• Journal of KIISE:Software and Applications
• /
• v.30 no.5_6
• /
• pp.497-502
• /
• 2003

Content-based video copy detection is a complementary approach to watermarking. As opposed to watermarking, which relies on inserting a distinct pattern into the video stream, video copy detection techniques match content-based signatures to detect copies of video. Existing typical content-based copy detection schemes have relied on image matching which is based on key frame detection. This paper proposes a motion directional histogram, which is quantized and accumulated the direction of motion, for video copy detection. The video clip is represented by a motion directional histogram as a 1-dimensional graph. This method is suitable for real time indexing and counting the TV CF verification that is high motion video clips.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.16 no.5 s.96
• /
• pp.534-540
• /
• 2005

This paper analyzes the correlations between the impedance matching of the antenna and the radiation characteristics of the mobile handset body. Using two kinds of mobile handset which has retractable and fixed antenna the impedance and radiation pattern is measured under totally 16 conditions. By measured results, it has been identified that the radiation energy into human head can be reduced by attaining the better impedance matching when the radiation pattern out of the mobile handset is like the ideal monopole antenna.

• KIISE Transactions on Computing Practices
• /
• v.23 no.3
• /
• pp.165-170
• /
• 2017

Many studies have utilized GPGPU (General-Purpose Graphic Processing Unit) and its high computing power to compute complex tasks. The characteristics of GPGPU programs necessitate the operations of memory copy between the host and device. A high latency period can affect the performance of the program. Thus, it is required to significantly improve the performance of GPGPU programs by optimizations. By executing multiple GPGPU programs simultaneously, the latency hiding effect of memory copy is achieved by overlapping the memory copy and computing operations in GPGPU. This paper presents the results of analyzing the latency hiding effect for memory copy operations. Furthermore, we propose a performance anticipation model and an algorithm for the limitations of using pinned memory, and show that the use of the proposed algorithm results in a 41% performance increase.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.12 no.3
• /
• pp.71-74
• /
• 2012

We have manufactured a close range Dicke type radiometer which consists of two stage low noise amplifier and diode detector. Frequency range of this system is 35 GHz. And this is used for studying temperature calibration on specific objects. We have present millimeter-wave radiometer's thermal calibration method and its characteristics. From absolute temperature 299K to 309K, in proportion to increase temperature, output voltages are linearly increased. In this case, undefined objects can be measured thermal noise temperature relatively. Overall from absolute temperature 214K to 309K, we have obtained relation of temperature and output voltage;V= 0.03601K - 10.70517.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.19 no.3
• /
• pp.515-522
• /
• 1994

The radiation characteristics of the conical corrugated feed horn are analyzed by the Gaussian beam mode theory. the electric field over the aperture can be expanded in terms of a set of Gaussian-Laguerre modes. It is proved that these modes are the solutions of the wave epuations for the paraxial approximation. A method, using the sum of the mode expansion coefficients instead of calculation only the fundamental mode, is presented in order to reduce the radiation pattern error. For illustrative examples, the radiation patterns of the corrugated horn antenna operting over C, Ku, and mm-wave band are calculated. Our results agree well with the results obtained by the vector potential method over each band, and also agree well with the measured value at 6.175GHz.

• Fire Science and Engineering
• /
• v.21 no.4
• /
• pp.18-24
• /
• 2007

The purpose of this study is focussed on the numerical predictions of temperature distribution by radiation heat transfer in atrium fire using the field fire model and the CCRHT-3D code. This code uses standard $k-{\varepsilon}$ turbulent model with SIMPLE algorithm and weighted sum of gray gases model regrouping(WSGGM-RG). The WSGGM-RG calculates radiative properties on the reduced computational loads while reserving the accuracy. The numerical results show that lower temperature distributions on the wall and the top ceiling wall can be obtained by considering radiative heat transfer. The temperature on the top ceiling wall can be an important parameter in predicting the operating condition of the sprinkler head.

