• Journal of Korean Institute of Industrial Engineers
• /
• v.27 no.3
• /
• pp.281-288
• /
• 2001

We consider in this article a multi-objective part-machine grouping problem in which parts have alternative process plans and expected annual demand of each part is known. This problem is characterized as optimally determining part sets and corresponding machine cells such that total sum of distance (or dissimilarity) between parts and total sum of load differences between machines are simultaneously minimized. Two heuristic algorithms are proposed, and examples are given to compare the performance of the algorithms.

• Journal of Industrial Convergence
• /
• v.18 no.4
• /
• pp.9-14
• /
• 2020

The purpose of this study is to analyze the relationship between high school teachers' grit and stress coping strategies and to understand differences in stress coping strategies by cluster types of grit. 226 in-service teachers participated in the survey who took the professional development program in the national educational training institute. Results are as follows. First, perseverance of effort in grit was the positively independent variable toward task-oriented and emotion-oriented strategies. The avoidance-oriented strategy was negatively influenced by consistency of interest in grit. Also, the clusters of high grit and high perseverance of effort in grit showed higher means in task-oriented and emotion-oriented strategies than the cluster of low grit. Finally, researchers discussed the importance of strengthening high school teachers' grit for them to cope with job stress effectively.

• Journal of Digital Contents Society
• /
• v.18 no.7
• /
• pp.1249-1257
• /
• 2017

Due to the 4th industrial revolution and an aged society, many studies are being conducted to apply virtual reality to medical field. Research on dementia is especially active. This paper proposes virtual reality based on cognitive rehabilitation contents using image recognition and clustering method to improve cognitive and physical disabilities caused by dementia. Unlike the existing cognitive rehabilitation system, this paper uses travel photos that reflect the memories of the subjects to be treated. In order to generate automated cognitive rehabilitation contents, we extract face information, food pictures, place information, and time information from photographs, and normalization is performed for clustering. And we present scenarios that can be used as cognitive rehabilitation contents using travel photos in virtual reality space.

• Journal of the Korea Convergence Society
• /
• v.10 no.11
• /
• pp.159-164
• /
• 2019

Recent developments in ICT technology have increased interest in the care and health of pets such as dogs and cats. In this paper, cluster analysis was performed based on the component data of pet food to be used in various fields of the pet industry. For cluster analysis, the similarity was analyzed by analyzing the correlation between components of 300 dogs and cats in the market. In this paper, clustering techniques such as Hierarchical, K-Means, Partitioning around medoids (PAM), Density-based, Mean-Shift are clustered and analyzed. We also propose a personalized recommendation system for pets. The results of this paper can be used for personalized services such as feed recommendation system for pets.

• Journal of the Korea Convergence Society
• /
• v.11 no.9
• /
• pp.219-227
• /
• 2020

Smart Factory is one of the fastest developing and changing fourth industrial revolution fields. In particular, the degree of introduction and maturity level in the smart factory is an important part. In this paper, a cluster analysis of companies introduced smart factory was performed based on a new maturity assessment model. The 68% of 193 companies surveyed were at the basic level, with only 21% being the middle one. Most SMEs cited lack of funds as the main reason for not entering the middle one. As a result of the cluster analysis, it was found that all clusters had similar patterns but grouped into one of three levels of high, middle, and low depending on maturity level of smart factory operation, and process domain had the highest maturity and data domain was lowest among the 6 domains. Through this, analysis of more specific and quantified maturity levels can be performed using 6-domain smart factory maturity evaluation model.

• The Journal of Korean Association of Computer Education
• /
• v.22 no.5
• /
• pp.51-65
• /
• 2019

This study aims to provide educational implications for more strategic online software education by the types of online learning according to learners' self-regulated learning characteristics in the online software education environment and examining the characteristics of each type. For this, variables related to self-regulated learning characteristic were extracted from the log data of 809 students participating in the online software learning program of K University, and then analyzed using hierarchical cluster analysis. Based on hierarchical cluster analysis learner clusters according to the characteristics of self-regulated learning were derived and the differences between learners' learning characteristics and learning results according to cluster types were examined. As a result, the types of self-regulated learning of online software learners were classified as 'high level self-regulated learning type (group 1)', 'medium level self-regulated learning type (group 2)', and 'low level self-regulated learning type (group 3)'. The achievement level was found to be highest in 'high-level self-regulated learning type (group 1)' and 'low-level self-regulated learning type (group 3)' was the lowest. Based on these results, the implications for effective online software education were suggested.

