Water utilities are making various efforts to reduce water losses from water networks, and an essential part of them is to recognize the moment when a pipe burst occurs during operation quickly. Several physics-based methods and data-driven analysis are applied using real-time flow and pressure data measured through a SCADA system or smart meters, and methodologies based on machining learning are currently widely studied. Water utilities should apply various approaches together to increase pipe burst detection. The most intuitive and explainable water balance method and its procedure were presented in this study, and the applicability and detection performance were evaluated by applying this approach to water supply pipelines. Based on these results, water utilities can establish a mass balance-based pipe burst detection system, give a guideline for installing new flow meters, and set the detection parameters with expected performance. The performance of the water balance analysis method is affected by the water network operation conditions, the characteristics of the installed flow meter, and event data, so there is a limit to the general use of the results in all sites. Therefore, water utilities should accumulate experience by applying the water balance method in more fields.

Particulate matter is known to have adverse effects on health, making it crucial to accurately gauge its concentration levels. While the recent advent of low-cost air sensors has enabled real-time measurement of particulate matter, discrepancies in concentrations can arise depending on the sensor used, the measuring environment, and the manufacturer. In light of this, we aimed to propose a method to calibrate measurements between low-cost air sensor devices. In our study, we introduced decision tree techniques, commonly used in machine learning for classification and regression problems, to categorize particulate matter concentration intervals. For each interval, both univariate and multivariate multiple linear regression analyses were conducted to derive calibration equations. The concentrations of PM10 and PM2.5 measured indoors and outdoors with two types of LCS equipment and the GRIMM 11-A device were compared and analyzed, confirming the necessity for distinguishing between indoor and outdoor spaces and categorizing concentration intervals. Furthermore, the decision tree calibration method showed greater accuracy than traditional methods. On the other hand, during univariate regression analysis, the proportion exceeding a PM2.5/PM10 ratio of 1 was significantly high. However, using multivariate regression analysis, the exceedance rate decreased to 79.1% for IAQ-C7 and 89.3% for PMM-130, demonstrating that calibration through multivariate regression analysis considering both PM10 and PM2.5 is more effective. The results of this study are expected to contribute to the accurate calibration of particulate matter measurements and have showcased the potential for scientifically and rationally calibrating data using machine learning.

The development of advanced nuclear facilities is progressing rapidly around the world. Newly designed facilities have differences in structure and operation from existing nuclear facilities, so Safeguards by Design (SBD), which applies safeguards at the design stage, is important. To this end, designers should consider the safeguardability of nuclear facilities when designing the system. Safeguardability represents a measure of the ease of safeguards, and representative evaluation methodologies are Facility Safeguardability Analysis (FSA) and Safeguardability Check-List (SCL). Those two have limitations in the quantification of safeguardability. Accordingly, in this study, the Safeguardability Evaluation Method (SEM), which has clear evaluation criteria based on engineering formulas, was developed. Nuclear Material Accountancy (NMA), a key element of Safeguards, requires the Material Balance Area (MBA) of the target facility and performs Material Balance Evaluation (MBE) based on the quantitative evaluation of nuclear materials entering or leaving the MBA. In this study, about 10 factors related to NMA were developed, including MBA, Key Measurement Point (KMP), Uncertainty of a detector, Radiation signatures, and MUF (Material Unaccounted For). For example, one of the factors, MUF is used in MBA to determine diversion through analysis of unquantified nuclear materials and refers to the difference between Book Inventory and Physical Inventory, as well as errors occurring during the process in bulk facilities, errors in measurement, or intentional use of nuclear materials. This occurs in situations such as attempted diversion, and accurate MUF evaluation is essential for solid Safeguards implementation. MUF can be evaluated using the following formula (MUF=(PB+X-Y)-PE). The IAEA’s Safeguards achievement conditions (MUF < SQ) should be met. Considering this, MUF-related factors were developed as follows. (􀜵􀜧􀜯 = 1 − 􀯆􀯎􀮿 􀯌􀯊 ) In this way, about 10 factors were developed and described in the text. This factors is expected to serve as an important factor in evaluating the safeguardability of NMA, and in the future, safeguardability factors related to Containment & Surveillance (C&S) and Design Information Verification (DIV) will be additionally developed to conduct a comprehensive safeguardability evaluation of the target facility. This methodology can significantly enhance safeguardability during the design stage of nuclear facilities.

