• Journal of Institute of Control, Robotics and Systems
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• v.19 no.4
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• pp.328-333
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• 2013

Since a slight malfunction of control systems in a nuclear power plant may cause huge catastrophes, such control systems usually have multiple redundancy and reliable features, and their reliability and availability should be analyzed and verified thoroughly. This paper performed the reliability analysis of the SPLC (Safety Programmable Logic Controller) that is under developed as the control systems for the next generation nuclear power plant. One of the key features of SPLC is that it has multiple redundancy modes as faults happen, which means the reliability analysis for one fixed redundant model is not enough to analyze the reliability of SPLC. With considering this reconfigurable concept, FTA (Fault Tree Analysis) was used to capture fault-relationship among sub-modules. The analysis results show that MTTF (Mean Time to Fault) of SPLC is 45,080 hours, which is a about 4.5 times longer than the regulation, 10,000 hours.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.3
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• pp.358-363
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• 2014

In this paper, we present two constructions of the attribute-based broadcast encryption(ABBE) algorithm. Attribute-based encryption(ABE) algorithm enables an access control mechanism over encrypted data by specifying access policies among private keys and ciphertexts. ABBE algorithm can be used to construct ABE algorithm with revocation mechanism. Revocation has a useful property that revocation can be done without affecting any non-revoked uers. The main difference between our algorithm and the classical ones derived from the complete subtree paradigm which is apt for military hierarchy. Our algorithm improve the efficiency from the previously best ABBE algorithm, in particular, our algorithm allows one to select or revoke users by sending ciphertext of constant size with respect to the number of attributes and by storing logarithm secret key size of the number of users. Therefore, our algorithm can be an option to applications where computation cost is a top priority and can be applied to military technologies in the near future.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.1
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• pp.47-52
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• 2017

This study is BIT(: Bus Information Terminal) features that take advantage of KEPCO eIoT(: energy Internet of Thing) platform, and it's Network configuration is composed of display terminal device, gateway, platform, and the service server. The key features are parts for processing protocol data between the gateway and the device using LoRa(: Long Range) technology, Intelligent applications and SIP(: Session Initiation Protocol) data handling connected to the Taxi reservation system. And the resource tree provided BIT for the service, which commonly used in the application server and the device.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.11
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• pp.1107-1112
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• 2016

This study is the Smart Office features that take advantage of KEPCO eIoT(: energy Internet of Thing) platform, and it's Network configuration is composed of sensing device, gateway, platform, and the service server. The key features are parts for processing protocol data between the gateway and the device using LoRa(: Long Range) technology, Intelligent applications and public safety data connected to the PS-LTE(: Public Safety-Long-Term Evolution) system. And the resource tree provided Smart Office for the service, which commonly used in the application server and the device.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5A
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• pp.709-716
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• 2000

We present an efficient algorithm using region-based average of variations of local correlation coefficients (LCC) for the extraction of texture regions. The key idea of this algorithm for the classification of texture and shade regions is to utilize the fact that the averages of the variations of LCCs according to different orientations texture regions are clearly larger than those in shade regions. In order to evaluate the performance of the proposed algorithm, we use nine test images (Lena, Bsail, Camera Man, Face, Woman, Elaine, Jet, Tree, and Tank) of 8-bit 256$\times$256 pixels. Experimental results show that the proposed feature extracts well the regions which appear visually as texture regions.

• Journal of the Korean Wood Science and Technology
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• v.44 no.4
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• pp.559-570
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• 2016

The EtOAc and $H_2O$ soluble fractions of Katsura tree (Cercidiphyllum japonicum Sieb. Et Zucc) bark extracts were chromatographed on a Sephadex LH-20 column with various aqueous MeOH. Gallic acid (1), methyl galate (2), kurigalin (3), 1,2,3,6-tetra-O-galloyl-${\beta}$-D-glucose (4) and 1,2,3,4,6-penta-O-galloyl-${\beta}$-D-glucose (5) were isolated from EtOAc fraction. Isocorilagin (6) and methyl galate (2) were separated from $H_2O$ fraction. The structure determination was done by $^1H$ and $^{13}C$ NMR. Of these isolated compounds, methyl galate (2), kurigalin (3) and isocorilagin (6) were isolated, for the first time, from the bark extracts of Cercidiphyllum japonicum.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.4
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• pp.1442-1462
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• 2014

