• The Science & Technology
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• v.33 no.12 s.379
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• pp.50-52
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• 2000

수급악화로 고유가 시대 장기지속 전망, 경제구조 에너지 저소비형으로 바꿔야

• 산림경영
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• s.150
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• pp.34-34
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• 2001

산림청 남부지방산림관리청 울진국유림관리소에서 가시가 전혀 없는 음나무(일명 개두릅)를 생산하는데 성공했다. 대량증식을 통하여 2002년 재배농가에 보급하여 농가소득원으로 활용할 계획이다.

• Journal of the Korean Association of Geographic Information Studies
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• v.14 no.1
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• pp.40-48
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• 2011

The purpose of this study is to contribute enhancing the accuracy of viewshed analysis through the explanation for an analysis method of viewshed analysis using GIS. According to previous studies, the visible area using digital terrain in viewshed analysis depends on a visible interest area, scale of terrain, spatial resolution and surface data. In this study, we used trend analysis and RMSE analysis in order to find the effect of a visible interest area, scale of terrain, etc in viewshed analysis. Results of this study are as follows. First, the result of viewshed analysis depends on a visible interest area, scale of terrain, spatial resolution, surface data such as previous studies. Second, the results in forest area are reliable than those of flat area in terms of a visible interest area. Third, the results based on raster grid data are stable than those of TIN(triangulated irregular network) in terms of input surface data. Fourth, according to the result of trend and RMSE analysis, the spatial resolution for analysis is differently applied to different scales digital terrain map in viewshed analysis. In detail, it is desirable that the spatial resolution is set less than 10m(in the case of 1/1,000 digital terrain map), 20m(in the case of 1/5,000 map), 30m(1/25,000 map).

• Korean Journal of Cognitive Science
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• v.27 no.2
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• pp.275-301
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• 2016

Attentional blink (AB) refers to the phenomena where conscious report for a target (T2) subsequent to the first target (T1) in a stream of items under rapid serial visual presentation (RSVP) becomes difficult if the T2 follows no later than 500ms after the T1. The present study examined the effect of T1 visibility on T2 AB strength according to the bottleneck account proposing that the amount of allocated resources for T1 memory consolidation determines the strength of AB against T2. In the low-visibility condition, the T1 had a gray color for a low stimulus contrast against the black background whereas had a bright and saturated color in the high-visibility condition. In both visibility conditions, the T1 was also highly distinct from the remaining distractors. A multi-RSVP method was also used for increasing location uncertainty of the targets supposedly consuming on average attentional resources for the targets. Two experiments revealed that AB strength was more intense in the low-visibility than high-visibility condition, and the pattern of difference went more pronounced if T2 visibility was improved. The results indicate that T1 visibility can affect more strongly when attentional resources are relatively lacking for resolving the T1 bottleneck, and support for the bottleneck account proposing that the level of T1's visibility can determine the intensity of the T1 bottleneck.

• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.103-108
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• 2007

