• Title/Summary/Keyword: Stability Criteria

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Application of EPS Considering Long-term Durability (장기내구성을 고려한 EPS의 현장 적용성)

  • Chun, Byungsik;Jung, Changhee;Ahn, Jinhyun
    • Journal of the Korean GEO-environmental Society
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    • v.8 no.6
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    • pp.53-60
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    • 2007
  • L/EPS, manufactured in the shape of block and used for civil engineering, is a lightweight material with an excellent resistance to compression, and provides a superb self-sufficient stability. EPS is a suitable material capable of resolving the problem of settlement and lateral flow if it is applied as the soil on soft ground. The Korean Standards (KS) has not yet proposed any testing method for use of EPS as an engineering banking material. Only its testing and quality ordinance as a heat insulation material has been standardized. The design criteria for EPS has been established and applied through the trial construction of KHC (Korea Highway Corporation) and quality test of manufacturer, but most studies on them have been confined to factory products. This study is focused on comparing and analyzing long-term durability by conducting cyclic load test, freezing and thawing test, absorption rate test and others. EPS used in the test was chosen from construction sites and factory products, focusing on the long-term durability of EPS depending on the passage of time. Unconfined compression test results indicated that the strength of collected samples was lower than factory products. While the triaxial compression test results indicated that the shear strength increased in proportion to the increase of confining pressure, and factory products had declining shear strength as the confining pressure rose.

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Measurement of Muscle Strength of Ankle Joint Using Isokinetic Dynamometer in Normal Korean Adults (등속성 운동검사를 이용한 정상 한국인 성인에서의 발목관절 근력 측정)

  • Choi, Seung-Myung;Park, Ji-Kang;Ha, Yoon-Won;Cho, Byung-Ki
    • Journal of Korean Foot and Ankle Society
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    • v.19 no.4
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    • pp.142-150
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    • 2015
  • Purpose: Restoration of ankle stability through the strengthening exercise of peroneus muscles is considered an important factor for achievement of successful outcomes, in the rehabilitation program following ankle ligament injuries. However, there were few definitive data on normal muscle strength, including eversion power by peroneus muscles. This study was conducted to evaluate the muscle strength of ankle joint measured using an isokinetic dynamometer in normal Koreans. Materials and Methods: Sixty adults (120 ankles) were recruited and divided into three groups (20 in their twenties, 20 in thirties, and 20 in forties). Each group consisted of 10 males and 10 females. The selection criteria were no history of ankle injury and no evidence of instability. The peak torque, total work, and deficit ratio were measured using the Biodex$^{TM}$ (Biodex Medical Systems). Differences in muscle strength by age, gender and dominant versus non-dominant side were analyzed. Results: The peak torque of dorsiflexion was average 31.5 Nm at $30^{\circ}/s$ of angular velocity and 18.8 Nm at $90^{\circ}/s$; average 69.3 Nm ($30^{\circ}/s$) and 42.4 Nm ($90^{\circ}/s$) on plantarflexion; average 19.6 Nm ($30^{\circ}/s$) and 10.8 Nm ($90^{\circ}/s$) on inversion; average 12.9 Nm ($30^{\circ}/s$) and 8.0 Nm ($90^{\circ}/s$) on eversion. The deficit ratio of strength in women was average 61.1% of men on dorsiflexion; average 66.2% on plantarflexion; average 48.5% on inversion; average 55.4% on eversion. The deficit ratio in non-dominant foot was average 88.6% of dominant foot on dorsiflexion; average 90.1% on plantarflexion; average 85.1% on inversion; average 85.6% on eversion. Conclusion: The muscle strength of the ankle joint showed a tendency to weaken with age. There were significant differences in muscle strength by gender and dominancy. Further studies for comparison of patients with ankle instability, a comparison between before and after surgery for instability, the correlation between clinical outcomes and the recovery in muscle strength will be needed.

Changes in Spectroscopic Characteristics of Bark and Piggery Manure By-Product Composts During the Composting (수피${\cdot}$돈분 부산물 비료의 부숙단계별 분광학적 특성 변화)

