• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.5
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• pp.641-652
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• 2007

In this paper, a half-scaled substructure test was performed to evaluate the buckling and structural safety of an existing transmission tower subjected to wind load. A loading scheme was devised to reproduce the dead and wind loads of a prototype transmission tower, which uses a triangular jig that is mounted on the reduced model to which the similarity law of a half length was applied. As a result of the preliminary numerical analysis carried out to evaluate the stability of a specimen for the design load, is was confirmed that the calculated axial forces of tower leg members were distributed to $80{\sim}90%$ of an admissible buckling load. When the substructured transmission tower was loaded by 270% of its maximum admissible buckling load, it was failed due to the local buckling that is occurred in joints with weak constraints for out-of-plane behavior of leg members. By inspection of load-displacement curves, displacements and strains of members, it is considered that this local buckling was due to additional eccentric force by unbalanced deformation because the time that is reached to yielding stress due to the bending moment is different at each point of a same section.

• Journal of The Korean Association of Information Education
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• v.25 no.2
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• pp.265-277
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• 2021

With the development of technology, the concept of digital literacy is expanding from the focus of function and tool utilization to the extent of communication and participation in social and cultural contexts. In particular, learners' digital literacy capabilities are more important and necessary in remote learning environments such as Corona19. In this study, we studied how to improve digital literacy education through analysis and inspection of digital literacy shown in elementary school textbooks. To this end, we analyze it through compliance consisting of 8 fundamental pieces of knowledge, 20 sub technical skills, and 10 keys of competencies that constitute digital literacy. As a result of the study, the contents of digital literacy education in elementary school textbooks were presented centered on functions and tools, and as they were biased in certain areas, they were found to be lacking in systematicity and connectivity. Therefore, it proposed the composition of the curriculum system of digital literacy through the independence of elementary informatics curriculum, the specific composition of curriculum, and the strengthening of pre-service teachers' practical skills.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.6
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• pp.529-536
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• 2015

A defect could be generated in bolts for a use of oil filters for the manufacturing process and then may affect to the safety and quality in bolts. Also, fine defects may be imbedded in oil filter system. So it is very important that such defects be investigated and screened during the multiple manufacturing processes. Therefore, in order effectively to evaluate the fine defects, the FEM simulations were performed to make characterization in the crack detection of the bolts and the parameters such as number of turns of the coil, the coil size, applied frequency were calculated based on the simulation results. Simulations were carried out for the defect signal of eddy current probe. Exciter and receiver were utilized. In this paper, the FEM simulations were performed in both bobbin-type and pancake-type probe, both probes were optimized under Eddy current FEM simulations and the results of calculation were discussed.

• JSTS:Journal of Semiconductor Technology and Science
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• v.2 no.2
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• pp.132-140
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• 2002

This paper presents an ARM-based SOC bus transaction verification IP and the usage experiences in SOC designs. The verification IP is an AMBA AHB protocol checker, which captures legal AHB transactions in FSM-style signal sequence checking routines. This checker can be considered as a reusable verification IP since it does not change unless the bus protocol changes. Our AHB protocol checker is designed to be scalable to any number of AHB masters and reusable for various AMBA-based SOC designs. The keys to the scalability and the reusability are Object-Oriented Programming (OOP), virtual port, and bind operation. This paper describes how OOP, virtual port, and bind features are used to implement AHB protocol checker. Using the AHB protocol checker, an AHB simulation monitor is constructed. The monitor checks the legal bus arbitration and detects the first cycle of an AHB transaction. Then it calls AHB protocol checker to check the expected AHB signal sequences. We integrate the AHB bus monitor into Verilog simulation environment to replace time-consuming visual waveform inspection, and it allows us to find design bugs quickly. This paper also discusses AMBA AHB bus transaction coverage metrics and AHB transaction coverage analysis. Test programs for five AHB masters of an SOC, four channel DMAs and a host interface unit are executed and transaction coverage for DMA verification is collected during simulation. These coverage results can be used to determine the weak point of test programs in terms of the number of bus transactions occurred and guide to improve the quality of the test programs. Also, the coverage results can be used to obtain bus utilization statistics since the bus cycles occupied by each AHB master can be obtained.

