• 한국응용과학기술학회지
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• 제22권4호
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• pp.299-305
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• 2005

In this study, we designed color of tunable and high efficient organic materials using the quantum dynamics and the semi-empirical calculation, and applied this results to the fabrication of organic light-emitting diodes. Also we optimized the molecular structure of phosphorescent materials and the energy transfer from a host to a dye which makes organic light-emitting diodes improve. Using quantum dynamics method, the molecular structures of ligand only and the whole metal chelate were optimized, and these energy levels were calculated. From this test results, we could understand the emission mechanism of phosphors with various ligands as well as design the proper ligands reducing the T-T annihilation and the carrier lifetime. We also could design ligands with various colors using this test method.

• 반도체디스플레이기술학회지
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• 제17권4호
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• pp.91-96
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• 2018

In this study temperature distribution and gas flow inside a planetary type reactor in which a number of satellites on a spinning susceptor were rotating were analyzed using numerical simulation. Effects of flow rates on gas flow and temperature distribution were investigated in order to obtain design parameters. The commercial computational fluid dynamics software CFD-ACE+ was used in this study. The multiple-frame-of-reference was used to solve continuity, momentum and energy conservation equations which governed the transport phenomena inside the reactor. Kinetic theory was used to describe the physical properties of gas mixture. Effects of the rotation speed of the satellites was clearly seen when the inlet flow rate was small. Thickness of the boundary layer affected by the satellites rotation became very thin as the flow rate increased. The temperature field was little affected by the incoming flow rate of precursors.

• International Journal of Advanced Culture Technology
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• 제8권4호
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• pp.299-305
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• 2020

With the advancement of the 4th Industrial Revolution(4IR), microprocessor education is on the rise due to the explosive demand for IoT (Internet of Things) and M2M devices. However, it is difficult due to many constraints to efficiently transfer training on hardware assembly and implementation through online training. Thus, we developed a cost-effective online content based on Arduino simulations, Atmel Studio 7, and WinAvr simulator that are required for the utilization of AVR 128. These Camtasia videos overcame the limitation of theory focused on-line education by visually introducing the practical utilization of an actual AVR 128. In this paper, the proposed educational content was provided to university students, and the results of student feedback show that it has a strong effect.

• 전자공학회논문지D
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• 제36D권11호
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• pp.18-26
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• 1999

최근, 유사 빔 전파방법이나 비 직교성 결합모드이론과 같은 다양한 근시적 해석법들이 중첩모드에 기초한 테이퍼 방향성 결합기의 그 광학적 특성을 분석하기 위하여 제안되어 왔다. 비록, 이들 접근 방식들이 특별한 구조에서 충분히 정확한 결과들을 제공하지만 테이퍼 전송 구조와 같은 민감한 광 소자 해석에는 불충분하다. 이를 위하여, 우리는 그 방향성 결합기의 전력전송을 정확하게 해석하기 위하여 새롭게 발전된 모드 전송선로, 해석법을 소개하고 이용하고자 한다. 이를 이용한 수치 해석 결과 대칭인 두 테이퍼 채널의 간격이 증가함에 따라 우/기 모드의 전파상수는 하나의 값으로 수렴하였다. 더욱이, 테이퍼 각도가 ${\theta}=0.1^{\circ}$일 때 하나의 전송 채널을 통하여 입사된 모드의 97%가 다른 전송 채널로 전송되었고, 그 기운 각도가 증가함에 따라 전력 전송은 현저하게 감소하였다.

• Bulletin of the Korean Chemical Society
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• 제31권4호
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• pp.934-940
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• 2010

The reduction of [$Os_3(CO)_{11}P(OMe)_3$] and subsequent ionic coupling of the reduced species with $[Ru({\eta}^5-C_5H_5)(CH_3CN)_3]^+$ resulted in the formation of [$Os_3(CO)_{11}P(OMe)_3(Ru({\eta}^5-C_5H_5))_2$] which can be converted to spiked tetrahedral cluster, [$HOs_3(CO)_{11}P(OMe)_3Ru_2({\eta}^5-C_5H_5)(C_5H_4)$] via the intramolecular hydrogen transfer. Due to the unavailability of a suitable single crystal, the PW91/SDD and LDA/SDD density functional methods were used to predict possible structures and the available spectroscopic information (IR, NMR) of [$Os_3(CO)_{11}P(OMe)_3(Ru({\eta}^5-C_5H_5))_2$]. The most probable geometry found by constrained search is the isomer (a2) in which the phosphite, $P(OMe)_3$, occupies an axial position on one of the two osmium atoms that is edge bridged by the $Ru(CO)_2({\eta}^5-C_5H_5)$ unit. By using the most probably geometry, the predicted infrared frequencies and $^1H$, $^{13}C$ and $^{31}P$ NMR chemical shifts of the compound are in the same range as the experimental values. For this type of complex, the LDA/SDD method is appropriate for IR predictions whereas the OPBE/IGLO-II method is appropriate for NMR predictions. The activation energy and reaction energy of the intramolecular hydrogen transfer coupled with the structural change of the transition metal framework were estimated at the PW91/SDD level to be 110.32 and -0.14 kcal/mol respectively.

