• The Transactions of the Korea Information Processing Society
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• v.4 no.7
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• pp.1781-1787
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• 1997

Future high speed networks are expected to use the Asynchronous Transfer Mode(ATM), which provides desired quality of service for the various traffic types(e.g., voice, video and data). Proper traffic control scheme helps ensure efficient and fair operation of networks. In this paper, we analyze various related traffic-control strategies and propose a new traffic control scheme and ATM control architecture with an integrated buffer management method and multi-thresholds in order to solve the problem of each class's cell loss ratio and cell delay in ATM networks. In addition, we evaluate the performance improvement of the proposed traffic control scheme through simulation. As shown in the result, the proposed traffic control scheme improves cell loss ratio in proportion to the buffer size.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.340-340
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• 2012

하천의 정밀한 유량관측은 수자원의 확보 및 효율적인 관리에 가장 기본적으로 수행되어야 하며 하천유량측정에 사용되는 기존의 방법으로는 유속계를 이용하여 평수기 때의 유속을 관측하는 방법과 홍수기시에 봉부자를 이용한 관측방법이 널리 이용되어 왔다. 하지만 기존의 관측방법은 경제성 및 효율성면에서 뒤떨어지기 때문에 새로운 측정방법을 개발하기 위한 연구가 활발히 진행되고 있다. 최근에는 한국수자원공사에서 개발된 전자파표면유속계를 이용하여 홍수유량을 관측하는 방법과 영상처리기술을 이용하여 관측하는 방법들이 다양하게 이용되고 있으며 본 연구에서는 표면영상유속계(SIV, Surface Image Velocimertry)를 이용하여 유량을 관측하였으며 동시에 전자파표면 유속계를 이용하여 관측된 값과 비교 분석하였다. 표면영상유속계(SIV, Surface Image Velocimertry)는 동영상 카메라를 이용하여 강이나 하천의 표면 유동을 촬영하고, 영상을 초당 30프레임으로 분석하여 변위를 구한다음 영상들의 시간 간격을 이용하여 최종적으로 표면 유속을 구하는 방법이다. 여기에 표면 유속과 평균 유속의 관계(노영신, 2005)를 이용하고, 하천 횡단면을 적용하여 유량을 산정하는 기법이다. SIV 기법을 이용하여 제주도 한천유역에 적용하여 전자파표면유속계의 관측 값과 비교한 결과 2~3m/s의 유속 분포를 보이고 있으며 통상적으로 관측된 홍수 유출시의 유속과 근사한 값을 보이고 있다. 향후 다양한 유출 사상에 대하여 SIV 기법을 적용하여 검증하고 동시에 다양한 유량 관측 기법과 비교 검토한다면 제주도의 체계적인 유량 관측 기술을 확립할 수 있을 것으로 판단된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.492-496
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• 2016

최근 4대강사업과 수질오염총량제 시행으로 하천의 구조적 및 비구조적 수질관리 환경의 커다란 변화에 따라 기존 모니터링지점에 대한 전면적인 재검토가 필요하다. 선정기준을 기반으로 평가기법은 공간적 대표성, 수리학적 안정성, 생태적 대표성, 시간적 대표성, 정보취득 안정성으로 5개의 특성과 14개의 평가부문 그리고, 평가항목으로 3단계 평가기법을 구성하여 개발하였다. 영산강 섬진강수계의 제주도수계 4개 중권역을 제외한 28개의 중권역을 대상으로 기존의 중권역 대표지점에 대하여 평가기법을 적용하여 그 적합성 평가를 실시하였다. 그 결과, 1등급이 8개 지점으로 29%, 2등급이 9개 지점으로 32%, 3등급이 6개 지점으로 21%, 4등급이 4개 지점으로 14%, 5등급은 1개 지점으로 4%를 차지하는 것으로 평가되었다.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.385-385
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• 2020

본 연구에서는 가뭄과 연관되는 다양한 관련 요인을 포함한 가뭄취약성 평가방안을 수립하고 이를 적용하는 것을 목표로 하였다. 평가기법은 평가인자와 가중치 선정, 평가자료 데이터베이스 구축, 평가자료와 가중치를 조합한 평가의 세 단계로 구성되었으며 평가인자 및 가중치 선정에는 Delphi 조사기법을 적용하고 평가기법으로는 최근 널리 적용되고 있는 MCDM (Multi-Criteria Decision Making) 방법인 TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) 기법을 활용하였다. 평가인자는 기상분야(Meteorological factors), 농업분야(Agricultural factors), 사회경제분야(Socioeconomic factors), 환경분야(Natural System)로 구성하였으며 선정된 인자에 대한 데이터베이스를 구성하기 위하여 기상청, 농어촌공사, 수자원공사 등의 관계기관이 관리하는 자료를 수집하였다. 수립한 가뭄취약성 평가방안을 2016년 3월부터 2019년 9월까지 우리나라 시군구 행정구역 단위, 총 167개 지역이며 순위법, 비율법, fuzzy 등 가중치 선정방법에 따라 결과에 약간의 차이가 나타난다. 가뭄예보결과와 취약성 평가결과를 비교해 보면 충청남도 홍성군이 동기간 동안 가뭄예경보 발령 횟수가 가장 많았으며, 충청남도 보령시와 서산시도 매우 높은 빈도로 확인되었다. 평가 결과, 충청북도, 경상남도, 전라남도에 가뭄 취약지역이 다수 도출 되어 이들 지역에 대한 가뭄 대응 방안 수립이 필요한 것으로 분석되었다.

