The 81mm mortar barrel is a precision component requiring exact internal diameter measurements, which poses challenges in both machining and inspection using conventional equipment. This study addresses issues related to measurement variability and reprocessing due to inconsistencies in bore measurements along different barrel positions. Using Gage R&R analysis, we identified the limitations of the existing measurement system, particularly its inability to provide consistent and detailed readings along the full barrel length. To resolve these challenges, a revised measuring system was developed and compared with the existing system, showing enhanced accuracy and reduced errors. The improved system was subsequently applied to the barrel machining process, resulting in quality improvements in the final product.

PURPOSES : The reliability of traffic volume estimates based on location intelligence data (LID) is evaluated using various statistical techniques. There are several methods for determining statistical significance or relationships between different database sets. We propose a method that best represents the statistical difference between actual LID-based traffic volume estimates and the VDS values (i.e., true values) for the same road segment. METHODS : A total of 2,496 datasets aggregated for 1-h LID and VDS data were subjected to various statistical analyses to evaluate the consistency of the two datasets. The VDS data were defined as the true values for comparison. Four different statistical techniques (procrutes, 2-sample t-test, paired-sample t-test, and model performance rating scale) were applied. RESULTS : In cases where there is a specific pattern (e.g., traffic volume distribution considering peak and off-peak times), distribution tests such as Procrustes or Kolmogorov-Smirnov are useful because not only the prediction accuracy but also the similarity of the data distribution shape is important. CONCLUSIONS : The findings of this study provide important insight into the reliability of LID-based traffic volume estimation. To evaluate the reliability between the two groups, a paired-sample t-test was considered more appropriate than the performance evaluation measure of the machine-learning model. However, it is important to set the acceptance criteria necessary to statistically determine whether the difference between the two groups in the paired-sample t-test varies according to the given problem.

목적 : 본 연구는 입체시 검사법들의 재현성과 교환가능성에 대해 알아보고자 하였다. 방법 : 안과적 질환과 관련된 진단을 받은 적이 없으며 교정시력이 20/20 이상인 30명을 대상으로 하였다. 굴 절이상을 확인한 후 입체시 검사(티트무스, 랑 Ⅱ, 티엔오, 프리즈비 검사)를 각각 하루 이상의 간격을 두고 두 번 검사하였다. 검사 간의 신뢰도 분석은 급내상관계수를 이용하여 분석하였다. 결과 : 반복 검사를 통한 입체시 검사의 신뢰도 확인에서 프리즈비 검사(p=0.103, ICC=0.99) 에서만 높은 재 현성을 보였다. 입체시 검사 간의 비교에서는 프리즈비와 티엔오 검사(p=0.358, ICC=0.89)에서 좋은 호환성을 확 인할 수 있었다. 20초미만의 작은 차이를 나타내는 경우 또한 42%로 모든 검사법들의 비교 중 가장 큰 비중을 차 지하는 것으로 나타났다. 결론 : 입체시 검사의 진행은 방문 간에 일정하게 유지되는 것이 좋으나 검사 방법들의 특성에 따라 신뢰도와 호환성이 좋은 입체시 검사와 함께 평가되는 것이 필요하다. 본 연구의 결과 프리즈비 검사가 신뢰도와 호환성에서 좋은 것으로 나타나 다른 검사와 함께 평가하는 것이 유용할 것으로 사료된다.

This paper chronicles the evolution of load-sharing parameter estimation methodologies, with a particular focus on the significant contributions made by Kim and Kvam (2004) and Park (2012). Kim and Kvam's pioneering work underscored the inherent challenges in deriving closed-form solutions for load-share parameters, which necessitated the use of sophisticated numerical optimization techniques. Park's research, on the other hand, provided groundbreaking closed-form solutions and extended the theoretical framework to accommodate more general distributions of component lifetimes. This was achieved by incorporating EM-type methods for maximum likelihood estimation, which represented a significant advancement in the field. Unlike previous efforts, this paper zeroes in on the specific characteristics and advantages of closed-form solutions for load-share parameters within reliability systems. Much like the basic Economic Order Quantity (EOQ) model enhances the understanding of real-life inventory systems dynamics, our analysis aims to thoroughly explore the conditions under which these closed-form solutions are valid. We investigate their stability, robustness, and applicability to various types of systems. Through this comprehensive study, we aspire to provide a deep understanding of the practical implications and potential benefits of these solutions. Building on previous advancements, our research further examines the robustness of these solutions in diverse reliability contexts, aiming to shed light on their practical relevance and utility in real-world applications.

