PURPOSES : Driving simulations are widely used for safety assessment because they can minimize the time and cost associated with collecting driving behavior data compared to real-world road environments. Simulator-based driving behavior data do not necessarily represent the actual driving behavior data. An evaluation must be performed to determine whether driving simulations accurately reflect road safety conditions. The main objective of this study was to establish a methodology for assessing whether simulation-based driving behavior data represent real-world safety characteristics. METHODS : A 500-m spatial window size and a 100-m moving size were used to aggregate and match the driving behavior indicators and crash data. A correlation analysis was performed to identify statistically significant indicators among the various evaluation metrics correlated with crash frequency on the road. A set of driving behavior evaluation indicators highly correlated with crash frequency was used as inputs for the negative binomial and decision tree models. Negative binomial model results revealed the indicators used to estimate the number of predicted crashes. The decision-tree model results prioritized the driving behavior indicators used to classify high-risk road segments. RESULTS : The indicators derived from the negative binomial model analysis were the standard deviation of the peak-to-peak jerk and the time-varying volatility of the yaw rate. Their importance was ranked first and fifth, respectively, using the proposed decision tree model. Each indicator has a significant importance among all indicators, suggesting that certain indicators can accurately reflect actual road safety. CONCLUSIONS : The proposed indicators are expected to enhance the reliability of driving-simulator-based road safety evaluations.

라멘 구조는 건설 분야에서 가장 널리 쓰이는 구조 형식이다. 그러나 최대 부모멘트가 발생하는 우각부에서 적절한 세부 검토 가 필요하다. 따라서 적절한 휨강도 및 휨강성을 보유한 연결구조가 필요하며, 이에 적합하지 않을 경우 우각부 볼트 배치를 회피하여야 한다. 이 연구에서는 휨강도, 휨강성 및 시공안전성 등의 구조적 성을 개선하기 위해 특수한 형식의 우각부 볼트 연결 방식을 제안하였 으며, 기존 및 제안한 볼트 연결 방식이 적용된 강재 라멘 구조에 대한 휨강도실험을 수행하였다. 실험 결과, 제안한 우각부 볼트 연결 방식은 기존 방식에 비해 휨성능이 우수한 것으로 나타났으며, 하부구조 전면에 헌치를 설치할 경우 휨성능이 더욱 증대되는 것으로 나타 났다.

As the demand for lithium-ion batteries for electric vehicles is increasing, it is important to recover valuable metals from waste lithium-ion batteries. In this study, the effects of gas flow rate and hydrogen partial pressure on hydrogen reduction of NCM-based lithium-ion battery cathode materials were investigated. As the gas flow rate and hydrogen partial pressure increased, the weight loss rate increased significantly from the beginning of the reaction due to the reduction of NiO and CoO by hydrogen. At 700 °C and hydrogen partial pressure above 0.5 atm, Ni and Li2O were produced by hydrogen reduction. From the reduction product and Li recovery rate, the hydrogen reduction of NCM-based cathode materials was significantly affected by hydrogen partial pressure. The Li compounds recovered from the solution after water leaching of the reduction products were LiOH, LiOH·H2O, and Li2CO3, with about 0.02 wt% Al as an impurity.

구조물 보수 부위의 손상, 재 박리 등의 2차 피해가 이어지며, 보수 부위의 새로운 거동 평가 기법 에 대한 연구의 필요성이 대두되고 있다. 현재 구조물 보수 부위의 거동을 알기 위해서 주로 인력 중 심의 구조물 외관 검사를 진행하고 있으나, 단편적인 검사 결과를 얻게 되어 지속적이고 세밀한 점검 이 어려운 실정이다. 따라서, 본 연구에서는 탄소나노튜브 기반 폴리머 콘크리트를 활용해 압축과 같 은 외부 응력에 대한 탄소나노튜브 함량별 전기적 변화를 분석하였으며, 균열이 발생한 콘크리트 구조 물을 보수 후 응력을 가해 거동에 따른 전기적 변화를 평가하였다. 압축 시험 결과, 응력에 따른 탄소 나노튜브 기반 폴리머 콘크리트의 전기 저항이 감소하며, 탄소나노튜브 함량이 낮을수록 응력에 대한 저항 감소 폭이 넓게 나타나며 민감도가 증가하였다. 균열 보수 시험 결과, 보수 부위에 응력이 가해 졌을 때 전기 저항이 감소해 앞서 진행된 실험 결과와 동일한 경향을 보였으며, 또한 응력이 가해지지 않을 때 초기 저항으로 회복하는 경향을 보여 구조물 보수 부위 거동에 대한 평가가 가능한 것으로 검 증되었다. 이를 통해, 탄소나노튜브 기반 폴리머 콘크리트는 구조물에 적용이 가능하며, 구조물 보수 후에도 가해지는 응력에 대한 지속적인 감지가 가능해 보수 부위 거동 평가가 가능할 것으로 판단된다.

