• Title/Summary/Keyword: 산업기술개발

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Particle Size Characteristics with the Specification of Yeongdong Illite Powder Products (영동 일라이트 분말 제품의 규격에 따른 입도 특성)

  • EunJi Baek;Yu Na Lee;Eun Jeong Kim;Youngseuk Keehm;Hyun Na Kim
    • Korean Journal of Mineralogy and Petrology
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    • v.36 no.4
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    • pp.345-353
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    • 2023
  • This study aimed to investigate the differences in the commercial powder products of the Yeongdong illite based on sales specifications, specifically examining the mineralogical composition, particle size, and chemical composition according to mesh size. The goal was to understand the characteristics of illite powder products and utilize them as a mineralogical database for exploring various applications. Commercial illite powder samples obtained from two mines were subjected to various experiments, including X-ray diffraction (XRD) analysis, laser diffraction particle size analysis, and scanning electron microscopy analysis, X-ray fluorescence analysis. The XRD analysis revealed that the illite powder products from the two mines mainly consisted of illite/muscovite, quartz, and feldspar, indicating similar constituent minerals matching with those of ores for each mine. Laser diffraction particle size analysis indicated the difference in particle size distribution depending on the product specifications, with particle size uniformity tending to increase with increasing mesh sizes. Scanning electron microscopy analysis showed variations in particle shape and size based on specifications. The size of illite particles did not vary significantly with product specifications, with noticeable changes observed mainly in the particle sizes of quartz and feldspar. Furthermore, although there were some differences in chemical composition among the samples from different mines, no significant variations were observed according to specifications. Based on these results, when considering the application of commercial illite powder, it is essential to carefully select it with the consideration of its specifications to account for characteristic variations. The findings of this study present support the great potential of various application fields of commercial illite powder, contributing to industrial utilization and the development of new technologies.

Current Research Trends in Entrepreneurship Based on Topic Modeling and Keyword Co-occurrence Analysis: 2002~2021 (토픽모델링과 동시출현단어 분석을 이용한 기업가정신에 대한 연구동향 분석: 2002~2021)

  • Jang, Sung Hee
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.17 no.3
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    • pp.245-256
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    • 2022
  • The purpose of this study is to provide comprehensive insights on the current research trends in entrepreneurship based on topic modeling and keyword co-occurrence analysis. This study queried Web of Science database with 'entrepreneurship' and collected 14,953 research articles between 2002 and 2021. The study used R program for topic modeling and VOSviewer program for keyword co-occurrence analysis. The results of this study are as follows. First, as a result of keyword co-occurrence analysis, 5 clusters divided: entrepreneurship and innovation cluster, entrepreneurship education cluster, social entrepreneurship and sustainability cluster, enterprise performance cluster, and knowledge and technology transfer cluster. Second, as a result of the topic modeling analysis, 12 topics found: start-up environment and economic development, international entrepreneurship, venture capital, government policy and support, social entrepreneurship, management-related issues, regional city planning and development, entrepreneurship research, and entrepreneurial intention. Finally, the study identified two hot topics(venture capital and entrepreneurship intention) and a cold topic(international entrepreneurship). The results of this study are useful to understand current research trends in entrepreneurship research and provide insights into research of entrepreneurship.

Design and fAbrication of Triple Band WLAN Antenna Applicable to Wi-Fi 6E Band with DGS (DGS를 갖는 Wi-Fi 6E 대역을 위한 삼중대역 WLAN 안테나 설계 및 제작)

  • Sang-Wook Park;Gi-Young Byun;Joong-Han Yoon
    • The Journal of the Korea institute of electronic communication sciences
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    • v.19 no.2
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    • pp.345-354
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    • 2024
  • In this paper, we propose a triple band WLAN antenna for Wi-Fi 6E band with DGS. The proposed antenna has the characteristics required frequency band and bandwidth by considering the interconnection of two strip lines and three areas on the ground place. The total substrate size is 31 mm (W) × 50 mm (L), thickness (h) 1.6 mm, and the dielectric constant is 4.4, which is made of 22 mm (W6 + W4 + W5) × 43mm (L1 + L2 + L3 + L5) antenna size on the FR-4 substrate. From the fabrication and measurement results, bandwidths of 340 MHz (1.465 to 1.805 GHz) for 900 MHz band, 480 MHz (2.155 to 2.635 GHz) for 2.4 GHz band and 1950 MHz (4.975 to 6.925 GHz) for 5.0/6.0 GHz band were obtained on the basis of -10 dB. Also, gain and radiation pattern characteristics are measured and shown in the frequency triple band as required.

