• 한국멀티미디어학회논문지
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• 제23권1호
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• pp.24-30
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• 2020

As the number of internet-connected appliances and the variety of IoT services are rapidly increasing, it is hard to protect IT assets with traditional network security techniques. Most traditional network log analysis systems use rule based mechanisms to reduce the raw logs. But using predefined rules can't detect new attack patterns. So, there is a need for a mechanism to reduce congested raw logs and detect new attack patterns. This paper suggests enterprise security management for IoT services using graph and network measures. We model an event network based on a graph of interconnected logs between network devices and IoT gateways. And we suggest a network clustering algorithm that estimates the attack probability of log clusters and detects new attack patterns.

• 한국환경복원기술학회지
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• 제2권3호
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• pp.32-37
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• 1999

There is a need to suggest the standards of selection on the cuttings, because the selection of the willow(Salix) cuttings is very important, which will be used as the bioengineering revegetation material to protect the slope by strengthening soil and preventing soil erosion under the bad site conditions. In this study, we measured the lengths and the diameters of original willow cuttings, the total numbers and the lengths of the new shoots and roots after 15 months since the experimental construction of the slope revegetation technology of biological engineering was conducted, and analyzed the correlation between the lengths and the diameters of willow cuttings and the lengths of new roots using the SPSS program. The results are as follows; First, the lower the elevation of tested slope was, the more the number of new shoots and the average lengths of new roots increased. Secondly, the ratio of underground parts and aboveground parts was 4.24 ~ 5.93 proving the fact that the willow(Salix) is one of the species deep rooted with developed underground parts. Thirdly, there is a strong correlation between the diameters of willow cuttings and the total lengths of new roots, whereas, there is no correlation between the lengths of willow cuttings and the total lengths of new roots. In conclusion, it is more efficient for the early rapid revegetation and slope stabilization to select willow cuttings with the biggest possible diameters than with the longest lengths as the slope revegetation materials of biological engineering.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2003년도 추계학술대회 논문집
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• pp.63-66
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• 2003

A new algorithm, CBIR (Correlation Based Image Registration) was proposed to improve the resolution of image registration for PSP (Pressure Sensitive Paint). The local displacement vectors were obtained by finding the displacement which maximizes the cross-correlation between two interrogation windows of 'wind-off' and 'wind-on' images. A recursive multigrid processing was employed to increase the non-linear spatial resolutions. The variations of image were precisely measured without identifying the control points.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1778-1782
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• 2004

A new algorithm, CBIR (Correlation-Based Image Registration) was proposed to improve the resolution of image registration for PSP (Pressure-Sensitive Paint). The local displacement vectors were obtained by finding the displacement which maximizes the cross-correlation between two interrogation windows of 'wind-off' and 'wind-on' images. A recursive multigrid processing was employed to increase the non-linear spatial resolutions. The variations of image were precisely measured without identifying the control points.

• 항공우주시스템공학회지
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• 제18권1호
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• pp.46-52
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• 2024

엔진 시운전실은 엔진의 성능 및 운용 특성 요구도를 적절하게 검증할 수 있도록 통제된 시험 환경을 제공해야 한다. 하지만 시운전 설비마다 구조 및 특성이 완전히 같을 수는 없기 때문에, 신규 시운전실은 기준 시운전실과의 Correlation 시험을 통해 시험 결과의 신뢰성을 검증하고 차이점을 보정하는 과정이 필요하다. 본 논문에서는 터보팬과 터보샤프트 엔진의 공통점과 차이점을 바탕으로 Correlation 시험을 수행할 때 고려사항들을 연구하였으며, 경험에 따른 Correlation 시험 절차의 예시를 제시하였다. 향후 본 연구가 엔진 종류에 따른 시험 설비의 인증 표준을 설정하는 것에 도움을 줄 것으로 기대한다.

• 한국운동역학회지
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• 제12권2호
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• pp.245-257
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• 2002

이 연구의 목적은 간단하고 실용적이며, 타당성, 신뢰성, 객관성이 높은 체전굴 유연성 측정 도구를 개발하는데 있으며, D여자 대학교의 스포츠학 전공 여대생 44명이 자발적으로 연구의 피검자로 참여하였다. 새 측정 도구의 신뢰도와 객관도 검사는 재검법의 평균 측정값을 사용하여 이원 혼합효과 모델에 의한 급내 상관 계수를 산출하였다. 검사자별 1차와 2차의 급내 상관 계수는 L은 R = .994, Y는 R=.993, 1차와 2차 검사의 L과 Y검사자간 급내 상관 계수는 R = .985, R=.986으로 모두 상관도가 아주 높은 것으로 나타났다. 새로 개발한 체전굴 측정 도구의 타당도 검증을 위하여 Leighton-flexometer-tests의 원리를 이용한 Takei 의 flexometer를 준거 검사 도구로 사용하였으며, 1차 검사와 2차 검사에서의 새로운 체전굴 유연성 측정 도구와 준거 검사 도구 측정값의 Pearson 적률 상관계수는 각각 r = .962와 r = .960로 1, 2차 검사 모두 아주 높은 상관도를 나타냈다. 결론적으로 본 연구에서 새로 개발한 체전굴 검사는 타당도, 신뢰도, 객관도가 매우 높고 실용적인 것으로 평가될 수 있음이 밝혀졌다.