• Journal of Science Education
• /
• v.47 no.1
• /
• pp.52-62
• /
• 2023

This study examines how prospective earth science teachers perceive the concept of "equilibrium" and "interaction between Earth's spheres" in understanding Earth's radiative equilibrium and tries to identify their misconceptions. For this purpose, a questionnaire was designed and put to them to look into their thought flow based on the items that appeared in the national level evaluation. As a result of analyzing their answers, even though all the prospective teachers correctly described the concept of radiative equilibrium, about 90% of them did not apply the concept of radiative equilibrium to the new environment of the Earth without atmosphere. They do not seem to be able to smoothly derive the concept of a new 'interaction' between the changed regions and a new 'equilibrium' that will be reached over a long period of time. In this respect, it is likely that the textbooks had some influence on the formation of their concepts. In particular, high school Earth Science textbooks describe the Earth's radiation equilibrium in a quantitative manner, focusing on the heat budget of the equilibrium state rather than the process of reaching radiation equilibrium. Such an approach of textbooks might be an obstacle to fostering students into creative convergence-type talents pursued in the 2015 revised curriculum. Meanwhile, in order to eliminate the misconceptions of students often found in the understanding of Earth's radiation equilibrium, this study suggests that the core concepts need to be dealt with more attention even in college courses for training prospective teachers.

• Journal of KIISE:Computer Systems and Theory
• /
• v.27 no.9
• /
• pp.793-802
• /
• 2000

본 논문에서는 분산 공유 메모리(distributed shared memory) 시스템에서 데이터의 일치성(consistency)을 마감시간(deadline) 이내에 완료하기 위해서 새로운 실시간 프로토콜을 제안한다. 분산 공유 메모리 시스템에서 사용되는 공유 데이터는 여러 시스템에 복제를 할 수 있기 때문에 이들간 일치성을 효과적으로 유지시키기 위한 여러 방법이 연구되어 왔다. 기존의 방법들은 평균 액세스 비용을 단축시키기 위한 것이고 프로토콜에 따라 서로 다른 복사본의 개수를 갖게 되며 일치성 유지를 위한 비용은 시스템이 갖고 있는 복사본의 개수에 따라 증가한다. 각 노드가 서로 다른 데드라인을 갖는 실시간 분산시스템에서는 일치성 유지를 주어진 데드라인이내에 완료하기 위해서는 일치성 유지를 위한 비용을 줄이는 것도 요구되지만 데드라인이 상대적으로 급한 노드에 대한 우선적인 처리가 요구된다. 실시간 프로토콜에서는 각 분산 시스템에서 데드라인이 상대적으로 급한 노드가 항시 복사본을 갖게 하고 전체 복사본의 개수를 제한한다. 시뮬레이션을 통해서 실시간 프로토콜의 성능향상을 확인하였다.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.19 no.2
• /
• pp.7-13
• /
• 1982

In this Paper, the radiation Patterns of long wire antennas are computed by applying Dyadic Green's Function to the propagation vector, This result is used to analyze the polarized radiation patterns for the various geometrical structures of the bent dipole antennas. When the ratio of the vertical portion over the total length of the bent dipole antenna is 0.4major angle and axail ratio are changed most sensitively for the azimuth rotation, and the radiation field propagates strongly perpendicular to the bent antenna plane.

• Fire Science and Engineering
• /
• v.28 no.3
• /
• pp.20-28
• /
• 2014

Effect of radiation models on the suppression limits in counterflow $CH_4$/air diffusion flame was numerically investigated with fundamental experiments for the numerical validation. $N_2$ and $CO_2$ were considered as extinguishing agents. The differences in extinguishing concentration between OTM and SNB radiation models which have different accuracy levels were examined. As a result, there is no considerable difference in extinguishing concentration for the $N_2$ dilution as the radiation models with different accuracy levels were used. As the $CO_2$ having strong radiative effect was diluted in the low strain flames, however, the radiation model with high predictive accuracy such as SNB should be used. In particular, the $CO_2$ dilution in fuel stream leads to the significant difference in extinguishing concentration between OTM and SNB models. Therefore, it is necessary that the radiation model should be reasonably chosen with the consideration of numerical accuracy and computational time for the prediction of extinguishing concentration.