• The Journal of the Convergence on Culture Technology
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• v.9 no.6
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• pp.1173-1178
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• 2023

In modern society, there is a tendency to emphasize efficiency and lead to detailed planning of team projects and individual tasks within organizations. In a 24-hour routine, the ability to use time effectively is considered an indicator of conscientiousness, and people try to imitate planned and organized people and utilize various systems to manage their daily lives. The reason why you want to perform a given task efficiently is because it affects the success or failure of the project by completing the task within a set period of time. Neglecting the project schedule is considered a major risk that threatens a successful outcome. This applies not only to large-scale organizational projects but also to individual life, and utilizes a variety of schedule management tools that emphasize time-based efficient management. In project management, it is necessary to carefully understand the detailed work progress rather than simply based on Today. In this paper, we propose an Android application that can manage schedules by accessing the user's project in units of tasks rather than dates, and introduce its implementation. The application we implemented in this paper can manage the project's goals and schedule by registering the project to which the user belongs. In addition, it provides the ability to approach work efficiently by visualizing the progress of the entire project or individual goals. As a result, users can use the application we propose in this paper to focus on their projects and manage schedules by task, thereby improving the overall efficiency of the project.

• Journal of the Institute of Convergence Signal Processing
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• v.24 no.2
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• pp.126-133
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• 2023

In this study, electromyography was obtained in the six muscle areas that move the joints of the two legs, and by analyzing it, an exercise robot system capable of gait rehabilitation was proposed in consideration of the individual's muscle state. Through this, the system was constructed to prevent the effect of exercise from decreasing because the patient's will was not reflected when walking exercise was simply provided automatically. As a result of the evaluation of the developed system, it was confirmed that the pedestrian rehabilitation robot system manufactured through this study had performance suitable for the design requirements, and it was also confirmed that the usability evaluation was comprehensively satisfactory. The results of this study are thought to be of great help to patients who are having difficulty in gait rehabilitation, and are believed to be helpful in the development of electromyography signal-based gait robot systems.

• Korean Journal of Optics and Photonics
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• v.35 no.1
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• pp.9-17
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• 2024

A plenoptic optical system for microscopy comprises an objective lens, tube lens, microlens array (MLA), and an image sensor. Numerical aperture (NA) matching between the tube lens and MLA is used for optimal performance. This paper extends performance predictions from NA matching to unmatching cases and introduces a computational technique for plenoptic configurations using optical analysis software. Validation by fabricating and experimenting with two sample systems at 10× and 20× magnifications resulted in predicted spatial resolutions of 12.5 ㎛ and 6.2 ㎛ and depth of field (DOF) values of 530 ㎛ and 88 ㎛, respectively. The simulation showed resolutions of 11.5 ㎛ and 5.8 ㎛, with DOF values of 510 ㎛ and 70 ㎛, while experiments confirmed predictions with resolutions of 11.1 ㎛ and 5.8 ㎛ and DOF values of 470 ㎛ and 70 ㎛. Both formula-based prediction and simulations yielded similar results to experiments that were suitable for system design. However, regarding DOF values, simulations were closer to experimental values in accuracy, recommending reliance on simulation-based predictions before fabrication.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.17 no.1
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• pp.1-12
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• 2022

This paper examines the influence of the portion of lead investors and investors' status on the investment performance of venture syndication. According to existing literature, multiple investors in VC syndicates can positively impact investment performance by investing both tangible and intangible resources in target companies based on market influence or high visibility. On the other hand, the presence of multiple leaders can cause conflicts in formulating and implementing investment strategy or free-riding problems or increase entry barriers for potential investors, lowering additional investment from existing investors. Therefore, we hypothesize that the relationship between proportion of lead investors and investment performance is inverted-U shape. Moreover, we predict that the status of VCs in the syndication will moderate the relationship between proportion of lead investors and investment performance since high-status actors are less likely to cooperate with or yield power to others. We tested these hypotheses using 24,677 VC syndicated investment data from 1991 to 2005 and found solid supports for the hypotheses. The findings suggest that firms need to consider relationship-based power dynamics among investors within a syndication and design effective role setting and coordination systems.

• Journal of Aerospace System Engineering
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• v.18 no.1
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• pp.53-63
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• 2024

Adopting an engine igniter with high efficiency and ignition performance is essential for reliable operation of liquid rocket engines. In this study, we developed a spark torch igniter for a 450 N-scale methane-oxygen liquid rocket engine by conducting numerical analyses, igniter manufacturing and validation. Specifically, we conducted a parametric study for maximizing the enthalpy at the igniter exit, specifically by adjusting the mass flow rate, nozzle area ratio, fuel-oxidizer mixture ratio, and the igniter length-to-diameter. The heat transferred via the igniter nozzle exit was computed using 3-dimensional numerical simulations. We also manufactured and tested the igniter based on a deduced design to confirm ignition performance of the designed spark torch igniter. The igniter developed through this study could contribute to the development of practical propulsion systems such as upper-stage engines of small launch vehicles.

