• Journal of the Korea Society for Simulation
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• v.33 no.1
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• pp.1-17
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• 2024

Forest management is known to beneficially influence stand structure and wood production, yet quantitative understanding as well as an illustrative depiction of the effects of different management approaches on tree growth and stand dynamics are still scarce. Long-term management of beech forests must balance public interests with ecological aspects. Efficient forest management requires the reliable prediction of tree growth change. We aimed to develop a novel hybrid simulation approach, which realistically simulates short- as well as long-term effects of different forest management regimes commonly applied, but not limited, to German low mountain ranges, including near-natural forest management based on single-tree selection harvesting. The model basically consists of three modules for (a) natural seedling regeneration, (b) mortality adjustment, and (c) tree growth simulation. In our approach, an existing validated growth model was used to calculate single year tree growth, and expanded on by including in a newly developed simulation process using calibrated modules based on practical experience in forest management and advice from the local forest. We included the following different beech forest-management scenarios that are representative for German low mountain ranges to our simulation tool: (1) plantation, (2) continuous cover forestry, and (3) reserved forest. The simulation results show a robust consistency with expert knowledge as well as a great comparability with mid-term monitoring data, indicating a strong model performance. We successfully developed a hybrid simulation that realistically reflects different management strategies and tree growth in low mountain range. This study represents a basis for a new model calibration method, which has translational potential for further studies to develop reliable tailor-made models adjusted to local situations in beech forest management.

• Journal of the Society of Disaster Information
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• v.20 no.1
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• pp.20-31
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• 2024

Purpose: Research and development of high-strength concrete enables high-rise buildings and reduces the self-weight of the structure by reducing the cross-section, thereby reducing the thickness of beams and slabs to build more floors. A large effective space can be secured and the amount of reinforcement and concrete used to designate the base surface can be reduced. Method: In terms of field construction and quality, the effect of reducing the occurrence of drying shrinkage can be confirmed by studying the combination of low water bonding ratio and minimizing bleeding on the concrete surface. Result: The ease of site construction was confirmed due to the high self-charging property due to the increased fluidity by using high-performance water reducing agents, and the advantage of shortening the time to remove the formwork by expressing the early strength of concrete was confirmed. These experimental results show that the field application of ultra-high-strength concrete with a design standard strength of 100 MPa or higher can be expanded in high-rise buildings. Through this study, we experimented and evaluated whether ultra-high-strength concrete with a strength of 130 MPa or higher, considering the applicability of high-rise buildings with more than 120 floors in Korea, could be applied in the field. Conclusion: This study found the optimal mixing ratio studied by various methods of indoor basic experiments to confirm the applicability of ultra-high strength, produced 130MPa ultra-high strength concrete at a ready-mixed concrete factory similar to the real size, and tested the applicability of concrete to the fluidity and strength expression and hydration heat.

• Information Systems Review
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• v.25 no.2
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• pp.181-203
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• 2023

With the fierce competition of companies for the attraction of outstanding individuals, job satisfaction of employees has been of importance. In this circumstance, many companies try to invest in job satisfaction improvement by finding employees' everyday experiences and difficulties. However, due to a lack of understanding of the employee experience, their investments are not paying off. This study examined the relationship between employee experience and job satisfaction using employee reviews and company ratings from Glassdoor, one of the largest employee communities worldwide. We use text mining techniques such as K-means clustering and LDA topic-based sentiment analysis to extract key experience factors by job level, and DistilBERT sentiment analysis to measure the sentiment score of each employee experience factor. The drawn employee experience factors and each sentiment score were analyzed quantitatively, and thereby relations between each employee experience factor and job satisfaction were analyzed. As a result, this study found that there is a significant difference between the workplace experiences of managers and general employees. In addition, employee experiences that affect job satisfaction also differed between positions, such as customer relationship and autonomy, which did not affect the satisfaction of managers. This study used text mining and quantitative modeling method based on theory of work adjustment so as to find and verify main factors of employee experience, and thus expanded research literature. In addition, the results of this study are applicable to the personnel management strategy for improving employees' job satisfaction, and are expected to improve corporate productivity ultimately.

