• The Journal of the Korea Contents Association
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• v.8 no.11
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• pp.182-188
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• 2008

The MLC(multi leaf collimator) in charge of important role in radiation therapy field recently have been exchanging from shielding block into it rapidly, owing to being convenient. However, MLC can be occurred the leakage dose of inter_leaves and the error of algorithm in imput and output from digital signal. We compared the difference of imput method to MLC made by Varian Cop. with the error and effective field induced by MLC shaper and film scanner based on XimaVision value as using MLC layer of various shapes. According to comparing standard value with them to basic MLC layer (test1-5), MLC shaper was $0{\sim}0.29cm$, $0.23{\sim}3.59cm^2$ and film scanner was $0{\sim}0.78cm$, $0.24{\sim}3.89cm^2$. At the MLC layer to be applied in clinic, MLC shaper was $0{\sim}0.54cm$, $0.04{\sim}1.68cm^2$ and film scanner was $0{\sim}0.78cm$, $0.24{\sim}3.89cm^2$. The more distance and field from axis of central line increase, the more bigger the error value increases. There is a few mm error from standard point at the process which imput various information to apply MLC in clinic. and effective field did not have variation of monitor unit and dose owing to being a few cm2 error against real field. But there are some problem to shield critical organs because some part of target volume induced by the movement of organs can be not included, therefore we have to pay attention on the process to imput MLC layer

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.4
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• pp.57-64
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• 2022

Chloride, which is one of the main deterioration factors in reinforced concrete structures, can degrade the performance of the structure due to chloride-induced corrosion of steel. Chloride content at steel depth or the rate of chloride penetration is necessary to determine deterioration of reinforced concrete or to calculate initiation time of steel corrosion caused by chloride attack. Chlorides in concrete are generally identified with typical two methods including chloride profiling using potentiometric titration method and discoloration method using AgNO₃ solution. The former is advantageous to estimate chloride penetration rate (diffusion coefficient in general) with measured chloride contents directly, but it is laborious. In the case of latter, while the result is obtained easily with the range of discoloration, the error may occur depending on workmanship when the depth of chloride ingress is measured. This study shows that chloride penetrated depth is evaluated with the results obtained from discoloration method through image analysis, thereby the error is minimized by workmanship. In addition, the effect of micro-crack in concrete is studied on chloride penetration. In conclusion, the depth of chloride penetration was quantified with image analysis and as it was confirmed that chlorides can rapidly penetrate through micro-cracks, caution is especially required for cracks in concrete structure.

• Communications of Mathematical Education
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• v.36 no.3
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• pp.335-353
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• 2022

The purpose of this study is to identify the characteristics and types of errors in the conceptual image of Korean language learners according to the types of terms in mathematics that are the basis for solving mathematical word problems, and to prepare basic data for effective teaching and learning methods in solving the word problems of Korean language learners. To do this, a case study was conducted targeting four Korean language learners to analyze the specific conceptual images of terms registered in curriculum and terms that were not registered in curriculum but used in textbooks. As a result of this study, first, it is necessary to guide Korean language learners by using sufficient visualization material so that they can form appropriate conceptual definitions for terms in school mathematics. Second, it is necessary to understand the specific relationship between the language used in the home of Korean language learners and the conceptual image of terms in school mathematics. Third, it is necessary to pay attention to the passive term, which has difficulty in understanding the meaning rather than the active term. Fourth, even for Korean language learners who do not have difficulties in daily communication, it is necessary to instruct them on everyday language that are not registered in the curriculum but used in math textbooks. Fifth, terms in school mathematics should be taught in consideration of the types of errors that reflect the linguistic characteristics of Korean language learners shown in the explanation of terms. This recognition is expected to be helpful in teaching word problem solving for Korean language learners with different linguistic backgrounds.

• The Journal of the Korea Contents Association
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• v.20 no.3
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• pp.298-308
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• 2020

This study was designed to verify reliability and feasibility by analyzing elderly drivers' ability test tools for older drivers aged 65 or older, which were improved in 2018 and are currently being conducted by the Korea Highway Traffic Authority. Only those aged 65 or older who voluntarily applied to the elderly driving ability evaluation system implemented by the Seoul branch of the Korea Highway Traffic Authority. The research was conducted for about 50 days until Aug. 31, 2018, starting with the registration and inspection of the first study subjects. The analysis performed a correlation analysis with existing tools and cognitive testing tools (MMSE_K) to determine their feasibility and reliability as an improved tool in 2018. As a result, the first, the speed distance, time-space memory, and dispersionism of each sub-component of the old version showed statistically significant static correlation with the sub-factor of the current version. Persistence, on the other hand, was not statistically significant to the current version. The limitations of this study were as follows. Most of the people in the study were highly educated and residents in the metropolitan area. Therefore, it is likely that the results of MSE_K, which checks cognitive and judgment skills, have been upgraded. Also, cognitive tools that are measured by computers are likely to have real measurement errors for generations who are not familiar with computers. Therefore, it is expected that improvement and development of tools for improving the limit points at the site and assessing actual operation capability will be required.

