In the post-COVID-19, the food industry is rapidly reshaping its market structure toward online distribution. Rapid delivery system driven by large distribution platforms has ushered in an era of online distribution of fresh seafood that was previously limited. This study surveyed 1,000 consumers nationwide to determine their online seafood purchasing behaviors. The research methodology used factor analysis of consumer lifestyle and Heckman’s ordered probit sample-selection model. The main results of the analysis are as follows. First, quality, freshness, selling price, product reviews from other buyers, and convenience are particularly important considerations when consumers purchase seafood from online shopping. Second, online retailers and the government must prepare measures to expand seafood consumption by considering household characteristics and consumer lifestyles. Third, it was analyzed that consumers trust the quality and safety of seafood distributed online platforms. It is not possible to provide purchase incentives to consumers who consider value consumption important, so improvement measures are needed. The results of this study are expected to provide implications on consumer preferences to online platforms, seafood companies, and producers, and can be used to establish future marketing strategies.

PURPOSES : This study aimed to identify factors affecting the duration of traffic incidents in tunnel sections, as accidents in tunnels tend to cause more congestion than those on main roads. Survival analysis and a Cox proportional hazards model were used to analyze the determinants of incident clearance times. METHODS : Tunnel traffic accidents were categorized into tunnel access sections versus inner tunnel sections according to the point of occurrence. The factors affecting duration were compared between main road and tunnel locations. The Cox model was applied to quantify the effects of various factors on incident duration time by location. RESULTS : Key factors influencing mainline incident duration included collision type, driver behavior and gender, number of vehicles involved, number of accidents, and post-collision vehicle status. In tunnels, the primary factors identified were collision type, driver behavior, single vs multi-vehicle involvement, and vehicles stopping in the tunnel after collisions. Incidents lasted longest when vehicles stopped at tunnel entrances and exits. In addition, we hypothesize that incident duration in tunnels is longer than in main roads due to the reduced space for vehicle handling. CONCLUSIONS : These results can inform the development of future incident management strategies and congestion mitigation for tunnels and underpasses. The Cox model provided new insights into the determinants of incident duration times in constrained tunnel environments compared to open main roads.

Approximately 40,000 elevators are installed every year in Korea, and they are used as a convenient means of transportation in daily life. However, the continuous increase in elevators has a social problem of increased safety accidents behind the functional aspect of convenience. There is an emerging need to induce preemptive and active elevator safety management by elevator management entities by strengthening the management of poorly managed elevators. Therefore, this study examines domestic research cases related to the evaluation items of the elevator safety quality rating system conducted in previous studies, and develops a statistical model that can examine the effect of elevator maintenance quality as a result of the safety management of the elevator management entity. We review two types: odds ratio analysis and logistic regression analysis models.

In this study, we propose a novel approach to analyze big data related to patents in the field of smart factories, utilizing the Latent Dirichlet Allocation (LDA) topic modeling method and the generative artificial intelligence technology, ChatGPT. Our method includes extracting valuable insights from a large data-set of associated patents using LDA to identify latent topics and their corresponding patent documents. Additionally, we validate the suitability of the topics generated using generative AI technology and review the results with domain experts. We also employ the powerful big data analysis tool, KNIME, to preprocess and visualize the patent data, facilitating a better understanding of the global patent landscape and enabling a comparative analysis with the domestic patent environment. In order to explore quantitative and qualitative comparative advantages at this juncture, we have selected six indicators for conducting a quantitative analysis. Consequently, our approach allows us to explore the distinctive characteristics and investment directions of individual countries in the context of research and development and commercialization, based on a global-scale patent analysis in the field of smart factories. We anticipate that our findings, based on the analysis of global patent data in the field of smart factories, will serve as vital guidance for determining individual countries' directions in research and development investment. Furthermore, we propose a novel utilization of GhatGPT as a tool for validating the suitability of selected topics for policy makers who must choose topics across various scientific and technological domains.

