• International Journal of Aeronautical and Space Sciences
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• v.13 no.1
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• pp.64-73
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• 2012

Pointing stability of high precision observation satellites must satisfy the stringent requirements to perform at a designed level. As even a small vibrational disturbance can result in severe degradation of the optical performance, the effects of inorbit vibrational environment on the performance of optical payload must be predicted and analyzed in the design phase in order to ensure that the requirements imposed on the payload are fully met. In this paper, an integrated framework for the evaluation of the performance of optical payloads is developed. The developed simulation tool comprises of the reaction wheel induced disturbance model, state space model of a structure in modal form and Cassegrain reflector model. The performance degradation of the optical system due to jitter is expressed by using modulation transfer function (MTF) and image simulation. Moreover, vibration isolator model is also added to show the effectiveness of using a vibration isolator for the elimination of the effects of jitter in the acquisition of an image.

• Korean Chemical Engineering Research
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• v.61 no.2
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• pp.322-327
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• 2023

A design of experiments was evaluated in optimizing MOF-5 synthesis for acetylene adsorption. At first, mixture design was used to optimize precursor concentration, terephthalic acid, zinc acetate dihydrate and N,N-dimethylformamide. More specifically, 13 conditions with various molar ratios were designed by extreme vertices design method. After preparing the samples, XRD, N₂ physisorption and SEM analysis were performed for their characterization. Moreover, acetylene adsorption experiments were carried out over the samples under identical conditions. The optimal precursor composition for MOF-5 synthesis was predicted on a molar basis as follows: terephthalic acid : acetate dihydrate : dimethylformamide = 0.1 : 0.4 : 0.5. Thereafter, multi-level factorial design was designated to investigate the effect of synthesis reaction conditions such as temperature, time and stirring speed. By the statistical analysis of 18 samples designed, 4 reaction parameters were determined for additional adsorption experiments. Therefore, MOF-5 prepared under the synthesis time and temperature of 100 ℃ and 12 h, respectively, showed the maximum adsorption capacity of 15.1 mmol/g.

• Geomechanics and Engineering
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• v.34 no.2
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• pp.173-186
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• 2023

In order to prevent environmental pollution, initiatives to increase the sustainability of resources are supported by society. However, the performance of recycled materials does not generally match that of natural materials. This study looks into the use of geogrid to improve various types of recycled aggregates. For this purpose, five different recycled aggregates were created by recycling wastes from the construction industry. Besides, direct shear tests (DS tests) were carried out on these recycled aggregates to determine their shear strengths. Following that, a triaxial geogrid was placed in the recycled aggregates to provide reinforcement, and the DS tests were conducted on the reinforced recycled aggregates. The results of the tests were also compared to those of tests performed on natural aggregates (NA). In conclusion, it was found that the recycled aggregates have lower shear strengths than the NA. Nonetheless, when reinforced with geogrid, the shear strength of the recycled concrete aggregates (RCA) and construction and demolition wastes (CDW) exceeded that of the NA. Furthermore, the geogrid reinforcement increased the shear strength of the recycled crushed bricks (CB), though not to the level of the NA.

• International Journal of Advanced Culture Technology
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• v.12 no.2
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• pp.249-257
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• 2024

This study analyzes the current status and prospects of Iran's air defense network, focusing on the Russian-made S-300 system, and derives implications for the development of South Korea's air defense network. Iran's air defense network exhibits strengths such as long-range detection and interception capabilities, multi-target processing, high-altitude interception, and electronic warfare response. However, it also reveals weaknesses, including lack of mobility, difficulty in detecting low-altitude targets, obsolescence, training level of operating personnel, and vulnerability to electronic warfare. Real-world cases confirm these weaknesses, making the system susceptible to enemy evasion tactics, swarm drone attacks, and electronic warfare. Drawing from Iran's case, South Korea should establish a multi-layered defense system, strengthen low-altitude air defense and electronic warfare capabilities, foster the domestic defense industry for technological self-reliance, and enhance international cooperation. By addressing these aspects, South Korea can establish a robust air defense network and firmly protect its national security. Future research should aim to secure and analyze materials from the Iranian perspective for a more objective evaluation of Iran's air defense network and continuously track Iran's efforts to improve its air defense network and the trend of strengthening drone forces to predict changes in the Middle East security situation.

