• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.392-394
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• 2014

요즘 인터넷을 통하여 많은 사이버 공격이 일어나고 있다. 이에 대응하기 위하여 우리는 네트워크 패킷을 저장할 수 있는 사이버 블랙박스 시스템을 개발하고 사이버 블랙박스 시스템에서 수집한 많은 네트워크 패킷을 분석할 수 있는 효율적인 공격 원인 분석 알고리즘을 제안한다. 공격원인 분석 알고리즘을 통하여 우리는 사이버 공격에 발생했을 때 공격의 유입점이 어디이고 어떤 경로를 통해서 공격이 이루어졌는지 알 수 있다. 그 뿐만 아니라 숨겨진 피해자 발견 알고리즘을 통하여 알려진 피해자뿐만 아니라 알려지지 않은 다른 피해자를 찾을 수 있다.

• Journal of Chest Surgery
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• v.20 no.1
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• pp.39-47
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• 1987

The records of 268 patients, who were diagnosed as spontaneous pneumothorax during the period 1975 to 1984, treated at the department of thoracic and cardiovascular surgery, Hanyang University Hospital, were reviewed retrospectively to evaluate the effect of surgical intervention on each indications. Of these,.61 patients [22.8%] were taken operation to treat the pneumothorax after closed thoracostomy. We have classified the 61 patients to evaluate the therapeutic effect on each indications. And the therapeutic effect is based on the chest tube indwelling days. The results were as follows: 1. The chest tube indwelling days of the group who were taken closed thoracostomy only was average 14.13*9.17 days [range 5-66 days], and that of the group who were finally taken the thoracotomy after closed thoracostomy was 21.85*12.30 days [range 5-55 days]. 2. The indications of thoractomy were thoracoscopic findings, recurrence and continuous air leakage. 3. The chest tube indwelling day of the group who was taken thoracotomy by thoracoscopic findings was average 11.67*6.51 day, that was relatively short compared to those of the other groups. 4. The continuous air leakage group after closed thoracostomy was subdivided into three subgroups, continuous air leakage in 1st attack, thoracoscopic findings in 1st attack, and recurrence. 5. Of these, the chest tube indwelling day of the subgroup, who was taken operation by thoracoscopic findings, was 21.33e8.26, that was relatively short compared with those of the other subgroups. We use the thoracoscope as excellent diagnostic tool to detect the operation indication in the spontaneous pneumothorax patients. And we gain the benefits to shorten the chest tube indwelling days and admission days, and also to protect the recurrence.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.4
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• pp.141-146
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• 2015

Data have been increased enormously due to the development of IT technology such as recent smart equipments, social network services and streaming services. To meet these environments the technologies that can treat mass data have received attention, and the typical one is Hadoop. Hadoop is on the basis of open source, and it has been designed to be used at general purpose computers on the basis of Linux. To initial Hadoop nearly no security was introduced, but as the number of users increased data that need security increased and there appeared new version that introduced Kerberos and Token system in 2009. But in this method there was a problem that only one secret key can be used and access permission to blocks cannot be authenticated to each user, and there were weak points that replay attack and spoofing attack were possible. Hence, to supplement these weak points and to maintain efficiency a protocol on the basis of group key, in which users are authenticated in logical group and then this is reflected to token, is proposed in this paper. The result shows that it has solved the weak points and there is no big overhead in terms of efficiency.

• Korean Journal of Biological Psychiatry
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• v.14 no.3
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• pp.194-200
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• 2007

Objectives:This study was performed to investigate the differences of the clinical feature between panic disorder with agoraphobic patients and panic disorder without agoraphobic patients. Methods:Two hundred nine patients meeting the criteria of DSM-IV panic disorder were recruited. One group was panic disorder with agoraphobia(n=78, 42 male(53.8%), mean age $37.6{\pm}9.9$ years), another was panic disorder without agoraphobia(n=131, 81 male(61.8%), mean age $40.5{\pm}10.3$ years). The numbers and frequency of panic symptoms were compared between two groups with t-test, and the logistic regression analysis were used for predicting panic disorder with agoraphobia. Results:The number of panic symptoms during panic attack was significantly higher in the group of panic disorder with agoraphobia than the group of panic disorder without agoraphobia(p<0.05).'Sweating','nausea or abdominal distress','fear of losing control of going crazy','chills or hot flushes'were more frequent in the group of panic disorder with agoraphobia(p<0.05). Among panic symptoms on logistic regression analysis,'sweating',' nausea or abdominal distress','fear of losing control or going crazy'turned out to correlate significantly with risk of development of agoraphobia in panic disorder. Conclusion:These results suggest that the frequency of some symptoms during panic attack may be a predictor of agoraphobia in patients with panic disorder.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.1
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• pp.97-101
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• 2007

The purpose of DRM is to protect the copyrights of content providers and to enable only designated users to access digital contents. From the consumers' point of view, they have a tendency to go against complex and confusing limitations. Moreover, consumers' rights of use of the content obtained legally were frequently harmed by arbitrary limitations. The concept of Authorized Domain (AD) was presented to remove such problems. However, the previous work on authorized domain has two problems. The first is that it requires a rather expensive revocation mechanism for withdraw process. The second is that the modules still can play contents which are previously obtained even though they are currently out of the authorized domain. On the contrary, our scheme presents the content from being played by modules which are out of the domain for better security. Furthermore our scheme does not need to maintain a revocation list and prevent replay attack.

