• The KIPS Transactions:PartD
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• v.10D no.6
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• pp.935-948
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• 2003

An online scaling method adds new nodes to the shared-nothing database cluster and makes tables be reorganized while the system is running. The objective is to share the workload with many nodes and increase the capacity of cluster systems. The existing online scaling method, however, has two problems. One is the degradation of response time and transactions throughput due to the additional overheads of data transfer and replica's condidtency. The other is and inefficient recovery mechanism in which the overall scaling transaction is aborted by a fault. These problems deteriorate the availability of shared-nothing database cluster. To avoid the additional overheads throughout the scaling period, our scalingmethod consists of twophases : a parallel data transfer phase and a combination phase. The parallel data transferred datausing reduces the size of data transfer by dividing the data into the number of replicas. The combination phase combines the transferred datausing resources of spare nodes. Also, our method reduces the possibility of failure throughout the scaling period and improves the availability of the database cluster.

• Journal of the Korea Society of Computer and Information
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• v.19 no.6
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• pp.109-117
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• 2014

A cold storage is a warehouse of a insulated building with cooling installations. It has many different types of cold rooms with temperatures below 0 degrees Celsius, and the sequential workflow such as receiving, picking and packing runs in that rooms. Recently, the cold storages have adopted RFID technology, and consequently, warehouse product management in them are becoming intelligent and network. However, information inconsistency in warehouses caused by physical and logical errors reduces reliability in the RFID cold storage management system and worsens their work efficiency. Therefore, it is necessary to develop an early detection system to identify errors. In this paper, we suggest a supervisory system detecting logical errors on business processes of the RFID cold storage. It is composed of a master supervisor and mobile supervisor. In the master supervisor, the manager can set the constraints conditions and get alerts, and in the mobile supervisor, the workers confirm and deal with these faults directly. The supervisory system improve reliability of the RFID cold storage management system by recognizing a failure to identify physically and logically using these constraint conditions. This paper shows that the supervisory system can reduce the average recovery time to improve reliability by decreasing the time for detecting and analyzing errors in the RFID cold storage management system.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.5
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• pp.919-929
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• 2014

Recently, organizational efforts to adopt ISMS(Information Security Management System) have been increasingly mandated and demanded due to the rising threat and the heavier cost of security failure. However there is a serious gap between awareness and investment of information security in a company, hence it is very important for the company to control effectively a variety of information security threats within a tight budget. To phase the ISMS, this study suggests the priorities based on evaluating the Importance of 13 areas for the ISMS by the information security experts and then we attempt to see the difference between importance and investment through the assessment of the actual investment in each area. The research findings show that intrusion incident handling is most important and IT disaster recovery is the area that is invested the most. Then, information security areas with the considerable difference between priorities of importance and investment are cryptography control, information security policies, education and training on information security and personnel security. The study results are expected to be used in making a decision for the effective investment of information security when companies with a limited budget are considering to introduce ISMS or operating it.

• Journal of Korean society of Dental Hygiene
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• v.6 no.4
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• pp.283-294
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• 2006

The purpose of this study was to examine the state of smoking among some college students, the smoking motivation of smoker students, what made them quit smoking and how they got ready for giving up smoking, as smoking had a huge impact on national health and there was a desperate necessity for preventive antismoking education programs to let students keep away from smoking. After a survey was conducted with self-administered questionnaires from October 1 through November 1, 2006, the responses from 400 students were gathered, and 384 answer sheets were analyzed except 16 incomplete ones. The findings of the study were as follows: 1. By gender, 62.4% of the male students and 28.6% of the female students were smokers, and the state of smoking was statistically significantly different according to their gender(p<0.05). 2. The largest number of the male students, which accounted 44.1%, started smoking in their high school days, and 39.5% of the females did that in middle school. As for a daily mean amount of smoking, 41.8% of the male students, the greatest percentage, smoked 10 to 19 cigarettes a day, and one to nine cigarettes were most common among the females, which represented 57.9 %. But the gap between the two was insignificant(p>0.05). As many as 83.6% of the males and 86.8% of the females had ever attempted to quit it. 3. Concerning awareness of antismoking policies, they felt that a raise in cigarette price would lead to less smoking, and that antismoking advertisement or posters through television or newspaper would deliver the same results as well. There was a statistically significant difference among their awareness(p<0.05). 4. Regarding preparation stage for quitting smoking, 31.3% of the male smokers had no intention to give it up, and 23.2% considered it. 36.7%, the largest percentage, got ready to refrain from it. Among the female smokers, 34.2% had no plans to abstain from smoking, and 36.8% took it into consideration. 23.7% got ready to do that. The females who got ready for that were outnumbered the males who did. 5. As to connections between the state of smoking and relevant knowledge, the students didn't have a good knowledge on that, and a statistically significant difference existed between the smokers and nonsmokers in smoking knowledge. 6. As for knowledge about oral diseases, they were highly cognizant of the relationship of smoking to tooth discoloration, nicotine stomatitis and bad breath, but they didn't know well about its relationship to delayed recovery from dental treatment, implant failure and ozena. Their smoking condition made a statistically significant difference to their knowledge(p<0.05). In the future, sustained research efforts should be channeled into determining how much smoking affects health and concerns oral diseases, and antismoking counseling programs should be prepared to bolster people's awareness of oral health.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.2
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• pp.295-310
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• 2014

