• Proceedings of the KSME Conference
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• 2001.11b
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• pp.124-130
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• 2001

The heat transfer and flow measurements were made on a cylindrical pedestal mounted on a flat plate with a turbulent impinging air jet. The heat transfer coefficient distributions on the flat plate were measured using the shroud-transient technique and liquid crystal was used to measure the surface temperature. The jet Reynolds number (Re) is 23,000, the dimensionless nozzle-to-surface distance (L/d) from 2 to 10, the dimensionless pedestal diameter-to-height (H/D) from 0 to 1.5, the dimensionless 2nd pedestal diameter-to-height ($H/D_2$) from 0 to 0.4 and the distance from the stagnation point to 2nd pedestal (p/D). The results show that for H/D = 0.5 to 1.5, the Nusselt number distributions on the plate surface exhibit a maximum between $r/d\;{\cong}\;1.0$ and 1.5. The presence of the pedestal appears to cause the flow separation and reattachment on the plate surface, which results in the maximum heal transfer coefficient. Also, for p/D = 2.5 and $H/D_2$ = 0.3, the local Nusselt number in the region corresponding to $r/d\;{\cong}\;1.1$ was increased up to 50% compared to that for $H/D_2=0$.

• Environmental Engineering Research
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• v.20 no.2
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• pp.133-140
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• 2015

The aim of this study was to investigate the bacteriophage removal in various clay minerals and clay-amended soils. Batch experiments in kaolinite, montmorillonite, and bentonite showed that kaolinite was far more effective at the MS2 removal than montmorillonite and bentonite. In kaolinite, the log removal increased from 0.046 to 2.18, with an increase in the adsorbent dose from 0.3 to $50g\;L^{-1}$, whereas the log removals in montmorillonite and bentonite increased from 0.007 to 0.40 and from 0.012 to 0.59, respectively. The MS2 removal in kaolinite-amended silt loam soils was examined at three different soil-to-solution (STS) ratios. Results indicated that the log removal of MS2 increased with an increase in the kaolinite content and the STS ratio. At the STS ratio of 1:10, the log removal of MS2 increased from 2.33 to 2.80 with an increase in the kaolinite content from 0% to 10% in kaolinite-amended soils. The log removals of MS2 at the STS ratios of 1:2 and 1:1 increased from 2.84 to 3.47 and from 3.46 to 4.76, respectively, with an increase in the kaolinite content from 0% to 10%. Results also indicated that the log removals of PhiX174 and $Q{\beta}$ in kaolinite-amended soils were similar to each other, but they were far lower than those of MS2 at all the kaolinite contents. The log removal of PhiX174 increased from 0.16 to 0.32, whereas the log removal of $Q{\beta}$ changed from 0.17 to 0.22 with an increase in the kaolinite content from 0% to 10%.

• Journal of Korean Academy of Nursing
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• v.8 no.1
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• pp.99-110
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• 1978

For the study on occurrence of backache related to types of daily activities in adulthood Nine hundred twenty six adults living in Seoul were randomly selected as subjects from the eight kinds of occupation; housewives, teachers, nurses, officers, physicians, labourers, beauticians & barbers, and students. The purpose of this study was to identify various factors related to backache in daily activities and to apply these factors in clinical situations as well as in the community situations. This survey was conducted from September 21 through October 8, 1976. Under the ten hypothesis designed for this study, the. followings were obtained; 1. Significant difference on occurrence of backache was revealed according to sex difference at 0.5% level. (x$^2$= 27.85, df: 1, p<0.005) 2. Significant difference on occurrence of backache was revealed according to age groups at 2.5% level. (x$^2$= 11.13, df= 3, p<0.025) 3. Significant difference on occurrence of backache was revealed according to types of occupation at 2.5% level. (x$^2$= 18.04, df: 7, p<0.025) 4. Significant difference on occurrence of backache was revealed according to types of movement originated by hand during occupational activities at 1% level. (x$^2$= 14.23, df= 4, p<0.01) 5, Significant difference on occurrence of backache was revealed according to types f movement of legs during occupational activities at 0.5% level. x$^2$= 20.78, df: 3, p<0.005) . No significant difference on occurrence of backache was revealed according to length f daily working hours. . Significant difference on occurrence of backache was revealed according to degree of exercises at the level. x$^2$= 6.01, df= 2, p<0.05) . Significant difference on occurrence of backache was revealed according to sleeping posture at 1% level. x$^2$= 9.61, df: 2, p<0.01). Significant difference on occurrence of backache was revealed according to ordinary pattern of mean posture score at 0.5% level. (t : 4.27, df: 924, p<0.005) 10. Significant difference was revealed mean posture scores according to period of backache history at 0.5% level. (f- ratio = 3.73, df= 4, 562 p<0.005).

