• 제목/요약/키워드: Joint international standard

검색결과 65건 처리시간 0.024초

절대절점좌표를 이용한 고속철도 집전성능 동역학 해석 모델 개발 및 검증 (Development and Verification of a Dynamic Analysis Model for the Current-Collection Performance of High-Speed Trains Using the Absolute Nodal Coordinate Formulation)

  • 이진희;박태원
    • 대한기계학회논문집A
    • /
    • 제36권3호
    • /
    • pp.339-346
    • /
    • 2012
  • 철도차량의 집전성능 및 이선율에 대한 사전 평가는 철도차량의 고속화와 더불어 중요시되는 문제이다. 본 논문에서는 유연체 다물체 동역학 해석 기법을 이용하여 가선과 판토그래프 사이의 동적상호작용에 대한 시뮬레이션 모델을 개발하였다. 해석 모델에서 판토그래프는 강체로 모델링 하였으며, 가선계는 탄성 대변형체의 거동을 효과적으로 표현할 수 있는 절대절점좌표를 이용하여 구현하였다. 또한, 가선계와 판토그래프 간의 동적 상호작용의 표현을 위하여 서로간의 상대운동은 슬라이딩 조인트를 이용하여 구속하였다. 개발된 해석 프로그램을 이용하여 철도차량의 주행 속도에 따라 발생하는 접촉력 및 이선율을 평가하였다. 개발 프로그램의 해석 모델 및 시뮬레이션에 대한 신뢰성은 가선계와 판토그래프의 동적 상호작용 시뮬레이션 방법에 대한 국제 규정인 EN 50318에 의하여 검증하였다. 해석 모델의 개발을 통하여 개발 중인 고속철도의 집전성능을 평가할 수 있는 기반을 마련하였다.

기능적전기자극을 이용한 보행훈련이 편마비 환자의 하퇴근육의 근전위활동에 미치는 영향 (Influence of Functional Electrical Stimulation during Gait Training on Motor Unit Action Potential)

  • 강양훈;서삼기;이정우;윤세원;김용억;김태열
    • 대한임상전기생리학회지
    • /
    • 제5권1호
    • /
    • pp.33-43
    • /
    • 2007
  • This study divided 35 hemiplegia patients into control group having standard physical therapy and gait training and functional electrical stimulation(FES) group using FES during gait training in order to examine the effects of applying FES to ankle joint dorsiflexor on motor unit action potential. Stimulation conditions of FES were pulse rate 35 pps, pulse width $250{\mu}s$, and on-time 0.3 second, treatment hour was 30 min. and treatment period was once a day for five days a week through six weeks. For functional evaluations before and after treatment, root mean square(RMS) were measured and the following conclusions were obtained. : In RMS analysis of motor unit action potential, gastrocnemius was significantly reduced in both weight bearing(p<.001) and bearing condition (p<.05). In conclusion, application of FES to hemiplegia patients in recovery stage during gait training decreased RMS and it was interpreted that it was caused by mitigation of muscular spasticity by reduction of motor unit.

  • PDF

Robust Pelvic Coordinate System Determination for Pose Changes in Multidetector-row Computed Tomography Images

  • Kobashi, Syoji;Fujimoto, Satoshi;Nishiyama, Takayuki;Kanzaki, Noriyuki;Fujishiro, Takaaki;Shibanuma, Nao;Kuramoto, Kei;Kurosaka, Masahiro;Hata, Yutaka
    • International Journal of Fuzzy Logic and Intelligent Systems
    • /
    • 제10권1호
    • /
    • pp.65-72
    • /
    • 2010
  • For developing navigation system of total hip arthroplasty (THA) and evaluating hip joint kinematics, 3-D pose position of the femur and acetabulum in the pelvic coordinate system has been quantified. The pelvic coordinate system is determined by manually indicating pelvic landmarks in multidetector-row computed tomography (MDCT) images. It includes intra- and inter-observer variability, and may result in a variability of THA operation or diagnosis. To reduce the variability of pelvic coordinate system determination, this paper proposes an automated method in MDCT images. The proposed method determines pelvic coordinate system automatically by detecting pelvic landmarks on anterior pelvic plane (APP) from MDCT images. The method calibrates pelvic pose by using silhouette images to suppress the affect of pelvic pose change. As a result of comparing with manual determination, the proposed method determined the coordinate system with a mean displacement of $2.6\;{\pm}\;1.6$ mm and a mean angle error of $0.78\;{\pm}\;0.34$ deg on 5 THA subjects. For changes of pelvic pose position within 10 deg, standard deviation of displacement was 3.7 mm, and of pose was 1.28 deg. We confirmed the proposed method was robust for pelvic pose changes.