DCS (Distributed Control System), the main control system of power plants, is an automated system for enhancing operational efficiency by monitoring, tuning and real-time operation. DCS is becoming more intelligent and open systems as Information technology are evolving. In addition, there are a large amount of investment to enable proactive facility management, maintenance and risk management through the predictive diagnostics. However, new upcoming weaponized malware, such as Stuxnet designed for disrupting industrial control system(ICS), become new threat to the main control system of the power plant. Even though these systems are not connected with any other outside network. The main control systems used in the power plant usually have been used for more than 10 years. Also, this system requires the extremely high availability (rapid recovery and low failure frequency). Therefore, installing updates including security patches is not easy. Even more, in some cases, installing security updates can break the warranty by the vendor's policy. If DCS is exposed a potential vulnerability, serious concerns are to be expected. In this paper, we conduct the penetration test by using NESSUS, a general-purpose vulnerability scanner under the simulated environment configured with the Ovation version 1.5. From this result, we suggest a log analysis method to detect the security infringement and react the incident effectively.

• Journal of Chest Surgery
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• v.45 no.5
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• pp.295-300
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• 2012

Background: With growing attention to the aortopathy associated with aortic valve diseases, the number of candidates for accompanying ascending aorta and/or root replacement is increasing among the patients who require aortic valve replacement (AVR). However, such procedures have been considered more risky than AVR alone. This study aimed to compare the surgical outcome of isolated AVR and AVR combined with aortic procedures. Materials and Methods: A total of 86 patients who underwent elective AVR between 2004 and June 2010 were divided into two groups: complex AVR (n=50, AVR with ascending aorta replacement in 24 and the Bentall procedure in 26) and simple AVR (n=36). Preoperative characteristics, surgical data, intra- and postoperative allogenic blood transfusion requirement, the postoperative clinical course, and major complications were retrospectively reviewed and compared. Results: The preoperative mean logistic European System for Cardiac Operative Risk Evaluation (%) did not differ between the groups: $11.0{\pm}7.8%$ in the complex AVR group and $12.3{\pm}8.0%$ in the simple AVR group. Although complex AVR required longer cardiopulmonary bypass ($152.4{\pm}52.6$ minutes vs. $109.7{\pm}22.7$ minutes, p=0.001), the quantity of allogenic blood products did not differ ($13.4{\pm}14.7$ units vs. $13.9{\pm}11.2$ units). There was no mortality, mechanical circulatory support, stroke, or renal failure requiring hemodialysis/filtration. No difference was found in the incidence of bleeding (40% vs. 33.3%) which was defined as red blood cell transfusion ${\geq}5$ units, reoperation, or intentional delayed closure. The incidence of mediastinitis (2.0% vs. 0%), ventilator ${\geq}24$ hours (4.0% vs. 2.8%), atrial fibrillation (18.0% vs. 25.0%), mean intensive care unit stay (34.5 hours vs. 38.8 hours), and median hospital stay (8 days vs. 7 days) did not differ, either. Conclusion: AVR combined with additional aortic or root replacement showed an excellent outcome and recovery course equivalent to that after isolated AVR.

• Childhood Kidney Diseases
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• v.14 no.1
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• pp.32-41
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• 2010

Purpose : Glomerulonephropathy (GN) often manifests as proteinuria and progresses to chronic renal failure without specific therapy. Mesenchymal stem cell (MSC) has been tried as a therapeutic agent in experimental GN, and previous studies showed that administration of MSC concomitantly to the insult inducing GN or via intra-renal administration ameliorated proteinuria. The purpose of this study was to test the therapeutic potential of MSC administered via intravenous route at the time of clinically evident proteinuria. Methods : MSCs were administered intravenously via tail vain into the mice with adriamycin (ADR) induced nephropathy (ADR-GN), two weeks after ADR injection when massive proteinuria was evident. To test the capacity of MSC modulate the cytokine production in the inflammatory milieu, the concentrations of IFN-$\gamma$ and IL-10 were measured in the supernatant of in vitro mixed lymphocyte culture (MLC) with or without additional MSC. Results : MSCs administered intravenously into the proteinuric mice with ADR-GN accelerated the recovery of this experimental GN with disappearance of proteinuria in two weeks when the saline treated (control) mice still showed significant proteinuria. The mice treated with MSC also had a tendency of better survival. Addition of MSC decreased IFN-$\gamma$ and increased IL-10 in the supernatant of MLC. Conclusion : This study showed that MSC had a therapeutic potential even when administered in a more clinically relevant setting into a proteinuric glomerulonephropathy model. Further study to verify the mechanism and long-term safety of this phenomenon is required.

