• Journal of Educational Research in Mathematics
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• v.24 no.4
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• pp.595-605
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• 2014

Infinite decimals have an infinite number of digits, chosen arbitrary and independently, to the right side of the decimal point. Since infinite decimals are ambiguous numbers impossible to write them down completely, the infinite decimal representation accompanies unavoidable opaqueness. This article focused the transparent aspect of infinite decimal representation with respect to the completeness axiom of real numbers. Long before the formalization of real number concept in $19^{th}$ century, many mathematicians were able to deal with real numbers relying on this transparency of infinite decimal representations. This analysis will contribute to overcome the double discontinuity caused by the different conceptualizations of real numbers in school and academic mathematics.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.217-217
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• 2020

인간 물이용 중심의 하천 관리로 하천에 인위적으로 설치되는 횡단구조물은 물의 흐름을 막아 수질환경을 악화시킬 뿐 아니라 하천의 연속성을 단절하여 생물의 이동을 차단하여 생태계에 악영향을 미친다. 이러한 인위적인 구조물로서 약 34000여개의 농업용 보와 약 16000여개로 추정되는 낙차공이 다수 존재하고 있다. 이러한 구조물은 유수에 의하여 하상으로 전달되는 유수에너지를 저감하기 위하여 다양한 형태의 하상보호공을 설치하여 하천횡단구조물을 보호하도록 되어있다. 그러나 하상보호공에 사용되는 기술 중 사석 및 돌망태와 같은 기술은 시공비용이 적고 빠른 시간에 시공 할 수 있지만 급격한 홍수에 쉽게 파괴 및 유실이 되는 단점이 있으며, 콘크리트 소재 공법은 세굴방지에 좋은 효과를 발휘하는 장점을 지니지만, 시간이 지남에 따라 마모/변형되거나 포락/유실되어 하상을 지속적으로 보호하지 못하게 되며 과도한 세굴은 구조물의 안전성에도 영향을 미친다고 할 수 있다. 최근 기후변화로 인하여 돌발호우 및 강우량의 증가로 돌변하는 하천환경에 대한 적용기술은 미비한 실정이기 때문에, 많은 연구자들은 이에 대한 해결책을 찾기 위하여 자연친화적 생태복원 기술을 개발하고 있다. 본 연구에서는 바이오폴리머를 다층다공성 하상보호기술에 대하여 에너지 저감 효율, 고유속에서 한계 소류력, 소재 이탈 실험을 최대유량 10 ㎥/s, 유속 8m/s를 재현할 수 있는 실규모 하천실험장에서 진행하여 과학적인 안전성을 확인하였다.

• Journal of Advanced Navigation Technology
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• v.14 no.5
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• pp.648-654
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• 2010

In this paper, a navigation system was designed, and performance tested in order to confirm the safety improvement of the GNSS(Global Navigation Satellite System)-based AGV(Autonomous Guided Vehicle) which used only position information on of GNSS. We developed DR(Dead Reckoning) navigation system that involve the use of GNSS abnormal positoning error detection and GNSS signal outage. The test results show that GNSS positioning error is detection can be archived with an error of more than 0.15m. In addition, the DR driving position error is 1.5m for an 8s GNSS positioning service outage.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.464-464
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• 2016

기존의 고정보 설치에 따른 문제점으로 보 상류의 유속감소로 인한 유사나 오니의 퇴적으로 저류량의 감소, 홍수위 상승, 수질악화, 보 상 하류간 연속성의 단절 등의 개선을 위한 연직가동보에서의 수리특성을 분석하였다. 그에 따라 본 연구에서는 gate의 개도 높이를 조절함으로써 하상 퇴적물을 배출하고 수위와 유량을 조절할 수 있는 하단배출형 가동보를 길이 10 m, 폭 0.4 m, 높이 0.4 m의 가변경사식 수로에 다단식으로 배치하여 유량과 가동보 개도 높이에 따른 수리 특성을 분석하였다. 연직가동보의 개도에 따른 방류량의 수리특성으로 유량계수를 분석하고 그에 따른 보 상류에서 저류특성을 분석하였다. 유량과 연직가동보의 개도에 따른 수리특성으로 도수현상에 따른 수축계수, 도수길이, 도수높이를 분석하고 그에 따른 관계식을 제시하였다. 연직가동보 주변의 수리특성의 분석을 위한 차원해석을 실시하고 지배적인 무차원 변수를 도출하였다.

