• Journal of Communications and Networks
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• v.7 no.3
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• pp.313-324
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• 2005

The success of the IEEE 802.11 standard has prompted research into efficiency of the different medium access methods and their support for different traffic types. A modified version of the point coordination function (PCF) called modified PCF has been introduced as a way to improve the efficiency over the standard method. It has been shown through a simulation study and a mathematical analysis that channel utilization can be much improved compared to the standard, in case there is no so-called hidden station problem. However, under the hidden station problem, the efficiency of the modified PCF would obviously decrease. In this paper, some enhancements of the modified PCF are introduced. Firstly, we propose a retransmission process to allow frames involved in collisions to be retransmitted. Then, we propose a collision resolution mechanism to reduce the frame collision probability due to the hidden station problem. In addition, we propose a priority scheme to support prioritization for different traffic types such as interactive voice and video, and real-time data traffic in the modified PCF. To prevent the starvation of one low priority traffic, minimum transmission period is also guaranteed to each traffic type via an admission control algorithm. We study the performance of the modified PCF under the hidden station problem and the performance of the modified PCF with priority scheme through simulations. To illustrate the efficiency of the priority scheme, we therefore compare its simulation results with those of some standardized protocols: The distributed coordination function (DCF), the enhanced distributed channel access (EDCA), the PCF, and our previously proposed protocol: The modified PCF without priority scheme. The simulation results show that the increment of delay in the network due to the hidden station problem can be reduced using the proposed collision resolution mechanism. In addition, in a given scenario the modified PCF with priority scheme can provide better quality of service (QoS) support to different traffic types and also support a higher number of data stations than the previous proposals.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.3
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• pp.950-975
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• 2016

Device-to-Device (D2D) communication underlaying cellular networks is a promising add-on component for future radio communication systems. It provides more access opportunities for local device pairs and enhances system throughput (ST), especially when mobile relays (MR) are further enabled to facilitate D2D links when the channel condition of their desired links is unfavorable. However, mutual interference is inevitable due to spectral reuse, and moreover, selecting a suitable transmission mode to benefit the correlated resource allocation (RA) is another difficult problem. We aim to optimize ST of the hybrid system via joint consideration of mode selection (MS) and RA, which includes admission control (AC), power control (PC), channel assignment (CA) and relay selection (RS). However, the original problem is generally NP-hard; therefore, we decompose it into two parts where a hierarchical structure exists: (i) PC is mode-dependent, but its optimality can be perfectly addressed for any given mode with additional AC design to achieve individual quality-of-service requirements. (ii) Based on that optimality, the joint design of MS, CA and RS can be viewed from the graph perspective and transferred into the maximum weighted independent set problem, which is then approximated by our greedy algorithm in polynomial-time. Thanks to the numerical results, we elucidate the efficacy of our mechanism and observe a resulting gain in MR-aided D2D communication.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.18 no.1
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• pp.72-79
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• 2008

This study was surveyed to assess the status of safety accidents occurred in work-places and prepare the fundamental data and prevent the safety accidents. The authors reviewed and analysed the charts of accident cases treated at a primary care clinic in A city from January 1991 to December 2006. The data were classified according to the USA Standards Institute and International Labour Organization method. We analyzed the data using SPSS program. The results were as follows : 1. The total cases of accidents were 455 for 8 years. 2. Accidents were mostly common in the workers who are in thirties and forties age(84.4%). 3. As season variation, spring and summer were common than others, but there was no statistical significance on season, month and weekday. 4. The most frequent injured part of the body were hand and finger, which was 36.0% among total cases. 5. According to the accidents type, cases of caught in, under or between were most frequently observed as 53.9% of the total cases. 6. The most common source of injuries was power machine(50.5%). 7. According to the unsafe acts, cases of carelessness and unsafe information were most frequently observed as 71.2% of the total cases. 8. Admission rate(5.5%) and official report rate(2.2%) were very low rate. As above results, the authors recommend to prepare the systemic control programs on environmental and human factors of safety accidents such as improving the working conditions, working facilities, working methods and safety education, and control of working time for working day.