• Journal of Information Management
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• v.37 no.4
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• pp.69-91
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• 2006

The purpose of this study is to improve the effectiveness and quality of web service by analyzing the web service problems and suggesting the solutions through the expert service quality evaluation from the point of view of users and website quality evaluation by measurement tools for a whole NDSL website. In case of website analysis, this study analyzed the website completeness of NDSL site and looked into the problem that users can judge by intuition during their use of the site, and evaluated the searchability and usability for web-based service quality evaluation by centering on the service quality of database quality items. After the results of this analysis, it appeared that there was not a big problem on the use. But after searching, several problems were found on loading rates, website completeness, user sensitiveness, the protection of private information, metadata completeness, website accessability, etc. And as a result of the evaluation of website service quality, it does not show the all satisfactory results in the function of search methods and search result printing, mark list and the items related to full-text in the part of searchability and usability. However, comparing with the results of other information organizations, it shows the similar level of quality.

• Korean Journal of Poultry Science
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• v.45 no.4
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• pp.285-290
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• 2018

This study was aimed to evaluate the possibility of application to the KS A ISO 2859-1 Easy test, an international standards sampling inspection, to replace a sampling method of the current grading standard of chicken meats for the first time. As a result of screening capability to check for defective products, the current sampling was 0.61 and the KS A ISO 2859-1 Normal test was 0.70, suggesting that the latter inspection method was more accurate. If the KS A ISO 2859-1 conversion principle is applied, 40,530 won per day is saved for a 50-lot inspection. The current sampling and the KS A ISO 2859-1 Easy test did not exceed the reject limit for the number of defective products to satisfy the grade $1^+$ on chicken carcass size numbers 12, 9 and 8. Freshness was not significantly different between the current sampling and the KS A ISO 2859-1 Easy test. It is expected that using the KS A ISO 2859-1 Easy test with a smaller sample volume will have the same level of quality evaluation as the current sampling method while reducing costs.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.22 no.3
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• pp.55-71
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• 2019

The purpose of this study is to propose an evaluation method to assess green environments of streetscapes to improve urban street green spaces in Jeonju City. Through a rapid assessment of urban street green spaces, we suggest an objective basis for expanding street green space as well as for adopting sustainable maintenance and improvement measures. We choose 12 sections of streetscapes (roads and sidewalks) to investigate existing street conditions which have more than four lanes and function as major road axes. Six large roads and six medium roads of Jeonju City center area are investigated as pilot assessment study sites. Site inventory checklists consist of environmental characteristics of streetscape, street tree status, and planting condition evaluation. Environmental characteristics of streetscapes are composed of physical and neighborhood factors. For instance, items for physical factors are types and width of road/sidewalks, paving materials, tree protection materials, and green strip. And surrounding landuse is a neighborhood factor. Assessment items for street tree status are street plant names (tree/shrubs/ground cover), size, and planting intervals. Planting condition evaluation items are tree shape, damage, canopy density, and planting types with existence of adjacent green space. Evaluation results are classified into three levels such as A(maintain or repair), B(greening enhancement), and C(structural improvement). In case of grade A, streetscapes have enough sidewalk width for maintaining green strip and a multi-layered planting(in large road only) with fairly good growing conditions of street trees. For grade B and C, streetscapes have a moderate level of sidewalk width with a single street tree planting. In addition, street tree growing conditions are appeared poor so that green enhancement or maintenance measures are needed. For median, only grade B and C are found as its planting growing foundations are very limited in space. As a result, acquiring enough sidewalk space is essential to enhance ecological quality of urban street green. Especially, it is necessary to have green strip with reasonable widths for plant growing conditions in sidewalks. In addition, we need to consider native species with multi-layer plant compositions while designing street green.

