• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12A
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• pp.1034-1043
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• 2011

As an introduction of an open spectrum allocation approach with technology and service neutrality is expected as a way to solve problems of frequency shortage due to the expansion of demand for wireless multimedia communications, recently, the new management model of interferences and its standard setting are required. In this paper, as a model for this new interference management considering several candidates, Block Edge Mask(BEM) approach is chosen as the most appropriate model. And to investigate the effects of interference resulting from the standard setting of BEM, assuming the use of LTE systems in the Digital Dividend, BEM out-of-band baseline in the boundaries between digital terrestrial television (DTV) service and LTE mobile communications services which are heterogeneous systems for analysis is derived and the effect of setting guard band is analyzed.

• Journal of Satellite, Information and Communications
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• v.9 no.4
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• pp.38-41
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• 2014

Due to the diversity of device performances and the possibility of providing multimedia service through many networks, media consumption environment has been changed in various ways. In recent, mobile services and broadcasting services started to provided through IP network. According to this flow changes, there was great demand for various multimedia services through heterogenous networks. To solve this problem, MMT was suggested as a standard of multimedia transport which replaces MPEG-2 TS(Transport Stream) which is used for HD(High Definition) transport. MMT can be provided various broadcasting based on IP through terrestrial, satellite, cable broadcasting networks, and also deliver multimedia through many networks at the same time. MMT was risen as a method of servicing UHD broadcasting. In this paper, we present an implementation of service architecture for hierarchical UHD broadcasting over heterogenous networks using MMT.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.11
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• pp.2091-2096
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• 2008

Due to the improvement of mobile device capabilities, a demand for various contents service is increasing. But the differences from heterogeneous mobile devices force to develop contents which is dependent on a mobile. To solve this problem, adaptation course that reorganize contents by the device capability is hooded. In this course, device description is described using device description language but there are some problems that is absence of device description repository and the way to get device description data. In this paper, I suggest device description acquisition module and define the interfaces to access device description repository that I designed and implemented.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.5
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• pp.71-77
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• 2021

Recently, there is a demand for efficient program development of an IoT application support frameworks considering heterogeneous hardware characteristics. In addition, the scope of hardware support is expanding with the development of neuromorphic architecture that mimics the human brain to learn on their own and enables autonomous computing. However, most existing IoT IDE(Integrated Development Environment), it is difficult to support AI(Artificial Intelligence) or to support services combined with various hardware such as neuromorphic architectures. In this paper, we design an AI component abstract model that supports the second-generation ANN(Artificial Neural Network) and the third-generation SNN(Spiking Neural Network), and implemented an autonomous IoT IDE based on the proposed model. IoT developers can automatically create AI components through the proposed technique without knowledge of AI and SNN. The proposed technique is flexible in code conversion according to runtime, so development productivity is high. Through experimentation of the proposed method, it was confirmed that the conversion delay time due to the VCL(Virtual Component Layer) may occur, but the difference is not significant.

• Journal of Microbiology and Biotechnology
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• v.29 no.4
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• pp.577-586
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• 2019

The engineered Aspergillus oryzae has a high NADPH demand for xylose utilization and overproduction of target metabolites. Glucose-6-phosphate dehydrogenase (G6PDH, E.C. 1.1.1.49) is one of two key enzymes in the oxidative part of the pentose phosphate pathway, and is also the main enzyme involved in NADPH regeneration. The open reading frame and cDNA of the putative A. oryzae G6PDH (AoG6PDH) were obtained, followed by heterogeneous expression in Escherichia coli and purification as a his6-tagged protein. The purified protein was characterized to be in possession of G6PDH activity with a molecular mass of 118.0 kDa. The enzyme displayed maximal activity at pH 7.5 and the optimal temperature was $50^{\circ}C$. This enzyme also had a half-life of 33.3 min at $40^{\circ}C$. Kinetics assay showed that AoG6PDH was strictly dependent on $NADP^+$ ($K_m=6.3{\mu}M$, $k_{cat}=1000.0s^{-1}$, $k_{cat}/K_m=158.7s^{-1}{\cdot}{\mu}M^{-1}$) as cofactor. The $K_m$ and $k_{cat}/K_m$ values of glucose-6-phosphate were $109.7s^{-1}{\cdot}{\mu}M^{-1}$ and $9.1s^{-1}{\cdot}{\mu}M^{-1}$ respectively. Initial velocity and product inhibition analyses indicated the catalytic reaction followed a two-substrate, steady-state, ordered BiBi mechanism, where $NADP^+$ was the first substrate bound to the enzyme and NADPH was the second product released from the catalytic complex. The established kinetic model could be applied in further regulation of the pentose phosphate pathway and NADPH regeneration of A. oryzae to improve its xylose utilization and yields of valued metabolites.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.6
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• pp.1309-1317
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• 2018

Although the IoT market is steadily growing, there is still a lack of consideration for increasing security threats in the IoT environment. In particular, it is difficult to apply existing IP security technology to resource-constrained devices. Therefore, there is a demand for reliable end-to-end communication security measures to cope with security threats such as information tampering and leakage that may occur during communication between heterogeneous networks do. In this paper, we propose an end-to-end message security protocol based on lightweight cipher that increases security and lowers security overhead in resource-constrained IoT device communication. Through simulation of processing time, we verified that the proposed protocol has better performance than the existing AES-based protocol.

