Currently, the development of evaluation technology for vibration and shock loads transmitted to spent nuclear fuel and structural integrity of spent nuclear fuel under normal conditions of transport is progressing in Korea by the present authors. Road transportation tests using surrogate spent nuclear fuel were performed in September, 2020 using a test model of KORAD-21 transportation cask and sea transportation tests were conducted from September 30 to October 4, 2021. In order to investigate amplification or attenuation characteristics, according to the load transfer path, a number of accelerometers were attached on a ship cargo hold, cradle, cask, canister, disk assembly, basket, and surrogate fuel assemblies and to investigate the durability of spent nuclear fuel rods, strain gages were attached on surrogate fuel assemblies. A ship named “JW STELLA” which has similar deadweight (5,000 ton) of existing spent nuclear fuel transportation ships was used for the sea transportation tests. The ship is propelled by 1,825 hp two main engines with two 4-bladed propellers. There are two major vibration sources in the ship. One is the vibration from waves and the other is the vibration from the engine and propeller system. The sensor locations on the ship were determined considering the vibration sources. The sea transportation test was performed for 5 days, the test data were measured successfully. The ship with the test model was departed from Changwon and sailed to Uljin, sailed west to Yeonggwang and then returned to Changwon. In addition to sailing on a designated test route, circulation test, braking/acceleration test, depth of water test, and rolling test were conducted. As a result of the preliminary data analysis of the sea test, power spectral densities and shock response spectrums were obtained according to the different test conditions. The vibratory loads caused by the wave mainly occurred in the frequency range of 0.1 to 0.3 Hz. The vibratory loads caused by the propeller occurred near the n/rev rotating frequencies, such as 5, 10, 20 Hz etc. However, those frequencies are far from the natural frequencies of local mode of the fuel rods, so it is considered that the vibratory loads from the wave and the propeller do not have a significant influence on the structural integrity of the fuel rods. Among all the test cases, maximum strain occurred at SG31 near the bottom nozzle on the test; the magnitude was 73.62 micro strain. Based on the analyzed road and sea transportation test data, a few input spectra for the shaker table test will be obtained and the shaker table test will be conducted in 2022. It is expected that the detailed vibration characteristics of the assembly which were difficult to identify from the test results can be investigated.

NFDC (Nuclear Fuel and materials Data Center) developed standard reference data for oxidation of HANA-6 cladding material. Thermo-gravimetric analyzer (TGA) was used to measure oxidation, and the measuring device was self-calibrated using standard materials. The oxidation amount of the HANA6 cladding was measured in an oxidizing atmosphere in the temperature range of 400 to 700°C. Through this, oxidation data, oxidation rate model equation, and graph were developed. The uncertainty factors were analyzed from the oxidation model. The expanded uncertainty of oxidation data was calculated by evaluating the uncertainty for each uncertainty factor. The oxidation data produced in this study was self-rated through deliberation by a specialized committee of NFDC and third experts. It was finally registered as a reference standard through the technical committee of the National Reference Standards Center. It is believed that the standard reference data developed in this study will be helpful for increasing reliability and stability evaluation of nuclear fuel and spent fuel.

In order to enhance the transparency of nuclear power, the investigation of nuclear activities is important at the right time. And investigation of North Korea, one of safety measures for such a surveillance system seems essential in the near future. However, the inspection period is limited and the possibility of revisiting is unclear, so it seems easy to install and more reliable monitoring devices are needed. The seal is a security device for monitoring forgery and alteration in the IAEA easily but simple. Since the existing seal devices used by IAEA and KINAC can only be checked through onsite inspections whether it is damaged or not, there is a limit to immediate response in the event of an emergency such as the theft of nuclear materials and loss of Continuity of Knowledge. While the North Korea-U.S. talks and inter-Korean talks are slowly approaching the North Korea’s nuclear issue, it is judged that the inspection of North Korea’s nuclear weapons is not in the distant future. Accordingly, it is necessary to develop a customized seal device for managing and monitoring spent nuclear fuel that can be used for inspection of North Korea. The real-time active seal device consists of a seal equipped with a detection sensor, a translator, and a server, and the translator use wireless communication in consideration of ease of installation and management, respectively. The translator and server use wired communication for data sustainability. The seal device is designed to maintain continuity of knowledge (COK) through wireless communication in consideration of security even in the event of equipment damage, malfunction, and loss of power, while enabling location detection in case of theft or abnormality. Therefore, in this study, a technical investigation on remote data communication was conducted accordingly, and a data communication module for a small amount of broadband data communication was manufactured and applied. In addition, several tests were conducted to determine data integrity and location accuracy according to the communication range.

