• The Korean Journal of Emergency Medical Services
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• v.10 no.1
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• pp.51-60
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• 2006

Background: The toxicity of paraquat has been known to be caused by oxygen free radicals which leads to the lipid peroxidation and multiple organ failure. High dose vitamin C has been known to be a effective antioxidant activities against the paraquat intoxication. This study was designed to evaluate the effect of regular injection of high dose vitamin C on liver damage in paraquat poisoned rat model. Method: Fifty five rats of Sprague-Dawley strain were divided into three groups: control group, only intraperitoneally injected saline; paraquat group, single dose intraperitoneally injected paraquat(24.5%, 40 mg/kg) and every 8 hours injected saline; paraquat and vitamin C group, single dose intraperitoneally injected paraquat(24.5%, 40 mg/kg) and every 8 hours injected vitamin C(72 mg/kg). Rats were sacrificed on the 12 hours, 1st day, 2nd day, 4th day, 7th day after injection and liver tissue was obtained. H&E(Hematoxylin & Eosin) stain and Masson's trichrome stain for collagen fiber detection were undertaken. The results were observed using the microscope. Results: 1. There were no differences between control and experimental group at the 12hours after regular injection of high dose vitamin C. 2. There were significantly decreased liver damage in experimental group in the 1st day after regular injection of high dose vitamin C. 3. There were significantly increased recovery of liver damage with time in experimental group after regular injection of high dose vitamin C. Conclusion: These results suggest that regular injection of high dose vitamin C is effective in decreasing liver damage in paraquat intoxication.

• Journal of Advanced Navigation Technology
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• v.20 no.4
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• pp.352-360
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• 2016

In this paper, a novel multiple multicast feed-back scheme for improving multimedia multicast and broadcast system based on IEEE 802.11. The proposed scheme improves multicast PPDU delivery ratio of next generation wireless LAN by utilizing multicast feed-back information. By using the proposed scheme, regardless of its size of multicast group, an AP STA could collect transmission failure information by receiving simultaneous NAK frame. The proposed scheme shows large performance enhancement in broadcast or multicast system of Intelligent Transport System and Passenger Entertainment Service. According to the analysis results, the proposed scheme could enhance wireless LAN multicast and broadcast performance significantly.

• Journal of KIISE:Information Networking
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• v.31 no.6
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• pp.573-581
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• 2004

Recently, the rapid growth of Internet technology and the deployment of high speed networks make many kinds of multimedia services possible. Preexisting multimedia services are designed based on the client/server model which has the problems such as the network failure and the low speed communication due to the high load on the central server. In order to solve these problems, peer-to-peer networks are introduced and expanded through Internet environments. In this paper, we propose a pure peer-to-peer network based resource discovery mechanism for multimedia services. In the proposed scheme, each host maintains the location information of resources which are recently requested by other hosts as well as that oi the replicas of local resources. The proposed scheme has the faster response time and incurs the smaller traffic than the preexisting discovery schemes in pure peer-to-peer network environments. Also, by decentralizing the location information and differentiating the reply path, our proposed scheme can solve the search result loss problem that occurs when the network is unsettled.

• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.2
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• pp.197-203
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• 2001

Micro-defects induced by design and production failure or working environments are known as the cause of SCC(Stress Corrosion Cracking) in aged structures. Therefore, the evaluation of structural integrity based on micro-cracks is required not only a manufacturing step but also in-service term. So we introduce a new nondestructive inspection method using the magneto-optical film to detect micro-cracks. The method has some advantage such as high testing speed, real time data acquistion and the possibility of remote sensing by using of a magneto-optical film that takes advantage of the change of magnetic domains and domain walls. This paper introduces the concept of the new nondestructive inspection method using the magneto-optical film, also proves the possibility of this method as a remote testing system under oscillating load considering application on real fields by applying the method to four types of specimens.

• International Journal of Aeronautical and Space Sciences
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• v.1 no.1
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• pp.48-61
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• 2000

Korea Aerospace Research Institute (KARI) have gained experience with Helicopter Vibration Health Monitoring (VHM) System technology with the help of UK GKN-WHL. GKN-WHL have had many years of experience with the research and development of vibration analysis techniques to improve the health monitoring of helicopter transmissions. This activity was targeted at transmission rig testing at first, but the techniques have been progressively developed where they are now used as a part of integrated Health and Usage Monitoring (HUM) systems on many types of in-service and new helicopters. The technique development process has been considerably aided by an ever expanding database of transmission monitoring experience from both the rig testing and aircraft operations. This experience covers a wide range of failure types from naturally occurring faults to crack propagation studies and covering a wide range of transmission configurations. Primarily based on accelerometer signals GKN-WHL's vibration analysis methods have also been applied to a variety of other sensor types. The transition from an experimental environment to operational VHM systems has been a lengthy process, there being a need to demonstrate technique reliability as well as effectiveness to both regulatory (Airworthiness Authority) and commercial organizations. Another important feature of this process has been the development of close relationships with a number of VHM system hardware and software suppliers. Such an experienced GKN-WHL provides various raw vibration data which was acquired from transmission ground test rig and allow KARI to develop it's own analysis program. KARI made a program and then analyzed the data to coma pre with the results of GKN-WHL. The KARI's results both time domain signals and statistical values show comparable to GKN's.