In this paper, a dynamic centrifuge model test was conducted on a 24.8-meter-deep excavation consisting of a 20 m sand layer and 4.8 m bedrock, classified as S3 by Korean seismic design code KDS 17 10 00. A braced excavation wall supports the hole. From the results, the mechanism of seismically induced earth pressure was investigated, and their distribution and loading points were analyzed. During earthquake loadings, active seismic earth pressure decreases from the at-rest earth pressure since the backfill laterally expands at the movement of the wall toward the active direction. Yet, the passive seismic earth pressure increases from the at-rest earth pressure since the backfill pushes to the wall and laterally compresses at it, moving toward a passive direction and returning to the initial position. The seismic earth pressure distribution shows a half-diamond distribution in the dense sand and a uniform distribution in loose sand. The loading point of dynamic thrust corresponding with seismic earth pressure is at the center of the soil backfill. The dynamic thrust increased differently depending on the backfill's relative density and input motion type. Still, in general, the dynamic thrust increased rapidly when the maximum horizontal displacement of the wall exceeded 0.05 H%.

혁신조달 제도는 전략적 공공조달 정책의 일환으로 혁신제품 지정 및 우선구매 제도를 활용해 기업의 혁신역량 향상과 공공부문의 사회문제 해결능력 향상을 동시에 추구하는 정책으로 도입됐다. 혁신제품에 대한 시범구매 사업은 2019년에 처음 도입됐으며 2020년부터 정부 부처의 혁신제품 지정·발굴 체계가 확립된 후 혁신제품 우선구매제도가 본격적으로 실시됐다. 이에 본 연구는 혁신조달 제도가 본격적으로 시행된 이후 해당 제도의 기업지원 효과에 초점을 맞춰 정량적 분석을 진행했다. 이를 위해 2017년에서 2021년까지의 기업 재무제표 및 고용 자료를 이용했으며, 분석방법으로 성향점수매칭(PSM) 및 이중차분(DID) 방법을 활용했다. 본 연구를 통해 혁신조달 제도가 기업성장과 고용증대에 기여했으며 추가적인 공공 및 민간판로 개척 효과를 창출했음을 확인할 수 있었다. 한편 혁신조달 참여기업이 제품지정 종료 이후에도 자생성을 갖추기 위해서는 혁신제품 지정기업과 기존의 중소기업 지원정책을 적극 매칭하는 등 혁신조달 제도를 고도화할 필요가 있다.

PURPOSES : The primary objective of this study is to analyze the relationship between the factors that affect traffic incident duration in the mainline, tunnel, and ramp segments of an expressway. In addition, this study derived the most suitable statistical prediction model based on various incident duration distributions. METHODS : South Korean expressway crash data for 11 years, from 2011 to 2021, were analyzed. The incident durations on the mainline, tunnel, and ramp segments were selected using the accelerated failure time model, which is a parametric survival analysis approach. RESULTS : The mainline segment showed that the incident duration increased during accidents, including guard pipe collisions, multivehicle collisions, and snowfall. In particular, collisions in a tunnel with shoulder facilities increase the incident duration, while decreasing the time in the ramp segment. CONCLUSIONS : The incident duration model for each segment type yielded the most accurate results when applying a log-logistic distribution.

본 연구는 서울교육청 교육연구정보원의 「서울교육종단연구(SELS)」에 서 수집된 자료를 활용하여, 고등학생 3학년인 9차(2018년) 자료에서 학 생 2,793명을 연구 대상자로 정하였다. 청소년의 학교만족도와 관련한 예측요인을 확인하기 위해 SPSS 26.0을 사용하여 의사결정나무모형 분 석을 실시하였다. 연구결과를 살펴보면, 첫째, 청소년의 학교만족도의 분 류에서 개인적인 요인으로는 성별, 자아개념, 자기평가, 사회적 관계 요 인으로 보호자, 학교교사, 학교 특성/문화 요인으로는 학교에 대한 평가, 학교풍토가 유의한 변인으로 확인되었다. 둘째, 학교만족도 분류에 영향 을 주는 변인들 중에서는 학교에 대한 평가가 가장 영향력을 가진 변인 으로 나타났다. 셋째, 학교교사 수치가 높은 집단에서는 학교풍토, 자아 개념이 분류의 중요한 의미 있는 변인이었고, 학교교사 수치가 낮은 집 단에서는 자기평가, 학교풍토, 학교에 대한 평가가 영향력 있는 변인이었 다. 넷째, 학교에 대한 평가 수준 및 학교풍토가 바람직하고 좋으면 학교 만족도가 긍정적으로 상승하는 것으로 확인되었다. 본 연구결과는 청소 년의 학교만족도 증진을 위한 방안 모색, 교육정책 수립 및 프로그램 운 영에 도움이 될 것으로 사료된다.

