• 한국안전학회지
• /
• 제17권1호
• /
• pp.39-44
• /
• 2002

This paper shows error in the polarization direction on ultrasonic transducers how sensitive the shear ultrasonic waves are to a little misoriented plies according to the angle variation of shear ultrasonic waves $0{\circ},\;45{\circ}$ and $90{\circ}$. Also, it is shown that shear waves, particularly the transmission mode with the transmitter and receiver perpendicular to cach other, have high sensitivity for detecting anomalies in fiber orientation and ply layup sequence that may occur in the manufacturing of composite laminates. Experimental results are agreed with a modeling solutions which was based on decomposition of shear wave polarization vector as it propagates through the composite laminates. This wave appeared considerably to be sensitive to CFRP composites to thickness direction along in-plane fibers.

• 한국멀티미디어학회논문지
• /
• 제10권12호
• /
• pp.1726-1732
• /
• 2007

The rapid proliferation of wireless networks and mobile computing applications has changed the landscape of network security. Anomaly detection is a pattern recognition task whose goal is to report the occurrence of abnormal or unknown behavior in a given system being monitored. This paper presents an efficient rough set based anomaly detection method that can effectively identify a group of especially harmful internal attackers - masqueraders in cellular mobile networks. Our scheme uses the trace data of wireless application layer by a user as feature value. Based on this, the used pattern of a mobile's user can be captured by rough sets, and the abnormal behavior of the mobile can be also detected effectively by applying a roughness membership function with the age of the user profile. The performance of the proposed scheme is evaluated by using a simulation. Simulation results demonstrate that the anomalies are well detected by the proposed scheme that considers the age of user profiles.

• 센서학회지
• /
• 제15권5호
• /
• pp.328-333
• /
• 2006

Magnetic Flux Leakage (MFL) methods are widely employed for the nondestructive evaluation (NDE) of gas pipelines. In the application of MFL pipeline inspection technology, corrosion anomalies are detected and identified via their leakage filed due to changes in wall thickness. The gas industry is keenly interested in automating the interpretation process, because a large amount of data to be analyzed is generated for in-line inspection. This paper presents a novel approach to the tasks of data segmentation, feature extraction and depth estimation from gas pipelines. Also, we will show that the proposed method successfully identifying artificial defects.

• Journal of the Korean Data and Information Science Society
• /
• 제18권2호
• /
• pp.315-326
• /
• 2007

The rapid proliferation of wireless networks and mobile computing applications has changed the landscape of network security. Anomaly detection is a pattern recognition task whose goal is to report the occurrence of abnormal or unknown behavior in a given system being monitored. This paper presents a dynamic anomaly detection scheme that can effectively identify a group of especially harmful internal masqueraders in cellular mobile networks. Our scheme uses the trace data of wireless application layer by a user as feature value. Based on the feature values, the use pattern of a mobile's user can be captured by rough sets, and the abnormal behavior of the mobile can be also detected effectively by applying a roughness membership function with both the age of the user profile and weighted feature values. The performance of our scheme is evaluated by a simulation. Simulation results demonstrate that the anomalies are well detected by the proposed dynamic scheme that considers the age of user profiles.

• 비파괴검사학회지
• /
• 제33권2호
• /
• pp.232-240
• /
• 2013

This paper presents recent advances in damage visualization algorithms of laser generated ultrasonic propagation imaging(UPI) system. An effective damage evaluation method is required to extract correct information from raw data to properly characterize anomalies present in structure. A temporal-reference free imaging system provides easy and rapid defect inspection capability with less computational complexity. In this paper a number of methods such as ultrasonic wave propagation imaging(UWPI), anomalous wave propagation imaging(AWPI), ultrasonic spectral imaging(USI), wavelet ultrasonic propagation imaging(WUPI), variable time window amplitude mapping(VTWAM), time point adjustment(TPA), time of flight and amplitude mapping(ToF&Amp) and ultrasonic wavenumber imaging(UWI) are discussed with instances of successful implementation on various structures.

• Journal of Chest Surgery
• /
• 제25권8호
• /
• pp.832-836
• /
• 1992

A 25-month-old patient with complete atrioventricular septal defect and Tetralogy of Fallot underwent repair of both anomalies. The diagnosis was established preoperatively by 2D-echocardiography, cardiac catheterization and cardioangiogram, Repair was accomplished using cardiopulmonary bypass and profound hypothermia to 18C, Closing of the atrioventricular septal defect was achieved with the use of two Dacron patchs by an atrial approach alone. Infundibulectomy and outflow tract reconstruction with the transannular pericadial patch containing a monocusp were performed. Upon the postoperative evaluation by 2D-echocardiography, mitral regurgitation was absent, but a tiny dehiscence of ventricular patch and minimal tricuspid regurgitation were noticed.

