• 제목/요약/키워드: happens before

검색결과 80건 처리시간 0.02초

스팀터빈 발전기 진동진단 시스템 개발 (Development of a Vibration Diagnostic System for Steam Turbine Generators)

  • 이안성;홍성욱;김호종;이현
    • 소음진동
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    • 제5권4호
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    • pp.543-553
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    • 1995
  • Modern steam turbine generators are being built as a higher power and larger system, experiencing more frequent starts and stops of operation due to a constant change of power demands. Hence, they are inevitably more vulnerable to various vibrations, and more often exposed to the danger of sudden vibration accidents than ever before. Even under the circumstances, in order to secure the system reliability of steampower plants and there by to supply safely the public electricity, it is important to prevent a sudden vibration accident in one hand and even when it happens, to raise an operating efficiency of the plants throught swift and precise treatments in the other. In this study, an interactive vibration diagnostic system has been developed to make the on-site vibration diagnosis of steam turbine generators possible and convenient, utilizing a note-book PC. For this purpose, at first the principal vibration phenomena, such as various unbalance and unstable vibrations as well as rubbing, misalignment, and shaft crack vibrations, have been systematically classified as grouped parameters of vibration frequencies, amplitudes, phases, rotating speeds at the time of accident, and operating conditions or condition changes. A new complex vibration diagnostic table has been constructed from the causal relations between the characteristic parameters and the principal vibration phenomena. Then, the diagnostic system has been developed to screen and issue the corresponding vibration phenomena by assigning to each user-selected combination of characteristic parameters a unique characteristic vector and comparing this vector with a diagnostic vector of each vibration phenomenon based on the constructed diagnostic table. Moreover, the diagnostic system has a logic whose diagnosis may be performed successfully by inputing only some of the corresponding characteristic parameters without having to input all the parameters. The developed diagnostic system has been applied to perform the diagnosis of several real cases of steam turbine vibration accidents. And the results have been quite satisfactory.

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CT 영상을 이용한 3D 프린팅으로 환자 맞춤형 대퇴골 첨삭가공 (Additive Manufacturing of Patient-specific Femur Via 3D Printer Using Computed Tomography Images)

  • 오왕균;임기선;이태수
    • 한국방사선학회논문지
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    • 제7권5호
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    • pp.359-364
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    • 2013
  • 대퇴골은 사람의 뼈 중 가장 길며 체중을 지탱하는 골격체로 대퇴골간은 긴 파이프 모양이면서 안에 해면골이 거의 없어서 골절이 발생되면 재생이 어렵다. 사고로 인하여 발생되는 대퇴골의 골절은 골간부가 가장 높은 빈도로 발생한다. 골절의 수술방법은 골수강에 IM Nail을 삽입하여 골절부위를 고정하는 IM Nailing이다. 수술 시 대퇴골의 중심으로 진입하지 못하면 2차 골절 등의 피해가 발생하기도 한다. 본 연구에서는 수술 전 대퇴골의 CT IMAGE을 이용하여 3D 프린터로 환자 맞춤형 대퇴골을 제작하여 골수강으로 IM Nailing 시뮬레이션을 할 수 있도록 하였다. 수술 중 발생할 수 있는 2차적 손상을 방지 하고 시간 단축, 정밀한 수술을 할 수 있을 것이다.

거주와 건립에 관한 한 고찰 (A Study on Dwelling and Building)

  • 강혁
    • 건축역사연구
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    • 제11권4호
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    • pp.71-86
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    • 2002
  • Since Modern period which is characterized by the governing of technology and capitalism, the production and aesthetics of building became a main issue of architectural discourse. Morever, Modern architecture tends to be a kind of media in which the visual image of building plays a far more important role than building itself. Institutionalized discipline of Architecture in modern system set aside the dwelling aspect of building and destructed close relationship between dwelling and building. This study analyzes the essential meaning of dwelling with a viewpoint of building and vise virsa in order to have a deep reflection on contemporary architecture and modern crisis of dwelling. For this purpose this study first reviewed linguistic and mythical narratives on the origin of dwelling and building. Secondly, reviewed the thought of Heidegger on dwelling and building and his thinking on authenticity of dwelling. Thirdly, reviewed drastic change of idea and reality of dwelling recent days, especially from settlement to nomad. Lastly reviewed E. Levinas' thinking on bodily dwelling or primordial mode of dwelling before poetic dwelling of Heidegger. With these review we can figure out following things on dwelling and building. Physical building or its visual image can not take the place of dwelling in itself. Dwelling and Building happens simultaneously and understood as an event in life world. Today's alienation of dwelling from building reduced our conception of architecture to a physical setting and mere technique. Building must be a ontological and cultural phenomenon beyond physical building. Nomad in this age of information and globalization may be a new mode of dwelling. But it can not exclude traditional way of dwelling on concrete space, because human being as a physical being can not abandon dwelling place that gives a primordial comfort with and within our body.

