• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2303-2309
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• 2007

Expressed protein ligation (EPL) technique, joining recombinantly expressed proteins to polypeptides, has been widely adopted for addressing various biological questions and for drug discovery. However, joining two recombinant proteins together is sometimes difficult when proteins are expressed insoluble and unrefoldable, because ligation-active proteins via intein-fusion are obtainable when they are folded correctly. We overcame this limitation coexpressing target protein with additional methionine aminopeptidase (MAP) which enhances removal of the initiation methionine of recombinantly expressed protein. Our approach demonstrated that two domains of 46 kDa 5-Enolpyruvylshikimate-3-phosphate (EPSP) synthase, a target of herbicide glyphosate, were successfully joined by native chemical ligation, although its C-terminal domain was expressed as an inclusion body. The intein-fused N-terminal fragment of EPSP synthase (EPSPSN, residues 1-237) was expressed and the ligation-active thioester tagged N-terminal fragment (EPSPSN-thioester) was purified using a chitin affinity chromatography and mercapto-ethanesulphonate (MESNA) as intein thiolysis reagent. Its Cterminal fragment (EPSPSC, residues Met237-238CYS-427), expressed as an inclusion body, was prepared from an additional MAP-expressing strain. Protein ligation was initiated by mixing ~1 mM of EPSPSN-thioester with ~2 mM of EPSPSCCYS (residues 238CYS-427). Also we found that addition of 2% thiophenol increased the ligation efficiency via thiol exchange. The ligation efficiency was ~85%. The ligated full-length EPSP synthase was dissolved in 6 M GdHCl and refolded. Circular dichroism (CD) and enzyme activity assay of the purified protein showed that the ligated enzyme has distinct secondary structure and ~115% specific activity compared to those of wild-type EPSP synthase. This work demonstrates rare example of EPL between two recombinantly expressed proteins and also provides hands-on protein engineering protocol for large proteins.

• Journal of KIISE:Information Networking
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• v.31 no.2
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• pp.131-145
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• 2004

Mobile IP has been designed only to maintain communications as mobile devices move from a place to a place, so it does not guarantee Quality of Service (QoS). Hierarchical MIPv6 improved QoS somewhat using Mobility Anchor Point(MAP), but QoS guarantee problem still remains. QoS in mobile IP is important to provide multimedia and real-timeapplications services in a mobile environment, and QoS is closely related to handoff delay. Therefore, handoff delay problem is actively studied as a main issue in mobile IP research area to guarantee QoS. In this paper, we suggest SNMP Information-based routing that adds keyword management method to Information-based routing in an active network in order to resolve such a problem, Suggested QoS controlled method and existing handoff method, simulations are carried out with NS-2 for performance evaluation. The results of simulations show an improvement on handoff delay, and consequently the QoS improvement.

• Journal of Ginseng Research
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• v.48 no.1
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• pp.103-111
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• 2024

Background: Ginseng (Panax ginseng Mayer) is an important natural medicine. However, a long culture period and challenging quality control requirements limit its further use. Although artificial cultivation can yield a sustainable medicinal supply, research on the association between the transplantation and chaining of metabolic networks, especially the regulation of ginsenoside biosynthetic pathways, is limited. Methods: Herein, we performed Liquid chromatography tandem mass spectrometry based metabolomic measurements to evaluate ginsenoside accumulation and categorise differentially abundant metabolites (DAMs). Transcriptome measurements using an Illumina Platform were then conducted to probe the landscape of genetic alterations in ginseng at various ages in transplantation mode. Using pathway data and crosstalk DAMs obtained by MapMan, we constructed a metabolic profile of transplantation Ginseng. Results: Accumulation of active ingredients was not obvious during the first 4 years (in the field), but following transplantation, the ginsenoside content increased significantly from 6-8 years (in the wild). Glycerolipid metabolism and Glycerophospholipid metabolism were the most significant metabolic pathways, as Lipids and lipid-like molecule affected the yield of ginsenosides. Starch and sucrose were the most active metabolic pathways during transplantation Ginseng growth. Conclusion: This study expands our understanding of metabolic network features and the accumulation of specific compounds during different growth stages of this perennial herbaceous plant when growing in transplantation mode. The findings provide a basis for selecting the optimal transplanting time.

• Journal of Korea Multimedia Society
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• v.9 no.5
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• pp.649-657
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• 2006

Reinforcement Learning is a computational approach to learning whereby an agent take an action which maximize the total amount of reward it receives among possible actions within current state when interacting with a uncertain environment. Q-learning, one of the most active algorithm in Reinforcement Learning, is consist of rewards which is obtained when an agent take an action. But it has the problem with mapping real world to discrete states. When state spaces are very large, Q-learning suffers from time for learning. In constant, when the state space is reduced, many state spaces map to single state space. Because an agent only learns single action within many states, an agent takes an action monotonously. In this paper, to reduce time for learning and complement simple action, we propose the Q-learning using influence map(QIM). By using influence map and adjacent state space's learning result, an agent could choose proper action within uncertain state where an agent does not learn. When this paper compares simulation results of QIM and Q-learning, we show that QIM effects as same as Q-learning even thought QIM uses 4.6% of the Q-learning's state spaces. This is because QIM learns faster than Q-learning about 2.77 times and the state spaces which is needed to learn is reduced, so the occurred problem is complemented by the influence map.