• Allergy, Asthma & Immunology Research
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• v.10 no.6
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• pp.662-674
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• 2018

Purpose: Group 2 innate lymphoid cells (ILC2s) have been implicated in the pathogenesis of allergic disease. However, the effect of allergen-specific immunotherapy (AIT) on ILCs remains to be clarified. The aim of this study was to evaluate the levels of ILC subsets in allergic rhinitis (AR) patients in response to house dust mite (HDM)-specific immunotherapy. Methods: We enrolled 37 AR patients undergoing AIT (16 responders and 11 non-responders) for 2 years, 35 HDM AR patients and 28 healthy subjects. Peripheral blood mononuclear cells (PBMCs) were analyzed by flow cytometry to identify ILC subsets. Stimulation of ILC2s with recombinant allergen-specific protein was used to determine ILC2's activation (CD69 expression). Results: Responder AIT patients and healthy subjects had a decreased frequency of circulating ILC2s compared to non-responder AIT and AR patients. Conversely, ILC1s from responder AIT patients and healthy subjects showed increased frequency compared to non-responder AIT and AR patients. The frequency of ILC3s natural cytotoxicity receptor $(NCR)^+$ and $NCR^-$ in responder AIT patients was significantly lower compared to AR patients and healthy subjects. The ILC1: ILC2 proportion in responder AIT patients was similar to that of healthy subjects. PBMCs from patients who were responders to AIT had a significantly lower expression of the activation marker CD69 on ILC2s in response to allergen re-stimulation compared to AR patients, but no difference compared to non-responder AIT patients and healthy subjects. Conclusions: We propose that AIT might affect ILC responses. The activation of ILC2s was reduced in AR patients treated with AIT. Our results indicate that a relative ILC1/ILC2 skewed response is a possible key to successful AIT.

• The KIPS Transactions:PartB
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• v.17B no.1
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• pp.31-36
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• 2010

After the launch of MPEG-2, it is widely used in multimedia applications like a Digital-TV or a DVD. Then, After the launch of H.264 at 2004, it has been expected to replace MPEG-2 and services IPTV and DMB. As we have been used to MPEG-2 devices by this time, we can not access H.264 Broadcast with MPEG-2 device. So We propose a new approach to transcode H.264 video into MPEG-2 form which can facilitate to display H.264 video with MPEG-2 device. To reduce the quality loss by transcoding, we use CPDT(Cascaded Pixel Domain Transcoder) structure. And to minimize processing time, SKIP block, INTRA block and motion vectors obtain from decoding process is employed for transcoding. we use BMA(Boundary Matching Algorithm) to select only one from candidate motion vectors. Experimental results show a considerable improved PSNR with reduction in processing time compared with existing methods.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.12
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• pp.729-738
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• 2014

In this paper, we propose interference avoidance resource allocation scheme based on graph-coloring algorithm to introduce performance gain using spatial reuse in D2D (Device-to-Device) system. By assigning multiple D2D pairs to a single D2D resource, interference from neighboring D2D pairs is inevitable, which leads to performance degradation. Therefore, we first introduce the feedback information and the method considering the amount of information that can be practically provided by a D2D pair. Then, we propose how to construct a graph, which is corresponding to the D2D system, using the feedback information and adopt a graph-coloring algorithm to efficiently avoid interference. Simulation results show that the proposed resource allocation scheme outperforms traditional resource allocation schemes in both overall sum rate and spectral efficiency of D2D system while reducing the outage probability. Moreover, the outage probability, which indicates a failure rate of D2D communication, can be reduced by adopting the proposed scheme.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.E1
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• pp.16-28
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• 2007

