• Journal of Information Processing Systems
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• v.16 no.1
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• pp.42-48
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• 2020

This paper proposes an operating system architecture for unmanned aerial vehicle (UAV), which is secure against root exploit, resilient to connection loss resulting in the control loss, and able to utilize common applications used in Linux. The Linux-based UAVs are exposed to root exploit. On the other hand, the microkernel-based UAVs are not able to use the common applications utilized in Linux, even though which is secure against root exploit. For this reason, the proposed architecture uses a virtualized microkernel on the Linux operating system to isolate communication roles and prevent root exploit. As a result, the suggested Operating system is secure against root exploit and is able to utilize the common applications at the same time.

• Journal of the Korea Society of Computer and Information
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• v.21 no.5
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• pp.49-56
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• 2016

Increasing Internet traffic and forwarding table size need high performance IP address lookup engine which is a crucial function of routers. For finding the longest matching prefix, trie-based or its variant schemes have been widely researched in software-based IP lookup. As a software router, we enhance the IP address lookup engine using GPU which is a device widely used in high performance applications. We propose a data structure for multibit trie to exploit GPU hardware efficiently. Also, we devise a novel scheme that the root subtrie is loaded on Shared Memory which is specialized for fast access in GPU. Since the root subtrie is accessed on every IP address lookup, its fast access improves the lookup performance. By means of the performance evaluation, our implemented GPU-based lookup engine shows 17~23 times better performance than CPU-based engine. Also, the fast access technique for the root subtrie gives 10% more improvement.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.12
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• pp.3011-3016
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• 2015

Representing protein three-dimensional structure by concatenating a sequence of protein fragments gives an efficient application in analysis, modeling, search, and prediction of protein structures. This paper investigated the effective combination of distance measures, which can exploit large protein structure database, in order to construct a protein fragment library representing native protein structures accurately. Clustering method was used to construct a protein fragment library. Initial clustering stage used inter alpha-carbon distance having low time complexity, and cluster extension stage used the combination of inter alpha-carbon distance, Binet-Cauchy distance, and root mean square deviation. Protein fragment library was constructed by leveraging large protein structure database using the proposed combination of distance measures. This library gives low root mean square deviation in the experiments representing protein structures with protein fragments.

• Journal of the Korea Society of Computer and Information
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• v.14 no.2
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• pp.69-77
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• 2009

Stream service environment demands real-time query processing for voluminous data which are ceaselessly delivered from tremendous sources. Typical R-tree based query processing technologies cannot efficiently handle such situations, which require repetitive and inefficient exploration from the tree root on every data event. However, many stream data including sensor readings show high locality, which we exploit to reduce the search space of queries to explore. In this paper, we propose a query processing scheme exploiting the locality of stream data. From the simulation, we conclude that the proposed scheme performs much better than the traditional ones in terms of scalability and exploration efficiency.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.1
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• pp.121-132
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• 2009

Default password protection used in operating systems have had many advances, but when the attacker has physical access to the server or gets root(administrator) privileges, the attacker can steal the password information(e.g. shadow file in Unix-like systems or SAM file in Windows), and using brute force and dictionary attacks can manage to obtain users' passwords. It is really difficult to obligate users to use complex passwords, so it is really common to find weak accounts to exploit. In this paper, we present a secure authentication scheme based on digital signatures and secure key storage that solves this problem, and explain the possible implementations using Trusted Platform Module(TPM). We also make a performance analysis of hardware and software TPMs inside implementations.

• The Journal of Industrial Distribution & Business
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• v.10 no.2
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• pp.65-75
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• 2019

Purpose - Along with Chinese exchange rate's reform advancement, the issue of exchange rate of RMB has increasingly become the heated focus in the world. In July 2005, China carried out the reform of the exchange rate system, and this behavior has aroused the attention of the world. However, the dispute on whether the theory of purchasing power parity holds or not in China still exists. As such, this paper will attempt to explore whether the purchasing power parity is significant in China. Research design, data, and methodology - The monthly data from July 2005 to December 2017 will be employed to analyze the nominal exchange rate of RMB against the US dollar and the nominal exchange rate of RMB against the euro. Based on these datum, an empirical analysis will be conducted under the unit root test and the cointegration test to exploit the significance of purchasing power parity in China. Results - The findings of this paper reveal that an increase in China's consumer price index will lead to an increase in the RMB exchange rate, which will lead to the depreciation of RMB. Concomitantly, an increase in the consumer price index in the US and Europe will result in a decrease in the RMB exchange rate, which will lead to an appreciation of RMB. In general, in terms of the US, if US consumer price index increases by 1%, China's nominal exchange rate against US dollar will decrease by 0.905%; if China's consumer price index increases by 1%, China's nominal exchange rate against US dollar will increase by 0.648%. In terms of Europe, if Europe consumer price index increases by 1%, China's nominal exchange rate against euro will decrease by 0.277%; If China's consumer price index increases by 1%, China's nominal exchange rate against euro will increase by 0.235%. Conclusions - Generally speaking, the empirical evidences this paper provided show that the purchasing power parity theory has a certain explanatory ability for the decision of RMB exchange rate. As such, the purchasing power parity cannot hold completely, and China's government should continue to deepen the reform of the exchange rate system to improve China's exchange rate market.

