• 한국기술혁신학회:학술대회논문집
• /
• 한국기술혁신학회 2005년도 춘계학술대회
• /
• pp.46-59
• /
• 2005

After the IMF jurisdiction period, the Korean economy experienced a venture boom. Korean venture enterprises had been recognized that high profitable and high technology capacity based. These ventures also have contributed to national added value tolerably. In particular, Korean information technology (IT) venture companies got away the order of economy concentrated big companies, which were taken the opportunity of new economy to make suggestion of the future courses and to open an e-Korea era. However, IT ventures firms or dotcom enterprises have had difficulties through sinking down their bubbles and slumping technology sector from the first half of the 2000. In consideration of Korea IT venture companies' conditions, Korean government introduce new national vision in order to go ahead of intelligence based society form knowledge based. Korea is planning new investment to meet with the challenge of globalization proactively by national band named u-Korea. As following a step in IT infrastructure, it will give Korean IT ventures new demand creative technologies and services by new technological windows of opportunity. This situation is expected that will become an economic take-off. This paper will look for the way to stimulate Korean IT ventures' competence and present new frontier of IT ventures turnaround.

• Bulletin of the Korean Chemical Society
• /
• 제35권4호
• /
• pp.1105-1109
• /
• 2014

While single strand DNAs have been widely used for the scaffold of brightly fluorescent silver nanoclusters (Ag NCs), double strand DNAs have not been as successful. Herein, we report a novel synthetic approach for bright Ag NCs using branched double strand DNAs as the scaffolds for synthesis. X-shaped DNA (X-DNA) and Y-shaped DNA (Y-DNA) effectively stabilized Ag NCs, and both X-DNA and Y-DNA resulted in brightly fluorescent Ag NCs. The concentration and molar ratio of silver and DNA were found important for the fluorescence efficiency. The brightest Ag NC with the photoluminescence quantum efficiency of 19.8% was obtained for the reaction condition of 10 ${\mu}M$ X-DNA, 70 ${\mu}M$ silver, and the reaction time of 48 h. The fluorescence lifetime was about 2 ns for the Ag NCs and was also slightly dependent on the synthetic condition. Addition of Cu ions at the Ag NC preparations resulted in the quenching of Ag NC fluorescence, which was different to the brightening cases of single strand DNA stabilized Ag NCs.

• Steel and Composite Structures
• /
• 제49권5호
• /
• pp.547-570
• /
• 2023

In the present work, a comparative study has been carried out between power, exponential, and sigmoidal sandwich FGM plates for free vibration conditions under hygro-thermal conditions. Rules of mixture is used to determine effective material properties across the thickness for power-law and sigmoid sandwich FGM plates. Exponential law is used to plot effective material properties for exponentially graded sandwich FGM plates. Temperature and moisture dependent material properties were used during the analysis. Free vibration analysis is carried out using recently proposed finite element based HOZT. Present formulation satisfies interlayer transverse stress continuity conditions at interfaces and transverse shear stress-free conditions at the plate's top and bottom surfaces. The present model is free from any penalty or post-processing requirements. Several new results are reported in the present work, especially for unsymmetric sandwich FGM plates and exponential and sigmoidal sandwich FGM plates.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제18권6호
• /
• pp.1431-1448
• /
• 2024

Complexity science is a new stage in the development of systems science that is the frontier areas of contemporary scientific development. Complexity science takes complex systems as the research object, which has attracted widespread attention from researchers in the fields of economy, control, management, and society. In recent years, with the rapid development of science and technology and people's deepening understanding for the theory of complex systems, the systems are no longer an object with a single function, but the systems are composed of multiple individuals with autonomous capabilities through cooperative and cooperation, namely multi-agent system (MAS). Currently, MAS is one of the main models for studying such complex systems. The intelligent control is to break the traditional multi-agent fault-tolerant control (FTC) concept and produce a new type of compensation mechanism. In this paper, the applications of fault-tolerant control methods for MASs are presented, and a discussion is given about development and challenges in this field.

• Advances in nano research
• /
• 제2권4호
• /
• pp.211-217
• /
• 2014

The self-assembled strain-induced sub-micrometric islands and nanostructures are grown from In-As-Sb-P quaternary liquid phase on InAs (100) substrates in Stranski-Krastanow growth mode. Two samples are under consideration. The first sample consists of unencapsulated islands and lens-shape quantum dots (QDs) grown from expressly inhomogeneous liquid phase. The second sample is an n-InAs/p-InAsSbP heterostructure with QDs embedded in the p-n junction interface. The morphology, size and shape of the structures are investigated by high-resolution scanning electron (SEM) and transmission electron (TEM) microscopy. It is shown that islands, as they decrease in size, undergo shape transitions. Particularly, as the volume decreases, the following succession of shape transitions are detected: sub-micrometric truncated pyramid, {111} facetted pyramid, {111} and partially {105} facetted pyramid, completely unfacetted "pre-pyramid", hemisphere, lens-shaped QD, which then evolves again to nano-pyramid. A critical size of $5{\pm}2nm$ for the shape transformation of InAsSbP-based lens-shaped QD to nano-pyramid is experimentally measured and theoretically evaluated.

