• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제11권6호
• /
• pp.2979-2995
• /
• 2017

In recent years, there has been an increasing number of studies focused on identifying a set of spreaders to maximize the influence of spreading in complex networks. Although the k-core decomposition can effectively identify the single most influential spreader, selecting a group of nodes that has the largest k-core value as the seeds cannot increase the performance of the influence maximization because the propagation sphere of this group of nodes is overlapped. To overcome this limitation, we propose a neighborhood coreness cover and discount heuristic algorithm named "NCCDH" to identify a set of influential and decentralized seeds. Using this method, a node in the high-order shell with the largest neighborhood coreness and an uncovered status will be selected as the seed in each turn. In addition, the neighbors within the same shell layer of this seed will be covered, and the neighborhood coreness of the neighbors outside the shell layer will be discounted in the subsequent round. The experimental results show that with increases in the spreading probability, the NCCDH outperforms other algorithms in terms of the affected scale and spreading speed under the Susceptible-Infected-Recovered (SIR) and Susceptible-Infected (SI) models. Furthermore, this approach has a superior running time.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제11권10호
• /
• pp.4929-4947
• /
• 2017

In visual object tracking, Correlation Filter-based Tracking (CFT) systems have arouse recently to be the most accurate and efficient methods. The CFT's circularly shifts the larger search window to find most likely position of the target. The need of larger search window to cover both background and object make an algorithm sensitive to the background and the target occlusions. Further, the use of fixed-sized windows for training makes them incapable to handle scale variations during tracking. To address these problems, we propose two layer target representation in which both global and local appearances of the target is considered. Multiple local patches in the local layer provide robustness to the background changes and the target occlusion. The target representation is enhanced by employing additional reversed RGB channels to prevent the loss of black objects in background during tracking. The final target position is obtained by the adaptive weighted average of confidence maps from global and local layers. Furthermore, the target scale variation in tracking is handled by the statistical model, which is governed by adaptive constraints to ensure reliability and accuracy in scale estimation. The proposed structural enhancement is tested on VTBv1.0 benchmark for its accuracy and robustness.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2009년도 하계학술대회 논문집
• /
• pp.282-283
• /
• 2009

In the research, we have proposed a novel encapsulation with simple process and steady film for external environment in comparison with conventional encapsulation method. This was designed to cover the emitting organic material from air. Silicon 야oxide was used for thin film of encapsulation and the deposition thickness of the organic film was 220 nm. Operating voltage of green OLED with encapsulation was 5.5 V and luminance was 7.370 cd/$m^2$ at the applied voltage of 14.5 V. Luminance was measured in 10 hour intervals at the air-exposed condition. After 110 hours and 300 hours, luminances of green OLED were 7,368 and 7,367 cd/$m^2$, respectively. Luminance of green JLED doesn't decrease until 300 hours. As a results, proposed encapsulation can increase the life time of green OLED.

• Ocean Science Journal
• /
• 제43권2호
• /
• pp.115-126
• /
• 2008

Direct measurements of four radiative components at air-sea boundary layer were conducted in the southern Yellow Sea during three cruises (seasons) in 2007. Simultaneous observations of meteorological (cloud cover, air temperature and humidity) and oceanographic (sea surface temperature) parameters were carried out. Observational results of radiative fluxes and meteorological and oceanographic parameters are presented. Mean diurnal cycles of four radiative components, net radiation, and sea surface albedo are calculated to achieve averages in different seasons. Net radiative fluxes in three seasons (winter, spring, autumn) are 8, 146, $60\;W/m^2$, respectively. Comparisons between the observed radiative fluxes and those estimated with formulas are taken.

• Geomechanics and Engineering
• /
• 제11권4호
• /
• pp.471-492
• /
• 2016

Underground tunnelling is one of the sustainable construction methods which can facilitate the increasing passenger transportation in the urban areas and benefit the community in the long term. Tunnelling in various ground conditions requires careful consideration of the stability factor. This paper investigates three dimensional stability of a shallow circular tunnel in a layered soil. Upper bound theorem of limit analysis was utilised to solve the tunnel face stability problem. A three dimensional kinematic admissible failure mechanism was improved to model a layered soil and limiting assumptions of the previous studies were resolved. The study includes calculation of the minimum support pressure acting on the face of the excavation in closed-face excavations. The effects of the characteristics of the layers on the minimum support pressure were examined. It was found that the ratio of the thickness of cover layers particularly when a weak layer is overlying a stronger layer, has the most significant influence on the minimum tunnel support pressure. Comparisons have been made with the results of the numerical modelling using FLAC3D software. Results of the current study were in a remarkable agreement with those of numerical modelling.