형상기억합금(Shape Memory Alloy, SMA)은 소성변형이 일어나도 냉각 및 가열을 통해 기존 형상 으로 돌아갈 수 있는 형상기억효과(Shape Memory Effect, SME)를 가진 재료이다. 이를 통해 사전에 인장 변형된 SMA를 구속 후 가열하면 SME에 의해 원래 형태로 돌아가려 하지만, 변형이 구속되어 회복 응력이라 하는 압축 응력이 발생한다. 따라서 사전 변형된 SMA를 구조물에 적용하게 되면 셀프 -프리스트레싱을 도입할 수 있다. 그중 철을 기반으로 제작된 Fe-SMA는 다른 SMA에 비해 높은 경 제성을 가져 건설 재료로써 많은 관심을 받고 있다. 이에 Fe-SMA를 철근콘크리트(Reinforced Concrete, RC) 구조물에 적용한 많은 연구가 진행되었으며, 구조성능이 향상되는 것을 확인하였다. 그러나 Fe-SMA가 사용된 RC 구조물의 피로 실험에 관한 연구는 부족한 실정이다. 따라서 본 연구에서는 Fe-SMA 바를 인장재로 사용한 RC 보의 피로 성능을 평가하였고 하중 유형(정적, 피로)과 피로 응력 범위를 변수로 고려해 고주기 피로 실험을 수행하였다. 이를 통해 피로 강도, 피로 수명 및 거동을 확 인하였으며, Fe-SMA 바를 인장재로 사용한 RC 보의 피로강도는 최대하중의 40%~60% 사이에 있을 것으로 예측되었다.

본 논문은 CFRP 그리드의 정착길이에 따른 콘크리트 보의 휨거동을 평가한 실험적 연구를 보고한다. 실험을 위해 폭 250 mm, 높이 125 mm, 길이 2000 mm의 실험체가 제작되었다. 실험변수로 CFRP 그리드의 정착길이(1000 mm, 800 mm, 700 mm, 600 mm, 500 mm, 400 mm, 300 mm, 200 mm)가 고려되었다. 실험체 제작 후 3점 휨실험이 수행되었다. 실험결과 모든 실 험체의 강성은 정착길이에 영향을 받지 않고 유사한 것으로 나타났다. 초기 균열하중은 모든 실험체에서 유사하게 나타났으나, 정착길이가 감소됨에 따라 최대하중, 최대하중 시의 처짐 및 변형률은 감소하는 경향을 나타냈다. 특히 부재 길이에 80% 이상 이 정착된 경우 부재 길이와 동일한 정착길이를 가진 콘크리트 보의 약 90% 이상의 구조성능을 확보할 수 있는 것으로 확인되 었다. 제안된 수치해석 모델은 CFRP 그리드의 정착길이가 감소됨에 따른 극한하중의 저하를 유사하게 예측하였으며, 극한하중 의 오차는 평균 13.1%로 CFRP 그리드의 정착길이에 따른 콘크리트 보의 휨성능을 비교적 정확하게 예측하는 것으로 나타났다.

A checklist of dietary behavior items for the elderly was developed based on Korean dietary guidelines. First, a literature review was conducted, and 63 preliminary items, including 30 items on food intake, 12 on eating habits, and 21 on dietary culture, were obtained to evaluate the dietary guidelines. The preliminary items were evaluated by experts using Lawshe’s method to verify the content validity. They were then revised, resulting in 52 items: 25, 11, and 16 in the food intake, eating habits, and dietary culture domains, respectively. A face-to-face survey was conducted on 331 people over 65 years of age in the metropolitan area, and their one-day food intake was surveyed using a 24-hour recall method in August 2022. The 48 items, including 24, 11, and 13 items on food intake, eating habits, and dietary culture, respectively, correlated significantly with the evaluation indicators of nutrient intake, such as mean adequacy ratio, dietary diversity score, and nutrient intake density. These items were considered suitable for evaluating the elderly's compliance with dietary guidelines.

