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      • 방조제 개방구간의 투하 석재와 돌망태 안정성 수리시험 연구

        박상현,Park Sang-hyun 한국관개배수위원회 1997 한국관개배수논문집 Vol.4 No.2

        In the final stage of seadike closing, the flow in the tidal gap changes rapidly to high accelerating flow, causing losses of construction materials. As the tidal velocity through the gap of an end dump contraction is highly nonuniform, flow equations on

      • KCI등재후보

        법랑기질유도체를 도포한 타이태늄 표면에서 조골세포의 증식 및 분화

        박상현,이인경,양승민,신승윤,이용무,구영,류인철,정종평,한수부,최상묵,Park, Sang-Hyun,Lee, In-Kyeong,Yang, Seung-Min,Shin, Seung-Yun,Lee, Yong-Moo,Ku, Young,Rhyu, In-Chul,Chung, Chong-Pyoung,Han, Soo-Boo,Choi, Sang-Mook 대한치주과학회 2003 Journal of Periodontal & Implant Science Vol.33 No.3

        Among objectives of periodontal therapy. the principal one is the morphological and functional reconstruction of lost periodontal supporting tissues. This includes de novo formation of connective tissue attachment and the regrowth of alveolar bone. The use of enamel matrix derivative(EMD) may be a suitable means of regeneration new periodontal attachment in the infrabony defects. Implant used to replace lost tooth but, implantitis occurred after installation. The purpose of this study was to investigate the effects of EMD on differentiation and growth of osteoblast in titanium disc. Twentyfive millimeter diameter and 1mm thick Ti disc which was coated 25, 50, 100, 200${\mu}g$/ml of EMD(Emdogain(R)) used as experimental group, 25, 50, 100, 200ng/d of rhBMP-2 as positive control group, and no coat as negative control group. A human osteosarcoma cell line Saos-2 was cultured in Ti disc and cell proliferation and Alkaline phosphatase (ALP) activity were measured at 1 and 6 days. PCR was performed at 2 and 8 hours. Semi-quantitative RT-PCR for mRNA expressions of various osteoblastic differentiation markers -type I collagen, ALP, osteopontin, and bone sialoprotein - were performed at appropriate concentrations based upon the results of MTT and ALP assay. Cultured cell-disc complexes were prepared for scanning electron microscopy (SEM) at 2 hour. Data were analyzed using Mann-Whitney and repeated- measures 1-way analysis of variance(SPSS software version 10,SPSS. Chicago. IL). After culture, there was more osteoblast in EMD100${\mu}g$/ml than in EMD50, 200${\mu}g$/ml on day 6. There was significant difference in experimental and positive control group compared control group, as times go by(1 and 6 days). Alkaline phosphatase activity was different significantly in EMD100, 200${\mu}g$/ml and BMP100, 200${\mu}g$/ml on day 6. The results of reverse transcriptase-polymerase chain reaction (RT-PCR) showed that expression of mRNA for ALPase, collagen type I, osteopontin. hone sialoprotein and BMP-2 was detected at 2 hour and 8 hour in EMI 200${\mu}g$/ml subgroup and BMP100ng/ml subgroup. The results of this study suggest that application of enamel matrix derivative on osteoblast attached to titanium surface facilitate the expression of bone specific protein and the differentiation and growth of osteoblast.

      • KCI등재

        Long-term impacts of Argentine ant invasion of urban parks in Hiroshima, Japan

        박상현,Shingo Hosoishi,Kazuo Ogata 한국생태학회 2014 Journal of Ecology and Environment Vol.37 No.3

        Ant communities are well suited for monitoring changes in ecosystems. Although numerous studies have examined the responses of ant communities to environmental disturbance, relatively few long-term studies on ant communities have been undertaken in urban environments. We examined species richness in nine urban parks in Hiroshima, Japan, and compared the survey results with data collected at the same sites using the same methods in 1999. In both surveys, total of 25 species was recorded: 23 species in 1999 and 20 species in 2012. Non-metric multidimensional scaling analysis revealed that the ant communities consisted of two distinct groups, which could in turn be characterized by three patterns of ant community changes in between the two groups. The first of these community change patterns was characterized by a shift within group 1, but the number of species remaining constant (approx. 10 species). The second pattern was characterized by a shift within group 2, but the number of species remained low (approx. 4 species). The third pattern was characterized by a shift from group 1 to group 2 as the abundance of Linepithema humile (Mayr) increased over time. Unlike the first and second patterns, the number of ant species in communities of the third type decreased significantly. These findings suggest that L. humile has a marked effect on the species diversity of indigenous ant communities in urban environments.