• Nuclear Engineering and Technology
• /
• 제51권1호
• /
• pp.325-336
• /
• 2019

The activity concentrations of $^{226}Ra$, $^{232}Th$, and $^{40}K$ from 102 building materials samples were determined using a high-purity germanium (HPGe) detector. The activity concentrations were evaluated for possible radiological hazards to the human health. The excess lifetime cancer risks (ELCR) were also estimated, and the average values were recorded as $0.42{\pm}0.24{\times}10^{-3}$, $3.22{\pm}1.83{\times}10^{-3}$, and $3.65{\pm}1.85{\times}10^{-3}$ for outdoor, indoor, and total ELCR respectively. The activity concentrations were further subjected to RESRAD-BUILD computer code to evaluate the long-term radiation exposure to a dweller. The indoor doses were assessed from zero up to 70 years. The simulation results were $92{\pm}59$, $689{\pm}566$, and $782{\pm}569{\mu}Sv\;y^{-1}$ for indoor external, internal, and total effective dose equivalent (TEDE) respectively. The results reported were all below the recommended maximum values. Therefore, the radiological hazards attributed to building materials under study are negligible.

• Advances in materials Research
• /
• 제12권1호
• /
• pp.43-65
• /
• 2023

Free vibration analysis of power law and sigmoidal sandwich plates made up of functionally graded materials (FGMs) has been carried out using finite element based higher-order zigzag theory. The present model satisfies all-important conditions such as transverse shear stress-free conditions at the plate's top and bottom surface along with continuity condition for transverse stresses at the interface. A Nine-noded C0 finite element having eleven degrees of freedom per node is used during the study. The present model is free from the requirement of any penalty function or post-processing technique and hence is computationally efficient. The present model's effectiveness is demonstrated by comparing the present results with available results in the literature. Several new results have been proposed in the present work, which will serve as a benchmark for future works. It has been observed that the material variation law, power-law exponent, skew angle, and boundary condition of the plate widely determines the free vibration behavior of sandwich functionally graded (FG) plate.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제17권11호
• /
• pp.3204-3217
• /
• 2023

In this paper, the downlink of the multicast based spatial modulation systems is investigated. Specifically, physical layer multicasting is introduced to increase the number of access users and to improve the communication rate of the spatial modulation system in which only single radio frequency chain is activated in each transmission. To minimize the bit error rate (BER) of the multicast based spatial modulation system, a joint optimizing algorithm of antenna selection and multicast precoding is proposed. Firstly, the joint optimization is transformed into a mixed-integer non-linear program based on single-stage reformulation. Then, a novel iterative algorithm based on the idea of branch and bound is proposed to obtain the quasioptimal solution. Furthermore, in order to balance the performance and time complexity, a low-complexity deflation algorithm based on the successive convex approximation is proposed which can obtain a sub-optimal solution. Finally, numerical results are showed that the convergence of our proposed iterative algorithm is between 10 and 15 iterations and the signal-to-noise-ratio (SNR) of the iterative algorithm is 1-2dB lower than the exhaustive search based algorithm under the same BER accuracy conditions.

• Computers and Concrete
• /
• 제33권3호
• /
• pp.275-284
• /
• 2024

This work presents a comprehensive investigation of buckling behavior of bidirectional functionally graded imperfect beams exposed to several thermal loading with general boundary conditions. The nonlinear governing equations are derived based on 2D shear deformation theory together with Von Karman strain-displacement relation. The beams are composed of two different materials. Its properties are porosity-dependent and are continuously distributed over the length and thickness of the beams following a defined law. The resulting equations are solved analytically in order to determine the thermal buckling characteristics of BDFG porous beams. The precision of the current solution and its accuracy have been proven by comparison with works previously published. Numerical examples are presented to explore the effects of the thermal loading, the elastic foundation parameters, the porosity distribution, the grading indexes and others factors on the nonlinear thermal buckling of bidirectional FG beam rested on elastic foundation.

• 한국농림기상학회지
• /
• 제20권4호
• /
• pp.305-312
• /
• 2018

기후변화에 대한 논의가 지속되면서 다양한 영역에서 이와 관련된 연구가 진행되고 있다. 농업은 기후와 가장 밀접하게 관련된 산업으로, 기후변화와 그에 따른 이상기후에 의해 생산성이 크게 달라질 수 있다. 본 연구에서는 기후변화 및 이상기후에 따른 작목별 농산물의 생산성 변화를 살펴보고, 이상기후 종류별 발효횟수가 증가함에 따라 비효율성이 증가하는 작목을 분류하였다. 이상기후를 대리할 수 있는 자료로 기상청에서 발표하는 기상특보의 발효횟수를 활용하였고, 분석에 고려된 기상특보의 종류에는 강풍특보, 호우특보, 대설특보, 건조특보, 한파특보, 태풍특보, 폭염특보가 있다. 8개 과수 작목의 생산 효율성 대해 각 기상특보의 발효횟수가 미치는 영향을 확률적 프런티어 분석을 통해 살펴본 결과 한파특보와 대설특보가 많은 수의 과수작목에 부정적인 영향을 미치는 것으로 나타났다. 농촌진흥청의 농산물 소득조사 자료를 활용한 상기 분석결과는 기후변화와 다양한 이상기후에 대한 국내 농업의 대응전략을 효율적으로 수립하는 데 기초자료로써 활용될 수 있다고 판단된다.