• Journal of the Korean Geographical Society
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• v.28 no.2
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• pp.123-136
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• 1993

The growth of radidly improving computer and information technology has a profound impact upon economical, social and cultural sectors. With the progress of information technology, information-telecommunication services are produced. This service is used in sending the information to order service-users, and search the need information. This case study considers information-telecommunication service as a consumer-innovation. Information telecommunication services are provided by firms involved in collection. HiTEL(High-Telecommunication) service represents a subset of this group in that the collection, processing and transmission is primarily in an electronic from. The purpose of this paper is concerned with examining the spatial diffusion process, the issues, and behavior to used in HiTEL service one of the information-telecommunication services in Kwangju. HiTEL service is one of the typical information-telecommunication services, and is begun in Seoul and Kwangju area from October 1991, and diffusing several cities and regions now. Diffusion process of HiTEL services in Kwangju showed the irregular pattern in major residential areas, particularly Daewei-dong, Dongun-dong present higher adoption rate than other area, and where functioned as a diffusion center, the social and economic characteristics of residential area have a critical effect on diffusion process. The major adoption areas are recently built residential area, apartment districts, and diffusion direction shows two directions according to development of residental area; one is to south, another is from northeast to southwest. In order to understand the use-behavior of HiTEL service, questionary survey was carried out. Most adopters have a concern to actual life, as HiTEL, information of telephonenumber, and Daewoo Dial-Van compared with other information service. But the actual use-frequency of service is very low. In use of Kwangju regional information service, the use-frequency of operator is very low because of the lack of advertisement, the lack of providing information, and the low-concerns for regional information. But most of adopters need the providing of various regional information as regional news, education, medical and cultural events, housing, city-transportation, and job market. Thus, in order to increase and diffuse the HiTEL service, the establishment of diffusion strategies and the scheme for solution of related issues are very important. The direct diffusion strategies are the diffusion of information-mind, establishment of diffusion and education center, providing of regional information. The scheme for solution of related issues revealed in operating process are reduction of rental fee, development of the related technology and services.

• Journal of the Korean Geographical Society
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• v.51 no.2
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• pp.201-217
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• 2016

We accessed the climate change effects on the distributions of warm-evergreen broad-leaved trees (shorten to warm-evergreens below) in the Korean Peninsula (KP). For this, we first selected nine warm-evergreens with the northern distribution limits at mid-coastal areas of KP and climate variables, coldest month mean temperature and coldest quarter precipitation, known to be important for warm-evergreens growth and survival. Next, species distribution models (SDMs) were constructed with generalized additive model (GAM) algorithm for each warm-evergreen. SDMs projected the potential geographical distributions of warm evergreens under current and future climate conditions in associations with land uses. The nine species were categorized into three groups (mid-coastal, southwest-coastal, and southeast-inland) based on their current spatial patterns. The effects of climate change and land uses on the distributions depend on the current spatial patterns. As considering land uses, the potential current habitats of all warm-evergreens decrease over 60%, showing the highest reduction rate for the Kyungsang-inland group. SDMs forecasted the expansion of potential habitats for all warm-evergreens under climate changes projected for 2050 and 2070. However, the expansion patterns were different among three groups. The spatial patterns of projected coldest quarter precipitation in 2050 and 2070 could account for such differences.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.4 s.95
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• pp.380-388
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• 2005

This paper presents analysis results of the effects of RF filter characteristics on the system performance of impulse radio. The impulse radio system transmits modulated pulses having very short time duration and information can be extracted in receiver side based on cross-correlation between received and transmitted pulses. Accordingly, the pulse distortion due to in-band group delay variation can cause serious system performance degradation. In general, RF bandpass filters inevitably cause group delay difference to the signal passing through the filter which is proportional to its skirt characteristic due to its resonance phenomenon. For time as well as frequency domain analysis, small signal scattering parameter $S_{21}$ and its Fourier transform are used to characterize output pulse waveform under the condition that the input and output ports are matched. The output pulse waveform of the filter is predicted based on convolution integral between input pulse and filter transfer function, and resulting BER performances in the BPM and PPM based impulse radio system are calculated.

