Private Key Recovery on Bitcoin with Duplicated Signatures

( Ju-seong Ko ),( Jin Kwak ) 한국인터넷정보학회 2020 KSII Transactions on Internet and Information Syst Vol.14 No.3

In the modern financial sector, interest in providing financial services that employ blockchain technology has increased. Blockchain technology is efficient and can operate without a trusted party to store all transaction information; additionally, it provides transparency and prevents the tampering of transaction information. However, new security threats can occur because blockchain technology shares all the transaction information. Furthermore, studies have reported that the private keys of users who use the same signature value two or more times can be recovered. Because private keys of blockchain identify users, private key leaks can result in attackers stealing the ownership rights to users’ property. Therefore, as more financial services use blockchain technology, actions to counteract the threat of private key recovery must be continually investigated. Private key recovery studies are presented here. Based on these studies, duplicated signatures generated by blockchain users are defined. Additionally, scenarios that generate and use duplicated signatures are applied in an actual bitcoin environment to demonstrate that actual bitcoin users’ private keys can be recovered.

점막하 위암에서 림프절 전이에 영향을 미치는 인자

고성주(Seong Ju Ko),서재환(Jae Hwan Suh),박흥규(Heung Kyu Park),이훈규(Hoon Gyu Lee),조승연(Seung Yeon Cho),이운기(Woon Gi Lee),이정남(Jeong Nam Lee),이영돈(Young Don Lee),조현이(Hyun Yee Cho) 대한외과학회 2002 Annals of Surgical Treatment and Research(ASRT) Vol.62 No.2

조영제와 생리식염수 혼합물을 이용한 표면선량 감소에 관한연구

고주성(Ju seong Ko),임상묵(Sang muk Yim),강화원(Hwawon Gang),김대현(Dae hyeon Kim) 대한전산화단층기술학회 2015 대한CT영상기술학회지 Vol.17 No.2