The Republic of Korea (ROK), as a member state of the IAEA, is operating the State’s System of Accounting for and Control (SSAC) and conducting independent national inspections. Furthermore, an evaluation methodology for the material unaccounted for (MUF) is being developed in ROK to enhance capabilities of national inspection. Generally, physical and chemical changes of nuclear material are unavoidable due to the operating system and structure of facilities, an accumulation of material unaccounted for (MUF) has been issued. IAEA developed statistical MUF evaluation method that can be applied to all facilities around the world and it mainly focuses on the diversion detection of nuclear materials in facilities. However, in terms of the national safeguard inspection, an evaluation of accountancy in facilities is additionally needed. Therefore, in this research, a new approach to MUF evaluation is suggested, based on the Guide to the Expression of Uncertainty in Measurement (GUM) that an evaluation of measurement uncertainty factors is straightforward. A hypothetical list of inventory items (LII) which has 6,118 items at the beginning and end of the material balance period, along with 360 inflow and outflow nuclear material items at a virtual fuel fabrication plant was employed for both the conventional IAEA MUF evaluation method and the proposed GUM-based method. To calculate the measurement uncertainty, it was assumed that an electronic balance, gravimetry, and a thermal ionization mass spectrometer were used for a measurement of the mass, concentration, and enrichment of 235U, respectively. Additionally, it was considered that independent and correlated uncertainty factors were defined as random factors and systematic factors for the ease of uncertainty propagation by the GUM. The total MUF uncertainties of IAEA (σMUF) and GUM (uMUF) method were 37.951 and 36.692 kg, respectively, under the aforementioned assumptions. The difference is low, it was demonstrated that the GUM method is applicable to the MUF evaluation. The IAEA method demonstrated its applicability to all nuclear facilities, but its calculated errors exhibited low traceability due to its simplification. In contrast, the calculated uncertainty based on the GUM method exhibited high reliability and traceability, as it allows for individual management of measurement uncertainty based on the facility’s accounting information. Consequently, the application of the GUM approach could offer more benefits than the conventional IAEA method in cases of national safeguard inspections where factor analysis is required for MUF assessment.

PURPOSES : The increase in particulate matter due to increased air pollutant emissions has become a significant social issue. According to the Ministry of Environment, air pollutants emitted from large-scale businesses in 2022 increased by 12.2% compared to the previous year, indicating that air pollution is accelerating owing to excessive industrialization. In this study, TiO2, which is used to reduce airborne particulate, was used. The TiO2 coating fixation and dynamic pressure coating-type TiO2 fixation methods were used to solve the material peeling phenomenon caused by gravity, which is a limitation when the TiO2 penetration method is applied to a vertical concrete structure along the road. The long-term durability and performance were analyzed through environmental resistance and NOx removal efficiency evaluation experiments. These analyses were then assessed by comparing the NOx removal efficiency with the dynamic pressure permeationtype TiO2 fixation method used in previous studies. METHODS : To evaluate the long-term durability and performance of the TiO2 coating fixation method and dynamic pressure coating TiO2 fixation method for vertical concrete structures, specimens were manufactured based on roadside vertical concrete structures. Environmental resistance tests such as the surface peeling resistance test (ASTM C 672) and freeze-thaw resistance test (KS F 2456) were conducted to evaluate the long-term durability. To evaluate the long-term performance, the NOx removal efficiency of TiO2 concrete owing to road surface deterioration during the environmental resistance test was evaluated using the NOx removal efficiency evaluation equipment based on the ISO 22197-1 standard. This evaluation was compared and analyzed using the dynamic pressure infiltration TiO2 fixation method. RESULTS : The long-term durability of the TiO2 coating fixation and dynamic pressure coating TiO2 fixation methods were evaluated using environmental resistance tests. During the surface peeling resistance test, the TiO2 material degraded and partially detached from the concrete. However, the NOx removal efficiency was ensured by the non-deteriorated and fixed TiO2 material. The long-term performance was confirmed through a freeze-thaw resistance test to evaluate the NOx removal efficiency after 300 cycles of surface deterioration. The results showed that when the TiO2 coating fixation and dynamic pressure infiltration TiO2 fixation methods were applied to vertical concrete structures, the durability of the structure was not compromised. In comparison to the dynamic pressure infiltration TiO2 fixation method, the NOx removal efficiency observed during the surface peeling resistance test was lower, while the freeze-thaw test exhibited notably higher removal efficiency. CONCLUSIONS : To solve the material peeling phenomenon caused by gravity, the long-term durability and performance were evaluated by applying the TiO2 coating fixation and dynamic pressurized coating TiO2 fixation methods to vertical concrete specimens. Long-term durability was confirmed through environmental resistance tests, and long-term utility was secured by measuring the NOx removal efficiency according to surface degradation. These findings show that implementing the TiO2 coating fixation method and dynamic pressure coating TiO2 fixation methods on-site effectively reduce NOx.