• Resources Recycling
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• v.29 no.2
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• pp.28-36
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• 2020

To enhance the recycling rate of wasted glass bottles toward recycled aggregates, the study would decide optimal comminution equipment based on the particle size distribution, aspect ratio and equipment energy analysis. The impact, compress and abrasion is type of generated force by comminution. So, hammer crusher, shredder, roll crusher and ball mill have been selected because they have characteristic which is each type of force. As a result of the particle size analysis of each product, only the shredder product satisfied concrete and asphalt aggregate quality standard condition. Also, as a result of aspect ratio analysis using Imaging software program (Image J, National institute of health), most of size fraction is confirmed under 1.6 value. It was confirmed that the product has low dangerousness and satisfying to shpage index. Also, the particle reduction ratio against input energy of shredder product was the most high. Therefore, we can decide that the optimal equipment which applicable for comminuting waste glass bottle in certain particle size under 10mm is shredder. The result of study will make contribution to increasing energy efficiency of comminution processing and competitiveness of product.

• Resources Recycling
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• v.29 no.3
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• pp.11-23
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• 2020

This study aims to investigate breakage and liberation characteristics of iron ore from Shinyemi mine, Jeongseon by ball mill. Parameters of breakage functions for three grade samples of iron ore were obtained using single-sized-feed breakage test and back-calculation based on nonlinear programming. The results showed that with the increase in the grade of iron ore, the breakage rate factor decrease whereas the particle size sensitivity decreases. This results from retardation of microcrack-propagation by magnetite grain in the ore. Breakage distribution analysis showed that the breakage mechanism appear to be impact fracture dominant with the increase of grade owing to the stress distribution effect by magnetite grain. Degree of liberation (DOL) increased with the increase in grade and decrease in particle size, respectively. Using the breakage function and size-DOL relationship, a model that can predict time-dependent-DOL is established. When scale-up factors from operating condition are available, the model is expected to be capable of predicting size and DOL with time in actual mining process.

• Journal of Energy Engineering
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• v.23 no.2
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• pp.93-101
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• 2014

How to determine the extent of national energy security? In this paper, we estimate it by comparative analysis of South Korea and other OECD countries in terms of energy diversity (fuel diversity). Energy security consists of 4 key factors such as availability, accessibility, acceptability, affordability. Especially the importance of accessibility can grow as local imbalance of supply and demand increases. As a proxy of the accessibility, fuel diversity can be a significant indicator to estimate a measure of energy security. In this paper, we use Shannon-Wiener index to measure energy diversity. If fuel diversity increases, the stability of energy security also should increase, because of the smoothing effect to lessen dependence on key energy sources. In 2012 Korean growth rate of H-index (energy diversity) is 18.38%, which is higher than other OECD countries. However, Korean H-index itself is 1.93, lesser than other countries. Shift from oil to coals/gas within fossil fuels has more impact on H-index than weight transition from fossil fuels to renewable energies in Korea. We conclude that more renewable energy is an effective solution to achieve higher energy diversity and ultimately higher energy security as the same as the German case.

• The Journal of Engineering Geology
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• v.24 no.1
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• pp.91-98
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• 2014

This paper aims to calculate the increase in groundwater quantity following groundwater dam construction, and to assess its impact on surface water. In the study area of Osib-cheon, Yeongdeok, we estimated groundwater quantity, groundwater level, and effective porosity, and examined surface water fluctuations with respect to the increased groundwater quantity based on the flow duration. The results reveal that the increased groundwater quantity was at most $91,746m^3$ in the total drainage basin of the groundwater dam, and the reduced groundwater quantity was at most $11,259m^3$ in the lower zone of the groundwater dam. Therefore, the total groundwater resources secured was $80,487m^3$ and the decrease in groundwater quantity was just 12.27% of the amount of increase. There were changes in discharge rate by up to $3.00{\times}10^{-2}m^3/s$, as deduced from an analysis offlow duration as a result of groundwater dam construction. The overall difference between before and after construction of the dam was almost insignificant compared with the previous dam. The present results indicate that dammed groundwater can serve as an alternative water resource with sufficient quantity.

