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Topic Modeling Based Warning Prioritization from Change Sets of Software Repository

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Journal of Computer Science & Technology 2020年第6期35卷 1461-1479页

作者： jung-Been Lee taek Lee Hoh Peter In College of Informatics Korea UniversitySeoul 02841Korea College of Knowledge-Based Services Engineering Sungshin UniversitySeoul 02844Korea

Many existing warning prioritization techniques seek to reorder the static analysis warnings such that true positives are provided first. However, excessive amount of time is required therein to investigate and fix prioritized warnings because some are not actually true positives or are irrelevant to the code context and topic. In this paper, we propose a warning prioritization technique that reflects various latent topics from bug-related code blocks. Our main aim is to build a prioritization model that comprises separate warning priorities depending on the topic of the change sets to identify the number of true positive warnings. For the performance evaluation of the proposed model, we employ a performance metric called warning detection rate, widely used in many warning prioritization studies, and compare the proposed model with other competitive techniques. Additionally, the effectiveness of our model is verified via the application of our technique to eight industrial projects of a real global company.

关键词： automated static analysis topic modeling warning prioritization

Fe_(3)GeTe_(2):a site-differentiated Hund metal

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npj Computational Materials 2022年第1期8卷 2355-2360页

作者： taek jung Kim Siheon Ryee Myung Joon Han Department of Physics KAISTDaejeon34141Republic of Korea I.Institute of Theoretical Physics University of HamburgNotkestrasse 9-11Hamburg22607Germany

Magnetism in two-dimensional(2D)van der Waals(vdW)materials has lately attracted considerable attention from the point of view of both fundamental science and device ***,establishing a detailed and solid understanding of their magnetism is the key first step toward various *** Fe_(3)GeTe_(2)is a representative ferromagnetic(FM)metal in this family,many aspects of its magnetic and electronic behaviors still remain ***,we report our new finding that Fe_(3)GeTe_(2)is a special type of correlated metal known as“Hund metal”.Furthermore,we demonstrate that Hund metallicity in this material is quite unique by exhibiting remarkable site dependence of Hund correlation strength,hereby dubbed“site-differentiated Hund metal”.Within this new picture,many of the previous experiments can be clearly understood,including the ones that were seemingly contradictory to one another.

关键词： strength establishing metallic

Programmable Logic Controller Block Monitoring System for Memory Attack Defense in Industrial Control Systems

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Computers, Materials & Continua 2023年第11期77卷 2427-2442页

作者： Mingyu Lee Jiho Shin jung taek Seo Department of Information Security Gachon UniversitySeongnam13120Korea Police Science Institute Korean National Police UniversityAsan31539Korea Department of Computer Engineering Gachon UniversitySeongnam13120Korea

Cyberattacks targeting industrial control systems(ICS)are becoming more sophisticated and advanced than in the past.A programmable logic controller(PLC),a core component of ICS,controls and monitors sensors and actuators in the ***,PLC has memory attack threats such as program injection and manipulation,which has long been a major target for attackers,and it is important to detect these attacks for ICS *** detect PLC memory attacks,a security system is required to acquire and monitor PLC memory *** addition,the performance impact of the security system on the PLC makes it difficult to apply to the *** address these challenges,this paper proposes a system to detect PLC memory attacks by continuously acquiring and monitoring PLC *** proposed system detects PLC memory attacks by acquiring the program blocks and block information directly from the same layer as the PLC and then comparing them in bytes with previous *** with Siemens S7-300 and S7-400 PLC were conducted to evaluate the PLC memory detection performance and performance impact on *** experimental results demonstrate that the proposed system detects all malicious organization block(OB)injection and data block(DB)manipulation,and the increment of PLC cycle time,the impact on PLC performance,was less than 1 *** proposed system detects PLC memory attacks with a simpler detection method than earlier ***,the proposed system can be applied to ICS with a small performance impact on PLC.

