• International Journal of Advanced Culture Technology
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• v.9 no.1
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• pp.224-241
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• 2021

According to data from the National Police Agency, 75.5 percent of dead traffic accidents in Korea are truck accidents. About 1,000 people die in cargo truck accidents in Korea every year, and two to three people die in cargo truck accidents every day. In the survey, Korean cargo workers answer poor working conditions as an important cause of constant truck accidents. COVID 19 is increasing demand for non-face-to-face logistics. The inefficiency of the Korean transportation system is leading to excessive work burden for small logistics The inefficiency of the Korean transportation system is causing excessive work burden for small individual carriers. The inefficiency of the Korean transportation system is also evidenced by the number of deaths from logistics industry disasters that have risen sharply since 2020. Small and medium-sized Korean Enterprises located in CIPs (Connected Industrial Parks) often do not have smart access certification systems. And as a result, a lot of transportation time is wasted at the final destination stage. In the logistics industry, time is the cost and time is the revenue. The logistics industry is the representative industry in which time becomes money. The smart access authentication system architecture proposed in this paper allows small logistics private carriers to improve legal stability, and SMEs (Small and Medium-sized Enterprises) in CIPs to reduce logistics transit time. The CIPs smart access system proposed in this paper utilizes the currently active Mobile OTP (One Time Password), which can significantly reduce system design costs, significantly reduce the data capacity burden on individual cell phone terminals, and improve the response speed of individual cell phone terminals. It is also compatible with the OTP system, which was previously used in various ways, and the system reliability through the long period of use of the OTP system is also high. User customers can understand OTP access systems more easily than other smart access systems.

• Korean Journal of Metals and Materials
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• v.56 no.12
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• pp.915-920
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• 2018

With the development of modern microelectronics technologies, the power density of electronic devices is rapidly increasing, due to the miniaturization or integration of device elements which operate at high frequency, high power conditions. Resulting thermal problems are known to cause power leakage, device failure and deteriorated performance. To relieve heat accumulation at the interface between chips and heat sinks, thermal interface materials (TIMs) must provide efficient heat transport in the through-plane direction. We report on the enhanced thermal conduction of $Al_2O_3-based$ polymer composites, fabricated by the surface wetting and texturing of thermally conductive hexagonal boron nitride(h-BN) nanoplatelets with large anisotropy in morphology and physical properties. The thermally conductive polymer composites were prepared with hybrid fillers of $Al_2O_3$ macro beads and surface modified h-BN nanoplatelets. Hexagonal boron nitride (h-BN) has high thermal conductivity and is one of the most suitable materials for thermally conductive polymer composites, which protect electronic devices by efficient heat dissipation. In this study, we synthesized hexagonal boron nitride nanoparticles by the pyrolysis of cost effective precursors, boric acid and melamine. Through pyrolysis at $900^{\circ}C$ and subsequent annealing at $1500^{\circ}C$, hexagonal boron nitride nanoparticles with diameters of ca. 50nm were synthesized. We demonstrate that the addition of a small amount of calcium fluoride ($CaF_2$) during the preparation of the melamine borate adduct significantly enhanced the crystallinity of the h-BN and assisted the growth of nanoplatelets up to 100nm in diameters. The addition of a small amount of h-BN enhanced the thermal conductivity of the $Al_2O_3-based$ polymer composites, from 1.45W/mK to 2.33 W/mK.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.1
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• pp.26-36
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• 2021

The topic of this study is the field of humanitarian logistics for disaster response. Many existing studies have revealed that compliance with the golden time in response to a disaster determines the success or failure of relief activities, and logistics costs account for 80% of the disaster response cost. Besides, the agility, responsiveness, and effectiveness of the humanitarian logistics system are emphasized in consideration of the disaster situation's characteristics, such as the urgency of life-saving and rapid environmental changes. In other words, they emphasize the importance of logistics activities in disaster response, which includes the effective and efficient distribution of relief supplies. This study proposes a mathematical model for establishing a transport plan to distribute relief supplies in a disaster situation. To determine vehicles' route and the amount of relief for cities suffering a disaster, it mainly considers the urgency, effectiveness (restoration rate), and uncertainty in the logistics system. The model is initially developed as a mixed-integer nonlinear programming (MINLP) model containing some nonlinear functions and transform into a Mixed-integer linear programming (MILP) model using a logarithmic transformation and piecewise linear approximation method. Furthermore, a minimax problem is suggested to search for breakpoints and slopes to define a piecewise linear function that minimizes the linear approximation error. A numerical experiment is performed to verify the MILP model, and linear approximation error is also analyzed in the experiment.

