• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.1
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• pp.99-106
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• 2023

Recently, many studies on crop yield prediction using deep learning technology have been conducted. These algorithms have difficulty constructing a linear map between input data sets and crop prediction results. Furthermore, implementation of these algorithms positively depends on the rate of acquired attributes. Deep reinforcement learning can overcome these limitations. This paper analyzes the performance of DQN, Double DQN and Dueling DQN to improve crop yield prediction. The DQN algorithm retains the overestimation problem. Whereas, Double DQN declines the over-estimations and leads to getting better results. The proposed models achieves these by reducing the falsehood and increasing the prediction exactness.

• Journal of The Korean Association For Science Education
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• v.40 no.5
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• pp.473-483
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• 2020

The purpose of this study was to analyze the characteristics of students' academic achievement of middle school science curriculum achievement standards in the 2009 revised national curriculum and to generate implications for curriculum improvement. Based on the results of the 2015-2018 National Assessment of Educational Achievement (NAEA), we analyzed middle school students' mastery of 84 curriculum achievement standards. In the analysis, we used representative item information by achievement level and correct answer rate and checked the validity of the determination of mastery. According to the results of the analysis, 15 of the 84 achievement standards could not determine the degree of achievement. In science, many achievement standards could be mastered only by above-average group students. By achievement level, there were six achievement standards that advanced achievement-level students did not achieve, 38 achievement standards judged to represent mastery by advanced achievement-level students, 23 achievement standards judged to represent mastery by proficient achievement-level students, and two achievement standards judged to represent mastery by basic achievement-level students. By content area, the number of achievement standards corresponding to advanced and proficient levels was similar in the areas of motion and energy and earth and space domains. In the material and life domains, there were more achievement standards corresponding to advanced levels. Accordingly, it is necessary to reinforce customized teaching and learning activities in relation to achievement standards that were under-achieved.

• The Korean Journal of Nuclear Medicine
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• v.37 no.5
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• pp.331-335
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• 2003

Purpose: Accurate assessment of the lesion after treatment of patients with bone lymphoma is difficult. In this patient who demonstrated complete remission after chemotherapy, the regions of fluorine-18 fluorodeoxyglucose $(^{18}FFDG)PET$ uptake diminished more rapidly fellowing therapy, indicating a complete response at much earlier stage than did Magnetic Resonance Imaging (MRI) or CT based findings. With the conventional methods, such as MRI and CT, It was difficult to assess whether the residual tumor tissue was viable or not. Decision to complete response is very important in patients with lymphoma to plan the further treatment. We experienced a patient with primary lymphoma of bone who revealed complete response to chemotherapy on $^{18}FFDGPET$ while CT showed persistent destructive bone lesion. Thus, $^{18}FFDGPET$ study after therapy may be superior to CT in the evaluation of response to treatment in primary lymphoma of bone.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.269-274
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• 2004

The marine electronic system for safe navigation such as ECDIS has been contributing to increase the safety of navigation, decreasing the mariner's load of navigation. The ECDIS should be developed and approved by international standard of IMO for performance standard and IEC for type-approval method and required results. However, these standards have some ambiguities for us not to directly adopt them for real approval system, so we should analyze them for more clear meaning and prepare our own detail standard for type-approval system. The first thing to do for the goal of this research was to analyze the standard in detail and make ambiguity be cleared in our own standards, considering each test item in view of test methodology. For the result of analysis we could develop more evident and detail type-approval standard for each test item with test technology needed. Especially, we developed the colour differentiation test process of ECDIS monitor, which include the colour differentiation formula derived from CIE colour scheme. Several test items require sensor informations of navigation equipment compatible with IEC 61162. We also developed the signal simulator for general messages of IEC 61162 that must be provided. Additionally, the type-approval processes and standards for Back-up arrangement and RCDS mode were developed.

• Journal of Mushroom
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• v.3 no.3
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• pp.100-104
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• 2005

We investigated mineral difference from mushroom Phellinus linteus and Phellinus baumii on mulberry, oak and elm. ICP test, The major mineral components were K, Ca, and Fe, while Mg, Na, P, Cr, Mn, Cu and Zn were determined as micro mineral components. In case of P.linetus and P.baumii the component of K was shown as 699.0mg/100g and 630mg/100g, in oak, 340.7mg/100g and 314.6mg/100g in elm, and 311.6mg/100g and 311.6mg/100g in mulberry respectively. In Ca, mulberry fruiting body were shown about 2 times highest and expecially in case of Na was oak fruiting body were shown as 10 times highest as against the others sample groups. In micro mineral components, Zn component was shown very diffeence about sample groups. We concluded that the highest mineral component of K was shown in mushroom cultivated on oak of both P.linetus and P.baumii. As a results, mineral component has showed very difference on cultivated to timber. According to the results of mineral component we concluded that Phellinus linteus and Phellinus baumii has mineral component different depending on timber.