关键词： Programmable logic controller industrial control system attack detection

Solar Power Plant Network Packet-Based Anomaly Detection System for Cybersecurity

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Computers, Materials & Continua 2023年第10期77卷 757-779页

作者： Ju Hyeon Lee Jiho Shin jung taek Seo Department of Information Security Gachon UniversitySeongnam13120Korea Police Science Institute Korean National Police UniversityAsan31539Korea Department of Computer Engineering Gachon UniversitySeongnam13120Korea

As energy-related problems continue to emerge,the need for stable energy supplies and issues regarding both environmental and safety require urgent *** energy is becoming increasingly important,with solar power accounting for the most significant proportion of *** the scale and importance of solar energy have increased,cyber threats against solar power plants have also ***,we need an anomaly detection system that effectively detects cyber threats to solar power ***,as mentioned earlier,the existing solar power plant anomaly detection system monitors only operating information such as power generation,making it difficult to detect *** address this issue,in this paper,we propose a network packet-based anomaly detection system for the Programmable Logic Controller(PLC)of the inverter,an essential system of photovoltaic plants,to detect cyber *** and vulnerabilities in solar power plants were analyzed to identify cyber threats in solar power *** analysis shows that Denial of Service(DoS)and Manin-the-Middle(MitM)attacks are primarily carried out on inverters,aiming to disrupt solar plant *** develop an anomaly detection system,we performed preprocessing,such as correlation analysis and normalization for PLC network packets data and trained various machine learning-based classification models on such *** Random Forest model showed the best performance with an accuracy of 97.36%.The proposed system can detect anomalies based on network packets,identify potential cyber threats that cannot be identified by the anomaly detection system currently in use in solar power plants,and enhance the security of solar plants.

关键词： Renewable energy solar power plant cyber threat cybersecurity anomaly detection machine learning network packet

Prediction of high thermoelectric performance in the lowdimensional metal halide Cs_(3)Cu_(2)I_(5)

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npj Computational Materials 2021年第1期7卷 476-481页

作者： Young-Kwang jung In taek Han Yong Churl Kim Aron Walsh Department of Materials Science and Engineering Yonsei UniversitySeoulSouth Korea Samsung Advanced Institute of Technology(SAIT) Samsung Electronics Materials Research ComplexYoungtongSuwonSouth Korea Department of Materials Imperial College LondonLondonUK

Metal halides have emerged as a new generation of semiconductors with applications ranging from solar cells to chemical *** assess the thermoelectric potential of Cs_(3)Cu_(2)I_(5),which has a crystal structure formed of zero-dimensional[Cu_(2)I_(5)]3−anionic clusters that are separated by Cs+counter *** find the compound exhibits the characteristics of a phonon-glass electroncrystal with a large imbalance in the conduction of heat and electrons predicted from first-principles transport *** anharmonic phonon–phonon scattering results in short-lived acoustic vibrations and an ultra-low lattice thermal conductivity(10 cm^(2)V^(−1)s^(−1)).For an n-type crystal at 600 K,a thermoelectric figure-of-merit ZT of 2.6 is found to be accessible,which for a cold source of 300 K corresponds to a thermodynamic heat-to-electricity conversion efficiency of 15%.

关键词： theory phonon crystal

A Comparison of GPS- and NWP-derived PW Data over the Korean Peninsula

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Advances in Atmospheric Sciences 2010年第4期27卷 871-882页

作者： Ha-taek KWON Eui-Hyun jung Gyu-Ho LIM School of Earth and Environmental Sciences Seoul National University Seoul 151-172 Korea

Precipitable Water （PW） derived from Global Positioning System （GPS） measurements and numerical weather prediction （NWP） model analysis data were compared to further evaluate the effcacy of applying GPS-derived PW to the NWP model. The spatial and temporal variations of GPS-derived PW during a rainfall event were also examined. GPS-derived PW measurements show good agreement with the behavior of water vapor at a high spatial resolution during the analysis period. Temporal anomalies of GPS-derived PW moving along with the front are successfully detected by the GPS array. Large positive anomalies of GPS-derived PW are indicated immediately before a rainfall event, and the intensity of these positive anomalies do not seem to decrease significantly as the precipitation system passes. These results indicate that the Korean GPS network may have great potential as a PW sensor over the Korean Peninsula. In contrast with GPS-derived PW, NWP-derived PW shows negative biases. These biases appear to stem mainly from the differences between modeled and actual GPS site elevations, as GPS sites were generally located at elevations lower than those employed by the NWP model. However, there still exists a discernable dry bias after a PW correction is applied to NWP-derived PW. GPS-derived PW better reflects the spatial and temporal moisture variations of precipitation systems, as compared to NWP-derived PW. These results provide entirely new information for improving the regional NWP system, since GPS-derived PW produced with data from the Korean GPS network may be incorporated into the NWP model to improve rainfall forecasts.

