• Journal of Korean Society of Forest Science
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• v.98 no.5
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• pp.609-617
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• 2009

This study was conducted to investigate ecological indicators of forest degradation after forest fire and clear-cutting in the Siberian larch (Larix sibirica Ledeb.) stand of Mongolia. The species abundance and biodiversity indices were higher in burned and clear-cut stands than those of reference stand, but boreal understory species, such as Vaccinium vitis-idaea, Pyrola incarnata, Linnea borealis and Maianthemum bifolium, completely disappeared and was replaced by sedge species, such as Carex duriuscula, C. lanceolata, C. pediformis, Poa attenuata and P. pratensis. During the research period, temperature increased by an average of $1.6^{\circ}C$ in burned stand and $1.7^{\circ}C$ in clear-cut stand compared to reference stand, but RH sharply decreased up to 15.7% in clear-cut stand. This result indicates that Larix sibirica stand became warmer and drier after forest fire and clear-cutting, and contributed to the abundance of sedge and grass species in the understory. Moreover, intense occupation of tall sedge grass after forest fire and clear-cutting had a vital role as obstacle on natural regeneration of Larix sibirica. The similarity of species composition between reference and burned stands was higher (73.6%) than between reference and clear-cut stands (63.8%). Soil moisture significantly decreased after forest fire and clear-cutting, and the extent of decrease was more severe in the clear-cut stand. The chemical properties at soil organic layer were significantly affected by forest fire and clear-cutting but not the mineral horizons. Inorganic nitrogen of the forest floor significantly decreased in the clear-cut stand ($1.1{\pm}0.4mg{\cdot}kg^{-1}$) than that of the burned ($4.5{\pm}2.3mg{\cdot}kg^{-1}$) and reference stands ($5.0{\pm}2.3mg{\cdot}kg^{-1}$). Available P of the forest floor significantly increased after fire, whereas it decreased after clear-cutting. These results indicate that existence of boreal understory vegetation, and changes in soil moisture and available P are distinct attributes applicable as ecological indicators for identifying forest degradation in Mongolia.

• The Journal of Society for e-Business Studies
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• v.16 no.4
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• pp.139-154
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• 2011

Recently Internet keyword search service providers tends to use CPC advertizement method rather than CPM method. However researches how much the CPC method is beneficial to advertisers than CPM method in certain perspectives are insufficient and not performed systematically. So this paper tries to do comparative analysis about the two methods by analyzing the real transactional DB data from an advertizement agency. Due to the difficulties of direct comparison between the two methods because of their different expose positions on the Web and different types of attributes in DB, we did some preprocessing step for the transactional data. From the result of analysis, the click rate of CPC is higher than CPM by 1.3% and the unit cost for the CPC per one click is lower than CPM method by 51 Won. It shows the CPC method is more effective than CPM method for advertizement from the point of advertizement effectiveness (CTR) and advertizement cost (CPC). We hope this research would give useful information to advertisers and marketing managers in making advertizement strategy, marketing decision and budgeting.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.2
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• pp.105-112
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• 2017

In order to satisfy the diffusion of multimedia service in mobile communication and the demand for high-speed communication, it is essential to modify and improve high efficiency, wideband and nonlinear characteristic of multiband power amplifier. This research is designed to implement a single-stub matching circuit as a 2nd harmonic one that meets conditions of the Class-J power amplifier. Low characteristic impedance of the single-stub line is necessary to suit conditions of wideband Class-J. This research uses ceramic substrates having high permittivity to implement the single-stub line with low characteristic impedance, which eventually results in an amplifier satisfying the output impedance terms of Class-J in wideband frequency range. This result attributes to use of GaN HEMT packaged with a 2nd harmonic matching circuit and external fundamental circuit. The measurement results of the Class-J amplifier confirms the following characteristics: more than output power of 50 W(47 dBm) in bandwidth of 1.8~2.7 GHz(0.9GHz), maximum drain efficiency of 72.6 %, and maximum PAE characteristic of 66.5 %.