본 연구는 한국노동패널 자료를 사용하여 선천적 직업적성이 직업만족도에 미치는 영향을 실증분석하였다. 분석을 위해서는 선천적 직업적성을 파악하는 것이 관건인데, 서양의 적성검사 기법은 한계가 있어서 동양사회에서 오랫동 안 실생활에 활용하고 있는 사주분석 기법을 적용하여 선천적 직업적성을 도 출하였다. 실증분석 결과, 첫째, 선천적 직업적성과 실제로 종사하고 있는 직업 유형이 일치한 사람의 직업만족도는 그렇지 않은 사람의 직업만족도보다 높았 다. 둘째, 선천적 직업적성과 종사하고 있는 직업유형과 일치한 사람은 그렇지 않은 사람보다 더 오랫동안 근무하며, 근속기간이 길수록 직업만족도는 높았 다. 셋째, 선천적 직업적성이 직장형이면 임금근로자가 될 가능성이 높았고, 선 천적 직업적성이 사업형이면 비임금근로자가 될 가능성이 높았다. 넷째, 경쟁심리가 강한 사람의 직업만족도는 경쟁 심리가 강하지 않은 사람의 직업만족 도보다 낮았다. 이러한 실증분석 결과는 선천적 직업적성이 직업만족도에 지 대한 영향을 미치고 있음을 입증한다. 직무만족은 삶의 만족과 긍정적인 관계 에 있다. 직무만족이 높을수록 삶의 만족 또한 높아지기 때문에 개인의 삶의 만족을 높이기 위해서는 자신의 선천적 직업적성을 정확히 이해하고, 선천적 직업적성에 맞는 직업유형을 선택하는 것이 무엇보다 중요하다.

This study examines the demand system of shrimp imported from top four countries and domestically produced by using AIDS (Almost Ideal Demand System) model. Top four import countries are Vietnam, Ecuador, China, and Malaysia based on the value of imports in 2021. As results of the analysis, the demand system of shrimp turn out to be below. First, the relationship of domestic shrimp and imported shrimp (Ecuadorian and Vietnamese) is identified as complements or substitutes depending on whether the income effect is considered. This result implies that imported shrimp supplements domestic supply against excess demand while homogeneous shrimp products competes with domestic shrimp in fish market. Second, the relationship among imported shrimps turned out to be both substitutes and complements. Especially, the Vietnamese shrimp is complementary with Chinese and Malaysian shrimp, but substitutes of Ecuadorian. It is assumed that adjoining Asian countries shares similar shrimp species and processing system which differentiates from Ecuadorian. Finally, the study included quarter as dummy variable and GDP as instrumental variable of expenditure in the model. The result confirmed that domestic shrimp is highly on demand during the main production season while imported shrimp is mainly demanded during the rest of the season.

The Severe Disaster Punishment Act had recently been established in order to promote safety and health (OSH) management system for severe accident prevention. OSH management system is primarily designed based on risk assessments; however, companies in industries have been experiencing difficulties in hazard identification and selecting proper measures for risk assessments and accident prevention. This study intended to introduce an accident analysis method based on epidemiological model in finding hazard and preventive measures. The accident analysis method employed in this study was proposed by the U.S. Department of Energy. To demonstrate the effectiveness of the accident analysis method, this study applied it to two accident cases occurred in construction and manufacturing industries. The application process and results of this study can be utilized in improving OSH management system and preventing severe accidents.

