• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.609-614
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• 1999

Our present ability to work with video has not been confined to wired communication environment. This paper describes the new technological trend of wireless video communication. In wireless video communication, unlike wired network, several techniques are needed. At first, error robust video coding is essential. Due to characteristics of wireless channel, the system is exposed to more error prone environment. In addition, encoded video bit streams are vulnerable to the error because of the entropy coding. Recently many frameworks are developed to cope with this problem. We just explore the numerous robust video coding approaches with the viewing of error control. And more we discuss other on going research topics in this wireless video communication fields like low-power assumption design, trans-codec technique, and rate control schemes in brief.

• International Journal of Aeronautical and Space Sciences
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• 제17권1호
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• pp.64-72
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• 2016

The coverage area of a GNSS regional ionospheric delay model is mainly determined by the distribution of GNSS ground monitoring stations. Extrapolation of the ionospheric model data can extend the coverage area. An extrapolation algorithm, which combines observed ionospheric delay with the environmental parameters, is proposed. Neural network and least square regression algorithms are developed to utilize the combined input data. The bi-harmonic spline method is also tested for comparison. The IGS ionosphere map data is used to simulate the delays and to compute the extrapolation error statistics. The neural network method outperforms the other methods and demonstrates a high extrapolation accuracy. In order to determine the directional characteristics, the estimation error is classified into four direction components. The South extrapolation area yields the largest estimation error followed by North area, which yields the second-largest error.

• 물과 미래
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• 제23권1호
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• pp.79-87
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• 1990

본 연구에서는 회귀모형의 오차분석을 모형오차분석과 표본오차분산으로 분리하므로써 오차분산에 대한 합리적이고도 편의되지 않은 추정량을 제공해 줄 수 있는 일반화 최소자승법을 이용하여 한강 및 낙동강유역의 유량관측점에서 수집된 연최대홍수량 자료를 유역특성 및 강우량 자료와 연관시키는 지역화회귀모형을 개발하였다. 본 모형은 계측지점으로부터 미계측지점으로 수문정보를 전달해주기 위한 수단으로 사용될 수 있다.

• Steel and Composite Structures
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• 제46권2호
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• pp.221-236
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• 2023

In order to study the seismic response of the main plant of steel reinforced concrete (SRC) structure of the CAP1400 nuclear power plant under the influence of different high-mode vibration, the 1/7 model structure was manufactured and its dynamic characteristics was tested. Secondly, the finite element model of SRC frame-bent structure was established, the seismic response was analyzed by mode-superposition response spectrum method. Taking the combination result of the 500 vibration modes as the standard, the error of the base reactions, inter-story drift, bending moment and shear of different modes were calculated. Then, based on the results, the influence of high-mode vibration on the seismic response of the SRC frame-bent structure of the main plant was analyzed. The results show that when the 34 vibration modes were intercepted, the mass participation coefficient of the vertical and horizontal vibration mode was above 90%, which can meet the requirements of design code. There is a large error between the seismic response calculated by the 34 and 500 vibration modes, and the error decreases as the number of modes increases. When 60 modes were selected, the error can be reduced to about 1%. The error of the maximum bottom moment of the bottom column appeared in the position of the bent column. Finally, according to the characteristics of the seismic influence coefficient αj of each mode, the mode contribution coefficient γj•Xji was defined to reflect the contribution of each mode to the seismic action.

• 한국전기전자재료학회논문지
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• 제24권12호
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• pp.949-954
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• 2011

In this study, the characteristics and error ranges of the mechanical bonding strength were analyzed according to before and after thermal shock test for various chips of automotive application component using Sn-3.0Ag-0.5Cu solder. In the after thermal shock test, the mechanical bonding strengths tend to decrease, meanwhile decreasing rates of mechanical strengths were less then 12% at specimen's bonding area below 3.5$mm^2$, and were from 17 to 21% at specimen's bonding area above 12 $mm^2$. On the other hand, Specimen's mean deviation rates were about 5% at specimen's bonding area more than 12 $mm^2$. Inversely, at specimen's bonding area is less then 3.5 $mm^2$, mean deviation rates were increased to about 8%. It means that the smaller device size is, the larger mean deviation rate. In addition, error ranges and deviation rates of the mechanical bonding strengths may differ slightly depending on their bonding area. Furthermore, process conditions as well as method of mechanical reliability evaluation should be established to reduce the error ranges of bonding strength.

