• Journal of Multimedia Information System
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• 제9권2호
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• pp.103-112
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• 2022

Background: A presentation attack places the printed image or displayed video at the front of the sensor to deceive the biometric recognition system. Usually, presentation attackers steal a genuine user's biometric image and use it for presentation attack. In recent years, reconstruction attack and adversarial attack can generate high-quality fake images, and have high attack success rates. However, their attack rates degrade remarkably after image shooting. Methods: In order to comprehensively analyze the threat of presentation attack to palmprint recognition system, this paper makes six palmprint presentation attack datasets. The datasets were tested on texture coding-based recognition methods and deep learning-based recognition methods. Results and conclusion: The experimental results show that the presentation attack caused by the leakage of the original image has a high success rate and a great threat; while the success rates of reconstruction attack and adversarial attack decrease significantly.

• International Journal of Computer Science & Network Security
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• 제21권12spc호
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• pp.415-426
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• 2021

The implementation of iris biometrics on smartphone devices has recently become an emerging research topic. As the use of iris biometrics on smartphone devices becomes more widely adopted, it is to be expected that there will be similar efforts in the research community to beat the biometric by exploring new spoofing methods and this will drive a corresponding requirement for new liveness detection methods. In this paper we addresses the problem of presentation attacks (Spoofing) against the Iris Recognition System on mobile devices and propose novel Presentation Attack Detection (PAD) method which suitable for mobile environment.

• Journal of information and communication convergence engineering
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• 제18권2호
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• pp.132-146
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• 2020

Biometric technologies have become widely available in many different fields. However, biometric technologies using existing physical features such as fingerprints, facial features, irises, and veins must consider forgery and alterations targeting them through fraudulent physical characteristics such as fake fingerprints. Thus, a trend toward next-generation biometric technologies using behavioral biometrics of a living person, such as bio-signals and walking characteristics, has emerged. Accordingly, in this study, we developed a bio-signal authentication algorithm using electrocardiogram (ECG) signals, which are the most uniquely identifiable form of bio-signal available. When using ECG signals with our system, the personal identification and authentication accuracy are approximately 90% during a state of rest. When using fingerprints alone, the equal error rate (EER) is 0.243%; however, when fusing the scores of both the ECG signal and fingerprints, the EER decreases to 0.113% on average. In addition, as a function of detecting a presentation attack on a mobile phone, a method for rejecting a transaction when a fake fingerprint is applied was successfully implemented.

• 성인간호학회지
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• 제19권2호
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• pp.167-177
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• 2007

Purpose: This cross-sectional survey research was undertaken to identify the factors influencing time from onset to hospital arrival of stroke patients and to provide basic information for the development of intervention programs for stroke patients. Methods: The data were collected using a convenient sampling method from three hospitals in Inchon. The subjects were 78 patients who were diagnosed as stroke by doctor and they voluntarily participated in the study. Results: On the average, subjects arrived at the hospitals by 16.72 hours after the onset of stroke events with the range from 0.17 hours to 72 hours. Thirty-four(43.6%) subjects arrived within 3 hours which can maximize treatment effects. There was significant difference in hospital presentation time according to the level of knowledge(${\chi}^2=18.629$, p=.0003). A negative correlation was found between the hospital presentation time and self-efficacy (r= -.320, p=.004). Stepwise multiple regression analysis revealed that the most powerful predictor was self-efficacy. Self-efficacy, the level of knowledge and physical symptoms were significant factors and accounted for 21.7% of the variance of hospital presentation time in stroke patients. Conclusion: According to the results, self-efficacy is a useful concept for reducing the hospital presentation time from onset of attack in stroke patients. Therefore, nurses should consider educational programs which include not only a knowledge of stroke and recurrence prevention but also the concept of self-efficacy.

• 대한한방내과학회지
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• 제39권2호
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• pp.154-158
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• 2018

Introduction: This case report assessed the effects of Korean medicine treatments on a chronic migraine patient who did not respond to triptan. Case Presentation: The patient received Korean medicine treatments, such as acupuncture, moxibustion, cupping, and herbal medication, during a hospitalization period. The effects of treatments were assessed with the Numerical Rating Scale (NRS) and migraine attack frequency. The intensity and attack frequency of migraines were significantly reduced after the complete treatment. Conclusions: For migraines, Korean medicine such as acupuncture and herbal medication could be an alternative to conventional therapy.