본 연구는 경로당을 이용하는 노인들을 대상으로 ICT기반 치매예방 통합프로그램을 적용하여 활력, 치매두려움 및 치매예방행위에 미치는 영향을 파악하고자 시도되었다. 프로그램 구성은 주 2회, 6주, 회기당 30분 분량으로 총 12회차이며 단일군 전후 실험설계이다. 자료분석은 기술통계, Paired t-test, Pearson's correlation coefficient를 이용하였다. ICT기반 치매예방 통합프로그램은 경로당 노인의 활력과 치매예방행위를 증가시키고, 치매두려움은 감소시키는 것으로 나타났다. 이러한 연구결과를 통해 ICT기반 치매예방 통합프로그램을 경로당 이용노인의 치매예방를 위해 실무현장에서 활용할 것을 권장한다.

This study was conducted to investigate whether there were differences in eco-friendly food, home meal replacement (HMR) purchases, and eating-out behavior according to the level of agri-food consumer competence. The data for the study were extracted from main food consumers (n=3,321) in the 2022 Food Consumption Behavior Survey. The competence index was divided into awareness-attitude-practice items, and three groups were classified by competence level. The results showed an agri-food consumer competency score of 70.62, with the highest score for awareness (73.96), followed by practice (69.28) and attitude (66.18). The frequency of purchasing eco-friendly food was higher in the excellent group compared to other groups, and quality and price satisfaction was higher with higher competency (p<0.001). Regarding HMR, the results showed that the shortage group had the lowest HMR consumption rate, and satisfaction decreased as competence decreased (p<0.001). The main reason for eating-out was to enjoy food in all groups (59.0%), followed by a lack of cooking time in the excellent group (15.7%) and hassle with food preparation in the moderate and shortage groups (17.3%, 16.6%) (p<0.001). In short, agri-food consumption competency showed differences by contents and components, and differences in food purchases and eating-out behavior by competency level were found.

Molten Salt Reactor, which employs molten salt mixture as fuel, has many advantages in reactor size and operation compared to conventional nuclear reactor. In developing Molten Salt Reactor, the behavior of fission product in operation should be preliminary evaluated for the correct design of reactor and its associated system including off-gas treatment. In this study, for 100 Mw 46 KCl- 54 UCl3 based Molten Salt Reactor with operating life time of 20 year, the fission product behavior was estimated by thermodynamic modeling employing FactSage 8.2. Total inventory of all fission product were firstly calculated using OpenMC code allowing depletion during neutronic calculation. Then, among all inventory, 46 element species from Uranium to Holmium were chosen and given to the input for equilibrium module of Factsage with its mass. In phase equilibrium calculation, for the correct description of solution phase, KCl-UCl3 solution database based on modified quasichemical model in the quadruplet approximation (ANL/CFCT-21/04) was employed and the coexisting solid phase was assumed to pure state. With the assumption of no oxygen and moisture ingress into reactor system, equilibrium calculation showed that 1% of solid phase and of gas phase were newly formed and, in gas phase, major species were identified : ZrCl4 (47%), Xe (33%), UCl4 (14%), Kr (5%), Ar (1%) and others. This result reveals that off-gas treatment of system should account for the appropriate treatment of ZrCl4 and UCl4 besides treatment of noble gas such as Xe and Kr.

User churn in games often arises due to inadequate game difficulty. To address this, non-player characters (NPCs) has been utilized to modulate difficulty according to individual game skill. Nevertheless, the effectiveness of solely NPC-based adjustments is limited since game difficulty is influenced by both NPCs and environmental factors. This paper introduces a novel method for dynamically tailoring game difficulty by adjusting in-game environments based on player behavior patterns in top-down shooter game. Through analysis of diverse user game play data, we find that factors within the game environment, such as the distribution of enemy characters and the arrangement of terrain, have a substantial influence on the level of difficulty. Furthermore, it has been observed that behavioral patterns of players show variations according to changes in the game environment. Using these analytical result, we devise an artificial neural network model that configures an environment that suit player behavior patterns. With the model, we figure out the user player pattern and control the difficulty dynamically by changing the environment factors. Through the experiments, we show that our method provides an appropriate level of difficulty for users to prevent user churn.

This study examined the determinants of healthy food purchases before and after COVID-19 in Korea. Binomial and multinomial logistic regression models were applied to Korea Rural Economic Institute's Food Consumer Behavior Survey data from 2019 to 2021. The analysis revealed a significant decrease in the non-intake of healthy food in 2021 compared to 2019, suggesting the impact of COVID-19 on healthy food consumption. Consumption patterns also changed, with a decrease in direct purchases and an increase in gift-based purchases. Several variables showed significant effects on healthy food intake. Single-person households exhibited a higher probability of eating healthy food after COVID-19. The group perceiving themselves as healthy had a lower likelihood of consuming healthy food pre-COVID-19, but this changed after the pandemic. Online food purchases, eco-friendly food purchases, and nut consumption showed a gradual decrease in the probability of non-intake over time. Gender and age also influenced healthy food intake. The probability of eating healthy food increased in the older age group compared to the younger group, and the probability increased significantly after COVID-19. The probability of buying gifts was significantly higher in those in their 60s, indicating that the path to obtaining healthy food differed by age.

