• Journal of Space Technology and Applications
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• v.2 no.2
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• pp.146-168
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• 2022

Witnessing current military conflicts in South China Sea and Eastern Europe, most defense analysts evaluate one of the most serious security threat toward the US is coming from the superpower competitions with Russia and China. The main means for such super power hegemonic competitions is military power and space power is a key enabler to maximize the efficiency and effectiveness of military employment. Reflecting above circumstances, the space hegemonic competition between the Unites States and China is spreading into all aspects of national powers. Under such an environment, R.O.K needs to significantly develop national space power to preserve life and assets of people in space. On the other hand, the R.O.K has a lot of limitations in launching space assets into orbits by land-based space rockets due to its geographic locations. The limitation of rocket launching direction, the failure to secure a significant area enough to secure safety and the limitation to secure open area enough to build associated facilities are among them. On this paper, I will suggest the need to build the 2nd space rocket launching site after analyzing a lot of short-falls the current 'Naro' space center face, compared to those of advanced space powers around the world.

• Journal of Korea Foundry Society
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• v.41 no.6
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• pp.550-557
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• 2021

With the advent of the fourth industrial revolution, the interest in the internet of things (IoT) in manufacturing is growing, even at foundries. There are several types of process data that can be automatically collected at a foundry, but considerable amounts of process data are still managed based on handwriting for reasons such as the limited functions of outdated production facilities and process design based on operator know-how. In particular, despite recognizing the importance of converting process data into big data, many companies have difficulty adopting these steps willingly due to the burden of system construction costs. In this study, the field applicability of IoT-based devices was examined by manufacturing devices and applying them directly to the site of a centrifugal foundry. For the centrifugal casting process, the temperature and humidity of the working site, the molten metal temperature, and mold rotation speed were selected as process parameters to be collected. The sensors were selected in consideration of the detailed product specifications and cost required for each process parameter, and the circuit was configured using a NodeMCU board capable of wireless communication for IoT-based devices. After designing the circuit, PCB boards were prepared for each parameter, and each device was installed on site considering the working environment. After the on-site installation process, it was confirmed that the level of satisfaction with the safety of the workers and the efficiency of process management increased. Also, it is expected that it will be possible to link process data and quality data in the future, if process parameters are continuously collected. The IoT-based device designed in this study has adequate reliability at a low cast, meaning that the application of this technique can be considered as a cornerstone of data collecting at foundries.

• Journal of the Society of Disaster Information
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• v.18 no.1
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• pp.129-145
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• 2022

Purpose: This study aims at preparing an external evacuation system by setting up situation that may occur outside buildings in case of large-scale fire at buildings such as multiuse facilities and presenting appropriate response procedures and action instructions for evacuees and facility managers. Method: Major matters are summarized based on various situations which may occur outside in case of fire and the contents of fire manual. Necessary factors including risk alert standards in the event of fire and the role of building occupants are classified and then important issues are summarized. In addition, the definition of fire-related outside shelters and external evacuation routes are showed, and then the applicability to the shelters and the routes are reviewed for old apartments in Jung-gu among multi-dense facilities. Result: Four stages (attention, caution, alert, serious) for standards of fire risk warning are established with the results of the investigation and analysis, and guidelines for behavior for evacuees, facility owners, residents, managers are summarized and presented. In addition, the concept and role of external shelters are divided into primary to the third shelters, and matters related to the definition of each shelter and the establishment of evacuation routes are presented, and then considered them carefully. Conclusion: This study has highlighted the importance of suggesting a systematic plan to secure the safety for evacuees outside space of buildings with disorder and difficulty to control in the event of fire. Therefore, we are confident that it will be useful in making an integrated manual for inside and outside buildings.

