USN에서 중간 노드에서의 보고서 검증 시도 확률 평가 함수를 이용한 에너지 효율 향상 기법

이현우,문수영,조대호,Lee, Hyun-Woo,Moon, Soo-Young,Cho, Tae-Ho 한국시뮬레이션학회 2011 한국시뮬레이션학회 논문지 Vol.20 No.4

무선 센서 노드들은 개방된 환경에서 동작하기 때문에 외부의 물리적인 공격에 매우 취약하다. 공격자는 노드들을 훼손시켜서 센서 네트워크에 허위 보고서를 주입시킬 수 있다. 이러한 공격들은 센서 노드들의 에너지를 고갈시킨다. 이에 대응하는 보안 기법으로 Ye등은 중간 노드가 일정한 확률로 보고서를 검증하는 통계적 여과 기법을 제안하였다. 통계적 여과 기법은 모든 중간 노드가 같은 확률로 보고서 검증을 수행한다. 따라서 정상 보고서와 허위 보고서를 검증하는데 같은 에너지가 소모 되므로 정상 보고서를 검증하는데 불필요한 에너지를 소모하게 된다. 본 논문에서는 각 중간 노드가 보고서 검증 시도 확률을 조절하여 센서 노드들의 에너지 소모량을 줄이는 기법을 제안한다. 보고서 검증 시도 확률은 한 노드의 잔여 에너지양, 현재 노드에서 기지 노드까지의 홉 수, 허위 보고서의 비율에 의해 결정된다. 보고서 검증 시도 확률을 조절하여 통계적 여과 기법과 비슷한 보안성을 유지하면서 에너지의 효율성을 높일 수 있다. Wireless sensor nodes operate in open environments. The deployed sensor nodes are very vulnerable to physical attacks from outside. Attackers compromise some sensor nodes. The compromised nodes by attackers can lead to false data injection into sensor networks. These attacks deplete the limited energy of sensor nodes. Ye et al. proposed the Statistical En-Route Filtering (SEF) as a countermeasure of the attacks. The sensor node in SEF examines the event reports based on certain uniform probability. Thus, the same energies are consumed in both legitimate reports and false reports. In this paper, we propose a method that each node controls the probability of attempts to verify a report to reduce energy consumption of sensor nodes. The probability is determined in consideration of the remaining energy of the node, the number of hops from the node to SINK node, the ratio of false reports. the proposed method can have security which is similar with SEF and consumes lower energy than SEF.

$90^{\circ}C$위상차의 이축하중 하에서 A17075-T651의 부가적 손상에 관한 결정구조 의존성에 관한 연구

이현우,오세종,Lee, Hyun-Woo,Oh, Se-Jong 대한기계학회 1997 大韓機械學會論文集A Vol.21 No.1

Accounting for the additional damages come out from non-proportional loading path effect, material damage according to crystal structure dependence was studied. Microscopic observations of damaged material by SEM(Scanning Electron Microscope) showed crystal structure dependence. Biaxial in-phase loaded specimens showed the slips of same direction, which pararell each other, but biaxial 90.deg. out-of-phase loaded specimens showed multiply crossed slips. S. H. Doong and D. F. Socie reported that wavy/planar or planar slip material showed the increase in the cyclic hardening level during non-proportional cycling. From these results, the additional hardening and non-proportional loading effects were related with slip mechanism, and the slip mechanism was related with crystal structure. In the present study, a damage mechanism which accounts for the non-proportional loading effect from crystal structure dependence was considered and applied to A17075-T651.

소형화된 1.6 GHz 단일 채널 도플러 센서를 이용한 실시간 호흡 및 심장 박동 감지기

이현우,박일호,김동욱,Lee, Hyun-Woo,Park, Il-Ho,Kim, Dong-Wook 한국전자파학회 2007 한국전자파학회논문지 Vol.18 No.4