• Journal of Convergence for Information Technology
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• v.12 no.3
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• pp.38-45
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• 2022

Due to the development of fintech technology, financial transactions using smart phones are being activated. The password for user authentication during financial transactions is entered through the virtual keypad displayed on the screen of the smart phone. When the password is entered, the attacker can find out the password by capturing it with a high-resolution camera or spying over the shoulder. A virtual keypad with security applied to prevent such an attack is difficult to input on a small touch-screen, and there is still a vulnerability in peeping attacks. In this paper, the entire keypad is divided into several groups and displayed on a small screen, touching the group to which the character to be input belongs, and then touching the corresponding character within the group. The proposed method selects the group to which the character to be input belongs, and displays the keypad in the group on a small screen with no more than 10 keypads, so that the size of the keypad can be enlarged more than twice compared to the existing method, and the location is randomly placed, hence location of the touch attacks can be blocked.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.11 no.1
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• pp.300-318
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• 1998

Background : The vasoreactivity of cerebral artery is currently the subject of increasing interest. Transcranial Doppler Sonography(TCD) is an accurate method of monitoring the blood flow velocities of the cerebral artery. We wished to assess the vasoreactivity between age-matched normal and cerebral infarction group. Method : We performed TCD findings in 40 normals and 20 cb-inf. subjects who arrived at hospital during 48 hours after attack. The former were devided into twenties normal group and fifties normal group. Result : 1. Fibrinogen levels showed significant changes between age-matched normal and cb-inf. group. 2. $V^{MEAN}$ of the both side Carotid Siphon during rest state increased significantly in cb-inf. group as compared with the age-matched normal group. 3. $V^{MEAN}and\;V^{MAX}$ of the both side carotid siphon during breath-hold state increased significantly in cb-inf. group as compared with the age-matched normal group. 4. Vasoreactivity of cerebral artery increased significantly in cb-inf. group as compared with the age-matched normal group. 5. $V^{MEAN}and\;V^{MAX}$ of the both side Radial artery during heat-stimuration state increased significantly in cb-inf. group as compared with the age-matched normal group. 6. Vasoreactivity of Radial artery increased significantly in cb-inf. group as compared with the age-matched normal group.

• The Journal of Information Systems
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• v.20 no.2
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• pp.81-107
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• 2011

Group features such as group cohesion and consistency on appropriation(COA), which have been constructed through social interactions, should be noted for characterizing online game, especially, clan based massively multi-players online game (MMOG). This study attempted to identify the relationship between group characteristics and users' effectiveness of MMOG considering group experience. For this purpose, a research model was suggested: group cohesion and COA are variables for explaining group features, perceived use control is a variable for individual competency of playing MMOG, and perceived winning and perceived enjoyment are dependent variables. Moreover, group experience was included as a moderating variables for two relationships, group cohesion-preceived winning and COA-perceived winning. For the validation of this research model, 100 users for Sudden Attack which is one of very well known MMOG games were surveyed by questionnaires. Before survey, they were grouped into 10 teams and were played over ten times by team for perceiving group consciousness. In result, most hypotheses were statistically supported except the relationship between group cohesion and perceived winning.

• Bulletin of the Korean Chemical Society
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• v.33 no.3
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• pp.1042-1046
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• 2012

The kinetics and mechanism of the pyridinolysis ($XC_5H_4N$) of diethyl isothiocyanophosphate are investigated in acetonitrile at $55.0^{\circ}C$. The Hammett and Bronsted plots for substituent X variations in the nucleophiles exhibit the two discrete slopes with a break region between X = 3-Ac and 4-Ac. These are interpreted to indicate a mechanistic change at the break region from a concerted to a stepwise mechanism with rate-limiting expulsion of the isothiocyanate leaving group from a trigonal bipyramidal pentacoordinated intermediate. The relatively large ${\beta}_x$ values with more basic and less basic pyridines imply much greater fraction of frontside nucleophilic attack TSf than that of backside attack TSb.

• Bulletin of the Korean Chemical Society
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• v.35 no.9
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• pp.2797-2802
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• 2014

Nucleophilic substitution reactions of Y-aryl methyl (8) and Y-aryl propyl (10) chlorothiophosphates with substituted anilines and deuterated anilines are investigated kinetically in acetonitrile at $55.0^{\circ}C$. A concerted mechanism is proposed for 8 based on the negative ${\rho}_{XY}$ (= -0.23) value, while a stepwise mechanism with a rate-limiting leaving group departure from the intermediate is proposed for 10 based on the positive ${\rho}_{XY}$ (= +0.68) value. The deuterium kinetic isotope effects (DKIEs; $k_H/k_D$) are 0.89-1.28 and 0.62-1.20 with 8 and 10, respectively. Primary normal and secondary inverse DKIEs are rationalized by a frontside attack involving hydrogen bonded, four-center-type transition state and backside attack involving in-line-type transition state, respectively.