• Journal of Korean Society of Environmental Engineers
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• v.38 no.10
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• pp.580-587
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• 2016

This study aims to estimate the values of freshwater ecosystem services from demand and supply perspectives. From demand side, unit-values of ecosystem services are derived from Environmental Valuation Information System (EVIS) and aggregated to 5 main watersheds in Korea. The derived unit-values are based on the willingness to pay estimates per household from stated preference methods. The nation-wide average total values of water quantity supply, water purification, and natural disaster control are estimated as 501.2, 410.4, and 242.4 billion won/year, respectively. From supply side, we examine the direct and indirect public expenditures (or investment) in 2013 to improve freshwater ecosystem services by the government. The total sum of government expenditures corresponds to 8,882 billion won in 2013, where 12.9, 81.3, 0.3 and 5.3% are spent to improve provisioning, regulating, supporting and cultural services, respectively, indicating that most efforts are concentrated in enhancing regulating services.

• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.1
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• pp.73-83
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• 2007

Network modeling of irrigation system that links irrigation facilities with stream is necessary to establish complicated rural water management system and to manage agricultural water effectively. This study attempted a network modeling for an agricultural water district called "ANGO" located in Anseongcheon watershed by connecting ArcHydro Model developed to control geographical information data in the field of water resources and AWDS(Agricultural Water Demand & Supply Estimation System) developed by KRC (Korea Rural Community & Agriculture Corporation). Network modeling was embodied by build topology between spatial objects of total 70 agricultural irrigation facilities (24 reservoirs, 18 pumping stations, 28 weirs) and stream network using ArcHydro Model. In addition, new menus were added in ArcGIS system for query and visualization of text-based AWDS outputs such as irrigation facilities information, water demand and supply analysis.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.1
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• pp.180-186
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• 2017

In this paper we propose a traffic aware Demand Wakeup MAC(TADW-MAC) protocol, in which low data delay and high throughput can be achieved, for wireless sensor networks. With the TADW-MAC protocol, the problem of the DW-MAC protocol, which schedules only one packet to deliver during the Sleep period in a multi-hop transmission is resolved. DW-MAC is not adequate for the applications such as object tracking and fire detection, in which busty data should be transmitted in a limited time when an event occurs [6-8]. When an event occurs, duty cycle can be adjusted in the TADW-MAC protocol to get less energy consumption and low latency. The duty cycle mechanism has been widely used to save energy consumption of sensor node due to idle listening in wireless sensor networks. But additional delay in packet transmission may be increased in the mechanism. Our simulation results show that TADW-MAC outperforms RMAC and DW-MAC in terms of energy efficiency while achieving low latency.

• Journal of Home Health Care Nursing
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• v.10 no.2
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• pp.148-157
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• 2003

The purpose of this study was to provide the basic data for developing a program for effective intervention for home health care need of postpartum mothers and newborn babies. The subjects were 104 women. The data were collected from march, 2003 to June, using a 81 item questionnaire and analyzed by SPSS program for frequency, Mean, ANOVA. The results were as follow. 1. The mean of care needs of newborn babies was higher than that of physical demand of Postpartum mothers. The mean of physical demand of Postpartum mothers was $3.99\pm.42$. The mean of care needs of newborn babies was $4.11\pm.50$. 2. The most highest mean of physical demand of Postpartum mothers was wound care for caesarean section and episiotomy($4.53\pm.66$), and then breast engorgement care($4.38\pm.71$). The most highest mean of care needs of newborn babies was emergency care methods($4.58\pm.52$), and then infection control $4.51\pm.56$). 3. 66.3% of postpartum mothers positively desired consultation hospitals centered home care need during postpartial periods. 4. Influential variables of home health care need was postpartial periods. they wanted the first week after delivery, more freqently visiting of home care nurse. 37.5% of postpatial mothers wanted visiting within 1 weeks after delivery. 31.7% wanted 2 times/week. In conclusion, it is necessary to study to make a program in nursing of home health care for postpartum mothers, and to keep on studying repeatedly in order to raise the number of objects and to find related variables.

• Journal of Technologic Dentistry
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• v.34 no.4
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• pp.403-412
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• 2012

Purpose: This study is conducted to evaluate the job stressors for dental technicians in Ulsan city. Methods: The Korean standard job stressors assessment tool developed by Korea Occupational Safety and Health Agency (KOSHA) was used to compare the survey result with Korean reference value. The questionnaire on the social, demographic and job characteristics of dental technicians was also used to find the factors affecting to job stressors by using multiple linear regression analysis. Results: A total of 155 questionnaire was collected from 2010 to 2011. Among the eight fields of stressors, the physical environment (men 50.0, women; 58.3) and job demands (men 57.1, women 57.1) were higher than the median value of the Korean Workers. By multiple linear regression analysis, the significant factors to the physical environment were the satisfaction degree of indoor odor, number of employee, duty and working hours. In terms of the job demand, duty, working hours, age, and the satisfaction to the efficiency of space utilization were significantly associated to the score of job demand. Conclusion: Based on these results, it is necessary to manage appropriate workload, control indoor odor and design an efficient work space for prevention of job stress of dental technicians.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.2 s.245
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• pp.202-209
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• 2006