• Therapeutic Science for Rehabilitation
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• v.8 no.2
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• pp.67-78
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• 2019

Objective : The purpose of this study was to investigate the effect of hand tapping on the accuracy and the fluency of speech production in children with speech sound disorder(SSD) and their typically developing peers(TD). Methods : The study subjects were 15 SSD children and 15 TD children aged 4, 5, and 6 years of age. Subjects were asked to give a picture name without hand tapping in the first experimental condition, and with hand tapping in the second experiment condition. Results : The results showed that hand tapping significantly increased disfluency in TD, whereas in SSD. it did not affect the accuracy or fluency of speech production. In addition, TD demonstrated a significant positive correlation with the changes of accuracy and disfluency due to hand tapping, whereas SSD had no correlation. Conclusion : We discussed the possibility that hand tapping could serve as an obstacle distracting attention from SSD and TD, acting as a motor gesture to facilitate phonological processing when facing the difficulty in lexical retrieval for SSD.

• Solar Energy
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• v.10 no.3
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• pp.13-18
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• 1990

When nonuniform thermal boundary conditions are imposed on the surface of a circular cylinder in crossflow, the heat transfer characteristics can be quite different compared to what is found for isothermal or constant heat flux boundary conditions. In the present analysis, two kinds of nonuniform boundary conditions along the circumference of the cylinder are considered in a uniform stream of air: step changes and linear profiles. Step changes in temperature can arise on the surface of an external, cylindrical, solar central receiver. As the working fluid(water) flows through the vertical tubes that ring the circumference of Solar One(a solar central receiver in Barstow, California), the solar flux on the receiver heats the water from a liquid to a superheated state. In this process, portions of the receiver panels, and thus portions of the circumference of the cylinder, function as a preheater, boiler, or superheater. Hence the surface temperature can vary significantly around the cylinder. Common engineering practice has been to use an average wall temperature with an isothermal cylinder heat transfer coefficient when estimating the convective loss in these kinds of situations.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.8
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• pp.66-74
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• 2014

Recently a variety of study of Korean parsing system is carried out by many software engineers and linguists. The parsing system mainly uses the method of machine learning or symbol processing paradigm. But the parsing system using machine learning has long training time because the data of Korean sentence is very big. And the system shows the limited recognition rate because the data has self error. In this thesis we design system using feature module which can reduce training time and analyze the recognized rate each the number of training sentences and repetition times. The designed system uses the separated modules and sorted table for binary search. We use the refined 36,090 sentences which is extracted by Sejong Corpus. The training time is decreased about three hours and the comparison of recognized rate is the highest as 84.54% when 10,000 sentences is trained 50 times. When all training sentence(32,481) is trained 10 times, the recognition rate is 82.99%. As a result it is more efficient that the system is used the refined data and is repeated the training until it became the steady state.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.3
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• pp.7-12
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• 2014

The data forwarding transmission is an important function of the relay in cooperative communication in wireless communication systems. However, additional relay cause the waste of power consumption and cost. Therefore, in this paper, we consider how to use the user mobile devices in stead of relays to deal with this problem. In this paper, we proposed the protocol that divide each relay into two states of idle and non-idle. The receiver has two functions of base station and user mobile device. In this case, it is possible that no additional cost, and improve the spectral efficiency and network capacity. We verified BER performance for the proposed protocol over Rayleigh fading through Monte-Carlo simulation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.3
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• pp.585-590
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• 2012

Coronary Intervention treatment has become the core that is the test of cardiac catheterization to conduct treatment with Coronary Arteriography. Operators must be careful in Coronary Intervention treatment because the stent is inserted into the point of narrowing of blood vessel. So, the operator must correctly recognize the path of blood vessel to deal with the problems which are damages and ruptures of blood vessel, and there would be some errors of finding the path of blood vessel by bad qualify of the image. Therefore in this paper, median filtering is conducted by preprocessing to evaluate the performance of the effect of noise of the image that affects quality of the image and Fuzzy Edge Extraction Techniques is tested by using Soble Edge Extraction Techniques to compare the performance with The Fuzzy Edge Extraction Techniques. In result, the performance, removing the noise and extracting the signal of Fuzzy Edge Extraction Techniques using median filtering, demonstrates the superiority.

• Childhood Kidney Diseases
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• v.11 no.2
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• pp.152-160
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• 2007

Twenty-six renal allograft biopsies which showed acute rejection and had renal capsule and medulla in the same specimen were selected in order to compare the severity of acute rejection between superficial cortex, deep cortex and medulla. Disregarding the mid cortical region, the superficial cortex was considered as being one-third of the distance from the renal capsule to the medulla and the deep cortex as being that one-third of the cortex which was adjacent to the medulla. Using semiquantitative histologic analysis the following parameters were compared in superficial cortex, deep cortex, and medulla: interstitial inflammation, edema, tubulitis, and acute tubulointerstitial rejection grade. Also, the presence of lymphocyte activation and polymorphonuclear leukocytes was evaluated. Significantly greater histologic changes of acute rejection were found in the deep cortex vs. supeficial cortex for the following parameters: interstitial inflammation(P=0.013), edema (P=0.023) and tubulointerstitial rejection grade(P=0.016). These findings support the view that biopsies in which deep cortex is not included may result in underestimation of the severity of renal allograft rejection.