• The Journal of the Korea Contents Association
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• v.21 no.6
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• pp.552-560
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• 2021

With the recent development of the art distribution system, interest in art investment is increasing rather than seeing art as an object of aesthetic utility. Unlike stocks and bonds, the price of artworks has a heterogeneous characteristic that is determined by reflecting both objective and subjective factors, so the uncertainty in price prediction is high. In this study, we used LSTM Recurrent Neural Network deep learning model to predict the auction winning price by inputting the artist, physical and sales charateristics of the Korean artist. According to the result, the RMSE value, which explains the difference between the predicted and actual price by model, was 0.064. Painter Lee Dae Won had the highest predictive power, and Lee Joong Seop had the lowest. The results suggest the art market becomes more active as investment goods and demand for auction winning price increases.

• Journal of Korea Trade
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• v.23 no.8
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• pp.1-26
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• 2019

Purpose - This paper investigates the recent trade collapse, recovery, and prolonged slowdown to shed light on the discussions about whether the current slowdown is structural or cyclical. I examine structural, cyclical, and heterogeneous aspects of the recent trade trends using detailed statistics of a small open economy, South Korea, whose economic success and growth have been heavily dependent on exports. Design/methodology - I use both aggregated and disaggregated trade statistics of South Korea. I apply the following methodologies: 1) I decompose the trade growth into the extensive and the intensive margin and observe the effect of prices over time. 2) I estimate the trade-income elasticities focusing on the world's import demand, separately for goods from the world and from Korea. 3) I compare the drop in goods exports in slowdown and trade collapse, which are the two unusual periods in the recent history when world trade has substantially dropped altogether. Findings - I show that while the last drop of trade after 2015 has cyclical aspects, there is evidence that the continued slowdown from 2012 is structural: 1) the so-called 'China factor' is found in the analysis of trade-income elasticity of the world and China for imports from Korea. 2) The bilateral trade barriers between Korea and its principal trading partners are universally tightening. 3) Firm sizes, destination countries, and the mode of transactions affect disaggregated trade flows during the slowdown periods. Originality/value - This paper contributes to the debate regarding whether the current trade slowdown is structural or cyclical. I provide two concrete evidence that the export drop in 2015 stems from low oil prices: one is the divergence of Korean export value index from its export quantity index, which started in late 2014 when oil prices plunged. I also contribute to the literature by providing evidence that Korea's trade barriers with important trading partners are steadily increasing since 2012 as the protectionist measures toward Korea's export products are steeply increasing after the global financial crisis.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.4
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• pp.1147-1161
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• 2023

The Internet of Things (IoT) requires a new processing model that will allow scalability in cloud computing while reducing time delay caused by data transmission within a network. Such a model can be achieved by using resources that are closer to the user, i.e., by relying on edge computing (EC). The amount of IoT data also grows with an increase in the number of IoT devices. However, building such a flexible model within a heterogeneous environment is difficult in terms of resources. Moreover, the increasing demand for IoT services necessitates shortening time delay and response time by achieving effective load balancing. IoT devices are expected to generate huge amounts of data within a short amount of time. They will be dynamically deployed, and IoT services will be provided to EC devices or cloud servers to minimize resource costs while meeting the latency and quality of service (QoS) constraints of IoT applications when IoT devices are at the endpoint. EC is an emerging solution to the data processing problem in IoT. In this study, we improve the load balancing process and distribute resources fairly to tasks, which, in turn, will improve QoS in cloud and reduce processing time, and consequently, response time.

• Korean Journal of Materials Research
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• v.32 no.2
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• pp.98-106
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• 2022

Metal-organic frameworks (MOFs) are widely used in various fields because they make it easy to control porous structures according to combinations of metal ions and organic linkers. In addition, ZIF (zeolitic imidazolate framework), a type of MOF, is made up of transition metal ions such as Co²⁺ or Zn²⁺ and linkers such as imidazole or imidazole derivatives. ZIF-67, composed of Co²⁺ and 2-methyl imidazole, exhibits both chemical stability and catalytic activity. Recently, due to increasing need for energy technology and carbon-neutral policies, catalysis applications have attracted tremendous research attention. Moreover, demand is increasing for material development in the electrocatalytic water splitting and metal-air battery fields; there is also a need for bifunctional catalysts capable of both oxidation/reduction reactions. This review summarizes recent progress of bifunctional catalysts for electrocatalytic water splitting and metal-air batteries using ZIF-67. In particular, the field is classified into areas of thermal decomposition, introduction of heterogeneous elements, and complex formation with carbon-based materials or polyacrylonitrile. This review also focuses on synthetic methods and performance evaluation.