센서 네트워크에서의 거리에 따른 동적 크기 다중홉 클러스터링 방법

안상현,임유진,Ahn, Sang-Hyun,Lim, Yu-Jin 한국정보처리학회 2007 정보처리학회논문지 C : 정보통신,정보보안 Vol.14 No.6

제한된 자원을 가진 센서 노드들로 구성된 센서 네트워크에서 가장 중요한 이슈 중 하나는 주어진 에너지를 최대한 활용하여 네트워크 수명을 연장하는 것이다. 네트워크 수명을 연장하는 가장 대표적인 방법은 클러스터링 방법이며, 이는 단일홉 모드와 다중홉 모드로 분류된다. 단일홉 모드는 클러스터 내의 모든 센서 노드들이 CH(Cluster Head)와 단일홉 통신을 하는 것을 말하며, 반면 다중홉 모드는 중간 노드들의 중계를 통하여 센서 노드와 CH가 통신하는 방식을 말한다. 기존의 다중홉 클러스터링 방식에서 성능 상 가장 중요한 영향을 미치는 요소는 클러스터 크기이며, 노드의 분포가 균일하다고 가정하였다. 그러나 실제 네트워크에서의 노드 분포는 균일하지 않을 수 있으므로 이러한 환경에서의 최적의 클러스터 크기 계산은 아주 어렵다. 본 논문에서는 싱크 주변의 CH에 대한 트래픽 부하를 줄이기 위하여 싱크로부터의 거리를 기반으로 클러스터 크기를 동적으로 변화시키는 다중홉 클러스터링 방법을 제안한다. 또한 수학적 분석과 시뮬레이션을 통하여 제안된 동적크기 클러스터링 방식이 기존의 고정크기 클러스터링 보다 더 나은 성능을 가짐을 보였다. One of the most important issues on the sensor network with resource limited sensor nodes is prolonging the network lifetime by effectively utilizing the limited node energy. The most representative mechanism to achieve a long lived sensor network is the clustering mechanism which can be further classified into the single hop mode and the multi hop mode. The single hop mode requires that all sensor nodes in a cluster communicate directly with the cluster head(CH) via single hop md, in the multi hop mode, sensor nodes communicate with the CH with the help of other Intermediate nodes. One of the most critical factors that impact on the performance of the existing multi hop clustering mechanism is the cluster size and, without the assumption on the uniform node distribution, finding out the best cluster size is intractable. Since sensor nodes in a real sensor network are distributed non uniformly, the fixed size mechanism may not work best for real sensor networks. Therefore, in this paper, we propose a new dynamic size multi hop clustering mechanism in which the cluster size is determined according to the distance from the sink to relieve the traffic passing through the CHs near the sink. We show that our proposed scheme outperforms the existing fixed size clustering mechanisms by carrying out numerical analysis and simulations.

차량 애드혹 네트워크에서 차량 자체 정보를 기반으로 한 클러스터링 기법

안상현,임유진,Ahn, Sang-Hyun,Lim, Yu-Jin 한국정보처리학회 2011 정보처리학회논문지 C : 정보통신,정보보안 Vol.18 No.6

차량 애드혹 네트워크 환경에서 브로드캐스트 메시지 전송을 위한 효율적인 기법으로 클러스터링 기법이 있다. 대부분의 클러스터링 기법들은 안정적인 클러스터 구성을 위해 차량들 간에 정보를 교환하거나 이동성 정보를 계산하는 오버헤드를 야기한다. 이러한 오버헤드를 줄이기 위해 차량의 절대 속도를 기반으로 클러스터를 구축하는 CF-IVC[1]가 제안되었으나, CF-IVC의 경우 도로 혼잡 상황이나 운전자의 운전 행태를 고려하지 않음으로써 클러스터를 비효율적으로 구성하는 문제가 있다. 따라서 본 논문에서는 도로의 최고 제한 속도 및 도로 혼잡 상황을 고려한 차량 자체 정보 기반의 효율적인 클러스터 구축 기법을 제안한다. 제안 방식을 simple 플러딩 및 CF-IVC와 NS-2 시뮬레이션을 통해 비교함으로써 성능의 우수성을 입증한다. In the vehicular ad hoc network environment, the clustering mechanism is one of the efficient mechanisms to deliver broadcast messages. Most clustering mechanisms require message exchanges between vehicles to build stable clusters, which causes overhead. In order to reduce this overhead, CF-IVC [1] proposes the mechanism to construct clusters based on the vehicle speed. However, since CF-IVC does not consider the road traffic condition and the driver's behavior, it may result in inefficient clusters. Therefore, in this paper, we propose a mechanism to establish efficient clusters based on the vehicle local information with considering the road maximum speed limit and the road traffic condition. The performance of the proposed mechanism is validated by comparing with those of the simple flooding and CF-IVC through NS-2 simulations.

