• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7244-7249
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• 2015

In this study, in order to asses the structural performance of trapezoidal PSC girder using a socket joint system and it is possible to calculate the optimized cross-section of the web element tests were carried out for each specimens. we conducted a socket joint performance test, web bending and shear performance tests and all tests were performed at 4 point loading method. The initial crack load of socket joint specimen was significantly lower than the reference specimen but post peak behavior was no significant differences. And the length of the loop joint of the reinforcing bars had no significant effect on the maximum load. As a web shear tests, to obtain a maximum load of the specimen has a prestressing rod reinforced at tension side. As a web flexural tests, to obtain higher diagonal cracking load in specimen of reinforced using prestressing rod than reference specimen.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.3
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• pp.499-505
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• 2018

Shipping and logistics safety, security system is strengthening worldwide, the development of shipping and logistics safety security core technology for national security logistics system construction has been carried out. In addition, it is necessary to localize the Array Detection System, which is a core component of the container search machine, to cope with the 100% pre-inspection of the container scheduled for 2018 in the United States. In this research, we propose a test software program developed by using TI-RTOS (Texas Instruments - Real Time Operating System) with a test digital signal processing board which is developed self development. We have developed a program that can test GPIO, SRAM, TCP/IP, and SDcard using M4 MCU. Also we propose a study on a self-developed Digital Signal Processing Board among the array detection systems that replace foreign products. We have developed a test board that can test M4 MCU and developed an X-Ray Detector Digital Signal Processing Board that combines MCU and FPGA.

• Korean Security Journal
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• no.42
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• pp.423-447
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• 2015

This paper gives analyses on the historical origin where features from social punishment and re-socialization in North Korea have been developed. The process of the development largely consists of three periods, that is, the period of nation construction (1945-1950), the period of Korean War (1950-1953), the period of nation reconstruction (1950-1961). This paper provides that features from punishment and re-socialization have been developed during the historical transformation from pre-Korean War to post-Korean War. The 'wartime socialism system' had been established in the course of reconstruction of postwar nation. In the system, North Korean had been embraced into the structure of re-socialization in its production unit and living space.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.26 no.1
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• pp.9-16
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• 2008

Korea's GIS market has been proliferating since the 1990s, but still its scale and the structure require overall rearrangements. Recently as the needs and initiatives from central and local governments go stronger to drive 'u-City(ubiquitous City)' developments, there are much more demand of spatial information from sectors like city management, construction, environment and so on. Through the merge between GIS and the advanced Information and Telecommunication Technology, the introduction of new Ubiquitous IT is swiftly changing GIS market environments, so the GIS industry is to be prepared for this trend. The pioneering developments of Ubiquitous-related GIS technologies are expected to highly boost spatial data and related industries, and the pre-occupancy of those technologies in the world would enable the expansion of overseas export market. In the context of these epoch-making chances, by looking into the actual status of GIS industry, this study is to investigate the actual accomplishments to foster the GIS industry through Korea's National GIS Master Plan. Thereby, impending issues will be discussed to provide useful problem-solving suggestions.

• Structural Engineering and Mechanics
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• v.74 no.3
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• pp.395-406
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• 2020

Many prefabricated concrete frame joints have been proposed, and most of them showed good seismic performance. However, there are still some limitations in the proposed fabricated joints. For example, for prefabricated prestressed concrete joints, prefabricated beams and prefabricated columns are assembled as a whole by the pre-stressed steel bar and steel strand in the beams, which brings some troubles to the construction, and the reinforcement in the core area of the joints is complex, and the mechanical mechanism is not clear. Based on the current research results, a new type of fabricated joint of prestressed concrete beams and confined concrete columns is proposed. To study the seismic performance of the joint, the quasi-static test is carried out. The test results show that the nodes exhibit good ductility and energy dissipation. According to the experimental fitting method and the "fixed point pointing" law, the resilience model of this kind of nodes is established, and compared with the experimental results, the two agree well, which can provides a certain reference for elasto-plastic seismic response analysis of this type of structure. Besides, based on the analysis of the factors affecting the shear capacity of the node core area, the formula of shear capacity of the core area of the node is proposed, and the theoretical values of the formula are consistent with the experimental value.