• Advances in concrete construction
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• 제6권5호
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• pp.465-483
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• 2018

The most crucial factor determining the pumping performance of concrete is the characteristics of the lubricating layer formed between the pipe wall and the inner concrete. Thus, it is important to accurately identify the rheological properties of the lubricating layer to predict the pumping of concrete. In this study, a new method is proposed for measuring the rheological properties of the lubricating layer with improved convenience. To verify the new method, a pumping test was conducted with 337 m-long horizontal piping. The rheological properties of the lubricating layer were assessed by a previously verified method and the new method proposed in this study for a total of four concrete mixtures with design strength ranging from 27 MPa to 60 MPa. The correlation between the existing method and the new method in relation to the viscosity of the lubricating layer was determined, and it was possible to predict the pumping performance with an accuracy of about 88.5% using the viscosity of the lubricating layer obtained from this correlation.

• Earthquakes and Structures
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• 제8권5호
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• pp.957-976
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• 2015

Recently, two energy-based response parameters, i.e., the absolute and the relative elastic input energy equivalent velocity, have been receiving a lot of research attention. Several studies, in fact, have demonstrated the potential of these intensity measures in the prediction of the seismic structural response. Although some ground motion prediction equations have been developed for these parameters, they only provide marginal distributions without information about the joint occurrence of the spectral values at different periods. In order to build new prediction models for the two equivalent velocities, a large set of ground motion records is used to calculate the correlation coefficients between the response spectral values corresponding to different periods and components of the ground motion. Then, functional forms adopted in models from the literature are calibrated to fit the obtained data. A new functional form is proposed to improve the predictions of the considered models from the literature. The components of the ground motion considered in this study are the two horizontal ones only. Potential uses of the proposed equations in addition to the prediction of the correlation coefficients of the equivalent velocity spectral values are shown, such as the prediction of derived intensity measures and the development of conditional mean spectra.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.613-618
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• 2008

Because the flat dilatometer (DMT) is operated in appropriate strain level, it has been known as an adoptable in-situ tool to evaluate the compressibility of soils compare with other in-situ test tools, such as SPT and CPT. This study is concerned about prediction method of constrained modulus by DMT, and a series of DMT and consolidation tests are performed at Busan new-port, Yangsan and Noksan test sites. By comparing DMT results with lab tests, the suitability of constrained modulus correlation, which is suggested by Marchetti, is investigated in Busan clay and new correlation is suggested. In lab test result, the compression indices ($C_c$) of Busan clay are turned out to be 0.4~0.12, and the constrained moduli are found out 0.5MPa~3MPa and these are increase with depth. The predicted constrained moduli using Marchetti's correlation are turned out 0.5MPa~4MPa, and these are bigger than measured constrained moduli by lab tests. By analyzing lab test and DMT results, it is shown that the correlation coefficient ($R_M=M/E_D$) has a linear relationship with (1/$I_D$) in Busan.

• Restorative Dentistry and Endodontics
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• 제38권1호
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• pp.31-35
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• 2013

Objectives: This study compared the cyclic fatigue resistance of nickel-titanium (NiTi) files obtained in a conventional test using a simulated canal with a newly developed method that allows the application of constant fatigue load conditions. Materials and Methods: ProFile and K3 files of #25/.06, #30/.06, and #40/.04 were selected. Two types of testing devices were built to test their fatigue performance. The first (conventional) device prescribed curvature inside a simulated canal (C-test), the second new device exerted a constant load (L-test) whilst allowing any resulting curvature. Ten new instruments of each size and brand were tested with each device. The files were rotated until fracture and the number of cycles to failure (NCF) was determined. The NCF were subjected to one-way ANOVA and Duncan's post-hoc test for each method. Spearman's rank correlation coefficient was computed to examine any association between methods. Results: Spearman's rank correlation coefficient (${\rho}$ = -0.905) showed a significant negative correlation between methods. Groups with significant difference after the L-test divided into 4 clusters, whilst the C-test gave just 2 clusters. From the L-test, considering the negative correlation of NCF, K3 gave a significantly lower fatigue resistance than ProFile as in the C-test. K3 #30/.06 showed a lower fatigue resistance than K3 #25/.06, which was not found by the C-test. Variation in fatigue test methodology resulted in different cyclic fatigue resistance rankings for various NiTi files. Conclusions: The new methodology standardized the load during fatigue testing, allowing determination fatigue behavior under constant load conditions.