Prospects for e-Science In Korea : The role and impacts ol Korea-UK collaboration

  • Kim, Cha-Young;Suh, Jee-Hyun;Tomlinson, Mark
    • 정보처리학회지
    • /
    • 제15권2호
    • /
    • pp.15-28
    • /
    • 2008
  • The Korea UK e-Science Collaboration project has been aimed at supporting research and collaboration between Korean and UK researchers. Its goal is to benefit the nation by reducing cost and time in constructing the National e-Science Research Environment' by studying and benchmarking the cases in countries that have already procured advanced technologies in the area. Two joint workshops were held in a year where researchers from the two countries had the opportunities to share their research results with each other. Also, the project has supported exchanges of researchers fostering expertise in the field. In the course of the project, the e-Science Centre in the UK and KISTI have signed MoU(Memorandum of Understanding) in 2006. Moreover, there have been active research collaboration between Korea and the UK. The University of Southampton will share the BioSimGrid data with the Korean counterpart, and the University of York has provided the AURA software. In the future, KISTI and the UK NGS(National Grid Service) will organize a working group at OGF that will work mainly on the standardization of Parameter Sweep and bring it to lead the global standard. KISTI will include its own AURORA system into OMI-UK software stack, which will enable access to NGS resources through AURORA user application. The collaboration with the UK has opened up more opportunities for collaboration with other countries as well. KISTI and HLRS in Germany have agreed to share the COVISE and will have research exchanges. As such, it is expected that Korea will play a major role in e-Science research by building strategic and systematic collaborative relations with its International partners.

  • PDF

일반철근(SD400) 용접 겹침이음 인장실험 (Tensile Test for Lap Welded Joints of Rebars(SD400))

  • 박원태;천경식
    • 한국산학기술학회논문지
    • /
    • 제19권5호
    • /
    • pp.570-576
    • /
    • 2018
  • 철근콘크리트 구조물에서 철근의 이음은 철근을 겹쳐서 결속선으로 결속한 겹침이음과 커플러에 의한 기계적 이음이 일반적이다. 국내 설계기준(콘크리트구조기준)에서는 일반철근(비용접 철근)에 대해 용접 겹침이음을 제한하고 있으나, 해외기준(AWS D1.4)에서는 예열을 통한 일반철근의 용접 겹침이음을 허용하고 있다. 본 연구에서는 국내외 규격 및 설계기준을 조사하고, 건설현장에서 가장 많이 사용되는 SD400 강종의 일반철근을 대상으로 용접 겹침이음 인장실험을 수행하여 인장강도를 평가하였다. 용접 겹침이음 시험체의 용접길이는 KS규격(KS B ISO 17660-1)에 제시된 최소용접길이인 8d를 적용하고, 예열온도는 AWS D1.4에 따라 D19이하는 $150^{\circ}C$, D22이상은 $260^{\circ}C$로 설정하였다. 인장실험 결과, 용접 겹침이음된 일반철근은 콘크리트구조기준에서 요구하는 인장강도(항복강도의 125%)를 발현하였으며, 모두 철근 모재에서 파단이 발생되었다. 예열 유무에 따른 영향을 검토하기 위해, 일반철근을 예열한 후 용접한 것과 예열 등의 열처리하지 않은 것을 비교한 결과, 인장강도는 큰 차이를 보이지 않았다. 실험시 사용한 일반철근을 대상으로 화학성분을 분석하여 탄소당량(Ceq)을 확인한 결과, 0.45% 이하로 낮았다. AWS D1.4에 따르면, 탄소당량이 0.45% 이하면 예열이 필요하지 않은 조건이다. 결과적으로 예열의 영향이 미비한 것은 일반철근의 탄소당량이 낮았기 때문인 것으로 확인되었다.

