• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.4C
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• pp.451-457
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• 2006

A peer-to-peer(P2P) network is inherently vulnerable to malicious attacks from participating peers because of its open, flat, and autonomous nature. This paper addresses the problem of effectively defending from active attacks of malicious peers at bootstrapping phase and at online phase, respectively. We propose a secure membership handling protocol to protect the assignment of ID related things to a newly joining peer with the aid of a trusted entity in the network. The trusted entities are only consulted when new peers are joining and are otherwise uninvolved in the actions of the P2P networks. For the attacks in online phase, we present a novel message structure applied to each message transmitted on the P2P overlay. It facilitates the detection of message alteration, replay attack and a message with wrong information. Taken together, the proposed techniques deter malicious peers from cheating and encourage good peers to obey the protocol of the network. The techniques assume a basic P2P overlay network model, which is generic enough to encompass a large class of well-known P2P networks, either unstructured or not.

• Korean Journal of Veterinary Research
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• v.54 no.3
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• pp.139-146
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• 2014

Jeotgal (salted seafood) has been one of major fermented foods in Korea for long time. Although there are many studies about Jeotgal in various aspects of food, its immunological importance on hosts has not been elucidated yet. In this study, we investigated if several bacteria isolated from Jeotgal may modulate the function of dendritic cells (DCs), powerful antigen-presenting cells equipped with special immunological capabilities. 4 Jeotgal bacteria were selected as representatives and used for experiments. To treat viable DCs, those bacteria were killed at $60^{\circ}C$ for 30 min. The viability of DCs treated with Jeotgal bacteria was verified and two isolates significantly induced high production of interleukin-12, a representative cell-mediated cytokine of DCs. Surface activation and maturation markers (MHC class II, CD40, CD86) of DCs were analyzed by flow cytometer. In addition, the treated DCs showed significantly high lymphocyte stimulatory capability compared to control DCs based on allogeneic mixed lymphocyte reactions. These observations suggest that Jeotgal isolates can function as immunostimulating bacteria in hosts, like Lactobacillus. Taken together, these experimental evidences may broaden the use of Jeotgal isolates in immunological fields in addition to as a fermented food.

• Education of Primary School Mathematics
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• v.23 no.4
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• pp.191-206
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• 2020

The purpose of this study was to find an implication for a direction to improve professional development in mathematics by exploring elementary school teachers' perception of the need for professional development in mathematics. To this end, 4 elementary school teachers were organized into one focus group, and group discussion materials were collected and analyzed based on cases of mathematics professional development needs. As a result of the study, the elementary school teachers' perception that the need for professional development in mathematics is both unnecessary and necessary. The perception of unnecessary was influenced by the easy level of elementary school mathematics content and the ease of teaching. Also, the perception of necessary factors were considering various aspects of mathematics teaching, changing the accumulation of failures in mathematics classes, maintaining authority of students, demand for class improvement due to social change, the impact of school work, the influence of the community of professional development and peers in school, and efforts to grow as teachers. Based on these results, the author discussed ways to promote teachers' participation in mathematics professional development by considering elementary school teachers' perceptions of the need of mathematics professional development.

• The Korean Society of Law and Medicine
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• v.15 no.2
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• pp.63-89
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• 2014

In 1976, the Dalkon Shield-intrauterine device injured several thousand women in U.S.A. which caused the changes of medical deivce regulation. The Medical Device Regulation Act or Medical Device Amendments of 1976 (MDA) was introduce. As part of the process of regulating medical devices, the MDA divides medical devices into three categories. The class II, and III devices which have moderate harm or more can use the section 510 (k), premarket notification process if the manufacturer can establish that its device is "substantially equivalent" to a device that was marketed before 1976. In 21 U.S.C. ${\S}$ 360k(a), MDA introduced a provision which expressly preempts competing state laws or regulations. After that, the judicial debates had began over the proper interpretation and application of Section 360(k) In February 2008, the U.S. Supreme Court ruled in Riegel v. Medtronic that manufacturer approved by the Food and Drug Administration (FDA)'s pre-market approval process are preempted from liability, even when the devices have defective design or lack of labeling. But the Supreme Court ruled in Medtronic Inc. v. Lora Lohr that the manufactures which use the section 510 (k) process cannot be preempted and in Bausch v. Stryker Corp. that manufactures which violated the CGMP standard are also liable to the damage of patient at the state courts. In 2009, the Supreme Court ruled in Wyeth v. Levine that patients harmed by prescription drugs can claim damages in state courts. This may cause a double standard between prescription drugs and medical devices. FDA Preemption is the legal theory in the United States that exempts product manufacturers from tort claims regarding Food and Drug Administration approved products. FDA Preemption has been a highly contentious issue. In general, consumer groups are against it while the FDA and pharmaceutical manufacturers are in favor of it. This issues also influences the theory of product liability of U.S.A. Complete immunity preemption is an issue need to be more declared.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.9
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• pp.814-821
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• 2015

