• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.4B
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• pp.323-332
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• 2006

In this paper, we consider a WDM based metro ring connecting broadband access networks by using FT-TR (Fixed Transmitter-Tunable Receiver) type access nodes and a new MAC protocol for fair transmission is proposed. The basic channel access scheme is CSMA/CA(Carrier Sense Multiple Access with Collision Avoidance) and the transferred optical slot is changed to be empty slot by SS(Source-Stripping) which drops a packet from ring-rotated slot. This empty slot can be either used to send head-of-line packet in buffer or transmitted to next access node. In former cases, there is the improvement of network throughput, but latter case leads unfairness problem of transmission. Thus the proposed MAC protocol exploits the advantages form tow cases. It gives downstream access nodes chance to use empty slots and limits the unconditional usage of empty slots at upstream access nodes with probability as called p-Persistent MAC protocol. We use a numerical analysis to evaluate bandwidth efficiency and maximum node throughput and compares simulation results in terms of node throughput, fairness factor, transfer delay depending on probability. Under two different FT-TR type architectures for metro ring network the proposed MAC protocol is evaluated and compared.

• Korean Journal of Veterinary Service
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• v.40 no.3
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• pp.201-208
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• 2017

BVDV causes significant infections in ruminants, resulting in reproductive disorders, diarrhea, reduced milk production and enormous damage to farms. In particular, identification and culling of persistent infectious calf is an important task to eliminate infectious nidus in cattle households. However, studies on physiological characteristics of PI bull are still insufficient to understand reproductive effects of BVDV. In this study, one PI bull was confirmed in herd and complete blood analysis was performed. The lymphocyte count of PI at age 4 was below the normal range and the number of WBCs was also in the lower level of normal range in blood. The sperm number produced by PI male becomes lower and the viability of fresh sperm comes to poor with ages (P<0.05). The sperm abnormality was also increased, especially in nuclear vacuoles of head and droplets of midpeace (P<0.05). The PI male becomes infertile due to poor semen quality at age 4. With these results, we concluded that BVDV in PI bull cause decreased sperm cell and abnormality in semen so causes infertility. However, it appears that BVDV could not be transmitted by indirect contact of PI bull, because there was no evidence of BVDV infection in the herd, when regular vaccination program was applied.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.27 no.4
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• pp.110-120
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• 2014

Objectives : We performed a clinical study to investigate autonomic conditions in persistent allergic rhinitis depending on various pattern identifications and the availability of heart rate variability (HRV) as a pattern identification diagnostic tool. Methods : 32 patients with persistent allergic rhinitis were asked to interview with doctor of Korean Medicine and perform the four pattern questionnaires (Cold-Heat Pattern, Phlegm Pattern, Yin Deficiency pattern, bloodstasis pattern). Then, they were examined their autonomic conditions with heart rate variability test. Results : Patients were classified as three pattern groups (Lung-stomach heat, Lung qi deficiency cold, Lung-spleen qi deficiency) by doctor. In the Lung qi deficiency cold group, Total power of the HRV (TP) and the power of the low frequency component (LF) significantly higher than in the Lung-stomach heat or Lung-spleen qi deficiency group (P < 0.05). Also, Patients were classified as 8 pattern groups (Cold/Heat, Phlegm/Non-phlegm, Yin deficiency/Non-yin deficiency, Bloodstasis/Non-bloodstasis) by four pattern questionnaires. Only in the Yin deficiency group, the power of the low frequency component (LF) significantly lower than in the Non-yin deficiency group (P < 0.05). There were not any significant differences in the rest groups. Conclusions : The result may provide that HRV doesn't reflect well the differences in the various pattern groups, and the HRV's availability is low. Continuous studies are needed to develop the objective and standardized pattern identification diagnostic tool for allergic rhinitis.

