• Journal of Digital Contents Society
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• v.14 no.3
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• pp.283-290
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• 2013

The current centralized mobility control protocols such as proxy mobile IPv6 (PMIPv6) are dependent on a central mobility anchor to process all control/data traffic. However, such centralized mobility control protocols have some drawbacks such as traffic concentration into the core network and serious service degradation in case of the failure of such a centralized mobility anchor, etc. In this paper, therefore, in order to alleviate these drawbacks, we propose a PMIPv6-based distributed mobility control scheme considering a user's movement locality. Performance evaluation results demonstrate that the proposed scheme has apparent potentials to alleviate serious drawbacks of S-PMIP, which is a closely-related distributed mobility control scheme, as well as PMIPv6, while reducing the total mobility control cost.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.5
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• pp.349-357
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• 2022

Since the flight control computer of unmanned aerial vehicle (UAV) is a flight critical equipment, it is necessary to ensure reliability and safety from the development step, and a redundancy-based fault management design is required in order to operate normally even a failure occurs. To reduce cost, weight and power consumption, the dual-redundant flight control system design is considered in UAV. However, there are various restrictions on the fault management design. In this paper, we propose the fault detection and isolation designs for the dual-redundant flight control computer to satisfy the safety requirements of an UAV. In addition, the flight control computer developed by applying the fault management design performed functional tests in the integrated test environment, and after performing FMET in the HILS, its reliability was verified through flight tests.

• KIPS Transactions on Computer and Communication Systems
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• v.6 no.6
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• pp.261-270
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• 2017

With the development of smart on-devices and communication technology, demand for non-stop services is increasing. Therefore, the high availability for continuously providing services in the event of system failure has been spotlighted. Meanwhile, because most internet-based services are provided by using TCP, an efficient TCP session recovery technique for providing non-stop services is required. However, the existing TCP session recovery techniques are inefficient because it has a high recovery cost or does not support failover operation, To solve these problems, in this paper, we propose a TCP session recovery technique for high availability in smart on-devices. For this, we first recover the TCP session without re-establish the TCP session by correcting a sequence number and a acknowledgment number. Second, we synchronize the TCP session recovery data between the master and the server, and then we operate the failover operation when master server fails. Finally, we provide the non-stop service to peer by using the virtual IP number and the transmission of GARP (Gratuitous ARP) packet.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.1 no.1
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• pp.37-44
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• 1998

Purpose: This study aimed at evaluating the therapeutic outcome, cost effectiveness and recurrence rate in children with H. pylori infection after the treatment using various medications. Methods: Seventy five children (mean age $11.4{\pm}2.5$ years) were given an endoscopy with biopsy and H. pylori status assessed by CLO test and histologic examination (Warthin Starry stain). Children were given one of following medications such as DA ($Denol^{(R)}$ and amoxycillin), OA (omeprazole and amoxycillin), DC ($Denol^{(R)}$ and clarithromycin) as primary treatment. And one of following medications such as DAM ($Denol^{(R)}$, amoxycillin and metronidazole), DC, OA, OC (omeprazole and clarithromycin) were used in children who failed the eradication of H. pylori. Results: The endoscopic diagnoses were: nodular gastritis (46 cases), gastric ulcer (9), duodenal ulcer (6), superficial gastritis (6), and normal (8). H. pylori eradication rate was 91% (63 of 69 children) on 4 weeks course of DA, 50% (1 of 2 cases who had treatment failure on DA) on DAM, and 75% (3 of 4 cases who treated on DC primarily) and 50% (1 of 2 cases who had treatment failure on DA) on DC, and 100% on OA (all of 2) and on OC (all of 1 who failed on DA). In 3 of 7 children in whom H. pylori had not been eradicated by primary medications (DA 6 and DC 1 case), H. pylori was re-eradicated by secondary medications (DA 1, DAM 1 and DC 1 case). But in remaining 4 cases, H. pylori infection persisted. Reinfection of H. pylori was found in 4 of 75 children between 3 months and 3 years after completion of the treatment of DA, yielding recurrence rate of 5.3%. In 2 of 4 cases who had relapsed, H. pylori was re-eradicated by secondary medications (OC 1 and DA 1 case). But in remaining 2 cases, H. pylori infection persisted. Conclusion: These results suggest that dual therapy with $Denol^{(R)}$ and amoxycillin is the effective medications in treating H. pylori infection in children. Concerning the cost effectiveness, it can be recommended as first line treatment of choice as well.

