• Journal of Astronomy and Space Sciences
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• v.41 no.1
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• pp.25-33
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• 2024

This paper evaluates the influence of rainfall on propagated signal at different time exceedance percentages of an average year, over the climate zones of the country. Specifically, it demonstrates critical and non critical signal fade or signal outage time exceedance (0.001% to 1%) for Ku, K, and Ka-band systems in an average year. The study was carried out using meteorological data made available by the Nigerian Meteorological Agency (NiMet) over a period of 10 years (2009-2018). The four climate zones in the country were represented by five (5) locations; Maidugiri (warm desert climate), Sokoto (tropical dry climate), Port Harcourt (tropical monsoon climate), Abuja and Enugu (tropical savanna climate). The parameters were simulated into the International Telecommunications Union Recommended (ITU-R) models for rain attenuation over the tropics and results presented using MatLab and Origin Lab. Results of Ku band propagations showed that only locations in the tropical savanna and tropical monsoon climates experienced total signal outage for time percentage exceedance equal to or below 0.01% for both horizontal and vertical polarizations. At K band propagations, the five locations showed to have experienced signal outage at time exceedance equal to and below 0.01%, almost same was recorded for the Ka-band propagation. It was also observed that horizontal and vertical polarization of signal had slightly different rain attenuation values for the studied bands at the five locations, with horizontal polarization having higher values than vertical polarization.

• Journal of Korea Water Resources Association
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• v.47 no.4
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• pp.371-384
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• 2014

This study developed a new algorithm of extreme rainfall extraction based on the Communication, Ocean and Meteorological Satellite (COMS) and the Tropical Rainfall Measurement Mission (TRMM) Satellite image data and evaluated its applicability for the heavy rainfall event in July-2011 in Seoul, South Korea. The power-series-regression-based Z-R relationship was employed for taking into account for empirical relationships between TRMM/PR, TRMM/VIRS, COMS, and Automatic Weather System(AWS) at each elevation. The estimated Z-R relationship ($Z=303R^{0.72}$) agreed well with observation from AWS (correlation coefficient=0.57). The estimated 10-minute rainfall intensities from the COMS satellite using the Z-R relationship generated underestimated rainfall intensities. For a small rainfall event the Z-R relationship tended to overestimated rainfall intensities. However, the overall patterns of estimated rainfall were very comparable with the observed data. The correlation coefficients and the Root Mean Square Error (RMSE) of 10-minute rainfall series from COMS and AWS gave 0.517, and 3.146, respectively. In addition, the averaged error value of the spatial correlation matrix ranged from -0.530 to -0.228, indicating negative correlation. To reduce the error by extreme rainfall estimation using satellite datasets it is required to take into more extreme factors and improve the algorithm through further study. This study showed the potential utility of multi-geostationary satellite data for building up sub-daily rainfall and establishing the real-time flood alert system in ungauged watersheds.

• Journal of Korean Academy of Nursing Administration
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• v.18 no.1
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• pp.13-22
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• 2012

Purpose: This study was done to analyze the relationship between organizational communication satisfaction and organizational commitment among hospital nurses. Method: A survey was conducted with 647 nurses who were working in 24 hospitals in Korea. Data were collected during August 2010. Data were analyzed using descriptive statistics, t-test, ANOVA, Pearson correlation analysis, and multiple regression. Results: The mean level of organizational communication satisfaction was 3.15 (min 1.88 -max 4.88) and the mean level of organizational commitment was 3.21 (min 1.33 - max 4.83). There was a statistically significant correlation between organizational communication satisfaction and organizational commitment (r=. 655). According to analysis of the impact of the subconstructions of organizational communication satisfaction on organizational commitment, the following factors had significant influence on organizational communication satisfaction: vertical communication, communication media, and organizational climate. Conclusion: These findings showed that communication satisfaction was the most important factor for nurses' organizational commitment. Therefore, there is a need to develop communication strategies and skills for hospital nurses to increase the level of communication satisfaction.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1998.05a
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• pp.177-186
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• 1998

In this paper, due to the congestion the radio spectrum, frequency bands are shared among the satellite communication system. Therefore for satisfactory we have to design and predict with reasonable accuracy the level of interference that might exist among them, Interference among the satellite communication systems depends on many factors such as climate, radio frequency, time percentage of interest, distance and path topography, propagation delay time. This paper suggest design method of Low-Orbit satellite communication and calculates the field-of view of satellite, for the communication era using LEO. In addition, performs performance evaluation on the basis of link margine.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.6
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• pp.147-152
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• 2008