• Journal of the Korea Fashion and Costume Design Association
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• v.5 no.2
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• pp.47-55
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• 2003

This study was aimed at analyzing the woman costume presented in the korean modern novel by continuity, mixture, and discontinuity. For the costume analysis, the korean modern novel written from 1910 to 1945 were used. The results of this study were as follows: 1. Continuity: It doesn't mean discontinuity from the past but succession and development of the past, which explains about the costume culture for the period from 1910 to 1919. During this period, people tended to wear korean traditional costume in an effort to maintain their national identity. 2. Mixture: It means the effort to synthesize and develop past, present and future, which explains about the apparel for the period from 1920 to 1937. During this period, western culture was introduced much into korea to be established as part of our people's life. The new generation of women who studied abroad introduced the western costume throughout the cities, while the convenient western costume served to improve korean traditional costume. 3. Discontinuity: It means a conscious departure from the past as well as a critical reaction to the past, which explains about the costume culture for the period from 1938 to 1945. For this period, western costume was popular among new generation of women, while it was more diversified with increasing population wearing them. Many country men and women proceeded to wear the western costume.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.1
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• pp.107-114
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• 2011

Today the company adopts to use information management method at the network base such as internet, intranet and so on for the speed of business. Therefore the security of information asset protection and continuity of business within company in relation to this is directly connected to the credibility of the company. This paper secures continuity to the certified users using queuing model for the business interruption issue caused by DDoS attack which is faced seriously today. To do this I have reflected overloaded traffic improvement process to the queuing model through the analysis of related traffic information and packet when there occurs DDoS attack with worm/virus. And through experiment I compared and analyzed traffic loading improvement for general network equipment.

• Journal of Digital Convergence
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• v.13 no.10
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• pp.319-325
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• 2015

We proposed the blocking channel to reduce the performance decrease using the low correlation with cyclic delay scheme in LED-ID system. LED-ID is based on the visible light to transmit the data. However, It is occurred the block channel by structure or environment of indoor for light of straightness. LED-ID system is degraded the performance by the block channel as loss of data, and burst error. To solve the block channel, the proposed system is overcome the burst error by low correlation among data, which is able to obtain the maximize time diversity gain to improve the performance of BER by cyclic delay scheme. The BER performance is evaluated by computer simulation according to channel parameter. The simulation results shows that proposed system gives much better performance than conventional system and constant cyclic delay scheme system.

• Journal of KIISE:Information Networking
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• v.31 no.2
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• pp.146-157
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• 2004

In order to provide continuous QoS guaranteed to a mobile user, it is required to deploy some kind of mechanisms which reserves resources in advance at the locations to which the mobile user is expected to move. An important issue with regards to these mechanisms is to minimize the waste of resources caused by redundant reservations while keeping up the QoS guaranteed services to the user In this paper, we propose a wireless network domain structure which deploys a special cell, called “a gray cell”. The boundaries of two or more neighboring domains are surrounded by the gray cells, and the gray cells are supposed to belong to all of its neighboring domains. Based on this wireless domain structure, we propose a mechanism which completely removes the waste of redundant resource reservation in the wireless network domain while greatly reducing the risk of reservation disruption caused by inter-domain handover. Using simulation, it is shown that the proposed mechanism can deal with inter-domain handover as effectively as it does with intra-domain handover. It is also presented that the proposed mechanism outperforms existing mechanisms with respect to reservation disruption time and packet losses caused by handovers.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.11a
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• pp.191-192
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• 2019

The transport market has continued to change to provide services for each cargo. Currently, tank containers are widely used for the transport of liquids, and the tank container transportation market is continuously growing. Accordingly, the demand for handling for tank containers is also increasing. The purpose of this study is to suggest the improvement of transportation process and management method based on the case analysis of the current tank container transportation market. Therefore, this is paper suggests that an integrated system is needed to eliminate the period of information disconnection, secure information continuity, and improve the efficiency of managing dangerous goods.

• Korean Journal of Environmental Biology
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• v.38 no.4
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• pp.634-649
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• 2020

Recently, stream longitudinal connectivity has been a topic of investigation due to the frequent disconnections and the impact of aquatic ecosystems caused by the construction of small and medium-sized weirs and various artificial structures (fishways) directly influencing the stream ecosystem health. In this study, the international and domestic research trends of the longitudinal connectivity in aquatic ecosystems were evaluated and the applicability of fish-based longitudinal connectivity models used in developed countries was analyzed. For these purposes, we analyzed the current status of research on longitudinal connectivity and structural problems, fish monitoring methodology, monitoring approaches, longitudinal disconnectivity of fish movement, and biodiversity. In addition, we analyzed the current status and some technical limitations of physical habitat suitability evaluation, ecology-based water flow, eco-hydrological modeling for fish habitat connectivity, and the s/w program development for agent-based model. Numerous references, data, and various reports were examined to identify worldwide longitudinal stream connectivity evaluation models in European and non-European countries. The international approaches to longitudinal connectivity evaluations were categorized into five phases including 1) an approach integrating fish community and artificial structure surveys (two types input variables), 2) field monitoring approaches, 3) a stream geomorphological approach, 4) an artificial structure-based DB analytical approach, and 5) other approaches. the overall evaluation of survey methodologies and applicability for longitudinal stream connectivity suggested that the ICE model (Information sur la Continuite Ecologique) and the ICF model (Index de Connectivitat Fluvial), widely used in European countries, were appropriate for the application of longitudinal connectivity evaluations in Korean streams.