IPv6 환경에서의 일방향 통신 알고리즘에 대한 연구

고근호,안성진 한국융합보안학회 2017 융합보안 논문지 Vol.17 No.5

1990년대 초반에 IETF(Internet Engineering TaskForce)는 IPv4의 주소 고갈 문제에 대한 임시해결책인 CIDR(Classless Inter-Domain Routing), NAT, 사설 IP 주소 등의 도입과 함께 기존 IPv4 주소 체계에서의 많은 단점들을 수정 및 보완할 수 있는 새로운 주소체계 도입에 관한 논의를 시작하였다. 그 결과 새로운 주소 체계와 관련된 다양한 표 준안들이 제안되었는데, 이들 중 가장 발전 가능성이 높은 방안으로 SIPP(Simple Internet Protocol Plus)가 채택되어 지금 의 IPv6로 발전하였다. 기존의 IPv4에서 실시간 데이터의 처리 능력과 QoS 관련 성능, 보안, 라우팅의 효율성 등의 많은 분야와 관련하여 부족했던 부분들이 수정 및 보완됨과 동시에 새로운 개념들이 도입되었다. 하지만 IPv6 환경에서도 보안 을 위협할 만한 다양한 요소들이 존재하며, 이에 따라 안정적인 데이터 통신 환경의 필요성이 꾸준히 제기되어 왔다. 본 논문에서는 일방향으로 데이터를 전송하면 불확실하고 잠재적인 위협 요소로부터 시스템을 보호할 가능성이 높아진다는 점에 착안하여, IPv6 환경에서의 일방향 통신 알고리즘을 개발하였다. 먼저 기반 환경인 IPv6 및 ICMPv6에 대해 조사 및 분석하고 그에 따른 해결방안인 일방향 통신 알고리즘을 제시한다. In the early 1990s, IETF(Internet Engineering TaskForce) had started the discussion on new address protocol that can modify and supplement various drawbacks of existing IPv4 address protocol with the introduction of CIDR(Classless Inter-Domain Routing) which is a temporary solution for IPv4 address depletion, NAT, private IP address. While various standards related to new address protocol has been proposed, the SIPP(Simple Internet Protocol Plus) was adopted among them because it is regarded as the most promising solution. And this protocol has been developed into current IPv6. The new concepts are introduced with modifying a lot of deficiencies in the exisitng IPv4 such as real-time data processing, performance on QoS, security and the efficiency of routing. Since many security threats in IPv6 environment still exist, the necessity of stable data communication environment has been brought up continuously. This paper deveopled one-way communication algorithm in IPv6 based on the high possibility of protecting the system from uncertain and potential risk factors if the data is transmitted in one way. After the analysis of existing IPv6 and ICMPv6, this paper suggests one-way communication algorithm as a solution for existing IPv6 and ICMPv6 environment.

법랑질 접착에 대한 습윤 효과

고근호,조영곤,진철희,유상훈,김종욱,박병철,기영재,최희영,김종진 大韓齒科保存學會 2004 Restorative Dentistry & Endodontics Vol.29 No.3

This study evaluated the microleakage and interfacial gap between enamel and composite resin under the dry and wet condition of the enamel surface, V shaped class 5 cavities were prepared on the occlusal portion of extracted human molars. Samples were divided into three groups: D group (air dry for 10-15s), BD group (blot dry with moist cotton pellet), and DR group (air dry for 10-15s and rewet with Aqua-Prep F for 20s). Cavities were filled using Aelitefil composite resin after applied One-Step. Microleakage was tested by 2% methylene blue dye solution and the data were statistically analysed by Kruskal-Wallis test and Mann-Whitney test. Also Enamel-resin interface was observed under SEM. Group BD showed statistically lower microleakage than group D (p〈0.05). but there was no statistically significant difference between group BD and DR (p)0.05). At the enamel-resin interface, group D showed the gap of 2 ㎛ thickness, but group BD and DR showed close adaptation. In conclusion, the use of blot dry and rewetting agent (Aqua-Prep F) resulted in decreased microleakage and improved adhesion between enamel and resin when using One-Step.

