• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.12
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• pp.1685-1689
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• 2018

In this research, 51% attack or majority attack is becoming an important security issue for proof of work based blockchains. Due to decentralized nature of blockchains, any attacks that shutdowns the network or which take control over the network is hard to prevent and assess. In this paper, different types of majority attack are summarized and the motivations behind the attacks are explained. To show the feasibility of the majority attack, we build an example mining machines that can take control over two of the public blockchains, Vertcoin and Monero.

• Journal of Chest Surgery
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• v.8 no.2
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• pp.125-134
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• 1975

The record of 137 patients with spontaneous pneumothorax seen at Busan National University Hospital during past 3years were reviewed to study the possible pathogenesis and its effective management. and the results obtained as follows; 1] The incidence of the "spontaneous" pneumothorax which developed without underlying pathology was 13-1%. The majority of those cases was considered as the result of rupture of subpleural blebs. 2] The incidence of secondary pneumothorax which developed with underlying pathology was 50.0%, in which 42.3% was combined with pulmonary tuberculosis and 8, 0% was combined with pulmonary infection. The traumatic pneumothorax was developed in 36-5% of total series. 3] In age distribution, there was pronounced difference between spontaneous and secondary pneumothorax. The majority of spontaneous pneumothorax cases was 20-30 decade and tall and tall and thin in body structure. In secondary pneumothorax, however, the incidence was relatively high in age group more than 50 years old. 4] The incidence of pneumothorax combined with pulmonary tuberculosis was particularly high in our country, and the cause of pneumothorax was seemed due to the rupture of subpleural caseous foci in some cases, but the majority was seen due to the rupture of emphysematous blebs which were formed with a pathological process of chronic tuberculosis. 5]Closed [tube] thoracotomy was the main therapeutic approach of choice in the great majority ,of pneumothorax in our series with the relapse rate of 19.6%. However, open thoracotomy and adequate surgical procedures should be undertaken in patients with continuous air leakage over 7 days and recurrent attack of pneumothorax.

• Journal of Korean Neurosurgical Society
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• v.38 no.6
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• pp.425-430
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• 2005

Objective : Recently, the survival rate and prognosis of spontaneous intracerebral hemorrhage[S-ICH] has improved, and their enhanced survival has become associated with a consequent rise in the recurrence of S-ICH. The aim of this study is to improve the prevention of recurrent S-ICH. Methods : Between January 1999 and March 2004, we experienced 48 cases of recurrence. We classified the patients into the two groups; a double ICH group and a triple ICH group. We investigated their brain CTs, MRIs, cerebral angiographies, and medical records, retrospectively. Results : Majority of patients had the intervals at least 12 months, and most of patients underwent conservative treatment. The most common hemorrhage pattern of recurrence was ganglionic-ganglionic [basal ganglia - basal ganglia], and the second attack was contralateral side of the first attack in a large percentage of all patients. Prognosis of patients was worsened in recurrent attack. Nearly all patients had medical history of hypertension, and most patients have taken antihypertensive medication at the arrival of emergency room. Conclusion : In treating hypertension for S-ICH patients, we stress that blood pressure must be thoroughly controlled over a long period of time.

• Journal of Korean Physical Therapy Science
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• v.3 no.3
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• pp.57-64
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• 1996

The purpose of this study is to investigate risk factor found in the patients with stroke in physical therapy. A questionnaire survey was carried out for 130 the patients, who had comparatively alert mentality, hospitalized in kyung hee oriental medical hospital with stroke from January, 1st to May 31st, 1996. Major findings of this stuty were as follows. 1. The stroke patients 67(51.5%)were males and 63(48.5%) femals. The age groups of 50 to 69 years accounted for 67.6% of the total stroke patients are the highest. The job groups of commerce and business of patients 58.5%. The living groups of major citys of the revealed the highest incidence(40.8%). 2. There were 40 patients (30.8 %) who had hemorrhage related condions as the direct cause of their stroke, and 90 patients (69.2 %) who had cerebral infarction with no hemorrhaging as the cause. of the disease that the patients suffered from before their stroke, blood pressure related problems were most numberous 76 patients(58.5%) had such problems. 3. A month before their attack of stroke, were asked what thay thought could become the causes of their strokes. The most frequently mentioned answers were fatigue, drinking too much, and smoking, as chosen by 45 patients(34.6 %). 4. In regarding the relation between stress and stroke, (37.7%), of the surveyed belonged to the most numerous group had of people who said they were not under stress. Yet this group had a large number of parents. And 22.3 % of the surveyed named conflicts among parents, siblings, and relatives. 5. Questions were asked to find out the relationship between complications of stroke and smoking or drinking. It was surprising to see a high rate of attack among the 55.4 % majority who answered that they did not smoke nor drink. 6. To sum up the affect of food on attack of stroke, 42.5% of the people who had a sprcey and salty diet had a higher rate of attack then the group of people with leisurely nature. 7. Looking at the family history, 40.4% of the patients said their parents also suffered the disease. This percentage is the highest. And 40.0% answered that there is no one who suffered in their family history. Judging from the percentages and family.

