• Communications for Statistical Applications and Methods
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• 제27권1호
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• pp.141-148
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• 2020

We consider estimating the proportion of true null hypotheses in multiple testing problems. A traditional multiple testing rate, family-wise error rate is too conservative and old to control type I error in multiple testing setups; however, false discovery rate (FDR) has received significant attention in many research areas such as GWAS data, FMRI data, and signal processing. Identify differentially expressed genes in microarray studies involves estimating the proportion of true null hypotheses in FDR procedures. However, we need to account for unknown dependence structures among genes in microarray data in order to estimate the proportion of true null hypothesis since the genuine dependence structure of microarray data is unknown. We compare various procedures in simulation data and real microarray data. We consider a hidden Markov model for simulated data with dependency. Cai procedure (2007) and a sliding linear model procedure (2011) have a relatively smaller bias and standard errors, being more proper for estimating the proportion of true null hypotheses in simulated data under various setups. Real data analysis shows that 5 estimation procedures among 9 procedures have almost similar values of the estimated proportion of true null hypotheses in microarray data.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 지반공학 공동 학술발표회
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• pp.389-394
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• 2005

In this study we carried out to evaluate the salinity concentration and volumetric water content of unsaturated soil column using frequency domain Reflectometry with vector network analyzer (FDR-V) measurement system. All of experiments were considered to the effect of temperature which ranges from l0$^{\circ}C$ to 50$^{\circ}C$ increasing the interval of l0$^{\circ}C$ controlled by the constant temperature container. From the results the responses of complex dielectric constant which consist of the real part and imaginary parts have the effect of volumetric water content and concentration of salinity at 1GHz. Use of derived equations (1) and (2) can be calculated the physical parameters such as volumetric water content and salinity concentration of unsaturated media by the responses of complex dielectric constant.

• 한국정보과학회논문지:소프트웨어및응용
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• 제31권9호
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• pp.1218-1225
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• 2004

S/KEY 시스템은 공격자의 패스워드 재공격을 방지하기 위해 제안되었다. 하지만 S/KEY 시스템은 공격자가 자신이 가지고 있는 사전에서 패스프레이즈(passphrase)를 유추해 낼 경우, 결국 인증을 하는데 필요한 일회용 패스워드를 알아낼 수 있는 취약점을 가지고 있다. 이 논문에서는 passphrase에 대한 사전공격을 방지하기 위해 EKE(Encrypted Key Exchange) 프로토콜을 적용한 새로운 S/KEY 시스템을 제시한다. 그리고 새로 제안된 S/KEY 시스템의 안전성을 검증하기 위해 Casper와 CSP로 프로토콜을 명세하고, FDR 모델 체커를 이용하여 그 안전성을 검증하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권11호
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• pp.4028-4049
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• 2014

Attribute-based encryption (ABE) is a promising cryptographic primitive for implementing fine-grained data sharing in cloud computing. However, before ABE can be widely deployed in practical cloud storage systems, a challenging issue with regard to attributes and user revocation has to be addressed. To our knowledge, most of the existing ABE schemes fail to support flexible and direct revocation owing to the burdensome update of attribute secret keys and all the ciphertexts. Aiming at tackling the challenge above, we formalize the notion of ciphertext-policy ABE supporting flexible and direct revocation (FDR-CP-ABE), and present a concrete construction. The proposed scheme supports direct attribute and user revocation. To achieve this goal, we introduce an auxiliary function to determine the ciphertexts involved in revocation events, and then only update these involved ciphertexts by adopting the technique of broadcast encryption. Furthermore, our construction is proven secure in the standard model. Theoretical analysis and experimental results indicate that FDR-CP-ABE outperforms the previous revocation-related methods.

• 한국농공학회논문집
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• 제53권4호
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• pp.1-9
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• 2011

Forest area covers 64 % of the national land of Korea and the forest plays a pivotal role in the hydrological process such as flood, drought, runoff, infiltration, evapotranspiration, etc. In this study, soil moisture monitoring for conifer forest in experimental forest of Seoul National University has been conducted using FDR (Frequency Domain Reflection) for 6 different soil layers, 10, 20, 30, 60, 90 and 120 cm during 2009~2010, and precipitation data was collected from nearby AWS (Automatic Weather Station). Soil moisture monitoring data were used to estimate soil moisture recession constant (SMRC) for analyzing soil moisture recession characteristics. From the results, empirical soil moisture recession equations were estimated and validated to determine the feasibility of the result, and soil moisture contents of measured and calculated showed a similar tendency from April to November. Thus, the results can be applied for soil moisture estimation and provided the basic knowledge in forest soil moisture consumption. Nevertheless, this approach demonstrated applicability limitations during winter and early spring season due to freezing and melting of snow and ice causing peculiar change of soil moisture contents.

