고주파 유도 가열에 의한 나노구조 Mg₄Al₂Ti₉O₂₅ 합성 및 소결과 기계적 성질

강현수,도정만,윤진국,손인진,Kang, Hyun-Su,Doh, Jung-Mann,Yoon, Jin-Kook,Shon, In-Jin 한국재료학회 2014 한국재료학회지 Vol.24 No.2

Nanocrystalline materials have received much attention as advanced engineering materials with improved physical and mechanical properties, including high strength, high hardness, excellent ductility and toughness. In this study, nanopowders of $Al_2O_3$, MgO and $TiO_2$ were prepared as starting materials by high energy ball milling for the simultaneous synthesis and sintering of the nanostructured compound $Mg_4Al_2Ti_9O_{25}$ by high-frequency induction heating process. The highly dense nanostructured $Mg_4Al_2Ti_9O_{25}$ compound was produced within one minute by the simultaneous application of 80MPa pressure and induced current. The sintering behavior, grain size and mechanical properties of the $Mg_4Al_2Ti_9O_{25}$ compound were evaluated.

급속 소결에 의한 인공관절용 나노구조 2/3 Cr-ZrO₂ 복합재료 제조 및 특성

강현수,강보람,손인진,Kang, Hyun-Su,Kang, Bo-Ram,Shon, In-Jin 한국재료학회 2014 한국재료학회지 Vol.24 No.9

Despite having many attractive properties, $ZrO_2$ ceramic has a low fracture toughness which limits its wide application. One of the most obvious tactics to improve its mechanical properties has been to add a reinforcing agent to formulate a nanostructured composite material. Nanopowders of $ZrO_2$ and Cr were synthesized from $CrO_3$ and Zr powder by high energy ball milling for 10 h. Dense nanocrystalline $2/3Cr-ZrO_2$ composite was consolidated by a high-frequency induction heated sintering method within 5 min at $600^{\circ}C$ from mechanically synthesized powder. The method was found to enable not only rapid densification but also the inhibition of grain growth, preserving the nano-scale microstructure. Highly dense $2/3Cr-ZrO_2$ composite with relative density of up to 99.5% was produced under simultaneous application of a 1 GPa pressure and the induced current. The hardness and fracture toughness of the composite were 534 kg/mm2 and $7MPa{\cdot}m1/2$, respectively. The composite was determined to have good biocompatibility.

움직임 추정오차의 예측을 이용한 고속 움직임 추정 방법

강현수,Kang, Hyun-Soo 한국통신학회 2004 韓國通信學會論文誌 Vol.29 No.9C

This paper presents an enhanced MSEA(multi-level successive elimination algorithm) which is a fast algorithm of the full-search motion estimation. We predict the SAD at the final level using the values of norms at the preceding levels in MSEA and then decide on whether the processing at the following levels should be proceeded or not. We skip the computation at the following levels where the processing is not meaningful anymore. Consequently, we take computational gain. For the purpose of predicting the values of SAD at each level, we first show the theoretical analysis of the value of norm at each level, which is verified by experiments. Based on the analysis a new motion estimation method is proposed and its performance is evaluated. 본 논문은 고속 전역탐색법 중의 하나인 MSEA(multi level successive elimination algorithm)를 개선한 방식으로서, MSEA의 단계에 따른 norm의 계산 결과를 이용하여 최종 단계의 SAD를 예측함으로써 더 이상의 단계를 수행할 필요가 없다고 판단되는 단계의 계산을 생략함으로써 계산 량을 감소시키는 방법을 제안한다. 각 단계별 SAD의 예측을 위해 norm에 대한 이론적 분석이 이루어지며 실험을 통해 분석내용을 검증하고, 이를 바탕으로 새로운 알고리즘을 제안하고 실험을 통해 제안된 알고리즘의 성능을 평가한다.

당근 세균잎마름병에 대한 효과적 방제 수단

강현수,김미진,신용호,전용철,Hyun Su Kang,Mi-Jin Kim,Yong Ho Shin,Yong Chull Jeun 한국식물병리학회 2023 식물병연구 Vol.29 No.4

