• Title/Summary/Keyword: Flow defect

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A Study of Protocol comparison Analysis for MPLS Traffic Engineering (MPLS 트래픽 엔지니어링을 위한 프로토콜 비교 분석에 관한 연구)

  • Ha Yun-sik;Kim Dong-il;Choi Sam-gil
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.9 no.4
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    • pp.772-776
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    • 2005
  • To support abruptly increasing data traffic in these days, network management is needed. And also to maintain the steady infra, there is MPLS need which can support traffic engineering. It's necessary that MPLS doesn't only manage network to support recently booming data traffic, but has capacity to support traffic engineering to keep static infrastructure. Traffic engineering, method that a large-scale user shifts traffic to the beforehand designated routes that pass through specific nodes on network, is operation that is mapping traffic flow to the physical network topology. In this paper, we supplement the defect of the traditional RSVP traffic engineering and to construct far more steady infra, we suggest the way of its development of ERSVP signaling protocol.

A Study on CO2 Emission Factor for Earth-Work Equipment Using C-FVM (C-FVM을 이용한 토공장비의 CO2 배출계수에 관한 연구)

  • Kim, Byung-Soo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.34 no.3
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    • pp.999-1006
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    • 2014
  • $CO_2$ emission factor for earthwork equipment was made based on fuel consumption quantity using IPCC carbon emission factor. This is presented through the carbon emission estimating guideline each facilities by the Ministry of Land, Infrastructure and Transportation in 2011. However, this method has the defect which don't apply the various condition of site. Therefor it needs the new emission factor supplemented these defects. This study will tries to estimate $CO_2$ emission with the direct measurement method using concentration flow velocity measurement (C-FVM) for earth work equipment and present the new $CO_2$ emission factor for earth work equipment after compare with emission factor of the Ministry of Land, Infrastructure and Transportation.

Finite Element Analysis of Multi-Stage Deep Drawing Process for High Precision Rectangular Case with Extreme Aspect Ratio (세장비가 큰 사각컵 디프 드로잉의 유한요소 해석)

  • Ku T.W.;Ha B.K.;Song W.J.;Kang B.S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2002.02a
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    • pp.274-284
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    • 2002
  • Deep drawing process for rectangular drawn section is different with that for axisymmetric circular one. Therefore deep drawing process for rectangular drawn section requires several intermediate steps to generate the final configuration without any significant defect. In this study, finite element analysis for multi-stage deep drawing process for high precision rectangular cases is carried out especially for an extreme aspect ratio. The analysis is performed using rigid-plastic finite element method with an explicit time integration scheme of the commercial program, LS-DYNA3D. The sheet blank is modeled using eight-node continuum brick elements. The results of analysis show that the irregular contact condition between blank and die affects the occurrence of failure, and the difference of aspect ratio in the drawn section leads to non-uniform metal flow, which may cause failure. A series of experiments for multi-stage deep drawing process for the rectangular cases are conducted, and the deformation configuration and the thickness distribution of the drawn rectangular cases are investigated by comparing with the results of the numerical analysis. The numerical analysis with an explicit time integration scheme shows good agreement with the experimental observation.

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Surgical treatment of pulmonary atresia -2 cases- (폐동맥 폐쇄증 (Pulmonary atresia)의 외과적 치료 -2예 보고-)

  • 강경훈
    • Journal of Chest Surgery
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    • v.19 no.3
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    • pp.464-469
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    • 1986
  • Pulmonary atresia with intact ventricular septum, and with VSD were uncommon congenital anomalies with high mortality in the neonatal period. Those survivals depend on an adequate interatrial communication or interventricular communication and pulmonary flow via large aortopulmonary collateral including PDA. Recently we experienced surgical correction of 2 cases pulmonary atresia with intact ventricular septum and with VSD. On case 1, 10-years old male patient was confirmed as pulmonary valvular membranous atresia with intact ventricular septum combined with large functioning PFO and mild tricuspid incompetence. So we performed total correction under the E.C.C, that was PDA ligation, RVOT reconstruction with monocusp valved outflow patch [16mm], repair of tricuspid insufficiency and closure of PFO. Post-operative hemodynamic result was good and there was no event during hospital course. On case 2, 16-years old female patient was diagnosed as pulmonary atresia with VSD and PDA. MPA was absent, remained fibrous cord like remnant and type of VSD was subaortic defect [3cm by 3cm in the size]. PDA was located at the usual site. Under the E.C.C. VSD patch closure through the right ventriculotomy, anastomosis between the right ventricular outflow tract and the pulmonary bifurcated site with the extra-cardiac Hancock valved conduit [22cm] and PDA ligation were performed.