한 척의 선박을 건조하기 위해서는 다양한 크기의 블록(block)들을 이동 및 탑재해야 한다. 이러한 과정에서 블록의 체결 방법 및 각 조선소 설비 특성에 맞는 다양한 기능에 부합하는 러그를 사용하고 있다. 블록 구조의 중량 및 형태에 따라서 러그의 크기와 형상이 다양하며, 샤클(shackle)이 체결되는 홀 주변에 부족한 강성을 보완하기 위하여 덧판(doubling pad)을 용접하여 구조를 보강한다. 리프팅 (lifting) 조건별 러그의 설계를 하는 방법은 보 이론(beam theory)에 의한 수계산 방법과 유한요소해석 모델링을 이용한 구조해석을 수행하고 있다. 해석적 방법의 경우, 요소의 종류와 모델링 방법에 따라서 결과 차이가 발생하여 표준화된 평가법의 정립이 필요한 상황이다. 이러한 모호한 방법론 적용 시 블록의 이동 및 반전(turn-over) 과정 중에서 심각한 안전 문제를 유발할 가능성이 있다. 본 연구에서는 러그의 실제 탑재공정에 따른 구조 응답을 평가할 수 있는 모델링 조건, 평가법을 확정하고자 다양한 변수의 영향을 수치 구조해석을 통하여 비교 및 분석하였다. 러그 홀(hole) 주변 덧판부와 용접 비드(bead)를 표현한 모델링 기법이 가장 실제적인 거동 결과를 주고 있다. 실제 러그와 동일 한 조건(용접부 비드만 주재료와 연결)의 모델링에 등가하중을 적용한 결과는 MPC 하중 적용 결과보다 낮은 최종강도를 나타낸다. 더불어 해석 시간 단축을 위해서 2차원 쉘(shell) 요소를 적용한 경우, 덧판 두께를 85% 수준으로 감소시켜서 안전사용하중을 예측할 수 있음을 확 인하였다. 논문에서 검토한 다양한 변수의 영향들 결과는 러그 설계 및 안전사용하중 예측에 근거 자료로 활용될 것으로 기대된다.

본 연구는 부도덕한 행동 이후에 발생하는 정화행동에 대한 도덕적 평가가 행위자의 자원 가용성에 따라 달라지는지를 검증했다. 이를 위해 행위자 특성(사회경제적 수준, 신체건강 수준)을 달리하여 도덕적 정화방법(기부, 봉사)에 따른 자원 가용성을 조작했으며, 참가자들은 도덕적 정화행동에 따른 고통, 위선의 정도, 그리고 용서 가능성을 평정했다. 연구 1에서는 사회경제적 수준이 높거나 낮은 사람이 기부 혹은 봉사를 통해 도덕적 정화행동을 하는 시나리오를 제시했다. 그 결과 참가자들은 부유한 사람의 기부는 고통스럽지 않았을 것이며, 위선적이고 용서하기 어렵다고 판단했다. 연구 2에서는 신체가 건강하거나 병약한 사람이 기부 혹은 봉사를 통해 잘못을 정화하는 내용을 제시했다. 그 결과 병약한 사람의 봉사활동은 고통스러웠을 것이며, 덜 위선적이며 (다른 조건에 비해) 용서 가능성을 높게 평가했다. 매개분석 결과 연구 1, 2 모두에서 정화행동의 고통이 클수록 위선을 약하게 판단하며, 이는 용서 가능성을 높이는 매개효과가 나타났다. 이 결과들은 동일한 정화행위라도 행위자의 자원 가용성에 따라 도덕적 판단이 달라짐을 보여준다. 즉, 사람들은 도덕적 정화행동은 고통을 수반해야 하며 그렇지 않은 경우 그 행위는 위선적이며 용서하기 어렵다고 평가함을 알수 있다.

Integrity evaluation scheme for Spent Fuel (SF) dry storage has been developed under transportation failure modes. This method especially considered the degradation characteristics of Spent Fuel (SF) during dry storage such as radial and circumferential hydride content, hydride volume fraction, oxide thickness, etc. Hydride and zircaloy cladding are considered as material composite system, using correlation models related to material properties. Critical Strain Energy Density (CSED) is compared with Strain Energy Density (SED), to evaluate cladding integrity. CSED serves as material characteristics, while SED can be considered as boundary condition. To calculate the CSED of cladding in the lateral failure mode, circumferential hydride concentration is used. SED is calculated considering both the bending moment and axial load. On the other hand, in the longitudinal failure case, fuel rod temperature, internal pressure, hoop stress, radial hydride concentration is used to calculate CSED. And pinch force (contact) was considered to evaluate SED. Model validations were conducted by comparing hot cell SF test and existing validated evaluation results. To separately handle normal transportation conditions from hypothetical accident conditions, SED according to stress-strain analysis results was separated into elastic and plastic regions. As a result of applying this scheme for 14×14 SF, failure probability of normal condition was zero, which is the similar result with DOE and same with EPRI. Regarding accident condition, lateral case showed similar result, but longitudinal case showed different but reasonable result, which was due to the different analysis conditions. The proposed methodology which was indigenously developed through this study is named as K-method.

