• Atmosphere
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• v.30 no.2
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• pp.169-181
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• 2020

We conducted a study on the impact of observation station density; this was done in order to enable the accurate estimation of spatial meteorological variables. The purpose of this study is to help operate an efficient observation network by examining distributions of temperature, relative humidity, and wind speed in a test area of a three-dimensional meteorological observation project in the Yeongdong region in 2019. For our analysis, we grouped the observation stations as follows: 41 stations (for Step 4), 34 stations (for Step 3), 17 stations (for Step 2), and 10 stations (for Step 1). Grid values were interpolated using the kriging method. We compared the spatial accuracy of the estimated meteorological grid by using station density. The effect of increased observation network density varied and was dependent on meteorological variables and weather conditions. The temperature is sufficient for the current weather observation network (featuring an average distance about 9.30 km between stations), and the relative humidity is sufficient when the average distance between stations is about 5.04 km. However, it is recommended that all observation networks, with an average distance of approximately 4.59 km between stations, be utilized for monitoring wind speed. In addition, this also enables the operation of an effective observation network through the classification of outliers.

• Tunnel and Underground Space
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• v.6 no.1
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• pp.30-38
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• 1996

A two dimensional analysis program for groundwater flow in fractured network was developed to analyze the influence of discontinuity characteristics on groundwater flow. This program involves the generation of discontinuities and also connectivity analysis. The discontinuities were generated by the probabilistic density function(P.D.F.) reflecting the characteristics of discontinuities. And the fracture network model was completed through the connectivity analysis. This program also involves the analysis of groundwater flow through the discontinuity network. The result of numerical experiment shows that the equivalent hydraulic conductivity increased and became closer to isotropic as the density and trace length increased. And hydraulic head decreased along the fracture zone because of much water-flow. The grouting increased the groundwater head around cavern. An analysis of groundwater flow through discontinuity network was performed around underground oil storage cavern which is now under construction. The probabilistic density functions(P.D.F) were obtained from the investigation of the discontinuity trace map. When the anisotropic hydraulic conductivity is used, the flow rate into the cavern was below the acceptable value to maintain the hydraulic containment. But when the isotropic hydraulic conductivity is used, the flow rate was above the acceptable value.

• Korean Journal of Health Education and Promotion
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• v.33 no.3
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• pp.1-11
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• 2016

Objectives: The challenging issue of public health program is to strengthen partnership and network between health resources. This study identified the structure and characteristics of school health program network. Methods: In this paper we collected data from schools and organizations in 4 local communities in 2014 that participated to school health program. Using social network analysis techniques we measured the number of component, diameter, density, average degree, node centralization for each network. Results: We determined that networks shared some common organizational structure such as less density, low average degree, and short diameter. Networks were dominated by the health center, and directions of collaborations between nodes were mostly one-way. Conclusions: These findings can help to depict the network of school health program. The further research is necessary to define causal relationship between network effectiveness and public health outcomes.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.181-183
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• 2005

Network Reprogramming 에서는 코드 전파가 완료되기까지 걸리는 시간과 에너지 소모가 문제가 된다. 지금까지의 연구들은 에너지 소모를 줄이기 위해서 완료시간을 줄이는 방법에 초점을 두었지만 제한된 에너지를 사용해야 하는 센서 네트워크에서는 전송된 메시지에 의한 에너지 소모도 고려해야 한다. 본 논문에서는 코드 전파 시 전송 메시지 개수를 최소로 하는 DANP를 제시한다. DANP는 각 노드가 이웃 노드에 대한 정보를 이용하여 advertisement 주기를 적절히 늘려서 모든 경우의 Density에 대해서 코드 전파의 효율성을 높인다.

• Knowledge Management Research
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• v.13 no.4
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• pp.71-82
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• 2012

The purpose of this study is to investigate the effects of employees who attend graduate school on the expansion of the knowledge sharing network in their company. For this purpose, the researchers chose 10 worker-graduate students and 75 members of company 'A' that they belong to and 107 members of university 'B' that they belong to, 172 members in total. 10 overlapped employee-students were excluded. The results of this study are summarized as follow: First, the personal relations of the employee-students enhanced after they have entered the graduate school. The score for the question was 3.85 out of 5 points. Second, the employee-students played the role of the knowledge bridge between company's co-worker network and graduate school's classmate network. It was confirmed that the density of the company's network was higher than the density of the connected network of the company and the graduate school. The analysis result confirmed that the difference of the two groups was significant. This means that the company carried out exchange with more members and therefore gained various kinds of knowledge. Also, in all types of network, the structural hole of the company network was lower than that of the connected network of the company and graduate school. The ANOVA test using QAP procedure confirmed that the difference of two groups was significant (friendship network F=1.2856, p<0.05; information network F=1.278, p<0.05; and trust network F=1.23, p<0.05). It means that the company not only gained the newly acquired knowledge by the knowledge bridge of the employee-students, but also was able to share it more effectively with members. Third and lastly, the employee-students share various information related to the organization, duties and roles rest in the company throughout break time, working hours and direct inquiries. This means that the employee-students contributed to the innovation of knowledge sharing in the company by sharing knowledge that they gained from the graduate school within the company.