• Journal of Chest Surgery
• /
• 제32권12호
• /
• pp.1111-1114
• /
• 1999

Cor triatriatum is a rare congenital heart disease that is often lethal in children if not correctly identified and properly managed, Characteristically an anomalous membrane divides the left atrium into two chambers one located posterosuperiorly which is connected to the common pulmonary venous trunk and the other anteroinferiorly which is connected to the left atrial appendage and the mitral valve. Eight patients with Cor triatriatum were been seen at our hospital from 1984 to 1999. The clinical presentation diagnostic evaluation and surgical results are outlined in this retrospective review. Resection of the obstructing anomalous atrial membrane was performed using a hypothermic cardiopulmonary bypass in all cases. Right atriotomy was performed in all patients and left atriotomy was performed in a patient who had poor preoperative general conditions and serious cardiac defects(TAPVR & hypoplastic left ventricle) died of low cardiac output during the immediate postoperative period. The postoperative course has been excellent in the remaining. Cor triatriatum is amenable to surgical repair with excellent results when diagnosed early and in those who are not complicated by other complex cardiac anomalies.

• Journal of Chest Surgery
• /
• 제27권6호
• /
• pp.472-476
• /
• 1994

The incidence of single coronary artery is extremely rare in a review of congenital anomalies of the coronary arteries. This 27-year-old male patient was referred for the evaluation of cardiac condition showing exertional dyspnea[NYHA class II-III] and chest discomfort for about 1 year. A complete catheterization study including angiogram disclosed large single coronary artery arising from left aortic sinus [Ogden classification L-4] associated with bicuspid aortic valvular stenosis and low grade supravalvular aortic stenosis. Calcified stenotic aortic valve was fully removed with caution and the 19mm St. Jude Medical valve was then implanted in the small nortic annulus. The patient had an uneventful recovery and was discharged on 13th postoperative day.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2008년도 추계종합학술대회 B
• /
• pp.261-264
• /
• 2008

IPv6 has been proposed and deployed to cater the shortage of IPv4 addresses. It is expected to foresee mobile phones, pocket PCs, home devices and any other kind of network capable devices to be connected to the Internet with the introduction and deployment of IPv6. This scenario will bring in more challenges to the existing network infrastructure especially in the network security area. Firewalls are the simplest and the most basic form of protection to ensure network security. Nowadays, firewalls' usage has been extended from not only to protect the whole network but also appear as software firewalls to protect each network devices. IPv6 and IPv4 are not interoperable as there are separate networking stacks for each protocol. Therefore, the existing states of the art in firewalling need to be reengineered. In our context here, we pay attention only to the IPv6 firewalls configuration anomalies without considering other factors. Pre-evaluation of security risk is important in any organization especially a large scale network deployment where an add on rules to the firewall may affect the up and running network. We proposed a new probabilistic based model to evaluate the security risks based on examining the existing firewall rules. Hence, the network administrators can pre-evaluate the possible risk incurred in their current network security implementation in the IPv6 network. The outcome from our proposed pre-evaluation model will be the possibilities in percentage that the IPv6 firewall is configured wrongly or insecurely where known attacks such as DoS attack, Probation attack, Renumbering attack and etc can be launched easily. Besides that, we suggest and recommend few important rules set that should be included in configuring IPv6 firewall rules.

• 대한장애인치과학회지
• /
• 제6권2호
• /
• pp.94-98
• /
• 2010

저자는 Axenfeld-Rieger 증후군을 가지는 5세 8개월 연환에 대한 구강 및 두개 안면에 대한 임상적, 방사선학적 관찰을 통해 다음과 같은 지견을 얻었다. 1. 본 증례의 환아는 Axenfeld-Rieger 증후군의 전형적인 안과적, 구강적, 전신적 특징인 녹내장, 동공이상, 제탈장, 지연된 골령, 다수 치아 및 치배 결손, 상악 저성장 등을 보였다. 2. 이에 대한 주기적인 관찰과 적절한 시기의 치료개입이 중요하다. 3. 치과의사에 의한 조기진단이 녹내장 등에 의한 시력상실을 방지하기 위해 중요하다.