• 한국도로학회논문집
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• 제20권2호
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• pp.35-44
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• 2018

PURPOSES : The purpose of this research is to analyze the characteristics of panels that affect the evaluating results of riding quality and to evaluate the appropriateness of roughness management criteria based on ride comfort satisfaction. METHODS : In order to analyze the influence of panel characteristics of riding quality, 33 panels, consisting of civilians and experts, were selected. Also, considering the roughness distribution of the expressway, 35 sections with MRI ranging from 1.17 m/km to 4.65 m/km were selected. Each panel boarded a passenger car and evaluated the riding quality with grades from 0 to 10, and assessed whether it was satisfied or not. After removing outlier results using a box plot technique, 964 results were analyzed. An ANOVA was conducted to evaluate the effects of panel expertise, age, driving experience, vehicle ownership, and gender on the evaluation results. In addition, by using the receiver operating characteristics (ROC) curve, the MRI value, which can most accurately evaluate the satisfaction with riding quality, was derived. Then, the compatibility of MRI was evaluated using AUC as a criterion to assess whether the riding quality was satisfactory. RESULTS : Only the age of the panel participants were found to have an effect on the riding quality satisfaction. It was found that satisfaction with riding quality and MRI are strongly correlated. The satisfaction rate of roughness management criteria on new (MRI 1.6 m/km) and maintenance (MRI 3.0 m/km) expressways were 95% and 53%, respectively. As a result of evaluating the roughness management criteria by using the ROC curve, it was found that the accuracy of satisfaction was the highest at MRI 3.1-3.2 m/km. In addition, the AUC of the MRI was about 0.8, indicating that the MRI was an appropriate index for evaluating the riding quality satisfaction. CONCLUSIONS : Based on the results, the distribution of the panels' age should be considered when panel rating is conducted. From the results of the ROC curve, MRI of 3.0 m/km, which is a criterion of roughness management on maintenance expressways, is considered as appropriate.

• 한국전자통신학회논문지
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• 제10권6호
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• pp.665-670
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• 2015

본 논문은 마이크로웨이브 수신기 구성을 위한 광대역 RF 증폭기를 설계 및 제작하였다. 제안한 광대역 RF 증폭기는 수신된 신호의 안정적인 증폭을 위하여 소스단자에 연결되는 비아까지 EM설계를 하였으며, 능동소자의 소오스(Source) 측이 이상적인 접지(GND)로 동작함에 따라 발진하는 요소를 최소화 하여 광대역에서 일정한 이득 특성 및 안정적인 증폭특성을 얻도록 하였다. 상용 GaAs FET를 사용하고, 광대역 마이크로웨이브 수신기의 IF 주파수 대역인 720 MHz, 4,595 MHz와 6,035 MHz에서 동작하도록 입력 및 출력 정합회로를 구성하였다. 제작 및 측정결과 500 MHz ~ 7 GHz의 광대역 특성을 나타내었으며, 전압이득은 737.5 MHz에서 6.0575 GHz까지 10.635 dB ~ 13.129 dB, 기본파와 제2차 고조파 사이에서 20 dBc 이상의 고조파 억압특성을 나타내었다.

• 응용통계연구
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• 제32권5호
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• pp.653-669
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• 2019

뉴미디어의 등장과 발달로 인해, 과거 미디어의 대부분을 차지한 종이신문의 이용량이 점차 줄어들어 종이신문의 정기구독률이 2016년 14%로 매우 저조하게 나타났다. 따라서 본 연구는 종이신문 정기구독 여부에 영향을 미치는 열독자 요인을 파악하고자 수행되었다. 이를 위해 한국 언론 진흥재단의 2016년과 2017년의 언론수용자 의식조사의 자료를 분석에 사용하였다. 열독자의 성별, 연령, 학력, 가구소득, 열독일수, 열독시간, 열독분량을 열독자의 특성으로 지정하였으며, 정기구독 여부에 열독자의 어떠한 특성이 영향을 미치는지 알아보기 위해 다중 로지스틱 회귀를 적합하고 해석하였다.

• 수산해양기술연구
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• 제48권3호
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• pp.235-241
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• 2012

The efficiency tests of automatic positioning transmitter (APT) using satellite on life jacket were carried out to minimize casualties of fishermen and to make system optimization for effective SAR (Search and Rescue) operation. As the result of the tests, average position was equaled on the comparison between SPOT using low earth orbit satellite and DGPS (Differential Global Positining System), but standard deviation of DGPS for latitude and longitude were 66.4% and 46.3% smaller than those of SPOT. The position precision of SPOT was almost two times lower than LGT using geostationary satellite to compare 95% circular error probability. However, the success rate of receiver for SPOT was revealed as 86.5~94.1% on the experiments in the South Sea and the West Sea and it was 4.5 times higher than LGT. Therefore, SPOT is expected to contribute greatly to the rapid rescue of victim.