• Journal of Chest Surgery
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• v.24 no.5
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• pp.451-458
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• 1991

We have observed 101 cases of recurrent spontaneous pneumothorax from Sep. 1979 to Dec. 1989 at the Department of Thoracic & Cardiovascular Surgery, College of Medicine, Inje University, Pusan Paik Hospital and the result obtained as follows. 1] Age range of patients was the first decade to seventh decade. Males outnumbered females by 6.7: l. One or two episodes of recurrent attack were noted in majority cases. 2] In distribution of the lesion sites, right side was 55 cases[55.4%], left 42 cases[41.9%], and bilateral 4 cases[3.0%]. 3] In clinical manifestations, abrupt onset of dyspnea was 78 cases[77.2%], chest pain 48 cases[47.5%], cough 9 cases[8.9%] and chest discomfort 8 cases[7.9%]. 4] Of 101 cases, 48 cases were associated with pulmonary tuberculosis and other cases were associated with subpleural bullae and blebs[26 cases], emphysema[7 cases], bronchiectasis[2 cases], lung cancer[1 case], and silicosis[1 case], 5] In 88 cases[87.2%] of patients, the magnitude of collapse was above 50% in plain chest film. 6] The interval of recurrence after last attack was frequently within 1 year. 7] In the management, closed thoracostomy with underwater-sealed drainage was applied in first recurrent 53 cases but 2nd recurrence was developed in 16 cases. In 52 cases, surgical management was applied. The pleurodesis with chemical agent[tetracycline] via chest tube was applied in 2 cases. Among 51 cases subjected to the open thoracotomy, pleural abrasion was performed in 3 cases, excision of bullae & blebs in 12 cases, wedge resection in 28 cases, lobectomy in 6 cases and wedge resection combined with lobectomy in 2 cases. In one case subjected to the median sternotomy, wedge resection on both lung apex was performed. 8] Postoperative complications were developed in 8 cases but not serious.

• The Journal of the Korea Contents Association
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• v.12 no.5
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• pp.32-39
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• 2012

When you want to be given the on-line service, their homepage requires sign-up with detail personal information. This collected private information lead to mass data spill by hacking. Especially, this makes terrible social problems that the users who sign up their site are persistingly attacked and damaged by hackers using this information. As methods of the social technologic attacks are simple but based upon human psychology, it is easy that people become a victim in the majority of cases. There is a strategy blocking fishing sites by using the black list for defending these attacks. This tactic, however, has some problems that it isn't possible to handle new fishing sites having a short life-cycle. In this paper, we suggest two solutions to minimize data spill. One marks existing sites with the sign of a reliability measured by a comparison between black list and the white list; therefore, the user check the authenticity about the homepage. The other shut off previously the leaking of private information by sensing a entry of personal information into new sites.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.4
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• pp.867-875
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• 2014

Rapid development of internet service is enabling internet banking services in anywhere and anytime. However, service access through internet can be exposed to adversary easily. To prevent, current service providers execute authentication process with user's identification and password. However, majority of users use short and simple password and do not periodically change their password. As a result of this, user's password could be exposed to attacker's brute force attack. In this paper, we presented enhanced password system which guarantee higher security even though users do not change their current password. The method uses additional secret information to replace real password periodically without replacement of real password.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.6
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• pp.2168-2187
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• 2021