사물인터넷 환경에서의 보안 관제 방향에 관한 연구

고근호,이성렬,안성진 한국융합보안학회 2015 융합보안 논문지 Vol.15 No.5

정보통신기술의 급진적인 발달로 인해 우리 주위의 모든 사물들이 인터넷으로 연결되어 서로 정보를 주고받으며 각각의 사물들이 제공하던 것 이상의 새로운 가치를 제공하는 사물인터넷(IoT) 시대를 맞이하고 있다. 사물인터넷 환경에서는 기존과 다르게 인터넷에 연결되는 사물의 수가 급격히 증가하기 때문에 그만큼 보안 위협도 많아지게 될 것이다. 또한 셀 수 없이 많은 사물들을 어떻게 보호하고 관리할 것인지에 대해 새롭게 생각해 볼 필요가 있다. 본 논문에서는기존의 보안 관제의 역할과 절차에 대해 살펴본다. 아울러 IoT 환경에서의 보안 관제의 방향에 대해 소개한다. With radical development of information and communication Technology, Internet of Things(IoT) era – all the th ings around us are connected through internet so that it enables objects to exchange data with connected devices a nd is expected to offer new advanced services that goes beyond the value where each existing objects could have o ffered respectively - has come. Concerns regarding security threat are being raised in adopting IoT as the number of internet-connected appliances are rapidly increasing. So, we need to consider how to protect and control countles s objects. This paper covers the role and procedures of existing security control. Futhermore, it provides information about the direction of security control when it comes to IoT.

Photoelectrochamical characteristics of WO₃ on metal substrate for hydrogen production

고근호(Go, GeunHo),서선희(Seo, SeonHee),Shinde, Pravin S.,이동윤(Lee, Dongyoon),이원재(Lee, Wonjae) 한국신재생에너지학회 2011 한국신재생에너지학회 학술대회논문집 Vol.2011 No.11

Transparent conducting oxides (TCOs) supported on glass are widely used as substrates in PEC studies for photovoltaic hydrogen generation applications However, high sheet resistane (10{sim}15{Omega}/cm²) and fragileness of glass-supported TCO substrates are the obstacles to produce the large area PEC cells. Such internal sheet resistance is detrimental to efficient collection of photogenerated majority charge carriers at the photoactive material and electrolyte interface. Moreover, these TCO substrates are very expensive and consume about 40~60% cost of the devices. Hence, a low sheet resistance of the substrate is a key point in improving the performance of PEC devices. Metallic substrates coated with a photoactive material would be a good choice for efficient charge collection. Such metal substrates based photanodes are best candidate for large-scale phtoelectrochemical water splitting for hydrogen generation. In this study, we report the enhanced PEC performance of WO₃ film on metal(chemical etched, bare) substrate. It is proposed that interface between WO₃ and the metal substrate is responsible for efficient charge transfer and demonstrated significant improvement in the photoelectrochmical performance. X-ray diffration and FESEM suduies reveled that WO₃ films are monoclinic, porous, polycrystalline with average grain size of ~50nm. Photocurrent of WO₃ prepared on metal substrates was measured in 0.5M H₂SO₄ electroyte under simulated 100mW/cm² illumination.

음 인식 및 악보 인식 알고리즘에 대한 연구

고근호(Keun Ho Koh),김규서(Kyu Seo Kim),황선욱(Sun Wook Hwang),양창진(Chang Jin Yang) 한국정보과학회 2018 한국정보과학회 학술발표논문집 Vol.2018 No.12

IPS Empress(R)2 system 을 이용한 라미네이트 비니어 수복

박일윤(Il Yoon Park),고근호(Keun Ho Ko),김명조(Myung Cho Kim) 조선대학교 구강생물학연구소 2002 Oral Biology Research (Oral Biol Res) Vol.26 No.1

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상아질 접착제에 함유된 용매의 종류에 따른 접착능에 관한 연구

박일윤(Il Yoon Park),고근호(Keun Ho Ko),조공철(Gong Chul Cho) 조선대학교 구강생물학연구소 2002 Oral Biology Research (Oral Biol Res) Vol.26 No.1

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안정적인 데이터 공유를 위한 일방향 전송 알고리즘에 대한 연구

