• 대기
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• 제30권2호
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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.

• 터널과지하공간
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• 제6권1호
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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.

• 보건교육건강증진학회지
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• 제33권3호
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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.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2005년도 가을 학술발표논문집 Vol.32 No.2 (1)
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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.

• 지식경영연구
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• 제13권4호
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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.

• 한국언론정보학보
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• 제33권
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• pp.53-86
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• 2006

본 연구는 지역 언론에 내재한 연고 네트워크 구조를 밀도와 지형상의 특성을 분석함으로써 지역 언론에 내재한 연고 네트워크 구조의 지역별 비교 분석을 그 목적으로 한다. 연구 목적을 달성하기 위해 설정한 연구문제는 첫째, 지역 언론사들에 내재한 연고에 따른 밀도 특성, 둘째, 지역 방송사 내의 언론조직과 신문사 조직 간의 연고에 입각한 밀도 비교, 세 번째, 지역 언론사 조직 구성원들의 연고에 따른 지형적 특성이다. 본 연구를 수행하기 위해 문민정부와 국민정부 시기에 지역의 광역시에 소재하고 있는 주요 일간지와 지역 방송사의 뉴스 조직을 분석 대상으로 설정하였으며, 밀도 분석과 교차 분석, 그리고 대응 분석 방법을 병행하여 활용하였다. 분석 결과, 각 지역에 소재하고 있는 언론사 내부 조직 구성원의 집중 경향을 교차분석과 밀도분석을 통해 살펴본 결과, 해당 신문사의 지역적 기반과 근접한 지역 출신 인사들을 중심으로 신문사와 방송사 공히 조밀한 구조를 보이고 있으나, 특히, 신문사가 방송사 내부의 뉴스 조직에 비해 집중 경향이 더욱 높은 것으로 분석되었다. 아울러, 대응 분석을 통해 지역 언론사의 위치상의 특성을 분석한 결과, 출신 지역에 있어서는 직위에 관계없이 위치상의 차이가 명확하게 나타나고 있으며, 출신 대학의 경우 이사진과 실무진 간의 위치적 차이가 드러나고 있다는 점이 특징적이다.

• 대기
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• 제29권2호
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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.

• 한국멀티미디어학회논문지
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• 제13권6호
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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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• 제12권4호
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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.

• 한국콘텐츠학회논문지
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• 제14권9호
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• pp.582-588
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• 2014

본 연구는 국가간 공동연구 네트워크가 기술 지식의 확산에 어떠한 영향을 미치는 가와 네트워크 상에서 중심성이 높은 국가가 새로운 기술을 얼마나 받아들이는지 분석하고 그 의미를 찾는 것을 목적으로 한다. 이를 위해 이차전지 분야와 전기 자동차 분야 논문 정보를 이용하여 연도별 국가간 공동연구 네트워크 밀도와 참여국가 수를 측정하고 변수간의 회귀분석을 수행하였다. 분석결과, 이차전지 분야 공동연구 네트워크 밀도가 증가할수록 참여국가 수는 선형관계로 증가하는 것으로 나타났다. 또한 공동연구 네트워크 상에서 연결정도 중심성이 높은 국가들이 중대형 이차전지 분야 개발을 주도하고 있는 것으로 나타났다. 반면에 전기 자동차 분야의 경우, 네트워크 밀도값은 증가 추세가 나타나지 않지만, 참여국가 수는 증가하고 있는 것으로 나타났다. 이는 기술 확산을 촉진하는데 있어서, 국가간 공동연구가 중요한 역할을 하지만 필요충분 조건은 아닌 것으로 분석되었다. 이러한 결과는 기술 성장에 있어서 반드시 필요한 기술 확산을 촉진하는 요인을 통계적으로 검증하였다는 점에서 의의가 있으나, 네트워크 상에서 중심적 역할에 대한 지표를 연결정도 중심성 만으로 측정하였다는 점과 네트워크 밀도가 행위자간 상호작용에 있어서 반드시 두 행위자간 관계만을 측정한다는 점에서 연구의 한계가 존재한다. 따라서 향후 다수의 연구자간 상호작용을 측정할 수 있는 방안에 대한 연구가 필요하다.