• 품질경영학회지
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• 제49권1호
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• pp.1-15
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• 2021

Purpose: The purpose of this study was to propose a sensor fusion algorithm that integrates vehicle motion sensor(VMS) into the hybrid navigation system. Methods: How to evaluate the navigation performance was comparison test with the hybrid navigation system and the sensor fusion method. Results: The results of this study are as follows. It was found that the effects of the sensor fusion method and α value estimation were significant. Applying these greatly improves the navigation performance. Conclusion: For improving the reliability of navigation system, the sensor fusion method shows that the proposed method improves the navigation performance in a combat vehicle.

• 한국콘텐츠학회논문지
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• 제9권3호
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• pp.81-90
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• 2009

서비스지향구조 소프트웨어 품질평가는 품질 향상을 유도할 수 있는 기술로서 국제 표준을 수용하는 전략기술 개발을 통해 객관성과 활용도를 높일 수 있고 많은 소프트웨어 기업들이 비즈니스 요구사항과 연계된 솔루션을 구현하기 위한 방법으로 서비스지향구조 기법을 사용하고 있다. 또한, 정부차원의 시범사업이 추진되고 있으며 관련 업계의 기술 개발에 따라 서비스지향구조 기반 소프트웨어의 상용화가 확산되고 있다. 따라서, 본 연구에서는 서비스지향구조 기반 소프트웨어의 유지보수성 품질을 평가하기 위해 시험 메트릭을 제안하였고 품질을 측정하고 그 결과를 적절한 기준에 따라 판정하는 방법에 대해 연구를 수행하고 평가 사례를 제시하여 평가 방법을 명확히 제안하였다. 본 연구를 통해 서비스지향구조 기반 소프트웨어의 유지보수성 품질향상을 유도하고 서비스지향구조 기반 소프트웨어에 대한 양적/질적인 수요를 충족할 수 있다고 본다.

• 한국물환경학회지
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• 제31권3호
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• pp.272-285
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• 2015

Accurate assessment of chlorophyll-a (Chl-a) concentrations in inland waters using remote sensing is challenging due to the optical complexity of case 2 waters. and the inherent optical properties (IOPs) of natural waters are the most significant factors affecting light propagation within water columns, and thus play indispensable roles on estimation of Chl-a concentrations. Despite its importance, no IOPs retrieval model was specifically developed for inland water bodies, although significant efforts were made on oceanic inversion models. So we have applied and validated a recently developed Red-NIR three-band model and an IOPs Inversion Model for estimating Chl-a concentration and deriving inland water IOPs in Lake Uiam. Three band and IOPs based Chl-a estimation model accuracy was assessed with samples collected in different seasons. The results indicate that this models can be used to accurately retrieve Chl-a concentration and absorption coefficients. For all datasets the determination coefficients of the 3-band models versus Chl-a concentration ranged 0.65 and 0.88 and IOPs based model versus Chl-a concentration varied from 0.73 to 0.83 respectively. and Comparison between 3-band and IOPs based models showed significant performance with decrease of root mean square error from 18% to 33.6%. The results of this study provides the potential of effective methods for remote monitoring and water quality management in turbid inland water bodies using hyper-spectral remote sensing.

• 문화기술의 융합
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• 제5권3호
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• pp.333-338
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• 2019

문화콘텐츠는 고속, 고품질의 데이터 통신이 가장 핵심적인 요소이다. 고품질 콘텐츠로 VR AR 기술이 포함되고 다양한 고품질 콘텐츠는 스마트 폰을 통해 무선이동 중 스트리밍 서비스를 받을 수 있다. 또한, 사물이 무선인터넷에 연결을 하기위한 IoT(Internet of Things) 환경에서 네트워크 및 유무선 통신이 필연적으로 필요하다. IoT는 다양한 네트워크 기술로 4G, 5G 이동통신, WIFI 무선랜, 블루투스 등의 방식에 연결하여 사용되어 진다. 사물간의 연결을 언제 어디서나 이용할 수 있는 기술로 무선 이동통신 환경에서 이루어 질 수 있다. 따라서 본 논문에서는 고속 이동 환경에서도 고품질의 콘텐츠를 서비스 받을 수 있도록 이동통신 채널 환경 분석을 토대로 데이터 오류를 줄일 수 있는 데이터 오류 보상 추정 방식에 대해 연구한다.

• 비파괴검사학회지
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• 제21권6호
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• pp.618-629
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• 2001

본 논문은 고압 커패시터의 고장분석과 신뢰성 예측 결과를 다루고 있다. 부품의 수명과 고장률을 예측하기 위해서 두 가지 방법으로 고장 모드와 고장 메커니즘을 연구하였다 에폭시 수지로 성형된 고압 커패시터가 절연내압 시험 하에서 저항이 제로로 되는 고장에 대하여, 근본원인 고장분석 체계를 효과적으로 수립함으로써 고장 메커니즘의 원인을 분석하였다. 특히 세라믹-에폭시 계면에서의 절연파괴 고장 현상이 강조되었으며, 본 연구에서 얻어진 결과의 타당성은 마그네트론에 장착된 고압 커패시터의 열사이클 시험 수행에 의한 가속시험 결과로부터 입증되었다. 시험 결과들은 결함이 있는 로트를 신속히 규명하고 $B_{10}$ 수명을 결정하는데 유용하게 사용할 수 있다. 또한, 유전체의 절연파괴에 대해서 부하-강도 간섭모델을 이용하여 고장률을 예측하였다.