The STEP Cube Lab. classified as a pico-class satellite has been successfully developed as a flight model(FM) to be launched in 2015. Its mission objective is to perform the on-orbit verification of fundamental space core-technologies. In this study, a thermal design concept based on the passive method to achieve the mission objective is introduced. The effectiveness of the thermal design and performance of the satellite has been verified through the acceptance level thermal vacuum test. In addition, to improve the reliability of thermal mathematical model, correlation was performed using the results of thermal balance test. This paper describes a series of process for the thermal vacuum test on the STEP Cube Lab. FM.

• Preventive Nutrition and Food Science
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• v.21 no.3
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• pp.202-207
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• 2016

The aim of this study was to investigate the association of CD36, a class B scavenger receptor, rs6969989 polymorphism with the serum lipid profiles in Korean women, together with their modulation by oily fish consumption. Subjects were participants from the Korean Genome Epidemiology Study (KoGES), which was initiated in 2001 as a large-scale. A total of 4,210 women aged 39 to 70 were included in this study. Data were collected using self-administered questionnaires, anthropometric measurements, and blood chemical analysis. Dietary intake was analyzed using a semi-quantitative food frequency questionnaire. The minor allele frequency for rs6969989 was found in 12% of this population. Homozygotes minor G allele at the rs6868989 exhibited significantly higher high density lipoprotein cholesterol (HDLC) concentrations (P-trend=0.043) and lower fasting glucose (P-trend=0.013) than major allele A carriers. The risk of low HDL-C was significantly lower in homozygotes for the G allele than the A allele carriers (P-trend=0.032). Gene-diet interaction effects between rs6969989 and oily fish intake were significantly associated with the risk of dyslipidemia (P-interaction=0.004). Subjects with homozygotes minor G allele and high oily fish intake generally had a lower risk of dyslipidemia than did those with major allele homozygotes and low oily fish intake. These findings supported that oily fish consumption may modulate the contributions of CD36 rs6969989 on genetic predisposition to the risk of dyslipidemia.

• Imaging Science in Dentistry
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• v.43 no.4
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• pp.219-225
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• 2013

Purpose: The purpose of this study was to determine the prevalence of missing and impacted third molars in people aged 25 years and above. Materials and Methods: The study sample of 3,799 patients was chosen randomly from patients who visited Pusan National University Dental Hospital and had panoramic radiographs taken. The data collected included presence and impaction state, angulation, and depth of impaction of third molars, and radiographically detected lesions of third molars and adjacent second molars. Results: A greater percentage of men than women retained at least one third molar. The incidence of third molars decreased with increasing age. The incidence of partially impacted third molars greatly declined after the age of 30. Vertically impacted maxillary third molars and horizontally impacted mandibular third molars were most frequent in all age groups. Among the maxillary third molars, those impacted below the cervical line of the second molar were most frequent in all age groups, and among the mandibular third molars, deeply impacted third molars were most frequent in those aged over 40. Dental caries was the most common radiographic lesion of the third molars. Mesioangularly impacted third molars showed radiographic lesions in 13 (9.5%) adjacent maxillary second molars and 117 (27.4%) mandibular second molars. Conclusion: The number of remaining third molars decreased and the percentage of Class C depth increased with age. Caries was the most frequent lesion in third molars. Partially impacted mesioangular third molars showed a high incidence of caries or periodontal bone loss of the adjacent second molar. Regular oral examination will be essential to keep asymptomatic third molars in good health.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.11C
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• pp.10-23
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• 2001