The purpose of this study was to investigate the association between household economic changes by COVID-19 and dietary habits in Korean adolescents. The study analyzed data from the 17th Korea Youth Risk Behavior Survey in 2021. A total of 54,848 middle and high school students, 28,401 males and 26,447 females, participated in this study. COVID-19 lead to deterioration of household economy in the lower level of household economic status (p<0.001). The deterioration of household economic status by COVID-19 was associated with dietary habits such as lower breakfast intake, and higher fast food, soda drinks, and sweet drinks consumption (p<0.001). Logistic regression analysis showed that deterioration of household economic status was significantly decreased in frequency of breakfast intake (OR: 0.73, 95% CI: 0.67~0.80). The deterioration of household economic status by COVID-19 was also significantly associated with increased frequency of fast food (OR: 1.28, 95% CI: 1.16~1.41), soda drinks (OR: 1.42, 95% CI: 1.30~1.56) and sweet drinks (OR: 1.35, 95% CI: 1.24~1.46) consumption (p<0.001). In conclusion, it was confirmed that the change in household economy caused by COVID-19 was associated with dietary habits in adolescents. As the household economy deteriorated, there was an increase in undesirable dietary habits including skipping breakfast and fast food consumption.

From the standpoint of developing a transformative service to create improvements in collective wellbeing (Anderson & Ostrom, 2015), evidence of a sport–resilience relationship is gradually accumulating in the literature (Kim et al., 2022). Sport management and social science scholars are making considerable efforts to understand how sport entities with transformative services can contribute to consumer resilience—an intervention through a sport consumption experience that affects people’s abilities to cope with adversity (Inoue et al., 2022; MacIntosh et al., 2020). However, little is known about the sport industry and spatial consumer behavior in terms of consumer resilience. Although previous researchers have identified a macro-level association between sport industry and community resilience from a bird's eye view (Kim et al., 2021), it could not determine how and where sport industry at a macro level can be related to individual-level resilience through metaphors of Consumer Desire. Specifically, the spatial patterns of sport consumption (i.e., consumer spatial behavior) can be a result of sport consumer behavior affected by spatial context upon heterogeneous features of sport industry across regions (Kim et al., 2021) in the environment–behavior paradigm (Olsson & Gale, 1968). The macrolevel clustering of the sport industry in a region (environment) can be a community resource to provide individuals with the opportunity for sport consumption (behavior), which promotes the micro-level psychosocial factors for sport consumer resilience (Inoue et al., 2022). Furthermore, recent work illustrates heterogeneous spatial interaction at the regional level of the sport industry and individual-level sport consumption (Kim et al., 2022), suggesting the elaboration of cross-level spatial interaction models (Kim et al., 2021). Accordingly, in this study we aim to not only (a) determine spatially heterogeneous interactions in the association between sport industry and consumer spatial behavior in affecting consumer resilience, but also (b) identify what effect spatial interaction has on cross-level relationships. Using data focused on a multiscale-based nested geographic structure (e.g., individual-level consumption by zip code, county, state, and nation) that could elucidate the sport consumer spatial behavior, We collected multiple types of data from Florida, including the location quotient of the main seven sport industries (e.g., sport facilities) and socioeconomic factors (e.g., social vulnerability) at the county level from secondary sources. In addition, we acquired individual-level data from Qualtrics panels (1,107 Florida residents) to measure sport consumer spatial behavior (e.g., location-based sport consumption experience) and consumer resilience using the Connor-Davidson Resilience Scale. To address spatial interaction and heterogeneity, we used a comprehensive analytical model for global and local spatial analysis, including a spatial multilevel mediation (SMM) model and multiscale geographically weighted regression (MGWR) model. As a result of the SMM model, the county-level cluster of sport facilities affected individual-level participatory sport consumption, which enhanced consumer resilience (cross-level interaction effect). However, considerable spatial non-stationarity appeared in the spatial interaction, indicating interregional interactions in the cross-level effects within a county. The results of MGWR indicated significant spatially heterogeneous patterns in the association between the cluster of sport facilities and participatory sport consumption. That is, it was clarified that the spatial heterogeneous effects of the clustering of sport facilities on sport consumer spatial behavior are associated with consumer resilience. This empirical interdisciplinary work, including sport management, geography, and consumer psychology, advances knowledge of consumer spatial behavior and resilience by demonstrating heterogeneous spatial interactions. Practically, the current study calls for spatial management planning and strategy in sport industry for enhancing consumer resilience through spatial sport consumption, considering spatially varying patterns.