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퍼지 및 지능적 PLC에 의한 실시간 교통상황 예보 시스템 (Forecasting of Real Time Traffic Situation by Fuzzy and Intelligent Software Programmable Logic Controller)

  • 홍유식;조영임
    • 전자공학회논문지CI
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    • 제41권4호
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    • pp.73-83
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    • 2004
  • 제한된 도로에서 증가되는 차량으로 인해서, 평균주행속도가 떨어지고 교차로의 대기 손실이 많아지고 있다. 본 논문은 10개 교차로를 연동 제어를 할 수 있는 새로운 교통체제 개념을 제안한다. 예를 들어서 오늘 야구경기가 8시경에 열린다고 하면 야구경기가 시작하기 전 1시간 혹은 1시간 30분전에 교통량이 증가할 것이다. 이럴 때에는 아무리 우수한 전자 신호등 시스템도 최적녹색시간을 예측할 수 없다. 그러므로 본 논문에서는 평균 승용차 대기시간을 최소화하고 평균 주행속도를 향상하기 위해서 전처리로써 퍼지규칙 및 신경망을 이용한다. 또한 후처리로써 예기치 못한 상황을 지능적으로 제어할 수 있는 지능적인 소프트웨어 PLC(Programmable Logic Controller)를 구현하였다. 시뮬레이션결과 제안된 연동 녹색시간이 연동 녹색시간을 고려하지 않은 전자신호등보다 평균 승용차 대기시간을 줄일 수 있음을 입증했다.

Levels of Depression and Anxiety Post-Mastectomy in Breast Cancer Patients at a Public Sector Hospital in Karachi

  • Khan, Sara;Khan, Naveed Ali;Rehman, Ata Ur;Khan, Iqra;Samo, Khursheed A;Memon, Amjad Siraj
    • Asian Pacific Journal of Cancer Prevention
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    • 제17권3호
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    • pp.1337-1340
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    • 2016
  • Background: There is a noticeable change in the approach with which women nowadays seek help for diseases like breast cancer, primarily due to awareness campaigns, but what happens after surgical procedures is of great significance too. This study focused on the several psychological connotations attached to mastectomy and how the patients cope. Objective: To understand the pattern of anxiety and level of depression among Pakistani patients undergoing mastectomy. Materials and Methods: The sample size consisted of 88 patients who had undergone mastectomy at the different surgical units of the Civil Hospital, Karachi, from January 2012-December 2014; The questionnaire was administered before they were discharged i.e. within 3 days of surgical procedures. The patients were asked if they were willing to participate in this study, those who agreed signed the consent form and then we preceded by asking questions with a standardized tool. A self made questionnaire was constructed keeping in mind the nature and specification of the disease, which consisted of 20 questions related to anxiety and depression, focusing on a mixture of psychological and physiological symptoms. Results: There were a total of 88 patients out of which 36 (41%) were aged 51 to 60 years, 24 (27.2%) of the patients were in the age category of 41 to 50 years, 17 aged 61 and above (19.3%) and only 11 (12.5%) 30-40 years of age, the youngest of all the age categories. The pattern of depression and anxiety was found to be similar among all age categories, severe depression and anxiety predominating over moderate level of such symptoms, with only relatively few patients sufering mild or no depression symptoms. Conclusions: It was concluded that going through mastectomy leads to moderate to severe levels of depression and anxiety, primarily because the females feel incomplete and insecure after losing a part of themselves.