강 슬리브 파단 직선 슬리브의 장력 및 열적 특성 분석 연구

안상현,김병걸,김상수,손홍관,박인표,김성규,Ahn, Sang-Hyun,Kim, Byung-Geol,Kim, Sang-Shu,Sohn, Hong-Kwan,Kim, In-Pyo,Kim, Sung-Kyu 한국전기전자재료학회 2008 전기전자재료학회논문지 Vol.21 No.11

According to previous report, aged sleeves of old transmission line showed several defaulted installation patterns, which was biased or corrosive-fractured of steel sleeve installed cases. These defects can cause serious accidents such as rapid increasing of sag or falling out of overhead conductor from sleeves. Consequently, the defects lead to the major power outage. Corrosion of steel sleeve is a typical defect by aging of sleeves. And it occupied almost 25 percent of investigated aged sleeves. This paper studied thermal properties and tension for ACSR conductor in case of fractured steel sleeve model by corrosion. The temperature distribution within overhead conductor has a specific gradient. Thermal properties of splice connectors(sleeve and clamp) showed normal behavior. However, mechanical properties were worse than normal sleeves. The detailed results were presented in the text.

PKC 활성 조절을 통한 두시 하태독법의 항염증작용이 Mite 항원 유도 아토피유사피부염 발병 조절에 미치는 효과

안상현,김기봉,Ahn, Sang Hyun,Kim, Ki Bong 대한한방소아과학회 2016 대한한방소아과학회지 Vol.30 No.4

Objectives Hataedock (HTD) is an oral Korean herbal medical oral treatment that removes fetal toxic heat and meconium from new born babies. The purpose of this study is to evaluate whether Hataedock treatment of Duchi extracts has anti-inflammation effects in atopic dermatitis-like skin lesions in House Dust Mite-Induced NC/Nga Mice. Methods The mice were divided into 3 groups (n=10 per group) as follows: the control group (Ctrl group), AD-induced group (AE group), AD-induced with HTD treatment group (DT group). 3-week-old NC/Nga mice were introduced to Hataedock treatment, made of Duchi extract. After 4 weeks, House Dust Mite-Induced application was used six times per week for 3 weeks to induce the first atopic dermatitis, and second AD in 7 weeks after. To examine skin injuries and anti-inflammatory effect, PKC, MMP-9, iNOS immunohistochemistry were used. Results The alleviate effect of the skin damage and angiogenesis was observed in DT group. The damage of stratum corneum, hyperplasia, edema, infiltration of lymphocytes and distribution of capillary were decreased in DT group. Also, the study results suggested that Hataedock treatment made of Duchi extracts in DT group remarkably decreased skin damages by 51% (p < 0.001), as well as PKC by 91%, MMP-9 by 48% (p < 0.001), iNOS by 51% (p < 0.001). Conclusions Based on the study results, we observed that Hataedock treatment of Duchi extracts alleviates AD by diminishing various inflammatory cytokines, initial steps of AD development, in the skin lesions. Potential applications for prevention and treatment of atopic dermatitis are expected.

인산형 연료전지의 가스확산전극의 구조개선과 전기화학적 특성평가

안상현,심재철,유덕영,김인,이주성 ( Sang Hyun Ahn,Jae Cheol Shim,Duck Young Yoo,In Kim,Ju Seong Lee ) 한국공업화학회 1997 한국공업화학회 연구논문 초록집 Vol.1997 No.0

두시 하태독법의 IL-4 활성 조절이 D. farinae 유도 아토피유사피부염 발병 조절에 미치는 효과

안상현,김재규,천진홍,김기봉,Ahn, Sang Hyun,Kim, Jae Kyu,Cheon, Jin Hong,Kim, Ki Bong 대한한방소아과학회 2017 대한한방소아과학회지 Vol.31 No.1