외측상과염의 도침 치료에 대한 체계적 문헌고찰 및 메타분석 (Effect of Acupotomy Treatment for Lateral Epicondylitis: A Systematic Review and Meta-Analysis)

  • 최종찬;지민준;서경준;권도영;양재은;구지향;이은정;오민석
    • 한방재활의학과학회지
    • /
    • 제34권2호
    • /
    • pp.101-134
    • /
    • 2024
  • Objectives The purpose of this study is to observe the effectiveness of acupotomy treatment for lateral epicondylitis by comparing it with various control groups. Methods We searched 11 domestic and international databases for systematic reviews and meta-analysis. The subjects were studies published from January 1, 2017 to September 1, 2023, and only randomised controlled trials were included. Results 208 studies were searched, of which 21 studies were finally selected. Among the studies published after 2017, the largest number of studies was published in 2019. The average number of participants per study was 72.28±20.26 and the average age was in the 40s. The most frequent intervention in the study was acupotomy alone, and the treatment most often mentioned as a control group was local nerve block. The most used evaluation tool is efficiency. Acupotomy+manipulation had statistically better effect than that of local nerve block in terms of pain (standard mean difference -1.87, 95% confidence interval, -2.18 to -1.57, p<0.00001) and elbow joint function (standard mean difference 2.25, 95% confidence interval, 1.65 to 2.86, p<0.00001). Conclusions As a result of the meta-analysis, the effect of acupotomy added manual therapy treatment was statistically significant compared to the local nerve block frequently used for lateral epicondylitis. Based on these results, it appears that more research on combination treatments other than acupotomy treatment will be needed. Also, it appears that more large-scale randomized controlled studies that strictly adhere to the standards for reporting interventions in controlled trials of acupuncture, risk of bias 2 criteria will be needed.

변화가 변화를 일으키지 못할 때: 한국과 미국 초등수학 수업 관찰로부터의 소고 (When Changes Don\`t Make Changes: Insights from Korean and the U.S Elementary Mathematics Classrooms)

  • 방정숙
    • 한국수학교육학회지시리즈C:초등수학교육
    • /
    • 제4권2호
    • /
    • pp.111-125
    • /
    • 2000
  • This paper presents cross-national perspectives on challenges in implementing current mathematics education reform ideals. This paper includes detailed qualitative descriptions of mathematics instruction from unevenly successful second-grade classrooms both in Koran and in the U. S with regared to reform recommendations. Despits dramatic differences in mathematics achivement between Korean and the U.S student. problems in both countries with regard to mathematics education are perceived to be very similar. The shared problems have a common origin in teacher-centered instruction. Educational leaders in both countries have persistently attempted to change the teacher-centered pedagogy to a student-centered approach. Many teachers report familiarity with and adherence to reform ideas, but their actual classroom teaching practices do not reflect the full implications of the reform ideals. Given the challenges in implementing reform, this study explored the breakdown that may occur between teachers adoption of reform objectives and their successful incorporation of reform ideals by comparing and contrasting two reform-oriented classrooms in both countries. This comparison and contrast provided a unique opportunity to reflect on possible subtle but crucial issues with regard to reform implementation. Thus, this study departed from past international comparisons in which the common objective has been to compare general social norma of typical mathematics classes across countries. This study was and exploratory, qualitative, comparative case study using grounded theory methodology based on constant comparative analysis for which the primary data sources were classroom video recordings and transcripts. The Korean portion of this study was conducted by the team of four researchers, including the author. The U.S portion of this study and a brief joint analysis were conducted by the author. This study compared and contrasted the classroom general social norms and sociomathematical norms of two Korean and two U.S second-grade teachers who aspired to implement reform. The two classrooms in each country were chosen because of their unequal success in activating the reform recommendation. Four mathematics lessons were videotaped from Korean classes, whereas fourteen lessons were videotaped from the U.S. classes. Intensive interviews were conducted with each teacher. The two classes within each country established similar participation patterns but very different sociomathematical norms. In both classes open-ended questioning, collaborative group work, and students own problem solving constituted the primary modes of classroom participation. However in one class mathematical significance was constituted as using standard algorithm with accuracy, whereas the other established a focus on providing reasonable and convincing arguments. Given these different mathematical foci, the students in the latter class had more opportunities to develop conceptual understanding than their counterparts. The similarities and differences to between the two teaching practices within each country clearly show that students learning opportunities do not arise social norms of a classroom community. Instead, they are closely related to its sociomathematical norms. Thus this study suggests that reform efforts highlight the importance of sociomathematical norms that established in the classroom microculture. This study also provides a more caution for the Korean reform movement than for its U.S. counterpart.

