• 한국연소학회지
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• 제9권3호
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• pp.19-26
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• 2004

This paper presents results of experimental study of flame chemiluminescence from turbulent premixed flames in a dump combustor. A detailed spectroscopic measurement of chemiluminescence over the wavelength of 405-495 nm is made for various flow conditions. No effect of turbulence on the relationship between chemiluminescence and heat release is found, suggesting the overall chemiluminescence intensity collected be used as a measure of overall heat release for non-oscillating stable flame. The background-$CO_2^*$ subtracted $CH^*$ chemiluminescence is found to be more sensitive to the equivalence ratio and premixedness of fuel-air mixture than $CO_2^*$ chemiluminescence.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2010년도 춘계학술대회 논문집
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• pp.232-236
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• 2010

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2009년도 학술대회 초록집
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• pp.129-129
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• 2009

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2003년도 제20회 춘계학술대회 논문집
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• pp.1-1
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• 2003

No Abstract, See Full Text

• E2M - 전기 전자와 첨단 소재
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• 제11권2호
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• pp.149-152
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• 1998

• 대한두개안면성형외과학회지
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• 제21권4호
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• pp.229-236
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• 2020

Background: Oncologic resection of the scalp confers several obstacles to the reconstructive surgeon dependent upon patient-specific and wound-specific factors. We aim to describe our experiences with various reconstructive methods, and delineate risk factors for coverage failure and complications in the setting of scalp reconstruction. Methods: A retrospective chart review was conducted, examining patients who underwent resection of fungating scalp tumors with subsequent soft-tissue reconstruction from 2003 to 2019. Patient demographics, wound and oncologic characteristics, treatment modalities, and outcomes were recorded and analyzed. Results: A total of 189 patients were appropriate for inclusion, undergoing a range of reconstructive methods from skin grafting to free flaps. Thirty-three patients (17.5%) underwent preoperative radiation. In all, 48 patients (25.4%) suffered wound site complications, 25 (13.2%) underwent reoperation, and 47 (24.9%) suffered from mortality. Preoperative radiation therapy was an independent risk factor for wound complications (odds ratio [OR], 2.85; 95% confidence interval [CI], 1.1-7.3; p=0.028) and reoperations (OR, 4.45; 95% CI, 1.5-13.2; p=0.007). Similarly, the presence of an underlying titanium mesh was an independent predictor of wound complications (OR, 2.49; 95% CI, 1.1-5.6; p=0.029) and reoperations (OR, 3.40; 95% CI, 1.2-9.7; p=0.020). Both immunosuppressed status (OR, 2.88; 95% CI, 1.2-7.1; p=0.021) and preoperative radiation therapy (OR, 3.34; 95% CI, 1.2-9.7; p=0.022) were risk factors for mortality. Conclusion: Both preoperative radiation and the presence of underlying titanium mesh are independent risk factors for wound site complications and increased reoperation rates following oncologic resection and reconstruction of the scalp. Additionally, preoperative radiation, along with an immunosuppressed state, may predict patient mortality following scalp resection and reconstruction.

• Journal of Gastric Cancer
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• 제17권4호
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• pp.306-318
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• 2017

Purpose: Guidelines in Western countries recommend retrieving ${\geq}15$ lymph nodes (LNs) during gastric cancer resection. This study sought to determine whether the number of examined lymph nodes (eLNs), a proxy for lymphadenectomy, effects survival in node-negative disease. Materials and Methods: The US National Cancer Database (2003-2011) was reviewed for node-negative gastric adenocarcinoma. Treatment was categorized by neoadjuvant therapy (NAT) vs. initial resection, and further stratified by eLN. Kaplan-Meier and Weibull models were used to analyze overall survival. Results: Of the 1,036 patients who received NAT, 40.5% had ${\leq}10eLN$, and most underwent proximal gastrectomy (67.8%). In multivariate analysis, greater eLN was associated with improved survival (eLN 16-20: HR, 0.71; P=0.039, eLN 21-30: HR, 0.55; P=0.001). Of the 2,795 patients who underwent initial surgery, 42.5% had ${\leq}10eLN$, and the majority underwent proximal gastrectomy (57.2%). In multivariate analysis, greater eLN was associated with improved survival (eLN 11-15: HR, 0.81; P=0.021, eLN 16-20: HR, 0.73; P=0.004, eLN 21-30: HR, 0.62; P<0.001, and eLN >30: HR, 0.58; P<0.001). Conclusions: In the United States, the majority of node-negative gastrectomies include suboptimal eLN. In node-negative gastric cancer, greater LN retrieval appears to have therapeutic and prognostic value, irrespective of initial treatment, suggesting a survival benefit to meticulous lymphadenectomy.