• Ecology and Resilient Infrastructure
• /
• v.10 no.4
• /
• pp.237-249
• /
• 2023

This study was carried to establish a new landscape-oriented gardening model based on climate, vegetation, and forest landscape characteristics. In addition, innovative forest garden models were suggested through an integrated approach to the ecological characteristics of forest vegetation communities and existing garden planting types. For the study, the key landscape elements that make up the main forest vegetation community were identified. And the vertical layers and horizontal distribution patterns of the community structure were typified by diagnostic species and their growth forms & habits such as dominant species, character species, and differential species, and degree of dominance-sociability. Based on this, a standardized vegetation structure and formation was developed by stratifying the landscape into main features, minor features, and detailed features according to visual dominant elements. Also, the applicability of the forest garden model was examined by applying the concept of borrowing landscape to representative deciduous broadleaf forests in the temperate northern region of Korea. Additionally, an integrated forest garden models based on the conceptual definition and typology of forest gardens, and a strategic approach to forest vegetation were proposed

• Journal of Life Science
• /
• v.33 no.7
• /
• pp.565-573
• /
• 2023

In light of the complex interactions between the host animal and its resident gut microbiomes, studies of these microbial communities as a means to improve cattle production are important. This study was conducted to analyze the intestinal microorganisms of Holstein (HT) and Jersey (JS), raised in Korea and to clarify the differences in microbial structures according to cattle species through next-generation sequencing. The alpha-diversity analysis revealed that most species richness and diversity indices were significantly higher in JS than in HT whereas phylogenetic diversity, which is the sum of taxonomic distances, is not significant. Microbial composition analysis showed that the intestinal microbial community structure of the two groups differed. In the both groups, a significant correlation was observed among the distribution of several microbes at the family level. In particular, a highly significant correlation (p<0.0001) among a variety of microbial distributions was found in JS. Beta-diversity analyis was to performed to statistically verify whether a difference exists in the intestinal microbial community structure of the two groups. Principal coordinate analysis and unweighted pair group method with arithmetic mean (UPGMA) clustering analysis showed separation between the HT and JS clusters. Meanwhile, permutational multivariate analysis of variance (PERMANOVA) revealed that their microbial structures are significantly different (p<0.0001). LEfSe biomarker analysis was performed to discover the differenc microbial features between the two groups. We found that several microbes, such as Firmicutes, Bacilli, Moraxellaceae and Pseudomonadales account for most of the difference in intestinal microbial community structure between the two groups.

• Journal of Life Science
• /
• v.33 no.6
• /
• pp.481-489
• /
• 2023

The taste and quality of soy sauce, a fermented liquid condiment, is greatly influenced by microbial metabolism during fermentation. To investigate the microbiological characteristics of ganjang during the initial fermentation process, we prepared meju (fermented soybean) blocks fermented with starter cultures and solar salts and analyzed the microbial community quantitively using 16S rRNA gene profiling from ganjang that had been fermented over a five-week period. The ganjang samples were collected and analyzed after soaking for week one (1W), three (3W), and five (5W) weeks. We found that Halomonadaceae was significantly higher in the 1W group (89.83%) than the 3W and 5W groups (14.46%, and 13.78%, respectively). At a species level, Chromohalobacter beijerinckii and Chromohalobacter canadensis were the dominant species in the 1W group but several taxa such as Bacillus subtilis, Pediococcus acidilactici, and Enterococcus faecalis were more abundant in the 3W and 5W groups. Pearson correlation analysis of the relative abundance of the bacteria showed a negative correlation between Chromohalobacter and two bacterial genera Bacillus and Enterococcus. Beta-diversity showed a statistical distinction between the 1W and the 3W and 5W groups, while no significance was evident between the 3W and 5W groups. Linear discriminant effect size analysis was used to identify biomarkers and significant differences in the relative abundance of several halophilic bacteria, Bacillus sp. and lactic acid bacteria at 1W, 3W, and 5W, recpectively, which indicates the important role of the bacterial community at these time points.

• Journal of the Korea Society for Simulation
• /
• v.28 no.4
• /
• pp.21-32
• /
• 2019

Inspired by the social behavior models of a bird flock or fish school, particle swarm optimization (PSO) is a popular metaheuristic optimization algorithm and has been widely used from solving a complex optimization problem to learning a artificial neural network. However, PSO is difficult to apply to many real-life optimization problems involving stochastic noise, since it is originated in a deterministic environment. To resolve this problem, this paper incorporates a resampling method called the uncertainty evaluation (UE) method into PSO. The UE method allows the particles to converge on the accurate optimal solution quickly in a noisy environment by selecting the particles' global best position correctly, one of the significant factors in the performance of PSO. The results of comparative experiments on several benchmark problems demonstrated the improved performance of the propose algorithm compared to the existing studies. In addition, the results of the case study emphasize the necessity of this work. The proposed algorithm is expected to be effectively applied to optimize complex systems through digital twins in the fourth industrial revolution.