Sustainability rears its head in the current online marketing and virtual store -research. Sustainability considerations involve pro-environmental-, social- and economic values as well as future generations and continuous innovation (Hanss and Böhm, 2012). Central in the sustainability research is sustainable consumer behavior, which has been found to be subject of intensions varying across different types of consumers, issues, and product categories (O’Rourke and Ringer, 2016). Determining consumers’ general egoistic, altruistic and biospheric values (e.g., De Groot and Steg 2008; Steg et al., 2014) have resulted quite complex and not always so generalizable structural models for sustainable behavior. While value -research has been dominant in determining the sustainability intensions and eventual behavior, there are relatively little solid theories and understating about different psychological processes behind sustainable behavior. Furthermore, the consideration of multiple sustainable consumer behavior outcomes seems to be limited, which can also hamper the development of models and theories (see e.g., Hulland and Houston 2021).

This study investigated the awareness and consumption behavior of 118 vegetarians and omnivores toward plant-based dairy alternatives. The preference and choice attribute questionnaires were compared. Significant differences were obtained between the two groups when considering the purchase experience, preference, and selection attributes of plant-based dairy alternatives. Vegetarians had more experience purchasing plant-based dairy alternative products. In both groups, environmental and animal protection were the major factors that influenced the highest response rate for purchasing plantbased dairy alternatives. The preference score of vegetarians for plant-based dairy alternative products was high, indicating that vegetarianism had a significant effect on their preference for plant-based dairy alternative products. Analysis of selection attributes revealed that price, product weight, appearance, and manufacturer were considered important by vegetarians, whereas nutritional components and labeling, manufacturing environment, composition of ingredients, and taste and texture were considered more important by the omnivores. Results of this study can be used as basic data for the future development of the fast-growing industry producing plant-based dairy alternative products.

Zirconium(Zr) alloys are commonly used in the nuclear industry for applications such as fuel cladding and pressure tubes. To minimize the levels and volumes of radioactive waste, molten salts have been employed for decontaminating Zr alloys. Recently, a two-step Zr metal recovery process, combining electrolysis and thermal decomposition, has been proposed. In the electrolysis process, potentiostatic electrorefining is utilized to control the chemical form of electrodeposits(ZrCl). Although Zr metals are expected to dissolve into molten salts, reductive alloy elements can also be co-dissolved and deposited on the cathode. Therefore, a better understanding of the anodic side’s response during potentiostatic electrorefining is necessary to ensure the purity of recovered Zr and long-term process operation. As the first step, potentiodynamic polarization curves were obtained using Zr, Nb, and Zr-Nb alloy to investigate the anodic dissolution behavior in the molten salts. Nb, which has a redox potential close to Zr, and Zr exhibit active or passivation dissolution mechanisms depending on the potential range. It was confirmed that Zr-Nb alloy also has a passivation region between -0.223 to -0.092 V influenced by the major elements Zr and Nb. Secondly, active dissolution of Zr-Nb was performed in the range of -0.9 to -0.6 V. The dissolution mechanism can be explained by percolation theory, which is consistent with the observed microstructure of the alloy. Thirdly, passivation dissolution of Zr, Nb, and Zr-Nb alloy was investigated to identify the pure passivation products and additional products in the Zr-Nb alloy case. K2ZrCl6 and K3NbCl6 were identified as the pure passivation products of the major elements. In the Zr-Nb alloy case, additional products, such as Nb and NbZr, produced by the redox reaction of nanoparticles in the high viscous salt layer near the anode, were also confirmed. The anodic dissolution mechanism of Zr-Nb alloy can be summarized as follows. During active dissolution, only Zr metal dissolves into molten salts by percolation. Above the solubility near the anode, passivation products begin to form. The anode potential increases due to the disturbance of passivation products on ion flow, leading to co-dissolution of Nb. When the concentration of Nb ion exceeds the solubility, a passivation product of Nb also forms. In this scenario, a high viscous salt layer is formed, which traps nanoparticles of Zr metal, resulting in redox behavior between Zr metal and Nb ion. Some nanoparticles of Zr and Nb metal are also present in the form of NbZr.