검사의 실효성 저하에 대한 논의가 지속적으로 제기되고 있는 실정이다. 이에 본 연구에서는 자동차검사제도가 구조장치의 안전성을 향상시키고. 자동차성능을 유지시킴으로써 자동차결함으로 인해 발생 가능한 교통사고의 사전예방에 어느 정도 기여하는지 정량적으로 보임으로써 자동차검사제도의 효과를 측정 해 보고자 하였다. 2005년도 자료를 기준으로 교통사고 감소건수를 추정해 본 결과 자동차검사제도 시행을 통한 교통사고 감소건수는 약 23,735건으로, 이는 2005년 총 교통사고 건수 214,171의 11%에 달하는 것으로 나타났다.