The Climate Change Convention has a purpose for stabilizing the concentration of greenhouse gases of the atmosphere so that the dangerous and artificial effects may not influence atmosphere systems. We intend to present the model needed to establish the systems able to monitor and control in real time not sticking to places by grafting IPTV technique and setting the monitoring objects of the greenhouse emitting sources of industrial facilities, the estimation instruction of emissions, the guidelines of emission estimation, etc. in order to corresponding to this Climate Change Convention.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.1
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• pp.223-228
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• 2015

Korean climate becoming increasingly subtropical by climate warming makes local heavy rainfall frequently. To avoid damages from the local heavy rainfall, we need a forecasting service for a great number of clients. However, there is not the framework for the service based on wireless data broadcasting yet. In this paper, we design and implement a service framework for local heavy rainfall forecasting using wireless data broadcast. The developed service framework has scalability that can adopt various data scheduling and indexing schemes. We show the efficiency of the proposed framework to forecast local heavy rainfall through a simulation study.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.4
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• pp.813-818
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• 2018

In this paper, the assessment items were selected for water by drought, water quality by drought, and thermal diseases by heat wave. We described the selection background for these assessment items. and then we weighted the selected vulnerability assessment items. The vulnerability assessment procedures also describe the calculation methods applied in phases and the actual cases. The vulnerability assessment database was analyzed and a climate change vulnerability assessment system for heat waves and droughts using these vulnerability assessment procedures was designed.

• Korean Journal of Occupational Health Nursing
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• v.31 no.2
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• pp.66-76
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• 2022

Purpose: This study aimed to explore the constructs and context of hospital nurses' organizational silence. Methods: In-depth interviews were conducted with 17 nurses in small-middle general hospitals as well as big university hospitals. We then derived the key themes using grounded theory method. Results: Nine themes and 30 sub-themes were derived: "Willing to be recognized for performance rather than saying", "Getting used to the hard-to-speak climate", "Face the reality that does not change when said", "Complicated situation that prevents self-regulating decision-making", "Conflicts that are difficult to confront", "Unfair responsibilities that I want to evade", "Leaders who don't support me", and "Being blocked in communication". Consequently, the nurses learned to adopt a climate of silence and "learned organizational silence" behavior. They experienced that prosocial silence was essential for obtaining approval as a member of the group, and defensive silence for protecting themselves in the hierarchical structure and unfair responsibilities. Acquiescent silence originated from a futile relationship with their supervisors, one-way communications, and the unsupportive management system, in which three types of silence appeared sequentially or in combination with each other. Conclusion: Based on these results, nursing managers should identify the context of nurses' organizational silence and should lessen these silence behaviors.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.3
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• pp.325-330
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• 2016

Sea level is upward trend since the end of 19th century, it is accelerating after 20th century. Because sea level height has regional differences, we concerned sea level change in Korean Peninsula. We used Topex/Poseidon, Jason-1 and Jason-2 satellite altimetry data which has $1/4^{\circ}$ resolution. From 1993 to 2013, for 21 years, monthly mean sea level anomaly was negative between January and April, positive between March and October. Bohai Bay in China, affected the continental climate, showed big sea level changes. Mean sea level data showed remarkably affecting the continental climate in Bohai Bay in China, the Kuroshio Current and eddy affects the sea level change.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.3
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• pp.189-197
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• 2022

With the development of high-performance computing technology and the advancement of numerical model, it is possible to predict the better weather forecasting. The purpose of this paper is the performance improvement for the SCAM climate model for the model running time excluding the compilation time. Therefore, the model previously performed using the Intel Fortran Compiler was changed to PGI Fortran Compiler. To this end, we reconfigure system environment variables, reset compilation options, install dependencies SW and library, and modify source code. In addition, we proposed and applied the 'PGI Compile with OpenACC' method. As a result, when the compiler was changed from intel to PGI, it led to an improvement of 6.08% in running time and when the openACC method was applied, it led to an improvement of 43.05% in running time. This demonstrates that the PGI Compile with OpenACC method proposed in this paper leads to excellent performance.