This study sought to conduct a fundamental investigation in order to test and evaluate the thermal performance of an aluminum stick curtain wall system. In terms of the thermal performance index, the infiltration rate of air tightness, thermal transmittance of the heat insulation property and temperature difference ratio of condensation resistance were experimentally measured. The research process can be divided into three parts. First of all, a database for the test report of the curtain wall was compiled and existing design criteria with respect to the evaluation method and standard of transparent building components such as curtain wall, window and door were analyzed to produce the specimens. Secondly, four different types of curtain wall specimens were created through investigating the curtain wall database. Thirdly, standard tests of thermal performance were carried out for airtightness, thermal performance and condensation resistance. As a result, the curtain wall specimens with low-e triple glazing covered by an aluminum capture system showed high thermal performance compared to other curtain wall specimens including low-e triple glazing with a 4-sided structural sealant glazing system. Air tightness of all types of curtain wall specimens satisfied level 1 standard for air tightness. It was found that a curtain wall which consists of a one track frame has difficulties meeting the residential standard of thermal performance with regard to thermal transmittance and condensation resistance.

우리나라는 삼면이 바다이며 북쪽과 동쪽으로 산지가 위치하고 서쪽으로는 평탄한 지리적 특성을 가진다. 또한 계절풍, 태풍 등의 바람이 지리적 특성으로 인하여 지역마다 풍향별 풍속이 다르다. 그러나 건축구조기준(이하 KDS 41 12 00: 2019)은 전풍향에 대 해 동일한 풍속을 적용한다고 규정하였고, 이것은 상대적으로 약한 풍향에 대해 과다한 풍속을 적용할 수 있다. 이런 점을 고려하여 건 축구조기준(이하 KDS 41 12 00: 2022)에서는 합리적인 설계를 위해 풍향계수를 적용한다. 본 연구는 8개소를 대상으로 10년간의 자 료를 수집하여 사용성 평가를 위한 1년 재현기대풍속과 풍향계수를 산출하였다. 선행 연구된 논문에서 사용성 평가를 위한 1년 재현 기대풍속과 풍향계수를 산출하였으나, 이는 기상청에서 제공하는 일최대풍속으로 산출하였기 때문에 누락되는 풍속이 있을 수 있다고 판단되었다. 따라서 분풍속을 이용하여 모든 풍향의 일최대풍속을 구하였고, Weibull 분포를 통해 재현기대풍속을 산출하였다. 최종적 으로 기상청에서 제공하는 일최대풍속으로 구한 풍향계수와 분풍속으로 구한 일최대풍속의 풍향계수를 비교하여 지역별 풍향계수의 경향 및 두 방법의 차이점에 대해 분석하였다.

최근 3차원 영상 데이터 활용 기술이 주목받으며 레이저 스캐너, 깊이 카메라와 같은 장비를 활용하여 작물의 생육을 측정하려는 연구가 시도되고 있다. 작물의 생육 특성을 측정할 때 3차원 영상 데이터를 활용한다면 평면 데이터에서 측정하지 못한 구조와 형태 정보를 이용할 수 있는 장점이 있다. 본 연구에서는 콩의 생육 특성을 3차원 영상 데이터를 활용하여 추정하였다. 깊이 카메라를 이용하여 콩의 개화시(R1), 착협기(R3), 종실비대기(R5) 에 촬영하고 3차원 데이터로 개체의 초장과 엽면적을 추정하고 실측 값과 비교하였다. 초장 추정을 위해 평면에 투영된 개체의 무게 중심을 이용하여 원줄기의 x, y 좌표 위치를 지정하였는데 눈으로 보고 지정한 원줄기의 위치와 무게 중심 점의 x, y 좌표 위치는 높은 결정 계수를 보였다. 초장 추정의 경우 콩의 구조와 형태가 발달함에 따라 3차원 영상에서 지면으로부터 개체 상단 지점 간 거리를 이용하는 방법은 실측과 추정 값간 오차가 컸다. 엽면적 추정을 위해서 3차원 위치 값을 갖는 개체 표면 점들을 높이에 따라 분할하고 각 높이 구간의 면적을 계산하였다. 3차원 데이터 병합 과정에서 늘어난 점 개수로 인해 각 높이 구간에서 계산된 면적이 증가하였기 때문에 추정 값은 과대평가되었다. 향후 3차원 영상을 이용한 보다 정밀한 생육 조사를 위해서는 작물 고유의 생육변수 특성을 고려한 데이터 전처리 과정과 분석 방법 개발이 필요할 것으로 사료된다.