• Journal of the Korean GEO-environmental Society
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• v.22 no.12
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• pp.5-13
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• 2021

Expandable steel pipe piles have been developed to ensure stability and reduce construction costs during underground floor remodeling and extension work. Expandable steel pipe piles are more economical and stable than micropiles. Extensible steel pipe pile is a method of improving the performance of steel pipes by expanding steel pipes underground. In this paper, the changes in buckling strength according to the shape of steel pipes in an extended steel pipe pile were identified, a numerical analysis model was developed to determine the expended part effect of bumps due to steel pipe expansion, and the optimal steel pipe expansion was calculated through material tests. The larger the expansion diameter of the steel pipe and the greater the number of expanded part, the greater the buckling strength. Numerical results showed that the number of expanded part has a greater effect on buckling strength than the expansion rate. When the expansion rate is more than 1.2 times, it can be seen that as the number of expanded part increases, the effect of increasing buckling strength increases significantly. It was also noted that the expanded part effect of the bumps occur significantly when the extension angle is less than 45° and the expansion rate is 1.3 times higher. When the steel pipe is failure, the expanded rate is 20 to 32%, averaging 25.4%. Through the material test, it was analyzed that it is desirable to limit the maximum expansion rate for performing steel pipes to 16%.

• Tunnel and Underground Space
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• v.33 no.3
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• pp.169-188
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• 2023

Fires in tunnels are characterized by higher temperature rise and higher maximum temperatures compared to ground fires. For this reason, countries such as the Netherlands and Germany have developed separate temperature-time curves for use in tunnel fires. Fires in tunnels cause damage to the tunnel lining, such as loss of section and deterioration of the material properties. This study reviewed the design concept of fire stability of structures, section loss due to spalling, changes in physicochemical and mechanical properties of tunnel lining materials, fireproofing materials for structure safety, and fire damage prediction models. In order to secure the stability of a structure against fire, it is necessary to identify the type of structure and the possible fire load at the design stage, identify the expected section loss and damage range, and prepare for such damage through fireproofing materials. In this study, we have summarized the matters that can be referred to in performing such a series of tasks and presented our opinions on them.

• The Journal of the Convergence on Culture Technology
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• v.9 no.3
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• pp.75-79
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• 2023

ESG management means to thoroughly consider the investor's perspective when evaluating corporate value, and environmental, social, and governance issues are continuous and strategic monitoring issues in identifying risk and opportunity factors related to corporate management activities. In other words, the perspective of value creation is reflected in business relationships. The fundamental purpose of ESG management is continuous business value creation and thorough management of investment risks and business transactions in contractual relationships. It is also a requirement of linked investors. The field that Korean companies are currently experiencing the most is the recognition that 'ESG information collection is necessary and maintenance must be prioritized' in investor IR and global sales and marketing departments, and the primary need for this is emerging. In addition, as the legal affairs office, environmental safety department, and human resources department, which conduct compliance management, carry out related tasks, clarity at the organizational level must precede in order to properly establish an information integration and management system. It covers the scope of securing new market opportunities such as management, disclosure and communication. Therefore, in regard to the newly emerging ESG management and response methods, it is necessary to review and implement it repeatedly so that sustainable exchange profits can be created by simultaneously managing non-financial risks as well as efforts to enhance corporate value for financial returns.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.23 no.1
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• pp.153-166
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• 2024

The digitalization of tasks for smart construction requires the smooth exchange of digital data among stakeholders to be effective, but there is a lack of digital data standardization and utilization methods. This paper proposes a digital construction information structure to transform information from road construction sites into digital formats. The study targets include significant tasks, such as work planning, scheduling, safety management, and quality control. The key to the construction information structure is separating construction information into objects and activities, defining unit works by combining these two types of information to ensure flexibility in representing and modifying construction information. The objects and activities have their respective hierarchical structures, which are defined flexibly to match the actual content. This structure achieves both efficiency and detail. The pilot structure was applied to highway construction projects and implemented digitally using general formats. This study enables the digitalization of road construction processes that closely resemble reality, accelerating the digital transformation of the civil engineering industry by developing a digital twin of the entire road construction lifecycle.