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Pulmonary Thromboendanterectomy of Chronic Pulmonary Thromboembol ism -A case Report- (만성 폐색전증의 색전제거술 -치험 1례 보고-)

  • 신윤철;지현근
    • Journal of Chest Surgery
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    • v.29 no.5
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    • pp.569-572
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    • 1996
  • A sixty nine-year-old mate patient was admitted with a chief complaint of exertional dyspnea. Lung perfusion scan revealed total perfusion defect of the of left lung and CT anglography showed the ab- rupt cutoff left pulmonary artery. He denied of trauma history, previous lower leg symptom and sign, or any embolic history. With the impression of chronic pulmonary thromboembolism of unknown etiology, operation was done under the cardiopulmonary bypass through a median sternotomy. After main pulmonary artery clamping and pulmonary arteriotomy, thromboembolectomy was done. Postoperative lung perfusion scan and CT angiography showed near normal left pulmonary blood flow. The patient was discharged on the postoperative 9th day without any postoperative complication.

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Effect of Hydrogen on Mechanical S tability of Amorphous In-Sn-O thin films for flexible electronics (수소 첨가에 의한 비정질 ITO 박막의 기계적 특성 연구)

  • Kim, Seo-Han;Song, Pung-Geun
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2018.06a
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    • pp.56-56
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    • 2018
  • Transparent conductive oxides (TCOs) have attracted attention due to their high electrical conductivity and optical transparency in the visible region. Consequently, TCOs have been widely used as electrode materials in various electronic devices such as flat panel displays and solar cells. Previous studies on TCOs focused on their electrical and optical performances; there have been numerous attempts to improve these properties, such as chemical doping and crystallinity enhancement. Recently, due to rapidly increasing demand for flexible electronics, the academic interest in the mechanical stability of materials has come to the fore as a major issue. In particular, long-term stability under bending is a crucial requirement for flexible electrodes; however, research on this feature is still in the nascent stage. Hydrogen-incorporated amorphous In-Sn-O (a-ITO) thin films were fabricated by introducing hydrogen gas during deposition. The hydrogen concentration in the film was determined by secondary ion mass spectrometry and was found to vary from $4.7{\times}10^{20}$ to $8.1{\times}10^{20}cm^{-3}$ with increasing $H_2$ flow rate. The mechanical stability of the a-ITO thin films dramatically improved because of hydrogen incorporation, without any observable degradation in their electrical or optical properties. With increasing hydrogen concentration, the compressive residual stress gradually decreased and the subgap absorption at around 3.1 eV was suppressed. Considering that the residual stress and subgap absorption mainly originated from defects, hydrogen may be a promising candidate for defect passivation in flexible electronics.

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Design of Preform in the Forging Process of the Ball-Joint Socket (볼조인트 소켓 단조 공정의 예비형상 설계)

  • Park C. H.;Lee S. R.;Shin H. K.;Yang D. Y.;Park Y. B.;Ahn B. G.;Kim Y. H.;Bae M. H.;Chung S. C.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2001.10a
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    • pp.224-227
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    • 2001
  • The preform design in metal forging plays a key role in improving product quality, such as ensuring defect-free property and proper metal flow. In industry, preforms are generally designed by the iterative trial-and-error approach, but this approach leads not only to significant tool cost but also to the down-time of the production equipment. It is thus necessary to reduce the time and the man-power through an effective method of perform design. In this paper, the equi-potential lines designed in the electric field are introduced to find the preform shape. The equi-potential lines obtained by the arrangement of the initial and final shapes are utilized for the design of the preform, and then applied for obtaining a fine preform in the foging process of the ball-joint socket.