PURPOSES : This study aims to conduct a sensitivity analysis to determine the major factors affecting traffic accidents involving elderly pedestrians. METHODS : In this study, a regression tree model was built based on a non-parametric statistical model using data on traffic accidents involving elderly pedestrians. Using this model, we analyzed the degree of change in the probability of pedestrian fatalities. RESULTS : Results of the model analysis show that the first major factor combination affecting traffic accidents involving elderly pedestrians is speeding, night time, and road markers. The second combination is night time and arterial roads (national and local highways). The last combination that may lead to such accidents is heavy vehicles and federally funded local highways. CONCLUSIONS : Preventive measures, such as speed control, proper lighting, median strips, designation of pedestrian protection zones, and guidance of detours, are necessary to manage high-risk combinations causing accidents of the elderly.

Data commentary is an important text type in research articles; however, its discourse model is often challenging to access because it is embedded in the upper genres such as textbook, weather forecast, and journal article. This study aims to establish a discourse model of data commentary, with a focus on academic research papers in Economics and Business administration journals. To accomplish this, this study employs Move analysis and SF-MDA(Systemic Functional-Multimodal Discourse Analysis) to investigate the moves of data commentaries and the metafunctional meanings of each step. The results indicate that the data commentary discourse model consists of three moves: (1) summarizing the topic and methodology, (2) representing figure and numbers, and (3) analyzing and commenting on results. Additionally, 22 steps are identified for each move that creates metafunctional meaning: ideational, interpersonal, and textual.

There has been growing attention on the well-being of people with disabilities. The purpose of this study was twofold: (1) to investigate the associations between individuals’ socio-demographic and psychological characteristics and clothing expenditure, and (2) to examine the moderated mediation effect of self-efficacy and acceptance of disability on the association between dependency on others and happiness among people with visual impairment. This study was based on secondary analysis of data from the second wave of the 6th Panel Survey of Employment for the Disabled collected by the Employment Development Institute. The results of this study showed that average monthly expenditure on clothing was positively associated with self-efficacy, happiness, and acceptance of disability, while being negatively associated with dependency on others. The results also confirmed that self-efficacy mediated the association between dependency on others and happiness. A conditional direct effect of dependency on others on happiness was found, in which negative associations were significant among people with visual impairment who had low and mean levels of acceptance of disability (but not high levels). In addition, there was a significant conditional indirect effect, in which the indirect and negative effect of dependency on others on happiness via self-efficacy was significant for those with low and average levels of acceptance of disability. These findings support the importance of enhancing the independence and acceptance of disability among people with visual impairment, which ultimately contributes to their happiness.

In a group-testing method, instead of testing a sample, for example, blood individually, a batch of samples are pooled and tested simultaneously. If the pooled test is positive (or defective), each sample is tested individually. However, if negative (or good), the test is terminated at one pooled test because all samples in the batch are negative. This paper considers a queueing system with a two-stage group-testing policy. Samples arrive at the system according to a Poisson process. The system has a single server which starts a two-stage group test in a batch whenever the number of samples in the system reaches exactly a predetermined size. In the first stage, samples are pooled and tested simultaneously. If the pooled test is negative, the test is terminated. However, if positive, the samples are divided into two equally sized subgroups and each subgroup is applied to a group test in the second stage, respectively. The server performs pooled tests and individual tests sequentially. The testing time of a sample and a batch follow general distributions, respectively. In this paper, we derive the steady-state probability generating function of the system size at an arbitrary time, applying a bulk queuing model. In addition, we present queuing performance metrics such as the offered load, output rate, allowable input rate, and mean waiting time. In numerical examples with various prevalence rates, we show that the second-stage group-testing system can be more efficient than a one-stage group-testing system or an individual-testing system in terms of the allowable input rates and the waiting time. The two-stage group-testing system considered in this paper is very simple, so it is expected to be applicable in the field of COVID-19.