• Animal Bioscience
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• v.37 no.3
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• pp.500-508
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• 2024

Objective: Due to current selection practices for increased egg production and peak persistency, the production profile, age at maturity, and body weight criteria for commercial layers are constantly changing. Body weight and age at the time of photostimulation will thus always be the factors that need to be adequately addressed among various production systems. The current study was carried out to determine the effects of pullets' body weight (low, medium, and heavy) on their performance, welfare, physiological response, and hormonal profile. Methods: With regard to live weight, 150 16-week-old pullets were divided into three groups using a completely randomized design (CRD) and held until the 50th week. One-way analysis of variance was used to evaluate the data under the CRD, and the least significant difference test was used to distinguish between treatment means. Results: In comparison to the medium and light birds, the heavy birds had higher body weight at maturity, an earlier age at maturity, and higher egg weight, eggshell weight, eggshell thickness, egg yolk index, breaking strength, egg surface area, egg shape index, egg volume, and hormonal profile except corticosterone. However, the medium and light birds had lower feed consumption rates per dozen eggs and per kilogram of egg mass than the heavy birds. Light birds showed greater body weight gain, egg production, and egg specific gravity than the other categories. At 20 weeks of age, physiological response, welfare aspects, and catalase were non-significant; however, at 50 weeks of age, all these factors-aside from catalase-were extremely significant. Conclusion: The findings of this study indicate that layers can function at lower body weights during photostimulation; hence, dietary regimens that result in lighter pullets may be preferable. Additionally, the welfare of the birds was not compromised by the lighter weight group.

• Journal of the Korean Geosynthetics Society
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• v.23 no.2
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• pp.43-52
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• 2024

Recent abnormal climate conditions have increased the risk of slope collapses, which frequently result in significant loss of life and property due to the absence of early prediction and warning dissemination. In this paper, we develop a slope condition analysis system using IoT sensors and AI-based camera to assess the condition of slopes. To develop the system, we conducted hardware and firmware design for measurement sensors considering the ground conditions of slopes, designed AI-based image analysis algorithms, and developed prediction and warning solutions and systems. We aimed to minimize errors in sensor data through the integration of IoT sensor data and AI camera image analysis, ultimately enhancing the reliability of the data. Additionally, we evaluated the accuracy (reliability) by applying it to actual slopes. As a result, sensor measurement errors were maintained within 0.1°, and the data transmission rate exceeded 95%. Moreover, the AI-based image analysis system demonstrated nighttime partial recognition rates of over 99%, indicating excellent performance even in low-light conditions. Through this research, it is anticipated that the analysis of slope conditions and smart maintenance management in various fields of Social Overhead Capital (SOC) facilities can be applied.

• Journal of The Korean Association For Science Education
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• v.29 no.4
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• pp.423-436
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• 2009

This study aims to develop an analytic framework that can be used to classify scientific models in science textbooks according to modes and attributes of representation and to investigate types of scientific models presented in the biology section of science textbooks for the $7^{th}$ to $10^{th}$ grades. The results showed that modes of representation of scientific models are related to the nature of sub-areas of biology sections. Generally, the iconic model and symbolic model were in dominant use, including drawings of organs and explanations of working of systems. However, the chapters on 'The Organization of Life' and 'The Continuity of Life' showed a relatively high frequency in use of the actual model. The theoretical model was presented in a part of 'The Continuity of Life', due to its highly abstract characteristics. Moreover, the gestural model and analogical model showed very low frequency. From the perspective of attributes of representation, frequency of the static model was very high, while one of the dynamic models was very low. Therefore, efforts to recognize the properties of scientific concepts more clearly and to develop diverse types of models that can represent the concepts adequately are required. Analysis of these types of scientific models can offer recognition of the usefulness and limitations of models in representing the concepts or phenomena, and can help us to design adequate models depicting particular properties of given concepts. Also, this type of analysis may motivate researchers to strive to reveal correct methods for and limits of using the scientific models that are presented in existing science textbooks, as well as to provide useful information to organize the science textbooks according to the revised $7^{th}$ national science curriculum.

• Journal of Family Resource Management and Policy Review
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• v.27 no.4
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• pp.49-62
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• 2023

In order to create an organizational culture that prevents women's career breaks and promotes economic activities, this study aimed at developing educational content for workplace culture improvement for both male and female workers working at small and medium-sized enterprises in Jeollanam-do. The core content composition and content design specifically consider the characteristics of Jeollanam-do based on an advisory meeting of the field experts and researchers to ensure the on-site utilization of the content and the validity and consistency of the teaching content. The educational content is divided into three areas: understanding, effectiveness, and the implementation of a gender-sensitive work-life balance organizational culture. The aim of the content is for all employees to understand the meaning of work-life balance and to improve the organizational culture of their company from the perspective of individuals, families, companies, and society. In particular, the intention was to personally identify and implement measures to improve a gender-equal work-life balance, not only at work, but also with regard to domestic labor and leisure time. Furthermore, the content is presented from a gender-sensitive perspective that encompasses diversity, systems, and programs targeting women, men, single people, married people, young people, the elderly, and people with disabilities - all these groups are explained as examples. The content emphasizes that we should all actively participate in improving the organizational culture of our companies. In addition, the Women's New Work Center should seek ways to increase the motivation for the voluntary participation by companies and strengthen the expertise of instructors in work-life balance education.

• Convergence Security Journal
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• v.24 no.1
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• pp.51-57
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• 2024

Although industrial control systems (ICSs) recently keep evolving with the introduction of Industrial IoT converging information technology (IT) and operational technology (OT), it also leads to a variety of threats and vulnerabilities, which was not experienced in the past ICS with no connection to the external network. Since various control command messages are sent to field devices of the ICS for the purpose of monitoring and controlling the operational processes, it is required to guarantee the message integrity as well as control center authentication. In case of the conventional message integrity codes and signature schemes based on symmetric keys and public keys, respectively, they are not suitable considering the asymmetry between the control center and field devices. Especially, compromised node attacks can be mounted against the symmetric-key-based schemes. In this paper, we propose message authentication scheme based on double hash chains constructed from cryptographic hash function without introducing other primitives, and then propose extension scheme using Merkle tree for multiple uses of the double hash chains. It is shown that the proposed scheme is much more efficient in computational complexity than other conventional schemes.