Objectives Hataedock method is a Korean medical therapy which removes fetal toxin by orally administering herbal decoction to neonates. This study was to observe skin damage and anti-inflammatory effect via regulating IL-4 activity in NC/Nga mice which were induced atopic dermatitis (AD)-like skin lesion by Dermatophagoides (D.) farinae after applying Douchi Hataedock method. Methods NC/Nga mice with 3 weeks of gestational age were used. Each 10 mice were allocated to the control group (Ctrl), the AD-induced group (AE), and the group which induced AD after administering Douchi extract (GT). After 4 weeks from administering Douchi extract to the mice, the primary AD was induced by applying D. farinae extract 6 times per week for 3 weeks and then the secondary AD was induced by the same method after 1 week from the primary AD induction. To identify the skin damage and anti-inflammatory effect, we observed LxR, IL-4, Fc ${\varepsilon}$ receptor, substance P, and $NF-{\kappa}B$. Results The GT group showed alleviation of skin injury and decrease in capillary angiogenesis. Stratum corneum damage, epithelial cell hyperplasia, lymphocyte infiltration, and capillary distribution relatively decreased in the GT group. LxR-positive reaction in the GT group were increased by 53% than that of the AE group. IL-4 production, $Fc{\varepsilon}$ receptor activity, and substance P-positive reaction in the GT group were decreased by 82%, 42%, and 82% respectively compare to those of the AE group. $NF-{\kappa}B$-positive reaction in the GT group were decreased by 15% compare to that of the AE group. Conclusions Hataedock method with Douchi extract alleviated AD via reducing inflammatory cytokines secreted at the early stage of AD. Thus, Douchi Hataedock method has a beneficial effect for the prevention and treatment of AD.

두시 하태독법이 시행된 비만 생쥐에서 Th2 분화조절을 통한 알러지성 비염 유발 감소 효과

안상현,김기봉,Ahn, Sang Hyun,Kim, Ki Bong 대한한방소아과학회 2018 대한한방소아과학회지 Vol.32 No.2

Objectives This study investigated the effects of Hataedock treatment with Douchi on induction of allergic rhinitis in obese induced NC/Nga mice. Methods NC/Nga mice were divided into control group (Ctrl), allergic rhinitis induced obese mice group (ARE), and allergic rhinitis induced obese mice group with Douchi Hataedock treatment (FGT). The 3-week-old mice of the FGT group were given one 10 mg/kg dose of Douchi Hataedock extract and sensitized with allergic antigens at weeks 4, 5, and 6. After 1 week of final sensitization, allergic rhinitis was induced primarily in mice nasal cavities for five days. After one week of the completion with the first induction, the second induction was introduced by the same method. After 1 week, few samples of the nasal mucosal tissues of each group were prepared. The factor of Th2 differentiation and inflammation control such that IL-4, STAT6, CD40, $Fc{\varepsilon}RI$, substance P, MMP-9, $NF-{\kappa}B$ p65, p-IkB, iNOS and COX-2 were observed by immunohistochemistry. Also, the difference in nasal mucosal injury was observed by histochemical method (PAS staining). Results The FGT group showed that reduced IL-4 production, STAT6 expression and CD40 expression by regulating excessive Th2 differentiation. Also, production of substance P and MMP-9 and activity of $Fc{\varepsilon}RI$ in mast cells were decreased. Inhibition of $NF-{\kappa}B$ p65 activity was induced by inhibition of p-IkB, and the production of inflammatory enzymes iNOS and COX-2 were decreased. In addition, the damage of intramural respiratory epithelium was low and excessive mucin secretion in goblet cells was low. Conclusions This study confirmed the possibility of controlling the allergic rhinitis in obese children who are expected to have an overactive inflammation.