• Journal of Trauma and Injury
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• v.30 no.4
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• pp.238-241
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• 2017

A 52-year-old man experienced blunt trauma upon falling from a height of 40 m while trying to repair the elevator. The patient's systolic blood pressure and hemoglobin levels were 60 mmHg and 7.0 g/dL, respectively, upon admission. A large volume of bloody discharge was observed in the open wound of the perianal area and sacrum. A computed tomography scan revealed an open comminuted sacral fracture with multiple contrast blushes. He underwent emergency laparotomy. Both internal iliac artery ligations were performed to control bleeding from the pelvis. Protective sigmoid loop colostomy was performed because of massive injury to the anal sphincters and pelvis. Pad packing was performed for a sacral open wound and perineal wound at the prone position. After resuscitation of massive transfusion, he underwent the second operation 2 days after the first operation. The pad was removed and the perineal and sacral open wounds were closed. After the damage-control surgery, he recovered safely. In this case, the hemodynamically unstable, open comminuted sacral fracture was treated safely by internal iliac artery ligation with pad packing.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.5
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• pp.2777-2782
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• 2013

The aim of the present study was to assess criterion validity and external reliability of a questionnaire on risk factors for breast cancer. Materials and Methods. Women with breast cancer diagnosis (the cases) (N=40) and matched individuals without cancer (the controls) (N=40) were asked to fill in a questionnaire twice: on a day of admission to hospital (Q1) and on a day before discharge (Q2), with a time interval of 4-6 days. The questionnaire included questions (N=150) on demographic and socioeconomic factors, diseases in the past, family history of cancer, woman's health, smoking, alcohol use, diet, physical activity, and work environment. Criterion validity of the questionnaire Q2 relative to reference questionnaire Q1 was assessed with the Spearman correlation coefficient (SCC); external reliability of the questionnaire was measured in terms of the intraclass correlation coefficient (ICC). Statistical analysis was performed with SPSS 16. Results. The responses to most of the questions on socioeconomic factors, family history on cancer, female health, lifestyle risk factors (smoking, alcohol use, physical activity) correlated substantially in both the cases and the controls with SCC and ICC>0.7 (p<0.01). Statistically non significant relationships defined only between the responses on amount of beer the cases drank at the ages up to 25 years and 26-35 years as well as time of use of estrogen and estrogens-progestin during menopause by the cases. Moderate and substantial SCC and ICC were determined for different food items. Only the response of the cases on veal consumption did not correlate significantly. Conclusions. The questionnaire on breast cancer risk factors is valid and reliable for most of the questions included.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.7
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• pp.3259-3263
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• 2016

Aims: To determine suitable food textures for videofluoroscopic study of swallowing (VFSS), in order to predict and prevent subsequent aspiration pneumonia in esophageal cancer patients with dysphagia after surgery. Materials and Methods: We evaluated 45 hospitalized esophageal cancer patients who underwent surgery between January 2012 and December 2013. The control group consisted of 43 patients treatmed from January 2010 until December 2011 and were not examined by VFSS. Test foods, which were presented in order of increasing thickness, included thin barium sulfate (Ba) liquid (3 or 10 ml), slightly thickened Ba liquid (3 or 10 ml), a spoonful of Ba jelly, and a spoonful of Ba puree. Results: Patients could most safely swallow puree, followed by jelly. The 3-mL samples of both the thin and thick liquids put patients at risk for aspiration pneumonia, with incidence rates of 13% and 11%, respectively. While 64.4% of patients could swallow all test foods and liquids safely, 35.6% were at risk for aspiration pneumonia when swallowing liquids. Even though >30% of patients were at risk, only 1 (2.2%) in the VFSS group developed aspiration pneumonia, which occurred at the time of admission. Following VFSS, no incidence of aspiration pneumonia was observed. However, aspiration pneumonia occurred in 4 (9.3%) control patients during hospitalization. Conclusions: Postoperative esophageal cancer patients were more likely to aspirate any kind of liquid than solid foods, such as jellies. VFSS is very useful in determining suitable food textures for postoperative esophageal cancer patients.

• Child Health Nursing Research
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• v.7 no.1
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• pp.108-117
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• 2001