• Journal of architectural history
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• v.29 no.6
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• pp.101-112
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• 2020

This study focuses on the construction of Gyeongbokgung Palace in the second year of King Gojong's reign, which has been spotlighted for political and economic history. The author analyzed the contents of wood procurement with the Yeonggeon Diary, which records each day of construction site. The results are as follows: First, the 2nd year of King Gojong's reign, Yeonggeon of Gyeongbokgung Palace, was a new building that reflected the old system and 270 years of changed environment on the existing site. Despite the poor economic conditions, it began with years of effort and voluntary volunteer work and dedication. Second, the priority of timber transport was recruiting people in the whole process and the supply and demand of transportation tools. Carrying lumber from the mountains to the riverside and floating it at the right time were all a matter of manpower. Soldiers and carts were used to carry timber that arrived in Hangang River to the construction site. The cart was a consumable product, so it was necessary to continuously use the wood to make cart at the site. Third, fire and flood were the biggest obstacles to the Yeonggeon schedule of Gyeongbokgung Palace. Especially the fire was fatal. It was difficult to extinguish the fire in temporary structure, where was the storage for wood to construct. These disasters greatly affected the construction cost and construction period. Wood procurements of Gyeongbokgung Palace were based on public offerings. At the same time, recycled materials from other palace wood and nearby houses, nationwide buying of private mountain wood, the logging of royal tombs and some of the buildings of Gyeonghui Palace and Changgyeong Palace were relocated.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.4
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• pp.559-569
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• 2022

Infrastructure engineering is a field that supports construction (assembly) as a representative industry that creates high added value and jobs by combining science and technology with knowledge, though its importance is underestimated. According to a report from the Ministry of Land, Infrastructure and Transport (Korea), the value-added rate (65.3%) of the engineering industry and the employment inducement coefficient (14 employees per billion won) are three times higher than in manufacturing. In particular,the forward value chain (such as project management and basic design) accounts for less than 10~15% of the total project cost but determines the overall price and quality of the infrastructure facilities. In this study, a work break-down system, design support module and database development method for road design projects for design platform development is presented. Based on the presented development method, a cloud-based infrastructure design platform's prototype is developed. The developed infrastructure engineering platform is expected to provide a web-based design work environment without time/space restrictions and greatly contribute to winning overseas business orders and securing competitiveness.

• Nuclear Engineering and Technology
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• v.54 no.7
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• pp.2592-2598
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• 2022

Research groups in the field of PET instrumentation are studying time-of-flight(TOF) technology to improve the signal-to-noise ratio of PET images. Scintillation light transport and collection plays an important role in improving the coincidence resolving time(CRT) of PET detector based on a pixelated crystal array. Four crystal arrays were designed by the different optical reflection configuration such as external reflectors and surface treatment on the CRT and compared with the light output, energy resolution and CRT. The design proposed in the study was composed of 8 × 8 LYSO crystal array consisted of 3 × 3 × 15 mm³ pixels. The entrance side was roughened while the other five surfaces were polished. Four sides of all crystal pixels were wrapped with ESR-film, and the entrance surface was covered by Teflon-tape. The design provided an excellent timing resolution of 210 ps and improved the CRT by 16% compared to the conventional method using a polishing treatment and ESR-film. This study provided a method for improving the light output and CRT of a pixelated scintillation crystal-based brain TOF PET detector. The proposed configuration might be an attractive detector design for TOF brain PET requiring fast timing performance with high cost-effectiveness.

