• KIPS Transactions on Software and Data Engineering
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• v.4 no.5
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• pp.231-240
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• 2015

Medical imagery require to protect the privacy with preserving the quality of the original contents. Therefore, reversible watermarking is a solution for this purpose. Previous researches have focused on general imagery and achieved high capacity and high quality. However, they raise a distortion over entire image and hence are not applicable to medical imagery which require to preserve the quality of the objects. In this paper, we propose a novel reversible watermarking for medical imagery, which preserve the quality of the objects and achieves high capacity. First, object and background region is segmented and then predicted error histogram-based reversible watermarking is applied for each region. For the efficient watermark embedding with small distortion in the object region, the embedding level at object region is set as low while the embedding level at background region is set as high. In experiments, the proposed algorithm is compared with the previous predicted error histogram-based algorithm in aspects of embedding capacity and perceptual quality. Results support that the proposed algorithm performs well over the previous algorithm.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.5
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• pp.45-53
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• 2007

To recover transmitted signal perfectly at DTV receiver, we have to acquire carrier frequency synchronization to compensate pilot signal which located in wrong position and rotated phase. Also, we need a symbol timing synchronization to compensate sampling timing error. Conventionally, to synchronize symbol timing, we use Gardner's scheme which used in multi-level signal. Gardner's scheme is well known for its sampling the timing error signal from every symbol and it makes easy to detect and keep timing sync in multi-path channel. In this paper, to discuss the problem when the received power level is out of range and we cannot get synchronization information. With this problem, we use 2 step procedures. First, we put a received signal power compensation block before Garder's timing error detector. Second, adaptive loop filter to get a fast synchronization information and averaging loop filter's output value to reduce the amount of jitter after synchronization in PLL(Phased Locked Loop) circuit which is used to get a carrier frequency synchronization and symbol timing synchronization. Using the averaging value, we can estimate offset. Based on offset changing ratio, we can adapt adaptive loop filter to carrier frequency and symbol timing synchronization circuit.

• Journal of the Korean Chemical Society
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• v.67 no.2
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• pp.106-115
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• 2023

The purpose of this study was to investigate the errors in science inquiry research reports written by students who won the encouragement award at the National Science Fair, and analyze the frequency of error types by school levels. The framework for analysis was constructed based on the table of contents of the students' science inquiry research reports, and the reports were analyzed for errors in six stages: Research question/hypothesis, prior research, experimental procedure, results, conclusions, and references. The study identified several types of errors at each stage, such as unreasonable research questions and wrong hypotheses in the research question/hypothesis stage, and limited considerations under certain conditions and selection of inappropriate experimental instruments in the experimental procedure stage. The study found that the frequency ratio of experimental procedure error was the highest across all school levels, and the order of errors varied by school level. Frequency ratio of error types of school level was: in the elementary school students' reports, errors were analyzed in the order of experimental procedure (36.88%), prior research (17.02%), conclusions (16.31%), research question/hypothesis (13.48%); In the middle school students' reports, experimental procedure (42.86%), conclusions (20.00%), prior research (14.28%), results (11.43%), research question/hypothesis (10.01%); In the high school students' reports, experimental procedure (45.16%), research question/ hypothesis (16.13%), conclusions (16.13%), and prior research (11.83%). The findings could be used to guide teachers in helping students conduct scientific inquiry research or write reports.

• The Mathematical Education
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• v.62 no.1
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• pp.35-55
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• 2023

The purpose of this study is to examine not only students' cognition in the mathematical error-finding activity of the concept of irrational numbers, but also the students' learning stance regarding the use of errors and a teacher's questioning strategies that lead to changes in the level of mathematical discourse. To this end, error-finding individual activities, group activities, and additional interviews were conducted with 133 middle school students, and students' cognition and the teacher's questioning strategies for changes in students' learning stance and levels of mathematical discourse were analyzed. As a result of the study, students' cognition focuses on the symbolic representation of irrational numbers and the representation of decimal numbers, and they recognize the existence of irrational numbers on a number line, but tend to have difficulty expressing a number line using figures. In addition, the importance of the teacher's leading and exploring questioning strategy was observed to promote changes in students' learning stance and levels of mathematical discourse. This study is valuable in that it specified the method of using errors in mathematics teaching and learning and elaborated the teacher's questioning strategies in finding mathematical errors.

• Nuclear Engineering and Technology
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• v.39 no.2
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• pp.133-142
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• 2007

The Electric Power Research Institute (EPRI) demonstrated a method for monitoring the performance of instrument channels in Topical Report (TR) 104965, 'On-Line Monitoring of Instrument Channel Performance.' This paper presents the results of several models originally developed by EPRI to monitor three nuclear plant sensor sets: Pressurizer Level, Reactor Protection System (RPS) Loop A, and Reactor Coolant System (RCS) Loop A Steam Generator (SG) Level. The sensor sets investigated include one redundant sensor model and two non-redundant sensor models. Each model employs an Auto-Associative Kernel Regression (AAKR) model architecture to predict correct sensor behavior. Performance of each of the developed models is evaluated using four metrics: accuracy, auto-sensitivity, cross-sensitivity, and newly developed Error Uncertainty Limit Monitoring (EULM) detectability. The uncertainty estimate for each model is also calculated through two methods: analytic formulas and Monte Carlo estimation. The uncertainty estimates are verified by calculating confidence interval coverages to assure that 95% of the measured data fall within the confidence intervals. The model performance evaluation identified the Pressurizer Level model as acceptable for on-line monitoring (OLM) implementation. The other two models, RPS Loop A and RCS Loop A SG Level, highlight two common problems that occur in model development and evaluation, namely faulty data and poor signal selection