  • PDF

덧씌우기 응력흡수층에 대한 전단, 부착강도 평가 및 파괴에너지 예측모델 개발 (Evaluation of Interlayer Shear Properties and Bonding Strengths of a Stress-Absorbing Membrane Interlayer and Development of a Predictive Model for Fracture Energy)

  • 김도완;문성호;권오선;문기훈
    • 한국도로학회논문집
    • /
    • 제20권1호
    • /
    • pp.87-95
    • /
    • 2018
  • PURPOSES : A geo-grid pavement, e.g., a stress-absorbing membrane interlayer (SAMI), can be applied to an asphalt-overlay method on the existing surface-pavement layer for pavement maintenance related to reflection cracking. Reflection cracking can occur when a crack in the existing surface layer influences the overlay pavement. It can reduce the pavement life cycle and adversely affect traffic safety. Moreover, a failed overlay can reduce the economic value. In this regard, the objective of this study is to evaluate the bonding properties between the rigid pavement and a SAMI by using the direct shear test and the pull-off test. The predicted fractural energy functions with the shear stress were determined from a numerical analysis of the moving average method and the polynomial regression method. METHODS : In this research, the shear and pull-off tests were performed to evaluate the properties of mixtures constructed using no interlayer, a tack-coat, and SAMI with fabric and without fabric. The lower mixture parts (describing the existing pavement) were mixed using the 25-40-8 joint cement-concrete standard. The overlay layer was constructed especially using polymer-modified stone mastic asphalt (SMA) pavement. It was composed of an SMA aggregate gradation and applied as the modified agent. The sixth polynomial regression equation and the general moving average method were utilized to estimate the interlayer shear strength. These numerical analysis methods were also used to determine the predictive models for estimating the fracture energy. RESULTS : From the direct shear test and the pull-off test results, the mixture bonded using the tack-coat (applied as the interlayer between the overlay layer and the jointed cement concrete) had the strongest shear resistance and bonding strength. In contrast, the SAMI pavement without fiber has a strong need for fractural energy at failure. CONCLUSIONS : The effects of site-reflection cracking can be determined using the same tests on cored specimens. Further, an empirical-mechanical finite-element method (FEM) must be done to understand the appropriate SAMI application. In this regard, the FEM application analy pavement-design analysis using thesis and bonding property tests using cored specimens from public roads will be conducted in further research.

두꺼운 콘크리트포장의 원위치파쇄 기층화공법 (Rubblization of Thick Concrete Pavement)