• Science of Emotion and Sensibility
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• v.17 no.3
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• pp.107-116
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• 2014

In the current study, it is suggested that when two emotions are presented through cross-modality, such as auditory and visual, incongruence will influence arousal, recognition, and recall of subjects. The first hypothesis is that incongruent cross-modality does not only increase arousal more than the congruent, but it also increases recall and recognition more than congruent. The second hypothesis is that arousal modulates recall and recognition of subjects. To demonstrate the two hypotheses, our experiment's conditions were manipulated to be congruent and incongruent by presenting positive or negative emotions, visually and acoustically. For dependent variables, we measured recall rate and recognition rates. and arousal was measured by PAD (pleasure-arousal-dominance) scales. After eight days, only recognition was measured repeatedly online. As a result, our behavioral experiment showed that there was a significant difference between arousal before watching a movie clip and after (p<.001), but no difference between the congruent condition and incongruent condition. Also, there was no significant difference between recognition performance in the congruent condition and incongruent condition, but there was a main effect of the clips' emotions. Interestingly after analyzing recognition rates separately depending on clips' emotions, there was a significant difference between congruent and incongruent conditions in the only negative clip (p= .044), not in the positive clip. In a detailed result, recognition in the incongruent condition is more than in the congruent condition. Furthermore, in the case of recall performance, there was a significant interaction between the clips' emotions shown in the clips and congruent conditions (p=.039). Through these results, the effect of incongruence with negative emotion was demonstrated, but an incongruent effect by arousal could not be demonstrated. In conclusion, in our study, we tried to determine the impact of one method to convey a story dramatically and have an effect on memory. These effects are influenced by the subjects' perceived emotions (valence and arousal).

• Korean Journal of Agricultural and Forest Meteorology
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• v.11 no.3
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• pp.100-110
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• 2009

'Hongro' is one of the important mid-season apple cultivars bred in Korea. The recent occurrence of water core in Hongro and the consequent problems motivated this study. The objectives of our study were to investigate the influence of air temperature during the growing period on water core occurrence in Hongro and to provide methods to mitigate its impact. Based on our field experiments for three years, the results indicated that the occurrence of water core disorder was due to the prolonged exposure to high temperature ($T_a$) of >$30^{\circ}C$ during the ripening period. The rates of occurrence of water core disorder were higher in the fruit whose weight was more than 300g or those located outside the tree canopy and thus exposed to stronger solar radiation. In terms of mitigating the water core occurrence, the application of spraying $CaCl_2$ four times from late July to August was effective. Furthermore, between 1 and 15 August when the rate of occurrence was high with $T_a$ (from 3:00 to 5:00 p.m.) >$30^{\circ}C$, the micro-water sprinkling for 30 minutes starting at 6:00 p.m. with a supplementary spray conducted two hours after the first application drastically reduced the water core occurrence.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.9
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• pp.6397-6402
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• 2015

This research was performed to review operating parameters, optimum condition and check characteristic of microbubble generation for using bubble size distribution according to venturi specification. Optimum operating condition have airflow rate 0.3 LPM, 3 bar(pressure tank) and connecting nozzle directly(without valve), it is advantageous to generate microbubble. In case of characteristic of microbubble generation according to venturi specification, effect that nozzle specification affects bubble size distribution is low impact. But considering performance aspects, when using nozzle that throat diameter 3-4 mm, $D_{50}$ are $54.98-61.19{\mu}m$(D3L15, D4L15), fraction of bubble less than $50{\mu}m$ are 0.326, 0.345. And it is superior to others. Besides, $D_{50}$ and fraction of bubble less than $50{\mu}m$ of throat length 20 mm are $49.40-54.98{\mu}m$, 0.447, respectively And nozzle that throat length 20 mm is relatively tendency to generate microbubble stably.