본 연구는 기혼 여성의 가사분담 어려움, 양육 어려움, 경제 수준이 추 가 출산 의향에 미치는 영향에서 사회 신뢰도의 조절효과를 검증하는 것 에 목적이 있다. 연구자료는 한국보건사회연구원에서 실시한 2021 가족 과 출산 조사 자료를 기반으로 하였으며, 연구대상은 20대~40대 기혼 여 성 2,064명이다. 연구 목적에 따른 분석을 위해 SPSS 25.0을 활용하였 으며 빈도 분석, 기술통계, 상관관계, 인과관계 분석을 진행하였다. 연구 결과 가사분담 어려움이 적을수록, 양육 어려움이 적을수록, 사회 신뢰도 가 높을수록 추가 출산에 영향이 있었다. 특히 평균중심화를 통하여 확 인한 사회 신뢰도의 조절효과로 가사분담 어려움과 사회 신뢰도의 상호 작용, 양육 어려움과 사회 신뢰도의 상호작용이 기혼 여성의 추가 출산 의향에 영향을 미쳤다. 이에 가사분담 어려움과 양육 어려움 해소, 사회 신뢰도 증진을 위한 정책 및 실천적 함의를 제시했다.

목적: 본 연구의 목적은 뇌손상 환자의 자기인식 정도를 측정하기 위해 Prigatano 등(1986)이 개발한 Patient Competency Rating Scale (PCRS)를 한국어로 번안한 Korean version of the Patient Competency Rating Scale (K-PCRS)의 타당도 및 신뢰도를 연구하기 위함이다. 연구방법: PCRS 원 문항에 대해 번역 및 역번역 과정, 사전 이해도 검증, 문항 적합성 검증을 거쳐 K-PCRS의 예비문항을 구성하였고, 실험군 뇌손상 환자 62명, 보호자 60명, 치료사 62명을 대상으로 수집한 자료에 대해 신뢰도를 분석하였다. 또한 구성타당도 검증을 위해 탐색적, 확인적 요인분석 및 K-PCRS와 우울증과의 상관성을 확인하였으며, 대조군 참여자 60명과 참여자 가족 60명을 비교하여 K-PCRS의 변별타당도를 확인하였다. 결과: 탐색적 요인분석 결과, 5개 요인이 추출되었으나 마지막 요인에서 0.40이상의 요인 부하량이 확인되지 않아, 원척도에서 제시한 4요인을 고정하여 분석하였고 확인적 요인분석 결과 적정수준의 적합도를 보여 K-PCRS의 4요인 모형이 지지되었다. 또한 K-PCRS와 K-BDI의 상관성 분석결과 K-PCRS의 환자-보호자의 불일치 점수와 K-BDI와의 상관계수는 0.2, 환자-치료사의 불일치 점수와 Korean-Beck Depression Inventory (K-BDI)와의 상관계수는 0.4로 모두 음의 상관성을 보였다. 대조군과의 비교를 통한 변별타당도 분석결과 실험군과 대조군의 K-PCRS 총점은 유의한 차이가 있었으며(p < 0.05) 실험군의 환자-보호자 불일치 평균과 대조군의 참가자-가족의 불일치 평균에서도 유의한 차이가 있었다(p < 0.05). 신뢰도 분석 결과 환자용, 보호자용, 임상가용 K-PCRS의 Cronbach α계수는 환자용 0.947이었고, 보호자용 0.946, 임상가용 0.958로 높은 상관계수를 보였다. 결론: 본 연구에서 K-PCRS의 타당도 및 신뢰도를 확인하였으며, 향후 뇌손상 환자의 자기인식 정도를 객관적으로 평가하기 위해 K-PCRS가 활용될 수 있기를 기대한다.