목적 : 조영제와 생리식염수를 섞어서 조영제 농도를 달리해 차폐물을 제작하여 조영제 농도에 따른 표면선량 차폐효과에 대해 알아보고자 하였다. 대상 및 방법 : CT장비는 SOMATOM Definition(Siemens, Germany)를 사용하였고, 선량의 측정을 위해 Atom Phantom(CIRS)과 형광유리소자(GD-352M:Chiyoda Technol Japan)을 사용하으며, 선량판독기(FDG-1000;AGC, Techno Glass, Shizuoka, Japan)를 이용하였다. 화질평가를 위해 AAPM Phanrom(Model 76-410, Nuclear Associates LTD)을 사용하였다. 기존의 차폐물질인 BISMUTH(F&L Medical Products co, 0.060mmpb equivalent, USA)와조영제와 생리식염수를 혼합하여 제작한 조영제 200 cc+생리식염수 200 cc, 조영제 100 cc+생리식염수 300cc, 조영제 50 cc+ 생리식염수 350cc, 조영제 25 cc+생리식염수 375 cc, 조영제 10cc+생리식염수 390 cc을 비교하였.다 조영제 혼합차폐물을 Atom 팬텀의 흉부위에올려놓고 형광유리선랑계를 양측 유두부 위치와 폐야에 위치시켜서 각각 선량을 측정하였으며, 비교를 위해 BISMUTH 사용했을 때와 차폐체 없을때 와의 선량을 비교 측정하였다. 피사체와차폐물과의 거리를 0 cm, 0.7 cm, 1.4 cm, 2.1 cm으로 변화시켜 거리에 따른 선량변화를 측정하였고 Image Quality를 측정하기 위해 AAPM Phantom을 이용하여 위 실험과 같은 방법으로 노이즈와 균일도를 측정하였다. 결과 : bone plus algorithm을 대조군으로 환자데이터를 분석하였다. soft tissue에서 SD값이 ultra algorithm은 FBP와 ASIR30% 모두 bone plus algorithm과 차이가 없었다. edge algorithm은 SD값이 FBP와 ASIR30% 각각 28.78%, 34.63% 증가했다. bone어|서 SD값이 ultra algorithm은 FBP와 ASIR30% 가각 18.88%, 19.78% 증가했고, edge algorithm은 FBP와 ASIR30% 각각 10%, 9.1% 감소했다. 공간분해능과 선예도 측정결과 bone plus, edge, ultra algorithm의 MTF50% 값은 FBP에서 각각 4.28, 0.62, 5.64였고, ASIR30%는 4.39, -3.77, 6.17이었다. MTF10%값은 FBP에서 6.50, 5.85, 10.01 이었고, ASIR30%는 6.91, 5.74, 21.98이었다. 측정결과 ultra algorithm의 공간분해능과 선예도가 가장 좋았다. 결론 : Ultra algorithm은 기존의 bone plus, edge algorithm과 비교했을 때 저주파영역의 노이즈 증가없이 고주파영역만 강조하면서 영상의 화질 또한 우수하다는 것을 알 수 있었다. 임상 Temporal bone CT검사에서 ultra algorithm은 bone plus algorithm과 비교하여 적절히 사용한다면 매우 유용할 것이라 사료된다. Purpose : The purpose of this study lies in examining the screening effect of surface absorbed dose based on concentration of contrast media by manufacturing a screen with different contrast media concentration by mixing contrast media and physiological saline solution. Materials & Methods : SOMATOM Definition (Siemens, Germany) was used for CT device and Atom Phantom (CIRS) and fluorescent glass element (GD-352M;Chiyoda Technol Japan) were used for measurement of dose. Also, dosimeter (FDG-1000;AGC, Techno Glass, Shizuoka, Japan) was used to measure absorbed dose and AAPM Phantom(Model 76-410, Nuclear Associates LTD) was used for image quality assessment. The comparison was conducted with mixture of previous screen BISMUTH (F&L Medical Products co, 0.060mmpb equivalent, USA) and contrast media 200 cc + normal saline solution 200 cc, contrast media 100 cc + normal saline solution 300cc. contrast media 50 cc + normal saline solution 350 cc. contrast media 25 cc + normal saline solution 375 cc, and contrast media 10 cc + normal saline solution 390 cc manufactured with mixture of contrast media and normal saline solution. The absorbed dose was measured by fluorescent glass dosimeter after placing contrast media mixed screen to the thorax of atom phantom and fluorescent glass dosimeter to the location of both nipples and lung field. Comparative measurement was conducted in order to compare the dose with the use of BISMUTH and without use of screen. The changes in doses accordingly with distance were measured by changing distance between the subject and screen into 0cm. 0.7cm, 1.4cm, and 2.1 cm and noise and uniformity were measured with same method as above experiment using AAPM Phantom for the measurement of image quality. Result : Although reduction effect of surface absorbed dose was greatest with the use of contrast media 200 cc + normal saline solution 200 cc presenting 4.2 mGy, it has exceeded allowable range when measuring the uniformity. Although there was two-fold increase in surface absorbed dose for screen manufactured with made of contrast media 25cc + normal saline solution 375 cc in comparison with contrast media 200 cc+ normal saline solution 200 cc, the uniformity was measured within allowable range presenting the surface absorbed dose of 8.1 mGy. Also, there was surface absorbed dose reduction of 27% compared to surface absorbed dose 11.0 mGy scanned without screen. There were little changes in surface absorbed doses based on changes in distance between contrast media mixed screen and subject. In regards to noise assessment, it was measured to be the lowest presenting 11.7 without screen and the highest presenting 29.3 with the use of contrast media 200 cc+ normal saline solution 200 cc. With the screen, it was measured to be the lowest presenting 14.7 for contrast media 10 cc + normal saline solution 390 cc. Conclusion : Surface absorbed dose reduction effect of 27% could be acquired compared to previous screen BISMUTH and uniform CT number could be obtained with the use of contrast media mixed screen 25 cc + 375 cc. It is believed that contrast media mixed screen wⅢ be of great assistance to surface absorbed dose reduction in case there is no previous screen.

광주 외국인 노동자 건강센터의 치과진료 실태

고석주 ( Seok Ju Ko ),홍석진 ( Suk Jin Hong ),윤혜정 ( Hye Jeong Youn ),정성숙 ( Seong Soog Jeong ),정은주 ( Eun Ju Jung ),최충호 ( Choong Ho Choi ) 대한예방치과·구강보건학회 2010 大韓口腔保健學會誌 Vol.34 No.1

