• Journal of Environmental Science International
• /
• v.9 no.3
• /
• pp.261-266
• /
• 2000

A kinetic study for nitrate removal by anion exchange resin was performed using continuous column reactors. Kinetic approach from the packed bed showed the reaction rate constant k$_1$ was 0.07~0.17 $\ell$/mgㆍhr and maximum exchange quantity q$_{o}$ was 27.75~31.81 mg/g. The results from the continuous column well agreed with that from the batch reactor. An economic analysis of the water treatment plant by anion exchange resin with a regenerating system was performed to design plant and process. Based on the treatment of 20 mg/$\ell$ nitrate-contained wastewater of 10,000 gallons per day to 2 mg/$\ell$, total capital cost and total annual cost are estimated to be 836 million wons and 211 million wons, respectively.y.

• Journal of Sensor Science and Technology
• /
• v.15 no.1
• /
• pp.40-46
• /
• 2006

This paper presents a novel fiber optic accelerometer system for monitoring vibration of large-size structures. The system is composed of one (or multiple) sensor head, a light control unit and a signal processing unit. The sensing mechanism of the sensor head is based on a novel integration of the moire fringe phenomenon with fiber optics to achieve a robust performance in addition to its immunity to EM interference, easy cabling, and low cost. In this paper, a prototype of the fiber optic accelerometer system has been developed successfully. A low-cost light control unit has been developed to drive the system's optic and electronic components. A unique algorithm has also been developed to derive the sensor's acceleration from the raw signals of the light control unit; it is implemented via a separate signal processing unit. Finally, the shaking table tests successfully demonstrate the performance and the potential of the moire fringe fiber optic sensor system to monitor the health of civil infrastructures.

• Geotechnical Engineering
• /
• v.11 no.2
• /
• pp.71-78
• /
• 1995

In this paper, a study was performed on classifying a rock mass into multiple classes as in rock mass classification systems, such as RMR system and Q system etc. In a situation with only limited quantitative data available, it was sought to employ a way of incorporating qualitative data in a systematical and reasonable manner. It is based on the realm of Geostatistics. In particular, indicator kriging technique, which is one of non-parametric approaches, was used. As a selection criterion for an optimal classification, the cost of errors was adopted. As a result, the binary rock classification method developed before was extended and generalized for multiple rock classification with its total number of classes unlimited.

• Biomedical Science Letters
• /
• v.26 no.4
• /
• pp.275-287
• /
• 2020

Since its introduction in the forensic field, quantitative PCR (qPCR) has played an essential role in DNA analysis. Quality of DNA should be evaluated before short tandem repeat (STR) profiling to obtain reliable results and reduce unnecessary costs. To this end, various human DNA quantification kits have been developed. Among these kits, the PowerQunat® System was designed not only to determine the total amount of human DNA and human male DNA from a forensic evidence item, but also to offer data about degradation of DNA samples. However, a crucial limitation of the PowerQunat® System is its high cost. Therefore, to minimize the cost of DNA quantification, we evaluated kit performance using a reduced volume of reagents (1/2-volume) using DNA samples of varying types and concentrations. Our results demonstrated that the low-volume method has almost comparable performance to the manufacturer's method for human DNA quantification, human male DNA quantification, and DNA degradation index. Furthermore, using a reduced volume of regents, it is possible to run 2 times more reactions per kit. We expect the proposed low-volume method to cut costs in half for laboratories dealing with large numbers of DNA samples.

• Journal of the Korean Society of Mechanical Technology
• /
• v.20 no.6
• /
• pp.809-817
• /
• 2018

The model predictive controller performance of the mobile robot is set to an arbitrary value because it is difficult to select an accurate value with respect to the controller parameter. The general model predictive control uses a quadratic cost function to minimize the difference between the reference tracking error and the predicted trajectory error of the actual robot. In this study, we construct a predictive controller by transforming it into a quadratic programming problem considering velocity and acceleration constraints. The control parameters of the predictive controller, which determines the control performance of the mobile robot, are used a simple weighting matrix Q, R without the reference model matrix $A_r$ by applying a quadratic cost function from which the reference tracking error vector is removed. Therefore, we designed the predictive controller 1 and 2 of the mobile robot considering the constraints, and optimized the controller parameters of the predictive controller using a genetic algorithm with excellent optimization capability.