• 대한기계학회논문집B
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• 제22권7호
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• pp.1022-1029
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• 1998

The relation of the inlet fuel distribution, velocity, and overall equivalence ratio to the stability of a lean burning no-swirl dump combustor was examined. Premixed or partially premixed natural gas was introduced into the air stream, which flowed to the dump region through an annular inlet pipe. Inlet air was preheated upto 400 deg.C. Combustion instability was observed to occur at higher value of equivalence ratio (> 0.6) as the degree of unpremixedness was increased. Instabilities exhibited a dominant frequency of ~ 500 Hz, which corresponded to a half wave mode of combustor. CH chemiluminescence and pressure fluctuations were in-phase when combustion instabilities occurred. Acetone LIF images revealed that there was a strong fuel concentration gradient across the inlet annulus. Phase resolved OH LIF images showed that inlet fuel distribution was affected by the combustion instabilities.

• ETRI Journal
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• 제30권2호
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• pp.194-204
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• 2008

The online collection of coarse-grained traffic information, such as the total number of flows, is gaining in importance due to a wide range of applications, such as congestion control and network security. In this paper, we focus on an active queue management scheme called SRED since it estimates the number of active flows and uses the quantity to indicate the level of congestion. However, SRED has several limitations, such as instability in estimating the number of active flows and underestimation of active flows in the presence of non-responsive traffic. We present a Markov model to examine the capability of SRED in estimating the number of flows. We show how the SRED cache hit rate can be used to quantify the number of active flows. We then propose a modified SRED scheme, called hash-based two-level caching (HaTCh), which uses hashing and a two-level caching mechanism to accurately estimate the number of active flows under various workloads. Simulation results indicate that the proposed scheme provides a more accurate estimation of the number of active flows than SRED, stabilizes the estimation with respect to workload fluctuations, and prevents performance degradation by efficiently isolating non-responsive flows.

• Journal of Computing Science and Engineering
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• 제9권4호
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• pp.163-176
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• 2015

Self-organization of distributed wireless sensor nodes is a critical issue in wireless sensor networks (WSNs), since each sensor node has limited energy, bandwidth, and scalability. These issues prevent sensor nodes from actively collaborating with the other types of sensor nodes deployed in a typical heterogeneous and somewhat hostile environment. The automated self-organization of a WSN becomes more challenging as the number of sensor nodes increases in the network. In this paper, we propose a dynamic self-organized architecture that combines tree topology with a drawn-grid algorithm to automate the self-organization process for WSNs. In order to make our proposed architecture scalable, we assume that all participating active sensor nodes are unaware of their primary locations. In particular, this paper presents two algorithms called active-tree and drawn-grid. The proposed active-tree algorithm uses a tree topology to assign node IDs and define different roles to each participating sensor node. On the other hand, the drawn-grid algorithm divides the sensor nodes into cells with respect to the radio coverage area and the specific roles assigned by the active-tree algorithm. Thus, both proposed algorithms collaborate with each other to automate the self-organizing process for WSNs. The numerical and simulation results demonstrate that the proposed dynamic architecture performs much better than a static architecture in terms of the self-organization of wireless sensor nodes and energy consumption.