It is considered that a skincare shop is one of important places for skincare and beauty care. Due to increasing daily stress and environmental pollution recently, healthy skin is getting important and more people are visiting skincare shops. This study investigated the effects of laporte of skincare shop workers on customer reliability and satisfaction with a focus on women in twenties and thirties, and those of reliability on customer satisfaction, aiming at providing basic information for active management of skincare shops. For the purposes, this study used a questionnaire to collect the data and using SPSS 25.0. conducted a frequency test, an exploratory factor analysis, a descriptive statistical analysis, a correlation analysis and a reliability test to analyze the data collected. As a result of the study, it was discovered that laporte of skincare shop workers had a significant effect on customer reliability and satisfaction and reliability had a significant effect on customer satisfaction. It suggested that relationship between skincare shop workers and customers is very important for skincare shop management.

Objective: This study aimed to translate and validate the Motivation to Change Lifestyle and Health Behaviors for Dementia Risk Reduction (MCLHB-DRR) scale among middle-aged and older Korean adults. Methods: This study included a sample of Korean adults aged ≥ 50 years recruited from an online panel. Content and construct validity were examined to determine the scale’s validity. Internal consistency and test-retest reliability were examined to determine its reliability. Results: A total of 270 participants completed the questionnaire. Content validity was determined by professors and researchers of occupational therapy. One item was deleted during the content validity assessment. The confirmatory factor analysis results showed a good model fit (χ 2/degree of freedom = 1.845, comparative fit index = 0.939, Tucker-Lewis index = 0.929, root mean square error of approximation = 0.056). Cronbach’s alpha values were 0.821 - 0.900, indicating good internal consistency. The test and retest scores did not differ significantly. Conclusion: The Korean version of the MCLHB-DRR scale has validity and reliability for use among the Korean population, to assess beliefs and attitudes toward lifestyle change to reduce the risk of dementia.

본 연구에서는 20∼50대 성인 여성을 대상으로 SNS를 통한 네일샵의 활용실태 및 SNS 정보 신뢰도와 네일샵 선택요인에 미치는 영향을 알아보고, SNS를 통한 효과적인 홍보를 통하여 고객 만족과 충성고객 확보 및 네일업계의 경영전략에 기여 하고자 연구를 진행하였다. 설문 조사는 SNS를 사용하며 네일샵을 이용해 본 20∼50대 성인 여성을 대상으로 최종 403부를 분석하여 사용하였다. 연구 결과, 일반 적 특성에 따른 SNS를 통한 네일샵의 이용실태에서는 각 요인에 따라 차이가 있는 것으로 나타났으며, SNS를 통한 네일샵 이용실태에 따른 정보 신뢰도와 SNS 네일샵 선택요인, 네일샵 SNS 활용에 따른 SNS 정보 신뢰도, 네일샵 선택요인에 차이가 있는 것으로 나타났다. 또한, SNS 정보 신뢰도가 SNS를 통한 네 일샵 선택요인에 영향을 미치는 것으로 나타났다. 본 연구는 네일샵 경영전략 수립을 위한 마케팅의 기초 자료 및 네일샵을 이용하는 소비자들의 만족도를 높여 네일 미용 시장의 활성화에 도움이 될 수 있을 것이 다.

The design variables and material properties as well as the external loads concerned with structural engineering are used to be deterministic in optimization process. These values, however, have variability from expected performance. Therefore, deterministic optimum designs that are obtained without taking these uncertainty into account could lead to unreliable designs, which necessitates the Reliability-Based Design Optimization(RBDO). RBDO involves an evaluation of probabilistic constraints which constitutes another optimization procedure. So, an expensive computational cost is required. Therefore, how to decrease the computational cost has been an important challenge in the RBDO research field. Approximation models, response surface model and Kriging model, are employed to improve an efficiency of the RBDO.

