• Journal of Digital Convergence
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• v.12 no.10
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• pp.317-327
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• 2014

To improve the efficiency of wireless channel, IEEE 802.11ac uses the DL MU-MIMO MAC scheme through which an AP transmits multiple frames to different mobile nodes simultaneously. IEEE 802.11ac DL MU-MIMO MAC needs a new step, called as TXOP sharing, between legacy IEEE 802.11n DL SU-MIMO's two operations, the obtaining an EDCA TXOP and the transmitting multiple frames for EDCA TXOP. In the TXOP sharing operation, both wireless channel destinations and frames transmitted for its TXOP period should are determined. So this paper deals with the TXOP sharing for improving IEEE 802.11ac MAC performance. However, the EDCA priority based method mentioned by IEEE 802.11ac standard document not fair among the buffers and the frames of buffers, and occurs in high_loss rate and high_delay about specific buffers. In this paper, we propose a new scheme of the TXOP sharing with sequencing p-AC, s-AC in similar properties, and all S-AC. This method provides a differentiated service without damage of EDCA characteristics.

• Journal of Digital Convergence
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• v.18 no.10
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• pp.33-39
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• 2020

In order to cope with traffic accidents efficiently, the maximum number of traffic accidents, deaths and serious injuries that can occur during the day should be presented quantitatively. In order to examine the characteristics of traffic accidents in different regions, it was divided into the Seoul metropolitan area, Chungcheong area, Gyeongbuk area, Honam area, and Gyeongnam area and was suitable for the generalized extreme value distribution (GEV). The parameters of the GEV distribution were estimated by the L-moments, and the Anderson-Darling test and the Cramer-von Mises test confirmed the suitability of the distribution. According to the analysis, the maximum number of traffic accidents that can occur once every 50 years is 401 in the Seoul metropolitan area, 168 in the South Gyeongsang region, 455 in the North Gyeongsang region, 136 in the Chungcheong region and 205 in the South Jeolla region. Compared to the Seoul metropolitan area, which has a large population and car registration, the number of traffic accidents is relatively high due to the large area, mountainous areas, and logistics movement caused by the industrial complex.

• Journal of Digital Convergence
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• v.18 no.10
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• pp.509-516
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• 2020

The purpose of this study was to examine the effects of a 12-week Resistance exercise Type on Muscle Damaged and Blood Lipid in elderly Women. Study shows researchers randomly divided thirty elderly women into the following 3 Groups such as Control group(CG: n=10), Aquatic Exercise Group(AEG: n=10), circuit exercise group(CEG: n=10). They made each group excercise 3 days a week for 12 weeks. The results were as follows. There was no interaction effect in the TC, LDL-C, HDL-C but there were interaction effects in the Body weight and Body Fat(%). The AEG and CEG decreased than the CG in the Body Weight, Body Fat(%), TC, LDL-C, and increased than the CG in the HDL-C with significant difference. These results were made certain that decreasing the Body Weight and Blood lipid, Increasing the Muscle and HDL-C for elderly women on AEG and CEG. The analysis results of study show the index of TG, CPK, LDH has no significant difference. Besides, It is considerable that the aquatic Exercise and Circuit exercise can prevent and improve the Sarcopenia for elderly women.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.5
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• pp.33-47
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• 2007

In a practical engineering, the equivalent static analysis (E.S.A) and the response spectrum analysis (R.S.A) are generally used for the seismic analysis. The base shears obtained from the E.S.A are invariable no matter how the principal axes of building structures are specified on an analysis program while those from the R.S.A are variable. Accordingly, the designed member size may be changed by how an engineer specify the principal axes of a structure when the R.S.A is used. Moreover, the base shears in the normal direction to the excitation axis are sometimes produced even when an engineer performs a response spectrum analysis in only one direction. This tendency makes the base shear, which is used to calculate the scale-up factor, relatively small. Therefore the scale-up factor becomes larger and it results in uneconomical member sizes. To overcome these disadvantages of the R.S.A, an alternative has been proposed in this study. Three types of example structures were adapted in this study, i.e. bi-direction symmetric structure, one-direction antisymmetric structure and bi-direction antisymmetric structure. The seismic analyses were performed by rotating the principal axes of the example structures with respect to the global coordinate system. The design member forces calculated with the scale-up factor used in the practice were compared with those obtained by using the scale-up factor proposed in this study. It can be seen from this study that the proposed method for the scale-up factor can provide reliable and economical results regardless of the orientation of the principal axes of the structures.

• Journal of the Earthquake Engineering Society of Korea
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• v.12 no.3
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• pp.1-10
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• 2008

The seismic performance of a structure designed without consideration of seismic loading can be effectively enhanced through seismic rehabilitation. The appropriate level of rehabilitation should be determined based on the decision criteria that minimize the anticipated earthquake-related losses. To estimate the anticipated losses, seismic risk analysis should be performed considering the probabilistic characteristics of the hazard and the structural damage. This study presents the decision procedure in which the probabilistic seismic demand model is utilized for the effective estimation and minimization of the total seismic losses through seismic rehabilitation. The probability density function and the cumulative distribution function of the structural damage for a specified time period are established in a closed form, and are combined with the loss functions to derive the expected seismic loss. The procedure presented in this study could be effectively used for making decisions on the seismic rehabilitation of structural systems.