Physicochemical characteristics of hot-water leachate prepared from persimmon leaf dried after steaming or freezing treatment (스팀 및 동결 전처리가 건조 감잎 열수추출물의 이화학적 특성에 미치는 영향)

  • Hun-Sik Chung;Kwang-Sup Youn;Jong-Kuk Kim
    • Food Science and Preservation
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    • v.30 no.6
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    • pp.983-990
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    • 2023
  • This study was conducted to develop a preservation technology that can induce changes in physicochemical properties to effectively utilize of persimmon leaves. The application effects of steaming or freezing technique were investigated. Astringent persimmon leaves were steam-blanched (100℃, 30 sec) or frozen (-20℃, 15 d), followed by hot-air drying (50℃). The physicochemical properties of the extract obtained by hot-water leaching from the dried leaves were compared. The extract of leaves dried without pretreatment was used as a control. L* value was higher in steamed than in control and frozen. a* value was highest in the control. The browning index was higher in the frozen and lower in the steamed than in the control. Soluble solids were the highest in the steamed and the lowest in the frozen. Sucrose content was relatively high in the steamed, and the glucose and fructose contents were relatively high in the frozen. Total polyphenol content and DPPH radical scavenging activity were higher in steamed and lower in frozen than in control. Thus, it was confirmed that steam or freeze pretreatment after harvesting persimmon leaves affects the extraction yield, color, antioxidant capacity and component changes of dried persimmon leaves. Unlike steaming, freezing pretreatment showed the effect of promoting decomposition and browning reactions, and it is considered useful when such an effect is needed.

A Study on the Calculation of Optimal Compensation Capacity of Reactive Power for Grid Connection of Offshore Wind Farms (해상풍력단지 전력계통 연계를 위한 무효전력 최적 보상용량 계산에 관한 연구)

  • Seong-Min Han;Joo-Hyuk Park;Chang-Hyun Hwang;Chae-Joo Moon
    • The Journal of the Korea institute of electronic communication sciences
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    • v.19 no.1
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    • pp.65-76
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    • 2024
  • With the recent activation of the offshore wind power industry, there has been a development of power plants with a scale exceeding 400MW, comparable to traditional thermal power plants. Renewable energy, characterized by intermittency depending on the energy source, is a prominent feature of modern renewable power generation facilities, which are structured based on controllable inverter technology. As the integration of renewable energy sources into the grid expands, the grid codes for power system connection are progressively becoming more defined, leading to active discussions and evaluations in this area. In this paper, we propose a method for selecting optimal reactive power compensation capacity when multiple offshore wind farms are integrated and connected through a shared interconnection facility to comply with grid codes. Based on the requirements of the grid code, we analyze the reactive power compensation and excessive stability of the 400MW wind power generation site under development in the southwest sea of Jeonbuk. This analysis involves constructing a generation site database using PSS/E (Power System Simulation for Engineering), incorporating turbine layouts and cable data. The study calculates reactive power due to charging current in internal and external network cables and determines the reactive power compensation capacity at the interconnection point. Additionally, static and dynamic stability assessments are conducted by integrating with the power system database.

Factors Influencing Satisfaction of Branded App and Purchasing Intention: Moderation Role of Product Involvement (브랜드 앱 만족도와 구매의도의 영향요인: 제품관여도의 조절효과)

  • Jin Xinhua;SooYeon Chung;Cheol Park
    • Information Systems Review
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    • v.18 no.4
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    • pp.121-140
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    • 2016
  • Today, consumers are interested in branded apps as new marketing channels. Consumers do not have ready access to information that will enable them to judge the quality of a particular product or service before purchase, but they will gain such information with branded apps. As they need to be actively chosen and downloaded to users' smartphone by the users themselves, branded apps have greater marketing effectiveness and influence than traditional channels. Therefore, corporations that place emphasis on interactions with customers anticipate a new marketing effect with their branded apps. With previous research on smartphone applications as a background, this research finds key factors in branded apps that influence users' satisfaction. Additionally, the study centers on the relationship in which satisfaction in the branded app significantly influences the purchase intention for the branded product/service.