• Journal of Advanced Technology Convergence
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• v.2 no.4
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• pp.7-11
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• 2023

In this study, we presented a method to recognize vehicle license plates using CNN techniques. A vehicle plate is normally used for the official identification purposes by the authorities. Most regular Optical Character Recognition (OCR) techniques perform well in recognizing printed characters on documents but cannot make out the registration number on the number plates. Besides, the existing approaches to plate number detection require that the vehicle is stationary and not in motion. To address these challenges to number plate detection we make the following contributions. We create a database of captured vehicle number plate's images and recognize the number plate character using Convolutional Neural Networks. The results of this study can be usefully used in parking management systems and enforcement cameras.

• Journal of KIISE
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• v.43 no.11
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• pp.1216-1222
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• 2016

The advent of large-scale web services has resulted in gradual increase in the amount of data used in those services. These big data are managed efficiently by DBMS such as MySQL and MariaDB, which use InnoDB engine as their storage engine, since InnoDB guarantees ACID and is suitable for handling large-scale data. To improve I/O performance, InnoDB caches data and index of its database through a buffer pool. It also supports multiple buffer pools to mitigate lock contentions. However, the multiple buffer pool scheme leads to the additional data consistency overhead. In this paper, we analyze the overhead of the multiple buffer pool scheme. In our experimental results, although multiple buffer pool scheme mitigates the lock contention by up to 46.3%, throughput of DMBS is significantly degraded by up to 50.6% due to increased disk I/O and fsync calls.

• KIISE Transactions on Computing Practices
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• v.23 no.5
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• pp.328-333
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• 2017

Mobile game apps, which are popular in various mobile devices, tend to be power-hungry and rapidly drain the device's battery. Since a long battery lifetime is a key design requirement of mobile devices, reducing the power consumption of mobile game apps has become an important research topic. In this paper, we investigate the power consumption characteristics of popular mobile games with multiple threads, focusing on the inter-thread. From our power measurement study of popular mobile game apps, we observed that some of these apps have abnormally high-load threads that barely affect the user's gaming experience, despite the high energy consumption. In order to reduce the wasted power from these abnormal threads, we propose a novel technique that detects such abnormal threads during run time and reduces their power consumption without degrading user experience. Our experimental results on an Android smartphone show that the proposed technique can reduce the energy consumption of mobile game apps by up to 58% without any negative impact on the user's gaming experience.

• Journal of Digital Contents Society
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• v.15 no.4
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• pp.457-464
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• 2014

Recently, interests in space information data are increasing due to the initiation of spatial information open platform service by the Ministry of Land, Infrastructure and Transport. The purpose of this study is optimizing management and storing of the texture data, one kinds of 3D-spatial data. First, extract 3D-spatial data through the aerial triangulation and 3D-writing using raw image taken with the Multi-directional aerial camera and the vertical aerial camera. And develop the method to create single texture data and related technique by align and place corresponding 3D-spatial data to optimal storage space. Through experiment, the results show effect of 8 times of storage capacity reduction compared to existing single-file storage method, additionally, new method can improve file management efficiency in comparison with multiple file storage method. The results of this study can be cornerstone of three-dimensional space information management when dealing with bulk data, and utilizations will be enhanced through the further studies and algorithm improvement.

• Korean Journal of Construction Engineering and Management
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• v.6 no.4 s.26
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• pp.133-141
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• 2005

The object of this study is to present performance by applying six sigma quality management to a construction company. The research method involves to investigate and analyze data regarding six sigma projects in S construction company and a questionnaire survey from the personnel of the S construction company. The results of this study are as follows 1) S construction company utilized the six sigma quality management for 258 projects during the years of 2003 and 2004 and this bring the effect of cost reduction for quality. Moreover, before using the six sigma quality management, the average level of sigma in this company was around 2.8, after using this, the level increased to 3.6. Particularly, the construction management part, the level increased from 1.3 to 2.6.2) respondents recognize that quality management costs by applying six sigma is reduced. but there is only a little operational efficiency because it is In the early stage of applying six sigma quality management.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.2
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• pp.1-7
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• 2013

Big data management is becoming increasingly important in both industry and academia of information science community. One of the important categories of big data generated from software systems is log data. Log data is generally used for better services in various service providers and can also be used as information for qualification. This paper presents a big data management architecture specialized for log data. Specifically, it provides the aggregation of log messages sent from multiple clients and provides intelligent functionalities such as analyzing log data. The proposed architecture supports an asynchronous process in client-server architectures to prevent the potential bottleneck of accessing data. Accordingly, it does not affect the client performance although using remote data store. We implement the proposed architecture and show that it works well for processing big log data. All components are implemented based on open source software and the developed prototypes are now publicly available.