최근 프로젝터의 보편화로 인해 프로젝터를 증강현실의 디스플레이 장치로 활용하는 연구가 활발히 진행되고 있다. 관련 연구들을 흔히 프로젝션 기반 증강현실이라고 부른다. 프로젝션 기반 증강현실을 구현하기 위해서는 스크린의 기하(geometry) 및 컬러(photometry) 정보를 획득하는 과정이 선행되어야 하는데, 이는 프로젝터를 이용하여 정해진 패턴 영상을 투사하고 이를 카메라로 캡쳐한 후, 카메라 영상에 다양한 컴퓨터비전 기술들을 적용함으로써 행해진다. 이러한 스크린 기하 및 컬러 정보 획득 기술은 가시적인(visible) 패턴 영상이 사용자의 몰입감을 저해한다는 단점을 가진다. 특히, 스크린의 기하 및 컬러 정보가 수시로 변하는 환경에서는 가시적인 패턴 영상을 사용하는 기존의 스크린 기하 및 컬러 정보 획득 기술은 유용하지 못하다. 이러한 문제점을 해결하기 위해 일부 패턴 영상을 비가시적(invisible)으로 만드는 기술들이 제안되었다. 본 논문에서는 관련 기술들을 비간섭 프로젝션 기반 증강현실이라고 한다. 특히, 보색 패턴(complementary patterns)을 증강현실 영상에 삽입하는 방법은 부가적인 장비없이 간단한 영상처리만으로 효과적으로 패턴 영상을 비가시적으로 만들어 줄 수 있으며, 최근 가상 스튜디오에 활용하는 방안이 모색되고 있다. 그러나, 삽입된 보색 패턴의 세기와 비가시성 사이는 상반관계(trade-off)를 가지므로, 일반적인 환경에서는 보색 패턴의 비가시성을 보장할 수 없다. 본 논문에서는 이러한 보색 패턴의 비가시성을 극대화하기 위해 컨텐츠 적응형 패턴 삽입 기술을 제안한다. 증강현실 영상의 색감 및 텍스처의 복잡도에 따라 크게 4 가지 경우로 분류하여 부분적으로 다른 채널 및 세기로 보색 패턴을 삽입한다. YIQ 컬러 공간에서 표현된 증강현실 영상을 균일한 크기의 영역으로 나눈 다음, 각 영역에 대해 I 성분이 지배적이면 Q 채널에 패턴을 삽입하고 Q 성분이 지배적이면 I 채널에 패턴을 삽입한다. 한편, 각 영역에 대해 텍스처의 복잡도가 크다면 강한 패턴을, 복잡도가 작으면 약한 패턴을 삽입한다. 여기서, 텍스처의 복잡도는 간단한 미분 필터(derivative filter)를 이용하여 계산된다. 다양한 실험 및 사용자 평가를 통해, 제안된 방법은 기존 방법에 비해 크게 두 가지 상반관계를 가지는 장점을 가짐을 확인하였다. 스크린의 기하 및 컬러 정보를 획득하는 성능 면에서 제안된 방법이 기존의 방법과 유사하도록 채널 및 패턴의 세기를 결정한다면, 기존의 방법에 비해 패턴의 비가시성이 크게 개선된다. 반대로, 제안된 방법의 패턴의 비가시성이 기존의 방법과 유사하도록 채널 및 패턴의 세기를 결정한다면, 기존의 방법에 비해 스크린의 기하 및 컬러 정보를 획득하는 성능이 크게 개선된다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.4
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• pp.444-450
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• 1995

It was very hard to gather the seeds of Eleutherococcus senticosus Max. known as a medicinal plant for they tend to drop under the high temperature condition during the summer period in Korea. Therefore, this study was conducted to select seed production site for Eleutherococcus senticosus in Korea, comparing the climate of Hokkaido of Japan, in which the seeds have been produced, with that of various place in this country. It was low that the average maximum temperature during the hottest summer two months (July and August) as a 24.4$^{\circ}C$ in Hokkaido and 21.2$^{\circ}C$ in Daegwanryeong compared with 27.4$^{\circ}C$ in Changsu. Especially in Daegwanryeong, average maximum temperature from June to September remained as low as 21$^{\circ}C$. Effective accumulated temperature(>5$^{\circ}C$) was 807$^{\circ}C$ in Hokkaido and 964$^{\circ}C$ in Daegwanryeong during the ripening period. Monthly sunshined hours from July to August were 121.7~128 hours in Daegwanryeong and 83.5~85.4 hours in Hokkaido. The Eleutherococcus senticosus sprouts at 8.5$^{\circ}C$, comes to flowering season in mid-August, and ripens during late-August and October in Hokkaido, the climate of which is similar to that of Daegwanryeong.