  • Yang, Jae-E;Park, Chang-Jin;Shin, Myung-Kyo;Park, Yong-Ha;Choi, Moon-Heon;Kim, Jeong-Gyu;Kim, Jeong-Je
    • Korean Journal of Environmental Agriculture
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    • v.18 no.4
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    • pp.378-383
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    • 1999
  • Changes of the spectroscopic characteristics of the organic matter fractions and circular filter paper chromatograph were assessed for the bark and piggery manure composts during the composting. as an approach to base the criteria of the compost maturity evaluation. Contents of humic acid-C (HA-C) and fulvic acid-C (FA-C) in both bark and piggery manure composts were decreased as the composting got closer to maturity, but the ratios of HA-C/FA-C were increased. During the composting. ${\Delta}log$ K values were decreased, but RF values were increased. Humic acid of the mature bark compost after 120 days of composting was A-type, as compared to Rp-type for the raw bark and B-type for the immature compost. However. humic acid of the mature piggery manure composts after 40 days of composting was B-type, indicating the humification of the organic matter fractions continued at this stage. Circular filter paper chromatograph of the mature bark compost exhibited the regular sawteeth pattern at the edge, but that of the mature piggery manure showed an irregular sawteeth pattern. Results demonstrated that spectroscopic characteristics and circular filter paper chromatograph of the organic by-product composts might be employed for the compost stability assessment.

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The Limitations of Advance Directive (사전의료지시의 한계)

  • Oh, Se-Hyuk;Jeong, Hwa-Seong
    • The Korean Society of Law and Medicine
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    • v.11 no.2
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    • pp.239-274
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    • 2010
  • Advance directive refers to a description of the treatment method a patient wants to be provided with in case where the person is unconscious or lacks an ability to decision making in a future period or a declaration of intention that delegates and appoints another person who makes a decision regarding a treatment method on behalf of the person. Advance directive is usually a document form, but oral statement is acceptable as well. Advance directive may have a variety of forms though, it basically consists of two basic forms. That is, one is a living will, and the other is a surrogate decision making. Though the importance of advance directive has been emphasized, and the necessity of adopting the system has been strongly argued for so far, the debates on criteria, method, and procedure alike have not yet reached an agreement. It is because even the concept of advance directive is more or less ambiguous, and each specific method has its own theoretical limitations and practical constraints. Thus the inquiries on advance directive raised in the study are summarized as the meaning, practicability, and philosophical foundation of the advance directive. Firstly, the theoretical limitations of Advance directive may be categorized into conceptual and moral limitations. In case of conceptual limitations, authors of advance directives may not be well aware, in advance, of the particular situation in which he or her will experience in the future, and patients may experience the change in his or her values and lack the understanding and information about the future situation due to the changes in treatment methods. In case of moral limitations, a patient has a limited moral autonomy right and self identity that have an impact on his or her preference. Secondly, in case of practical constraints for advance directive, there exist cultural features, low ratio of documentation, as patients themselves admit, and low predictability and stability of patient's own preference regarding life-sustaining care. And the problem of validity and accuracy in proxy's decision making is also raised. Those who administer a living will, especially, may have a difficulty in understanding the directive by a patient, so that the accuracy of execution cannot be secured. In the sense, it is needed to implement a legal device in order to solve such problems. In summary, it is urgently required to understand the limitations and explore desired alternatives to overcome the relevant problems in advance, which must contribute to successfully adopting and effectively operating the advance directive system in Korea.

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Analysis of Buckling Causes and Establishment of Reinforcement Method for Support of Plate Girder Bridge (플레이트 거더교 지점부의 좌굴발생 원인분석 및 보강방안 수립)

  • Ok, Jae-Ho;Yhim, Sung-Soon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.11
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    • pp.520-526
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    • 2019
  • I-type girders are widely applied as very economical sections in plate girder bridges. There has been research on developing composite laminated panels, curved plates reinforced with closed-end ribs, and new forms of ribs and compression flanges for steel box girders. However, there is a limitation in analyzing the exact cause of local buckling caused by an I-type girder's webs. Therefore, an I-type girder's web was modeled using the finite element analysis program LUSAS 17.0 before and after reinforcement. We checked for the minimum thickness criteria presented in the Korea highway bridge design code, and the cause of buckling after performing a linear elastic buckling analysis of dead and live loads was analyzed. Before reinforcement, an eigenvalue (λ1) at the 1st mode was 0.7025, the critical buckling load was smaller than the applied load, and there is a buckling. After reinforcement, when applying vertical and horizontal stiffeners to the web part of the girder at support, a Nodal line was formed, the eigenvalue was 1.5272, and buckling stability was secured. To improve buckling trace of the girder at the support, an additional plate was applied to the web at the support to ensure visual and structural safety, but buckling occurs at center of web. The eigenvalue (λ1) was 3.5299, and this method is efficient for reinforcing the web of the support.