  • 이승우;한승환;고석범;김지원
    • 한국도로학회논문집
    • /
    • 제8권3호
    • /
    • pp.105-114
    • /
    • 2006
  • 노후 콘크리트포장 수명을 연장하기 위한 방안으로 아스팔트 덧씌우기가 일반적이나 반사균열을 억제하기 어렵다는 단점이 있다. 이러한 반사균열을 억제하기 위하여 줄눈부 보수, 응력완화층 설치가 적용되기는 하지만 반사균열의 진전 속도를 늦추는 제한적인 성공을 보여 왔다. 콘크리트포장 슬래브를 원위치에서 파쇄하여 기층재료로 활용하고 그 위에 덧씌우기 포장을 건설하는 원위치파쇄기층화 공법은 기존 덧씌우기 보강공법이 갖고 있는 반사균열 문제를 완벽하게 해결할 수 있는 장점을 가지고 있다. 본 공법을 적용할 경우 파쇄된 노후 콘크리트 포장의 상부층은 40mm-70mm로 파쇄되나 하부층은 100mm 이상 되는 경우가 일반적이다. 그러나 콘크리트 두께가 30cm 이상 되는 경우에는 전체두께를 적정 Size로 파쇄골재화하는 것이 어렵다. 따라서 파쇄된 노후 콘크리트 포장층이 반사균열을 유발시키지 않고 도로기층으로서의 역할을 확보할 수 있는 적정 파쇄 깊이를 파악하기 위하여 파쇄골재깊이를 0cm, 10cm, 20cm로 변화시켜가며 simulation test를 수행한 결과, 적정 파쇄 깊이 10cm를 도출하였다(Lee, 2006). 또한 소형파쇄장비를 제작하여 실제 도로와 동일한 기준으로 시험 포장을 건설하여 파쇄헤드 형상, 파쇄에너지, 유효파쇄 면적 등을 달리하여 두꺼운 콘크리트포장형식에 적합한 파쇄방법을 개발하였으며 Prototype의 파쇄장비를 개발하여 실제 공용중인 고속도로에서 시험시공 및 모니터링을 실시하여 제안된 파쇄방법의 적정성을 검토하였다.

  • PDF

Railway Governance and Power Structure in China

  • Lee, Jinjing
    • International Journal of Railway
    • /
    • 제1권4호
    • /
    • pp.129-133
    • /
    • 2008
  • Over the last $15{\sim}20$years, many countries have adopted policies of railway privatization to keep up with increasing competition from road and air transport. Although each country and case has its own history, market characteristics, political context as well as administrative process, railway privatizations (including railway restructure, concession etc.) in the west usually are accompanied with the establishment of new regulatory regimes. Therefore, railway governance has been innovating towards an interaction of government, regulator, industry bodies, user groups, trade unions and other interested groups within the regulatory framework. However, it is not the case in China. Although China had seen a partial privatization in some branch lines and is experiencing a much larger-scale privatization by establishing joint-ventures to build and operate high-speed passenger lines and implementing an asset-based securitization program, administrative control still occupies absolutely dominant position in the railway governance in China. Ministry of Railway (MOR) acts as the administrator, operator as well as regulator. There is no national policy that clearly positions railway in the transportation network and clarifies the role of government in railway development. There is also little participation from interested groups in the railway policy making, pricing, service standard or safety matter. Railway in China is solely governed by the mere executive agency. Efficiency-focused economic perspective explanation is far from satisfaction. A wider research perspective from political and social regime is of great potential to better explain and solve the problem. In the west, separation and constrains of power had long been established as a fundamental rule. In addition to internal separation of political power(legislation, execution and jurisdiction), rise of corporation in the 19th century and association revolution in the 20th century greatly fostered the growth of economic and social power. Therefore, political, social and economic organizations cooperate and compete with each other, which leads to a balanced and resonable power structure. While in China, political power, mainly party-controlled administrative power has been keeping a dominated position since the time of plan economy. Although the economic reform promoted the growth of economic power of enterprises, it is still not strong enough to compete with political power. Furthermore, under rigid political control, social organizations usually are affiliated to government, independent social power is still too weak to function. So, duo to the limited and slow reform in political and social regime in China, there is an unbalanced power structure within which political power is dominant, economic power expanding while social power still absent. Totally different power structure in China determines the fundamental institutional environment of her railway privatization and governance. It is expected that the exploration of who act behind railway governance and their acting strength (a power theory) will present us a better picture of railway governance as a relevant transportation mode. The paper first examines the railway governance in China and preliminarily establishes a linkage between railway governance and its fundamental institutional environment, i.e. power structure in a specific country. Secondly, the reason why there is no national policy in China is explored in the view of political power. In China, legislative power is more symbolic while party-controlled administrative power dominates political process and plays a fundamental role in Chinese railway governance. And then, in the part three railway finance reform is analyzed in the view of economic power, esp. the relationship of political power and economic power.

  • PDF