당근 세균잎마름병을 일으키는 Xanthomonas hortorum pv. carotae는 당근 생산량에 큰 피해를 주는 병 중 하나로 국내에서 아직 방제에 대한 연구가 미흡한 실정이다. 본 연구에서는 당근 세균잎마름병균에 효과적인 농약을 선발하기 위하여 3종의 항생제 streptomycin, oxolinic acid, kasugamycin, 2종의 구리제 copper hydroxide, copper sulfate basic 그리고 길항근권세균 Burkholderia gladioli MRL408-3, Pseudomonas fluorescens TRH415-2, Bacillus cereus KRY505-3을 선정하여 인공배지를 이용하여 이들의 직접적인 항균효과를 조사하였다. 이 중 항생제 streptomycin, oxolinic acid와 길항미생물 MRL408-3을 처리한 배지에서 억제환이 형성되었다. 당근 잎에 농약과 항균효과를 보였던 길항미생물 MRL408-3을 전처리한 후 당근 세균잎마름병균을 접종하였더니 streptomycin과 oxolinic acid을 전처리한 당근 잎에 높은 방제효과를 보였다. 이들 당근 잎 표면의 장방출주사현미경 이미지에서 streptomycin과 oxolinic acid를 전처리한 잎에서는 세균 수가 무처리한 잎과 비교하여 급격히 감소하였다. 이들 결과를 통해 streptomycin과 oxolinic acid와 같은 항생제가 다른 약제에 비해 방제 효과가 뛰어나다는 것을 알 수 있었다. 본 연구는 당근 세균잎마름병에 대한 이상적인 방제 시스템을 구축하는 데 도움이 되는 자료로서 가치가 있을 것으로 생각된다. Bacterial blight of carrot caused by Xanthomonas hortorum pv. carotae (Xhc) is one of the serious diseases of carrot, of which control measures has not been still established in the domestic farm. In this study, in order to select effective sterilizer for bacterial blight of carrots, three antibiotics such as streptomycin, oxolinic acid, kasugamycin, two copper compounds like copper hydroxide and copper sulfate basic and three rhizobacteria Burkholderia gladioli MRL408-3, Pseudomonas fluorescens TRH415-2 and Bacillus cereus KRY505-3 were selected to investigate their direct antibacterial effects using artificial media, aiming to identify effective pesticides against Xhc. Among them, treated medium with antibiotics such as streptomycin, oxolinic acid, and the antagonistic rhizobacteria MRL408-3 were formed inhibition zone. The agrochemicals and the rhizobacteria MRL408-3, which showed antibacterial effects on carrot leaves, pre-treated on the carrot leaves and then inoculated with Xhc. High control effects were shown on the carrot leaves pre-treated with both streptomycin and oxolinic acid. Scanning electron microscopy images of the carrot leaf surfaces showed that the population of bacteria decreased significantly on leaves pre-treated with streptomycin and oxolinic acid. From these results, it can be inferred that antibiotics like streptomycin and oxolinic acid exhibit superior control effects compared to other agents. This study provides valuable insights towards establishing an effective control system for bacterial blight of carrot.

CoAP 기반의 스트리밍 환경에서 사용자 체감품질 향상을 위한 전송량 조절 기법

강현수,박지우,정광수,Kang, Hyunsoo,Park, Jiwoo,Chung, Kwangsue 한국정보과학회 2017 정보과학회논문지 : 시스템 및 이론 Vol.44 No.12

최근 사물인터넷 이용자수의 증가에 따라 IETF(Internet Engineering Task Force)에서 CoAP(Constrained Application Protocol) 표준을 발표하면서 활발한 연구가 진행되고 있다. 그러나 기존 연구들은 자원이 제한적인 사물인터넷 환경에 맞게 전송 단위인 블록을 한 개씩 전송하기 때문에, 낮은 전송량으로 인한 버퍼 언더플로우의 발생으로 스트리밍 서비스에 적용되기 어렵다. 제안하는 기법은 전체 메시지 중 CON(Confirmable) 메시지의 비율을 적응적으로 조절하여 정확한 네트워크 상황을 예측하고, 이를 기반으로 버퍼 점유율, 콘텐츠 다운로드율을 이용하여 블록의 개수를 결정한다. 따라서 버퍼 언더플로우에 의한 재생 끊김을 완화하여 사용자 체감품질을 향상시킨다. 실험 결과를 통하여 제안하는 기법이 네트워크 상황에 따른 전송량 조절로 인해 사물인터넷 스트리밍 환경에서 버퍼 언더플로우 문제를 해결함을 확인하였다. Recently, as the number of Internet of Things users has increased, IETF (Internet Engineering Task Force) has released the CoAP (Constrained Application Protocol). So Internet of Things have been researched actively. However, existing studies are difficult to adapt to streaming service due to low transmission rate that result from buffer underflow. In other words, one block is transmitted one block to client's one request according to the internet environment of limited resources. The proposed scheme adaptively adjusts the rate of CON(Confirmable) message among all messages for predicting the exact network condition. Based on this, the number of blocks is determined by using buffer occupancy rate and content download rate. Therefore it improves the quality of user experience by mitigating playback interruption. Experimental results show that the proposed scheme solves the buffer underflow problem in Internet of Things streaming environment by controlling transmission rate according to the network condition.

폐활성탄을 혼입한 콘크리트의 물리.역학적 성질

강현수,성찬용,Kang, Hyun-Soo,Sung, Chan-Yong 한국농공학회 2009 한국농공학회논문집 Vol.51 No.1

This study was performed to evaluate the physical and mechanical properties of concrete using waste activated carbon. Materials used were ordinary portlant cement, crushed coarse aggregate, natural fine aggregate, waste activated carbon, and superplasticizer. The substitution ratios of waste activated carbon were 0,1,2,3,4,5,6,7,8,9 and 10%. The unit weight was decreased and water absorption ratio was increased with increasing the waste activated carbon content, respectively. When the substitution ratio of waste activated carbon was 3%, compressive strength, flexural strength and dynamic modulus of elastisity were more higher than that of the ordinary portland cement (OPC), and it was decreased with increasing the waste activated carbon content, respectively. The most effective contents of waste activated carbon was 2% in performance and 4% in practical use Accordingly, waste activated carbon can be used for concrete material.