PURPOSES : To efficiently manage pavements, a systematic pavement management system must be established based on regional characteristics. Suppose that the future conditions of a pavement section can be predicted based on data obtained at present. In this case, a more reasonable road maintenance strategy should be established. Hence, a prediction model of the annual surface distress (SD) change for national highway pavements in Gangwon-do, Korea is developed based on influencing factors. METHODS : To develop the model, pavement performance data and influencing factors were obtained. Exploratory data analysis was performed to analyze the data acquired, and the results show that the data were preprocessed. The variables used for model development were selected via correlation analysis, where variables such as surface distress, international roughness index, daily temperature range, and heat wave days were used. Best subset regression was performed, where the candidate model was selected from all possible subsets based on certain criteria. The final model was selected based on an algorithm developed for rational model selection. The sensitivity of the annual SD change was analyzed based on the variables of the final model. RESULTS : The result of the sensitivity analysis shows that the annual SD change is affected by the variables in the following order: surface distress ˃ heat wave days ˃ daily temperature range ˃ international roughness index. CONCLUSIONS : An annual SD change prediction model is developed by considering the present performance, traffic volume, and climatic conditions. The model can facilitate the establishment of a reasonable road maintenance strategy. The prediction accuracy can be improved by obtaining additional data, such as the construction quality, material properties, and pavement thickness.

The sewer capacity design have been based on the Huff model or the rational equation in South Korea and often failed to determine optimal capacity, resulting in frequent urban flooding or over-sizing. A time distribution of rainfall (i.e., Huff or ABM method) could be used instead of a rainfall hyetograph obtained from statistical analysis of previous rainfalls. In this study, the Huff method and the ABM method, which predict the time distribution of rain intensity, which are widely used to calculate sewage pipe drainage capacity using the SWMM, were compared with the standard rainfall intensity hyetograph of Seoul. If the rainfall duration was 30 minutes to 180 minutes, the rainfall intensity value calculated by the Huff model tended to be less than the rainfall intensity value of the standard rainfall intensity in the initial 5-10 minutes. As a result, more than 10% to 30% of under-design would be made. In addition, the rainfall intensity value calculated by the Huff model from the section excluding the initial 5-10 minutes of rainfall to the rainfall duration was calculated larger than the value using the standard rainfall intensity equation, which would result in an over-design of 10% to 30%. In the case of a relatively long rainfall duration of 360 minutes (6 hours) to 1,440 minutes (24 hours), it showed an lower rainfall intensity of 60 to 90% in the early stages of rainfall, but the problem of under-design had been solved as the rainfall duration time had elapsed. On the other hand, in the alternating block method (ABM) method, it was found that the rainfall intensity at the entire period at each assumed rainfall duration accurately matched the standard rainfall intensity hyetograph of Seoul.

목적: Gullstrand 모형안에서 색수차를 이론적으로 산출하였으며, 3D 시뮬레이션을 통해 확인하였고, 두 결과를 서로 비교하고자 했다. 방법 : 이론적 색수차는 Mathematica 12.3.1(Wolfram Research, USA)를 통해 산출하였으며, Gullstrand 모형안의 3D 구현은 Ansys SPEOS Ver. 2012(ANSYS Inc, USA)를 이용하였고, 가시광선 영역의 파장에서 노 란색( =586.700  ), 파란색( =486.100  ) 및 빨간색( =656.300  ) 광선의 종색수차와 횡색수차를 측정하였다. 결과 : 이론적 및 모의적인 방법 모두에서 입사광선의 높이가 증가하고, 파장이 짧아질수록 모형안을 통과한 광선의 초점거리는 감소하는 것으로 나타났다. 모형안의 중심부에서 주변부로 갈수록 종색수차는 미세하게 감소하 였으나, 횡색수차는 증가하는 것으로 나타났다. 결론 : 이론적 및 모의적인 방법으로 확인한 색수차는 거의 유사한 추의를 보였으나, 매우 미세한 차이가 발견 되었다. 색수차의 다양한 특성을 파악하기 위해서는 모형안에서 조절이나 굴절이상과 같은 조건의 정밀한 모델링 이 반영된 후속 연구가 필요할 것으로 판단된다.