• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.586-589
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• 2012

표절과 관련된 이슈가 주목받고 있는 상황에서 표절을 검출하는 방법에 대한 연구가 활발히 진행되고 있다. 일반적으로 표절구간 검출을 위해 복잡한 자연어처리와 같은 의미론적 접근방법이 아닌 비교적 단순한 어휘기반의 문자열 처리 방법을 사용한다. 대표적인 방법으로는 지문법 (Fingerprinting)과 서열정렬 (Sequence alignment) 등이 있다. 하지만 이 방법들을 이용하여 대용량 문서에 대한 표절검사를 수행하기에는 시공간적 복잡도의 문제가 발생한다. 본 논문에서는 이러한 단점을 극복하기 위해 NGS (Next Generation Sequencing)에서 사용하는 BWT (Burrows-Wheeler Transform)[1]를 이용한 탐색방법을 응용한다. 또한 부분표절구간을 검출하고 정확도를 향상시키기 위해 질의문서를 분할하여 작은 조각으로 만든 뒤, 조각들에 대한 질의탐색을 수행한다. 본 논문에서는 질의문서를 분할하는 두 가지 방법을 소개한다. 두 가지 방법은 k-mer analysis를 이용한 방법과 random-split analysis를 이용한 방법으로, 각 방법의 장단점을 실험을 통해 분석하고 실제 부분표절구간의 검출 정확도를 측정하였다.

• Journal of the Korean Society of Safety
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• v.37 no.3
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• pp.1-8
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• 2022

Workplace accidents are common while working at elevations. Thus, various safety measures such as safety handrails and horizontal safety nets are implemented to prevent falls. The minimum safety measure is the lifeline installation. However, because its standards have not been clearly established, it is often misused, resulting in inappropriate knot methods that increase the chance of accidents while working at elevations. Therefore, clarifying the appropriate usage methods or criteria for the various lifelines is required in the field. This study proposed an appropriate installation method by experimentally and numerically evaluating the change in strength according to the fixed knot lifeline method. In addition, three knot methods were specified for each material. The results obtained are expected to contribute to lessening falls through the establishment of lifeline installation standards and the development of appropriate parts.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.11a
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• pp.322-325
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• 2022

삼킴 장애 환자는 뇌졸중, 치매, 외상성 뇌손상, 파킨슨병, 암이 주요 원인으로 급속히 증가하고 있다. 특히 고령화 사회가 되면서 더욱 삼킴 장애 환자는 늘어날 것으로 전망하고 있다. 고령 환자의 삼킴 이상의 진단을 위해 가장 많이 사용하고 있는 검사법으로는 비디오 조영 삼킴 검사(VFSS)이다. VFSS는 진단에 있어서 숙련된 전문의가 필요하기 때문에 대학병원 급에서 주로 시행하며, 고령 환자에게는 분석 결과를 상담받을 때까지 오랜 시간을 소요해야하는 문제점들이 있다. 본 논문에서는 삼킴 장애 진단을 위한 의료영상 관리 및 라벨링 시스템에 대해서 기술한다. 이를 구현하기 위해 서버에서 대용량 멀티프레임 영상을 성능 저하 없이 핸들링 하고 라벨링 데이터 생성을 위한 라벨링 툴을 구현하였다. 차후 라벨링 데이터를 생성하고 학습을 통하여 삼킴 장애 진단을 위한 인공지능 모델을 개발하고자 한다.

• 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 Energy Engineering
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• v.18 no.1
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• pp.49-55
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• 2009

Occurrence of hydrogen embrittlement could be one of the main obstacles for using structural equipment under hydrogen environment. It is required to develop assessment methods of hydrogen embrittlement for the metals used in production, storage, transmission and application utilities of hydrogen. The most probable method of hydrogen mass transmission is using existing natural gas pipeline. Base or weld part of the pipeline can be damaged by mixed gas of hydrogen in the pipeline. In this study small punch (SP) testing was employed to evaluate the hydrogen embrittlement behavior for a line pipe steel (API X65) with electrochemically hydrogen charged specimens. Results showed that the SP test can be a good candidate test method for hydrogen damage evaluation method. Strength of steel is known to be decreased with the level of hydrogen charging. However, for API X65 steel base metal need in this study, the effect of hydrogen to strength was not significant. It can be negligible regardless of the hydrogen contents in the steel. With this test different strength levels with various hydrogen charging conditions were observed. It can also be anticipated that more sensitive evaluation of material behavior be obtainable by the SP test method.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.37 no.1
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• pp.9-16
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• 2024

Using the proper orthogonal decomposition (POD) based intrusive reduced order model (ROM), the total degrees of freedom of the structural system can be significantly reduced and the critical time step satisfying the conditional stability increases in the explicit time integrations. In this study, therefore, the changes in the critical time step in the explicit time integrations are investigated using both the POD-ROM and Voronoi-cell lattice model (VCLM). The snapshot matrix is composed of the data from the structural response under the arbitrary dynamic loads such as seismic excitation, from which the POD-ROM is constructed and the predictive capability is validated. The simulated results show that the significant reduction in the computational time can be achieved using the POD-ROM with sufficiently ensuring the numerical accuracy in the seismic analyses. In addition, the validations show that the POD based intrusive ROM is compatible with the Voronoi-cell lattice based explicit dynamic analyses. In the future study, the research results will be utilized as an elemental technology for the developments of the real-time predictive models or monitoring system involving the high-fidelity simulations of structural dynamics.

