• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.18 no.2
• /
• pp.303-310
• /
• 2014

We show improved throughput scaling laws for an ultra-wide band (UWB) ad hoc network, in which n wireless nodes are randomly located. First, we consider the case where a modified hierarchical cooperation (HC) strategy is used. Then, in a dense network of unit area, our result indicates that the derived throughput scaling depends on the path-loss exponent ${\alpha}$ for certain operating regimes due to the power-limited characteristics. It also turns out that the HC protocol is dominant for 2 < ${\alpha}$ < 3 while using the nearest multihop (MH) routing leads to a higher throughput for ${\alpha}{\geq}3$. Second, the impact and benefits of infrastructure support are analyzed, where m base stations (BSs) are regularly placed in UWB networks. In this case, the derived throughput scaling depends on ${\alpha}$ due to the power-limited characteristics for all operating regimes. Furthermore, it is shown that the total throughput scales linearly with parameter m as m is larger than a certain level. Hence, the use of either HC or infrastructure is helpful in improving the throughput of UWB networks in some conditions.

• Journal of Korean Society of Transportation
• /
• v.30 no.6
• /
• pp.13-26
• /
• 2012

In this study, factors influencing the parking policy compliance (i.e. levying a garage option on car buyers) were identified, and then, were applied to the theory of planned behavior. To find out the influence of factors and their path, the study built a parking policy compliance model using structural equation modeling. The independent variables such as attitude, subjective norm, perceived behavioral control had positive effects on the parameter describing the efforts to secure his garage, but the parameter impact on the dependent variable was not significant. In the end, the independent variables affected the dependent variable was not significant. The perceived behavioral control utilizing regulations had positive effects on the parking policy compliance behavior, but past behavior such as street parking and prowling to find a free parking space had a negative effect on parking policy compliance behavior.

• Journal of the Korean Society for Library and Information Science
• /
• v.49 no.4
• /
• pp.5-30
• /
• 2015

This study was conducted to raise awareness of careers in the Department of Library and Information Science (LIS) as well as to investigate current awareness and preferences for LIS Department as a strategy to cope with the rapidly changing university environment. To do this, a survey of high school students was carried out, with results as follows: First, awareness about the LIS Department and awareness about librarians in our country's high school students was very low. Second, for possible careers in LIS Department, students responded that a graduate of LIS department was likely to enter the workplace in public libraries, state libraries, university libraries, or school libraries, but they would like to work at broadcasting library, national libraries, school libraries, university libraries, public libraries, or portals. Third, awareness of the career path for the LIS Department showed a very large impact on a preference for the LIS Department. Therefore, students who have heard about the LIS Department are highly probable to select this department when they reach university.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.9 no.5
• /
• pp.131-138
• /
• 2009

In this paper, a dynamic warning system to forecast inland flooding associated with typhoons and storms is described. The system is used operationally during the typhoon season to anticipate the potential impact such as inland flooding on the coastal zone of interest. The system has been developed for the use of the public and emergency management officials. Simple typhoon models for quick prediction of wind fields are implemented in a user-friendly way by using a Graphical User Interface (GUI) of MATLAB. The main program for simulating tides, depth-averaged tidal currents, wind-driven surges and currents was also vectorized for the fast performance by MATLAB. By pushing buttons and clicking the typhoon paths, the user is able to obtain real-time water level fluctuation of specific points and the flooding zone. This system would guide local officials to make systematic use of threat information possible. However, the model results are sensitive to typhoon path, and it is yet difficult to provide accurate information to local emergency managers.