펄스전류 활성 소결에 의한 나노구조 Al2TiO5 화합물 제조 및 기계적 특성

강현수 ( Hyun Su Kang ),박현국 ( Hyun Kuk Park ),도정만 ( Jung Mann Doh ),윤진국 ( Jin Kook Yoon ),박방주 ( Bang Ju Park ),손인진 ( In Jin Shon ) 대한금속재료학회(구 대한금속학회) 2012 대한금속·재료학회지 Vol.50 No.11

Nano powders of Al2O3 and TiO2 compounds made by high energy ball milling were pulsed current activated sintered for studying their sintering behaviors and mechanical properties. The advantage of this process is that it allows very quick densification to near theoretical density and inhibition of grain growth. Nano-structured Al2TiO5 with small amount of Al2O3 and TiO2 was formed by sintering at 1300℃ for 5 minute, in which average grain size was about 96 nm. Hardness and fracture toughness of the nano-structured Al2TiO5 compound with a small amount of Al2O3 and TiO2 were 602 kg/mm2 and 2.6 MPa.m1/2, respectively.

참여정부 균형발전 추진체제에 대한 평가와 과제

강현수(Kang, Hyeon-Su) 한국공간환경학회 2005 공간과 사회 Vol.23 No.-

이 글은 참여정부 균형발전 추진체제의 운영과정에서 드러난 성과와 문제점 및 이를 극복하기 위한 보완방안을 모색하기 위한 것이다. 이를 위해 참여정부 들어와 새로 마련된 국가균형발전위원회, 지역혁신협의회, 국가균형발전특별회계에 초점을 맞추어 그 성과 평가와 향후 과제를 살펴보았다. 결론적으로 참여정부가 추구하는 균형발전 패러다임을 지향하면서 그 성과를 높이려면, 균형발전 추진체제는 조금 더 지방주도형, 지방분권형 구조로 개선되어야 한다. 국가균형발전위원회와 지역혁신협의회의 위상과 역할이 더욱 명료해져야 하며, 균형발전특별회계도 도입취지에 걸맞게 예산 편성과 집행에서 지역의 자율성이 더 높아져야 한다. The Participatory Government set balanced national development as one of the top national agenda in Korea and reformed the enforcement system for it. This paper aims to evaluate the enforcement system for balanced national development, and to suggest the alternative system to improve the process and outcome. For this, the key enforcement system of The Participatory Government such as The Presidential Committee on Balanced National Development, The Regional Innovation Committee, The Special Accounting for Balanced National Development is focused on. The conclusion is that the enforcement system in which regional agents take the strong initiative is better for balanced national development than national government do as like until it did.

세계의 지역혁신 사례 분석 -관련 이론, 성공 요인 및 실패 사례-

강현수 ( Hyun Soo Kang ),정준호 ( Jun Ho Jeong ) 한국응용경제학회 2004 응용경제 Vol.6 No.2

분권과 주민참여를 통한 상향식 지역계획 사례 연구

강현수(Kang, Hyun-Soo) 한국공간환경학회 2013 공간과 사회 Vol.23 No.1

중앙정부가 주도하는 하향식 지역발전 대신 지방정부와 주민이 주도하는 상향식 지역발전에 대한 관심이 높아지고 있다. 1970년대 낮은 경제 수준에도 불구하고 높은 사회 발전을 이룩하여 전 세계에 새로운 발전 모델을 선보인 바 있는 인도의 케랄라 주(州)는 1990년대 말부터 주 정부가 가졌던 권한을 하위 지방자치단체 및 지역 주민에게 획기적으로 이양하는 급진적 지방분권과 아울러 지역발전을 위한 계획과정에 주민들의 직접 참여를 확대하는 “주민계획(People’s Plan)”을 시행해왔다. 철저하게 상향식 방식으로 진행된 케랄라 주 주민계획을 통하여 주민참여와 주민권능부여가 크게 확대되었다. 이 논문에서는 케랄라 주에서 시행하고 있는 상향식 계획과정인 “주민계획”의 추진 배경과 추진 과정, 그 의의와 시사점에 대해 살펴보고자 한다. The Indian state of Kerala has been successfully carrying out decentralization and empowering people and local communities, especially through the 'People's Plan' since 1990s. People’s plan of Kerala started the devolution of control of decisions and budgets for local development from a centralized bureaucracy to local communities and ordinary people. Through People’s plan, local people could participate in planning process, and determine and implement their development projects by themselves with their own priorities. This paper aims to comprehend overall evolving process of the People’s plan in Kerala from the campaign phase to the institutional phase since 1990s, and to analyse the characteristics and implications of Kerala's unique experiments in the world.