• Korean journal of communication and information
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• v.33
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• pp.53-86
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• 2006

This paper presents comparative analysis of the traits of personal network structure shaping in local press organizations of Korea. For this analysis, this study attempts to investigate three topics. First, the density traits of personal network structure in the whole of local press organization. Second, the comparison of density trait shaping in personal network structure between press section of local broadcasting stations and local newspaper companies. Third, the positional trait in each local press organization. To answer the questions, the data concerning commissioners and executive members in local daily newspapers and local broadcasting organizations from the Civic Government to the People's Government have been collected and analyzed. The interconnections of regional(birthplace) and educational(university graduated) aspect were analyzed via methods of cross analysis, density analysis and correspondence analysis. In brief, major findings of this study are as follows ; As a result of analyzing cross analysis and density analysis of the personal network based of regional and educational aspect, the numerical value of density was too high on the whole of local press organizations. But, especially local newspaper companies has been showed that was higher density compared with press section of local broadcasting stations. And, positional distance between local press organizations were showed obviously in the case of regional(birthplace) aspect. But, in case of educational aspect, positional distance were showed obviously between commissioners and executive members.

• Atmosphere
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• v.29 no.2
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• pp.183-196
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• 2019

High-quality and high-resolution meteorological information is essential to reduce damages due to disastrous weather phenomena such as flash flood, strong wind, and heat/cold waves. There are many meteorological observation stations operated by Korea Meteorological Administration (KMA) in Seoul Metropolitan Area (SMA). Nonetheless, they are still not enough to represent small-scale weather phenomena like convective storm cells due to its poor resolution, especially over urban areas with high-rise buildings and complex land use. In this study, feasibilities to use additional pre-existing networks (e.g., operated by local government and private company) are tested by investigating the effects of network density on the gridded horizontal distribution of two meteorological variables (temperature and precipitation). Two heat wave event days and two precipitation events are chosen, respectively. And the automatic weather station (AWS) networks operated by KMA, local-government, and SKTechX in Incheon area are used. It is found that as network density increases, correlation coefficients between the interpolated values with a horizontal resolution of 350 m and observed data also become large. The range of correlation coefficients with respect to the network density shows large in nighttime rather than in daytime for temperature. While, the range does not depend on the time of day, but on the precipitation type and horizontal distribution of convection cells. This study suggests that temperature and precipitation sensors should be added at points with large horizontal inhomogeneity of land use or topography to represent the horizontal features with a resolution higher than 350 m.

• Journal of Korea Multimedia Society
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• v.13 no.6
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• pp.911-923
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• 2010

In wireless sensor networks (WSNs), cluster based data routing protocols have the advantages of reducing energy consumption and link maintenance cost. Unfortunately, most of clustering protocols have been designed for uniformly distributed sensor networks. However, some urgent situations do not allow thousands of sensor nodes being deployed uniformly. For example, air vehicles or balloons may take the responsibility for deploying sensor nodes hence leading a normally distributed topology. In order to improve energy efficiency in such sensor networks, in this paper, we propose a new cluster formation algorithm named DAEEC (Density Aware Energy-Efficient Clustering). In this algorithm, we define two kinds of clusters: Low Density (LD) clusters and High Density (HD) clusters. They are determined by the number of nodes participated in one cluster. During the data routing period, the HD clusters help the neighbor LD clusters to forward the sensed data to the central base station. Thus, DAEEC can distribute the energy dissipation evenly among all sensor nodes by considering the deployment density to improve network lifetime and average energy savings. Moreover, because the HD clusters are densely deployed they can work in a manner of our former algorithm EEVAR (Energy Efficient Variable Area Routing Protocol) to save energy. According to the performance analysis result, DAEEC outperforms the conventional data routing schemes in terms of energy consumption and network lifetime.

• International journal of advanced smart convergence
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• v.12 no.4
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• pp.147-153
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• 2023

In recent times, an absence of effective crowd management has led to numerous stampede incidents in crowded places. A crucial component for enhancing on-site crowd management effectiveness is the utilization of crowd counting technology. Current approaches to analyzing congested scenes have evolved beyond simple crowd counting, which outputs the number of people in the targeted image to a density map. This development aligns with the demands of real-life applications, as the same number of people can exhibit vastly different crowd distributions. Therefore, solely counting the number of crowds is no longer sufficient. CSRNet stands out as one representative method within this advanced category of approaches. In this paper, we propose a crowd counting network which is adaptive to the change in the density of people in the scene, addressing the performance degradation issue observed in the existing CSRNet(Congested Scene Recognition Network) when there are changes in density. To overcome the weakness of the CSRNet, we introduce a system that takes input from the image's information and adjusts the output of CSRNet based on the features extracted from the image. This aims to improve the algorithm's adaptability to changes in density, supplementing the shortcomings identified in the original CSRNet.

• The Journal of the Korea Contents Association
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• v.14 no.9
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• pp.582-588
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• 2014

The purpose of this study is to analyze how a joint research network between countries affects the diffusion of technology information and how much countries with high centrality on the network accept new technology and to seek their meaning. With this aim, the joint research network density between countries by year and the number of participating countries were measured using thesis information regarding the secondary battery field and the electric vehicle field, and a regression analysis of relevant variables was conducted. As a result of the analysis, the greater the joint research network density in the secondary battery field, the higher the number of participating countries in a linear relationship. Also, on the joint research network, countries with high degree centrality were discovered to have led development in the mid to large size secondary battery field. Meanwhile, for the electric vehicle field, although there appeared no increase in the network density value, the number of participating countries was found to have increased. This was analyzed that joint research between countries was not a necessary and sufficient condition although it played a crucial role in promoting technology diffusion. Such a result is meaningful in that it verified promoting factors for essential technology diffusion statistically; however, with this research, there exist limitations that the index of a central role on the network was measured only with degree centrality and that only the relationship between two players was measured for network density in interactions between players. Accordingly, it is necessary to carry out research into a method to measure interactions among multiple researchers in the future.