Along with the current rapid development of technology, object classification is being researched, developed, and applied to security systems, autonomous driving, and other applications. A common technique is to use vision cameras to collect data of objects in the surrounding environment. Along with many other methods, LiDAR sensors are being used to collect data in space to detect and classify objects. By using the LiDAR sensors, some disadvantages of image sensors with the negative influence on the image quality by weather and light condition will be covered. In this study, a volumetric image descriptor in 3D shape is developed to handle 3D object data in the urban environment obtained from LiDAR sensors, and convert it into image data before using deep learning algorithms in the process of object classification. The study showed the potential possibility of the proposal and its further application.

The use of heat exchangers in various applications such as chemical, air conditioning systems, fuel processing, and power industries is increasing. In order to improve the performance of the heat exchanger, the problem of bonding quality of the copper tube, which is a major member, is emerging. However, since the copper tube is in the form of a pipe, it is difficult to identify internal defects with external factors. In this study, a thermal imaging camera was used to develop and verify an algorithm for detecting defects in the brazing part, and in the process, the brazing performance characteristics were analyzed according to the electrode position, and finally, a learning model was developed and performance evaluation was performed. It was confirmed that the method of supplying heat to the base material and melting the filler metal through the heat transfer effect is more effective than supplying heat input to the filler metal in the bonding process of copper tubes through high-frequency induction heating brazing. Thermal image data was used to develop a defect discrimination model, and 80% of training data and 20% of test data were selected, and a neural network-based single-layer copper tube brazing defect discrimination model was developed through k-Flod cross-validation., the prediction accuracy of 95.2% was confirmed as a result of the error matrix analysis.

이 연구는 전염병의 잠재적 확산 가능성이 높은 지역의 탐색을 목적으로, 코로나19 전후의 버스 네트워크 클러스터의 시공간적 변화를 분석한다. 분석방법으로는 Getis와 Ord의  통계를 공간 네트워크로 확장 및 적용한  통계 값을 사용하였다. 이 과정은 서울시 전체 버스 네트워크의 개별 흐름에 대해 각각 적용되기 때문에 대규모 연산을 위해 병렬컴퓨팅 방식을 적용한 슈퍼컴퓨터를 사용하였다. 연구 결과, 첫째, 코로나19 이후 버스 네트워크가 일부 흐름으로 집중된 경향을 보였다. 둘째, 코로나19이 후의 버스 흐름은 주거지, 농업지로의 이동은 증가하고 상업지역, 교통지역으로의 이동은 감소했음을 확인하였다. 셋째, 중심업무 지구 중 여의도 방면의 클러스터, 구로디지털단지역 방면의 클러스터와 달리, 강남일대는 코로나19 전후의 유의미한 변화가 나타나 지 않았다. 이 연구는 국내에서 처음으로 코로나19전후의 버스 네트워크 클러스터를 확인하고 변화 특징을 제시한다는 의미가 있다.