Inspecting Stablity of DSM method with Grouting on Tunnel Face using Chamber Test and Numericlal Analysis (토조실험과 수치해석을 이용한 막장면 그라우팅 DSM공법의 안정성 검토)

  • Kim, Young-Uk;Park, Young-Bok;Kim, Li-Sak;Kim, Nak-Kyeong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.3
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    • pp.677-683
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    • 2016
  • In urban areas, underground tunnel construction sites have spread widely to accommodate rapidly increasing traffic volume along with a high-degree economic growth. Earth tunneling might be adapted frequently for the underground space securing, and various tunneling methods have been developed to stabilize the tunnel face and crown. Among them, the DSM (divided shield method) is gaining popularity for its enhanced stability and construction efficiency. This method has its foundation from the Messer Shield method, which is one of the trenchless special tunneling methods. This study examined the effects of face reinforcement on construction the sequence through a large scale soil chamber test and numerical analyses. The chamber has a size of a 1/2 scale of the real tunnel. Surface settlements were measured according the tunneling process. Commercially available software, MIDAS GTS, was used for numerical analysis and its result was compared with the values obtained from the chamber test. The results of the study show that both settlements of the embanked soils and the stress of the tunnel girder are located within the safe criteria. Overall, this study provides basic data and the potential of using a reinforced tunnel face to enhance DSM applications.

정보통신연구개발사업의 우선순위 설정과 적정자원 배분 - 다기준의사결정(MCDA) 방법의 적용사례 -

  • 황용수;장진규
    • Proceedings of the Korea Technology Innovation Society Conference
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    • 1999.05a
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    • pp.539-563
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    • 1999
  • 이 논문은 정보통신정책 목표와의 연관성 속에서 정보통신연구개발사업의 우선순위를 설정함과 아울러 비용효과성에 바탕을 둔 적정 자원배분 도출하는데 주안점을 두고 있다. 복합적인 목표를 가진 연구개발사업에 대해 사업부문별 그리고 기술분야별로 객관적이면서도 설득력있는 자원배분지침을 마련하기 위하여 본 연구는 다기준의사결정(MCDA: Multi-criteria Decision Analysis) 방법을 채택하고 있다. 이 방법론에서는 사업의 목표와 우선순위 판단기준 및 사업대안이 계층적으로 연계된 분석구조를 설계하여 사업대안의 우선순위를 먼저 설정하고, 여기에 정수계획법(Integer Programming)을 결합하여 사업의 목표와 연계된 비용-편익 관계(Cost-benefit relationship)를 최적화하는 바탕 위에서 사업대안별 자원배분 시나리오를 제시하게 된다. 이러한 절차로 사업부문별 및 기술분야별로 각각 도출된 8개의 자원배분 시나리오는 자원배분 경향치의 안정성(Stability) 분석과 자금지원의 과부족에 대한 현실적 적합성(Relevance) 분석을 거쳐 최종적으로 하나의 적정 자원배분방안으로 수렴되도록 하였다. 우선순위 설정에 기초가 되는 사업대안의 편익에 대한 자료는 전문가의 정성적 판단을 통해 수집되었는데, 이를 위해 정보통신기술 부문에서 활동 중인 중견 이상의 총 58명의 산학연 전문가를 대상으로 한 조사를 실시하였다. 먼저, 기초기반ㆍ전략기술개발사업, 연구ㆍ기술인력양성사업, 산업응용기술개발사업, 기술기반조성사업 등 4대 사업부문에 대해서는 (ⅰ) 정보통신 기술능력의 축적, (ⅱ) 정보통신산업의 경쟁력 강화, (ⅲ) 정보통신기반의 기술고도화, (ⅳ) 정보화를 위한 기술역량의 제고 등 주요 사업의 편익을 나타내는 4개 기준으로 우선 순위를 판단하였고, 정보통신망기술, 전파 및 RF 기술, 정보처리기술, 반도체 소자/설계 기술 등 13개 기술분야에 대해서는 (ⅰ) 공공정책적 임무에 대한 기여, (ⅱ) 기술자립기반의 확충, (ⅲ) 기술발전성과 기술적 파급효과, (ⅳ) 기술적 산물의 시장잠재력 등 기술분야 연구개발을 통한 편익을 나타내는 4개 기준으로 우선순위를 판단하였다. 우선순위는 사업대안에 대한 가중치로 표시되었고, 적정 자원배분방안은 추정된 총예산 규모에 따라 지원수준에 대한 일정한 제약조건 하에서 비용-편익 관계에 따른 자원의 최적 할당량으로 제시되었다. 본 연구는 총예산 규모의 가변성, 사업 및 기술분야 대안의 분류체계에 대한 공감대 부족, 사업목표의 상호연관성과 우선순위 판단기준의 부분적 중첩성 등 여러 제약요인이 있어 도출된 구체적인 수치보다는 방향성에 더 큰 의미를 부여하는 것이 바람직하다. 그러나, 이러한 연구의 한계에도 불구하고 도출된 우선순위와 적정 자원배분방안은 문제해결의 실행타당성을 감안하여 비교적 객관적이고 균형있는 결과로 판단된다.