Packet classification is a key technology of the Internet for routers to classify the arriving packets into different flows according to the predefined rulesets. Previous packet classification algorithms have mainly focused on search speed and memory usage, while overlooking update performance. In this paper, we propose PreCuts, which can drastically improve the update speed. According to the characteristics of IP field, we implement three heuristics to build a 3-layer decision tree. In the first layer, we group the rules with the same highest byte of source and destination IP addresses. For the second layer, we cluster the rules which share the same IP prefix length. Finally, we use the heuristic of information entropy-based bit partition to choose some specific bits of IP prefix to split the ruleset into subsets. The heuristics of PreCuts will not introduce rule duplication and incremental update will not reduce the time and space performance. Using ClassBench, it is shown that compared with BRPS and EffiCuts, the proposed algorithm not only improves the time and space performance, but also greatly increases the update speed.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.33.2-33.2
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• 2014

Halo merger trees are essential backbones of semi-analytic models for galaxy formation and evolution. Recent studies have pointed out that extracting merger trees from numerical simulations of structure formation is non-trivial; different algorithm can give differing merger histories. Thus they should be carefully understood before being used as input for models of galaxy formation. As one of the projects proposed in the SUSSING MERGER TREES Workshop, we investigate the impact of different halo merger trees on a semi-analytic model. We find that the z = 0 global galaxy properties in our model show differences between trees when using a common parameter set, but that these differences are not very significant. However, the star formation history of the Universe and the properties of satellite galaxies can show marked differences between trees with different methods for constructing a tree. Calibrating the SAM for each tree individually to the empirical data can reduce the discrepancies between the z = 0 global galaxy properties, however this is at cost of increasing the differences in evolutionary histories of galaxies. Furthermore, the underlying physics implied can vary, resulting in key quantities such as the supernova feedback efficiency differing by factors of 2. Such a change alters the regimes where star formation is primarily suppressed by supernovae. Therefore, halo merger trees extracted from a common halo catalogue using different, but reliable, algorithms can result in a difference in the semi-analytic model, however, given the enormous uncertainties in galaxy formation physics, these are not necessarily significant.

• IEMEK Journal of Embedded Systems and Applications
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• v.8 no.5
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• pp.285-293
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• 2013

The procedure of the arbitration which is the tag collision is essential because the multiple tags response simultaneously in the same frequency to the request of the Reader. This procedure is known as Anti-collision and it is a key technology in the RFID system. In this paper, we propose the Bit Pattern Prediction Algorithm(BPPA) for the efficient identification of the multiple tags. The BPPA is based on the tree algorithm using the time slot and identify the tag quickly and efficiently using accurate bit pattern prediction method. Through mathematical performance analysis, We proved that the BPPA is an O(n) algorithm by analyzing the worst-case time complexity and the BPPA's performance is improved compared to existing algorithms. Through MATLAB simulation experiments, we verified that the BPPA require the average 1.2 times query per one tag identification and the BPPA ensure stable performance regardless of the number of the tags.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.5A
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• pp.358-366
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• 2012

LED-ID (Light Emitting Diode - Identification) is one of the key technologies for identification, data transmission, and illumination simultaneously. This is the new paradigm in the identification technology environment. There are many issues are still now challenging to achieve high performance in LED-ID system. Collision issue is one of them. Actually this is the most significant issue in all identification system. LED-ID system also suffers from collision problem. In our system, collision occurs when two or more readers transmit data to tag at the same time or vice versa. There are many anti-collision protocols to resolve this problem; such as: Slotted ALOHA, Basic Frame Slotted ALOHA, Query Tree, Tree Splitting, and Q-Algorithm etc. In this paper, we propose modified Q-Algorithm to resolve collision at tag. The proposed protocol is based on Q-Algorithm and used the information of arrived readers to a tag from neighbor. The information includes transmitting slot number of readers and the number of readers that can be arrived in next slot. Our proposed protocol can reduce the numbers of collision slot and the successful time to identify all readers. In this paper our simulation and theoretical results are presented.