• 대한전자공학회논문지TC
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• 제48권10호
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• pp.13-19
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• 2011

이 논문은 위성항법시스템을 이용한 위치측위에서 지역별 특성에 따른 위치오차실험을 통하여, 음영지역 발생 원인과 해결 방법을 제안하기 위한 연구이다. 동적측위에서 이동체는 이동 위치에 따라 사용할 수 있는 위성항법시스템의 수가 변화한다. 정확한 위치측위를 위해서는 4개 이상의 위성항법시스템으로부터 위치정보데이터를 수신 받아야 한다. 하지만 급격한 산업화와 열악한 지역 환경으로 위치오차가 커지고 음영지역이 발생한다. 이러한 위치오차를 줄이고 음영지역 발생을 해소하기 위해서는 대도시의 환경과 지역 환경 특성에 따른 원인을 파악하는 것이 중요하다. 따라서 본 논문에서는 대도시, 주택 지역, 숲 지역, 바다 지역, 대지 등을 선정하여 위치오차와 음영지역 발생 원인을 실험하였다. 그리고 이 논문을 기반으로 지역 환경에 따른 적합한 고정밀 측위 알고리즘을 제안하고, 음영지역해소 알고리즘을 제안하려고 한다.

• 한국가스학회지
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• 제18권4호
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• pp.68-75
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• 2014

독성가스시설에서 대형사고로 인한 손실을 감소시키기 위해서는 인적요소를 제어하고, 평가하는 것이 필요하다. 기존의 안전성 평가는 기계적 결함이나 시스템의 위험이 주로 강조되어 왔으며, 인적오류를 관리하는 평가방법이 부족하여 본 연구에서는 독성가스시설의 사고관리 상황에서 인적오류를 구성하는 수행영향인자 분류체계를 제안하고자 하였다. 이를 위해 주요 수행영향인자 분류체계의 유형을 수집하여 검토와 분석을 한 후 4가지(작업자 특성, 시스템, 직무특성 및 직무환경)로 나누고, 독성가스시설의 상황적 특성과 직무특성 및 작업환경을 고려하여 수행영향인자를 선택하였다. 이로 부터 인적오류의 평가에 사용하기 적절한 수행영향인자 체계를 구축하고, 구축한 수행영향인자 분류체계를 독성가스시설에서 발생하였던 사고 사례분석을 통해 적용성을 검토하였다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2019년도 추계학술대회
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• pp.265-265
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• 2019

선박을 조종할 때 발생하는 항해사의 인적오류로 인해 해양사고는 매년 꾸준히 발생하고 있다. 이 연구의 목적은 해기사가 선박조종에 나타난 행동으로 인해 발생하는 인적오류에 의해서 야기 될 수 있는 선박충돌사고를 예방하여 항행안전을 도모하는 것이다. 해기사의 행동으로 발생하는 인적오류를 관리 할 수 있는 방법은 두 가지이다. 개인 접근법과 시스템 접근법으로 구분되며, 이는 상황인식이론과 라스무센의 행동이론으로 적용되었다. 이를 과거 해양사고에서 발생한 인적오류를 조사하고, 선박조종시뮬레이터를 이용하여 실험을 진행해 이 두 가지 행동 특성을 식별하였다. 두 가지 해기사 인적오류 특성을 분석하였으며, 이를 기반으로 추후에는 대응 방법을 제안하고자 한다.

• 음성과학
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• 제8권1호
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• pp.123-133
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• 2001

This case study investigated the assessment and treatment of bilingual children using a 4.5 year old bilingual child. We also compared treatment methods for bilingual children in the U.S. and in Korea, respectively. Given the lack of unbiased assessment tools, it was difficult to evaluate the child properly. In addition, the study of the linguistic characteristics of bilingual children have not been researched extensively in Korea. As a result, there were limitations in assessing the child. However, once all requisite information had been gathered, he was assessed as a bilingual child with specific language impairment (SLI) and his skill in both languages was considered equivalent. During treatment sessions, the child exhibited diverse linguistic characteristics and interesting error patterns which were not evident in monolingual SLI. However, it was difficult to assess whether the error patterns exhibited by the subject were attributable to his own bilingual characteristics or not. This was further complicated by the lack of previous research on the bilingual child's linguistic characteristics. His progress differed from one area to another. Furthermore, we illustrated some of the limitations in assessing bilingual children and proposed several considerations that should be met before treatment is initiated.

• 사상체질의학회지
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• 제18권2호
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• pp.34-40
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• 2006

1. Objectives We are going to develope 3D Face Recognition Apparatus to analyse the facial characteristics of the Sasangin. In the process, we should identify the recognition rate of the three dimensional position using this Apparatus. 2. Methods We took a photograph of calibrator($280{\times}400mm$) with interval of 20mm longitudinal direction of 10 times using 3D Face Recognition Apparatus. In the practice, we obtained 967 point to the exclusion of points deviating from the visual field of dual camera. And we made a comparison between measurement values and three dimensional standard values to calculate the errors. 3. Results and Conclusions In this test, the average error rate of X axis values was 0.019% and the maximum error rate of X axis values was 0.033%, the average error rate of Y axis values was 0.025% and the maximum error rate of Y axis values was 0.044%, the average error rate of Z axis values was 0.158% and the maximum error rate of Z axis values was 0.269%. This results exhibit much improvement upon the average error rate 1% and the maximum error rate 2.242% of the existing 3D Recognition Apparatus. In conclusion, we assessed that this apparatus was adaptable to abstract the facial characteristic point from three dimensional face shape in the mechanical aspects.