• Journal of Bio-Environment Control
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• v.21 no.3
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• pp.163-169
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• 2012

We have conducted three experiments to develop a fertilizer-dissolving apparatus used in fertigation or hydroponics cultivation in order to decrease the fertilizer dissolving time and labor input via automation. All of the experiments were conducted twice. In the first experiment, four selected treatments were tested to dissolve fertilizers rapidly. The first treatment was to dissolve fertilizer by spraying water with a submerged water pump, placed in the nutrient solution tank. The water was sprayed onto fertilizer, which is dissolved and filtered through the hemp cloth mounted on the upper part of the nutrient solution tank (Spray). The second treatment was to install a propeller on the bottom of the nutrient solution tank (Propeller). The third treatment was to produce a water stream with a submerged water pump, located at the bottom of the tank (Submerged). Finally, the fourth treatment was to produce an air stream through air pipes with an air compressor located at the bottom of the tank (Airflow). The Spray treatment was found to take the shortest time to dissolve fertilizer, yet it was inconvenient to implement and manage after installation. The Airflow treatment was thought to be the best method in terms of the time to dissolve, labor input, and automation. In the second experiment, Airflow treatment was investigated in more detail. In order to determine the optimal number of air pipe arms and their specification, different versions of 6- and 8-arm air pipe systems were evaluated. The apparatus with 6 arms (Arm-6) that was made of light density polyethylene was determined to be the best system, evaluated on its time to dissolve fertilizer, easiness to use regardless of the lid size of the tank, and easiness to produce and install. In the third experiment, the Submerged and Arm-6 treatments were compared for their dissolving time and economics. Arm-6 treatment decreased the dissolving time by 8 times and proved to be very economic. In addition, dissolving characteristics were investigated for $KNO_3$, $Ca(NO_3)_2{\cdot}4H_2O$, and Fe-EDTA.

• Journal of Mushroom
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• v.15 no.4
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• pp.223-228
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• 2017

This study was conducted to investigate the effects of fermented spent mushroom substrates (F-SMS) of Flammulina velutipes on growth performance, carcass traits, and economic characteristics of Hanwoo steers. A yeast strain (Saccharomyces sp. UJ14) and Bacillus strain (Bacillus sp. UJ03) isolated from fresh spent mushroom substrates of Flammulina velutipes were used as probiotics to prepare F-SMS. Twenty-four Hanwoo steers (14 months old) were allocated to three dietary treatments via a randomized block design and were slaughtered at 30 months of age. These treatment groups included Control (TMR), T1 (TMR containing 10% of F-SMS) group, and T2 (TMR containing 30% of F-SMS). Body weight gain was not influenced by the experimental diets. DM and TDN intakes in the finishing period were significantly (p < 0.05) greater in group T1 than in other groups. CP intake was significantly (p < 0.05) greater in group T2 than in other groups during the whole experimental period. Among carcass traits, rib-eye area and back fat thickness tended to increase with F-SMS supplementation. The appearance rate (%) of a meat yield more than grade A was the highest in group T1. The net profits increased by 1.2% and 13.3% in groups T1 and T2, respectively. In conclusion, if a proper feeding program (including feed safety) can be ensured, spent mushroom substrates of Flammulina velutipes can prove to be a highly profitable feed source for Hanwoo steers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.131-138
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• 2018

In this study, we investigated the trend of technological development in major countries related to the propulsion equipment of railway vehicles. The propulsion system is the main equipment of electric vehicles. A lot of time and investment are required in order to ensure the development of technology. Therefore, developed countries have maximized their effort to develop technologies with safety, reliability, and convenience of maintenance. They have also done their utmost to prevent technology transfer to other countries after the development of new technologies. For example, Toshiba of Japan developed a new 3,300V/1,500 A class IGBT power device, but was reluctant to export it to foreign countries in order to protect this technology. In this study, we analyzed the patents applied for related to propulsion control systems and presented the direction of development during the technical development of these systems. The patent analysis of the core technologies was conducted using the Thomson Innovation DB. We examined the number of patents applied for by country, year and major applicant. As a result of the analysis, it was found that the proportion of patent applications per country was in the order of China, 48%, Europe 16.6%, and the United States 14.9%. The patent situation of the top 10 principal applicants revealed that (the top three were?) ABB 14%, GE 13%, and CRRC 12%. At the same time, we also conducted a qualitative analysis of the level of technical development by evaluating such factors as the influence index, quotation, market securing power and citation. Based on the result of the patent analysis, we presented the direction of technical development of the propulsion control equipment of railway vehicles. Based on the analysis results, it was found that domestic applicants considerably reduced their efforts to protect their patents from foreign companies. Nowadays, most of the electric motors used in Korea are induction motors. In advanced countries, permanent magnet electric motors are employed in new railway lines. Therefore, intensive investment is needed in new developments.