• Journal of The Korean Society of Agricultural Engineers
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• v.46 no.2
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• pp.107-114
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• 2004

NPS pollutant loads from sandy clayey and clayey loam runoff plots were measured. Runoff plots were 2$\times$10 m in size and 8~10% in slope and paddy area was 4,620 $m^2$. Soybean, corn, tobacco and control (natural weed) were cultured. Precipitation during the growing season of June to October, 2002 was 869.5 mm. Runoff and water quality were measured more than 10 times during the measurements depending on the growing stage. Pollutants loads were estimated by using respective concentration and runoff volume. Runoff occurred when daily rainfall exceeded about 30 mm. The largest runoff was observed from the paddy but pollutant loads were larger from upland crops than those from paddy. SS loads from paddy and upland were 1.4 ton/ha/yr and 3.1~4.3 ton/ha/yr, respectively. COD loads 30 kg/ha/yr and 66~90 kg/ha/yr, T-N loads 13 kg/ha/yr and 14~23 kg/ha/yr, T-P loads 1 kg/ha/yr와 4 kg/ha/yr, nitrate nitrogen loads 1 kg/ha/yr and 4~8 kg/ha/yr, and phosphate phosphorus loads 0 kg/ha/yr and 4~6 kg/ha/yr, respectively. It was concluded that NPS pollutant loads from upland crop culture have greater impact on the quality of the receiving water body than those from paddy culture.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.2
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• pp.161-166
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• 2011

In this study, design of hull and test of model boat were carried out with electric propulsion small boat driven by photo-voltaic energy. The shape of boat was made with catamaran type by considering the ship's stability, the light-receiving area from solar. According to calculation, when speed of model boat is 5 knots, it was estimated the available power for propulsion with 1.1[hp]. However, the natural energy such as solar energy is strictly dependent upon the climate conditions so the real boat speed is slightly lower than the estimated value.

• The International Journal of Costume Culture
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• v.2 no.1
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• pp.62-76
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• 1999

The objectives of this study are to investigate consumer experiences with premiums, consumer preferences in premiums offered for clothing and the effect of premiums on clothing purchasing behaviors. A self-administered questionnaire survey was conducted to 610 men and women from ages 15 to 59 living in the Seoul metropolitan area from February 25 to March 9, 1999 ; 548 were used for the data analysis. Data was analyzed by descriptive statistics, t-test, ANOVA, chi-square analysis and Duncan's multiple range tests. Significant differences were found among selected demographic groups in information sources used for premium offers, experiences of receiving premiums, purchasing experiences due to premium offers, preferences between discount and premiums, additional purchase intentions because of premiums, and the premiums'influences. The groups with purchase experiences or brand and stores selecting experiences due to premium, showed significant differences in premiums'influences and the satisfaction levels with premiums. Regarding preferences between discount and premiums, significant differences were found in and the satisfaction levels with premiums.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.5
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• pp.533-543
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• 2016

Supplying clean and safe water to people is facing both quantitative and qualitative challenges. Due to climate change, access to freshwater becomes increasingly difficult, while pollution from various sources decreases the public trust in water quality. Managed aquifer recharge (MAR) which stores and uses surface water in aquifer is receiving attention as a new technology to secure freshwater. Recently, there is a global expansion in the attempt to combine general purification plants and hazard analysis and critical control point (HACCP) which manages all the process from raw material to consumer for food safety. This research is about an attempt to apply HACCP to the drinking water supply process using MAR to secure both quantity and quality of drinking water. The study site is a MAR plant being constructed in the downstream area of the Nakdong River Basin, South Korea. The incorporation of HACCP with MAR-based water supply system is expected to enhance the safety and reliability of drinking water.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.33-34
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• 2006

Computer Forensics is a research area which finds the malicious users by collecting and analyzing the intrusion or infringement evidence of the computer crime. Many research about Computer Forensics has been done. But those research have focussed on how to collect the evidence after receiving the damage reports from computer users or network administrators. This paper describes about collecting the evidence of good quality at the time of infringement occurrence by the malicious user. By calculating Infringement severity of observable and protective hosts and referring to this value, we collect the evidence at the time of infringement occurrence to minimize the information modification of the evidence. We can reduce also the amount of logs that we use to analyze the infringement and can minimize the loss of the evidence.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.3
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• pp.430-439
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• 1999

In this paper, we have chosen Inchon International Airport as an area for estimating flutter interference to estimate and analyze the flutter Interference. We have proposed a method to overcome flutter interference. The simulation has been performed considering the received power of a direct wave, the height of an antenna, the ERP of a transmitting point, and the reflection coefficients as an estimation function for the flutter. From the simulation results, we have found that the flutter Interference from flights is very serious, and the degree of flutter interference can be changed according to the distance between an airplane and a transmitting point, the profile between transmitting and receiving points, and the reflection coefficients of an airplane.

