• Title/Summary/Keyword: Re-circulation

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The Effect of Antenna Pattern Measurement According to Radio Wave Environment on Data Quality of HF Ocean Radar (전파환경에 따른 안테나패턴 측정(APM) 결과가 고주파 해양레이더의 자료 품질에 미치는 영향)

  • Jae Yeob, Kim;Dawoon, Jung;Seok, Lee;Kyu-Min, Song
    • Ocean and Polar Research
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    • v.44 no.4
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    • pp.287-296
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    • 2022
  • High-frequency (HF) radar measures sea surface currents from the radio waves transmitted and received by antenna on land. Since the data quality of HF radar measurements sensitively depend on the radio wave environment around antenna, Antenna Pattern Measurements (APM) plays an important role in evaluating the accuracy of measured surface currents. In this study, APM was performed by selecting the times when the background noise level around antenna was high and low, and radial data were generated by applying the ideal pattern and measured pattern. The measured antenna pattern for each case was verified with the current velocity data collected by drifters. The radial velocity to which the ideal pattern was applied was not affected by the background noise level around antenna. However, the radial velocity obtained with APM in the period of high background noise was significantly lower in quality than the radial velocity in a low noise environment. It is recomended that APM be carried out in consideration of the radio wave environment around antenna, and that the applied result be compared and verified with the current velocity measurements by drifters. If it is difficult to re-measure APM, we suggest using radial velocity in generating total vector with the ideal pattern through comparative verification, rather than poorly measured patterns, for better data quality.

Circulation Dynamics to Improve Commercial Activity in a Mega Mall

  • Kwun, Joon-Bum;Kim, Duk-Su
    • Architectural research
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    • v.15 no.4
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    • pp.183-190
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    • 2013
  • The 'one-day-shopping' concept that we experience today in a modern mega mall changed the propensity to consume compared to the past. The idea of a mega mall originated in the U.S. and the first suburban shopping malls as we know them today were built in the 1950s. The convenience of these malls had a great impact not only on consumers but also on the retail industry in general and the new mega mall idea has since spread around the world, with the largest ones located in China and Southeast Asia. Meanwhile, Korea had the fastest-growing economy during the last three decades and with that boom the compositional structure of domestic retail facilities became extremely diverse. Today, there are 36 new mega mall development plans to be completed before 2016, which represent a rapid and dynamic change in consumerism lifestyle in Korea. In this regard, this study will re-evaluate the first mega mall in Korea, the COEX Mall, and identify initial errors regarding its circulation plan and provide an ideal design strategy for future commercial mega malls based on literature review and comparison analysis.

Digital Library in the Notion of Publishing, II : Practical Design of the Hybrid Digital Library (출판기능이 부여된 디지털도서관 II - 하이브리드 디지털도서관의 모형 설계 -)

  • Chung, Jun Min
    • Journal of the Korean BIBLIA Society for library and Information Science
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    • v.25 no.4
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    • pp.109-128
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    • 2014
  • A digital library could be understood as not a part of information cycling, but whole process of information production, circulation and reproduction. This study suggests that a digital library should be a creator as which it is publishing, circulating, and re-producing the information resources. Therefore, the role of intrinsic DRM (Digital Resources Management) can be interpreted as a digital library. Open access model have been already adopted to many university libraries, many university libraries are publishing free access online research resources by themselves. Also, research collection based on cloud computing can be extended to networked research collection and share with other university libraries. These evidences show future library can be the digital library with online and open accessible publishing function.

An Analysis of Residents' Perception on District Heating in the Village Unit Using Forest Biomass - Focused on the Case of Forest Carbon Circulation Village in Hwacheon - (산림바이오매스 이용 마을단위 지역난방에 관한 주민 인식 분석 - 화천 산림탄소순환마을 사례를 중심으로 -)