• Journal of Korean Academy of Nursing
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• v.22 no.4
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• pp.491-505
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• 1992

The purpose of this research was to understand the structure of the lived experience of parents of a child terminally ill with cancer The research question was “What is the structure of the experience of parents of a child terminally ill with cancer\ulcorner” The sample consisted of 17 parents of children admitted to the cancer units of two university hospitals in Seoul. The unstructured interviews were carried out from October 10, 1991 through January 10, 1992. They were audio-recorded and analysed using Van Kaam's method. Parents ascribed the cause of the cancer to the mother's emotional imbalance during pregnancy, the mother's stress, failure to observe religious rites, food, the parent's sin, misfortune and pollution. The theme clusters were tension, fear and depression experienced during pregnancy, stress that children suffer from abusive parents, failure to observe religious activites, bad luck, and sins committed during a previous life. When the child suffered a recurrence of cancer, the parents experienced negative emotions, nervousness, sorrow. depression and death. The theme clusters were feelings of despair, helplessness, regret, guilt, insecurity, emptyness and apathy. The long struggle with cancer resulted in the loss of economic security, loss of psychological and physical well being, and social withdrawal. The theme clusters were the economic burden of medical cost, giving up treatment, debt, limited medical insurance coverage and blood transfusion. The loss of psychological well being included stress, lack of support systems, inability to carry out responsibilities, lack of trust of the medical ten family breakdown, inappropriate expression of emotion and not disclosing the diagnosis to the child. Physically the parents suffered fatigue, insomnia, loss of appetite, loss of weight, dizzness, headache, psychosomatic symptoms, and increased consumption of liquor and cigarettes. Social withdrawal was manifested by taking time off from work to look after the child, decrease of outside social activities and feelings of isolation. Influences on family life were spousal conflicts, negative response of siblings, separation of the family members and economic hardship. The theme clusters were blaming a spouse for the cause of the illness and disagreements, maladjustment, lonliness, hostility and depression of siblings. The high price of medical care over the long period was a major factor influencing the life of the family. Positive experiences during the child's long illness were the strengthening of support systems and religious beliefs and financial help from social organizations. The support of one's spouse primarily helped to overcome the stress of the long illness. In addition, support was received from parents of other children with cancer and from nurses and religious leaders. The nurse, by providing empathetic support, should be a person with whom parents can express their feelings and share their experiences.

• Journal of the Korean Society for Nondestructive Testing
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• v.14 no.2
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• pp.122-131
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• 1994

Journal bearings in the rotating machineries are vulnerable to the contamination or the insufficient supply of lubricating oil, which is likely to be the cause of unexpected shutdown or malfunction of these systems. Various destructive and nondestructive testing methods had been used for the reduction of maintenance cost and the operational safety problems due to the accidents related to bearing damages. In this experimental approach, acoustic emission monitoring is employed to the detection of incipient failure caused by intervention of foreign particles most probable in the journal bearing systems. Experimental schedules for the intervention of foreign particles was composed to be more quantitative and systematic than last study in consideration of minimum oil film thickness and particle size. The experiment was conducted under such designed conditions as inserting alumina particles to the lubrication layer in the simulated journal bearing system. Several parameters such as AE rms level, waveform, AE energy distribution and other AE event parameters are used for analysis and characterization of damage source. The results showed that the history of damage was well correlated with the changes of AE rms level and the type of damage source signal can be verified using other informations such as waveform, distributions of AE parameters etc.

• Korea Journal of Hospital Management
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• v.23 no.1
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• pp.87-106
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• 2018