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FEM Analysis on Cavity Closure Behavior during Hot Open Die Forging Process (열간 자유단조시 내부 공극 압착 거동에 관한 유한요소해석)

  • Lee, Y.S.;Kwon, Y.C.;Kwon, Y.N.;Lee, S.W.;Kim, N.S.;Lee, J.H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2007.10a
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    • pp.50-52
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    • 2007
  • Large size forged parts usually were made by hot open die forging because of the die cost, high applied load and small manufacturing quantities. Cast ingots were used in open die forging and the ingots almost included the cavities in its inside. Therefore, one of the aims for forging processes is to close and remove the cavities. However, its criteria were well not defined since the studies have many difficulties to investigate the cavity behaviors because of its large size. In this study, the cavity closure behavior was investigated by experimental and FE analysis. The FEM analysis is performed to investigate the overlap defect of cast ingots during free forging stage. The measured flow stress data were used to simulate the forging process of cast ingot using the practical material properties. Also the analysis of cavity closure is performed by using the $DEFORM^{TM}$-3D. The calculated results of cavity closure behavior are compared with the measured results before and after forging, which are scanned by the X-ray scanner. From this result, the criteria for deformation amounts effect on the cavity closure can be investigated by the comparison between practical experiment and numerical analysis.

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Treatment Using a Single-Lobed Rotation Flap in Diabetic Forefoot Ulceration: Five Case Reports (단일엽 회전 피판술을 이용한 당뇨병성 전족부 궤양의 치료: 5예 보고)

  • Kim, Jun-Beom;Lee, Bong-Ju;Kim, Cheol-U;Jung, Deukhee
    • Journal of Korean Foot and Ankle Society
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    • v.23 no.4
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    • pp.208-211
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    • 2019
  • Diabetic foot ulcers can progress to the point where amputation is needed, and so these ulcers require active treatment. Skin grafts or flaps can be performed for coverage of this type of ulcer. Local flap surgery is relatively easy to perform and good results have been previously reported. We performed single-lobed rotation flap on 5 cases of forefoot ulcer around the site of weight bearing. The location of the foot ulcers was the medial part of the first metatarsophalangeal joint in all the patients. The mean size of the defect was 4.70 ㎠. Managing of ulcers, controlling of diabetes and infection, and improving of peripheral blood flow were performed before surgery. In two cases, infection progressed to the articular cartilage and so metatarsophalangeal joint fusions were performed simultaneously. All the cases were completely transplanted. There was no recurrence of the ulcers, and all the patients were able to walk.

A Study on the Characteristics of Machining for AC8A-T6 Aluminum Alloy (AC8A-T6 알루미늄 합금재의 절삭가공 특성에 관한 연구)

  • 최현민;김경우;김우순;김용환;김동현;채왕석
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2002.10a
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    • pp.192-197
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    • 2002
  • In this study, examined the cutting characteristics of alumuminum alloy AC8A-T6 that is used to present car piston materials. And in been holding materials machining empirically escape as result that experiment comparison changing the cutting speed and feed on various condition to choose efficient machining condition. The following results can be summarized from this research. 1. As the cutting speed decreased, principal cutting force and thrust cutting force is increased, and reason that cutting force interacts greatly in the low cutting speed is thought by result by BUE's stabilization. 2. The feed speed and cutting speed increase, friction factor is decrescent and the cause appeared the thrust cutting force is fallen than cutting force relatively because chip flow according to increase of the feed rate is constraint. 3. Though specific cutting resistance grows cutting area and the feed rate are few, the cause was expose that shear angle decreases by rake face of tool gets into negative angle remarkably as wear of a cutting tool or defect part of workpiece is cut. 4. Cutting speed do greatly depth of cut is slow, surface roughness examined closely through an experiment that becomes bad, and know that it can get good surface that process cutting speed because do feed rate by 0.1mm/rev low more than 250m/min to get good surface roughness can.

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