• Journal of Microbiology and Biotechnology
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• v.19 no.10
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• pp.1213-1222
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• 2009

The search for diverse plant growth-promoting (PGP) diazotrophic bacteria is gaining momentum as efforts are made to exploit them as biofertilizers for various economically important crops. In the present study, 17 diazotrophic strains belonging to eight different genera isolated from rice paddy fields were screened for multiple PGP traits and evaluated for their inoculation effects on canola and rice plants. All of the strains tested positive for 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity and production of indole 3-acetic acid (IAA) and ammonia ($NH_3$). Additionally, four of the strains were able to solubilize phosphorus (P), five tested positive for zinc (Zn) solubilization and sulfur (S) oxidation, and eight strains produced siderophores. Based on the presence of multiple PGP traits, 10 strains were selected for inoculation studies. Treatment with Herbaspirillum sp. RFNB26 resulted in maximum root length (54.3%), seedling vigor, and dry biomass in canola, whereas Paenibacillus sp. RFNB4 exhibited the lowest activity under gnotobiotic conditions. However, under pot culture conditions, Paenibacillus sp. RFNB4 significantly increased plant height and dry biomass production by 42.3% and 29.5%, respectively. Canola plants and rhizosphere soils inoculated with Bacillus sp. RFNB6 exhibited significantly higher nitrogenase activity. In greenhouse experiments, Serratia sp. RFNB18 increased rice plant height by 35.1%, Xanthomonas sp. RFNB24 enhanced biomass production by 84.6%, and rice rhizosphere soils inoculated with Herbaspirillum sp. RFNB26 exhibited the highest nitrogenase activity. Our findings indicate that most of the selected strains possess multiple PGP properties that significantly improve the growth parameters of the two plants when tested under controlled conditions.

• Journal of Korea Water Resources Association
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• v.51 no.11
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• pp.1021-1029
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• 2018

A primary objective of this study is to develop a drought forecasting technique based on groundwater which can be exploit for water supply under drought stress. For this purpose, we explored the lagged relationships between regionalized SGI (standardized groundwater level index) and SPI (standardized precipitation index) in view of the drought propagation. A regional prediction model was constructed using a NARX (nonlinear autoregressive exogenous) artificial neural network model which can effectively capture nonlinear relationships with the lagged independent variable. During the training phase, model performance in terms of correlation coefficient was found to be satisfactory with the correlation coefficient over 0.7. Moreover, the model performance was described by root mean squared error (RMSE). It can be concluded that the proposed approach is able to provide a reliable SGI forecasts along with rainfall forecasts provided by the Korea Meteorological Administration.

• Journal of KIISE:Information Networking
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• v.29 no.3
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• pp.253-264
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• 2002

Recently, hierarchical architectures of databases for location management have been proposed in order to accommodate the increase in user population in future personal communication systems. In particular, a 3-level hierarchical database architecture is compatible with current cellular mobile systems. In the architecture, a newly developed additional databases, regional location database(RLR), are positioned between HLR and VLRs. We propose an efficient cache scheme, called the Double T-thresholds Location Cache Scheme. The cache scheme extends the existing T-threshold location cache scheme which is competent only under 2-level architecture of location databases currently adopted by IS-41 and GSM. The idea behind our scheme is to use two pieces of cache information, VLR and RLR serving called portables. The two pieces are required in order to exploit root only locality of registration area(RA) but also locality of regional registration area(RRA) which is the wide area covered by RLR. We also use two threshold values in order to determine whether the two pieces are obsolete. In order to model the RRA residence time, the branching Eralng-$\infty$ distribution is introduced. Our minute cost analysis shows that the double T-threshold location cache scheme yields significant reduction of network and database costs for molt patterns of portables.

• Journal of Applied Biological Chemistry
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• v.55 no.2
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• pp.129-133
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• 2012

To exploit plant growth promoting bacteria in the roots of Miscanthus sacchariflorus, a biomass energy crop, total 64 bacteria were isolated. For the investigation of plant growth promoting effects from the isolated bacteria, production of indole acetic acid (IAA) and 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activities were tested and other cultural conditions were examined. As results, 8 isolates showed plant growth promoting effects on the M. sacchariflorus and an isolate designated Agrobacterium sp. BE516 has the highest activity by enhancing the shoot elongation over 2-fold than the control. Agrobacterium sp. BE516 produced 64 ${\mu}g$ IAA per mL and showed ACC deaminase activity which is involved in the resistance to environmental stress such as high salt and drought. It could grow at low temperature in the range from 4 to $15^{\circ}C$, at pH 4.0 and at 4% NaCl. These results indicate that the Agrobacterium sp. BE516 can be useful as a bio-fertilizer for M. sacchariflorus under the stressed conditions.