      • SCIESCOPUSKCI등재

        우로수데옥시콜릭산이 치주질환 억제에 미치는 영향

        박상현,한승민,최상목,구영,류인철,한수부,이학모,김문무,김상년,정종평,Park, Sang-Hyun,Han, Seoung-Min,Choi, Sang-Mook,Ku, Young,Rhyu, In-Chul,Han, Soo-Boo,Lee, Hak-Mo,Kim, Moon-Moo,Kim, Sang-Nyun,Chung, Chong-Pyoung 대한치주과학회 1999 Journal of Periodontal & Implant Science Vol.29 No.1

        Ursodeoxycholic acid(UDCA) is a hydrophilic gall bladder acid and has been used as a effective drug for liver disease related to in1munity. This drug inhibits secretions of IL-2, IL-4, and $IFN-{\gamma}$ from T-cells and production of immunoglobulin from B-cells. Also it has been reported that UDCA inhibits production of IL-1 related to the progression of periodontal disease and activation of collagenases. The purpose of the present study was to elucidate the effects of UDCA on inhibition of periodontal disease progression using clinical, microbiological and histometrical parameters. Twelve pure bred, 16 month-old-beagle dogs were used in the study. After ligature-induced periodontal diseases were formed, experimental drugs were applied twice a day and then the results of clinical, microbiological, and histometrical parameters were measured at baselie(initiation of experiment) , 4weeks and 8weeks. The gel with UDCA(concentration 0.5%, 5% 3 dogs in each) was applied to experimental group, chlorhexidine to positive control group(3dogs) and the gel without UDCA(base) to negative control group. After induction of general anesthesia, the maxillary 2nd, 3rd premolars and 1st molar and the mandibular 2nd, 3rd, 4th premolars and 1st molar were ligated in one side selected randomly and were not ligated in the opposite side. The plaque index(PI), gingival index(GI), pocket depth(PD) and gingival crevicular fluid(GCF) volum were measured clinically. The PI and GI were measured at 3 buccal points of all experimental teeth and the GCF was measured only at the 3rd premolar in the maxilla and the 4th premolar in the mandible. In the microbiological study, the samples extracted from the 3rd premolar of the maxilla and the 4th premolar of the mandible at the center of buccal surface were analyzed aerobics, anaerobics and Streptococcus colony forming units, After clinical and microbiological examination at 8weeks, the dogs were sacrificed by carotid artery perfusion. The samples were fixed and sectioned including interproximal area, and the distance from cementoenamel junction(CEJ) to alveolar crest was measured. The results were that PI, GI and PD increased until 4 weeks and decreased at 8 weeks in three groups but the differences between all the groups were not significant. The 0.5% UDCA in non-ligated group showed remarkable decrease of GCF. The experimental group applied 5% UDCA decreased the number of aerobics and anaerobics. The distance from CEJ to alveolar crest was greater in the negative control group on both ligated and non-ligated sides, but the differences were not significant stastically.