• Bulletin of the Korean Chemical Society
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• v.24 no.6
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• pp.792-796
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• 2003

Polychlorinated dibenzo-p-dioxins (PCDDs) are extremely toxic and persistent environmental pollutants. Their chemical reactivities and other physicochemical/biological properties show a strong dependence on the chlorination pattern. With increasing the number of chlorines, dioxin congeners become more electronegative and gain higher electron affinities. The vertical electron affinities (VEA) are related with the LUMO energies of neutral molecules. LUMO energies of all PCDD congeners were calculated at the B3LYP/6-31G** level and those of some selected congeners at the level of B3LYP/6-311G**//B3LYP/6-31G** and B3LYP/cc-pvtz/ /B3LYP/6-31G**. The total energies of neutral and anionic species for dibenzo-p-dioxins (DD), 1469-TCDD, 2378-TCDD, and OCDD were calculated at the level of B3LYP/6-31G**, B3LYP/aug-cc-pvdz, and B3LYP/ aug-cc-pvtz//B3LYP/6-31G**. By using the four congeners with D2h symmetry as reference molecules, we could estimate VEA (B3LYP/aug-cc-pvdz) of 75 PCDD congeners based on the linear correlations between LUMO energy and VEA (B3LYP/6-31G**) and between VEA (B3LYP/6-31G**) and VEA (B3LYP/aug-ccpvtz// B3LYP/6-31G**). Results show that all PCDDs with the number of Cl ≥ 3 have positive electron affinities. The PCDD electron affinity values provided in this work can be a useful data set in understanding the congener-specific reactivities of dioxins in various environmental media.

• Journal of Oral Medicine and Pain
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• v.42 no.2
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• pp.35-43
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• 2017

Purpose: This study aims to evaluate the correlation between joint sounds and radiographic bone change patterns along with clinical symptoms of temporomandibular joint osteoarthritis (TMJ OA) patients. Methods: The patients for this study were over 19 years of age, diagnosed tentatively with TMJ OA. The patients were examined with temporomandibular disorders analysis test and all three radiographs, including panoramic radiography, transcranial radiography, and cone beam computed tomography (CBCT). Information of the patients' age, pain status, joint sound and mouth opening range were collected. And bone change pattern was examined by reviewing panoramic radiography, transcranial radiography and CBCT images. Results: The patients with crepitus had a higher average active mouth opening (AMO) range than patients without crepitus, and the group with bilateral crepitus had a higher average AMO range than the group with unilateral crepitus (p<0.001). And the patient with pain during mastication was increased in the group with clicking than the group without clicking, and the group with bilateral clicking showed a statistically significant increase in the patient with pain during mastication than the group with unilateral clicking (p<0.05). The analytical results of the relevance of crepitus showed a high correlation with bone change observed from each of the three radiographs. And the agreement in bone change findings from 3 groups of paired radiographs showed high agreement (p<0.001). Meanwhile, 77.2% of CBCT findings showed bone change of condyle without crepitus (p<0.001). Conclusions: This study presented significant results in the evaluation of the correlation with crepitus and bone change of TMJ OA patients from panoramic radiography or transcranial projection. However, the accurate assessment is required through CBCT for the patient with complains of persistent pain, limitation of mouth opening, and occlusal change even if the crepitus does not exist.

• Journal of Environmental Science International
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• v.22 no.8
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• pp.1009-1017
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• 2013

Perfluorooctanoic acid (PFOA) and perfluorooctyl sulfonate (PFOS) is a new persistent organic pollutants of substantial environmental concern. This study investigated the potential of magnetic ion exchange resin (MIEX$^{(R)}$) as the adsorbent for the removal of PFOA and PFOS from Nakdong River water. In our batch experiments, we studied the effect of some parameters (pH, temperature, sulfate concentration) on the removal of PFOA and PFOS. The results of sorption kinetics on MIEX$^{(R)}$ show that it takes 90 min to reach equilibrium but the economical contact time and dosage were 30 min and 10 mL/L. An increase in pH (pH 6~10) leads to a decrease in PFOA (2.0%) and PFOS (3.6%) sorption on MIEX$^{(R)}$. The sorption of both PFOA and PFOS decreases with an increase in ionic strength for sulfate ion (${SO_4}^{2-}$), due to the competition phenomenon. An increase in water temperature ($8^{\circ}C{\sim}28^{\circ}C$) in water leads to a increase in PFOA (2.8%) and PFOS (4.3%) sorption on MIEX$^{(R)}$. Based on the sorption behaviors and characteristics of the adsorbents and adsorbates, ion exchange and hydrophobic interaction were deduced to be involved in the sorption, and hemi-micelles possibly formed in the intraparticle pores.

