• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.11C
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• pp.851-859
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• 2008

This paper investigates the effect a guard period (GP) in the form of a cyclic prefix for asynchronous multicarrier-code division multiple access (MC-CDMA) systems. At first, we analyze the performance of asynchronous MC-CDMA systems with a GP, which results in closed-form bit error rate (BER) performance. Furthermore, it confirms that the frequency diversity of MC-CDMA systems is identical to the path diversity. The analytical approach proposed here is extended to the case without a GP. The derived analytical results show that a GP is required for MC-CDMA systems in order to mitigate not only the effect of intersymbol interference (ISI) and intercarrier interference (ICI) but also the desired signal power degradation. In addition, the accuracy of the proposed analysis is verified by simulations.

• Journal of the Korean School Mathematics Society
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• v.21 no.4
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• pp.401-418
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• 2018

The current geometric and vector textbooks focus on the mechanical activities of finding focus, corner, etc. through elliptic equations. In this paper, we propose a process in which analogy and analytical methods are used in reversible activities of focusing from a given elliptic graph without a coordinate plane. The exploratory tool was used as Geogebra. At first, students tried to find the focus of the ellipse by randomly constructing the major a is and the minor a is in the given ellipse. However, we have experienced a method of constructing the circle of symmetry and analyzed this principle and deduced it to the ellipse. As a result, we could construct the center, long a is and short a is of the ellipse. Then, using the analytical method, the focus formula was recognized as the Pythagorean theorem, and the ellipse's focus was constructed by using the original drawing. Therefore, it is confirmed that analogy and analytical method can positively affect the elliptical focus.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.11
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• pp.2295-2303
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• 2009

Underwater acoustic(UWA) communication has multipath error because of reflection by sea-level and sea-bottom. The multipath of UWA channel causes signal distortion and error floor. In this paper, we proposed the compensation method of multipath effect using the impulse response of the UWA channel and then analysis the performance of channel coding such as LDPC code, concatenate code. Also we analysed the time-delay errors and estimated amplitude errors of estimated channel information and its affection on the performance. As shown in simulation results, the performance of proposed compensation method is better than the performance of conventional method.

• Journal of the Korea Computer Graphics Society
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• v.27 no.4
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• pp.1-9
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• 2021

Segmenting the compartments of neurons, such as axons, dendrites, and cell bodies, is helpful in the analysis of neurological phenomena. Recently, there have been several studies to segment the compartments through deep learning. However, this approach has the potential to include errors in the results due to noise in data and differences between training data and actual data. Therefore, in order to use these for actual analysis, it is essential to proofread the results. The proofreading process requires a lot of effort and time because an expert must perform it manually. We propose an interactive neuron structure proofreading method that can more easily correct errors in the segmentation results of a deep learning. This method proofread the neuron structure based on the characteristics of the neuron with structural consistency, so that a high-accuracy proofreading result can be obtained with less interaction.

• Journal of Korean Society of Forest Science
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• v.102 no.1
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• pp.38-58
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• 2013

The existence of endemism in many parts of the world is an important factor for conservationists. Conservation can only be carried out under national legislation, and national endemics, which have very limited ranges, fully depend on the effort and success of conservation. A total of 523 vascular plant taxa were listed in the latest national checklist by Ministry of Environment in 2005, while the 'Creation and Furtherance of Arboretums Act' including a national endemic list (appendix 4-1) was established by Korea Forest Service and was legislated as a law in late 2011. This legislation by Korea Forest Service on endemism of Korean vascular plants have required much attention because of discrepancies of nomenclature, taxonomic bias and inflation. Examining data for both lists proposed by Ministry of Environment and Korea Forest Service, of the total of 360 legislated taxa, around 286 taxa are shared with the list of Ministry of Environment, of which about 80% have been found as common taxa. Around 67(18.7%) are typographic errors, and 14 taxa (3.9%) are recorded as illegitimate and invalidly published names. Through this analysis 12 taxa (3.4%) were found in China as well as in Korea and these are thought to be non Korean endemic taxa. Taken together, the legislated list displayed 1/4 (24.9%) errors out of the total list. Only 59 taxa (16.5%) are identified as national endemic species. The remainder are either unresolved candidates (73 taxa, 20.4%) or synonyms (196 taxa, 54.7%) status. It must be noted, that the concept of endemism very much depends on the knowledge of the species concept, taxonomic bias and geographical range of a species. Also, the most major nomenclatural problem tend to be more stable if the information on database about Korea Plant Name, which is managed by Korea National Arboretum are well updated year to year. These exaggerated numbers underscore the urgency for regional conservation planning and implementing effective strategies to preserve these real endemic taxa into the future.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.2
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• pp.83-92
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• 2009

As the innovative internet technologies and multimedia are being rapidly developed, malicious codes are a remarkable new growth part and supplied by various channel. This project presents a classification methodology for malicious codes in Windows OS (Operating System) environment, develops a test classification system. Thousands of malicious codes are brought in every day. In a result, classification system is needed to analyzers for supporting information which newly brought malicious codes are a new species or a variety. This system provides the similarity for analyzers to judge how much a new species or a variety is different to the known malicious code. It provides to save time and effort, to less a faulty analysis. This research includes the design of classification system and test system. We classify the malicious codes to 9 groups and then 9 groups divide the clusters according to the each property.