• International conference on construction engineering and project management
• /
• 2022.06a
• /
• pp.204-212
• /
• 2022

Recently, the Korean government has been actively promoting the smart city as their strategic agenda. However, to build smart cities that are greener, the authors believe it is essential to rapidly transit conventional energy sources such as fossil fuels to renewable energy. Although there is a big potential for Offshore wind in Korea, there has not been a full-scale commercial offshore wind farm until today. Since Korea is relatively a new market compared to the EU, it can be risky for developers. The authors will introduce risk management best practices in the offshore wind industry applicable to the Korean environment. This paper will mainly introduce an offshore wind project size of 99 MW. The project is expecting a Finance Close (FC) in Q3 2022, so the project team has prepared a risk register with over 150 risks and levers throughout the project lifecycle. Overall risks include risks with Development Expenditure (DEVEX) impact, a Capital Expenditure (CAPEX) impact, and an Operating Expenditure (OPEX) impact. Based on the identified risks, a more qualitative assessment of Cost and Schedule Impact was conducted. In conclusion, a Monte Carlo simulation was performed to propose a quantitative risk assessment to evaluate a benchmark contingency of the project cost.

• Quality Improvement in Health Care
• /
• v.5 no.2
• /
• pp.202-215
• /
• 1998

Purpose : To shorten processing time for variety of medical affairs of the patient at the outpatient clinic of a big hospital is very important to qualify medical care of the patient. Therefore, patient's waiting time for drug delivery after doctor's prescription is often utilized as a strong tool to evaluate patient satisfaction with a medical care provided. We performed this study to investigate factors influencing patient satisfaction related with waiting time for drug delivery. Methods : The data were collected from July 21 to August 12, 1998. A total 535 patients or their families who visited outpatient clinics of Inha University Hospital were subjected to evaluate the drug delivery time and the level of their satisfaction related, which were compared with those objectively evaluated by Quality Improvement Team. The reliability of the scale was tested with Cronbach's alpha, and the data were analyzed using frequency, t-test, ANOVA, correlation analysis and multiple regression. Results : The mean drug delivery time subjectively evaluated by the patient (16.1 13.0 min) was longer than that objectively evaluated (10.9 7.6 min) by 5.2 min. Drug delivery time objectively evaluated was influenced by the prescription contents, total amount or type of drug dispensed, etc, as expected. The time discrepancy between two evaluations was influenced by several causative factors. One of those proved to be a patient's late response to the information from the pharmacy which the drug is ready to deliver. Interestingly, this discrepancy was found to be more prominent especially when waiting place for drug delivery was not less crowded. Other factors, pharmaceutical counseling at the pharmacy, emotional status or behavior of a patient while he waits for the medicine, were also found to influence the time subjectively evaluated. Regarding the degree of patient satisfaction with the drug delivery, majority of patients accepted drug delivery time with less than 10 min. It was also found to be influenced by emotional status of the patient as well as kindness or activity of pharmaceutical counselor. Conclusion : The results show that, besides prescription contents, behavior pattern or emotional status of a patient, environment of the waiting place, and quality of pharmaceutical counseling at the pharmacy, may influence the patient's subjective evaluation of waiting time for drug delivery and his satisfaction related with the service in the big hospital. In order to improve patient satisfaction related with waiting time for drug delivery, it will be cost effective to qualify pharmaceutical counseling and information system at the drug delivery site or waiting place rather than to shorten the real processing time within the pharmacy.

