Structure of technology evolution: The way on which ICT industry emerged in Korea

The role of ICT in the economic growth in Korea is a great attraction to the telecommunication society interested in the relationship among ICT, innovation policy and economic growth. However, prior research concentrates on investigating the effect of policy on innovation and economic growth, but misses the mechanism how a policy affects the technological system which interacts with public institutes, universities and private firms. In this paper, we analyze the structure of technology evolution in Korea with empirical data of patents to understand the prosperity of ICT sector in Korea. To do so, we define a technology network, or a set of nodes and links, representing technology fields and the relations between the fields, respectively, and measure the network topology and position per year between 1970 and 2010. Our results propose that the technology network maintains the scalefree topology, but the entities of the hub positions are gradually replaced emerging entities on the invariant network topology. Our findings are expected to motivate ICT innovation studies to understand the evolutionary mechanism of ICT industry in the systematic perspective of technology, and improve the policy of ICT innovation

Structure of technology evolution

노트 : 24th European Regional Conference of the International Telecommunication Societ

Which technology diversification index should be selected?: Insights for diversification perspectives

The implacable list of diversification indices allows a wide range of selection opportunities for the researchers. The absence of consensus on the selection of suitable technology diversification index, however, may lead to a lack of objectivity with ample grounds. In this study, we focus on the case of technology diversification using patent to derive empirical implication for selecting suitable diversification index. To obtain the content validity of diversification index, three cases were tested: cross section, single and multiple time periods. As a result, diversification indices are separated into two groups: HHI, Gini-Simpson, 1/HHI, and Entropy for PC1 and Variety and Rao-Stirling for PC2. In this context, technology diversification can be explained by two perspectives of diversification: balance-centered and hetero-centered diversification. The balance-centered diversification implies the proportion of elements are the target of interest while hetero-centered diversification refers to variety and disparity of diversification, which focuses on the degree of differentiation among elements. In applicant-level technology diversification studies, these two diversification perspectives are recommended to be used. Subject classification codes: include these here if the journal requires the

Strong exciton-photon coupling in self-hybridized organic–inorganic lead halide perovskite microcavities

Controlling coherent light–matter interactions in semiconductor microcavities is at the heart of the next-generation solid-state polaritonic devices. Organic–inorganic hybrid perovskites are potential materials for room-temperature polaritonics owing to their high exciton oscillator strengths and large exciton binding energies. Herein, we report on strong exciton-photon coupling in the micro-platelet and micro-ribbon shaped methylammonium lead bromide single crystals. Owing to high crystallinity and large refractive index, the as-grown perovskite microcrystals serve as self-hybridized optical microcavities along different orientations due to their distinct physical dimensionalities. In this regard, the perovskite micro-platelet forms a simple Fabry–Perot microcavity in out-of-plane orientation, while the micro-ribbon functions as a Fabry–Perot type waveguide microcavity within the plane of the perovskite sample. Consequently, excitons in these microcavities strongly interact with their corresponding uncoupled cavity modes, yielding multimode exciton-polaritons with Rabi splitting energies ∼205 and 235 meV for micro-platelet and micro-ribbon geometry, respectively. Furthermore, micro-ribbon geometry displays Young’s double-slit-like interference patterns, which together with the numerical simulation readily reveals the parity and the mode order of the uncoupled cavity modes. Thus, our results not only shed light on strong exciton-photon coupling in various morphologies of methylammonium lead bromide microcrystals but also open an avenue for advanced polaritonic devices

Strong exciton-photon coupling in self-hybridized organic-inorganic lead halide perovskite microcavities

Controlling coherent light-matter interactions in semiconductor microcavities is at the heart of the next-generation solid-state polaritonic devices. Organic-inorganic hybrid perovskites are potential materials for room-temperature polaritonics owing to their high exciton oscillator strengths and large exciton binding energies. Herein, we report on strong exciton-photon coupling in the micro-platelet and micro-ribbon shaped methylammonium lead bromide single crystals. Owing to high crystallinity and large refractive index, the as-grown perovskite microcrystals serve as self-hybridized optical microcavities along different orientations due to their distinct physical dimensionalities. In this regard, the perovskite micro-platelet forms a simple Fabry-Perot microcavity in out-of-plane orientation, while the micro-ribbon functions as a Fabry-Perot type waveguide microcavity within the plane of the perovskite sample. Consequently, excitons in these microcavities strongly interact with their corresponding uncoupled cavity modes, yielding multimode exciton-polaritons with Rabi splitting energies ∼205 and 235 meV for micro-platelet and micro-ribbon geometry, respectively. Furthermore, micro-ribbon geometry displays Young's double-slit-like interference patterns, which together with the numerical simulation readily reveals the parity and the mode order of the uncoupled cavity modes. Thus, our results not only shed light on strong exciton-photon coupling in various morphologies of methylammonium lead bromide microcrystals but also open an avenue for advanced polaritonic devices. © 2023 the author(s), published by De Gruyter, Berlin/Boston 2023.TRU