• Journal of Broadcast Engineering
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• v.24 no.4
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• pp.564-572
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• 2019

With the development of deep learning, the performance of facial landmark detection methods has been greatly improved. The heat map regression method, which is a representative facial landmark detection method, is widely used as an efficient and robust method. However, the landmark coordinates cannot be directly obtained through a single network, and the accuracy is reduced in determining the landmark coordinates from the heat map. To solve these problems, we propose to combine integral regression with the existing heat map regression method. Through experiments using various datasets, we show that the proposed integral regression network significantly improves the performance of facial landmark detection.

• Journal of Korea Game Society
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• v.20 no.3
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• pp.65-74
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• 2020

In the shadow map method, if the shadow map is magnified, the shadow has a jagged silhouette. Herein, we propose a soft shadow method that filters reshaped silhouettes analytically. First, the shadow silhouette is reshaped through sub-texel edge detection, which is based on linear or quadratic curve models. Second, an integral shadow filtering algorithm is used to accurately obtain the average shadow intensity from a definite integral estimation. The implementation demonstrates that our solution can effectively eliminate jagged aliasing and efficiently generate soft shadows.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.5
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• pp.1-8
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• 2002

For gasoline engines, a three-way catalytic converter that has the maximum efficiency at stoichiometric air/fuel ratio is used to clean up the exhaust gas. So a precise air/fuel ratio control is necessary to maximize the catalytic conversion efficiency, For a transient condition, a fred-forward air/fuel ratio control method that estimates the air mass inducted into a cylinder is being used. In this study, a fuel injection map that makes an accurate air/fuel ratio control possible was constructed for the very same transient condition. For the same condition above, intake air model and fuel model were refined so that fuel injection values based on air mass through a throttle valve and intake manifold pressure are equal to the map values.

• Journal of the Korea Computer Graphics Society
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• v.17 no.2
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• pp.11-16
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• 2011

In computer graphics, shadows play a very important role as a hint of inter-object distance as well as themselves in terms of realism. To represent shadows, some traditional methods such as shadow mapping and shadow volume have been frequently used for the purpose. However, the rendering results are not natural since they assume the point light. On the contrary, an area light can render soft-shadows, but its computation is too burdensome due to integral over the whole light source surface. Many alternatives have been introduced, back-projection of occluder onto the light source to get visibility of light or filtering of shadow boundary by calculating size of penumbra. But they also have problems of light bleeding or ringing effects because of low order approximation, or low performance. In this paper, we describe a method to improve those problems using shadow atlas.

• The Journal of the Korea Contents Association
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• v.5 no.5
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• pp.296-304
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• 2005

Quantitative analysis compare to dynamic characteristic change of the regional cerebral blood volume(rCBV) after development of cerebral fat embolism in cats using perfusion magnetic resonance(MR) Imaging. Twenty cats were used. Linoleic acid (n=11) were injected into the internal carotid artery using microcatheter through the transfemoral approach. Polyvinyl alcohol (Ivalon) (n=9) was injected as a control group. Perfusion MR images were obtained at 30 minutes and 2 hours after embolization, based on T2 and diffusion-weighted images. The data was time-to-signal intensity curve and ${\Delta}R_2^*$ curve were obtained continuously with the aid of home-maid image process algorithm and IDL(interactive data Banguage, USA) softwares. The ratios of rCBV increased significantly at 2 hours compared with those of 30 minutes (P<0.005). In conclusion, cerebral blood flow decreased in cerebral fat embolism immediately after embolization and recovered remarkably in time course. It is thought that clinically informations to dynamic characteristic change of the cerebral hemodynamics to the early finding in cerebral infarction by diffusion weighted imaging(DWI) and perfusion weighted imaging(PWI).