  • Ryu, Sun-Hwa;Kim, Seong-Hak
    • Journal of Environmental Science International
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    • v.29 no.4
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    • pp.339-349
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    • 2020
  • This study aims to identify participating resident awareness of the improvements to forest carbon cycle villages created by the Korea Forest Service by introducing a system for district heating basedon forest biomass in mountainous areas. Hwacheon Forest Carbon Circulation village was established in Paroho-neureup village in Yuchon-ri, Hwacheon-gun between 2011 and 2013. However, its operation has not been smooth due to the increasing number of households rapidly leaving the district heating system. This study surveyed 76 households that participated in the district heating system using forest biomass in the early stages of the project. This includes households participating in the district heating system(participating households) and households not currently participating in the district heating system(withdrawal households) from September 2019. Surveys focused on the process of participating in forest carbon cycle village projects, and satisfaction in local heating and policy requirements. Of the 67 households, excepting those not allowed to participate in the survey due to death or having moved elsewhere, 36 households participated and 31 households the were in the process of leaving the village were also included. As a result, there was a significant difference between participating and exiting households in the motivation and satisfaction level of district heating. The results of this study are expects to reflect the importance of awareness of residents in the operation of the forest carbon cycle village. This will be utilized as an important dataset for improvement as a means to promote the re-entry if outgoing households. It will also help set the direction of the forest town revitalization project, utilizing forest biomass in the future.

Hemodynamic Characteristics Affecting Restenosis after Percutaneous Transluminal Coronary Angioplasty with Stenting in the Angulated Coronary Stenosis

  • Lee, Byoung-Kwon;Kwon, Hyuck-Moon;Roh, Hyung-Woon;Cho, Min-Tae;Suh, Sang-Ho
    • International Journal of Vascular Biomedical Engineering
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    • v.1 no.1
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    • pp.13-23
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    • 2003
  • Backgrounds: The present study in angulated coronary stenosis was to evaluate the influence of velocity and wall shear stress (WSS) on coronary atherosclerosis, the changes of hemodynamic indices following coronary stenting, as well as their effect of evolving in-stent restenosis using human in vivo hemodynamic parameters and computed simulation quantitatively and qualitatively. Methods: Initial and follow-up coronary angiographies in the patients with angulated coronary stenosis were performed (n=80). Optimal coronary stenting in angulated coronary stenosis had two models: < 50 % angle changed(model 1, n=43), > 50% angle changed group (model 2, n=37) according to percent change of vascular angle between pre- and post-intracoronary stenting. Flow-velocity wave obtained from in vivo intracoronary Doppler study data was used for in vitro numerical simulation. Spatial and temporal patterns of velocity vector and recirculation area were drawn throughout the selected segment of coronary models. WSS of pre/post-intracoronary stenting were calculated from three-dimensional computer simulation. Results: Follow-up coronary angiogram demonstrated significant difference in the percent of diameter stenosis between two groups (group 1: $40.3{\pm}30.2$ vs. group 2: $25.5{\pm}22.5%$, p<0.05). Negative WSS area on 3D simulation, which is consistent with re-circulation area of velocity vector, was noted on the inner wall of post-stenotic area before stenting. The negative WSS was disappeared after stenting. High spatial and temporal WSS before stenting fell into within physiologic WSS after stenting. This finding was prominent in Model 2 (p<0.01) Conclusions: The present study suggests that hemodynamic forces exerted by pulsatile coronary circulation termed as WSS might affect on the evolution of atherosclerosis within the angulated vascular curvature. Moreover, geometric change, such as angular difference between pre / post-intracoronary stenting might give proper information of optimal hemodynamic charateristics for vascular repair after stenting.

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Flow Visualization in Realistic Arterial Bypass Graft Model

  • Singh, Megha;Shin, Se-Hyun
    • International Journal of Vascular Biomedical Engineering
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    • v.3 no.1
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    • pp.1-5
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    • 2005
  • Background: Coronary atherosclerosis artery disease is the leading cause of morbidity and mortality. Coronary artery bypass grafting (CABG) which utilizes the saphenous vein graft, has helped in alleviating the suffering of these patients. Newer techniques are being developed to improve upon the techniques. Still there is significant number of failures, leading to re-grafting or re-vascularization. Some studies have helped in identifying the high and low shear stress regions. Further studies based on their realistic models are required. Material, methods and results: we developed the realistic model of fully blocked right coronary with bypass graft placed at angle of $5^0$ with curvature similar to that of artery. Pulsatile flow of birefringent solution through this model by polarized light was visualized. The images of complete flow field in the model were recorded and analyzed. Regions of high flow disturbances which are prone to further changes are identified. Existence of recirculation in the blocked coronary may initiate new blood-tissue interactions deleterious to bypass graft. Conclusion: Our study shows that by selecting the procedure to place bypass graft at minimum angle with curvature similar to that of artery and smooth sutures may improve the life span of the graft. This study also identified that coronary blocked regions contributing by recirculation flow at the proximal and distal regions of bypass which may require further studies.