      • 타임스탬프를 갖는 이벤트 시퀀스를 위한 인덱스 기반 검색 기법

        박상현,원정임,윤지희,김상욱 한국정보과학회 2004 데이타베이스 연구 Vol.20 No.2

        본 논문에서는 타임스탬프를 갖는 이벤트 시퀀스를 위한 유사 서브시퀀스 매칭 문제에 관하여 논의한다. 먼저, 첫 이벤트와 이후의 이벤트의 발생 간격의 허용치를 범위의 형태로서 제시하는 방식의 실용적인 새 질의 모델을 제시한다. 또한, 기존의 Iso-Depth 인덱스를 이용하여 이러한 질의 모델을 지원하는 경우, (1) 허용치의 범위에 비례하는 성능 저하의 문제와 (2) 동적 환경으로 적응하는 데에 따르는 문제가 발생함을 지적한다. 그 다음, 이러한 두 가지 문제점들이 Iso-Depth 인덱스의 구조적 특성으로 인한 것임을 밝히고, 이를 다차원 인덱스로 대치하는 새로운 기법을 제안한다. 제안된 기법이 질의를 만족하는 모든 서브시퀀스들을 착오 기각 없이 모두 찾아 낼 수 있음을 이론적 과정에 의하여 증명한다. 또한 발생 가능한 이벤트 유형의 수가 많은 경우에 발생할 수 있는 차원의 저주 문제를 해결하기 위하여 이벤트 유형의 그루핑을 통하여 차원을 축소하는 방안을 제시한다. 다양한 실험에 의한 기존 기법들과의 성능 비교를 통하여 제안된 기법의 우수성을 규명한다. 실험 결과에 의하면, 제안된 기법은 순차 검색 및 Iso-Depth 인덱스를 기반으로 하는 기존의 기법에 비하여 수배에서 수십배의 성능 개선 효과를 보이는 것으로 나타났다.

      • KCI등재

        알루미늄 5083 합금의 플라즈마 미그 하이브리드 용접시 용접부 미세조직과 기계적 성질 변화에 미치는 용접조건의 영향

        박상현,이희근,김진용,정하택,박영환,강정윤,Park, Sang-Hyeon,Lee, Hee-Keun,Kim, Jin-Young,Chung, Ha-Taek,Park, Young-Whan,Kang, Chung-Yun 대한용접접합학회 2015 대한용접·접합학회지 Vol.33 No.1

        The effect of welding condition on microstructure and mechanical property of Plasma-MIG Hybrid Weld between Al 5083 plates(thickness : 10mm) was investigated. 1 pass weld without any defects such as puckering, undercut, and lack of fusion was obtained by 150~200A of plasma current and 5~7mm of welding speed. Gas porosities and shrinkage porosities were existed in the weld near fusion line. As welding speed and plasma current were decreasing, the area fraction of porosity was increasing. The hardness of the weld is increasing as welding speed. On the basis of microstructural analysis, Mg segregated region near dendrite boundaries tends to increase with the welding speed. In the result of hardness test, Distribution of hardness in fusion zone showed little change with the plasma current. However, when the welding speed increased, hardness in weld metal markdly increased. It could be considered that effect of heat input to growth of the dendritic solidification structures. Based on tensile test, tensile properties of weld metal was predominated by area fraction of porosities. Consequently, tensile properties can be controlled by formation site and area fraction of porosity.

      • DGNSS 서비스를 위한 국제표준 분석과 전망

        박상현,서기열 한국항해항만학회 2013 한국항해항만학회 학술대회논문집 Vol.2013 No.추계

        '스콜라' 이용 시 소속기관이 구독 중이 아닌 경우, 오후 4시부터 익일 오전 7시까지 원문보기가 가능합니다.

        보다 편리하고 안전한 항해를 위해 GPS 뿐만 아니라 GLONASS 등 다양한 위성항법시스템이 항해장비 및 통신장비에 이용되고 있다. 특히 항만을 포함한 연안에서는 위성항법시스템 단독으로 제공하는 위치 항법 시각정보 보다 더 정확하고 신뢰할 수 있는 정보를 얻기 위해 보강시스템 개념의 DGPS 서비스를 제공하고 있다. 위성항법시스템의 다원화는 현재 연근해는 물론이고 육상에서도 제공하고 있는 DGPS 서비스를 DGNSS 서비스로 확장해야 하는 필요를 낳았다. 본 논문은 현재 국제기구가 제정한 기술표준과 권고서를 분석하고, 이들이 가지고 있는 다원화의 한계성과 유연성, 확장성의 부족을 제시한다. 그리고 현재 논의되고 있는 차세대 DGNSS 관련 국제표준과 제시한 문제와의 상관관계를 보인다. 마지막으로 본 논문은 DGNSS 서비스를 위한 국제표준의 변화가 미치게 될 영향에 대해 전망한다.

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