본 논문에서는 사람의 생체 신호를 감지하기 위해 1.6 GHz 단일 채널 도플러 센서와 아날로그 및 디지털 신호 처리부로 구성되어 있는 실시간 호흡 및 심장 박동 감지기를 개발하였다. 도플러 센서의 RF Front End는 발진기, 믹서, 저잡음 증폭기, 브랜치-라인 하이브리드, 그리고 패치 안테나로 구성되어 있다. 센서에 사용된 브랜치-라인 하이브리드는 기존의 하이브리드에 비해 40 % 정도 크기를 줄이면서도 상당히 유사한 성능을 가지도록 인공 전송 선로(artificial transmission line)를 사용하였다. 아날로그 신호처리부는 2차 Sallen-Key 능동 필터를 사용하여 제작되었고 디지털 신호 처리부는 LabVIEW를 사용하여 컴퓨터상에서 구현되었다. 개발된 시스템은 최대 50 cm 거리에서 사람의 호흡과 심장 박동을 측정함으로써 성능을 검증하였다. This paper presents a real-time respiration and heartbeat detector comprised of a 1.6 GHz single-channel Doppler sensor and analog/digital signal processing block for remote vital sign detection. The RF front end of the Doppler sensor consists of an oscillator, mixer, low noise amplifier, branch-line hybrid and patch antenna. We apply artificial transmission lines(ATLs) to the branch-line hybrid, which leads to a size reduction of 40 % in the hybrid, while its performance is very comparable to that of a conventional hybrid. The analog signal conditioning block is implemented using second order Sallen-Key active filters and the digital signal processing block is realized with a LabVIEW program on a computer. The respiration and heartbeat detection is demonstrated at a distance of 50 cm using the developed system.

자락요법과 고백반 도포로 호전된 급성 편도선염 소아환자의 임상연구

이현우,홍승욱,Lee, Hyun-Woo,Hong, Seung-Ug 대한한방안이비인후피부과학회 2012 한방안이비인후피부과학회지 Vol.25 No.1

Objectives : The purpose of this study is to research the effect of bloodletting therapy and Alunitum-spread at palatine tonsil in acute tonsillitis. Methods : We reviewed medical records of 61 young patients of acute tonsillitis who had taken bloodletting therapy and Alunitum-spread from May 2003 to March 2011 in Samsung oriental medicine clinic. Results : There were 39 boys and 22 girls. Between 5 and 6 years-old group was more than the others. Between 3 and 4 days group was the first in duration of disease. Winter was the first and then spring, fall and summer in distribution of season. Between 9 and 10 days group was 22 patients, which was the first in duration of treatment. it was the first to have no history of acute tonsilitis group, and then cold, allergic rhinitis, laryngopharyngitis, acute tonsillitis and tympanitis. There were 41 patients who came to Samsung oriental medicine clinic the first and then western clinic, home remedy and other oriental clinic. Sore throat was the first sympton and then runny nose, high fever, nasal congestion and cough in companied symptom. Conclusions : Bloodletting therapy and Alunitum-spread were useful to improve acute tonsillitis.

고속 공중 무선랜 시스템을 위한 효율적인 연결 요청 제어방법의 성능분석

이현우,김세한,류원,윤종호,Lee Hyun woo,Kim Se han,Ryu Won,Yoon Chong ho 한국통신학회 2005 韓國通信學會論文誌 Vol.30 No.3a

본 논문은 무선랜 기술을 활용한 초고속 무선인터넷 서비스에서 사용자 단말의 최대 성능을 얻기 위해 효과적으로 AP를 선택하고 연결을 설정하는 방식에 관한 것이다. IEEE 802.11에 기반한 공중 무선랜 환경에서 AP의 탐색과정을 수동형과 능동형으로 분류하고, 본 논문에서는 수동형 AP탐색 과정은 무선랜 접속장치(AP:Access Points) MAC계층에서 단말에 미디어 접근정보를 방송으로 알려주는 비콘(Beacon)프레임을 이용하고, 능동형 AP 탐색과정에서는 AP의 조사응답(Probe Response) 메시지 프레임을 이용하여 무선랜 단말에게 현재 AP에 연결(association)되어 있는 단말 갯수와 처리중인 트래픽량을 알려주는 방식을 제안한다. 단말에서는 RSSI, AP에 연결된 단말의 갯수와 처리하는 트래픽량의 정보를 종합적으로 검토하여 효율면에서 가장 유리한 AP를 선택하여 연결을 설정하면 다수의 사용자가 동시에 사용하는 핫스팟 환경에서도 최대성능을 얻을 수 있으며, 사업자입장에서는 사용자의 분산으로 자원과 망 관리 효율 면에서 상당한 효과가 있음을 시뮬레이션을 통하여 검증하였다. This paper generally relates to the field of wireless local area networks(WLANs), and more particularly, to AP selection and association methods for the performance of a station. In these days, IEEE 802.11 Wireless LAN network is widely deployed and used as an emerging service to connect high-speed Internet in the public wireless environment. But, if there are many users in hot spot area, they suffer a severe decrease of performance. Thus it needs an association and access control mechanism especially when it is used in the public environment. In this paper, we suggest a selection and association method using Beacon or Probe Response frames based IEEE 802.11. Station selects AP using the information of the capacity area in a Beacon or a Probe Response frame. According to the present paper, an association method for a public WLAN service, which includes a WLAN user terminal and an AP for relaying WLAN communications to and from the user terminal, includes the steps of the user terminal asking the AP's states for access to a radio channel; and the station selects and associates with the AP According to the above-described selection in a high speed wireless Internet service based on public WLAN technologies that are currently in operations. Further, it is possible to improve the efficiency of network management.