• IMMUNE NETWORK
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• v.7 no.2
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• pp.87-94
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• 2007

Background: Chronic rhino-sinusitis and persistent allergic rhinitis is often cited as risk factor for developing adenoid hypertrophy or adenoiditis, but this relationship has not been studied extensively. In this study, we evaluated the mucosal barrier, squamous changes of ciliated epithelium, IgA secretion and BCL-6 expression in adenoids, and adenoid size. Methods: Six children with allergic rhinitis and sinusitis, nine children with only allergic rhinitis, nine children with only sinusitis and six children without any history of allergic rhinitis and sinusitis were enrolled. H-E stain of adenoid for squamous metaplasia, immunohistochemical study of adenoid for IgA and BCL-6, cytokeratin stain for evaluation of mucosal barrier and lateral view X-ray for adenoid size were performed. ANOVA test was used in the analysis and data showing p value of less than 0.05 were considered significant. Results: The number of ciliated cells had tendency to be decreased and squamous metaplasia had tendency to be increased in three experimental groups (p>0.05). Deterioration of mucosal barrier had tendency to be detected in three experimental groups than control group (p>0.05). BCL-6 had tendency to be increased and IgA secretion had tendency to be decreased in three experimental groups (p>0.05). There is no difference in adenoid size between three experimental groups and control group. Conclusion: Despite the expectation that adenoid would be affectecd by allergic rhinitis and rhino-sinusitis, we found no evidence for influence of adenoid immunity.

• Korean Journal of Environmental Agriculture
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• v.3 no.2
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• pp.16-22
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• 1984

This study was carried out to investigate the stability of dinobuton (2-sec-butyl-4,6-dinitrophenyl isopropyl carbonate) in distilled water and buffer solutions and its persistence in soils. When dinobuton was incubated at $30^{\circ}C$ and $60^{\circ}C$ in distilled water, the half-lives of dinobuton was 28 and 6 days, respectively. The decomposition of dinobuton was, therefore, faster at high temperature than at low temperature. The half-life of dinobuton was about 27 days in the acidic solution $(pH\; 4{\sim}6)$, whereas 10 and 4 days in the alkaline solutions of pH 9, and 10, respectively. Thus dinobuton was stable in acidic solution, and unstable in alkaline solution. Dinoseb (2-sec-butyl-4,6-dinitrophenol), which is produced in the degradation process of dinobuton, was produced in small amounts in distilled water and buffer solutions. The half-life of dinobuton in sterilized soil was about 16 days longer than in non-sterilized soil. Dinoseb was also more persistent in sterilized soil than in non-sterilized one.

• Korean Journal of Environmental Agriculture
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• v.2 no.2
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• pp.65-72
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• 1983

The effects of soil factors, pesticide application levels and environmental factors on the degradation of two carbamate insecticides, BPMC and carbofuran, in soil were studied under flooded and non-flooded conditions. The degradation patterns of BPMC or carbofuran were similar in flooded and non-flooded soils. It was also found that carbofuran was more persistent than BPMC in the test soil. Regards to organic contents of soils, high contents of organic matter reduced degradation of either BPMC or carbofuran and high soil pH accelerated degradation of both insecticides. Soil microorganisms seem to play an important role in the degradation of BPMC and carbofuran. Both chemical and biological degradations appear to contribute transformation of BPMC and carbofuran in the flooded soil.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.1A
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• pp.74-80
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• 2000

In this paper, we proposed the MAC protocol and analyzed the performance for CATV/LAN network which was based upon HFC(hybrid optic coaxial) increased abruptly as alternative method of high speed network. Upstream channel which analyzed very deeply for CATV/LAN network have the preferential access property depending upon that position and unidirectional property. To solve this fairness problem, we propose the CSMA-CD/U/P protocol that transm it as $P_i$ probability although data packets is immediately transmitted when it was occurred. As the analytic result and simulation, we obtained $P_i$ value and its average delay time. Also, we get its variance value and queue length distribution. The mean delay time and queue length increase as the load and number of stations increase in the CATV/LAN network.