• Childhood Kidney Diseases
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• v.17 no.2
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• pp.149-153
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• 2013

We report the case of a 14-year-old girl, diagnosed with atypical thrombotic microangiopathy (TMA). The patient presented with persistent fever, nausea, and newly developed peripheral edema. Her laboratory findings indicated chronic anemia with no evidence of hemolysis, thrombocytopenia, or elevated serum creatinine level. A few days after hospitalization, acute renal failure and fever worsened, and proteinuria developed. On day 40 of hospitalization, she experienced a generalized tonic seizure for 5 min, accompanied by renal hypertension. Brain magnetic resonance imaging revealed posterior reversible leukoencephalopathy syndrome. After steroid pulse therapy, a renal biopsy was performed because of delayed recovery from thrombocytopenia. The biopsy findings showed features of thrombotic microangiopathic hemolysis with fibrinoid change restricted. Current diagnostic criteria for TMA have focused on thrombotic thrombocytopenic purpura and hemolytic uremic syndrome, and diagnosis is based on the clinical presentation and etiology, with the consequence that idiopathic and atypical forms of TMA can be overlooked. Developing effective tools to diagnose TMA, such as studying levels of ADAMTS13 or testing for abnormalities in the complement system, will be the first step to improving patient outcomes.

• Journal of Yeungnam Medical Science
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• v.18 no.1
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• pp.51-58
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• 2001

Background: Cholestatic hepatitis is failure of bile to reach the duodenum with hepatocellular damage and no demonstable obstruction of the major bile ducts. The prognosis is usually good with recovery in less than 4 weeks after withdrawal of the offending drug. However, a prolonged course lasting over 3 months is possible and, in rare cases, progression to ductopenia with development of a vanishing bile duct syndrome occurs. A differential diagnosis with other causes of Chronic liver disease is needed. Materials and Methods: From January 1991 through January 2000, 14 patients diagnosed as cholestatic hepatitis by liver biopsy were included. The possible causative drug, clinical features, laboratory findings, and progression of cholestatic hepatitis were evaluated. The semiquantitative study of liver lesions was performed by two independent observers. Results: Causes of cholestatic hepatitis are 5 cases of oriental medicine, 3 cases of anti-tuberculosis medication, 1 case of ticlopidine and antibiotics and 4 cases of unknown causes. The clinical features of cholestatic hepatitis were jaundice, itching, urine color change, and general weakness. During 6 to 30 months, LFT of 5 patients showed prolonged elevation. Elevated total cholesterol ${\geq}$250 mg/dL in 6 patients, pheripheral blood eosinophilia in 5 patients, auto-antibody positive in 6 patients were observed respectively. The biopsies showed intralobular bilirubinostasis with a mixed portal inflammatory infiltration. Conclusion: In cholestatic hepatitis, durations of abnormal LFT are variable regardless of causative drugs. If cholestatic hepatitis progresses toward chronic course, viral hepatitis, primary biliary cirrhosis, and autoimmune hepatitis should be differentially diagnosed and sequential liver biopsies are needed.

• The Journal of Korean Institute of Next Generation Computing
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• v.15 no.3
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• pp.7-15
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• 2019

Cloud computing markets are rapidly growing as cost savings and business innovation are being carried out through ICT worldwide. In line with this paradigm, the nation is striving to introduce cloud computing in various areas, including the public sector and defense sector, through various research. In the defense sector, DIDC was established in 2015 by integrating military, naval, air and military computing centers, and it provides cloud services in the form of IaaS to some systems in the center. In DIDC and various future cloud defense systems, It is an important issue to ensure availability in cloud defense systems in the defense sector because system failures such as network delays and system resource failures are directly linked to the results of battlefields. However, ensuring the highest levels of availability for all systems in the defense cloud can be inefficient, and the efficiency that can be gained from deploying a cloud system can be reduced. In this paper, we classify and define the level of availability of defense cloud systems step by step, and propose the strategy of introducing Erasure coding and failure acceptance systems, and disaster recovery system technology according to each level of availability acquisition.