• Research in Community and Public Health Nursing
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• v.28 no.4
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• pp.504-512
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• 2017

Purpose: This study aims to investigate the effects of atopic dermatitis on suicidal ideation, plans and attempts in young adult. Methods: Data are from the Sixth Korean National Health and Nutrition Examination Survey (KNHANES VI, 2013, 2015) in a sample of 2,983 respondents aged 19 to 39 years. Data were analyzed using Frequency, Percentage, $x^2$ test, Complex sample multivariate binary logistic regression analysis with SPSS version 18.0 software. Results: Firstly, factors affecting suicidal ideation are gender, education level, smoking, self-reported health status, asthma, depression and stress perception. Factors affecting suicidal plan are education level, self-reported health status, asthma and depression. Lastly, factors affecting suicidal attempt are gender, education level, smoking, self-reported health status, depression and stress perception. Compared to non-atopic group, the prevalence of suicidal ideation and plan of atopic group increased from odds ratio 2.14 to 2.48 and 1.90 to 2.50, respectively. Odds ratio for suicidal attempt was odds ratio 2.69 (10% error level). Conclusion: The results show that atopic dermatitis in young adult affects suicidal ideation, plans and attempts. Therefore, it is necessary to identify atopic patients who have suicidal thoughts and plans and develop an intervention program to prevent and manage suicide in young adult.

• Korean Journal of Child Studies
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• v.11 no.2
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• pp.5-23
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• 1990

The purpose of this study was to investigate the acquisition of number-word systems of young children. Specifically, the acquisition of Korean Number-Words(KNW) was compared with the acquisition of Chinese-derived Number-Words(CNW). The subjects included 120 children aged 2:5 to 5:11. The subjects oral counting using the two number word systems were audiotaped. Two coders transcribed the tapes. The data were analyzed by content analysis with descriptive statistics. The findings of this study showed that the acquisition of KNW began from around age two and the acquisition of CNW from around age three. From then, the acquisition of the two number-word systems was parallel. The acquisition of number-words began from the age of 2 years, increased slowly to the age of 4. and then increased rapidly after the age of 5. Although KNW were acquired earlier than CNW, at around the age of 5 years the acquisition of CNW surpassed the acquisition of KNW. The acquisition of number words consists of four developmental levels: Level I: beginning of acquisition of traditional KNW only Level II: beginning of acquisition of CNW with extension of KNW Level III: parallel extension of the two number-word systems Level IV: superior acquisition of CNW. The major error through all stages in the sequence of number words was the omission of one number-word. Younger children produced errors of omission of one, two or three number-words, whereas older children produced errors of nonstandard number-words and repetition.

• International Journal of Highway Engineering
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• v.14 no.6
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• pp.167-173
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• 2012

PURPOSES : This study is to develop speed correction factor for more realistic Level-of-Service(LOS) at multilane highway. METHODS : In this study, we compared speed difference the degree of speed reductions in actual multilane road conditions with speed reduction considering speed correction factor presented in highway capacity manual using statistical techniques. And also we presents new speed correction factor analyzing collected data at national highway No.1 (Goyang~Wolrung). RESULTS : The result of analyzing and comparing new suggested speed correction factor with speed correction factor in Korea Highway Capacity Manual (KHCM) shows RMSE (Root Mean Square Error) in new speed correction factor (RMSE 1.5) is much lower than existing speed correction factor (RMSE 13.4). New suggested speed correction can be used for analyzing Level-of-Service at multilane highway. And also we suggests improvements for analysis procedure in analyzing Level-of-Service at multilane highway CONCLUSIONS : As a result of comparing differences, we draw the causes that effect the differences in speed and suggest new speed correction factor that consider traffic volumes. It can be more rational because it uses speed correction factor which can consider more realistic traffic conditions, etc.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.9
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• pp.8-12
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• 2015

A Holographic data storage has some advantage of fast transmission, short access time and high storage capacity. However, it has several problems such as inter-symbol interference, inter-page interference and misalignment. Especially, for multi-level holographic data storage system, since one pixel contains more than 1bit, the system is more vulnerable to the error. In this paper, we propose a 3/4 modulation code which mitigate inter-symbol interference for 4-level holographic data storage.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.6
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• pp.1175-1180
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• 2009

Frame Aggregation is a promissing technology for improving MAC throughput in IEEE 802.11n. In IEEE 802.11n, two frame aggregation schemes, Aggregate MSDU (A-MSDU) and Aggregation MPDU (A-MPDU), are defined. In this paper, we analyze the performance the two-level frame aggregation scheme where A-MSDU and A-MPDU are combined. We develop the analytical model for the two-level frame aggregation scheme and present numerical results on the effect of bit error rate, aggregation size, and the number of nodes.