• Journal of Korea Game Society
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• v.9 no.4
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• pp.3-10
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• 2009

Recently, various ways are being explored for enhancing the fun of computer games and lengthening the life cycle of them. This paper proposes the more active game environment by reflecting the decision that is made by collecting and analyzing user's behavioral data. The game results and traveling information of user is using for dynamic map creation. For experiment of the proposed method, we created games using the XNA Framework and confirmed the game environment which changing properly according to the user's game play.

• Proceedings of the KSRS Conference
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• v.1
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• pp.181-183
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• 2006

Digital topographic map in Korea contains layers of spatial and attribute data for 8 land features such as railroads, watercourses, roads, buildings and etc. Some of the layers such as building and forest don't include any information about height, which can be just prepared by interpretation of remote sensed data or field survey. LiDAR(Light Detection And Ranging) data using active pulse and digital camera provides data about height and form of land features. LiDAR data can be used not only to extract the outline of land features but also to estimate the height. This study presents technical availability for extraction and estimation of land feature's outline and height using LiDAR data which composes of natural and artificial land features, and digital aerial photograph which was taken simultaneously with the LiDAR. The estimated location, outline and height of land features were compared with the field survey data, and we could find that LiDAR data and digital aerial photograph can be a useful source for estimating the height of land features as well as extracting the outline.

• Journal of Power Electronics
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• v.16 no.2
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• pp.610-620
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• 2016

The compound active clamp zero voltage soft switching (CACZVS) three-phase power factor correction (PFC) converter has many advantages, such as high efficiency, high power factor, bi-directional energy flow, and soft switching of all the switches. Triple closed-loop PI controllers are used for the three-phase power factor correction converter. The control objectives of the converter include a fast transient response, high accuracy, and unity power factor. There are six parameters of the controllers that need to be tuned in order to obtain multi-objective optimization. However, six of the parameters are mutually dependent for the objectives. This is beyond the scope of the traditional experience based PI parameters tuning method. In this paper, an improved chaotic particle swarm optimization (CPSO) method has been proposed to optimize the controller parameters. In the proposed method, multi-dimensional chaotic sequences generated by spatiotemporal chaos map are used as initial particles to get a better initial distribution and to avoid local minimums. Pareto optimal solutions are also used to avoid the weight selection difficulty of the multi-objectives. Simulation and experiment results show the effectiveness and superiority of the proposed method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.4
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• pp.1010-1019
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• 2013

Recently, research on hologram, which can realize perfect 3-dimensional imaging, becomes more active. But hologram has the defect that it costs a lot in generation. Thus, this paper proposes a method to generate a new digital hologram contents by manipulating the existing digital hologram contents. That is, this paper proposes the method to manipulating the digital hologram contents by manipulating and/or synthesizing the depth information to get a new digital hologram contents. The proposed methods have been experimented with various depth informations and digital hologram contents. For each kind of depth information, it has been manipulated for its position and distance. The result was converted to a digital hologram by the computer-generated hologram method and the resulting hologram was reconstructed.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.17 no.4
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• pp.339-348
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• 1999

The information & Communication industry including internet is rapidly developing and expanding, which integrates our living space and provides diversity. Internet provides users with an variety of real-time information through networking. Also the functions and services of Geographic Information Systems are on a changing trend providing services for various organizations and users dispersed in different networks. It is necessary to understand that GIS is available not only on a desktop and server, but in any place where the network is connected using the web. Recently, Internet GIS for the search and subscription of spatial informations through the internet is receiving an active research field. So. this study aims to apply the Gas Disaster Management to the internet and develop the internet GIS techniques which make an effective utilization of GIS functions using MapObjects IMS, SDE, and Oracle.

• Journal of Integrative Natural Science
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• v.10 no.3
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• pp.141-147
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• 2017

Vascular endothelial growth factor (VEGF) is an important signaling protein involved in angiogenesis, which is the formation of new blood vessels from pre-existing vessels. Consequently, blocking of the vascular endothelial growth factor receptor (VEGFR-2) by small molecule inhibitors leads to the inhibition of cancer induced angiogenesis. In this study, we performed a two dimensional quantitative structure activity relationship (2D-QSAR) study of 38 N-Phenyl-N'-{4-(4-quinolyloxy) phenyl} urea derivatives as VEGFR-2 inhibitors based on hologram quantitative structure-activity (HQSAR). The model developed showed reasonable $q^2=0.521$ and $r^2=0.932$ values indicating good predictive ability and reliability. The atomic contribution map analysis of most active compound (compound 7) indicates that hydrogen and oxygen atoms in the side chain of ring A and oxygen atom in side chain of ring C contributes positively to the activity of the compounds. The HQSAR model developed and the atomic contribution map can serve as a guideline in designing new compounds for VEGFR-2 inhibition.