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A Study on the Improvement of Performance Testing System of Domestic Surveying Equipment (국내 측량장비 성능검사제도 개선방안 연구)

  • MIN, Kwan-Sik
    • Journal of the Korean Association of Geographic Information Studies
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    • v.19 no.1
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    • pp.53-63
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    • 2016
  • In this paper, we proposed the improvements for performance test and surveying equipment regulations, standards, methods and procedures, depending on the need of improving the legal system for surveying equipment in a diverse and sophisticated surveying industry. This research was performed first investigating the existing legal systems(Act on the establishment and management of spatial data, Framework act on national standards, ISO 17123, JIS B 7912) with respect to the surveying equipment performance testing and the research for IOS and KOLAS suggested the improvements on the application for the surveying equipment performance testing standard. More exactly, first, two years were presented for the surveying equipment performance testing cycle considering the precise accuracy of the instrument stability, purpose and frequency of use, etc. Second, the abolition of the measurement distance by grade and the upward or cross-grade adjustment of the single prism standards about the light wave rangefinder and total station were suggested for the improvement on survey equipment performance criteria. Third, since the main function of total station is focused on a three-dimensional coordinate measurement due to the improvement of surveying equipment performance testing, it was proposed to use the precision(repeatability) of the coordinate measuring method as an evaluation method.

Numerical Study on Freezing and Thawing Process in Modular Road System (모듈러 도로시스템의 동결-융해에 대한 수치해석적 연구)

  • Shin, Hosung;Kim, Jinwook;Lee, Jangguen;Kim, Dong-Gyou
    • Journal of the Korean Geotechnical Society
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    • v.33 no.3
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    • pp.49-62
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    • 2017
  • In order to understand response of geo-structures to the freezing-thawing process in the ground, it is necessary to consider phase change of the pore water of the ground and also to understand soil interaction with structures. In this study, numerical analysis was carried out for freezing and thawing effect on the modular road system. Neumann's theoretical equation for freezing-thawing processes in porous media can be used to estimate frozen depth and heaving from basic soil properties and ground and surface temperature, but its application is limited to the case for the sediment with fully saturated condition and zero unfrozen water content. Numerical analysis of the modular road system was performed on various soil types and different ground water table as the varying freezing index. The amount of heaving in the silty soil was much larger than those in granite weathered soil or sandy soil, and lowering groundwater level reduced ground heaving induced by freezing. Numerical analysis for temperature history of the ground surface predicted residual heaving near the surface by the freeze-thaw process in silty soil. It ought to reduce stiffness and bearing capacity of the ground so that it will impair stability and serviceability of new road system. However, the amount of residual heaving was insignificant for the road system installed in weathered soil granite and sandy soil. Since modular road system is a pavement structure mounted on the supporting substructure unlike the prevalent road pavement system, strict criteria should be applied for uniform and differential settlement of the pavement system.

Evaluation Index for U-city Status Diagnostic Assessment System based on Local Governments (지자체 U-City 수준진단체계 평가지표)

  • Lee, Mee Young;Shin, Ju Ho;Lee, Jae Yong
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.15 no.5
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    • pp.20-28
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    • 2016
  • A Ubiquitous City (U-city, Smart City) is one that ties information communications technologies (ICT) into many facets of city construction, thereby implicitly intending to function as a smart city that aims to be efficiently managed as well as provide an enhanced standard of living for its residents. Laws related to the construction of such ubiquitous cities point to integrated city management centers, intelligent facilities, and U-City infrastructure, among others, as central components of U-Cities, but do not provide a standard for these structures. Consequently, building of U-Cities by local governments are based on arbitrary judgments constrained the myriad of practical limitations that they face. Such ambiguity brings to light the need to find ways to improve the quality of these efforts. The first and second stages of this research examine the status of the components of a U-City -ubiquitous planning, technology, infrastructure, and services - and undertakes a comprehensive review thereof, with evaluation criteria formulated on the characteristics of stability, connectivity, goal-orientation, and development potential. In the research's third stage, a realistic and detailed evaluation index by which U-Cities can be renewed, demonstrated, and applied (???) is introduced in a step-by-step fashion, which will allow for local governments to properly assess the standard of their U-City in relation to the realities of the locality. Through the research result, it is expected that the index will become a part of the continued development and advancement of the "smart" character of an autonomous U-City at the local scale, and contribute to the overall revitalization of the U-City.