• 한국수산과학회지
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• 제34권4호
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• pp.348-354
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• 2001

This study was conducted to estimation of change characteristics for water quality by the dyke gate operation in the Keum River estuary. The estimation data made use of surveyed data in Keum River estuary by NERDI (National Fisheries Research and Development Institute) during $1990\~1999$. Shown to compare water quality changes at st. A and st. D in Figure 1, the concentrations of TSS, COD and nutrients at st. A were as high as about $2\~4$ times than those at st. D due to affection of fresh water discharge in the Keum River. The percentages of water quality change at surface water by dyke gate operation in the Keum River estuary were shown that TSS (Total Suspended Solid) was decrease to $56\%,\;47\%$ at st. A and D, and COD (Chemical Oxygen Demand) was increase to $68\%,\;71\%$ at st. A and D, respectively. The changes percentage of DIN (Dissolved Inorganic Nitrogen) by dyke gate operation in the Keum River estuary were increase high to $95\%$ at surface water and $7\sim30\%$ at bottom water, but those of DIP (Dissolved Inorganic Phosphorus) were increase to $2.8\sim8.6\%$ at surface water and $28\%$ at bottom water. The range of fluctuation for water quality at each station by dyke gate operation has shown that salinity and TSS are little better than before dyke gate operation, but COD show highly fluctuation. Also we studied estimation of characteristics of water quality change by the season, COD was increased except the summer, TSS was decreased to all season. DIN was increased to about $61\sim172.1\%$ for all season, but DIP was increased to the spring and decreased to the autumn, DIN enrichment in the estuary by dyke gate operation are interpreted to improvement of organic matter decomposition and nitrification by increasing the residence time and to increase nutrient flux in sediments due to decreasing dissolved oxygen and increasing a deposit matter.

• 한국IT서비스학회지
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• 제14권2호
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• pp.51-68
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• 2015

As interests in the quality of data in database systems are growing recently, analysis and improvement of data quality in databases have been an important issue. However, there has yet to be a clear agreement on how to reasonably calculate the total cost of such project. In this paper, based on real project data and budget statistics, we develop a model to estimate the cost for quality analysis and improvement project of a database. We first conduct statistical analysis to build our basic model. Throughout this analysis, we have identified factors that determine the scale of works required to conduct the project and eventually determine the cost. In addition, we have identified factors that determine the complexity of the project. These factors can adjusts the cost determined by the scale of works. Our model is verified and improved by surveys on experts. We apply our model to newly conducted projects and observe that our model estimates the cost of each project reasonably well.

• Journal of Communications and Networks
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• 제17권4호
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• pp.370-383
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• 2015

Effective link quality estimation is a vital issue for reliable routing in wireless networks. This paper studies the performance of expected transmission count (ETX) under different traffic loads. Although ETX shows good performance under light load, its performance gets significantly worse when the traffic load is high. A broadcast packet storm due to new route discoveries severely affects the link ETX values under high traffic load, which makes it difficult to find a good path. This paper presents the design and implementation of a variation of ETX called high load - ETX (HETX), which reduces the impact of route request broadcast packets to link metric values under high load. We also propose a reliable routing protocol using link quality metrics, which is called link quality distance vector (LQDV). We conducted the evaluation of the performance of three metrics - HETX, ETX and minimum hop-count. The simulation results show that HETX improves the average route throughput by up to 25% over ETX under high traffic load. Minimum hop-count has poor performance compared with both HETX and ETX at all of the different traffic loads. Under light load, HETX and ETX show the same performance.

• 상하수도학회지
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• 제25권4호
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• pp.547-554
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• 2011

In small-scale water systems, the measurement of quality of raw water in running water is generally implemented when the quality of water is stable and frequency of measurement is low. However, units such as water temperature and pH, which are easily monitored, are frequently measured. In establishing an improvement plan for a water treatment system, the range of concentration of the target material present in the raw water of the running water provides relevant information. If the concentration of target material can be specified by the quality of water of data items that are measured daily, inverse estimation of the range of concentration is possible as well. In this paper, we took note of manganese in the raw water from Ogasawara-mura, Tokyo, and estimated the manganese concentration in the raw water of the running water for the past five years. Based on the results obtained, we have proposed a manganese removal system, considering the current situation and geographical conditions of Ogasawara-mura.

• 한국음향학회지
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• 제37권6호
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• pp.512-517
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• 2018

음성 품질의 향상은 통신 분야의 주요 관심사이다. 본 논문에서는 VoIP(Voice-over-IP) 수신부에서의 배경잡음 및 패킷손실에 강인한 음질향상 방식을 제안한다. 제안된 방식에서는 하이브리드 마르코프 체인 기반 네트워크 지터추정, 추정된 지터를 이용한 적응적 플레이아웃 스케줄링, 그리고 진폭 및 위상 복원 기반의 음성 향상 방식 등을 결합하여 IP 네트워크를 통해 VoIP 수신부에 도착하는 음성신호의 품질을 향상시킨다. 실험결과는 제안된 방식이 송신부의 인코딩 전에 음성신호에 추가된 잡음을 제거하고 불안정한 네트워크 환경에서 양질의 음성을 제공하는 것을 확인할 수 있다.