• Journal of the Korean Geotechnical Society
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• v.21 no.4
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• pp.5-12
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• 2005

Recently, geophysical prospecting methods have played very important roles in civil and environmental engineering problems. Technical advances in geophysical instruments and computer system made it possible to get underground images with very high resolution far purposes to resolve those problems. It was possible partly due to ever increasing demand for development of technologies needed to precisely detect polluted areas and prevent ground-related accidents. Based on the same demand, integrity tests of cast-in place piles draw more attention and development of accurate test procedures is required. Ultrasonic methods is one of most advanced non-destructive procedures. In the paper, a geotomography method is employed for the cast-in place pile integrity test using ultrasonic waves. The image of pile interior is scanned and scrutinized far better and more accurate decision in the cast-in place pile integrity. In this study, we firstly examined the accuracy fur tomography program with idealized synthetic models built in water tank: their position and size were changed in the tank and each case was studied. In the next stage, real concrete pile models were fabricated and images of anomaly areas inside the pile were scanned to successfully locate those areas.

• Journal of Environmental Science International
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• v.18 no.3
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• pp.315-323
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• 2009

Hydraulic gradient of the landfill soils is estimated by Devlin (2003) method, and its variation characteristics from rainfall and permeability of the aquifer material are analyzed. The study site of 18 m $\times$ 12 m is located in front of the Environment Research Center at the Pukyong National University, and core logging, slug/bail test and groundwater monitoring was performed. The sluglbail tests were performed in 9 wells (except BH9 well), and drawdown data with elapsed time for bail tests were analyzed using Bouwer-Rice and Hvorslev methods. The average hydraulic conductivity estimated in each of the test wells was ranged $1.991{\times}10^{-7}{\sim}4.714{\times}10^{-6}m/sec$, and the average hydraulic conductivity in the study site was estimated $2.376{\times}10^{-6}m/sec$ for arithmetic average, $1.655{\times}10^{-6}m/sec$ for geometric average and $9.366{\times}10^{-7}m/sec$ for harmonic average. The permeability of landfill soils was higher at the east side of the study site than at the west side. Groundwater level in 10 wells was monitored 44 times from October 2 to November 7, 2007. The groundwater level was ranged 1.187$\sim$1.610 m, and the average groundwater level range in each of the well showed 1.256$\sim$1.407 m. The groundwater level was higher at the east side than at the west side of the study site, and this distribution is identify to it of hydraulic conductivity. The hydraulie gradient and the major flow direction for 10 wells were estimated 0.0072$\sim$0.0093 and $81.7618{\sim}88.0836^{\circ}$, respectively. Also, the hydraulic gradient and the major flow direction for 9 wells were estimated 0.0102$\sim$0.0124 and $84.6822{\sim}89.1174^{\circ}$, respectively. The hydraulic gradient of the study site increased from rainfall (83.5 mm) on October 7, causing by that the groundwater level of the site with high permeability was higher. The hydraulic gradient estimated on and after October 16 was stable, due to almost no rainfall. Thus, it was confirmed that the variation of the hydraulic gradient in the landfill soils was controlled by the rainfall.

• Journal of KIISE:Software and Applications
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• v.33 no.9
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• pp.787-801
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• 2006

Ontology merging describes the process of integrating two ontologies into a new ontology. How this is done best is a subject of ongoing research in the Semantic Web, Data Integration, Knowledge Management System, and other ontology-related application systems. Earlier research on ontology merging, however, has studied for developing effective ontology matching approaches but missed analyzing and solving methods of problems of merging two ontologies given correspondences between them. In this paper, we propose a specific ontology merging process and a generic operator, T-MERGE, for integrating two source ontologies into a new ontology. Also, we define a taxonomy of merging conflicts which is derived from differing representations between input ontologies and a method for detecting and resolving them. Our T-MERGE operator encapsulates the process of detection and resolution of conflicts and merging two entities based on given correspondences between them. We define a data structure, MergeLog, for logging the execution of T-MERGE operator. MergeLog is used to inform detailed results of execution of merging to users or recover errors. For our experiments, we used oriental philosophy ontologies, western philosophy ontologies, Yahoo western philosophy dictionary, and Naver philosophy dictionary as input ontologies. Our experiments show that the automatic merging module compared with manual merging by a expert has advantages in terms of time and effort.