A Study on Wearable Augmented Reality-Based Experiential Content: Focusing on AR Stone Tower Content (착용형 증강현실 기반 체험형 콘텐츠 연구: AR 돌탑 콘텐츠를 중심으로)

  • Inyoung Choi;Hieyong Jeong;Choonsung Shin
    • Smart Media Journal
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    • v.13 no.4
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    • pp.114-123
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    • 2024
  • This paper proposes AR stone tower content, an experiential content based on wearable augmented reality (AR). Although wearable augmented reality is gaining attention, the acceptance of the technology is still focused on specialized applications such as industrial sites. On the other hand, the proposed AR stone tower content is based on the material of 'stone tower' so that general users can relate to it and easily participate in it, and it is organized to utilize space in a moving environment and find and stack stones based on natural hand gestures. The proposed AR stone tower content was implemented in the HoloLens 2 environment and evaluated by general users through a pilot exhibition in a small art museum. The evaluation results showed that the overall satisfaction with the content averaged 3.85, and the content appropriateness for the stone tower material was very high at 4.15. In particular, users were highly satisfied with content comprehension and sound, but somewhat less satisfied with object recognition, body adaptation, and object control. The above user evaluations confirm the resonance and positive response to the material, but also highlight the difficulties of the average user in experiencing and interacting with the wearable AR environment.

Exploring the Effects of Passive Haptic Factors When Interacting with a Virtual Pet in Immersive VR Environment (몰입형 VR 환경에서 가상 반려동물과 상호작용에 관한 패시브 햅틱 요소의 영향 분석)

  • Donggeun KIM;Dongsik Jo
    • Journal of the Korea Computer Graphics Society
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    • v.30 no.3
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    • pp.125-132
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    • 2024
  • Recently, with immersive virtual reality(IVR) technologies, various services such as education, training, entertainment, industry, healthcare and remote collaboration have been applied. In particular, researches are actively being studied to visualize and interact with virtual humans, research on virtual pets in IVR is also emerging. For interaction with the virtual pet, similar to real-world interaction scenarios, the most important thing is to provide physical contact such as haptic and non-verbal interaction(e.g., gesture). This paper investigates the effects on factors (e.g., shape and texture) of passive haptic feedbacks using mapping physical props corresponding to the virtual pet. Experimental results show significant differences in terms of immersion, co-presence, realism, and friendliness depending on the levels of texture elements when interacting with virtual pets by passive haptic feedback. Additionally, as the main findings of this study by statistical interaction between two variables, we found that there was Uncanny valley effect in terms of friendliness. With our results, we will expect to be able to provide guidelines for creating interactive contents with the virtual pet in immersive VR environments.

The Effects of Gamification of e-Learning Platforms on Engagement: Focusing on Moderating Effects of Interaction, Difficulty, and Length (e-러닝 플랫폼의 게임화가 인게이지먼트에 미치는 영향: 상호작용, 스터디 난이도, 스터디 길이의 조절효과를 중심으로)

  • Ohsung Kim;Jungwon Lee
    • Information Systems Review
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    • v.26 no.1
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    • pp.73-91
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    • 2024
  • Recently, e-learning platforms are rapidly growing by innovating the education industry by applying various IT technologies. Because student participation in the online environment is considered a prerequisite for learning, low participation rates are considered one of the most important issues determining the performance of e-learning platforms. Gamification has grown rapidly over the past decades and is highly valued for its applicability in education because it is expected to enhance learning motivation. However, despite the interest of researchers, previous studies have reported conflicting results on the effect of gamification on participation rates in the context of e-learning platforms, and have mainly studied structural gamification, but have not sufficiently addressed the effects of content gamification. In this context, this study aims to analyze the effect of content gamification on e-learning platform engagement and to explore the boundary conditions moderating this effect. For empirical analysis, 5,017 data registered from February 11, 2022 to May 31, 2022 were analyzed for the education platform entry (https://playentry.org). The propensity score matching method and Poisson multilevel regression model were applied as analysis methods. As a result of the analysis, content gamification had a statistically significant effect on engagement, and the interaction effects of interaction and content difficulty were statistically significant.