关键词： GPS precipitable water numerical weather prediction model dry bias

Improving Method of Anomaly Detection Performance for Industrial IoT Environment

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Computers, Materials & Continua 2022年第9期72卷 5377-5394页

作者： Junwon Kim Jiho Shin Ki-Woong Park jung taek Seo Department of Information Security Engineering Gachon UniversitySeongnam13120Korea Police Science Institute Korea National Police UniversityAsan31539Korea SysCore Lab. Sejong UniversitySeoul05006Korea Department of Computer Engineering Gachon UniversitySeongnam13120Korea

Industrial Control System(ICS),which is based on Industrial IoT(IIoT),has an intelligent mobile environment that supports various mobility,but there is a limit to relying only on the physical security of the ICS *** to various threat factors that can disrupt the workflow of the IIoT,machine learning-based anomaly detection technologies are being presented;it is also essential to study for increasing detection performance to minimize model errors for promoting stable ICS *** this paper,we established the requirements for improving the anomaly detection performance in the IIoT-based ICS environment by analyzing the related *** that,we presented an improving method of the performance of a machine learning model specialized for IIoT-based ICS,which increases the detection rate by applying correlation coefficients and clustering;it provides a mechanism to predict thresholds on a ***,we adopted the HAI dataset environment that actively reflected the characteristics of IIoT-based ICS and demonstrated that performance could be improved through comparative experiments with the traditional method and our proposed *** presented method can further improve the performance of commonly applied error-based detection techniques and includes a primary method that can be enhanced over existing detection techniques by analyzing correlation coefficients between features to consider feedback between ICS *** can contribute to improving the performance of several detection models applied in ICS and other areas.

关键词： Industrial IoT industrial control system anomaly detection clustering algorithm correlation coefficient

Evaluation of particle growth systems for sampling and analysis of atmospheric fine particles

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Particuology 2011年第6期9卷 606-610页

作者： Dae Seong Kim Sang Bum Hong jung-taek Kwon Kihong Park Department of Environmental Science and Engineering Gwangju Institute of Science and Technology Korea Polar Research Institute Laboratory of Toxicology College of Veterinary Medicine Seoul National University

Three types of water-based condensational growth systems, which can enable particles to grow in size to facilitate sampling and subsequent chemical analysis, were evaluated. The first one is a mixing type growth system where aerosols are mixed with saturated water vapor, the second one is a thermal diffusive growth system where warm flow enters cold-walled tube, and the third one is a laminar flow type where cold flow enters a warm wet-wall tube. Hygroscopic sodium chloride （NaCl）, ammonium sulfate （（NH4）2SO4） and ammonium nitrate （NH4N03）, and non-hygroscopic polystyrene latex （PSL） particles, in the size range of 50-400 nm, were used to determine their growth factors through the growth systems. Our data showed that the third-type growth system could enable particles to grow most efficiently regardless of their hygroscopic property. Collection efficiency of particles in the size range of 0.05-2.5 μm, in a continuous aerosol sampler after they passed through the third-type growth system was about 100%, suggesting that the third-type growth system would he the most useful among the tested growth systems for sampling and subsequent chemical analysis of fine and ultrafine particles.

关键词： Particle growth chamber Condensational growth Particle sampler Hygroscopic particles

A Novel Transparent and Auditable Fog-Assisted Cloud Storage with Compensation Mechanism

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Tsinghua Science and Technology 2020年第1期25卷 28-43页

作者： Donghyun Kim junggab Son Daehee Seo Yeojin Kim Hyobin Kim jung taek Seo Department of Computer Science Kennesaw State UniversityMariettaGA 30060USA Department of Information Security Engineering Soonchunhyang UniversityAsan 31538South Korea

This paper introduces a new fog-assisted cloud storage which can achieve much higher throughput compared to the traditional cloud-only storage architecture by reducing the traffics toward the cloud storage. The fog-storage service providers are transparency to end-users and therefore, no modification on the end-user devices is necessary. This new system is featured with(1) a stronger audit scheme which is naturally coupled with the proposed architecture and does not suffer from the replay attack and(2) a transparent and efficient compensation mechanism for the fog-storage service providers. We provide rigorous theoretical analysis on the correctness and soundness of the proposed system. To the best of our knowledge, this is the first paper to discuss about a storage data audit scheme for fog-assisted cloud storage as well as the compensation mechanism for the service providers of the fog-storage service providers.

关键词： fog computing cloud computing network storage data audit merkle hash tree integer factorization payment transparency