본 논문에서는 신뢰성 기반 최적설계(RBDO)에서 성능함수의 비선형성을 고려한 효율적인 차원감소법(DRM)을 제안한다. 차원감 소법은 적분직교점과 가중치를 사용하여 1차 신뢰도법(FORM) 보다 더 정확하게 신뢰도를 평가하는 반면 성능함수를 추가로 해석해 야하기 때문에 적분직교점의 개수가 증가하면 효율성이 저해된다. 본 논문에서는 신뢰성 기반 최적설계에서 성능함수의 비선형도를 평가하고, 비선형도에 따라 적분직교점의 수를 결정하는 기준을 제안한다. 이를 통해 신뢰성 기반 최적설계가 진행될 때 반복마다 적 분직교점의 수를 조절하여 차원감소법의 정확도는 유지하면서 계산의 효율성은 개선하는 방안을 제안한다. 성능함수의 비선형도 평 가는 최대가능목표점(MPTP) 탐색에 사용한 벡터 사이의 각도를 통해 이루어지며, 수치 테스트를 통해 비선형도에 따른 적절한 적분 직교점의 수를 도출하였다. 2차원 수치예제를 통해 개발된 방법이 차원감소법이나 몬테카를로 시뮬레이션(MCS)의 정확도는 유지하 면서 효율성이 향상된다는 것을 확인하였다.

PURPOSES : We propose a framework to evaluate the reliability of integrating homogeneous or heterogeneous mobility data to produce the various data required for greenhouse gas emission estimation. METHODS : The mobility data used in the framework were collected at a fixed time from a specific point and were based on raster data. In general, the traffic volume for all traffic measurement points over 24 h can be considered raster data. In the future, the proposed framework can be applied to specific road points or road sections, depending on the presence or absence of raster data. RESULTS : The activity data required to calculate greenhouse gas emissions were derived from the mobility data analysis. With recent developments in information, communication, and artificial intelligence technologies, mobility data collected from different sources with the same collection purpose can be integrated to increase the reliability and accuracy of previously unknown or inaccurate information. CONCLUSIONS : This study will help assess the reliability of mobility data fusion as it is collected on the road, and will ultimately lead to more accurate estimates of greenhouse gas emissions.

In this study, we report the microstructural evolution and shear strength of an Sn-Sb alloy, used for die attach process as a solder layer of backside metal (BSM). The Sb content in the binary system was less than 1 at%. A chip with the Sn-Sb BSM was attached to a Ag plated Cu lead frame. The microstructure evolution was investigated after die bonding at 330 °C, die bonding and isothermal heat treatment at 330 °C for 5 min and wire bonding at 260 °C, respectively. At the interface between the chip and lead frame, Ni3Sn4 and Ag3Sn intermetallic compounds (IMCs) layers and pure Sn regions were confirmed after die bonding. When the isothermal heat treatment is conducted, pure Sn regions disappear at the interface because the Sn is consumed to form Ni3Sn4 and Ag3Sn IMCs. After the wire bonding process, the interface is composed of Ni3Sn4, Ag3Sn and (Ag,Cu)3Sn IMCs. The Sn-Sb BSM had a high maximum shear strength of 78.2 MPa, which is higher than the required specification of 6.2 MPa. In addition, it showed good wetting flow.

This study was conducted to verify the reliability of volatile organic compounds (VOCs) data derived from Selected Ion Flow Tube-Mass Spectrometers (SIFT-MS) measurements. In the previous study, the measurement reliability was validated using simultaneous measurements by SIFT-MS and gas chromatography-mass spectrometry (GS-MS), but in order to ensure more accuracy, and additional analysis was conducted by diluting standard gases (2 ppm) consisting of 10 types of VOCs mainly measured in industrial complexes (concentrations ranged from 0 to 500 ppb). As a result of 2 experiments, the SIFT-MS showed linearity and produced a coefficient of determination of over 0.99 for all cases. SIFT-MS has secured high measurement reliability, and it is considered to be able to efficiently manage VOCs emitted in industrial complexes.