• Journal of Plant Biology
• /
• 제15권1호
• /
• pp.1-12
• /
• 1972

As part of the study of the structure and the successional trends of our temperate forests, a quantitative survey was made of the relatively well conserved forest stands on Mt. Kwanak, Seoul. Three community types were observed; the Pinus densiflora-Quercus mongolica community, the Pinus densiflora community, and the Quercus mongolica community. Evidence suggests that the dominance of Pinus densiflora and quercus mongolica will continue in the Pinus densiflora-Quercus mongolica community, however, in the Pinus densiflora community the dominant species, Pinus densiflora, is now being replaced by Quercus mongolica. The trend toward an increased in Acer pseudo-sieboldianum var. koreanum, Fraxinus rhynchophylla, Carpinus cordita, and Acer mono is observed in the Quercus mongolica community. An analysis of the overall composition of the forest reveals that the upper story is mostly occupied by Quercus mongolica and Pinus densiflora, the shrub layer by Rhododendron schlippenbachii and Lespedeza maximowiczii, and the herb layer by Spodiopogon cotulifer and Artemisia keiskeana. Quercus mongolica may cover most part of the forest, gradually excluding Pinus densiflora. Acer pseudo-sieboldianum var. koreanum, Fraxinus rhynchophylla, Carpinus coradata, and Acer mono are increasing in importance with the potentiality of developing into major canopy components. With the diversification of the physical habitat Cephalotaxus koreana and Magnolia sieboldii, the species which had almost completely been eliminated form the forest through the severe interferences, have reappeared.

• 한국재료학회지
• /
• 제8권5호
• /
• pp.419-423
• /
• 1998

매립형 InGaAnP/InP 레이저 다이오드 제작을 위한 질량 이동 현상의 최적화에 대한 연구를 수행하였다. Double heterostructure 레이저 다이오드 구조의 1차 성장은 액상 에피 성장 장치를 이용하였으며, 메사 에칭하였다. 활성층을 [110] 방향으로 선택적으로 에칭 한 후, 액상 에피 성장 장치를 이용하여 질량 이동 현상을 발생시켜 매립형 구조를 형성시켰다. 질량 이동 현상의 임계온도는 40분간 유지시켰을 때 $670^{\circ}C$로 나타났으며 재현성 있게 질량 이동 현상이 발생하였다. 질량 이동 현상에 의해 성장된 층의 폭은 온도증가에 따라 약간 증가하였다.

• 한국초전도ㆍ저온공학회논문지
• /
• 제16권2호
• /
• pp.59-63
• /
• 2014

HTS power cable bypass the fault current through the former to protect superconducting tapes. On the other hand, the fault current limiting (FCL) power cable can be considered to mitigate the fault current using its increased inductance and resistance. Using the increased resistance of the cable is similar to the conventional resistive fault current limiter. In case of HTS power cable, the magnetic field of HTS power cable is mostly shielded by the induced current on the shield layer during normal operation. However, quench occurs at the shield layer and its current is kept below its critical current at the fault condition. Consequently, the magnetic field starts to spread out and it generates additional inductive impedance of the cable. The inductive impedance can be enhanced more by installing materials of high magnetic susceptibility around the HTS power cable. It is a concept of SFCL power cable. In this paper, a sample SFCL power cable is suggested and experimental results are presented to investigate the effect of iron cover on the impedance generation. The tests results are analyzed to verify the generation of the inductive and resistive impedance. The analysis results suggest the possible applications of the SFCL power cable to reduce the fault current in a real grid.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2006년도 춘계학술대회
• /
• pp.434-437
• /
• 2006

Though numerous drilling has been performed in Jeju Island for development of ground water, the wells are mostly located along the coast lines or at low altitude area, and can hardly be found on the mid-mountain area. Two-dimensional magnetotelluric (MT) surveys have been carried out to cover the lack of geological Informal ion on the mid-mountain area and to figure out any possible structures or evidences for deep geothermal energy remained. Two-dimensional (2-D) inversion of MT data for four survey lines surrounding the Halla mountain show a thick layer having around 10 ohm-m in the depth of a few hundred meters throughout the survey area, which can be considered as the unconsol idated sedimentary layer. And they also show a conductive anomaly extending to more than 2km depth at the central part of each survey lines, which can possibly be related with old volcanic activities during the formation of Halla Mt.. Further seological/geophysical investigations should be followed.

• Structural Engineering and Mechanics
• /
• 제77권5호
• /
• pp.673-689
• /
• 2021

This paper addresses the efficiency of thermal insulation layers applied to protect structural elements strengthened by fiber-reinforced polymers (FRP) in the case of fire event. The paper presents numerical modeling and nonlinear analysis of reinforced concrete (RC) columns externally strengthened by FRP and protected by thermal insulation layers when subjected to elevated temperature specified by standard fire tests, in order to predict their residual capacity and fire endurance. The adopted numerical approach uses commercial software includes heat transfer, variation of thermal and mechanical properties of concrete, steel reinforcement, FRP and insulation material with elevated temperature. The numerical results show good agreement with published results of full-scale fire tests. A parametric study was conducted to investigate the influence of several variables on the structural response and residual capacity of insulated FRP-confined columns loaded by service loads when exposed to fire. The residual capacity of FRP-confined RC column was affected by concrete grade and insulation material and was shown to improve substantially by increasing the concrete cover and insulation layer thickness. By increasing the VG insulation layer thickness 15, 32, 44, 57 mm, the loss in column capacity after 5 hours of fire was 30%, 13%, 7% and 5%, respectively. The obtained results demonstrate the validity of the presented approach for estimation of fire endurance and residual strength, as an alternative for fire testing, and for design of fire protection layers for FRP-confined RC columns.