• KIPS Transactions on Computer and Communication Systems
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• v.2 no.8
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• pp.317-326
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• 2013

In this paper, we present an effective method for comparing control flow graphs which represent static structures of binary programs. To compare control flow graphs, we measure similarities by comparing instructions and syntactic information contained in basic blocks. In addition, we also consider similarities of edges, which represent control flows between basic blocks, by edge extension. Based on the comparison results of basic blocks and edges, we match most similar basic blocks in two control flow graphs, and then calculate the similarity between control flow graphs. We evaluate the proposed edge extension method in real world Java programs with respect to structural similarities of their control flow graphs. To compare the performance of the proposed method, we also performed experiments with a previous structural comparison for control flow graphs. From the experimental results, the proposed method is evaluated to have enough distinction ability between control flow graphs which have different structural characteristics. Although the method takes more time than previous method, it is evaluated to be more resilient than previous method in comparing control flow graphs which have similar structural characteristics. Control flow graph can be effectively used in program analysis and understanding, and the proposed method is expected to be applied to various areas, such as code optimization, detection of similar code, and detection of code plagiarism.

• Journal of Korean Society of Transportation
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• v.33 no.6
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• pp.564-574
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• 2015

As shown by the popularity of the rapid train in the Seoul Metro Line No. 9, the demand for the rapidization of the metro transit has been continuously increased. However, it needs tremendous cost to construct new additional infrastructures to the existing line for the rapidization. In order to overcome the problem, utilizing the existing infrastructures such as crossing tracks as railroad sidetracks can be considered to be a good method of reducing the cost. In this case, there is a way exploiting the existing train as an express train and the advanced train, which increases both acceleration and deceleration, as a local train, but achievable acceleration and deceleration have not been analyzed rigorously. In this paper, we analyze feasible ranges and optimal values of both acceleration and deceleration of the advanced train analytically when we consider the rapidization of the metro transit utilizing the existing infrastructures and verify the results in Seoul Metro Line No. 3. Simulation results show ranges and optimal values of achievable acceleration and deceleration exist when minimum gap between an express train and a local train is smaller than 40 seconds.

• Journal of KIISE
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• v.42 no.8
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• pp.1057-1064
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• 2015

The tactical network is system based on wireless networking technologies that ties together surveillance reconnaissance systems, precision strike systems and command and control systems. Several alternative paths exist in the network because it is connected as a grid to improve its survivability. In addition, the network topology changes frequently as forces and combatants change their network access points while conducting operations. However, most Internet routing standards have been designed for use in stable backbone networks. Therefore, tactical networks may exhibit a deterioration in performance when these standards are implemented. In this paper, we propose Priority based Multi-Path routing with Local Optimization(PMPLO) for a tactical backbone network. The PMPLO separately manages the global and local metrics. The global metric propagates to other routers through the use of a routing protocol, and it is used for a multi-path configuration that is guaranteed to be loop free. The local metric reflects the link utilization that is used to find an alternate path when congestion occurs, and it is managed internally only within each router. It also produces traffic that has a high priority privilege when choosing the optimal path. Finally, we conducted a simulation to verify that the PMPLO can effectively distribute the user traffic among available routers.

• The KIPS Transactions:PartD
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• v.10D no.2
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• pp.233-246
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• 2003

The mediator-based system integrates heterogeneous information systems with the flexible manner. But it does not give much attention on the query optimization issues, especially for the query reusing. The other thing is that it does not use standardized metadata for schema matching. To improve this two issues, we propose mediator-based Distributed Information Integration System (DIIS) which uses query caching regarding performance and uses ISO/IEC 11179 metadata registry in terms of standardization. The DIIS is designed to provide decision-making support, which logically integrates the distributed heterogeneous business information systems based on the Web environment. We designed the system in the aspect of three-layer expression formula architecture using the layered pattern to improve the system reusability and to facilitate the system maintenance. The functionality and flow of core components of three-layer architecture are expressed in terms of process line diagrams and assembly line diagrams of Eriksson Penker Extension Model (EPEM), a methodology of an extension of UML. For the implementation, Supply Chain Management (SCM) domain is used. And we used the Web-based environment for user interface. The DIIS supports functions of query caching and query reusability through Query Function Manager (QFM) and Query Function Repository (QFR) such that it enhances the query processing speed and query reusability by caching the frequently used queries and optimizing the query cost. The DIIS solves the diverse heterogeneity problems by mapping MetaData Registry (MDR) based on ISO/IEC 11179 and Schema Repository (SCR).

• Korean Chemical Engineering Research
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• v.43 no.5
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• pp.549-559
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• 2005

Sustainable industrial development which can minimize an ecological effect by the mankind exertion is recently interested due to an environmental contamination and a resource exhaustion problem. An eco-industrial park (EIP) is a community of manufacturing and service businesses seeking enhanced environmental and economic performance through collaboration in managing environmental and resource issues, including energy, water, and materials. EIP developments which improve a production plant within an eco-friendly greenfield and design a new industrial ecosystem are accomplished recently, which can efficiently re-use the waste and resources from each company within EIP. In this review, the outside and domestic case studies of EIP and cornerstone technologies to develop the EIP, such as energy integration, waste reuse, mass flow analysis, water pinch, and life cycle assessment, are summarized.