Active Learning과 군집화를 이용한 고정키어구 추출

이현우,차정원,Lee, Hyun-Woo,Cha, Jeong-Won 대한음성학회 2008 말소리 Vol.66 No.-

We describe a new active learning method in conditional random fields (CRFs) framework for keyphrase extraction. To save elaboration in annotation, we use diversity and representative measure. We select high diversity training candidates by sentence confidence value. We also select high representative candidates by clustering the part-of-speech patterns of contexts. In the experiments using dialog corpus, our method achieves 86.80% and saves 88% training corpus compared with those of supervised method. From the results of experiment, we can see that the proposed method shows improved performance over the previous methods. Additionally, the proposed method can be applied to other applications easily since its implementation is independent on applications.

백호탕가미방으로 치료한 수족다한증 치험 3례

이현우,홍승욱,Lee, Hyun-Woo,Hong, Seung-Ug 대한한방안이비인후피부과학회 2006 한방안이비인후피부과학회지 Vol.19 No.2

Hyperhidrosis of the palms and soles, regardless of race or sex, often occurs in the childhood or adolescence. Generally this symptom, whose definite cause is not known, worsens in the emotional state of anxiety and nervousness. Although this symptom is likely to interfere with one's daily life including career activities and to give a sense of mental oppression, no treatment is yet to bring a successful result. Amid the hyperhidrosis of the palms and soles patients, we applied 'bakhotang-gamibang' and acupuncture treatment to the three patients who has heat in the stomach. We hereby inform results of the improvement in the symptom of those patients.