An improved method was developed to determine gas-phase hydrogen peroxide($H_2O_2$) and organic hydro-peroxides (ROOH) in real-time, The analytical system for $H_2O_2$ is based on formation of hydroxybenzoic acid (OHBA), a strong fluorescent compound. OHBA is formed by a sequence of reactions, photoreduction of Fe(III)-EDTA to Fe(II)-EDTA, the Fenton reaction of Fe(II)-EDTA with $H_2O_2$, and hydroxylation of benzoic acid. By use of this analytical method rather than a previous similar method, Fenton reaction time was reduced from 2 min. to 30s. Air samples were collected by a surfaceless inlet to prevent inlet line losses. With a special arrangement of the sampling apparatus, sample delivery time was drastically reduced from ${\sim}5\;min\;to\;{\sim}20\;s$. The automated system was found to be sensitive, capable of continuous monitoring, and affordable to operate. A comparison of this method with a well-established one showed an excellent linear correlation, validating applicability of this technique to $H_2O_2$ determination. The system was applied to field measurements conducted during summertime of 2004 in Gwangju, South Korea. $H_2O_2$ was found to be a predominant species of peroxides. The diurnal variation of $H_2O_2$ displayed the maximum in early afternoon and the broad minimum throughout night. $H_2O_2$ was correlated positively with ozone, photochemical age, and temperature, however, negatively with $NO_x$ and relative humidity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.5
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• pp.539-545
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• 2016

In this paper, the use of an amplify-and-forward (AF) helper station in a cellular network with device-to-device (D2D) communication links is considered to enhance D2D rates and control the interference caused by D2D users to the cellular network. Two design criteria for the AF helper station are considered to improve the overall system quality-of-service (QoS). One is maximization of the worst D2D user rate under a constraint on interference caused by D2D users to the cellular network and the other is its dual, i.e., minimization of interference caused by D2D users to the cellular network with minimum rate guarantee for each D2D user. It is shown that the considered problems reduce to semi-definite programming (SDP) problems. Numerical results show that the proposed AF helper station significantly improves the system performance.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.2
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• pp.208-211
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• 2016

Device-to-Device communication(D2D) enables devices in proximity to communicate directly without going through the network infrastructure. In particular, D2D communications in a cellular network can improve the spectral efficiency by allowing the reuse of cellular resources. However, it is not easy to maintain the channel quality of the D2D links and to protect the cellular links from the D2D interferences, since the resource allocations for the cellular users will change with time due to the time-varying nature of the cellular channels. To mitigate the performance degradation of D2D links, we propose to exploit unlicensed bands as auxiliary resources when the D2D links share the uplink cellular resources. The effectiveness of the proposed scheme is verified through simulations.

• Journal of the korean society of oceanography
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• v.31 no.2
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• pp.75-88
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• 1996

The analytic and numerical solution of the 1$\frac{1}{2}$-layer and 2$\frac{1}{2}$-layer models are derived. The large coastal-sea level drop and the fast westward speed of the anticyclonic gyre due to strong offshore winds using two ocean models are investigated. The models are forced by wind stress fields similar in structure to the intense mountain-pass jets(${\sim}$20 dyne/$cm^{2}$) that appear in the Gulfs of Tehuantepec and Papagayo in the Central America for periods of 3${\sim}$7 days. Analytic and numerical solutions compare favorably with observations, the large sea-level drop (${\sim}$30 cm) at the coast and the fast westward propagation speeds (${\sim}$13 km/day) of the gyres. The coastal sea-level drop is enhanced by several factors: horizontal mixing, enhanced forcing, coastal geometry, and the existence of a second active layer in the 2$\frac{1}{2}$-layer model. Horizontal mixing enhances the sea-level drop because the coastal boundary layer is actually narrower with mixing. The forcing ${\tau}$/h is enhanced near the coast where h is thin. Especially, in analytic solutions to the 2$\frac{1}{2}$-layer model the presence of two baroclinic modes increases the sea-level drop to some degree. Of theses factors the strengthened forcing ${\tau}$/h has the largest effect on the magnitude of the drop, and when all of them are included the resulting maximum drop is -30.0 cm, close to observed values. To investigate the processes that influence the propagation speeds of anticyclonic gyre, several test wind-forced calculations were carried out. Solutions to dynamically simpler versions of the 1$\frac{1}{2}$-layer model show that the speed is increased both by ${\beta}$-induced self-advection and by larger h at the center ofthe gyres. Solutions to the 2$\frac{1}{2}$-layer model indicate that the lower-layer flow field advects the gyre westward and southward, significantly increasing their propagation speed. The Papagayo gyre propagates westward at a speed of 12.8 km/day, close to observed speeds.