자한(自汗)과 도한(盜汗)의 기전에 대한 고찰 -역대 의서의 논설을 중심으로- (A Study on the Mechanism of Spontaneous Sweating(自汗) and Night Sweating(盜汗) -Focusing on Discussions in Classical Medical Texts-)

  • 윤기령
    • 대한한의학원전학회지
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    • 제33권3호
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    • pp.111-133
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    • 2020
  • Objectives : The aim of this paper is to examine the mechanisms of spontaneous sweating and night sweating, their relationship and how the explanations of their mechanisms have changed over the course of time, through examination of past discussions on spontaneous sweating and night sweating. Methods : Contents in classical medical texts that mention the mechanisms of spontaneous sweating and night sweating among search results from databases such as the Siku Quanshu were analyzed, followed by examination of each of their mechanisms, and their relationship with each other. Results & Conclusions : The cause of night sweating before the 『Danxixinfa』 was seen to be caused by yang deficiency in relation to problems of Exterior Qi and the theory of 'Heart governs perspiration', as the focus was on the phenomenon of sweating. However, it seems that yin deficiency came to be seen as playing a more fundamental role in the process of determining the root cause of night sweating. Moreover, Zhu Danxi's emphasis on nurturing yin, the composition of Dangguiliuhuangtang, and the development of the fire-heat pathology since the Jin Yuan period added to this shift in perspective. Night sweating from Shanghan could be seen as a sign of the already damaged Exterior Qi becoming more deficient while the pathogenic qi is in the half-exterior-half-interior zone, or as the pathogenic qi which entered with the Exterior Qi unsettling yin, or as a result of heat that is produced in the struggle between healthy qi and pathogenic qi that happens when Exterior Qi enters. Night sweating from miscellaneous disease could be seen as a sign of a deficient exterior that resulted from excessive entering of the Exterior Qi during yin deficiency, or resulting from relatively excessive Exterior Qi to deficient yin, producing heat that leads to sweating. If yin is not cultivated during the night but rather consumed leading to deficiency of Exterior Qi which also needs to be cultivated during night time, it could result in sweating.

동아시아 지역의 AOGCM 불확실성 평가 및 미래기후전망 (An Uncertainty Assessment of AOGCM and Future Projection over East Asia)

  • 김민지;신진호;이효신;권원태
    • 대기
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    • 제18권4호
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    • pp.507-524
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    • 2008
  • In this paper, future climate changes over East Asia($20^{\circ}{\sim}50^{\circ}N$, $100^{\circ}{\sim}150^{\circ}E$) are projected by anthropogenic forcing of greenhouse gases and aerosols using coupled atmosphere-ocean general circulation model (AOGCM) simulations based on Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) B1, A1B and A2 scenarios. Before projection future climate, model performance is assessed by the $20^{th}$ Century (20C3M) experiment with bias, root Mean Square Error (RMSE), ratio of standard deviation, Taylor diagram analysis. The result of examination of the seasonal uncertainty of T2m and PCP shows that cold bias, lowered than that of observation, of T2m and wet bias, larger than that of observation, of PCP are found over East Asia. The largest wet bias is found in winter and the largest cold bias is found in summer. The RMSE of temperature in the annual mean increases and this trend happens in winter, too. That is, higher resolution model shows generally better performances in simulation T2m and PCP. Based on IPCC SRES scenarios, East Asia will experience warmer and wetter climate in the coming $21^{st}$ century. It is predict the T2m increase in East Asia is larger than global mean temperature. As the latitude goes high, the warming over the continents of East Asia showed much more increase than that over the ocean. An enhanced land-sea contrast is proposed as a possible mechanism of the intensified Asian summer monsoon. But, the inter-model variability in PCP changes is large.

