• 한국터널지하공간학회 논문집
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• 제16권5호
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• pp.497-506
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• 2014

본 연구에서는 동반논문에서 수행한 해석 결과를 이용하여 주방식 지하구조물의 안정성, 공간 활용성, 시공장비 적용성을 검토하였다. 지하구조물 안정성은 강도응력비와 한계변형률 개념을 도입하여 적용하였으며 공간 활용성은 주어진 단면에 대한 공간의 비율로 활용률을 판단하였고 시공장비 적용성은 굴착공사에서 사용되는 대표 장비를 선정하고 장비의 회전반경을 고려하였다. 제안된 일련의 과정을 통해 모두 조건을 만족하는 지하구조물 형상을 선정할 수 있었으며 선정된 단면에 대한 지보재 설계가 가능할 것으로 나타났다.

• 한국전자거래학회지
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• 제16권2호
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• pp.19-37
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• 2011

인터넷의 발달과 함께 온라인을 통한 상거래 활동은 급증해 왔다. 전자상거래 초기에 기존의 오프라인 업체들과 온라인 업체들 간의 가격수준 및 편차에 대한 연구들이 많이 이루어졌으나, 전자상거래가 활성화되고 성숙된 지금은 이러한 채널 유형별 비교보다는 전자상거래 업체들의 가격변화 행태에 대한 연구가 필요하다. 이에 따라 본 연구에서는 전자상거래 상에서 제품이 판매되기 시작한 시점부터 시간이 흐름에 따라 가격이 어떻게 변화하는지를 분석하였다. 가격비교 사이트로부터 가격자료를 수집하여 분석에 활용하였다. 이를 통해 시간이 흐를수록 최저가와 평균가격이 하락하는 것을 보였으며, 최고가는 시간이 흐를수록 오히려 상승하는 패턴을 보였다. 최고가의 상승에는 판매업체 수 증가가 양의 영향을, 출시 이후 기간이 음의 영향을 미치는 것을 보였으며 이 두 가지의 영향력에 따라 제품군별로 상이한 상승 패턴을 보였다. 또한, 제품군의 유형별로도 판매업체 수에 따라 상이한 가격변화 패턴을 보였다.

• 한국한의학연구원논문집
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• 제13권3호
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• pp.165-178
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• 2007

This article explores how non-dominant medical practitioners shape their own self-images and the identity of relevant medicine and in what ways fashioning of self-images and accompanying modalities of medical practice informs the social evolution of the medicines at specific times and over specific places, by means of the historical configuration of osteopathy and chiropractic in the UK and the US. Attention is directed onto motivations and pursuits for professional recognition and actual strategies and activities of non-dominant medicines and its practitioners by turning to historical instances such as osteopathy and chiropractic in the UK and the US, not least drawing focus on professional desires with regard to circumstances it faces within and without. Some non-dominant medicines as a way with which to acquire and protect the exclusive monopoly of its knowledge and practical skills, adopted various forms of professionalism project, as dominant biomedical groups pressed up non-dominant medicines by virtue of marginalizing tactics. Meanwhile, non-dominant medicines took somewhat distinctive professionalisation strategies from each other. Strategies they took were diversified depending on medical philosophy, healing modality, the degree of occupational solidarity embodied as forms of medical organisation, and especially vocational aspiration and prospect. Change of socio-medical culture and the state's policy seems to have wielded critical influenceon the determination of the ups and downs of non-dominant medicines. From the perspective of long-term time span, dominant biomedicine eventually did not have much influence on the ups and downs of marginalized medicines in so far as in the case of osteopathy and chiropractic in Englandand the U. S.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.941-945
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• 2006

In the development of electricity generating wind turbines for wind farm application, only two types have survived as the methods of power regulation; stall regulation and fun span pitch control. The sound measurement procedures of IEC 61400-11 are applied to field test and evaluation of noise emission from each of 1.5 MW and 660 kW wind turbine generators (WTG) utilizing the stall regulation and the pitch control for the power regulation, respectively. Apparent sound power level, wind speed dependence and third-octave band levels are evaluated for both of WTGs. It is found that while 1.5 MW WTG using the stall control is found to emit lower sound power than 660 kW one using the pitch control at low wind speed (below 8 m/s), sound power from the former becomes greater than that of the latter in the higher wind speed. Equivalent continuous sound pressure levels (ECSPL) of the stall control type of WTG vary more widely with wind speed than those of the pitch control type of WTG These characteristics are believed to be strongly dependent on the basic difference of the airflow around the blade between the stall regulation and the pitch control types of WTG. These characteristics according to the methods of power regulation lead to the very different noise emission characteristics of WTG depending on the seasons because the average wind speed in summer is lower than the critical velocity over which the airflow on the suction side of blade in the stall types of WT are separated. These results propose that, in view of environmental noise regulation, the developer of wind farm should give enough considerations to the choice of power regulation of their WTG based on the weather conditions of potential wind farm locations.