• Journal of Communications and Networks
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• v.13 no.2
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• pp.160-166
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• 2011

In u-healthcare services based on wireless body sensor networks, reliable connection is very important as many types of information, including vital signals, are transmitted through the networks. The transmit power requirements are very stringent in the case of in-body networks for implant communication. Furthermore, the wireless link in an in-body environment has a high degree of path loss (e.g., the path loss exponent is around 6.2 for deep tissue). Because of such inherently bad settings of the communication nodes, a multi-hop network topology is preferred in order to meet the transmit power requirements and to increase the battery lifetime of sensor nodes. This will ensure that the live body of a patient receiving the healthcare service has a reduced level of specific absorption ratio (SAR) when exposed to long-lasting radiation. We propose an efficientmethod for delivering delay-intolerant data packets over multiple hops. We consider forward error correction (FEC) in an erasure correction mode and develop a mathematical formulation for packet-level scheduling of delay-intolerant FEC packets over multiple hops. The proposed method can be used as a simple guideline for applications to setting up a topology for a medical body sensor network of each individual patient, which is connected to a remote server for u-healthcare service applications.

• ETRI Journal
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• v.40 no.1
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• pp.26-38
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• 2018

To overcome considerable path loss in millimeter-wave propagation, high-gain directional beamforming is considered to be a key enabling technology for outdoor 5G mobile networks. Associated with beamforming, this paper investigates propagation power loss characteristics in two aspects. The first is beamwidth effects. Owing to the multipath receiving nature of mobile environments, it is expected that a narrower beamwidth antenna will capture fewer multipath signals, while increasing directivity gain. If we normalize the directivity gain, this narrow-beamwidth reception incurs an additional power loss compared to omnidirectional-antenna power reception. With measurement data collected in an urban area at 28 GHz and 38 GHz, we illustrate the amount of these additional propagation losses as a function of the half-power beamwidth. Secondly, we investigate power losses due to steering beam misalignment, as well as the measurement data. The results show that a small angle misalignment can cause a large power loss. Considering that most standard documents provide omnidirectional antenna path loss characteristics, these results are expected to contribute to mmWave mobile system designs.

• The Journal of Bigdata
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• v.1 no.1
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• pp.1-7
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• 2016

Social media such as twitter has been popular by the diffusion of internet, and thanks to the radical improvement of computational ability of computers big data analysis became possible. This research is regarding about smart watch which is receiving attention as post-smartphone technology. Among various types of smart watch, this research focuses on the recently released Samsung Galaxy Gear S2. The main purpose of the research is to analyze customer's actual twitter data that was produced before and after the release of the smart watch to the market. Through the analysis, this research provides practical marketing strategy guideline, and also the analysis framework used in this research can be a research framework for other area and product researches.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.16 no.1
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• pp.92-102
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• 2009

Purpose: Relocation stress is a common phenomenon in patients discharged from an intensive care unit(ICU) to a ward. Therefore, nurses need to be aware of the problems that can arise during the transfer process. The aim of this study was to identify nurses' experiences in transferring critically ill patients from the ICU to a ward. Method: Focus group interviews were done with 13 nurses from wards and ICU, which participated in receiving and sending of ICU patients. The debriefing notes and field notes were analyzed using the consistent comparative data analysis method. Result: Seven major categories were identified in the analysis of the data. These were 'mixed feeling about transfer', 'lack of transfer readiness', 'increase in family burden', 'uncertainty with unfamiliar environment', 'difficulty in decision making', 'difference of perception of the relationships between patients and health care providers', 'need for continuity of nursing care'. Conclusion: Transferring out of the critical care area should be presented to the patient and family as a positive step in the recovery process. However, a more universal method of passing information from nurse to nurse is needed to assist in a smooth transition.