• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2016.06a
• /
• pp.349-351
• /
• 2016

본 논문에서는 VR 영상의 스티칭을 위한 특징점 추출 방식의 하나인 SIFT 알고리즘의 고속화 방법을 제안한다. 이 방법은 SIFT 의 각 단계 모두에 최적화 방법을 적용하여 CPU 에 최적화된 알고리즘을 구축하였다. 그리고 비독립적인 과정들로 이루어진 SIFT 특징점 추출 연산을 병렬화하기 위한 방법으로, 영상 분할 방법을 제시하며 SIFT 의 새로운 병렬화 방법을 제안한다. 특히 최적화 과정을 통해 Scale-space Extrema Detection 과 Orientation Assignment 과정에서 큰 시간 단축 효과를 보여 총 75.5%의 시간을 단축하였다. 이를 OpenMP 와 영상 분할 방법을 활용한 CPU 병렬화로 FullHD($1920{\times}1080$)해상도 영상에서 약 4000 개의 특징점을 추출하는 데 평균 91ms 의 성능을 보이며 기존 GPU 고속화 논문 대비 약 30%의 성능 개선 효과를 보였다.

• Journal of Chest Surgery
• /
• v.12 no.1
• /
• pp.43-49
• /
• 1979

This is a case report of surgically treated rupture of Valsalva Sinus aneurysm combined with VSD. He has been relatively healthy until about one month before admission, when during bath, he felt abruptly palpitation, left chest pain and exertional dyspnea. These symptoms have progressed. On admission, thrill was palpable and continuous machinery murmur was audible on 2nd and 3rd intercostal space along the left sternal border. A rupture of Valsalva`s sinus aneurysm was confirmed by aortography and echocardiography but a small VSD was found by cardiotomy in open heart surgery. On 11th Sep. 1978, open heart surgery was performed. Valsalva`s sinus aneurysm came out from right coronary aortic sinus and ruptured into the right ventricle. It sized 1.2X1.5X1.5 cm. Ruptured opening was noted on apex of aneurysm [0.8X0.8cm], VSD [1. 0X0. 3cm in size] was just below the aortic annulus. The aneurysmal sac was removed on neck. After that, VSD and aneurysmal orifice were closed together with interrupted mattress sutures on same plane. The postoperative course was uneventful and discharged three weeks after open heart surgery.

• Journal of the Korean Institute of Educational Facilities
• /
• v.7 no.2
• /
• pp.15-21
• /
• 2000

Microclimate of open spaces on campus tends to be important because it is related with people's comfort and it can influences their behaviors in outdoor during summer. Climatic components for 4 points, concrete paving, lawn, landscaped pergola and nearby forest on university campus were measured and evaluated. The results show that the air temperatures on paving such as concrete and lawn under the direct solar radiation were higher than the temperatures of canopied spaces such as pergora and nearby forest by up to $7^{\circ}C$ during summer. Characteristics of temperatures on lawn were similar to those on concrete paving. After evaluation, concrete surface was worst among 4 points, while landscaped pergola was the most effective facility in terms of thermal comfort during summer.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.10 no.2
• /
• pp.147-154
• /
• 1998

This study was carried out for evaluating the interior thermal environment in KBS Open hall with large ceiling height and large space. Ventilation systems of KBS Open hall have combined mixing ventilation and downward displacement ventilation system. Temperature and velocity was measured 130 locations with low level(0.1m), mid level(0.6m) and high level(1.1m). But relative humidity was measured at 15 locations. The subjective thermal sensation was made an inquiry of occupancy at the location measured physical elements.

• The Bulletin of The Korean Astronomical Society
• /
• v.41 no.2
• /
• pp.53.2-53.2
• /
• 2016

We present our experiences with open-source spatio-temporal database systems for managing and analyzing big astronomical data acquired by wide-field time-domain sky surveys. Considering performance, cost, difficulty, and scalability of the database systems, we conduct comparison studies of open-source spatio-temporal databases such as GeoMesa and PostGIS that are already being used for handling big geographical data. Our experiments include ingesting, indexing, and querying millions or billions of astronomical spatio-temporal data. We choose the public VVV (VISTA Variables in the Via Lactea) catalogs of billions measurements for hundreds of millions objects as the test data. We discuss issues of how these spatio-temporal database systems can be adopted in the astronomy community.

• The Bulletin of The Korean Astronomical Society
• /
• v.42 no.2
• /
• pp.88.3-89
• /
• 2017

We present our experiences with open-source NoSQL database systems in analyzing spatial and temporal astronomical data. We conduct experiments of using Redis in-memory NoSQL database system by modifying and exploiting its support of geohash for astronmical spatial data. Our experiment focuses on performance, cost, difficulty, and scalability of the database system. We also test OpenTSDB as a possible NoSQL database system to process astronomical time-series data. Our experiments include ingesting, indexing, and querying millions or billions of astronomical time-series measurements. We choose our KMTNet data and the public VVV (VISTA Variables in the Via Lactea) catalogs as test data. We discuss issues in using these NoSQL database systems in astronomy.

• Journal of Navigation and Port Research
• /
• v.26 no.4
• /
• pp.449-453
• /
• 2002

Recently a ship manoeuvring simulator has been developed by Korea Maritime University. We are desiring to apply the movement of wave to the visual scene of sea state in the simulator. This paper discussed the calculation method and visualization simulation of three dimensional sea state using OpenGL API, and the possibility to apply calculation result to the simulator.

• Proceedings of the KSR Conference
• /
• 2009.05a
• /
• pp.688-694
• /
• 2009

As a drive system for next generation train, we have been making research and development of a direct drive traction motor system without the conventional reduction gear. This traction motor is expected to have many advantages such as low noise, reduced maintenance, and energy saving. Due to the demand for high-output motors in the limited space between the wheels, open-ventilating traction motors with gear box have been widely used for many years. However, a conventional open-ventilating traction motor is necessary periodical disassembly to remove the accumulated dust from open-air ventilation. Reducing this burden, as well as increasing energy efficiency and reducing noise, would benefit the next generation of traction motors. To address these needs, KRRI have been developing a fully enclosed type direct drive motor(DDM) with high-efficiency permanent magnet for the next generation train.

• Journal of the Korean Institute of Landscape Architecture International Edition
• /
• no.1
• /
• pp.53-58
• /
• 2001

The study made a comparison of the draft making process and implementation of open spaces in Japan and China, and pointed out the issues to be solved. In summary, we discovered that the Japanese plan emphasizes joint conduct and cooperation between residents and corporation/organization, while the Chinese plan is characterized by its active usage of administrative lines. Regarding the policies of their plans, there are many similarities in the basic issues for both countries. The study clarified the differences in measures responding to geographical and systematic features of each country.

• The Transactions of the Korea Information Processing Society
• /
• v.6 no.3
• /
• pp.821-831
• /
• 1999

Recognition of three-dimensional objects with convexities and concavities is a hard and challenging problem. This paper presents a feature extraction method out of three-dimensional objects for the purpose of classification. This new method not only provides invariance to scale, translation, and rotation $R^3$ but also distinguishes any three-dimensional model objects with concavities and convexities by measuring a relative similarity in the information space where a set of characteristics features of objects is mapped.