• 사회경제평론
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• v.31 no.3
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• pp.29-53
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• 2018

This study provides a model of inter-Korean economic cooperation suggesting that economic cooperation should be centered on industrial cooperation. As an independent economic zone, the two Koreas will go through a gradual and functional process of cooperation. Also, economic convergence through 'openness and integration' of both markets is a pre-requisite of successful economic integration on the Korean peninsula. This success of the process requires industrialization of North Korea. This study suggests a model of 'the Corea Industrial Development Community on the Korean Peninsula. It aims to support industrialization of the North Korean economy as well as promotion of South Korea's SME competitiveness. It would help meet the demand for improvement of living conditions of North Korean people. Main policy measures includes: 1) co-effort to develop North Korea's provincial industrial zones, 2) upgrading North Korea's 'Jangmadang' into a highly efficient distribution market. Finally, through the construction of the Joint Industrial Development Zone, it is necessary to create a production sharing module for both Korea's industries.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.2
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• pp.154-161
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• 2016

There are several existing studies for the weight estimation of offshore plants. However, most of them were applicable at the pre-FEED (Front End Engineering Design) stage. In this paper, a preliminary study on a method for the weight estimation and calculation of offshore EPC (Engineering Procurement Construction) projects is made for the use at the estimation stage after FEED. Based on literature surveys including ISO (International Organization for Standardization) 19901-5 about weight estimation, we proposes new weight factors and a weight curve. Weight factors defined in this study include MTO (Material Take-Off), estimated weight, FEED maturity factor, allowance factor, and contingency factor. The proposed method utilizes bottom-up approach for weight estimation and it can be used for the weight estimation and calculation of offshore EPC projects at the estimation stage.

• Communications of Mathematical Education
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• v.35 no.3
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• pp.295-322
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• 2021

This study was conducted for one semester through one group pretest-posttest design with 49 first-year middle school students to explore the effects of mathematics-centered STEAM class experiences on students' mathematical modeling abilities. The main results of this study are as follows: First, the results of the pre and post-mathematical modeling ability tests showed that the average score of posttest was improved compared to the pretest, and that the experiences of mathematics-centered STEAM classes provided in this study had a positive effect on improving the mathematical modeling ability of first-year middle school students. Second, STEAM classes were more effective in solving mathematical modeling problems that require students' creative and divergent thinking. Third, the content analysis of student responses for each subquestion showed that STEAM classes were especially more helpful in activating students' mathematical model construction and validating steps.

• Steel and Composite Structures
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• v.30 no.6
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• pp.535-550
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• 2019

Prestressed concrete (PC) bridges using corrugated steel webbing have emerged as one of the most promising forms of steel-concrete composite bridge. However, their long-term behavior is not well understood, especially in the case of large-span bridges. In order to study the time-dependent performance, a large three-span PC bridge with corrugated steel webbing was compared to a similar conventional PC bridge to examine their respective time-dependent characteristics. In addition, a three-dimensional finite element method with step-by-step time integration that takes into account cantilever construction procedures was used to predict long-term behaviors such as deflection, stress distribution and prestressing loss. These predictions were based upon four well-established empirical creep prediction models. PC bridges with a corrugated steel web were observed to have a better long-term performance relative to conventional PC bridges. In particular, it is noted that the pre-cambering for PC bridges with a corrugated steel web could be smaller than that of conventional PC bridges. The ratio of side-to-mid span has great influence on the long-term deformation of PC bridges with a corrugated steel web, and it is suggested that the design value should be between 0.4 and 0.6. However, the different creep prediction models still showed a weak homogeneity, thus, the further experimental research and the development of health monitoring systems are required to further progress our understanding of the long-term behavior of PC bridges with corrugated steel webbing.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.6
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• pp.359-366
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• 2018

Social infrastructure facilities that have been under construction since the country's high-growth period are undergoing rapid aging, and safety assessments of large structures such as bridge tunnels, which can be directly linked to large-scale casualties in the event of an accident, are necessary. Wireless smart sensor networks that improve SHM(Structural Health Monitoring) based on existing wire sensors are difficult to construct economical and efficient system due to short signal reach. The LPWAN, Low Power Wide Area Network, is becoming popular with the Internet of Things and it is possible to construct economical and efficient SHM by applying it to structural health monitoring. This study examines the applicability of LoRa LPWAN to structural health monitoring and proposes a channel usage pre-planning based LoRa network operation method that can efficiently utilize bandwidth while resolving conflicts between channels caused by using license - exempt communication band.