• Journal of Digital Convergence
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• v.13 no.1
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• pp.269-274
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• 2015

According to the development of IT industry, prevalence of AOI equipment is spreading, and also requiring the high resolution of the camera used in the equipment. The weight of the camera is increased to obtain a high resolution, and thus increases the vibration displacement is a problem occurring in the picturing, camera motion control also becomes difficult. In this study, using a finite element analysis program NX/NASTRAN, the transient response of the camera was analysed which is subjected to an impact force due to inertia. The finite element analysis result is correlated with laser interferometer measurement. When AOI equipment is restructuring, the correlated finite element analysis model can be used to verify the authenticity of the new design.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.21 no.1
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• pp.145-155
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• 2018

Problems and improvement plan in ecological pathways created by Environmental Impact Assessment(EIA) were found based on 504 expost environmental impact survey reports submitted to the National Institute of Ecology in 2016. A total of five improvement plans have been proposed. First, the concept and composition principle of ecological pathways should be unified. Second, Guidelines for consultation on the EIA should be provided for each stage to be applied on-site. Third, if ecological pathway is constructed differently than the consultation, the punishment clauses should be applied to prevent formal composition of ecological pathways. Fourth, We need to prepare measures to strengthen basic research for the installation of ecological pathways. Fifth, We need to strengthen the expost inspection function to compensate for the poorly created of ecological pathways. It is believed that the problems of ecological pathways created by consultation on environmental impact assessment could be corrected in the future. And it is deemed possible to systematically manage ecological pathways.

• Journal of Aerospace System Engineering
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• v.12 no.3
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• pp.38-44
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• 2018

Military aircraft may have fatigue cracks in structurally weak areas due to multiple factors such as the accumulation of flight time while perform various missions and unpredictable air conditions. As a fatigue crack progresses, there is a risk that the structure will be destroyed in extreme cases, which can have a significant impact on flight safety. In this study, a cracking phenomenon was observed during the periodic inspection the inner support of the fairing, which is installed to protect the connection between the wing and the body of the aircraft. Therefore, a study on a series of quality improvement processes for reformation was described. In order to identify the causes of cracks, pre-load generation occurrence during the wing assembly process was investigated and a fracture analysis was performed. Also, the design of the support structure was suggested in terms of preventing recurrence of cracks. The structural integrity was verified using a stress and fatigue life analysis.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.9
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• pp.1083-1090
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• 2011

A steam generator poses many difficulties during the development of a sodium-cooled fast reactor because of the sodium-water-reaction problems. Until now, several types of steam generators have been developed, but the specifications of these generators differed in each country. Moreover, even if a country had developed a steam generator, it was not used in the subsequent reactor because the current techniques were not stabilized to select the proper steam generator. As a common development, the Benson steam cycle with few welding locations and high economical efficiency may be adopted. Moreover, the design is dwelled on the convenience of inspection, detection, control, and maintenance for the wear caused by sodiumwater reactions. The specifications of the designed steam generators were reviewed and the current technical problems for steam generators were analyzed. Concepts were proposed to overcome the current technical problems for steam generators.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.3
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• pp.207-215
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• 2013

This paper is channel assignment and scheduling techniques for efficient wireless AMI network. In AMI system, the multi-channel cluster network to be proposed defines the communication channel between NC (Network Coordinator) and CDA (Clustered Data Aggregator) as the network channel. CDA and OMD(Out Meter display) and communication channel between SMD(Smart Meter Device) are defined as the group channel. AMI network of the multi-channel cluster based in which the network channel and group channel is mixed increases the administration efficiency through the physical/logical consumer channel clustering. The reliability of inspection data through the channel use distinguished between the adjacent cluster is enhanced. In addition, the fast aggregation of data is possible and the size of a metering network is increased through the channel allocation of the multichannel cluster based.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.4
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• pp.1515-1518
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• 2015

Background: Leukoplakia is an asymptomatic and potentially malignant change in the oral mucosa and high frequencies have been reported among smokers. The present study concerned the prevalence of tobacco use and leukoplakia and also associations between the two. Study design: This cross sectional survey was conducted amongst the Gond tribal population of Kundam Block, Jabalpur district, Madhya Pradesh state, Central India during 2007 to 2009. Screening for leukoplakia was conducted by a medical officer with two mouth mirrors. It is only based on visual inspection and oral pathology was not performed. A semi-structured questionnaire was used to collect information on socio-demographic and smoking habits. Prevalence of leukoplakia among users and non-users of tobacco was calculated in terms of percentages. Results: Of 1,552 individuals aged more than 12 years of age who were screened, 144 (9.3%) were found to have oral leukoplakia. The prevalence of leukoplakia was significantly elevated among tobacco users as compared to non-users (11% vs 2.5%; p<0.001). The percentage of leukoplakia was almost similar in both tobacco smokers and chewers (9% vs 11%; p=0.304). However, the percentage of leukoplakia was especially high among those chewers who also smoked tobacco (21.9%). Conclusions: The findings of the present study showed a positive effect of tobacco use and prevalence of leukoplakia. Also the prevalence was very high among Gond tribe, a marginalized population living in central India. There is a need for effective screening and treatment of leukoplakia in this area.