Development of a complex failure prediction system using Hierarchical Attention Network (Hierarchical Attention Network를 이용한 복합 장애 발생 예측 시스템 개발)

  • Park, Youngchan;An, Sangjun;Kim, Mintae;Kim, Wooju
    • Journal of Intelligence and Information Systems
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    • v.26 no.4
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    • pp.127-148
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    • 2020
  • The data center is a physical environment facility for accommodating computer systems and related components, and is an essential foundation technology for next-generation core industries such as big data, smart factories, wearables, and smart homes. In particular, with the growth of cloud computing, the proportional expansion of the data center infrastructure is inevitable. Monitoring the health of these data center facilities is a way to maintain and manage the system and prevent failure. If a failure occurs in some elements of the facility, it may affect not only the relevant equipment but also other connected equipment, and may cause enormous damage. In particular, IT facilities are irregular due to interdependence and it is difficult to know the cause. In the previous study predicting failure in data center, failure was predicted by looking at a single server as a single state without assuming that the devices were mixed. Therefore, in this study, data center failures were classified into failures occurring inside the server (Outage A) and failures occurring outside the server (Outage B), and focused on analyzing complex failures occurring within the server. Server external failures include power, cooling, user errors, etc. Since such failures can be prevented in the early stages of data center facility construction, various solutions are being developed. On the other hand, the cause of the failure occurring in the server is difficult to determine, and adequate prevention has not yet been achieved. In particular, this is the reason why server failures do not occur singularly, cause other server failures, or receive something that causes failures from other servers. In other words, while the existing studies assumed that it was a single server that did not affect the servers and analyzed the failure, in this study, the failure occurred on the assumption that it had an effect between servers. In order to define the complex failure situation in the data center, failure history data for each equipment existing in the data center was used. There are four major failures considered in this study: Network Node Down, Server Down, Windows Activation Services Down, and Database Management System Service Down. The failures that occur for each device are sorted in chronological order, and when a failure occurs in a specific equipment, if a failure occurs in a specific equipment within 5 minutes from the time of occurrence, it is defined that the failure occurs simultaneously. After configuring the sequence for the devices that have failed at the same time, 5 devices that frequently occur simultaneously within the configured sequence were selected, and the case where the selected devices failed at the same time was confirmed through visualization. Since the server resource information collected for failure analysis is in units of time series and has flow, we used Long Short-term Memory (LSTM), a deep learning algorithm that can predict the next state through the previous state. In addition, unlike a single server, the Hierarchical Attention Network deep learning model structure was used in consideration of the fact that the level of multiple failures for each server is different. This algorithm is a method of increasing the prediction accuracy by giving weight to the server as the impact on the failure increases. The study began with defining the type of failure and selecting the analysis target. In the first experiment, the same collected data was assumed as a single server state and a multiple server state, and compared and analyzed. The second experiment improved the prediction accuracy in the case of a complex server by optimizing each server threshold. In the first experiment, which assumed each of a single server and multiple servers, in the case of a single server, it was predicted that three of the five servers did not have a failure even though the actual failure occurred. However, assuming multiple servers, all five servers were predicted to have failed. As a result of the experiment, the hypothesis that there is an effect between servers is proven. As a result of this study, it was confirmed that the prediction performance was superior when the multiple servers were assumed than when the single server was assumed. In particular, applying the Hierarchical Attention Network algorithm, assuming that the effects of each server will be different, played a role in improving the analysis effect. In addition, by applying a different threshold for each server, the prediction accuracy could be improved. This study showed that failures that are difficult to determine the cause can be predicted through historical data, and a model that can predict failures occurring in servers in data centers is presented. It is expected that the occurrence of disability can be prevented in advance using the results of this study.