• The Journal of Industrial Distribution & Business
• /
• v.10 no.4
• /
• pp.67-76
• /
• 2019

Purpose - This study attempted to construct and validate a structural model of the relationship between the quality of medical services, perceived risk, reputation and customer satisfaction, which is the main concept of the relationship between large hospitals as well as small and medium hospitals and medical consumers. Through this verification, the small and medium hospitals are to find the way for wise coping in competitive situation with large hospitals. Research design, data, and methodology - This research developed a hypothesis by constructing a structural equation that reaches the satisfaction and the relationship between reputation of perceived risk and perceived risk of service quality perceptions of customers of small and medium hospitals. Research data were collected through a questionnaire survey of respondents who had medical service experience from small and medium hospital. A total data of 252 respondents were used as the sample for the final analysis and analyzed using SPSS 23.0 and AMOS 23. Results - As a result, the relationship of quality of medical service, reputation, and customer satisfaction among small and medium hospitals was consistent with the results of precedent studies, and the perceived risk has a significant impact on reputation, so the greater the perceived risk, the higher the preference for reputable medical institutions as large hospitals. In addition, it was found that the direct route from perceived risk to customer satisfaction was not significant, and reputation was found to have a full mediating effect on perceived risk and customer satisfaction. Customers who use small and medium hospitals prefer to use reputable medical institutions if their perceived risk is high, which is different from risk perception when specific targets are specified. Conclusions - In terms of the effect from customer satisfaction, not only the path of perceived risk → reputation → customer satisfaction, but also the quality of service quality → reputation → customer satisfaction. These findings suggest that small and medium hospitals are appropriately responding to competition with large hospitals, rather than focusing on the perceived risks and reputation of customers in establishing and utilizing competitive strategies to create new customers and preserve existing customers.

• Journal of Distribution Science
• /
• v.17 no.1
• /
• pp.73-87
• /
• 2019

Purpose - This research aims to investigate the effects that the selection of oriental medicine cosmetics and brand asset attributes have on consumers' economic, emotional and social values in order to shed light on the forms and characteristics of consumption within the globally developing oriental medicine cosmetics market, and in the end positively verify how such perceived values affect purchase intention. In addition, it proposes research outcomes by comparing the differences between national and cultural consumer purchase behavior based on the comparisons of consumer groups in South Korea and China, the major markets for oriental medicine cosmetics. Research design, data, and methodology - Based on advanced research a total of 9 hypotheses were designed and questionnaires consisting of 16 questions to identify six major variables were conducted. Research was carried out centered on Seoul, South Korea, and its surrounding metropolitan area as well as Beijing and Shanghai, China, and a total of 577 sets of significant data were collected. A comparison analysis was then conducted on the data from 285 Koreans and 292 Chinese. A regression analysis and path analysis were also carried out based on a structural equation model to suggest results. Results - Research results show brand value assets had a more crucial impact on consumers' perceived value than consumer selection of oriental medicine cosmetics, while emotional value had a bigger effect on purchase intension than social or economic values. For Chinese consumers in particular, social, economic and emotional values affected purchase intention, while emotional value was the most crucial factor for Korean consumers. Conclusions - With oriental medicine cosmetics, brand characteristics and images that helped express emotional desire proved to be more effective in marketing than the performance aspect of cosmetics, including their functions and ingredients. In the end, products that highlight individual desire and emotion should be introduced instead of those that emphasize price, functions and social characteristics in order to expand the global market of oriental medicine cosmetics.

• The KIPS Transactions:PartD
• /
• v.16D no.1
• /
• pp.43-54
• /
• 2009

The purpose of this study is to explore variables that affect users' perceived value of mobile advertising and actual response intention and to analyze causal relationships among variables. In order to verify the relational significance, we built new research model and hypotheses based on the Ducoffe's model(1996). And we found out four independent variables such as entertainment, information usefulness, convenience, economical efficiency, and advertising impact's value as a mediating variable. Especially, we classified into four multi-age groups to investigate properly moderating effects through SEM(path analysis) and difference test. Therefore, it is academical and practical worth that we developed our model to appropriate on mobile advertising's unique property and that we verified our hypotheses and variables focused on age group, whereas previous research did not. For this, we surveyed 345 samples for conducting structural equation modeling in empirical approach. The results of this study supported the statistical significance of all hypotheses except but convenience.