• Journal of the Korean Society for information Management
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• v.24 no.3
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• pp.21-41
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• 2007

IT outsourcing has become a critical component of organizations, but improper expectations, ambiguous contracts and unclear goals frequently cause the failure of IT outsourcing. Especially we have to be concerned about the uncareful management of customer-supplier relationships based on a psychological contract perspective. This study focuses on the obligations of contractual parties for IT outsourcing which influence the outsourcing relationship(OR) and the successful performance of IT outsourcing(OP). The supplier obligations consist of the achievable infrastructure(S1) and capability(S2), and the customer obligations is composed of the acceptable environment(C1) and acceptability(C2) for IT outsourcing. This paper shows that the S1, S2, and C2 have an effect on the OR, the OR on the OP, and the S2 also on the OP directly. The four components of customer-supplier obligations are mutually related to each other. What is more, we must notice that the S2 has strong connections with the C2.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.5
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• pp.424-434
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• 2017

In industrial wireless sensor networks, many applications require integrated QoS supporting. This paper proposes a reliable protocol for real-time monitoring in industrial wireless sensor networks. Retransmission is well-known to recover the transmission failure, however, this might cause the time delay to violate the real-time requirement. The proposed protocol exploits broadcasting feature of wireless networks and the temporal opportunity concept. The opportunities to relay the data packets are shared by the broadcasting feature and the temporal opportunity concept maximize the number of candidates in communication. Simulation results show that the proposed protocol is superior to the existing real-time protocols in term of real-time service and reliability.

• Health Policy and Management
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• v.30 no.3
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• pp.335-344
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• 2020

Background: The purpose of this study was to identify factors inhibiting access of people with disability to health check-ups as well as identify pertinent solutions for improvement. Methods: Twenty-three people with disability older than the age of 19 who took respective health check-ups within the last 3 years were selected as participants. For the data collection, the 1:1 intensive interview was used. The data were analyzed by the grounded theory by Corbin and Strauss. Results: The results comprised nine categories, 23 subcategories, and 179 concepts. The central phenomenon was 'failure to obtain check-ups.' Causal conditions were observed as a 'lack of communication method,' 'physical difficulties,' and 'staff unfamiliar with people with disability,' Interventional conditions comprised 'physical accessibility,' 'staffs' competency,' and 'assistant manpower.' The active strategy was included 'to investigate the professional medical institution,' 'to find the medical institution of convenient traffic accessibility,' 'to overcome communication difficulties through equipment,' and 'to overcome linguistic barriers through sufficient communication.' Whereas, 'utilization of ancillary equipment,' 'the education of staffs on people with disability,' 'universal design manual,' and 'customized check-ups' were included in the passive strategy. Such processes arose in the contextual conditions of 'lack of expectations for daily lives' and 'lack of government support.' As a consequence, the subjects participated experienced the 'disadvantages,' 'discrimination,' and 'reduced reliability of the health check-ups.' Conclusion: The subjects who participated in this study emphasized 'staffs familiar with people with disability' and 'systems customized for people with disability' are mandatory to secure complete health check-ups for people with disability.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.9
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• pp.26-31
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• 2003

Aging aircraft accumulates widespread fatigue damage commonly referred to as multiple site damage(MSO). For ductile material such as 2024-T3 aluminum, MSO may lower the service life below that which is predicted by conventional fracture mechanics. The present paper is concerned with the fatigue life extension by pre-indentation technique for thin 2024-T3 aluminum plate to decelerate the crack propagation rate in the panels with MSO. The panel with fastener holes can be simply modelled by Hole/Slot type Middle-Tension specimen. Results of fatigue testing show significantly improving failure cycles from 10 to 40 times. This retardation effect is decreased by increasing the loading level in the constant amplitude loading. In the sense of retardation mechanism, the crack propagation rate is gradually attenuated by entering the indentation mark and maintains at the lowest value for a long period after the edge of crack passes the center of indentation area.

• Quality Improvement in Health Care
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• v.10 no.2
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• pp.216-231
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• 2003

Objectives: To develop a model that predicts a death probability of acute myocardial infarction(AMI) patient, and to evaluate a performance of hospital services using the developed model. Methods: Medical records of 861 AMI patients in 7 general hospitals during 1996 and 1997 were reviewed by two trained nurses. Variables studied were risk factors which were measured in terms of severity measures. A risk model was developed by using the logistic regression, and its performance was evaluated using cross-validation and bootstrap techniques. The statistical prediction capability of the model was assessed by using c-statistic, $R^2$ as well as Hosmer-Lemeshow statistic. The model performance was also evaluated using severity-adjusted mortalities of hospitals. Results: Variables included in the model building are age, sex, ejection fraction, systolic BP, congestive heart failure at admission, cardiac arrest, EKG ischemia, arrhythmia, left anterior descending artery occlusion, verbal response within 48 hours after admission, acute neurological change within 48 hours after admission, and 3 interaction terms. The c statistics and $R^2$ were 0.887 and 0.2676. The Hosmer-Lemeshow statistic was 6.3355 (p-value=0.6067). Among 7 hospitals evaluated by the model, two hospitals showed significantly higher mortality rates, while other two hospitals had significantly lower mortality rates, than the average mortality rate of all hospitals. The remaining hospitals did not show any significant difference. Conclusion: The comparison of the qualities of hospital service using risk-adjusted mortality rates indicated significant difference among them. We therefore conclude that risk-adjusted mortality rate of AMI patients can be used as an indicator for evaluating hospital performance in Korea.