• The Journal of Engineering Geology
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• v.25 no.3
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• pp.349-356
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• 2015

Although geophysical methods are useful and generally provide valuable information about the subsurface, it is important to recognize their limitations. A common limitation is the lack of sufficient contrast in physical properties between different layers. Thus, multiple methods are commonly used to best constrain the physical properties of different layers and interpret each section individually. Ground penetrating radar (GPR) and shallow seismic reflection (SSR) methods, used for shallow and very shallow subsurface imaging, respond to dielectric and velocity contrasts between layers, respectively. In this study, we merged GPR and SSR data from a test site within the Cheongui granitic mass, where the water table is ~3 m deep all year. We interpreted the data in combination with field observations and existing data from drill cores and well logs. GPR and SSR reflections from the tops of the sand layer, water table, and weathered and soft rocks are successfully mapped in a single section, and they correlate well with electrical resistivity data and SPS (suspension PS) well-logging profiles. In addition, subsurface interfaces in the integrated section correlate well with S-wave velocity structures from multi-channel analysis shear wave (MASW) data, a method that was recently developed to enhance lateral resolution on the basis of CMP (common midpoint) cross-correlation (CMPCC) analysis.

• The Journal of Engineering Geology
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• v.11 no.3
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• pp.303-313
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• 2001

A cut-slope near Guam-Ri Hwado-Eup Namyangju-Si Kyunggi-Do collapsed during a heavy rainfall over 400mm at 28th of August 2000. The cut-slope collapse reportedly developed mainly by block sliding along a set of discontinuities, although slope angle of the cut-slope was 40$^{\circ}$(1:1.2) that agrees with the road construction criteria. This study aims to analyze differences and correlations among several data-collecting methods limited to discontinuity analysis related with cut-slope collapse. This study started with analysing discontinuity surface characteristics, geology of the country rock and orientations of the discontinuities directly related with the collapse. Analysis of aerial photos around the study area provided regional lineament data, and discontinuity plane description and measurements were collected from core logging and Borehole Image Processing System (BIPS). Spearmans correlation ranking coefficient method was used to get correlation of discontinuity planes according to analysis methods. The result suggests that the correlation coefficient is ${\gamma}_s$ = 0.91 Plus, stability analysis of discontinuity plane orientation data using equal-area stereonet revealed that the study area is unstable to planar failure. This study suggests that the cut-slope angles currently applied should be shallower and that significant attention is required to orientation distribution of discontinuities existed in cut-slopes studies.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.4
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• pp.95-102
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• 2016

Computer security incident such as confidential information leak and data destruction are constantly growing and it becomes threat to information in digital devices. To respond against the incident, digital forensic techniques are also developing to help digital incident investigation. With the development of digital forensic technology, a variety of forensic artifact has been developed to trace the behavior of users. Also, a diversity of forensic tool has been developed to extract information from forensic artifact. However, there is a issue that information from forensic tools has its own forms. To solve this problem, it needs to process data when it is output from forensic tools. Then it needs to compare and analyze processed data to identify how data is related each other and interpret the implications. To reach this, it calls for effective method to store and output data in the course of data processing. This paper aims to propose DFIOC (Digital Forensic Indicators Of Compromise) that is capable of transcribing a variety of forensic artifact information effectively during incident analysis and response. DFIOC, which is XML based format, provides "Evidence" to represent various forensic artifacts in the incident investigation. Furthermore, It provides "Forensic Analysis" to report forensic analysis result and also gives "Indicator" to investigate the trace of incidence quickly. By logging data into one sheet in DFIOC format for forensic analysis process, it is capable of avoiding unnecessary data processing. Lastly, since collected information is recorded in a normalized format, data input and output becomes much easier as well as it will be convenient to use for identification of collected information and analysis of data relationship.