• 한국항공우주학회지
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• 제46권11호
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• pp.961-968
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• 2018

항공기 시현계통은 항공기 운영에 필요한 다양한 정보를 통합하여 조종사에게 시현한다. 시현계통에서 소프트웨어 결함이 발생되면 정확하지 않은 정보가 조종사에게 시현될 수 있기 때문에 항공기의 운영에 심각한 영향을 미칠 수 있다. 따라서 시현계통의 개발 중에 지상시험과 비행시험을 통해 발생 가능한 소프트웨어 결함을 식별하고 제거하려고 노력하고 있다. 본 연구는 비행시험 자료를 이용하여 시현계통의 소프트웨어 결함 분석을 지원하는 도구인 FDR(Flight Data Replay)을 제시한다. 이 도구는 항공기 임무컴퓨터와 연동되어 실시간으로 동작한다. 그리고 시현소프트웨어에 비행시험 자료를 적용하여 시현장치에 나타나는 기능적인 오류상황을 재현한다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 가을 학술논문 발표대회
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• pp.109-110
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• 2022

Currently, interest in the quality of concrete is increasing. Among the important factors for evaluating the quality of concrete, interest in unit-water content is also increasing. Currently, the air-meter method, the microwave oven drying method, the capacitance method, and the microwave penetration method are used to measure the unit-water content of concrete.. Among the above methods, except for the microwave method, the measurement method is complicated, portability is reduced, and economic efficiency is reduced. This research aims to measure a unit-water content by using a Frequency Domain Reflectometry(FDR) sensor that is economical, simple to measure, and portable among microwave methods. In addition, it is an experimental study to determine the accuracy of unit-water content using a single input residual model during deep learning to solve the limitations of the FDR sensor.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 가을학술발표대회논문집
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• pp.173-174
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• 2023

In this study, unit-water content was measured using a frequency domain reflecometry(FDR) sensor that complements the problems of the existing unit-water content measurement method to evaluate the unit-water content affecting the workability, durability, and quality of high strength concrete. The experiment used the unit-water content of high strength concrete as a variable, and the accuracy and probability distribution of the unit-water content measured through deep learning were analyzed for the output value output through the FDR sensor. In the case of the unit-water content predicted by deep learning analysis, a high accuracy and high distribution of more than 93% were found within the error range of ± 10 kg/m³. In the future, research is needed to secure high reliability by utilizing data obtained through experiments with various variables.

• 생물정신의학
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• 제25권3호
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• pp.60-71
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• 2018

Objectives A growing body of evidence has suggested that morphologic changes in cerebellum may be implicated with pathophysiology of major depressive disorder (MDD). The aim of this study is to investigate a difference in the volume and cortical thickness of the specific region of cerebellum between patients with MDD and healthy controls (HC). Methods A total of 127 patients with MDD and 105 HC participated in this study and underwent T1-weighted structural magnetic resonance imaging. We analyzed volume and cortical thickness of each twelve cerebellum regions divided by left and right and the volume and cortical thickness of the whole cerebellum from T1-weigted image of participants. One-way analysis of covariance was used to investigate the volume and cortical thickness difference of total and specific regions between two groups adjusting for age, gender, medication, and total intracranial cavity volume. Results We found that the patients with MDD had significantly greater volume in the left cerebellum lobule III region [false discovery rate (FDR)-corrected p = 0.034] compared to HC. Also, our findings indicate that cortical thickness of left lobule VIIB (FDR-corrected p = 0.032) and lobule VIIIB (FDR-corrected p = 0.032) are significantly thinner in the patients with MDD compared with the HC. No significant volume and cortical thickness differences were observed in other sub-regions of the cerebellum. The volumes and cortical thickness of whole cerebellum between patients with MDD and HC did not differ significantly. Conclusions We observed the region-specific volume and cortical thickness difference in cerebellum between the patients with MDD and HC. The results of our study implicate that the information about structural alterations in cerebellum with further replicative studies might provide a stepping stone toward a specific marker to diagnose MDD.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2005년도 가을 학술발표논문집 Vol.32 No.2 (1)
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• pp.91-93
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• 2005

무선주파수 식별자(RFID: Radio Frequency Identification)의 연구에 있어 보안에 관한 부분은 학계 및 개발자들에게 중요한 부분이다. 특히 기술적인 이슈인 개체인중을 통한 데이터의 보안은 아직도 신뢰성을 얻지 못하고 있다. 본 논문에서는 RFID 기반 네트워크 시스템의 취약성을 분석하고 정형적 방법론의 적용사례를 통해 적용가능성을 타진해 보고자 한다.