• 대한전자공학회논문지TC
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• 제46권12호
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• pp.72-81
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• 2009

본 논문에서는 미국 FCC에서 최근 소개한 수신기 중심적 간섭 메트릭 (receiver-centric Interference metric)인 간섭온도 (interference temperature (IT)) 기반의 간섭해석모델과 이에 기반을 둔 주파수 공유 기법을 검토 제안한다. 기존의 단일 cognitive radio (CR) 사용자 (혹은 부사용자, secondary user) 주파수 공유 방안을 실제 다수의 부사용자를 고려한 주파수 공유 방안으로 확장 제시한다. 또한 주사용자 (primary user)가 시간 축 상에 랜덤하게 발생 (ON/OFF)하는 실제 운용환경을 감안한 새로운 간섭온도 모델을 제시하고 이를 이용하여 CR 용량을 정량적으로 분석한다. CR 용량은 시간 축 상의 유휴 슬롯 채널 할당을 위한 순시용량과 순시용량을 평균한 평균용량으로 구분되며 공유절차상에 이를 적절히 이용 채널을 할당한다. 제안된 공유 절차는 기존의 공유 절차와는 달리 주사용자로 부터 별도의 스펙트럼 센싱 정보를 요구하지 않으며 전송속도 및 채널특성에 따라 적응적으로 주파수 파라미터의 변경이 가능하다. 시뮬레이션을 통해 제안한 주파수 공유 절차의 타당성을 검증한다.

• 조명전기설비학회논문지
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• 제24권11호
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• pp.30-41
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• 2010

In this study we propose a new texture feature extraction method based on an estimation of the brightness and structural uniformity of CT images representing the important characteristics for emphysema recognition. The Center-Symmetric Local Binary Pattern (CS-LBP) is first used to combine gray level in order to describe the brightness uniformity characteristics of the CT image. Then the gradient orientation difference is proposed to generate another CS-LBP code combining with gray level to represent the structural uniformity characteristics of the CT image. The usage of the gray level, CS-LBP and gradient orientation differences enables the proposed method to extract rich and distinctive information from the CT images in multiple directions. Experimental results showed that the performance of the proposed method is more stable with respect to sensitivity and specificity when compared with the SGLDM, GLRLM and GLDM. The proposed method outperformed these three conventional methods (SGLDM, GLRLM, and GLDM) 7.85[%], 22.87[%], and 16.67[%] respectively, according to the diagnosis of average accuracy, demonstrated by the Receiver Operating Characteristic (ROC) curves.

• 말소리와 음성과학
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• 제4권3호
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• pp.103-110
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• 2012

In this paper, a target signal detection method using multiple signal classification (MUSIC) algorithm is proposed. The MUSIC algorithm is a subspace-based direction of arrival (DOA) estimation method. Using the inverse of the eigenvalue-weighted eigen spectra, the algorithm detects the DOAs of multiple sources. To apply the algorithm in target signal detection for GSC-based beamforming, we utilize its spectral response for the DOA of the target source in noisy conditions. The performance of the proposed target signal detection method is compared with those of the normalized cross-correlation (NCC), the fixed beamforming, and the power ratio method. Experimental results show that the proposed algorithm significantly outperforms the conventional ones in receiver operating characteristics (ROC) curves.

• 공학교육연구
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• 제13권5호
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• pp.36-40
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• 2010

The vehicle oriented block box system based on the u-healthcare and the human-free guard functions is developed in this paper. We also suggested the design philosophies, ideas, and analyzed the performance of the suggested system. The developed vehicle oriented black box system has some characteristics such as; 1) detects the dangerous situation by ultrasonic sensor in advance, and stores the situation information of the neighborhood of the vehicle to the imbedded SD memory card if the dangerous situation may be occurred in the parked vehicle; 2) detects the present location and speed information of the vehicle by GPS receiver and 3-axes acceleration sensor, and stores the information to the SD memory card periodically if the vehicle is running; 3) measures the dioxide carbon in the vehicle inside using $CO_2$ sensor, and forces the ventilation motor of the vehicle to operate and maintains the driver's health if the measured level is more than standard health requirements; 4) provides the stored vehicle's operating information to the driver by GUI (Graphical User Interface) based touch LCD monitor.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권10호
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• pp.5159-5178
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• 2018

Network Intrusion detection is a rapidly growing field of information security due to its importance for modern IT infrastructure. Many supervised and unsupervised learning techniques have been devised by researchers from discipline of machine learning and data mining to achieve reliable detection of anomalies. In this paper, a deep convolutional neural network (DCNN) based intrusion detection system (IDS) is proposed, implemented and analyzed. Deep CNN core of proposed IDS is fine-tuned using Randomized search over configuration space. Proposed system is trained and tested on NSLKDD training and testing datasets using GPU. Performance comparisons of proposed DCNN model are provided with other classifiers using well-known metrics including Receiver operating characteristics (RoC) curve, Area under RoC curve (AuC), accuracy, precision-recall curve and mean average precision (mAP). The experimental results of proposed DCNN based IDS shows promising results for real world application in anomaly detection systems.

• 전자공학회논문지A
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• 제33A권4호
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• pp.78-83
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• 1996

A timing recovery circuit of 10 Gbit/s optical receiver is described. The circuit consists of a passive NRZ-to-PRZ circuit, a dielectric resonator filter (DRF) and a narrow band amplifier, which for the first time adopted a temperature compensation technique using the tempareature characteristics of DR. The experimental results showed an output clock phase variation of less than ${\pm}$6 degree over the operating temperature range form 0$^{\circ}C$ to 75$^{\circ}C$ and measured maximum rms jitters of less than 2 phs with the resonance detunings of up to ${\pm}$10 MHz. These experimental results show that the circuit is a suitable for 10 Gbit/s lightwave transmission system.