생태계의 사회주의적 개조: 북한의 폐흡충 박멸 사업, 1955-1961

곽희환,정준호,김옥주 한국과학사학회 2018 한국과학사학회지 Vol.40 No.3

For centuries, the Korean peninsula was a major endemic area of Paragonimiasis. North Korea, which had many major endemic foci, focused on the eradication of Paragonimiasis since the early days of na- tion-building. During the period of the first economic development plan, Paragonimiasis became one of the main obstacles for the development of North Korea, as it degraded labor power. In 1995, North Korean para- sitologists adopted the “Devastation” method from the USSR. This was “aggressive prevention through attacking and eradicating every possible de- velopmental stages of parasite from egg, larvae to adults.” Completion of the agricultural cooperative and the socialist economic system in 1958 al- lowed mass mobilization in the rural areas. North Korea conducted an in- tensive eradication effort through mass mobilization of women and students. They captured dozens of tons of intermediate host snails and car- ried out comprehensive hydrotechnical engineering projects on the river ecosystem. Paragonimiasis prevention dispensaries were established in each village to provide mandatory treatment to residents. As a result of this pro- gram, North Korea declared the eradication of Paragonimiasis in 1961. This program, implemented during the socialist nation-building period, was not only a socialist remodeling of the production system and people’s ideology, but also a wider remodeling of the ecosystem that provided the physical basis for socialist life.

Eosinophilic granulomatosis with polyangitis after COVID-19 vaccination - Case Report

곽희환,황유경,김세훈,장윤석 대한내과학회 2022 대한내과학회 추계학술대회 Vol.2022 No.2

연강의 습식 수중 아크 용접 특성에 관한 연구

곽희환(H. H. Kwak),김창규(C. G. Kim),김민남(M. N. Kim) 한국동력기계공학회 2004 한국동력기계공학회 학술대회 논문집 Vol.- No.-

Underwater wet arc welds were experimentally performed on 11mm thick SS400 mild steel plate as base metal by using six different types of flux coated electrodes of 4.0mm diameter; KSKR, KSKT, USBL, JPUW, UWEA, and UWES. As results, the developed flux coated underwater electrode had a good weldability compared with other domestic terrestrial electrodes. By rapid cooling rate, the hardness value of HAZ were increased by quenching effects. Mechanical properties for the multi-pass butt-welding specimen are also tested experimentally. The feasibility of the developed underwater electrode was experimentally studied and the results achieved in this wet arc welds have shown that the developed wet welding electrode UWEB can have a degree of integrity.

연강의 습식 수중 아크 용접 특성에 관한 연구

곽희환(H. H. Kwak),김창규(C. G. Kim) 한국동력기계공학회 2007 동력시스템공학회지 Vol.11 No.1

Underwater wet arc welds were experimentally performed on 11mm thick SS400 mild steel plate as base metal by using six different types of flux coated electrodes of 4.0mm diameter; KSKR, KSKT, USBL, JPUW, UWEA, and UWEB. As results, the developed flux coated underwater electrode had a good weldability compared with other domestic terrestrial electrodes. By rapid cooling rate, the hardness value of HAZ were increased by quenching effects. Mechanical properties for the multi-pass butt-welding specimen are also tested experimentally. The feasibility of the developed underwater electrode was experimentally studied and the results achieved in this wet arc welds have shown that the developed wet welding electrode UWEB can have a degree of integrity.

선체용 압연 강판의 습식 수중 아크 용접부의 부식특성에 관한 연구

곽희환(H. H. Kwak),김창규(C. G. Kim),김민남(M. N. Kim),황성훈(S. H. Hwang) 한국동력기계공학회 2005 동력시스템공학회지 Vol.9 No.4

Underwater wet arc welds were experimentally performed on 11mm thick KR-RA steel plate using six different types of flux coated electrodes of 4.0mm diameter, KSKR, KSKT, USBL, JPUW, UWEA and UWEB. From analysis of bead appearance, detachability of weld slag, spatter occurrence and arc stability, JPUW gives the best result, and UWEB is superior to KSKR and KSKT. By experimental result of hardness distribution on the weld bonds, UWEB weld has the narrowest bond structure which is probable condition to get the best mechanical properties of weld. UWEB and JPUW welds have more even hardness distribution across weld deposit and base metal. Upon polarization test to measure the respondency of corrosion, the electrode of UWEB shows the most excellent degree due to the low open circuit potential difference.

