• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.5
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• pp.938-946
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• 1989

Using the CT specimen of carbon steel(SM45C), we estimated the fatigue crack propagation behavior in stable crack propagation range. Furthermore the fatigue crack propagation rate, Acoustic Emission(AE) count rate, and fractography characteristics were also compared among others. The following results were confirmed by experimental observation. Near-threshold stress intensity factor range(.DELTA. $K_{th}$) is influenced by stress ratio but not at the upper limit of stable crack propagation range. As stress intensity factor range(.DELTA.K) and(or) stress amplitude increase (s), both crack propagation rate(da/dN) and AE count rate(dn/dN) increase. Effective stress intensity factor range(.DELTA. $K_{off}$) determined from the crack closure point measurement by AE method is useful for the evaluation of fatigue crack propagation rate. Fractography in stable crack propagation range showed striation, and agreed with the crack propagation rate obtained either by experiment of by the results of microscopic measurements.s.

• The Korean Journal of Nuclear Medicine
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• v.22 no.2
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• pp.193-197
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• 1988

Measurement of gastric emptying rate has been performed by a variety of techniques. Nuclear medicine method is a major advance in the quantitative evaluation of gastric function and also of pharmacologic intervention. Normal gastric emptying rate was measured in 48 healthy volunteers using live chicken liver labeled with $^{99m}Tc-Tin$ Colloid as a solid phase marker. In vitro studies were performed to evaluate the labeling efficiency and stability in hydrochloric acid and in human gastric juice of intracellularly labeled chicken liver. Anterior image counts only were compared with the geometric mean of anterior and posterior counts in 12 healthy volunteers who were studied by both anterior count and posterior count. The results were as follows: 1) The labeling efficiency in gastric juice and hydrochloric acid were $95.5{\pm}1.23%,\;95.7{\pm}1.15%$, respectively. 2) Half gastric emptying time by anterior count only was $126{\pm}21$ minutes 3) Although standard deviation of geometric mean method was smaller than anterior count method, gastric emptying curves from both method were similar. In daily practice, anterior count method may be useful alternative to geometric mean method in evaluation of gastric emptying rate.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.3
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• pp.561-566
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• 2011

In EPCglobal Class-1 Gen-2 RFID system, a slot-count selection algorithm has been proposed to determine the slot-count size depending on the status of reply slot. In the slot-count selection algorithm of Gen-2, the slot-count value is increased or decreased by the weight C, which is identical and independent of the slot status. It has an advantage that the algorithm is simple, but it is difficult to maintain an optimal slot-count size. Therefore, in this paper, we propose an adaptive slot-count selection algorithm, which applies the parameter C differently based on the result of tag replies. Through simulations, it is demonstrated that the collision rate for the proposed scheme is about 42% and 65% lower than the schemes proposed by Wang and Gen-2. Therefore, the adaptive slot-count selection algorithm achieves faster tag identification time compared with the existing algorithms due to the low collision rate.

• Journal of the Korea Furniture Society
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• v.10 no.2
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• pp.73-78
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• 1999

This paper describes the relationship between the bending strength properties of sloped finger-jointed woods and the acoustic emissions(AEs) generated during the test. Rhus verniciflua pieces were cut in sloped-finger types and glued with three kinds of adhesives(polyvinyl acetate, polyvinyl-acryl acetate and oilic urethane resin). The slope ratios of finger joints were 0, 1.0, 1.5, and 2.0. The AE cumulative event count and cumulative count were measured during the bending test. The results were as follows: The lower the bending strength(load) was, the generation time of AE event count got and the higher the increasing rate of AE event count became in the sloped finger-jointed specimens bonded with polyvinyl acetate, polyvinyl-acryl acetate oilic urethane resin adhesives. Therefore, the slope from load-AE cumulative event count was very steep. The patterns of AE event count and count were very similar. The relationship between the MOR and the AE parameter from load and AE cumulatve event count in the early stage of the sloped finger-jointed specimens bonded with polyvinyl acetate, polyvinyl-acryl and oilic urethane resin adhesives was much greater than that between the MOE and the MOR. Therefore, the AE signals obtained during bending test are useful for estimating the strength of sloped finger-jointed Rhus verniciflua specimens.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.10
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• pp.41-46
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• 2003