본 논문은 반도체, 디스플레이, 디지털 가전 및 휴대폰 등을 포괄하는 중국 전자산 업을 대상으로 OECD TiVA 데이터베이스를 활용하여 2000년~2018년까지의 중국 수 출을 부가가치 기준으로 분해하여 분석하였다. 분석 결과 중국 전자산업은 총 수출 액과 부가가치 수출액 모두 세계 1위로, 2018년 기준 중국 총수출의 약 30%를 차지 하고 있었다. 국내부가가치(DVA) 측면에서 중국은 해외 부품 조달을 통해 조립․가 공한 후 수출하는 비교적 저부가가치 활동을 담당하는 중간단계에 머무르고 있는 것 이 아니라 자국 부품 조달 및 국내 생산 비중을 높여 부가가치를 높인 것으로 분석 되었다. 주요국(한국, 대만, 미국, 일본)과의 비교에서 중국 전자산업의 국내부가가치 비중은 미국, 일본 다음으로 높은 비중을 차지하고 있었고 부가가치 기준 현시비교 우위지수(VRCA)도 높은 수준으로 상승하고 있었다.

Vegetation is the basis for biodiversity conservation and sustainable development. In the Environmental Impact Assessment (EIA), which is the most direct and efficient policy measure to prevent degradation of nature, vegetation-related assessment has limitations as it is not based on quantitative and scientific methods. In addition, it focuses on the presence of protected species; hence, it does not take into account the role of vegetation as a habitat on a wide-area scale. As a way to overcome these limitations, this study aims to contribute to the quantification and advancement of future EIA on vegetation. Through the review of previous studies, core areas, connectivity, and vegetation condition were derived as the items to be dealt within the macroscopic aspect of vegetation impact assessment. Each item was spatially constructed using land cover maps and satellite imageries, and time series change analysis was performed. As a result, it was found that vegetation has been continuously deteriorating due to development in all aspects, and in particular, development adversely affects not only the inside of the project site but also the surrounding area. Although this study suggested the direction for improvement of the EIA in the vegetation sector based on data analysis, a more specific methodology needs to be established in order to apply it to the actual EIA process. By actively utilizing various environmental spatial data, the impact of the development on the natural ecosystem can be minimized.

본 연구는 무분별한 섬 개발과 섬의 특성을 고려하지 않은 사업 등 섬 경관 특성 파악의 필요성이 증대됨과 동시에 기존 경관 연구의 한계를 보완하는 방법으로서 빅데이터 분석을 활용하고자 하였다. 따라서 본 연구는 섬 경관은 관광 동기의 중요 지표인 고유한 섬의 경관 특성을 파악함으로써 이를 고려한 계획 및 관리방안의 기초자료 제시를 목적으로 하였다. 연구의 범위는 가장 많은 섬을 보유하고 있는 전라남·북도의 섬 중 국내·외에서 인정받은 섬 중 빅데이터 분석을 하기에 용이한 데이터를 보유하고 있는 청산도, 선유도, 보길도, 박지·반월도로 한정하였다. 수집된 데이터는 사진 및 텍스트 데이터로서 이를 각각의 경관 특성을 파악하고 관계를 분석하기 위하여 형식미학적·심리적 경관특성으로 분류하여 결과를 도출하였다. 형식미학적 경관 특성은 사진 데이터를 토대로 경관파악모델 및 색채, 색채 이미지 형용사 분석을 실시하여 각 섬이 보유한 경관구성요소와 특성을 파악하였으며, 심리적 경관특성은 텍스트 데이터를 활용하여 빈도분석, N-gram, 네트워크 분석, 감성분석 등을 실시하여 경관 대상과 행태, 이미지 등을 파악하였다. 위와 같은 결과를 종합하여 섬 경관이 대중에게 어떻게 활용되고 있는지 의미를 파악하였으며 섬 연구에서 수행하는 데 발생되는 시간적·비용적 측면의 한계점뿐만 아니라 계절, 시계열 등 시간적 특성을 파악할 수 있다는 점에서 기존의 연구를 보완할 수 있었다. 또한, 각 섬의 경관 특성을 고려하여 추후 섬 발전 방향을 더욱 구체화시킬 수 있는 장치가 될 수 있다는 시사점을 제시하였다.