• The Journal of Engineering Geology
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• v.29 no.2
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• pp.153-162
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• 2019

Rapid variations in the geometry (i.e., thickness) of the refractor and low velocities affect greatly the imaging of the reflectors of land seismic data. Conventional solutions to obtain the weathering models utilizes first break picking method, which requires time consuming steps and causes the human error in picking the first arrivals. A new interferometric approach (interferometric refraction statics, IRS) which utilizes the first arrival signal (S/N enhanced by refraction convolution stack) instead of first break picking, is tested in this study to the synthetic data from the velocity structure provided by surface geophysics (refraction, MASW) and borehole geophysics (tomography, SPS logging) for the Cheongju granitic bodies. The results of IRS approach are found to be better than the ones from conventional first break picking in terms of continuities and horizontal resolution of the reflectors. The unresolved long-wavelength statics in brute stack are much removed by IRS weathering correction and the overlying refractors (the base of shallow weathering zone) are incidentally delineated in the refraction convolution stack.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.4
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• pp.283-290
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• 2022

In this study, an IoT inspection system that can be linked with a server was developed using a gas timer and ESP-01 Wi-Fi module installed on a gas valve in the home. The server environment of the gas leak IoT inspection system was installed with APM (Apache, PHP, MySQL) to collect gas pressure data by generation so that leakage checks could be performed. In order to control the gas leak IoT inspection system, the app inventory was used to manage the gas leak check value in real time. In addition, user convenience has been enhanced so that membership management, WiFi settings, and leakage check values can be checked through mobile apps. In order to manage subscribers by region, the user list was checked by logging in in in the administrator mode so that the information on whether or not the leak test was conducted and the results could be provided. In addition, when the user presses the gas leak check button, the pressure is automatically checked, and the measured value is stored in the server, and when a gas leak occurs, the leakage check is performed after alarm and repair so that it can be used if normal. In addition, in order to prevent overlapping membership, membership management can be performed based on MAC addresses.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.5
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• pp.445-458
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• 1991

The literatures on meteorological disasters of which reported in Korea and abroad were reviewed and discussed in oilseed crops for refer to stable production and quality improvement of the crops. From the reviews, it was clarified that much of the reported disasters are almost same kinds as the other crops like reported in soybean and rice. However much of the disasters reported in oilseed crops were unconfirmed on their injury mechanisms or damage rate on yield loss and quality deteriorate comparing to the reports on soybean or rice. Among the meteorological disasters reported in oilseed crops, the disaters on sesame and groundnut were the most frequent in the numbers of report and water-flooding damage, drought damage, lodging damage in the kinds of disasters. Such kinds of the above disasters were leading to 90% yield loss in the most serious situation. To reduce the damage of meteorological disasters, it was suggested that the variety improvement of which highly resistant, and vinyl-mulching culture would be also an way to reduce water -logging and drought damage in sesame and groundnut in cultural practice. Further, it was indicated that the emphasis must be put on the oilseed crops to investigate and clarify the damage mechanisms, and reducing method of meteorological disasters in breeding and cultural practice.

• KIPS Transactions on Computer and Communication Systems
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• v.12 no.3
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• pp.111-118
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• 2023

Cyber attacks are increasing worldwide, and attacks on personal privacy such as CCTV and IP camera hacking are also increasing. If you search for IP camera hacking methods in spaces such as YouTube, SNS, and the dark web, you can easily get data and hacking programs are also on sale. If you use an IP camera that has vulnerabilities used by hacking programs, you easily get hacked even if you change your password regularly or use a complex password including special characters, uppercase and lowercase letters, and numbers. Although news and media have raised concerns about the security of IP cameras and suggested measures to prevent damage, hacking incidents continue to occur. In order to prevent such hacking damage, it is necessary to identify the cause of the hacking incident and take concrete measures. First, we analyzed weak account settings and web server vulnerabilities of IP cameras, which are the causes of IP camera hacking, and suggested solutions. In addition, as a specific countermeasure against hacking, it is proposed to add a function to receive a notification when an IP camera is connected and a function to save the connection history. If there is such a function, the fact of damage can be recognized immediately, and important data can be left in arresting criminals. Therefore, in this paper, we propose a method to increase the safety from hacking by using the connection notification function and logging function of the IP camera.