• 한국생산제조학회지
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• 제22권6호
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• pp.931-936
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• 2013

Recently, the use of large-electron-beam polishing for polishing complex metal surfaces has been proposed. In this study, the temperature induced by a large electron beam was predicted using the heat transfer theory. A finite element (FE) model of a continuous wave (CW) electron beam was constructed assuming Gaussian distribution. The temperature distribution and melting depth of an SUS304 sample were predicted by changing electron-beam polishing process parameters such as energy density and beam velocity. The results obtained using the developed FE model were compared with experimental results for verifying the melting depth prediction capability of the developed FE model.

• 기술혁신학회지
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• 제9권3호
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• pp.578-605
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• 2006

이 논문은 과학기술 영역에서의 행정규제 문제, 특히 과학기술행정의 중요수단인 국가연구개발사업 등으로 발생된 공공기술 관리에 관한 규제제도의 적정성 문제를 살펴보는 데 있다. 주요내용은 현행 규제제도가 법치주의 또는 규제법원리의 관점에서 적절하게 규정되어 있으며, 또한 해외사례와의 비교 및 제도운영상 개선할 점은 없는지에 대하여 체계적으로 파악해 보는데 중점을 두었다. 이를 위해 공공기술 관리 규제에 관한 법체계와 내용을 간략히 살펴본 다음, 현행 규제제도의 적정성 및 타당성을 규제의 입법형식, 규제의 내용, 규제 기준 및 규제위반에 대한 제재의 문제로 구분하여 분석 평가하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권2호
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• pp.483-503
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• 2014

In this paper, human action recognition using pyramid histograms of oriented gradients and collaborative multi-task learning is proposed. First, we accumulate global activities and construct motion history image (MHI) for both RGB and depth channels respectively to encode the dynamics of one action in different modalities, and then different action descriptors are extracted from depth and RGB MHI to represent global textual and structural characteristics of these actions. Specially, average value in hierarchical block, GIST and pyramid histograms of oriented gradients descriptors are employed to represent human motion. To demonstrate the superiority of the proposed method, we evaluate them by KNN, SVM with linear and RBF kernels, SRC and CRC models on DHA dataset, the well-known dataset for human action recognition. Large scale experimental results show our descriptors are robust, stable and efficient, and outperform the state-of-the-art methods. In addition, we investigate the performance of our descriptors further by combining these descriptors on DHA dataset, and observe that the performances of combined descriptors are much better than just using only sole descriptor. With multimodal features, we also propose a collaborative multi-task learning method for model learning and inference based on transfer learning theory. The main contributions lie in four aspects: 1) the proposed encoding the scheme can filter the stationary part of human body and reduce noise interference; 2) different kind of features and models are assessed, and the neighbor gradients information and pyramid layers are very helpful for representing these actions; 3) The proposed model can fuse the features from different modalities regardless of the sensor types, the ranges of the value, and the dimensions of different features; 4) The latent common knowledge among different modalities can be discovered by transfer learning to boost the performance.

• Current Optics and Photonics
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• 제8권1호
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• pp.97-104
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• 2024

In aerial cameras, image quality is easily affected by weather, temperature, and the attitude of the aircraft. Aiming at this phenomenon, based on the theory of two-step zoom optical systems, a dual-band optical-despun two-step zoom optical system is designed. The system has a small field of view of 2.00° × 1.60°, and a large field of view of 4.00° × 3.20°. In the zoom process, the wavelength range is 0.45-0.70 ㎛ and 0.75-1.10 ㎛, and the size of the optical system is 168 mm (L) × 90 mm (W) × 60 mm (H). The overall lens weight is only 170.8 g, which has advantages for miniaturization and light weight. At the Nyquist frequency of 104 lp/mm, the modulation transfer function of the visible-light optical system is more than 0.44, and that of the near-infrared optical system is more than 0.30, both of which have good imaging quality and tolerance characteristics in the range of -45 to 60 ℃.

• Bulletin of the Korean Chemical Society
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• 제31권7호
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• pp.1920-1926
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• 2010

Yoon et $al.^1$ presented an approximate mathmatical model to describe ammonia removal from an experimental batch reactor system with gaseous headspace. The development of the model was initially based on assuming instantaneous equilibrium between ammonia in the aqueous and gas phases. In the model, a "saturation factor, $\beta$" was defined as a constant and used to check whether the equilibrium assumption was appropriate. The authors used the trends established by the estimated $\beta$ values to conclude that the equilibrium assumption was not valid. The authors presented valuable experimental results obtained using a carefully designed system and the model used to analyze the results accounted for the following effects: speciation of ammonia between $NH_3$ and $NH^+_4$ as a function of pH; temperature dependence of the reactions constants; and air flow rate. In this article, an alternative model based on the exact solution of the governing mass-balance differential equations was developed and used to describe ammonia removal without relying on the use of the saturation factor. The modified model was also extended to mathematically describe the pH dependence of the ammonia removal rate, in addition to accounting for the speciation of ammonia, temperature dependence of reactions constants, and air flow rate. The modified model was used to extend the analysis of the original experimental data presented by Yoon et $al.^1$ and the results matched the theory in an excellent manner.