• Korean Journal of Heritage: History & Science
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• v.57 no.3
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• pp.202-222
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• 2024

War is one of the most tragic and destructive incidents in human history, and it destroys precious cultural heritage. However, even amidst such devastation, certain cultural heritages convey messages of peace and human rights. This study aims to provide an in-depth interpretation of the significance of cultural heritage related to war. The research method involved an extensive review of theoretical discussions on war-related heritage. Based on this foundation, 18 cases of war heritage registered as UNESCO World Heritage Sites were selected. These cases were classified and analyzed into three categories: "physical traces of war and military fortresses," "memories of war and atrocities, and messages of peace," and "restoration and reconstruction of cities destroyed by war." The results of this study confirm that war heritage encompasses not only physical evidence of war but also multilayered and complex meanings such as the memories and traumas of war, scars and healing, and conflict and reconciliation. Based on these findings, the study proposes that war heritage should be reinterpreted and expanded to represent a "heritage of peace" and transcend its role of only including physical traces of war to embody the values of peace. This demands a shift in perception that confronts the painful memories of war while transforming them into assets for building peace. Furthermore, it urges the active exploration of ways to utilize war heritage for peaceful purposes. This study distinguishes itself from existing research by deepening the academic discourse on war-related heritage and providing a theoretical foundation for the registration of war-related heritage as World Heritage Sites.

• Journal of Christian Education in Korea
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• v.75
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• pp.103-125
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• 2023

This study aims to explore the direction and tasks of Christian unification education as peace education. To this end, after examining the historical trend of peace education and unification education in Korea, the tasks of peaceful unification education are reviewed. Peace education has expanded with the activation of peace movements and educational discourse starting from civil society, while unification education has been planned in accordance with the government's unification and North Korea policy and is moving toward the field of education practice. However, due to the nature of unification education that aspires for peace, the combination of the two fields has continued steadily, and research on peace unification education has been continuously conducted. The direction and tasks of Christian unification education as peace education were proposed based on the tasks of peace unification education derived through prior research analysis and the trend of the times in the two areas to carry out the research purpose. For the sustainability of peace on the Korean Peninsula, Christian unification education as a peace education should aim to foster peaceful citizens who take the lead in transitioning from a culture of violence to a culture of peace. To this end, first, it is necessary to seek the direction of Christian education for the dissolution of the antagonist image. Second, activities that guarantee learners' subjectivity and autonomy should be carried out away from the top-down method in teaching and learning. Third, a curriculum connected to daily life should be formed.

• Annals of Occupational and Environmental Medicine
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• v.34
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• pp.30.1-30.13
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• 2022

Background: Although working hours have decreased in Korea, they are still high compared to that of other countries. In Korea, cardiovascular and cerebrovascular diseases (CCVDs) related to overwork in Korea continually occur, and the social burden from overwork is estimated to be high. This study investigated the amendment of regulations affecting the approval rate of occupational CCVDs. Methods: The change in approval rate of occupational CCVDs and related regulations were investigated using the Act and public notice on the standards for recognition of occupational CCVDs and the yearbooks of the Ministry of Employment and Labor. The CCVD mortality was estimated using data on the number of deaths according to the cause of death, the number of employed people, and resident registration population aged 15-64 years. The cumulative mortality of CCVDs was estimated using the Kaplan-Meier method. Results: Since the establishment of the standards for recognition in Korea in 1982, the scope of occupational diseases has been expanded to include intracerebral hemorrhage, subarachnoid hemorrhage, cerebral infarction, myocardial infarction, and aortic dissection. In 2013, the concept of working hours was introduced in chronic overwork. The approval rate of occupational CCVDs was 44.7% in 2006, which decreased to 12.9% in 2011. After the improvement of related regulations, the approval rate increased to 41.3% in 2018. From 2000 to 2017, the CCVD mortality of both the unemployed and employed tended to decrease, and their cumulative CCVD mortalities were 549.3 and 319.7 per 100,000 people, respectively. Conclusions: CCVDs are recognized as occupational diseases in Korea. The amendments to the standards for recognition, the introduction of the Occupational Disease Adjudication Committee, the principle of presumption, and the reduction of working hours have changed the approval rate of occupational CCVDs. A strategic approach is needed to further reduce the incidence of CCVDs.

• The Journal of the Convergence on Culture Technology
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• v.10 no.5
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• pp.397-406
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• 2024

Today, in the field of contemporary fashion design, AI is being actively utilized as a new design tool, leading to a new paradigm of collaboration between designers and AI. This study is about a method for developing integrated fashion design through collaboration between human designers and AI. The purpose of this study is to analyze the visual and formative characteristics and changes of fashion design images generated using the AI generation program Midjourney, thereby expanding the understanding and utilization methods of AI image generation programs in fashion design development. The results of this study are as follows. First, Midjourney has the characteristic of relying more on the characteristics of the existing image used rather than the command when creating the image. It also creates new images by distributing and applying the design through an eclectic interaction between the costume and the image background. By excluding the names of fashion items from the commands, you can generate images that can give you more diverse ideas. Second, Midjourney initially expressed clothing colors using colors used in fashion schematics in color creation, and gradually expanded to various color series. Third, there is a kind of compromise between color and design when Midjourney creates an image, and accordingly, by specifying and limiting the image background and clothing colors, more diverse and advanced fashion design images can be created.