• International Journal of Computer Science & Network Security
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• v.22 no.7
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• pp.443-450
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• 2022

The method of studying 3D-technologies abroad and in Ukraine is considered. The analysis of educational resources and experience of use of the equipment in branch is carried out. The didactic principles of the educational process for 3D-printing specialists are determined. The use of FDM technology and the ability to minimize the occurrence of defects in the future have been studied. An analysis of the international experience of the educational process of relevant specialists in the field. The content of training for 3D printing specialists has been developed. The experience of using 3D-technologies is described and the list of recommendations for elimination of defects during production of products by means of additive technologies is made. The recommendations will be useful not only for beginners, but also for experienced professionals in additive technologies. The need to study such experience is the main condition for the development of enterprises in Ukraine that plan to automate their own production. A 3D printing engineer must know the basics of economics and marketing, because his responsibilities include optimizing workflows to reduce the cost and speed up printing. Therefore, the knowledge gained from practical experience presented and in building for learning 3D printing engineers by the authors will be important.

• Journal of the Korean GEO-environmental Society
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• v.23 no.12
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• pp.41-53
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• 2022

After industrialization has been started, mankind needs and consumes more resources. Now, the resources depletion is a serious problem in the Earth. However, there are infinite resources in the Space. Especially, the Moon is the closest planet and has much resources, including Helium-3 and rare earths, which are needed to human being in the future. Humanity needs to reside on the moon to harvest these resources. For the resident, much resources, such as food, construction, and industrial materials, are needed. However, to transport these resources to the Moon from the Earth, an astronomical cost should be consumed. Thus, research is underway to support human activities by procuring resources locally. This is called In-Situ Resources Utilization (ISRU), which is the essential technology for the space development. In this paper, the reason why ISRU is essential and the its status are introduced and future research projects will be explained.

• International Journal of Computer Science & Network Security
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• v.22 no.9
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• pp.353-357
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• 2022

This article identifies the problems and substantiates the directions for the development of distance learning technologies in the training of personnel. An example of using digital media to create a remote access laboratory is given. The article is devoted to the definition of the main aspects of the organization of distance education. Rapid digitization, economic, political and social changes taking place in Ukraine necessitate the reform of the education system. First of all, it concerns meeting the educational needs of citizens throughout their lives, providing access to educational and professional training for all who have the necessary abilities and adequate training. The most effective solution to the above-mentioned problems is facilitated by distance learning. The article analyzes the essence and methods of distance learning organization, reveals the features of the use of electronic platforms for the organization of this form of education in different countries of the world. The positive characteristics of distance learning are identified, namely: extraterritoriality; savings on transport costs; the interest of modern youth in the use of information tools in everyday life; increase in the number of students; simplicity and accessibility of training; convenient consultation system; democratic relations between the student and the teacher; convenience for organizations in training their employees without interrupting their regular work; low level of payment for distance education compared to traditional education; individual learning pace; new teacher status. Among the negative features of online education, the author refers to the following problems: authentication of users during knowledge verification, calculation of the teacher's methodological load and copyright of educational materials; the high labor intensity of developing high-quality educational content and the high cost of distance learning equipment; the need to provide users with a personal computer and access to the Internet; the need to find and use effective motivation mechanisms for education seekers.

• Journal of the Korea Society for Simulation
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• v.19 no.4
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• pp.43-50
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• 2010

Recently, the Internet telephony has been used rather than the traditional telephony by many Internet users, with low cost. Session Initiation Protocol(SIP) is the standard of application layer protocol for establishment and disconnection of the session for Internet telephony. SIP mainly runs over the UDP for transport. So in case of the loss of the INVITE request message, the message is retransmitted by an appropriate timer for reliable transmission of the UDP message. Though the retransmission is useful for ensuring the reliability of SIP messages sent by the users, it may cause the overload traffic in the SIP proxy server. The overload in SIP proxy servers results in the loss of many input messages. This paper presents a non-linear overload control algorithm to resolve the overload condition of the server. we simulate our proposed algorithm using the network simulator ns-2. The simulation results show that the throughput of the server with the proposed algorithm have been improved about 12% compared to the existing linear control algorithm.