Objectives. To evaluate the results of a dental service program operated for foreign workers by a dental team in Gwangju. Methods. Data was collected and analyzed from the dental charts of 312 foreign workers treated at a single dental center from September, 2005 to August, 2007. The general condition of the dental service program was also surveyed. Chi-square test was used for comparison among groups. Results. Most patients were East Asian men 20~39-years-of-age, likely due to the location of the health center in an industrial area and its treatment-only purpose. They received oral medicine treatment (50 patients, 53 cases), periodontal treatment (130 patients, 163 cases), operative and root canal treatment (228 patients, 422 cases), surgical treatment (87 patients, 99 cases), and prosthetic treatment (16 patients, 16 cases). No differences were evident in patients receiving oral medicine and surgical treatments in terms of gender, nationality, and age (p>0.05). Significant difference were evident in patients receiving. operative and root canal treatments in terms of amalgam filling (nationality), zinc oxide eugenol filling (nationality and age) and glass ionomer filling (gender and age)(p<0.05). Significant differences were evident in patients receiving periodontal treatment in terms of gender and nationality (p<0.05). Conclusions. In order to improve the dental service program for foreign workers, practitioners should be encouraged to establish relationships with dental association, have access to interpreters to ease language-related difficulties, focus on preventive treatments through available oral health education resources, and use prosthetic treatments. In addition, systemic government and private sector financial and infrastructure support would be fruitful to enable maximum provision of services and hiring of more practitioners.

[PF-0011] Identification of freesia infecting viruses based on next-generation sequencing technique in Korea

Jun-Sung Shin(Jun-Sung Shin ),Jung-Heon Han(Jung-Heon Han ),Seong-Kyeong Lee(Seong-Kyeong Lee ),Yu-Ju Shin(Yu-Ju Shin ),Myunghoon Ko(Myunghoon Ko ),Hoseong Choi(Hoseong Choi ) 한국육종학회 2022 한국육종학회 공동학술발표집 Vol.2022 No.-

Discovery of a Novel Highly Selective Histamine H4 Receptor Antagonist for the Treatment of Atopic Dermatitis

Ko, Kwangseok,Kim, Hye-Jung,Ho, Pil-Su,Lee, Soon Ok,Lee, Ji-Eun,Min, Cho-Rong,Kim, Yu Chul,Yoon, Ju-Han,Park, Eun-Jung,Kwon, Young-Jin,Yun, Jee-Hun,Yoon, Dong-Oh,Kim, Jung-Sook,Park, Woul-Seong,Oh, Se American Chemical Society 2018 Journal of medicinal chemistry Vol.61 No.7

<P>The histamine H4 receptor (H4R), a member of the G-protein coupled receptor family, has been considered as a potential therapeutic target for treating atopic dermatitis (AD). A large number of H4R antagonists have been disclosed, but no efficient agents controlling both pruritus and inflammation in AD have been developed yet. Here, we have discovered a novel class of orally available H4R antagonists showing strong anti-itching and anti-inflammation activity as well as excellent selectivity against off-targets. A pharmacophore-based virtual screening system constructed in-house successfully identified initial hit compound <B>9</B>, and the subsequent homology model-guided optimization efficiently led us to discover pyrido[2,3-<I>e</I>]tetrazolo[1,5-<I>a</I>]pyrazine analogue <B>48</B> as a novel chemotype of a potent and highly selective H4R antagonist. Importantly, orally administered compound <B>48</B> exhibits remarkable efficacy on antipruritus and anti-inflammation with a favorable pharmacokinetic (PK) profile in several mouse models of AD. Thus, these data strongly suggest that our compound <B>48</B> is a promising clinical candidate for treatment of AD.</P> [FIG OMISSION]</BR>