거창 고학리 해주오씨의 장소애착을 통해 본 종족경관의 형성과정

이현우,Lee, Hyun-Woo 한국조경학회 2013 韓國造景學會誌 Vol.41 No.5

This research, which sought to conjecture the formation process of tribal landscape while confirming the method and characteristic of place attachment of the Haeju Oh Family, which is rooted within the village and the Yongwon Pavilion and Garden of Gohak-ri, Mari-myeon, Geochang-gun, Gyeongnam, reached the following conclusion based on the interpretation and analysis of cultural and scenic elements such as the names and sculptures nearby the village and Yongwon Pavilion and Garden. This place is where Goohwagong Oh Sue, a Haeju person, settled down. This is also where his descendants were refined while yearning for their ancestors. The Yongwon Pavilion was established in 1964. It can be sufficiently known that this place was managed and maintained as a garden-like place where the spirit of yearning was shared and which was the basis of the life and entertainment of descendants after being the monumental place for Master Oh Guhwa, through stories, documents, nearby facilities, and writings on many rocks. It is clear that the meaning of 'Bang-Hak(訪鶴) and Jung-Hak (停鶴)' which is carved in many places around this area and Gohak-ri, which symbolizes the Hakbong(crane peak), the vein of Wonjak-dong which is one of the Ahneuisamdong(three outstanding scenic places of Ahneui), is a scenic language explaining the ecological settlement and lives of the Haeju Oh Family. When considering the definition of a sense of place as "a 'social device' made by discussions and practice rather than its existing as a substance," the many structures scattered around the village, Yongwon Pavilion Garden, and nearby designations show the monumental place inheritance of tribal group clearly exhibiting the characteristics of a Korean sense of place. Ever since Guhwagon Oh Sue settled down in Guhak-ri, the tribal group of Haeju Oh Family went through a life settlement phase and landscape formation phase by realizing the sense of place. Afterwards, while yearning for ancestors and repeatedly rooting down in the place, territoriality expanded and the place was reproduced. In particular, timber houses and monuments were constructed during the Japanese Colonization Period, and after independence, the Yongwon Pavilion was constructed through place reproduction, and monumental tribal landscape is currently being expressed in various forms to this day. Thus, allowing to reach the conclusion of 'Tribal Landscape of Gohak-ri, Mari-myeong, Geochang-gun,' which we perceive today. The products of territorial expansion formed by the repeating phenomenon of place rootedness and place attachment by tribal groups are in fact the substance of tribal landscape. Through such, it is possible to confirm the true spirit of place attachment and the earnest interest and affection of descendants towards a unique place that is repeatedly constructed and inherited within the group memory. 경남 거창군 마리면 고학리에 소재한 용원정원림(龍源亭園林) 및 마을주변의 지명과 조형물 등 문화경관적 요소들에 대한 분석과 해석을 토대로 용원정원림과 마을 내 배태(胚胎)된 해주오씨의 장소애착 방식과 특질을 확인하는 한편, 종족경관(宗族景觀)의 형성과정을 추찰하고자 한 본 연구의 결론은 다음과 같다. 해주인 구화공 오수(九華公吳守)가 마을에 터 잡은 이래 그의 후손들이 선조를 사모하는 마음으로 다듬어 온 공간으로 1964년 용원정이 건립되었다. 이곳은 구화공의 유허지로 이후 후손들의 생활과 풍류의 거점이자 숭모(崇慕)의 정을 교감하는 원림적 장소로서 지속적으로 관리되어 왔음이 기문과 문헌자료 그리고 주변에 배치된 여러 시설 및 다수의 바위에 새긴 바위글씨를 통해서도 충분히 감지된다. 안의삼동 중 하나인 원학동의 지맥인 학봉(鶴峰)을 상징하는 고학리와 이곳에 각인된 '방학(訪鶴) 정학(停鶴)'의 의미는 해주오씨의 생태적 정착과 서식을 설명하는 경관언어가 분명하다. 장소성이 "어떤 실체로서 존재하기 보다는 담론과 실천에 의해 만들어지는 사회적 고안물이다"라는 정의를 상기할 때, 주변 지명과 용원정원림 그리고 마을 도처에 산재한 다수의 조영물은 한국적 장소성의 특성을 일목요연하게 보여주는 종족집단의 기념비적 장소 전승의 사례이다. 구화공이 고학리에 정착한 이래 해주오씨 종족집단은 서식지 정착단계를 거쳐 장소성 구현을 통한 경관형성단계를 이루었다. 이후 조상숭모와 장소착근 현상이 되풀이되면서 영역성은 확산되고, 장소의 재생산이 이루어졌다. 특히 일제강점기에도 재실 건립과 유허비 조성 등이 이어졌으며, 해방 이후에도 용원정 건립 등 장소재현의 단계를 거쳐 현재까지도 다양한 형태의 기념비적 종족경관이 펼쳐지고 있으며, 이러한 장소애착(場所愛着)과 장소착근(場所着根)의 결과가 바로 우리가 지각하는 '거창군 마리면 고학리의 종족경관'이라는 결론에 도달하게 된다. 종족집단의 장소애착과 장소착근의 현상이 되풀이되어 형성된 영역성 확산의 산물이야말로 종족경관의 실체인 것이다. 이를 통해 우리는 집단 기억 속에 재차 구축 전승되고 있는 고유한 장소에 대한 후손들의 진지한 관심과 사랑 그리고 진정한 장소애착의 정신을 확인하게 된다.

3G LTE and SAE

이현우,Lee Hyun-Woo 한국통신학회 2006 정보와 통신 Vol.23 No.6

순도에 따른 Al 판재의 재결정 거동

이현우,하태권,박형기,민석홍,Lee, Hyun Woo,Ha, Tae Kwon,Park, Hyung-Ki,Min, Seok-Hong 한국재료학회 2016 한국재료학회지 Vol.26 No.12

Recrystallization behavior has been investigated for commercial purity AA1050 (99.5wt%Al) and high purity 3N Al (99.9wt% Al). Samples were cold rolled with 90% of thickness reduction and were annealed isothermally at 290, 315, and 350o C for various times until complete recrystallization was achieved. Hardness measurement and Electron Backscatter Diffraction(EBSD) analyses, combined with Grain Orientation Spread(GOS), were employed to investigate the recrystallization behavior. EBSD analysis combined with GOS were distinctly revealed to be a more useful method to determine the recrystallization fraction and to characterize the recrystallization kinetics. As the annealing temperature increased, recrystallization in AA1050 accelerated more than that process did in Al 3N. Both AA1050 and Al 3N showed the same temperature dependence of the n value of the Johnson-Mehl-Avrami-Kolmogorov equation(JMAK equation), i.e., n values increased as annealing temperature increased. Activation energy of recrystallization in AA1050 is about 176 kJ/mol, which is comparable with the activation energy of grain boundary migration in cold-rolled AA1050. This value is somewhat higher than the activation energy of recrystallization in Al 3N.