• Journal of the Korean Solar Energy Society
• /
• v.26 no.3
• /
• pp.1-8
• /
• 2006

The objective of this research is to study on the analysis of long-term performance characteristics of various solar thermal system for heating protected horticulture system for reducing heating cost, increasing the value of product by environment control, and developing advanced culture technology by deploying solar thermal system. Long term field test for the demonstration was carried out in horticulture complex in Jeju Island. Reliability and economic aspect of the system which was operated complementary with thermal storage and solar hot water generation were analyzed by investigating collector efficiency, operation performance, and control features. Optimum operating condition and its characteristics were closely investigated by changing the control condition based on the temperature difference which is the most important operating parameter. However, it is expected that, in high-insolation areas where large-scale ground storage is adaptable, solar system demonstrated in the research could be economically competitive and promisingly disseminate over various application areas.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.9 no.1
• /
• pp.79-87
• /
• 2004

The silkworm rearing and growth parameters of 63 multivoltine silkworm accessions under extended period of egg preservation at 5$^{\circ}C$ from 30 days to 45 days were studied. The results indicate that, nine accessions did not respond to extended period of egg preservation at low temperature and the remaining 54 accessions responded to the treatment and three rearings were conducted for comparision with the control; to estimate the effect of prolonged egg preservation at low temperature. The non-parametric tests statistics (Wilcoxon tests) was adopted for comparing the mean performance of treated batches (45 days) over the control (30 days). Highly significant variability was found among the accessions for all the parameters under study. The genetically controlled morphological characters were not altered in the treated batches, which were found to be on par with that of control. However, the total larval duration varied significantly over the control in 51 accessions. Similarly, the fifth age larval duration of 27 accessions showed decreasing trend compared to control. Altogether 41 accessions were found to be tolerant to long-term cold preservation upto 45 days, without showing any significant variation for morphological as well as essential quantitative traits. These accessions may be recommended for long-term egg preservation schedule up to 45 days, which will reduce the cost of conservation of these silkworm germplasm.

• Journal of Korean Society on Water Environment
• /
• v.23 no.3
• /
• pp.356-366
• /
• 2007

In this paper a methodology is developed to prioritize replacement of water distribution pipes according to the economical efficiency of replacement and assess the long-term effects of water main replacement policies on water distribution systems. The methodology is implemented with MATLAB to develop a computer algorithm which is used to apply the methodology to a case study water distribution system. A pipe break prediction model is used to estimate future costs of pipe repair and replacement, and the economically optimal replacement time of a pipe is estimated by obtaining the time at which the present worth of the total costs of repair and replacement is minimum. The equation for estimating the present worth of the total cost is modified to reflect the fact that a pipe can be replaced in between of failure events. The results of the analyses show that about 9.5% of the pipes in the case study system is required to be replaced within the planning horizon. Analyses of the yearly pipe replacement requirements for the case study system are provided along with the compositions of the replacement. The effects of water main replacement policies, for which yearly replacement length scenario and yearly replacement budget scenario are used, during a planning horizon are simulated in terms of the predicted number of pipe failures and the saved repair costs.

• Korean Journal of Adult Nursing
• /
• v.29 no.3
• /
• pp.278-289
• /
• 2017

Purpose: This study was designed to investigate whether there were differences among three oral care protocols on participants' oral health status (oral status, dry mouth, halitosis, saliva pH, microorganism growth in oral cavity) and tooth stain. The three protocols were: 1) oral solution of 4% normal saline, 2) 0.1% Chlorhexidine and 3) Tantum. Methods: A nonequivalent control group pretest-posttest design was utilized. A total of 55 elderly patients residing at long-term care facilities(19 in the 4% normal saline group, 17 in the 0.1% Chlorhexidine group, 19 in the Tantum group) received oral care daily for four weeks. Data were analyzed using SPSS/WIN 22.0 program. Results: The halitosis (${\chi}^2=10.71$, p=.005) and saliva pH (${\chi}^2=6.84$, p=.033) scores were significantly improved after the oral care with 4% normal saline. Conclusion: These findings indicate that if elderly patients in long-term care facilities have complaint of the discomfort of using Chlorhexidine or Tantum, 4% normal saline is as effective at the other two. This can also be cost effective as there were no differences among the protocols in oral status, dry mouth, tooth stain or microorganism growth in oral cavity.

• Journal of KIBIM
• /
• v.11 no.3
• /
• pp.75-90
• /
• 2021

A smart home system improves the elderly's quality of life by monitoring and analyzing their movements and health conditions with better health-care and social support services. Therefore, there has been an effort to adopt a smart home system for the independently living elderly. However, to the best of our knowledge, no study has investigated the usability of a smart home system on actual independently living elderly housing in long-term settings. Thus, this study aims to demonstrate the usability of a smart home system on independently living elders in living lab conditions. The BLE smart band and the BLE receiver were chosen for the smart home system to monitor the movement of the participants in their homes as well as to monitor the heart rates, step counts, sleep index. Nine independent living elderly from the senior welfare center in Kimjae participated in this living lab demonstration experiment for ten months. This demonstration experiment confirmed the effectiveness of low-cost and easily adoptable IoT-based BLE sensor sets on independent living elders and discussed the troubles and limitations of the experiment. By grasping the pros and cons of IoT-based BLE sensor sets, this study seeks to improve the accessibility and usability of smart home systems for the elderly population in independent living arrangements.