백호탕 추출물의 지방장벽 손상 개선을 통한 상피 내 Th2 분화 조절 효과

안상현,김기봉,정아람,Ahn, Sang Hyun,Kim, Ki Bong,Jeong, Aram 대한한방소아과학회 2021 대한한방소아과학회지 Vol.35 No.4

Objectives The purpose of this study is to confirm the regulate effect of T helper (Th) 2 differentiation that Baekho-tang extract may produce to improves skin lipid barrier damages. Methods Four-weeks-old NC/Nga mice were divided into four groups: control group (Ctrl, n=10), lipid barrier eliminated group (LBE, n=10), Dexamethasone treatment after lipid barrier elimination group (DxT, n=10), and Baekho-tang extract treatment group after lipid barrier elimination group (BHTT, n=10). Baeko-tang extract was administered for 3 days after removal of the skin fat barrier in BHTT group. Then, we identified changes in external symptoms of the skin, factors affecting skin barrier such as potential of hydrogen (pH), filaggrin (FLG), transepidermal water loss (TEWL) and Th2 differentiation factors like Interleukin (IL)-4, Kallikrein Related Peptidase 7 (KLK7) and protease activated receptor 2 (PAR-2) through our immunohistochemistry. Results After lipid barrier elimination, the reduction of morphological skin inflammations was less in BHTT group than in LBE group and DxT group. Also, pH and TEWL were significantly decreased with BHTT group. However, FLG was significantly increased in BHTT group compared to LBE, DxT, and Ctrl group. All kinds of Th2 differentiation factors (IL-4, KLK7 and PAR-2) were also decreased in BHTT compared to the LBE and DxT. Conclusions As a result of this study, BHT administration decreased pH, TEWL, and increased FLG, thus participating in recovering damaged skin barrier. Since Th2 differentiation factors were decreased as well, BHT's regulatory effect in sequential immune reactions may be a possible explanation of how it enhances recovery of the damaged lipid barrier.

포스터 발표 - 무기재료분과 / 전기화학분과 / 촉매분과 : 인산형 연료전지의 가스확산전극의 구조개선과 전기화학적 특성평가

안상현,심재철,유덕영,김인,이주성 ( Sang Hyun Ahn,Jae Cheol Shim,Duck Young Yoo,In Kim,Ju Seong Lee ) 한국공업화학회 1997 한국공업화학회 연구논문 초록집 Vol.1990 No.3

MANET 환경에서 주소 영역기반 주소할당 분산기법

안상현,임유진,유현,Ahn, Sang-Hyun,Lim, Yu-Jin,Yu, Hyun 한국정보처리학회 2009 정보처리학회논문지 C : 정보통신,정보보안 Vol.16 No.6

시간과 장소에 상관없이 인터넷 서비스를 제공 받고자 하는 인터넷 사용자들의 요구가 증가함에 따라 MANET(Mobile Ad-Hoc Network) 환경에서도 인터넷 연결성을 제공하기 위한 연구들이 주목을 받고 있다. 기존 DHCP(Dynamic Host Configuration Protocol) 기반 방식의 경우는 망 내 노드들에게 주소를 할당하기 위하여 다중 홉 거리에 있는 DHCP 서버와 메시지를 교환해야 하기 때문에 메시지 손실이 쉽게 발생할 수 있으며, 이로 인해 주소 설정의 안정성이 감소하고 주소 설정 시간이 증가하는 문제점이 있다. 따라서 본 논문에서는 노드가 DHCP 서버로부터 하나의 주소만을 할당 받는 것이 아니라 일정 크기의 주소 영역을 할당 받을 수 있게 하였다. 또한 주소 영역을 할당 받은 노드가 이웃의 주소 요청 노드들에게 자신의 주소 영역 중 일부를 할당할 수 있도록 하는 새로운 주소 설정 기법을 제안하였다. 모의 실험을 통하여 제안 기법이 기존 DHCP 기법에 비하여 주소 설정 시간과 제어 메시지 수 측면에서 각기 77%와 61%의 성능을 향상시킬 수 있음을 보였다. As it becomes increasingly important that Internet access is available anywhere at any time, providing MANET (Mobile Ad-Hoc Network) with the Internet access attracts more attention. The existing DHCP (Dynamic Host Configuration Protocol) address configuration schemes require message exchanges between MANET nodes and the DHCP server through multi-hop routes. Messages can be easily dropped in the wireless multi-hop communication environment and the address configuration may be instable and need long delay. In this paper, we propose a new address configuration scheme using the concept of address pool allocation. In the proposed scheme, the DHCP server assigns a part of its address pool to a node instead of a single address and the node can assign a part of its own address pool to its neighbor nodes. Through simulation studies, we show that our scheme yields about 77% of the address configuration delay and 61% of the control message overhead of the existing DHCP based mechanism.