강민경,고근호,안성진 한국융합보안학회 2016 융합보안 논문지 Vol.16 No.7

국네트워크를 통한 데이터의 공유로 인해 각종 분야에서 첨단 응용 연구 성과를 보여 왔다. 그만큼 이에 적합한 안정적 데 이터 공유 환경의 필요성 역시 꾸준히 제기되었다. 본 연구에서는 이러한 필요성에 따라 등장한 여러 성과 중 일방향 통신 지 향 프로토콜에 대해 다룬다. 이 프로토콜은 오직 일방향만으로 데이터를 전송토록 하는 체계이다. 이는 불확실하고 잠재적인 위협 요소로부터 시스템을 지켜낼 가능성이 높아지지만, 데이터에 대한 확인/응답(ACK) 패킷을 전혀 받을 수 없다. 따라서 TCP, ICMP와 같은 양방향 프로토콜이 제대로 작동하면서 실질적인 통신이 이루어지도록 해야 한다. 이에 따라 본 연구에서 는 인터페이스 계층, 인터넷 계층, 전송 계층에 대해서 각각 존재하는 프로토콜별 가능한 시나리오에 대해 분석하고 각각의 해 결방법에 대해 접근하였다. As many high-tech researches are shown in various field by sharing data via computer network, a necessity for stable data-sharing environment has suggested steadily. This research covers one-way communication protocol which is newly developed through the necessity. In this protocol, data is transmitted only in one way. One-way transmission has strong possibility to protect system from uncertain and potential risk, but it is impossible to receive ACK(Acknowledge Character) packet about data. Therefore, we need to find a way which duplex protocol such as TCP, ICMP works properly and practical communication falls under one-way transmission environment. To conclude, we analysed possible scenario in each protocol from three layers - interface layer, internet layer and transmission layer and approached how to resolve the problem in each way.

PEC용 광 물분해에 관한 연구

이원재,고근호,Pravin S. Shinde 한국에너지학회 2010 한국에너지공학회 학술발표회 Vol.2010 No.10

응축형 복합레진 수복시 유동성 레진 이장이 변연부 미세누출에 미치는 영향

문주훈,고근호 대한치과보존학회 2001 Restorative Dentistry & Endodontics Vol.26 No.1

The purpose of this study was to evaluated the marginal microleakage of condensable composite resin restorations according to flowable resin lining of internal cavity wall. The eighty extracted human molar teeth without caries and/or restorations are used. The experimental teeth were randomly assigned into four groups of ten teeth each. Eighty caries-free extracted human molars were used in this study. The conventional class Ⅱ cavities (box-shaped on mesial and distal surface, faciolingual width : 3mm, gingival wall depth : 1.5mm) were prepared 1mm below comentoenamel junction with a # 701carbide bur. The teeth were divided into four groups, and then each group were subdivided into A & B group according to flowable resin & compomer lining : Group 1-A : Tetric Ceram filling. Group 1-B : Tetric Flow lining and Tetric Ceram filling, Group 2-A : Ariston pHc filling, Group 2-B : Tetric Flow lining and Ariston pHc filling, Group 3-A : SureFil filling, Group 3-B : Dyract Flow lining and SureFil filling. Group 4-A : Pyramid filling, Group 4-B : Aeliteflo lining and Pyramid filling. To simulate as closely as possible the clinical situation during retoration placement, a "restoration template" was fabricated, and the condensable resin was filled using a three-sited light-curing incremental technique. All the materials used were applied according to the manufacturers' instructions. The specimens were stored in the 100% humidity for 7 days prior to thermocycling (100 thermal cycles of 5~55℃ water with a 30-second dwell time). The specimens were immersed in 2% metyleneblue dye for 24 hours, and then embedded in transparent acrylic resin and sectioned mesiodistally with diamond wheel saw. The degree of marginal leakage was scored under stereomicroscope (x20) and the data were analyzed by Kruskal-Wallis test and Wilcoxon follows : The results were as follow : 1.In the gingival margins of all the group, microleakage of subgroup B was less than subgroup A. 2.In the group 1, 2, 4 there was significant differences between subgroup A and B (p<0.05), but in the group 3, there was not significant different between group 3-A (SureFil) and group 3-B (Dyract flow/SureFil) (p>0.05). 3.In the subgroup A and B, there was significant different between all group except group 4 of subgroup A. From the results above, it was suggested that the cavity lining of flowable resin and flowable compomer in condensable resin restoration decrease microleakage at gingival margin, and does improve their ability to seal the gingival margin of class Ⅱ preparation. Key words : Posterior composite resin restoration, Condensable composite resin, Flowable resin lining, Marginal microleakage.