• Korean Journal of Remote Sensing
• /
• v.22 no.5
• /
• pp.313-323
• /
• 2006

Forest Canopy Density is a dynamic process mediated by various natural and anthropogenic factors. It can be changed over time and locations in the same forest type and landscape. However, human dimensions are considered as the primary force of landscape change and subsequent forest canopy loss in tropical regions of the world. Many studies have been indicated that roads have a far greater impact on forests than simply allowing access for human use. Similarly, rivers have been used as means of transportation, hence illegal logging and felling further deplete forest canopy density. The main objective of this study was to investigate the spatio-temporal dynamic alterations of Forest Canopy Density (FCD) across with site associated factors such as biophysical, physical and human interferences in tropical region of Nepal from 1988 to 2001. Landsat TM and ETM+ of 1988 and 2001 were used to assess the spatial and temporal dynamic alterations of FCD. This analysis revealed that distance to human settlements at P=<0.01, rivers, human interferences (path and fire) and species composition had a statistically significance at P=<0.05 level. However, other factors did not show any significant relation. So, we concluded that understanding of dynamic alterations of FCD with respect to factors was quite complex phenomena. Other surrounding environment could also playa significant role. A comprehensive analysis could be required to understand such complexities. Therefore, additional factors such as climatic, biophysical, social, and institutional with respect to spatio-temporal variability should be considered for the better understanding of canopy dynamic.

• Journal of the Korean Solar Energy Society
• /
• v.36 no.1
• /
• pp.11-18
• /
• 2016

The local wind systems in the Pohang region were categorized into wind sectors. Still, thorough knowledge of wind resource assessment, wind environment analysis, and atmospheric environmental impact assessment was required since the region has outstanding wind resources, it is located on the path of typhoon, and it has large-scale atmospheric pollution sources. To overcome the resolution limitation of meteorological dataset and problems of categorization criteria of the preceding studies, the high-resolution wind resource map of the Korea Institute of Energy Research was used as time-series meteorological data; the 2-step method of determining the clustering coefficient through hierarchical clustering analysis and subsequently categorizing the wind sectors through non-hierarchical K-means clustering analysis was adopted. The similarity of normalized time-series wind vector was proposed as the Euclidean distance. The meteor-statistical characteristics of the mean vector wind distribution and meteorological variables of each wind sector were compared. The comparison confirmed significant differences among wind sectors according to the terrain elevation, mean wind speed, Weibull shape parameter, etc.

• Safety and Health at Work
• /
• v.7 no.2
• /
• pp.124-129
• /
• 2016

Background: Work-related fatigue has a strong impact on performance and safety but so far, no agreed upon method exists to detect and quantify it. It has been suggested that work-related fatigue cannot be quantified with just one test alone, possibly because fatigue is not a uniform construct. The purpose of this study is therefore to measure work-related fatigue with multiple tests and then to determine the underlying factorial structure. Methods: Twenty-eight employees (mean: 36.11; standard deviation 13.17) participated in five common fatigue tests, namely, posturography, heart rate variability, distributed attention, simple reaction time, and subjective fatigue before and after work. To evaluate changes from morning to afternoon, t tests were conducted. For further data analysis, the differences between afternoon and morning scores for each outcome measure and participant (${\Delta}$ scores) were submitted to factor analysis with varimax rotation and each factor with the highest-loading outcome measure was selected. The ${\Delta}$ scores from tests with single and multiple outcome measures were submitted for a further factor analysis with varimax rotation. Results: The statistical analysis of the multiple tests determine a factorial structure with three factors: The first factor is best represented by center of pressure (COP) path length, COP confidence area, and simple reaction time. The second factor is associated with root mean square of successive difference and useful field of view (UFOV). The third factor is represented by the single ${\Delta}$ score of subjective fatigue. Conclusion: Work-related fatigue is a multidimensional phenomenon that should be assessed by multiple tests. Based on data structure and practicability, we recommend carrying out further studies to assess work-related fatigue with manual reaction time and UFOV Subtest 2.