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A Facial Chuna Manual Therapy for Peripheral Facial Nerve Palsy

  • Park, Yu-Kyeong;Lee, Cho In;Lee, Jung Hee;Lee, Hyun-Jong;Lee, Yun-kyu;Seo, Jung-Chul;Kim, Jae Soo
    • Journal of Acupuncture Research
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    • v.36 no.4
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    • pp.197-203
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    • 2019
  • The purpose of this study was to investigate useful manual therapy techniques for peripheral facial nerve palsy and to propose guidelines to be applied for current manual therapy techniques. Several databases were searched to find manual therapies for facial palsy. These therapies included cervical, and temporomandibular joint chuna manual therapy, proprioceptive neuromuscular facilitation, neuromuscular re-education, facial exercise, and mime therapy. Both cervical, and temporomandibular joint chuna manual therapy release nerve compression, helping blood circulation and nerve conduction. Proprioceptive neuromuscular facilitation uses irradiation, bilateral activation, and eccentric facilitation to improve muscle power and symmetry. Neuromuscular re-education, as a retraining tool for facial movement patterns, enhances neuromuscular feedback. Facial exercise helps the patient continuously move and massage facial muscle themselves. Mime therapy aims to develop a conscious connection between the use of certain muscles and facial expressions. The use of facial chuna manual therapy for peripheral facial nerve palsy can stimulate the proprioceptive neuromuscular receptors in the face. Peripheral facial nerve palsy has 4 phases; progress phase, plateau phase, recovery phase, and sequelae phase. Each phase needs different treatments which include relaxation, assistance, resistance, origin-insertion extension, and nerve pathway expansion.

Monitoring of Heparin and Protamine Therapy by Activated Clotting Time During Open-Heart Surgery (개심술시 Activated Clotting Time 을 이용한 Heparin 및 Protamine 양 조절에 관한 임상적 관찰)

  • Kim, Chun-Dong;Lee, Sung-Haing
    • Journal of Chest Surgery
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    • v.13 no.4
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    • pp.346-355
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    • 1980
  • It has been proposed that wide individual variation in response to heparin be not considered in the conventional set protocol for the control of heparin and protamine during extracorporeal circulation. In this paper, two protocol of heparin and protamine therapy were compared to assess the role of the Activated Clotting Time [ACT] in relation to heparin, protamine, and postoperative blood loss and transfusion. The study groups consisted of the 31 patients [adults 15 and children 16] anticoagulated with the conventional heparin protocol and the 31 patients [adults 15 and children 16] anticoagulated with ACT protocol during extracorporeal circulation. In the conventional heparin protocol, two mg of heparin per kg was administered initially with an additional 0.75 mg of heparin per kg every 30 minutes of extracorporeal circulation, and reversal was accomplished with protamine in a dose of 1.5 times the total milligram of heparin. In the ACT protocol, two mg of heparin per kg was administered initially with an additional dose of heparin enough to reach an ACT of 480 seconds [within safe zone 300 to 600 seconds] from the patient`s dose response curve every 1 hour of extracorporeal circulation, and reversal was done with protamine in a dose of 1.3 times the milligram of the residual heparin. The results were summarized as follows. After a dose of 2 mg per kg of heparin, the patient`s ACT varied from 240 to 600 seconds in adults and from 240 t~ 660 seconds in children. In the ACT group the total amount of heparin administered was markedly reduced when compared to the conventional group, and less protamine was required to neutralize heparin. The dose of heparin administered decreased from 7.07 [SE 0.42] mg/kg of the conventional group to 4.92 [SE 0.32] mg/k8 of the ACT group in adults and from 10.17 [SE 1.15] mg/kg to 5.23 [SE 0.24] mg/kg in children, which represent 30.4% and 48.6% decrease respectively. The dose of protamine administered for reversal decreased from 10.6 [SE 0.63] mg/kg of the conventional group to 3.35 [SE 0.35] mg/kg of the ACT group in adults and from 15.7 [SE 1.70] mg/kg to 3.26 [SE 0.27] mg/kg in children, which represent 68.4% and 79.2% respectively. The ratio of protamine to heparin administered in the conventional group was 1.50:1 in adults and 1.54:1 in children, but in the ACT group 0.68:1 in adults and 0.62:1 in children. Postoperative blood loss and transfusion revealed no statistically significant difference between the two groups. Although six patients in the conventional group and one in the ACT group needed re-exploration for continuous hemorrhage, no case of generalized oozing was encountered, and in each case a definite bleeding site was identified. Author would like emphasizing the value of the ACT protocol in controlling heparin and protamine administration during extracorporeal circulation.