• 한국응용곤충학회지
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• 제31권4호
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• pp.371-378
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• 1992

검정금파리의 변태에 따른 엑디스테로이드를 Radioimmunoassay법으로 측정하고, 난세포성숙에 미치는 엑디스테로이드의 효과를 조사하여 얻을 결과는 다음과 같다. 산락직후 존재하였던 난내 엑디스테로이드는 발생과정 중 감소하다가 부화 직전 다시 증가하였으며, 유충기와 용기의 성장 변태시 엑디스테로이드함량의 변화를 보면 유충-유충과 유충-용으로의 탈피시에 일시적인 증가현상을 나타냈다. 특히 용화 후 48시간에 높은 엑디스테로이드의 농도를 보였는데 이는 큐티클분비와 경화작용과 밀접한 관계가 있는 것으로 생각된다. 성충기에서는 수컷의 경우 엑디스테로이드가 거의 검출 되지 않은 반면, 암컷에서는 단백질원 섭식 후 96시간에 최고의 함량을 나타내어 난성숙도와 일치하는 변화를 보였다. 엑디스테로이드 처리와 난성숙도와의 관계를 보면, 1$\mu$g 처리군은 대조군에서와 같은 성숙도를 나타내 차이를 보이지 않았으나, 5$\mu$g처리군에서는 대조군에서 보다 12시간 빠르게 난세포성숙이 완료되어, 엑디스테로이드 처리시 임계농도 이상에서는 난세포조기성숙에 직접적인 영향을 미치는 것으로 나타났다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.213-216
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• 2008

슬래브에 폴리스티렌을 이용한 경량폼을 적용할 경우, 슬래브 중량이 감소함에 따라 보다 경간이 증가하거나 슬래브 지지 부재 크기가 감소될 수 있다. 하지만 플랫플레이트 구조에서 경량폼을 사용한 슬래브는 기둥주위 위험단면에서의 뚫림전단성능이 저하될 수 있다. 그러나 이에 관한 내력산정을 위한 기준이 없으며, 기존 연구 또한 부족한 실정이다. 본 논문은 폴리스티렌 경량폼을 사용한 슬래브-기둥 접합부의 뚫림전단내력을 파악하기 위하여 실시한 뚫림전단 실험에 관한 것이다. 주요 변수는 기둥의 크기, 폴리스틸렌 폼의 배치형태, 전단보강 유무 등으로 총 4개 실험체를 계획하였다. 실험을 통하여 균열 및 파괴모드, 하중-변위곡선, 뚫림전단강도 등을 분석함으로써 경량폼을 사용한 슬래브의 뚫림전단 성능을 파악하였다.

• 한국건설관리학회논문집
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• 제19권1호
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• pp.32-42
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• 2018

시설 관리는 시설의 자산적 가치뿐만 아니라 시설 환경 및 사용자 성능까지도 시설 관리 수준에 의해 결정된다는 점에서 매우 중요하다. 시설 전체 생애 비용 중 운영 및 관리 비용은 시설의 용도와 사용 정도에 따라서 초기 건설비용의 3배에서 10배에 달한다. 효율적인 시설 관리는 다양한 용도로 건설된 다수의 시설을 관리하는 공공 시설관리 기관의 경우 더욱 중요하며, 특히 제한된 자원(인력/장비 등)과 제한된 예산으로 다양한 사용자를 위한 다양한 시설을 관리할 때 이 중요성은 증폭된다. 본 연구는 전국에 있는 16개의 공공 시설관리기관의 시설관리 현황을 조사 분석하였다. 주요 조사 항목은 1) 시설 관리 시스템 구성 및 활용현황, 2) 중장기 수선 계획 수립 및 활용현황, 3) 수선대안 선정 시스템 수립 및 활용현황 등이다. 본 연구는 분석 자료를 기반으로 지방 공공 시설관리 기관에서 사용하고 있는 시설관리 시스템의 개선 사항을 도출하고 추후 연구 방향을 제시한다.