• Journal of Korea Game Society
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• v.12 no.5
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• pp.67-78
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• 2012

Summed area table allows filtering of arbitrary-width box regions for every pixel in constant time per pixel. This characteristic makes it beneficial in image processing applications where the sum or average of the surrounding pixel intensity is required. Although calculating the summed area table of an image data is primarily a memory bound job consisting of row or column-wise summation, previous works had to endure excessive access to the high latency global memory in order to exploit data parallelism. In this paper, we propose an efficient algorithm for generating the summed area table in the GPGPU environment where the input is decomposed into square sub-images with intermediate data that are propagated between them. By doing so, the global memory access is almost halved compared to the previous methods making an efficient use of the available memory bandwidth. The results show a substantial increase in performance.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.351-351
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• 2011

최근 지구온난화와 더불어 이상기후가 대두됨에 따라 기상 예측이 더욱더 중요시되고 있다. 또한 이전부터 가뭄 및 홍수와 같은 기상현상으로 인한 피해 사례가 빈번하였으며, 이로 인하여 물 관리의 어려움을 겪고 있다. 한 예로 이상기후가 유난히 잦았던 2010년 여름철 경우 평년보다 발달한 북태평양고기압의 영향으로 여름철 92일 가운데 81일의 전국 평균기온이 평년보다 높게 나타났다. 또한 강우 일수가 평년에 비해 7.4일 많은 44.2일을 기록하였으며, 국지성 집중호우 사례가 빈번하였다. 또한 8월 9일 발생한 태풍 `뎬무'를 포함해서 한 달 동안 3개의 태풍이 한반도에 영향을 끼치는 이례적인 사례가 발생하였다. 따라서 본 연구는 이러한 기상재해에 따른 물 관리를 장기적으로 대비하고자 고해상도 전지구 모델 GME를 이용하여 2010년 여름철 강수 예측을 실시하였다. 강수 예측에 사용된 전지구 모델 GME는 기존의 카테시안 격자체계를 가진 모델과 달리 전구를 삼각형으로 구성된 20면체로 격자화 한 Icosahedral-hexagonal grid 격자체계로 구성되어 있어, 해상도 증가에 용이할 뿐만 아니라, HPC(High Performance Computing)환경에서 효율성이 높은 장점을 가지고 있다. 본 계절 예측을 수행함에 있어 발생하는 잡음을 최소화하고자, Time-lag 기법을 이용하여 5개의 앙상블 멤버로 구성되어있으며, 이를 비교 분석하기위해 Climatology를 이용하여 총 10개의 앙상블 멤버로 규준실험을 수행하였다. 선행 연구에 따르면 1개월 이상의 장기 적분의 경우 초기조건보다 외부 강제력이 더 중요한 역할을 한다고 연구된 바 있다. (Yang et al., 1998) 특히 계절 변동성의 경우 대기-해양간의 상호작용에 의해 지배되며, 이를 고려하여 본 연구는 해수면 온도를 경계 자료로 사용하여 계절 예측을 수행하였다. 앞서 말한 실험 계획을 바탕으로 하여 나온 결과를 통해 동아시아지역 및 한반도 도별 강수 및 온도 변수에 대해 순별 및 월별 카테고리맵 분석을 실시하여 한눈에 보기 쉽게 나타냈다. 또한 주요 도시별 강수량 및 온도의 시계열 분석을 실시하여 시간이 지남에 따라 나타나는 변동성을 확인하였다. 계절 예측 결과에서 온도의 경우 평년보다 높게 나타났으며, 이는 실제 온도 예측과도 유사한 패턴을 가졌다, 강수의 경우 7월부터 8월 중순까지 평년보다 다소 적게 모의되었으며, 8월 하순경 회복하는 것으로 예측하였다. 따라서 본 계절 강수 예측은 다소 역학 모델이 가지는 한계를 가지고 있으나, 실제와 비교하여 어느 정도의 경향성이나 패턴에 있어 유사성을 보임을 확인하였으며, 이를 장기적 차원의 물관리를 함에 있어 참고 및 활용 가능할 것으로 예상한다.