• Explosives and Blasting
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• v.22 no.1
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• pp.33-43
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• 2004

In this study, a comparison was made between the resulting behaviors of scaled model test and particle flow analysis for blasting demolition of a reinforced concrete structure. For the test and analysis, a progressive failure of a five-story structure was considered. The dimension analysis was carried out to properly scale down the real structure into the laboratory size. The test model was made of the mixture of gypsum, sand and water along with soldering lead to analogy reinforcing steel bars. The ratio of mixing components was chosen to best represent the scaled down strength and deformation modulus. The columns and girders of the structure were precasted in the laboratory and assembled right before the blasting test. The numerical analysis of the blasting demolition was carried out using PFC2D (Particle Flow Analysis 2-Dimension by Itasca). The results of the blasting of concrete lahmen structure showed roughly identical demolition behavior between scaled model test and numerical test. For the blasting of the reinforced concrete structure, the results were more identical and closer to the real demolition behavior, since the demolition behavior was better represented in this case due to the increased tensile strength of the component.

• The KIPS Transactions:PartD
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• v.13D no.7 s.110
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• pp.901-908
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• 2006

With the development of wireless communication techniques and mobile environment we are able to transmit data between mobile systems without restriction of time and space. Recently, researches on the data communication between mobile systems have focused on a small amount of sending out or receiving data and data synchronization at a fixed server and mobile clients in mobile environment. However, two more servers should be able to move mutual independently, information is shared with other systems, and data is synchronized in the special environment like a battlefield situation. Therefore, we propose a data synchronization method between systems moving mutual independently in mobile environment. The proposed method is an optimization solution to data propagation path between servers that considers limited bandwidth and process of data for disconnection communication. In addition, we propose a data reduction method that considers importance and sharing of information in order to reduce data transmission between huge servers. We verified the accuracy of data after accomplishing our data synchronization method by applying it in the real world environment. Additionally, we showed that our method could accomplish data synchronization normally within an allowance tolerance when we considered data propagating delay time by server extension.

• Tunnel and Underground Space
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• v.14 no.1
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• pp.54-68
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• 2004

In this study, scaled model tests were performed on blasting demolition of reinforced concrete structures and the experimental results were analyzed in comparison with the results of numerical analysis. The tests were designed to induce a progressive collapse, and physical properties of the scaled model were determined using scale factors obtained ken dimension analysis. The scaled model structure was made of a mixture of plaster, sand and water at the ratio determined to yield the best scaled-down strength. Lead wire was used as a substitute for reinforcing bars. The scaled length was at the ratio of 1/10. Selecting the material and scaled factors was aimed at obtaining appropriately scaled-down strength. PFC2D (Particle Flow Code 2-Dimension) employing DEM (Distinct Element Method) was used for the numerical analysis. Blasting demolition of scaled 3-D plain concrete laymen structure was filmed and compared to results of numerical simulation. Despite the limits of 2-D simulation the resulting demolition behaviors were similar to each other. Based on the above experimental results in combination with bending test results of RC beam, numerical analysis was carried out to determine the blasting sequence and delay times. Scaled model test of RC structure resulted in remarkably similar collapse with the numerical results up to 900㎳ (mili-second).

• KIPS Transactions on Computer and Communication Systems
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• v.1 no.2
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• pp.71-78
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• 2012

The digital tachograph is a device that automatically records speed and distance of a vehicle, together with the driver's activity and vehicle status at an accident. It records vehicle speed, break status, acceleration, engine RPM, longitude and latitude of GPS, accumulated distance, and so on. European Commission regulation made digital tachographs mandatory for all trucks from 2005. Republic of Korea made digital tachographs mandatory for all new business vehicles from 2011 and is widening the range of vehicles that must install digital tachographs year by year. This device is used to analyze driver's daily driving information and car accidents. Under a car accident that makes the device reliability unpredictable, it is very important to store driving information with maximum reliability for its original mission. We designed and implemented a practical digital tachograph. This paper presents a storage scheme that consists of a first storage device with small capacity at a high reliability and a second storage device with large capacity at a low cost in order to reliably records data with a hardware at a low cost. The first storage device records data in a SLC NAND flash memory in a log-structured style. We present a reverse partial scan that overcomes the slow scan time of log-structured storages at the boot stage. The scheme reduced the scan time of the first storage device by 1/50. In addition, our design includes a scheme that fast stores data at a moment of accident by 1/20 of data transfer time of a normal method.