• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.1
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• pp.34-40
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• 2006

This paper proposed power system for new DC 49[V] telecommunication using forward three-phase PWM rectifier power factor and efficiency for improvement of ripple voltage. Proposed power system for DC 48[V] telecommunication that consists of power conversion devices including switch, inductor and condenser were made between each line, in power inverter device of each switch control turn-on in period of continuity time control to get power factor '1' of sine wave current and on-off of switch lessens peak current that was happened and got conversion efficiency 92.1[%] composing in PWM rectifier of forward form instead of general PWM rectifier. Also, harmonic input regulation value(IEC61000-3-2 Class-As) satisfy input current and reduce ripple factor of output voltage in state that distortion of three-phase supply is overlapped each other.

• Journal of The Korean Society of Grassland and Forage Science
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• v.16 no.3
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• pp.190-198
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• 1996

This experiment was conducted to evaluate the forage yield and quality potential of Festulolium braunii (Festuca pratensis Huds. $\times$ Lolium multiflotum Lam) as forage source in Korea. The experimental design was a split plot design with four replications from Feb. 1994 to Jan. 1996 at Hohenheim uniwrsity. Main plots were three forage species {Fesruca pratensis(Cosmos), Lolium mult~~orum(Lemtal) and Festulolium braunii(Pau1ita)) and subplots were three N levels (150,300 and 450kgha). No differences in dry matter(DM) yields were noted between Festulolium braunii and Lolium multj7orum, but DM yields for Festulolium braunii was 138 more than for Fesruca prafensis(P<0.01 ). Total DM yields over all species increased linearly with increasing N levels. The peak of DM yields over 2 years mean at 450kglha N levels were higher for Lolium mulriJotum(l5,724kg) than for Festulolium braunii(14,730kg) and for Festuca pratensis(l3,68 l kg) (P<0.01). OMD, ME, NEL and other minerals of Fesrulolium braunii were slightly higher and CP, Ca and Mg slightly lower than thsoe of Fesruca pratensis, but CP, OMD, NEL and minerals were absolutly higher for Fesrulolium braunii than for Lolium mulriflorum(P<0.01). It appears that Festulolium braunii has higher potential for improvement of the forage quality than Fesruca prarensis or Lolium rnulrijlorum. The content of CP, CF and minerals were increased, wherease OMD, ME and NEL were decreased in all species with increasing N levels. Yields of CP, DOM and NEL over 2 yean mean were increased in all species with increasing N levels. CP, DOM and NEL yields of Festulolium braunii were higher than those of Lolium multiflorum or Festuca pratensis(P

• Journal of The Korean Society of Grassland and Forage Science
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• v.38 no.3
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• pp.150-155
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• 2018

This study was conducted to determine grazing intensity of growing Korean native goats(Capra hircus coreanae) on mountainous pasture. It was carried out to obtain basic information for improvement of mountainous pasture management and establishing feeding system of Korean native goat. A total of 20 goats were grouped by feeding systems [A mountainous pasture grazing group (Concentrated feed of 1.5% body weight, treatment 1, T1, n=10) and a barn feeding group (TMR, treatment 2, T2), n=10] to conduct study from April to September. The average forage productivity of the mountain pasture was $500.9{\pm}61.41kg/ha$. The average dry matter intake in T1 was 0.64 and the calculated grazing intensity was 21 head/ha. In productivity, when the two treatments(T1, T2) were compared, the dry matter intake was about two to three times the difference. The average daily gain per day during the experiment was 63.3 in the mountain pasture and 120 g in barn feeding. When grazing, considering mountainous pasture productivity it is necessary to increase the productivity through proper feeding. The feed costs of black goats raised by grazing on the grassland in the same period showed an average 75% reduction compared to barn feeding. As a result of this study, it can be expected that a considerable reduction of feed costs can be expected in the breeding of Korean native black goat using the mountain pasture.

• Journal of the Korean Operations Research and Management Science Society
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• v.40 no.1
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• pp.91-116
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• 2015

This study aims to provide public sectors with eco-efficiency information. To implement the purposes of the study, environmental and economic variables of Eco-Efficiency were identified through decision tree model, then the relative Eco-Efficiencies of 243 public sectors were evaluated through input-oriented DEA (Data Envelopment Analysis) model. Specifically, the amount of public purchasing per a staff and the amount of energy use per a staff were considered as input factors. Sales per a staff was considered as output factor. The result shows that most of the public sectors (94.2%) were evaluated as "inefficient" taking into consideration of average value, 0.501 from market-based public corporations, 0.288 from local public corporations, 0.28 from quasi-market-based public corporations, 0.269 from fund-management-based quasi-governmental institutions, 0.09 from non-classified public institutions, and 0.078 from commissioned-service-based quasi-governmental institutions. Furthermore, it is possible to establish a plan for internal Eco-Efficiency improvement based on information of the reference set. In order to improve the Eco-Efficiency in the public sectors in the long term, environmental impacts of the overall public sectors' operations (e.g., energy saving, water saving, waste reduction, and purchasing of green products) needs to be properly proposed in consideration of BSC (Balanced Scorecard) indicators of public sectors.

• Journal of Korean Tunnelling and Underground Space Association
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• v.4 no.4
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• pp.261-276
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• 2002

Recently, for the purpose of choosing reasonable and economical construction, the decision making analyses, such as VE (Value Engineering) and LCC (Life Cycle Cost), are generally performed. But, these methods have some limitations for the application to subway tunnel construction method. So, the AHP (Analytical Hierarchy Process) analysis is applied to determine relative importance for obtaining objectivity in quantitative analysis. And, the LCSC (Life Cycle Social Cost) method is developed to account for the social loss and risk by tunnel construction. From the case of the subway ${\bigcirc}{\bigcirc}$ lot, those methods are very useful to decision making analysis. And, in that case, both quantitative and quantitative analysis appraisement, the drilling and blasting method is evaluated useful alternative proposal in comparing with the cut and cover method.