부산지역의 병원간 응급 의료 전달 체계에 대한 연구 : 부산대학교병원 응급의료센터를 중심으로

고필성,조석주 대한응급의학회 1998 대한응급의학회지 Vol.9 No.1

Five hundred and thirty five cases of patients who were transferred to the Department of Emergency Medicine in Pusan University Hospital from Aug 1, 1997 to Aug 31, 1997 and from Oct 1, 1997 to Oct 31, 1997 were studied prospectively. The results were as follows: 1. Total 535 patients were transferred to the emergency department of PNUH(Pusan National University Hospital) for 2 months(average 8.2 a day). Male to female ratio was 1.58:1 and peak age group was 6th decade(17.0% of total). 2. In distribution about arrival time of transferred patients, 40.7% was from 08:00 to 16:00, 39.3% was from 16:00 to 24:00, and 20.0% was from 0:00 to 8:00. 3. Cases that were communicated with the emergency department of PNUH were 7.7%, cases that were communicated with other departments of PNUH were 10.1%, and 82.2% of total cases were transferred without any communication. 4. A 40.7% of patients was transferred by a hospital ambulance, 33.1% of patients used non-emergency vehicles such as taxis or buses, 25.3% of patients was transferred by an 119 or 129 rescue ambulance, and 0.9% was transferred by on foot or others. 5. Transferring hospital was divided into 3 groups; primary hospital, secondary hospital, and university hospital. The majority was secondary hospital(83.6%). 6. The cases that patients wanted to be treated in PNUH were the greatest in number as 55.5%, the cases transferred due to emergency surgery were 9.3%, the cases transferred without specialized department concerned were 28.6%, the cases transferred because of bed deficit were 1.7%, and the cases transferred due to other cause were 4.9%. 7. Traumatic patients were 32.5%, and among them 9.9% was due to motor vehicle accident, among these 78.5% was mild patients. Non-traumatic patients were 67.5% and among them 74.2% was mild patients. 8. Among all transferred patients, 75.7% was admitted for general care, emergency operation, and ICU care. The percentage of discharge was 19.1%, the percentage of death was 2.4%, and the percentage of transfer to other hospital was 2.8%. Generally, because of bed deficit and of availability of operation room, patients were transferred to other hospital. 9. Among specialized departments, the proportion of the department of internal medicine, neurosurgery and pediatrics was 29.3%, 17.2%, and 11.4% respectively. In conclusion, it is considered that proper patient transfer and effective medical service can be achieved through the well-organized EMSS, good triage, and cooperative interhospital communication.

A Novel Network Modeling and Evaluation Approach for Security Vulnerability Quantification in Substation Automation Systems

KO, Jongbin,LEE, Seokjun,LIM, Yong-hun,JU, Seong-ho,SHON, Taeshik 'Institute of Electronics, Information and Communi 2013 IEICE transactions on information and systems Vol.96e.d No.9

The Antioxidant and Anti-inflammatory Activitiy of Ethanol Extract of Aster subulatus Michx

Ju-Yeop Lee,Min-Chul Kang,Ryeo kyeoung Ko,Haeng-Bum Kim,Bong-Seok Kim,Jong-Heon Han,Seong-Hyun An,Gi-Ok Kim 한국생물공학회 2008 한국생물공학회 학술대회 Vol.2008 No.10

Importance of Surgical Order for Minimizing Vascular Injury During the L5-S1 Approach in Multilevel Oblique Lateral Interbody Fusion Surgery

Ju-Sung Jang,Myeong Jin Ko,Young-Seok Lee,Seung Won Park,Seong Hyun Wui 대한신경손상학회 2022 Korean Journal of Neurotrauma Vol.18 No.2

Objective: In oblique lateral interbody fusion (OLIF) surgery at the L5-S1 level (OLIF51), anatomical complexity and the possibility of vascular injury during retraction of the common iliac vein (CIV) make the surgery challenging. We radiologically evaluated patients who underwent OLIF surgery to determine approaches that can make OLIF51 surgery easier during multilevel OLIF. Methods: We retrospectively analyzed 275 consecutive patients who underwent OLIF surgery between September 2014 and December 2019. The distance between the left and right CIVs (dCIV) was measured using an axial image at the L5 lower endplate level, and the height of the iliocaval junction (hCIV) was measured from the L5 lower endplate to the iliocaval junction in the sagittal image. The sum of anterior disc height of each level (sADH) was calculated. Results: Eighty-two patients (33 males and 49 females) were enrolled. The number of three- (L2-3-4-5), two- (L3-4-5), and one-level (L4-5) fusions was 13, 21, and 48, respectively. Changes between the pre- and postoperative sADH, dCIV, and hCIV values were 17.1±4.7, 7.7±3.5, and 13.1±4.7 mm in three-level fusion; 10.6±4.1, 5.6±3.7, and 7.0±3.1 in two-level fusion; and 4.3±2.5, 3.3±2.7, and 3.0±2.0 mm in one-level fusion, respectively. As the number of surgical levels increased, the changes in sADH, dCIV, and hCIV significantly increased. Conclusions: The dCIV and hCIV values increased when the upper segment underwent surgery before OLIF51 during multilevel OLIF.