• Korean journal of applied entomology
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• v.45 no.2 s.143
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• pp.195-200
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• 2006

This study was carried out to clarify the biologies and morphological characteristics of Rhynchaenus sanguinipes. Also some chemicals were tested to screen the effective insecticide for the control of the species. Up to date, Zelkova serrata has been hewn as host plant of Rhynchaenus sanguinipes, which shows serious damage in this country. In the present study, Ulmus pumila was first found as host plant in this study. Body lengths of larvae, pupa and adult were 4.53$\pm$0.30 mm, 3.30$\pm$0.42 mm and 2.96$\pm$0.12 mm, respectively. The overwintered adult of the species emerged on early April to late April, and adult of nekt generation emerged on early May to late May, Pupal periods were 10, 7.2, 5.1 and 4 days on 16, 20, 24 and 28$^{\circ}C$, respectively. The lower developmental threshold temperature was 5.8$^{\circ}C$. Four braconid parasitoids were found as natural enemies, which emerged mainly on late April to early June. Insecticidal activities with treatments of fenitrothion 50% EC, indoxacarb 30% WG, ethofenprox 20% EC and thiacloprid 10% SC was investigated against adult of R. sanguinpes, and they showed >90% mortality.

• Korean journal of applied entomology
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• v.54 no.4
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• pp.289-294
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• 2015

Striped flea beetle, Phyllotreta striolata (SFB) and turnip sawfly, Athalia rosae ruficornis (TSF) are two economically important sporadic pests in radish fields on Jeju island. The response of adult SFB and TSF to a mixture of aggregation pheromone, (+)-(6R,7S)-himachala-9,11-diene and host plant volatile, allyl isothiocyanate (HAI), as well as to yellow and blue sticky traps was examined in radish fields. Adult SFB was more attracted to the sticky trap with HAI, regardless of the color of the sticky trap; however, adult TSF was more attracted on the yellow sticky trap than blue, and no effect of HAI was observed. The adult SFB and TSF can be effectively monitored using yellow sticky traps placed 10 cm above the plant canopy. SFB and TSF had 3 and 5 peak times in a year, respectively. The first peak occurred in the middle of March for SFB and mid-late of April for TSF. We expect that the results of the present study can facilitate minimizing the damage caused by the two important pests in commercial radish fields.

• Korean journal of applied entomology
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• v.56 no.4
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• pp.403-412
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• 2017

To investigate the control effect of insect pests by natural enemies, sticky traps were used in commercial tomato greenhouses in Chun-cheon and the experiment fields of Gangwon-do Agricultural Research and Extension Services, Republic of Korea using semi-forcing culture (February to June). We selected low toxicity pesticides, environment-friendly agricultural materials (EFAM), and natural enemies of the study species, combinations of which have been previously used in farms to control insect pests. In this study, Trialeurodes vaporariorum and thrips, which are major agricultural insect pests, were studied in experimental greenhouses. The adult T. vaporariorum population was observed in mid-April and the population of thrips showed occurrences in early April. Regarding seasonal fluctuation, T. vaporariorum peaked in mid-May and thrips peaked after June. one insecticide, spiromesifen suspension concentrate (SC); one fungicide, cyazofamid SC; and two EFAMs containing neem tree extract were shown to be slightly toxic to Encarsia formosa and Orius laevigatus. The results of this study could be used to develop management models using natural enemies of control the insect pests; T. vaporariorum and thrips in semi-forcing culture of tomato.

• Korean Journal of Child Education & Care
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• v.17 no.2
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• pp.1-24
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• 2017

The purpose of this study is to present information about effective parent education method by examining effects of parenting education program on emotional coaching, parenting efficacy, parenting attitude and emotional expression. For this purpose, 43 parents who have a toddler who is financed in H daycare center and Y daycare center in G city of Jeonbuk were selected as research subjects. Among them, twenty - two mothers of infants who are financially supported by H day care center were selected as experiment group and they conducted a total of 8 cycles of emotional coaching parent education program for 120 minutes per week and once a week. For the analysis of collected data, ANCOVA was performed using SPSS 18.0 program. The results were as follows. The parenting program of emotional coaching positively affects mother 's parenting efficacy, parenting attitude and emotional expressiveness. The results of this study can be used as basic data of parent education method which helps the desirable interaction with infant through more specific steps through emotional coaching to parents with toddlers.

• Spatial Information Research
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• v.9 no.2
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• pp.207-225
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• 2001

This study develops a GIS-based system which examines the adequacy of the Groundwater development project before the actual designing of the project. A system environment is constructed in order to efficiently and scientifically manage and analyze data related to Groundwater through a Server/Client environment. For this programs such as GIS S/W ArcVies3.2, RDBMS ORACLE, ArcSDE (Spatial Database Engine) are used. WHPA and AQTESOLV are employed as a underground water simulation program and Scripts, a language for ArcView, is used to develop graphic user interface (GUI). Using the system developed here, we can transfer simulation results obtained by WHPA regarding Groundwater levels in new development projects into GIS. We can also judge whether a Groundwater development project should be permitted through examining overlaps of th effects of the development and comparing with o pollutants. At the same time, the system has a feature of supporting Groundwater development and based designing through judging the proper amount of Groundwater in a new project. It is also possible to easily and quickly prepare charts and reports using the outputs of the system. Since a two-tiered system which shares DB using inter-and intranets is developed, all the departments in the ministry of agriculture and forest and the agriculture base corporation can share accurate, reliable and latest information related to Groundwater.