• Ocean and Polar Research
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• v.46 no.3
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• pp.131-142
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• 2024

Ocean change due to anthropogenic activities and climate change are causing a decline in coldwater fish species and emergence of subtropical fish species in Korean waters. Therefore, environmental change-dependent time-space distribution of fishery resources in Korea, which has a big fisheries industry, needs to be investigated. Environmental DNA (eDNA) metabarcoding is an environmentally noninvasive method for understanding the spatiotemporal distribution of marine organisms at high spatial resolution. The highly variable cytochrome oxidase-1 (CO1) gene is used in eDNA studies for species identification across diverse taxa. However, it exhibits genetic differences depending on geographical distribution. For improving the accuracy of eDNA research, the CO1 database should be expanded by incorporating sequence information for individuals inhabiting the Korean seas. Here, 106 biological samples from the Yellow Sea were identified morphologically and their nucleotide sequences were compared with those in the GenBank. Most sequences were 100% identical with those in the GenBank. In most samples, the morphological and molecular identification results were consistent, indicating the utility of CO1. However, some nucleotide sequences differed from those in the database. Amino acid sequences translated from nucleotide sequences with less than 97% similarity showed high similarity to the amino acid database, indicating intraspecies variation due to "silent mutations". These results highlight the need for a sequence database of fishery resources in Korean coastal waters to improve the reliability of eDNA studies using CO1. However, because of the same CO1 sequences in several species, genetic markers need to be developed and the database should be supplemented with more sequences for reliable high-resolution eDNA studies.

• Journal of the Ergonomics Society of Korea
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• v.35 no.4
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• pp.293-305
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• 2016

Objective: This study aims to measure cognitive load levels by analyzing the EEG of Koreans and foreigners, when they read a Korean text with care selected by level from the grammar and vocabulary aspects, and compare the cognitive load levels through quantitative values. The study results can be utilized as basic data for more scientific approach, when Korean texts or books are developed, and an evaluation method is built, when the foreigners encounter them for learning or an assignment. Background: Based on 2014, the number of the foreign students studying in Korea was 84,801, and they increase annually. Most of them are from Asian region, and they come to Korea to enter a university or a graduate school in Korea. Because those foreign students aim to learn within Universities in Korea, they receive Korean education from their preparation for study in Korea. To enter a university in Korea, they must acquire grade 4 or higher level in the Test of Proficiency in Korean (TOPIK), or they need to complete a certain educational program at each university's affiliated language institution. In such a program, the learners of the Korean language receive Korean education based on texts, except speaking domain, and the comprehension of texts can determine their academic achievements in studying after they enter their desired schools (Jeon, 2004). However, many foreigners, who finish a language course for the short-term, and need to start university study, cannot properly catch up with university classes requiring expertise with the vocabulary and grammar levels learned during the language course. Therefore, reading education, centered on a strategy to understand university textbooks regarded as top level reading texts to the foreigners, is necessary (Kim and Shin, 2015). This study carried out an experiment from a perspective that quantitative data on the readers of the main player of reading education and teaching materials need to be secured to back up the need for reading education for university study learners, and scientifically approach educational design. Namely, this study grasped the difficulty level of reading through the measurement of cognitive loads indicated in the reading activity of each text by dividing the difficulty of a teaching material (book) into eight levels, and the main player of reading into Koreans and foreigners. Method: To identify cognitive loads indicated upon reading Korean texts with care by Koreans and foreigners, this study recruited 16 participants (eight Koreans and eight foreigners). The foreigners were limited to the language course students studying the intermediate level Korean course at university-affiliated language institutions within Seoul Metropolitan Area. To identify cognitive load, as they read a text by level selected from the Korean books (difficulty: eight levels) published by King Sejong Institute (Sejonghakdang.org), the EEG sensor was attached to the frontal love (Fz) and occipital lobe (Oz). After the experiment, this study carried out a questionnaire survey to measure subjective evaluation, and identified the comprehension and difficulty on grammar and words. To find out the effects on schema that may affect text comprehension, this study controlled the Korean texts, and measured EEG and subjective satisfaction. Results: To identify brain's cognitive load, beta band was extracted. As a result, interactions (Fz: p =0.48; Oz: p =0.00) were revealed according to Koreans and foreigners, and difficulty of the text. The cognitive loads of Koreans, the readers whose mother tongue is Korean, were lower in reading Korean texts than those of the foreigners, and the foreigners' cognitive loads became higher gradually according to the difficulty of the texts. From the text four, which is intermediate level in difficulty, remarkable differences started to appear in comparison of the Koreans and foreigners in the beginner's level text. In the subjective evaluation, interactions were revealed according to the Koreans and foreigners and text difficulty (p =0.00), and satisfaction was lower, as the difficulty of the text became higher. Conclusion: When there was background knowledge in reading, namely schema was formed, the comprehension and satisfaction of the texts were higher, although higher levels of vocabulary and grammar were included in the texts than those of the readers. In the case of a text in which the difficulty of grammar was felt high in the subjective evaluation, foreigners' cognitive loads were also high, which shows the result of the loads' going up higher in proportion to the increase of difficulty. This means that the grammar factor functions as a stress factor to the foreigners' reading comprehension. Application: This study quantitatively evaluated the cognitive loads of Koreans and foreigners through EEG, based on readers and the text difficulty, when they read Korean texts. The results of this study can be used for making Korean teaching materials or Korean education content and topic selection for foreigners. If research scope is expanded to reading process using an eye-tracker, the reading education program and evaluation method for foreigners can be developed on the basis of quantitative values.