• Educational Technology International
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• v.6 no.2
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• pp.23-41
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• 2005

One of the main factors that determine the quality of instruction is the teaching ability of the instructor administering the class. To evaluate teaching ability, methods such as peer review, student feedback, and teaching portfolio can be used. Among these, because feedback from the students is directly associated with how well the students feel they have learned, it is essential to improving instruction and teaching ability. The principal aim of instruction evaluation lies in the evaluation of instructor's qualification and the improvement of instruction quality by enhancing professionalism. However, the mandatory instruction evaluations currently being carried out at the term's end in universities today have limitations in improving instruction in terms of its evaluation items and times. To improve the quality of instruction and raise teaching abilities, instruction evaluations should not stop at simply being carried out but also be utilized as useful data for students and teachers. In other words, they need to be used to develop teaching and improve instruction for teachers, and consequently, should also exert a positive influence on students' scholastic achievements and learning ability. The most important thing in evaluation is the acquisition of accurate information and how to utilize it to improve instruction. The online instruction diagnosis item pool is a more realistic feedback device developed to improve instruction quality. The instruction diagnosis item pool is a cafeteria-like collection of hundreds of feedback questions provided to enable instructors to diagnose their instruction through self-diagnosis or students' feedback, and the instructors can directly select the questions that are appropriate to the special characteristics of their instruction voluntarily make use of them whenever they are needed. The current study, in order to find out if the online instruction diagnosis item pool is truly useful in reforming and improving instruction, conducted pre and post tests using 256 undergraduate students from Y university as subjects, and studied the effects of student feedback on instructions. Results showed that the implementation of instruction diagnosis improved students' responsibility regarding their classes, and students had positive opinions regarding the usefulness of online instruction diagnosis item pool in instruction evaluation. Also, after instruction diagnosis, analyzing the results through consultations with education development specialists, and then establishing and carrying out instruction reforms were shown to be more effective. In order to utilize the instruction diagnostic system more effectively, from planning the execution of instruction diagnosis to analyzing the results, consulting, and deciding how those results could be utilized to instruction, a systematic strategy is needed. In addition, professors and students need to develop a more active sense of ownership in order to elevate the level of their instruction.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.15 no.4
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• pp.369-380
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• 2017

In order to manage the uncertainty about the evaluation and analysis of the human intrusion scenario of the Gyeongju Low and Intermediate Level Radioactive Waste(LILW) disposal facility, the calculation result by the GENII code was assessed using the RESRAD code, which was developed to evaluate the radiation effects of contaminated soil. The post-drilling scenario was selected as a human intrusion scenario into the near-surface disposal facility to analyze the uncertainty of the modeling by identifying any limitations in the simulation of each code and comparing the evaluation results under the same input data conditions. The results revealed a difference in the migration of some nuclides between the codes, but confirmed that the dose trends at the end of the post-closure control period were similar for all exposure pathways. Based on the results of the dose evaluation predicted by RESRAD, sensitivity analysis on the input factors was performed and major input factors were derived. The uncertainty of the modeling results and the input factors were analyzed and the reliability of the safety evaluation results was confirmed. The results of this study can be applied to the implementation 'Safety Case Program' for the Gyeongju LILW disposal facility.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.768-777
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• 2017

The efforts to improve river levee maintenance technologies have accelerated globally in a bid to deal with the flood damage resulting from the changes to the climate and flood events. This paper, in line with such tendency, proposes an evaluation system of a river levee safety map to maintain the river levee in an efficient manner. The concept of a river levee safety map is aimed at maximizing the maintenance efficiency for a manager to indicate the safety index, including the current river levee sliding, piping, and visual inspection on a GIS map. To develop such an evaluation system, a safety index covering the sliding, piping, and visual inspection are designated through the data and document examination and the rational guideline to classify each index into three grades, A, B, and C, is proposed. Based on the guideline proposed, the sliding and piping characteristics in terms of safety depending on the change to the flood water level duration time at the test section (Nam river) were evaluated by numerical analysis. As a result, both the protected landside and riverside satisfied the requirements for Grade A in terms of sliding, and when it comes to piping, the grade declined to C because the flood water level duration time increased at R2. As a planning study to propose a river levee safety map evaluation system, a further advanced study, standardization of the river levee data, and improvement of the existing system and laws are required.