저이동성을 갖는 무선 애드혹 망에서 다중 경로 정보를 이용한 에너지 인지 라우팅 프로토콜 (Energy-aware Routing Protocol using Multi-route Information in Wireless Ad-hoc Networks with Low Mobility)

  • 홍윤식
    • 한국콘텐츠학회논문지
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    • 제10권4호
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    • pp.55-65
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    • 2010
  • 낮은 이동성을 갖는 무선 애드혹 네트워크에서, 에너지 고갈에 따른 링크 단절 없이 네트워크 생존시간을 오랫동안 유지할 수 있는 방안을 제시한다. 일반적으로 에너지 잔량이 많이 남아 있는 노드는 트래픽 부하가 적은 노드이다. 따라서 노드의 에너지 잔량을 기준으로 경로를 결정하는 수정 AODV 라우팅 프로토콜을 제안한다. 한편, 기존 AODV에서는 경로 설정을 위해 엄청난 개수의 제어 패킷을 네트워크에 방송함으로써 전체 노드의 에너지 소비가 급격히 늘어난다. 이러한 제어 패킷을 효과적으로 줄이기 위해 발신지 노드는 대체 경로 정보를 자신의 경로 테이블에 저장하도록 하였다. 링크 단절이 발생했을 때, 경로 재설정을 시도하기 전에 발신지 노드는 경로 테이블에 저장된 대체 경로 중에서 해당 경로의 에너지 잔량 총합이 가장 큰 경로를 선택한다. 이렇게 함으로써 불필요한 AODV 제어 패킷 발생 가능성을 줄일 수 있다. 본 논문에서 제안한 방식을 기존 AODV, MMBCR 방식 등과 비교했을 때 네트워크 생존 시간이 최대 40% 증대됨을 알 수 있다.

객체지향 지리정보 데이터베이스를 위한 색인기법 (An Indexing Technique for Object-Oriented Geographical Databases)

  • 부기동
    • 한국지역지리학회지
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    • 제3권2호
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    • pp.105-120
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    • 1997
  • 객체지향 지리정보 데이타베이스 시스템의 설계시 중요한 고려 사항은 저장된 데이타에 대한 좋은 접근 전략을 갖도록 하는 것이다. 객체지향 시스템에서는 이러한 목적으로 여러가지 색인 기법이 개발되었으나, 이러한 기법들은 객체지향 데이타 모델의 집단화 계층이나 상속 계층 중 어느 한 가지만을 고려하는 경우가 대부분이었다. 본 연구에서는 포인터 체인 디렉토리를 이용하여 객체지향 지리 데이터베이스의 집단화 및 상속 계층을 접근하는 데 효율적인 색인 기법을 제안하였다. 제안된 기법의 효용성을 기존의 색인 기법들과 다양하게 비교하였으며, 저장비용과 검색비용 측면에서 그 성능을 시뮬레이션한 결과를 제시하였다.

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고로슬래그 미분말의 치환율 증가에 따른 고강도 콘크리트의 공학적 특성 분석 (Engineering Characteristics Analysis of High Strength Concrete Followed in replacement ratio increase in Blast Furnace Slag)

  • 한천구;김성환;손호정
    • 한국건설순환자원학회논문집
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    • 제4권3호
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    • pp.62-68
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    • 2009
  • 본 연구는 BFS치환율 증가에 따른 고강도 콘크리트의 제반 공학적 특성을 검토하였는데, 그 결과를 요약하면 다음과 같다. 굳지않은 콘크리트의 유동성은 BFS 치환율이 증가할수록 증가하는 경향을 나타내었고, 공기량은 다소 감소하는 경향을 나타내었으나 AE제 사용량 증가로 적정량의 공기량 확보는 가능할 것으로 판단된다. 응결시간은 BFS 치환율이 증가할수록 비례적으로 크게 지연되는 것으로 나타났다. 경화 콘크리트의 압축강도는 BFS의 잠재수경성 반응에 기인하여 BFS 치환율이 증가할수록 재령 28일 미만에서는 OPC에 비하여 저하하였으나, 그 이후 재령에서는 동등 이상의 수준을 발휘 하는 것으로 나타나 특히, 고강도 콘크리트의 활용에 탁월한 효과가 있는 것으로 분석되었다. 건조수축길이 변화율은 W/B가 클수록 수화반응시 콘크리트 내부에 존재하는 자유수의 양이 증가함에 기인하여 다소 크게 나타났고, BFS 치환율이 증가할수록 건조수축량은 증가하는 경향이 나타났으나, 모든 배합에서 $-500{\times}10^{-6}$이하로 비교적 양호하였다.

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