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Studies on Changes in the Hydrography and Circulation of the Deep East Sea (Japan Sea) in a Changing Climate: Status and Prospectus (기후변화에 따른 동해 심층 해수의 물리적 특성 및 순환 변화 연구 : 현황과 전망)

  • HOJUN LEE;SUNGHYUN NAM
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.28 no.1
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    • pp.1-18
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    • 2023
  • The East Sea, one of the regions where the most rapid warming is occurring, is known to have important implications for the response of the ocean to future climate changes because it not only reacts sensitively to climate change but also has a much shorter turnover time (hundreds of years) than the ocean (thousands of years). However, the processes underlying changes in seawater characteristics at the sea's deep and abyssal layers, and meridional overturning circulation have recently been examined only after international cooperative observation programs for the entire sea allowed in-situ data in a necessary resolution and accuracy along with recent improvement in numerical modeling. In this review, previous studies on the physical characteristics of seawater at deeper parts of the East Sea, and meridional overturning circulation are summarized to identify any remaining issues. The seawater below a depth of several hundreds of meters in the East Sea has been identified as the Japan Sea Proper Water (East Sea Proper Water) due to its homogeneous physical properties of a water temperature below 1℃ and practical salinity values ranging from 34.0 to 34.1. However, vertically high-resolution salinity and dissolved oxygen observations since the 1990s enabled us to separate the water into at least three different water masses (central water, CW; deep water, DW; bottom water, BW). Recent studies have shown that the physical characteristics and boundaries between the three water masses are not constant over time, but have significantly varied over the last few decades in association with time-varying water formation processes, such as convection processes (deep slope convection and open-ocean deep convection) that are linked to the re-circulation of the Tsushima Warm Current, ocean-atmosphere heat and freshwater exchanges, and sea-ice formation in the northern part of the East Sea. The CW, DW, and BW were found to be transported horizontally from the Japan Basin to the Ulleung Basin, from the Ulleung Basin to the Yamato Basin, and from the Yamato Basin to the Japan Basin, respectively, rotating counterclockwise with a shallow depth on the right of its path (consistent with the bottom topographic control of fluid in a rotating Earth). This horizontal deep circulation is a part of the sea's meridional overturning circulation that has undergone changes in the path and intensity. Yet, the linkages between upper and deeper circulation and between the horizontal and meridional overturning circulation are not well understood. Through this review, the remaining issues to be addressed in the future were identified. These issues included a connection between the changing properties of CW, DW, and BW, and their horizontal and overturning circulations; the linkage of deep and abyssal circulations to the upper circulation, including upper water transport from and into the Western Pacific Ocean; and processes underlying the temporal variability in the path and intensity of CW, DW, and BW.

Surgical Treatment of Vascular Complications after Microvascular Surgery (미세혈관수술 후 발생한 혈류장애의 수술적 처치)

  • Kim, Jung Hyun;Kim, Jin Soo;Lee, Dong Chul;Ki, Sae Hwi;Roh, Si Young;Yang, Jae Won
    • Archives of Plastic Surgery
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    • v.32 no.4
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    • pp.461-466
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    • 2005
  • Despite the major advances in the microvascular surgery with success rates of up to 98%, failure and vascular complications still remain even in the experienced hands. Failure of blood to flow across an anastomosis is usually caused by three factors: (1) Technical errors; (2) Undetected damage more proximally or via vasospasm; or (3) A clot or a thrombus. The success of a microvascular surgery depends on the severity of the vascular injury and, proper debridement of an injured vessel, and the failure rate of microvascular anastomosis in cases of trauma is higher as the thrombogenic possibility is increased by the endothelial damage. From January to November in 2003, 460 patients were underwent microvascular surgery(270 replantations and 190 free flap transfers) and re-operations were performed in 15 cases. Cases were reviewed by clinical and operative records. In these cases, causes of post-operative circulation insufficiency were identified as 9 vascular spasms and 6 thromboses at the previous anastomotic site. The average of re-operative success rate was 73%(60% in replantations and 100% in free flaps). In conclusion, through precise postoperative monitoring and assessment, immediate surgical re-exploration could be performed when a vascular complication is suspicious, the success rate of microvascular surgery would be increased more.