Objective: The objective of this study is to examine the association between process quality of inpatient care and risk-adjusted, thirty-day potentially preventable hospital readmission (PPR) rates. Data Sources/Study Setting: This was an observational cross-sectional study of nonfederal acute-care hospitals located in two states California and Florida, discharging Medicare patients with a principal discharge diagnosis of heart failure, acute myocardial infarction, or pneumonia January through December 31, 2007. Data were obtained from the Healthcare Cost and Utilization Project State Inpatient Database of the Agency for Healthcare Research and Quality, Centers for Medicare and Medicaid Services Hospital Compare database, and the American Hospital Association Annual Survey of Hospitals. Study Design: The dependent variable of this study is condition-specific, risk-adjusted, thirty-day potentially preventable hospital readmission (PPR). 3M's PPR software was utilized to determine whether a readmission was potentially preventable. The independent variable of this study is hospital performance for process quality of inpatient care, measured by hospital adherence to recommended processes of care. We used multivariate hierarchical logistic models, clustered by hospitals, to examine the relationship between condition-specific, risk-adjusted, thirty-day PPR rates and process quality of inpatient care, after taking clinical and socio-demographic characteristics of patients and structural and operational characteristics of hospitals into account. Findings: Better performance on the process quality metrics was associated with better patient outcome (i.e., low thirty-day PPR rates) in pneumonia, but not generally in two cardiovascular conditions (i.e., heart failure and acute myocardial infarction). Practical Implication: Adherence to the process quality metrics currently in use by CMS is associated with risk-adjusted, thirty-day PPR rates for patients with pneumonia, but not with cardiovascular conditions. More evidence-based process quality metrics closely linked to 30-day PPR rates, particularly for cardiovascular conditions, need to be developed to serve as a guideline to reduce potentially preventable readmissions.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.10
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• pp.29-39
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• 2008

Greedy routing which is easy to apply to geographic wireless sensor networks is frequently used. Greedy routing works well in dense networks whereas in sparse networks it may fail. When greedy routing fails, it needs a recovery algorithm to get out of the communication void. However, additional recovery algorithm causes problems that increase both the amount of packet transmission and energy consumption. Communication void is a condition where all neighbor nodes are further away from the destination than the node currently holding a packet and it therefore cannot forward a packet using greedy forwarding. Therefore we propose a VODUA(Virtually Ordered Distance Upgrade Algorithm) as a novel idea to improve and solve the problem of void. In VODUA, nodes exchange routing graphs that indicate information of connection among the nodes and if there exist a stuck node that cannot forward packets, it is terminated using Distance Cost(DC). In this study, we indicate that packets reach successfully their destination while avoiding void through upgrading of DC. We designed the VODUA algorithm to find valid routes through faster delivery and less energy consumption without requirement for an additional recovery algorithm. Moreover, by using VODUA, a network can be adapted rapidly to node's failure or topological change. This is because the algorithm utilizes information of single hop instead of topological information of entire network. Simulation results show that VODUA can deliver packets from source node to destination with shorter time and less hops than other pre-existing algorithms like GPSR and DUA.

• The Journal of Bigdata
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• v.7 no.1
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• pp.125-137
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• 2022

The transportation industry is one of the important industries due to the geographical requirements surrounded by the sea on three sides of Korea and the problem of resource poverty, which relies on imports for most of its resource consumption. Among them, the proportion of the shipping industry is large enough to account for most of the transportation industry, and maintenance in the shipping industry is also important in improving the operational efficiency and reducing costs of ships. However, currently, inspections are conducted every certain period of time for maintenance of ships, resulting in time and cost, and the cause is not properly identified. Therefore, in this study, the proposed methodology, LSTM-AutoEncoder, is used to detect abnormalities that may cause ship failure by considering the time of actual ship operation data. In addition, clustering is performed through clustering, and the potential causes of ship main engine failure are identified by grouping outlier by factor. This enables faster monitoring of various information on the ship and identifies the degree of abnormality. In addition, the current ship's fault monitoring system will be equipped with a concrete alarm point setting and a fault diagnosis system, and it will be able to help find the maintenance time.

• Journal of the Institute of Convergence Signal Processing
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• v.16 no.2
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• pp.74-82
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• 2015

In this study, a BMW plant process control system model which produces BMW is suggested and the BMW plant process controller with the following functions is developed. The first function is to operate the electronic overload relays to stop the blower for a certain period of time and to re-operate it again when the blower is overloaded. The second function is to close the motor operated valve automatically in case of power failure to prevent the circulation from the guided tank to the compost throwing tank and to block leak from the compost throwing tank due to the failure of ball valve. The third function is to transfer produced BMW from the concentration tank to 4 storage tanks for automatic managing of the BMW output. A device to measure the signal of the BMW plant process controller and a test equipment are developed. The designed BMW plant process controller is checked to see if it operates correctly according to the design specifications. The sequence control method based on BMW plant process controller is developed at a low cost in this study, so it is expected to bring improvements in the stability and the efficiency of system and to cause reductions in the operation and the management costs in the future.