• The Journal of Korean Society for Radiation Therapy
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• v.32
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• pp.73-83
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• 2020

Purpose: The purpose of this study is to confirm the matching of the electron density between tissue and gas due to variation of abdominal gas volume in MRgART (Magnetic Resonance-guided Adaptive Radiation Therapy) for pancreatic cancer patients, and to confirm the effect on the dose change and treatment time. Materials and Methods: We compared the PTV and OAR doses of the initial plan and the AGC(Abdominal gas correction) plans to one pancreatic cancer patient who treated with MRgART using the ViewRay MRIdian System (Viewray, USA) at this clinic. In the 4fx AGC plans, Beam ON(%) according to the patient's motion error was checked to confirm the effect of abdominal gas volume on treatment time. Results: Comparing the Initial plan with the average value of AGC plan, the dose difference was -7 to 0.1% in OAR and decreased by 0.16% on average, and in PTV, the dose decreased by 4.5% to 5.5% and decreased by 5.1% on average. In Adaptive treatment, as the abdominal gas volume increased, the Beam ON(%) decreased. Conclusion: Abdominal gas volume variation causes dose change due to inaccurate electron density matching between tissue and gas. In addition, if the abdominal gas volume increases, the Beam ON(%) decreases, and the treatment time may increase due to the motion error of the patient. Therefore, in MRgART, it is necessary to check the electron density matching and minimize the variability of the abdominal gas.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.2
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• pp.432-438
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• 2011

This paper describes an analysis of optimal design conditions of multi-mode LDPC(low density parity check) decoder which supports three block lengths (648, 1296, 1944) and four code rates (1/2, 2/3, 3/4, 5/6) for IEEE 802.11n WLAN system. A fixed-point model of LDPC decoder, which adopts min-sum algorithm and layered decoding scheme, is implemented using Matlab. From fixed-point simulation results for various bit-width parameters such as internal bit-width, integer/fractional part bit-widths, optimal design conditions and decoding performance of LDPC decoder are analyzed.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.478-481
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• 2015

모바일 기기의 특성 중 하나인 제한된 전력은 중요한 문제로 다뤄지고 있다. 이러한 전력 문제를 해소하기 위해 다양한 모바일 저전력화 연구가 진행되고 있다. 이러한 연구들 중 전력 측정이 정확하지 않으면 저전력화 연구에 치명적인 오류를 가져올 수 있기 때문에 정확한 전력 측정은 다른 연구들의 근본이 된다고 할 수 있다. 이를 위해 포터블 전력 측정 장비(Portable Power Measurement and Analysis tools, PPAM)를 개발하였다. 그러나 포터블 전력 측정 장비는 높은 샘플링 주파수로 인한 방대한 양의 데이터를 텍스트로 출력한다. 이 데이터를 보다 효과적으로 분석하기 위해 본 논문에서는 데이터의 간소화와 시각화 등의 2가지 요구사항을 도출하였으며, 이를 충족하는 모바일 소프트웨어의 상태별 전력 소모 분석을 위한 뷰어 개발을 하였다. 이 뷰어를 사용함으로써 연구자는 소모 전력 데이터를 보다 직관적이며, 효율적으로 분석이 가능하다. 향후 이 뷰어는 포터블 전력 측정 장비와 함께 소프트웨어의 저전력화 연구에 도움이 될 것이다.

• Journal of the Korean Society of Earth Science Education
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• v.17 no.2
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• pp.86-101
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• 2024

The purpose of this study is to provide basic data on the importance of accurate scientific communication and the current status of popular astronomy based on science articles that occurred during the so-called Super Blue Moon astronomical phenomenon in August 2023. To this end, the subjects were divided into non-experts, quasi-experts, and experts based on the degree of knowledge of the astronomical universe to investigate the data interpretation ability of astronomical science information and to analyze the causes of errors in the interpretation process through in-depth interviews. We also investigated the favorability and reliability of research institutes that strive to provide scientific information and the media that strive to spread it and also investigated the changes in existing favorability and reliability when incorrect scientific information spreads, as in this case. Although there were differences in the interpretation of scientific information about the astronomical universe depending on the cognitive aspect, the influence of linguistic elements or literacy, which could be called communication, could not be ignored. In particular, it was confirmed that misconceptions inherent in the existing research subjects could be expressed, leading to errors in accurate information interpretation. In addition, after recognizing that errors were included in the spread of scientific information, the subjects' favorability toward research institutes and the media fell 12.30% and 17.58%, respectively, while reliability fell 19.40% for research institutes and 24.49% for media outlets. Regardless of the cause of the error, the importance of providing accurate scientific information is further emphasized, considering that the overall favorability and reliability of both research institutes and the media decline. In order for research institutes and media outlets to spread accurate scientific information about the astronomical universe based on the public's trust, it is necessary to establish a system that can accurately deliver error-free information generated by research institutes related to astronomical space to media or science communicators and to develop a system that quickly retrieves and corrects incorrect scientific information through continuous monitoring.