• International Journal of Computer Science & Network Security
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• 제24권2호
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• pp.136-142
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• 2024

Haze is a very common phenomenon that degrades or reduces the visibility. It causes various problems where high quality images are required such as traffic and security monitoring. So haze removal from images receives great attention for clear vision. Due to its huge impact, significant advances have been achieved but the task yet remains a challenging one. Recently, different types of deep generative adversarial networks (GAN) are applied to suppress the noise and improve the dehazing performance. But it is unclear how these algorithms would perform on hazy images acquired "in the wild" and how we could gauge the progress in the field. This paper aims to bridge this gap. We present a comprehensive study and experimental evaluation on diverse GAN models in single image dehazing through benchmark datasets.

• International journal of advanced smart convergence
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• 제6권2호
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• pp.16-23
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• 2017

In contemporary modern society, people are constantly exposed to many kinds of noise, such as that from machinery, aircraft, construction sites, or road traffic. Noise is considered one of the most indispensable and influential parts of human life. This study investigates the acoustic characteristics of noise transfer from external sources to the human ear. For this study, we measured and analyzed various types of noise environments, installed monitoring speakers in a semi-anechoic room, and conducted intentional noise-filled experiments. In this environment, the size of the sounds generated by use of a portable device was also measured and the SNR (signal to noise ratio) calculated to study the influence of the noise. As sound is transmitted to the ear and the human body, it affects not only auditory damage but also other parts of the body. In this paper, we propose a proper SNR for noise emitted by portable IT equipment to prevent hearing loss when IT equipment is used.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2012년도 춘계학술발표대회
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• pp.429-431
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• 2012

Vehicle-logo recognition technology is very important in vehicle automatic recognition technique. The intended application is automatic recognition of vehicle type for secure access and traffic monitoring applications, a problem not hitherto considered at such a level of accuracy. Vehicle-logo recognition can improve Vehicle type recognition accuracy. So in this paper, introduces how to vehicle-logo recognition. First introduces the region of the license plate by algorithm and roughly located the region of car emblem based on the relationship of license plate and car emblem. Then located the car emblem with precision by the distance of Hausdorff. On the base, processing the region by morphologic, edge detection, analysis of connectivity and pick up the PCA character by lowing the dimension of the image and unifying the PCA character. At last the logo can be recognized using the algorithm of support vector machine. Experimental results show the effectiveness of the proposed method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.39-41
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• 2002

Management of internal Internet servers is increasingly becoming an important task. According to meet this requirement, they use service log analysis tools and network monitoring tools. But these are not enough to produce advanced management information considering contents of Internet services. Therefor we propose a system and let it detect Internet server systems existing in internal network and individuate those systems with providing profile. Internet server profile includes system's basic information, network traffic information, and Internet service usage information.

• Smart Structures and Systems
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• 제6권5_6호
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• pp.461-480
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• 2010

This paper analyses the data collected from the $2^{nd}$ Jindo Bridge, a cable-stayed bridge in Korea that is a structural health monitoring (SHM) international test bed for advanced wireless smart sensors network (WSSN) technology. The SHM system consists of a total of 70 wireless smart sensor nodes deployed underneath of the deck, on the pylons, and on the cables to capture the vibration of the bridge excited by traffic and environmental loadings. Analysis of the data is performed in both the time and frequency domains. Modal properties of the bridge are identified using the frequency domain decomposition and the stochastic subspace identification methods based on the output-only measurements, and the results are compared with those obtained from a detailed finite element model. Tension forces for the 10 instrumented stay cables are also estimated from the ambient acceleration data and compared both with those from the initial design and with those obtained during two previous regular inspections. The results of the data analyses demonstrate that the WSSN-based SHM system performs effectively for this cable-stayed bridge, giving direct access to the physical status of the bridge.

• 한국컴퓨터정보학회논문지
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• 제16권12호
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• pp.227-234
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• 2011

노트북 컴퓨터, 스마트폰 및 기타 단말기 등 네트워크를 제공하는 모바일 기기가 증가함에 따라 무선 인터넷에 대한 많은 기술들이 발전하고 있다. IEEE 802.11은 흔히 무선랜, 와이파이라고 부르는 좁은 지역을 위한 컴퓨터 무선 네트워크에 사용되는 기술로 일상생활에서 쉽게 접할 수 있으며 액세스 포인트(AP)와 네트워킹이 가능하지만 무선랜은 보안에 취약하고 제 3자가 AP에 불법으로 접속하여 패킷을 조작하거나 정보를 빼낼 가능성이 있어 주의가 필요하다. AP (Access Point)는 무선 환경을 제공하는 기기로써 카페와 같은 공공장소에 설치되고 있다. AP는 무선인터넷을 더 편리하게 사용할 수 있게 한다. 하지만 IEEE 802.11 가진 많은 취약점 때문에 공격자는 AP와의 통신을 쉽게 도청할 수 있다. 따라서 본 논문에서는 무선랜 환경에서 패킷 분석을 위한 모니터링 시스템을 설계하고 구현한 것으로서 최근 스마트폰의 보급 확대에 따른 모바일상의 보안문제가 크게 대두되고 있는 시점에서 주변에 어떤 AP와 스테이션이 통신을 하며, AP의 정보를 캡처하여 보안상의 취약점을 알아내고 분석할 수 있는 무선 네트워크 패킷을 분석을 위한 모니터링 시스템을 개발하고자 하였다.