This paper deals with the possibility of tap breakage detection by AE sensor. AE signals in the tapping were not seldom generated in low speed but reflected the tapping process exactly in high speed. Using AE raw signals sampled in 500kHz, AE RMS and AE count rate was computed in software. When the converting time of AE RMS is less than 10ms, we could distinguish between normal cutting and tap breakage. And AE count rate was more exact when the converting time is greater than 1ms. When two methods were compared to each other, AE count rate was more accurate.

• The Journal of Pediatrics of Korean Medicine
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• v.12 no.1
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• pp.257-276
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• 1998

Introduction The effects of Samchulkunbitang on the immunosuppression induced by methotrexate in rats were investigated in this experument. The multiple parameters of immunity assessed in each rats includes the rate of body weight loss, weight changes in thymus, spleen and axillary lymphnode. The number of lymphocytes and CD4+ T cell count in the blood, thymus, spleen and axillary lymphnode were also measured. Methodology Male Sprague-Dawley rats were chosen as an experiment object and were divided into 4 groups by a random selection. Each group consisted of 6 rats. The normal group didn't receive any treatment. The control group was administered with methotrexate for 5 days. The sample Ⅰ group was administered with Samchulkunbitang for 5 days. The sample Ⅱ group was administered with both Samchulkunbitang and methotrexate for 5 days. The dosage of medication was 2cc/day, 1cc given at 10 AM and another 1cc given at 5 PM. Results The rate of body weight loss was significantly increased in the Sample Ⅰ and Sample Ⅱ group. The weight of thymus and spleen were significantly increased in Sample Ⅰ and Sample Ⅱ groups While the weight of axillary lymphnode did not show much increase. No significant differences were measured among the experimental groups. Blood lymphocyte count, blood CD4+ T cell count, spleen lymphocyte count, axillary lymphnode lymphocyte and CD4+ T cell count were significantly increased in Sample Ⅰ and Sample Ⅱ groups while spleen CD4+ T cell count did not show much increase. No significant differences were measured among the experimental groups. Conclusion As one can witness from the above results, administration of Samchulkunbitang played potent role in increasing immune system among the rats treated with methotrexate which induces immunosuppression. Overall increase of lymphocyte count and CD4+ T cell count in the sample groups with Samchulkunbitang effectively proves its ability to boost the immune system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.2B
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• pp.203-209
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• 2004

In OBS networks, the burst dropping due to contention significantly affects the performance of TCP, but existing drop policies have not considered this problem and researches related to TCP have been mainly studied on burst assembling. We propose the drop policy considering retransmission of TCP to improve the performance of TCP in OBS networks. The proposed drop policy is the Retransmission Count-based DP that regards retransmission count of bursts as priority when it selects dropping burst. This paper evaluates the performance of RC-based DP model and general DP model using ns-2. The metrics of performance evaluation are TCP throughput, maximum sequence number of received TCP packets and drop rate of packet as simulation time increases.

• Neonatal Medicine
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• v.25 no.1
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• pp.16-22
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• 2018