This research objected to the diagnosed patients as acute lymphoblastic leukemia, acute myelogenous leukemia, neuroblastoma, non-Hodgkins lymphoma, Hodgkin's disease, kidney tumor, myelodysplastic syndrom and juvenile chronic leukemia after admission in the 'P' hospital in Pusan from Aug. 1. 1999 to Jan. 31. 2000. The results of this study are summarized as follows. 1. On the specific character between the experimental(exp.) group and the control (con.) group : there were 7 of 4-7 years old patients(the most) in the experimental group(53.8％), 5 of 12 years old or older patients in the control group (38.5％). Patients who experienced operation were 7 in the exp. group(53.8％) and 6 in con. group(46.2％). The largest number of the patients' diagnosis was acute lymphoblastic leukemia by 5 in the exp. group(38.5％) and 4 in the con. group (30.8％). The hardest nausea came on the second day by 5 in the exp. group(38.5％), 9 in the con. group(69.2％). 2. P-score of the nausea vomiting on the number of daily anticancer drug administration : first day, the exp. group got 9.6 and the con. group 17.6(P = 0.03). 2nd day, 10.9 and 19.4(P = 0.00), 3rd day, 10.6 and 18.3(P = 0.00), 4th day 10.0 and 18.0, 5th day 10.9 and 16.8(P = 0.05). The score showed statistically significant difference(P < .05). 3. Oral intake didn't show statistically significant difference between two groups. However the average of Oral intake of the exp. group was continually higher than the con. group except to the first day after administration. In conclusion, nursing intervention and nutrition care are much more needed on the 2-3th day after administration to reduce nausea vomiting, and for remission of nausea and enlarging oral intake it is utilizable to apply the easy, economic Oral Cryotherapy to the young patients who undergo chemotherapy.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.51-55
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• 2008

Request High-Images, High-quality, duplex transmission, BcN Voice telephone, Broadcast, Data internet service came to be all possible and demolished original communication service area. Also, The quality is guaranteed stablely to new business and ISP the requirement comes to become a multicasting quality guarantee mechanism which there is the reliability for a information communication and High-quality multimedia service. Like this, a multicast mechanism to be guaranteed must become air control End-to-End QoS for a service supply, a transmission delay a packet loss or requirement which the user requests guarantee and multicast Path-NET which there is the reliability must be provided. Therefor, we proposed IP base multicast new join the present the multicast mechanism of Probing packet foundation which there is the efficiently a linking acceptance, we used ns-2 simulator for the performance evaluation of the proposed.

• Korean Journal of Clinical Pharmacy
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• v.31 no.2
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• pp.136-144
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• 2021

Background: Zinc is known for modulating antiviral and antibacterial immunity and regulating inflammatory response. This study aimed to examine the effect of zinc supplementation on clinical outcomes of hospitalized COVID-19 patients through systematic literature review and meta-analysis. Methods: PubMed/Medline, Embase, and Cochrane library databases were searched for studies comparing zinc supplement group versus control group for clinical outcomes of COVID-19 up to November 3, 2020. The search results were updated on February 9, 2021. The meta-analysis was performed by RevMan 5.4 software. Results: Total 4 studies were included in this systematic review. The zinc administered group had a significantly lower mortality rate compared with the control group (odds ratio [OR] 0.63, 95% confidence interval [95% CI] 0.53-0.75, p<0.001), with significantly higher discharge rate (OR 1.32, 95% Cl 1.15-1.52, p<0.001). However, there were no significant differences in the intensive care unit admission rate (OR 1.07, 95% Cl 0.26-4.48, p=0.92), mechanical ventilation rate (OR 0.80, 95% Cl 0.45-1.41, p=0.44), and length of hospital stay (mean difference 0.75, 95% Cl -0.64 to 2.13, p=0.29) between the two groups. Conclusion: The meta-analysis of zinc administration showed positive clinical effects on the discharge rate and mortality of COVID-19 hospitalized patients. However, large-scale randomized controlled trial should be conducted for zinc to be considered as one of the adjuvant treatments.

• Tuberculosis and Respiratory Diseases
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• v.85 no.1
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• pp.47-55
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• 2022

Background: We evaluated the long-term effects of domiciliary noninvasive positive-pressure ventilation (NIPPV) used to treat patients with chronic obstructive pulmonary disease (COPD). Methods: Databases were searched to identify randomized controlled trials of COPD with NIPPV for longer than 1 year. Mortality rates were the primary outcome in this meta-analysis. The eight trials included in this study comprised data from 913 patients. Results: The mortality rates for the NIPPV and control groups were 29% (118/414) and 36% (151/419), suggesting a statistically significant difference (risk ratio [RR], 0.79; 95% confidence interval [CI], 0.65-0.95). Mortality rates were reduced with NIPPV in four trials that included stable COPD patients. There was no difference in admission, acute exacerbation and quality of life between the NIPPV and control groups. There was no significant difference in withdrawal rates between the two groups (RR, 0.99; 95% CI, 0.72-1.36; p=0.94). Conclusion: Maintaining long-term nocturnal NIPPV for more than 1 year, especially in patients with stable COPD, decreased the mortality rate, without increasing the withdrawal rate compared with long-term oxygen treatment.