Abstract Purpose : The purpose of this study is to evaluate the differences and reliability of various methods for measuring Interpupillary Distance. Methods : The participants were 50 Cambodian adults (28.08±3.85 years old) without ocular disease and abnormal binocular vision. Far/near IPD was measured using Corneal reflection pupillometer, PD ruller and spotting, and calculated formula for fixation distance. Using each method, the pupil distance of both eyes was measured three times, respectively, and the average value was recorded. Results : The average value of the corneal reflection pupilometer in the distance was 63.08±3.42 mm, the average value of PD calculated formula was 62.97±3.41 mm, the average value of the PD ruler was 63.72±3.17 mm, and the average value of the spotting method was 63.89±3.15 mm. The average value of the corneal reflection pupilometer in the near was 59.85±3.23 mm, the average value of the calculated formula for fixation distance was 59.95±3.23 mm, the average value of PD ruler was 59.72±3.29 mm, and the average value spotting method was 59.47±3.23 mm. Comparison between various methods in the distance and near showed statistically significant differences (p<0.001). Conclusion : In the comparative analysis between each method, the corneal reflection pupillometer is considered to be the most accurate method, but since there is no significant difference from the average value of the Spotting method, the PD Ruler Viktorin method, and the calculated formula for fixation distance, whichever method is used, it is clinically acceptable. Therefore it is believed that each method is compatible with each other. Key words : Corneal reflection pupillometer, PD meter, PD ruler, Spotting

Recently, due to the expansion of the logistics industry, demand for logistics automation equipment is increasing. The modern logistics industry is a high-tech industry that combines various technologies. In general, as various technologies are grafted, the complexity of the system increases, and the occurrence rate of defects and failures also increases. As such, it is time for a predictive maintenance model specialized for logistics automation equipment. In this paper, in order to secure the operational safety and reliability of the parcel loading system, a predictive maintenance platform was implemented based on the Naive Bayes-LSTM(Long Short Term Memory) model. The predictive maintenance platform presented in this paper works by collecting data and receiving data based on a RabbitMQ, loading data in an InMemory method using a Redis, and managing snapshot DB in real time. Also, in this paper, as a verification of the Naive Bayes-LSTM predictive maintenance platform, the function of measuring the time for data collection/storage/processing and determining outliers/normal values was confirmed. The predictive maintenance platform can contribute to securing reliability and safety by identifying potential failures and defects that may occur in the operation of the parcel loading system in the future.

Regulatory agencies require burn-up verification to ensure that dry storage casks using burn-up credit are not loaded with fuel with a reactivity greater than the allowable standard. Accordingly, in preparation for dry storage of SF, the reliability of the burnup was verified and action plans for fuel with confirmed errors were reviewed. Reliability verification was performed by comparing the actual burnup calculated with combustion calculation code (TOTE, ISOTIN) used in NPP and the design burnup calculated with the nuclear design code (ANC). As a result of comparing the differences between actual burnup and design burnup for 7,414 assemblies of SF generated from CE-type NPPs, the average deviation was confirmed to be 0.79% and 220 MWD/MTU. In the CE-type NPPs, no fuel showing large deviations was identified, and it was confirmed that reliability was secured. As a result of comparing the differences in 11,082 assemblies of SF generated from WH-type NPPs, the differences were not large, averaging 1.16% or 422 MWD/MTU. However, fuels showing significant differences were identified, and cause analysis was performed for those fuels. The cause analysis used a method of comparing the burnup of symmetrically loaded fuels in the reactor. For fuels that were not symmetrically loaded, a method was used to compare them with fuels with similar combustion histories. As a result of the review, it was confirmed that the fuel was under- or over-burned compared to symmetrically loaded fuel. For fuels for which clear errors have been identified, we are considering replacing them with the design burnup, and for fuels whose causes cannot be confirmed, we are considering ways to maintain the actual burnup.