Purpose: This study investigated predictive factors for severe neonatal thrombocytopenia, which greatly increases the need for intensive care and is associated with a high mortality rate in premature infants. Factors adopted for prompt identification of at-risk newborns include blood test results and birth history. This study analyzed the relationship between the presence of severe neonatal thrombocytopenia and the mortality rate. The causes of thrombocytopenia in premature infants were also examined. Methods: This retrospective study evaluated 625 premature infants admitted to the neonatal intensive care unit (NICU) at Chung-Ang University Medical Center. The neonates were classified into 3 groups according to the severity of thrombocytopenia: mild ($100{\times}10^9/L{\leq}platelet<150{\times}10^9/L$), moderate ($50{\times}10^9/L{\leq}platelet<100{\times}10^9/L$), or severe (platelet<$50{\times}10^9/L$). Analysis of blood samples obtained at the onset of thrombocytopenia included platelet count, white blood cell (WBC) count, hemoglobin level, hematocrit level, absolute neutrophil count, and high-sensitivity C-reactive protein level. Results: Of the 625 premature infants admitted to our NICU, 214 were detected with thrombocytopenia. The mortality rate in thrombocytopenic neonates was 18.2% (39/214), whereas a mortality rate of only 1.0% was observed in non-thrombocytopenic neonates. The major causes of thrombocytopenia were perinatal insufficiency and sepsis in premature infants. Severe thrombocytopenia was noted more frequently in premature infants with higher WBC counts and in those with a younger gestational age. Conclusion: Platelet count, WBC count, and gestational age are reliable predictors for severe neonatal thrombocytopenia. The major causes of thrombocytopenia were perinatal insufficiency and sepsis in premature infants.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.5
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• pp.422-430
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• 2010

Purpose: The aim of this study is that we evaluate the change of the White Blood Cell(WBC) count, Absolute Neutrophil Count (ANC), Erythrocyte Sedimentation Rate (ESR) and C-reactive Protein (CRP) values, and try to make standardization for postoperative sequels before and after the oral cancer resection and reconstructive surgery. Materials and Methods: The study was comprised of 34 patients (male 15, female 19) who were diagnosed as an oral cancer and had performed ablation and reconstructive surgery at Dankook university dental hos-pital. Each blood specimen was collected from patients and estimated WBC count, Neutrophil count, ESR, CRP on first, third, fifth, seventh day efore and after surgery and analyzing inter relationship between each value. Classifying Group I (resection with reconstructive surgery patients) and Group II (resection without reconstructive surgery patients). Also classifying group A (below 4 hours of operation time), Group B (4 to 8 hours of operation time), Group C (above 8 hours of operation time), each group was analyzed and compared. The Following results were induced. Results: (1) In coefficient of correlation, the CRP and WBC has highest value except WBC count and Neutrophil count. (2) There was no significant difference any lapse in the progress between Group I and II of WBC count, Neutrophil count, but the CRP shows statistically higher level in group I than group II at immediate postoperative day, and 1 to 5 days after surgery. (3) There is no significant difference any lapse in the progress between Group A, B, C of WBC count, Neutrophil count, but CRP shows statistically significant difference in 1 day, 3 days after surgery Conclusion: It should be suggested that, determination of CRP is most valuable parameter for postopera-tive management and determination of postoperative clinical changes than other parameter such as WBC count, neutrophil count, and ESR values in oral cancer patient after resection and reconstructive surgery, based on the results of this study.

• Korean Journal of Clinical Oncology
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• v.14 no.2
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• pp.120-127
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• 2018

Purpose: The purpose of this study was to determine the immunologic role of lymph node (LN) and stage migration by assessing LN count and metastatic LN count. Methods: A total of 2,117 patients with gastric adenocarcinoma located in the body and antrum who underwent distal/subtotal gastrectomy with D2 LN dissection between January 1, 1998 and December 31, 2008 were enrolled. LN count and number of metastases were determined in the N1 tier (area of D1 dissection) and N2 tier (area of D2 dissection). The lower and upper quartiles of LN counts in the same pN stage were grouped to compare the prognosis and LN positivity according to the LN tier. Results: Stage migration from N1 tier to N2 tier occurred in 3.2% of cases. The 5-year disease-specific survival rates of the upper and lower LN count groups within the N1 tier were 91.0% and 86.7% (P=0.01), respectively. LN positivity in the N2 tier of the lower LN count group was higher than that of the upper LN count group (14.1% vs. 8.2%, P<0.01). Stage migration in the N2 tier of the lower LN count group was also higher than that of the upper LN count group (4.6% vs. 1.8%, P<0.01). Conclusion: The lower LN count group had a decreased survival rate compared to that of the upper LN count group, suggesting that perigastric LN has an immunological defense role in weakening the disseminating power of metastatic tumor cells, as indicated by the LN count.