• Journal of the Korean Institute of Landscape Architecture
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• v.44 no.4
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• pp.66-74
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• 2016

In what way is the urban landscape of North Korea used today, and what features do people prefer in the North Korean landscape? This study analyzed the characteristics of Pyongyang landscapes and their effects, based on an analysis of Western tourists motivation for tourism in North Korea and preferred enjoyment-seeking experiences. Using data from the tourist agency specializing in Western tourism in North Korea and a location based photo-sharing service, the study interprets the visual distinctiveness of Pyongyang landscape. The study concluded that widely known risk to travelers in North Korea is in fact an attraction, making people want to visit directly. However, this risk was mitigated in practical experience by the overall intermediation of the tourism agency and locals' conscious behavior to keep their distance from foreigners. Next, the scope of National ritual attributes was expanded to the locals' daily life as well as large-scale events such as mass games and military parades only if for national holidays. Also, the most preferred factors contributing to North Korean tourism were based on departure from routine through mobilization of the residents. This indicates the extension that the nature of North Korea as a theater state. The Pyongyang landscape represents a world politically isolated, people's congregated motion to display to the world, and people's lives hidden beneath a veil. These visualities fulfill the fantasy of Westerners regarding North Korea. Furthermore, these are superficial images that help create a basis to maintain the North Korea regime.

• Journal of Korean Society of Transportation
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• v.33 no.6
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• pp.584-597
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• 2015

A considerable amount of literature has been published on pedestrian LOS. So far, however, there is a limitation that LOS analysis methodologies has concentrated on quantitative variables such as pedestrian flow rate, speed and space. This paper intended to suggest the accessibility variable which can not be considered on previous study. The factor was defined and quantified using public transport attributes in particular. This study was carried out in three phases: 1. defined accessibility employing public mode location and service information. 2. investigated the relationship between accessibility and pedestrian flow rate 3. developed the model to establish the factors affected to pedestrian LOS. The results showed that accessibility, walkway attribute and land use type affected the pedestrian LOS. Especially, accessibility and commercial area ratio had negative relationship with LOS. Futhermore, pedestrian LOS declined when obstacle of bus station located on the walkway. On the contrary, LOS was upgraded when sufficient effective width or residential area was secured. These results can receive considerable critical attentions related to determination of pedestrian LOS or effective walkway width.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.5
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• pp.595-603
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• 2019

To alleviate the demand on private car that is constantly increasing, Busan Metropolitan City (BMC) has established Bus Rapid Transit (BRT) to revitalize public transportation. But there are no unified lane system between BRT and general bus stations, which makes off-lane turning general bus to contribute to congestion. And as the bottleneck phenomenon at entrance/exit accelerates the congestion, there has been huge dissatisfaction among commuting drivers. Therefore, this study identifies efficient methods to operate better through measuring civilian awareness. We evaluate both satisfaction and drawbacks on BRT service with Importance-Performance Analysis (IPA). We first distinguish the groups by the awareness on BRT and their main transit usage, and then clarify the difference between the groups. And as a result, the group who is positive to BRT and uses buses often demands improvement in bus indoor comfort and curbing jaywalking. On the other hand, group who is negative to BRT and uses private cars often demands improvement in lane changing and the moving speed of private cars. We next examines the groups with MDPREF, one method of Multidimensional Scaling (MDS). And we have clarified that the evaluating criteria and the individual attributes of the groups corresponds very well.

• International Area Studies Review
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• v.22 no.1
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• pp.141-159
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• 2018

The study aims to explore the factors that affect the value perception, satisfaction, and frequency of smart phone taxi applications in Shanghai, China, and commuters. According to a survey conducted on the actual use of taxi application, the majority of the customers responded that they have been using taxi apps for more than one or two years, and the results showed that they use taxi apps once or twice a week. It also showed that the actual use of taxi apps varies depending on their age and academic background. Among the value attributes of smart phone taxi applications, the respondents perceived ease of use as the highest at 4.41 points out of 5 point scale, while the risk perception was the lowest at 3.34 points. Finally, when social demographic characteristics and the nature of taxi app use were controlled, the value perception variables had a significant influence on taxi application satisfaction. The higher the perception of service quality, usefulness, and system usability, the higher the satisfaction levels were. In particular, the impact of perceived usefulness and system usability perception was high.