• Journal of Energy Engineering
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• v.22 no.2
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• pp.128-135
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• 2013

In order to estimate the combustion characteristics and the gas interchangeability for natural gas with various compositions per each production area, equivalent gas are using to replace natural gas. It is known that an equivalent gas has the same the heating value, the compression factor, the relative density, CO emission and the burning velocity as the original natural gas. However, it is not reported that the flame shape and thermal efficiency and NOx emission by real gas appliance. In this study, equivalent gas was examined the validation to replace natural gas. The CO emission the burning velocity and the flame temperature were reconfirmed, and the flame shape, the NOx emission and the thermal efficiency were numerically and experimentally investigated. As results, there was not a large difference between natural gas and equivalent gas. This result demonstrated that there was no problem using equivalent gas to replace natural gas.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.7
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• pp.75-83
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• 2007

IEC code based decision nile have been widely applied to detect incipient faults in power transformers. However, this method has a drawback to achieve the diagnosis with accuracy without experienced experts. In order to resolve this problem, we propose an artificial diagnosis algorithm to detect faults of power transformers using Self-Organizing Feature Map(SOM). The proposed method has two stages such as model construction and diagnostic procedure. First, faulty model is constructed by feature maps obtained by unsupervised learning for training data. And then, diagnosis is performed by compare feature map with it obtained for test data. Also the proposed method usぉms the possibility and degree of aging as well as the fault occurred in transformer by clustering and distance measure schemes. To demonstrate the validity of proposed method, various experiments are unformed and their results are presented.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.923-926
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• 2008

Currently more high flow and high performance concrete is used for construction of buildings in the world. However, when high flow and high performance concrete put high performance water reducing agent in quantity to improve flow, it has a negative effect on concrete structures since segregation arises from it though flow will be improved. There are naked-eye observation, coarse aggregate washing test, L Flow test for permeation among reinforcing rods and measurement of viscosity to judge concrete segregation resistance. However, it is difficult to apply them to practical affairs since they are very complicated and troublesome. Therefore, the study analyzed EIS dividing slump flow value into slump value, how to valuate concrete segregation resistance more easily, on the basis of the existing reference materials to propose EIS. As the results, in the event of high flow concrete, it is desirable that EIS value is prescribed to be less than 2.5 at the time of managing segregation. Also, at the time of prescribing EIS with performance, it is judged that it is desirable to manage segregation as less than 2.2 (Grade 1), 2.2$\sim$2.4 (Grade 2) and more than 2.6 (Grade 3).

• Journal of Dental Rehabilitation and Applied Science
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• v.33 no.3
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• pp.216-222
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• 2017

Intellectual disability is an imperfect disorder in which mental development is permanently retarded and development of intellectual ability is inadequate. Having intellectual disabilities makes it difficult to handle their own work and adapt to social life. For this reason, it is difficult to hygienically manage the patient's oral condition, multiple caries are easily observed, and the periodontal disease incidence rate is high. The patient in this case is a 33-year-old female with a mental retardation first grade who had a problem with meals. In first visit, Patients had decreased occlusal vertical dimension and posterior bite collapse due to periodontitis and multiple caries. This case reports a satisfactory functional and esthetic results by reconstructing occlusion using partial removable dental prosthesis.

• School Mathematics
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• v.12 no.3
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• pp.371-388
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• 2010

The goals of this study are to inquire middle school students' understanding about prime number and to propose pedagogical implications for school mathematics. Written questionnaire were given to 198 Korean seventh graders who had just finished learning about prime number and prime factorization and then 20 students participated in individual interviews for member checks. In defining prime and composite numbers, the students focused on distinguishing one from another by numbering of factors of agiven natural number. However, they hardly recognize the mathematical connection between prime and composite numbers related on the multiplicative structure of natural number. This study suggests that it is needed to emphasize the conceptual relationship between divisibility and prime decomposition and the prime numbers as the multiplicative building blocks of natural numbers based on the Fundamental Theorem of Arithmetic.