산체용 압연 강판의 습식 수중 아크 용접부의 부식특성에 관한 연구

곽희환(H.H. Kwak),김창규(C.G. Kim),김민남(M.N. Kim),황성훈(S.H. Hwang) 한국동력기계공학회 2006 동력시스템공학회지 Vol.10 No.4

Underwater wet arc welds were experimentally performed on 11㎜ thick KR-RA steel plate using six different types of flux coated electrodes of 4.0㎜ diameter, KSKR, KSKT, USSL, JPUW, UWEA and UWES. From analysis of bead appearance, detachability of weld slag, spatter occurrence and arc stability, JPUW gives the best result, and UWES is superior to KSKR and KSKT. By experimental result of hardness distribution on the weld bonds, UWES weld has the narrowest bond structure which is probable condition to get the best mechanical properties of weld. UWES and JPUW welds have more even hardness distribution across weld deposit and base metal. Upon polarization test to measure the respondency of corrosion, the electrode of UWES shows the most excellent degree due to the low open circuit potential difference.

Process Algebra Based Symbolic Verification Framework for Software-Defined Networking

신명기,곽희환,최진영,강미영 에스케이텔레콤 (주) 2013 Telecommunications Review Vol.23 No.5

There have been continuous efforts and progresses regarding the research on the verification for Software Defined Networks (SDN), since incomplete or malicious programmable SDN entities could cause break-down of underlying networks shared by heterogeneous devices and stake-holders. In SDN world, it becomes important to verify the safety properties of SDN using formal method before the deployment of SDN applications. In this paper, we propose VeriSDN, a novel framework for the symbolic verification of SDN based on the formal method, especially with process algebra called pACSR which is an extended version of packet based Algebra of Communicating Shared Resources (ACSR). In our framework, OpenFlow’s flow tables are translated into pACSR descriptions and analyzed by means of a symbolic algorithm. The result will be the Boolean expression that satisfies when the property holds. pACSR processes are well suited to expresses concurrently running communicating switches and a controller. Packets in SDN can be described in pACSR as parameters passed via channels and handled with predefined predicates (PP) and be modified with predefined functions (PF). Even though our method is developed mainly for verification of the off-line case where flow tables are dynamically modified, however, we believe that it can be applied to the running switches with reasonable numbers. Furthermore, our method is transparent to the operators so the underlying verification process is hidden to the operators and there is no burden to understand the details of formal verification method by the operators.

주철과 오스테나이트계 스테인리스강과의 확산접합에 관한 연구

김창규,곽희환,문윤길 釜慶大學校 2000 釜慶大學校 論文集 Vol.5 No.-

Effects of the diffusion bonding on the mechanical properties for the GCD45 /austenitic stainless steel(STS304) bonding specimens have been investigated. The results are obtained as follows ; 1) In the case of GCD45/STS304 specimen made on air, the bonding tensile strength increased with increasing bonding temperature. The maximun bonding tensile strength was 467.5MPa at 1373K. 2) The bonding tensile strength of GCD45/STS304 made by using insert metal MBF35 increased with increasing bonding time, and was about 470MPa at the conditions of bonding temperature 1323K, bonding time 1.8Ks and bonding pressure 9.8MPa. 3) The bonding tensile strength of GCD45/STS304 made by using the insert metal was higher than that of direct bonding specimen.

SDN 서비스 검증 기술

강미영,곽희환,최진영,신명기 한국컴퓨터통신연구회 2015 OSIA Standards & Technology Review Vol.28 No.2

주철의 재질에 미치는 각종 Steel scrap의 영향

김홍범,한용남,곽희환,이종문,김찬규 한국자원리싸이클링학회 2000 資源 리싸이클링 Vol.9 No.1

Zn을 많이 함유하는 銅scrap(자동차용강판, Zn표면처리강판 등)을 이용하여 구상흑연주철을 제조한 경우 구상화가 제대로 이루어 지지 않았다. Sb을 많이 함유하는 銅scrap을 이용하여 구상흑연주칠을 제조한 경우에는 기지 층의 퍼얼라이트량이 증가하였다. 퍼얼라이트량이 증가하면 인장강도 및 경도는 증가하지만 연산율은 감소하였다. Mn, Cr을 많이 함유한 銅scrap(기계구조용강판, 가단주철)을 이용하여 구상흑연주출을 제조한 경우에는 피얼라이트량이 증가하였으며, 인장강도 및 경도도 증가하였다. The effect of different kinds of steel scraps, the raw material in the manufacturing of nodular cast iron, on the microstructures and mechanical properties has been investigated Different grades were produced by changing the steel scraps. When nodular graphite cast iron was produced by using Zn rich steel scrap, such as galvanized steel sheet and auto body sheet, mechanical properties were deteriorated due to the decomposition of graphite, so close control must be maintained over this element. Tensile strength and hardness of nodular graphite cast iron which were manufactured by using Sb rich steel scrap were increased while elongation was decreased due to the increased amounts of pearlite within matrix. Mn and Cr contents in the structural steel sheet scrap or malleable iron scrap increased tensile strength and hardness of nodular graphite cast iron by facilitating the formation of pearlite.