• Structural Engineering and Mechanics
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• v.63 no.4
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• pp.567-574
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• 2017

Sedimentation tanks are essential structures to filter the suspended sediments in the inlet flow which are constructed at the inlet of the basins forked from rivers and irrigation canals. The larger the constructed tank, the better the sedimentation process is conducted. However, the construction and dredging costs increase. In this regard, improving the performance and sedimentation efficiency seem necessary by alternative methods. One of these effective methods is using baffle plates. Most of the studies carried out in this field are on the use of these baffles in the primary and secondary sedimentation tanks. Hence, this study is carrier out with the objective of increasing the retention efficiency in the irrigation sedimentation tanks using baffles. To reach this goal, the experiments were carried out in a flume with length 8 meters, width 0.3 meters, and height 0.5 meters, considering a sedimentation tanks with a length of 3 meters, in three different inlet concentration, three flow rates and three Froude numbers. The baffles were mounted at the bottom of the tank and the effects of the angle, height and position in the tanks were investigated. The results showed that on average, employing the baffles increased the sedimentation efficiency 5 to 6% and the highest value was obtained for angle 60 with respect to the flow direction. According to the results of this study, the most favorable height and position of these baffles were obtained to be in 40% of the depth of the flow and 50% of the length of the sedimentation tank, respectively. Also, by increasing the number of baffles, the sedimentation efficiency decreased. Regarding the sedimentation regions in this case, more than 80% of the settled sediments were observed in the middle of the tank measured from the inlet.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.9
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• pp.1368-1372
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• 2014

Several studies arduously reported that gayal (Bos frontalis) is an independent bovine species. The population size is shrinking across its distribution. In Bangladesh, it is the only wild relative of domestic cattle and also a less cared animal. Their body size is much bigger than Bangladeshi native cattle and has prominent beef type characters along with the ability to adjust in any adverse environmental conditions. Human interactions and manipulation of biodiversity is affecting the habitats of gayals in recent decades. Besides, the only artificial reproduction center for gayals, Bangladesh Livestock Research Institute (BLRI), has few animals and could not carry out its long term conservation scheme due to a lack of an objective based scientific mission as well as financial support. This indicates that the current population is much more susceptible to stochastic events which might be natural catastrophes, environmental changes or mutations. Further reduction of the population size will sharply reduce genetic diversity. In our recent investigation with 80K indicine single nucleotide polymorphism chip, the $F_{IS}$ (within-population inbreeding) value was reported as $0.061{\pm}0.229$ and the observed ($0.153{\pm}0.139$) and expected ($0.148{\pm}0.143$) heterozygosities indicated a highly inbred and less diverse gayal population in Bangladesh. Prompt action is needed to tape the genetic information of this semi-domesticated bovine species with considerable sample size and try to investigate its potentials together with native zebu cattle for understanding the large phenotypic variations, improvement and conservation of this valuable creature.

• The Journal of the Korea Contents Association
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• v.13 no.3
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• pp.370-380
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• 2013

The research is basically designed to reveal a revisiting behavior for Chung Nam Dae which is inherently characterized sightseeing site. Distributional lag model is tentatively employed to analyze economic factors such as entrance fee and a different level of income. Empirical findings investigate that the revisiting behavior that is associated with a long run effect is more closely connected to the level of national income, but not the level of incomes in Chung Cheong region and Chung Buk province as well. As far as revisiting intention concerns, the entrance fee tends to affect to it by a shorter distributional lag, but the level of income affects to it by way of a pretty much longer distributional lags. To this end, perceived value for Chung Nam Dae should be exposed in order to induce a re-visitor. Such a goal could be attainable by taking care of its system for entrance fee, expanding facilities, re-branding, service improvement, and developing useful programs. Also, setting up an inter-connected networking system with a sightseeing site around is highly recommended.

• The Journal of the Korea Contents Association
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• v.13 no.6
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• pp.361-369
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• 2013

The purpose of this study was to investigate the level of spirituality and stress of clinical practice and to identify the relationship of variables among nursing students. Data were collected from 203 nursing students using self-report questionnaire composed of demographic characteristics and two scales including spirituality and stress of clinical practice. Data were analyzed by frequencies, t-test, ANOVA, Pearson's correlation coefficients using the SPSS program. The mean score for spirituality and stress of clinical practice were above medium level, with the value of 3.18 and 3.42 out of 5 respectively. There were significant mean differences in spirituality according to religion and satisfaction on major while those in stress of clinical practice according to sex and satisfaction on major. Significant negative correlation between spirituality and stress of clinical practice was found. In conclusion, to reduce clinical stress in nursing students, it is necessary to develop and apply educational program for spiritual improvement.

• Journal of the Korean Society for Marine Environment & Energy
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• v.18 no.4
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• pp.291-297
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• 2015

The wave spectrum was generated from wave data measured at the Chagwi-do site in Jeju, where a 10MW class floating wave-offshore wind hybrid power generation system will be installed. The latching control technology (Sheng et al.[2015]) was applied in order to improve the extracted power from WEC (Wave Energy Converter), which is heaving in corresponding irregular waves. The peak period as a representative value of irregular waves was used when we determined the latching duration. From the numerical results in the time-domain analysis, the latching control technology can significantly improve the extracted power about 50%.