As the economic power is improved and the customer's demand is hard to please, the noise and vibration is the most important yardstick that can determine the quality of the product. Especially, as the airconditioner's demand increase suddenly, the product of quality and the noise is becoming a decisive factor of determining whether purchase the product or not. Therefore, every manufactory is investing a lot of money and research to cut down the unpleasantness induced from noise and vibration. And they are emphasizing their product's difference by advertising a silence very actively. With these reason, the demand of a silent indoor air-conditioner is the essential research filed when the product is develop(:d. In this study, the noise and vibration is visualized in the space and frequency domain by using experimental methods such as operational deflection shape (ODS), modal testing and sound intensity. Also the location of noise source and its characteristic is analyzed in an acoustical point of view to reduce the structure borne noise that come from the fan motor, and the pertinent control method is suggested. Furthermore, the most suitable shape of the motor bracket is suggested by applying FEM and DOE (Design of experiments) in the noise and vibration point a view.

• Journal of the Korean Wood Science and Technology
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• v.28 no.3
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• pp.9-13
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• 2000

Wood demand is increasing more and more, but world has been confronted with decreasing forest resources. Korea has to depend upon foreign wood and wood-based products for more than 95 percent of total domestic demand per year. In order to heighten self-sufficiency for wood supply and demand, we have to develop wood substitutes. Rice hull is the cheapest agricultural by-product we can get in Korea, more over the production of rice hull amounts to 1 million tons per year. This study was carried out to utilize rice hull and to decide the optimum condition of rice hull pretreatment for manufacture of rice hull board. Steam explosion method gave the best result, and the next boiling treatment of 1 hour, the last 1 hour treatment with 1% NaOH solution. Optimum conditions of explosion method were 20kgf/$cm^2-1$ minute and 25kgf/$cm^2-1$ minute. Rice hull board made with exploded rice hull met the KS standard(KS F 3104, 1997) and showed the same strength as a control, PB. And also the 1 hour boiling treatment was more effective than the 1 hour treatment with 1% NaOH solution.

• Journal of the Korean Solar Energy Society
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• v.34 no.1
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• pp.81-90
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• 2014

The Jeju-Korea power system is a small-sized network with a system demand ranging from a autumn minimum of 350MW to a summer peak of 716MW. Because Jeju island is well exposed to north-east winds with high speed, applications to connect to Jeju power system are flooded. Considering physical/environmental constraints, Jeju Self-governing Province has also target for the wind power capacity of 1,350MW by 2020. It amounts to two or three times of Jeju average-demand power and wind power limit capacity announced by Korea Power Exchange (KPX) company. Wind farm connection agreements will be signed to maximize utilization of wind resource. In spite of submarine cable HVDC connected to Korea mainland, Jeju power system is independently operated by frequency and reserve control. This study reevaluates wind power limit based on the KPX criteria from 2016 to 2020. First of all wind power generation limit are affected by off-peak demand in Jeju power system. Also the possibility capacity rate of charging wind power output is evaluated by using energy storage system (ESS). As a result, in case of using 110MWh ESS, wind power limit increases 33~55MW(30~50% of ESS), wind power constraint energy decreases from 68,539MWh to 50,301MWh and wind farm capacity factor increases from 25.9 to 26.1% in 2020.

• Journal of the Korean Society of Safety
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• v.27 no.3
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• pp.49-56
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• 2012

The purpose of this paper is to present a model for operating an emergency power system(EPS) that can secure a sufficient power supply used in case of a fire by analyzing the status of power supplies for emergency and firefighting operations. Investigations on the one of the causes of the operational failure of firefighting systems show evidence of EPS. Generally, when power to a building is interrupted, EPS supplies the emergency load(excepted firefighting load) first. When a power outage and a fire occur simultaneously, the EPS must be able to supply both the emergency load and the firefighting load, especially the firefighting load to the end. However, in order to save construction costs, emergency power generators in apartment, commercial, and business buildings can satisfy only one of the required loads. In cases like this, when a power outage and a fire occur simultaneously, there is a danger of firefighting equipment not operating due to insufficient power supply from the emergency generator. Therefore, an EPS must have a reserved firefighting power that can supply both the firefighting and the emergency load. Such EPS, when faced with a danger of an overload, will shut down the supply to all or part of the emergency load, thus securing a continuous power supply to the firefighting equipment. The generator power system with reserved firefighting power (RFP) will also have an indicator to show that the selective control is being used. General power generation systems for emergency load and firefighting load were found to have a demand factor of 50-60% with a lump. However, when installing an EPS, the builders must choose the higher demand factor suggested according to the official approval demand factor of the building.

• Clean Technology
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• v.20 no.2
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• pp.97-102
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• 2014

Currently various studies are underway for dispensing high-viscosity phosphor. These studies have reported limitations and challenges in the dispensing process. The discharged amount of phosphor was approximately the same each time which is important for the implementation of high-efficiency white LED technology. This paper present high-viscosity phosphor dispensing process for white LED implementation by using electrostatic printing technology. The voltage controlled DOD (Drop-On-Demand) discharge experiment was studied to determine angle of drop meniscus at nozzle and dot diameter. With increase in Discharge voltage, the discharge angle of meniscus increased while dot diameter decreased. Therefore it can be concluded that we can control the discharge rate by controling the discharge angle of meniscus.