The smart grid replaces the traditional power structure with information inventiveness that contributes to a new physical structure. In such a field, malicious information injection can potentially lead to extreme results. Incorrect, FDI attacks will never be identified by typical residual techniques for false data identification. Most of the work on the detection of FDI attacks is based on the linearized power system model DC and does not detect attacks from the AC model. Also, the overwhelming majority of current FDIA recognition approaches focus on FDIA, whilst significant injection location data cannot be achieved. Building on the continuous developments in deep learning, we propose a Deep Learning based Locational Detection technique to continuously recognize the specific areas of FDIA. In the development area solver gap happiness is a False Data Detector (FDD) that incorporates a Convolutional Neural Network (CNN). The FDD is established enough to catch the fake information. As a multi-label classifier, the following CNN is utilized to evaluate the irregularity and cooccurrence dependency of power flow calculations due to the possible attacks. There are no earlier statistical assumptions in the architecture proposed, as they are "model-free." It is also "cost-accommodating" since it does not alter the current FDD framework and it is only several microseconds on a household computer during the identification procedure. We have shown that ANN-MLP, SVM-RBF, and CNN can conduct locational detection under different noise and attack circumstances through broad experience in IEEE 14, 30, 57, and 118 bus systems. Moreover, the multi-name classification method used successfully improves the precision of the present identification.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.4
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• pp.15-23
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• 2021

In most hacking attacks, hackers intrudes inside for a long period of time and attempts to communicate with the outside using a circumvent connection to achieve purpose. research in response to advanced and intelligent cyber threats has been mainly conducted with signature-based detection and blocking methods, but recently it has been extended to threat hunting methods. attacks from organized hacking groups are advanced persistent attacks over a long period of time, and bypass remote attacks account for the majority. however, even in the intrusion detection system using intelligent recognition technology, it only shows detection performance of the existing intrusion status. therefore, countermeasures against targeted bypass rwjqthrwkemote attacks still have limitations with existing detection methods and threat hunting methods. in this paper, to overcome theses limitations, we propose a model that can detect the targeted circumvent connection remote attack threat of an organized hacking group. this model designed a threat hunting process model that applied the method of verifying the origin IP of the remote circumvent connection, and verified the effectiveness by implementing the proposed method in actual defense information system environment.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.4 no.1
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• pp.89-98
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• 1991

Clinical study on the 114 facial paralysis patients, visited Won Kwang University Oriental Medical Hospital in Kwang ju from July 1990 to Jun 1991, was carried out. The results obtained are as follows. 1. Prevalence was almost same in both sexes and high in the age of 3 and 4 decades but distributed in an age group. 2. Majority of the patients were nomotensive, which meant blood pressure did not affect the incidence. 3. The incidence distributed in every occupations but high in housewife as 37 cases ($32\%$) and decreased gradually in office employee, labor worker, student and merchant in order. 4. Overwork, wind and cold, emotional stress, and numerous implicated agents were etiological factor. 5. The paralysis mostly occured in summer and winter as 40($35\%$) and 37 cases($32\%$) respectively, 18($16\%$) and 19cases($17\%$) were recorded respectively in spring and autumn. 6. The majority of patients showed only facial muscle paralysis without other complications, whose cure rate was $60\%$ (47 cases). The patients with auditory impairment or taste loss was less common and cure rate was low. 7. The number of the patients with migraine or mastoid pain was 81($71\%$), which was more than 33 patients($29\%$) with such pain. The cure rate was high in the patients without migraine than with migraine as a raito of 64 to $46\%$. 8. Most of duration from attack to admission were in a week as 86 cases($75\%$) and the patients with duration over 4 weeks 11 cases($10\%$). The cure rate of the patients in a week, was 54 cases($60\%$) and the patients over 4 weeks was none($0\%$), which meant shorter the duration was, the beter the result was. 9. Response on electro acupuncture on initiating therapy showed good in 39 cases($34\%$) the majority group, moderate in 37 cases, exellent in 29 cases and poor in 5 cases. 10. The results of treatment were as follows : asymptomatic in 58 cases($51\%$), improved n 40cases($35\%$), effective in 10 cases($9\%$) and ineffective in 6 cases($5\%$). 11. Cure rate according to the response on electro acupuncture showed $72\%$ in exellent group, $59\%$ in good group, $27\%$ in moderate groop, and $0\%$ in poor group. These show the better the response on the electro-acupuncture is, the higher the cure rate is, which will be able to indicate the prognosis of facial paralysis.