• Journal of Intelligence and Information Systems
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• v.24 no.2
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• pp.21-35
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• 2018

Since the introduction of MP3 players, CD recordings have gradually been vanishing, and the music consuming environment of music users is shifting to mobile devices. The introduction of smart devices has increased the utilization of music through music playback, mass storage, and search functions that are integrated into smartphones and tablets. At the time of initial MP3 player supply, the bitrate of the compressed music contents generally was 128 Kbps. However, as increasing of the demand for high quality music, sound quality of 384 Kbps appeared. Recently, music content of FLAC (Free License Audio Codec) format using lossless compression method is becoming popular. The download service of many music sites in Korea has classified by unlimited download with technical protection and limited download without technical protection. Digital Rights Management (DRM) technology is used as a technical protection measure for unlimited download, but it can only be used with authenticated devices that have DRM installed. Even if music purchased by the user, it cannot be used by other devices. On the contrary, in the case of music that is limited in quantity but not technically protected, there is no way to enforce anyone who distributes it, and in the case of high quality music such as FLAC, the loss is greater. In this paper, the author proposes an audio watermarking technology for copyright protection of high quality stereo music. Two kinds of information, "Copyright" and "Copy_free", are generated by using the turbo code. The two watermarks are composed of 9 bytes (72 bits). If turbo code is applied for error correction, the amount of information to be inserted as 222 bits increases. The 222-bit watermark was expanded to 1024 bits to be robust against additional errors and finally used as a watermark to insert into stereo music. Turbo code is a way to recover raw data if the damaged amount is less than 15% even if part of the code is damaged due to attack of watermarked content. It can be extended to 1024 bits or it can find 222 bits from some damaged contents by increasing the probability, the watermark itself has made it more resistant to attack. The proposed algorithm uses quantization in DCT so that watermark can be detected efficiently and SNR can be improved when stereo music is converted into mono. As a result, on average SNR exceeded 40dB, resulting in sound quality improvements of over 10dB over traditional quantization methods. This is a very significant result because it means relatively 10 times improvement in sound quality. In addition, the sample length required for extracting the watermark can be extracted sufficiently if the length is shorter than 1 second, and the watermark can be completely extracted from music samples of less than one second in all of the MP3 compression having a bit rate of 128 Kbps. The conventional quantization method can extract the watermark with a length of only 1/10 compared to the case where the sampling of the 10-second length largely fails to extract the watermark. In this study, since the length of the watermark embedded into music is 72 bits, it provides sufficient capacity to embed necessary information for music. It is enough bits to identify the music distributed all over the world. 272 can identify $4*10^{21}$, so it can be used as an identifier and it can be used for copyright protection of high quality music service. The proposed algorithm can be used not only for high quality audio but also for development of watermarking algorithm in multimedia such as UHD (Ultra High Definition) TV and high-resolution image. In addition, with the development of digital devices, users are demanding high quality music in the music industry, and artificial intelligence assistant is coming along with high quality music and streaming service. The results of this study can be used to protect the rights of copyright holders in these industries.