It is difficult to satisfy the QoS(Quality of Service) guarantee which is required by real-time application services only with the Best-Effort(BE) service adopted in the current Internet. Therefore, worldwide research is being made on the method of QoS provisioning. Among them, the QoS guarantee mechanism using the Diffserv(Differentiated Service) was discussed in this paper. First we analyzed how the DiffServ performance was affected by traffic models. For this, we performed the research for the random, bursts, and self-similar traffic modeling method. We then designed and implemented an OPNET simulator, and performed the simulation 7d performance evaluation for diverse input parameters. Based on the results of performance evaluation, it was confirmed that QoS guarantee is possible for the EF(Expedited Forwarding) class with the DiffServ function under every environments considered and the service separation between EF and BE(Best Effort) classes is also possible. We also analyzed the performance variation and dynamic behavior of DiffServ mechanism based on the resource allocation between E? and BE classes in WFQ(Weighted Fair Queueing).

• The korean journal of orthodontics
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• v.48 no.3
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• pp.153-162
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• 2018

Objective: The aim of this trial was to compare the alignment efficiency and intermaxillary arch dimension changes of nickel-titanium (NiTi) or copper-nickel-titanium (CuNiTi) round archwires with increasing diameters applied sequentially to the mandibular arch. Methods: The initial alignment phase of fixed orthodontic treatment with NiTi or CuNiTi round archwires was studied in a randomly allocated sample of 66 patients. The NiTi group comprised 26 women, 10 men, and the CuNiTi ($27^{\circ}C$) group comprised 20 women, 10 men. The eligibility criteria were as follows: anterior mandibular crowding of minimum 6 mm according to Little's Irregularity Index (LII), treatment requiring no extraction of premolars, 12 to 18 years of age, permanent dentition, skeletal and dental Class I malocclusion. The main outcome measure was the alignment of the mandibular anterior dentition; the secondary outcome measure was the change in mandibular dental arch dimensions during 12 weeks. Simple randomization (allocation ratio 1:1) was used in this single-blind study. LII and mandibular arch dimensions were measured on three-dimensional digital dental models at 2-week intervals. Results: No statistically significant difference was observed between NiTi and CuNiTi according to LII (p > 0.05). Intercanine and intermolar arch perimeters increased in the CuNiTi group (p < 0.001). Inter-first premolar width showed a statistically significant interaction in week ${\times}$ diameter ${\times}$ application (p < 0.05). Conclusions: The effects of NiTi and CuNiTi round archwires were similar in terms of their alignment efficiency. However, the intercanine and intermolar arch perimeters, and the inter-first premolar width changes differed between groups.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2000.10a
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• pp.116-122
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• 2000

The molecular modification of antiepileptic drugs and direct synthesis of new drugs with the predetermined antiepileptic properties are perspective. New neurochemical attacking to solve the problem including prevention and inhibition of seizures seems to be related to ginsenosides and ginseng polypeptides. The main study based on the severity of febrile convulsions of rat pups has been done from the earlier investigations of antiepileptical action of ginsenosides between KGTRI and MSU (Chepurnov, Park et al., 1995) with different kinds of experimental models of epilepsy. From the cultured cell line DAN25 of ginseng root, the extracts of ginsenosides made in "BIOKHIMMASH" were studied by the project of preclinical anticonvulsant screening (Stables, Kupferberg, 1997). The inhibition of severity of convulsions, decrease of seizures threshold, decrease of audiogenic seizures in rats of different strains and normalization of cerebral blood flow (measured by hydrogen test) were demonstrated in rats after i.c.v., intraperitoneally and orally administration, respectively. The antiepileptical effects by the combination of compounds from ginseng; were compared with the iuluence of Rg1, Rb1, Rc and with the well known antiepileptical drugs such as carbamazepine, valproic acid. The base for the research is obtained by using the WAG/Rij strain (Luijtelaar, Coenen, Kuznetcova), an excellent genetic model for human generalized absence epilepsy. The improving action of gensinosides was effectively demonstrated on the model of electrical kindling of amygdala of WAG/Rij rats with genetically determined absences, and the influences of ginsenosides on the slow wave discharges have also been being investigated. The different characteristics of a kindling process exerted in the sex-different region of the amygdala and demonstrated that the level of sex steroids and content of neurosteroids in amygdaloid tissue can modify the development of seizures. The chemical structures of ginsenosides not only have some principal differences from well-known antiepileptical drugs but the Plant Pharmacology gives us unique possibility to develop new class of antiepileptic drugs and to improve its biological activity.