• 보건행정학회지
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• 제11권3호
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• pp.71-88
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• 2001

The purpose of this study is to analyze the cost-effectiveness of four medications for treating and preventing osteoporosis -HRT therapy(conjugated equine estrogen 0.625mg for 25 days and medroxyprogesterone acetate 5mg for 01112 days), Alendronate(10mg and 5mg), Active Vitamin D(Calcitriol), and Calcium. Total costs include the direct medical cost -examination fee, consultation fee, prescription fee, fee for preparing medications, and the price of pharmaceuticals- and the indirect cost of patients such as traffic expenses and time cost. In addition, the costs of monitoring in adverse reactions are added. The effects of four medications are expressed as BMD(Bone Mineral Density) percent change measured by DEXA(Dual Energy X-ray Absorptiometry) in lumbar spine(L2-L4) and femoral neck site. A mixed model based on meta analysis provides the estimates of effectiveness, which are then appled to the hypothetical cohort consisting of postmenopausal women at the age of 50-59. HRT therapy is the most cost-effective medication at 172,433.64 won (lumbar spine site) and 546,328.28 won (femoral neck site) per BMD percent change for osteoporosis. Alendronate 10mg is more cost-effective than Alendronate 5mg as 345,971.23 won and 378,441.63 won per lumbar BMD percent change at 0.991ｇ/$cm^2$, respectively. Alendronate 10mg is more cost-effective than Alendronate 5mg as 1,329,257.89 won and 1,467,291.23 won per femoral neck BMD percent change at 0.834ｇ/$cm^2$, respectively.

• 한국항해항만학회지
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• 제43권4호
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• pp.250-255
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• 2019

본 연구는 유선, 어선 등이 관제대상으로 확대됨에 따라 해당 선박이 VTS(Vessel Traffic Service) 관제사에게 미치는 충돌사고 위험도를 분석하는 데 목적이 있다. 이를 위해 VTS 관제사를 대상으로 설문을 하고 소형선박의 범위를 정하여 부산 VTS 관제 구역을 항해하는 일반상선과 소형선박의 침로 등을 3일간 조사하였다. 이를 VTS 관제사 관점에서의 충돌위험 평가모델(CoRI)로 위험도를 구한 결과, 침로 편차에 따른 위험도의 증가 감소 패턴은 비슷하였고, 최댓값과 최솟값은 큰 차이가 없었다. 또한 대부분 VTS 관제사는 선박근접상황에 대해 안전하게 관제할 수 있는 최소 시간으로 3분이 필요하다 응답하였는데, 소형선박의 충돌위험도는 3분의 시간 동안 매우 급격하게 위험도 변화를 보여 VTS 관제사의 업무량 증가와 집중도 저하 우려가 있다고 판단된다. 본 연구는 소형선박의 관제대상 포함 여부가 VTS 관제사에게 미치는 영향을 충돌위험도로 검토한 것으로, 향후 다양한 사례를 통한 CoRI 모델의 각 지수에 대한 분석과 검증을 통해 관제 대상 선박의 적절한 범위 설정을 위한 방안 마련에 기여할 수 있을 것으로 기대된다.

• Smart Structures and Systems
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• 제17권3호
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• pp.363-389
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• 2016

Deficient modes that cannot be always identified from different sets of measurement data may exist in the application of operational modal analysis such as the stochastic subspace identification techniques in large-scale civil structures. Based on a recent work using the long-term ambient vibration measurements from an instrumented cable-stayed bridge under different wind excitation conditions, a benchmark problem is launched by taking the same bridge as a test bed to further intensify the exploration of mode identifiability. For systematically assessing this benchmark problem, a recently developed SSI algorithm based on an alternative stabilization diagram and a hierarchical sifting process is extended and applied in this research to investigate several sets of known and blind monitoring data. The evaluation of delicately selected cases clearly distinguishes the effect of traffic excitation on the identifiability of the targeted deficient mode from the effect of wind excitation. An additional upper limit for the vertical acceleration amplitude at deck, mainly induced by the passing traffic, is subsequently suggested to supplement the previously determined lower limit for the wind speed. Careful inspection on the shape vector of the deficient mode under different excitation conditions leads to the postulation that this mode is actually induced by the motion of the central tower. The analysis incorporating the tower measurements solidly verifies this postulation by yielding the prevailing components at the tower locations in the extended mode shape vector. Moreover, it is also confirmed that this mode can be stably identified under all the circumstances with the addition of tower measurements. An important lesson learned from this discovery is that the problem of mode identifiability usually comes from the lack of proper measurements at the right locations.

• Smart Structures and Systems
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• 제19권6호
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• pp.653-663
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• 2017

The modal parameters of the deck of Runyang Suspension Bridge (RSB) as well as their relationships with wind and temperature are studied based on the data recorded by its Structural Health Monitoring System (SHMS). Firstly, frequency analysis on the vertical responses at the two sides of the deck is carried out to distinguish the vertical and torsional vibration modes. Then, the vertical, torsional and lateral modal parameters of the deck of RSB are identified using Hilbert-Huang Transform (HHT) and validated by the identified results before RSB was opened to traffic. On the basis of this, the modal frequencies and damping ratios of RSB during the whole process of Typhoon Masta are obtained. And the correlation analysis on the modal parameters and wind environmental factors is then conducted. Results show that the HHT can achieve an accurate modal identification of RSB and the damping ratios show an obvious decay trend as the frequencies increase. Besides, compared to frequencies, the damping ratios are more sensitive to the environmental factors, in particular, the wind speed. Further study on configuring the variation law of modal parameters related with environmental factors should be continued.