• The KIPS Transactions:PartA
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• v.15A no.1
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• pp.1-8
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• 2008

An occlusion culling method, one of visibility culling methods, excludes invisible objects or triangles which are covered by other objects. As it reduces computation quantity, occlusion culling is an effective method to handle complex scenes in real-time. But an existing common occlusion culling method, such as hardware occlusion query method, sends objects' data twice to GPU and this causes processing overheads once for occlusion culling test and the other is for rendering. And another existing hardware occlusion culling method, VCBP, can test objects' visibility quickly, but it neither test bounding volume nor return test result to application stage. In this paper, we propose a single pass occlusion culling method which uses temporal and spatial coherency, with effective occlusion culling hardware architecture. In our approach, the hardware performs occlusion culling test rapidly with cache on the rasterization stage where triangles are transformed into fragments. At the same time, hardware sends each primitive's visibility information to application stage. As a result, the application stage reduces data transmission quantity by excluding covered objects using the visibility information on previous frame and hierarchical spatial tree. Our proposed method improved maximum 44%, minimum 14% compared with S&W method based on hardware occlusion query. And the performance is increased 25% and 17% respectively, compared to maximum and minimum performance of CHC method which is based on occlusion culling method.

• Journal of Wetlands Research
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• v.12 no.3
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• pp.49-56
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• 2010

Euryale ferox is only annual hydrophyte among endangered plants in Korea and its seed is high valuable medicinal material. This studies were carried to find out key factors that made E. ferox endanger in Korea and to apply the results for effective management of the natural wetlands inhabited by E. ferox. We investigated the distributed sites reported by previous studies and classified the distribution-affected factors into three categories, eutrophication(hypothesis 1), soil accumulation(hypothesis 2) and increasing of water level(hypothesis 3) in the habitat. These three hypotheses were tested in the field and explained the results with the morphological characteristics of seed germination stages of E. ferox. The geographical distribution ranges of E. ferox diminished at a rate of $1^{\circ}$ latitude with about 10 natural wetlands for last 30 years. Water eutrophication in the wetland had a positive effect on the establishment of E. ferox. But higher in soil accumulation and water depth, then lower in the establishment rate of E. ferox. These results indicate that water depth in the wetland must be below 50cm during the germination season, especially in May and emergent hydrophytes filter zone is need to protect soil accumulation from soil erosion within its watershed for the effective management of wetland with E. ferox.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.2
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• pp.401-407
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• 2016

We can consider the following problems for two given points p and q in a simple polygon P. (1) Compute the set of points of P which are visible from both p and q. (2) Compute the set of points of P which are visible from either p or q. They are corresponding to the problems which are to compute the intersection and the union of two visibility polygons. In this paper, we consider algorithms for solving these problems on a reconfigurable mesh(in short, RMESH). The algorithm in [1] can compute the intersection of two general polygons in constant time on an RMESH with size O($n^3$), where n is the total number of vertices of two polygons. In this paper, we construct the planar subdivision graph in constant time on an RMESH with size O($n^2$) using the properties of the visibility polygon for preprocessing. Then we present O($log^2n$) time algorithms for computing the union as well as the intersection of two visibility polygons, which improve the processor-time product from O($n^3$) to O($n^2log^2n$).

• Journal of the Korea Society for Simulation
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• v.15 no.2
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• pp.31-39
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• 2006

The visibility graph is a well-known method for efficient path-finding with the minimum search space modelling the game world. The generalized visibility graph is constructed on the expanded obstacle boundaries to eliminate the "wall-hugging" problem which is a major disadvantage of using the visibility graph. The paths generated by the generalized visibility graph are guaranteed to be near optimal and natural-looking. In this paper we propose the method to apply the generalized visibility graph efficiently for game characters who moves among static obstacles between varying start and goal points. Even though the space is minimal once the generalized visibility graph is constructed, the construction itself is time-consuming in checking the intersection between every two links connecting nodes. The idea is that we build the map for static obstacles first and then incorporate start and goal nodes quickly. The incorporation of start and goal nodes is the part that must be executed repeatedly. Therefore we propose to use the rotational plane-sweep algorithm in the computational geometry for incorporating start and goal nodes efficiently. The simulation result shows that the execution time has been improved by 39%-68% according to running times in the game environment with multiple static obstacles.