• Electronic Materials Letters
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• v.14 no.6
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• pp.689-699
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• 2018

Nanostructured Ni doped $Bi_2S_3$ ($Bi_{2-x}Ni_xS_3$, $0{\leq}x{\leq}0.07$) is explored as a candidate for telluride free thermoelectric material, through a combination process of mechanical alloying with subsequent consolidation by cold pressing followed with a sintering process. The cold pressing method was found to impact the thermoelectric properties in two ways: (1) introduction of the dopant atom in the interstitial sites of the crystal lattice which results in an increase in carrier concentration, and (2) introduction of a porous structure which reduces the thermal conductivity. The electrical resistivity of $Bi_2S_3$ was decreased by adding Ni atoms, which shows a minimum value of $2.35{\times}10^{-3}{\Omega}m$ at $300^{\circ}C$ for $Bi_{1.99}Ni_{0.01}S_3$ sample. The presence of porous structures gives a significant effect on reduction of thermal conductivity, by a reduction of ~ 59.6% compared to a high density $Bi_2S_3$. The thermal conductivity of $Bi_{2-x}Ni_xS_3$ ranges from 0.31 to 0.52 W/m K in the temperature range of $27^{\circ}C$ (RT) to $300^{\circ}C$ with the lowest ${\kappa}$ values of $Bi_2S_3$ compared to the previous works. A maximum ZT value of 0.13 at $300^{\circ}C$ was achieved for $Bi_{1.99}Ni_{0.01}S_3$ sample, which is about 2.6 times higher than (0.05) of $Bi_2S_3$ sample. This work show an optimization pathway to improve thermoelectric performance of $Bi_2S_3$ through Ni doping and introduction of porosity.

• Geophysics and Geophysical Exploration
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• v.15 no.3
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• pp.129-135
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• 2012

The simultaneous-source full waveform inversion improves the applicability of full waveform inversion by reducing the computational cost. Since this technique adopts simultaneous multi-source for forward modeling, unwanted events remain in the residual seismograms when the receiver geometry of field acquisition is different from that of numerical modeling. As a result, these events impede the convergence of the full waveform inversion. In particular, the streamer-type data with limited offsets is the most difficult data to apply the simultaneous-source technique. To overcome this problem, the global-correlation-based objective function was suggested and it was successfully applied to the simultaneous-source full waveform inversion in time domain. However, this method distorts residual wavefields due to the modified objective function and has a negative influence on the inversion result. In addition, this method has not been applied to the frequency-domain simultaneous-source full waveform inversion. In this paper, we apply a timedamping function to the observed and modeled data, which are used to compute global correlation, to minimize the distortion of residual wavefields. Since the damped wavefields optimize the performance of the global correlation, it mitigates the distortion of the residual wavefields and improves the inversion result. Our algorithm incorporates the globalcorrelation-based full waveform inversion into the frequency domain by back-propagating the time-domain residual wavefields in the frequency domain. Through the numerical examples using the streamer-type data, we show that our inversion algorithm better describes the velocity structure than the conventional global correlation approach does.

• Korean Journal of Remote Sensing
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• v.37 no.5_1
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• pp.1149-1161
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• 2021

With a trend of the utilization of computer vision for satellite images, cloud detection using deep learning also attracts attention recently. In this study, we conducted a U-Net cloud detection modeling using SPARCS (Spatial Procedures for Automated Removal of Cloud and Shadow) Cloud Dataset with the image data augmentation and carried out 10-fold cross-validation for an objective assessment of the model. Asthe result of the blind test for 1800 datasets with 512 by 512 pixels, relatively high performance with the accuracy of 0.821, the precision of 0.847, the recall of 0.821, the F1-score of 0.831, and the IoU (Intersection over Union) of 0.723. Although 14.5% of actual cloud shadows were misclassified as land, and 19.7% of actual clouds were misidentified as land, this can be overcome by increasing the quality and quantity of label datasets. Moreover, a state-of-the-art DeepLab V3+ model and the NAS (Neural Architecture Search) optimization technique can help the cloud detection for CAS500 (Compact Advanced Satellite 500) in South Korea.

• Convergence Security Journal
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• v.21 no.1
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• pp.191-200
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• 2021

Artificial intelligence technology is developing in an environment where a lot of data is produced due to the development of computing technology, a cloud environment that can store data, and the spread of personal mobile phones. Among these artificial intelligence technologies, the deep neural network provides excellent performance in image recognition and image classification. There have been many studies on image detection for forest fires and fire prevention using such a deep neural network, but studies on detection of cigarette smoking were insufficient. Meanwhile, military units are establishing surveillance systems for various facilities through CCTV, and it is necessary to detect smoking near ammunition stores or non-smoking areas to prevent fires and explosions. In this paper, by reflecting experimentally optimized numerical values such as activation function and learning rate, we did the detection of smoking pictures and non-smoking pictures in two cases. As experimental data, data was constructed by crawling using pictures of smoking and non-smoking published on the Internet, and a machine learning library was used. As a result of the experiment, when the learning rate is 0.004 and the optimization algorithm Adam is used, it can be seen that the accuracy of 93% and F1-score of 94% are obtained.

• Journal of Climate Change Research
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• v.2 no.3
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• pp.175-189
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• 2011

In this research, we describe the methodology and the quantification about GHG reduction effects, expected by optimization of operation mode according to establishing additional heat storage system of Bundang Combined Cycle Power Plant. As an intermediate form of General Combined Cycle Power Plant and Heat supply only district heating plant, Bundang Combined Cycle Power Plant(and Ilsan, Anyang, Bucheon) is possible to satisfy demand for the electrical load and thermal load capacity at the same time through changes to the operation mode itself. Therefore, through the operating transition of high-efficiency mode that the condenser cooling water is recovered and supplied to district heat and cooling, establishing additional heat storage system have flexible supply ability at the power and heat market. In this research, We calculated using the operating performance for the last three years(2008~2010) and efficiency of each mode-specific values. As a result, GHG reduction effects were calculated as $97.95kg_{-}CO_2/Gcal$ per heat energy 1 Gcal supplied at the heat storage system and we expected emmision reduction effect about $13,500Ton_{-}CO_2/yr$.