• 대한한의학원전학회지
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• 제22권4호
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• pp.39-42
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• 2009

Jeongji(情志) in Chinese medicine refers to a series of psychological activity which is expressed as hui(喜), no(怒), wu(優), sa(思), bi(悲), gong(恐), gyeong(驚), together with emotion, sentiment, and cognition, which are manifested as responses of the human body to environmental changes both inside and outside. Sa(思) is a major cognitive activity, and the other six emotions are main emotional activities. The emphasis on the interrelationship between cognition, sentiment, and emotional activity is a unique characteristic of the Jeongji(情志) concept in China. Jeongji[Mental] disorder refers to a series of diseases that has a close link between the attack, clinical presentation and emotional stimulation. The attack is deeply affected by emotional stimulation, with which physical symptoms are either present or absent. However, emotional changes are clear most of the time, their effect on disease development noticeable as well. To sum up, Jeongji[Mental] disorder is related to a wide range of medical problems in fields such as internal, surgical, gynecology, pediatrics, and various psychiatric disorders, not to mention contemporary psychological disorders, neurosis, and all kinds of mental illnesses of today. Moreover, the mental and physical disorders of today all share a common pathogenesis, clinical manifestation and treatment discipline. All the more reason for deeper professional research.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.771-774
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• 2002

Highly sweep leading edge extensions(LEX) applied to delta wings have greatly improved the subsonic maneuverability of contemporary fighters. In this study, systematic approach by PIV experimental method within a circulating water channel was adopted to study the fundamental characteristics of induced vortex generation, development and its breakdown appearing on a delta wing model with or without LEX in terms of four angles of attack($15^{\circ},\;20^{\circ},\;25^{\circ},\;30^{\circ}$) and six measuring sections of chord length($30{\%},\;40{\%},\;50{\%},\;60{\%},\;70{\%},\;80{\%}$). Sideslip effect in case of the LEX was also studied for two sideslip(yaw) angles($5^{\circ},\;10^{\circ}$) at one angle of attack(20). Distribution of time-averaged velocity vectors and vorticity over the delta wing model were compared along the chord length direction. Quantitative comparison of the maximum vorticity featuring the induced pressure distribution were also conducted to clarify the significance of the LEX existence. Animation presentation in velocity distribution was also implemented to reveal the effect of LEX with wing vortex interaction.

• 한국컴퓨터정보학회지
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• 제15권1호
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• pp.53-64
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• 2007

본 논문에서는 최근의 해킹사고에서 침입자는 피해시스템에서 자신의 IP주소 노출을 피하기 위하여 피해 시스템을 직접 공격하지 않고 Stepping stone(경유지)을 이용하여 우회 공격을 수행한다. 본 논문에서는 로그기반에서는 네트워크 감사 정책을 이용하고, TCP 기반에서는 CIS, AIAA 기법과 네트워크 기반에서는 Thumbprints Algorithm, Timing based Algorithm, TCP Sequence number를 이용한 알고리즘, Sleep Watermark Tracking 기법을 이용하여 역추적 시스템을 제시하였으며, 현 인터넷 망의 구성의 물리적 또는 논리적 복잡성이 크다는 단점을 보완하기 위해, 날로 발전하고 빠른 기술 개발 속도를 갖는 침입 기술에 대응하기위해 하나의 시스템에 하나의 모듈이 아닌 기존의 알고리즘을 이용해 효과적인 역추적 시스템을 제시 하려 한다.

• 한국간담췌외과학회지
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• 제27권3호
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• pp.271-276
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• 2023

Backgrounds/Aims: Laparoscopic cholecystectomy within one week of acute cholecystitis is considered safe and advantageous. Surgery beyond first week is reserved for non-resolving attack or complications. To compare clinical outcomes of patients undergoing laparoscopic cholecystectomy in the first week and between two to six weeks of an attack of acute cholecystitis. Methods: In an analysis of a prospectively maintained database, all patients who underwent laparoscopic cholecystectomy for acute cholecystitis were divided into two groups: group A, operated within one week; and group B, operated between two to six weeks of an attack. Main variables studied were mean operative time, conversion to open cholecystectomy, morbidity profile, and duration of hospital stay. Results: A total of 116 patients (74 in group A and 42 in group B) were included. Mean interval between onset of symptoms & surgery was five days (range, 1-7 days) in group A and 12 days (range, 8-20 days) in group B. Operative time and incidence of subtotal cholecystectomy were higher in group B (statistically not significant). Mean postoperative stay was 2 days in group A and 3 days in group B. Laparoscopy was converted to open cholecystectomy in two patients in each group. There was no incidence of biliary injury. One patient in group B died during the postoperative period due to continued sepsis and multiorgan failure. Conclusions: In tertiary care setting, with adequate surgical expertise, laparoscopic cholecystectomy can be safely performed in patients with acute cholecystitis irrespective of the time of presentation.

• 영어어문교육
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• 제3호
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• pp.185-201
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• 1997

This study explores perspectives on responding to EFL students' compositions at the semantic level. In the last three decades, there has been a shift from product-oriented approach to process-oriented one to teaching writing. The shift has led to the criticism of the traditional view on teacher response. The traditional view has been under attack for its overemphasis upon form and ineffectiveness on improving student writing skill. It is also noted that research into students' reactions to the traditional teacher response has been inconclusive. The process-oriented approach, on the other hand, draws its attention to meaning and the logical development of thought as well as linguistic matters. In this context, the present study discusses what EFL teachers need to take into account in providing the semantic-level feedback on students' compositions. Firstly, teacher response to student writing is on-going; teacher feedback involves teacher intervention in the drafting process, the revision process, and the presentation of product. Secondly, in the writing conferences, the teacher provides students an opportunity to talk about writing, assistance and advice on the content/meaning of the written text, helping them expand and clarify thinking about audience(reader) and purpose.