• Journal of the Korean Society of Systems Engineering
• /
• v.19 no.2
• /
• pp.18-31
• /
• 2023

Exploring artificial intelligence and machine learning for nuclear safety has witnessed increased interest in recent years. To contribute to this area of research, a machine learning model capable of accurately predicting nuclear power plant response with minimal computational cost is proposed. To develop a robust machine learning model, the Best Estimate Plus Uncertainty (BEPU) approach was used to generate a database to train three models and select the best of the three. The BEPU analysis was performed by coupling Dakota platform with the best estimate thermal hydraulics code RELAP/SCDAPSIM/MOD 3.4. The Code Scaling Applicability and Uncertainty approach was adopted, along with Wilks' theorem to obtain a statistically representative sample that satisfies the USNRC 95/95 rule with 95% probability and 95% confidence level. The generated database was used to train three models based on Recurrent Neural Networks; specifically, Long Short-Term Memory, Gated Recurrent Unit, and a hybrid model with Long Short-Term Memory coupled to Convolutional Neural Network. In this paper, the System Engineering approach was utilized to identify requirements, stakeholders, and functional and physical architecture to develop this project and ensure success in verification and validation activities necessary to ensure the efficient development of ML meta-models capable of predicting of the nuclear power plant response.

• Architectural research
• /
• v.24 no.3
• /
• pp.85-91
• /
• 2022

The public rental housing policy aims to provide the housing to the vulnerable class who do not have enough credit to own houses. The Korean government introduced new policies for housing supply to improve the availability of new houses. However, it is difficult to expand the supply because of the accumulated deficit of public rental housing. In this study, the economic feasibility of long-term public rental housing reconstruction projects was examined to ensure the economic and sustainable growth of public rental housing. The research found that the compensation for the accumulated deficit is needed. Also the research analyzed and identified the factors affecting the economic feasibility of reconstruction projects. The significant factors identified in this research are: the supply price of pre-sale/rental housing in the reconstruction project, total cost of the reconstruction project, and total floor area of the reconstruction project. According to the analysis results, it is necessary to increase the rent of existing long-term public rental housing, expand the government subsidy, increase the supply price of pre-sale/rental housing, and reduce the total project cost. However, there are limitations. For example, the fluctuations of construction market, residents' burden of housing costs, and the limit of the budget of the public housing authority. The increasing total Floor Area Ratio(FAR) limitation of the reconstruction project would be the realistic solution to the problem because it gives incentives to the reconstruction project.

• Journal of Electrical Engineering and Technology
• /
• v.8 no.1
• /
• pp.40-45
• /
• 2013

It is known that Reliability Differentiated Pricing (RDP) can improve the efficiency and benefits of consumers and producers. This paper examines the long-run social welfare maximization problem of the utility and presents a long-term reliability differentiated prices for firm capacity, based on customer outage costs. Then the applicability of the proposed pricing scheme is verified with a case study.

• Journal of Advanced Marine Engineering and Technology
• /
• v.39 no.4
• /
• pp.483-488
• /
• 2015

This paper implements a long-term monitoring system (LMS) for ship's engine performance analysis (SEPA) based on the web, for the purpose of the communication speed and engine maintenance. This system is composed of a simulator, monitoring module with a multi channel A/D converter, monitoring computer, network attached storage (NAS), RS485 serial and wireless internet communication system. The existing products monitor the information transmitted from pressure sensors installed in the upper parts of each of engines in the local or web computer, but have a delay in the communication speed and errors in long-term monitoring due to the large volume of sampling pressure data. To improve these problems, the monitoring computer saves the sampling pressure data received from the pressure sensors in NAS, monitors the long-term sampling data generated by the sectional down sampling method on a local computer, and transmits them to the web for long-term monitoring. Because this method has one tenth of the original sampling data, it will use memory with small capacity, save communication cost, monitor the long-term sampling data for 30 days, and as a result, make a great contribution to engine maintenance.

• IE interfaces
• /
• v.16 no.4
• /
• pp.400-410
• /
• 2003

Most of the demand forecasting which have been studied is about long-term time series over 15 years demand forecasting. In this paper, we set up the most optimal ARIMA model for the short-term time series demand forecasting and suggest demand forecasting system for short-term time series by appraising suitability and predictability. We are going to use the univariate ARIMA model in parallel with the bivariate transfer function model to improve the accuracy of forecasting. We also analyze the effect of advertisement cost, scale of branch stores, and number of clerk on the establishment of marketing policy by applying statistical methods. After then we are going to show you customer's needs, which are number of buying products. We have applied this method to forecast the annual sales of refrigerator in four branch stores of A company.