• Structural Engineering and Mechanics
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• 제39권2호
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• pp.241-266
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• 2011

The Self Compacting Concrete, SCC is the new generation type of concrete which is not needed to be compacted by vibrator and it will be compacted by its own weight. Since SCC is a new innovation and also the high strength self compacting concrete, HSSCC behavior is like a brittle material, therefore, understanding the strength effect on the serviceability performance of reinforced self compacting concretes is critical. For this aim, first the normal and high strength self compacting concrete, NSSCC and HSSCC was designed. Then, the serviceability performance of reinforced connections consisting of NSSCC and HSSCC were investigated. Twelve reinforced concrete connections (L = 3 m, b = 0.15 m, h = 0.3 m) were simulated, by this concretes, the maximum and minimum reinforcement ratios ${\rho}$ and ${\rho}^{\prime}$ (percentage of tensile and compressive steel reinforcement) are in accordance with the provision of the ACI-05 for conventional RC structures. This study was limited to the case of bending without axial load, utilizing simple connections loaded at mid span through a stub (b = 0.15 m, h = 0.3 m, L = 0.3 m) to simulate a beam-column connection. During the test, concrete and steel strains, deflections and crack widths were measured at different locations along each member. Based on the experimental readings and observations, the cracked moment of inertia ($I_{cr}$) of members was determined and the results were compared with some selective theoretical methods. Also, the flexural crack widths of the members were measured and the applicability for conventional vibrated concrete, as for ACI, BS and CSA code, was verified for SCCs members tested. A comparison between two Codes (ACI and CSA) for the theoretical values cracking moment is indicate that, irrespective of the concrete strength, for the specimens reported, the prediction values of two codes are almost equale. The experimental cracked moment of inertia $(I_{cr})_{\exp}$ is lower than its theoretical $(I_{cr})_{th}$ values, and therefore theoretically it is overestimated. Also, a general conclusion is that, by increasing the percentage of ${\rho}$, the value of $I_{cr}$ is increased.

• Computers and Concrete
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• 제7권3호
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• pp.203-220
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• 2010

In the present study, exterior beam-column sub-assemblage from a regular reinforced concrete (RC) building has been considered. Two different types of beam-column sub-assemblages from existing RC building have been considered, i.e., gravity load designed ('GLD'), and seismically designed but without any ductile detailing ('NonDuctile'). Hence, both the cases represent the under-designed structure at different time frame span before the introduction of ductile detailing. For designing 'NonDuctile' structure, Eurocode and Indian Standard were considered. Non-linear finite element (FE) program has been employed for analysing the sub-assemblages under cyclic loading. FE models were developed using quadratic concrete brick elements with embedded truss elements to represent reinforcements. It has been found that the results obtained from the numerical analysis are well corroborated with that of experimental results. Using the validated numerical models, it was proposed to correlate the energy dissipation from numerical analysis to that from experimental analysis. Numerical models would be helpful in practice to evaluate the seismic performance of the critical sub-assemblages prior to design decisions. Further, using the numerical studies, performance of the sub-assemblages with variation of axial load ratios (ratio is defined by applied axial load divided by axial strength) has been studied since many researchers have brought out inconsistent observations on role of axial load in changing strength and energy dissipation under cyclic load.

• Steel and Composite Structures
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• 제34권1호
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• pp.123-139
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• 2020

The tube outward local buckling of Concrete-Filled Steel Tube (CFST) beam under high compression stress is still considered a critical problem, especially for steel tubes with a slender section compared to semi-compact and compact sections. In this study, the flexural performance of stiffened slender cold-formed square tube beams filled with normal concrete was investigated. Fourteen (14) simply supported CFST specimens were tested under static bending loads, stiffened with different shapes and numbers of steel stiffeners that were provided at the inner sides of the tubes. Additional finite element (FE) CFST models were developed to further investigate the influence of using internal stiffeners with varied thickness. The results of tests and FE analyses indicated that the onset of local buckling, that occurs at the top half of the stiffened CFST beam's cross-section at mid-span was substantially restricted to a smaller region. Generally, it was also observed that, due to increased steel area provided by the stiffeners, the bending capacity, flexural stiffness and energy absorption index of the stiffened beams were significantly improved. The average bending capacity and the initial flexural stiffness of the stiffened specimens for the various shapes, single stiffener situations have increased of about 25% and 39%, respectively. These improvements went up to 45% and 60%, for the double stiffeners situations. Moreover, the bending capacity and the flexural stiffness values obtained from the experimental tests and FE analyses validated well with the values computed from equations of the existing standards.