• New & Renewable Energy
• /
• v.8 no.2
• /
• pp.33-43
• /
• 2012

Why solar companies preferred vertical integration of whole value chain? Major solar companies have built internally strong vertical integration of entire PV value chain. We raise a question whether such integration increases the corporate value and whether market situation affects the result. To test these questions, we conducted multi-variant analysis where characteristic factors mainly affect the corporate value measured in terms of Tobin'Q, based on the financial and non-financial data of PV companies listed in US stock market between 2005 and 2010. We hypothesize that since integration increases the overall efficiency but decreases the flexibility to adjust to various market situation, the combined effect of the efficiency gain and the flexibility loss ultimately determines the sign of integration effect on the corporate vale. We infer that the combined effect will be influenced heavily by business cycle, as in boom market (Seller's market) the efficiency gain may be larger than the flexibility loss and vice versa in bust market. We test whether the sign of combined effect changes after the year of 2009 and which factors influence most the sign. Year of 2009 is known as the year when market shifted from Seller's to Buyer's market. We show that 1) integration increases corporate value in general but after 2009 integration significantly decreases the value, 2) the ratios such as Production/Total Cost, Cash turnover period chosen for reversal of the flexibility measure are negatively affect Tobin's Q and especially stronger after 2009. This shows the flexibility improves corporate value and stronger in the recess period (Buyer's market). These results imply that solar company should set up integration strategy considering the tradeoff between efficiency and flexibility and the impact of the business cycle on both factors. Strategy only based on the price competitiveness determined in boom time can bring undesirable outcomes to the company. In addition, Strategic alliances in some value chains as a flexible bondage should be taken in account as complementary choice to the rigid integration.

• 대한방사선치료학회:학술대회논문집
• /
• 2005.06a
• /
• pp.19-22
• /
• 2005

Introduction: Daily Q.A is the important step which must be preceded in a radiation treatment. Specially, radiation output measurement and laser alignment, SSD indicator related to a patient set-up recurrence must be confirmed for a reasonable radiation treatment. Daily Q.A proceeds correctness and a prompt way, and needs an objective measurement basis. Manufacture of the device which can facilitate confirmation of output measurement and appliances check at one time was requested. Methods and Materials: Produced the phantom formal daily check device which can confirm a lot of appliances check (output measurement and laser alignment, field size, SSD indicator) with one time of set up at a time, and measurement observed a linear accelerator (4 machine) for four months and evaluated efficiency. Result: We were able to confirm an laser alignment, field size, SSD indicator check at the same time, and out put measurement was possible with the same set up, so daily Q.A time was reduced, and were able to confirm an objective basis about each item measurement. As a result of having measured for four months, output measurement within ${\pm}\;2\%$, and measured laser alignment, field size, SSD indicator in range within ${\pm}\;1mm$. Conclusion: We can enforce output measurement and appliances check conveniently and time was reduced and was able to raise efficiency of business. We were able to bring n cost reduction by substitution expensive commercialized equipment. Further It is necessary to makes a product as strong and slight materials, and improve convenience of use.

• Journal of Korean Society of Water and Wastewater
• /
• v.29 no.6
• /
• pp.601-608
• /
• 2015

Pollutants removal efficiency in pretreatment(GAC filter, multi-media filter, disk filter) and RO facilities was investigated for the Jeju Samyang spring water source where raw water intake has been stopped due to sea water intrusion. In addition, preliminary feasibility analysis was conducted between RO and groundwater intake systems. Turbidity removal in 4 different pretreatment processes was less than 25% due to low concentration of turbidity(i.e., less than 0.21 NTU), while multi-media filter is recommended for the pretreatment facility based on the low organic content in raw water as well as cheaper operation and maintenance cost. The average concentration of $Cl^-$ in raw water was 691.4 mg/L, while that of RO permeate was 9.1 mg/L(i.e., removal efficiency was 98.4%). In addition, TDS removal efficiency was 98.1%, which was quite high. The production cost for RO system($Q=4,000m^3/d$) was $362.1won/m^3$ considering installation, operation and maintenance cost for 30 years. While that of groundwater was $262.6won/m^3$ which was low compared to the RO system. However, it is recommended to introduce RO system for Samyang water source rather than new groundwater development because Samyang water source has been discharged to the sea without any usage, while groundwater can be used for other purpose as a sustainable water source.