• 한국노년학
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• v.36 no.3
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• pp.711-726
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• 2016

The purpose of this study was to analyze to 1) the differences according to demographic characteristics 2) select the type-specific communities online channels of the baby boomer customers group, who ever search for restaurant information through on-line for the previous three months. The study was based on a total of 280 samples obtained from on-line networking service users in a metropolitan area from April 15 to 30, 2016. The major findings are as follows. The data were analysed using frequency, factor analysis, cluster analysis and ${\chi}^2test$. According to the results of factor analysis, on-line utilizing attributes were separated into three factors: commitment of useful information, activity of leading on-line, and habit. The based on a factor analysis, cluster analysis was adopted to segment baby boomer customers. The identified four clusters showed in using on-line: type of active utilization, habit, seeking information and passive utilization. The clusters had significant differences in gender and monthly income by demographics. All of four clusters selected blog, face book, twitter in turn through the personal on-line channels. Cluster type of active utilization and habit selected restaurant home pages, restaurant blog, restaurant face book, restaurant twitter in turn through the public on-line channels. Cluster type of seeking information and passively utilization selected restaurant home pages, restaurant blog, restaurant twitter, restaurant face book in turn through the public on-line channels. Implications and future research were also discussed.

• Smart Media Journal
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• v.8 no.3
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• pp.70-79
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• 2019

Implementing UX design that meets user expectations has become an important variable that determines the prominence of smart home appliances. This study addresses the UX design evaluation issues in mobile application development of smart home appliances. As an experimental research subject, the UX design evaluation contents were set up for the mobile application of , the demand of which is surging recently. The purpose of the research is to explore the significance of the UX design user evaluation method in smart home applications, and to suggest how to achieve the mixing of quantitative and qualitative evaluation methods. The main findings are as follows. First, we found that user evaluation can positively impact the direction of UX design. Secondly, we found that the mixing of 'quantitative' and 'qualitative' methods works complementarily to UX design evaluation. Research implications are as follows. The UX design evaluation process can be performed efficiently as long as we distinguish between the roles of quantitative evaluation and qualitative evaluation. For example, through qualitative evaluation such as 'Honeycomb model', can be identified in terms of 'exploratory', and through qualitative evaluation such as 'in-depth user interview', can be identified in terms of 'assessment' and 'validation'.

• Journal of Internet Computing and Services
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• v.19 no.6
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• pp.31-40
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• 2018

With the development of IT technology recently, medical information systems are being constructed in an integrated u-health environment through cloud services, IoT technologies, and mobile applications. These kinds of medical information systems should provide the medical staff with authorities to access patients' medical information for emergency status treatments or therapeutic purposes. Therefore, in the medical information systems, the reliable and prompt authentication processes are necessary to access the biometric information and the medical information of the patients in charge of the medical staff. However, medical information systems are accessing with simple and static user authentication mechanism using only medical ID / PWD in the present system environment. For this reason, in this paper, we suggest a dynamic situation authentication mechanism that provides transparency of medical information access including various authentication factors considering patient's emergency status condition and dynamic situation authentication system supporting it. Our dynamic Situation Authentication is a combination of user authentication and mobile device authentication, which includes various authentication factor attributes such as emergency status, role of medical staff, their working hours, and their working positions and so forth. We designed and implemented a dynamic situation authentication system including emergency status decision, dynamic situation authentication, and authentication support DB construction. Finally, in order to verify the serviceability of the suggested dynamic situation authentication system, the medical staffs download the mobile application from the medical information server to the medical staff's own mobile device together with the dynamic situation authentication process and the permission to access medical information to the patient and showed access to medical information.